[Federal Register Volume 89, Number 96 (Thursday, May 16, 2024)]
[Rules and Regulations]
[Pages 42932-43297]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-07002]



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Vol. 89

Thursday,

No. 96

May 16, 2024

Part II





Environmental Protection Agency





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40 CFR Parts 60 and 63





 New Source Performance Standards for the Synthetic Organic Chemical 
Manufacturing Industry and National Emission Standards for Hazardous 
Air Pollutants for the Synthetic Organic Chemical Manufacturing 
Industry and Group I & II Polymers and Resins Industry; Final Rule

  Federal Register / Vol. 89, No. 96 / Thursday, May 16, 2024 / Rules 
and Regulations  

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60 and 63

[EPA-HQ-OAR-2022-0730; FRL-9327-02-OAR]
RIN 2060-AV71


New Source Performance Standards for the Synthetic Organic 
Chemical Manufacturing Industry and National Emission Standards for 
Hazardous Air Pollutants for the Synthetic Organic Chemical 
Manufacturing Industry and Group I & II Polymers and Resins Industry

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This action finalizes amendments to the New Source Performance 
Standards (NSPS) that apply to the Synthetic Organic Chemical 
Manufacturing Industry (SOCMI) and amendments to the National Emission 
Standards for Hazardous Air Pollutants (NESHAP) that apply to the SOCMI 
(more commonly referred to as the Hazardous Organic NESHAP or HON) and 
Group I and II Polymers and Resins (P&R I and P&R II, respectively) 
Industries. The EPA is finalizing decisions resulting from the Agency's 
technology review of the HON and the P&R I and P&R II NESHAP, and its 
review of the NSPS that apply to the SOCMI. The EPA is also finalizing 
amendments to the NSPS for equipment leaks of volatile organic 
compounds (VOC) in SOCMI based on its reconsideration of certain issues 
raised in an administrative petition for reconsideration. Furthermore, 
the EPA is finalizing emission standards for ethylene oxide (EtO) 
emissions and chloroprene emissions after considering the results of a 
risk assessment for the HON and for Neoprene Production processes 
subject to the P&R I NESHAP, and is finalizing a fenceline monitoring 
work practice standard for certain hazardous air pollutants (HAP). 
Lastly, the EPA is finalizing the removal of exemptions from standards 
for periods of startup, shutdown, and malfunction (SSM), adding work 
practice standards for such periods where appropriate, finalizing 
standards for previously unregulated HAP, and adding provisions for 
electronic reporting of performance test reports and periodic reports.

DATES: This final rule is effective on July 15, 2024. The incorporation 
by reference (IBR) of certain publications listed in the rule is 
approved by the Director of the Federal Register as of July 15, 2024. 
The incorporation by reference of certain other material listed in the 
rule was approved by the Director of the Federal Register as of October 
17, 2000 and November 16, 2007.

ADDRESSES: The U.S. Environmental Protection Agency (EPA) has 
established a docket for this action under Docket ID No. EPA-HQ-OAR-
2022-0730. All documents in the docket are listed on the https://www.regulations.gov/ website. Although listed, some information is not 
publicly available, e.g., Confidential Business Information (CBI) or 
other information whose disclosure is restricted by statute. Certain 
other material, such as copyrighted material, is not placed on the 
internet and will be publicly available only in hard copy form. 
Publicly available docket materials are available either electronically 
through https://www.regulations.gov/, or in hard copy at the EPA Docket 
Center, WJC West Building, Room Number 3334, 1301 Constitution Ave. NW, 
Washington, DC. The Public Reading Room hours of operation are 8:30 
a.m. to 4:30 p.m. Eastern Standard Time, Monday through Friday. The 
telephone number for the Public Reading Room is (202) 566-1744, and the 
telephone number for the EPA Docket Center is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: For questions about the HON and SOCMI 
NSPS, contact U.S. EPA, Attn: Mr. Andrew Bouchard, Mail Drop: Sector 
Policies and Programs Division (E143-01), 109 T.W. Alexander Drive, 
P.O. Box 12055, RTP, North Carolina 27711; telephone number: (919) 541-
4036; and email address: [email protected]. For questions about 
the P&R I and P&R II NESHAP, contact U.S. EPA, Attn: Ms. Njeri Moeller, 
Mail Drop: Sector Policies and Programs Division (E143-01), 109 T.W. 
Alexander Drive, P.O. Box 12055, RTP, North Carolina 27711; telephone 
number: (919) 541-1380; and email address: [email protected]. For 
specific information regarding the risk modeling methodology, contact 
U.S. EPA, Attn: Mr. Matthew Woody, Mail Drop: Health and Environmental 
Impacts Division (C539-02), 109 T.W. Alexander Drive, P.O. Box 12055, 
RTP, North Carolina 27711; telephone number: (919) 541-1535; and email 
address: [email protected].

SUPPLEMENTARY INFORMATION: 
    Preamble acronyms and abbreviations. We use multiple acronyms and 
terms in this preamble. While this list may not be exhaustive, to ease 
the reading of this preamble and for reference purposes, the EPA 
defines the following terms and acronyms here:

ACS American Community Survey
AERMOD American Meteorological Society/EPA Regulatory Model 
dispersion modeling system
ANSI American National Standards Institute
APCD air pollution control device
API American Petroleum Institute
ASME American Society of Mechanical Engineers
BACT best available control technology
BLR basic liquid epoxy resins
BPT benefit per-ton
BSER best system of emissions reduction
BTEX benzene, toluene, ethylbenzene, and xylenes
CAA Clean Air Act
CBI confidential business information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CMPU chemical manufacturing process unit
CO carbon monoxide
CO2 carbon dioxide
CPI consumer price index
CRA Congressional Review Act
EAV equivalent annual value
ECHO Enforcement and Compliance History Online
EFR external floating roof
EIS Emission Information System
EPA Environmental Protection Agency
EPPU elastomer product process unit
ERT Electronic Reporting Tool
EtO ethylene oxide
FTIR fourier transform infrared
HAP hazardous air pollutant(s)
HON Hazardous Organic NESHAP
HQ hazard quotient
HQREL hazard quotient reference exposure level
IBR incorporation by reference
ICR information collection request
IFR internal floating roof
IRIS Integrated Risk Information System
ISA Integrated Science Assessment
km kilometer
LAER lowest achievable emissions rate
lb/hr pound per hour
lb/yr pound per year
LDAR leak detection and repair
LDEQ Louisiana Department of Environmental Quality
LEL lower explosive limit
MACT maximum achievable control technology
MDL method detection limit
MERP monomer emission reduction project
MIR maximum individual lifetime [cancer] risk
MON Miscellaneous Organic Chemical Manufacturing NESHAP
MTVP maximum true vapor pressure
NAICS North American Industry Classification System
NAAQS National Ambient Air Quality Standards
NATTS National Air Toxic Trends Station
NEI National Emissions Inventory
NESHAP national emission standards for hazardous air pollutants
NOX nitrogen oxides
N2O nitrous oxide

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NPDES national pollutant discharge elimination system
NRDC Natural Resources Defense Council
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
NYSDEC New York State Department of Environmental Conservation
OAR Office of Air and Radiation
OEL open-ended valves or lines
OGI optical gas imaging
OIG Office of Inspector General
OMB Office of Management and Budget
P&R I Group I Polymers and Resins
P&R II Group II Polymers and Resins
PDF portable document format
PMPU polyether polyol manufacturing process unit
POM polycyclic organic matter
ppbv parts per billion by volume
ppm parts per million
ppmv parts per million by volume
ppmw parts per million by weight
PRA Paperwork Reduction Act
psig pounds per square inch gauge
PRD pressure relief device
PV present value
RACT reasonably available control technology
RDL representative detection limit
REL reference exposure level
RFA Regulatory Flexibility Act
RIA Regulatory Impact Analysis
RTO regenerative thermal oxidizer
RTR risk and technology review
SCAQMD South Coast Air Quality Management District
scfm standard cubic feet per minute
scmm standard cubic meter per minute
SOCMI Synthetic Organic Chemical Manufacturing Industry
SO2 sulfur dioxide
SSM startup, shutdown, and malfunction
TAC Texas Administrative Code
TCEQ Texas Commission on Environmental Quality
TCI total capital investment
TOC total organic compounds
TOSHI target organ-specific hazard index
tpy tons per year
TRE total resource effectiveness
TRI Toxics Release Inventory
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
U.S.C. United States Code
VCS voluntary consensus standards
VOC volatile organic compound(s)
WSR wet strength resins
WWTP wastewater treatment plant

    Background information. On April 25, 2023, the EPA proposed 
amendments to the NSPS that apply to the SOCMI, and amendments to the 
HON and P&R I and P&R II NESHAP. In this action, we are finalizing 
decisions and revisions for the rule. We summarize some of the more 
significant comments we timely received regarding the proposed rule and 
provide our responses in this preamble. A summary of all other public 
comments on the proposal and the EPA's responses to those comments is 
available in the document titled Summary of Public Comments and 
Responses for New Source Performance Standards for the Synthetic 
Organic Chemical Manufacturing Industry and National Emission Standards 
for Hazardous Air Pollutants for the Synthetic Organic Chemical 
Manufacturing Industry and Group I & II Polymers and Resins Industry, 
Docket ID No. EPA-HQ-OAR-2022-0730. A ``track changes'' version of the 
regulatory language that incorporates the changes in this action is 
available in the docket.
    Organization of this document.
    The information in this preamble is organized as follows:

I. General Information
    A. Executive Summary
    B. Does this action apply to me?
    C. Where can I get a copy of this document and other related 
information?
    D. Judicial Review and Administrative Reconsideration
II. Background
    A. What is the statutory authority for this action?
    B. What are the source categories and how did the previous 
standards regulate emissions?
    C. What changes did we propose in our April 25, 2023, proposal?
III. What is included in this final rule?
    A. What are the final rule amendments based on the risk review 
for the SOCMI and Neoprene Production source categories NESHAP?
    B. What are the final rule amendments based on the technology 
review for the SOCMI, P&R I, and P&R II source categories NESHAP 
pursuant to CAA section 112(d)(6) and NSPS reviews for the SOCMI 
source category pursuant to CAA section 111(b)(1)(B)?
    C. What are the final rule amendments pursuant to CAA sections 
112(d)(2) and (3), and 112(h) for the SOCMI, P&R I, and P&R II 
source categories?
    D. What are the final rule amendments addressing emissions 
during periods of SSM?
    E. What are the final amendments addressing the NSPS Subparts VV 
and VVa reconsideration?
    F. What other changes have been made to the NESHAP and NSPS?
    G. What are the effective and compliance dates of the standards?
IV. What is the rationale for our final decisions and amendments for 
the SOCMI, P&R I, and P&R II source categories?
    A. Residual Risk Review for the SOCMI and Neoprene Production 
Source Categories NESHAP
    B. Technology Review for the SOCMI, P&R I, and P&R II Source 
Categories NESHAP and NSPS Review for the SOCMI Source Category
    C. Amendments Pursuant to CAA Section 112(d)(2) and (3) and 
112(h) for the SOCMI, P&R I, and P&R II Source Categories NESHAP
    D. Amendments Addressing Emissions During Periods of SSM
    E. Amendments Addressing NSPS Subparts VV and VVa 
Reconsideration
    F. Other Amendments to the NESHAP and NSPS
V. Summary of Cost, Environmental, and Economic Impacts and 
Additional Analyses Conducted
    A. What are the affected sources?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
    F. What analysis of environmental justice did we conduct?
    G. Children's Environmental Health
VI. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 14094: Modernizing Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination with 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children from 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations that 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act (NTTAA) and 
1 CFR part 51
    J. Executive Order 12898: Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations and Executive Order 14096: Revitalizing Our Nation's 
Commitment to Environmental Justice for All
    K. Congressional Review Act (CRA)

I. General Information

A. Executive Summary

1. Purpose of the Regulatory Action
    The source categories that are the subject of this final action are 
the SOCMI and various polymers and resins manufacturing source 
categories. The SOCMI source category includes chemical manufacturing 
processes producing commodity chemicals while the polymers and resins 
manufacturing source categories covered in this action include 
elastomers production processes and resin production processes that use 
epichlorohydrin feedstocks (see sections I.B and II.B of this preamble 
for detailed information about these source categories). The EPA has 
previously promulgated maximum achievable control technology (MACT) 
standards for certain processes in the SOCMI source category in the HON 
rulemaking at 40 Code of Federal Regulations (CFR) part 63, subparts F, 
G, and H. In 1994, the EPA finalized MACT standards in subparts F, G, 
and

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H for SOCMI processes (59 FR 19454),\1\ and the Agency completed a 
residual risk and technology review (RTR) for these NESHAP in 2006 (71 
FR 76603). In 1995, the EPA finalized MACT standards in the P&R II 
NESHAP (40 CFR part 63, subpart W) for epoxy resin and non-nylon 
polyamide resin manufacturing processes (60 FR 12670), and the Agency 
completed a residual RTR for these standards in 2008 (73 FR 76220). In 
1996, the EPA finalized MACT standards in the P&R I NESHAP (40 CFR part 
63, subpart U) for various elastomer manufacturing processes (61 FR 
46906), and the Agency completed residual RTRs for these standards in 
2008 and 2011 (73 FR 76220 and 76 FR 22566).
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    \1\ Around the same time, the EPA set MACT standards for 
equipment leaks from certain non-SOCMI processes at chemical plants 
regulated under 40 CFR part 63, subpart I (59 FR 19587).
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    The EPA has also promulgated NSPS for certain processes in the 
SOCMI source category. In 1983, the EPA finalized NSPS (40 CFR part 60, 
subpart VV) for equipment leaks of VOC in SOCMI (48 FR 48328). In 1990, 
the EPA finalized NSPS (40 CFR part 60, subparts III and NNN) for VOC 
from air oxidation unit processes and distillation operations (55 FR 
26912 and 55 FR 26931). In 1993, the EPA finalized NSPS (40 CFR part 
60, subpart RRR) for VOC from reactor processes (58 FR 45948). In 2007, 
the EPA promulgated NSPS (40 CFR part 60, subpart VVa) for VOC from 
certain equipment leaks (72 FR 64883), which reflect the EPA's review 
and revision of the standards in 40 CFR part 60, subpart VV.
    The statutory authority for this action is sections 111, 112, 
301(a)(1), and 307(d)(7)(B) of the CAA. Section 111(b)(1)(B) of the CAA 
requires the EPA to promulgate standards of performance for new sources 
in any category of stationary sources that the Administrator has listed 
pursuant to 111(b)(1)(A). Section 111(a)(1) of the CAA provides that 
these performance standards are to ``reflect[ ] the degree of emission 
limitation achievable through the application of the best system of 
emission reduction which (taking into account the cost of achieving 
such reduction and any nonair quality health and environmental impact 
and energy requirements) the Administrator determines has been 
adequately demonstrated.'' We refer to this level of control as the 
best system of emissions reduction or ``BSER.'' Section 111(b)(1)(B) of 
the CAA requires the EPA to ``at least every 8 years, review and, if 
appropriate, revise'' the NSPS.
    For NESHAP, CAA section 112(d)(2) requires the EPA to establish 
MACT standards for listed categories of major sources of HAP. Section 
112(d)(6) of the CAA requires the EPA to review standards promulgated 
under CAA section 112, and revise them ``as necessary (taking into 
account developments in practices, processes, and control 
technologies),'' no less often than every eight years following 
promulgation of those standards. This is referred to as a ``technology 
review'' and is required for all standards established under CAA 
section 112. Section 112(f) of the CAA requires the EPA to assess the 
risk to public health remaining after the implementation of MACT 
emission standards promulgated under CAA section 112(d)(2). If the MACT 
standards for a source category do not provide ``an ample margin of 
safety to protect public health,'' the EPA must also promulgate health-
based standards for that source category to further reduce risk from 
HAP emissions.
    Section 301(a)(1) of the CAA authorizes the Administrator to 
prescribe such regulations as are necessary to carry out his functions 
under the CAA. Section 307(d)(7)(B) of the CAA requires the 
reconsideration of a rule only if the person raising an objection to 
the rule can demonstrate that it was impracticable to raise such 
objection during the period for public comment or if the grounds for 
the objection arose after the comment period (but within the time 
specified for judicial review), and if the objection is of central 
relevance to the outcome of the rule.
    The final new NSPS for SOCMI equipment leaks, air oxidation unit 
processes, distillation operations, and reactor processes (i.e., NSPS 
subparts VVb, IIIa, NNNa, and RRRa, respectively) are based on the 
Agency's review of the current NSPS (subparts VVa, III, NNN, and RRR) 
pursuant to CAA section 111(b)(1)(B), which requires that the EPA 
review the NSPS every eight years and, if appropriate, revise them. In 
addition, the EPA is finalizing amendments to the NSPS for equipment 
leaks of VOC in SOCMI based on its reconsideration of certain aspects 
of subparts VV and VVa that were raised in an administrative petition 
which the Agency granted pursuant to section 307(d)(7)(B) of the CAA. 
The final amendments to the HON (NESHAP subparts F, G, H, and I), the 
P&R I NESHAP (NESHAP subpart U), and the P&R II NESHAP (NESHAP subpart 
W) are based on the Agency's review of the current NESHAP (subparts F, 
G, H, I, U, and W) pursuant to CAA sections 112(d) and (f).
    Due to the development of the EPA's Integrated Risk Information 
System (IRIS) inhalation unit risk estimate (URE) for chloroprene in 
2010, the EPA conducted a second CAA section 112(f) risk review for the 
SOCMI source category and Neoprene Production source category. In the 
first step of the CAA section 112(f)(2) determination of risk 
acceptability for this rulemaking, the use of the 2010 chloroprene risk 
value resulted in the EPA identifying unacceptable cancer risk driven 
by chloroprene emissions from the sole affected source producing 
neoprene subject to the P&R I NESHAP.\2\ Consequently, the final 
amendments to the P&R I NESHAP address the EPA review of additional 
control technologies, beyond those analyzed in the technology review 
conducted for the P&R I source category, to address the unacceptable 
risk and achieve an ample margin of safety to protect public health at 
that affected source.
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    \2\ As discussed in section III.B of the proposal preamble (see 
88 FR 25080, April 25, 2023), chloroprene emissions from HON 
processes do not on their own present unacceptable cancer risk from 
the SOCMI source category.
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    Additionally, in 2016, the EPA updated the IRIS inhalation URE for 
EtO. In the first step of the CAA section 112(f)(2) determination of 
risk acceptability for this rulemaking, the use of the updated 2016 EtO 
risk value resulted in the EPA identifying unacceptable cancer risk 
driven by EtO emissions from HON processes. Consequently, the final 
amendments to the HON also address the EPA review of additional control 
technologies, beyond those analyzed in the technology review conducted 
for the SOCMI source category, to address the unacceptable risk and 
achieve an ample margin of safety to protect public health at SOCMI and 
P&R I affected sources.
2. Summary of the Major Provisions of the Regulatory Action In Question
    The most significant amendments that we are finalizing are 
described briefly below. However, all of our final amendments, 
including amendments to remove exemptions for periods of SSM, are 
discussed in detail with rationale in section IV of this preamble or in 
the document titled Summary of Public Comments and Responses for New 
Source Performance Standards for the Synthetic Organic Chemical 
Manufacturing Industry and National Emission Standards for Hazardous 
Air Pollutants for the Synthetic Organic Chemical Manufacturing 
Industry and Group I & II Polymers and Resins Industry, which is 
available in the docket for this rulemaking.

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a. HON
    We are finalizing amendments to the HON for heat exchange systems, 
process vents, storage vessels, transfer racks, wastewater, and 
equipment leaks.
i. NESHAP Subpart F
     As detailed in section II.B.1.a of this preamble, NESHAP 
subpart F contains provisions to determine which chemical manufacturing 
processes at a facility are subject to the HON, monitoring requirements 
for HAP (i.e., HAP listed in Table 4 of NESHAP subpart F) that may leak 
into cooling water from heat exchange systems, and requirements for 
maintenance wastewater. For NESHAP subpart F, we are finalizing:
     compliance dates for all of the HON requirements in this 
action (see 40 CFR 63.100(k)(10) through (12); and section III.G of 
this preamble).
     the moving of all the definitions from NESHAP subparts G 
and H (i.e., 40 CFR 63.111 and 40 CFR 63.161, respectively) into the 
definition section of NESHAP subpart F (see 40 CFR 63.101; and sections 
III.F and IV.F of this preamble).
     a new definition for ``in ethylene oxide service'' (for 
equipment leaks, heat exchange systems, process vents, storage vessels, 
and wastewater) (see 40 CFR 63.101; and sections III.A and IV.A of this 
preamble).
     new operating and monitoring requirements for flares (see 
40 CFR 63.108; and sections III.C and IV.C of this preamble).
     sampling and analysis procedures for owners and operators 
to demonstrate that process equipment does, or does not, meet the 
definition of being ``in ethylene oxide service'' (see 40 CFR 63.109; 
and sections III.A and IV.A of this preamble).
    For heat exchange systems, we are finalizing:
     requirements that owners or operators must use the 
Modified El Paso Method and repair leaks of total strippable 
hydrocarbon concentration (as methane) in the stripping gas of 6.2 
parts per million by volume (ppmv) or greater (see 40 CFR 63.104(g) 
through (j); and sections III.B.1 and IV.B of this preamble).
     requirements for heat exchange systems in EtO service that 
owners or operators must conduct more frequent leak monitoring (weekly 
instead of quarterly) and repair leaks of total strippable hydrocarbon 
concentration (as methane) in the stripping gas of 6.2 ppmv or greater 
within 15 days from the sampling date (in lieu of the previous 45-day 
repair requirement after receiving results of monitoring indicating a 
leak in the HON), and delay of repair is not allowed unless the 
equipment can be isolated such that it is no longer in EtO service (see 
40 CFR 63.104(g)(6) and (h)(6); and sections III.A.1 and IV.A of this 
preamble).
     a provision allowing use of the previous leak monitoring 
requirements for heat exchange systems at 40 CFR 63.104(b) in limited 
instances in lieu of using the Modified El Paso Method for heat 
exchange systems cooling process fluids that will remain in the cooling 
water if a leak occurs (see 40 CFR 63.104(l); and sections III.B.1 and 
IV.B of this preamble).
ii. NESHAP Subpart G
    As detailed in section II.B.1.b of this preamble, NESHAP subpart G 
contains requirements for process vents, storage vessels, transfer 
racks, wastewater streams, and closed vent systems.
    For process vents, we are finalizing:
     the removal of the 50 ppmv and 0.005 standard cubic meter 
per minute (scmm) Group 1 process vent thresholds from the Group 1 
process vent definition, and instead we are requiring owners and 
operators of process vents that emit greater than or equal to 1.0 pound 
per hour (lb/hr) of total organic HAP to reduce emissions of organic 
HAP using a flare meeting the operating and monitoring requirements for 
flares in NESHAP subpart F; or reduce emissions of total organic HAP or 
total organic compounds (TOC) by 98 percent by weight or to an exit 
concentration of 20 ppmv, (see 40 CFR 63.101 and 40 CFR 63.113(a)(1) 
and (2); and sections III.B.1 and IV.B of this preamble).
     the removal of the total resource effectiveness (TRE) 
concept in its entirety (see 40 CFR 63.113(a)(4); and sections III.B.1 
and IV.B of this preamble).
     an emission standard of 0.054 nanograms per dry standard 
cubic meter (ng/dscm) at 3 percent oxygen (toxic equivalency basis) for 
dioxins and furans from chlorinated process vents (see 40 CFR 
63.113(a)(5); and sections III.C and IV.C of this preamble).
     requirements that owners and operators must reduce 
emissions of EtO from process vents in EtO service by either: (1) 
Venting emissions through a closed-vent system to a control device that 
reduces EtO by greater than or equal to 99.9 percent by weight, to a 
concentration less than 1 ppmv for each process vent, or to less than 5 
pound per year (lb/yr) for all combined process vents per chemical 
manufacturing process unit (CMPU); or (2) venting emissions through a 
closed-vent system to a flare meeting the operating and monitoring 
requirements for flares in NESHAP subpart F (see 40 CFR 63.113(j), 40 
CFR 63.108, and 40 CFR 63.124; and sections III.A.1 and IV.A of this 
preamble).\3\
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    \3\ We are also removing the option to allow use of a design 
evaluation in lieu of performance testing to demonstrate compliance 
for controlling various emission sources in EtO service. In 
addition, owners or operators that choose to control emissions with 
a non-flare control device are required to conduct an initial 
performance test on each control device in EtO service to verify 
performance at the required level of control, and are required to 
conduct periodic performance testing on non-flare control devices in 
EtO service every 5 years (see 40 CFR 63.124).
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     a work practice standard for maintenance vents requiring 
that, prior to opening process equipment to the atmosphere, the 
equipment must either: (1) Be drained and purged to a closed system so 
that the hydrocarbon content is less than or equal to 10 percent of the 
lower explosive limit (LEL); (2) be opened and vented to the atmosphere 
only if the 10-percent LEL cannot be demonstrated and the pressure is 
less than or equal to 5 pounds per square inch gauge (psig), provided 
there is no active purging of the equipment to the atmosphere until the 
LEL criterion is met; (3) be opened when there is less than 50 lbs of 
VOC that may be emitted to the atmosphere; or (4) for installing or 
removing an equipment blind, depressurize the equipment to 2 psig or 
less and maintain pressure of the equipment where purge gas enters the 
equipment at or below 2 psig during the blind flange installation, 
provided none of the other work practice standards can be met (see 40 
CFR 63.113(k); and sections III.C and IV.C of this preamble).
     requirements that owners and operators of process vents in 
EtO service are allowed to use the maintenance vent work practice 
standards; however, owners and operators are prohibited from releasing 
more than 1.0 ton of EtO from all maintenance vents combined on a 
facility basis in any consecutive 12-month period (see 40 CFR 
63.113(k)(4); and sections III.A.1 and IV.A of this preamble).
    For storage vessels, we are finalizing:
     requirements that owners and operators must reduce 
emissions of EtO from storage vessels in EtO service by either: (1) 
Venting emissions through a closed-vent system to a control device that 
reduces EtO by greater than or equal to 99.9 percent by weight or to a 
concentration less than 1 ppmv for each storage vessel vent; or (2) 
venting emissions through a closed-vent system to a flare meeting the 
operating and monitoring requirements for flares in NESHAP subpart F 
(see 40 CFR 63.119(a)(5), 40 CFR 63.108, and 40 CFR

[[Page 42936]]

63.124; and sections III.A.1 and IV.A of this preamble).\4\
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    \4\ See footnote 3.
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     a work practice standard to allow storage vessels to be 
vented to the atmosphere once a storage vessel degassing concentration 
threshold is met (i.e., once a storage vessel degassing organic HAP 
concentration of 5,000 ppmv as methane is met, or until the vapor space 
concentration is less than 10 percent of the LEL) and all standing 
liquid has been removed from the vessel to the extent practicable (see 
40 CFR 63.119(a)(6); and sections III.C and IV.C of this preamble).
     a definition for ``pressure vessel'' and removing the 
exemption for ``pressure vessels designed to operate in excess of 204.9 
kilopascals and without emissions to the atmosphere'' from the 
definition of storage vessel (see 40 CFR 63.101); and requirements for 
initial and annual performance testing of pressure vessels that are 
considered Group 1 storage vessels using EPA Method 21 of 40 CFR part 
60, appendix A-7 to demonstrate no detectable emissions (i.e., required 
to meet a leak definition of 500 parts per million (ppm) at each point 
on the pressure vessel where total organic HAP could potentially be 
emitted) (see 40 CFR 63.119(a)(7); and sections III.C and IV.C of this 
preamble).
     requirements that all openings in an internal floating 
roof (IFR) (except those for automatic bleeder vents (vacuum breaker 
vents), rim space vents, leg sleeves, and deck drains) be equipped with 
a deck cover; and that the deck cover be equipped with a gasket between 
the cover and the deck (see 40 CFR 63.119(b)(5)(ix); and sections 
III.B.1 and IV.B of this preamble).
     control requirements for guidepoles for all storage 
vessels equipped with an IFR (see 40 CFR 63.119(b)(5)(x), (xi), and 
(xii); and sections III.B.1 and IV.B of this preamble).
     a work practice standard that applies during periods of 
planned routine maintenance of a control device, fuel gas system, or 
process equipment that is normally used for compliance with the storage 
vessel emissions control requirements; owners and operators are not 
permitted to fill the storage vessel during these periods (such that 
working losses are controlled and the vessel only emits HAP to the 
atmosphere due to breathing losses for a limited amount of time) (see 
40 CFR 63.119(e)(7); and sections III.C and IV.C of this preamble).
     revisions to the Group 1 storage capacity criterion (for 
storage vessels at existing sources) from between 75 cubic meters 
(m\3\) and 151 m\3\ to between 38 m\3\ and 151 m\3\ (see Table 5 to 
subpart G; and sections III.B.1 and IV.B of this preamble).
     revisions to the Group 1 stored-liquid maximum true vapor 
pressure (MTVP) of total organic HAP threshold (for storage vessels at 
existing and new sources) from greater than or equal to 13.1 
kilopascals to greater than or equal to 6.9 kilopascals (see Tables 5 
and 6 to subpart G; and sections III.B.1 and IV.B of this preamble).
    For transfer racks, we are finalizing:
     removing the exemption for transfer operations that load 
``at an operating pressure greater than 204.9 kilopascals'' from the 
definition of transfer operation (see 40 CFR 63.101; and sections III.C 
and IV.C of this preamble).
    For wastewater streams, we are finalizing:
     revisions to the Group 1 wastewater stream threshold to 
include wastewater streams in EtO service (i.e., wastewater streams 
with total annual average concentration of EtO greater than or equal to 
1 parts per million by weight (ppmw) at any flow rate) (see 40 CFR 
63.132(c)(1)(iii) and (d)(1)(ii); and sections III.A and IV.A of this 
preamble).
     requirements prohibiting owners and operators from 
injecting wastewater into or disposing of water through any heat 
exchange system in a CMPU meeting the conditions of 40 CFR 63.100(b)(1) 
through (3) if the water contains any amount of EtO, has been in 
contact with any process stream containing EtO, or the water is 
considered wastewater as defined in 40 CFR 63.101 (see 40 CFR 
63.104(k); and sections III.A and IV.A of this preamble).
    For closed vent systems, we are finalizing:
     requirements that owners and operators may not bypass an 
air pollution control device (APCD) at any time (see 40 CFR 
63.114(d)(3), 40 CFR 63.127(d)(3), and 40 CFR 63.148(f)(4)), that a 
bypass is a violation, and that owners and operators must estimate and 
report the quantity of organic HAP released (see 40 CFR 63.118(a)(5), 
40 CFR 63.130(a)(2)(iv), 40 CFR 63.130(b)(3), 40 CFR 63.130(d)(7), and 
40 CFR 63.148(i)(3)(iii) and (j)(4); and sections III.C and IV.C of 
this preamble).
iii. NESHAP Subparts H and I
    As detailed in sections II.B.1.c and II.B.1.d of this preamble, 
NESHAP subparts H and I contain requirements for equipment leaks. Also, 
due to space limitations in NESHAP subpart F, we are finalizing 
fenceline monitoring (i.e., monitoring along the perimeter of the 
facility's property line) in NESHAP subpart H for all emission sources. 
For equipment leaks and fenceline monitoring, we are finalizing:
     requirements that all connectors in EtO service be 
monitored monthly at a leak definition of 100 ppm with no skip period, 
and delay of repair is not allowed unless the equipment can be isolated 
such that it is no longer in EtO service (see 40 CFR 63.174(a)(3), 
(b)(3)(vi), and (g)(3), and 40 CFR 63.171(f); and sections III.A and 
IV.A of this preamble).
     requirements that all gas/vapor and light liquid valves in 
EtO service be monitored monthly at a leak definition of 100 ppm with 
no skip period, and delay of repair is not allowed unless the equipment 
can be isolated such that it is no longer in EtO service (see 40 CFR 
63.168(b)(2)(iv) and (d)(5), and 40 CFR 63.171(f); and sections III.A 
and IV.A of this preamble).
     requirements that all light liquid pumps in EtO service be 
monitored monthly at a leak definition of 500 ppm, and delay of repair 
is not allowed unless the equipment can be isolated such that it is no 
longer in EtO service (see 40 CFR 63.163(a)(1)(iii), (b)(2)(iv), 
(c)(4), and (e)(7), and 40 CFR 63.171(f); and sections III.A and IV.A 
of this preamble).
     a work practice standard for pressure relief devices 
(PRDs) that vent to the atmosphere that require owners and operators to 
implement at least three prevention measures, perform root cause 
analysis and corrective action in the event that a PRD does release 
emissions directly to the atmosphere, and monitor PRDs using a system 
that is capable of identifying and recording the time and duration of 
each pressure release and of notifying operators that a pressure 
release has occurred (see 40 CFR 63.165(e); and sections III.C and IV.C 
of this preamble).
     requirements that all surge control vessels and bottoms 
receivers meet the requirements we are finalizing for process vents 
(see 40 CFR 63.170(b); and sections III.C and IV.C of this preamble).
     requirements that owners and operators may not bypass an 
APCD at any time (see 40 CFR 63.114(d)(3), 40 CFR 63.127(d)(3), and 40 
CFR 63.148(f)(4)), that a bypass is a violation, and that owners and 
operators must estimate and report the quantity of organic HAP released 
(see 40 CFR 63.118(a)(5), 40 CFR 63.130(a)(2)(iv), 40 CFR 63.130(b)(3), 
40 CFR 63.130(d)(7), and 40 CFR 63.148(i)(3)(iii) and (j)(4); and 
sections III.C and IV.C of this preamble).
     fenceline monitoring work practice standards requiring 
owners and operators to monitor for any of six

[[Page 42937]]

specific HAP (i.e., benzene, 1,3-butadiene, ethylene dichloride, vinyl 
chloride, EtO, and chloroprene) if their affected source uses, 
produces, stores, or emits any of them, and conduct root cause analysis 
and corrective action upon exceeding annual average concentration 
action levels set forth for each HAP (see 40 CFR 63.184; and sections 
III.B.1 and IV.B of this preamble).
b. P&R I NESHAP
    As detailed in section II.B.2 of this preamble, the P&R I NESHAP 
(40 CFR part 63, subpart U) generally follows and refers to the 
requirements of the HON, with additional requirements for batch process 
vents. We are finalizing amendments to the P&R I NESHAP for heat 
exchange systems, process vents, storage vessels, wastewater, and 
equipment leaks. For NESHAP subpart U, we are finalizing:
     compliance dates for all of the requirements in this 
action related to the P&R I NESHAP (see 40 CFR 63.481(n) and (o); and 
section III.G of this preamble).
     new operating and monitoring requirements for flares (see 
40 CFR 63.508; and sections III.C and IV.C of this preamble).
     the removal of the provisions to assert an affirmative 
defense to civil penalties (see 40 CFR 63.480(j)(4); and sections III.D 
and IV.D of this preamble).
     the same fenceline monitoring requirements that we are 
finalizing in Subpart H for HON sources.
     sampling and analysis procedures for owners and operators 
of affected sources producing neoprene to demonstrate that process 
equipment does, or does not, meet the definition of being ``in 
chloroprene service'' (see 40 CFR 63.509; and sections III.A and IV.A 
of this preamble).
    For heat exchange systems, we are finalizing:
     the same requirements (except for EtO standards) listed in 
section I.A.2.a.i of this preamble that we are finalizing for heat 
exchange systems subject to the HON to also apply to heat exchange 
systems subject to the P&R I NESHAP (see 40 CFR 63.502(n)(7); and 
sections III.B.1 and IV.B of this preamble).
    For continuous front-end process vents, we are finalizing:
     the requirement that owners and operators must reduce 
emissions of chloroprene from continuous front-end process vents in 
chloroprene service at affected sources producing neoprene by venting 
emissions through a closed-vent system to a non-flare control device 
that reduces chloroprene by greater than or equal to 98 percent by 
weight, to a concentration less than 1 ppmv for each process vent, or 
to less than 5 lb/yr for all combined process vents per elastomer 
product process unit (EPPU) (see 40 CFR 63.485(y), and 40 CFR 63.510; 
and sections III.A and IV.A of this preamble).\5\
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    \5\ We are also removing the option to allow use of a design 
evaluation in lieu of performance testing to demonstrate compliance 
for controlling various emission sources in chloroprene service. In 
addition, owners or operators are required to conduct an initial 
performance test on each non-flare control device in chloroprene 
service to verify performance at the required level of control, and 
are required to conduct periodic performance testing on non-flare 
control devices in chloroprene service every 5 years (see 40 CFR 
63.510).
---------------------------------------------------------------------------

     the same requirements (except for EtO standards) listed in 
section I.A.2.a.ii of this preamble that we are finalizing for process 
vents subject to the HON to also apply to continuous front-end process 
vents subject to the P&R I NESHAP (see 40 CFR 63.482, 40 CFR 
63.485(l)(6), (o)(6), (p)(5), and (x), 40 CFR 63.113(a)(1) and (2), 40 
CFR 63.113(a)(4), 40 CFR 63.113(k), 40 CFR 63.114(a)(5)(v); and 
sections III.B.1 and IV.B of this preamble).
     requirements that owners and operators of continuous 
front-end process vents in chloroprene service are allowed to use the 
maintenance vent work practice standards; however, owners and operators 
are prohibited from releasing more than 1.0 ton of chloroprene from all 
maintenance vents combined on a facility basis in any consecutive 12-
month period (see 40 CFR 63.485(z); and sections III.A and IV.A of this 
preamble).
     the same dioxins and furans emission standard that we are 
finalizing for process vents subject to the HON of 0.054 ng/dscm at 3 
percent oxygen (toxic equivalency basis) to also apply to chlorinated 
continuous front-end process vents (see 40 CFR 63.485(x); and sections 
III.C and IV.C of this preamble).
    For batch front-end process vents, we are finalizing:
     the removal of the annual organic HAP emissions mass flow 
rate, cutoff flow rate, and annual average batch vent flow rate Group 1 
process vent thresholds from the Group 1 batch front-end process vent 
definition (these thresholds were previously determined on an 
individual batch process vent basis). Instead, owners and operators of 
batch front-end process vents that release total annual organic HAP 
emissions greater than or equal to 4,536 kilograms per year (kg/yr) 
(10,000 pounds per year (lb/yr)) from all batch front-end process vents 
combined are required to reduce emissions of organic HAP from these 
process vents using a flare meeting the operating and monitoring 
requirements for flares; or reduce emissions of organic HAP or total 
organic carbon (TOC) by 90 percent by weight (or to an exit 
concentration of 20 ppmv if considered an ``aggregate batch vent 
stream'' as defined by the rule) (see 40 CFR 63.482, 40 CFR 
63.487(e)(1)(iv), 40 CFR 63.488(d)(2), (e)(4), (f)(2), and (g)(3); and 
sections III.B.1 and IV.B of this preamble).
     the same chloroprene standards that we are finalizing for 
continuous front-end process for batch front-end process vents at 
affected sources producing neoprene (see 40 CFR 63.487(j); and sections 
III.A and IV.A of this preamble).
     the same work practice standards that we are finalizing 
for maintenance vents as described for HON to the P&R I NESHAP (see 40 
CFR 63.487(i); and sections III.C and IV.C of this preamble).
     requirements that owners and operators of batch front-end 
process vents in chloroprene service are allowed to use the maintenance 
vent work practice standards; however, owners and operators are 
prohibited from releasing more than 1.0 ton of chloroprene from all 
maintenance vents combined on a facility basis in any consecutive 12-
month period (see 40 CFR 63.487(i)(4); and sections III.A and IV.A of 
this preamble).
     the same dioxins and furans emission standard that we are 
finalizing for process vents subject to the HON of 0.054 ng/dscm at 3 
percent oxygen (toxic equivalency basis) to also apply to chlorinated 
batch front-end process vents (see 40 CFR 63.487(a)(3) and (b)(3); and 
sections III.C and IV.C of this preamble).
    For back-end process vents, we are finalizing:
     a requirement that owners and operators reduce emissions 
of chloroprene from back-end process vents in chloroprene service at 
affected sources producing neoprene by venting emissions through a 
closed-vent system to a non-flare control device that reduces 
chloroprene by greater than or equal to 98 percent by weight, to a 
concentration less than 1 ppmv for each process vent, or to less than 5 
lb/yr for all combined process vents (see 40 CFR 63.494(a)(7); and 
sections III.A and IV.A of this preamble).
    For storage vessels, we are finalizing:
     the requirement that owners and operators reduce emissions 
of chloroprene from storage vessels in chloroprene service at affected 
sources producing neoprene by venting emissions through a closed-vent 
system to a non-flare control device that reduces chloroprene by 
greater than or equal to 98 percent by weight or to a

[[Page 42938]]

concentration less than 1 ppmv for each storage vessel vent (see 40 CFR 
63.484(u) and 40 CFR 63.510; and sections III.A and IV.A of this 
preamble).\6\
---------------------------------------------------------------------------

    \6\ See footnote 5.
---------------------------------------------------------------------------

     the same requirements (except for EtO standards) listed in 
section I.A.2.a.ii of this preamble that we are finalizing for storage 
vessels subject to the HON except the requirements apply to storage 
vessels subject to the P&R I NESHAP (see 40 CFR 63.484(t); and sections 
III.B.1 and IV.B of this preamble).
    For wastewater streams, we are finalizing:
     the Group 1 wastewater stream threshold to include 
wastewater streams in chloroprene service at affected sources producing 
neoprene (i.e., wastewater streams with total annual average 
concentration of chloroprene greater than or equal to 10 ppmw at any 
flow rate) (see 40 CFR 63.501(a)(10)(iv); and sections III.A and IV.A 
of this preamble).
     requirements prohibiting owners and operators from 
injecting wastewater into or disposing of water through any heat 
exchange system in an EPPU if the water contains any amount of 
chloroprene, has been in contact with any process stream containing 
chloroprene, or the water is considered wastewater as defined in 40 CFR 
63.482 (see 40 CFR 63.502(n)(8); and sections III.A and IV.A of this 
preamble).
    For equipment leaks and fenceline monitoring, we are finalizing:
     the same requirements (except for EtO standards) listed in 
section I.A.2.a.iii of this preamble that we are finalizing for 
equipment leaks subject to the HON except the requirements apply to 
equipment leaks subject to the P&R I NESHAP (see 40 CFR 63.502(a)(1) 
through (a)(6); and sections III.C and IV.C of this preamble).
     the cross-reference in the P&R I NESHAP to the fenceline 
monitoring work practice standards in the HON (see 40 CFR 63.502) 
requiring owners and operators to monitor for any of six specific HAP 
(i.e., benzene, 1,3-butadiene, ethylene dichloride, vinyl chloride, 
EtO, and chloroprene) if their affected source uses, produces, stores, 
or emits any of them, and conduct root cause analysis and corrective 
action upon exceeding annual average concentration action levels set 
forth for each HAP (see sections III.B.1 and IV.B of this preamble), 
plus a lower annual average concentration action level for chloroprene 
applicable to neoprene production source category (see sections III.A 
and IV.A of this preamble).
c. P&R II NESHAP
    The most significant amendments that we are finalizing for the P&R 
II NESHAP (40 CFR part 63, subpart W) are requirements for heat 
exchange systems (see 40 CFR 63.523(d) and 40 CFR 63.524(c); and 
sections III.C and IV.C of this preamble) and requirements for owners 
and operators of wet strength resins (WSR) sources to comply with both 
the equipment leak standards in the HON and the HAP emissions 
limitation for process vents, storage tanks, and wastewater systems 
(see 40 CFR 63.524(a)(3) and (b)(3); and sections III.C and IV.C of 
this preamble). We are also finalizing the same dioxin and furan 
emission standard of 0.054 ng/dscm at 3 percent oxygen (toxic 
equivalency basis) for chlorinated process vents as in the HON and the 
P&R I NESHAP (see 40 CFR 63.523(e) (for process vents associated with 
each existing, new, or reconstructed affected basic liquid epoxy resins 
(BLR) source), 40 CFR 63.524(a)(3) (for process vents associated with 
each existing affected WSR source), and 40 CFR 63.524(b)(3) (for 
process vents associated with each new or reconstructed affected WSR 
source); and see sections III.C and IV.C of this preamble).
d. NSPS Subparts III, NNN, and RRR
    We are amending the applicability of NSPS subparts III, NNN, and 
RRR so that they only apply to sources constructed, reconstructed, or 
modified on or before April 25, 2023. Affected facilities that are 
constructed, reconstructed, or modified after April 25, 2023, are 
subject to the new NSPS subparts IIIa, NNNa, and RRRa.
e. NSPS Subparts IIIa, NNNa, and RRRa
    Rather than comply with a TRE concept which is used in NSPS 
subparts III, NNN, and RRR, we are finalizing in new NSPS subparts 
IIIa, NNNa, and RRRa a requirement for owners and operators to reduce 
emissions of TOC (minus methane and ethane) from all vent streams of an 
affected facility (i.e., SOCMI air oxidation unit processes, 
distillation operations, and reactor processes for which construction, 
reconstruction, or modification occurs after April 25, 2023) by 98 
percent by weight or to a concentration of 20 ppmv on a dry basis 
corrected to 3 percent oxygen, or combust the emissions in a flare 
meeting the same operating and monitoring requirements for flares that 
we are finalizing for flares subject to the HON. We are finalizing a 
mass-based exemption criterion of 0.001 lb/hr TOC (for which emission 
controls are not required) in new NSPS subparts IIIa and NNNa. We are 
also not including a relief valve discharge exemption in the definition 
of ``vent stream'' in new NSPS subparts IIIa, NNNa, and RRRa; instead, 
any relief valve discharge to the atmosphere of a vent stream is a 
violation of the emissions standard. In addition, we are finalizing in 
new NSPS subparts IIIa, NNNa, and RRRa the same work practice standards 
for maintenance vents that we are finalizing for HON process vents, and 
the same monitoring requirements that we are finalizing for HON process 
vents for adsorbers that cannot be regenerated and regenerative 
adsorbers that are regenerated offsite (see sections III.B.2 and IV.B 
of this preamble).
f. NSPS Subpart VVa
    We are amending certain aspects of NSPS subparts VV and VVa to 
address issues raised in an administrative petition which the Agency 
granted pursuant to section 307(d)(7)(B) of the CAA. In addition, we 
are amending the applicability of the existing NSPS subpart VVa so that 
it applies to sources constructed, reconstructed, or modified after 
November 6, 2006, and on or before April 25, 2023. Affected facilities 
that are constructed, reconstructed, or modified after April 25, 2023, 
are subject to the new NSPS subpart VVb.
g. NSPS Subpart VVb
    We are finalizing in a new NSPS subpart VVb the same requirements 
in NSPS subpart VVa plus a requirement that all gas/vapor and light 
liquid valves be monitored quarterly at a leak definition of 100 ppm 
and all connectors be monitored once every 12 months at a leak 
definition of 500 ppm (see sections III.B.2 and IV.B of this preamble). 
For each of these two additional requirements, we are also finalizing 
skip periods for good performance.
3. Costs and Benefits
    Pursuant to E.O. 12866, the EPA prepared an analysis of the 
potential costs and benefits associated with this action. This 
analysis, titled Regulatory Impact Analysis for the Final New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry (referred to as the RIA in this 
document), is available in the docket, and is also briefly summarized 
in section V of this preamble. The assessment of costs and benefits 
described herein and in the RIA is

[[Page 42939]]

presented solely for the purposes of complying with E.O. 12866 and to 
provide the public with a complete depiction of the impacts of this 
final action. The EPA notes that analysis of costs and benefits in the 
RIA is distinct from the determinations finalized in this action under 
CAA sections 111 and 112, which are based on the statutory factors the 
EPA is required to consider under those sections.

B. Does this action apply to me?

    Regulated entities. Categories and entities potentially regulated 
by this action are the SOCMI source category (and whose facilities, 
sources and processes we often refer to as ``HON facilities,'' ``HON 
sources,'' and ``HON processes'' for purposes of the NESHAP) and 
several Polymers and Resins Production source categories covered in the 
P&R I and P&R II NESHAP (see section II.B of this preamble for detailed 
information about the source categories).\7\ The North American 
Industry Classification System (NAICS) code for SOCMI facilities begins 
with 325, for P&R I facilities is 325212, and for P&R II facilities is 
325211. The list of NAICS codes is not intended to be exhaustive, but 
rather provides a guide for readers regarding the entities that this 
final action is likely to affect.
---------------------------------------------------------------------------

    \7\ The P&R I NESHAP includes MACT standards for nine listed 
elastomer production source categories (i.e., Butyl Rubber 
Production, Epichlorohydrin Elastomers Production, Ethylene-
Propylene Elastomers Production, HypalonTM Production, 
Neoprene Production, Nitrile Butadiene Rubber Production, 
Polybutadiene Rubber Production, Polysulfide Rubber Production, and 
Styrene-Butadiene Rubber and Latex Production). The P&R II NESHAP 
includes MACT standards for two listed source categories that use 
epichlorohydrin feedstock (Epoxy Resins Production and Non-Nylon 
Polyamides Production).
---------------------------------------------------------------------------

    As defined in the Initial List of Categories of Sources Under 
Section 112(c)(1) of the Clean Air Act Amendments of 1990 (see 57 FR 
31576, July 16, 1992) and Documentation for Developing the Initial 
Source Category List, Final Report (see EPA-450/3-91-030, July 1992), 
the SOCMI source category is any facility engaged in ``manufacturing 
processes that produce one or more of the chemicals [listed] that 
either: (1) Use an organic HAP as a reactant or (2) produce an organic 
HAP as a product, co-product, by-product, or isolated intermediate.'' 
\8\ In the development of NESHAP for this source category, the EPA 
considered emission sources associated with: equipment leaks (including 
leaks from heat exchange systems), process vents, transfer racks, 
storage vessels, and wastewater collection and treatment systems. The 
elastomer production source categories in the P&R I NESHAP and resins 
produced with epichlorohydrin feedstock in the P&R II NESHAP have many 
similar emission sources with SOCMI sources and are discussed further 
in section II.B of this preamble.
---------------------------------------------------------------------------

    \8\ The original list of chemicals is located in Appendix A 
(beginning on page A-71) of EPA-450/3-91-030 dated July 1992. 
Alternatively, the most recent list of chemicals is documented in 
the HON applicability rule text at 40 CFR 63.100(b)(1) and (2). The 
original list of organic HAPs for the SOCMI source category is 
located in Table 3.1 of Section 3.0 of EPA-450/3-91-030.
---------------------------------------------------------------------------

    The EPA Priority List (40 CFR 60.16, 44 FR 49222, August 21, 1979) 
included ``Synthetic Organic Chemical Manufacturing'' \9\ as a source 
category for which standards of performance were to be promulgated 
under CAA section 111. In the development of NSPS subparts VVa, III, 
NNN, and RRR for this source category, the EPA considered emission 
sources associated with unit processes, storage and handling equipment, 
fugitive emission sources, and secondary sources.
---------------------------------------------------------------------------

    \9\ For readability, we also refer to this as the SOCMI source 
category for purposes of the NSPS.
---------------------------------------------------------------------------

    To determine whether your facility is affected, you should examine 
the applicability criteria in the appropriate NESHAP or NSPS. If you 
have any questions regarding the applicability of any aspect of these 
NESHAP and NSPS, please contact the appropriate person listed in the 
preceding FOR FURTHER INFORMATION CONTACT section of this preamble.

C. Where can I get a copy of this document and other related 
information?

    In addition to being available in the docket, an electronic copy of 
this final action will also be available on the internet. Following 
signature by the EPA Administrator, the EPA will post a copy of this 
final action at: https://www.epa.gov/stationary-sources-air-pollution/synthetic-organic-chemical-manufacturing-industry-organic-national, 
https://www.epa.gov/stationary-sources-air-pollution/group-i-polymers-and-resins-national-emission-standards-hazardous, and https://www.epa.gov/stationary-sources-air-pollution/epoxy-resins-production-and-non-nylon-polyamides-national-emission. Following publication in 
the Federal Register, the EPA will post the Federal Register version 
and key technical documents at these same websites.
    Additional information is available on the RTR website at https://www.epa.gov/stationary-sources-air-pollution/risk-and-technology-review-national-emissions-standards-hazardous. This information 
includes an overview of the RTR program and links to project websites 
for the RTR source categories.

D. Judicial Review and Administrative Reconsideration

    Under CAA section 307(b)(1), judicial review of this final action 
is available only by filing a petition for review in the United States 
Court of Appeals for the District of Columbia Circuit (the Court) by 
July 15, 2024. Under CAA section 307(b)(2), the requirements 
established by these final rules may not be challenged separately in 
any civil or criminal proceedings brought to enforce the requirements.
    Section 307(d)(7)(B) of the CAA further provides that only an 
objection to a rule or procedure which was raised with reasonable 
specificity during the period for public comment (including any public 
hearing) may be raised during judicial review. This section also 
provides a mechanism for the EPA to reconsider the rule if the person 
raising an objection can demonstrate to the Administrator that it was 
impracticable to raise such objection within the period for public 
comment or if the grounds for such objection arose after the period for 
public comment (but within the time specified for judicial review) and 
if such objection is of central relevance to the outcome of the rule. 
Any person seeking to make such a demonstration should submit a 
Petition for Reconsideration to the Office of the Administrator, U.S. 
EPA, Room 3000, WJC South Building, 1200 Pennsylvania Ave. NW, 
Washington, DC 20460, with a copy to both the person(s) listed in the 
preceding FOR FURTHER INFORMATION CONTACT section, and the Associate 
General Counsel for the Air and Radiation Law Office, Office of General 
Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania Ave. NW, 
Washington, DC 20460.

II. Background

A. What is the statutory authority for this action?

1. NESHAP
    The statutory authority for this action related to NESHAP is 
provided by sections 112 and 301 of the CAA, as amended (42 U.S.C. 7401 
et seq.). Section 112 of the CAA establishes a two-stage regulatory 
process to develop standards for emissions of HAP from stationary 
sources. ``Major sources'' are those that emit, or have the potential 
to emit, any single HAP at a rate of 10 tpy or more, or 25 tpy or more 
of any combination of HAP. For major sources,

[[Page 42940]]

these standards are commonly referred to as MACT standards and must 
reflect the maximum degree of emission reductions of HAP achievable 
(after considering cost, energy requirements, and non-air quality 
health and environmental impacts). In developing MACT standards, CAA 
section 112(d)(2) directs the EPA to consider the application of 
measures, processes, methods, systems, or techniques, including, but 
not limited to, those that reduce the volume of or eliminate HAP 
emissions through process changes, substitution of materials, or other 
modifications; enclose systems or processes to eliminate emissions; 
collect, capture, or treat HAP when released from a process, stack, 
storage, or fugitive emissions point; are design, equipment, work 
practice, or operational standards; or any combination of the above. 
The MACT standards may take the form of design, equipment, work 
practice or operational standards where the EPA first determines either 
that (1) a pollutant cannot be emitted through a conveyance designed 
and constructed to emit or capture the pollutant, or that any 
requirement for, or use of, such a conveyance would be inconsistent 
with law; or (2) the application of measurement methodology to a 
particular class of sources is not practicable due to technological and 
economic limitations. CAA section 112(h)(1)-(2).
    For these MACT standards, the statute specifies certain minimum 
stringency requirements, which are referred to as MACT floor 
requirements, and which may not be based on cost considerations. See 
CAA section 112(d)(3). For new sources, the MACT floor cannot be less 
stringent than the emission control achieved in practice by the best-
controlled similar source. The MACT standards for existing sources can 
be less stringent than floors for new sources, but they cannot be less 
stringent than the average emission limitation achieved by the best-
performing 12 percent of existing sources in the category or 
subcategory (or the best-performing five sources for categories or 
subcategories with fewer than 30 sources). In developing MACT 
standards, we must also consider control options that are more 
stringent than the floor under CAA section 112(d)(2). We may establish 
standards more stringent than the floor, based on the consideration of 
the cost of achieving the emissions reductions, any non-air quality 
health and environmental impacts, and energy requirements.
    In the second stage of the regulatory process, the CAA requires the 
EPA to undertake two different analyses, which we refer to as the 
technology review and the residual risk review. Under the technology 
review, we must review the technology-based standards and revise them 
``as necessary (taking into account developments in practices, 
processes, and control technologies)'' no less frequently than every 8 
years, pursuant to CAA section 112(d)(6). In conducting this review, 
the EPA is not required to recalculate the MACT floors that were 
established in earlier rulemakings. Natural Resources Defense Council 
(NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008); Association of 
Battery Recyclers, Inc. v. EPA, 716 F.3d 667 (D.C. Cir. 2013). The EPA 
may consider cost in deciding whether to revise the standards pursuant 
to CAA section 112(d)(6). The EPA is required to address regulatory 
gaps, such as missing standards for listed air toxics known to be 
emitted from the source category, and any new MACT standards must be 
established under CAA sections 112(d)(2) and (3), or, in specific 
circumstances, CAA sections 112(d)(4) or (h). Louisiana Environmental 
Action Network v. EPA, 955 F.3d 1088 (D.C. Cir. 2020). Under the 
residual risk review, we must evaluate the risk to public health 
remaining after application of the technology-based standards and 
revise the standards, if necessary, to provide an ample margin of 
safety to protect public health or to prevent, taking into 
consideration costs, energy, safety, and other relevant factors, an 
adverse environmental effect. The residual risk review is required 
within 8 years after promulgation of the MACT standards, pursuant to 
CAA section 112(f). In conducting the residual risk review, if the EPA 
determines that the current standards provide an ample margin of safety 
to protect public health, it is not necessary to revise the MACT 
standards pursuant to CAA section 112(f).\10\ For more information on 
the statutory authority for this rule, see 88 FR 25080, April 25, 2023. 
Often, the CAA section 112(d)(6) technology review and the CAA section 
112(f)(2) residual risk review are combined into a single rulemaking 
action, commonly called a ``risk and technology review'' (RTR).
---------------------------------------------------------------------------

    \10\ The Court has affirmed this approach of implementing CAA 
section 112(f)(2)(A): NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 
2008) (``If EPA determines that the existing technology-based 
standards provide an 'ample margin of safety,' then the Agency is 
free to readopt those standards during the residual risk 
rulemaking.'').
---------------------------------------------------------------------------

    The EPA conducted a combined RTR for the HON in 2006, concluding 
that there was no need to revise the HON under the provisions of either 
CAA section 112(f) or 112(d)(6). As part of the residual risk review, 
the EPA conducted a risk assessment and, based on the results of the 
risk assessment, determined that the then-current level of control 
called for by the existing MACT standards both reduced HAP emissions to 
levels that presented an acceptable level of risk and provided an ample 
margin of safety to protect public health (see 71 FR 76603, December 
21, 2006 for additional details). In 2008, the EPA conducted a combined 
RTR for four of the P&R I source categories (including the Polysulfide 
Rubber Production, Ethylene-Propylene Elastomers Production, Butyl 
Rubber Production, and Neoprene Production source categories) and all 
P&R II source categories (Epoxy Resins Production and Non-Nylon 
Polyamides Production source categories). In 2011, the EPA completed 
the combined RTR for the remaining five P&R I source categories 
(Epichlorohydrin Elastomers Production, Hypalon\TM\ Production, 
Polybutadiene Rubber Production, Styrene-Butadiene Rubber and Latex 
Production, and Nitrile Butadiene Rubber Production). The EPA concluded 
in these actions that there was no need to revise standards for any of 
the nine P&R I source categories and two P&R II source categories under 
the provisions of either CAA section 112(f) or 112(d)(6) (see 73 FR 
76220, December 16, 2008 and 77 FR 22566, April 21, 2011 for additional 
details).\11\
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    \11\ We note that in the April 21, 2011, rulemaking (see 77 FR 
22566), the EPA finalized amendments to eliminate the SSM exemption 
in the P&R I NESHAP; however, for consistency with the SSM related 
amendments that we are finalizing for the HON and the P&R II NESHAP, 
we are also finalizing (as detailed in section IV.D of this 
preamble) additional amendments to the P&R I NESHAP related to the 
SSM exemption that were not addressed in the April 21, 2011, P&R I 
rule.
---------------------------------------------------------------------------

    This action constitutes another CAA section 112(d)(6) technology 
review for the HON and the P&R I and P&R II NESHAP. This action also 
constitutes an updated CAA section 112(f) risk review based on new 
information for the HON and for affected sources producing neoprene 
subject to the P&R I NESHAP. We note that although there is no 
statutory CAA obligation under CAA section 112(f) for the EPA to 
conduct a second residual risk review of the HON or of standards for 
affected sources producing neoprene subject to the P&R I NESHAP, the 
EPA retains discretion to revisit its residual risk reviews where the 
Agency deems that to be warranted. See, e.g., Fed. Commc'ns Comm'n v. 
Fox Television Stations, Inc., 556 U.S. 502,

[[Page 42941]]

515 (2009); Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins. 
Co., 463 U.S. 29, 42 (1983); Ethylene Oxide Emissions Standards for 
Sterilization Facilities; Final Decision, 71 FR 17712, 17715 col. 1 
(April 7, 2006) (asserting authority, in residual risk review for EtO, 
for EPA ``to revisit (and revise, if necessary) any rulemaking if there 
is sufficient evidence that changes within the affected industry or 
significant improvements to science suggests the public is exposed to 
significant increases in risk as compared to the risk assessment 
prepared for the rulemaking (e.g., CAA section 301).'').
    Here, the specific changes to health information related to certain 
pollutants emitted by these unique categories led us to determine that 
it is appropriate, in this case, to conduct these second residual risk 
reviews under CAA section 112(f). In particular, the EPA is concerned 
about the cancer risks posed by the SOCMI source category due to the 
EPA's 2016 updated IRIS inhalation URE for EtO, which shows EtO to be 
significantly more toxic than previously known.\12\ This updated URE 
was not available in 2006, when the EPA conducted its last RTR, but if 
this URE had been available, the EPA would almost undoubtedly have 
reached different conclusions about risk acceptability and the need to 
modify the standards to provide an ample margin of safety to protect 
public health. Similarly, for chloroprene, when the EPA conducted the 
first residual risk assessment for the SOCMI and Neoprene Production 
source categories, there was no inhalation URE for chloroprene. 
Therefore, in those risk reviews, the EPA attributed no cancer risk to 
chloroprene. The EPA concluded development of the IRIS inhalation URE 
for chloroprene in 2010. That URE allows us to assess, for the first 
time, the cancer risks posed by chloroprene. Had the EPA had the 
benefit of this new URE at the time it conducted the 2006 and 2008 
RTRs, the URE would almost undoubtedly have impacted our conclusions 
about risk acceptability and the P&R I standards' provision of an ample 
margin of safety to protect public health. Instead, we are conducting 
that analysis in this action.
---------------------------------------------------------------------------

    \12\ U.S. EPA. Evaluation of the Inhalation Carcinogenicity of 
Ethylene Oxide (CASRN 75-21-8) In Support of Summary Information on 
the Integrated Risk Information System (IRIS). December 2016. EPA/
635/R-16/350Fa. Available at: https://cfpub.epa.gov/ncea/iris/iris_documents/documents/toxreviews/1025tr.pdf. See also, 87 FR 
77985 (Dec. 21, 2022), Reconsideration of the 2020 National Emission 
Standards for Hazardous Air Pollutants: Miscellaneous Organic 
Chemical Manufacturing Residual Risk and Technology Review, Final 
action; reconsideration of the final rule.
---------------------------------------------------------------------------

    In order to ensure our standards provide an ample margin of safety 
to protect public health following the new IRIS inhalation UREs for EtO 
and chloroprene, we are exercising our discretion and conducting risk 
assessments in this action for HON sources and for affected sources 
producing neoprene subject to the P&R I NESHAP. Finally, we note that 
on September 15, 2021, the EPA partially granted a citizen 
administrative petition requesting that the EPA conduct a second 
residual risk review under CAA section 112(f)(2) for the HON, stating 
our intent to conduct a human health risk assessment concurrently with 
the section 112(d)(6) review.\13\ Likewise, on March 4, 2022, the EPA 
partially granted another citizen administrative petition requesting 
that the EPA also conduct a second residual risk review under CAA 
section 112(f) for the Neoprene Production source category in the P&R I 
NESHAP, stating that we intend to conduct a human health risk 
assessment concurrently with the section 112(d)(6) review.\14\ This 
final rulemaking is partly undertaken in response to those citizen 
administrative petitions. In sum, even though we do not have a 
mandatory duty to conduct repeated residual risk reviews under CAA 
section 112(f)(2), we have the authority to revisit any rulemaking if 
there is: (1) Significant new scientific information suggesting the 
public is exposed to higher risks from facilities subject to the HON 
and the P&R I and P&R II NESHAP than previously realized, as compared 
to the previous risk assessments prepared for earlier rulemakings, or 
(2) sufficient evidence that changes within the affected industry are 
exposing the public to new risks.
---------------------------------------------------------------------------

    \13\ See letter dated September 15, 2021, from Joseph Goffman to 
Kathleen Riley, Emma Cheuse, and Adam Kron (see Docket Item No. EPA-
HQ-OAR-2022-0730-0047).
    \14\ See letter dated March 4, 2022, from Joseph Goffman to Emma 
Cheuse, Deena Tumeh, Michelle Mabson, Maryum Jordan, and Dorian 
Spence (see Docket Item No. EPA-HQ-OAR-2022-0730-0048).
---------------------------------------------------------------------------

2. NSPS
    The EPA's authority for the final NSPS rules is CAA section 111, 
which governs the establishment of standards of performance for 
stationary sources. Section 111(b)(1)(A) of the CAA requires the EPA 
Administrator to list categories of stationary sources that in the 
Administrator's judgment cause or contribute significantly to air 
pollution that may reasonably be anticipated to endanger public health 
or welfare. The EPA must then issue performance standards for new (and 
modified or reconstructed) sources in each source category pursuant to 
CAA section 111(b)(1)(B). These standards are referred to as new source 
performance standards, or NSPS. The EPA has the authority to define the 
scope of the source categories, determine the pollutants for which 
standards should be developed, set the emission level of the standards, 
and distinguish among classes, types, and sizes within categories in 
establishing the standards.
    CAA section 111(b)(1)(B) requires the EPA to ``at least every 8 
years review and, if appropriate, revise'' NSPS. However, the 
Administrator need not review any such standard if the ``Administrator 
determines that such review is not appropriate in light of readily 
available information on the efficacy'' of the standard. When 
conducting a review of an existing performance standard, the EPA has 
the discretion and authority to add emission limits for pollutants or 
emission sources not currently regulated for that source category.
    In setting or revising a performance standard, CAA section 
111(a)(1) provides that performance standards are to reflect ``the 
degree of emission limitation achievable through the application of the 
BSER which (taking into account the cost of achieving such reduction 
and any nonair quality health and environmental impact and energy 
requirements) the Administrator determines has been adequately 
demonstrated.'' The term ``standard of performance'' in CAA section 
111(a)(1) makes clear that the EPA is to determine both the BSER for 
the regulated sources in the source category and the degree of emission 
limitation achievable through application of the BSER. The EPA must 
then, under CAA section 111(b)(1)(B), promulgate standards of 
performance for new sources that reflect that level of stringency. CAA 
section 111(h)(1) authorizes the Administrator to promulgate ``a 
design, equipment, work practice, or operational standard, or 
combination thereof'' if in his or her judgment, ``it is not feasible 
to prescribe or enforce a standard of performance.'' CAA section 
111(h)(2) provides the circumstances under which prescribing or 
enforcing a standard of performance is ``not feasible,'' such as, when 
the pollutant cannot be emitted through a conveyance designed to emit 
or capture the pollutant, or when there is no practicable measurement 
methodology for the particular class of sources. CAA section 111(b)(5) 
precludes the EPA from prescribing a particular technological system 
that must be used

[[Page 42942]]

to comply with a standard of performance. Rather, sources can select 
any measure or combination of measures that will achieve the standard.
    Pursuant to the definition of new source in CAA section 111(a)(2), 
standards of performance apply to facilities that begin construction, 
reconstruction, or modification after the date of publication of the 
proposed standards in the Federal Register. Under CAA section 
111(a)(4), ``modification'' means any physical change in, or change in 
the method of operation of, a stationary source which increases the 
amount of any air pollutant emitted by such source or which results in 
the emission of any air pollutant not previously emitted. Changes to an 
existing facility that do not result in an increase in emissions are 
not considered modifications. Under the provisions in 40 CFR 60.15, 
reconstruction means the replacement of components of an existing 
facility such that: (1) The fixed capital cost of the new components 
exceeds 50 percent of the fixed capital cost that would be required to 
construct a comparable entirely new facility; and (2) it is 
technologically and economically feasible to meet the applicable 
standards.
    In the development of NSPS for the SOCMI source category, the EPA 
considered emission sources associated with unit processes, storage and 
handling equipment, fugitive emission sources, and secondary sources. 
In 1983, the EPA promulgated NSPS for VOC from equipment leaks in SOCMI 
(40 CFR part 60, subpart VV). In 1990, the EPA promulgated NSPS (40 CFR 
part 60, subparts III and NNN) for VOC from air oxidation unit 
processes and distillation operations in the SOCMI (55 FR 26912 and 55 
FR 26931). In 1993, the EPA promulgated NSPS (40 CFR part 60, subpart 
RRR) for VOC from reactor processes in the SOCMI (58 FR 45948). In 
2007, based on its review of NSPS subpart VV, the EPA promulgated 
certain amendments to NSPS subpart VV and new NSPS (40 CFR part 60, 
subpart VVa) for VOC from certain equipment leaks in the SOCMI (72 FR 
64883). This final action presents the required CAA 111(b)(1)(B) review 
of the NSPS for the air oxidation unit processes (subpart III), 
distillation operations (subpart NNN), reactor processes (subpart RRR), 
and equipment leaks (subpart VVa).
3. Petition for Reconsideration
    In addition to the final action under CAA section 111(b)(1)(B) 
described above, this action includes final amendments to the NSPS 
subparts VV and VVa (NSPS for VOC from equipment leaks in SOCMI) based 
on its reconsideration of certain aspects of these NSPS subparts that 
were raised in an administrative petition which the Agency granted 
pursuant to section 307(d)(7)(B) of the CAA. In January 2008, the EPA 
received one petition for reconsideration of the NSPS for VOC from 
equipment leaks in SOCMI (40 CFR part 60, subparts VV and VVa) and the 
NSPS for equipment leaks in petroleum refineries (40 CFR part 60, 
subparts GGG and GGGa) pursuant to CAA section 307(d)(7)(B) from the 
following petitioners: American Chemistry Council, American Petroleum 
Institute (API), and National Petrochemical and Refiners Association 
(now the American Fuel and Petrochemical Manufacturers). A copy of the 
petition and subsequent EPA correspondence granting reconsideration is 
provided in the docket for this rulemaking (see Docket No. EPA-HQ-OAR-
2022-0730). The petitioners primarily requested that the EPA reconsider 
four provisions in those rules: (1) The clarification of the definition 
of process unit in subparts VV, VVa, GGG, and GGGa; (2) the assignment 
of shared storage vessels to specific process units in subparts VV, 
VVa, GGG, and GGGa; (3) the monitoring of connectors in subpart VVa; 
and (4) the definition of capital expenditure in subpart VVa.\15\ The 
rationale for this request is provided in the petition. The petitioners 
also requested that the EPA stay the effectiveness of these provisions 
of the rule pending resolution of their petition for reconsideration. 
On March 4, 2008, the EPA sent a letter to the petitioners informing 
them that the EPA was granting their request for reconsideration on 
issues (2) through (4) above. The letter also indicated that the EPA 
was not taking action on the first issue related to the definition of 
process unit. Finally, the letter indicated that the EPA was granting a 
90-day stay of the provisions of the rules under reconsideration (see 
CAA section 307(d)(7)(B)), as well as the clarification of the 
definition of process unit, because of its reliance upon the new 
provision on the allocation of shared storage vessels. On June 2, 2008, 
the EPA published three actions in the Federal Register relative to 
extending the 90-day stay. Specifically, the EPA published a direct 
final rule (73 FR 31372) and a parallel proposal (73 FR 31416) in the 
Federal Register to extend the stay until we took final action on the 
issues of which the EPA granted reconsideration. Under the direct final 
rule, the stay would take effect 30 days after the close of the comment 
period on the proposed stay if no adverse comments were received. The 
third notice published that same day was an interim final rule 
extending the 90-day stay at the time for an additional 60 days so that 
the stay would not expire before the direct final rule could take 
effect (73 FR 31376). The EPA did not receive adverse comments on the 
proposed stay and, as a result, the stay became effective August 1, 
2008.
---------------------------------------------------------------------------

    \15\ Note that this final action does not respond to the 
petition for reconsideration of NSPS subparts GGG and GGGa, as the 
EPA is not reviewing those subparts in this action.
---------------------------------------------------------------------------

    In the three June 2, 2008 actions, the EPA indicated that it would 
be publishing a Federal Register notice in response to the petition; 
this action constitutes such notice and formally responds to the issues 
raised in the petition with respect to NSPS subparts VV and VVa. This 
final action presents the EPA's revisions to the NSPS for VOC from 
equipment leaks in SOCMI based on the EPA's reconsideration of issues 
(2) through (4) in the petition. We are also finalizing amendments that 
address the stay on issue (1) in the petition. See sections III.E and 
IV.E of this preamble for details about these final amendments.

B. What are the source categories and how did the previous standards 
regulate emissions?

    The source categories that are the subject of this final action are 
the SOCMI source category subject to the HON and 11 Polymers and Resins 
Production source categories subject to the P&R I and P&R II NESHAP. 
This final action also addresses equipment leaks in the SOCMI and SOCMI 
air oxidation unit processes, distillation operations, and reactor 
processes. The NESHAP and NSPS included in this action that regulate 
emission sources from the SOCMI and Polymers and Resins Production 
source categories are described below.
1. HON
    The sources affected by the HON include heat exchange systems and 
maintenance wastewater located at SOCMI facilities that are regulated 
under NESHAP subpart F; process vents, storage vessels, transfer racks, 
and wastewater streams located at SOCMI facilities that are regulated 
under NESHAP subpart G; equipment leaks associated with SOCMI processes 
regulated under NESHAP subpart H; and equipment leaks from certain non-
SOCMI processes at chemical plants regulated under NESHAP subpart I. As

[[Page 42943]]

previously mentioned, these four NESHAP are more commonly referred 
together as the HON.
    In general, the HON applies to CMPUs that: (1) Produce one of the 
listed SOCMI chemicals,\16\ and (2) either use as a reactant or produce 
a listed organic HAP in the process. A CMPU means the equipment 
assembled and connected by pipes or ducts to process raw materials and 
to manufacture an intended product. A CMPU consists of more than one 
unit operation. A CMPU includes air oxidation reactors and their 
associated product separators and recovery devices; reactors and their 
associated product separators and recovery devices; distillation units 
and their associated distillate receivers and recovery devices; 
associated unit operations; associated recovery devices; and any feed, 
intermediate and product storage vessels, product transfer racks, and 
connected ducts and piping. A CMPU includes pumps, compressors, 
agitators, PRDs, sampling connection systems, open-ended valves or 
lines (OEL), valves, connectors, instrumentation systems, and control 
devices or systems. A CMPU is identified by its primary product.
---------------------------------------------------------------------------

    \16\ See Table 1 to NESHAP subpart F.
---------------------------------------------------------------------------

a. NESHAP Subpart F
    NESHAP subpart F contains provisions to determine which chemical 
manufacturing processes at a SOCMI facility are subject to the HON. 
Table 1 of NESHAP subpart F contains a list of SOCMI chemicals, and 
Table 2 of NESHAP subpart F contains a list of organic HAP regulated by 
the HON. In general, if a process both: (1) Produces one of the listed 
SOCMI chemicals and (2) either uses as a reactant or produces a listed 
organic HAP in the process, then that SOCMI process is subject to the 
HON. Details on how to determine which emission sources (i.e., heat 
exchange systems, process vents, storage vessels, transfer racks, 
wastewater, and equipment leaks) are part of a chemical manufacturing 
process are also contained in NESHAP subpart F. NESHAP subpart F also 
contains monitoring requirements for HAP (i.e., HAP listed in Table 4 
of NESHAP subpart F) that may leak into cooling water from heat 
exchange systems. Additionally, NESHAP subpart F requires sources to 
prepare a description of procedures for managing maintenance wastewater 
as part of a SSM plan.
b. NESHAP Subpart G
    NESHAP subpart G contains the standards for process vents, transfer 
racks, storage vessels, and wastewater at SOCMI facilities; it also 
includes emissions averaging provisions. NESHAP subpart G provides an 
equation representing a site-specific allowable overall emission limit 
for the combination of all emission sources subject to the HON at a 
SOCMI facility. Existing sources must demonstrate compliance using one 
of two approaches: the point-by-point compliance approach or the 
emissions averaging approach. New sources are not allowed to use 
emissions averaging, but rather must demonstrate compliance using the 
point-by-point approach. Under the point-by-point approach, the owner 
or operator would apply control to each Group 1 emission source. A 
Group 1 emission source is a point which meets the control 
applicability criteria, and the owner or operator must reduce emissions 
to specified levels; whereas a Group 2 emission source is one that does 
not meet the criteria and no additional emission reduction is required. 
Under the emissions averaging approach, an owner or operator may elect 
to control different groups of emission sources to different levels 
than specified by the point-by-point approach, as long as the overall 
emissions do not exceed the overall allowable emission level. For 
example, an owner or operator can choose not to control a Group 1 
emission source (or to control the emission source with a less 
effective control technique) if the owner or operator over-controls 
another emission source. For the point-by-point approach, NESHAP 
subpart G contains the following standards:
     Group 1 process vents must reduce emissions of organic HAP 
using a flare meeting 40 CFR 63.11(b); reduce emissions of total 
organic HAP or TOC by 98 percent by weight or to an exit concentration 
of 20 ppmv; \17\ or achieve and maintain a TRE index value \18\ greater 
than 1.0.\19\
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    \17\ The phrase ``whichever is less stringent'' was originally 
used as part of this NESHAP standard; however, we have determined 
the phrase does not serve any meaningful purpose and are removing it 
in this final action. For specific details about this editorial 
correction, refer to section 4.3 of the document titled Summary of 
Public Comments and Responses for New Source Performance Standards 
for the Synthetic Organic Chemical Manufacturing Industry and 
National Emission Standards for Hazardous Air Pollutants for the 
Synthetic Organic Chemical Manufacturing Industry and Group I & II 
Polymers and Resins Industry, which is available in the docket for 
this rulemaking.
    \18\ See section III.C.3.a of the preamble to the proposed rule 
(88 FR 25080, April 25, 2023) for a description of the TRE index 
value and how the concept is currently used in the HON.
    \19\ Halogenated vent streams (as defined in NESHAP subpart G) 
from Group 1 process vents may not be vented to a flare and must 
reduce the overall emissions of hydrogen halides and halogens by 99 
percent (or 95 percent for control devices installed prior to 
December 31, 1992) or reduce the outlet mass emission rate of total 
hydrogen halides and halogens to less than 0.45 kg/hr.
---------------------------------------------------------------------------

     Group 1 transfer racks must reduce emissions of total 
organic HAP by 98 percent by weight or to an exit concentration of 20 
ppmv; \20\ or reduce emissions of organic HAP using a flare meeting 40 
CFR 63.11(b), using a vapor balancing system, or by routing emissions 
to a fuel gas system or to a process.
---------------------------------------------------------------------------

    \20\ See footnote 17.
---------------------------------------------------------------------------

     Group 1 storage vessels must reduce emissions of organic 
HAP using a fixed roof tank equipped with an IFR; using an external 
floating roof (EFR); using an EFR tank converted to a fixed roof tank 
equipped with an IFR; by routing emissions to a fuel gas system or to a 
process; or reduce emissions of organic HAP by 95 percent by weight 
using a closed vent system (i.e., vapor collection system) and control 
device, or combination of control devices (or reduce emissions of 
organic HAP by 90 percent by weight using a closed vent system and 
control device if the control device was installed before December 31, 
1992).
     Group 1 process wastewater streams and equipment managing 
such streams at both new and existing sources must meet control 
requirements for: (1) Waste management units including wastewater 
tanks, surface impoundments, containers, individual drain systems, and 
oil-water separators; (2) treatment processes including the design 
steam stripper, biological treatment units, or other treatment devices; 
and (3) closed vent systems and control devices such as flares, 
catalytic incinerators, etc. Existing sources are not required to meet 
control requirements if Group 1 process wastewater streams are included 
in a 1 megagram per year source-wide exemption allowed by NESHAP 
subpart G.
     In general, Group 2 emission sources are not required to 
apply any additional emission controls (provided they remain below 
Group 1 thresholds); however, they are subject to certain monitoring, 
reporting, and recordkeeping requirements to ensure that they were 
correctly determined to be Group 2 and that they remain Group 2.
c. NESHAP Subpart H
    NESHAP subpart H contains the standard for equipment leaks at SOCMI 
facilities, including leak detection and repair (LDAR) provisions and 
other control requirements. Equipment regulated includes pumps, 
compressors, agitators, PRDs, sampling connection

[[Page 42944]]

systems, OEL, valves, connectors, surge control vessels, bottoms 
receivers, and instrumentation systems in organic HAP service. A piece 
of equipment is in organic HAP service if it contains or contacts a 
fluid that is at least 5 percent by weight organic HAP. Depending on 
the type of equipment, the standards require either periodic monitoring 
for and repair of leaks, the use of specified equipment to minimize 
leaks, or specified work practices. Monitoring for leaks must be 
conducted using EPA Method 21 in appendix A-7 to 40 CFR part 60 or 
other approved equivalent monitoring techniques.
d. NESHAP Subpart I
    NESHAP subpart I provides the applicability criteria for certain 
non-SOCMI processes subject to the negotiated regulation for equipment 
leaks. Regulated equipment is the same as that for NESHAP subpart H.
2. P&R I NESHAP
    The P&R I NESHAP generally follows and refers to the requirements 
of the HON, with additional requirements for batch process vents. 
Generally, the P&R I NESHAP applies to EPPUs and associated equipment. 
Similar to a CMPU in the HON, an EPPU means a collection of equipment 
assembled and connected by hard-piping or duct work used to process raw 
materials and manufacture elastomer product. The EPPU includes unit 
operations, recovery operations, process vents, storage vessels, and 
equipment that are covered by equipment leak standards and produce one 
of the elastomer types listed as an elastomer product, including: butyl 
rubber, epichlorohydrin elastomer, ethylene propylene rubber, halobutyl 
rubber, HypalonTM, neoprene, nitrile butadiene latex, 
nitrile butadiene rubber, polybutadiene rubber/styrene butadiene rubber 
by solution, polysulfide rubber, styrene butadiene latex, and styrene 
butadiene rubber by emulsion. An EPPU consists of more than one unit 
operation. An EPPU includes, as ``equipment,'' pumps, compressors, 
agitators, PRDs, sampling connection systems, OEL, valves, connectors, 
surge control vessels, bottoms receivers, instrumentation systems, and 
control devices or systems.
    The emissions sources affected by the P&R I NESHAP include heat 
exchange systems and maintenance wastewater at P&R I facilities 
regulated under NESHAP subpart F; storage vessels, transfer racks, and 
wastewater streams at P&R I facilities regulated under NESHAP subpart 
G; and equipment leaks at P&R I facilities regulated under NESHAP 
subpart H. Process vents are also regulated emission sources but, 
unlike the HON, these emissions sources are subdivided into front and 
back-end process vents in the P&R I NESHAP. The front-end are unit 
operations prior to and including the stripping operations. These are 
further subdivided into continuous front-end process vents regulated 
under NESHAP subpart G and batch front-end process vents that are 
regulated according to the requirements within the P&R I NESHAP. Back-
end unit operations include filtering, coagulation, blending, 
concentration, drying, separating, and other finishing operations, as 
well as latex and crumb storage. The requirements for back-end process 
vents are not subcategorized into batch or continuous and are also 
found within the P&R I NESHAP.
3. P&R II NESHAP
    The P&R II NESHAP regulates HAP emissions from two source 
categories, Epoxy Resins Production (also referred to as BLR) and Non-
Nylon Polyamides Production (also referred to as WSR). The P&R II 
NESHAP takes a different regulatory and format approach from the P&R I 
NESHAP but still refers to HON provisions for a portion of the 
standards. BLR are resins made by reacting epichlorohydrin and 
bisphenol A to form diglycidyl ether of bisphenol-A. WSR are polyamide/
epichlorohydrin condensates which are used to increase the tensile 
strength of paper products.
    The emission sources affected by the P&R II NESHAP are all HAP 
emission points within a facility related to the production of BLR or 
WSR. These emission points include process vents, storage tanks, 
wastewater systems, and equipment leaks. Equipment includes connectors, 
pumps, compressors, agitators, PRDs, sampling connection systems, OEL, 
and instrumentation system in organic HAP service. Equipment leaks are 
regulated under the HON (i.e., NESHAP subpart H).
    Process vents, storage tanks, and wastewater systems combined are 
regulated according to a production-based emission rate (e.g., pounds 
HAP per million pounds BLR or WSR produced). For existing sources, the 
rate shall not exceed 130 pounds per 1 million pounds of BLR produced 
and 10 pounds per 1 million pounds of WSR produced. For new sources, 
BLR requires all uncontrolled emissions to achieve 98 percent reduction 
or limits the total emissions to 5,000 pounds of HAP per year. New WSR 
sources are limited to 7 pounds of HAP per 1 million pounds of WSR 
produced.
4. NSPS Subpart VVa
    NSPS subpart VVa contains VOC standards for leaks from equipment 
within a process unit for which construction, reconstruction, or 
modification commenced after November 7, 2006. Under NSPS subpart VVa, 
equipment means each pump, compressor, PRD, sampling connection system, 
OEL, valve, and flange or other connector in VOC service and any 
devices or systems required by the NSPS. Process units consist of 
components assembled to produce, as intermediate or final products, one 
or more of the chemicals listed in 40 CFR 60.489. A process unit can 
operate independently if supplied with sufficient feed or raw materials 
and sufficient storage facilities for the product. The standards in 
NSPS subpart VVa include LDAR provisions and other control 
requirements. A piece of equipment is in VOC service if it contains or 
contacts a fluid that is at least 10 percent by weight VOC. Depending 
on the type of equipment, the standards require either periodic 
monitoring for and repair of leaks, the use of specified equipment to 
minimize leaks, or specified work practices. Monitoring for leaks must 
be conducted using EPA Method 21 in appendix A-7 to 40 CFR part 60 or 
other approved equivalent monitoring techniques.
5. NSPS Subpart III
    NSPS subpart III regulates VOC emissions from SOCMI air oxidation 
reactors for which construction, reconstruction, or modification 
commenced after October 21, 1983. For the purpose of NSPS subpart III, 
air oxidation reactors are devices or process vessels in which one or 
more organic reactants are combined with air, or a combination of air 
and oxygen, to produce one or more organic compounds. The affected 
facility is designated as a single air oxidation reactor with its own 
individual recovery system (if any) or the combination of two or more 
air oxidation reactors and the common recovery system they share that 
produces one or more of the chemicals listed in 40 CFR 60.617 as a 
product, co-product, by-product, or intermediate. The BSER for reducing 
VOC emissions from SOCMI air oxidation units was identified as 
combustion (e.g., incineration, flares) and the standard of performance 
requires owners and operators of an affected facility to reduce 
emissions of TOC (minus methane and ethane) by 98 percent by weight or 
to a concentration of 20 ppmv on a dry basis corrected to

[[Page 42945]]

3 percent oxygen; \21\ combust the emissions in a flare meeting 40 CFR 
60.18(b); or maintain a TRE index value \22\ greater than 1.0 without 
use of VOC emission control devices.
---------------------------------------------------------------------------

    \21\ The phrase ``whichever is less stringent'' was originally 
used as part of this NSPS standard; however, we have determined the 
phrase does not serve any meaningful purpose and are removing it in 
this final action. For specific details about this editorial 
correction, refer to section 5.1 of the document titled Summary of 
Public Comments and Responses for New Source Performance Standards 
for the Synthetic Organic Chemical Manufacturing Industry and 
National Emission Standards for Hazardous Air Pollutants for the 
Synthetic Organic Chemical Manufacturing Industry and Group I & II 
Polymers and Resins Industry, which is available in the docket for 
this rulemaking.
    \22\ See section III.C.3.b of the preamble to the proposed rule 
(88 FR 25080, April 25, 2023) for a description of the TRE index 
value and how the concept is used in NSPS subpart III.
---------------------------------------------------------------------------

6. NSPS Subpart NNN
    NSPS subpart NNN regulates VOC emissions from SOCMI distillation 
operations for which construction, reconstruction, or modification 
commenced after December 30, 1983. For the purpose of NSPS subpart NNN, 
distillation operations are operations separating one or more feed 
stream(s) into two or more exit stream(s), each exit stream having 
component concentrations different from those in the feed stream(s); 
and the separation is achieved by the redistribution of the components 
between the liquid and vapor-phase as they approach equilibrium within 
a distillation unit. The affected facility is designated as a single 
distillation column with its own individual recovery system (if any) or 
the combination of two or more distillation columns and the common 
recovery system they share that is part of a process unit that produces 
any of the chemicals listed in 40 CFR 60.667 as a product, co-product, 
by-product, or intermediate. The BSER for reducing VOC emissions from 
SOCMI distillation operations was identified as combustion (e.g., 
incineration, flares) and the standard of performance requires owners 
and operators of an affected facility to reduce emissions of TOC (minus 
methane and ethane) by 98 percent by weight or to a concentration of 20 
ppmv on a dry basis corrected to 3 percent oxygen; \23\ combust the 
emissions in a flare meeting 40 CFR 60.18(b); or maintain a TRE index 
value \24\ greater than 1.0 without use of VOC emission control 
devices.
---------------------------------------------------------------------------

    \23\ See footnote 21.
    \24\ See section III.C.3.b of the preamble to the proposed rule 
(88 FR 25080, April 25, 2023) for a description of the TRE index 
value and how the concept is used in NSPS subpart NNN.
---------------------------------------------------------------------------

7. NSPS Subpart RRR
    NSPS subpart RRR regulates VOC emissions from SOCMI reactor 
processes for which construction, reconstruction, or modification 
commenced after June 29, 1990. For the purpose of NSPS subpart RRR, 
reactor processes are unit operations in which one or more chemicals, 
or reactants other than air, are combined or decomposed in such a way 
that their molecular structures are altered and one or more new organic 
compounds are formed. The affected facility is designated as a single 
reactor process with its own individual recovery system (if any) or the 
combination of two or more reactor processes and the common recovery 
system they share that is part of a process unit that produces any of 
the chemicals listed in 40 CFR 60.707 as a product, co-product, by-
product, or intermediate. The BSER for reducing VOC emissions from 
SOCMI reactor processes was identified as combustion (e.g., 
incineration, flares) and the standard of performance requires owners 
and operators of an affected facility to reduce emissions of TOC (minus 
methane and ethane) by 98 percent by weight or to a concentration of 20 
ppmv on a dry basis corrected to 3 percent oxygen; \25\ combust the 
emissions in a flare meeting 40 CFR 60.18(b); or maintain a TRE index 
value \26\ greater than 1.0 without use of VOC emission control 
devices.
---------------------------------------------------------------------------

    \25\ See footnote 21.
    \26\ See section III.C.3.b of the preamble to the proposed rule 
(88 FR 25080, April 25, 2023) for a description of the TRE index 
value and how the concept is used in NSPS subpart RRR.
---------------------------------------------------------------------------

C. What changes did we propose in our April 25, 2023, proposal?

1. NESHAP
a. Proposed Actions Related to CAA Section 112(f) Risk Assessment
    To reduce risk from the SOCMI source category to an acceptable 
level, we proposed under CAA section 112(f) to require (in the HON) 
control of EtO emissions from: (1) Process vents, (2) storage vessels, 
(3) equipment leaks, (4) heat exchange systems, and (5) wastewater ``in 
ethylene oxide service'' (see 88 FR 25080, April 25, 2023, for our 
proposed definition of ``in ethylene oxide service''). We also proposed 
requirements to reduce EtO emissions from maintenance vents, flares, 
and PRDs.
     For process vents and storage vessels in EtO service, we 
proposed owners and operators reduce emissions of EtO by either: (1) 
Venting emissions through a closed-vent system to a control device that 
reduces EtO by greater than or equal to 99.9 percent by weight, to a 
concentration less than 1 ppmv for each process vent and storage 
vessel, or to less than 5 lb/yr for all combined process vents; or (2) 
venting emissions through a closed-vent system to a flare meeting the 
proposed operating and monitoring requirements for flares in NESHAP 
subpart F.
     For equipment leaks in EtO service, we proposed the 
following combined requirements: monitoring of connectors in gas/vapor 
and light liquid service at a leak definition of 100 ppm on a monthly 
basis with no reduction in monitoring frequency and no delay of repair; 
light liquid pump monitoring at a leak definition of 500 ppm monthly; 
and gas/vapor and light liquid valve monitoring at a leak definition of 
100 ppm monthly with no reduction in monitoring frequency and no delay 
of repair.
     For heat exchange systems in EtO service, we proposed to 
require owners or operators to conduct more frequent leak monitoring 
(weekly instead of quarterly) and repair leaks within 15 days from the 
sampling date (in lieu of the current 45-day repair requirement after 
receiving results of monitoring indicating a leak), and delay of repair 
would not be allowed.
     For wastewater in EtO service, we proposed to revise the 
Group 1 wastewater stream threshold for sources to include wastewater 
streams in EtO service.
     For maintenance vents, we proposed a requirement that 
owners and operators cannot release more than 1.0 ton of EtO from all 
maintenance vents combined in any consecutive 12-month period.
     For flares, we proposed a requirement that owners and 
operators can send no more than 20 tons of EtO to all of their flares 
combined from all HON emission sources at a facility in any consecutive 
12-month period.
     For PRDs in EtO service, we proposed that any atmospheric 
PRD release is a violation of the standard.
    To reduce risk from the Neoprene Production source category to an 
acceptable level, we proposed under CAA section 112(f) to require (in 
the P&R I NESHAP) control of chloroprene for: (1) Process vents, (2) 
storage vessels, and (3) wastewater ``in chloroprene service'' (see 88 
FR 25080, April 25, 2023, for our proposed definition of ``in 
chloroprene service''). We also proposed requirements to reduce 
chloroprene emissions from maintenance vents and PRDs.
     For process vents and storage vessels in chloroprene 
service, we

[[Page 42946]]

proposed owners and operators reduce emissions of chloroprene by 
venting emissions through a closed-vent system to a control device that 
reduces chloroprene by greater than or equal to 99.9 percent by weight, 
to a concentration less than 1 ppmv for each process vent and storage 
vessel, or to less than 5 lb/yr for all combined process vents.
     For wastewater in chloroprene service, we proposed to 
revise the Group 1 wastewater stream threshold for sources to include 
wastewater streams in chloroprene service.
     For maintenance vents, we proposed a requirement that 
owners and operators cannot release more than 1.0 ton of chloroprene 
from all maintenance vents combined in any consecutive 12-month period.
     For PRDs in chloroprene service, we proposed that any 
atmospheric PRD release is a violation of the standard.
     We also proposed a facility-wide chloroprene emissions cap 
for all neoprene production emission sources as a backstop.
    Based on our ample margin of safety analysis, we proposed that the 
controls to reduce EtO emissions at HON processes and chloroprene 
emissions at neoprene production processes to get risks to an 
acceptable level (described in this section of the preamble) would also 
provide an ample margin of safety to protect public health. We also 
proposed that HAP emissions from the source categories do not result in 
an adverse environmental effect, and that it is not necessary to set a 
more stringent standard to prevent, taking into consideration costs, 
energy, safety, and other relevant factors, an adverse environmental 
effect.
b. Proposed Actions Related to CAA Section 112(d)(6) Technology Review
    Pursuant to the CAA section 112(d)(6) technology review for the HON 
and the P&R I, and P&R II NESHAP, we proposed that no revisions to the 
current standards beyond the fenceline monitoring work practice 
standard discussed below and those proposed under CAA section 112(f) 
are necessary for transfer racks, wastewater streams, and equipment 
leaks; however, we did propose additional changes under CAA section 
112(d)(6) for heat exchange systems, storage vessels and process vents.
     For HON and P&R I heat exchange systems, we proposed 
requirements that owners or operators must use the Modified El Paso 
Method and repair leaks of total strippable hydrocarbon concentration 
(as methane) in the stripping gas of 6.2 ppmv or greater. The P&R II 
NESHAP currently does not regulate HAP emissions from heat exchange 
systems.
     For HON and P&R I storage vessels, we proposed to revise 
applicability thresholds to require existing storage vessels between 38 
m\3\ (10,000 gal) and 151 m\3\ (40,000 gal) with a vapor pressure >=6.9 
kilopascals to add control, and also require upgraded deck fittings and 
controls for guidepoles for all IFR storage vessels. For P&R II storage 
vessels, we proposed that no revisions to the current standards are 
necessary.
     For HON and P&R I process vents, we proposed to: (1) 
Remove the TRE concept in its entirety; (2) remove 50 ppmv and 0.005 
scmm Group 1 process vent thresholds; and (3) redefine a Group 1 
process vent (require control) as any process vent that emits >=1.0 lb/
hr of total organic HAP. For P&R II process vents, we proposed that no 
revisions to the current standards are necessary.
    Under CAA section 112(d)(6), we also proposed a fenceline 
monitoring work practice standard requiring owners and operators to 
monitor for any of six specific HAP (i.e., benzene, 1,3-butadiene, 
ethylene dichloride, vinyl chloride, EtO, and chloroprene) if their 
site uses, produces, stores, or emits any of them, and conduct root 
cause analysis and corrective action upon exceeding the annual average 
concentration action level set forth for each HAP. We also requested 
public comments on whether to promulgate the fenceline monitoring work 
practice standards, including the proposed action levels for EtO and 
chloroprene, under the second step of the CAA section 112(f)(2) 
residual risk decision framework to provide an ample margin of safety 
to protect public health in light of facility-wide risks.
c. Proposed Actions Related to CAA Section 112(d)(2) and (3), and 
112(h)
    We proposed other requirements for the HON and P&R I and P&R II 
NESHAP based on analyses performed pursuant to CAA sections 112(d)(2) 
and (3), and 112(h), and that are consistent with Sierra Club v. EPA, 
551 F.3d 1019 (D.C. Cir. 2008), ensuring that CAA section 112 standards 
apply continuously, including:
     new monitoring and operational requirements for flares in 
the HON and P&R I NESHAP;
     work practice standards for periods of SSM for certain HON 
and P&R I vent streams (i.e., PRD releases, maintenance vents, and 
planned routine maintenance of storage vessels);
     regulatory provisions for vent control bypasses for 
certain HON and P&R I vent streams (i.e., closed vent systems 
containing bypass lines);
     dioxins and furans emission limits in the HON and the P&R 
I and P&R II NESHAP;
     new monitoring requirements for HON and P&R I pressure 
vessels;
     new emission standards for HON & P&R I surge control 
vessels and bottoms receivers;
     a revised applicability threshold for HON transfer racks;
     requirements in the P&R II NESHAP for heat exchange 
systems;
     requirements in the P&R II NESHAP for WSR sources and 
equipment leaks;
     to require owners and operators that use a sweep, purge, 
or inert blanket between the IFR and fixed roof of a storage vessel to 
route emissions through a closed vent system and control device;
     to remove exemptions in the HON and the P&R I and P&R II 
NESHAP from the requirement to comply during periods of SSM; and
     to remove affirmative defense provisions from the P&R I 
NESHAP that were adopted in 2011.
d. Other Proposed Actions
    In addition to the actions described in the sections above related 
to NESHAP, we also proposed:
     changes to the HON and the P&R I and P&R II NESHAP 
recordkeeping and reporting requirements to require the use of 
electronic reporting of performance test reports and periodic reports;
     restructuring of all HON definitions;
     monitoring requirements for adsorbers that cannot be 
regenerated and regenerative adsorbers that are regenerated offsite;
     to require subsequent performance testing on non-flare 
control devices no later than 60 calendar months after the previous 
performance test; and
     to correct section reference errors and make other minor 
editorial revisions.
2. NSPS
a. Proposed Actions Related to CAA Section 111(b)(1)(B) Review
    Pursuant to the CAA section 111(b)(1)(B) reviews for the SOCMI NSPS 
rules, we proposed new NSPS for equipment leaks (NSPS subpart VVb) and 
process vents associated with air oxidation units (NSPS subpart IIIa), 
distillation operations (NSPS subpart NNNa), and reactor processes 
(NSPS subpart RRRa).
     For NSPS subpart VVb, we proposed the same requirements in

[[Page 42947]]

NSPS subpart VVa plus a requirement that all gas/vapor and light liquid 
valves be monitored monthly at a leak definition of 100 ppm and all 
connectors be monitored once every 12 months at a leak definition of 
500 ppm.
     For NSPS subparts IIIa, NNNa, and RRRa, we proposed the 
same requirements in NSPS subparts III, NNN, and RRR, except we 
proposed to: (1) Eliminate the TRE concept in its entirety (including 
the removal of the alternative of maintaining a TRE index value greater 
than 1 without the use of control device and the limited applicability 
exemptions) and instead require owners and operators to reduce 
emissions of TOC (minus methane and ethane) from all vent streams of an 
affected facility (i.e., SOCMI air oxidation unit processes, 
distillation operations, and reactor processes for which construction, 
reconstruction, or modification commences after April 25, 2023) by 98 
percent by weight or to a concentration of 20 ppmv on a dry basis 
corrected to 3 percent oxygen, or combust the emissions in a flare 
meeting the same operating and monitoring requirements for flares that 
we proposed for flares subject to the HON; (2) eliminate the relief 
valve discharge exemption from the definition of ``vent stream'' such 
that any relief valve discharge to the atmosphere of a vent stream is a 
violation of the emissions standard; (3) require the same work practice 
standards for maintenance vents that we proposed for HON process vents; 
and (4) require the same monitoring requirements that we proposed for 
HON process vents for adsorbers that cannot be regenerated and 
regenerative adsorbers that are regenerated offsite.
b. Proposed Actions Related to NSPS Subparts VV and VVa Reconsideration
    In response to the January 2008 petition for reconsideration we 
proposed: (1) Definitions for ``process unit'' for NSPS subparts VV and 
VVa; (2) to remove the requirements in 40 CFR 60.482-1(g) (for NSPS 
subpart VV) and 40 CFR 60.482-1a(g) (for NSPS subpart VVa) that are 
related to a method for assigning shared storage vessels to specific 
process units; (3) to remove the connector monitoring provisions from 
NSPS subpart VVa at 40 CFR 60.482-11a in their entirety and instead, 
include connector monitoring provisions in NSPS subpart VVb; and (4) to 
revise the ``capital expenditure'' definition in NSPS subpart VVa at 40 
CFR 60.481a to reflect the definition used in NSPS subpart VV at 40 CFR 
60.481 for owners or operators that start a new, reconstructed, or 
modified affected source prior to November 16, 2007.
c. Other Proposed Actions
    In addition to the actions described in the sections above related 
to the CAA section 111(b)(1)(B) reviews for the SOCMI NSPS rules and 
the NSPS subparts VV and VVa reconsideration, we also proposed:
     standards in NSPS subparts VVb, IIIa, NNNa, and RRRa that 
apply at all times;
     the use of electronic reporting of performance test 
reports and periodic reports;
     several corrections to the calibration drift assessment 
requirements in NSPS subpart VVa; and
     to require subsequent performance testing on non-flare 
control devices no later than 60 calendar months after the previous 
performance test.

III. What is included in this final rule?

    This action finalizes the EPA's determinations pursuant to the 
applicable provisions of CAA section 112 for the SOCMI source category 
and various polymers and resins source categories and amends the HON 
and P&R I and P&R II NESHAP based on those determinations. In addition, 
this action finalizes determinations of our review of the SOCMI NSPS 
rules pursuant to CAA section 111(b)(1)(B). This actions also finalizes 
other changes to the NESHAP, including adding requirements and 
clarifications for periods of SSM and bypasses; revising the operating 
and monitoring requirements for flares; adding provisions for 
electronic reporting; and other editorial and technical changes. 
Additionally, this action finalizes amendments to NSPS subparts VV and 
VVa in response to the January 2008 petition for reconsideration. This 
action also reflects several changes to the April 25, 2023 proposal (88 
FR 25080), in consideration of comments received during the public 
comment period as described in section IV of this preamble.

A. What are the final rule amendments based on the risk review for the 
SOCMI and Neoprene Production source categories NESHAP?

    Consistent with the proposal, the EPA determined that the risks for 
the SOCMI and Neoprene Production source categories under the previous 
MACT standards are unacceptable. When risks are unacceptable, the EPA 
must determine the emissions standards necessary to reduce risk to an 
acceptable level. As such, the EPA is promulgating final amendments to 
the HON pursuant to CAA section 112(f)(2) that require control of EtO 
for: (1) Process vents, (2) storage vessels, (3) equipment leaks, (4) 
heat exchange systems, and (5) wastewater ``in ethylene oxide 
service.'' We are also finalizing requirements to reduce EtO emissions 
from maintenance vents and PRDs. As discussed in section IV.A of this 
preamble, implementation of these controls will reduce risk to an 
acceptable level and provide an ample margin of safety to protect 
public health from source category emissions points. In addition, the 
fenceline monitoring requirements being finalized in this action will 
further reduce whole-facility EtO and chloroprene emissions at 
facilities with HON and Neoprene Production processes, with 
consequential reductions in risks from these pollutants. In general, we 
are finalizing all of the EtO related requirements as proposed (for 
HON), except: we are not finalizing (in response to persuasive comments 
received during the public comment period) the proposed requirement at 
40 CFR 63.108(p) that would prohibit owners and operators from sending 
more than 20 tons of EtO to all of their flares combined in any 
consecutive 12-month period. In addition to the primary CAA section 
112(d)(6)-based fenceline monitoring program action levels that we are 
finalizing for all six HAP that reflect compliance with the source 
category-specific emissions limits for SOCMI and P&R I source category 
processes (see section III.B.1 of this preamble), we are also 
finalizing separately, in the P&R I NESHAP for Neoprene Production 
sources, an additional secondary action level under CAA section 
112(f)(2) for fenceline monitoring of chloroprene emissions. This 
secondary action level for chloroprene for facilities with Neoprene 
Production sources is the same action level that was proposed. The 
primary chloroprene action level, which applies to sources subject to 
40 CFR subpart H in the HON, is higher than what was proposed, but 
reflects the modeled emissions concentrations expected to result from 
compliance with the other emission standards adopted in the final rule, 
as we discussed in the proposed rule. See 88 FR at 25145/col. 2. The 
secondary chloroprene action level will further reduce whole-facility 
risks caused by such emissions from facilities with Neoprene Production 
sources, consistent with the goal to provide an ample margin of safety 
to protect public health. For this reason, for facilities with Neoprene 
Production sources we are promulgating the secondary chloroprene action 
level we had proposed under CAA section 112(d)(6)

[[Page 42948]]

under our CAA section 112(f)(2) authority, as we requested comment on 
in the proposed rule. See id., at 25145/col. 3.
    Also, based on comments received on the proposed rulemaking, we are 
clarifying in this final action that:
     we mean ``the procedures specified in Sec.  63.109'' 
instead of ``sampling and analysis'' within the definitions of ``in 
ethylene oxide service'' for storage vessels, equipment leaks, and heat 
exchange systems (see 40 CFR 63.101);
     the sampling site for determining whether an emissions 
source is in EtO service is after the last recovery device (if any 
recovery devices are present) but prior to the inlet of any control 
device that is present and prior to release to the atmosphere (see 40 
CFR 63.109(a));
     owners and operators can use good engineering judgment to 
determine the percent of EtO of the process fluid cooled by the heat 
exchange system similar to what we are allowing for equipment leaks in 
40 CFR 63.109(c)(2) (see 40 CFR 63.109(e));
     the 5 lb/yr EtO mass threshold for combined process vents 
in EtO service is on a CMPU-by-CMPU basis (see 40 CFR 63.113(j)(2), 40 
CFR 63.124(a)(4) and (a)(4)(iii), and within the definition of ``in 
ethylene oxide service'' for process vents);
     owners and operators may delay repair of equipment leaks 
in EtO service, and heat exchange systems in EtO service, indefinitely 
as long as there is no longer an active EtO leak once the equipment is 
isolated and not in EtO service (see 40 CFR 63.104(h)(6) and 40 CFR 
63.171(b));
     we mean ``process wastewater'' instead of ``wastewater'' 
in 40 CFR 63.132(c)(1)(iii) and (d)(1)(ii);
     owners and operators can demonstrate compliance with the 
standards for wastewater in EtO service if the concentration of EtO is 
reduced, by removal or destruction, to a level less than 1 ppmw as 
determined in the procedures specified in 40 CFR 63.145(b) (see 40 CFR 
63.138(b)(3) and (c)(3)); and
     owners and operators can use test methods specified in 40 
CFR 63.109(d) for analysis of EtO in wastewater (see 40 CFR 
63.144(b)(5)(i)).
    Additionally, the EPA is promulgating final amendments to the P&R I 
NESHAP for Neoprene Production sources pursuant to CAA section 
112(f)(2) that require control of chloroprene for: (1) Process vents, 
(2) storage vessels, (3) wastewater ``in chloroprene service.'' We are 
also finalizing requirements to reduce chloroprene emissions from 
maintenance vents and PRDs. As discussed in section IV.A of this 
preamble, implementation of these controls will reduce risk to an 
acceptable level and provide an ample margin of safety to protect 
public health from the Neoprene Production source category. In general, 
we are finalizing all of the chloroprene related requirements as 
proposed (for Neoprene Production sources in the P&R I NESHAP), except 
in response to persuasive comments received during the public comment 
period: (1) We are not finalizing the facility-wide chloroprene 
emissions cap at 40 CFR 63.483(a)(10) that would prohibit owners and 
operators from emitting 3.8 tpy of chloroprene in any consecutive 12-
month period from all neoprene production emission sources; (2) we are 
revising the performance standard from a 99.9 percent by weight 
reduction requirement to a 98 percent by weight reduction requirement 
for storage vessels in chloroprene service (see 40 CFR 63.484(u) and 40 
CFR 53.510), continuous front-end process vents in chloroprene service 
(see 40 CFR 63.485(y) and 40 CFR 53.510), and batch front-end process 
vents in chloroprene service (see 40 CFR 63.487(j)); (3) we are 
finalizing a requirement that owners and operators reduce emissions of 
chloroprene from back-end process vents in chloroprene service at 
affected sources producing neoprene by venting emissions through a 
closed-vent system to a non-flare control device that reduces 
chloroprene by greater than or equal to 98 percent by weight, to a 
concentration less than 1 ppmv for each process vent, or to less than 5 
lb/yr for all combined process vents (see 40 CFR 63.494(a)(7)); and (4) 
we are finalizing in the primary CAA section 112(d)(6)-based fenceline 
monitoring program action levels for all six HAP addressed in the 
proposal that reflect compliance with the source category-specific 
emissions limits for SOCMI and P&R I source category processes, and 
which subject sources are largely already meeting (see section III.B.1 
of this preamble). Separately, we are also setting an additional 
secondary action level under CAA section 112(f)(2) for fenceline 
monitoring of chloroprene emissions. This standard will further reduce 
whole-facility risks caused by such emissions, consistent with the goal 
to provide an ample margin of safety to protect public health. Also, 
based on comments received on the proposed rulemaking, we are 
clarifying in this final action that:
     we mean ``the procedures specified in Sec.  63.509'' 
instead of ``sampling and analysis'' within the definitions of ``in 
chloroprene service'' for storage vessels (see 40 CFR 63.482);
     the sampling site for determining whether an emissions 
source is in chloroprene service is after the last recovery device (if 
any recovery devices are present) but prior to the inlet of any control 
device that is present and prior to release to the atmosphere (see 40 
CFR 63.509(a)); and
     the 5 lb/yr chloroprene mass threshold for combined 
process vents in chloroprene service is on a EPPU-by-EPPU basis (see 
the definition of ``in chloroprene service'' for process vents).
    Section IV.A.3 of this preamble provides a summary of key comments 
we received on the CAA section 112(f) provisions and our responses.

B. What are the final rule amendments based on the technology review 
for the SOCMI, P&R I, and P&R II source categories NESHAP pursuant to 
CAA section 112(d)(6) and NSPS reviews for the SOCMI source category 
pursuant to CAA section 111(b)(1)(B)?

1. NESHAP
    For transfer racks, wastewater streams, and equipment leaks in the 
SOCMI, P&R I, and P&R II source categories, the EPA is finalizing its 
proposed determination in the technology review that there are no 
developments in practices, processes, and control technologies that 
warrant revisions to the MACT standards beyond those needed under CAA 
section 112(f) or for other purposes besides section 112(d)(6). 
Therefore, with the exception of the fenceline monitoring standards 
that are discussed further below, we are not finalizing revisions to 
the MACT standards for these emission sources under CAA section 
112(d)(6).
    For heat exchange systems, we determined that there are 
developments in practices, processes, and control technologies that 
warrant revisions to the MACT standards for heat exchange systems in 
the SOCMI, P&R I, and P&R II source categories. Therefore, to satisfy 
the requirements of CAA section 112(d)(6), we are revising the MACT 
standards, consistent with the proposed rule (88 FR 25080, April 25, 
2023), to include revisions to the heat exchange system requirements to 
require owners or operators to use the Modified El Paso Method and 
repair leaks of total strippable hydrocarbon concentration (as methane) 
in the stripping gas of 6.2 ppmv or greater. We are also finalizing, as 
proposed, that owners and operators may use the current leak monitoring 
requirements for heat exchange systems at 40 CFR 63.104(b) in lieu of 
using the Modified El Paso Method provided that 99 percent by weight or 
more of the

[[Page 42949]]

organic compounds that could leak into the heat exchange system are 
water soluble and have a Henry's Law Constant less than 5.0E-6 
atmospheres-cubic meters/mol at 25 degrees Celsius. See 40 CFR 
63.104(g) through (j) and (l) (for HON), 40 CFR 63.502(n)(7) (for the 
P&R I NESHAP), and 40 CFR 63.523(d) and 40 CFR 63.524(c) (for the P&R 
II NESHAP).
    For storage vessels, we did not identify any control options for 
storage tanks subject to the P&R II NESHAP. However, we determined that 
there are developments in practices, processes, and control 
technologies that warrant revisions to the MACT standards for storage 
vessels in the SOCMI and P&R I source categories. Therefore, to satisfy 
the requirements of CAA section 112(d)(6), we are revising the MACT 
standards, consistent with the proposed rule (88 FR 25080, April 25, 
2023), to include revisions to the storage vessel applicability 
threshold to require both existing and new storage vessels between 38 
m\3\ and 151 m\3\ with a vapor pressure greater than or equal to 6.9 
kilopascals to reduce emissions of organic HAP by 95 percent utilizing 
a closed vent system and control device, or reduce organic HAP 
emissions either by utilizing an IFR, an EFR, or by routing the 
emissions to a process or a fuel gas system, or vapor balancing. We are 
also finalizing, as proposed, requirements that all openings in an IFR 
(except those for automatic bleeder vents (vacuum breaker vents), rim 
space vents, leg sleeves, and deck drains) be equipped with a deck 
cover; and that the deck cover be equipped with a gasket between the 
cover and the deck; and control requirements for guidepoles for all 
storage vessels equipped with an IFR. See Tables 5 and 6 to subpart G, 
and 40 CFR 63.119(b)(5)(ix), (x), (xi), and (xii) (for HON) and 40 CFR 
63.484(t) (for the P&R I NESHAP).
    For process vents, we did not identify any control options for 
process vents subject to the P&R II NESHAP. However, we determined that 
there are developments in practices, processes, and control 
technologies that warrant revisions to the MACT standards for process 
vents in the SOCMI and P&R I source categories. Therefore, to satisfy 
the requirements of CAA section 112(d)(6), we are revising the MACT 
standards, consistent with the proposed rule (88 FR 25080, April 25, 
2023), to include revisions to the process vent applicability threshold 
to redefine a HON Group 1 process vent and P&R I Group 1 continuous 
front-end process vent (i.e., to require control) as any process vent 
that emits greater than or equal to 1.0 lb/hr of total organic HAP. We 
are also removing, as proposed, the TRE concept in its entirety, and 
removing, as proposed, the 50 ppmv and 0.005 scmm Group 1 process vent 
thresholds. See 40 CFR 63.101 and 40 CFR 63.113(a)(1), (2), and (4) 
(for HON) and 40 CFR 63.482 and 40 CFR 63.485(l)(6), (o)(6), (p)(5), 
and (x) (for the P&R I NESHAP). To satisfy the requirements of CAA 
section 112(d)(6), we are also revising the MACT standards, consistent 
with the proposed rule (88 FR 25080, April 25, 2023), to include 
revisions to the process vent applicability threshold to redefine a P&R 
I Group 1 batch front-end process vent as process vents that release 
total annual organic HAP emissions greater than or equal to 4,536 kg/yr 
(10,000 lb/yr) from all batch front-end process vents combined. See 40 
CFR 63.482, 40 CFR 63.487(e)(1)(iv), 40 CFR 63.488(d)(2), (e)(4), 
(f)(2), and (g)(3) (for the P&R I NESHAP).
    Also, to satisfy the requirements of CAA section 112(d)(6), we are 
revising the MACT standards, consistent with the proposed rule (88 FR 
25080, April 25, 2023), to include a fenceline monitoring work practice 
standard for the SOCMI and P&R I source categories, requiring owners 
and operators to monitor for any of six specific HAP (i.e., benzene, 
1,3-butadiene, ethylene dichloride, vinyl chloride, EtO, and 
chloroprene) if their affected source uses, produces, stores, or emits 
any of them, and to conduct root cause analysis and corrective action 
upon exceeding the annual average concentration action level set forth 
for each HAP. However, based on comments received on the proposed 
rulemaking, we are amending the fenceline monitoring work practice 
standards in the final rule adopted under CAA section 112(d)(6) to 
include the action level of 0.8 ug/m\3\ for chloroprene, which reflects 
compliance with the source category-specific emissions limits for P&R I 
source category processes. The action levels for benzene, 1,3-
butadiene, ethylene dichloride, EtO, and vinyl chloride will also 
correspond to the modeled concentrations resulting from compliance with 
the process emission standards promulgated in the final rule and/or 
levels that HON-subject sources are largely already meeting. 
Separately, we are also setting an additional secondary action level of 
0.3 ug/m\3\ for chloroprene under CAA section 112(f)(2), because this 
standard will further reduce elevated risks from facility-wide 
emissions of this pollutant consistent with the goal to provide an 
ample margin of safety to protect public health. See 40 CFR 63.184 (for 
HON) and 40 CFR 63.502 (for the P&R I NESHAP). In addition, the final 
rule includes burden reduction measures to allow owners and operators 
to skip fenceline measurement periods for specific monitors with a 
history of measurements that are at or below certain specified action 
levels. We have also made a clarification that fenceline monitoring is 
required for owners and operators with affected sources that produce, 
store, or emit one or more of the target analytes; and we have reduced 
the requirements in the final rule for the minimum detection limit of 
alternative measurement approaches (for fenceline monitoring). In 
addition, we have made clarifications on the calculation of delta c 
([Delta]c) \27\ when a site-specific monitoring plan is used to correct 
monitoring location concentrations due to offsite impacts, and we have 
made a change in the required method detection limit for alternative 
test methods from an order of magnitude below the action level to one-
third of the action level. Finally, with the exception of fenceline 
monitoring of chloroprene at P&R I affected sources producing neoprene, 
discussed below, we have changed the compliance date to begin fenceline 
monitoring from 1 to 2 years after the effective date of the final 
rule. For P&R I affected sources producing neoprene, we have changed 
the compliance date for fenceline monitoring of chloroprene to begin no 
later than October 15, 2024, or upon startup, whichever is later, 
subject to the owner or operator seeking the EPA's authorization of an 
extension of up to 2 years from July 15, 2024.
---------------------------------------------------------------------------

    \27\ Delta c, notated as [Delta]c, represents the concentration 
difference between the highest measured concentration and lowest 
measured concentration for a set of samples in one sampling period. 
The sampling period [Delta]c values are averaged over 1 year to 
create an annual average; the annual average [Delta]c is compared to 
the action level.
---------------------------------------------------------------------------

    Section III.G.1 of this preamble provides a more detailed 
discussion of the effective and compliance dates for the requirements 
we are finalizing in this action for the HON and the P&R I NESHAP. 
Section IV.B.3 of this preamble provides a summary of key comments we 
received on the CAA section 112(d)(6) provisions and our responses.
2. NSPS
    The EPA is finalizing, as proposed, a determination that the BSER 
for reducing VOC emissions from SOCMI air oxidation units, distillation 
operations, and reactor processes remains combustion (e.g., 
incineration, flares), and we are also maintaining that the standard of 
performance of 98

[[Page 42950]]

percent reduction of TOC (minus methane and ethane), or reduction of 
TOC (minus methane and ethane) to an outlet concentration of 20 ppmv on 
a dry basis corrected to 3 percent oxygen, continues to reflect the 
BSER for NSPS subparts IIIa, NNNa, and RRRa. While we are finalizing no 
changes in the BSER for reducing VOC emissions from SOCMI air oxidation 
units, distillation operations, and reactor processes, we determined 
that there are certain advances in process operations that were not 
identified or considered during development of the original NSPS 
subparts III, NNN, and RRR (for SOCMI air oxidation units, distillation 
operations, and reactor processes, respectively), which warrant 
revisions to the requirements for process vents in the SOCMI source 
category. Therefore, pursuant to CAA section 111(b)(1)(B), we are 
finalizing revised process vent requirements in new NSPS subparts IIIa, 
NNNa, and RRRa (for SOCMI air oxidation unit processes, distillation 
operations, and reactor processes for which construction, 
reconstruction, or modification commenced after April 25, 2023), 
consistent with the proposed rule (88 FR 25080, April 25, 2023). In 
particular, we are finalizing for NSPS subparts IIIa, NNNa and RRRa, as 
proposed, the removal of the entire TRE concept (including the removal 
of the alternative of maintaining a TRE index value greater than 1 
without the use of control device and the limited applicability 
exemptions) such that owners and operators of affected facilities (for 
which construction, reconstruction, or modification commences after 
April 25, 2023) are required to reduce emissions of TOC (minus methane 
and ethane) from all vent streams of an affected facility by 98 percent 
by weight or to a concentration of 20 ppmv on a dry basis corrected to 
3 percent oxygen, or combust the emissions in a flare. The EPA is also 
finalizing, as proposed, that affected sources that combust the 
emissions in a flare meet the same operating and monitoring 
requirements for flares that we are finalizing for flares subject to 
the HON. However, based on comments received on the proposed 
rulemaking, we are finalizing a mass-based exemption criteria of 0.001 
lb/hr TOC (for which emission controls are not required) in new NSPS 
subparts IIIa and NNNa. Also, as proposed, we are not including in the 
final NSPS subparts IIIa, NNNa, and RRRa a relief valve discharge 
exemption in the definition of ``vent stream''; instead, any relief 
valve discharge to the atmosphere of a vent stream is a violation of 
the emissions standard. In addition, we are finalizing, as proposed, 
the same work practice standards for maintenance vents that we are 
finalizing for HON process vents, and, as proposed, the same monitoring 
requirements that we are finalizing for HON process vents for adsorbers 
that cannot be regenerated and regenerative adsorbers that are 
regenerated offsite.
    For equipment leaks, we determined that there are techniques used 
in practice related to LDAR of certain equipment that achieve greater 
emission reductions than those currently required by NSPS subpart VVa. 
Therefore, pursuant to the requirements of CAA section 111(b)(1)(B), we 
are finalizing revised equipment leak requirements in new NSPS subpart 
VVb (for facilities that commence construction, reconstruction, or 
modification after April 25, 2023), consistent with the proposed rule 
(88 FR 25080, April 25, 2023). We are finalizing that BSER for gas and 
light liquid valves is the same monitoring in an LDAR program as NSPS 
subpart VVa, but now at a leak definition of 100 ppm, and BSER for 
connectors is monitoring in the LDAR program at a leak definition of 
500 ppm and monitored annually, with reduced frequency for good 
performance. In a change from the proposed rule, we are finalizing a 
definition of ``capital expenditure'' in NSPS subpart VVb to use a 
formula that better reflects the trajectory of inflation.
    Section IV.B.3 of this preamble provides a summary of key comments 
we received on the proposed provisions pursuant to CAA section 
111(b)(1)(B) and our responses.

C. What are the final rule amendments pursuant to CAA sections 
112(d)(2) and (3), and 112(h) for the SOCMI, P&R I, and P&R II source 
categories?

    Consistent with Sierra Club v. EPA 551 F. 3d 1019 (D.C. Cir. 2008) 
and the April 25, 2023, proposal (88 FR 25080), we are revising 
monitoring and operational requirements for flares to ensure HON and 
P&R I flares meet the MACT standards at all times when controlling HAP 
emissions.\28\ See 40 CFR 63.108 (for HON) and 40 CFR 63.508 (for the 
P&R I NESHAP). In addition, we are finalizing provisions and 
clarifications as proposed for periods of SSM and bypasses, including:
---------------------------------------------------------------------------

    \28\ P&R II sources do not use flares as APCDs as they are 
making resins from chlorinated chemicals (i.e., epichlorohydrin 
feedstocks), and chlorinated chemicals are not controlled with 
flares.
---------------------------------------------------------------------------

     PRD releases (see 40 CFR 63.165(e) (for HON) and 40 CFR 
63.502(a) (for the P&R I NESHAP));
     bypass lines on closed vent systems (see 40 CFR 
63.114(d)(3), 40 CFR 63.118(a)(5), 40 CFR 63.127(d)(3), 40 CFR 
63.130(a)(2)(iv), (b)(3), and (d)(7), and 40 CFR 63.148(f)(4), 
(i)(3)(iii), and (j)(4) (for HON and the P&R I NESHAP) as well as 40 
CFR 63.480(d)(3), 40 CFR 63.491(e)(6), 40 CFR 63.497(d)(3), and 
63.498(d)(5)(v) (for the P&R I NESHAP));
     maintenance vents and equipment openings (excluding 
storage vessel degassing) (see 40 CFR 63.113(k) (for HON) 40 CFR 
63.485(x) and 40 CFR 63.487(i) (for the P&R I NESHAP));
     storage vessel degassing (see 40 CFR 63.119(a)(2) (for 
HON) and 40 CFR 63.484(a) (for the P&R I NESHAP)); and
     planned routine maintenance for storage vessels (see 40 
CFR 63.119(e)(3) through (5) (for HON) and 40 CFR 63.484(a) (for the 
P&R I NESHAP)).
    However, in response to comments received on the proposed 
rulemaking for storage vessel degassing, we are: (1) Clarifying in the 
final rule at 40 CFR 63.119(a)(6) that the storage vessel degassing 
work practice standard applies to all Group 1 storage vessels, 
including storage vessels in EtO service, and (2) revising the storage 
vessel degassing work practice standard in the final rule at 40 CFR 
63.119(a)(6) to allow storage vessels to be vented to the atmosphere 
once a storage vessel degassing organic HAP concentration of 5,000 ppmv 
as methane is met, or until the vapor space concentration is less than 
10 percent of the LEL. In addition, in response to comments received on 
the proposed rulemaking for planned routine maintenance of storage 
vessels, we are clarifying in the final rule at 40 CFR 63.119(f)(3) 
that the 240-hour planned routine maintenance provisions also apply for 
breathing losses for fixed rood roof vessels routed to a fuel gas 
system or to a process.
    To address regulatory gaps, we are also finalizing the emission 
limits as proposed for polychlorinated dibenzo-p-dioxins (dioxins) and 
polychlorinated dibenzofurans (furans) for HON, P&R I, and P&R II 
facilities (see 40 CFR 63.113(a)(5) (for HON), 40 CFR 63.485(x) and 40 
CFR 63.487(a)(3) and (b)(3) (for the P&R I NESHAP), and 40 CFR 
63.523(e), 40 CFR 63.524(a)(3), and 40 CFR 63.524(b)(3) (for the P&R II 
NESHAP)). We are also finalizing the requirements as proposed for 
transfer operations (see 40 CFR 63.101 (for HON)), heat exchange 
systems (40 CFR 63.523(d) and 40 CFR 63.524(c) (for the P&R II 
NESHAP)), and WSR sources and equipment leaks (see 40 CFR 63.524(a)(3) 
and (b)(3) (for the P&R II NESHAP)). In addition, we are finalizing the 
requirements as proposed for pressure vessels (see 40 CFR 63.119(a)(7) 
(for HON) and 40 CFR 63.484(t) (for the P&R I NESHAP)), surge

[[Page 42951]]

control and bottoms receivers (see 40 CFR 63.170(b) (for HON) and 40 
CFR 63.485(d) (for the P&R I NESHAP)), but with a few changes in the 
final rule in response to persuasive comments received during the 
public comment period.
    In response to comments received on the proposed rulemaking for 
pressure vessels, we are:
     clarifying that the pressure vessel requirements at 40 CFR 
63.119(a)(7) only apply to pressure vessels that are considered Group 1 
storage vessels;
     clarifying that if the equipment is not a connector, gas/
vapor or light liquid valve, light liquid pump, or PRD in ETO service 
and the equipment is on a pressure vessel located at a HON or P&R I 
facility, then that particular equipment is not subject to HON subpart 
H, but rather the equipment is subject to the pressure vessel 
requirements we proposed and are finalizing in 40 CFR 63.119(a)(7);
     clarifying that unsafe and difficult/inaccessible to 
monitor provisions in 40 CFR 63.168(h) and (i) (for valves in gas/vapor 
service and in light liquid service) and in 40 CFR 63.174(f) and (h) 
(for connectors in gas/vapor service and in light liquid service) still 
apply to valves and connectors when complying with 40 CFR 63.119(a)(7); 
and
     replacing the word ``deviation'' with ``violation'' in the 
final rule text at 40 CFR 63.119(a)(7).
    In response to comments received on the proposed rulemaking for 
surge control and bottoms receivers, we are adding language in the 
``C'' and ``Q'' terms of the equations at 40 CFR 63.115(g)(3)(ii) and 
(g)(4)(iv) to allow the use of engineering calculations to determine 
concentration or flow rate only in situations where measurements cannot 
be taken with EPA reference methods. We are also adding reference 
methods for measuring flow rate at 40 CFR 63.115(g)(3)(ii) and 40 CFR 
63.115(g)(4)(iv).
    Finally, we are finalizing, as proposed, that owners and operators 
that use a sweep, purge, or inert blanket between the IFR and fixed 
roof of a storage vessel are required to route emissions through a 
closed vent system and control device (see 40 CFR 63.119(b)(7)). 
However, based on comments received on the proposed rulemaking, we are 
clarifying in the final rule that 40 CFR 63.119(b)(7) applies only if a 
continuous sweep, purge, or inert blanket is used between the IFR and 
fixed roof that causes a pressure/vacuum vent to remain continuously 
open to the atmosphere where uncontrolled emissions are greater than or 
equal to 1.0 lb/hr of total organic HAP.
    Section IV.C.3 of this preamble provides a summary of key comments 
we received on the CAA sections 112(d)(2), (d)(3), and (h) provisions 
and our responses.

D. What are the final rule amendments addressing emissions during 
periods of SSM?

1. NESHAP
    We are finalizing the proposed amendments to the HON and the P&R I 
and P&R II NESHAP to remove and revise provisions related to SSM. In 
its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 
2008), the Court vacated portions of two provisions in the EPA's CAA 
section 112 regulations governing the emissions of HAP during periods 
of SSM. Specifically, the Court vacated the SSM exemptions contained in 
40 CFR 63.6(f)(1) and (h)(1), holding that under section 302(k) of the 
CAA, emissions standards or limitations must be continuous in nature, 
and that the SSM exemptions violated the CAA's requirement that some 
CAA section 112 standards apply at all times. We are finalizing, as 
proposed, a requirement that the standards apply at all times (see 40 
CFR 63.102(e) (for HON) and 40 CFR.525(j) (for the P&R II NESHAP)), 
consistent with the Sierra Club decision. We determined that facilities 
in the SOCMI and P&R II source categories can meet the applicable MACT 
standards at all times, including periods of startup and shutdown. We 
note that on April 21, 2011 (see 77 FR 22566), the EPA finalized 
amendments to eliminate the SSM exemption in the P&R I NESHAP; however, 
for consistency with the SSM-related amendments that we are finalizing 
for the HON and the P&R II NESHAP, we are also finalizing, as proposed, 
additional amendments to the P&R I NESHAP related to the SSM exemption 
that were not addressed in the April 21, 2011, P&R I rule.
    As discussed in the proposal preamble, the EPA interprets CAA 
section 112 as not requiring emissions that occur during periods of 
malfunction to be factored into development of CAA section 112 
standards, although the EPA has the discretion to set standards for 
malfunction periods where feasible. Where appropriate, and as discussed 
in section III.C of this preamble, we are also finalizing alternative 
standards for certain emission points during periods of SSM to ensure a 
CAA section 112 standard applies ``at all times.'' Other than for those 
specific emission points discussed in section III.C of this preamble, 
the EPA determined that no additional standards are needed to address 
emissions during periods of SSM and that facilities in the SOCMI and 
P&R II source categories can meet the applicable MACT standards at all 
times, including periods of startup and shutdown.
    We are also finalizing, as proposed, revisions to the HON and P&R 
II General Provisions tables (Table 3 to subpart F of part 63 and Table 
1 to subpart W of part 63, respectively) to eliminate requirements that 
include rule language providing an exemption for periods of SSM. We 
note that the EPA already made a similar revision to the General 
Provisions table to the P&R I NESHAP (see 77 FR 22566, April 21, 2011). 
Additionally, we are finalizing our proposal to eliminate language 
related to SSM that treats periods of startup and shutdown the same as 
periods of malfunction. Finally, we are finalizing our proposal to 
revise reporting and recordkeeping requirements for deviations as they 
relate to exemptions for periods of SSM. These revisions are consistent 
with the requirement in 40 CFR 63.102(e) and 40 CFR.525(j) that the 
standards apply at all times. We are also finalizing, as proposed, a 
revision to the performance testing requirements. The final performance 
testing provisions prohibit performance testing during SSM because 
these conditions are not representative of normal operating conditions. 
The final rule also requires, as proposed, that operators maintain 
records to document that operating conditions during the test represent 
normal operations. In light of NRDC v. EPA, 749 F.3d 1055 (D.C. Cir., 
2014) (vacating affirmative defense provisions in the CAA section 112 
rule establishing emission standards for Portland cement kilns), the 
EPA is also removing, as proposed, all of the regulatory affirmative 
defense provisions from the P&R I NESHAP at 40 CFR 480(j)(4) in its 
entirety and all other rule text that references these provisions 
(i.e., the definition of affirmative defense in 40 CFR 63.482(b) and 
the reference to ``Sec.  [thinsp]63.480(j)(4)'' in 40 CFR 
63.506(b)(1)(i)(A) and (b)(1)(i)(B)); and we did not receive any 
comments in opposition to these amendments.
    The legal rationale and detailed revisions for SSM periods and the 
affirmative defense provision that we are finalizing here are set forth 
in the proposal preamble (see 88 FR 25080, April 25, 2023).
2. NSPS
    The EPA has determined the reasoning in the court's decision in 
Sierra Club applies equally to CAA

[[Page 42952]]

section 111 because the definition of ``emission'' or ``standard'' in 
CAA section 302(k), and the embedded requirement for continuous 
standards, also applies to the NSPS.\29\ Therefore, we are finalizing, 
as proposed, standards in NSPS subparts VVb, IIIa, NNNa, and RRRa that 
apply at all times, and more specifically during periods of SSM. The 
NSPS general provisions in 40 CFR 60.8(c) currently exempt non-opacity 
emission standards during periods of SSM. We are finalizing, as 
proposed, specific requirements in NSPS subparts IIIa, NNNa, and RRRa 
that override the general provisions for SSM (see 40 CFR 60.612a, 40 
CFR 60.662a, and 40 CFR 60.702a, respectively).
---------------------------------------------------------------------------

    \29\ See, e.g., 88 FR 11556 (Feb. 23, 2023) (removing SSM 
exemptions from NSPS for lead acid battery manufacturing plants); 88 
FR 80594 (Nov. 20, 2023) (removing SSM exemptions from NSPS for 
secondary lead smelters); 77 FR 49490 (Aug. 16, 2012) (removing SSM 
exemptions from NSPS for oil and natural gas sector).
---------------------------------------------------------------------------

E. What are the final amendments addressing the NSPS Subparts VV and 
VVa reconsideration?

    In response to the January 2008 petition for reconsideration, we 
are finalizing, as proposed: (1) Definitions for ``process unit'' for 
NSPS subparts VV and VVa; (2) removal of the requirements in 40 CFR 
60.482-1(g) (for NSPS subpart VV) and 40 CFR 60.482-1a(g) (for NSPS 
subpart VVa) that are related to a method for assigning shared storage 
vessels to specific process units; and (3) removal of the connector 
monitoring provisions from NSPS subpart VVa at 40 CFR 60.482-11a in 
their entirety. However, based on comments received on the proposed 
rulemaking, we are revising the value of ``X'' in the capital 
expenditure equation of NSPS subpart VVa to correct an erroneous 
phrasing that attached the value of ``X'' in the percent Y equation to 
the date of construction, reconstruction and modification (as opposed 
to date of physical or operational change). In the final rule, we have 
revised the ``capital expenditure'' definition in NSPS subpart VVa at 
40 CFR 60.481a such that for owners or operators that made a physical 
or operational change to their existing facility prior to November 16, 
2007, the percent Y is determined from the following equation: Y = 1.0 
- 0.575 log X, where the value of ``X'' is 1982 minus the year of 
construction, and for owners or operators that made a physical or 
operational change to their existing facility on or after November 16, 
2007, the percent Y is determined from the following equation: Y = 1.0 
- 0.575 log X, where the value of ``X'' is 2006 minus the year of 
construction. Section IV.E.3 of this preamble provides a summary of key 
comments we received on the NSPS subparts VV and VVa reconsideration 
issues and our responses.

F. What other changes have been made to the NESHAP and NSPS?

    This rule also finalizes, as proposed, revisions to several other 
NESHAP and NSPS requirements. We describe these revisions in this 
section as well as other proposed provisions that have changed since 
proposal.
    To increase the ease and efficiency of data submittal and data 
accessibility, we are finalizing, as proposed, a requirement that 
owners or operators submit electronic copies of certain required 
performance test reports, flare management plans, and periodic reports 
(including fenceline monitoring reports for HON and the P&R I NESHAP) 
through the EPA's Central Data Exchange (CDX) using the Compliance and 
Emissions Data Reporting Interface (CEDRI) (see 40 CFR 63.108(e), 40 
CFR 63.152(c) and (h), and 40 CFR 63.182(d) and (e) (for HON), 40 CFR 
63.506(e)(6), and (i)(3) (for the P&R I NESHAP), and 40 CFR 63.528(a) 
and (d) (for the P&R II NESHAP), 40 CFR 60.486(l), and 60.487(a) and 
(g) through (i) (for NSPS subpart VV), 40 CFR 60.486a(l), and 
60.487a(a) and (g) through (i) (for NSPS subpart VVa), 40 CFR 
60.486b(l), and 60.487b(a) and (g) through (i) (for NSPS subpart VVb), 
40 CFR 60.615(b), (j), (k), and (m) through (o) (for NSPS subpart III), 
40 CFR 60.615a(b), (h) through (l), and (n), and 40 CFR 619a(e) (for 
NSPS subpart IIIa), 40 CFR 60.665(b), (l), (m), and (q) through (s) 
(for NSPS subpart NNN), 40 CFR 60.665a(b), (h), (k) through (n), and 
(p), and 40 CFR 669a(e) (for NSPS subpart NNNa), 40 CFR 60.705(b), (l), 
(m), and (u) through (w) (for NSPS subpart RRR), and 40 CFR 60.705a(b), 
(k) through (o), and (v), and 40 CFR 709a(e) (for NSPS subpart RRRa)). 
A description of the electronic data submission process is provided in 
the memorandum, Electronic Reporting Requirements for New Source 
Performance Standards (NSPS) and National Emission Standards for 
Hazardous Air Pollutants (NESHAP) Rules (see Docket Item No. EPA-HQ-
OAR-2022-0730-0002). The final rule requires that performance test 
results collected using test methods that are supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the ERT website \30\ at 
the time of the test be submitted in the format generated through the 
use of the ERT or an electronic file consistent with the xml schema on 
the ERT website, and other performance test results be submitted in 
portable document format (PDF) using the attachment module of the ERT. 
For periodic reports (including fenceline monitoring reports), the 
final rule requires that owners or operators use the appropriate 
spreadsheet template to submit information to CEDRI. We have made minor 
clarifying edits to the spreadsheet templates based on comments 
received during the public comment period. The final version of the 
templates for these reports are located on the CEDRI website.\31\ The 
final rule requires that flare management plans be submitted as a PDF 
upload in CEDRI. Furthermore, we are finalizing, as proposed, 
provisions in the NSPS that allow facility operators the ability to 
seek extensions for submitting electronic reports for circumstances 
beyond the control of the facility, i.e., for a possible outage in the 
CDX or CEDRI or for a force majeure event in the time just prior to a 
report's due date, as well as the process to assert such a claim. For a 
more detailed discussion of these final amendments, see section III.E.3 
of the proposal preamble (see 88 FR 25080, April 25, 2023), as well as 
sections IV.F and VI.B of this preamble.
---------------------------------------------------------------------------

    \30\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
    \31\ https://www.epa.gov/electronic-reporting-air-emissions/cedri.
---------------------------------------------------------------------------

    Also, we are finalizing, as proposed, the restructuring of all HON 
definitions from NESHAP subparts G and H (i.e., 40 CFR 63.111 and 40 
CFR 63.161, respectively) into the definition section of NESHAP subpart 
F (i.e., 40 CFR 63.101). To consolidate differences between certain 
definitions in these subparts, we are also finalizing the amendments we 
proposed in Table 30 of the proposal preamble (88 FR 25080, April 25, 
2023), with only minor changes based on comments received on the 
proposed rulemaking. The comments and our specific responses to these 
items can be found in the document titled Summary of Public Comments 
and Responses for New Source Performance Standards for the Synthetic 
Organic Chemical Manufacturing Industry and National Emission Standards 
for Hazardous Air Pollutants for the Synthetic Organic Chemical 
Manufacturing Industry and Group I & II Polymers and Resins Industry, 
which is available in the docket for this rulemaking.
    In addition, we are finalizing requirements, as proposed, at 40 CFR 
63.114(a)(5)(v), 40 CFR 63.120(d)(1)(iii), 40 CFR 63.127(b)(4), and 40 
CFR

[[Page 42953]]

63.139(d)(5) (for HON), and 40 CFR 63.484(t), 40 CFR 63.485(x), and 40 
CFR 63.489(b)(10) (for the P&R I NESHAP) for owners or operators using 
adsorbers that cannot be regenerated and regenerative adsorbers that 
are regenerated offsite to use dual (two or more) adsorbent beds in 
series and conduct monitoring of HAP or TOC on the outlet of the first 
adsorber bed in series using a sample port and a portable analyzer or 
chromatographic analysis. However, we have clarified in the proposed 
rule text in this final action that the monitoring plan provisions in 
40 CFR 63.120(d)(2) and (3) do not apply to HON sources subject to the 
monitoring provisions in 40 CFR 63.120(d)(1)(iii); and the monitoring 
plan provisions in 40 CFR 63.120(d)(2) and (3) do not apply to P&R I 
sources subject to the monitoring provisions in 40 CFR 
63.120(d)(1)(iii) (via 40 CFR 63.484(t) and 40 CFR 63.485(x)). The 
comments and our specific responses to these items can be found in the 
document titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking.
    We are also finalizing, as proposed, several corrections to the 
calibration drift assessment requirements in NSPS subpart VVa at 40 CFR 
60.485a(b)(2). These amendments include: (1) Correcting a regulatory 
citation to read ``Sec.  60.486a(e)(8)'' instead of ``Sec.  
60.486a(e)(7)''; (2) removing the extraneous sentence ``Calculate the 
average algebraic difference between the three meter readings and the 
most recent readings and the most recent calibration value.''; (3) 
providing clarity in the mathematical step of the assessment by 
replacing the sentence ``Divide this algebraic difference by the 
initial calibration value and multiply by 100 to express the 
calibration drift as a percentage.'' with ``Divide the arithmetic 
difference of the initial and post-test calibration response by the 
corresponding calibration gas value for each scale and multiply by 100 
to express the calibration drift as a percentage.''; and (4) providing 
clarity by making other minor textural changes to the provisions 
related to the procedures for when a calibration drift assessment shows 
negative or positive drift of more than 10 percent. We did not receive 
any comments in opposition of these amendments.
    In addition, we are finalizing, as proposed, the requirement in the 
HON and the P&R I and P&R II NESHAP, and NSPS subparts IIIa, NNNa, and 
RRRa to conduct subsequent performance testing on non-flare control 
devices no later than 60 calendar months after the previous performance 
test. The comments and our specific response to this item can be found 
in the document titled Summary of Public Comments and Responses for New 
Source Performance Standards for the Synthetic Organic Chemical 
Manufacturing Industry and National Emission Standards for Hazardous 
Air Pollutants for the Synthetic Organic Chemical Manufacturing 
Industry and Group I & II Polymers and Resins Industry, which is 
available in the docket for this rulemaking.
    Also, we are finalizing, as proposed to: (1) Remove the provisions 
that allow compliance with certain portions of 40 CFR part 264, subpart 
AA or CC in lieu of portions of NESHAP subpart G (see 40 CFR 
63.110(h)); and (2) remove the provisions that allow compliance with 
certain portions of 40 CFR part 65 in lieu of portions of NESHAP 
subparts G and H (see 40 CFR 63.110(i) and 40 CFR 60.160(g)). In 
addition, based on comments received on the proposed rulemaking, we 
are: (1) Revising 40 CFR 63.160(b)(1) and (c)(1) in the final rule such 
that compliance with HON subpart H constitutes compliance with NSPS 
subpart VVa provided the owner or operator continues to comply with 40 
CFR 60.480a(e)(2)(i); and (2) revising 40 CFR 63.160(b)(1) and (c)(1) 
in the final rule such that compliance with HON subpart H constitutes 
compliance with NSPS subpart VVb provided the owner or operator 
continues to comply with 40 CFR 60.480b(e)(2)(i). We have also revised 
40 CFR 60.480b(e)(2)(i) in the final rule to require compliance with 40 
CFR 60.482-7b (i.e., the standards for gas and light liquid valves in 
NSPS subpart VVb) in addition to the requirements of 40 CFR 60.485b(d), 
(e), and (f), and 40 CFR 60.486b(i) and (j). The comments and our 
specific responses to these items can be found in the document titled 
Summary of Public Comments and Responses for New Source Performance 
Standards for the Synthetic Organic Chemical Manufacturing Industry and 
National Emission Standards for Hazardous Air Pollutants for the 
Synthetic Organic Chemical Manufacturing Industry and Group I & II 
Polymers and Resins Industry, which is available in the docket for this 
rulemaking.
    Finally, we are finalizing all of the revisions that we proposed 
for clarifying text or correcting typographical errors, grammatical 
errors, and cross-reference errors. These editorial corrections and 
clarifications are discussed in section III.E.5.f of the proposal 
preamble (see 88 FR 25080, April 25, 2023). We are also including 
several additional minor clarifying edits in the final rule based on 
comments received during the public comment period. The comments and 
our specific responses to these items can be found in the document 
titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking.

G. What are the effective and compliance dates of the standards?

1. HON and the P&R I and P&R II NESHAP
    For all of the requirements we are finalizing under CAA sections 
112(d)(2), (3), and (6), and 112(h) (except for the removal of 
affirmative defense provisions in the P&R I NESHAP and fenceline 
monitoring requirements in HON and the P&R I NESHAP), all existing 
affected sources and all affected sources that were new sources under 
the previous HON and P&R I NESHAP (i.e., sources that commenced 
construction or reconstruction after December 31, 1992 (for HON) or 
after June 12, 1995 (for the P&R I NESHAP), and on or before April 25, 
2023), must comply with all of the amendments no later than July 15, 
2027, or upon startup, whichever is later. For existing sources, CAA 
section 112(i) provides that the compliance date for standards 
promulgated under section 112(d) shall be as expeditious as 
practicable, but no later than 3 years after the effective date of the 
standard. Association of Battery Recyclers v. EPA, 716 F.3d 667, 672 
(D.C. Cir. 2013) (``Section 112(i)(3)'s three-year maximum compliance 
period applies generally to any emission standard . . . promulgated 
under [section 112].''). We agree with the commenters (see section 11.1 
of the document titled Summary of Public Comments and Responses for New 
Source Performance Standards for the Synthetic Organic Chemical 
Manufacturing Industry and National Emission Standards for Hazardous 
Air Pollutants for the Synthetic Organic Chemical Manufacturing 
Industry and

[[Page 42954]]

Group I & II Polymers and Resins Industry, which is available in the 
docket for this rulemaking) that 3 years is needed for owners and 
operators to implement the requirements we are finalizing under CAA 
sections 112(d)(2), (3), and (6). For example, for process vents, if an 
affected source has uncontrolled process vents that emit greater than 
or equal to 1.0 lb/hr of total organic HAP, then a new control system, 
such as a thermal oxidizer with piping, ductwork, etc., may need to be 
installed (due to the removal of the TRE concept in its entirety in the 
final rule). Also, additional permits (e.g., New Source Review and/or a 
Title V permit modifications) may be required for new emission control 
equipment. Moreover, 3 years is needed to understand the final rule 
changes; revise site guidance and compliance programs; ensure 
operations can meet the standards during startup and shutdown; update 
operation, maintenance, and monitoring plans; upgrade emission capture 
and control systems; install new flare monitoring equipment; and 
install new process control systems. As provided in CAA section 112(i) 
and 5 U.S.C. 801(3), all new affected sources that commenced 
construction or reconstruction after April 25, 2023, are required to 
comply with all requirements under CAA sections 112(d)(2), (3), (6), 
and 112(h) (including fenceline monitoring) by July 15, 2024 or upon 
startup, whichever is later. We are also finalizing, as proposed, that 
owners or operators of P&R I affected sources must comply with the 
removal of the affirmative defense provisions 60 days after the 
publication date of the final rule (or upon startup, whichever is 
later). We provided additional rationale for these compliance dates in 
the preamble to the proposed rule (88 FR 25080, April 25, 2023).
    In a change from the proposed rule, we have extended the compliance 
date for fenceline monitoring (with the exception of fenceline 
monitoring of chloroprene at P&R I affected sources producing neoprene, 
which is discussed later in this section) from 1 to 2 years. Owners and 
operators of all existing sources, and all affected sources that were 
new under the current rules--i.e., sources that commenced construction 
or reconstruction after December 31, 1992 (for HON) or after June 12, 
1995 (for the P&R I NESHAP), and on or before April 25, 2023--must 
begin fenceline monitoring 2 years after the effective date of the 
final rule and, starting 3 years after the effective date of the final 
rule, must perform root cause analysis and apply corrective action 
requirements upon exceedance of an annual average concentration action 
level. We extended the timeline for fenceline monitoring from 1 to 2 
years based on comments received, which indicated that EPA Method 327 
will require laboratories to increase their capacity to meet the 
requirements for fenceline monitoring. We consider this expanded 
timeline to be necessary to allow commercial labs to conduct the needed 
method development, expand capacity, and develop the logistics needed 
to meet the requirements in the final rule. We also agree with 
commenters' other assertions that more time is needed to read and 
assess the new fenceline monitoring requirements; prepare sampling and 
analysis plans; develop and submit site-specific monitoring plans; 
identify representative, accessible, and secure monitoring locations 
for offsite monitors and obtain permission from the property owner to 
both place and routinely access the monitors; make any necessary 
physical improvements to fencelines to be able to site monitors, 
including construction of access roads, physical fencing, and potential 
drainage improvements; and obtain approval of any necessary capital 
expenditures. We consider 2 years to be necessary to allow for all of 
these things. For additional details, see section 11.1 of the document 
titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking.
    For all of the requirements we are finalizing under CAA sections 
112(f) for the HON, we are finalizing as proposed, except we are 
clarifying that the compliance dates we proposed are from the effective 
date of the rule rather than the publication date of the proposal. In 
other words, all existing affected sources and all affected sources 
that were new sources under the previous HON (i.e., sources that 
commenced construction or reconstruction after December 31, 1992, and 
on or before April 25, 2023) must comply with the EtO requirements no 
later than July 15, 2026, or upon startup, whichever is later. As 
explained in the April 25, 2023, proposed rule (88 FR 25080, 25176), 
CAA section 112(f)(4) prescribes the compliance date for emission 
standards issued under CAA section 112(f). Ass'n of Battery Recyclers 
v. EPA, 716 F.3d 667, 672 (D.C. Cir. 2013) (``[S]ection 112(f)(4)'s 
two-year maximum applies more specifically to standards `under this 
subsection,' i.e., section 112(f).''). For existing sources, the 
earliest compliance date for CAA section 112(f) standards is 90 days. 
However, the compliance period can be extended up to 2 years if the EPA 
finds that more time is needed for the installation of controls. 42 
U.S.C. 7412(f)(4)(B). The EPA finds that the new EtO provisions under 
CAA section 112(f) will require additional time to plan, purchase, and 
install emission control equipment. For example, for process vents, if 
an affected source cannot demonstrate 99.9-percent control of EtO 
emissions, or reduce EtO emissions to less than 1 ppmv (from each 
process vent) or 5 pounds per year (for all combined process vents), 
then a new control system, such as a scrubber with piping, ductwork, 
feed tanks, etc., may need to be installed. Similarly, this same 
scenario (i.e., installation of a new control system, such as a 
scrubber with piping, ductwork, feed tanks, etc) may be necessary for 
storage vessels in order to reduce EtO emissions by greater than or 
equal to 99.9 percent by weight or to a concentration less than 1 ppmv. 
Likewise, a new steam stripper may be needed control wastewater with a 
total annual average concentration of EtO greater than or equal to 1 
ppmw. Additionally, we agree with commenters (see section 11.1 of the 
document titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking) that additional permits may be required for these new 
emission control equipment (e.g., New Source Review and/or a Title V 
permit modifications). In other words, sufficient time is needed to 
properly engineer the project, obtain capital authorization and 
funding, procure the equipment, obtain permits, and construct and 
start-up the equipment. Therefore, we are finalizing a compliance date 
of 2 years after the effective date of the final rule for all existing 
affected sources to meet the EtO requirements. All new affected sources 
that commence construction or reconstruction after April 25, 2023, are 
required to comply with the EtO requirements for the HON by July 15, 
2024 or upon startup, whichever is later.

[[Page 42955]]

This compliance schedule is consistent with the compliance deadlines 
outlined in the CAA under section 112(f)(4) and the CRA. We provided 
additional rationale for these compliance dates in the preamble to the 
proposed rule (88 FR 25080, April 25, 2023).
    In a change from the proposed rule, the EPA is shortening the 
compliance deadline for affected sources producing neoprene, due to the 
EPA's finding that chloroprene emissions from the only such source pose 
an imminent and substantial endangerment under CAA section 303, 42 
U.S.C. 7603. United States v. Denka Performance Elastomer, LLC, et al., 
No. 2:23-cv-00735 (E.D. La. filed Feb. 28, 2023). All existing affected 
sources producing neoprene and all affected sources producing neoprene 
that were new sources under the previous P&R I NESHAP (i.e., sources 
that commenced construction or reconstruction after June 12, 1995, and 
on or before April 25, 2023) must comply with the chloroprene 
requirements we are finalizing under CAA section 112(f) for the P&R I 
NESHAP (see sections III.B.1 and IV.A.3.e of this preamble for a 
details about these chloroprene requirements) no later than October 15, 
2024,\32\ or upon startup, whichever is later. However, such sources 
may seek the EPA's approval of a waiver from the 90-day compliance 
deadline and obtain a compliance date of up to July 15, 2026 if they 
demonstrate to the Administrator's satisfaction that ``such period is 
necessary for the installation of controls'' and that steps will be 
taken during the waiver period to assure that the public health of 
persons will be protected from any imminent endangerment. See 42 U.S.C. 
112(f)(4)(B); 40 CFR 63.6(i)(4)(ii).\33\
---------------------------------------------------------------------------

    \32\ The compliance date is 90 days after the effective date of 
this final action due to the Congressional Review Act.
    \33\ We are revising the General Provisions table to the P&R II 
NESHAP entry for 40 CFR 63.6(e)(1)(i) by changing the ``No'' to 
``Yes'' for affected sources producing neoprene. EPA is also 
retaining authority to grant or deny requests for extensions of the 
compliance date under 40 CFR 63.6(i)(4)(ii) at 40 CFR 63.507(c)(6), 
and is not delegating that authority to states.
---------------------------------------------------------------------------

    All new affected sources that commence construction or 
reconstruction after April 25, 2023, are required to comply with the 
chloroprene requirements for P&R I affected sources producing neoprene 
no later than by July 15, 2024 or upon startup, whichever is later. 
This compliance schedule is consistent with the compliance deadlines 
outlined in the CAA under section 112(f)(4) and the CRA, 5 U.S.C. 801.
2. NSPS Subparts VV, VVa, VVb, III, IIIa, NNN, NNNa, RRR, RRRa
    All sources of equipment leaks in the SOCMI (regulated under NSPS 
subpart VVb) and all SOCMI air oxidation unit processes, distillation 
operations, and reactor processes (regulated under NSPS subparts IIIa, 
NNNa, and RRRa, respectively), that commenced construction, 
reconstruction, or modification on or after April 25, 2023, must meet 
the requirements of the new NSPS upon startup of the new, reconstructed 
or modified facility or by July 15, 2024, whichever is later. This 
compliance schedule is consistent with the requirements in section 111 
of the CAA and the CRA.
    Also, for NSPS subparts VV, VVa, III, NNN, and RRR, we are 
finalizing, as proposed, the change in format of the reporting 
requirements to require electronic reporting (i.e., we are not 
finalizing any new data elements); and owners and operators must begin 
submitting performance test reports electronically beginning on July 
15, 2024 and semiannual reports on and after July 15, 2025 or once the 
report template for the subpart has been available on the CEDRI website 
(https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 
year, whichever date is later. For NSPS subparts IIIa, NNNa, and RRRa, 
we are finalizing, as proposed, that owners and operators must submit 
performance test reports electronically within 60 days after the date 
of completing each performance test, and for NSPS subparts VVb, IIIa, 
NNNa, and RRRa, semiannual reports on and after July 15, 2024 or once 
the report template for the subpart has been available on the CEDRI 
website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) 
for 1 year, whichever date is later.

IV. What is the rationale for our final decisions and amendments for 
the SOCMI, P&R I, and P&R II source categories?

    For each issue, this section provides a description of what we 
proposed and what we are finalizing for the issue, the EPA's rationale 
for the final decisions and amendments, and a summary of key comments 
and responses. For all comments not discussed in this preamble, comment 
summaries and the EPA's responses can be found in the document titled 
Summary of Public Comments and Responses for New Source Performance 
Standards for the Synthetic Organic Chemical Manufacturing Industry and 
National Emission Standards for Hazardous Air Pollutants for the 
Synthetic Organic Chemical Manufacturing Industry and Group I & II 
Polymers and Resins Industry, which is available in the docket for this 
rulemaking.

A. Residual Risk Review for the SOCMI and Neoprene Production Source 
Categories NESHAP

1. What did we propose pursuant to CAA section 112(f) for the SOCMI and 
Neoprene Production source categories?
a. SOCMI Source Category
    Pursuant to CAA section 112(f), the EPA conducted a residual risk 
review and presented the results of this review, along with our 
proposed decisions regarding risk acceptability and ample margin of 
safety, in the April 25, 2023, proposed rule for the SOCMI source 
category subject to HON (88 FR 25080). The results of the risk 
assessment for the proposal are presented briefly in Table 1 of this 
preamble. More detail is in the residual risk technical support 
document, Residual Risk Assessment for the SOCMI Source Category in 
Support of the 2023 Risk and Technology Review Proposed Rule (see 
Docket Item No. EPA-HQ-OAR-2022-0730-0085).

[[Page 42956]]

[GRAPHIC] [TIFF OMITTED] TR16MY24.004

    The results of the proposed chronic baseline inhalation cancer risk 
assessment at proposal indicated that, based on estimates of current 
actual and allowable emissions, the maximum individual lifetime cancer 
risk posed by the source category was 2,000-in-1 million driven by EtO 
emissions from PRDs (74 percent) and equipment leaks (20 percent). At 
proposal, the total estimated cancer incidence from this source 
category was estimated to be 2 excess cancer cases per year. 
Approximately 7.2 million people were estimated to have cancer risks 
above 1-in-1 million from HAP emitted from the facilities in this 
source category. At proposal, the estimated maximum chronic noncancer 
target organ-specific hazard index (TOSHI) for the source category was 
2 for respiratory effects at two different facilities (from maleic 
anhydride emissions at one facility and chlorine emissions at another 
facility).
    As shown in Table 1 of this preamble, the worst-case acute hazard 
quotient (HQ) (based on the reference exposure level (REL)) at proposal 
was 3 based on the RELs for chlorine and acrolein. In addition, at 
proposal, the multipathway risk screening assessment resulted in a 
maximum Tier 3 cancer screening value (SV) of 60 for mercury and 2 for 
cadmium for the fisher scenario, and 20 for polycyclic organic matter 
(POM) for the gardener scenario. At proposal, no site-specific 
assessment using TRIM.FaTE (which incorporates AERMOD deposition, 
enhanced soil/water run-off calculations, and model boundary 
identification) was deemed necessary. The EPA determined that it is not 
necessary to go beyond the Tier 3 lake analysis or conduct a site-
specific assessment for cadmium, mercury, or POM. The EPA compared the 
Tier 3 screening results to site-specific risk estimates for five 
previously assessed source categories and concluded that if the Agency 
was to perform a site-specific assessment for the SOCMI source 
category, the HQ for ingestion exposure, specifically cadmium and 
mercury through fish ingestion, is at or below 1; and for POM, the 
maximum cancer risk under the rural gardener scenario would likely 
decrease to below 1-in-1 million. Also, at proposal, the highest annual 
average lead concentration of 0.004 micrograms per cubic meter ([mu]g/
m\3\) was well below the National Ambient Air Quality Standards (NAAQS) 
for lead, indicating low potential for multipathway risk of concern due 
to lead emissions.
    At proposal, the maximum lifetime individual cancer risk posed by 
the 195 modeled facilities, based on whole-facility emissions, was 
2,000-in-1 million, with EtO emissions from PRDs (74 percent) and 
equipment leaks (20 percent) from SOCMI source category emissions 
driving the risk. Regarding the noncancer risk assessment, the maximum 
chronic noncancer hazard index (HI) posed by whole-facility emissions 
was estimated to be 4 (for respiratory effects) due mostly (98 percent) 
to emissions from 2 facilities.
    We weighed all health risk measures and factors, including those 
shown in Table 1 of this preamble, in our risk acceptability 
determination and proposed that the risks posed by the SOCMI source 
category under the current MACT provisions are unacceptable (section 
III.B of the proposal preamble, 88 FR 25080, April 25, 2023). At 
proposal, we identified EtO as the driver of the unacceptable risk and 
evaluated several options to control EtO emissions from (1) process 
vents, (2) storage vessels, (3) equipment leaks, (4) heat exchange 
systems, and (5) wastewater ``in ethylene oxide service.''

[[Page 42957]]

We also proposed requirements to reduce EtO emissions from maintenance 
vents, flares, and PRDs.
    For process vents, we proposed to define ``in ethylene oxide 
service'' in the HON at 40 CFR 63.101 to mean each process vent in a 
process that, when uncontrolled, contains a concentration of greater 
than or equal to 1 ppmv undiluted EtO, and when combined, the sum of 
all these process vents would emit uncontrolled EtO emissions greater 
than or equal to 5 pounds per year (2.27 kilograms per year).
    For storage vessels of any capacity and vapor pressure, we proposed 
to define ``in ethylene oxide service'' in the HON at 40 CFR 63.101 to 
mean that the concentration of EtO of the stored liquid is at least 0.1 
percent by weight. Additionally, we proposed that unless specified by 
the Administrator, owners and operators may calculate the concentration 
of EtO of the fluid stored in a storage vessel if information specific 
to the fluid stored is available such as concentration data from safety 
data sheets. We also proposed that the exemption for ``vessels storing 
organic liquids that contain organic hazardous air pollutants only as 
impurities'' listed in the definition of ``storage vessel'' at 40 CFR 
63.101 does not apply for storage vessels in EtO service.
    For the EtO equipment leak provisions, we proposed to define ``in 
ethylene oxide service'' in the HON at 40 CFR 63.101 to mean any 
equipment that contains or contacts a fluid (liquid or gas) that is at 
least 0.1 percent by weight of EtO.
    For heat exchange systems, we proposed to define ``in ethylene 
oxide service'' in the HON at 40 CFR 63.101 to mean each heat exchange 
system in a process that cools process fluids (liquid or gas) that are 
0.1 percent or greater by weight of EtO.
    For wastewater, we proposed to define ``in ethylene oxide service'' 
in the HON at 40 CFR 63.101 to mean each wastewater stream that 
contains total annual average concentration of EtO greater than or 
equal to 1 ppmw at any flow rate.
    To reduce risks from process vents in EtO service, we proposed 
requirements at 40 CFR 63.113(j) to reduce emissions of EtO by either 
(1) venting emissions through a closed-vent system to a control device 
that reduces EtO by greater than or equal to 99.9 percent by weight, to 
a concentration less than 1 ppmv for each process vent, or to less than 
5 lb/yr for all combined process vents; or (2) venting emissions 
through a closed-vent system to a flare meeting the flare operating 
requirements discussed in section III.B.4.a.i of the proposal preamble 
(88 FR 25080, April 25, 2023).
    To reduce risks from storage vessels in EtO service, we proposed a 
requirement at 40 CFR 63.119(a)(5) to reduce emissions of EtO by either 
(1) venting emissions through a closed-vent system to a control device 
that reduces EtO by greater than or equal to 99.9 percent by weight or 
to a concentration less than 1 ppmv for each storage vessel vent; or 
(2) venting emissions through a closed-vent system to a flare meeting 
the flare operating requirements discussed in section IV.A.1 of the 
proposal preamble (84 FR 69182, December 17, 2019).
    To reduce risks from equipment leaks in EtO service, we proposed 
the following combined requirements: monitoring of connectors in gas/
vapor and light liquid service at a leak definition of 100 ppm on a 
monthly basis with no reduction in monitoring frequency or delay of 
repair (at 40 CFR 63.174(a)(3) and 40 CFR 63.174(b)(3)(vi)); light 
liquid pump monitoring at a leak definition of 500 ppm monthly (at 40 
CFR 63.163(b)(2)(iv)); and gas/vapor and light liquid valve monitoring 
at a leak definition of 100 ppm monthly with no reduction in monitoring 
frequency or delay of repair (at 40 CFR 63.168(b)(2)(iv) and 40 CFR 
63.168(d)(5)).
    To reduce risks from EtO emissions due to heat exchange system 
leaks, we proposed at 40 CFR 63.104(g)(6) to require weekly monitoring 
for leaks for heat exchange systems in EtO service using the Modified 
El Paso Method, and if a leak is found, we proposed at 40 CFR 
63.104(h)(6) that owners and operators must repair the leak to reduce 
the concentration or mass emissions rate to below the applicable leak 
action level as soon as practicable, but no later than 15 days after 
the sample was collected with no delay of repair allowed.
    To reduce risks from wastewater in EtO service, we proposed at 40 
CFR 63.132(c)(1)(iii) and (d)(1)(ii) that owners and operators of HON 
sources manage and treat any wastewater streams that are ``in ethylene 
oxide service.'' We also proposed at 40 CFR 63.104(k) to prohibit 
owners and operators from injecting water into or disposing of water 
through any heat exchange system in a CMPU meeting the conditions of 40 
CFR 63.100(b)(1) through (3) if the water contains any amount of EtO, 
has been in contact with any process stream containing EtO, or the 
water is considered wastewater as defined in 40 CFR 63.101.
    In addition, we proposed at 40 CFR 63.165(e)(3)(v)(D) that any 
release event from a PRD in EtO service is a violation of the standard 
to ensure that these process vent emissions are controlled and do not 
bypass controls. Also, in order to help reduce EtO risk from the SOCMI 
source category to an acceptable level, we proposed: (1) A requirement 
at 40 CFR 63.113(k)(4) that owners and operators cannot release more 
than 1.0 ton of EtO from all maintenance vents combined in any 
consecutive 12-month period; and (2) a requirement at 40 CFR 63.108(p) 
that owners and operators can send no more than 20 tons of EtO to all 
of their flares combined in any consecutive 12-month period from all 
HON emission sources at a facility.
    After implementation of the proposed controls for: (1) Process 
vents, (2) storage vessels, (3) equipment leaks, (4) heat exchange 
systems, and (5) wastewater ``in ethylene oxide service,'' as well as 
implementation of the proposed requirements to reduce EtO emissions 
from maintenance vents, flares, and PRDs, we proposed that the 
resulting risks would be acceptable for the SOCMI source category. We 
determined at proposal that estimated post-control risks would be 
reduced to 100-in-1 million (down from 2,000-in-1 million) with no 
individuals exposed to risk levels greater than 100-in-1 million from 
HAP emissions from HON processes (see section III.B.2 of the proposal 
preamble, 88 FR 25080, April 25, 2023).
    We then considered whether the existing MACT standards provide an 
ample margin of safety to protect public health and whether, taking 
into consideration costs, energy, safety, and other relevant factors, 
additional standards are required to prevent an adverse environmental 
effect. We noted that the EPA previously made a determination that the 
standards for the SOCMI source category provided an ample margin of 
safety to protect public health, and that the most significant change 
since that determination was the revised 2016 IRIS inhalation URE for 
EtO and new 2010 IRIS inhalation URE for chloroprene. As such, we 
focused our ample margin of safety analysis on cancer risk for EtO and 
chloroprene, since these pollutants, even after application of controls 
needed to get risks to an acceptable level, drive cancer risk and 
cancer incidence (i.e., 60 percent of remaining cancer incidence is 
from EtO) for the SOCMI source category. The ample margin of safety 
analysis for the SOCMI source category identified no other control 
options for EtO beyond those proposed to reduce risks to an acceptable 
level. For chloroprene emissions from HON-subject sources, we 
identified control

[[Page 42958]]

options for equipment leaks and maintenance activities; however, the 
options evaluated were found not to be cost-effective (see sections 
III.C.6 and III.D.4 of the proposal preamble, 88 FR 25080, April 25, 
2023). Therefore, we proposed that the requirements that we proposed to 
achieve acceptable risk would also provide an ample margin of safety to 
protect public health (section III.B.3 of the proposal preamble, 88 FR 
25080, April 25, 2023).
b. Neoprene Production Source Category
    Pursuant to CAA section 112(f), the EPA conducted a residual risk 
review and presented the results of this review, along with our 
proposed decisions regarding risk acceptability and ample margin of 
safety, in the April 25, 2023, proposed rule for the Neoprene 
Production source category subject to the P&R I NESHAP (88 FR 25080). 
The results of the risk assessment for the proposal are presented 
briefly in Table 2 of this preamble. More detail is in the residual 
risk technical support document, Residual Risk Assessment for the 
Polymers & Resins I Neoprene Production Source Category in Support of 
the 2023 Risk and Technology Review Proposed Rule (see Docket Item No. 
EPA-HQ-OAR-2022-0730-0095).
[GRAPHIC] [TIFF OMITTED] TR16MY24.005

    The results of the proposed chronic baseline inhalation cancer risk 
assessment at proposal indicated that, based on estimates of current 
actual and allowable emissions, the MIR posed by the source category 
was 500-in-1 million, driven by chloroprene emissions from maintenance 
vents (67 percent), storage vessels (11 percent), wastewater (8 
percent), and equipment leaks (4 percent). At proposal, the total 
estimated cancer incidence from this source category was estimated to 
be 0.05 excess cancer cases per year, or 1 cancer case every 20 years. 
Approximately 690,000 people were estimated to have cancer risks above 
1-in-1 million from HAP emitted from this source category. At proposal, 
the estimated maximum chronic noncancer TOSHI for the source category 
was 0.05 for respiratory effects from chloroprene emissions.
    As shown in Table 2 of this preamble, the worst-case acute HQ at 
proposal was 0.3 based on the REL for chloroform. In addition, at 
proposal, we did not undertake the three-tier human health risk 
screening assessment that was conducted for the SOCMI source category 
given that we did not identify reported persistent and bioaccumulative 
HAP (PB-HAP) emissions from the Neoprene Production source category. 
Instead, at proposal, we noted that we would expect dioxins likely to 
be formed by combustion controls used to control chlorinated chemicals 
such as chloroprene from this source category and concluded that risk 
from dioxins from the Neoprene Production source category would be 
lower than they are for the SOCMI source category after compliance with 
the proposed dioxin limit occurs. Also, because we did not identify 
reported PB-HAP emissions, we did not undertake the environmental risk 
screening assessment of PB-HAP for the Neoprene Production source 
category; however, we did conduct an environmental risk screening 
assessment for acid gases and concluded that no ecological benchmark 
was exceeded.
    At proposal, the maximum lifetime individual cancer risk posed by 
the one neoprene production facility, based on whole-facility 
emissions, was 600-in-1 million, with chloroprene emissions from 
maintenance vents (66 percent total, 55 percent from neoprene 
production sources and 11 percent from HON sources), storage vessels (9 
percent total, all from neoprene production sources), equipment leaks 
(7 percent total, 3 percent from neoprene production sources and 4 
percent from HON sources), and wastewater (7 percent, all from neoprene 
production sources) driving the risk. Regarding the noncancer risk 
assessment, the maximum chronic noncancer TOSHI posed by whole-facility 
emissions was estimated to be 0.3 (for respiratory effects) due to 
chlorine emissions.
    We weighed all health risk measures and factors, including those 
shown in Table 2 of this preamble, in our risk

[[Page 42959]]

acceptability determination and proposed that the risks posed by the 
Neoprene Production source category under the current MACT provisions 
are unacceptable (section III.B of the proposal preamble, 88 FR 25080, 
April 25, 2023). At proposal, we identified chloroprene as the driver 
of the unacceptable risk and evaluated several options to control 
chloroprene emissions from (1) process vents, (2) storage vessels, and 
(3) wastewater ``in chloroprene service.'' We also proposed 
requirements to reduce chloroprene emissions from maintenance vents and 
PRDs, as well as a facility-wide chloroprene emissions cap for all 
neoprene production emission sources as a backstop.
    For process vents, we proposed to define ``in chloroprene service'' 
in the P&R I NESHAP at 40 CFR 63.482 to mean each continuous front-end 
process vent and each batch front-end process vent in a process at 
affected sources producing neoprene that, when uncontrolled, contains a 
concentration of greater than or equal to 1 ppmv undiluted chloroprene, 
and when combined, the sum of all these process vents would emit 
uncontrolled, chloroprene emissions greater than or equal to 5 lb/yr 
(2.27 kg/yr).
    For storage vessels of any capacity and vapor pressure in a process 
at affected sources producing neoprene, we proposed to define ``in 
chloroprene service'' in the P&R I NESHAP at 40 CFR 63.482 to mean that 
the concentration of chloroprene of the stored liquid is at least 0.1 
percent by weight. Additionally, we proposed that unless specified by 
the Administrator, owners and operators may calculate the concentration 
of chloroprene of the fluid stored in a storage vessel if information 
specific to the fluid stored is available such as concentration data 
from safety data sheets. We also proposed that the exemption for 
``vessels and equipment storing and/or handling material that contains 
no organic HAP, or organic HAP as impurities only'' listed in the 
definition of ``storage vessel'' at 40 CFR 63.482 does not apply for 
storage vessels in chloroprene service.
    For wastewater, we proposed to define ``in chloroprene service'' in 
the P&R I NESHAP at 40 CFR 63.482 to mean each wastewater stream that 
contains total annual average concentration of chloroprene greater than 
or equal to 10.0 ppmw at any flow rate.
    To reduce risks from process vents in chloroprene service, we 
proposed requirements at 40 CFR 63.485(y)(1) and 40 CFR 63.487(j)(1) to 
reduce emissions of chloroprene by either venting emissions through a 
closed-vent system to a non-flare control device that reduces 
chloroprene by greater than or equal to 99.9 percent by weight or to a 
concentration less than 1 ppmv for each process vent, or to less than 5 
lb/yr for all combined process vents.
    To reduce risks from storage vessels in chloroprene service, we 
proposed a requirement at 40 CFR 63.484(u)(1) to reduce emissions of 
chloroprene by either venting emissions through a closed-vent system to 
a non-flare control device that reduces chloroprene by greater than or 
equal to 99.9 percent by weight or to a concentration less than 1 ppmv 
for each storage vessel.
    To reduce risks from wastewater in chloroprene service, we proposed 
at 40 CFR 63.501(a)(10)(iv) that owners and operators of P&R I sources 
producing neoprene manage and treat any wastewater streams that are 
``in chloroprene service.'' We also proposed at 40 CFR 63.502(n)(8) to 
prohibit owners and operators from injecting water into or disposing of 
water through any heat exchange system in an EPPU if the water contains 
any amount of chloroprene, has been in contact with any process stream 
containing chloroprene, or the water is considered wastewater as 
defined in 40 CFR 63.482.
    In addition, we proposed at 40 CFR 63.165(e)(3)(v)(D) that any 
release event from a PRD in chloroprene service is a violation of the 
standard to ensure that these process vent emissions are controlled and 
do not bypass controls. Also, in order to help reduce chloroprene risk 
from the Neoprene Production source category to an acceptable level, we 
proposed: (1) A requirement at 40 CFR 63.485(z) and 40 CFR 63.487(i)(4) 
that owners and operators cannot release more than 1.0 ton of 
chloroprene from all maintenance vents combined in any consecutive 12-
month period; and (2) a facility-wide chloroprene emissions cap at 40 
CFR 63.483(a)(10) that owners and operators cannot release more than 
3.8 tpy in any consecutive 12-month period from all neoprene production 
emission sources, combined.
    After implementation of the proposed controls for: (1) Process 
vents, (2) storage vessels, and (3) wastewater ``in chloroprene 
service,'' as well as implementation of the proposed requirements to 
reduce chloroprene emissions from maintenance vents, PRDs, and all 
neoprene production emission sources, combined, we proposed that the 
resulting risks would be acceptable from HAP emissions from the 
Neoprene Production source category. We determined at proposal that 
estimated post-control risks would be reduced to 100-in-1 million (down 
from 500-in-1 million) with no individuals exposed to risk levels 
greater than 100-in-1 million (see section III.B.2 of the proposal 
preamble, 88 FR 25080, April 25, 2023) from neoprene production 
emission sources.
    We then considered whether the existing MACT standards provide an 
ample margin of safety to protect public health and whether, taking 
into consideration costs, energy, safety, and other relevant factors, 
additional standards are required to prevent an adverse environmental 
effect. We noted that the EPA previously made a determination that the 
standards for the Neoprene Production source category provided an ample 
margin of safety to protect public health, and that the most 
significant change since that determination was the new 2010 IRIS 
inhalation URE for chloroprene. As such, we focused our ample margin of 
safety analysis on cancer risk for chloroprene since this pollutant, 
even after application of controls needed to get risks to an acceptable 
level, drives cancer risk and cancer incidence (i.e., 99.995 percent of 
remaining cancer incidence is from chloroprene) for the Neoprene 
Production source category. To determine whether the rule provides an 
ample margin of safety, we considered the chloroprene specific 
requirements that we proposed to achieve acceptable risks, as well as 
additional control requirements for chloroprene. The ample margin of 
safety analysis found that additional chloroprene controls would not be 
cost-effective, and therefore, we proposed that the requirements that 
we proposed to achieve acceptable risk would also provide an ample 
margin of safety to protect public health (section III.B.4 of the 
proposal preamble, 88 FR 25080, April 25, 2023). See the technical 
documents titled Residual Risk Assessment for the Polymers & Resins I 
Neoprene Production Source Category in Support of the 2023 Risk and 
Technology Review Proposed Rule; Analysis of Control Options for 
Process Vents and Storage Vessels to Reduce Residual Risk of 
Chloroprene Emissions at P&R I Affected Sources Producing Neoprene; and 
Analysis of Control Options for Wastewater Streams to Reduce Residual 
Risk of Chloroprene From Neoprene Production Processes Subject to P&R I 
(see Docket Item No. EPA-HQ-OAR-2022-0730-0095, -0083 and -0092, 
respectively).

[[Page 42960]]

2. How did the risk review change for the SOCMI and Neoprene Production 
source categories?
    In response to comments received on the proposed rulemaking, we 
revised the risk assessments for the SOCMI and Neoprene Production 
source categories. The comments included our approach to modeling 
flares, which impacted the SOCMI baseline and post control risk 
assessments, and the performance standard for process vents and storage 
vessels in chloroprene service, which impacted the Neoprene Production 
post control risk assessment. The following sections provide the 
results of the revised risk assessments.
a. SOCMI Source Category
    In response to a comment in section 1.1 of the document titled 
Summary of Public Comments and Responses for New Source Performance 
Standards for the Synthetic Organic Chemical Manufacturing Industry and 
National Emission Standards for Hazardous Air Pollutants for the 
Synthetic Organic Chemical Manufacturing Industry and Group I & II 
Polymers and Resins Industry, which is available in the docket for this 
rulemaking, we modified our approach to modeling flares for the SOCMI 
source category and performed a revised risk assessment of baseline 
risk (i.e., risk prior to the implementation of the control 
requirements described in this final action). Based on this revised 
risk assessment, the baseline MIR risk posed by the source category is 
2,000-in-1 million driven by EtO emissions from PRDs (74 percent) and 
equipment leaks (20 percent). The total estimated cancer incidence due 
to emissions from this source category is estimated to be 2 excess 
cancer cases per year. Within 50 km (~31 miles) of HON-subject 
facilities, the population exposed to cancer risk greater than 100-in-1 
million for HON actual and allowable emissions is approximately 83,000 
people, and the population exposed to cancer risk greater than or equal 
to 1-in-1 million is approximately 7.17 million people. Of the 195 
facilities that were assessed for risk, 8 facilities have an estimated 
maximum cancer risk greater than 100-in-1 million. In addition, the 
maximum modeled chronic noncancer TOSHI for the source category based 
on actual and allowable emissions is estimated to be 2 (for respiratory 
effects) at two different facilities (from maleic anhydride emissions 
at one facility and chlorine emissions at another facility). 
Approximately 83 people are estimated to be exposed to a TOSHI greater 
than 1. We note that the only change in these results from the proposal 
is the number of people exposed to cancer risk greater than 100-in-1 
million for HON emissions, which decreased from 87,000 people at 
proposal to 83,000 people here. See Table 3 of this preamble for a 
summary of the HON baseline inhalation risk assessment results.
[GRAPHIC] [TIFF OMITTED] TR16MY24.006

    We conducted a revised assessment of facility-wide (or ``whole-
facility'') risk to characterize the source category risk in the 
context of whole-facility risk. The maximum lifetime individual cancer 
risk posed based on whole-facility emissions is 2,000-in-1 million with 
EtO emissions from PRDs (74 percent) and equipment leaks (20 percent) 
from SOCMI source category emissions driving the risk. The total 
estimated cancer incidence based on facility-wide emission levels is 2 
excess cancer cases per year. Within 50 km (~31 miles) of HON-subject 
facilities, the population exposed to cancer risk greater than 100-in-1 
million for HON facility-wide emissions is approximately 90,000

[[Page 42961]]

people, and the population exposed to cancer risk greater than or equal 
to 1-in-1 million is approximately 8.92 million people. The maximum 
chronic noncancer TOSHI posed by whole-facility emissions is estimated 
to be 4 (for respiratory effects) due mostly (98 percent) to emissions 
from 2 facilities. Emissions from one facility contribute to 83 percent 
of the TOSHI, with approximately 60 percent of the total TOSHI from 
non-source category emissions of chlorine and another 15 percent from 
source category emissions of chlorine. Emissions from the second 
facility contribute to 15 percent of the TOSHI, with approximately 11 
percent of the total TOSHI from source category emissions of acrylic 
acid and 2 percent from source category emissions of acrylonitrile. 
Approximately 1,100 people are estimated to be exposed to a TOSHI 
greater than 1 due to whole-facility emissions. Again, we note that the 
only change in these results from the proposal is the number of people 
exposed to cancer risk greater than 100-in-1 million, which decreased 
from 95,000 people at proposal to 90,000 people here (due to our 
modified approach to modeling flares, discussed above).
    Finally, we conducted a revised assessment to evaluate risks after 
implementation of the control requirements described in this action. 
After implementation of the controls, the MIR for the SOCMI source 
category is reduced to 100-in-1 million (down from 2,000-in-1 million) 
with no individuals exposed to risk levels greater than 100-in-1 
million from HAP emissions from the SOCMI source category, which is the 
same as in the proposal. The total population exposed to risk levels 
from the SOCMI source category greater than or equal to 1-in-1 million 
living within 50 km (~31 miles) of a facility would be reduced from 
7.17 million people to 6.27 million people. The cancer incidence would 
be reduced from 2 excess cancer cases per year to 0.4 excess cancer 
cases per year. The maximum modeled chronic noncancer TOSHI for the 
source category remains unchanged. Specifically, the chronic noncancer 
TOSHI is estimated to be 2 (for respiratory effects) at two different 
facilities (from maleic anhydride emissions at one facility and 
chlorine emissions at another facility) with approximately 83 people 
estimated to be exposed to a TOSHI greater than 1. The estimated worst-
case off-site acute exposures to emissions from the SOCMI source 
category also remains unchanged, with a maximum modeled acute HQ of 3 
based on the RELs for chlorine and acrolein. The only change in these 
results from proposal is the number of people exposed to cancer risk 
levels greater than or equal to 1-in-1 million (6.27 million here 
compared to 5.7 million at proposal) due to us not finalizing (in 
response to persuasive comments received during the public comment 
period) the requirement at 40 CFR 63.108(p) that would prohibit owners 
and operators from sending more than 20 tons of EtO to all of their 
flares combined in any consecutive 12-month period (for more 
information on this, see Section IV.A.3.d.v of this preamble). Table 4 
of this preamble summarizes the reduction in risks due to emissions 
from the SOCMI source category based on the controls in this action. 
For further details on the revised risk assessment for the SOCMI source 
category, see the document titled Residual Risk Assessment for the 
SOCMI Source Category in Support of the 2024 Risk and Technology Review 
Final Rule, which is available in the docket for this rulemaking.
    Table 4 of this preamble also summarizes the facility-wide risks 
for facilities in the SOCMI source category. The post-control facility-
wide MIR remains 2,000-in-1 million, driven by EtO emissions from 
Polyether Polyols Production source category emissions sources, which 
the EPA intends to address in a future action. Further, we note that 
the fenceline monitoring action level of 0.2 [mu]g/m\3\ for EtO will 
reduce EtO emissions and therefore risks below these levels, with the 
MIR reduced to 1,000-in-1 million or lower and the number of 
individuals exposed to cancer risk levels greater than 100-in-1 million 
and greater than or equal to 1-in-1 million expected to be lower than 
those in Table 4 of this preamble.

[[Page 42962]]

[GRAPHIC] [TIFF OMITTED] TR16MY24.007

b. Neoprene Source Category
    In response to a comment in section IV.A.3.e.i of this preamble, we 
revised the performance standard for process vents and storage vessels 
in chloroprene service for the Neoprene Production source category. 
This revision did not change the baseline source category or facility-
wide risk assessments for the Neoprene Production source category from 
proposal (see section IV.A.1.b of this preamble and Table 5 of this 
preamble). The revised assessment indicated that, after implementation 
of the controls, the MIR for the Neoprene Production source category is 
100-in-1 million (down from 500-in-1 million in the pre-control 
baseline) with no individuals exposed to risk levels greater than 100-
in-1 million from HAP emissions from the Neoprene Production source 
category. This result is the same as in the proposal. The total 
population exposed to risk levels from the Neoprene Production source 
category greater than or equal to 1-in-1 million would be reduced from 
690,000 people to 58,000 people. The total estimated cancer incidence 
of 0.05 drops to 0.01 excess cancer cases per year. For the risk 
results estimated after implementation of controls, the two changes 
from proposal are the number of people exposed to risk levels greater 
than or equal to 1-in-1 million (58,000 here compared to 48,000 at 
proposal) and the cancer incidence (0.01 here compared to 0.008 at 
proposal) from HAP emissions from the Neoprene Production source 
category. All other results remained the same. Table 5 of this preamble 
summarizes the reduction in cancer risks due to emissions from the 
Neoprene Production source category based on the controls in this 
action. For further details on the revised risk assessment for the 
Neoprene Production source category, see the document titled Residual 
Risk Assessment for the Polymers & Resins I Neoprene Production Source 
Category in Support of the 2024 Risk and Technology Review Final Rule, 
which is available in the docket for this rulemaking.
    Table 5 of this preamble also provides the facility-wide risks for 
the facility in the Neoprene Production source category, which are of 
increased importance due to the secondary

[[Page 42963]]

fenceline action level for chloroprene, before (pre-control baseline) 
and after controls (post-control) of neoprene production emission 
sources in this action. The post-control facility-wide MIR is 200-in-1 
million, driven by chloroprene emissions from SOCMI and neoprene 
production emission sources. The secondary fenceline action level of 
0.3 [mu]g/m\3\ for chloroprene will further reduce chloroprene 
emissions and therefore risks below these levels, with the MIR expected 
to be 100-in-1 million or lower, with no individuals exposed to 
lifetime cancer risk levels greater than 100-in-1 million, and the 
number of people exposed to cancer risk levels greater than or equal to 
1-in-1 million expected to be lower than those in Table 5 of this 
preamble.
[GRAPHIC] [TIFF OMITTED] TR16MY24.008

3. What key comments did we receive on the risk review, and what are 
our responses?
    This section provides summaries of and responses to the key 
comments received regarding our risk assessment for the SOCMI source 
category, our risk assessment for the Neoprene Production source 
category, the proposed requirements to reduce EtO emissions from the 
SOCMI source category, and the proposed requirements to reduce 
chloroprene emissions from the Neoprene Production source category. We 
received comments in support of and against the proposed residual risk 
review, the IRIS URE used in the review, and our determination that 
additional controls were warranted under CAA section 112(f)(2) for the 
SOCMI and Neoprene Production source categories. Other comments on 
these issues, as well as the EtO IRIS URE, chloroprene IRIS URE, and on 
additional issues regarding the residual risk review and the EPA's 
proposed changes based on the residual risk review, can be found in the 
document titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking.
a. EtO IRIS URE
    We received numerous comments in support of, and in opposition to, 
the EPA's use of the EtO IRIS value in assessing cancer risk for a 
source category under CAA section 112(f)(2) for EtO. After careful 
review of the comments, the Agency has determined that commenters did 
not identify new scientific information that would alter aspects of the 
EPA IRIS assessments or call into question the scientific judgments 
reflected in those assessments. The EPA continues to affirm its 
determination that the IRIS assessments are scientifically sound and 
robust and represent the best available inhalation cancer risk values 
for EtO.\34\ These comments are not summarized in this preamble. 
Instead, all of these comments (related to the EPA's use of the EtO 
IRIS value for CAA section 112(f)(2) risk assessment) and the EPA's 
responses are in the document titled Summary of Public Comments and 
Responses for New Source Performance Standards for the Synthetic 
Organic Chemical Manufacturing Industry and National Emission Standards 
for Hazardous Air Pollutants for the Synthetic Organic Chemical 
Manufacturing Industry and Group I & II Polymers and Resins Industry, 
which is available in the docket for this rulemaking.
---------------------------------------------------------------------------

    \34\ 87 FR 77985 (Dec. 21, 2022), Reconsideration of the 2020 
National Emission Standards for Hazardous Air Pollutants: 
Miscellaneous Organic Chemical Manufacturing Residual Risk and 
Technology Review, Final action; reconsideration of the final rule.

---------------------------------------------------------------------------

[[Page 42964]]

b. Chloroprene IRIS URE
    We received numerous comments in support of, and in opposition to, 
the EPA's use of the chloroprene IRIS value in assessing cancer risk 
for a source category under CAA section 112(f)(2) for chloroprene. 
After careful review of the comments, the Agency has determined that 
commenters did not identify new scientific information that would alter 
aspects of the EPA IRIS assessments or call into question the 
scientific judgments reflected in those assessments. The EPA continues 
to affirm its determination that the IRIS assessments are 
scientifically sound and robust and represent the best available 
inhalation cancer risk values for chloroprene.\35\ These comments are 
not summarized in this preamble. Instead, all of these comments 
(related to the EPA's use of the chloroprene IRIS value for CAA section 
112(f)(2) risk assessment) and the EPA's responses are in the document 
titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking.
---------------------------------------------------------------------------

    \35\ U.S. EPA. March 14, 2022. Response to the Request for 
Correction of the 2010 IRIS Chloroprene Toxicological Review. 
www.epa.gov/system/files/documents/2022-03/ord-22-000-2789-final-rfc-21005-response-03-01-2022-new.pdf
---------------------------------------------------------------------------

c. Risk Assessment
    Several commenters provided comments on specific facilities in the 
EPA risk assessment and submitted additional data for the EPA to use 
for assessing public health risks. We also received comments regarding 
environmental justice, our community-based risk assessment, and the 
statutory authority to assess risk. Key comments on these topics are as 
follows:
i. Emissions Data
    Comment: Commenters objected to the use of the 2017 National 
Emissions Inventory (NEI) data without corrections or revisions to 
model risk. These commenters requested that the EPA incorporate all of 
the revisions that were provided by various companies that participated 
in the EPA's January 18, 2022, CAA section 114 request. A commenter 
explained that the EPA allowed facilities to update emissions values so 
the EPA's assessment was representative of current operations and 
improvements to both emissions controls and emissions estimation 
methodologies. The commenter pointed out that although several 
facilities provided revisions to the EPA for their NEI modeling file 
inputs, the EPA rejected many of them. The commenter contended that if 
the EPA corrected its emissions modeling file to reflect more accurate 
emissions levels or upgraded emissions controls, it would determine, 
for a number of facilities, that risks were acceptable, or some 
emissions units were not meaningfully contributing to risk.
    Commenters provided the following specific examples of corrections 
facilities made to their 2017 NEI data, but were rejected by the EPA:
     Huntsman Petrochemical--Conroe Plant (ID 4945611); Conroe, 
TX
    Used actual emissions for equipment leaks.
    Used updated emission rates for holding ponds.
    Used actual operation hours for pumps.
     Eastman Chemical Company--Texas Operations (ID 4941511); 
Longview, TX
    Provided consistency with process vent stack test data.
    Used refined El Paso Method response factors for cooling towers.
    Used updated wastewater emissions calculations.
    Used updated fugitive emissions calculations.
     Sasol Chemicals--Lake Charles Chemical Complex (ID 
8468011); Westlake, LA
    Removed a process vent not subject to HON.
    Removed a transfer rack not subject to HON.
     BASF Corporation--Geismar Site (ID 8465611); Geismar, LA
    Used more recent process vent stack test data.
     Clear Lake Plant (ID 4057911); Pasadena, TX
    Used revised stream compositions to estimate equipment leak 
emissions.
    Used revised calculation methodologies to estimate process vent 
emissions.
     Shell Chemical--Geismar Plant (ID 7445611); Geismar, LA
    Installed a thermal oxidizer to reduce EtO emissions.
    Used more accurate concentration data and targeted source control 
efforts for wastewater.
    Used more frequent connector monitoring to estimate equipment leak 
emissions.
    Changed the specification of residual EtO in Ethoxylate product to 
reduce EtO emissions.
    Installed a thermal oxidizer on some process vents.
    By incorporating the above revisions, commenters insisted the 
residual risk attributable to EtO would be reduced and the EPA would 
conclude that risks are acceptable, even if the current IRIS value for 
EtO is used.
    A different commenter asserted that the EPA cannot rely on a single 
year of emissions data from HON and P&R I sources to evaluate residual 
risk. The commenter explained that the NEI does not provide a reliable 
basis for estimating downwind concentrations of specific HAPs and the 
resulting cancer or noncancer risk to the communities nearby. The 
commenter said that, by the EPA's conclusions, fenceline monitoring 
data has shown that modeled concentrations greatly underestimate 
monitored concentrations. The commenter contended that the reliance on 
2017 NEI data would contradict the EPA's own statements and would not 
provide the ample margin of safety that the CAA requires. While the NEI 
can be used as a starting point, the commenter recommended that the EPA 
should select the highest annual emissions that each source has 
reported to either the Toxics Release Inventory (TRI) or the NEI within 
the most recent five-year period for which data are available. The 
commenter explained that TRI reports are filed annually and may provide 
a more accurate picture of current emissions, and it would be 
irrational to base a residual risk assessment for sources on the 2017 
NEI when the same sources are reporting higher emissions in the 2017-
2021 TRI or 2020 NEI reports.
    Similarly, a commenter objected to the EPA's use of the 2019 
baseline actual emissions for Denka Performance Elastomers, LLC to 
assess residual risk of chloroprene emissions. The commenter said that 
the 2019 baseline actual emissions are substantially lower than 
historic actual emission levels reported to the Louisiana Department of 
Environmental Quality (LDEQ) from 1991 through 2017; and the EPA's risk 
report does not appear to include a description of the primary causes 
for the observed 2019 emission reductions. The commenter added that the 
combined average 2019 community monitored chloroprene concentration is 
2.5 times the EPA's 2019 modeled average fenceline concentration (0.74 
[mu]g/m\3\). The commenter also asserted that the 2019 actual annual 
baseline emissions do not reflect sustainable chloroprene emission 
reductions achieved through work practice standards or application of 
MACT emission controls given that the average chloroprene concentration 
measured at 5th Ward Elementary during the first 6 months of 2020 were

[[Page 42965]]

~52 percent higher than the measured 2019 concentrations.
    Response: We disagree with commenters who object to the use of the 
2017 NEI data. We relied on the January 2021 version of the 2017 NEI 
dataset because it provided the best available data for EtO emissions 
and other HAP emissions for the SOCMI source category and the Neoprene 
Production source category covered under the P&R I NESHAP. However, in 
a few instances where facility-specific data were not available or not 
reflective of current controls in the 2017 NEI, we attempted to obtain 
data from a more recent dataset (e.g., review of emissions inventory 
data from our CAA section 114 request, more recent inventories 
submitted to states, or the 2018 NEI). Where we did not have better 
data, we did not update our dataset. Of note, for the one neoprene 
production facility (which is also part of the SOCMI source category), 
we used the 2019 emissions inventory that was provided to the EPA from 
our CAA section 114 request. The NEI data were also used to develop the 
other parameters needed to perform the risk modeling analysis, 
including the emissions release characteristics, such as stack heights, 
stack diameters, flow rates, temperatures, and emission release point 
locations.
    We note that the EPA has an obligation to use the best available 
data for establishment of risk-based standards and generally updates 
the dataset where we have sufficient rationale or improved data (e.g., 
relevant stack test data, documented process concentrations), but the 
EPA has discretion to reject updated emissions estimates when 
insufficient rationale and information is provided. In general, we 
rejected the corrections facilities made to their 2017 NEI data (i.e., 
the corrections listed by commenters as specified in this comment 
summary) due to insufficient information when numbers were updated 
without a clear or substantive explanation of why emissions changed and 
where EPA could not fully verify the changes. For example, many 
suggested changes were due to revisions in the engineering calculation 
methods with no documented detailed calculations shown. Other examples 
include changing calculation input assumptions for the amount of HAP in 
process streams where no source testing/sampling was provided by 
commenters to support their suggested changes. Further, in many cases 
we also rejected corrections listed by commenters related to pollutants 
that drive cancer risks for HON (i.e., EtO) and neoprene production 
sources (i.e., chloroprene) given that we contend, based on the 
fenceline data, that the modeling file emissions for these pollutants 
are underestimated.
    Regarding the commenter's objection to the EPA's use of the 2019 
baseline actual emissions for Denka Performance Elastomers, LLC to 
assess residual risk of chloroprene emissions, the facility's emissions 
inventory was provided to the EPA pursuant to our CAA section 114 
request. In particular, the EPA requested emission inventories from the 
past 5 years (i.e., 2016-2020) from the facility's operations as part 
of this request. As 2017 NEI data did not represent current controls 
being employed at Denka Performance Elastomers, LLC, the EPA chose to 
use the most current data it had available, which is reflective of 
current operations and emissions. Given the EPA's concerns about 
decreased production and emissions in 2020 from the COVID-19 pandemic, 
we elected to use Denka Performance Elastomer, LLC's 2019 emissions 
inventory submitted as part of the CAA section 114 request in its risk 
assessment for the HON and Neoprene Production source categories in 
lieu of the 2017 NEI data. The EPA also reviewed chloroprene emission 
records to determine whether the emissions were associated with HON 
processes, neoprene processes, or other non-HON and non-neoprene 
processes and updated the regulatory code in the risk modeling input 
files to account for this review.
    In summary, we took many steps to develop an emissions modeling 
file that was representative of emissions from HON and P&R I sources, 
including declining to revise data where we had insufficient rationale 
or information to verify commenters' suggested changes. As described in 
more detail in the preamble to the proposed rulemaking (88 FR 25080, 
April 25, 2023), the EPA used many sources of information to develop 
the HAP emissions inventory used to assess risks for this rulemaking, 
including, but not limited to, the 2017 NEI and information gathered 
under our CAA section 114 authority. The EPA typically has wide 
latitude in determining the extent of data-gathering necessary to solve 
a problem and courts generally defer to the agency's decision to 
proceed on the basis of imperfect scientific information, rather than 
to ``invest the resources to conduct the perfect study.'' Sierra Club 
v. EPA, 167 F. 3d 658, 662 (D.C. Cir. 1999) (``If the EPA were required 
to gather exhaustive data about a problem for which gathering such data 
is not yet feasible, the agency would be unable to act even if such 
inaction had potentially significant consequences . . . . [A]n agency 
must make a judgment in the face of a known risk of unknown degree.'' 
Mexichem Specialty Resins, Inc., 787 F.3d. 561 (D.C. Cir. 2015)).
    For further details on the assumptions and methodologies used to 
estimate actual emissions, see Appendix 1 of the documents titled 
Residual Risk Assessment for the SOCMI Source Category in Support of 
the 2024 Risk and Technology Review Final Rule and Residual Risk 
Assessment for the Polymers & Resins I Neoprene Production Source 
Category in Support of the 2024 Risk and Technology Review Final Rule, 
which are both available in the docket for this rulemaking.
    Comment: A commenter contended that the EPA's inclusion of 
infrequent, episodic events in their risk assessment is inappropriate. 
The commenter explained that short-term or one-time emissions release 
events are not representative of concentrations an individual would be 
exposed to over a lifetime. Furthermore, the commenter contended that 
the EPA should also have excluded EtO emissions related to SSM events 
from its voluntary risk analysis because the EPA is statutorily 
obligated to address SSM events under CAA sections 112(d)(2) and 
(d)(3).
    Response: If any operating period (including SSM periods) leads to 
noncompliance with standards, we would not model such noncompliance for 
purposes of assessing risk in the CAA section 112(f) risk review 
because the agency estimates risk based on compliance with the 
established NESHAP. The statute does not require the agency to 
determine risk based on some assumed level of noncompliance. In 
addition, the appropriate remedy for noncompliance with a NESHAP is an 
enforcement action seeking to require the source to come into 
compliance with the standard.
    Emissions events in violation of the standards, whether or not they 
are caused by malfunction events, are not considered as part of risk 
analyses. The EPA interprets CAA section 112 as not requiring emissions 
that occur during periods of malfunction to be factored into 
development of CAA section 112 standards, and this reading has been 
upheld as reasonable by the U.S. Court of Appeals for the District of 
Columbia in U.S. Sugar Corporation v. EPA, 830 F.3d 579, 606-10 (D.C. 
Cir. 2016). Consistent with previous risk assessments, the EPA 
considered both allowable and actual emissions in assessing chronic 
inhalation exposure and risk under CAA section 112(f)(2) for the SOCMI 
source category and the Neoprene Production source category covered 
under the P&R I NESHAP (see,

[[Page 42966]]

e.g., the National Emission Standards for Coke Oven Batteries [70 FR 
19998-19999, April 15, 2005] and the proposed and final HON (71 FR 
34428, June 14, 2006 and 71 FR 76603, December 21, 2006, 
respectively)). The final rule is designed to require sources to comply 
during all periods of operation. As explained in the preamble to the 
proposed rule (see 88 FR 25080, April 25, 2023), it is not generally 
possible to model malfunctions in the risk assessment, because by 
nature they are infrequent and unpredictable, and we generally have 
insufficient information to model these types of events. The main 
purpose of the risk review for these source categories is to evaluate 
whether the emission limits--the ``standards promulgated pursuant to 
subsection (d),'' not the non-compliance with those standards--should 
be made more stringent to reduce the risk posed after compliance with 
the underlying MACT standards. To the extent that a source is violating 
an underlying MACT standard, it is unlikely that tightening of the 
emission standard as a result of the residual risk review will avoid or 
mitigate such violations. In other words, a source that is violating a 
MACT emissions standard promulgated under CAA section 112(d) would not 
be any more likely to be able to avoid such violations and comply with 
a different presumably more stringent standard promulgated under CAA 
section 112(f). Such events are violations and subject to enforcement 
by the EPA, the states, or citizens, and an action for injunctive 
relief is the most effective means to address violations, whether or 
not they are caused by malfunctions, if an emissions event poses a 
significant health or environmental risk.
    The EPA notes that the final Petroleum Refinery Sector Rule 
included a conservative, screening-level assessment (not a refined risk 
assessment) performed using available information collection response 
(ICR) data to see the impacts of certain non-routine emissions events 
from PRDs and flares. [80 FR 75178, December 1, 2015] That assessment 
conservatively combined routine and non-routine emissions merely to 
define an upper bound of combined risk, and the EPA ultimately 
concluded that risks were not significantly different, given the 
uncertainties and conservative nature of the screening. In this risk 
assessment, the EPA did have information on EtO emissions from PRD 
events at one facility as they were reported to the Texas Commission on 
Environmental Quality (TCEQ). The modeling indicated that emissions 
from one single PRD release contributed to the majority of the cancer 
risk for that facility and as such we proposed and are finalizing 
requirements that any releases from PRD in EtO service are violations 
of these emission standards. The EPA did not include other additional 
emission estimates from non-routine PRD or flare events in the 
emissions inventory that was used to assess residual risk. Other than 
for highly toxic compounds such as EtO and chloroprene, we have found 
that non-routine emissions from PRDs and flares in similar source 
categories, including ethylene production facilities and petroleum 
refineries, have not significantly affected risks (see, e.g., 85 FR 
75187-75188, December 1, 2015).
ii. Environmental Justice
    Comment: Commenters asserted that the EPA should continue to place 
environmental justice at the forefront as it moves through the 
regulatory process and ensure it takes steps to reduce impacts on 
overburdened communities. A commenter pointed out that populations with 
lung disease, children, people with heart disease, and others are 
typically at higher risk of health harm from air pollution. The 
commenter declared that the EPA must place a priority on ensuring the 
current administration meets its goals on improving environmental 
justice, ensuring that people who live near these facilities do not 
continue to face overlapping health inequities that increase their 
overall risk. Other commenters called attention to the 7 million people 
who live near chemical plants who face serious cancer risk from 
uncontrolled toxic air emissions and are majority Black and Brown 
residents. Commenters stated that chemical manufacturing facilities are 
commonly located in communities of color and low-income neighborhoods 
(especially in Texas and Louisiana) and the emissions reductions from 
the proposed standards will help reduce the burden on 
disproportionately impacted communities.
    Another commenter asserted that the EPA should strengthen the 
proposed HON standards to further reduce HAP emissions with the goal of 
eliminating racial disparities in exposure at all risk levels. The 
commenter claimed that, even after adoption of the proposed rule, about 
1.6 million people of color will still face serious cancer risk at the 
1-in-1 million level simply by living within 10 km (6.2 miles) of toxic 
air emissions emitted by regulated sources from chemical manufacturing 
plants. The commenter contended that the EPA succeeded at identifying 
environmental justice concerns, however it failed to address these 
concerns. The commenter cited the EPA's environmental justice web page, 
specifically the phrase ``no group of people should bear a 
disproportionate share of the negative environmental consequences,'' 
and stated that people of color will still bear a disproportionate 
share of exposure to HAPs and resulting cancer risk if the HON rule is 
adopted as proposed. Furthermore, the commenter contended that the EPA 
failed to cite and analyze the scientific evidence that shows that 
people of color are also uniquely susceptible to the health effects of 
toxic air pollutants, in addition to being more highly exposed, due to 
the cumulative impacts from a combination with other psycho-social 
stressors including racism, poverty, lack of access to health care and 
healthful foods.
    Response: The EPA is directed, to the greatest extent practicable 
and permitted by law, to make environmental justice part of its mission 
by identifying and addressing, as appropriate, disproportionate and 
adverse human health or environmental effects of its programs, 
policies, and activities on communities with environmental justice 
concerns. The EPA's environmental justice policies promote justice, 
including access to health impact data, by providing information on the 
types of environmental justice harms and risks that are prevalent in 
communities with environmental justice concerns. No such policies 
mandate consideration of any specific factors or particular outcomes 
from an action, but they direct that environmental justice analysis be 
performed as part of regulatory impact analysis, as appropriate, so 
that the public can have this information. As noted above, the 
assessment of costs and benefits described herein and in the RIA, 
including the environmental justice analysis, is presented for the 
purpose of providing the public with as full as possible an 
understanding of the potential impacts of this final action. The EPA 
notes that analysis of such impacts is distinct from the determinations 
finalized in this action under CAA sections 111 and 112, which are 
based solely on the statutory factors the EPA is required to consider 
under those sections.
    The EPA evaluated the risks for various populations as described in 
the demographic analysis in the proposed rule preamble and in the 
documents titled Analysis of Demographic Factors for Populations Living 
Near Hazardous Organic NESHAP (HON) Operations--Final; Analysis of 
Demographic Factors for Populations Living Near Hazardous Organic 
NESHAP (HON) Operations:

[[Page 42967]]

Whole Facility Analysis--Final; Analysis of Demographic Factors for 
Populations Living Near Neoprene Production Operations--Final; Analysis 
of Demographic Factors for Populations Living Near Neoprene Production 
Operations: Whole Facility Analysis--Final; and Analysis of Demographic 
Factors for Populations Living Near Polymers and Resins I and Polymer 
and Resins II Facilities, which are available in the docket for this 
rulemaking. The EPA used its Environmental Justice Risk and Proximity 
Analysis Tool (``EJ Tool'') to link HEM/AERMOD modeling results for the 
HON and P&R sources with detailed census data, in order to evaluate the 
distribution of cancer and noncancer risks for different demographic 
factors (including racial, ethnic, age, economic, educational, and 
linguistically isolated population categories). In addition to 
evaluating risk distribution, this analysis also presents the 
demographic composition of the population located within close 
proximity (10 km) and within the overall HEM/AERMOD model domain (50 
km) of the source category emissions (irrespective of risk). The 
following demographic groups were included in this risk and proximity 
analysis:
    Total population;
    White;
    Black (or African American);
    American Indian or Alaska Native;
    Other races and multiracial;
    Hispanic or Latino;
    Children 17 years of age and under;
    Adults 18 to 64 years of age;
    Adults 65 years of age and over;
    Adults without a high school diploma;
    People living below the poverty level, and
    Linguistically isolated people.
    The total population statistics near facilities in the source 
category, irrespective of risk (i.e., at all risk levels) are in the 
Analysis of Demographic memorandum. These results indicate that the 
demographic composition of the population located within close 
proximity (10 km) and within the overall HEM/AERMOD model domain (50 
km) of the source category emissions are the same or lower than the 
nationwide average for all communities of environmental justice 
concern.
    Considering risk, the post-control scenario is expected to reduce 
cancer incidence across all demographic groups including communities of 
environmental justice concern. Regarding the commenter's concern about 
the post-control risk exposure of people of color, the requirements for 
the HON/SOCMI facilities reduce the chronic cancer risks for Black 
individuals as follows: >100-in-1 million from 12,000 people to zero 
people; >=50-in-1 million from 59,000 to 4,000; and >=1-in-1 million 
from 694,000 to 692,000. The rule has the greatest impact at the higher 
chronic cancer risk levels. Additionally, regarding concern about the 
unique susceptibility of people of color to the health impacts of toxic 
air pollutants, the EPA is currently exploring data and methods to make 
it possible to more explicitly evaluate the role of non-chemical 
stressors in an environmental justice analysis.
iii. Community-Based Risk Assessment
    Comment: Commenters said that they supported the addition of the 
EPA's community-based risk assessment in the rulemaking proposal given 
that it reflects a commitment to evidence-based decision-making and the 
well-being of communities affected by these facilities, and implored 
the EPA to continue to employ rigorous community risk assessments in 
future rulemakings. A commenter remarked that in addition to the 
communities' benefit, workers within chemical plants would benefit as 
well.
    Some commenters supported the EPA expanding the community-based 
risk assessment to include air toxics-related cancer risks from all 
large facilities in communities in the vicinity, including sources that 
would not be covered by the rule. The commenters explained that since 
the public's exposure is not limited to one chemical or source category 
at a time, this is a step in the right direction. The commenters 
suggested these expanded community-based risk assessments be standard 
practice. Other commenters proposed to expand the community-based risk 
assessment to not only include all large facilities in the area, but 
also include other types of sources (e.g., mobile sources), include 
non-cancer endpoints (e.g., miscarriages, birth defects, 
neurodevelopmental impacts), and explore other routes of exposure 
beyond inhalation. Commenters claimed this could be accomplished if the 
EPA went a step further than the community risk assessment and 
performed a cumulative risk assessment. The commenter explained that a 
cumulative risk assessment would take into account chemical and non-
chemical stressors, and how these stressors interact to promote adverse 
health effects.
    Other commenters asserted that the EPA should strengthen the 
proposed HON standards to further reduce HAP emissions with the goal of 
eliminating or reducing the number of people exposed at or above 1-in-1 
million cancer risk to the maximum extent feasible. A commenter claimed 
that, under the proposed rule, about 5.7 million people would still 
face serious cancer risk at the 1-in-1 million level simply by living 
within 50 km (31 miles) of toxic air emissions that are being emitted 
by regulated sources from chemical manufacturing plants. The commenter 
further claimed that, by living within 10 km (6.2 miles), there is only 
a 10 percent reduction of total people at this risk level. The 
commenter contended that the EPA has done more in the past, 
specifically when 99 percent of the population living within 50 km had 
cancer risk reduced to 1-in-1 million through the Benzene NESHAP rule.
    On the contrary, a commenter argued that the EPA's ``whole-
facility'' and ``community-based'' risk assessments are irrelevant to 
the proposed rule because the EPA is limited to considering only risks 
associated with the source category that is the subject of the risk 
assessment. The commenter added these broader risk analyses are less 
reliable due to uncertainties in the data used.
    Response: We appreciate the commenters' support of the community-
based risk assessment. In response to reducing the number of people 
exposed at or above 1-in-1 million cancer risk to the maximum extent 
feasible, the EPA's ample margin-of-safety determinations are conducted 
in accord with the two-step framework set forth in the Benzene NESHAP. 
When making its ample margin of safety determination, the EPA does 
consider health risks and their associated uncertainties, but also 
considers costs, technical feasibility, and other factors. For the 
SOCMI source category, in Step 1 of the Benzene NESHAP framework, the 
risks were determined to be unacceptable given all of the health 
information. Standards were proposed to bring the risk down to 
acceptable levels, not considering costs. Once the risks were 
determined to be at acceptable levels, Step 2 of the Benzene NESHAP 
framework requires the EPA to again consider health risks, but also 
cost, technical feasibility, and other factors, in determining if any 
additional controls should be required to achieve an ample margin of 
safety. For the SOCMI source category, the EPA proposed that it was not 
appropriate to require additional controls (either based on costs, 
feasibility, or availability) beyond what were proposed to achieve 
acceptable risks, regardless of health risks, thus we concluded that 
the proposed standards to address unacceptable risks also achieved an 
ample margin of safety.

[[Page 42968]]

    Comment: Some commenters asserted that the community-based risk 
assessments should be used when making regulatory decisions, although 
there may be implementation challenges due to potential limitations in 
the EPA's statutory authority. A commenter explained that the CAA 
requires the EPA to investigate whether its regulations provide an 
``ample margin of safety'' to protect public health, and if a community 
risk assessment demonstrates that a proposed rule does not provide an 
``ample margin of safety'' (because of other health stressors in the 
community not captured by other risk assessments), then the EPA should 
revise the proposed rule.
    Response: Section 112(f)(2) of the CAA expressly preserves our use 
of the two-step process for developing standards to address residual 
risk and interpret ``acceptable risk'' and ``ample margin of safety'' 
as developed in the Benzene NESHAP (54 FR 38044, September 14, 1989). 
In the Benzene NESHAP, the EPA concluded that ``With respect to 
considering other sources of risk from benzene exposure and determining 
the acceptable risk level for all exposures to benzene, EPA considered 
this inappropriate because only the risk associated with the emissions 
under consideration are relevant to the regulation being established 
and, consequently, the decisions being made.'' (54 FR 38044, September 
14, 1989). Our authority to use the two-step process set forth in the 
Benzene NESHAP, and to consider a variety of measures of risk to public 
health, is discussed more thoroughly in the preamble to the proposed 
rule (see 88 FR 25080, April 25, 2023). Nothing in the CAA or the 
Benzene NESHAP in any way forecloses us from considering facility-wide 
risks in making a determination under CAA section 112(f)(2), as such 
information can constitute relevant health information.
    Although not appropriate for consideration in the determination of 
acceptable risk presented by just source category emissions, we note 
that contributions to risk from sources outside the source category 
under review could be one of the relevant factors considered in the 
ample margin of safety determination, along with cost and economic 
factors, technological feasibility and other factors. For the SOCMI 
source category, the EPA proposed that it was not appropriate to 
require additional controls (either based on costs, feasibility, or 
availability) beyond what were proposed to achieve acceptable risks, 
regardless of health risks, thus we concluded that the proposed 
standards to address unacceptable risk posed by emissions from the 
SOCMI source category also achieved an ample margin of safety.
    The development of community-based estimates provides additional 
information about the potential cumulative risks in the vicinity of the 
RTR sources, as one means of informing potential risk-based decisions 
about the RTR source category in question. We recognize that, because 
these risk estimates were derived from facility-wide emissions 
estimates which have not generally been subjected to the same level of 
engineering review as the source category emission estimates, they may 
be less certain than our risk estimates for the source category in 
question, but they remain important for providing context as long as 
their uncertainty is taken into consideration in the process.
iv. Statutory Authority To Conduct Risk Assessment
    Comment: Commenters argued that the EPA is obligated to consider 
costs as part of their optional second residual risk review. Some 
commenters said that the EPA's refusal to consider costs of the 
controls proposed to reduce EtO emissions is beyond the EPA's statutory 
authority, and is arbitrary and capricious. The commenters said that 
unless specifically instructed otherwise, rational decision making 
requires the consideration of cost. The commenters contended that 
unless a statute precludes consideration of costs, ``[c]onsideration of 
cost reflects the understanding that reasonable regulation ordinarily 
requires paying attention to the advantages and the disadvantages of 
agency decisions.'' Michigan v. EPA, 576 U.S. 743, 754 (2015). Some 
commenters added that the Supreme Court has before held that 
consideration of costs must occur when the EPA finds that it is 
``appropriate and necessary'' to regulate emissions under the CAA. 
Michigan v. EPA., 576 U.S. 743, (2015) (holding costs must be 
considered when determining whether it is ``appropriate and necessary'' 
to regulate stationary sources of fossil-fuel fired power plants under 
CAA section 7412(n)). A commenter opined that because it would be 
``unreasonable to read an instruction to an administrative agency to 
determine whether `regulation is appropriate and necessary' as an 
invitation to ignore costs,'' similarly, it would be unreasonable here 
for the EPA to ignore costs after it discretionally determined that it 
was ``necessary'' to ``revisit and revise'' the residual risk 
threshold.
    The commenters said the residual risk provisions, by reference to 
the Benzene NESHAP, allow the EPA to exclude costs only in initially 
determining acceptable risk, but in setting an ample margin of safety, 
costs are to be considered. The commenters contended that if the EPA 
has authority to conduct subsequent residual risk findings (which the 
commenters dispute), then the entire exercise is a secondary one that 
must take cost into consideration. A commenter explained that under 
most circumstances under CAA section 112, even when as an initial step, 
consideration of cost may be prohibited, the CAA requires consideration 
of cost in subsequent steps and Congress has constrained circumstances 
under which cost cannot be considered; therefore, the EPA is acting 
contrary to Congressional intent by attempting to expand its authority 
to conduct a risk review more than once, which is the only way in which 
the EPA could attempt to revise the NESHAP without considering costs.
    Commenters cited the following court rulings and other references 
to support their view that the EPA is obligated to consider costs as 
part of their optional second residual risk review:
     White Stallion Energy Center, LLC v. E.P.A., 748 F.3d 1222 
(2014) (Kavanaugh concurring in part and dissenting in part) (citing 
and quoting RICHARD L. REVESZ & MICHAEL A. LIVERMORE, RETAKING 
RATIONALITY 12 (2008) (``For certain kinds of governmental programs, 
the use of cost-benefit analysis is a requirement of basic 
rationality.'').
     Richard J. Pierce, Jr., The Appropriate Role of Costs in 
Environmental Regulation, 54 ADMIN. L.REV. 1237, 1247 (2002) (``All 
individuals and institutions naturally and instinctively consider costs 
in making any important decision . . . . [I]t is often impossible for a 
regulatory agency to make a rational decision without considering costs 
in some way.'')
     the Supreme Court pointed out in Entergy Corp. v. 
Riverkeeper, Inc., 556 U.S. 208, 224 (2009), that the EPA had long 
determined that it was unreasonable to interpret a statute in a way 
``as requiring use of technology whose cost is wholly disproportionate 
to the environmental benefit to be gained.'' (quoting In re Public 
Service Co. of New Hampshire, 1 E.A.D. 332, 340 (1977)). While Entergy 
Corp. was in the context of the Clean Water Act, the same logic applies 
equally here. Justice Breyer reiterated in Entergy Corp., agencies 
should not read statutes in a way that forbids cost-benefit comparisons 
when the language does not require doing so. As Justice Breyer 
explained, not only would that be ``difficult to enforce'' because 
``every

[[Page 42969]]

real choice requires a decisionmaker to weigh advantages against 
disadvantages, and disadvantages can be seen in terms of (often 
quantifiable) costs,'' but such ``absolute prohibition would bring 
about irrational results.''
     the Supreme Court has concluded that ``[n]o regulation is 
`appropriate' if it does significantly more harm than good,'' and 
reminds agencies that ``[c]onsideration of cost reflects the 
understanding that reasonable regulation ordinarily requires paying 
attention to the advantages and the disadvantages of agency decisions 
[reflecting] the reality that too much wasteful expenditure devoted to 
one problem may well mean considerably fewer resources available to 
deal effectively with other (perhaps more serious) problems.'' Michigan 
v. EPA at 752-53 (internal quotations omitted); see also id. (Kagan, J. 
dissenting) (``Cost is almost always a relevant--and usually, a highly 
important--factor in regulation'')
    Response: The EPA disagrees that it was unconditionally obligated 
to consider costs in this CAA section 112(f)(2) risk review. As 
explained in response to a comment in section 1.5 of the document 
titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking, the EPA has the authority to conduct an additional 
risk review, particularly where new information has come to light 
making a prior risk review unreliable. New information became available 
about both chloroprene and EtO in 2010 \36\ and 2016,\37\ respectively. 
After the EPA completed development of the IRIS inhalation URE for 
chloroprene in 2010 and updated the IRIS inhalation URE for EtO in 
2016, the EPA learned that chloroprene and EtO were more toxic than 
previously known. These updates came after the first risk reviews were 
conducted for the SOCMI and Neoprene Production (within the P&R I 
NESHAP) source categories and therefore prompted the EPA to reevaluate 
residual cancer risks caused by EtO and chloroprene emissions.
---------------------------------------------------------------------------

    \36\ U.S. EPA. Toxicological Review of Chloroprene (CASRN 126-
99-8) In Support of Summary Information on the Integrated Risk 
Information System (IRIS). September 2010. EPA/635/R-09/010F. 
Available at: https://iris.epa.gov/static/pdfs/1021tr.pdf
    \37\ U.S. EPA. Evaluation of the Inhalation Carcinogenicity of 
Ethylene Oxide (CASRN 75-21-8) In Support of Summary Information on 
the Integrated Risk Information System (IRIS). December 2016. EPA/
635/R-16/350Fa. Available at: https://cfpub.epa.gov/ncea/iris/iris_documents/documents/toxreviews/1025tr.pdf.
---------------------------------------------------------------------------

    This reevaluation meant that reconsideration of our original 
decisions under CAA section 112(f)(2) for the SOCMI and Neoprene 
Production source categories is warranted, beginning with whether the 
existing standards reduce risks to acceptable levels under the Benzene 
NESHAP. Under the Benzene NESHAP, this meant going through both the (1) 
acceptability and (2) ample margin of safety steps of the section 
112(f)(2) analysis. Only by going through both analytical steps anew 
could the EPA account for the corrected scientific understanding of 
risks from these HAP and conduct the appropriately updated residual 
risk reviews.
    Under the approach outlined in the Benzene NESHAP, National 
Emissions Standards for Hazardous Air Pollutants: Benzene Emissions 
from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene 
Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery 
Plants (54 FR 38,044, September 14, 1989), the EPA evaluates residual 
risk and develops standards under CAA section 112(f)(2) in two steps, 
as some commenters correctly stated. See Proposed Rule, 88 FR at 
25,089. In step (1), the EPA determines whether risks are acceptable 
``consider[ing] all health information, including risk estimation 
uncertainty, and includes a presumptive limit on maximum individual 
lifetime [cancer] risk (MIR) of approximately 1 in 10 thousand.'' 54 FR 
at 38,045. If risks are unacceptable, the EPA must determine the 
emissions standards required to reduce risk to an acceptable level 
without considering costs. In step (2), the EPA considers whether the 
emissions standards provide an ``ample margin of safety'' to protect 
public health ``in consideration of all health information, including 
the number of persons at risk levels higher than approximately 1 in 1 
million, as well as other relevant factors, including costs and 
economic impacts, technological feasibility, and other factors relevant 
to each particular decision.'' Id. (emphasis added). The EPA must then 
promulgate or revise emission standards necessary to provide an ample 
margin of safety to protect public health or determine that the 
standards being reviewed provide an ample margin of safety without any 
revisions. After conducting the ample margin of safety analysis, we 
consider whether a more stringent standard is necessary to prevent, 
taking into consideration costs, energy, safety, and other relevant 
factors, an adverse environmental effect.
    It is true that CAA section 112(f)(2) does not contain words 
declaring that consideration of costs in assessing risk acceptability 
is prohibited. However, this Benzene NESHAP approach was incorporated 
by Congress into CAA section 112(f)(2) in the 1990 CAA amendments and 
was upheld by the United States Court of Appeals for the District of 
Columbia Circuit. See NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 
2008); Proposed Rule, 88 FR at 25,089. The approach is both rational 
and reasonable. While the statute does not expressly forbid 
consideration of costs at step (1), the Benzene NESHAP which the EPA 
promulgated in response to the D.C. Circuit's ruling in NRDC v. EPA, 
824 F.2d 1146 (D.C. Cir. 1987) (Vinyl Chloride),\38\ and Congress's 
endorsement of that approach in enacting the 1990 Amendments to section 
112, have long been understood to prohibit consideration of costs at 
step (1).
---------------------------------------------------------------------------

    \38\ The Vinyl Chloride decision required the EPA to exercise 
its section 112 authority (under the pre-1990 Amendments then in 
effect) in two steps: first, by determining a ``safe'' or 
``acceptable'' level of risk considering only health factors; and, 
second, by setting a standard that provides an ``ample margin of 
safety,'' in which costs, feasibility, and other relevant factors 
also may be considered. 824 F.2d at 1164-65.
---------------------------------------------------------------------------

    The new information gained by the 2010 chloroprene and 2016 EtO 
IRIS inhalation UREs warranted a complete re-analysis of both steps for 
the HON and Neoprene Production rules. The EPA therefore started back 
at step (1), acceptability, in which costs are not considered. Starting 
back at step (1) was essential to ensure that the risks due to EtO and 
chloroprene were being adequately addressed given the EPA's new 
understanding that exposure to EtO and chloroprene poses greater risk 
than was previously known. The EPA could not simply adjust the risk 
review at the step (2) ample margin of safety analysis to correct any 
errors and account for the new understanding. As explained elsewhere in 
this preamble, the EPA has analyzed acceptability of risks from HON and 
Neoprene Production processes under step (1) and identified controls 
necessary to achieve acceptability. Moreover, the EtO and chloroprene 
emission standards for HON and Neoprene Production processes that the 
EPA is promulgating are all necessary to reduce risks from HAP 
emissions from the SOCMI and Neoprene Production source categories to 
acceptable levels, and the EPA is not adopting further source category-

[[Page 42970]]

specific emission standards under CAA section 112(f)(2) under step (2) 
of the Benzene NESHAP. Consequently, the EPA does not agree that the 
cases commenters cited require that the EPA must or even can consider 
costs in determining these risk acceptability-based standards for 
process emissions from these source categories.
    Comment: A commenter argued that the EPA should not be carrying out 
a cost-blind residual risk review for chloroprene when other options to 
address air toxics risks are available that do take costs into 
consideration. The commenter pointed out that on May 6, 2021, the EPA's 
Office of Inspector General (OIG) issued Report No. 21-P-0129: EPA 
Should Conduct New Residual and Technology Reviews for Chloroprene- and 
Ethylene July 7, 2023, 61 Oxide-Emitting Source Categories to protect 
Human Health (``OIG Report''). The commenter said that the EPA's Office 
of Air and Radiation (OAR) submitted three responses to the OIG Report 
in which they reiterated: (1) That they are not statutorily required to 
conduct another residual risk review of chloroprene and (2) that they 
have multiple options to address risks associated with chloroprene that 
do not require a cost-blind residual risk review. The commenter stated 
that OAR explained to OIG that it can consider risks during a 
technology review and that the EPA has ``multiple tools available under 
the CAA for addressing risk from emissions of air toxics'' besides 
discretionary residual risk reviews under CAA section 112(f).
    Other commenters cited various court rulings to support their view 
that the EPA should withdraw the risk review requirements and repropose 
with cost consideration under the technology review provisions of the 
CAA:
     As Justice Kagan noted: ``Unless Congress provides 
otherwise, an agency acts unreasonably in establishing `a standard-
setting process that ignore[s] economic considerations.' '' Id. (Kagan, 
J. dissenting) (quoting Industrial Union Dep't v. American Petroleum 
Institute, 448 U.S. 607, 670 (1980) (Powell, J., concurring in part and 
concurring in judgment)).'' Commenters argue that the approach that 
Justice Kagan warned against is exactly what the EPA has done here.
     the EPA has acted unreasonably, particularly as ``Federal 
administrative agencies are required to engage in ``reasoned decision-
making.'' Allentown Mack Sales & Service, Inc. v. NLRB, 522 U.S. 359, 
374(1998) (internal quotation marks omitted). ``Not only must an 
agency's decreed result be within the scope of its lawful authority, 
but the process by which it reaches that result must be logical and 
rational.''
     It follows that agency action is lawful only if it rests 
``on a consideration of the relevant factors.'' State Farm 463 U.S. at 
43, (internal quotation marks omitted).'' Michigan, 576 U.S. at 750. 
Commenters argue one of those factors is cost.
    Response: As explained above, cost is considered in one of the two 
steps that the EPA undertakes during a residual risk review under 
112(f)(2). The residual risk review is not ``cost-blind.''
    The commenter quotes specific portions of OAR's response to OIG, 
which may not give the full picture of OAR's position in its response. 
For completion, the response stated:
    [I]n those situations where we are reviewing a NESHAP and there is 
new information on the toxicity of a given chemical of interest (and 
the statutorily-required residual risk review has already been 
completed for that source category), we will determine how to best 
consider the new risk information in the current review. As described 
in the roadmaps discussed in our response to Recommendation 2, we will 
evaluate the multiple tools available under the CAA for addressing risk 
from emissions of air toxics. Those tools include conducting a 
discretionary residual risk assessment under CAA section 112(f)(2), 
conducting a review under CAA section 112(d)(6), and/or establishing 
new standards for unregulated pollutants if the original NESHAP did not 
regulate all HAP. We intend to use these tools to reduce risk--
consistent with the law and in a sequence that provides an ample margin 
of safety to protect public health.
    (Emphasis in original.) \39\
---------------------------------------------------------------------------

    \39\ EPA OAR, Response #3 to OIG Final Report at 2-3 (June 1, 
2022) (available at: https://www.epa.gov/system/files/documents/2022-06/_epaoig_21-P-0129_Agency_Response2.pdf).
---------------------------------------------------------------------------

    As OAR stated in the above response, there are multiple tools 
available to ``address'' risk from emissions of air toxics, and OAR 
said it would evaluate those tools, which may include a CAA section 
112(d)(6) review. But the EPA did not say that it commonly 
``considers'' risk in a CAA section 112(d)(6) review, or that risk is a 
factor that must drive a regulatory decision under CAA section 
112(d)(6). The EPA considers the public health and environmental risks 
from HAP emissions during the CAA section 112(f) phase of regulation, 
when the EPA considers any residual risk after technology-based CAA 
section 112(d)(2) standards are implemented. However, when the EPA 
revises standards under CAA section 112(d)(6) and imposes additional 
controls or work practice standards that lead to HAP emission 
reductions, risk from those HAP emission reductions is inherently 
addressed to some degree given that reduced emissions will correlate to 
some degree of reduced risk. While the EPA does not have to directly 
consider risk in the CAA section 112(d)(6) analysis, risks are lowered 
when additional emission controls are imposed as a result of those 
standards.
    However, in the case of the SOCMI and Neoprene Production 
standards, the risks were so significantly affected by the IRIS values 
for EtO and chloroprene that it became clear that a full risk review 
under CAA section 112(f)(2) was warranted, rather than relying on 
ancillary risk benefits that might result from conducting only a CAA 
section 112(d)(6) technology review. Consequently, under the Benzene 
NESHAP approach incorporated by CAA section 112(f), as explained above, 
we had to re-assess whether the existing standards were sufficiently 
protective, and we determined that they did not reduce risks to 
acceptable levels. The standards adopted in the final rulemaking are 
based on what is necessary to reduce risks to acceptable levels under 
the Benzene NESHAP, and therefore may not be based on consideration of 
costs. However, our rulemaking analyses do estimate the costs that will 
result from compliance with the standards, even if that information did 
not drive regulatory decisions. For details on the assumptions and 
methodologies used in the costs and impacts analyses, see the technical 
documents titled Analysis of Control Options for Process Vents and 
Storage Vessels to Reduce Residual Risk of Ethylene Oxide in the SOCMI 
Source Category for Processes Subject to HON; Analysis of Control 
Options for Equipment Leaks to Reduce Residual Risk of Ethylene Oxide 
in the SOCMI Source Category for Processes Subject to HON; Analysis of 
Control Options for Heat Exchange Systems to Reduce Residual Risk of 
Ethylene Oxide in the SOCMI Source Category for Processes Subject to 
HON; Analysis of Control Options for Wastewater Streams to Reduce 
Residual Risk of Ethylene Oxide in the SOCMI Source Category for 
Processes Subject to HON; Analysis of Control Options for Flares to 
Reduce Residual Risk of Ethylene Oxide in the SOCMI Source Category for 
Processes Subject to HON; Analysis of Control Options for Process Vents 
and Storage Vessels to Reduce Residual Risk of Chloroprene Emissions at 
P&R I

[[Page 42971]]

Affected Sources Producing Neoprene; and Analysis of Control Options 
for Wastewater Streams to Reduce Residual Risk of Chloroprene From 
Neoprene Production Processes Subject to P&R I (see Docket Item No. 
EPA-HQ-OAR-2022-0730-0074, -0003, -0071, -0087, -0070, -0083 and -0092, 
respectively).
    Comment: A commenter argued that the Agency arbitrarily fails to 
properly implement the authority it claims to possess. The commenter 
pointed out that the EPA does not limit its review to chloroprene and 
EtO (e.g., in presenting the results of its risk assessment, the EPA 
concludes that maleic anhydride, chlorine, acrylic acid, and 
acrylonitrile present the highest acute inhalation risks for the SOCMI 
source category) even though the EPA claims a second residual risk 
review is only warranted for chloroprene and EtO because of the IRIS 
reassessments. The commenter claimed that the EPA's approach is 
arbitrary and unfounded because the Agency asserts no basis for 
conducting a new risk review for any pollutants other than chloroprene 
and EtO.
    Response: As explained above in response to another comment in this 
section of this preamble, new information about risks of chloroprene 
and EtO exposure has come to light, warranting an updated residual risk 
review for the SOCMI and Neoprene Production (within the P&R I NESHAP) 
source categories. This risk review was conducted in accordance with 
longstanding, congressionally and judicially approved steps laid out in 
the 1989 Benzene NESHAP. Those steps account for the risk due to 
emissions of all HAP from a source category and the risk review is not 
limited to one or two HAP solely because updated risk information is 
available for only two HAP. Therefore, in order to make risk 
acceptability and ample margin of safety determinations for each source 
category, we assessed risks for all HAP emitted by the SOCMI and 
Neoprene Production source categories.
    Importantly, though, the EPA is only imposing new standards under 
CAA section 112(f)(2) to control EtO and chloroprene emissions. The EPA 
is not imposing CAA section 112(f)(2) standards to control maleic 
anhydride, chlorine, acrylic acid, or acrylonitrile in this rulemaking 
and we found no new information regarding the health effects associated 
with these pollutants (like the new information on chloroprene and EtO) 
that would lead us to amend standards for these pollutants under CAA 
section 112(f)(2). Commenters do not provide any explanation, 
therefore, of how they are affected or harmed by the EPA analyzing 
other HAP during this risk review. We have concluded that unacceptable 
risk posed by emissions from these source categories is driven by 
emissions of EtO and chloroprene and we imposed additional standards 
under CAA section 112(f)(2) to reduce emissions of EtO and chloroprene 
to an acceptable level.
    Comment: A commenter argued that given the EPA's failure to 
articulate a legal basis for its position to conduct a second risk 
review violates the Agency's obligation to set forth in a proposed rule 
``the major legal interpretations and policy considerations underlying 
the proposed rule'' according to CAA section 307(d)(3)(c), the 
commenter did not have adequate notice or an opportunity to comment on 
this key issue, which plainly is of central relevance to the rule. The 
commenter asserted that the EPA must supplement the current proposal to 
provide the required legal analysis and provide a reasonable 
opportunity for public comment.
    Response: The EPA explained in the proposed rule that we were 
undertaking an updated residual risk review for the SOCMI and Neoprene 
Production (within the P&R I NESHAP) source categories ``due to the 
development of the EPA's Integrated Risk Information System (IRIS) 
inhalation unit risk estimate (URE) for chloroprene in 2010'' and 
because ``in 2016, the EPA updated the IRIS inhalation URE for EtO.'' 
88 FR at 25083-84.
    The EPA explained that, due to the updated chloroprene information, 
``the EPA conducted a CAA section 112(f) risk review for the SOCMI 
source category and Neoprene Production source category. In the first 
step of the CAA section 112(f)(2) determination of risk acceptability 
for this rulemaking, the use of the 2010 chloroprene risk value 
resulted in the EPA identifying unacceptable residual cancer risk 
caused by chloroprene emissions from affected sources producing 
neoprene subject to P&R I[.] Consequently, the proposed amendments to 
P&R I address the EPA review of additional control technologies, beyond 
those analyzed in the technology review conducted for P&R I, for one 
affected source producing neoprene and contributing to unacceptable 
risk.'' 88 FR at 25083-84.
    Similarly, the EPA explained that, due to updated EtO information, 
``In the first step of the CAA section 112(f)(2) determination of risk 
acceptability for this rulemaking, the use of the updated 2016 EtO risk 
value resulted in the EPA identifying unacceptable residual cancer risk 
driven by EtO emissions from HON processes. Consequently, the proposed 
amendments to the HON also address the EPA review of additional control 
technologies, beyond those analyzed in the technology review conducted 
for the HON, focusing on emissions sources emitting EtO that contribute 
to unacceptable risk.'' 88 FR at 25084.
    The EPA also explained that ``even though we do not have a 
mandatory duty to conduct repeated residual risk reviews under CAA 
section 112(f)(2), we have the authority to revisit any rulemaking if 
there is sufficient evidence that changes within the affected industry 
or significant new scientific information suggesting the public is 
exposed to significant increases in risk as compared to the previous 
risk assessments prepared for earlier rulemakings.'' 88 FR at 25090. 
See also 88 FR at 25111 (``Considering all of the health risk 
information and factors discussed above, particularly the high MIR for 
both the SOCMI and Neoprene Production source categories, the EPA 
proposes that the risks for both source categories are unacceptable. . 
. . [W]hen risks are unacceptable, under the 1989 Benzene NESHAP 
approach and CAA section 112(f)(2)(A), the EPA must first determine the 
emissions standards necessary to reduce risk to an acceptable level, 
and then determine whether further HAP emissions reductions are 
necessary to provide an ample margin of safety to protect public health 
or to prevent, taking into consideration costs, energy, safety, and 
other relevant factors, an adverse environmental effect.'').
    Finally, the scientific and technical bases for the EPA's proposed 
action are voluminously presented in the numerous supporting memoranda 
contained in the public docket for the proposed rulemaking. See, e.g., 
the documents titled Residual Risk Assessment for the SOCMI Source 
Category in Support of the 2023 Risk and Technology Review Proposed 
Rule; Residual Risk Assessment for the Polymers & Resins I Neoprene 
Production Source Category in Support of the 2023 Risk and Technology 
Review Proposed Rule; Analysis of Control Options for Process Vents and 
Storage Vessels to Reduce Residual Risk of Ethylene Oxide in the SOCMI 
Source Category for Processes Subject to HON; Analysis of Control 
Options for Equipment Leaks to Reduce Residual Risk of Ethylene Oxide 
in the SOCMI Source Category for Processes Subject to HON; Analysis of 
Control Options for Heat Exchange Systems to Reduce Residual Risk of 
Ethylene Oxide in the SOCMI Source Category for Processes Subject to 
HON; Analysis of Control Options for Wastewater Streams to

[[Page 42972]]

Reduce Residual Risk of Ethylene Oxide in the SOCMI Source Category for 
Processes Subject to HON; Analysis of Control Options for Flares to 
Reduce Residual Risk of Ethylene Oxide in the SOCMI Source Category for 
Processes Subject to HON; Analysis of Control Options for Process Vents 
and Storage Vessels to Reduce Residual Risk of Chloroprene Emissions at 
P&R I Affected Sources Producing Neoprene; Analysis of Control Options 
for Wastewater Streams to Reduce Residual Risk of Chloroprene From 
Neoprene Production Processes Subject to P&R I; and Analysis of 
Demographic Factors for Populations Living Near Polymers and Resins I 
and Polymer and Resins II Facilities (see Docket Item No. EPA-HQ-OAR-
2022-0730-0085, -0095, -0074, -0003, -0071, -0087, -0070, -0083, -0092, 
and -0060, respectively). Also see the documents titled Analysis of 
Demographic Factors for Populations Living Near Hazardous Organic 
NESHAP (HON) Operations--Final; Analysis of Demographic Factors for 
Populations Living Near Hazardous Organic NESHAP (HON) Operations: 
Whole Facility Analysis--Final; Analysis of Demographic Factors for 
Populations Living Near Neoprene Production Operations--Final; and 
Analysis of Demographic Factors for Populations Living Near Neoprene 
Production Operations: Whole Facility Analysis--Final, which are 
available in the docket for this rulemaking.
    The EPA clearly did articulate its legal position in a manner that 
was sufficient to provide the public a meaningful opportunity to 
comment on the basis for its action, as evidenced by the EPA's receipt 
of comments from several commenters discussing the EPA's use of its CAA 
section 112(f)(2) authority to conduct an updated residual risk review 
and discussing the merits of the risk review. As explained in this 
section, commenters argued on both sides: that the EPA did not have 
authority to conduct the risk review in this rule, or that the EPA must 
conduct additional risk reviews during every 112(d)(6) technology 
review. (See other responses above in this section of this preamble.) 
While comments may not provide the only evidence that a point was 
adequately noticed, ``insightful comments may be reflective of notice 
and may be adduced as evidence of its adequacy.'' Horsehead Dev. Co. v. 
Browner, 16 F.3d 1246 (D.C. Cir. 1994); Nat'l Rest. Ass'n v. Solis, 870 
F. Supp. 2d 42, 52-53 & n.6 (D.D.C. 2012). With thoughtful comments 
from both sides of the issue received here, the EPA has met this test.
d. HON Rule Changes Related To EtO
i. Process Vents and Storage Vessels in EtO Service
    Comment: A commenter said that they supported the EPA's proposed 
definition for ``in ethylene oxide service'' for process vents and the 
sampling and analysis procedures for owners and operators to 
demonstrate that each process vent does, or does not, meet the 
definition. However, other commenters requested the following 
clarifications or revisions to the proposed text:
     the EPA should revise the definition of ``in ethylene 
oxide service'' and the corresponding procedures in 40 CFR 63.109(a) 
for determining whether a process vent is in EtO service so that the 
corresponding 1 ppmv cut-off for process vents in the definition of 
``in ethylene oxide service'' applies on an annual average basis. The 
commenter provided numerous examples showing that EtO concentration in 
the process or the vent stream can vary over time depending on what 
material is being produced.
     the EPA should clarify that the 5 lb/yr EtO mass emission 
rate limit for combined process vents as specified in 40 CFR 
63.113(j)(2), 40 CFR 63.124(a)(4) and (a)(4)(iii), and within the 
definition of ``in ethylene oxide service'' should be on a CMPU-by-CMPU 
basis.
     the EPA should clarify at 40 CFR 63.109(a) that the 
location to measure the EtO concentration for process vents should be 
after the last recovery device (if any recovery devices are present) 
but prior to the inlet of any control device that is present and prior 
to release to the atmosphere to be consistent with requirements 
elsewhere in the HON (e.g., see 40 CFR 63.115(a)).
    Commenters requested that the EPA revise the concentration 
threshold for process vents from 1 ppmv to 3 ppmv or greater and only 
require additional control of process vents that total 100 pounds per 
year or more on an affected source basis. The commenters argued these 
thresholds would alleviate detection limit challenges; and that process 
vents with concentrations and mass emissions rates below these 
thresholds do not significantly contribute to unacceptable risk. A 
commenter pointed out that moisture and interferents will prevent 
obtaining measurements down to 1 ppmv in certain streams such as those 
associated with vacuum distillation operations where motive force is 
provided by steam jet exhaust, and the emission point contains 
primarily steam with potentially trace levels of organic HAP, or in 
streams at the inlet to control devices.
    Response: We acknowledge a commenter's support of the definition 
for ``in ethylene oxide service'' for process vents and the procedures 
for owners and operators to demonstrate that process vent does, or does 
not, meet the definition. However, we are not revising the definition 
in the final rule as requested by other commenters such that it applies 
on an annual average basis. We also disagree with the commenters' 
request to revise the concentration threshold for process vents from 1 
ppmv to 3 ppmv or greater and only require additional control of 
process vents that total 100 pounds per year or more on an affected 
source basis.
    While we agree that the EtO concentration in the process or the 
vent stream can vary over time depending on what material is being 
produced, we consider the corresponding 1 ppmv EtO cut-off for process 
vents reasonable in terms of being measurable and quantifiable, and 
also appropriate for the vent stream characteristics we intended to 
regulate that resulted in risk reductions. We acknowledge every 
facility is different. Some facilities may pose less risks than others, 
but in a densely populated area with a nearby receptor and under 
specific conditions, the risks could none-the-less be unacceptable. In 
order to be protective of public health, we took a conservative 
approach.
    We note that several facilities reported (in response to our CAA 
section 114 request) EtO measurements below 1 ppm; one of these 
measurements is equivalent to greater than 0.5 lb/hr and all other 
measurements below 1 ppm exhibited mass rates less (sometimes much 
less) than 0.02 lb/hr. Given that there do not appear to be detection 
limit challenges based on this recent stack test data, we disagree with 
the commenters' assertion that there is a need to alleviate detection 
limit challenges. Additionally, the 1 ppmv undiluted EtO threshold is 
also used in the Miscellaneous Organic Chemical Manufacturing NESHAP 
(MON) and we are not aware of any detection limit issues within that 
source category.
    With regard to a commenter's request that the 5 lb/yr EtO mass 
threshold for combined process vents be on a CMPU-by-CMPU basis, we 
agree that this was our intent; therefore, we have clarified this in 
the final rule at 40 CFR 63.113(j)(2), 40 CFR 63.124(a)(4) and 
(a)(4)(iii), and within the definition of ``in ethylene oxide 
service.'' Finally, as requested by a commenter, we have clarified at 
40 CFR 63.109(a)(3) that the

[[Page 42973]]

sampling site shall be after the last recovery device (if any recovery 
devices are present) but prior to the inlet of any control device that 
is present and prior to release to the atmosphere.
    Comment: Commenters said that they supported the EPA's proposed 
definition for ``in ethylene oxide service'' for storage vessels and 
the sampling and analysis procedures for owners and operators to 
demonstrate that each storage vessel does, or does not, meet the 
definition. However, some commenters requested the following 
clarifications or revisions to the proposed text:
     the EPA should revise the definition of ``in ethylene 
oxide service'' so that the corresponding the 0.1 percent by weight 
threshold for storage vessels in the definition of ``in ethylene oxide 
service'' applies on an annual average basis. The commenter pointed out 
that this is already allowed for equipment leaks at 40 CFR 
63.109(c)(1); therefore, the EPA could amend the language in 40 CFR 
63.109(b) to consistent with 40 CFR 63.109(c).
     the EPA should add more flexibility to the alternative 
approach in 40 CFR 63.109(b)(2) to allow for good engineering judgment 
and process knowledge similar to the language in 40 CFR 63.109(c)(2) 
for equipment leaks.
     the EPA should revise the definition to refer to ``the 
procedures specified in Sec.  63.109'' instead of ``sampling and 
analysis'' to reduce confusion and eliminate the potential safety 
risks/costs of unnecessary sampling; it is not until proposed 40 CFR 
63.109(b)(2) that the reader is informed that one is allowed to use 
information specific to the stored fluid to calculate the concentration 
of E.O., which does not necessitate sampling.
    A commenter also pointed out that the EPA's proposed definition 
does not comport with the definition discussed in the Agency's 
memorandum which states: ``For storage vessels of any capacity and 
vapor pressure, ``in ethylene oxide service'' means that the 
concentration of ethylene oxide within the tank liquid is greater than 
or equal to 1 ppmw. These definitions exclude ethylene oxide that is 
present as an impurity . . .'' (see Docket Item No. EPA-HQ-OAR-2022-
0730-0074). The commenter requested that the EPA confirm the threshold 
for storage vessels is 0.1 percent by weight, as stated in the red-line 
strike-out version of the proposed rule text, and that the proposed 
definition should not include the phrase: ``The exemption for ``vessels 
storing organic liquids that contain organic hazardous air pollutants 
only as impurities'' listed in the definition of ``storage vessel'' in 
this section does not apply for storage vessels that may be in ethylene 
oxide service.'' Commenters added that the EPA should properly justify 
the 0.1 percent by weight threshold, or revise the threshold to 
eliminate unnecessary additional control of sources that do not pose 
unacceptable risk. The commenters asserted that the risks attributable 
to storage vessels are those storing high concentrations of EtO, not 
vessels storing low concentration materials, making the EPA's proposed 
0.1 percent by weight threshold arbitrary. To address the unnecessary 
burden imposed by the EPA's proposal, the commenters requested the EPA 
revise its analysis such that only those storage vessels that 
significantly contribute to risk (i.e., those storing 100 percent EtO) 
be subject to additional control requirements for EtO.
    Response: The EPA acknowledges a commenter's support of the 
definition for ``in ethylene oxide service'' for storage vessels and 
the procedures for owners and operators to demonstrate that each 
storage vessel does, or does not, meet the definition. However, we are 
not revising the definition in the final rule as requested by other 
commenters such that it applies on an annual average basis; these 
commenters did not provide justification for why this revision is 
needed. We are finalizing the definition as proposed such that a 
storage vessel is considered in EtO service anytime it is storing a 
liquid that is at least 0.1 percent by weight of (or 1,000 ppmw) EtO. 
We consider the 0.1 percent by weight of EtO threshold reasonable in 
terms of being measurable and quantifiable, and also appropriate for 
the vent stream characteristics we intended to regulate that resulted 
in risk reductions. We acknowledge every facility is different. Some 
facilities may pose less risks than others, but in a densely populated 
area with a nearby receptor and under specific conditions, the risks 
could none-the-less be unacceptable. In order to be protective of 
public health, we took a conservative approach. We note that a 1,000 
ppmw threshold corresponds to the chemical inventory reporting 
requirements under the Emergency Planning and Community Right-to-Know 
Act and other supplier notification requirements, so facilities should 
have knowledge of the amount of EtO stored from these sources.
    Regarding the inconsistency between language used in docket item 
EPA-HQ-OAR-2022-0730-0074 versus language used in the red-line strike-
out version of the proposed rule text, we have determined that the 
language used in docket item EPA-HQ-OAR-2022-0730-0074 is an error. In 
other words, we are finalizing the red-line strike-out version of the 
proposed rule text such that the definition does include the phrase: 
``The exemption for ``vessels storing organic liquids that contain 
organic hazardous air pollutants only as impurities'' listed in the 
definition of ``storage vessel'' in this section does not apply for 
storage vessels that may be in ethylene oxide service.'' While we 
believe that emissions from vessels storing impurity levels of EtO are 
very low and do not result in additional risk, we are not providing 
additional constraints or clarifications on the determination of the 
threshold (e.g., providing averaging times) because we anticipate that 
the Emergency Planning and Community Right-to-Know Act and supplier 
notifications will generally be the basis for applicability 
determinations.
    Also, we disagree with the commenters' request to add more 
flexibility to the alternative approach in 40 CFR 63.109(b)(2) for 
storage vessels to be consistent with the equipment leaks provision at 
40 CFR 63.109(c). We believe the rule is already clear regarding 
determining whether storage vessels are ``in ethylene oxide service.'' 
In order to determine the requirements for storage vessels in EtO 
service, facilities must look at both the definition of ``in ethylene 
oxide service'' and the requirements in 40 CFR 63.109 together. The 
definition of ``in ethylene oxide service'' lets the owner or operator 
designate a storage vessel based on process knowledge; however, if an 
owner or operator wants to say a storage vessel is not in EtO service, 
they must use the procedures in 40 CFR 63.109(b). The rule at 40 CFR 
63.109(b)(2) already explicitly allows an avenue for an owner or 
operator to calculate the concentration of EtO of the fluid stored in 
the storage vessels if information specific to the fluid stored is 
available which includes data based on safety data sheets.
    With regard to a commenter's request to change the phrasing of 
``sampling and analysis is performed as specified in Sec.  63.109'' to 
``the procedures specified in Sec.  63.109 are performed'' within the 
definition of ``in ethylene oxide service'' for storage vessels, we 
agree this suggested language is more clear and have revised it in the 
final rule.
    Comment: A commenter said they support the EPA's proposed rule text 
at 40 CFR 63.113(j) that requires owners and operators to reduce 
emissions of EtO from process vents in EtO service by either: (1) 
Venting emissions through a closed-vent system to a control device that 
reduces EtO by greater than or

[[Page 42974]]

equal to 99.9 percent by weight, to a concentration less than 1 ppmv 
for each process vent, or to less than 5 lb/yr for all combined process 
vents; or (2) venting emissions through a closed-vent system to a flare 
meeting the proposed operating and monitoring requirements for flares 
in NESHAP subpart F. The commenter also said they support the EPA's 
proposed rule text at 40 CFR 63.119(a)(5) that requires owners and 
operators to reduce emissions of EtO from storage vessels in EtO 
service by either: (1) Venting emissions through a closed-vent system 
to a control device that reduces EtO by greater than or equal to 99.9 
percent by weight or to a concentration less than 1 ppmv for each 
storage vessel vent; or (2) venting emissions through a closed-vent 
system to a flare meeting the proposed operating and monitoring 
requirements for flares in NESHAP subpart F.
    However, other commenters argued that the EPA should disallow the 
use of flares to control EtO from process vents and storage vessels 
given that flares can only reduce EtO emissions by, at most, 98.6 
percent; and therefore, cannot meet the proposed 99.9 percent by weight 
EtO reduction requirement. The commenters contended that the EPA 
arbitrarily and unlawfully assumes HON sources will use non-flare 
control devices instead of flares to reduce EtO from process vents and 
storage vessels. The commenters added that the Agency's supposition 
that it is ``likely'' that sources will not use flares given the flare 
cap provides no rational or substantial basis for assuming 99.9 percent 
destruction of EtO from process vents and storage vessels. A commenter 
contended that the difference between using a flare and a non-flare 
control device to reduce emissions of EtO from process vents and 
storage vessels could be significant, and provided an example using an 
emissions inventory from 2021 for Indorama's Port Neches plant showing 
this. A commenter asserted that requiring HON sources to use non-flare 
controls (and disallowing the use of flares) to control EtO from 
process vents and storage vessels would not result in additional costs 
beyond those that the EPA has already predicted, since the EPA's cost-
effectiveness analysis assumed that all 12 HON facilities that need to 
control EtO from process vents and storage vessels to reduce risk to 
acceptable levels would install thermal oxidizers.
    The commenters added that unlike the HON, the EPA in its risk 
proposal for Neoprene Production processes subject to the P&R I NESHAP 
(appropriately) proposes to require use of non-flare controls that 
reduce chloroprene by 99.9 percent. The commenters asserted that if the 
EPA were to finalize its proposal to allow HON sources to use flares to 
reduce EtO from process vents and storage vessels (and thus allow 
destruction efficiencies lower than 99.9 percent), this differing 
treatment of risk-driving HAPs from HON and P&R I vents and storage 
vessels would render the Agency's final rule arbitrary and 
capricious.\40\
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    \40\ The commenter cited Transactive Corp. v. United States, 91 
F.3d 232, 237 (D.C. Cir. 1996) (``A long line of precedent has 
established that an agency action is arbitrary when the agency 
offered insufficient reasons for treating similar situations 
differently.'').
---------------------------------------------------------------------------

    Response: We acknowledge a commenter's support for 40 CFR 63.113(j) 
and 40 CFR 63.119(a)(5). We also disagree with other commenters' 
assertions that the EPA must prohibit the use of flares to control EtO 
from process vents and storage vessels. In the proposed rule, we 
recognized flares cannot achieve 99.9 percent EtO reduction and 
proposed an EtO flare load limit. We also noted that as part of the CAA 
section 114 request, six facilities measured EtO emissions from their 
EtO emission points and none of these six facilities currently use a 
flare to control EtO emissions from process vents or storage vessels. 
Even so, our modeling file does include several other HON facilities 
that do use flares to control process vents and storage vessels that 
emit EtO. Therefore, we accounted for these flares operating at 98 
percent EtO reduction in our risk assessment, proposed an EtO flare 
load limit, and determined that it is not necessary for flares to 
achieve 99.9 percent EtO reduction in order to reduce risk to an 
acceptable level and provide an ample margin of safety to protect 
public health (provided that owners and operators still comply with the 
entire suite of EtO control requirements that we are finalizing in the 
rule). However, in response to a comment addressed in section 
IV.A.3.d.v of this preamble we are not including an EtO flare load 
limit in the final rule; and we determined that risks are acceptable 
for flares operating at 98 percent EtO reduction and flares operating 
at 98 percent EtO reduction provide an ample margin of safety to 
protect public health, without the need for an EtO flare load limit.
    Also, to the commenter's assertion that the EPA is giving differing 
treatment between HON process vents and storage vessels and P&R I 
process vents and storage vessels, we note that in the final rule, we 
require use of non-flare controls to reduce chloroprene by 98 percent 
\41\ (i.e., we prohibit the use of flares to control chloroprene in the 
Neoprene Production source category) because dioxins and furans can be 
formed when chlorinated compounds (i.e., chloroprene) are present and 
combusted, and the more consistent combustion of non-flare controls 
such as thermal oxidizers is more appropriate than flares to reduce 
dioxin and furan formation. Dioxin and furan formation is not a concern 
when combusting EtO in a flare.
---------------------------------------------------------------------------

    \41\ In response to a comment in section IV.A.3.e.i of this 
preamble, we are revising the performance standard for process vents 
and storage vessels in chloroprene service (from a 99.9 percent by 
weight reduction requirement as proposed to a 98 percent by weight 
reduction requirement in the final rule).
---------------------------------------------------------------------------

ii. Equipment Leaks in EtO Service
    Comment: A commenter said that they supported the EPA's proposed 
definition for ``in ethylene oxide service'' for equipment leaks and 
the sampling and analysis procedures for owners and operators to 
demonstrate that process equipment does, or does not, meet the 
definition. However, some commenters requested the EPA revise the 0.1 
percent by weight threshold to 5.0 percent by weight.
    A commenter argued that most of EtO emissions from equipment leaks 
come from piping that has an EtO concentration of 5.0 percent by weight 
or higher. The commenter contended that expanding the new regulatory 
provisions to streams containing EtO between 0.1 and 5.0 percent by 
weight will result in a much more stringent LDAR program for components 
that are primarily in ethylene, methane, nitrogen, and carbon dioxide 
(CO2) service, and will have a minimal to negligible impact 
on reducing the fugitive emissions of EtO and the resulting residual 
risk. The commenter also recommended that the EPA revise 40 CFR 
63.109(c)(1) and (2) to reflect the 5.0 percent by weight threshold 
instead of the 0.1 percent by weight threshold.
    Other commenters asserted that the EPA does not explain why a 0.1 
percent by weight threshold of EtO in equipment presents unacceptable 
risk; the commenters said based on their revised risk modeling 
assessment (including their recommended revisions to the HEM4 modeling 
file inputs such as revised flare parameterization, updates provided by 
companies, and removal of one time/infrequent release events), 
equipment containing less than 5 percent EtO does not significantly 
contribute to risk, nor is it cost-effective when considered in the 
context of an ample margin of safety analysis.

[[Page 42975]]

    A commenter added that the EPA should revise the definition to 
refer to ``the procedures specified in Sec.  63.109'' instead of 
``sampling and analysis'' to reduce confusion and eliminate the 
potential safety risks/costs of unnecessary sampling; it is not until 
proposed 40 CFR 63.109(c)(2) that the reader is informed that one is 
allowed to use engineering judgment to determine the EtO concentration 
of the process fluid, which does not necessitate sampling.
    Response: The EPA acknowledges a commenter's support of the 
definition for ``in ethylene oxide service'' for equipment leaks and 
the procedures for owners and operators to demonstrate that process 
equipment does, or does not, meet the definition. However, we reject 
other commenters' requests to revise the 0.1 percent by weight 
threshold to 5.0 percent by weight. As discussed in the preamble to the 
proposed rule (see 88 FR 25080, April 25, 2023), results from our risk 
assessment indicate that, for the source category MIR of 2,000-in-1 
million, approximately 20 percent is from emissions of EtO related to 
HON equipment leaks. We also note that the risk from EtO from HON 
equipment leaks at seven facilities (including the facility driving the 
MIR) is >=100-in-1 million. To help reduce the risk from the SOCMI 
source category to an acceptable level, for EtO emissions from HON 
equipment leaks, we performed a review of available measures for 
reducing EtO emissions from components that are most likely to be in 
EtO service, which include connectors (in gas and vapor service or 
light liquid service), pumps (in light liquid service), and valves (in 
gas or light liquid service). Almost all EtO emissions related to 
equipment leaks come from these three pieces of equipment.
    We considered the proposed 0.1 percent by weight threshold 
reasonable in terms of being measurable and quantifiable, and also 
appropriate for the vent stream characteristics we intended to regulate 
that resulted in risk reductions. We acknowledge every facility is 
different. Some facilities may pose less risks than others, but in a 
densely populated area with a nearby receptor and under specific 
conditions, the risks could none-the-less be unacceptable. In order to 
be protective of public health, we took a conservative approach. 
Regarding comments that there is no justification for adding additional 
controls for low risk sources given the cost, in codifying the Benzene 
NESHAP approach CAA section 112(f)(2) does not allow us to consider 
cost at the first step of the residual risk analysis in identifying 
what standards are needed to reduce unacceptable risk to an acceptable 
level, and at proposal, and in the final rule, we determined that prior 
to application of the control requirements being finalized, the risk 
was unacceptable. It is only if the EPA adopts more stringent standards 
to further reduce emissions and reduce risks below acceptable levels if 
needed to provide an ample margin of safety to protect public health, 
at the second step of the residual risk analysis, that costs may be 
considered among other relevant factors.
    With regard to a commenter's request to change the phrasing of 
``sampling and analysis is performed as specified in Sec.  63.109'' to 
``the procedures specified in Sec.  63.109 are performed'' within the 
definition of ``in ethylene oxide service'' for equipment leaks, we 
agree this suggested language is more clear and have revised it in the 
final rule.
    Comment: Several commenters objected to the EPA's proposal at 40 
CFR 63.171(f) that does not allow delay of repair for equipment in EtO 
service.
    Commenters contended that the EPA did not consider the cost 
associated with more frequent and/or longer outage times due to removal 
of the delay of repair option. Commenters stated that most valves and 
connectors are not configured with in-line spares; and if a repair 
requires replacement of a leaking component, the equipment must be 
isolated, and in certain instances the entire process unit must be 
shutdown. Commenters contended that additional shutdowns directly 
increase the likelihood of future leaks given that each shutdown and 
startup cycle subjects equipment to pressure and temperature changes 
that could negatively impact equipment reliability.
    Commenters added that, often, valves or other connectors may not be 
``off the shelf'' so that a facility would be required to special order 
and wait on the equipment to arrive while shutdown. A commenter stated 
that lead up times to shutdowns typically provide adequate time for 
facilities to order and test components; however, if the delay of 
repair provisions are eliminated, required lead times for these 
activities will result in extended shutdowns. The commenter also said 
that facilities must often carefully evaluate the safety considerations 
of ``boxing in'' leaking EtO equipment due to the tendency of stagnant 
EtO to polymerize which can render equipment such as control valves 
inoperable. The commenter continued that it is often necessary to 
evaluate and engineer a clamp style solution, a process that can take 
more than the allotted 15-day repair time.
    Commenters also noted additional consequences of more frequent 
shutdowns including additional wear on rotating equipment, and reduced 
catalyst life which could result in emission increases and waste 
generation.
    A commenter argued that eliminating delay of repair would generally 
require a first repair attempt within 5 days of detection, which is an 
infeasibly short amount of time to safely shutdown one process unit, 
much less multiple integrated units. The commenter stated that delay of 
repair provides facilities with time needed to plan and prepare for a 
shutdown, which minimizes the safety risks that inevitably accompany 
shutdowns and startups. The commenter added that being required to 
shutdown abruptly and more frequently will unnecessarily increase 
safety risks to employees with minimal environmental benefit. The 
commenter said that they follow standard industry procedures in 
preparing for a scheduled shutdown, which involves adequate preparation 
time and personnel to completely purge of all lines containing EtO, 
using appropriate controls, before shutdown. The commenter said that 
stagnant EtO polymerizes, creating heat that can cause explosions.
    Commenters argued that an increase in number of shutdowns due to 
the EPA eliminating delay of repair for equipment in EtO service could 
also result in impact to supply chain. A commenter said that supply 
chain disruptions pose significant economic, security and health risks. 
Another commenter added that impacts on supply could well impact 
broader EPA and Administration priorities such as the EPA's recent 
proposal to electrify motor vehicles which is dependent upon EV battery 
production (and such battery production is currently generally 
dependent upon ethylene carbonate, which is produced by reacting EtO 
with CO2).
    Commenters contended that the EPA failed to explain how eliminating 
delay of repair for equipment in EtO service would reduce EtO emissions 
or risks. Commenters argued that eliminating the delay of repair 
provisions results in an increase in emissions due to more frequent 
shutdowns. Commenters contended that without the ability to delay 
repair, it will result in unplanned shutdowns which will result in 
greater emissions as emissions are expected to be higher during 
shutdown than emissions from components on delay of repair. A commenter 
said EtO emissions can range from approximately 5 to 340 lbs per 
shutdown event and provided calculations showing that a repair of a

[[Page 42976]]

leaking valve would have to be delayed for over 10 years before the 
emissions exceeded those generated by a CMPU shutdown that resulted in 
85 lbs of EtO emissions. Some commenters pointed out that delay of 
repair provisions allow facilities to assess whether allowing a small 
leak to continue poses less risk and concern than the emissions 
necessarily associated with a shutdown.
    A commenter argued that they would expect only a small number of 
component(s) in EtO service to use the delay of repair provisions at 40 
CFR 63.171 given that HON CMPUs that produce and use EtO as a raw 
material will typically have a planned process shutdown every 2 to 3 
years depending on the specific process.
    Another commenter suggested that the EPA adopt the TCEQ delay of 
repair program as described in 30 Texas Administrative Code (TAC) 
115.352(2): If the repair of a component within 15 days after the leak 
is detected would require a process unit shutdown that would create 
more emissions than the repair would eliminate, the repair may be 
delayed until the next scheduled process unit shutdown. The commenter 
argued that the TCEQ requirement is reasonable given that it allows 
companies to choose the lowest-emitting option and attain the goal of 
minimizing emissions.
    Response: Regarding commenters' assertions about cost and timing of 
repair, with one exception, we are finalizing the proposed requirements 
for delay of repair for equipment in EtO service pursuant to CAA 
section 112(f)(2), on the basis of risks being unacceptable. Where we 
find risks are unacceptable, the EPA must determine the emissions 
standards necessary to reduce risk to an acceptable level. The largest 
contributor to risk from EtO facilities is due to emissions from 
equipment leaks. Because emissions of EtO from the SOCMI source 
category result in unacceptable risks, we proposed and are finalizing 
requirements that would reduce risks to an acceptable level, including 
provisions not allowing a delay of repair for equipment in EtO service. 
Allowing delay of repair would allow increased emissions of EtO and 
increased risk. The one exception is that we are revising 40 CFR 
63.171(b) to allow a delay of repair for equipment if the equipment is 
isolated from the process and does not remain in organic HAP service.
    To the commenters' assertions that increased startup and shutdown 
events will lead to additional EtO emissions, we disagree. First, we 
have removed the exemptions for periods of SSM. As a result, facilities 
must be in compliance with the rule requirements at all times and must 
control EtO emissions at all times. Therefore, while there may be 
additional EtO entering the control device as a result of SSM, the 
finalized control provisions ensure risk remains acceptable. Second, we 
are finalizing maintenance vent requirements which are intended to 
address equipment openings that result from startup, shutdown, 
maintenance, or inspection of equipment where equipment is emptied, 
depressurized, degassed, or placed into service. We are finalizing that 
owners and operators may not release more than 1.0 ton of EtO from all 
maintenance vents combined per any consecutive 12-month period. An 
owner or operator may designate any process vent as a maintenance vent 
if the vent is only used as a result of startup, shutdown, maintenance, 
or inspection of equipment where equipment is emptied, depressurized, 
degassed, or placed into service. Thus, shutdowns resulting from the 
identification of leaks could be included under the 1.0 tpy EtO limit. 
It is the responsibility of the owner or operator to plan accordingly 
for equipment replacement and minimizing safety risks during shutdowns. 
Third, using the commenters' estimates of EtO emissions ranging from 5 
to 340 lbs per shutdown event, the number of shutdowns that could fall 
under the 1 tpy limit could range from almost 6 to 400. Given the 
typical leak rates seen by industry (as discussed in our responses to 
comments in section 2.2 of the document titled Summary of Public 
Comments and Responses for New Source Performance Standards for the 
Synthetic Organic Chemical Manufacturing Industry and National Emission 
Standards for Hazardous Air Pollutants for the Synthetic Organic 
Chemical Manufacturing Industry and Group I & II Polymers and Resins 
Industry, which is available in the docket for this rulemaking) and the 
variety of process conditions, the EPA believes that it would be 
unlikely for a facility to develop 5 leaks at the maximum estimated EtO 
levels warranting shutdown events. We note that even if a facility were 
to reach the 1.0 tpy maintenance vent limit, they may still shutdown to 
repair leaking equipment so long as the emissions are controlled.
    Comment: In response to the EPA soliciting comments on alternative 
monitoring technologies, a commenter supported optical gas imaging 
(OGI) be used as an option to find larger equipment leak air emissions 
and to repair leaks, and that perhaps it could be used in conjunction 
with an annual connector monitoring program for connectors in EtO 
service. Another commenter contended that the EPA failed to include 
LDAR alternatives for use of OGI despite the agency's recognition of 
its efficacy in the recent NSPS subpart OOOOb and EG subpart OOOOc 
proposed rules and development of Appendix K, which specifically states 
it is the methodology that the EPA plans to incorporate by reference in 
the different NSPS/NESHAP subparts to enable implementation of this 
technology. The commenter contended that the EPA should correct this 
inconsistency. A commenter recommended that if the EPA determines OGI 
is an appropriate option to include in the final rule, the EPA model 
the specific OGI requirements after those contained in NSPS subpart 
OOOOa at 40 CFR 60.5397a(c)(7) and (d)(1) that address fugitive 
emissions monitoring plans where OGI is used and the requirements in 40 
CFR 60.5397a(h)(4)(iv) that address resurveying equipment to verify 
repair. The commenter noted that some of the requirements in NSPS 
subpart OOOOa relative to OGI monitoring will need to be adjusted to 
account for application of OGI to a CMPU and not an oil and gas 
production site, as there are more potential interferences in a CMPU.
    Another commenter contended that the EPA has not clearly addressed 
the use of any alternative work practices for fugitive monitoring such 
as OGI but is soliciting technical justification to include or exclude 
OGI as an option for the proposed low (100 ppmv) detection levels using 
EPA Method 21. The commenter added that this low concentration has not 
been evaluated as a level which can be observed reliably and 
consistently with an OGI camera. The commenter requested that any 
technical evaluation and proposed outcome be re-published as a proposal 
to ensure comprehensive evaluation by all potentially affected parties 
and authorities. The commenter concluded that the EPA should not 
collect comments, complete a review, and make a final rule change 
without further opportunity for comment.
    A commenter stated that based on publicized research, including the 
EPA's Optical Gas Imaging Appendix K Technical Support Document, there 
is a known variability of response factors within chemical plant gas 
streams and the detection/sensitivity ranges of OGI technology versus 
legacy technologies. The commenter noted that case-by-case permits have 
been issued with an OGI alternative; however, each of these

[[Page 42977]]

permits has incorporated an annual EPA Method 21 survey to ensure that 
all components have been properly evaluated for leaks, and the 
commenter recommended adding this requirement for any OGI alternative 
for these sites.
    A commenter noted that the results obtained using OGI for leak 
detection can be heavily influenced by instrument performance, 
environmental conditions, and human factors. The commenter explained 
that weather conditions such as ambient temperature, wind speed, or 
wind direction relative to the observer may affect the apparent 
concentration of any leak when viewed with OGI. The commenter stated 
that a study of OGI for detection of natural gas leaks found that only 
51 percent of leaks were detected at wind speeds above 21 miles per 
hour. The commenter opined that higher concentrations of gas streams 
may be needed for detection to occur with OGI technology, especially as 
it applies to OGI surveys within the chemical sector, whereas the 
annual EPA Method 21 survey ensures a quantitative measurement and more 
appropriately demonstrates compliance. The commenter requested the EPA 
clarify if it plans to include the proposed Appendix K or another 
monitoring protocol for OGI to be followed so that there are clear and 
consistent expectations of field experience for camera operators 
including operator training, component dwell time, required operator 
breaks, and other criteria which are not addressed in 40 CFR 63.11.
    Response: We disagree with the commenters that stated the rules 
should have required the use of OGI. The SOCMI has been complying with 
equipment leak regulations since the early 1980s, and leaks are much 
smaller than those found in the oil and gas industry. As a result, the 
leak definitions that SOCMI facilities are complying with are in the 
area of 500 to 1000 ppm for most equipment, and the proposed and final 
rule lowers leak definitions to 100 ppm for valves and connectors in 
EtO service. We acknowledge that OGI is effective at finding large 
leaks quickly for many compounds. OGI is less effective at finding low-
level leaks, especially in the environmental conditions that generally 
exist during a field survey. As a commenter indicated, the low leak 
concentrations that were proposed and which we are finalizing (100 ppm) 
have not been evaluated at a level which can be observed reliably and 
consistently with an OGI camera. In feasibility studies conducted as 
part of the development of 40 CFR part 60 appendix K,\42\ which are the 
procedures for using OGI in leak detection, leaks below 500 ppm (or 
even higher in some circumstances) could not be reliably detected even 
in a laboratory setting except under the most ideal conditions. We also 
agree with the commenter who noted that leak detection with an OGI 
camera is heavily influenced by environmental conditions and human 
factors. Additionally, as explained more fully in response to a comment 
in section IV.B.3.b.ii of this preamble, OGI cameras, especially in the 
most common filter bandwidths, are not sensitive to some of the 
chemicals found at SOCMI facilities, which can make leaks difficult or 
even impossible to see, even for large leaks. In promulgating NSPS 
subpart OOOOb and EG subpart OOOOc, the EPA considered the level of 
control required for fugitive emissions in the oil and natural gas 
sector, as well as the chemical make-up of the expected fugitive 
emissions. Based on those considerations, we determined that OGI was a 
viable option for facilities subject to regulation under those subparts 
through our BSER analysis. However, for the reasons outlined in this 
response, while the use of OGI is appropriate for the oil and natural 
gas sector, it would not be appropriate to rely exclusively upon OGI 
for the SOCMI source category.
---------------------------------------------------------------------------

    \42\ See 89 FR 16820 (March 8, 2024).
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iii. Heat Exchange Systems in EtO Service
    Comment: A commenter said that they supported the EPA's proposed 
definition for ``in ethylene oxide service'' for heat exchange systems 
and the sampling and analysis procedures for owners and operators to 
demonstrate that each heat exchange system does, or does not, meet the 
definition. However, commenters requested the following clarifications 
or revisions to the proposed text:
     the EPA should add into the definition an exclusion for 
EtO present as an impurity consistent with the Agency's memorandum 
which states: ``This definition excludes ethylene oxide that is present 
as an impurity.'' (see Docket Item No. EPA-HQ-OAR-2022-0730-0074).
     the EPA should revise 40 CFR 63.109(e) to allow the 
ability to use good engineering judgment to determine the percent of 
EtO in the process fluid as they have for equipment leaks in 40 CFR 
63.109(c)(2). The commenters said that process fluids serviced by heat 
exchange systems are the same process fluids contained in equipment 
that must be evaluated for ``in ethylene oxide service,'' and this 
prohibition negates the cost savings and flexibility allowed by the use 
of good engineering judgment for equipment leaks because facilities 
will be required to conduct sampling and analysis on the same process 
streams regardless under the heat exchange system provisions. The 
commenters added that sampling and analyzing process fluids subject to 
the monitoring requirements for heat exchange systems presents the same 
issues and difficulties that the EPA identified as the basis for 
allowing engineering judgment under the MON RTR.
     the EPA should consider allowing facilities to account for 
site-specific conversion of EtO to ethylene glycol in water in heat 
exchange systems based on the characteristics (e.g., temperature and 
pH) of the heat exchange system in determining the threshold 
definition.
    Some commenters requested the revise the 0.1 percent by weight 
threshold to at least 0.5 percent by weight. These commenters argued 
that a heat exchanger with an industry-average flow rate with a leak 
rate of 3.6 ppmw and a process fluid concentration of 0.5 percent EtO 
would not pose unacceptable risk if the leak were to occur for 135 days 
as allowed by the existing heat exchange system monitoring provisions 
(i.e., quarterly sampling plus a 45-day repair period). A commenter 
asserted that the EPA does not explain why a 0.1 percent by weight 
threshold of EtO in process fluid presents unacceptable risk.
    Response: We acknowledge the commenter's support of the definition 
for ``in ethylene oxide service'' for heat exchange systems and the 
procedures for owners and operators to demonstrate that each heat 
exchange system does, or does not, meet the definition. However, we 
disagree with other commenters' requests to revise the 0.1 percent by 
weight threshold to at least 0.5 percent by weight. We consider the 0.1 
percent by weight threshold reasonable in terms of being measurable and 
quantifiable, and also appropriate for heat exchange system leak 
characteristics we intended to regulate that resulted in risk 
reductions. We acknowledge every facility is different. Some facilities 
may pose less risks than others, but in a densely populated area with a 
nearby receptor and under specific conditions, the risks could none-
the-less be unacceptable. In order to be protective of public health, 
we took a conservative approach.
    We agree to the commenter's request to allow the ability to use 
good engineering judgment at 40 CFR 63.109(e) to determine the percent 
of

[[Page 42978]]

EtO of the process fluid cooled by the heat exchange system similar to 
what we have allowed for equipment leaks in 40 CFR 63.109(c)(2). We are 
making this change in the final rule due to the difficulty and issues 
with sampling and testing fluid in process lines, particularly if the 
fluid contains EtO. Also, we believe the use of site-specific 
conversion calculations of EtO to ethylene glycol in heat exchange 
systems already qualifies as good engineering judgment using 
calculations based on process stoichiometry; however, due to its 
relation to risk as previously discussed, the threshold for determining 
if equipment is ``in ethylene oxide service'' is not being revised per 
the commenter's request.
    Regarding the language used in docket item EPA-HQ-OAR-2022-0730-
0074 versus it not being included in the red-line strike-out version of 
the proposed rule text, we have determined that the language used in 
docket item EPA-HQ-OAR-2022-0730-0074 is an error. In other words, we 
are finalizing the red-line strike-out version of the proposed rule 
text and are not including an exclusion for EtO present as an impurity. 
The 0.1 percent by weight threshold already accounts for impurities.
    Comment: A commenter said they support the EPA's proposed rule text 
at 40 CFR 63.104(g)(6) and (h)(6) that requires owners and operators to 
conduct more frequent leak monitoring (weekly instead of quarterly) for 
heat exchange systems in EtO service and repair leaks within 15 days 
from the sampling date (in lieu of the current 45-day repair 
requirement after receiving results of monitoring indicating a leak in 
the HON), and delay of repair would not be allowed.
    However, other commenters raised the following concerns with regard 
to sampling frequency and delay of repair. Commenters recommended that 
the EPA modify the proposed 40 CFR 63.104(g)(6) to require monthly (in 
lieu of weekly) sampling via the Modified El Paso Method. A commenter 
contended that weekly monitoring of each heat exchange system will 
require either multiple sampling apparatuses or frequent movement of 
the sampling apparatus from one system to another. Similarly, another 
commenter argued that weekly sampling presents some logistical problems 
as typically a contractor brings in the monitoring device, which is a 
skid mounted unit; the contractor will then move the device from one 
sampling location to additional sampling locations at the site. In some 
cases, the commenter said that the monitoring skid must be moved to 
other process areas that are subject to the other rules such as the 
Ethylene MACT and the MON rule; therefore, a requirement to conduct 
this type of monitoring on a weekly basis will limit the flexibility to 
move the monitoring skid at the site.
    The commenters suggested that the monthly Modified El Paso Method 
monitoring could be combined with weekly analysis of a surrogate 
parameter as an alternative to conducting weekly sampling using the 
Modified El Paso Method. The commenters said that the surrogate 
parameter could be something like monitoring weekly using a water 
analytical method to indicate the presence of a leak or monitoring 
other parameters that would indicate the presence of a leak; and if a 
surrogate measurement indicates a leak, the facility would be required 
to confirm the presence of the leak using the Modified El Paso Method 
and repair as required by the proposed provisions.
    A commenter requested that the EPA not eliminate the option that 
allows facilities to delay the repair provided emissions from the 
process shutdown needed to repair the leak are greater than the 
potential emissions of delaying. The commenter said that this option 
essentially allows facilities to repair the leak with as little 
emissions and environmental impact as possible by requiring the 
facility to evaluate the emissions of a continued leak against the 
emissions from an entire process shutdown. The commenter claimed that 
allowing a repair to be delayed until the next process unit shutdown, 
if emissions from the delay would be less than those from the unplanned 
shutdown itself, has been a longstanding concept in several chemical 
sector rules (see for example 40 CFR 60.482-9(c), 63.104(e)(2)(i), 
63.171(c), 63.1024(d)(3), and 63.105(d)(3)). The commenter contended 
that by forcing facilities to repair leaks solely based on a 
concentration-based threshold, facilities with a smaller recirculation 
rate will likely emit greater amounts of HAP than if they were allowed 
to assess the overall mass emissions from the leak versus shutdown and 
choose the option that minimizes emissions.
    The commenter also said that it is unclear why the EPA is proposing 
to not allow facilities to delay a repair by isolating the equipment 
such that it is no longer in EtO service. The commenter said that in 
certain instances, a facility may be able to isolate a leaking heat 
exchanger but cannot open the equipment until a process unit shutdown.
    Response: We acknowledge the commenter's support of the rule text 
at 40 CFR 63.104(g)(6) and (h)(6) that requires owners and operators to 
conduct more frequent leak monitoring (weekly instead of quarterly) for 
heat exchange systems in EtO service and repair leaks within 15 days 
from the sampling date (in lieu of the current 45-day repair 
requirement after receiving results of monitoring indicating a leak in 
the HON), and delay of repair would not be allowed.
    However, we disagree with other commenters' request to require 
monthly (in lieu of weekly) sampling via the Modified El Paso Method. 
As we stated in the document titled Analysis of Control Options for 
Heat Exchange Systems to Reduce Residual Risk of Ethylene Oxide in the 
SOCMI Source Category for Processes Subject to HON (see Docket Item No. 
EPA-HQ-OAR-2022-0730-0071), we determined baseline EtO emissions and 
emissions reductions using information the EPA received from Union 
Carbide Corporation-Seadrift, TX about an EtO emissions event (Incident 
293911) that was reported to the TCEQ on October 21, 2018. Using 
information provided, we calculated different sampling and repair 
periods required to reduce risks to an acceptable level. Because at 
least a 90+ percent reduction in EtO emissions is needed to get to this 
level (as the risk posed by this large leak is at least 400-in-1-
million based on current the HON standards and Union Carbide's best 
case emissions estimates and because other emission sources also 
contribute to risks), we determined that if the facility identifies and 
repairs an EtO leak (from a heat exchange system) within 15 days from a 
weekly sampling event, the facility would achieve a 6.06 tpy EtO 
emission reduction (i.e., 93 percent reduction in EtO emissions). Less 
frequent sampling (e.g., monthly) and more time to repair the leak from 
the sampling period does not get to the level of reduction needed to 
bring facility risk to below 100-in-1 million. We also noted that the 
facility indicated they are currently conducting weekly sampling for 
leaks of EtO already and have implemented this type of sampling across 
all their facilities that have heat exchange systems cooling process 
streams with EtO.
    In addition, we also reject the commenters' request to use a weekly 
analysis of a surrogate parameter as an alternative to conducting 
weekly sampling using the Modified El Paso Method. Surrogate methods 
via water analysis are less sensitive than the Modified El Paso Method. 
Therefore, though weekly monitoring via a

[[Page 42979]]

surrogate would catch the largest of leaks, there would still be the 
potential for leaks to go uncaptured until the next monthly check via 
the Modified El Paso Method. As a result, to keep risk at an acceptable 
level, we maintain that weekly monitoring via the Modified El Paso 
Method is appropriate.
    Similarly, we reject a commenter's request to allow delay of repair 
at 40 CFR 63.104(h)(6) for heat exchange systems in EtO service. As 
previously discussed, our leak analysis is based on reducing the delay 
of repair to achieve a cancer risk incidence at or below 100-in-1 
million. Given that EtO is a major cancer driver, leaks need to be 
addressed quickly to keep risk at an acceptable level. Having said 
this, we agree with the commenter that owners and operators should be 
allowed to delay a repair by isolating the equipment (e.g., a heat 
exchanger) such that it is no longer in EtO service. It was our intent 
to allow this type of delay of repair which has always been allowed in 
the HON at 63.104(e). In this scenario, the owner and operator may 
delay repair indefinitely as there is no longer an active EtO leak once 
the equipment is isolated and not in EtO service. For this reason, we 
are revising 40 CFR 63.104(h)(6) in the final rule to include the 
following allowance: ``Delay of repair of heat exchange systems in 
ethylene oxide service for which leaks have been detected is allowed if 
the equipment is isolated from the process such that it is no longer in 
ethylene oxide service.''
iv. Wastewater in EtO Service
    Comment: A commenter said that they supported the EPA's proposed 
definition for ``in ethylene oxide service'' for wastewater and the 
sampling and analysis procedures for owners and operators to 
demonstrate that each wastewater stream does, or does not, meet the 
definition. However, other commenters requested the EPA reevaluate the 
1 ppmw EtO concentration threshold for wastewater control. These 
commenters contended that the EPA should make the EtO concentration 
threshold less stringent (i.e., a value >1ppmw EtO) primarily on the 
basis that wastewater should not be regulated more strictly than 
process vents, there is negligible additional benefit for excessive 
complexity controlling down to 1 ppmw, and the majority of wastewater 
collection and treatment emissions will be captured even with a less 
stringent EtO concentration threshold for wastewater control. The 
commenters said the EPA does not state why a 1 ppmw threshold is 
necessary to reduce risks or provide an ample margin of safety, or why 
Group 1 streams should be classified based solely on this concentration 
threshold. The commenters recommended the EtO concentration threshold 
for wastewater control should be changed to an annual average 
concentration of either 25 or 27 ppmw EtO with an annual average flow 
rate of 10 liters per minute or higher (in lieu of proposing a no flow 
rate threshold).
    Additionally, commenters requested the EPA establish a mass 
threshold for wastewater as a ``de minimis'' value to prevent having to 
control very small or low flow intermittent wastewater streams that 
provide little risk reduction, and to raise the concentration 
commensurate with other rules. A commenter recommended the cutoff for 
each wastewater stream be a total annual average mass flow rate of EtO 
to the sewer of at least 0.01 lb/min (0.6 lb/hr). Other commenters 
requested the EPA add a cutoff such that none of a facility's process 
wastewater streams should be considered in EtO service if the entire 
collection of EtO-containing process wastewater streams from HON CMPUs 
contain no more than 0.24 tpy of EtO. Commenters pointed out that when 
reviewing the responses to the EPA's CAA section 114 request, typically 
only one existing Group 2 wastewater stream contributes the majority of 
the EtO baseload flow to the sewer system; and there are other process 
wastewater streams in which the EtO concentration is between 1 and 15 
ppmw, and the flowrate of the stream is very low or very intermittent, 
resulting in flows to the sewer systems that are in some cases less 
than 0.1 lb/hr or even much lower. The commenters argued that it does 
not make sense to require Group 1 controls for these low volume streams 
as one is essentially treating almost pure water at this point.
    Response: The EPA acknowledges commenters' support and opposition 
to revise the Group 1 wastewater stream threshold to include wastewater 
streams in EtO service (i.e. wastewater streams with total annual 
average concentration of EtO greater than or equal to 1 ppmw at any 
flowrate). We are finalizing the definition of ``in ethylene oxide 
service'' definition for wastewater as proposed. With regard to the 
commenters' assertion that the 1 ppmw threshold was not explained, the 
document titled Analysis of Control Options for Wastewater Streams to 
Reduce Residual Risk of Ethylene Oxide in the SOCMI Source Category for 
Processes Subject to HON (see Docket Item No. EPA-HQ-OAR-2022-0730-
0087) states that a 1 ppmw threshold is necessary to reduce risk of EtO 
emissions from wastewater, as the risk due to wastewater is as high as 
200-in-1-million, which contributes to unacceptable risk. Additionally, 
the data from our CAA section 114 request shows that introducing a 
flowrate threshold, as one commenter suggested, would leave wastewater 
streams with large amounts of EtO uncontrolled, and could contribute to 
increased risk at some facilities over 100-in-1-million.
    Similarly, we disagree with the commenters' suggestion to include a 
mass threshold. We calculated the maximum amount of EtO emissions from 
wastewater streams that would push a facility over the 100-in-1-million 
mark, and found the lowest amount of excess EtO emissions to be 0.06 
tpy. This is well under the commenters' suggestions for a mass 
threshold.
    Comment: A commenter said that they support the proposed provisions 
at 40 CFR 63.132(c)(1)(iii) and (d)(1)(ii) to revise the Group 1 
wastewater stream threshold to include wastewater streams in EtO 
service (i.e., wastewater streams with total annual average 
concentration of EtO greater than or equal to 1 ppmw at any flow rate). 
However, at least one commenter claimed that there is no need for the 
proposed provisions at 40 CFR 63.132(c)(1)(iii) and (d)(1)(ii) because 
the current treatment options for process wastewater streams in EtO 
service are already adequate to meet the ample margin of safety 
provided the EPA made one edit to 40 CFR 63.138(e)(1) and (2) when 
controlling streams with lower concentrations of EtO than previously 
regulated by the EPA. The commenter recommended that the EPA add an 
option to both 40 CFR 63.138(e)(1) and (2) that allows the owner or 
operator to demonstrate compliance with the performance standard for 
EtO if the outlet concentration of EtO is less than 1 ppmw on an annual 
average basis. The commenter argued that based on the EPA's proposed 
definition of ``in ethylene oxide service'' for wastewater streams it 
may be difficult to demonstrate a 98- or 99-percent mass removal 
efficiency for EtO especially if the concentration flowing into the 
treatment device is a very low concentration; for example, if the inlet 
flow is 0.1 lb/hr then it may be difficult to demonstrate that the 
outlet flow is 0.002 lb/hr (98 percent efficiency) or 0.001 lb/hr (99 
percent efficiency).
    The commenter argued that EtO should only be included on Table 9 to 
NESHAP subpart G and removed from Table 8 to NESHAP subpart G for the 
following reasons:
     The EPA provides no basis for adding EtO to Table 8 in the 
document titled Analysis of Control Options for

[[Page 42980]]

Wastewater Streams to Reduce Residual Risk of Ethylene Oxide in the 
SOCMI Source Category for Processes Subject to HON (see Docket Item No. 
EPA-HQ-OAR-2022-0730-0087).
     The original basis for the compounds listed on Table 8 was 
that this subset of compounds are very volatile compounds. All the 
compounds listed on Table 8 have a fraction removed (Fr) value \43\ 
equal to 0.99 as stated in 40 CFR 63.138(e)(2); and the Fr value for 
EtO as stated in Table 9 is equal to 0.98. Pages 4-9 to 4-10 of the HON 
Background Information Document (see EPA-453/R-94-003b) provides the 
original basis for which compounds are included on Table 8 versus Table 
9.
---------------------------------------------------------------------------

    \43\ The Fr is the fraction of a HAP that is stripped from 
wastewater and is an indicator of the extent to which a HAP is 
effectively removed during the stream-stripping process.
---------------------------------------------------------------------------

     The fraction emitted (Fe) value \44\ for the compounds 
listed on Table 8 range from 0.79 to 1. A value of 1 represents 100 
percent of the compound in the wastewater is volatized to the 
atmosphere; and EtO has a Fe value of 0.5 or only 50 percent is 
volatilized.
---------------------------------------------------------------------------

    \44\ The Fe is the mass fraction of a HAP that is emitted from 
the wastewater collection and downstream biological treatment system 
and is an indicator of the fraction of a compound expected to be an 
air emission out of wastewater in typical chemical sector collection 
and treatment systems.
---------------------------------------------------------------------------

     For new sources, 40 CFR 63.132(b)(2) already requires a 
determination as to whether each wastewater stream requires control for 
Table 9 compounds by complying with 40 CFR 63.132(c). 40 CFR 
63.132(c)(1)(iii) (as proposed) specifies that a wastewater stream is a 
Group 1 wastewater stream for Table 9 compounds if the wastewater 
stream contains EtO such that it is considered to be in EtO service.
    The commenter argued that the way the group determination 
procedures are structured, adding EtO to Table 8 (when it is already 
included as a Table 9 compound) is not going to change the fact that a 
stream containing more than 1 ppmw EtO is considered to be in EtO 
service and subject to further treatment and control regardless of 
whether the source is existing or new.
    Response: The EPA acknowledges the commenters' support for and 
opposition of the proposed wastewater provisions at 40 CFR 
63.132(c)(1)(iii) and (d)(1)(ii). We are finalizing these provisions as 
proposed. We believe the rule is clear with regard to demonstrating 
compliance with these provisions. A wastewater stream that is less than 
1 ppmw EtO is not considered a Group 1 wastewater stream, since it 
would not meet the Group 1 criteria at 40 CFR 63.132(c)(1)(iii) and 
(d)(1)(ii), provided it does not meet the criteria at 40 CFR 
63.132(c)(1)(i) and (ii), and (d)(1)(i) either.
    The EPA does not agree with the commenter that EtO should be 
removed from Table 8 to NESHAP subpart G. Simply put, the compounds in 
Table 8 do not biodegrade well and will need to be stripped, while the 
compounds in Table 9 to NESHAP subpart G can be treated using a 
biological treatment process. While we acknowledge EtO can be 
biodegraded (and is included in Table 9), its low Fe value (0.5) 
suggests that it can only be reduced by half when using a standard 
biological treatment method, and the remainder would need to be 
stripped out of the wastewater in order to meet the 1 ppmw threshold. 
Since we are building on the existing HON standards, we believe it is 
appropriate to restrict the treatment options given the risk associated 
with EtO, and have determined facilities will have to use steam 
stripping to comply with the proposed standards. For these reasons, it 
is not appropriate to add an option, as requested by the commenter, to 
both 40 CFR 63.138(e)(1) and (e)(2) that allows the owner or operator 
to demonstrate compliance with the performance standard for EtO if the 
outlet concentration of EtO is less than 1 ppmw on an annual average 
basis regardless of the control method.
    However, we agree with the commenter that verifying mass reductions 
of 99 percent for wastewater streams containing small amounts of EtO 
may be difficult. As a result, we are providing language in the final 
rule at 40 CFR 63.138(b)(3) and (c)(3) that allows owners or operators 
to reduce, by removal or destruction, the concentration of EtO to less 
than 1 ppmw as determined by the procedures specified at 40 CFR 
63.145(b). We believe these revisions add clarity that streams less 
than 1 ppmw EtO are no longer considered to be ``in ethylene oxide 
service'' per the definition and provides unity with the finalized 
addition of EtO to Table 8 to NESHAP subpart G.
    Comment: A commenter recommended that the EPA incorporate the test 
methods specified in 40 CFR 63.109(d) for analysis of EtO in wastewater 
directly into 40 CFR 63.144(b)(5)(i) to provide consistency and clarity 
with the regulation and to avoid the need to prepare additional 
sampling plans and method validation under 40 CFR 63.144(b)(5)(ii) and 
(iii). The commenter argued that in order to use the test methods 
specified in 40 CFR 63.109(d) for determining the annual average 
concentration of EtO in the wastewater streams (i.e., EPA Method 624.1 
of 40 CFR part 136, appendix A, or preparation by either EPA Method 
5031 or EPA Method 5030B and analysis by EPA Method 8260D in the SW-846 
Compendium), without the additional cost and effort required to prepare 
sampling plans and validate the test methods per 40 CFR 
63.144(b)(5)(ii) and (iii), these methods listed in 40 CFR 63.109(d) 
for EtO need to either be added to the list of acceptable methods under 
40 CFR 63.144(b)(5)(i) or a cross-reference to 40 CFR 63.109(d) needs 
to be added to 40 CFR 63.144(b)(5)(i).
    In addition, the commenter claimed that depending upon what 
treatment option is selected in 40 CFR 63.138 to meet the requirements 
for wastewater streams in EtO service, the test methods and procedures 
in 40 CFR 63.145(b) for determining compliance with concentration limit 
standards for non-combustion treatment processes in 40 CFR 63.138(b)(1) 
and (c)(1) cross-reference the methods specified in 40 CFR 
63.144(b)(5)(i). The commenter asserted that by adding the methods 
specified in 40 CFR 63.109(d) for determining the EtO concentration to 
the list of acceptable test methods in 40 CFR 63.144(b)(5)(i), the EPA 
would be also fixing other cross-referencing issues in 40 CFR 63.145 at 
the same time.
    Response: We are revising the final rule in response to the 
commenter's request to add the test methods specified in 40 CFR 
63.109(d) for analysis of EtO in wastewater to 40 CFR 63.144(b)(5)(i). 
We agree that these test methods are relevant to calculate the annual 
average concentration of EtO needed to determine Group status, and, by 
including them, we should create consistency between 40 CFR 63.109(d), 
40 CFR 63.144(b)(5)(i), and 40 CFR 63.145.
    Comment: A commenter said that they support the proposed provisions 
at 40 CFR 63.104(k) to prohibit owners and operators from injecting 
wastewater into or disposing of water through any heat exchange system 
in a CMPU meeting the conditions of 40 CFR 63.100(b)(1) through (3) if 
the water contains any amount of EtO, has been in contact with any 
process stream containing EtO, or the water is considered wastewater as 
defined in 40 CFR 63.101. On the contrary, other commenters provided 
suggestions for this prohibition. At least one of these commenters 
contended that the EPA has not identified any risk associated with EtO-
free wastewaters, nor has the EPA otherwise justified why EtO-free 
wastewaters are prohibited from injection. This commenter said they 
generally support not allowing

[[Page 42981]]

waters containing EtO or chloroprene to be added to the cooling loop of 
a heat exchange system. However, the commenter noted that in the case 
of the HON and P&R I rules, a wastewater is ``water that is discarded'' 
from a CMPU or an EPPU, respectively; therefore, wastewater that is 
injected into a cooling loop is not discarded water.
    Commenters argued the proposed language prohibiting the use of 
``wastewater'' in heat exchange systems is a significant barrier to, if 
not total prohibition on, water reuse projects that are under 
consideration at various member facilities. The commenter requested 
that the EPA modify the prohibition on using ``wastewater'' in heat 
exchange systems to make clear that stormwater collected in process 
areas and treated wastewater from process areas that may include EtO 
but still qualify for discharge in accordance with a national pollutant 
discharge elimination system (NPDES) permit may be used in heat 
exchange systems.
    A commenter said that the EPA should add the requirements into the 
process wastewater prohibition language that already exists in 40 CFR 
63.132(f) (rather than include new provisions at 40 CFR 63.104(k)). The 
commenter claimed that the intent of the prohibition language in 40 CFR 
63.132(f) is to prevent discarding a liquid or solid material 
containing greater than 10,000 ppmw of a Table 9 (to NESHAP subpart G) 
HAP to water or wastewater unless it is controlled as a Group 1 
wastewater; and as currently proposed, a liquid or solid material that 
is in EtO service, could be discarded to a wastewater stream without 
control. The commenter urged the EPA to add the following sentence to 
the beginning of 40 CFR 63.132(f): ``Owners or operators of each source 
as defined in Sec.  63.101, beginning no later than the compliance 
dates specified in Sec.  63.100(k)(11), shall not discard liquid or 
solid stream containing EtO such that it is considered to be in EtO 
service, as defined in Sec.  63.101 from a chemical manufacturing 
process unit to water or wastewater, unless the receiving stream is 
managed and treated as a Group 1 wastewater stream.'' Alternatively, 
the commenter suggested the EPA could revise the proposed rule text in 
40 CFR 63.104(k) in lieu of adding their request sentence to the 
beginning of 40 CFR 63.132(f).
    Response: The EPA acknowledges the commenters' support for and 
opposition to the proposed provisions that prohibit the injection or 
disposal of wastewater containing or that has come in contact with EtO, 
through heat exchange systems. We are finalizing these provisions at 40 
CFR 63.104(k) as proposed. We disagree with commenters' requests to 
allow stormwater or treated wastewater that may contain EtO but qualify 
for discharge under the NPDES. We note that in a 1980 document titled 
Water Quality Requirements of the Organic Chemicals Industry for 
Recycle/Reuse Applications, which is available in the docket for this 
rulemaking, the potential for increased recycle/reuse for process water 
in the EtO industry was evaluated. It was found that significant 
evaporation losses occur from process cooling towers. Any amount of EtO 
in wastewater sent to cooling towers will inevitably be stripped out 
and lead to a direct emission event. This is further expanded upon in 
the preamble to the proposed rule (see 88 FR 25080, April 25, 2023), 
where we cite emissions events from two HON-subject facilities that 
reported EtO emissions from heat exchange systems. This was due to 
combining EtO entrained water with heat exchange water and not due to 
any heat exchange system leaks, and resulted in ~3 tpy of EtO total 
emitted. Given the current total risk associated with EtO, allowing any 
EtO in cooling towers would be unacceptable.
v. EtO Flare Load Limit
    Comment: A commenter said that they support the proposed 
requirement at 40 CFR 63.108(p) that prohibits owners and operators 
from sending more than 20 tons of EtO to all of their flares combined 
in any consecutive 12-month period. Other commenters asserted that the 
EPA must strengthen the monitoring needed to ensure compliance with the 
EtO flare load limit proposed at 40 CFR 63.108(p). The commenters 
stated that the requirement that ``the owner or operator must keep 
monthly records of the quantity in tons of ethylene oxide sent to each 
flare at the affected source and include a description of the method 
used to estimate this quantity'' is left completely up to HON sources 
to determine how to calculate the amount of EtO sent to their flares. 
The commenters contended that this cannot ensure compliance with the 
EtO flare load limit, and thus, cannot ensure that risk is reduced to 
an acceptable level or that the standards provide an ample margin of 
safety to protect public health. The commenters asserted that this 
monitoring requirement is arbitrary and capricious and contrary to CAA 
sections 112(f) and 114(a)(3). The commenters suggested that the EPA 
require HON sources to calculate the amount of EtO sent to their flares 
by: (i) Continuously measuring the flow rate of the waste gas to the 
flare using a continuous emission monitoring system; (ii) continuously 
measuring the EtO concentration in the waste gas, also by a continuous 
emission monitoring system; and (iii) using the data from (i) and (ii) 
to calculate the actual EtO mass that is sent to the flare over a given 
time period. The commenters added that this calculation can be done 
every minute if needed or on an hourly average basis, to provide an 
accurate mass estimate of the flared EtO.
    Numerous other commenters opposed the EtO flare load limit for at 
least one or more of the following reasons:
     it is unwarranted to impose expensive and stringent EtO 
limitations on flaring on the entire SOCMI source category subject to 
the HON when unacceptable risk from EtO flaring is driven by a single 
facility.
     the proposed cap would be problematic for more than just 
the flares that the EPA identified given that many owners and operators 
are currently applying a 99 percent EtO control efficiency to their 
existing flare operations.\45\ TCEQ's control efficiency value for EtO 
(99 percent) combined with the EPA's determination that EtO emissions 
of 0.4 tpy would be acceptable (see Docket Item No. EPA-HQ-OAR-2022-
0730-0070) would yield a 40 tpy (not 20 tpy) EtO flare load limit.
---------------------------------------------------------------------------

    \45\ The commenters cited TCEQ's ``New Source Review (NSR) 
Emission Calculation'' guidance (available at: https://www.tceq.texas.gov/assets/public/permitting/air/Guidance/NewSourceReview/emiss_calc_flares.pdf) and said that Texas allows 
owners and operators to apply a 99 percent destruction efficiency 
for flaring compounds containing no more than 3 carbons that contain 
no elements other than carbon and hydrogen in additional to a select 
number of compounds, including EtO.
---------------------------------------------------------------------------

     when conducting its dispersion modeling for EtO emissions 
from flares, the EPA did not use the modeling approach used by TCEQ 
which takes into account the heat release associated with combustion in 
a flare; TCEQ's modeling approach results in lower off-site impacts 
from flares, which calls into question whether a cap of flaring is 
necessary.
     flares have been used to control emissions of HAP for 
decades.
     the combination of the proposed 20 tpy flare cap along 
with the removal of the delay of repair provisions and the proposed PRD 
provisions may have unintended consequences leaving owners and 
operators with very few options for compliance if additional shutdowns 
and start-ups are needed to address a leaking component and/or if a PRD 
discharge to a flare occurs.

[[Page 42982]]

     the EPA's proposed solution to replace flares with thermal 
oxidizers is not practical from a timing or cost perspective.
     thermal oxidizers are generally not suitable destruction 
devices for PRD effluents; therefore, plants would need a new thermal 
oxidizer along with a flare operating for unplanned discharges like PRD 
vents, and the EPA's cost estimates are not reflective of the actual 
costs that would incur in the 2023-2026 timeframe to install a new 
thermal oxidizer system. It is common practice to size a thermal 
oxidizer for a normal range of VOC concentrations and normal flow and 
have an emergency flare to accommodate a higher concentration and flow 
from an event. Using a thermal oxidizer in lieu of a flare to manage 
EtO emissions would necessitate designing the oxidizer to accommodate 
these larger intermittent flows and higher inlet concentrations of VOC; 
however, such a design might not be feasible because normal operation 
might represent too much of a ``turndown'' from emergency operation.
     lead/delivery time for a new thermal oxidizer system could 
exceed 52 weeks, but 12 months is a best estimate.
     replacing flares with a thermal oxidizer essentially 
maintains greenhouse gas emissions at the same level since EtO is 
combusted in both applications.
     there may be safety and reliability considerations not 
addressed by the EPA with the use of a thermal oxidizer, which would 
require design and process safety features due to the reactive and 
flammable nature of EtO.
    Commenters said that instead of replacing flares with thermal 
oxidizers to meet the EPA's proposed EtO flare load limit, owners and 
operators could potentially add a water scrubber between vent sources 
like storage vessels and railcar loading/unloading operations and the 
existing flares; however, this option would likely still need a larger 
EtO flare load limit than the 20 tpy limit the EPA has proposed. The 
commenters said that water from the scrubber could then be routed to 
the EtO manufacturing processes at these sites where the EtO could be 
recovered as a product stream. However, the commenters pointed out that 
during times when the EtO manufacturing process unit is not in service, 
the internal scrubber systems would need to be turned off as there is 
no viable location to recover the EtO out of the scrubber water stream. 
Thus, during times when storage vessels and railcar loading/unloading 
operations would need to occur but the production plant is not in 
service, the vent gas from the tank vents and loading/unloading 
operations would need to be routed to the existing logistics flares. In 
other words, the commenters contended that the amount of EtO that would 
be routed to these flares in the future is a function of the operating 
time of the production plant.
    In summary, commenters said they are concerned that projects that 
would be needed in order to meet the 20 tpy EtO flare load limit could 
not be implemented within 2 years as proposed in 40 CFR 63.100(k)(11), 
nor would the EPA's proposed control option achieve the intended 
reductions and may actually result in an increase in secondary 
emissions. Thus, these commenters requested that the EPA either refrain 
from finalizing the proposed flare cap or increase the flare cap based 
on a 99 percent control efficiency and provide 3 years for facilities 
to comply with the revision.
    Response: We are not finalizing the requirement at 40 CFR 63.108(p) 
that prohibits owners and operators from sending more than 20 tons of 
EtO to all of their flares combined in any consecutive 12-month period. 
In other words, we are not including an EtO flare load limit in the 
final rule. In response to a comment discussed in section 1.1 of the 
document titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking, we have determined that it is appropriate to use a 
different modeling approach for the final rule than the approach we 
used for the proposed rule (i.e., we used the TCEQ modeling guidelines 
to calculate effective flare stack parameters for the final rule in 
lieu of modeling all flare releases as standard point sources with 
temperatures less than 1,000 Kelvin and velocities less than one meter 
per second for the proposed rule). As explained in that response, 
modeling flare emissions using effective stack parameters accounts for 
heat release of the flare and better characterizes plume rise. After 
applying this approach for the final rule, we have determined the EtO 
flare load limit is no longer necessary as flares controlling EtO are 
no longer significant contributors to risk. Using the reported EtO 
emissions of 2.87 tpy (post-control) from the highest-emitting 
facility, we estimate that the facility's current combined total EtO 
load to flares is about 143.5 tpy (pre-control). Based on the revised 
modeling, a flare controlling 143.5 tpy (far higher than the proposed 
20 tpy flare cap) is not a significant risk driver. Using the TCEQ 
modeling guidelines for flares, we have determined that risk for the 
SOCMI source category remains below 100-in-1 million without the need 
of an EtO flare load limit, but only after implementation of the 
standards we are finalizing for: (1) Process vents, (2) storage 
vessels, (3) equipment leaks, (4) heat exchange systems, and (5) 
wastewater ``in ethylene oxide service,'' as well as implementation of 
the final requirements to reduce EtO emissions from maintenance vents 
and PRDs. We note that by not finalizing an EtO flare load limit we 
also obviate the inconsistency we unintentionally created in the 
proposed rule by requiring owners and operators to comply with an EtO 
flare load limit while also requiring owners and operators to minimize 
emissions from PRDs by routing them to flares instead of venting to the 
atmosphere.
vi. PRDs in EtO Service
    Comment: Commenters argued that the requirement at 40 CFR 
63.165(e)(3)(v)(D) that considers any atmospheric release from a PRD in 
EtO service a violation will not reduce risk given that PRD releases 
are non-routine events that take place to prevent catastrophic 
equipment failure. The commenters contended that deeming atmospheric 
PRD releases a violation will not reduce their occurrence. The 
commenters stated that the proposed work practice standards at 40 CFR 
63.165(e) (including the deviation determination criteria at 40 CFR 
63.165(e)(3)(v)(A) through (C)) already provide an effective framework 
for addressing PRD releases.
    The commenters added it is not cost-effective to route all PRDs to 
control devices; and the EPA wrongly assumes that all releases from 
PRDs in EtO service can and will be controlled as process vents as a 
result of the prohibition on such releases. The commenters provided 
numerous examples of why certain PRDs cannot be safely routed to a 
control device and/or would be technically infeasible in many process 
designs such as hydraulic limitations of flare systems or other 
controls, PRD backpressure, EtO incompatibility with other collected 
compounds, and polymerization of ethylene in closed vent systems. 
Commenters argued that because PRD releases are usually non-routine, 
infrequent, and episodic, piping and the control device would have to 
be sized

[[Page 42983]]

to accommodate significantly larger flow than normal process vents, and 
the control device would be required to operate in an indefinite 
``stand-by'' mode to accommodate unexpected and emergency releases. A 
commenter said ``stand-by'' mode may also require significant amounts 
of fuel and generate secondary combustion emissions on a continuous 
basis for a release that may or may not occur.
    Response: We are finalizing these requirements for PRDs in EtO 
service pursuant to CAA section 112(f)(2), on the basis of risks being 
unacceptable. Where we find risks are unacceptable, the EPA must 
determine the emissions standards necessary to reduce risk to an 
acceptable level. Because emissions of EtO from the SOCMI source 
category result in unacceptable risks, we proposed and are finalizing 
requirements that would reduce risks to an acceptable level, including 
provisions that would make all PRD releases of EtO directly to the 
atmosphere a violation of the standard. As explained in response to a 
comment in section 1.1 of the document titled Summary of Public 
Comments and Responses for New Source Performance Standards for the 
Synthetic Organic Chemical Manufacturing Industry and National Emission 
Standards for Hazardous Air Pollutants for the Synthetic Organic 
Chemical Manufacturing Industry and Group I & II Polymers and Resins 
Industry, which is available in the docket for this rulemaking, the EPA 
modeled certain PRD releases of EtO during maintenance events which 
resulted in very high risk from one facility (i.e., EtO risk from 
process vent emission sources emitted through PRDs is approximately 75 
percent of the Port Neches facility's total SOCMI source category risk 
of 2000-in-1 million). There is no reason for not considering the 
impact of these events in our risk modeling and rulemaking. In 
response, we proposed and are finalizing a requirement that releases 
from PRDs in EtO service are a violation of the emission standard.
vii. Other EtO Related Requirements
    Comment: Commenters asserted that the EPA acted unreasonably in 
imposing controls across the entire ``HON source category.'' The 
commenters contended that the EPA may require those facilities that 
pose unacceptable risk to implement targeted additional controls, but 
it is arbitrary and capricious to attempt to impose those same 
requirements everywhere despite the absence of risk. A commenter 
provided an example where under the proposed rule, both Huntsman Conroe 
and Huntsman Geismar facilities would be heavily burdened by the 
proposed HON EtO control requirements even though the EPA found that 
neither facility poses unacceptable risk.
    These commenters said that the EPA's proposed response to 8 
facilities with EtO risk above the presumptive limit is a one-size-
fits-all approach to addressing risk from the source category that 
unreasonably imposes stringent control requirements across all 
emissions sources at every facility, rather than addressing the 
residual risks that were actually identified. The commenters said the 
approach is inconsistent with CAA section 112(f) because half of the 
facilities affected by the proposed EtO standards do not present 
unacceptable risk to surrounding areas, yet the EPA proposes to impose 
emissions standards on these facilities that were derived without 
consideration of cost. A commenter pointed out that Congress explicitly 
granted the EPA the authority to consider variations among sources in 
promulgating emission standards under CAA section 112 through 
subcategorization; yet, the EPA has failed to utilize this statutorily 
available tool here. Commenters said that even if the Agency chooses 
not to subcategorize, the EPA has recognized that it is unreasonable to 
require controls on all facilities when a more targeted and less costly 
option may achieve an acceptable level of risk. The commenters pointed 
out that the EPA used a tailored approach in the RTR for sterilization 
facilities (see 88 FR 22790, 22826-28) and the proposed MON rule (see 
84 FR 69182) which applied different levels of stringency in accordance 
with the different facilities' MIRs (in other words, the EPA tailored 
its acceptability analysis to address risk from the highest risk 
sources).
    A commenter added that the EPA's approach is not sufficiently 
targeted because the applicability of the new EtO emissions standards 
would be governed by the definition of ``in ethylene oxide service'' 
that the EPA adopted in the MON, which was not derived with any 
consideration of the emissions characteristics of the SOCMI source 
category or the risk profile determined by the EPA's risk assessment of 
the SOCMI source category. The commenter contended that adopting the 
MON definition of ``in ethylene oxide service'' results in new EtO 
emissions standards that apply to approximately twice as many affected 
facilities as needed to address the risk that the EPA determines to be 
actionable.
    Response: We disagree with the commenters that the EPA acted 
unreasonably in imposing controls across the entire SOCMI source 
category (note the commenter used the phrase ``HON source category;'' 
however, the source category covered by the HON is actually the SOCMI 
source category). We also disagree with the commenters that our action 
to impose the same EtO requirements on each owner and operator is 
arbitrary and capricious.
    As stated in the preamble to the proposed rule (see 88 FR 25080, 
April 25, 2023), we identified EtO as the cancer risk driver from HON 
sources; and we are aware of 15 HON facilities reporting more than 0.1 
tpy of EtO emissions in their emissions inventories from HON processes 
and two other facilities that are new or under construction with HON 
processes that we expect will exceed this threshold (but for which we 
do not yet have emissions inventory information). Of these 17 
facilities, 12 facilities produce and emit EtO, which is a process 
subject to the HON MACT standards. In addition, all 17 of these 
facilities have additional HON processes that use and emit EtO in the 
production of glycols, glycol ethers, or ethanolamines. Therefore, we 
are not imposing EtO controls across the entire SOCMI source category. 
Rather, in order to reduce emissions of EtO from HON processes, the EPA 
is finalizing more stringent control requirements for process vents, 
storage vessels, equipment leaks, heat exchange systems, wastewater, 
maintenance vents, and PRDs that emit or have the potential to emit 
EtO. While it is true from our residual risk assessment that eight of 
the 17 facilities with emissions of EtO from various HON processes have 
cancer risks above 100-in-1 million, the standards are national 
standards that apply to specific types of sources rather than specific 
facilities, and the revisions ensure that risks from the source 
category are acceptable and that the standards provide an ample margin 
of safety to protect public health. As such, we disagree with the 
commenter that we should target additional controls on only facilities 
that pose unacceptable risk.
    For these same reasons, we also disagree with the commenter that 
adopting the MON definition of ``in ethylene oxide service'' results in 
new EtO emissions standards that apply to approximately twice as many 
affected facilities as needed to address the risk that the EPA 
determines to be actionable. Although, as noted in our proposal, 
similar emission sources and standards exist between the HON and MON, 
we disagree with the commenter that we did not give any consideration

[[Page 42984]]

of the emissions characteristics of the SOCMI source category or the 
risk profile determined by the EPA's risk assessment of the SOCMI 
source category. The scientific and technical bases for the EPA's 
proposed action are voluminously presented in the numerous supporting 
memoranda contained in the public docket for the proposed rulemaking. 
See, e.g., the documents titled Residual Risk Assessment for the SOCMI 
Source Category in Support of the 2023 Risk and Technology Review 
Proposed Rule; Analysis of Control Options for Process Vents and 
Storage Vessels to Reduce Residual Risk of Ethylene Oxide in the SOCMI 
Source Category for Processes Subject to HON; Analysis of Control 
Options for Equipment Leaks to Reduce Residual Risk of Ethylene Oxide 
in the SOCMI Source Category for Processes Subject to HON; Analysis of 
Control Options for Heat Exchange Systems to Reduce Residual Risk of 
Ethylene Oxide in the SOCMI Source Category for Processes Subject to 
HON; Analysis of Control Options for Wastewater Streams to Reduce 
Residual Risk of Ethylene Oxide in the SOCMI Source Category for 
Processes Subject to HON; (see Docket Item No. EPA-HQ-OAR-2022-0730-
0085, -0074, -0003, -0071, and -0087, respectively).
e. P&R I NESHAP Rule Changes Related to Chloroprene
i. Process Vents and Storage Vessels in Chloroprene Service
    Comment: A commenter argued that the EPA's proposal at 40 CFR 
63.484(u), 40 CFR 63.485(y), and 40 CFR 63.487(j) to require a control 
device that reduces chloroprene by greater than or equal to 99.9 
percent by weight is unreasonable in light of the EPA's involvement in 
the decision to install a regenerative thermal oxidizer (RTO) at one 
facility with a chloroprene destruction efficiency of 98 percent and 
the ``monomer emission reduction project'' (MERP) system \46\ with a 
chloroprene destruction efficiency of 99.3 percent. The commenter made 
the following points regarding these installations:
---------------------------------------------------------------------------

    \46\ The commenter stated that the MERP was installed to route 
vent emissions from the monomer process unit to the facility's 
halogen acid production furnace. The MERP is essentially a complex 
of vent headers (with condensate collection posts) to route 
emissions predominately from the Monomer area of the Neoprene 
Facility, as well as emissions from nine permitted hazardous waste 
tanks (containing liquid hazardous wastes) to the facility's halogen 
acid production furnace. The MERP conveys approximately 300 to 600 
CFM of chloroprene vent emissions from currently ``Group 2'' 
classified emission units under the HON subpart G. Stack tests have 
demonstrated a 99.3 percent destruction or removal efficiency for 
the halogen acid production furnace.
---------------------------------------------------------------------------

    During the first six months of 2016, the facility engaged in 
numerous meetings with both the EPA and the LDEQ to discuss options for 
reducing chloroprene emissions, including different types of control 
devices. Records of these discussions show that, in October 2016, the 
facility presented slides to the EPA and the LDEQ that summarized 
control device options, including a direct-fired thermal oxidizer (the 
only option that could achieve a chloroprene destruction efficiency of 
99.9 percent) and an RTO, which was expected to have a chloroprene 
destruction efficiency of 98 percent. As the slide indicated, however, 
the cost of operating a direct-fired thermal oxidizer would be very 
high because it would burn enormous amounts of natural gas. This is why 
in June 2016, the facility proposed to install an RTO, which would have 
similar up-front capital costs but would have much lower operating 
costs (and much lower CO2 emissions) because it would 
require much less natural gas to operate.
    In December 2016, the LDEQ held a large public meeting at its 
headquarters, with the EPA and the Department of Justice in attendance. 
Before this meeting, an EPA researcher advised EPA officials that, to 
achieve a risk-level of 1-in-10,000, ambient concentrations of 
chloroprene in the community could be no higher than 0.2 ug/m\3\. His 
memorandum making this assertion was also released publicly. At this 
meeting, the facility presented results of an air dispersion modeling 
study, which showed then-existing (2016) ambient concentrations and the 
concentrations that would be expected if the facility implemented the 
emission reduction projects it had proposed, including the installation 
of an RTO with a chloroprene destruction efficiency of 98 percent. The 
modeling results presented to the EPA, the LDEQ, and the public showed 
that offsite concentrations would be significantly reduced but would 
still be higher than 0.2 ug/m\3\.
    Following the public hearing, the facility, the EPA, and the LDEQ 
finalized the terms of a voluntary Administrative Order on Consent, 
which the facility and the LDEQ signed on January 6, 2017. The EPA and 
lawyers from the Department of Justice were present for all significant 
discussions, and the EPA was heavily involved in the Administrative 
Order on Consent's development, providing numerous comments and making 
a number of demands reflected in the order. Under the Administrative 
Order on Consent, the facility agreed to ``install and operate . . . a 
Regenerative Thermal Oxidizer (RTO)'' capable of ``achiev[ing] at least 
a 98 percent [destruction or removal efficiency].'' The facility also 
agreed to install the MERP and to achieve an 85 percent reduction in 
total chloroprene emissions from the facility, principally from the 
``Chloroprene'' Unit, to the facility's halogen acid production 
furnace.
    The commenter claimed that these projects reduced facility 
chloroprene emissions by 85 percent at a capital cost of $35 million, 
plus a significant increase in annual operating costs; and of the $35 
million, the MERP cost approximately $9 million. The commenter 
requested that the EPA take this history into account as it develops 
the final rule given that it is unreasonable to ignore the investments 
that the facility recently made to reduce chloroprene emissions when 
they were made under the oversight of the LDEQ and the EPA, and with 
the EPA's full knowledge of the 2010 IRIS inhalation URE value for 
chloroprene. The commenter contended that the very small emission 
reductions that would be achieved by increasing the chloroprene 
destruction efficiency to 99.9 percent are enormously expensive, more 
than $21 million per ton annually. The commenter said the current 
chloroprene emissions from the existing RTO are approximately 0.84 tpy; 
therefore, if all the emission streams currently routed to the existing 
RTO were instead routed to a new direct-fired thermal oxidizer with a 
chloroprene destruction efficiency to 99.9 percent, chloroprene 
emissions would be reduced from 0.84 tpy to 0.04 tpy (an annual 
reduction of 0.79 tons). The commenter claimed that the annualized cost 
of achieving this is almost $3.7 million, and the cost-per-ton of 
chloroprene emission reduction would be more than $4.6 million. The 
commenter submitted a similar analysis for their MERP system and 
claimed that if all the vent streams currently controlled by the MERP 
were instead routed to a control device with a chloroprene destruction 
efficiency of 99.9 percent (testing has demonstrated that the MERP 
achieves a destruction or removal efficiency of 99.3 percent on an 
overall basis), the reduction in annual chloroprene emissions would be 
50-60 pounds, depending on production.
    The commenter said that they hired consultants to evaluate multiple 
options for control device configuration that would achieve a 
chloroprene destruction efficiency of 99.9 percent as required by the 
proposed rule. The commenter said that modifying their existing RTO to 
achieve a chloroprene destruction efficiency of 99.9 percent is

[[Page 42985]]

not possible given that high levels of chlorine in their exhaust 
streams would poison the catalyst. The commenter added that even if 
their existing RTO could achieve a chloroprene destruction efficiency 
of 99.9 percent, it does not have capacity to accommodate the 
additional streams that would have to be routed to it under the 
proposed rule; thus, the proposed rule would require the installation 
of one or more new control devices that could accommodate very high air 
flows containing very low concentrations of VOC, including chloroprene. 
The commenter provided specific details of other control options and 
acknowledged that the destruction efficiency of an RTO can be increased 
to 99.9 percent by adding an additional oxidation step (which involves 
the installation of a polishing catalyst bed in the stack that reheats 
the treated gas); however, the commenter asserted that all other 
options that they evaluated (e.g., installing new RTOs and/or direct 
fired thermal oxidizers) would require enormous amounts of fuel 
consumption, quench water, and power consumption only to achieve 
minimum reductions.
    The commenter asserted that the EPA's cost estimate to install a 
new direct fired thermal oxidizer is ``far from realistic'' given that 
their consultant estimated the equipment purchase costs for a new 
direct fired thermal oxidizer with recuperative heat exchange 
capabilities would be approximately $12 million and total annual costs 
of $39 million. The commenter said the EPA assumed a slightly smaller 
direct fired thermal oxidizer than what they believe would be necessary 
and the EPA estimated an equipment purchase cost of $5 million and 
total annual costs of $10.1 million; however, the commenter asserted 
that it is not clear if the EPA's estimate includes the additional 
scrubber capacity or the high nickel alloy materials that would be 
needed for certain components. The commenter added that the EPA has not 
estimated the costs that would be required to upgrade the electrical 
and natural gas infrastructure, or expand the wastewater treatment 
plant (WWTP), which are all actions that would be necessary to install 
a new direct fired thermal oxidizer.
    In summary, the commenter claimed that given that it is not 
possible to modify their existing RTO and MERP to achieve a chloroprene 
destruction efficiency of 99.9 percent, the proposed rule would leave 
the facility with $35 million of stranded investment which was made 
fewer than 6 years ago to reduce chloroprene emissions in consultation 
with the EPA. The commenter said that even though the option of 
installing a direct-fired thermal oxidizer was discussed in 2016, at no 
point did the EPA suggest that an RTO would not be sufficient or that a 
direct-fired thermal oxidizer might be required. The commenter asserted 
that there has been no change since 2016 in either (1) the EPA's views 
about the risk of chloroprene exposure or (2) its understanding of the 
offsite concentrations that would be achieved under the Administrative 
Order on Consent.
    Response: We reevaluated whether we could change the proposed 99.9 
percent by weight reduction standard to 98 percent by weight given the 
commenter's arguments that their existing RTO and MERP cannot achieve a 
chloroprene reduction of 99.9 percent by weight. In our reevaluation 
for the final rule, we determined that revising the performance 
standard for process vents and storage vessels in chloroprene service 
(from a 99.9 percent by weight reduction requirement as proposed to a 
98 percent by weight reduction requirement in the final rule) will 
still maintain the MIR at 100-in-1 million for the Neoprene Production 
source category and thereby result in the source category chloroprene 
emissions being reduced to acceptable levels. We have made this change 
in the final rule at 40 CFR 63.484(u)(1), 40 CFR 63.485(y)(1), 40 CFR 
63.487(j)(1), and 40 CFR 63.510(a)(2). While considering the current 
chloroprene emissions from both the existing RTO (0.84 tpy) and MERP 
(0.02 tpy based on our review of the emissions inventory calculations), 
we have determined the revised performance requirements for the final 
rule will still reduce risk from Neoprene Production source category 
emissions to an acceptable level and also provide an ample margin of 
safety to protect public health (as was proposed) for the Neoprene 
Production source category. We also have determined that no additional 
requirements are needed to prevent an adverse environmental effect (as 
was proposed). In light of this, we believe the commenter's existing 
RTO and MERP can be used to meet the revised requirements for the final 
rule and would no longer be considered a stranded investment as the 
commenter has claimed.
    Comment: A commenter said they support the EPA's proposed rule text 
at 40 CFR 63.485(y) that requires owners and operators to reduce 
emissions of chloroprene from continuous front-end process vents in 
chloroprene service at affected sources producing neoprene by venting 
emissions through a closed-vent system to a non-flare control device 
that reduces chloroprene by greater than or equal to 99.9 percent by 
weight, to a concentration less than 1 ppmv for each process vent, or 
to less than 5 lb/yr for all combined process vents. The commenter said 
they also support the EPA's proposed rule text at 40 CFR 63.487(j) to 
add these same chloroprene standards for batch front-end process vents 
at affected sources producing neoprene. However, another commenter 
argued that the EPA's oversimplification of the design configurations 
necessary to comply with these proposed performance standards (which 
the EPA presented in Docket Item No. EPA-HQ-OAR-2022-0730-0083) results 
in cost estimates that are much too low. The commenter asserted the EPA 
did not consider in their analysis the following technical and process 
safety challenges:
     The EPA assumed that all the sources at this commenter's 
facility are to be enclosed and routed to a new direct fired thermal 
oxidizer are in close proximity to each other, but the wash belts are 
actually located in the Finishing building, which is separate from the 
Poly building.
     The EPA did not account for complicated duct and piping 
(e.g., unique pipe lengths, diameters, number of bends), which also 
impacts pump specifications and other equipment such as the blower.
     The existing thermal oxidizer cannot accommodate the 
additional vent streams from the wash belts (at current flow rates). 
Each wash belt vent hood operates at approximately 28,000 standard 
cubic feet per minute (scfm), and total chloroprene emissions for both 
wash belt vents combined is approximately 3.3 tpy (2022 reported 
value).
     Installing an enclosure around the wash belts creates 
safety concerns given that the wash belt blower motors are equipped 
with variable frequency drives which can change air flow through the 
vent hoods; the potential variability in air flows would need to be 
evaluated by an industrial hygienist to ensure compliance with 
personnel exposure requirements, or to make recommendations for 
additional protective equipment.
     Wash belts require frequent, manual intervention from area 
personnel to ensure stable operation; workers must have physical access 
to the wash belt area to perform routine maintenance and repairs.
     Wash belt enclosures would need to be transparent to allow 
visual inspection of the process without entry and would also need to 
be durable enough to withstand frequent disassembly and reassembly.

[[Page 42986]]

     Any changes in airflows or pressures, such as those that 
will occur when installing enclosures and adjusting blower speeds (for 
the wash belts), will need to be evaluated to ensure that product 
quality standards are achievable and to ensure that production rates 
are not negatively impacted. The finishing process is designed to 
supply very precise air flows and pressure differentials throughout in 
order to maintain adhesion of the web (Neoprene product film) to the 
girt (flexible sheeting that guides the web through the process).
    The commenter submitted a cost estimate of $3.6 million for the 
purchase of a direct fired thermal oxidizer with a chloroprene 
destruction efficiency of 99.9 percent that would be sized to 
accommodate waste gas from the wash belts. The commenter estimated the 
total cost for installing and operating the thermal oxidizer would be 
about $18 million. The commenter asserted that because of the low VOC 
content in the exhaust stream, natural gas consumption would be high, 
and the total annualized costs would be almost $3.0 million (not 
including the capital costs for the enclosure and associated 
infrastructure). The commenter stated that the cost-per-ton of 
chloroprene emission reduction would be approximately $0.9 million 
(based on the 3.3 tpy of chloroprene emissions reported in their 2022 
inventory). The commenter added that operating the new thermal oxidizer 
would contribute to environmental harm including 16,200 metric tons a 
year of carbon dioxide equivalents (CO2e).
    Response: We acknowledge commenters' support and opposition for the 
provision at 40 CFR 63.485(y) that requires owners and operators to 
reduce emissions of chloroprene from continuous front-end process vents 
in chloroprene service at affected sources producing neoprene by 
venting emissions through a closed-vent system to a non-flare control 
device that reduces chloroprene by greater than or equal to 99 percent 
by weight, to a concentration less than 1 ppmv for each process vent, 
or to less than 5 lb/yr for all combined process vents. We also 
acknowledge commenters' support and opposition for the provision at 40 
CFR 63.487(j) to add these same chloroprene standards for batch front-
end process vents at affected sources producing neoprene.
    As discussed in the preamble to the proposed rule (see 88 FR 25080, 
April 25, 2023), we had determined that the only viable way to meet 
these proposed standards is to enclose all of the polymer batch 
reactors, emulsion storage vessels, strainers, and wash belt dryers and 
route the vapors to a thermal oxidizer (and thereby reduce chloroprene 
emissions from these sources, which are fugitive in nature); and the 
result of this control option would reduce chloroprene emissions from 
the polymer building, unstripped resin emulsion storage vessels, and 
wash belt dryers by 11.3 tpy (from 12 tpy to 0.7 tpy). Although we 
continue to stand by our analysis that chloroprene emissions from these 
emission sources must be reduced to decrease risk posed by emissions 
from neoprene production processes to an acceptable level, we 
reevaluated whether we could change the 99.9 percent by weight 
reduction standard to 98 percent by weight given a commenter's 
arguments (as discussed in section 3.1 of the document titled Summary 
of Public Comments and Responses for New Source Performance Standards 
for the Synthetic Organic Chemical Manufacturing Industry and National 
Emission Standards for Hazardous Air Pollutants for the Synthetic 
Organic Chemical Manufacturing Industry and Group I & II Polymers and 
Resins Industry, which is available in the docket for this rulemaking) 
that their existing thermal oxidizer cannot achieve a chloroprene 
reduction of 99.9 percent by weight. In our reevaluation for the final 
rule, we determined that revising the performance standard for process 
vents and storage vessels in chloroprene service (from a 99.9 percent 
by weight reduction requirement as proposed to a 98 percent by weight 
reduction requirement in the final rule) will still maintain the MIR at 
100-in-1 million for the Neoprene Production source category. The 
result of this revision in the final rule will reduce chloroprene 
emissions from the polymer building, unstripped resin emulsion storage 
vessels, and the wash belt dryers from 12 tpy to 0.9 tpy (i.e., a 
reduction of 11.1 tpy chloroprene in lieu of 11.3 tpy as proposed). We 
have determined these revised performance requirements for the final 
rule will still reduce risk to an acceptable level and also provide an 
ample margin of safety to protect public health (as was proposed) from 
P&R I emission sources. We also have determined that no additional 
requirements are needed to prevent an adverse environmental effect (as 
was proposed).
    We also acknowledge that the wash belt dryers are located in the 
finishing building, which is separate from the polymer building; and at 
proposal, we incorrectly assumed these process vents were front-end 
process vents when in actuality they are considered back-end process 
vents according to NESHAP subpart U. As such, we are clarifying in the 
final rule that the requirements we are finalizing for controlling 
chloroprene from process vents in the Neoprene Production source 
category, not only applies to continuous front-end process vents in 
chloroprene service and batch front-end process vents in chloroprene 
service, but also back-end process vents in chloroprene service. In 
other words, we are finalizing at 40 CFR 63.494(a)(7) a requirement 
that owners and operators reduce emissions of chloroprene from back-end 
process vents in chloroprene service at affected sources producing 
neoprene by venting emissions through a closed-vent system to a non-
flare control device that reduces chloroprene by greater than or equal 
to 98 percent by weight, to a concentration less than 1 ppmv for each 
process vent, or to less than 5 lb/yr for all combined process vents. 
We anticipate that the facility will still need to install an 
additional thermal oxidizer in order to comply with the final 
performance standard for process vents and storage vessels in 
chloroprene service. We also note that while the commenter claims that 
the 3.3 tpy chloroprene emissions from the wash belt dryers were 
reported in their 2022 inventory, we stand by our decision to use the 
facility's 2019 emissions inventory which shows 3.9 tpy chloroprene 
emissions from the wash belt dryers. As previously mentioned, the 
facility's emissions inventory was provided to the EPA pursuant to our 
CAA section 114 request. In particular, the EPA requested emission 
inventories from the past 5 years (i.e., 2016-2020) from the facility's 
operations as part of this request. As 2017 NEI data did not represent 
current controls being employed at Denka Performance Elastomers, LLC, 
the EPA chose to use the most current data it had available and that is 
reflective of current operations and emissions. Given concerns about 
decreased production and emissions in 2020 from the COVID-19 pandemic, 
the EPA elected to use Denka Performance Elastomer, LLC's 2019 
emissions inventory submitted as part of the CAA section 114 request in 
its risk assessment for the SOCMI and Neoprene Production source 
categories in lieu of the 2017 NEI data. Even if we were to revise 
emissions based on the facility's 2022 emissions inventory, we continue 
to believe our cost estimate to install permanent total enclosures, a 
thermal oxidizer, and ductwork and associated support equipment (using 
the procedures in the EPA's 2002 Control

[[Page 42987]]

Cost Manual) is reasonable, and note that cost does not play a role in 
setting standards that are necessary to reduce risk to an acceptable 
level under step one of the Benzene NESHAP approach codified in CAA 
section 112(f). Furthermore, with regard to a commenter's specific 
objections to installing a permanent total enclosure around their wash 
belts/dryers, we note that even though we costed out permanent total 
enclosures for these emission sources in our proposal, there is no 
explicit requirement in the proposed rule, or final rule, to install 
permanent total enclosures around these emission sources. We opted for 
this option as the most conservative way to collect the fugitive 
chloroprene emissions from the wash belts/dryers and route them to a 
control device such as a thermal oxidizer. Nothing in the proposed 
rule, or final rule, prevents the facility from doing something 
different than installing a permanent total enclosure around their wash 
belts/dryers so long as the owner or operator can achieve the emission 
standard we are finalizing at 40 CFR 63.494(a)(7) for back-end process 
vents (i.e., the requirement that owners and operators reduce emissions 
of chloroprene from back-end process vents in chloroprene service at 
affected sources producing neoprene by venting emissions through a 
closed-vent system to a non-flare control device that reduces 
chloroprene by greater than or equal to 98 percent by weight, to a 
concentration less than 1 ppmv for each process vent, or to less than 5 
lb/yr for all combined process vents).
    Even so, we anticipate cost to be less of a concern for the final 
rule given that the facility should be able to use their existing 
thermal oxidizer to meet the revised performance standard (reduce 
chloroprene by greater than or equal to 98 percent by weight) for at 
least some of their process vents and storage vessels in chloroprene 
service.
ii. Wastewater in Chloroprene Service
    Comment: A commenter said that they support the proposed provision 
at 40 CFR 63.501(a)(10)(iv) to revise the Group 1 wastewater stream 
threshold to include wastewater streams in chloroprene service (i.e., 
wastewater streams with total annual average concentration of 
chloroprene greater than or equal to 10 ppmw at any flow rate). 
However, another commenter said the EPA's analysis of the costs and 
emission reductions associated with reducing chloroprene emissions from 
wastewater streams at neoprene production processes (see Docket Item 
No. EPA-HQ-OAR-2022-0730-0092) has several major flaws. The commenter 
said the EPA's analysis suggests that the proposed control requirements 
for wastewater would reduce chloroprene emissions by 17.7 tpy, when in 
fact the emission reductions would be closer to 1 tpy; therefore, the 
EPA's analysis substantially overstates the emission reductions that 
would be achieved, and the efficacy and cost-effectiveness of the 
proposed requirements at 40 CFR 63.501(a)(10)(iv). The commenter 
provided the following critiques of the EPA's analysis:
     there are approximately 13.5 tpy of wastewater in 
chloroprene service that pass through the WWTP, not 26.3, which the EPA 
incorrectly used in their analysis.
     although the EPA acknowledges that some controls may 
already be in place, their analysis goes on to analyze the 
effectiveness of the proposed requirements based on the assumption that 
there are no such controls; however, the facility already employs an 
air stripping system to treat the decanter and kettle line wastewater 
streams. The air stripping occurs in the air sparging tank, which is 
routed to the onsite RTO. Testing suggests that the air sparging tank 
achieves a control efficiency of approximately 95 percent. Thus, of the 
7.5 tpy of chloroprene contained in these 2 streams, all but ~0.4 tpy 
are removed via air stripping and directed to RTO. This amount, ~0.4 
tpy, then goes to the WWTP, which includes a biological treatment 
system that reduces it by approximately 80 percent, meaning that 
chloroprene emissions from the decanter and kettle line streams are 
likely less than 0.1 tpy. Thus, accounting for the control efficiency 
of the air sparging tank and the biologic treatment system, almost 99 
percent of the 7.5 tpy contained in the decanter and kettle line 
wastewater streams is already controlled. Even if steam stripping 
achieves a 99 percent capture efficiency in these streams, it would 
only reduce emissions by about 0.025 tpy (to 0.075 tpy as compared to 
0.1 tpy today).
     based on limited testing of the air stripper rundown 
streams, they contain approximately 6.0 tpy of chloroprene. These 
streams are routed to the outdoor brine pit, which then discharges to 
the WWTP. The EPA did not consider that the WWTP includes biological 
control that currently reduces chloroprene emissions by approximately 
80 percent. It is true that some emissions to air occur as the 
wastewater is conveyed through the outdoor brine pit and to the WWTP, 
but it is incorrect for the EPA to consider it ``uncontrolled.'' 
Assuming the Fe of 68 percent suggested by the EPA, the maximum 
fraction of the mass of chloroprene that could end up as an air 
emission is about 4 tpy before biological control. Applying the 80 
percent estimated biological control removal rate, current emissions 
are approximately 0.8 tpy from the air stripper rundown streams. Even 
if the EPA's assumption of a 99 percent removal efficiency for steam 
stripping is accurate, it would reduce emissions by about 0.8 tpy from 
the stripper rundown streams.
    The commenter concluded that when adding the 0.8 tpy from the 
stripper rundown streams to the 0.1 tpy reduction from the decanter and 
kettle line wastewater streams, the EPA's proposed steam stripping 
requirement is likely to reduce current chloroprene emissions by about 
1 tpy (not by 17.7 tpy as the EPA had determined). The commenter added 
that there is also uncertainty as to whether steam stripping would 
actually achieve 99 percent removal of the low concentrations of 
chloroprene in wastewater given that chloroprene is a halogenated 
alkane, and no information has been presented that is specific to steam 
stripping of chloroprene from wastewater at the concentrations present 
in wastewater at the facility. The commenter deduced that when using 
their expected actual emissions reductions of about 1 tpy, the cost 
effectiveness would be closer to $7.5 million per ton removed (without 
considering the cost of installing and operating a thermal oxidizer 
that would be required under the EPA's proposal to handle the 
chloroprene from the steam stripper unit), and not $426,900 per ton as 
the EPA has estimated.
    Response: The EPA acknowledges the commenters' support for and 
opposition of the proposed wastewater provisions at 40 CFR 
63.501(a)(10)(iv). We are finalizing these provisions as proposed. We 
disagree with the commenter's assertion that 13.5 tpy of wastewater in 
chloroprene service pass through the WWTP. We also disagree that our 
emissions reductions were overestimated. We believe 26.3 tpy of 
wastewater in chloroprene service pass through the WWTP (i.e., the 
amount of chloroprene entering the air sparging tank) based on our 
review of emissions inventory calculations for wastewater entering the 
WWTP. We maintain that 17.7 tpy of emissions reductions is appropriate, 
based on a mass balance of the information provided in the emissions 
inventory calculations. The results of our mass balance suggest that 
our initial analysis is appropriate.
    We also disagree with the commenter and maintain it was appropriate 
to

[[Page 42988]]

assume no controls during our initial analysis such that a steam 
stripper would be placed before the air sparging tank. Simply put, the 
P&R I NESHAP (which references the HON wastewater requirements) 
requires all wastewater collection system components (tanks, surface 
impoundments, containers, individual drain systems, and oil-water 
separators) to be covered and upstream of the wastewater treatment 
process. However, the facility's wastewater treatment system is 
configured with an air sparging tank (air stripper), followed by an 
outdoor brine pit (open to the atmosphere), followed by biological 
treatment. Furthermore, the commenter claims their air stripper 
achieves approximately 95 percent control, but did not provide any data 
to corroborate this control efficiency. When taking the configuration 
of the facility's wastewater treatment system into account, we assumed 
no controls, since wastewater streams flow through a control device 
with an unknown control efficiency directly into an open brine pit.
    Also, contrary to the commenter's remark regarding steam stripper 
performance, we believe the use of 99 percent removal of chloroprene 
from steam stripping is appropriate based on its Fr value. In the 
document titled Analysis of Control Options for Wastewater Streams to 
Reduce Residual Risk of Chloroprene from Neoprene Production Processes 
Subject to P&R I (see Docket Item No. EPA-HQ-OAR-2022-0730-0092), we 
explain that the EPA calculated the Fr values for a variety of HAP 
during the original rulemaking of the HON. The Fr is the fraction of a 
HAP that is stripped from wastewater and is an indicator of the extent 
to which a HAP is effectively removed during the steam stripping 
process. For chloroprene, the Fr has always been 99 percent in Table 9 
to NESHAP subpart G and we maintain this is reflective of the current 
technology.
    Finally, we remind the commenter that, due to the risk associated 
with chloroprene, cost does not play a role in setting standards that 
are necessary to reduce risk to an acceptable level under step one of 
the Benzene NESHAP approach codified in CAA section 112(f). Regardless 
of whether or not emissions reductions were underestimated (which we 
disagree with), a higher cost-effectiveness is not grounds for 
reevaluating the proposed provisions at 40 CFR 63.501(a)(10)(iv).
iii. Chloroprene Facility-Wide Cap
    Comment: A commenter said they support the EPA's proposed rule text 
at 40 CFR 63.483(a)(10) that requires owners and operators to comply 
with a facility-wide chloroprene emissions cap of 3.8 tpy in any 
consecutive 12-month period for all neoprene production emission 
sources. However, another commenter argued that it is impossible to 
know whether the chloroprene emissions cap of 3.8 tpy is simply a 
``backstop'' or an additional requirement that goes beyond the proposed 
requirements to control emissions of chloroprene from maintenance vents 
and PRDs, and process vents, storage vessels, and wastewater ``in 
chloroprene service.'' The commenter asserted that the EPA does not 
appear to have determined whether full compliance with the proposed 
requirements to control chloroprene from maintenance vents and PRDs, 
and process vents, storage vessels, and wastewater ``in chloroprene 
service'' would reduce the facility-wide emissions below the proposed 
chloroprene emissions cap of 3.8 tpy. The commenter also asserted that 
the EPA has not estimated the costs of reducing facility-wide emissions 
below this cap, nor does the EPA provide any details about the type of 
monitoring that would be required to demonstrate compliance with it. 
The commenter argued that given the EPA's determination that the 
chloroprene emissions cap of 3.8 tpy would protect public health with 
an ample margin of safety, the proposed requirements to control 
chloroprene from maintenance vents and PRDs, and process vents, storage 
vessels, and wastewater ``in chloroprene service'' are unlawful if they 
would force the facility to reduce emissions appreciably below 3.8 tpy. 
The commenter said that the EPA does not have authority to require 
emission reductions that go beyond what is necessary to protect public 
health with an ample margin of safety, unless they are based on cost-
effective improvements in control technology under CAA section 
112(d)(6).
    Another commenter provided several reasons why the chloroprene 
emissions cap of 3.8 tpy is inappropriate, including: (1) The EPA back-
calculated this cap from a flawed risk assessment; (2) the cap is 
unverifiable and therefore not enforceable, particularly here where it 
encompasses not only non-flare point sources (which can, with some 
effort, be properly monitored) but also flare and numerous fugitive 
sources (whose emissions simply cannot be tested, monitored, and 
verified); and (3) there have recently been large problems with 
``unknown'' and therefore unreported emissions at the facility (e.g., 
in 2022, the EPA discovered that the facility was using an unpermitted 
brine pit to allow poly-kettle waste to off-gas chloroprene).
    Response: We are not finalizing the proposed requirement at 40 CFR 
63.483(a)(10) that would have required owners and operators to comply 
with a chloroprene emissions cap of 3.8 tpy in any consecutive 12-month 
period for all neoprene production emission sources. The proposed 
facility-wide chloroprene emissions cap was intended to address unknown 
or uncertain emission sources in the Neoprene Production source 
category, including emissions from back-end process operations. 
However, we agree with a commenter that the proposed facility-wide 
chloroprene emissions cap is confusing on how it would be applied 
beyond the proposed requirements for emission sources in chloroprene 
service. Instead, we believe the fenceline monitoring requirements that 
we are finalizing will serve as a reasonable backstop for limiting 
emissions and addressing fugitive and any unknown emission sources in 
the Neoprene Production source category as well as whole-facility 
chloroprene emissions. We are also clarifying in the final rule that 
the requirements we proposed for controlling chloroprene from process 
vents in the Neoprene Production source category apply not only to 
continuous front-end process vents in chloroprene service and batch 
front-end process vents in chloroprene service, but also to back-end 
process vents in chloroprene service. For more details about this, see 
our responses to comments in section IV.A.3.e.i of this preamble.
iv. Other Chloroprene Related Requirements
    Comment: A commenter said they supported the EPA's proposed rule 
text at 40 CFR 63.509 sampling and analysis procedures for owners and 
operators of affected sources producing neoprene to demonstrate that 
process equipment does, or does not, meet the proposed definition of 
being ``in chloroprene service.''
    Response: The EPA acknowledges the commenter's support of the 
sampling and analysis procedures used to determine whether process 
equipment is ``in chloroprene service.'' We are making the following 
minor changes in the final rule to clarify our intent: (1) For process 
vents, we have clarified within the definition of ``in chloroprene 
service'' that the 5 lb/yr chloroprene mass threshold for combined 
process vents be on a EPPU-by-EPPU basis; (2) For storage vessels, we 
are revising the phrasing of ``sampling and analysis is performed as 
specified in Sec.  63.509''

[[Page 42989]]

within the definition of ``in chloroprene service'' to ``the procedures 
specified in Sec.  63.509 are performed''; and (3) we have clarified at 
40 CFR 63.509(a) that the sampling site shall be after the last 
recovery device (if any recovery devices are present) but prior to the 
inlet of any control device that is present and prior to release to the 
atmosphere.
    Comment: A commenter (0172) requested that the EPA recognize in the 
final rule that OGI is effective for detecting chloroprene leaks and 
work with their facility to develop a protocol for LDAR that could be 
included as a compliance option. The commenter claimed that the LDAR 
requirement in the proposed rule would require them to hire additional 
technicians (likely 3 additional workers) and purchase additional 
equipment. The commenter said that they spoke to leak detection experts 
at Montrose Environmental who said that a forward looking infrared 
cooled G304 camera would likely be an effective tool for monitoring and 
detecting chloroprene leaks. The commenter stated that they completed a 
one-day field test with such a camera and found that it was effective 
for detecting chloroprene leaks.
    Response: We did not propose control options for equipment leaks to 
reduce chloroprene risk from the Neoprene Production source category. 
To reduce risk from the Neoprene Production source category to an 
acceptable level, we proposed to require control of chloroprene for: 
(1) Process vents, (2) storage vessels, and (3) wastewater ``in 
chloroprene service.'' We also proposed requirements to reduce 
chloroprene emissions from maintenance vents and PRDs. See section 
III.B.2.b of the preamble to the proposed rule for more details (88 FR 
25080, April 25, 2023). However, we did make an error in the document 
titled Proposed Regulation Edits for 40 CFR part 63 Subpart U: National 
Emission Standards for Hazardous Air Pollutant Emissions: Group I 
Polymers and Resins (see Docket Item No. EPA-HQ-OAR-2022-0730-0066) 
that suggests at 40 CFR 63.502(a)(6) we were proposing to regulate 
certain equipment in chloroprene service.
    The EPA has not provided an OGI-only option for detection for 
chloroprene leaks. Although the commenter mentions a one-day study 
performed by Montrose Environmental on the effectiveness of a 
particular OGI camera's ability to see chloroprene emissions, no 
information from that study was submitted. Additionally, no information 
on the detection level determined during the study or the environmental 
conditions of the study were submitted. Because the detection 
capabilities of OGI cameras are highly influenced by environmental 
conditions, this is important data to understand, and it is unlikely 
that a one-day study would provide information on the capabilities of 
the camera in the range of environmental conditions under which field 
surveys would normally be conducted.
    Although the EPA recently finalized a protocol for using OGI in the 
detection of VOC and methane leaks (40 CFR part 60 appendix K), we note 
that the protocol is geared towards midwave OGI cameras that operate 
with a filter in a particular spectral range (around 3.3 microns) where 
methane and many VOC compounds have a spectral peak. The type of OGI 
camera the protocol is geared towards is not suited to finding leaks of 
chloroprene because chloroprene does not have a strong peak in the 
spectral range of these cameras, which means that only very high leaks 
of chloroprene would be visible to these cameras. The OGI camera 
mentioned by the commenter has a filter in a different spectral range. 
The EPA has not studied this camera to understand its detection 
capabilities, especially in regard to chloroprene, which is a risk 
driver for the source category, nor could the EPA readily find 
information on the ability of this OGI camera to see leaks of 
chloroprene. Because the leak definitions for the source category are 
low, on the order of 500 to 1000 ppm for most equipment, it is 
extremely important to understand the detection capability of an OGI 
camera being used at these sources, especially considering that while 
the OGI cameras the EPA has studied are effective at finding large 
leaks for many compounds, OGI cameras tend to be less effective at 
finding low-level leaks.
    Even so, P&R I facilities currently have an option to use OGI 
through an alternative work practice to detect leaks from equipment at 
40 CFR 63.11(c), (d), and (e). This alternative work practice includes 
provisions for using OGI in combination with annual monitoring using 
EPA Method 21 (and not as an alternative). The alternative work 
practice is not geared towards a particular type of OGI camera, and 
instead, requires owners and operators to perform daily instrument 
checks based on the detection levels and concentration of detectable 
chemicals in the equipment being surveyed.
4. What is the rationale for our final approach and final decisions for 
the risk review?
    As noted in our proposal, the EPA sets standards under CAA section 
112(f)(2) using ``a two-step standard-setting approach, with an 
analytical first step to determine an `acceptable risk' that considers 
all health information, including risk estimation uncertainty, and 
includes a presumptive benchmark on maximum individual lifetime risk 
(MIR) of approximately 1-in-10 thousand'' (88 FR 25080, April 25, 2023; 
see also 54 FR 38045, September 9, 1989.) \47\ We weigh all health risk 
factors in our risk acceptability determination, including the cancer 
MIR, cancer incidence, the maximum TOSHI, the maximum acute HQ, the 
extent and distribution of cancer and noncancer risks in the exposed 
population, multipathway risks, and the risk estimation uncertainties.
---------------------------------------------------------------------------

    \47\ We generally draw no ``bright lines'' of acceptability 
regarding cancer or noncancer risks from source category HAP 
emissions, and it is always important to consider the specific 
uncertainties of the emissions and health effects information 
regarding the source category in question when deciding exactly what 
level of cancer and noncancer risk should be considered acceptable. 
In addition, the source category-specific decision of what 
constitutes an acceptable level of risk should be a holistic one; 
that is, it should simultaneously consider all potential health 
impacts--chronic and acute, cancer and noncancer, and multipathway--
along with their uncertainties, when determining the acceptable 
level of source category risk.
---------------------------------------------------------------------------

    Since proposal, our determinations regarding risk acceptability, 
ample margin of safety, or adverse environmental effects have not 
changed. However, after proposal, commenters provided updated 
information on their facilities, including specific information 
regarding use of the TCEQ modeling guidelines to calculate effective 
flare stack parameters. We updated the risk assessment for the SOCMI 
and Neoprene Production source categories considering the comments 
received on modeling flares. The revised risk assessment (see the risk 
reports, Residual Risk Assessment for the SOCMI Source Category in 
Support of the 2024 Risk and Technology Review Final Rule and Residual 
Risk Assessment for the Polymers & Resins I Neoprene Production Source 
Category in Support of the 2024 Risk and Technology Review Final Rule, 
which are available in the docket for this rulemaking) shows that, 
after application of controls finalized in this rulemaking, the MIR for 
each of the source categories is 100-in-1 million. Therefore, after 
application of the EtO-specific controls for process vents, storage 
vessels, equipment leaks, heat exchange systems, and wastewater, and 
the requirements to reduce EtO emissions from maintenance vents and 
PRDs, we find that the risks are acceptable for the SOCMI source

[[Page 42990]]

category and that the final HON standards will achieve an ample margin 
of safety to protect human health from risks presented by HON emission 
sources. Also, after application of the chloroprene-specific controls 
for process vents, storage vessels, and wastewater, and the 
requirements to reduce chloroprene emissions from maintenance vents and 
PRDs, we find that the risks are acceptable for the Neoprene Production 
source category and that the final P&R I standards will achieve an 
ample margin of safety to protect human health from risks presented by 
neoprene production emission sources.

B. Technology Review for the SOCMI, P&R I, and P&R II Source Categories 
NESHAP and NSPS Review for the SOCMI Source Category

1. What did we propose pursuant to CAA section 112(d)(6) for SOCMI, P&R 
I, and P&R II source categories and CAA section 111(b)(1)(B) for the 
SOCMI source category?
a. NESHAP
    Based on our technology review for the SOCMI, P&R I, and P&R II 
source categories, we proposed under CAA section 112(d)(6) changes to 
the HON and P&R I standards for heat exchange systems, storage vessels, 
and process vents and we proposed no change under CAA section 112(d)(6) 
to the P&R II standards for storage vessels and process vents. The P&R 
II NESHAP currently does not regulate HAP emissions from heat exchange 
systems, but we are finalizing, as proposed, requirements in the P&R II 
NESHAP for heat exchange systems pursuant to CAA section 112(d)(2) and 
(3). In addition, we proposed no change under CAA section 112(d)(6) for 
transfer racks, wastewater streams, and equipment leaks. We also 
proposed fenceline monitoring requirements under CAA section 112(d)(6). 
We provide a summary of our findings, as proposed, in this section.
i. Heat Exchange Systems
    In our technology review for the SOCMI, P&R I, and P&R II source 
categories, we identified one development in practices and processes 
for HON and P&R I heat exchange systems, the use of the Modified El 
Paso Method \48\ for monitoring for leaks from heat exchange systems. 
We determined that this method is more effective in identifying leaks 
and measures a larger number of compounds than the methods previously 
required in the HON and the P&R I NESHAP. After evaluating state and 
Federal regulations requiring the Modified El Paso Method, as well as 
emission data collected for the Ethylene Production RTR (refer to 
section II.D of the proposal preamble (88 FR 25080, April 25, 2023) and 
the Ethylene Production RTR rulemaking docket, Docket ID No. EPA-HQ-
OAR-2017-0357), we proposed pursuant to CAA section 112(d)(6) to 
require use of the Modified El Paso Method with a leak definition of 
6.2 ppmv of total strippable hydrocarbon concentration (as methane) in 
the stripping gas to further reduce HAP emissions from both new and 
existing heat exchange systems, as well as to disallow delay of repair 
of leaks if the measured concentration meets or exceeds 62 ppmv. Based 
on an evaluation of incremental HAP cost effectiveness to increase the 
monitoring frequency, we proposed no changes to the monitoring 
frequency previously required under the HON and the P&R I NESHAP for 
monitoring for leaks from heat exchange systems, which continues to be 
monthly monitoring in the first 6 months following startup of a source 
and quarterly monitoring thereafter. We also proposed to require re-
monitoring at the monitoring location where a leak is identified to 
ensure that any leaks found are fixed. Further, we proposed that none 
of these proposed requirements for heat exchange systems apply to heat 
exchange systems that have a maximum cooling water flow rate of 10 
gallons per minute or less. Finally, we proposed that owners and 
operators may use the current leak monitoring requirements for heat 
exchange systems at 40 CFR 63.104(b) in lieu of using the Modified El 
Paso Method provided that 99 percent by weight or more of the organic 
compounds that could leak into the heat exchange system are water 
soluble and have a Henry's Law Constant less than 5.0E-6 atmospheres-
cubic meters/mol at 25 degrees Celsius. Refer to section III.C.1 of the 
proposal preamble (88 FR 25080, April 25, 2023) for a summary of our 
rationale for selecting the proposed leak method, leak definition, and 
limitation on delay of repairs, as well as our rationale for retaining 
the previous monitoring schedule.
---------------------------------------------------------------------------

    \48\ The Modified El Paso Method uses a dynamic or flow-through 
system for air stripping a sample of the water and analyzing the 
resultant off-gases for VOC using a common flame ionization detector 
analyzer. The method is described in detail in Appendix P of the 
TCEQ's Sampling Procedures Manual: The Air Stripping Method 
(Modified El Paso Method) for Determination of Volatile Organic 
Compound (VOC) Emissions from Water Sources. Appendix P is included 
in the docket for this rulemaking (see Docket Item No. EPA-HQ-OAR-
2022-0730-0032).
---------------------------------------------------------------------------

    For a detailed discussion of the EPA's findings, refer to the 
document titled Clean Air Act Section 112(d)(6) Technology Review for 
Heat Exchange Systems Located in the SOCMI Source Category that are 
Associated with Processes Subject to HON and for Heat Exchange Systems 
that are Associated with Processes Subject to Group I Polymers and 
Resins NESHAP; and Control Option Impacts for Heat Exchange Systems 
that are Associated with Processes Subject to Group II Polymers and 
Resins NESHAP (see Docket Item No. EPA-HQ-OAR-2022-0730-0075).
ii. Storage Vessels
    In our technology review for the SOCMI, P&R I, and P&R II source 
categories, we identified three options for reducing emissions from HON 
and P&R I storage vessels. Refer to section III.C.2 of the proposal 
preamble (88 FR 25080, April 25, 2023) for a summary of the three 
options. Based on our evaluation of the costs and emission reductions 
of each of the three options, we proposed pursuant to CAA section 
112(d)(6) to: (1) Revise the Group 1 HON and P&R I storage vessel 
capacity and MTVP thresholds to reflect the MON existing source 
threshold, which requires existing storage vessels between 38 m\3\ and 
151 m\3\ with a vapor pressure greater than or equal to 6.9 kilopascals 
to reduce emissions of organic HAP by 95 percent utilizing a closed 
vent system and control device, or reduce organic HAP emissions by 
utilizing either an IFR, or an EFR, by routing the emissions to a 
process or a fuel gas system, or by vapor balancing; and (2) in 
addition to requirements specified in option 1, require upgraded deck 
fittings \49\ and controls for guidepoles for all storage vessels 
equipped with an IFR as already required in 40 CR 63, subpart WW.
---------------------------------------------------------------------------

    \49\ This means that we require all openings in an IFR (except 
those for automatic bleeder vents (vacuum breaker vents), rim space 
vents, leg sleeves, and deck drains) to be equipped with a deck 
cover, and the deck cover would be required to be equipped with a 
gasket between the cover and the deck.
---------------------------------------------------------------------------

    For a detailed discussion of the EPA's findings, refer to the 
document titled Clean Air Act Section 112(d)(6) Technology Review for 
Storage Vessels Located in the SOCMI Source Category that are 
Associated with Processes Subject to HON, Storage Vessels Associated 
with Processes Subject to Group I Polymers and Resins NESHAP, and 
Storage Vessels Associated with Processes Subject to Group II Polymers 
and Resins NESHAP (see Docket Item No. EPA-HQ-OAR-2022-0730-0073).

[[Page 42991]]

iii. Process Vents
    In our technology review for the SOCMI, P&R I, and P&R II source 
categories, we identified three options for reducing emissions from HON 
process vents and P&R I continuous front-end process vents. Refer to 
section III.C.3.a of the proposal preamble (88 FR 25080, April 25, 
2023) for a summary of the three options. Based on our evaluation of 
the costs and emission reductions of each of the three options, we 
proposed pursuant to CAA section 112(d)(6) to revise the process vent 
applicability threshold to redefine a HON Group 1 process vent and P&R 
I Group 1 continuous front-end process vent (requiring control) as any 
process vent that emits greater than or equal to 1.0 lb/hr of total 
organic HAP. We also proposed removing the TRE concept in its entirety 
and removing the 50 ppmv and 0.005 scmm Group 1 process vent 
thresholds. In addition, we identified one option for reducing 
emissions from P&R I batch front-end process vents and we proposed 
pursuant to CAA section 112(d)(6) to revise the process vent 
applicability threshold to redefine a P&R I Group 1 batch front-end 
process vent as a process vent that releases total annual organic HAP 
emissions greater than or equal to 4,536 kg/yr (10,000 lb/yr) from all 
batch front-end process vents combined.
    For a detailed discussion of the EPA's findings, refer to the 
document titled Clean Air Act Section 112(d)(6) Technology Review for 
Continuous Process Vents Located in the SOCMI Source Category that are 
Associated with Processes Subject to HON, Continuous Front-end and 
Batch Front-end Process Vents Associated with Processes Subject to 
Group I Polymers and Resins NESHAP, and Process Vents Associated with 
Processes Subject to Group II Polymers and Resins NESHAP (see Docket 
Item No. EPA-HQ-OAR-2022-0730-0094).
iv. Fenceline Monitoring
    We proposed a fenceline monitoring standard for the SOCMI and P&R I 
source categories requiring owners and operators to monitor for any of 
six specific HAP (i.e., benzene, 1,3-butadiene, ethylene dichloride, 
vinyl chloride, EtO, and chloroprene) if their site uses, produces, 
stores, or emits any of them, and conduct root cause analysis and 
corrective action upon exceeding the annual average concentration 
action level set forth for each HAP.
b. NSPS
i. Process Vents
    In our review of NSPS subparts III, NNN, and RRR (for SOCMI air 
oxidation units, distillation operations, and reactor processes, 
respectively), we identified certain advances in process operations 
that were not identified or considered during development of the 
original NSPS. Refer to section III.C.3.b of the proposal preamble (88 
FR 25080, April 25, 2023) for a detailed summary of these advances in 
process operations. Based on our evaluation of statutory factors, 
including costs and emission reductions, we proposed pursuant to CAA 
section 111(b)(1)(B) revised NSPS subparts IIIa, NNNa, and RRRa (which 
are applicable to affected facilities for which construction, 
reconstruction, or modification commences after April 25, 2023). We 
proposed that the revised NSPS subparts encompass a suite of process 
vent requirements, which include: (1) Removing the TRE index value 
concept in its entirety and instead requiring owners and operators to 
reduce emissions of TOC (minus methane and ethane) from all vent 
streams of an affected facility (i.e., SOCMI air oxidation unit 
processes, distillation operations, and reactor processes for which 
construction, reconstruction, or modification commences after April 25, 
2023) by 98 percent by weight or to a concentration of 20 ppmv on a dry 
basis corrected to 3 percent oxygen, or combust the emissions in a 
flare meeting the same operating and monitoring requirements for flares 
that we are finalizing for flares subject to the HON; (2) eliminating 
the relief valve discharge exemption from the definition of ``vent 
stream'' such that any relief valve discharge to the atmosphere of a 
vent stream is a violation of the emissions standard; (3) prohibiting 
an owner or operator from bypassing the APCD at any time, and requiring 
the owner or operator to report any such violation (including the 
quantity of TOC released to the atmosphere); (4) requiring that flares 
used to reduce emissions comply with the same flare operating and 
monitoring requirements as those we have promulgated for flares used in 
SOCMI-related NESHAP; (5) requiring work practice standards for 
maintenance vents during startup, shutdown, maintenance, or inspection 
of any of the air oxidation units, distillation operations, and reactor 
processes affected facilities under the applicable NSPS where the 
affected facility is emptied, depressurized, degassed, or placed into 
service; and (6) adding control device operational and monitoring 
requirements for adsorbers that cannot be regenerated and regenerative 
adsorbers that are regenerated offsite. For a detailed discussion of 
the EPA's findings, refer to the document titled CAA 111(b)(1)(B) 
review for the SOCMI air oxidation unit processes, distillation 
operations, and reactor processes NSPS subparts III, NNN, and RRR (see 
Docket Item No. EPA-HQ-OAR-2022-0730-0011).
ii. Equipment Leaks
    In our review of NSPS subpart VVa (for SOCMI equipment leaks), we 
identified emission reduction measures used in practice related to LDAR 
of certain equipment that achieve greater emission reductions than 
those currently required by NSPS subpart VVa. Refer to section 
III.C.6.b of the proposal preamble (88 FR 25080, April 25, 2023) for a 
summary of these measures. Based on our evaluation of statutory 
factors, including costs and emission reductions, we proposed pursuant 
to CAA section 111(b)(1)(B) a revised NSPS subpart VVb applicable to 
affected facilities for which construction, reconstruction, or 
modification commences after April 25, 2023. The revised NSPS VVb 
includes the same requirements as in NSPS subpart VVa plus a 
requirement that all gas/vapor and light liquid valves be monitored 
monthly at a leak definition of 100 ppm and all connectors be monitored 
once every 12 months at a leak definition of 500 ppm.
    For a detailed discussion of the EPA's findings, refer to the 
document titled CAA 111(b)(1)(B) review for the SOCMI Equipment Leaks 
NSPS Subpart VVa (see Docket Item No. EPA-HQ-OAR-2022-0730-0096).
2. How did the technology review change for the SOCMI, P&R I, and P&R 
II source categories, and NSPS review change for the SOCMI source 
category?
    We are finalizing the results of the NSPS review under CAA section 
111(b)(1)(B) for the SOCMI source category as proposed (88 FR 25080, 
April 25, 2023), with a change to the definition of ``capital 
expenditure'' in NSPS subpart VVb to use a formula that better reflects 
the trajectory of inflation. We are also finalizing the results of the 
technology review pursuant to CAA section 112(d)(6) for the SOCMI, P&R 
I, and P&R II source categories as proposed (88 FR 25080, April 25, 
2023), with some changes to the fenceline monitoring requirements that 
we proposed under the technology review for the SOCMI and P&R I source 
categories, and also a minor change to clarify that, with regard to the 
storage

[[Page 42992]]

vessel portion of the technology review, the Group 1 HON and P&R I 
storage vessel capacity and MTVP thresholds apply to both new and 
existing sources. For fenceline monitoring requirements, the final rule 
establishes two action levels for chloroprene (i.e., one action level 
under CAA section 112(d)(6) and another action level under CAA section 
112(f)) in lieu of only one action level for this HAP, as proposed. We 
are also finalizing: (1) Burden reduction measures to allow owners and 
operators to skip fenceline measurement periods for specific monitors 
with a history of measurements that are at or below certain action 
levels; (2) a clarification that fenceline monitoring is required for 
owners and operators with affected sources that produce, store, or emit 
one or more of the target analytes; (3) a reduction in the requirements 
for the minimum detection limit of alternative measurement approaches; 
(4) clarifications on establishing the monitoring perimeter for both 
sorbent tubes and canisters; (5) clarifications on the calculation of 
[Delta]c when a site-specific monitoring plan is used to correct 
monitoring location concentrations due to offsite impacts; (6) a change 
in the required method detection limit for alternative test methods 
from an order of magnitude below the action level to one-third of the 
action level; and (7) with the exception of fenceline monitoring of 
chloroprene at P&R I affected sources producing neoprene, a change in 
the compliance date in the final rule to begin fenceline monitoring 2 
years (instead of 1 year, as proposed) after the effective date of the 
final rule. For P&R I affected sources producing neoprene, we have 
changed the compliance date for fenceline monitoring of chloroprene to 
begin no later than October 15, 2024, or upon startup, whichever is 
later, subject to the owner or operator seeking the EPA's authorization 
of an extension of up to 2 years from July 15, 2024.
3. What key comments did we receive on the technology review and NSPS 
review, and what are our responses?
a. NESHAP
    The EPA received comments in support of and against the proposed 
technology review. We received only minor comments requesting 
clarifications associated with our technology review for heat exchange 
systems and storage vessels. The comments and our specific responses to 
these issues can be found in the document titled Summary of Public 
Comments and Responses for New Source Performance Standards for the 
Synthetic Organic Chemical Manufacturing Industry and National Emission 
Standards for Hazardous Air Pollutants for the Synthetic Organic 
Chemical Manufacturing Industry and Group I & II Polymers and Resins 
Industry, which is available in the docket for this rulemaking. Based 
on these comments, we are finalizing revisions to require the Modified 
El Paso Method for heat exchange systems, and we are finalizing 
revisions to the Group 1 HON and P&R I storage vessel capacity and MTVP 
thresholds to reflect the MON existing source threshold for both new 
and existing sources.
    We did not receive any comment with regard to the technology review 
for transfer racks and wastewater streams. Furthermore, for equipment 
leaks, the comments were generally either supportive of the 
determination that no cost-effective developments from the technology 
review were found, or that the Agency should re-open and reevaluate the 
MACT standards for new technologies. Based on our review of the 
comments received for equipment leaks, we are finalizing our 
determination that no cost-effective developments exist and that it is 
not necessary to revise these emission standards under CAA section 
112(d)(6). For process vents, the EPA received additional information 
from commenters on costs necessary for control of process vents that 
emit greater than or equal to 1.0 lb/hr of total organic HAP. We also 
received several comments regarding the fenceline monitoring 
requirements that we proposed under the technology review. This section 
provides summaries of and responses to the key comments received 
regarding: (1) The technology review amendments we proposed for HON 
process vents and P&R I continuous front-end process vents, and (2) the 
proposed fenceline monitoring requirements. Comment summaries and the 
EPA's responses for additional issues raised regarding the proposed 
requirements resulting from our technology review for the SOCMI, P&R I, 
and P&R II source categories are in the document titled Summary of 
Public Comments and Responses for New Source Performance Standards for 
the Synthetic Organic Chemical Manufacturing Industry and National 
Emission Standards for Hazardous Air Pollutants for the Synthetic 
Organic Chemical Manufacturing Industry and Group I & II Polymers and 
Resins Industry, which is available in the docket for this rulemaking.
i. Process Vents
    Comment: A commenter said they supported the EPA's proposed rule 
text at 40 CFR 63.113(a)(4) and 40 CFR 63.485(l)(6), (o)(6), (p)(5), 
and (x) that removes the TRE concept in its entirety from both the HON 
and P&R I NESHAP. However, numerous commenters opposed removal and 
provided the following arguments to reinforce their opposition:
     The EPA lacks the statutory authority to remove the TRE 
index value concept because it has offered no supportable basis as to 
why removal would constitute a development in practices, processes, or 
technologies under CAA section 112(d)(6).
     The fact that another source category's standards do not 
include the TRE index value concept is not a development in practice, 
and the EPA offered no argument as to how it could possibly fit within 
that box.
     The fact that some facilities choose to control process 
vents that would be exempt using the TRE index value does not indicate 
that removing the TRE concept is a development in practices, processes, 
or technologies. Electing not to use the TRE is a business choice, not 
a technological development.
     Complexity of an established compliance tool is not a 
technological development.
     The EPA has not adequately supported its proposal to 
remove the TRE concept.
     While it is true that certain facilities may have 
designated process vents with a TRE index value above 1.0 as a Group 1 
process vent, the reason behind this may not necessarily be voluntary 
or driven by the desire to avoid the TRE calculation, but rather 
facilities may be controlling these process vents to comply with state 
or local regulations regarding VOCs or to meet a best available control 
technology (BACT) limit.
     The EPA's rationale for eliminating the TRE index value 
from the HON rule due to variations in other MACT rules is flawed given 
that the EPA did not remove the TRE index value during the revision of 
the MON rule and distinguishing between Group 1 and Group 2 process 
vents in the Ethylene Production source category is irrelevant.
     Even though some process vents with a TRE index value 
above 1.0 are controlled at certain facilities, that does not imply 
that controlling all process vents with TRE index values above 1.0 is 
appropriate or cost-effective.
     Facilities often use source test results to determine TRE 
calculation inputs (even for vent streams with a TRE index value 
greater than 4.0), and this approach is neither complex nor uncertain 
to interpret.

[[Page 42993]]

     Despite the EPA's assertion that enforcing the TRE index 
value ``can be'' arduous due to its theoretical nature, no instances 
have been provided where verifying a TRE index value calculation posed 
challenges for an agency or contradicted actual cost effectiveness at a 
facility. The number of inputs to the TRE index value calculation is 
proportional to the number of measurable organic compounds in the vent 
stream; and some facilities have very few organic compounds in process 
vents, so the inputs are minimal, and if those inputs are determined by 
other allowed methods (e.g., source tests, permit limits), then 
verification of these inputs is clearly not problematic.
     Perceived complexity is not a basis for removing the 
option.
     The TRE index value has been an integral part of many 
technology-based air standards since its initial development, serving 
as a mechanism for determining cost effectiveness and triggering the 
requirements for process vent control (see, e.g., the preamble to the 
1994 HON adoption, which states that the TRE concept is appropriate 
because it ``can be used to reflect all possible combinations of 
various factors that affect emission rates and likelihood of current 
control'' (59 FR 19416) and ``would provide consistency between the 
HON[,] the recently issued [control techniques guidelines] for SOCMI 
process vents. . .[and] the applicability criteria for the three SOCMI 
process vents NSPS'' (59 FR 19418)).
     By considering the TRE index value, an owner or operator 
can allocate their resources more efficiently and concentrate efforts 
and resources on the vents that have the greatest potential for 
emission reduction, maximizing the overall environmental benefit. The 
TRE considers not only the organic HAP emissions but also the 
volumetric flow and net heating value of the vent gas stream, and thus 
it takes into consideration the practicality of controlling relatively 
small organic HAP emission streams using control devices like a flare 
or a vapor incinerator.
     Use of the TRE index value is a holistic approach that 
ensures that the most significant emission sources are targeted for 
control, leading to more effective pollution reduction.
     Uncontrolled Group 2 process vent gas streams typically 
exhibit minimal emissions of HAP and VOC, possess a low net heating 
value, may contain steam or water vapor, and have varying volumetric 
flow rates. Directing these streams to an emission control device, if 
available in the CMPU capable of handling them, is a complex 
engineering problem and would yield negligible emissions reductions. 
Moreover, it would likely necessitate the addition of significant 
amounts of supplemental fuel to combust this type of stream and 
consequently result in additional emissions of carbon monoxide (CO), 
nitrogen oxides (NOX), and CO2 to control a 
relatively small quantity of HAP or VOC emissions.
     It is not clear how the emissions averaging program, as it 
is currently applied under the HON, can continue to exist with the 
requirement to control process vents that are currently designated as 
Group 2 vents. The burden of over-control to generate ``credits'' will 
effectively render the provisions unattainable or useless.
     Many facilities will still be required to comply with TRE-
based determinations according to their title V operating permits and 
requirements under NSPS subparts NNN and RRR.
    Many of the commenters who opposed removing the TRE index value in 
its entirety suggested that the EPA could potentially consider raising 
the TRE index value threshold, such as by aligning it with the value in 
the MON rule or the value indicated in Option 3 of the proposed rule, 
or by setting it at a level agreed upon as cost-effective by the 
industry. Other commenters opposed this suggestion.
    Response: The EPA acknowledges commenters' support for and 
opposition to the removal of the TRE concept from the HON at 40 CFR 
63.113(a)(4) and from the P&R I NESHAP at 40 CFR 63.485(l)(6), (o)(6), 
(p)(5), and (x). We are finalizing the removal of the TRE concept as 
proposed. We stand by the rationale we provided in the preamble to the 
proposed rule (88 FR 25080, April 25, 2023) for removing the TRE 
concept: (1) We identified at least one more recent (than the HON and 
the P&R I NESHAP) chemical manufacturing NESHAP (i.e., ethylene 
production) that does not use the TRE index value as criteria for 
determining whether a process vent should be controlled; (2) based on 
the responses to our CAA section 114 request, we observed that some 
facilities are controlling continuous process vents that are not 
required by the HON and the P&R I NESHAP to be controlled per the 
results of the TRE index value calculation; (3) based on the responses 
to our CAA section 114 request, we observed that facilities are routing 
multiple continuous process vents to a single APCD; (4) determining a 
TRE index value for certain process vent streams is often theoretical, 
can be extremely complicated, and is uncertain; and (5) because the TRE 
index value is largely a theoretical characterization tool, it can be 
very difficult to enforce.
    We disagree with commenters that the removal of the TRE concept 
does not constitute a development in practices, processes, or 
technologies under CAA section 112(d)(6). We noted in the preamble to 
the proposed rule (88 FR 25080, April 25, 2023) that some owners and 
operators do not use the TRE index value to determine whether a vent 
stream is a Group 1 or Group 2 process vent. While we agree with 
commenters that owners and operators control Group 2 vent streams for 
reasons other than the desire to avoid the TRE calculation, the fact is 
that owners and operators are controlling HON and P&R I Group 2 process 
vents (possibly to comply with state or local regulations regarding 
VOCs or to meet a BACT limit), which we consider a development under 
CAA section 112(d)(6). Given that the TRE concept, as some commenters 
pointed out, has been used since the original 1994 HON adoption (and 
even in the 1992 proposed HON rule), we consider owners and operators 
controlling HON and P&R I Group 2 process vents to be an operational 
procedure that was not identified or considered during development of 
the original MACT standards. Additionally, the removal of the TRE 
concept simplifies the determination as to whether owners and operators 
must control a vent stream and thus the applicability process is easier 
to implement.
    We disagree with commenters' assertion that the EPA did not provide 
evidence that the TRE concept is largely theoretical and, as a result, 
difficult to verify. As identified in the document titled Clean Air Act 
Section 112(d)(6) Technology Review for Continuous Process Vents 
Located in the SOCMI Source Category that are Associated with Processes 
Subject to HON, Continuous Front-end and Batch Front-end Process Vents 
Associated with Processes Subject to Group I Polymers and Resins 
NESHAP, and Process Vents Associated with Processes Subject to Group II 
Polymers and Resins NESHAP (Docket Item ID No. EPA-HQ-OAR-2022-0730-
0094), one facility that received the CAA section 114 request provided 
over 300 pages of modeled runs used to determine certain 
characteristics of their continuous process vents to be utilized as 
part of the TRE index value calculations. Reviewing this information 
revealed that in many cases the facility struggled to unify the modeled 
runs with actual conditions at the facility and in some cases made 
arbitrary decisions to allow the model to function. While we agree with 
commenters that the TRE index

[[Page 42994]]

value can be derived from less theoretical methods, other responses to 
the CAA section 114 request did not indicate how parameters used in the 
TRE index value calculations were determined, and commenters did not 
provide sufficient information to show which methods were most common 
throughout industry. Given the theoretical nature of the TRE index 
value, the EPA maintains that verifying TRE index values is arduous 
because it can involve relying on significant process knowledge in 
order to confirm HAP compositions of vent streams, vent stream 
flowrates, vent stream net heating values, and hourly emissions. It may 
also require verification of other facility assumptions (e.g., 
operational conditions and constraints) especially if modeling was 
used.
    We agree with commenters that the TRE index value has been an 
integral part of many technology-based air standards since its initial 
development. In fact, we said as much in the document titled Clean Air 
Act Section 112(d)(6) Technology Review for Continuous Process Vents 
Located in the SOCMI Source Category that are Associated with Processes 
Subject to HON, Continuous Front-end and Batch Front-end Process Vents 
Associated with Processes Subject to Group I Polymers and Resins 
NESHAP, and Process Vents Associated with Processes Subject to Group II 
Polymers and Resins NESHAP (Docket Item ID No. EPA-HQ-OAR-2022-0730-
0094). The TRE concept is almost 40 years old as it was first 
introduced in a December 1984 EPA document (EPA-450/3-84-015; see 
attachment to Docket Item No. EPA-HQ-OAR-2022-0730-0094). However, even 
if it has been integral, certain aspects of its underlying development 
are clearly no longer applicable or appropriate. For example, the EPA 
stated in the 1984 supporting materials (EPA-450/3-84-015) that the 
Agency attempted to make the TRE index independent of inflation (e.g., 
the EPA assumed fixed relative costs of various resources, such as 
carbon steel and electricity), yet it is impossible to ignore inflation 
in the TRE calculations due to the time that has passed since it was 
developed (e.g., costs of carbon steel and electricity have undoubtedly 
increased since the development of the TRE index).
    Although the TRE index value may allow owners and operators to 
allocate resources efficiently and ensure that the most significant 
emission sources are targeted for control, the current use of the TRE 
index value is only based on controlling a single process vent with a 
single APCD. This is an unrealistic scenario when compared to how 
chemical manufacturing facilities actually control their process vents; 
and it is much more likely that a facility routes numerous process 
vents to the same APCD (and this is evident from observing the 
responses to our CAA section 114 request).
    We agree with commenters that the removal of the TRE concept may 
lead to emissions increases due to the use of supplemental fuel in new 
APCDs that are potentially needed to control Group 2 streams that are 
currently uncontrolled; and we acknowledged this in our preamble to the 
proposed rule (88 FR 25080, April 25, 2023) as well as in the RIA 
accompanying the proposal. However, based on other comments received 
and discussed elsewhere in this section of this document (regarding the 
use of low volumetric flow rates in our original proposed cost 
estimate), we revised our cost analysis to account for higher flow 
rates to the APCD. As a result of this flow rate adjustment, additional 
supplemental fuel was needed to control Group 2 vent streams that 
exhibit minimal emissions of HAP and VOC, possess a low net heating 
value, and may contain steam or water vapor. Even so, at proposal, we 
overestimated the amount of supplemental fuel that would be needed 
nationwide (168 MMscf/yr) to control Group 2 vent streams that exhibit 
minimal emissions of HAP and VOC, and we continue to believe this 
estimate is conservatively high even after revising our cost analysis. 
For this reason, we are not revising our estimate of secondary impacts 
(including emissions of CO, CO2, NOX (including 
nitrous oxide (N2O)), particulate matter, and sulfur dioxide 
(SO2)).
    With regard to the commenters' assertion that many facilities will 
still be required to comply with TRE-based determinations according to 
their title V operating permits and requirements under NSPS subparts 
NNN and RRR, we note that we are simplifying the HON overlap provisions 
for NSPS subparts III, NNN, and RRR in the final rule (i.e., we are 
finalizing, as proposed, that pursuant to 40 CFR 63.110(d)(1), (d)(4), 
(d)(7), and (d)(10) process vents subject to the emission standards in 
HON that are also subject to the NSPS subpart III, NNN, and/or RRR are 
only required to comply with the HON). Also, facilities already have 
general obligations under title V reopening for cause and 5-year 
renewals to ensure that permits include all requirements applicable to 
a facility.
    Concerning emissions averaging, we note that the provisions 
experienced no significant changes as a result of removing the TRE 
concept. The only explicit references to the TRE concept as part of the 
emissions averaging provisions are at 40 CFR 63.150(g)(2)(iii)(B)(2) 
with respect to a vent transitioning from a Group 1 process vent to a 
Group 2 process vent and at 40 CFR 63.150(m)(2)(i) related to 
obligations associated with carbon absorbers, adsorbers, or condensers 
not equipped with a control device. Both of these references are 
captured as no longer being required at 40 CFR 63.113(a)(4)(xii) and 40 
CFR 63.113(a)(4)(xiii), respectively, and do not affect applicability. 
Emissions averaging has always been an optional provision with its 
burden falling on owners or operators to decide if it was appropriate 
or cost-effective to over-control certain streams while under-
controlling other streams. This does not change as a result of 
redefining Group 2 process vents to be those streams containing less 
than 1.0 lb/hr of HAP. In addition, we note that credits may be 
generated from controlling Group 1 process vents at a higher nominal 
efficiency than the reference technology and from utilizing pollution 
prevention measures either independently or in combination with Group 1 
process vents as specified at 40 CFR 63.150(c). Thus, even if a 
facility determines that controlling Group 2 process vents is 
infeasible, there are other avenues to pursuing the emission averaging 
provisions.
    Finally, we disagree with the commenters' suggestion to raise the 
TRE index value threshold. Regarding a commenter's assertion that 
removing the TRE concept is flawed given that no action was taken on 
the TRE concept in the MON RTR, we note that we did not have data 
related to Group 2 process vents while developing revisions to the MON. 
Setting an emission threshold with no knowledge as to which Group 2 MON 
vent streams would be impacted and without knowing the potential cost 
or reductions associated with that revision would not have been 
appropriate. Thus, we did not identify any cost-effective developments 
in practices, processes, or control technologies for process vents. 
However, as part of this rulemaking, the Group 2 process vent data was 
collected via a CAA section 114 request. Our analysis of the Group 2 
process vent data shows that removing the TRE concept and installing a 
1.0 lb/hr of HAP emission threshold is of a similar cost effectiveness 
to raising the TRE index value to 5.0. However, for the reasons stated 
earlier in this document, removing the TRE concept was selected.

[[Page 42995]]

Given that we determined that a TRE index value of 5.0 was cost 
effective but opted to remove the TRE concept instead, it would be 
unreasonable to finalize a TRE index value of 3.0 based on the 
considerations discussed above and the decreased potential impact.
    Comment: Commenters said they opposed the EPA's proposed rule text 
at 40 CFR 63.101 and 40 CFR 63.113(a)(1) and (2) that would remove the 
50 ppmv and 0.005 scmm Group 1 process vent thresholds from the Group 1 
process vent definition and that would instead require owners and 
operators of process vents that emit greater than or equal to 1.0 lb/hr 
of total organic HAP to either reduce emissions of organic HAP using a 
flare meeting the proposed operating and monitoring requirements for 
flares in NESHAP subpart F or reduce emissions of total organic HAP or 
TOC by 98 percent by weight or to an exit concentration of 20 ppmv.
    A commenter requested that the EPA explain how it arrived at a 1 
lb/hr control threshold. The commenter said that while the simplicity 
of a 1 lb/hr threshold is admittedly appealing, it is overly 
simplistic, and because the EPA did not supply any justification for 
the choice of 1 lb/hr, it appears to be an arbitrary and capricious 
threshold value.
    Another commenter requested that if the EPA decides to keep the 
proposed Group 1 process vent definition with the 1.0 lb/hr total 
organic HAP mass flow rate threshold, then these proposed revisions 
should apply only to new sources in the HON. The commenter asserted 
that facilities with new sources will have greater flexibility in 
selecting cost-effective control options during the design and 
construction phase than the very limited, and climate impacting, 
options available to retrofit existing sources. The commenter added 
that additional controls would have virtually no effect on improving 
ample margin of safety or additional protection of public health.
    Response: Commenters did not provide sufficient information 
detailing why requiring the control of process vents that emit greater 
than 1.0 lb/hr of total organic HAP would be infeasible beyond the 
arguments related to the removal of the TRE concept which are addressed 
in response to another comment in this section of this preamble. 
Consequently, we are finalizing rule text, as proposed at 40 CFR 63.101 
and 40 CFR 63.113(a)(1) and (2), that removes the 50 ppmv and 0.005 
scmm Group 1 process vent thresholds from the Group 1 process vent 
definition and instead requires owners and operators to control process 
vents that emit greater than or equal to 1.0 lb/hr of total organic 
HAP.
    We disagree with the commenters' contention that the 1.0 lb/hr of 
total organic HAP threshold is arbitrary and capricious. As stated in 
the preamble to the proposed rule (88 FR 25080, April 25, 2023), we 
arrived at the 1.0 lb/hr of total organic HAP threshold using detailed 
information for 50 Group 2 continuous process vents that was provided 
by 9 of the 13 HON facilities (including 1 P&R I facility collocated 
with a HON facility) that received the CAA section 114 request.
    We started by performing an analysis of the 50 Group 2 continuous 
process vents for a simple control scenario. Using vent stream 
flowrates, vent stream net heating values, VOC and HAP emission rates 
(which we obtained from TRE index value calculations that facilities 
provided in their response to the CAA section 114 request), and the 
methodology from the sixth edition of the EPA Air Pollution Control 
Cost Manual; we calculated a cost for installing ductwork and a blower 
on each vent, assuming each of these vents could be routed to an 
existing control device achieving 98 percent by weight emission 
reduction. Given that many of the Group 2 continuous process vents have 
a very low flow rate and/or emission rate, we found that even 
installing simple ductwork and a blower would not be cost-effective for 
the majority of these vents. However, we did identify 23 of these Group 
2 continuous process vents (a subset of the 50 Group 2 process vents 
from responses to our CAA section 114 request) for which we found this 
scenario to be cost-effective (i.e., $1,100 per ton of VOC/HAP or 
less).
    We then reviewed mass flow rates of total organic HAP within this 
subset of Group 2 continuous process vents to develop two different 
thresholds (i.e., 0.10 lb/hr and 1.0 lb/hr) for consideration. We 
estimated that 48 HON facilities operating 287 HON Group 2 process 
vents (96 of which are already voluntarily controlled and 191 that are 
not currently controlled) and 3 P&R I facilities operating 30 P&R II 
Group 2 continuous front-end process vents (in which all 30 are not 
currently controlled) would be impacted if we implemented a 0.10 lb/hr 
total organic HAP mass flow rate threshold. Conversely, only 16 HON 
facilities operating 48 HON Group 2 process vents (32 of which are 
already voluntarily controlled and 16 that are not currently 
controlled) and 3 P&R I facilities operating 9 P&R I Group 2 continuous 
front-end process vents (in which all 9 are not currently controlled) 
would be impacted if we implemented a 1.0 lb/hr total organic HAP mass 
flow rate threshold. We then estimated costs to control each Group 2 
continuous process vent scenario and ultimately concluded that only 
those streams with greater than or equal to 1.0 lb/hr of total organic 
HAP would be cost-effective to control. The details of this analysis 
are discussed in the document titled Clean Air Act Section 112(d)(6) 
Technology Review for Continuous Process Vents Located in the SOCMI 
Source Category that are Associated with Processes Subject to HON, 
Continuous Front-end and Batch Front-end Process Vents Associated with 
Processes Subject to Group I Polymers and Resins NESHAP, and Process 
Vents Associated with Processes Subject to Group II Polymers and Resins 
NESHAP (Docket Item ID No. EPA-HQ-OAR-2022-0730-0094).
    We also disagree with the commenter that the 1.0 lb/hr of total 
organic HAP threshold should apply only to new sources in the HON. In 
response to another comment reflected elsewhere in this section of this 
preamble, we have determined that the threshold is cost-effective for 
existing sources.
    Finally, with regard to comments suggesting that additional 
controls would have virtually no effect on improving ample margin of 
safety or additional protection of public health, we note that these 
provisions are finalized under the authority of the technology review 
pursuant to CAA section 112(d)(6), which requires us to revise 
standards as necessary and does not obligate us to consider health 
impacts or generate an ample margin of safety.
    Comment: Commenters suggested that the EPA significantly 
underestimated the cost of installing an additional thermal oxidizer 
and that therefore the cost effectiveness evaluation for removing the 
TRE concept is not correct. Many of these commenters contended that the 
fact that a control device has the capability to control multiple 
process vents does not automatically imply that controlling all vents 
together is cost-effective in every scenario; if the cumulative 
emissions from the Group 2 process vents are relatively low, it would 
not be economically viable to control all of them using a single 
control device. A commenter said that although it is reasonable to 
assume that a single new control device will be installed for 
facilities that will be controlling existing Group 2 process vents with 
emissions greater than 1.0 lb/hr, the use of 10 scfm for determining a 
total capital investment (TCI) for the new control device is not 
representative. The

[[Page 42996]]

commenter contended that although these vents are expected to have 
lower volumetric flow rates than many existing Group 1 vents, there are 
logistical and safety concerns that must be considered when designing a 
closed vent system and thermal oxidizer that necessitate higher flow 
rates. The commenter added that there are multiple facilities with more 
than one of these types of vents per facility; thus, multiple vents 
will need to be collected into a common system which will correspond to 
a higher flow rate. The commenter said that a reasonable low-end 
estimate for a new single thermal oxidizer for controlling these 
process vents is closer to a $1,000,000 TCI. The commenter also noted 
that capital costs could range from $5,000,000 to $15,000,000. The 
commenter added that for facilities that produce chlorinated compounds, 
this cost would be higher because any new thermal oxidizer will need to 
be equipped with acid gas and dioxin/furan controls. Another commenter 
agreed that facilities that produce chlorinated compounds would incur 
higher costs but contended that additional controls for a facility's 
Group 2 process vents would cost at least $50,000,000 in engineering 
and design, equipment, and installation costs.
    Another commenter said that for their facility, the addition of a 
single control device, associated piping, instrumentation, engineering, 
and installation to control 11 process vents (that are currently 
considered Group 2 under the HON) will cost $55,000,000, or 
approximately $925,000/ton of HAPs. Another commenter argued that 
emission sources that are long distances away from existing control 
devices (e.g., a tank in a remote tank farm) and streams not compatible 
with a facility's existing control equipment are no more economically 
feasible for additional controls now than when the HON was originally 
promulgated.
    Response: Several commenters provided us with their own capital 
cost estimates for controlling Group 2 continuous process vents with 
greater than or equal to 1.0 lb/hr of total organic HAP, resulting in a 
very wide range of capital costs (i.e., $1,000,000 to $55,000,000). 
However, the commenters did not provide information to fully support 
these capital costs. For example, commenters did not provide the number 
of streams nor the flow rate for the new streams needing control, did 
not provide any related emissions reductions from controlling these 
streams, and did not provide the annual cost for their scenario. As 
such, it was not possible to fully evaluate the commenters' provided 
capital cost data.
    However, we do agree with commenters that our proposed cost 
estimate underestimated flow rates needed to route Group 2 continuous 
process vents with greater than or equal to 1.0 lb/hr of total organic 
HAP to APCDs. Although we still believe the use of the EPA's control 
cost template to estimate the cost of installing a new recuperative 
thermal oxidizer is appropriate (to control a Group 2 continuous 
process vent with greater than or equal to 1.0 lb/hr of total organic 
HAP), we revised our estimates to reflect the limitations of the 
correlations associated with the EPA's control cost template which 
starts with a flow rate of 500 scfm. With these corrections, we 
estimate the average TCI to install a new recuperative thermal oxidizer 
(for both the HON and the P&R I NESHAP) is about $167,000 (as opposed 
to the $66,000 that we proposed); however, our estimate is still much 
lower than the wide range of cost estimates provided by commenters. One 
possible explanation for this difference in cost estimates is that 
commenters may have used a much higher flow rate (e.g., 5,000 scfm as 
opposed to 500 scfm) and a ``Regenerative Thermal Oxidizer'' in their 
cost analysis instead of a ``Recuperative Thermal Oxidizer.'' Moreover, 
commenters did not provide supporting information for their estimated 
capital costs, so we do not have a way to corroborate this possible 
explanation.
    In light of the fact that commenters were generally concerned about 
the cost estimate, we performed additional analyses to evaluate the 
cost effectiveness of removing the TRE concept from the HON and the P&R 
I NESHAP. Using a TCI of $1,000,000 as provided by the commenter, and 
the EPA's control cost template (for installing a new recuperative 
thermal oxidizer with 70 percent energy recovery), we estimated an 
annual cost of approximately $330,000 (for the HON) and $318,000 (for 
the P&R I NESHAP). Applying this annual cost to our estimated number of 
HON facilities that would need to install a thermal oxidizer and to our 
estimated HAP emissions reductions for the HON of 538 tpy, we 
calculated a cost effectiveness of about $9,830 per ton, which we 
consider to be cost-effective. Applying this annual cost to our 
estimated number of P&R I facilities that would need to install a 
thermal oxidizer and to our estimated HAP emissions reductions for the 
P&R I NESHAP of 130 tpy, we calculated a cost effectiveness of about 
$7,440 per ton. It is important to note that our analysis considers 
that 16 HON facilities operating 48 HON Group 2 process vents (32 of 
which are already controlled by an existing APCD and 16 that are not 
currently controlled) and 3 P&R I facilities operating 9 P&R I Group 2 
continuous front-end process vents (in which all 9 are not currently 
controlled) would be impacted by the 1.0 lb/hr total organic HAP mass 
flow rate threshold. We estimated these impacts using the Group 2 
process vent data from responses to our CAA section 114 request. As 
part of our reevaluation, we also revised our HAP emissions reduction 
estimate for the HON and P&R I process vents that are not currently 
controlled to reflect the average HAP emissions reductions from the 
three HON Group 2 process vents and five P&R I Group 2 process vents 
that would be impacted by the 1.0 lb/hr total organic HAP mass flow 
rate threshold (based on data from responses to our CAA section 114 
request). In our proposal, we took the lowest HAP emission reduction 
based on a single HON process vent and did not appropriately account 
for the other HON process vents for which we had data. We corrected a 
similar issue for the P&R I NESHAP. Therefore, our final calculation 
for estimating the cost effectiveness for removing the TRE concept in 
its entirety from the HON includes a total HAP and VOC reduction of 538 
tpy (and not 436 tpy as proposed) and for the P&R I NESHAP, a total HAP 
and VOC reduction of 130 tpy (and not 51 tpy as proposed). It is also 
possible that the actual emissions reductions may be higher than our 
estimate because the higher capital costs provided by industry are 
likely to be for thermal oxidizers that are sized to control higher 
flow streams with more HAP emissions. For further details on how we 
revised our estimates of cost and HAP emissions reductions, see the 
document titled Clean Air Act Section 112(d)(6) Technology Review for 
Continuous Process Vents Located in the SOCMI Source Category that are 
Associated with Processes Subject to HON, Continuous Front-end and 
Batch Front-end Process Vents Associated with Processes Subject to 
Group I Polymers and Resins NESHAP, and Process Vents Associated with 
Processes Subject to Group II Polymers and Resins NESHAP--FINAL, which 
is available in the docket for this rulemaking.
    Absent additional detailed information from commenters, we are 
finalizing the removal of the TRE concept as proposed and are requiring 
control for process vents that emit greater than or equal to 1.0 lb/hr 
of total organic HAP. We also believe this is

[[Page 42997]]

reasonable given that a 1.0 lb/hr total organic HAP mass flow rate 
threshold for continuous HON and P&R I process vents aligns more 
closely with the batch process vent control threshold in the MON and 
the NESHAP for Chemical Manufacturing Area Sources. In each of these 
NESHAP, the applicability threshold of 10,000 lb/yr per process is used 
for batch process vents.
    Comment: Commenters observed that the EPA's favorable cost-
effectiveness outcome is based on emissions reductions that have 
already occurred and that will not occur as a result of the proposed 
standards (and thus should not be used in the calculus). The commenters 
remarked that the EPA's final calculation for estimating the cost 
effectiveness for removing the TRE concept in its entirety included a 
total annual cost of $3,150,000 and a HAP and VOC reduction of 436 tpy. 
The commenters pointed out that process vents that are already 
voluntarily controlled account for 366 tpy of the total reduction even 
though they will not have emissions reductions as a result of 
implementing the new proposed definition of a Group 1 process vent. The 
commenters argued that if the EPA determines that the emissions 
reductions from these vents should be included in the analysis, the 
Agency must account for the entire cost associated with controlling 
these emissions (i.e., annual costs associated with operating a thermal 
oxidizer) rather than only the costs associated with the installation 
and operation of ductwork and blowers. The commenters added that if 
there are no emissions reductions expected from process vents that are 
already voluntarily controlled, then the cost effectiveness analysis 
should be revised such that it does not include reductions from these 
vents.
    Response: The EPA maintains that the emission reductions associated 
with removing the TRE concept and redefining Group 1 process vents to 
include process vents emitting greater than 1.0 lb/hr of HAP are 
reasonable, and the EPA is not making any revisions as a result of this 
comment. Commenters are correct in stating that 366 tpy of HAP emitted 
by HON process vents exceeding 1.0 lb/hr of HAP are already voluntarily 
controlled. However, the emission reductions are presented on a basis 
of allowable emissions. Previously, there were no requirements for 
process vents exceeding 1.0 lb/hr of HAP. Therefore, under the previous 
rulemaking, all emissions from these vents were allowable, regardless 
of whether some facilities were voluntarily controlling these emissions 
or not. By setting the emission threshold of 1.0 lb/hr of HAP, the 
allowable emissions are restricted, resulting in the 366 tpy of 
emission reductions that the EPA utilized to determine the cost 
effectiveness of removing the TRE concept and redefining Group 1 
process vents. We note that we updated our total HAP reductions and 
annual cost estimates in response to a comment reflected elsewhere in 
this section of this preamble. For details on how we revised our 
estimate of cost and HAP emissions reductions, see the document titled 
Clean Air Act Section 112(d)(6) Technology Review for Continuous 
Process Vents Located in the SOCMI Source Category that are Associated 
with Processes Subject to HON, Continuous Front-end and Batch Front-end 
Process Vents Associated with Processes Subject to Group I Polymers and 
Resins NESHAP, and Process Vents Associated with Processes Subject to 
Group II Polymers and Resins NESHAP--FINAL, which is available in the 
docket for this rulemaking.
    We also disagree with commenters that annual operating costs should 
be considered for the control devices that are controlling the 
voluntarily controlled streams. These existing control devices are 
controlling other streams that are regulated (e.g., controlling HON 
Group 1 process vents), thus the control devices would continue 
operating regardless of whether the Group 2 streams are sent to them or 
not.
    Comment: Commenters requested that the EPA add EPA Method 320 to 40 
CFR 63.115(g)(2) and (3) and allow companies to use measurements or 
testing conducted within the last 5 years to initially demonstrate that 
a process vent is a Group 2 process vent under 40 CFR 63.115(g) 
provided that: (1) The prior measurement or test was conducted using 
the same methods specified in 40 CFR 63.115(g), and (2) either no 
process changes have been made since the test, or the owner or operator 
can demonstrate that the results of the measurement or test, with or 
without adjustments, reliably demonstrate compliance with 40 CFR 
63.115(a) despite process changes.
    A commenter also requested that the EPA allow companies to use 
engineering calculations or process knowledge to initially demonstrate 
that a process vent is a Group 2 process vent under 40 CFR 63.115(g). 
The commenter pointed out that they already conducted testing and 
sampling procedures on their emission points corresponding to the EPA's 
CAA section 114 request which cost $20,000 to $30,000 for a single 
process vent. The commenter added that testing every vent stream is not 
necessary where an owner or operator has engineering calculations or 
process knowledge to demonstrate that a vent stream is a Group 2 
process vent; and historically, under the group determination 
procedures for process vents, the owner or operator of a Group 2 
process vent with a TRE index value greater than 4.0 could use 
measurements, engineering assessments, and calculations to determine 
the TRE index value of the vent stream. The commenter also said that 
one of their facilities continuously monitors vent flow and HAP 
concentration from two HON process vents when they are routed to 
atmosphere and uses the calculated TRE index value to demonstrate that 
the vents remain Group 2 on an ongoing basis. The commenter said that 
this alternative monitoring approach was requested and approved due to 
the variability of HAP emissions from those vents; and generally, the 
calculated TRE index value remains well above 5.0. The commenter 
claimed that this alternative monitoring is used when the site thermal 
oxidizer is down for preventive maintenance; and meeting the proposed 
new process vent requirements would require either a significant 
investment in new control equipment or shutdown of the process during 
thermal oxidizer maintenance.
    Response: We are revising the final rule based on the commenter's 
request to add EPA Method 320 to 40 CFR 63.115(g)(2) and (3) and allow 
for certain previously conducted performance tests to be exempt from 
the Group 2 demonstration requirements at 40 CFR 63.115(g) provided the 
owner or operator can demonstrate: (1) No changes have been made to the 
process since the time of the previously conducted measurement or 
emission test; (2) the previously conducted measurement or emission 
test was conducted using the same methods specified in 40 CFR 
63.115(g); and (3) the previously conducted measurement or emission 
test was completed within the last 60 months. However, we disagree with 
the commenters' request to allow companies to use engineering 
calculations or process knowledge to initially demonstrate that a 
process vent is a Group 2 process vent under 40 CFR 63.115(g). As with 
our concerns relative to the TRE index value, the ability to use 
assessments leads to greater uncertainty with regard to 
characterization of vent streams and their emission potential. We note 
that as explained in section IV.C.3.e of this preamble, we are 
finalizing language in the ``C'' and ``Q'' terms of the equations

[[Page 42998]]

at 40 CFR 63.115(g)(3)(ii) and (g)(4)(iv) allowing the use of 
engineering calculations to determine concentration or flow rate only 
in situations where measurements cannot be taken with EPA reference 
methods.
ii. Fenceline Monitoring
    Comment: Numerous commenters supported the EPA's proposal to 
require fenceline monitoring at facilities in the SOCMI and P&R I 
source categories that use, produce, store, or emit benzene, 1,3-
butadiene, chloroprene, EtO, ethylene dichloride, or vinyl chloride. 
These commenters also said they support the requirement to conduct root 
cause analysis and corrective action. In addition, some commenters 
voiced their support for requiring monitoring data to be made available 
to the public in the WebFIRE database, allowing communities to have 
access to information that impacts them. Some commenters said the 
fenceline monitoring technology has proven to be a valuable tool for 
petroleum refineries to timely detect problems and to address them more 
quickly, substantially reducing emissions from leaks and other 
fugitives. At least one commenter said fenceline monitoring can provide 
numerous benefits, including assisting in identifying an accidental 
release, and in the event of an accidental release, give the community 
immediate notice of the emergency and any necessary mitigation 
responses they should employ (shelter in place, close windows, 
evacuate, etc.). This commenter added that fenceline monitoring can 
also: help communities advocate for vigorous enforcement of regulatory 
requirements; push companies to use safer chemicals; alert and educate 
friends, family members, and community members; and encourage the media 
to report on polluting facilities in their areas. The commenter also 
suggested that facilities can use fenceline monitoring data to take the 
initiative to improve safety at their operations. Other commenters 
requested that EtO emissions be required to be monitored by third-party 
companies. The commenters explained that current laws in some states 
allow facilities to monitor their own emissions, which could cause 
underreported emissions.
    A commenter argued that fenceline monitoring requirements are 
crucial in protecting the communities referred to by the commenter as 
Cancer Alley, especially in St. John the Baptist Parish, which the 
commenter claimed has the highest cancer rates in the country. The 
commenter stated that more and more residents are either facing a 
cancer diagnosis or know someone, such as an immediate family, 
diagnosed with cancer; and asthma rates and hospitalizations from 
asthma are ever-increasing, especially amongst children. The commenter 
also said the area is facing increased weather events brought about by 
climate change. Citing an analysis by the Times Picayune and Advocate 
newspapers, the commenter said that 740 toxic sites are at risk from 
storms, with most of those plants concentrated in the area the 
commenters refer to as Cancer Alley. The commenter said that after 
experiencing numerous storms, they personally witnessed the flaring of 
surrounding plants, including the plants that produce EtO, and are 
concerned about the increase of pollution before, during, and after 
weather events.
    On the contrary, other commenters opposed the EPA's proposal to 
require fenceline monitoring at facilities in the SOCMI and P&R I 
source categories that use, produce, store, or emit benzene, 1,3-
butadiene, chloroprene, EtO, ethylene dichloride, or vinyl chloride. 
These commenters primarily argued that the EPA exceeded its authority 
under CAA section 112(d)(6) because fenceline monitoring is not a 
``development[] in practices, processes, and control technologies'' for 
fugitive EtO emissions. Commenters in opposition of fenceline 
monitoring made the following points about the EPA's assertion of 
authority to require fenceline monitoring:
     Fenceline monitoring has been in existence for years, but 
as recently as 2020 the EPA concluded (in the MON in response to 
Comment 40 in the document titled Summary of Public Comments and 
Responses for the Risk and Technology Review for Miscellaneous Organic 
Chemical Manufacturing, see Docket Item No. EPA-HQ-OAR-2018-0746-0200) 
that they were ``not aware of any methodology or technology with the 
necessary accuracy, precision, and detection sensitivity to require 
fenceline monitoring for EtO.''
     It is unclear what standard the EPA is reviewing or how 
fenceline monitoring constitutes a review of the existing standards 
with respect to ``developments in practices, processes, and control 
technologies.''
     The EPA does not explain how fenceline monitoring, which 
by itself does not reduce emissions, is a development.
     The EPA does not provide any analysis as to how ``root 
cause analysis and corrective action'' are developments with respect to 
any particular unit/unit type.
     The EPA does not adequately explain how monitoring methods 
are a development nor does the EPA explain what development category 
fenceline monitoring allegedly falls into (i.e., a work practice 
standard that was not considered previously).
     According to the proposed rule, at least in places, 
fenceline monitoring (coupled with root cause analysis and corrective 
action) is a work practice standard ``that is a development in 
practices considered under CAA section 112(d)(6) for the purposes of 
managing fugitive emissions''; however, the EPA considered two 
monitoring methods--not action levels, root cause analysis, or 
corrective action--as developments in practices, and it is unclear how 
monitoring methods fall under any other of the broad categories of 
developments previously defined by the EPA.
     If the root cause analysis and the corrective action 
requirements are the work practice standards--as the EPA stated in the 
proposed NESHAP for EtO commercial sterilization and fumigation 
operations--then how are monitoring methods a work practice standard? 
(And if they are not, they are not a development that can be considered 
under CAA section 112(d)(6)?).
     Adding data quality requirements and existing best 
practices does not render EPA Method 327 a new development, nor does it 
remedy the concerns about facilities' ability to accurately measure 
fenceline EtO concentrations (i.e., there are still no reliable methods 
that can measure to the level of precision required).
     Coupling fenceline monitoring with a canister monitoring 
network and a so-called ``new'' reference method does not transform the 
fenceline monitoring as proposed into a new technology that is within 
the CAA section 112(d)(6) authority.
    Some of these commenters contended that even if the proposed 
fenceline monitoring requirements were within the scope of CAA section 
112(d)(6) authority, the EPA failed to adequately consider/quantify a 
level of emission reduction from the proposed fenceline monitoring and 
did not account for any of the potential costs associated with 
achieving such emission reductions (i.e., the EPA only considered the 
costs of the actual monitoring and not the root cause and corrective 
action requirements). A commenter asserted that had the EPA 
appropriately accounted for costs, it would have concluded that the 
proposed fenceline monitoring requirements are not cost-effective, 
consistent with the Agency's determination for the options

[[Page 42999]]

considered for equipment leaks, PRDs, and storage vessel breathing 
losses. The commenter argued that the EPA failed to quantify the 
additional HAP emissions reductions for EtO and chloroprene that the 
Agency indicates will be required for compliance or to consider the 
cost of these additional reductions (in addition to the cost of the 
required root cause and corrective action analyses) as is required to 
meet the Agency's obligation under CAA section 112(d)(2). The commenter 
stated that the EPA has not assigned emissions reductions of benzene, 
1,3-butadiene, ethylene dichloride, or vinyl chloride as a result of 
implementing the proposed fenceline monitoring work practice 
requirements; and with the exception of EtO and chloroprene, the Agency 
implies that additional reductions beyond those the EPA proposed 
elsewhere in the rulemaking will be unnecessary to meet the fenceline 
action levels. The commenter attested that the EPA proposed additional 
requirements on top of those already required by the existing rules, or 
that will be required as part of the other proposed revisions (e.g., 
the proposed flare standards, the existing and proposed monitoring 
requirements for process vents, and equipment leaks and PRDs), without 
identifying deficiencies in the current and proposed requirements. 
Similarly, other commenters stated that the EPA has not demonstrated 
that fenceline monitoring is necessary to reduce HAP emissions or to 
provide an ample margin of safety; and the lack of emissions reductions 
associated with the proposed requirements shows that such requirements 
are unnecessary to the ultimate goals of CAA section 112.
    Response: We disagree with the commenters' assertion that the 
proposed fenceline monitoring work practice standard is not authorized 
under CAA section 112(d)(6), but we are making certain changes to the 
fenceline monitoring program in the final rule in response to comments, 
including adopting a second action level for just chloroprene under CAA 
section 112(f)(2). Contrary to the commenter's claims, we specifically 
proposed the fenceline monitoring standard under CAA section 112(d)(6) 
to be a work practice standard that is applied broadly to target 
fugitive emissions sources located at HON and P&R I facilities. The 
proposed standard does more than impose monitoring as some commenters 
suggested; it also limits emissions from sources because it requires 
the owner or operator to identify and reduce HAP emissions through a 
monitoring and repair program, as do many work practice standards 
authorized under CAA sections 112(h) and (d). We note that the sources 
addressed by the fenceline monitoring standard--fugitive emissions 
sources such as wastewater collection and treatment operations, 
equipment leaks, heat exchange systems and storage vessels--are already 
subject to work practice standards. Our review of these requirements 
indicates that this fenceline monitoring work practice standard would 
be a further improvement in the way fugitive emissions are managed and 
would, by providing such further assurance of compliance with emission 
standards and work practice standards, also provide an extra measure of 
protection for surrounding communities. Consistent with the criteria in 
CAA section 112(h)(2), we determined and established that work practice 
standards are appropriate for fugitive emissions at the time we 
established the initial MACT standards. Today, we reaffirm that it is 
impracticable to directly measure all fugitive emission sources at a 
given source but do not consider it necessary to reiterate these 
findings as part of this action to add the fenceline monitoring 
provisions for these sources under CAA sections 112(d)(6) and (f)(2). 
We note that the commenters do not provide any grounds to support a 
reevaluation as to whether these fugitive emission sources are 
appropriately regulated by a work practice standard.
    The EPA, in establishing action levels for the fenceline monitoring 
work practice standard, relied on the authority provided in CAA section 
112(d)(6) to set action levels at the highest concentration 
anticipated, considering the emission reductions anticipated under the 
additional standards we are adopting under CAA sections 112(d)(6) and 
112(f)(2). Again, the section 112(d)(6)-based action levels function to 
verify the expected emissions reductions resulting from compliance with 
the final emission standards, and reflect concentration levels that are 
largely already resulting from sources subject to the rules and are 
therefore cost-effective. Further, in the proposal the EPA acknowledged 
that the proposed action levels for EtO and chloroprene of 0.2 ug/
m3 and 0.3 ug/m3, respectively, were lower than 
the fenceline modeled concentrations for EtO and chloroprene from 
facilities in the SOCMI and Neoprene Production source categories after 
implementation of the proposed emission standards, and we took comment 
on whether we should require these lower action levels under CAA 
section 112(f)(2). In this final rule, we believe it is reasonable, 
given the unique circumstances presented by these source categories, to 
require these lower action levels. First, for EtO, the lower action 
level reflects concentrations that all HON-subject facilities, except 
for one, are currently meeting and are therefore cost-effective under 
CAA section 112(d)(6). Second, consistent with the second step of the 
risk review under the Benzene NESHAP approach addressing whole-facility 
risks, for chloroprene the lower action level reflects concentrations 
what will result in whole facility risks from this HAP dropping to 100-
in-1 million. Further whole-facility reductions in EtO and chloroprene 
emissions from other sources located at major source facilities subject 
to these standards, including sources outside the source category, will 
help reduce risks from the whole-facility emissions of EtO and 
chloroprene from facilities with sources in the SOCMI and Neoprene 
Production source categories.
    To reduce risk in the final rule we are making an adjustment from 
what was proposed. First, we are establishing under CAA section 
112(d)(6), for all six of the monitored pollutants, action levels that 
correspond to the fenceline concentrations expected to result from 
compliance with the final rule's standards and work practices 
applicable to HON and P&R I processes and which reflect concentrations 
that HON and P&R I sources are largely already achieving, such that 
these action levels function to provide further assurance of such 
compliance of the emission standards and provide for corrective action 
when action levels are exceeded. For benzene, 1,3-butadiene, ethylene 
dichloride, EtO and vinyl chloride, these are the same action levels as 
proposed. For chloroprene, instead, the action level has been adjusted 
upward to 0.8 ug/m3 (see Docket Item No. EPA-HQ-OAR-2022-
0730-0091, page 24) to reflect the modeled expected fenceline 
concentration resulting from the other final standards and work 
practices chloroprene. This first action level is, therefore, 
consistent with how we established fenceline monitoring requirements 
under CAA section 112(d)(6) in the petroleum refineries NESHAP and how 
we represent the primary CAA section 112(d)(6)-based fenceline 
monitoring program under the final rule.
    Although the EtO action level of 0.2 ug/m3 is lower than 
what the EPA's modeling shows will result from compliance with the 
final CAA section 112(d) and 112(f) SOCMI source category emission 
standards in the final HON, as we discussed in the proposed rule, we 
expect that major sources with

[[Page 43000]]

HON processes will be able to employ additional facility-wide measures, 
including those at other EtO-emitting processes outside of the SOCMI 
source category, to obtain additional cost-effective EtO reductions via 
improvements in maintenance and operations and enable compliance with 
the CAA section 112(d)(6) EtO action level. This is already being 
demonstrated by the fact that all HON-subject facilities, except for 
one, are already showing concentrations at or below the final action 
level. Moreover, this is reasonable due to the integrated nature of 
chemical plant operations, where multiple process units may be subject 
to NESHAP for more than one source category and products of units in 
some categories may also be feedstocks for units in other source 
categories. Accordingly, the source category designations, while part 
of the NESHAP program, are somewhat of an artificial distinction in 
these highly integrated chemical manufacturing facilities. For example, 
there are emission sources that often serve the entire facility, such 
as wastewater treatment systems and heat exchange systems, but they are 
typically assigned to a single source category or subcategory. Because 
of the propensity for large integrated chemical plants to contain 
numerous source categories, and also to contain units that span 
multiple source categories, we are finalizing fenceline work practice 
standards with an EtO action level that relies on achieving reductions 
across the whole HON facility, even if that includes non-HON EtO-
emitting processes.
    Second, in light of the very high risk presented by chloroprene 
emissions, we have concluded it is appropriate, in addition to adopting 
the primary CAA section 112(d)(6)-based action levels and monitoring 
program for all six subject HAP, to supplement the program with a 
secondary action level for this pollutant. This secondary action level, 
equivalent to that proposed, reflects fenceline concentrations for this 
pollutant that increase the margin of safety and advances the 
objectives of CAA section 112(f)(2). Although our modeling indicates 
that compliance with the other emission standards and work practices 
promulgated for Neoprene Production sources may not produce this 
secondary level, we anticipate--as explained in the proposal--that 
major sources will be able to employ additional facility-wide measures, 
such as maintenance measures, to achieve further chloroprene reductions 
to reach this secondary, CAA section 112(f)-based action level.
    In the case of chloroprene emitted by the Denka Performance 
Elastomer, LLC facility (subject to both the P&R I NESHAP and the HON), 
we do not anticipate taking further source-category-wide rulemaking 
action that could re-set CAA section 112(d)(6)-based lower action 
levels to reflect future additional chloroprene reductions from 
additional source category processes. Consequently, for Denka 
Performance Elastomer, LLC's chloroprene emissions, this rulemaking is 
the final opportunity for us to establish an action level with the goal 
of assuring that whole-facility chloroprene emissions are reduced to a 
level that provides an ample margin of safety to protect public 
health.\50\ This is consistent with the statute because under the CAA 
section 112(f)(2) ample margin of safety second step, the Benzene 
NESHAP approach that is incorporated into the CAA allows the EPA to 
consider quantified or unquantified health effects, effects due to co-
location of facilities, and co-emission of pollutants.
---------------------------------------------------------------------------

    \50\ See footnote 47.
---------------------------------------------------------------------------

    We disagree that the fenceline monitoring standards we are 
finalizing in this rule are redundant with MACT emissions standards for 
fugitive HAP emissions sources. The MACT standards impose requirements 
on fugitive HAP emissions sources consistent with the requirements in 
CAA section 112(d)(2) and (3), and the fenceline monitoring requirement 
is not a replacement for those requirements. Rather, based on our 
review of these standards, we concluded that the primary CAA section 
112(d)(6)-based fenceline monitoring program is a development in 
practices, processes or control technologies that is a necessary 
revision to the previous standard, as it would improve management of 
fugitive emissions in a cost-effective manner and help assure 
compliance with applicable process emission standards under the HON and 
the P&R I NESHAP. Requiring sources to establish a fenceline monitoring 
program that identifies HAP emission sources that cause elevated 
pollutant concentrations at the fenceline, and correcting high 
emissions through a more focused effort, augments but does not replace 
the existing requirements. We found that, through early identification 
of significant fugitive HAP releases through fenceline monitoring, 
compliance with the Refinery MACT fenceline work practice standard for 
these similar emissions sources in these source categories has resulted 
in a significant reduction in benzene emissions. The action levels for 
the primary fenceline work practice standard, by contrast, are not 
based on the best performers but rather on the highest value expected 
on the fenceline from any source, based largely on the modeling of 
emission inventories expected to result from compliance with the final 
emission standards and work practices under the rules.
    Lastly, we acknowledge commenters' support for fenceline 
monitoring. However, with respect to the commenter requesting that a 
third party be required to monitor the fenceline concentrations, the 
EPA disagrees. Fenceline monitoring requires a level of access to the 
facility and measurement devices that would be burdensome to 
accommodate for facilities. Fenceline monitoring is intended to address 
concerns with underreported emission inventories and works based on 
timely root cause analysis. Adding a third-party requirement would slow 
a facility's ability to respond to fugitive emissions in a timely 
manner.
    Comment: A commenter argued that fenceline monitoring is not an 
emissions standard or work practice within the meaning of CAA section 
112. Citing CAA section 302(k), the commenter said that, by itself, 
fenceline monitoring does not reduce emissions, rather all that 
fenceline monitoring does is identify ambient concentrations of a 
specific chemical; it does not even identify whether the chemical is 
from a regulated source, let alone identify a specific regulated unit 
at such source. The commenter said that fenceline monitoring can only 
potentially reduce emissions when coupled with additional requirements, 
but, at least in this instance, the EPA does not appear to claim 
associated reductions from the source category. The commenter added 
that while the EPA is proposing ``action levels,'' again, these levels 
alone do not ``limit the quantity, rate, or concentration of 
emissions.'' The commenter said that according to the preamble, if the 
emissions inventories are accurate, ``all facilities should be able to 
meet the fenceline concentration action levels considering the controls 
[EPA is] proposing''; therefore, even when coupled with action levels, 
the EPA's proposal does not claim that fenceline monitoring will result 
in any meaningful emissions reductions from the source category. The 
commenter also stated that while exceedance of an action level may 
trigger further requirements, the action level does not, by itself or 
combined with fenceline monitoring, limit emissions--additional actions 
are required; and, because the

[[Page 43001]]

EPA's proposal measures ambient concentrations, an exceedance of a 
proposed action level is not necessarily the result of emissions from 
the facility in question or from an exceedance of a standard.
    The commenter noted that while the EPA states that it is proposing 
fenceline monitoring as a work practice standard, which could fall 
within the meaning of ``any design, equipment, work practice or 
operational standard promulgated under [the CAA],'' the EPA does not 
explain how fenceline monitoring meets the requirements for a work 
practice standard. The commenter added that work practice standards are 
authorized only in limited circumstances under CAA section 112(h)(1) 
when it is not feasible to prescribe or enforce an emission standard 
for control of HAPs, and the EPA has not adequately explained what 
elements of the proposal are work practice standards.
    Response: Section 112(d)(6) of the CAA requires the EPA to review 
and revise the MACT standards, as necessary, taking into account 
developments in ``practices, processes and control technologies.'' 
Consistent with our long standing practice for the technology review of 
MACT standards, in section II.G.1 of the proposal preamble, we list 
five types of ``developments'' we consider.
    Fenceline monitoring fits squarely within two of those five types 
of developments (emphasis added):
     Any add-on control technology or other equipment that was 
not identified and considered during development of the original MACT 
standards.
     Any work practice or operational procedure that was not 
identified or considered during development of the original MACT 
standards.
    As used here, ``other equipment'' is clearly separate from and in 
addition to ``add-on control'' technology and is broad enough to 
include monitoring equipment. In this case, fenceline monitoring 
includes equipment that we did not identify and consider during 
development of the original MACT standards. Additionally, the primary 
fenceline standard is a work practice standard, involving monitoring, 
root cause analysis, and corrective action not identified at the time 
of the original MACT standards. Therefore, the primary fenceline 
requirements are a development in practices that will improve how 
facilities manage fugitive emissions, and the EPA appropriately relied 
on CAA section 112(d)(6) in requiring this standard. (Note: The EPA is 
not relying on CAA section 112(f)(2) as the basis for the primary 
fenceline monitoring work practice standard established under section 
112(d)(6) for benzene, butadiene, vinyl chloride, ethylene dichloride, 
chloroprene, and EtO, and has set action levels according to the annual 
average concentrations modeled at the facility fenceline for any 
facility after compliance with process unit emission standards 
applicable to HON and P&R I sources and that reflect levels sources are 
largely already achieving. However, as discussed elsewhere in this 
section of the preamble, we are also setting a secondary action level 
of 0.3 ug/m\3\ for chloroprene under CAA section 112(f)(2), because 
this standard will further reduce risks from the whole-facilities 
consistent with the goal to provide an ample margin of safety to 
protect public health).
    Comment: A commenter argued that the EPA's explanation for the 
basis of selecting the six compounds for fenceline monitoring is 
inadequate when compared against the rulemaking record. The commenter 
said that the EPA appears to base its selection of compounds on 
previous and current risk drivers because the EPA indicates that 
``[s]everal of these compounds were identified as cancer risk drivers 
in the prior risk and technology reviews for the HON and P&R I NESHAP 
conducted in 2006 (HON) and 2008 and 2011 (P&R I). . ..'' The commenter 
contended that, with the exception of EtO, the maximum risk previously 
found by the EPA in its reviews for the HON and P&R I NESHAP were well 
below 100-in-1 million (or not identified as a risk driver at all); the 
commenter provided a table showing the EPA's determinations of 2006 
HON, 2008 P&R I and 2011 P&R I MIR for benzene, 1,3-butadiene, 
chloroprene, EtO, ethylene dichloride, and vinyl chloride. The 
commenter pointed out that in each of these previous assessments, the 
EPA found risks acceptable and did not adopt additional standards to 
address residual risk or to ensure an ample margin of safety. The 
commenter said the EPA also did not identify benzene, 1,3-butadiene, 
ethylene dichloride, or vinyl chloride as driving unacceptable risk 
under the current assessment; thus, while the EPA's selection of 
benzene, 1,3-butadiene, ethylene dichloride, and vinyl chloride based 
on risk is questionable under the EPA's framing of the option as part 
of its CAA section 112(d)(6) technology review, a closer inspection of 
the EPA's previous risk assessments indicates that in fact, these 
compounds did not drive any unacceptable risk. The commenter stated 
that the EPA's proposal to require millions of dollars of monitoring 
for no emissions reductions is unjustified under CAA section 112(d)(6) 
and unnecessary under CAA section 112(f). The commenter added that they 
acknowledge that the EPA found EtO and chloroprene to be risk drivers 
as part of their voluntary assessment supporting this proposed 
rulemaking and are claiming unquantified emissions reductions as a 
result of implementing fenceline monitoring; however, according to the 
commenter, the Agency determined that these additional reductions are 
unnecessary under CAA section 112(f) when it proposed to find 
acceptable risk and an ample margin of safety after implementation of 
the controls detailed in section III.B.2.a of the proposal preamble (88 
FR 25080, April 25, 2023).
    The commenter argued that it would be inappropriate to consider 
fenceline monitoring in context of the CAA section 112(f) review. The 
commenter stated that the EPA has already concluded that the controls 
that it has proposed to impose protect human health and the environment 
with an ample margin of safety. The commenter added that the EPA has 
not identified any additional emission reductions from the source 
category that would be necessary to reduce risk from the source 
category and that the EPA has failed to demonstrate that any such 
controls are cost-effective, which would be included as any ample of 
safety analysis. The commenter also said that the action level is not 
tied in a meaningful way to reducing risk to an acceptable level.
    Response: The EPA implemented a fenceline monitoring standard to 
address emissions of pollutants that it determined could cause 
unacceptable risk, based on risk modeling of emission inventories and 
accounting for the range of uncertainty associated with these 
estimates. When the EPA promulgated the Refinery MACT fenceline work 
practice standard, the EPA acknowledged that emissions of benzene and 
indeed, of all other HAP in the source category, did not pose 
unacceptable risk when emissions from refineries were modeled, but that 
the work practice standard was put in place to address the uncertainty 
associated with emission estimates from fugitive sources and to 
preserve the decisions regarding the findings of acceptable risk and 
ample margin of safety (79 FR 36290, June 30, 2014). The same 
uncertainty exists here for the SOCMI and P&R I source categories. As 
explained in the April 25, 2023 proposal, we collected fenceline 
measurements in addition to modeling inventories, and our fenceline 
measurements indicate that

[[Page 43002]]

concentrations at the fenceline almost always exceed modeled 
concentrations, indicating the potential for significant uncertainty 
with regard to our risk analysis and findings of acceptable risk. As 
discussed earlier in this document, the EPA is not relying on CAA 
section 112(f)(2) as the basis for the primary fenceline monitoring 
work practice standard established under CAA section 112(d)(6) for 
benzene, butadiene, vinyl chloride, ethylene dichloride, chloroprene, 
and EtO and has set action levels according to the annual average 
concentrations modeled at the facility fenceline for any facility after 
compliance with process unit emission standards applicable to HON and 
P&R I sources and that are reflective of concentrations subject sources 
are already achieving. Further, we disagree with the commenters who 
suggest that the EPA may not require fenceline monitoring pursuant to 
CAA section 112(d)(6) because the EPA has not determined that fenceline 
monitoring is necessary to ensure an acceptable level of risk or to 
provide an ample margin of safety. CAA section 112(d)(6) does not 
require the EPA to factor in the health considerations provided in CAA 
section 112(f)(2) when making a determination whether it is 
``necessary'' to revise the previous emission standard.
    For chloroprene, we are finalizing in the primary CAA section 
112(d)(6)-based program the action level of 0.8 ug/m\3\ that reflects 
compliance with the source category-specific emissions limits for the 
Neoprene Production source category in the P&R I NESHAP. Separately, we 
are also setting a secondary action level of 0.3 ug/m\3\ for 
chloroprene under CAA section 112(f)(2), because this standard further 
reduces from the whole-facility risk from sources emitting chloroprene 
to levels that are consistent with the goals of CAA section 112(f)(2). 
As discussed earlier, in the proposal, we acknowledged that the 
proposed action level of 0.3 ug/m\3\ for chloroprene is lower than the 
fenceline modeled concentrations from facilities in the Neoprene 
Production source category after implementation of our proposed 
standards under CAA section 112(f)(2); however, considering whole-
facility risks, and in light of the configuration of the emission 
sources subject to these rules that contribute to whole-facility risk 
that remain for the impacted communities after the imposition of 
controls, we are setting the additional second action level for 
chloroprene at facility boundaries as low as possible (considering 
method detection limitations) to ensure that the emission reductions 
anticipated from implementation of controls used to meet the proposed 
standards and to achieve additional chloroprene emission reductions are 
achievable. Reductions to achieve this action level will likely come 
from controlling additional emission sources at the one Neoprene 
Production facility that might not be considered part of the source 
category. Controlling these sources reduces emissions from the entire 
facility, not just the source category, and makes it possible for 
operators to achieve the lower action level. Thus, in this final rule, 
and based on the unique circumstances presented here, we consider 
facility-wide risk as an additional factor we may consider under CAA 
section 112(f)(2) and, in addition to the primary CAA section 
112(d)(6)-based fenceline monitoring program addressing all six subject 
HAP, we are promulgating a separate and secondary lower action levels 
for just chloroprene under CAA section 112(f)(2).
    Comment: Many commenters requested that the EPA expand the 
fenceline monitoring requirements to every facility in the SOCMI, P&R 
I, and P&R II source categories so owners and operators of these 
facilities can demonstrate, by representative monitoring data, that 
pollution from these facilities poses minimal levels of harm to 
fenceline communities. Some of these commenters pointed out that, as 
proposed, only about 60 percent of the facilities in these source 
categories would have to conduct fenceline monitoring. Other commenters 
contended that, as proposed, 90 facilities would have no fenceline 
monitoring requirements. A commenter contended that there is no reason 
or need for the EPA to have selected just six toxic pollutants and used 
them as basis to omit facilities from fenceline monitoring, given that 
CAA section 112(d)(6) requires making any changes that are 
``necessary'' to bring standards into full compliance with the CAA, 
such as setting limits on uncontrolled and inadequately controlled 
emissions. The commenter pointed out that the EPA set fenceline 
monitoring requirements that applied to all refineries subject to 
NESHAP subpart CC and did not omit sources based on the selected 
constituents to be monitored.
    Some commenters suggested that the EPA could add more toxic 
pollutants to its current list of six fenceline monitoring 
constituents, in order to ensure that each facility has at least one or 
more sentinel chemicals that can be monitored. A commenter recommended 
that the EPA include benzene, toluene, ethylbenzene, and xylenes 
(BTEX), methanol, and formaldehyde constituents to the list of 
pollutants requiring fenceline monitoring. The commenter pointed out 
that based on TRI data, the inclusion of formaldehyde to the list of 
pollutants requiring fenceline monitoring would add another 28 
facilities, the inclusion of methanol would add another 13 facilities, 
and the inclusion of BTEX/n-hexane would add another 3 facilities. The 
commenter also pointed out that it is no surprise that information 
gathered from only HON and P&R I sources resulted in constituents most 
representative of those sources and not representative of P&R II 
sources; and had the EPA included P&R II data in the information it 
gathered for the purpose of fenceline monitoring constituents, the EPA 
would have found that all five P&R II sources emit epichlorohydrin and 
that several of them emit the non-benzene BTEX constituents. Commenters 
requested that the EPA add formaldehyde to the list of pollutants 
requiring fenceline monitoring because the IRIS data indicates that as 
a carcinogen, formaldehyde is even more potent than benzene. A 
commenter said evidence from emission reports suggests that some 
facilities may be underreporting or only sporadically reporting 
formaldehyde emissions (e.g., the Conoco-Phillips/Shell Wood River 
manufacturing site in Illinois reported very large formaldehyde 
emissions to the NEI in 2017 and even larger amounts to the 2020 NEI 
but has not disclosed formaldehyde emissions in any of the TRI reports 
for the facility for the 5 years between 2017 and 2020). A commenter 
recommended that the EPA require each facility to select the 
constituents to be monitored via tailored fenceline monitoring plans 
that are specific to each facility's emissions and risk drivers. 
Additionally, at least one commenter said they hope that EPA will 
replicate this multi-pollutant monitoring in other rules, including as 
a supplement to the ethylene production rules.
    On the contrary, some commenters argued that the proposed fenceline 
monitoring requirements would impermissibly regulate emissions from 
non-HON sources. Citing the proposal at 88 FR 25145-46, some of these 
commenters pointed out that the EPA expressly notes that facilities are 
not permitted to exclude non-HON sources of the target pollutants that 
are within facility property boundaries when determining whether 
monitored concentrations exceed action levels. The commenters said that 
regulating emissions from sources outside of the

[[Page 43003]]

source category is incompatible with the EPA's statutory mandate to 
``review and revise'' the ``emissions standards promulgated under this 
section,'' which refers to the source-category MACT standards 
promulgated under CAA section 112(d). The commenters stated that the 
EPA may only regulate HON sources under its technology review authority 
in accordance with the statutory language and structure of the CAA. The 
commenters reiterated that when enacting CAA section 112, Congress 
instructed the EPA to promulgate a list of specific source categories 
and that Congress then instructed the EPA to establish emission 
standards ``[f]or the categories and subcategories the Administrator 
lists under subsection (d)'' of CAA section 112. At least one of these 
commenters cited CAA sections 112(c), (d)(1), (d)(3)(A), (d)(6), and 
(f) as examples of how the CAA authorizes the EPA to impose emissions 
standards only on particular source categories or subcategories. The 
commenter asserted that none of these provisions expressly authorize or 
reasonably can be construed to allow the EPA to develop and impose an 
emissions standard that applies across multiple source categories. The 
commenter contended that for this reason, the EPA's proposal to apply 
fenceline monitoring to site-wide emissions, including emissions from 
source categories beyond the SOCMI source categories addressed in this 
rulemaking, is legally unfounded; and if the EPA decides to impose a 
fenceline monitoring program in the final rule, it must be limited such 
that it applies only to emissions from particular source categories. 
Other commenters said they were concerned that the proposed approach 
results in the EPA's establishing the emission point as the facility 
boundary, thereby expanding the definition of an affected source. The 
commenters provided an example saying that the proposed rule does not 
contain provisions that would exclude a site from fenceline monitoring 
for benzene due to the presence of a gasoline storage tank onsite that 
is used to refuel mobile equipment and is not even part of the HON 
process.
    Some of the commenters stated that the imposition of fenceline 
monitoring requirements to non-HON sources is unreasonable, arbitrary, 
and capricious. One of these commenters said the EPA is conducting the 
technology review for the SOCMI category and not for other collocated 
categories; and despite this, the EPA is using this action as a vehicle 
to impose requirements on other source categories through the HON 
rather than evaluating such controls in the context of the applicable 
CAA section 112 standard. The commenter asserted that such use of a 
source-specific technology review to promulgate requirements that 
affect an unknown number of other source categories is arbitrary and 
capricious and circumvents statutory design. The commenter added that 
the EPA has not assessed the cost that would fall on other source 
categories and that the EPA's proposal failed to properly provide 
notice or provide a meaningful opportunity to comment to all interested 
stakeholders.
    Some commenters said that they support the EPA's proposal to allow 
facilities to account for offsite, upwind sources through the use of 
near-field source correction under 40 CFR 63.184(g); however, these 
commenters said they disagree with the EPA's assertion that this option 
should not be provided for onsite, non-source category emissions. These 
commenters asserted that the EPA cannot regulate sources beyond those 
subject to the technology review; thus, the commenters said, the EPA 
should add provisions in the final rule similar to those at 40 CFR 
63.658(i) from the 2015 Petroleum Refinery Sector Rule to address 
onsite sources that are not part of the affected source under the HON 
and P&R I NESHAP. However, at least one commenter objected to adding 
provisions in the final rule similar to those at 40 CFR 63.658(i) and 
stated that inclusion of facility-wide emissions in the action level is 
appropriate because it will support the control of toxic air pollutants 
emitted from all sources within the facility, all of which affect 
fenceline communities, and also avoids the development of complex and 
uncertain processes to attribute emissions from collocated sources and 
equipment that may be used in processes associated with multiple source 
categories. This commenter pointed out that only a small number of 
refineries (13) have approved site-specific monitoring plans, and only 
five of those plans include procedures for excluding onsite sources 
owned by the refinery but that do not fall within the refinery source 
category.
    Another commenter provided a real-life example of the difficulty of 
dealing with onsite, non-source category emissions where Facility A, 
which is subject to the HON, owns and operates an Industrial Site that 
supplies services to other tenants, including wastewater treatment. The 
commenter said that Facility A does not use, produce, or emit EtO from 
any of its own processes; however, two tenants--Facility B and Facility 
C--are located inside the Industrial Site, and both emit EtO (and 
Facilities B and C are not subject to the HON but are subject to 40 CFR 
63, subpart PPP). The commenter said that Facilities B and C send 
miniscule liquid EtO emissions to the WWTP for disposal; and reported 
emissions by Facility A of EtO from their WWTP, since taking over the 
Industrial Site, are less than 1 lb/yr. Using this example, the 
commenter contested that it is inappropriate to require Facility A to 
perform EtO fenceline monitoring and conduct a root cause analysis with 
subsequent corrective action because Facility A does not use, store, or 
emit EtO from any of their own production processes (i.e., Facility A 
only has EtO wastewater emissions from treating EtO wastewater from 
Facility B and Facility C as the site owner). The commenter made the 
following additional points: (1) The amount of EtO emitted to the air 
from wastewater obtained and treated by other facilities from Facility 
A has been less than a pound for the past 3 years; (2) the WWTP is 
located outside the fenceline of the Industrial Site; (3) Facility A 
does not have the authority to perform root cause analysis or 
corrective actions on facilities they do not have operational control 
over; and (4) if action level concentrations are found, it is not 
possible to determine whether the EtO comes from Facility B and/or 
Facility C, nor their individual contributions. For the Facility A 
WWTP, there is not a logical corrective action for emissions of less 
than 1 lb/yr that would change the EtO concentrations found in the 
ambient air. Other commenters provided similar examples and expressed 
similar concerns.
    Response: The EPA considered the potential applicability of 
fenceline monitoring as part of this proposed technology review. 
Generally, the EPA has found fenceline monitoring to be an effective 
tool when fugitive or ground-level releases are significant or where we 
have identified considerable uncertainties in HAP emissions estimates 
from fugitive emission sources such that they affect our decisions 
relative to whether there exists residual risk, for example. Other 
considerations include the types of pollutants that are emitted, the 
availability of fenceline monitoring measurement methods for the key 
pollutants, proximity of residences or other areas where people could 
be exposed to emissions at or near facility fencelines, and the other 
types of monitoring that are already required or are being considered.
    Regarding the question of including onsite, non-source category 
emissions in the fenceline monitoring work practice standard, we 
proposed not to allow

[[Page 43004]]

corrections to monitoring for onsite non-source category sources, as 
they were included in emissions sources modeled to develop the action 
levels. In other words, the action levels in the primary fenceline 
monitoring program are based on expected facility-wide emissions and 
account for contributions from these non-source category sources. For 
more details, see the document titled Clean Air Act Section 112(d)(6) 
Technology Review for Fenceline Monitoring located in the SOCMI Source 
Category that are Associated with Processes Subject to HON and for 
Fenceline Monitoring that are Associated with Processes Subject to 
Group I Polymers and Resins NESHAP (Docket Item No. EPA-HQ-OAR-2022-
0730-0091) and the residual risk technical support document titled 
Residual Risk Assessment for the SOCMI Source Category in Support of 
the 2023 Risk and Technology Review Proposed Rule (Docket Item No. EPA-
HQ-OAR-2022-0730-0085). The secondary action level for chloroprene 
adopted under CAA section 112(f)(2) appropriately anticipates the need 
for additional reductions of this pollutant in order to further the 
goal to protect public health from whole-facility chloroprene 
emissions. Further, in most cases, sources with HON or P&R I source 
categories also account for a significant portion of the action level 
at the fenceline such that the option to attribute and correct monitors 
for emissions from collocated sources and equipment that may be used in 
processes associated with multiple source categories becomes a very 
complex and unnecessary process. In the Petroleum Refinery example, we 
note that the option to correct monitors for non-source category 
sources within the fenceline was found to be very difficult to 
implement practically and that the option was subsequently removed from 
most site-specific monitoring plans.
    We agree that the circumstance described by the commenter, although 
uncommon, might result in a situation where the most significant 
contribution would not be from the portions of the facility that are 
subject to the process limits established for the HON or P&R I source 
itself. In this case we would apply the requirements based on how the 
source has been defined for the purposes of applicability of CAA 
section 112 standards, which is any stationary source or group of 
stationary sources located within a contiguous area and under common 
control. The commenter indicates that these facilities are not under 
common control, therefore Facility A would have to conduct fenceline 
monitoring because it does use, produce, and emit EtO, and it is 
subject to the HON, as the commenter indicates that it treats 
wastewater from Facilities B and C in its wastewater treatment process. 
In this case, Facility A could correct monitoring readings for offsite 
impacts using a site-specific monitoring plan. Depending on the 
orientation of Facilities B and C, this approach would require real-
time monitoring of portions of the fenceline bordering Facilities B 
and/or C and is allowed by the proposed and final rule (see 40 CFR 
63.184(g)). The commenter presumes that the amount of EtO emitted by 
the treatment process is miniscule, but that is precisely the question 
that fenceline monitoring is envisioned to address and to ensure that 
emissions are maintained at low levels. We believe even in this 
situation, the fenceline monitoring standard is reasonable and provides 
for an approach to address the commenter's concerns. Further, we reject 
the notion that our proposal failed to properly provide notice or to 
provide a meaningful opportunity to comment for all interested 
stakeholders. The major source to which these standards apply is by 
definition under common control. Unless the sources are subject to the 
HON and P&R I standards, there is no requirement for operators of other 
source categories to comply with these requirements. Therefore, we 
reject the notion that this proposal is arbitrary and capricious and 
circumvents statutory design.
    Comment: With regard to the EPA's proposed fenceline monitoring 
requirements, numerous commenters contended that background 
concentrations need to be accounted for when calculating the 
incremental contributions from EtO-emitting facilities. A commenter 
said that without understanding the significance of high ambient 
background levels, it is not possible to determine a facility's true 
impact on ambient concentrations above the background level or the risk 
of EtO exposure. This commenter added that implementation of fenceline 
monitoring when background is unknown has the potential to generate 
data that will not represent what is intended, will require follow up 
action to correct problems that do not exist, and has the potential to 
frighten communities near facilities in the absence of elevated risk. 
Similarly, other commenters asserted that facilities are likely to show 
exceedances attributable not only to their own emissions, but also from 
background levels of EtO and emissions of EtO sources from offsite 
sources. These commenters said that background concentrations threaten 
a potentially endless cycle of investigations for the source of 
emissions which are beyond the EPA's regulatory authority or the 
facility's control; and the proposed fenceline monitoring requirements 
improperly attempt to turn facilities into mini ambient air quality 
regulators, requiring them to investigate and analyze fenceline 
exceedances that could be caused by another facility, background EtO 
levels, or simply an error in sampling due to the inability to 
accurately measure EtO at the incredibly low levels proposed.
    Some of these commenters acknowledged that the EPA's proposed 
sampling protocol attempts to address background concentrations by 
taking the highest sample and subtracting the lowest sample from it; 
however, these commenters said it is not clear how the proposed 
protocol fully addresses background concentrations and other questions 
that remain regarding high background concentrations that have been 
present in sampling conducted by other states, including at National 
Air Toxic Trends Station (NATTS) sites. These commenters as well as 
others said that background monitors in many cases show higher 
concentrations than monitors located within or nearby EtO-emitting 
facilities. Some of these commenters provided additional information 
about background EtO concentration data available from two studies 
conducted by state agencies:
     A 2022 study conducted by the Georgia Department of 
Natural Resources, Environmental Protection Division titled ``Ethylene 
Oxide Monitoring Report'' included EtO monitors near known emitters in 
addition to areas designated as ``background'' locations away from any 
known emitters of EtO. The 2020 concentration data for one of the 
background monitors located in South DeKalb showed that background 
concentrations ranged from a low of 0.10 [mu]g/m3 to a high 
of 3.7 [mu]g/m3 and that the monthly difference between the 
highest and lowest reported concentration value ranged from 0.22 [mu]g/
m3 to 3.2 [mu]g/m3, with an average monthly 
difference of 0.88 [mu]g/m3.
     A 2022 study conducted by the West Virginia Department of 
Environmental Protection in the Kanawha Valley, collecting background 
concentration data in Guthrie and Buffalo, West Virginia, revealed that 
EtO background measurements were made in Guthrie that ranged from 0.059 
[mu]g/m3 to 1.74 [mu]g/m3 and in Buffalo that ranged from 
0.20 [micro]g/m3 to 1.31 [micro]g/m3.

[[Page 43005]]

    Commenters claimed that the reports published by the Georgia 
Department of Natural Resources, Environmental Protection Division, and 
by the West Virginia Department of Environmental Protection indicate 
that background concentrations of EtO can vary significantly, including 
up to more than an order of magnitude greater than EPA's proposed 
action level of 0.20 [mu]g/m3. Other commenters noted that 
the EPA's AirToxScreen presents EtO background levels as zero (so risks 
associated with background levels of EtO are not included in 
AirToxScreen maps and reports); however, according to commenters, this 
is highly unlikely to be the case, as shown by data in the EPA's NATTS 
sites, which are designed to be representative of community air toxics 
concentrations. Another commenter cited the West Virginia final report 
titled ``Ethylene Oxide Monitoring--Characterization of South 
Charleston and Institute, West Virginia and Surrounding Areas February 
21, 2023'' and made the following observations of the measured EtO 
background concentrations from year 2018 through November 2021 at 
various monitoring points across the United States:
     There is not even a single data point below the EPA's 100-
in-1 million threshold of 0.01 parts per billion by volume (ppbv).
     The average concentration is 0.122 ppbv which is 12 times 
higher than the EPA's 100-in-1 million threshold of 0.01 ppbv.
     Several monitoring sites have an annual average 
concentration of 0.15 ppbv (0.27 ug/m3 or higher).
     Many of these values are measured at sites that are not 
close to industrial sites where EtO is manufactured or used, thus 
further calling into question whether the EPA really has the correct 
residual risk value.
    Citing the EPA produced document titled ``EPA's Work to Understand 
Background Levels of Ethylene Oxide'' (most recently updated in October 
2021), another commenter presented the following questions that they 
claimed to be unanswered: (1) Is EtO in use by unpermitted sites that 
are causing these levels?; (2) is EtO coming from other activities/
sources such as mobile sources, biogenic sources?; and (3) when the 
IRIS inhalation URE value was developed, did the analysis include 
consideration of the background dosing?
    Response: We disagree with the commenters' assertions that 
background concentrations of EtO are not accounted for in the proposed 
fenceline monitoring provisions. The primary driving force for 
determining when a facility must initiate root cause analysis is the 
annual average [Delta]c value; a root cause analysis is required 
whenever the annual average [Delta]c value is higher than the action 
level. For EtO, the annual average [Delta]c is the average of the most 
recent 73 individual sampling period [Delta]c measurements. The 
sampling period [Delta]c is calculated as the sampling period's highest 
sample result minus the sampling period's lowest sample result. If 
background EtO levels are persistent in the area, this will be captured 
by both the high and low concentration measurements used to develop the 
[Delta]c values and the subtraction will result in only the facility's 
contributions to the EtO concentrations at the fenceline. As such, 
background levels are accounted for in the determination of each 
sampling period's [Delta]c value, and subsequently the annual average 
[Delta]c value.
    If, as commenters indicate, background EtO levels are inconsistent, 
the annual average [Delta]c value must still shift above the action 
level before root cause analysis must be performed. The power of a 
single [Delta]c value to cause undue root cause analysis is mitigated 
when it is averaged with the other measurements. Single events where 
background EtO levels are elevated will be insufficient to cause the 
annual average [Delta]c to exceed the action level. If a single 
[Delta]c value is large enough to skew the annual average derived from 
72 other datapoints above the action level, the EPA expects that an 
emission event occurred and root cause analysis is appropriate.
    Lastly, with respect to commenters' concerns that offsite 
facilities may contribute to EtO measurements at their facility, we 
note that owners and operators may submit site-specific monitoring 
plans to subtract background EtO concentrations from upwind emitters 
from impacted monitors pursuant to 40 CFR 63.184(g)(1) through (4).
    The questions posed by the commenter about unpermitted sites 
emitting EtO or whether unknown sources are developing EtO are out of 
scope for this rulemaking. Section IV.A.3.a of this preamble addresses 
the EtO IRIS URE value.
    Comment: Several commenters requested that the EPA clarify that 
very small amounts of the six compounds (i.e., benzene, 1,3-butadiene, 
chloroprene, ethylene dichloride, EtO, and vinyl chloride) that may be 
produced, used, or stored at trace levels, as incidental by-products, 
and as impurities, should not trigger long-term fenceline monitoring 
requirements. Some of these commenters contended that the proposed 
applicability is unjustifiably broad, rendering it arbitrary and 
capricious. The commenters requested that the EPA provide a de minimis 
level that would trigger fenceline monitoring requirements; and several 
of the commenters also requested that the applicability be limited to 
regulated HON CMPUs. Some of the commenters requested that the EPA 
create exclusions for predetermined de minimis activities such as: 
housekeeping or building maintenance, lab and research activities, 
combustion emissions, transportation emissions, and incidental by-
products or impurities. Similarly, a commenter asserted that the EPA 
uses the phrase ``use, emit, or process'' without any other criteria or 
definition of what this language means.
    A commenter pointed out that according to the EPA's AP-42 
Compilation of Air Emission Factors, the combustion of fuels is likely 
to generate emissions of benzene and 1,3-butadiene (see AP-42, Tables 
1.3-9, 1.4-3, 3.1-3, 3.3-2, and 3.4-3). The commenter added that since 
nearly all HON and NSPS III/NNN/RRR sources are expected to contain 
natural gas piping, and natural gas contains benzene, and the 
applicability of the fenceline monitoring requirement is based on site 
emissions, it is reasonable to conclude that nearly all HON and NSPS 
III/NNN/RRR sites are expected to be subject to the fenceline 
monitoring requirement regardless of whether the SOCMI processes at the 
site emit benzene or 1,3-butadiene. Another commenter said that 
implementing a fenceline monitoring program for any by-product/impurity 
that is intentionally minimized by the owner or operator is not cost-
effective or environmentally beneficial, and as such, warrants 
additional consideration. The commenter stated that chloroprene is a 
by-product/impurity produced in their vinyl chloride monomer production 
process and would be emitted at much lower quantities than ethylene 
dichloride or vinyl chloride; and as described in the HON RTR Proposal, 
if the purpose of the fenceline program is to determine equipment 
leaks, the leaks would be more readily detected with vinyl chloride 
monomer or ethylene dichloride rather than through monitoring for a 
contaminant that may or may not be present in the process fluid.
    Commenters suggested that to avoid trace levels of these compounds 
triggering the monitoring programs, the EPA should establish additional 
applicability criteria for triggering the monitoring requirements given 
that the proposed fenceline air monitoring

[[Page 43006]]

provisions are complex, take significant time to implement, and appear 
to be required for an infinite period. The commenters said the economic 
burden for fenceline monitoring is not justified for facilities with 
low levels of emissions (below de minimis thresholds) for any proposed 
fenceline compound. Some of these commenters recommended that the EPA 
clarify that when the EPA uses the phrase ``if the site uses, produces, 
stores, or emits'' one of the covered chemicals, this means that 
greater than 25,000 lb/yr of a chemical must be used, produced, or 
stored in HON CMPUs at the source. Commenters added that in order to 
trigger fenceline monitoring, the air emissions for a covered chemical 
should also be greater than 1 tpy (~ 0.23 lb/hr annual average) from 
HON CMPUs at the source. Commenters said that the rationale for using 
25,000 lb/yr aligns with other EPA regulations such as 40 CFR 372.25(a) 
which is threshold for reporting of air emissions under the EPA's 
Superfund Amendments and Reauthorization Act Section 313 program; and a 
1 tpy emission threshold (<0.25 lb/hr) is a low threshold for then 
triggering the fenceline air monitoring program. Another commenter said 
that, given that the Agency selected the fenceline action levels by 
modeling emissions from the post-control emissions file in the residual 
risk assessment and selecting the maximum annual average fenceline 
concentration, one potential option for adopting a trigger threshold 
for fenceline monitoring would be to set emission thresholds at 50 
percent of the source category emissions for the facilities that were 
used to set the proposed action level. The commenter said that this 
approach should also be applied for EtO and chloroprene because the 
Agency proposed to find acceptable risk and an ample margin of safety 
for these pollutants after implementation of the controls, thus making 
additional reductions of EtO and chloroprene unnecessary and 
unsupported by any rulemaking authority.
    A commenter suggested that if the EPA does not establish de minimis 
applicability thresholds, then the final rule should include a 
provision that allows for fenceline monitoring to be discontinued at a 
site after 2 years of non-detect fenceline monitoring concentrations 
for a compound. The commenter said that a site with non-detect 
fenceline concentrations does not drive the risk assessment for that 
compound.
    Response: The EPA disagrees with commenters that the fenceline 
monitoring provisions are unjustly broad. Per 40 CFR 63.184, the 
fenceline monitoring provisions are applicable ``for each source as 
defined in Sec.  63.101, and for each source as defined in Sec.  
63.191.'' The definitions of source at 40 CFR 63.101 and 40 CFR 63.191 
point to 40 CFR 63.100 and 40 CFR 63.190, respectively, where 
applicability is stated. For the HON, only those sources manufacturing 
as a primary product one or more of the chemicals in Table 1 to NESHAP 
subpart F, or tetrahydrobenzaldehyde, or crotonaldehyde; or using as a 
reactant or manufacturing as a product, or co-product, one or more of 
the HAP listed in Table 2 to NESHAP subpart F are subject to the 
provisions. For NESHAP subpart I, only those emissions specified from 
the processes subject to 40 CFR 63.190(b)(1) through (6) are subject to 
the fenceline provisions. Therefore, any concerns about obligations to 
meet fenceline monitoring requirements for pollutants developed as 
impurities or found in feedstock in trace amounts are unfounded, as 
these materials are not ``products,'' which, by definition, exclude by-
products, isolated intermediates, impurities, wastes, and trace 
contaminants per the definition at 40 CFR 63.101 or, in the case of 
NESHAP subpart I, are not the specified pollutants from the processes 
to which the subpart applies. For P&R I sources subject to NESHAP 
subpart U, we note that the fenceline monitoring requirements reference 
40 CFR 63.101 and the same logic can be applied.
    To the commenter's assertion about emissions from boilers, 
housekeeping, building maintenance, or lab and research activities 
triggering fenceline monitoring requirements, we note that these are 
not considered within SOCMI or P&R I sources per the applicability of 
the term at 40 CFR 63.100. Thus, there would be no need to implement 
fenceline monitoring if these are the only sources emitting benzene, 
1,3 butadiene, ethylene dichloride, vinyl chloride, EtO, or chloroprene 
at a facility. Therefore, for the reasons previously stated, there is 
no need to set a minimum threshold for fenceline monitoring as the rule 
already provides criteria targeting only SOCMI or P&R I sources using, 
producing, storing, or emitting one or more of the six considered 
pollutants and will not be triggered by low-level emissions from non-
source category processes.
    However, we agree with the commenter that the proposed language 
could be interpreted such that emissions from non-HON or P&R I 
processes could trigger the fenceline monitoring requirement. As such, 
we are revising 40 CFR 63.184(a)(1)(i) through (iv) and 40 CFR 
63.184(b)(1)(i) and (ii) to state that owners and operators with an 
affected source that uses, produces, stores, or emits one or more of 
the target analytes must conduct fenceline monitoring for the 
analyte(s) at their site. At proposal, we inadvertently used the word 
site in these sections instead of affected source, which may have led 
to confusion that non-HON or P&R I processes could have triggered 
fenceline monitoring obligations when there were no HON or P&R I 
processes at the site that use, produce, store, or emit benzene, 1,3 
butadiene, ethylene dichloride, vinyl chloride, EtO, or chloroprene. We 
believe this change clarifies our original intent and helps to more 
clearly target those facilities that were identified as needing 
fenceline monitoring as part of our original analysis (see Docket Item 
No. EPA-HQ-OAR-2022-0730-0091).
    To address concerns with facilities producing, using, storing, or 
emitting only low levels of benzene, 1,3-butadiene, ethylene 
dichloride, or vinyl chloride, we are finalizing burden reduction 
measures at 40 CFR 63.184(a)(3)(iii) and (b)(2)(iii). These provisions, 
similar to those provided at 40 CFR 63.658(e)(3) of NESHAP subpart CC 
for benzene, will allow facilities to skip fenceline measurement 
periods for specific monitors once a certain number of fenceline 
measurements are recorded to be one tenth or less than the finalized 
action levels. We believe the addition of these provisions will unify 
the finalized fenceline monitoring provisions between NESHAP subpart H 
and NESHAP subpart CC so that collocated refinery processes will not 
become subject to additional monitoring if they have already 
demonstrated levels of benzene at the fenceline that allow the owner or 
operator to qualify for a reduced sampling frequency and support 
facilities producing, using, storing, or emitting only low levels of 
the targeted pollutants from their affected sources. We note that these 
provisions are not being provided for EtO and chloroprene due to their 
associated risk and the finalized secondary actions levels having been 
set at three times the representative detection limit (RDL), and thus 
demonstrating sufficiently low fenceline concentrations to allow 
skipping monitoring periods is not possible. Additionally, for both EtO 
and chloroprene, even for the primary action levels, one-tenth of the 
action level would be below the method detection limit (MDL), and as 
such, skipping monitoring periods would not be possible for these 
pollutants. We also

[[Page 43007]]

note that for vinyl chloride, this option is limited to small sites 
with perimeters less than or equal to 5,000 meters. We have chosen to 
limit the reduced sampling frequency to these smaller sites because 
these are the only sites where the canister samples are taken at the 
same sampling location each sampling period; owners and operators of 
sites with a perimeter larger than 5,000 meters are required to rotate 
the sampling locations between sampling periods. As such, this 
complicates the determination as to whether a larger site has 
consistently low fenceline readings at a particular monitoring 
location.
    Comment: A commenter pointed out that when fenceline monitoring was 
established for refineries, the EPA stated that benzene was 
specifically chosen as the target analyte for petroleum refineries with 
the understanding that a single HAP served as a surrogate for all 
fugitive HAP, further stating that a single HAP simplified the 
determination of compliance and set a clear action level. The commenter 
contested that it is unclear why benzene cannot be the surrogate for 
the species listed under the proposed EPA Method 325 fenceline 
monitoring requirements. Moreover, the commenter added that a site 
should only have to do the chlorinated species or EtO monitoring if it 
is present in sufficient quantities such that their emissions would 
create a concentration higher than MDL at the perimeter; the commenter 
asserted that the EPA set their action levels based on modeling of site 
emission inventories but did not incorporate any rationale for why 
sites with less emissions must do such expensive monitoring. The 
commenter suggested that sites should have the option to model or 
demonstrate that their emissions would not be expected to exceed the 
action levels without embarking on a costly monitoring program that 
will just be reporting below detection level values.
    Response: Benzene was selected as a surrogate for all HAP as part 
of the fenceline monitoring provisions of NESHAP subpart CC due to its 
near universal presence in process streams. HON and P&R I processes are 
more diverse and there is no single chemical that is found with the 
same frequency in process streams as benzene in petroleum refineries. 
Setting one surrogate chemical to represent the variety of HON and P&R 
I processes considered as part of this rulemaking would not produce 
effective standards limiting fugitive emissions.
    To the commenter's request to be able to model concentrations at 
the fenceline to show that action levels will not be met, we point to 
table 2 through table 7 in the document titled Clean Air Act Section 
112(d)(6) Technology Review for Fenceline Monitoring located in the 
SOCMI Source Category that are Associated with Processes Subject to HON 
and for Fenceline Monitoring that are Associated with Processes Subject 
to Group I Polymers and Resins NESHAP (see Docket Item No. EPA-HQ-OAR-
2022-0730-0091). Fugitive emissions are, by nature, difficult to 
measure and record and the data collected via the CAA section 114 
request indicates that modeling is insufficient to anticipate fenceline 
concentrations of the six target pollutants considered. Therefore, we 
maintain that it is reasonable to require monitoring if a facility 
whose SOCMI or P&R I affected sources use, produce, store, or emit any 
of the pollutants specified at 40 CFR 63.184 to verify that actual 
concentrations at fenceline are below the finalized action levels. No 
changes are being made as a result of this comment.
    Comment: Commenters said that they have concerns regarding 
equipment and lab analytical capabilities on whether any laboratory is 
capable of performing proposed EPA Method 327. The commenters asserted 
that they were only able to identify one lab in North America that 
could meet all requirements of proposed EPA Method 327. A commenter 
suggested that to the extent that fenceline monitoring for EtO is 
required, the EPA should allow for the use of EPA Method TO 15 for 
initial monitoring for at least one (1) year until lab capabilities are 
further established; or alternatively, the initiation of fenceline 
monitoring be moved to at least two (2) years after the effective date 
of the final rule. Another commenter encouraged the EPA to actively 
engage in dialogue with commercial air laboratories in the method 
review process to ensure that the procedures meet the EPA's quality 
objectives of the program and also can be supported on a production 
scale, both of which will be critical for the successful implementation 
of the canister fenceline monitoring network. Another commenter 
requested that the EPA provide a list of laboratories able to perform 
proposed EPA Method 327.
    A commenter recommended that the EPA work with the New York State 
Department of Environmental Conservation (NYSDEC) to improve proposed 
EPA Method 327 given that NYSDEC analyzes VOCs in-house and has devoted 
considerable resources into refining its EtO measurement procedures 
over a seven year period. The commenter claimed that in a recent EPA 
performance audit of the NYSDEC laboratory required for NATTS sites, 
NYSDEC's EtO results were well within the 20 percent acceptability 
range and outperformed the referee laboratory. The commenter said 
proposed EPA Method 327 does not adequately address the issues that 
lead to inaccurate EtO measurements including, but are not limited to, 
the following:
     The preconcentration system must be optimized for the 
elimination of excess CO2 and water.
     Slip-lining the transfer line in the gas chromatography 
(GC) oven with the analytical column to minimize contact between the 
concentrated slug and transfer line ensures that all or most of the 
transfer takes place directly onto the analytical column, which 
maximizes performance.
     Ion 44 should be used for quantitation. Use of ions 15 or 
29 did not produce acceptable results in the NYSDEC laboratory. Ion 15 
was too noisy and ion 29 suffered from interference due to background 
contributions from nitrogen. For NYSDEC, interference from trans 2-
butene for ion 44 was not found to be an issue for normal ambient air 
samples due to the relatively low concentration of that substance in 
those samples. However, trans-2-butene can interfere with quantitation 
using ions 15 or 19, because, unlike ion 44, those are prominent masses 
in the mass spectrum of trans-2-butene.
     NYSDEC does not agree that bromofluorobenzene should be 
mandated as a tuning agent. NYSDEC has had success tuning prior to each 
run using perfluorotributylamine, per the manufacturer's 
recommendation, and has found that tuning to meet the 
bromofluorobenzene criteria can actually lower the sensitivity of the 
instrument.
     The use of internal standards for quantitation should not 
be mandated, especially for reactive chemicals like EtO and acrolein, 
as that procedure can produce biased results when the internal standard 
is not as sensitive to instrumental conditions as the target chemical. 
A better approach would be to use isotope dilution for the quantitation 
of these compounds, as the doped compounds would presumably react the 
same way in the analytical system. Given the anticipated very costly 
procurement of such internal standards, this should not be mandated, 
but instead suggested as a means to improve analytical performance for 
these reactive compounds. NYSDEC calibrates before, during, and after 
each analysis using the external standard approach and has complete 
confidence that the instrument is producing the best data within the 
confines of the system.

[[Page 43008]]

    The commenter added that they strongly believe that any method 
refinements that enable more accurate EtO measurements should be 
implemented in all ambient sampling for that pollutant, including 
samples collected at NATTS sites, because this would allow for 
comparison of fenceline and background sites without methodological 
considerations.
    Response: The EPA recognizes the commenters' concerns that 
laboratories may not currently have the capacity to conduct EPA Method 
327 according to the timeline we proposed. Therefore, we are revising 
the final rulemaking at 40 CFR 63.100(k)(12) (for HON) and 40 CFR 
63.481(p) (for the P&R I NESHAP) such that with the exception of 
fenceline monitoring of chloroprene at P&R I affected sources producing 
neoprene, owners and operators are not required to initiate fenceline 
monitoring until 2 years after the effective date of the final 
rulemaking. This expanded timeline is necessary to allow commercial 
labs to conduct the needed method development, to expand capacity, and 
to develop the logistics needed to meet the requirements in the final 
rule. For P&R I affected sources producing neoprene, we have changed 
the compliance date for fenceline monitoring of chloroprene to begin no 
later than October 15, 2024, or upon startup, whichever is later 
subject to the owner or operator seeking the EPA's authorization of an 
extension of up to 2 years from July 15, 2024. We note that that all 
affected sources producing neoprene (there is only one) already have a 
fenceline monitoring network in place for chloroprene as well as a lab 
contracted to provide analysis.
    We developed EPA Method 327 based on the requirements in EPA Method 
TO-15A, best practices for measuring compounds like EtO, and enhanced 
QA/QC required for a method that is to be used for compliance purposes. 
Regarding the specific recommendations made by the commenter, the EPA 
has made EPA Method 327 as performance-based as possible and considers 
it important, when possible, to avoid prescriptive requirements to 
allow commercial laboratories to develop their own approaches for 
analysis.
    Comment: Some commenters said that the EPA's proposed 300 parts per 
trillion (ppt) detection limit for EtO (and 900 ppt fenceline action 
threshold) are inadequate given that carcinogenic effects can be 
persistent and cumulative. These commenters claimed that EtO is toxic 
at 11 ppt in the ambient air; therefore, the EPA should mandate the use 
of advanced monitoring technologies to achieve lower detection limits 
and lower the action levels at the fenceline. A commenter remarked that 
in Louisiana, the typical residential location is not set at some safe 
distance from emissions; therefore, it is proper for the EPA to set 
minimum detection levels at the fenceline of the facility's property 
line, and not set the minimum detection level scalable to the duration 
of dispersion from the facility to the residential receptor location. 
Another commenter argued that developments in monitoring technology 
that lower the detection levels for listed HAP must be considered 
technological developments under CAA section 112(d)(6). This commenter 
contended that new technological developments, such as the use of 
proton transfer reaction-mass spectrometers and the use of Picarro 
products that use cavity ring-down spectrometers should be adopted by 
the EPA in its efforts to lower emissions in these source categories 
with the proposed fenceline monitoring efforts in the rules.
    Another commenter declared that it is important to note that the 
method detection limit is nearly the same as the concentration that is 
representative of 100-in-1 million risk; therefore, any detection 
corresponds to an unacceptable level of risk. On the contrary, a 
commenter said that given ambient air measurements made using the EPA's 
TO-15/TO-15A summa canister method have a detection limit for EtO 
higher than 0.02 ug/m3, it is possible that the actual level 
could be above the EPA's 100-in-1 million risk level even if a 
regulated source or an agency were to obtain non-detect results. This 
commenter said that they are very concerned that the EPA has 
established ambient air targets that neither an industrial source nor a 
regulatory agency can demonstrate that they are meeting with current 
air sampling methods; this raises practical questions about how one 
demonstrates compliance with these air quality targets.
    Response: The EPA recognizes the feedback from the commenters. We 
evaluated multiple measurement approaches that could be used for 
fenceline measurement, and there currently is not a measurement 
approach with reliable sensitivity at the level representative of 100-
in-1 million cancer risk. The EPA found the only technically feasible 
approach to measure EtO at the fenceline is a canister measurement 
approach and analysis via gas chromatography/mass spectrometry (GC/MS). 
We developed EPA Method 327 based on the requirements in TO-15A, the 
EPA's existing canister method, Best Practices for measuring compounds 
like EtO, and enhanced QA/QC required for a method to be used for 
numerical compliance purposes.
    We acknowledge the comment regarding real-time monitoring, and 
efforts are ongoing to evaluate different real-time monitoring 
approaches for EtO which could be applied to fenceline monitoring; 
however, we did not find these approaches to currently be technically 
or economically feasible. The EPA disagrees with the commenters that 
these real-time monitoring approaches are currently sensitive enough to 
currently be applied to fenceline monitoring; however, the EPA has a 
pathway for the use of these potential approaches through the 
alternative test method provisions in 40 CFR 63.7(f) when the required 
sensitivity is met, which is outlined in 40 CFR 63.184(i). We note that 
based on response to another comment, we are revising the entry for 40 
CFR 63.7(f) in the General Provisions table to NESHAP subpart F (Table 
3) such that 40 CFR 63.7(f) applies.
    Comment: Many commenters expressed concerns that the proposed 
provisions for an alternative test method at 40 CFR 63.184(i)(3) 
require the method detection limit of the alternative method to be at 
least an order of magnitude (i.e., ten-fold) below the action level for 
the compound(s) that will be monitored. A commenter indicated the 
proposed action level of 0.2 ug/m3 for EtO will prohibit 
some otherwise potentially viable alternative monitoring methods, 
including the Picarro air monitoring system and many open-path 
technologies. Commenters recommended that the EPA remove 40 CFR 
63.184(i)(3) in its entirety. Commenters indicated that this 
requirement limits flexibility and the ability for evaluation of 
alternate methods via the EPA's current alternate methods processes.
    A commenter further indicated that the proposed action levels for 
EtO and chloroprene are three times the RDL for each compound and, 
according to the EPA's technical memorandum, three times the RDL 
represents the level where a test method performs with acceptable 
precision. However, the commenter recommended that the EPA increase the 
multiplier to 5 for EtO for consistency with proposed EPA Method 327. 
The commenter argued that the requirement at 40 CFR 63.184(i)(3) for a 
ten-fold reduction in MDL for alternative test methods is so 
restrictive as to potentially eliminate the flexibility of real-time 
monitoring because the MDL was only five times lower than an already 
very low action level. The

[[Page 43009]]

commenter suggested the EPA revise the language at 40 CFR 63.184(i)(3) 
to require methodologies with detection limits at or below those of the 
reference standard (i.e., EPA Method 325A/B, EPA Method 327).
    Response: The EPA agrees with the commenters that the proposed 
requirement that the MDL of the alternative method be at least an order 
of magnitude less than the action level is too restrictive, and, 
therefore, in the final rule we have revised the requirement at 40 CFR 
63.184(i)(3) that the method detection limit of an alternative test 
method must be at least one-third of the action level for the 
compound(s) that will be monitored with the alternative method. The EPA 
considers three times the MDL to describe the limit of quantification 
of a method, or the point at which we have confidence in the accuracy 
and precision of a method. We note this requirement is also consistent 
with the EPA's approach for setting emission limits that are at least 
three times the RDL. Such an approach ensures that the standard is at a 
level that addresses measurement variability and is in a range that can 
be measured with reasonable precision. Requiring the detection limit of 
alternative measurement approaches to be at least one-third of the 
action level will ensure that measurements made near the action level 
are of reasonable precision.
    We note that while the EPA has reduced the requirements for the 
minimum detection limit of alternative measurement approaches, when 
calculating the sampling period [Delta]c, an owner or operator must 
still use zero as the lowest sample result when a measurement is below 
the MDL and must still use the MDL as the highest sample result if all 
sample results are below the MDL. The use of this approach in 
determining [Delta]c incentivizes the use of technology capable of 
measuring the lowest possible concentration for the target compound.
b. NSPS
    The EPA received comments in support of and against the proposed 
NSPS review, including our determination to include more stringent 
requirements for SOCMI equipment leaks, air oxidation unit processes, 
distillation operations, and reactor processes in the new NSPS subparts 
(i.e., NSPS subparts VVb, IIIa, NNNa, and RRRa, respectively).
    This section provides summaries of and responses to the key 
comments received regarding the NSPS review for SOCMI equipment leaks, 
air oxidation unit processes, distillation operations, and reactor 
processes. Comment summaries and the EPA's responses to additional 
issues raised regarding the proposed requirements resulting from our 
NSPS review are in the document titled Summary of Public Comments and 
Responses for New Source Performance Standards for the Synthetic 
Organic Chemical Manufacturing Industry and National Emission Standards 
for Hazardous Air Pollutants for the Synthetic Organic Chemical 
Manufacturing Industry and Group I & II Polymers and Resins Industry, 
which is available in the docket for this rulemaking.
i. Process Vents
    Comment: Several commenters said that they opposed the EPA's 
proposal to eliminate the TRE index value concept in the new NSPS 
subparts IIIa, NNNa, and RRRa. The commenters provided the following 
arguments:
     The TRE index value has been an integral part of many 
technology-based air standards since its initial development, serving 
as a mechanism for determining cost effectiveness and triggering the 
requirements for process vent control (see, e.g., the preamble to the 
1994 HON adoption, which states that the TRE concept is appropriate 
because it ``can be used to reflect all possible combinations of 
various factors that affect emission rates and likelihood of current 
control'' (citing 59 FR 19416) and ``would provide consistency between 
the HON[,] the recently issued [control techniques guidelines] for 
SOCMI process vents. . .[and] the applicability criteria for the three 
SOCMI process vents NSPS'' (59 FR 19418)). The EPA determined that BSER 
was 98 percent control (or an outlet concentration of 20 ppmvd at 3 
percent O2) of sources with a TRE less than or equal to 1.0 
when it promulgated these rules.
     While the EPA discusses its basis for removing the TRE 
index value > 1.0 alternative emission standard, it provides no 
discussion for why the limited applicability exemption in the NSPS (TRE 
> 4.0 for NSPS subpart III and TRE > 8.0 for NSPS subparts NNN and RRR) 
is proposed to be removed. The EPA must explain why this exemption 
should be removed and provide an opportunity for the public to comment 
before taking final action to modify or remove it.
     Voluntary control of some process vents with a TRE index 
value greater than 1.0 does not imply that controlling all process 
vents with a TRE index value greater than 1.0 constitutes the BSER. 
While controlling a subset of process vents with a TRE index value 
greater than 1.0 may be cost effective, the EPA's cost analysis for 
controlling such vents significantly understates the cost of installing 
additional controls such as a thermal oxidizer.
     The fact that a control device at one stationary source 
controls multiple process vents (as opposed to a single process vent) 
does not mean that in all cases control of multiple process vents is 
cost-effective. If the cumulative emissions from the process vents are 
small, then even controlling all of them with one control device is not 
cost effective.
     The EPA's conclusion that the TRE index value calculation 
is theoretical, complex, uncertain, and difficult to enforce is overly 
broad and cannot be applied to the regulated industry as a whole. The 
issues the EPA cites related to calculation of the TRE index value do 
apply in instances with few organic compounds in the stream, and in 
instances where facilities have readily available process data obtained 
from source testing, other direct measurements, or permit limits. 
Observations from one facility's TRE index value calculation approach 
should not be construed as representative of 284 facilities.
     The EPA's cost analysis (see Docket Item No. EPA-HQ-OAR-
2022-0730-0011) is not well supported and significantly underestimates 
the cost of installing and operating a thermal oxidizer. The EPA 
presents a total annual cost of $98,429 and a VOC emissions reduction 
of 9.1 tpy from the elimination of the TRE concept and the imposition 
of control requirements for all process vents. The EPA references the 
HON technology review memorandum in support of the cost calculations; 
however, that memorandum does not include a cost analysis of emission 
reduction calculations for NSPS sources. Furthermore, the EPA's 
proposed capital cost of $65,577 for a thermal oxidizer sized to 
control a 10 scfm stream is unrealistic; and it is also unrealistic to 
assume that a facility would install a thermal oxidizer simply for a 10 
scfm stream. The EPA's cost algorithm significantly underestimates the 
costs associated with design and engineering of such projects. A 
commenter provided an example at one of their existing affected 
facilities where if NSPS NNNa is triggered via modification or 
reconstruction, the facility would need to install control equipment 
estimated at a conservative amount of $500,000 in order to control 0.07 
tpy of VOC result from vents from recovery scrubbers, or about $7.14M 
per ton of VOC removed. The commenter

[[Page 43010]]

suggested that if the EPA is going to eliminate the TRE concept, that 
the EPA consider a cost effectiveness cut-off that is scaled to 
inflation that could avoid absurd results such as this.
     The EPA has ignored the fact that facilities that would 
now be required to control Group 2 halogenated streams would not only 
have to control organic HAPs using a thermal oxidizer, but would also 
have to incur costs to design, engineer, and install controls for acid 
gas and dioxin/furan emissions.
    A commenter questioned why removing the TRE concept for the SOCMI 
sector is not arbitrary given that no action was taken on the TRE 
concept in the recent RTR of the MON, conducted just 3 years ago.
    Some commenters suggested that the EPA could keep the TRE index 
value concept but raise the threshold, or establish a mass-based 
criterion below which emission controls are not required such that the 
rules would only require control where it is cost-effective (e.g., 
limit applicability of the NSPS to affected facilities at a site whose 
cumulative VOC emissions are greater than 25 tpy). A commenter pointed 
out that the proposed HON rulemaking requires control of process vents 
that emit greater than 1.0 lb/hr of total organic HAP, and suggested 
that a similar mass-based VOC emissions threshold below which control 
is not required be added to the SOCMI NSPS rules to avoid control being 
required for vent streams with very negligible VOC emissions. The 
commenter pointed out that the EPA included a mass-based emission 
threshold in NSPS subpart DDD at 40 CFR 60.560(g). The commenter 
provided an example of one of their distillation columns where the 
vacuum jet system vent emits very low amounts of VOC emissions (<0.0001 
lb/hr uncontrolled), the net heating value is very low or negligible, 
and the vent stream contains primarily nitrogen and/or water vapor. The 
commenter said that they would have to then build an emission control 
device to manage this stream.
    Response: As stated in the preamble to the proposed rule (88 FR 
25080, April 25, 2023), the statutory review of these process vent NSPS 
(subparts III, NNN, and RRR) focused on whether there are any emission 
reduction techniques used in practice that achieve greater emission 
reductions than those currently required by the current NSPS and 
whether any such practices have become the BSER. Based on this review, 
we have determined that the BSER for reducing VOC emissions from these 
SOCMI processes remains combustion (e.g., incineration, flares), and 
that the current emission standard of 98 percent reduction of TOC 
(minus methane and ethane) or reduction of TOC (minus methane and 
ethane) to an outlet concentration of 20 ppmv on a dry basis corrected 
to 3 percent oxygen continues to reflect the BSER.
    While we found no change in the BSER for reducing VOC emissions 
from air oxidation units, distillation operations, and reactor 
processes, we are finalizing the removal of the entire TRE concept, 
including the alternative of maintaining a TRE index value greater than 
1 without the use of control device and the limited applicability 
exemptions (i.e., TRE > 4.0 for NSPS subpart III and TRE > 8.0 for NSPS 
subparts NNN and RRR) for purposes of NSPS subparts IIIa, NNNa, and 
RRRa. We stand by the rationale we provided in the preamble to the 
proposed rule for not including the TRE concept in NSPS subparts IIIa, 
NNNa, and RRRa, which is summarized as follows: (1) Based on the 
responses to our CAA section 114 request, we observed that some 
facilities are controlling continuous process vents that are not 
required by the NSPS subparts III, NNN, or RRR to be controlled per the 
results of the TRE index value calculation; (2) based on the responses 
to our CAA section 114 request, we observed that facilities are routing 
multiple continuous process vents to a single APCD; (3) determining a 
TRE index value for certain process vent streams is often theoretical, 
can be extremely complicated, and is uncertain; and (4) because the TRE 
index value is largely a theoretical characterization tool, it can be 
very difficult to enforce.
    As stated in the preamble to the proposed rule (88 FR 25080, April 
25, 2023), in reviewing an NSPS to determine whether it is 
``appropriate'' to revise the standards of performance that reflects 
the degree of emission limitation achievable through application of 
BSER, the EPA considers the following information:
     Costs (including capital and annual costs) associated with 
implementation of the available pollution control measures.
     The amount of emission reductions achievable through 
application of such pollution control measures.
     Any non-air quality health and environmental impact and 
energy requirements associated with those control measures.
     Expected growth for the source category, including how 
many new facilities, reconstructions, and modifications may trigger 
NSPS in the future.
     Pollution control measures, including advances in control 
technologies, process operations, design or efficiency improvements, or 
other systems of emission reduction, that are ``adequately 
demonstrated'' in the regulated industry.
     Available information from the implementation and 
enforcement of current requirements indicating that emission 
limitations and percent reductions beyond those required by the current 
standards are achieved in practice.
    As previously stated, some owners and operators do not use the TRE 
index value to determine whether a vent stream is required to be 
controlled. While we agree with commenters that owners and operators 
control vent streams that have a TRE index value greater than 1.0 for 
reasons other than the desire to avoid the TRE calculation, the fact is 
that owners and operators are controlling vent streams that have a TRE 
index value greater than 1.0 (possibly to comply with state or local 
regulations regarding VOCs or to meet a BACT limit), which is 
information relevant to our CAA section 111(b)(1)(B) review of the 
standards. Given that the TRE concept has been used since each original 
NSPS adoption, we consider owners and operators controlling vent 
streams that have a TRE index value greater than 1.0 to be a pollution 
control measure (i.e., an advance in process operations) in our 
analysis. Additionally, the removal of the TRE concept simplifies the 
determination as to whether owners and operators must control a vent 
stream and thus, the applicability process is easier to implement.
    We disagree with commenters' assertions that the EPA did not 
provide evidence that the TRE concept is largely theoretical and, as a 
result, difficult to verify. As identified in the document titled Clean 
Air Act Section 112(d)(6) Technology Review for Continuous Process 
Vents Located in the SOCMI Source Category that are Associated with 
Processes Subject to HON, Continuous Front-end and Batch Front-end 
Process Vents Associated with Processes Subject to Group I Polymers and 
Resins NESHAP, and Process Vents Associated with Processes Subject to 
Group II Polymers and Resins NESHAP (Docket Item ID No. EPA-HQ-OAR-
2022-0730-0094), one facility that received the CAA section 114 request 
provided over 300 pages of modeled runs used to determine certain 
characteristics of their continuous process vents to be utilized as 
part of the TRE index value calculations. Reviewing this information 
revealed

[[Page 43011]]

that in many cases, the facility struggled to unify the modeled runs 
with actual conditions at the facility and in some cases made arbitrary 
decisions to allow the model to function. While we agree with 
commenters that the TRE index value can be derived from less 
theoretical methods, other responses to the CAA section 114 request did 
not indicate how parameters used in the TRE index value calculations 
were determined and commenters did not provide sufficient information 
to show which methods were most common throughout industry. Given the 
theoretical nature of the TRE index value, the EPA maintains that 
verifying TRE index values is arduous because it can involve relying on 
significant process knowledge in order to confirm compositions of vent 
streams, vent stream flowrates, vent stream net heating values, and 
hourly emissions. It may also require verification of other facility 
assumptions (e.g., operational conditions and constraints), especially 
if modeling was used. This logic applies equally to existing, new, and 
modified sources and thus is one of the reasons why the EPA is not 
including the TRE concept in NSPS subparts IIIa, NNNa, and RRRa as part 
of this rulemaking.
    We agree with commenters that the TRE index value has been an 
integral part of many technology-based air standards since its initial 
development. In fact, we said as much in the document titled CAA 
111(b)(1)(B) review for the SOCMI air oxidation unit processes, 
distillation operations, and reactor processes NSPS subparts III, NNN, 
and RRR (see Docket Item No. EPA-HQ-OAR-2022-0730-0011). The TRE 
concept is almost 40 years old; it was first introduced in a December 
1984 EPA document (EPA-450/3-84-015; see attachment to Docket Item No. 
EPA-HQ-OAR-2022-0730-0011). However, even if it has been used in the 
past, we believe that for purposes of the new NSPS subparts NNNa, IIIa, 
and RRRa, certain aspects of its underlying development are clearly no 
longer applicable or appropriate. For example, the EPA stated in the 
1984 supporting materials (EPA-450/3-84-015) that the Agency attempted 
to make the TRE index independent of inflation (e.g., the EPA assumed 
fixed relative costs of various resources, such as carbon steel and 
electricity), yet it is impossible to ignore inflation in the TRE 
calculations due to the time that has passed since it was developed 
(e.g., costs of carbon steel and electricity have undoubtedly increased 
since the development of the TRE index).
    Although the TRE index value may allow owners and operators to 
allocate resources efficiently and ensure that the most significant 
emission sources are targeted for control, the current use of the TRE 
index value is only based on controlling a single vent stream with a 
single APCD. This is an unrealistic scenario when compared to how 
affected facilities actually control their vent streams; it is much 
more likely that a facility routes numerous vent streams to the same 
APCD (which is evident from observing the responses to our CAA section 
114 request).
    We do agree with commenters that our cost estimate for installing a 
new recuperative thermal oxidizer (to control vent streams subject to 
the NSPS) included in the proposed rule is unrealistic (e.g., we 
severely underestimated flow rates needed to route vent streams with 
low flow to APCDs). Although we still believe the use of the EPA's 
control cost template is appropriate to estimate the cost of installing 
a new recuperative thermal oxidizer (to control vent streams subject to 
the NSPS), we revised our estimates to reflect the limitations of the 
correlations associated with the EPA's control cost template, which 
starts with a flow rate of 500 scfm. With these corrections, we 
estimate that the average TCI to install a new recuperative thermal 
oxidizer is about $167,000 (as opposed to the $66,000 estimate provided 
in the proposed rule). However, our estimate is still much less than 
the $500,000 estimate provided by commenters. One explanation for this 
is that commenters may have used a much higher flow rate (e.g., 5,000 
scfm as opposed to 500 scfm) and a ``Regenerative Thermal Oxidizer'' in 
their cost analysis instead of a ``Recuperative Thermal Oxidizer.'' 
Moreover, commenters did not provide supporting information for their 
estimated capital costs, so the EPA cannot corroborate their assertions 
regarding cost.
    In light of the fact that commenters were generally concerned about 
the cost estimate for installing a new recuperative thermal oxidizer 
(to control vent streams subject to the NSPS), we performed additional 
analyses to evaluate the cost effectiveness of not including the TRE 
concept in the new NSPS IIIa, NNNa, and RRRa. Instead of using $500,000 
as suggested by a commenter, we used a TCI of $1,000,000 and the EPA's 
control cost template (for installing a new recuperative thermal 
oxidizer with 70 percent energy recovery). Even with this change in our 
analysis, we continue to believe that revising the standard from a TRE 
calculation to control of all vent streams is still cost effective when 
considered along with the suite of process vent requirements evaluated 
as a whole under our NSPS review. As stated in the preamble to the 
proposed rule (88 FR 25080, April 25, 2023), we considered four 
different NSPS-triggering scenarios and a suite of proposed process 
vent requirements combined together (including not only revising the 
standard from a TRE calculation to control of all vent streams, but 
also new operating and monitoring requirements for flares, the addition 
of maintenance vent requirements, and the addition of adsorber 
monitoring requirements). In this context, we conclude that, even with 
our reevaluation of TCI for installing a new recuperative thermal 
oxidizer, the cost-effectiveness value of the suite of process vent 
requirements evaluated under our NSPS review is $4,890 per ton VOC 
(instead of $4,570 per ton VOC as proposed), which we consider to be 
reasonable.\51\ For further details on how we estimated cost and VOC 
emissions reductions, see the document titled CAA 111(b)(1)(B) review 
for the SOCMI air oxidation unit processes, distillation operations, 
and reactor processes NSPS subparts III, NNN, and RRR--FINAL, which is 
available in the docket for this rulemaking.
---------------------------------------------------------------------------

    \51\ This cost effectiveness value is within the range of what 
the EPA has considered reasonable for the control of VOC emissions 
in other recent NSPS rulemakings. See, e.g., 88 FR 29982 (May 9, 
2023) (finding a value of $6,800/ton of VOC emissions reductions 
cost-effective for automobile and light duty truck surface coating 
operations) (NSPS subpart MMa); see 89 FR 16820 (March 8, 2024) 
(finding value of $5,540 per ton of VOC reduction reasonable for 
controls identified as BSER in Oil and Natural Gas NSPS subpart 
OOOOb and Emission Guidelines subpart OOOOc).
---------------------------------------------------------------------------

    We disagree with the commenters' suggestion to include the TRE 
concept in the new NSPS subparts NNNa, IIIa, and RRRa but raise the TRE 
index value threshold to something greater than 1.0 (as opposed to not 
including the TRE concept in its entirety, as proposed). Regarding a 
commenter's assertion that removing the TRE concept is arbitrary given 
no action was taken on the TRE concept in the MON RTR, we note that we 
did not have data related to Group 2 process vents while developing 
revisions to the MON. Setting an emission threshold with no knowledge 
of which Group 2 MON vent streams would be impacted and the potential 
cost or reductions associated with that revision would not have been 
appropriate.
    Finally, we agree with the commenter's request to include a mass-
based criterion below which emission controls are not required, but 
only for NSPS subparts IIIa and NNNa (not NSPS

[[Page 43012]]

subpart RRRa). We believe a mass-based exemption criterion is not 
needed for NSPS subpart RRRa given that we are finalizing, as proposed, 
a volumetric flowrate-based exemption (0.011 scm/min at 40 CFR 
60.700a(c)(3)) as well as a concentration-based exemption (300 ppmv TOC 
as measured by EPA Method 18 or 150 ppmv TOC as measured by EPA Method 
25A at 40 CFR 60.700a(c)(7)) in NSPS subpart RRRa. It is clear from 
supporting documents that the EPA included the concentration-based 
exemption in NSPS subpart RRR with the intent to relieve owners and 
operators of controlling vent streams with very low amounts of VOC 
emissions (see 58 FR 45948, August 31, 1993, as well as the document 
titled Selection of the Low Concentration Cutoff, which is available in 
the docket for this rulemaking). Even so, we recognize that NSPS 
subparts IIIa and NNNa do not contain these same exemptions. Therefore, 
we are finalizing a mass-based exemption criterion of 0.001 lb/hr TOC 
(for which emission controls are not required) for NSPS subparts IIIa 
and NNNa at 40 CFR 60.610a(c)(1) and 40 CFR 60.660a(c)(6), 
respectively. We based this criterion on the combination of both the 
volumetric flowrate- and concentration-based exemptions that are 
included in NSPS subparts RRR and the final RRRa. In other words, the 
0.001 lb/hr TOC mass-based exemption criterion which we are finalizing 
in NSPS subparts IIIa and NNNa is roughly equal to a vent stream with a 
volumetric flowrate of 0.011 scm/min and a TOC concentration of 300 
ppmv (assuming a TOC molecular weight of 80 grams per mole) included in 
NSPS subparts RRR and the final RRRa. We also note that new affected 
facilities should have greater flexibility in selecting cost-effective 
control options during the design and construction phase (e.g., owners 
and operators at greenfield sources are likely to have more flexibility 
in spatial considerations compared to those at an existing source 
leading to a potential reduction in the amount of complex piping and 
construction materials needed to install an APCD).
    Comment: A commenter said they support the EPA's proposal to 
eliminate the relief valve discharge exemption from the definition of 
``vent stream'' in NSPS, subparts IIIa, NNNa, and RRRa such that any 
relief valve discharge to the atmosphere of a vent stream is a 
violation of the emissions standard. However, several other commenters 
opposed this proposal. Commenters requested that the EPA revise the 
term ``violation'' to ``deviation'' in NSPS subparts IIIa (at 40 CFR 
60.612a(b)), NNNa (at 40 CFR 60.662a(b)), and RRRa (at 40 CFR 
60.702a(b)) regarding the prohibition of relief valve discharges (e.g., 
PRD releases to the atmosphere) and use of bypass lines. In addition, 
the commenters requested that the EPA add the same PRD work practice 
standard that the EPA has finalized in the MON (at 40 CFR 
63.2480(e)(3)- (8)) and Ethylene MACT (at 40 CFR 63.1107(h)(3)-(8)), 
and proposed in the HON (at 40 CFR 63.165(e)), into NSPS subparts IIIa, 
NNNa, and RRRa at 40 CFR 60.612a(d), 60.662a(d), and 60.702a(d), 
respectively. The commenters argued that the proposed regulatory 
approach regarding eliminating the relief valve discharge exemption 
does not represent BSER for the SOCMI source category given that relief 
valve discharges that are routed to the atmosphere are necessary at 
times for at least the following reasons:
     Hazardous oxidation products: A discharge to a flare would 
result in combustion products that are not desirable.
     Chemical reactivity within flare system: Some affected 
facilities may use a single large flare for emission control for a 
given process area or group of process areas.
     Physical obstruction within flare header system: In some 
cases, there is a potential for certain compounds to block or restrict 
portions of the flare header.
     Streams containing oxygen: Some process streams and 
equipment that PRDs protect contain mixtures of organic compounds and 
oxygen especially in air oxidation processes. Some air oxidation 
reactors have rupture discs as PRDs, and swings in air supply can cause 
a rupture disc to fail.
     Intolerable backpressure on the PRD: The operating 
pressure in a large flare header system could increase from just 
slightly over atmospheric pressure to a pressure in the 10-20 psig 
range or higher for certain periods of time when upset venting occurs 
or another highly intermittent flow occurs.
     Intolerable liquid load on the flare Knock Out (KO) drum: 
If the PRD is in liquid service, it is not acceptable to add a high-
volume liquid discharge from a PRD into a flare header. Flare KO drums 
have a finite liquid capacity. If the liquid is highly volatile, severe 
pipe contraction (due to auto-refrigeration) can potentially cause a 
loss-of-containment failure of the flare header piping.
     Technically impossible to collect discharges from PRDs on 
portable/mobile containers.
     It is not technically or economically feasible to install 
a new large flare system to capture the discharge from a small number 
of new PRDs from a new, reconstructed, or especially a modified SOCMI 
source regulated under NSPS subparts IIIa, NNNa, and RRRa.
     Any chemical manufacturing facility with the potential to 
release high volumes of chlorinated (halogenated) material from a PRD 
release would be required to install and operate an oversized thermal 
oxidizer equipped with acid gas controls that would be operated on 
stand-by anytime the facility is in operation; and this operating mode 
results in the facility also emitting large amounts of secondary 
emissions such as greenhouse gases, VOCs, NOX, and CO.
     PRDs prevent catastrophic breaches of process equipment 
that could endanger both the lives of plant employees and nearby 
communities, and result in damage to property; these catastrophic 
breaches would result in much greater emissions than those resulting 
from a PRD release. PRDs minimize the loss of process materials to the 
surrounding environment.
    Commenters also argued that it is not cost-effective to route all 
PRDs to control devices. Some commenters pointed out that given that 
the EPA concluded it is not cost-effective to route all PRDs to control 
for HON and P&R (and instead proposed a work practice standard for PRDs 
that vent to the atmosphere), it is unclear how the Agency could 
presume such a requirement would be cost-effective as BSER and 
appropriate to establish as an NSPS requirement. Additionally, the 
commenters asserted that the only analysis the EPA uses to justify the 
proposed change is the identification of a single lowest achievable 
emissions rate (LAER) condition in the reasonably available control 
technology (RACT)/BACT/LAER clearinghouse database. The commenters 
argued that by equating a single LAER determination (based on the EPA's 
RACT/BACT/LAER clearinghouse database search regarding ID TX-0813171 
for the ``Linear Alpha Olefins Plant,'' which is operated by INEOS 
Oligomers USA, LLC) to BSER and not performing any additional analysis, 
the EPA has ignored the statutory requirements of CAA Section 111(a)(1) 
in that the Agency did not adequately account for the cost of achieving 
reductions, nor did the Agency consider non-air quality health and 
environmental impacts and more specifically, energy requirements.
    A commenter added that PRDs serve a vitally important role as the 
last line of defense to protect vessels and

[[Page 43013]]

equipment from mechanical failure should an overpressure situation 
occur; therefore, it is important that they work correctly. The 
commenter asserted that in the unlikely event that a pressure relief 
event occurs, it is important to have the opportunity to analyze such 
situations and implement corrective actions to further minimize the 
chance that such an event will occur in the future.
    Response: We disagree with the commenters that the removal of the 
exemption for PRD releases to atmosphere is not BSER for NSPS subparts 
IIIa, NNNa, and RRRa and that the EPA has ignored its obligations to 
CAA section 111. For a thorough explanation of our BSER analysis and 
the ways in which the EPA complied with the statutory requirements of 
CAA section 111, refer to the document titled CAA 111(b)(1)(B) review 
for the SOCMI air oxidation unit processes, distillation operations, 
and reactor processes NSPS subparts III, NNN, and RRR (see Docket Item 
No. EPA-HQ-OAR-2022-0730-0011) and section III.C.3.b of the proposal 
preamble (88 FR 25080, April 25, 2023). No changes are being made to 
the final rule as a result of this comment.
    While commenters state that only one facility was identified as 
part of the RACT/BACT/LAER clearinghouse database, we note that one 
additional facility was also identified as having prohibitions on PRDs 
releasing to the atmosphere and were thus choosing to route those 
pieces of equipment to an APCD. The Lyondell Chemical Bayport Choate 
Plant in Harris, TX (permit number 137789) was identified as part of 
our RACT/BACT/LAER clearinghouse database search, but did not properly 
state that they were also under restrictions for PRD releases to 
atmosphere for streams containing more than 1 percent VOC. See the 
updated document titled CAA 111(b)(1)(B) review for the SOCMI air 
oxidation unit processes, distillation operations, and reactor 
processes NSPS subparts III, NNN, and RRR--FINAL, which is available in 
the docket for this rulemaking. Lyondell and the Linear Alpha Olefins 
Plant were placed under these restrictions by the state of Texas in 
2017 and 2015, respectively. In fact, the TCEQ published the document 
titled Air Permit Technical Guidance for Chemical Sources Fugitive 
Guidance in June 2018, which is available in the docket for this 
rulemaking. Section III of the document states that ``the following 
practices are generally considered to be the minimum for BACT . . . . 
New relief valves are required to vent to a control device for any 
potential releases and as a result, any fugitive emissions are reduced. 
Exceptions may be made if venting relief valve to control will result 
in a safety concern, but this does not exempt the company from controls 
such as equipping the valve with a rupture disk and pressure sensing-
device.'' The EPA maintains that between the guidance provided by the 
TCEQ and ability of the two identified facilities to meet the 
requirements, prohibiting PRD releases to atmosphere is adequately 
demonstrated for purposes of determining BSER.
    We also disagree with commenters' descriptions of why PRDs 
releasing to atmosphere are necessary. We note that owners and 
operators are not obligated to route PRDs to an APCD. In fact, we agree 
with commenters that PRDs act as a last line of defense in uncommon 
process conditions. Therefore, the EPA expects that a well-controlled 
and rigorously designed process will not experience PRD releases 
regularly, if at all. In those situations, as described by the 
commenter, where PRD releases are necessary to prevent further 
catastrophic failure, we agree with the commenter that safety is a 
priority and PRD releases may be necessary. However, we note that we 
are not prohibiting the release of PRDs in totality, just to 
atmosphere, or their use in general and that process conditions leading 
to catastrophic failure should be well outside regular operating 
conditions. Therefore, the EPA expects that PRDs used to prevent 
catastrophic failure can continue to function without reasonable 
concern for release to atmosphere during regular operating conditions. 
If the facility is concerned about a PRD releasing to atmosphere during 
a catastrophic failure event, which should be exceptionally rare to 
begin with, they may choose to route those emissions to an APCD to 
avoid incurring a violation. The EPA maintains that releasing 
uncontrolled volumes of emissions to atmosphere as a result of 
preventable process upsets is characteristic of a violation.
    To that point, we are not requiring owners or operators to route 
PRD releases to an APCD, and there are no cost, non-air quality health, 
environmental, or energy requirements as a result of this change. The 
EPA expects no additional equipment will be needed for facilities to 
meet the finalized provisions given our agreement with commenters that 
PRD releases are unlikely to occur at all assuming a process is 
rigorously designed, maintained, and controlled. If the owner or 
operator chooses to control PRD emissions, it is their responsibility 
to select whichever control method is most appropriate considering, 
among other factors, the composition of the release, location of the 
equipment, and overall safety. We note that facilities with new sources 
that choose to route PRD emissions to an APCD will have the flexibility 
in the design and construction phase to select options they consider to 
be cost-effective and plan based on key criteria like placement of the 
equipment. For existing sources that trigger the NSPS subpart IIIa, 
NNNa, or RRRa via a modification or reconstruction, it is the 
responsibility of the owner or operator to make the determination if 
retrofitting PRDs to release to an APCD is feasible, cost-effective, 
and necessary against the potential to incur violations as a result of 
atmospheric release or if alternative process controls or operational 
practices are more appropriate. Any cost, non-air quality health, 
environmental, or energy impacts associated with the owner or operator 
controlling PRD emissions, including those from halogenated streams as 
identified by the commenter, were not considered as part of the BSER 
analysis because they are only incurred at the discretion of an owner 
or operator if they choose to go beyond the requirements of this 
rulemaking and pursue control of emissions. For the above reasons, the 
EPA has met its obligations under CAA section 111(a)(1).
    We disagree with the commenter that the use of the term 
``violation'' should be replaced with ``deviation'' in NSPS subparts 
IIIa (at 40 CFR 60.612a(b)), NNNa (at 40 CFR 60.662a(b)), and RRRa (at 
40 CFR 60.702a(b)). We used the term ``violation'' in the SOCMI NSPS 
(subparts IIIa, NNNa, and RRRa) to be consistent with the HON standards 
that also regulate the SOCMI source category.
ii. Equipment Leaks
    Comment: A commenter contended the EPA's BSER analysis was 
insufficient because it failed to consider key equipment leak control 
technologies, such as OGI, leak detection sensor networks (LDSNs), and 
even options that the EPA previously considered in 2007 when developing 
NSPS subpart VVa. The commenter asserted that the EPA must consider 
these developments when evaluating and establishing the BSER for new, 
reconstructed, and modified SOCMI process units. The commenter stated 
that the EPA's review of the LDAR requirements in NSPS subpart VVa is 
inconsistent with other reviews of NSPS equipment leak standards. In 
particular, the commenter noted that in its November 15, 2021 proposal 
for the

[[Page 43014]]

Crude Oil and Natural Gas source category, the EPA evaluated several 
monitoring techniques, and combinations of techniques, to determine if 
the BSER for equipment leaks at natural gas processing plants should be 
revised, including bimonthly and quarterly OGI monitoring in 
combination with annual EPA Method 21 monitoring at a leak definition 
of 10,000 ppm, and bimonthly OGI monitoring on all equipment with the 
potential for VOC emissions. The commenter asserted that the EPA's 
failure to consider OGI is erroneous considering the EPA has 
established an Alternative Work Practice at 40 CFR 60.18(g) through (i) 
that allows sources subject to NSPS subparts VV and VVa to conduct 
bimonthly OGI monitoring with annual EPA Method 21 surveys at 500 ppm 
as an alternative to conducting EPA Method 21 monitoring at the leak 
definitions and frequencies in those subparts. The commenter added that 
at a minimum, the EPA should evaluate whether this alternative work 
practice now represents the BSER for NSPS subpart VVb.
    Response: For the reasons explained below, we find that none of the 
control options raised in the comment above (i.e., OGI, LDSN and 
options considered in the last review) is BSER for equipment leaks from 
new, modified, and reconstructed SOCMI process units.
    Regarding OGI, we do not believe it replaces EPA Method 21 as BSER 
for equipment leaks from SOCMI process units for the following reasons. 
First, as shown by our equipment leaks regulations for the SOCMI 
industry since the early 1980s, leaks in the area of 500 to 1000 ppm 
can be detected using EPA Method 21 and repaired for most equipment in 
this industry. The EPA acknowledges that OGI is effective at finding 
large leaks quickly for many compounds, but, while OGI is capable of 
detecting low-level leaks under certain conditions, it is difficult for 
a camera operator to find low level-leaks with OGI under the range of 
conditions that leak surveys are generally conducted, including 
variable ambient and equipment temperatures, complex backgrounds, and 
elevated wind speeds. Additionally, the compounds that can be detected 
by an OGI camera are limited to the compounds that have a peak in the 
spectral range of the filter on the OGI camera (generally around 3.2-
3.4 micron for cameras used to detect hydrocarbons). While many 
compounds of interest do have a peak in this range, the variety of 
chemicals found at SOCMI facilities is very broad, and not all of these 
chemicals can be observed with an OGI camera. For example, ethylene and 
acetaldehyde have very weak peaks in the spectral range common to OGI 
camera filters, making it extremely difficult to see these compounds 
with an OGI camera. For those compounds that can be observed with an 
OGI camera, the detection range of the camera varies, and some 
compounds must be emitted in high quantities before being observed. For 
example, it is expected that twice as much styrene must be emitted as 
xylene (any isomer) before the emissions are visible with an OGI 
camera.\52\ For these reasons, the use of OGI is not appropriate for 
the SOCMI source category.\53\
---------------------------------------------------------------------------

    \52\ See Technical Support Document, Optical Gas Imaging 
Protocol (40 CFR part 60, Appendix K), September 2023 for more 
information related to detection of compounds with OGI.
    \53\ In contrast, the majority of VOC emissions at onshore 
natural gas processing plants are expected to be comprised of 
compounds such as butane, pentane, hexane, benzene, toluene, 
xylenes, and ethylbenzene; the type of compounds emitted are 
expected to be fairly uniform from all onshore natural gas 
processing plants. In addition to VOC, leaks at onshore natural gas 
processing plants generally contain methane. All of these compounds 
can be identified with an OGI camera. For this reason, OGI is 
effective in detecting leaks from onshore natural gas processing 
plants, as the commenter observes, but may not be effective for 
certain SOCMI process units, where makeup of VOC emissions varies 
widely across the source category.
---------------------------------------------------------------------------

    Regarding LDSNs, which use an array of continuous sensors to find 
leaks, we agree that these systems can effectively be used to trigger 
and target EPA Method 21 or OGI monitoring and leak repair, but an 
effective system depends on the sensitivity of the sensors, the spacing 
of the sensors, and the trigger used to deploy a ground monitoring 
crew. It is difficult to develop vendor-agnostic monitoring 
requirements that can be incorporated generically within a rule, and we 
do not have the necessary information to do so at this time. While we 
are continuing to look at how to develop a standardized approach for 
sensor networks, we are not prepared to include provisions for a 
continuous sensor network for the SOCMI source category at this time. 
However, owners or operators can elect to submit a request for an 
alternative means of emission limitation for using a site-specific 
sensor network monitoring plan.
    Finally, the commenter claims that the EPA must evaluate options 
that we had previously considered while promulgating NSPS subpart VVa 
in 2007. The EPA does not have information, nor has the commenter 
provided any, indicating that there has been development since the last 
review to any such previously rejected option that warrants evaluation 
in the present review.
    Comment: A commenter stated that the EPA's focus on lowering the 
leak definition for valves from 500 ppm to 100 ppm is inconsistent with 
recent EPA focus on targeting large emissions sources, as was done for 
the oil and gas industry. The commenter stated that rulemaking targeted 
finding large leaks faster, while in the review for NSPS subpart VVa, 
the EPA focused on reducing a small population of small leaks by 
lowering the leak definition for valves from 500 ppm to 100 ppm. The 
commenter added that the EPA's analysis for NSPS subpart VVa 
demonstrates this proposed change only results in reducing 0.64 tpy of 
VOC emissions per affected facility beyond the baseline. The commenter 
also stated that the facility-level leak inspection data that the EPA 
has available shows that leaks between 100 ppm and 500 ppm are not very 
common. The commenter specified that the EPA has access to at least one 
data set containing leak inspection results for nearly 3,000 components 
at a chemical manufacturing facility. The commenter added that the 
average EPA Method 21 reading was over 25,000 ppm, with the minimum 
reading for valves was 747 ppm and minimum reading for connectors was 
1,000 ppm, underscoring the importance of entirely preventing 
significant leaks (as well as quickly identifying and remediating 
others). The commenter recommended, in addition to strengthening the 
standards as it has proposed, that the EPA evaluate the use of 
additional technology, such as low emission valves and valve packing 
and connectors less likely to leak, in order to prevent the presence of 
these large emissions. The commenter concluded that this evaluation 
would allow the EPA to take action on preventing emissions from 
occurring at these high rates and potentially result in the 
determination that a combined program of low-emissions technology with 
regular EPA Method 21 monitoring and leak repairs is the BSER for SOCMI 
equipment leaks.
    Response: The EPA disagrees that the actions taken in this NSPS 
rulemaking are inconsistent with the actions taken in other recent NSPS 
rulemakings, specifically the oil and gas NSPS (see 89 FR 16820 (March 
8, 2024)). The rulemaking for the oil and gas sector are focused on 
finding large leaks faster while the leak regulation for SOCMI does 
not, because there are key differences between the oil and gas and the 
SOCMI source category. The SOCMI industry has been complying with 
equipment leak regulations since the early 1980s, and leaks are 
expected to be

[[Page 43015]]

much lower in SOCMI than for the oil and gas industry. As a result, the 
leak definitions that SOCMI facilities must comply with are already 
very low, 500 to 1000 ppm for most equipment, and the proposed and 
final rule lowers leak definitions to 100 ppm for valves to gain even 
more emissions reductions.
    Additionally, the data set referenced by the commenter was 
collected over several years. The chemical facility associated with the 
data set conducted an OGI survey and then recorded the EPA Method 21 
reading for any leaks found by OGI. However, the data set does not 
include any information related to leaks that could have been found 
with EPA Method 21 but not OGI. Therefore, the EPA cannot conclude that 
there are few leaks between 100 ppm and 500 ppm at chemical plants 
based on this data set. What this data set does demonstrate is that 
there is no evidence that OGI can find low-level leaks at chemical 
plants.
    In the final rule (NSPS subpart VVb), we are not requiring specific 
types of equipment be used to meet the 100 ppm leak definition for 
valves. However, in order to meet the 100 ppm leak definition for 
valves, we anticipate that facilities will need to use low-emission 
valves or packings. The average cost-effectiveness (with recovery 
credits) of lowering the leak definition for valves in gas/vapor or 
light liquid service from 500 ppm to 100 ppm, is $2,780 per ton of VOC 
reduced, and the EPA estimates this provision could result in 
reductions of more than 20 tpy of VOC.
    Comment: A commenter contended that the EPA's proposed definition 
for capital expenditures in NSPS subpart VVb narrows the reach of 
modification and would result in the exclusion of certain process units 
from applicability to the subpart through modification. For NSPS 
subpart VVb, the commenter opposed the two proposed calculations for 
``X''. The commenter explained that by proposing a value for ``X'' to 
be ``2023 minus the year of construction'' for sources with a 
construction date after January 6, 1982 and before January 1, 2023, the 
EPA has categorically exempted any process unit from ever becoming 
subject to NSPS subpart VVb through modification if its date of 
construction is prior to January 6, 1982. The commenter contended that 
this error must be addressed in the final rule to not create a loophole 
exempting the oldest of these SOCMI process units from ever becoming 
subject to NSPS subpart VVb through modification. The commenter 
suggested revising the value for ``X'' to mean ``2023 minus the year of 
construction'' without the need to bookend this definition with 
specific dates. The commenter added that the EPA should first evaluate 
more recent developments on the definition of ``capital expenditure'' 
inclusion in the final NSPS subpart VVb. The commenter also opposed the 
proposed change of ``X'' for sources constructed in the year 2023 in 
order for X to not be equal to zero, which results in an equation that 
cannot be solved. The commenter noted that the EPA has addressed this 
same issue recently through specific changes to the definition of 
capital expenditure promulgated in the technical amendments to NSPS 
subpart OOOOa for equipment leaks at onshore natural gas processing 
plants. The commenter explained that in those amendments, the EPA 
revised the equation used to determine ``Y'' (the percent of 
replacement costs) to remove the variable ``X'' (and logarithmic 
function) and instead the EPA specifically defined ``Y'' as ``the 
Consumer Price Index (CPI) of the date of construction divided by the 
most recently available CPI of the date of the project, or ``CPIN/
CPIPD''. The commenter contended that at a minimum, the EPA must 
consider this calculation of ``Y'' when defining ``capital 
expenditure'' in NSPS subpart VVb and discuss why the use of the CPI-
based ratio is not appropriate for affected facilities before 
finalizing the proposed definition with the appropriate revisions to 
close loopholes.
    Response: We agree with the commenter that in the proposed 
definition of ``capital expenditure'' in NSPS subpart VVb, the value of 
``X'' should not be bounded by the NSPS subpart VV date of January 6, 
1982. We also agree with the commenter that we should update the 
definition of ``capital expenditure'' to use the CPI in the equation 
for ``Y'' in NSPS subpart VVb. For the reasons discussed below, the EPA 
is finalizing the capital expenditure definition in NSPS subpart VVb to 
state in part that the value of ``Y'' is calculated using the CPI of 
the date of original construction of the process unit divided by the 
most recently available CPI of the date of the project.
    In the early 1980s, some facilities were having trouble determining 
capital expenditure because records for costs were not available for 
determining the original basis of the affected facility.\54\ The EPA 
developed an alternative method to NSPS subpart A which enabled 
companies to use replacement cost rather than original cost. In the 
alternative method, an inflation index is applied to the replacement 
cost to approximate the original cost basis of the affected facility. 
The relationship between the replacement and original cost ultimately 
ended up in the formulas contained in the definitions of ``capital 
expenditure'' in NSPS subparts VV and VVa.\55\
---------------------------------------------------------------------------

    \54\ Pursuant to the NSPS subpart A definition of ``capital 
expenditure'' companies would need to know the original cost of the 
affected facility to determine capital expenditure.
    \55\ See Office of Air Quality Planning & Standards, U.S. 
Environmental Protection Agency. EPA-450/3-83-015B, Petroleum 
Fugitive Emissions--Background Information For Promulgated Standards 
at 4-3 to 4-7 (Oct. 1983), which is available in the docket for this 
rulemaking.
---------------------------------------------------------------------------

    The formulas for ``Y'' in the definitions of ``capital 
expenditure'' in NSPS subparts VV and VVa were intended to adjust the 
replacement cost for inflation to approximate the original cost basis; 
however, the formulas were based on analysis of inflation between the 
years 1947 and 1982 and do not necessarily reflect current economic 
conditions. In the 2020 amendments to NSPS subpart OOOOa, which covers 
the oil and natural gas sector, the EPA determined that using a CPI-
based ratio is more appropriate under current economic conditions.\56\ 
Similarly, the EPA has determined the CPI-based ratio better reflects 
the inflation of chemical process facility construction costs over time 
and thus is more appropriate for use in determining capital expenditure 
for the SOCMI source category in NSPS subpart VVb. There are several 
versions of the CPI published by the U.S. Bureau of Labor Statistics; 
for simplicity, the EPA is requiring the use of ``CPI-U, U.S. city 
average, all items'' (CPI for all urban consumers) for both CPI values.
---------------------------------------------------------------------------

    \56\ See Office of Air Quality Planning & Standards, U.S. 
Environmental Protection Agency. Docket Item No. EPA-HQ-OAR-2017-
0483-2291, EPA Responses to Public Comments on Reconsideration of 
New Source Performance Standards (NSPS) Oil and Natural Gas Sector: 
Emission Standards for New, Reconstructed, and Modified Sources 
Reconsideration 40 CFR part 60, subpart OOOOa at 11-2 (Sep. 2020).
---------------------------------------------------------------------------

4. What is the rationale for our final approach and final decisions for 
the technology review and NSPS review?
a. NESHAP
    Our technology review focused on the identification and evaluation 
of developments in practices, processes, and control technologies that 
have occurred since the previous technology reviews for the HON and the 
P&R I and P&R II NESHAP were promulgated (see 71 FR 76603, December 21, 
2006; 73 FR 76220, December 16, 2008; and 77 FR 22566, April 21, 2011 
for additional details). Specifically, we focused our technology review 
on all existing MACT standards for the various emission sources in the 
SOCMI, P&R I, and P&R

[[Page 43016]]

II source categories, including, heat exchange systems, storage 
vessels, process vents, transfer racks, wastewater, and equipment 
leaks. Under CAA section 112(d)(6), we also proposed a fenceline 
monitoring work practice standard requiring owners and operators to 
monitor for any of six specific HAP (i.e., benzene, 1,3-butadiene, 
ethylene dichloride, vinyl chloride, EtO, and chloroprene) if their 
site uses, produces, stores, or emits any of them, and conduct root 
cause analysis and corrective action upon exceeding the annual average 
concentration action level set forth for each HAP. In the proposal, we 
identified cost-effective developments only for HON and P&R I heat 
exchange systems, storage vessels, and process vents, and we proposed 
to revise the standards for these three emissions sources under the 
technology review. We did not identify developments in practices, 
processes, or control technologies (beyond the fenceline monitoring 
work practice standard) for transfer racks, wastewater, and equipment 
leaks. Further information regarding the technology review can be found 
in the proposed rule (88 FR 25080, April 25, 2023) and in the 
supporting materials in the rulemaking docket at Docket ID No. EPA-HQ-
OAR-2022-0730.
    During the public comment period, we received several comments on 
our proposed determinations for the technology review. The comments and 
our specific responses and rationale for our final decisions can be 
found in section IV.B.3 of this preamble and in the document titled 
Summary of Public Comments and Responses for New Source Performance 
Standards for the Synthetic Organic Chemical Manufacturing Industry and 
National Emission Standards for Hazardous Air Pollutants for the 
Synthetic Organic Chemical Manufacturing Industry and Group I & II 
Polymers and Resins Industry, which is available in the docket for this 
rulemaking. No information presented by commenters has led us to change 
our proposed determination under CAA section 112(d)(6) for transfer 
racks, wastewater, and equipment leaks, and we are finalizing our 
determination that no changes to these standards are warranted. 
However, based on comments received on the proposed revisions for the 
Group 1 HON and P&R I storage vessels, we are clarifying that the 
capacity and MTVP thresholds in the final rule apply to both new and 
existing sources. In addition, some additional cost information was 
submitted by commenters on the proposed revisions for HON process vents 
and P&R I continuous front-end process vents. Based on these comments, 
we have updated our cost analysis, but continue to believe our 
revisions for HON process vents and P&R I continuous front-end process 
vents, as proposed, are still cost-effective. Therefore, for HON 
process vents and P&R I continuous front-end process vents, we are 
finalizing, as proposed the: (1) Removal of the TRE concept in its 
entirety; (2) removal of the 50 ppmv and 0.005 scmm Group 1 process 
vent thresholds; and (3) redefining of a Group 1 process vent (require 
control) as any process vent that emits >=1.0 lb/hr of total organic 
HAP. Finally, based on comments received on the proposed fenceline 
monitoring requirements, we have established two action levels in the 
final rule for chloroprene (i.e., one action level under CAA section 
112(d)(6) for this HAP and another action level under CAA section 
112(f)) in lieu of only one action level, as proposed). In addition, 
based on comments received, we are: (1) Finalizing burden reduction 
measures to allow owners and operators to skip fenceline measurement 
periods for specific monitors with a history of measurements that are 
at or below certain action levels; (2) clarifying that fenceline 
monitoring is required for owners and operators with affected sources 
that produce, store, or emit one or more of the target analytes; (3) 
reducing the requirements for the minimum detection limit of 
alternative measurement approaches; (4) clarifying how owners and 
operators establish the monitoring perimeter for both sorbent tubes and 
canisters; (5) clarifying the calculation of [Delta]c when a site-
specific monitoring plan is used to correct monitoring location 
concentrations due to offsite impacts; (6) changing the required method 
detection limit for alternative test methods from an order of magnitude 
below the action level to one-third of the action level; and (4) with 
the exception of fenceline monitoring of chloroprene at P&R I affected 
sources producing neoprene, we are changing the compliance date in the 
final rule to begin fenceline monitoring 2 years (instead of 1 year, as 
proposed) after the effective date of the final rule. For P&R I 
affected sources producing neoprene, we have changed the compliance 
date for fenceline monitoring of chloroprene to begin no later than 
October 15, 2024, or upon startup, whichever is later, subject to the 
owner or operator seeking the EPA's authorization of an extension of up 
to 2 years from July 15, 2024.
b. NSPS
    For NSPS subparts IIIa, NNNa, and RRRa, we are finalizing the suite 
of process vent requirements, as proposed.\57\ As described in the 
proposal (88 FR 25080, April 25, 2023) and in consideration of comments 
received about these new requirements (see section IV.B.3.b.i of this 
preamble for further detail), we found the requirements to be cost-
effective for VOC emission reductions at new, modified, and 
reconstructed affected facilities.
---------------------------------------------------------------------------

    \57\ See section IV.B.1.b.i of this preamble.
---------------------------------------------------------------------------

    For NSPS subpart VVb, we are finalizing, as proposed, the same 
requirements in NSPS subpart VVa with the updated requirement that all 
gas/vapor and light liquid valves be monitored monthly at a leak 
definition of 100 ppm instead of 500 ppm, and an additional requirement 
that all connectors be monitored once every 12 months at a leak 
definition of 500 ppm, as described in the proposal (88 FR 25080, April 
25, 2023).

C. Amendments Pursuant to CAA Section 112(d)(2) and (3) and 112(h) for 
the SOCMI, P&R I, and P&R II Source Categories NESHAP

1. What did we propose pursuant to CAA section 112(d)(2) and (3) and 
112(h) for the SOCMI, P&R I, and P&R II source categories?
    Under CAA sections 112(d)(2) and (3), we proposed to amend the 
operating and monitoring requirements for a subset of flares in the 
SOCMI and P&R I source categories. We proposed at 40 CFR 63.108 (for 
HON) and 40 CFR 63.508 (for the P&R I NESHAP) to directly apply the 
petroleum refinery flare rule requirements in 40 CFR part 63, subpart 
CC, to the HON and P&R I flares with clarifications, including, but not 
limited to, specifying that several definitions in 40 CFR part 63, 
subpart CC, that apply to petroleum refinery flares also apply to the 
flares in the specified subset, adding a definition and requirements 
for pressure-assisted multi-point flares, and specifying additional 
requirements when a gas chromatograph or mass spectrometer is used for 
compositional analysis. Specifically, we proposed to retain the General 
Provisions requirements of 40 CFR 63.11(b) and 40 CFR 60.18(b) such 
that HON and P&R I flares operate pilot flame systems continuously and 
that these flares operate with no visible emissions (except for periods 
not to

[[Page 43017]]

exceed a total of 5 minutes during any 2 consecutive hours) when the 
flare vent gas flow rate is below the smokeless capacity of the flare. 
We also proposed to consolidate measures related to flare tip velocity 
and new operational and monitoring requirements related to the 
combustion zone gas for HON and P&R I flares. Further, in keeping with 
the elimination of the SSM exemption, we proposed a work practice 
standard related to the visible emissions limits during periods when a 
HON or P&R I flare is operated above its smokeless capacity (e.g., 
periods of emergency flaring). We proposed eliminating the cross-
references to the General Provisions and instead specifying all 
operational and monitoring requirements that are intended to apply to 
HON and P&R I flares in the applicable subparts.
    In addition, we proposed provisions and clarifications in the HON 
and P&R I and P&R II NESHAP for periods of SSM and bypasses, including 
PRD releases, bypass lines on closed vent systems, maintenance vents 
and equipment openings, storage vessel degassing, and planned routine 
maintenance for storage vessels to ensure that CAA section 112 
standards apply continuously, consistent with Sierra Club v. EPA 551 F. 
3d 1019 (D.C. Cir. 2008).
    For PRD releases, we proposed revisions to the definition of 
``pressure relief device'' for the HON and P&R I NESHAP, a definition 
of ``relief valve'' for the HON and P&R I NESHAP, and a definition in 
the P&R II NESHAP for ``pressure relief device.'' Under CAA section 
112(h), we proposed a work practice standard for PRDs at 40 CFR 
63.165(e) (for HON) and 40 CFR 63.502(a)(1) and (a)(2) (which 
references 40 CFR 63.165, for the P&R I NESHAP) that consists of using 
at least three prevention measures and performing root cause analysis 
and corrective action in the event that a PRD does release emissions 
directly to the atmosphere.\58\ (Examples of prevention measures 
include flow indicators, level indicators, temperature indicators, 
pressure indicators, routine inspection and maintenance programs or 
operator training, inherently safer designs or safety instrumentation 
systems, deluge systems, and staged relief systems where the initial 
PRD discharges to a control system.) We proposed that PRDs in EtO 
service (for HON) and PRDs in chloroprene service (for Neoprene 
Production processes subject to the P&R I NESHAP) may not vent directly 
to atmosphere. We also proposed to require that sources monitor PRDs 
that vent to atmosphere using a system that is capable of identifying 
and recording the time and duration of each pressure release and of 
notifying operators that a pressure release has occurred. We proposed 
at 40 CFR 63.165(e)(4) that PRDs that vent through a closed vent system 
to a control device or to a process, fuel gas system, or drain system 
must meet minimum requirements for the applicable control system. In 
addition, we proposed at 40 CFR 63.165(e)(5) that the following types 
of PRDs would not be subject to the work practice standard for PRDs 
that vent to the atmosphere: (1) PRDs in heavy liquid service; (2) PRDs 
that are designed solely to release due to liquid thermal expansion; 
(3) PRDs on mobile equipment; and (4) pilot-operated and balanced 
bellows PRDs if the primary release valve associated with the PRD is 
vented through a control system. Finally, we proposed at 40 CFR 
63.165(e)(8) to require future installation and operation of non-
flowing pilot-operated PRDs at all affected sources.
---------------------------------------------------------------------------

    \58\ The P&R II NESHAP is different from the HON and the P&R I 
NESHAP because the P&R II NESHAP defines a process vent as a ``a 
point of emission from a unit operation. Typical process vents 
include condenser vents, vacuum pumps, steam ejectors, and 
atmospheric vents from reactors and other process vessels.'' As 
such, the P&R II NESHAP does not exclude PRD releases from its 
production-based emission rate MACT standard.
---------------------------------------------------------------------------

    For bypass lines on closed vent systems, we proposed at 40 CFR 
63.114(d)(3), 40 CFR 63.127(d)(3), 40 CFR 63.148(f)(4), and 40 CFR 
63.172(j)(4) (for HON), and 40 CFR 63.485(x), 40 CFR 63.489(d)(3), and 
40 CFR 63.502(a)(2) (for the P&R I NESHAP) that an owner or operator 
may not bypass the APCD at any time, that a bypass is a violation (at 
40 CFR 63.118(a)(5) and (f)(7), 40 CFR 63.130(a)(2)(iv), (b)(3), and 
(d)(7), 40 CFR 63.148(i)(3)(iii) and (j)(4), Tables 3, 7, and 20 to 40 
CFR 63, subpart G, 40 CFR 63.181(g)(3)(iii), and 40 CFR 63.182(d)(xix) 
(for HON), and 40 CFR 63.485(x), 40 CFR 63.489(d)(3), and 40 CFR 
63.502(a)(2) (for the P&R I NESHAP)), and the owner or operator must 
estimate and report the quantity of organic HAP released.
    Under CAA section 112(h), we proposed a work practice standard for 
maintenance vents and equipment openings at 40 CFR 63.113(k)(1)(i) (for 
HON), and at 40 CFR 63.485(x) and 40 CFR 63.487(i)(1)(i) (for the P&R I 
NESHAP) requiring that, prior to opening process equipment to the 
atmosphere, the equipment must either (1) be drained and purged to a 
closed system so that the hydrocarbon content is less than or equal to 
10 percent of the LEL; (2) be opened and vented to the atmosphere only 
if the 10-percent LEL cannot be demonstrated and the pressure is less 
than or equal to 5 psig, provided there is no active purging of the 
equipment to the atmosphere until the LEL criterion is met; (3) be 
opened when there is less than 50 lbs of VOC that may be emitted to the 
atmosphere; or (4) for installing or removing an equipment blind, 
depressurize the equipment to 2 psig or less and maintain pressure of 
the equipment where purge gas enters the equipment at or below 2 psig 
during the blind flange installation, provided none of the other 
proposed work practice standards can be met.
    Also under CAA section 112(h), we proposed a work practice standard 
for storage vessel degassing at 40 CFR 63.119(a)(6) (for HON) and 40 
CFR 63.484(a) and (t) (which references 40 CFR 63.119, for the P&R I 
NESHAP) to allow storage vessels to be vented to the atmosphere once a 
storage vessel degassing concentration threshold is met (i.e., once the 
vapor space concentration is less than 10 percent of the LEL) and all 
standing liquid has been removed from the vessel to the extent 
practicable. In addition, we proposed at 40 CFR 63.119(e)(7) that 
owners and operators would not be permitted to fill the storage vessel 
during these periods (such that the vessel would emit HAP to the 
atmosphere for a limited amount of time due to breathing losses only).
    To address regulatory gaps, we proposed:
    Emission limits for dioxins and furans at 40 CFR 63.113(a)(5) (for 
HON), 40 CFR 63.485(x) and 40 CFR 63.487(a)(3) and (b)(3) (for the P&R 
I NESHAP), and 40 CFR 63.523(e), 40 CFR 63.524(a)(3), and 40 CFR 
63.524(b)(3) (for the P&R II NESHAP).
    To define pressure vessel at 40 CFR 63.101 (for HON) and 40 CFR 
63.482 (for the P&R I NESHAP) to mean ``a storage vessel that is used 
to store liquids or gases and is designed not to vent to the atmosphere 
as a result of compression of the vapor headspace in the pressure 
vessel during filling of the pressure vessel to its design capacity,'' 
and to remove the exemption for ``pressure vessels designed to operate 
in excess of 204.9 kilopascals and without emissions to the 
atmosphere'' from the definition of storage vessel. We proposed LDAR 
requirements at 40 CFR 63.119(a)(7) (for HON) and 40 CFR 63.484(t) (for 
the P&R I NESHAP) requiring no detectable emissions at all times (i.e., 
would be required to meet a leak definition of 500 ppm at each point on 
the pressure vessel where total

[[Page 43018]]

organic HAP could potentially be emitted); initial and annual leak 
monitoring using EPA Method 21 of 40 CFR part 60, Appendix A-7; and 
routing organic HAP through a closed vent system to a control device 
(i.e., no releases to the atmosphere through a pressure vessel's PRD).
    A requirement at 40 CFR 63.170(b) (for HON) and 40 CFR 63.485(d) 
(for the P&R I NESHAP) that owners and operators of all surge control 
vessels and bottoms receivers that emit greater than or equal to 1.0 
lb/hr of total organic HAP would be required to reduce emissions of 
organic HAP using a flare meeting the proposed operating and monitoring 
requirements for flares; or reduce emissions of total organic HAP or 
TOC by 98 percent by weight or to an exit concentration of 20 ppmv.
    Removing the exemption for transfer operations that load ``at an 
operating pressure greater than 204.9 kilopascals'' from the definition 
of transfer operation at 40 CFR 63.101 (for HON) such that owners and 
operators would be required to equip each transfer rack with an 
operating pressure greater than 204.9 kilopascals with a vapor 
collection system and control device to reduce total organic HAP 
emissions by 98 percent by weight or to an exit concentration of 20 
ppmv.
    Requirements at 40 CFR 63.523(d) (for BLR manufacturers subject to 
the P&R II NESHAP) and 40 CFR 63.524(c) (for WSR manufacturers subject 
to the P&R II NESHAP) that owners and operators of each affected source 
comply with the requirements of 40 CFR 63.104 for heat exchange 
systems, including quarterly monitoring for existing and new heat 
exchange systems (after an initial 6 months of monthly monitoring) 
using the Modified El Paso Method and a leak definition of 6.2 ppmv of 
total strippable hydrocarbon concentration (as methane) in the 
stripping gas. We also proposed at 40 CFR 63.104(j)(3) a delay of 
repair action level of total strippable hydrocarbon concentration (as 
methane) in the stripping gas of 62 ppmv, that if exceeded during leak 
monitoring, would require immediate repair (i.e., the leak found cannot 
be put on delay of repair and would be required to be repaired within 
30 days of the monitoring event). In addition, we proposed at 40 CFR 
63.104(h) and (i) re-monitoring at the monitoring location where a leak 
is identified to ensure that any leaks found are fixed. Finally, we 
proposed that none of these requirements would apply to heat exchange 
systems that have a maximum cooling water flow rate of 10 gallons per 
minute or less.
    A requirement at 40 CFR 63.524(a)(3) and (b)(3) that owners and 
operators of existing, new, or reconstructed affected WSR sources 
subject to the P&R II NESHAP comply with both the equipment leak 
standards in the HON and the HAP emissions limitation for process 
vents, storage tanks, and wastewater systems (i.e., we proposed that 
the alternative standard is no longer optional). For the P&R II NESHAP, 
we also proposed to include valves in the definition of ``equipment 
leaks'' at 40 CFR 63.522 such that owners and operators of an existing, 
new, or reconstructed affected BLR or WSR source would be required to 
comply with the same LDAR program that already exists in the HON and 
the P&R I NESHAP for valves that contain or contact material that is 5 
percent by weight or more of organic HAP, operate 300 hours per year or 
more, and are not in vacuum service.
    A requirement at 40 CFR 63.119(b)(7), that owners and operators 
that use a sweep, purge, or inert blanket between the IFR and fixed 
roof of a storage vessel would be required to route emissions through a 
closed vent system and control device.
    We proposed that all of these requirements (proposed for the 
purpose of addressing regulatory gaps) are consistent with CAA section 
112(d) controls and reflect the MACT floor, and we did not identify any 
additional options beyond these (i.e., beyond-the-floor options) for 
controlling emissions from these emission sources. More information 
concerning our proposed requirements under CAA section 112(d)(2) and 
(3) and 112(h) can be found in sections III.D and III.E of the proposal 
preamble (88 FR 25080, April 25, 2023).
2. How did the revisions pursuant to CAA section 112(d)(2) and (3) and 
112(h) change since proposal?
    The EPA is finalizing the work practice standard for storage vessel 
degassing, as proposed, except that we are adding an option at 40 CFR 
63.119(a)(6) to allow owners and operators to degas a storage vessel to 
the atmosphere once a vapor space organic HAP concentration of less 
than 5,000 ppmv as methane is met (in lieu of having to meet a vapor 
space concentration threshold of less than 10 percent of the LEL). We 
are also correcting our use of the term ``LEL'' versus our use of the 
term ``concentration'' in 40 CFR 63.119(a)(6) in that ``the 
concentration'' of the vapors in storage vessels be less than 10 
percent of the LEL and that owners and operators are required to 
measure ``the concentration'' of the vapors as a percent of the LEL. We 
are also revising the final rule at 40 CFR 63.119(a)(6) to include 
storage vessels in EtO service subject to 40 CFR 63.119(a)(5).
    The EPA is finalizing the revisions to the work practice standard 
for planned routine maintenance of storage vessels, as proposed, except 
that we are clarifying in the final rule at 40 CFR 63.119(f)(3) that 
the 240-hour planned routine maintenance provisions also apply for 
breathing losses for fixed rood roof vessels routed to a fuel gas 
system or to a process.
    The EPA is finalizing the requirements for pressure vessels, as 
proposed, except that we are: (1) Clarifying that the pressure vessel 
requirements at 40 CFR 63.119(a)(7) only apply to pressure vessels that 
are considered Group 1 storage vessels; (2) clarifying that if the 
equipment is not a connector, gas/vapor or light liquid valve, light 
liquid pump, or PRD in EtO service and the equipment is on a pressure 
vessel located at a HON or P&R I facility, then that particular 
equipment is not subject to HON subpart H, but rather the equipment is 
subject to the pressure vessel requirements we proposed and are 
finalizing in 40 CFR 63.119(a)(7); (3) clarifying that unsafe and 
difficult/inaccessible to monitor provisions in 40 CFR 63.168(h) and 
(i) (for valves in gas/vapor service and in light liquid service) and 
in 40 CFR 63.174(f) and (h) (for connectors in gas/vapor service and in 
light liquid service) still apply to valves and connectors when 
complying with 40 CFR 63.119(a)(7); and (4) replacing the word 
``deviation'' with ``violation'' in the final rule text at 40 CFR 
63.119(a)(7).
    The EPA is finalizing the requirements for surge control vessels 
and bottoms receivers, as proposed, except that we are adding language 
in the ``C'' and ``Q'' terms of the equations at 40 CFR 
63.115(g)(3)(ii) and (g)(4)(iv) to allow the use of engineering 
calculations to determine concentration or flow rate only in situations 
where measurements cannot be taken with EPA reference methods. We are 
also adding reference methods for measuring flow rate at 40 CFR 
63.115(g)(3)(ii) and 40 CFR 63.115(g)(4)(iv).
    Also, we are clarifying in the final rule that the requirements for 
sweep, purge, and inert blankets from IFRs at 40 CFR 63.119(b)(7) 
applies only if a continuous sweep, purge, or inert blanket is used 
between the IFR and fixed roof that causes a pressure/vacuum vent to 
remain continuously open to the atmosphere where uncontrolled emissions 
are greater than

[[Page 43019]]

or equal to 1.0 lb/hr of total organic HAP.
3. What key comments did we receive on the proposal revisions pursuant 
to CAA section 112(d)(2) and (3) and 112(h), and what are our 
responses?
    This section provides summaries of and responses to the key 
comments received regarding our proposed revisions for periods of SSM, 
including maintenance vents and equipment openings, storage vessel 
degassing, planned routine maintenance of storage vessels, pressure 
vessels, surge control vessels and bottoms receivers, and the 
requirements for sweep, purge, and inert blankets from IFRs. Other 
comment summaries and the EPA's responses for additional issues raised 
regarding these activities, as well as issues raised regarding our 
proposed revisions for flares, PRDs, bypass lines on closed vent 
systems, emission limits for dioxins and furans, transfer operations 
(for HON), heat exchange systems (for the P&R II NESHAP), and equipment 
leaks (for the P&R II NESHAP) can be found in the document titled 
Summary of Public Comments and Responses for New Source Performance 
Standards for the Synthetic Organic Chemical Manufacturing Industry and 
National Emission Standards for Hazardous Air Pollutants for the 
Synthetic Organic Chemical Manufacturing Industry and Group I & II 
Polymers and Resins Industry, which is available in the docket for this 
rulemaking.
a. Maintenance Vents
    Comment: Commenters contended that the EPA misuses the term LEL for 
the maintenance vents and storage vessel degassing provisions. A 
commenter said that the regulatory language implies that operators have 
the ability to change the LEL of a vapor by purging or otherwise 
removing portions of the vapor from equipment. This commenter said that 
the concentration of a flammable gas or mixture can be lowered (e.g., 
by dilution or displacement) to a level that is less than the LEL; 
thus, they requested that the EPA clarify that concentration of the 
vapors in equipment be less than 10 percent of the LEL and that 
facilities are to measure the vapor concentration, not the LEL. 
Similarly, another commenter requested that the EPA clarify that the 
concentration of the vapors in equipment and storage vessels be less 
than 10 percent of the LEL and that facilities are to measure the 
concentration of the vapors as a percent of the LEL (i.e., with a hand-
held analyzer that reports concentration as a percent of LEL, and not 
the LEL itself). The commenter suggested that these changes should be 
made to 40 CFR 63.113(k), 40 CFR 63.118(f) and (m), 40 CFR 
63.119(a)(6), 40 CFR 63.486(i), 40 CFR 63.491(h), and 40 CFR 63.492(g). 
The commenter provided an example saying that in proposed 40 CFR 
63.119(a)(6), the second instance of ``LEL'' should be corrected to 
read ``The owner or operator must determine the concentration using 
process instrumentation or portable measurement devices . . .''.
    Response: We agree with the commenters that our proposed use of the 
term LEL improperly implies that operators have the ability to change 
the LEL of a vapor by purging or otherwise removing portions of the 
vapor from equipment. In the final rule, we are revising 40 CFR 
63.113(k)(1)(i) and (ii) and (k)(2), 40 CFR 63.119(a)(6), 40 CFR 
63.118(f)(9)(iii) and (m)(2), (3), and (5), 40 CFR 63.486(i)(1)(i) and 
(ii) and (i)(2), 40 CFR 63.491(h)(2), (3), and (5), and 40 CFR 
63.492(g)(3) to clarify that ``the concentration'' of the vapors in 
equipment and storage vessels be less than 10 percent of the LEL and 
that facilities are to measure ``the concentration'' of the vapors as a 
percent of the LEL.
b. Storage Vessel Degassing
    Comment: Several commenters supported the proposed degassing 
provisions at 40 CFR 63.119(a)(6). However, some commenters requested 
the EPA also add a concentration limit as an alternative to LEL 
measurements. The commenters explained that some nonflammable chemicals 
do not exhibit an LEL, or through the use of an inert blanket, the 
storage vessel atmosphere would not have an LEL, so owners and 
operators of storage vessels under these conditions would be unable to 
comply with the proposed 10 percent LEL threshold. These commenters 
requested that the EPA allow the storage vessel to be opened after the 
vapor space organic HAP content has been reduced below 5,000 ppmv, 
based on the Agency's assertion that this level is equivalent to 10 
percent of the LEL. A commenter pointed out that 5,000 ppmv as methane 
equals 10 percent of the LEL for methane.
    Response: We agree with commenters that some nonflammable chemicals 
do not exhibit an LEL, or through the use of an inert blanket, the 
storage vessel atmosphere would not have an LEL, so owners and 
operators of storage vessels under these conditions would be unable to 
comply with the proposed 10 percent LEL threshold. Therefore, we are 
revising the final rule at 40 CFR 63.119(a)(6) to allow storage vessels 
to be vented to the atmosphere once a storage vessel degassing organic 
HAP concentration of 5,000 ppmv as methane is met, or until the vapor 
space concentration is less than 10 percent of the LEL. We stated in 
the preamble to the proposed rule (88 FR 25080, April 25, 2023) that we 
are aware of three regulations regarding storage vessel degassing, two 
in the state of Texas and the third for the South Coast Air Quality 
Management District (SCAQMD) in California. Texas has degassing 
provisions in the TAC and through permit conditions, while Rule 1149 
contains the SCAQMD degassing provisions. The TAC requirements are the 
least stringent and require control of degassing emissions until the 
vapor space concentration is less than 35,000 ppmv as methane or 50 
percent of the LEL. The Texas permit conditions require control of 
degassing emissions until the vapor space concentration is less than 10 
percent of the LEL or until the VOC concentration is less than 10,000 
ppmv, and SCAQMD Rule 1149 requires control of degassing emissions 
until the vapor space concentration is less than 5,000 ppmv as methane. 
The Texas permit conditions requiring compliance with 10 percent of the 
LEL and SCAQMD Rule 1149 control requirements are considered equivalent 
because 5,000 ppmv as methane equals 10 percent of the LEL for methane.
    Comment: A commenter remarked that the work practice standard 
proposed in 40 CFR 63.119(a)(6) should not only apply to degassing 
Group 1 storage vessels, but should also be applicable for degassing 
storage vessels in EtO service. The commenter explained that a storage 
vessel in EtO service (subject to 40 CFR 63.119(a)(5)) may also need to 
be degassed during storage vessel shutdown operations, but the way the 
proposed language is currently written, the storage vessel degassing 
provisions only apply to storage vessels subject to 40 CFR 63.119(a)(1) 
and (a)(2). The commenter requested the EPA amend the language in 40 
CFR 63.119(a)(6) to include storage vessels in EtO service subject to 
40 CFR 63.119(a)(5).
    Response: It was not our intent to exclude storage vessels in EtO 
service from the work practice standard in 40 CFR 63.119(a)(6); 
therefore, we are revising the final rule at 40 CFR 63.119(a)(6) to 
include storage vessels in EtO service subject to 40 CFR 63.119(a)(5). 
However, owners and operators are still prohibited from releasing more 
than 1.0 ton of EtO from all maintenance vents combined in any 
consecutive 12-month period at 40 CFR 63.113(k)(4). In other words, we 
still

[[Page 43020]]

consider degassing a storage vessel a type of maintenance vent. As 
stated in the final rule (as proposed), an owner or operator may 
designate any vent stream as a maintenance vent if the vent is only 
used as a result of startup, shutdown, maintenance, or inspection of 
equipment where equipment is emptied, depressurized, degassed, or 
placed into service.
c. Planned Routine Maintenance for Storage Vessels
    Comment: A commenter said they supported the proposed work practice 
standard for periods of planned routine maintenance for storage vessels 
including the proposed requirement that owners and operators would not 
be permitted to fill storage vessels during these periods. However, 
another commenter pointed out that the 240-hour planned routine 
maintenance provisions at 40 CFR 63.119(f)(3) (for fixed rood roof 
vessels routed to a fuel gas system or to a process) is inconsistent 
with the parallel requirement at 40 CFR 63.119(e)(7) for fixed rood 
roof vessels routed to a control device. The commenter requested the 
EPA make 40 CFR 63.119(f)(3)(iii) no longer apply on or after the 
compliance dates specified in 40 CFR 63.100(k)(10) and allow for, in a 
new paragraph at 40 CFR 63.119(f)(3)(iv), the 240-hour planned routine 
maintenance provisions for breathing losses for fixed rood roof vessels 
routed to a fuel gas system or to a process. Citing page 25161 of the 
preamble to the proposed rule (88 FR 25080, April 25, 2023), the 
commenter contended that this recommended change for fixed rood roof 
vessels routed to a fuel gas system or to a process would be consistent 
with the proposed rule text at 40 CFR 63.119(e)(7) for fixed rood roof 
vessels routed to a control device. The commenter added that their 
recommendation is also similar to the approach that the EPA used in the 
Organic Liquids Distribution MACT (NESHAP subpart EEEE) under 40 CFR 
63.2378(d) and (e)(4). The commenter pointed out that the associated 
recordkeeping requirement in 40 CFR 63.123(h) would also need to be 
amended slightly to reference the new recommended paragraph at 40 CFR 
63.119(f)(3)(iv).
    Response: We agree with the commenter that the 240-hour planned 
routine maintenance provisions should apply for breathing losses for 
fixed rood roof vessels routed to a fuel gas system or to a process 
given this would parallel the requirement at 40 CFR 63.119(e)(7). 
Therefore, we are revising the final rule to sunset 40 CFR 
63.119(f)(3)(iii) in accordance with the schedule specified in 40 CFR 
63.100(k)(10), and to include a new paragraph at Sec.  
63.119(f)(3)(iv). We are also revising the final rule at 40 CFR 
63.123(h)(3) to reference ``Sec.  63.119(f)(3)(iv)'' instead of ``Sec.  
63.119(f)(3)(iii).'' Additionally, we are revising 40 CFR 63.100(k)(10) 
to reference ``Sec.  63.119(f)(3)(iv)'' as well as the introductory 
text in 40 CFR 63.119(f)(3) to properly reference the new paragraph at 
``Sec.  63.119(f)(3)(iv).'' The new paragraph at 40 CFR 
63.119(f)(3)(iv) reads: ``For each source as defined in Sec.  63.101, 
beginning no later than the compliance dates specified in Sec.  
63.100(k)(10), paragraph (f)(3)(iii) of this section no longer applies. 
Instead, if you elect to route emissions from storage vessels to a fuel 
gas system or to a process to comply with the requirements of paragraph 
(a)(1), (a)(2), or (a)(5) of this section, the fuel gas system or 
process may only be bypassed when the planned routine maintenance 
cannot be performed during periods that storage vessel emissions are 
vented to the fuel gas system or process, and the total aggregate 
amount of time during which the breathing loss emissions bypass the 
fuel gas system or process during the calendar year without being 
routed to a control device must not exceed 240 hours. The level of 
material in the storage vessel shall not be increased during periods 
that the fuel gas system or process is bypassed to perform routine 
maintenance.''
d. Pressure Vessels
    Comment: Some commenters requested that the EPA clarify what is 
meant by the requirement to monitor ``each point on a pressure vessel 
at Sec.  63.119(a)(7)(ii).'' These commenters contested that components 
such as valves, pumps, and flanges servicing a pressure vessel and that 
are already subject to LDAR program requirements should be excluded 
from these provisions.
    A commenter added that PRDs associated with pressure vessels should 
be eligible to comply with the EPA's proposed PRD work practice 
standards in 40 CFR 63.165(e) and a release of total organic HAP to the 
atmosphere through a pressure vessel's PRD should not be considered a 
deviation per 40 CFR 63.119(a)(7)(v). The commenter explained that PRDs 
associated with larger pressure vessels, such a pressure sphere, are 
typically designed for very rare scenarios like a fire protection case, 
and thus venting flammable vapors vertically upward to the atmosphere 
is a safety feature. The commenter said that many engineering design 
issues will need to be evaluated before routing PRDs associated with 
specific pressure vessels to a collection system and control device, 
such as the potential for back-pressure on the collection header if 
multiple pressure vessels are included, and the potential for rapidly 
changing pressures and temperatures that may warrant special designs 
for the collection header and emission control equipment.
    Response: It was our intent that if the equipment is not a 
connector, gas/vapor or light liquid valve, light liquid pump, or PRD 
in EtO service and the equipment is on a pressure vessel located at a 
HON or P&R I facility, then that particular equipment is not subject to 
HON subpart H, but rather the equipment is subject to the pressure 
vessel requirements we proposed and are finalizing in 40 CFR 
63.119(a)(7). Connectors, gas/vapor or light liquid valves, light 
liquid pumps, and PRDs in EtO service located on a pressure vessel at a 
HON facility are still subject to HON subpart H; and we are clarifying 
this in the final rule at 40 CFR 63.119(a)(7). As we stated in the 
preamble to the proposed rule (88 FR 25080, April 25, 2023), the LDAR 
requirements at 40 CFR 63.119(a)(7) (for HON) and 40 CFR 63.484(t) (for 
the P&R I NESHAP) are based on similar no-detectable emission 
requirements required for closed vent systems in most chemical sector 
NESHAP. The intent of this language is to impose a standard that 
requires no detectable emissions at all times (i.e., would be required 
to meet a leak definition of 500 ppm at each point on the pressure 
vessel where total organic HAP could potentially be emitted); require 
initial and annual leak monitoring using EPA Method 21; and require 
routing organic HAP through a closed vent system to a control device 
(i.e., no releases to the atmosphere through a pressure vessel's PRD). 
Most pressure vessels have relief devices that allow for venting when 
pressure exceeds setpoints. There are also instances where other 
components in pressure systems may allow for fugitive releases because 
of leaks from fittings or cooling systems.
    We note that our use of the term ``deviation'' in the preamble to 
the proposed rule and in 40 CFR 63.119(a)(7) was an error. While the 
MON rule text uses the MON-defined term ``deviation'' to describe 
emissions events, the current HON rule text uses the term 
``violation.'' There are no uses of the term ``deviation'' to describe 
an emissions event in the current HON rule text, nor any definition of 
that term in the HON. Therefore, given that we are building off the 
existing HON standards,

[[Page 43021]]

we believe it is more appropriate to continue to use the term 
``violation'' (in lieu of the undefined term ``deviation'') in all of 
the HON rule text. We have replaced ``deviation'' with ``violation'' in 
the final rule text at 40 CFR 63.119(a)(7).
    Comment: Some commenters contended that the pressure vessel 
monitoring provisions in 40 CFR 63.119(a)(7) are not feasible for some 
tanks because the pressure vessel is not accessible to monitoring 
personnel. The commenter explained that some pressure vessels that 
store regulated chemicals are located inside containment areas or are 
partially buried such that monitoring of the vessel surface per EPA 
Method 21 is not possible. The commenter added that some pressure 
vessels are double walled tanks designed such that there is an 
additional external shell outside of the pressure vessel shell (i.e., a 
tank within a tank shell). The commenter suggested: (1) Pressure 
monitoring of the gas space (typically nitrogen) between the pressure 
vessel wall and the second exterior wall be conducted to detect a 
potential leak, and if a pressure increase occurs, then the owner or 
operator should be allowed to follow a work practice that requires that 
the leak be repaired as soon as practical; and (2) for situations where 
a pressure vessel is located inside a containment area or partially 
buried, the owner or operator should only be required to conduct EPA 
Method 21 monitoring on potential leak sources that are accessible and 
are not unsafe-to-monitor. The commenter provided suggested rule text 
edits in order to accommodate this request. Similarly, another 
commenter suggested the EPA incorporate ``unsafe-to-monitor'' and 
``inaccessible'' provisions at 40 CFR 63.119(a)(7) similar to those in 
other sections of NESHAP subpart H and in NESHAP subpart UU because 
some pressure vessels are located in concrete containment areas, are 
partially buried, or are otherwise inaccessible for safety purposes. 
This commenter pointed out that the EPA did not consider costs for 
facilities to relocate or install new pressure vessels to make them 
accessible in order to comply with the proposed requirements.
    Response: It was our intent that unsafe and difficult/inaccessible 
to monitor provisions in 40 CFR 63.168(h) and (i) (for valves in gas/
vapor service and in light liquid service) and in 40 CFR 63.174(f) and 
(h) (for connectors in gas/vapor service and in light liquid service) 
still apply to valves and connectors when complying with 40 CFR 
63.119(a)(7). We are clarifying this in the final rule at 40 CFR 
63.119(a)(7)(ii).
    Comment: A commenter pointed out that the proposed pressure vessel 
requirements in 40 CFR 63.119(a)(7) appear to apply to any pressure 
vessel to which NESHAP subpart G applies. The commenter argued that 
these requirements should only apply to Group 1 storage vessels that 
are pressure vessels. The commenter explained that with the removal of 
the pressure vessel exclusion from the storage vessel definition in 40 
CFR 63.101 and the addition of the pressure vessel requirements in 40 
CFR 63.119(a)(7), the EPA may have inadvertently applied the proposed 
pressure vessel requirements to all pressure vessels, regardless of 
whether the pressure vessel is Group 1 or Group 2 or whether the 
storage vessel is exempt for another reason. The commenter contended 
that there is no reason that a Group 2 storage vessel (i.e., one not 
requiring control) or any other vessel that meets an exclusion in the 
storage vessel definition should be subject to the proposed operating 
standards for pressure vessels in 40 CFR 63.119(a)(7).
    Response: We agree with the commenter that 40 CFR 63.119(a)(7) 
should only apply to pressure vessels that are considered Group 1 
storage vessels (as defined in Table 5 to NESHAP subpart G for existing 
sources and Table 6 to NESHAP subpart G for new sources). Given that we 
removed the exemption for ``pressure vessels designed to operate in 
excess of 204.9 kilopascals and without emissions to the atmosphere'' 
from the definition of storage vessel in the final rule, all pressure 
vessels (not just pressure vessels operating less than or equal to 
204.9 kilopascals) are now considered storage vessels in the HON. For 
this reason, we are clarifying in the final rule that ``for each 
pressure vessel as defined in Sec.  63.101 that is considered a Group 1 
storage vessel (as defined in Table 5 of this subpart for existing 
sources and Table 6 of the subpart for new sources), you must operate 
and maintain the pressure vessel'' as specified in paragraphs 40 CFR 
63.119(a)(7)(i) through (v).
e. Surge Control Vessels and Bottoms Receivers
    Comment: A commenter requested that the EPA clarify whether the 
proposed threshold criteria for controlling surge control vessels and 
bottoms receivers (i.e., the 1.0 lb/hr total organic HAP threshold) is 
on an annual average basis or based on any intermittent emissions that 
exceed the 1.0 lb/hr emission standard.
    Response: As we stated in the preamble to the proposed rule (88 FR 
25080, April 25, 2023), emissions from surge control vessels and 
bottoms receivers are characteristic of process vents, not emissions 
from storage vessels. Our rationale for making this determination is 
that these vessels operate at process temperatures, not ambient storage 
temperatures; typically do not undergo level changes that larger 
storage vessels undergo; and are most often operated under pressure 
with and without non-condensable gases flowing into and out of them. 
The size of these vessels is also typically not correlated with 
emissions, as are storage vessels. The 1.0 lb/hr total organic HAP 
threshold is based on any continuous emissions that exceed the 1.0 lb/
hr emission standard. This is true for all Group 1 process vents. We 
are finalizing this threshold as proposed given that we found this 
threshold to be cost-effective for process vents (see our response to 
comments in section IV.B.3.a.i of this preamble for further details).
    Comment: A commenter requested that the EPA provide the option to 
use engineering calculations if measurements cannot be made using EPA 
reference methods to determine whether surge control vessels and 
bottoms receivers are required to be controlled. The commenter said 
that the vents from surge control vessels and bottoms receivers are 
configured more like small tanks than process vents and that these 
vents could be configured in a variety of ways. The commenter provided 
an example where the vent may be configured as a pressure/vacuum vent 
for which venting occurs on an intermittent basis, making it difficult 
to measure volumetric flow rate since the measurements are not made 
from a straight discharge pipe where the flow measurement device (e.g., 
a pitot tube) can be inserted.
    Response: The EPA agrees with the commenter that in certain 
situations, as a result of how surge vessels and bottoms receivers are 
configured, taking measurements utilizing EPA reference methods may not 
be possible. As a result, we are finalizing language in the ``C'' and 
``Q'' terms of the equations at 40 CFR 63.115(g)(3)(ii) and (g)(4)(iv) 
allowing the use of engineering calculations to determine concentration 
or flow rate only in situations where measurements cannot be taken with 
EPA reference methods. We anticipate that in most situations, as 
evidenced by one facility's responses to the CAA section 114 request, 
facilities will be able to take measurements from surge vessels and 
bottoms receivers as if they were process vents. In addition, the EPA

[[Page 43022]]

notes that while the commenter expressed concern about measuring flow 
rate, the proposed reference methods (EPA Method 25A or EPA Method 18) 
are utilized to measure concentration. Given it was the EPA's intent to 
provide methodology for measuring both flow rate and concentration as 
part of the proposal, we are adding reference methods for measuring 
flow rate at 40 CFR 63.115(g)(3)(ii) and 40 CFR 63.115(g)(4)(iv) by 
adding the following text to the definition of, Q, the flow rate term 
to remedy the lack of clarity: ``determined using Method 2, 2A, 2C, or 
2D of 40 CFR part 60, appendix A, as appropriate.''
f. Control of Sweep, Purge, and Inert Blankets From IFRs
    Comment: Several commenters objected to the proposed requirements 
at 40 CFR 63.119(b)(7) that would require owners and operators that use 
sweep, purge, or inert blankets between the IFR and fixed roof of 
storage vessels to route emissions through a closed vent system and 
control device. Some commenters explained that the EPA did not consider 
the cost-effectiveness of controls under CAA section 112(d)(2) when 
considering this proposal. A commenter said that most IFR storage 
vessels are equipped with a sweep, purge, or blanket and the proposed 
requirements would render these storage vessels obsolete, given that 
facilities could remove the IFR and route all emissions to a control 
device while remaining in compliance with the rule. The commenter 
acknowledged that a continuous purge of an inert blanket will result in 
higher emissions from an IFR than no purge; however, the commenter 
added that IFR storage vessels are normally not designed to hold 
pressure, and the space between the IFR and the fixed roof must vent 
somewhere when the vessel is being filled, and conversely there must be 
a mechanism to avoid a vacuum in the vessel when the vessel is being 
emptied to prevent a vessel failure. To support their objection to the 
proposed requirements at 40 CFR 63.119(b)(7), the commenter provided a 
cost analysis for this level of control that resulted in emissions 
reductions of 0.1 lb/hr of HAP per vessel, which they estimated would 
cost $190,000/yr to control and would not be cost-effective. Other 
commenters agreed with this cost analysis and stated the cost would not 
justify the additional amount of emissions reductions. These commenters 
suggested the EPA revise their analysis, and if the proposed level of 
control was found to be cost-effective, the commenters requested that 
the EPA also consider the secondary emissions (i.e., CO, 
NOX, and CO2) that would result from the 
additional fuel required to treat a stream largely comprised of inert 
gas. A commenter said that adding downstream abatement measures to IFR 
vessels will require significant structural foundations to and from, or 
between, as applicable, emission sources, air abatement controls, 
utilities, and control systems for tanks already located at relatively 
remote locations, making them more costly than otherwise similar 
ancillary equipment at locations closer to manufacturing operations. 
Finally, the commenter requested that the EPA clarify whether the 
proposed requirements apply to all vessels with a sweep, purge, or 
blanket, or only a subset, as vessels with IFRs are generally not 
designed to hold pressure, and would need to vent to avoid negative 
pressure. The commenter added that the space between the IFR and the 
fixed roof must vent somewhere when the vessel is being filled and 
conversely there must be a mechanism to avoid a vacuum in the tank when 
the vessel is being emptied to prevent a tank failure.
    Response: Installing a floating roof minimizes evaporative losses 
of the stored liquid. Both contact and noncontact decks incorporate rim 
seals and deck fittings to reduce evaporative loss of the stored 
liquid. Evaporative losses from floating roofs may come from deck 
fittings, nonwelded deck seams, and the annular space between the deck 
and vessel wall. In addition, IFRs are freely vented by circulation 
vents at the top of the fixed roof. The vents minimize the possibility 
of organic vapor accumulation in the tank vapor space in concentrations 
approaching the flammable range. An IFR vessel not freely vented is 
considered an IFR vessel with a closed vent system. Sections 7.1.3 and 
7.1.3.8.2 of EPA's AP-42, Fifth Edition,\59\ provide emission 
estimation methods for freely vented IFR vessels and IFR vessels vented 
only through a pressure/vacuum vent in the fixed roof (i.e., no open 
vents), respectively.
---------------------------------------------------------------------------

    \59\ Compilation of Air Pollutant Emission Factors. Volume 1: 
Stationary Point and Area Sources. AP-42, Fifth Edition. Chapter 7: 
Liquid Storage Tanks. Office of Air Quality Planning and Standards, 
Research Triangle Park, NC. See https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-fifth-edition-volume-i-chapter-7-liquid-storage-0.
---------------------------------------------------------------------------

    The HON allows owners or operators to choose from different options 
to control emissions from storage vessels and comply with the MACT 
standards (i.e., owners and operators can use a closed vent system and 
control device to reduce inlet emissions of total organic HAP by 95 
percent or greater, or reduce organic HAP by utilizing a fixed roof and 
IFR, an EFR, an EFR converted to an IFR, route the emissions to a 
process or a fuel gas system, or vapor balance). As such, the use of a 
floating roof that meets the requirements in 40 CFR 63.119(b) is one of 
the control options owners or operators may choose for control of 
emissions during normal storage vessel operations.
    Section 7.1 of the EPA's AP-42, Fifth Edition suggests a default 
reduction of 5 percent on total estimated emissions to account for the 
use of closed vents on an IFR. This recommendation is based on API 
Technical Report 2569 which we have determined assumes gas blanketing 
or another method is used (for IFR vessels vented only through a 
pressure/vacuum vent in the fixed roof) to prevent the development of a 
combustible gas mixture within the vessel. However, we believe that 
neither AP-42 or API Technical Report 2569 addresses the scenario where 
the use of a sweep, purge, or inert blanket between the IFR and fixed 
roof would cause a pressure/vacuum vent to remain continuously open to 
the atmosphere; and this scenario was certainly not considered during 
the development of the HON MACT standard for storage vessels. A 
pressure/vacuum vent that remains continuously open to the atmosphere 
while using a sweep, purge, or inert blanket between the IFR and fixed 
roof is effectively a continuous process vent.
    We note that in a 2021 site-specific monitoring plan submitted to 
the EPA for approval for fenceline monitoring at a refinery located in 
Corpus Christi, Texas (see Site-Specific Benzene Fenceline Monitoring 
Plan Corpus Christi Refinery East Plant Revision 2, CITGO Petroleum 
Corporation, December 1, 2021, which is available in the docket for 
this rulemaking), the company identified a slow rise in benzene 
concentration over the course of about a year. During this period, the 
company said they investigated the area for potential sources of the 
elevated benzene concentrations and completed a root cause analysis 
that identified a HON IFR storage vessel as the primary cause. The 
particular HON IFR storage vessel uses a nitrogen blanket between the 
IFR and the fixed roof to protect the storage contents from being 
contaminated with oxygen. During the investigation, the company found 
that the nitrogen regulator was malfunctioning which increased the 
pressure within the tank and ultimately released emissions to the 
atmosphere

[[Page 43023]]

(due to a small operating set point range for the nitrogen regulator 
and relief vent). Ultimately, the company addressed the elevated 
benzene concentrations by replacing the nitrogen regulator on the HON 
IFR storage vessel and routing the emissions to a liquid scrubber, 
carbon absorption system, and a vapor combustion unit. We have also 
seen other companies acknowledge similar fenceline monitoring scenarios 
where HON IFR storage vessels (with sweep, purge, or inert blanket 
between the IFR and the fixed roof of the vessel) are contributing to 
elevated benzene concentrations (see Site Specific Monitoring Plan, 
ExxonMobil Baton Rouge Refinery, September 27, 2019, which is available 
in the docket for this rulemaking).
    As such, we believe the use of a sweep, purge, or inert blanket 
between the IFR and fixed roof that would cause a pressure/vacuum vent 
to remain continuously open to the atmosphere is a regulatory gap. 
Given that continuous sweeping, purging, or blanketing between the IFR 
and the fixed roof of the vessel effectively creates a continuous 
process vent, we proposed to address this regulatory gap pursuant to 
CAA section 112(d)(2) and (3), by requiring owners and operators that 
use a sweep, purge, or inert blanket between the IFR and fixed roof of 
a storage vessel to route emissions through a closed vent system and 
control device (see 40 CFR 63.119(b)(7)). In light of the comments 
received, we are clarifying in the final rule at 40 CFR 63.119(b)(7) 
that owners and operators must route emissions through a closed vent 
system and control device if they use a continuous sweep, purge, or 
inert blanket between the IFR and fixed roof that causes a pressure/
vacuum vent to remain continuously open to the atmosphere where 
uncontrolled emissions are greater than or equal to 1.0 lb/hr of total 
organic HAP. This threshold is consistent with the definition we 
proposed and are finalizing for Group 1 process vents. These 
requirements are consistent with CAA section 112(d) controls and 
reflect the MACT floor. With regard to cost, the MACT floor is the 
minimum control level allowed for MACT standards promulgated under CAA 
section 112(d)(3), not CAA section 112(d)(2), and may not be based on 
cost considerations.
4. What is the rationale for our final approach and final decisions for 
the revisions pursuant to CAA section 112(d)(2) and (3)?
    We evaluated all of the comments on the EPA's proposed amendments 
to revisions for flares used as APCDs, clarifications for periods of 
SSM and bypasses, including PRDs, bypass lines on closed vent systems, 
and planned routine maintenance of storage vessels, and requirements 
for maintenance vents and equipment openings, storage vessel degassing, 
emission limits for dioxins and furans, pressure vessels, surge control 
vessels and bottoms receivers, sweep, purge, and inert blankets from 
IFRs, transfer operations (for HON), heat exchange systems (for the P&R 
II NESHAP), and equipment leaks (for the P&R II NESHAP). For the 
reasons explained in section III.D of the proposal preamble (88 FR 
25080, April 25, 2023), we find that the flare amendments are needed to 
ensure that flares used as APCDs achieve the required level of MACT 
control and meet 98-percent destruction efficiency at all times as well 
as to ensure that CAA section 112 standards apply at all times. 
Similarly, the clarifications for periods of SSM and bypasses, 
including PRDs, bypass lines on closed vent systems, and planned 
routine maintenance of storage vessels, and requirements for 
maintenance vents and equipment openings, storage vessel degassing, 
emission limits for dioxins and furans, pressure vessels, surge control 
vessels and bottoms receivers, sweep, purge, and inert blankets from 
IFRs, transfer operations (for HON), heat exchange systems (for the P&R 
II NESHAP), and equipment leaks (for the P&R II NESHAP) are needed to 
be consistent with Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008) 
to ensure that CAA section 112 standards apply at all times. More 
information and rationale concerning all the amendments we are 
finalizing pursuant to CAA sections 112(d)(2) and (3) is in the 
preamble to the proposed rule (88 FR 25080, April 25, 2023), in section 
IV.C.3 of this preamble, and in the comments and our specific responses 
to the comments in the document titled Summary of Public Comments and 
Responses for New Source Performance Standards for the Synthetic 
Organic Chemical Manufacturing Industry and National Emission Standards 
for Hazardous Air Pollutants for the Synthetic Organic Chemical 
Manufacturing Industry and Group I & II Polymers and Resins Industry, 
which is available in the docket for this rulemaking. Therefore, we are 
finalizing the proposed provisions for flares, finalizing the proposed 
clarifications for periods of SSM and bypasses, including PRD releases, 
bypass lines on closed vent systems, and planned routine maintenance of 
storage vessels, and finalizing standards for maintenance vents and 
equipment openings, storage vessel degassing, emission limits for 
dioxins and furans, pressure vessels, surge control vessels and bottoms 
receivers, sweep, purge, and inert blankets from IFRs, transfer 
operations (for HON), heat exchange systems (for the P&R II NESHAP), 
and equipment leaks (for the P&R II NESHAP).

D. Amendments Addressing Emissions During Periods of SSM

1. What amendments did we propose to address emissions during periods 
of SSM?
    We proposed amendments to the HON and the P&R I and P&R II NESHAP 
to remove and revise provisions related to startup, shutdown, and 
maintenance (SSM) that are not consistent with the requirement that the 
standards apply at all times. In a few instances, we are finalizing 
alternative standards for certain emission points (i.e., emergency 
flaring, PRDs, maintenance activities, and tank degassing) to minimize 
emissions during periods of SSM to ensure a continuous CAA section 112 
standard applies ``at all times'' (see section IV.C of this preamble); 
however for the majority of emission points in the SOCMI, P&R I, and 
P&R II source categories, we proposed eliminating the SSM exemptions 
and to have the emission standards apply at all times. We note that on 
April 21, 2011 (see 77 FR 22566), the EPA finalized amendments to 
eliminate the SSM exemption in the P&R I NESHAP; however, for 
consistency with the SSM related amendments that we proposed for the 
HON and P&R II NESHAP, we also proposed additional amendments to the 
P&R I NESHAP related to the SSM exemption that were not addressed in 
the April 21, 2011, P&R I rule. More information concerning the 
elimination of SSM provisions is in section III.E.1 of the proposal 
preamble (88 FR 25080, April 25, 2023).
    We also proposed to remove the affirmative defense provisions at 40 
CFR 63.480(j)(4) (for the P&R I NESHAP) to comply with the holding in 
NRDC v. EPA, 749 F.3d 1055 (D.C. Cir., 2014). More information 
concerning the removal of the affirmative defense provisions is in 
section III.E.2 of the proposal preamble (88 FR 25080, April 25, 2023).
    We proposed standards in the NSPS subparts VVb, IIIa, NNNa, and 
RRRa that apply at all times. For NSPS VVb, we proposed that the work 
practice standards will apply at all times, including during SSM. For 
NSPS subparts IIIa, NNNa, and RRRa, we proposed performance standards 
and

[[Page 43024]]

work practice standards that will apply during periods of startup and 
shutdown (including when maintenance and inspection activities are 
being conducted). Although the NSPS general provisions in 40 CFR 
60.8(c) contain an exemption from non-opacity standards, we proposed in 
NSPS subparts IIIa, NNNa, and RRRa specific requirements at 40 CFR 40 
CFR 60.612a, 40 CFR 60.662a, and 40 CFR 60.702a, respectively, that 
override the general provisions for SSM. Accordingly, we proposed NSPS 
subparts VVb, IIIa, NNNa, and RRRa would include standards that apply 
at all times, including during periods of startup and shutdown.
2. How did the SSM provisions change since proposal?
    We are finalizing the SSM provisions as proposed. We are also 
finalizing, as proposed, the removal of the provisions to assert an 
affirmative defense to civil penalties in the P&R I NESHAP at 40 CFR 
63.480(j)(4). See 88 FR 25080, April 25, 2023.
3. What key comments did we receive on the SSM revisions and what are 
our responses?
    To ensure a continuous CAA section 112 standard applies ``at all 
times'' (see section IV.C of this preamble), we are finalizing, as 
proposed, the elimination of the SSM exemptions for the SOCMI, P&R I, 
and P&R II source categories. To ensure a continuous CAA section 111 
standard applies ``at all times,'' we are finalizing, as proposed, the 
requirement that the standards in NSPS subparts VVb, IIIa, NNNa, and 
RRRa ``apply at all times, including periods of startup, shutdown and 
malfunction.'' We are also finalizing some alternative standards in 
this final rule for certain emission points during periods of SSM. This 
section provides summaries of and responses to the key comments 
received regarding our proposed requirements for PRDs at 40 CFR 
63.165(e)(3)(v)(B) and (C) and smoking flares at 40 CFR 
63.670(o)(7)(ii) and (iv) during malfunctions. Other comment summaries 
and the EPA's responses for additional issues raised regarding other 
SSM issues raised regarding our proposed revisions can be found in the 
document titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking.
    Comment: Several commenters generally supported removal of the SSM 
exemptions in the rules given it is consistent with Sierra Club v. EPA, 
551 F.3d 1019, 1028 (D.C. Cir. 2008). A commenter said that they agreed 
with the approach the EPA has taken to amend language throughout the 
HON to indicate which paragraphs or phrases no longer apply as a result 
of the proposed SSM revisions.
    Other commenters suggested that the EPA also close proposed 
loopholes for releases from PRDs at 40 CFR 63.165(e)(3)(v)(B) and (C) 
and smoking flares at 40 CFR 63.670(o)(7)(ii) and (iv) during 
malfunctions. Some of these commenters said that according to 
facilities' self-reported data, SSM emissions are often of the same 
magnitude as the facilities' reported routine emissions, and SSM 
emissions tend to spike during severe weather events. A commenter 
pointed out specific reportable quantities of emissions resulting from 
unplanned emissions events and planned SSM activities via the State of 
Texas Environmental Electronic Reporting System (STEERS). The 
commenters argued that with the properly installed and executed 
emission control systems, fail safes, backup power, maintenance 
procedures and risk management plans, emissions associated with both 
extreme weather and routine operations are preventable and should not 
be exempted from legally permitted emission limits. The commenters 
argued that the EPA erroneously concludes that the malfunction 
loopholes at 40 CFR 63.165(e)(3)(v)(B) and (C) and smoking flares at 40 
CFR 63.670(o)(7)(ii) and (iv) are reasonable.
    Commenters contended that these malfunction loopholes have real-
world, harmful effects on the health of communities surrounding these 
facilities. The commenters pointed out that the EPA readily admits, 
``[p]ressure relief events from PRDs that vent to the atmosphere have 
the potential to emit large quantities of HAPs'' and the EPA also noted 
that the majority of the Indorama Port Neches Plant's excess cancer 
risk is ``driven by EtO emissions from PRDs (74 percent).'' A commenter 
added that the EPA similarly found a ``high potential risk posed by 
chloroprene from PRD releases.'' The commenter also argued that:
     the PRD and smoking flare loopholes (at 40 CFR 
63.165(e)(3)(v)(B) and (C) and 40 CFR 63.670(o)(7)(ii) and (iv)) are 
just another variation on the original malfunction exemption and the 
affirmative defense to civil penalties, each of which the D.C. Circuit 
has found unlawful under CAA sections 302(k), 304, 113, 112(d), and 
112(f).
     the EPA's creation of these exemptions (at 40 CFR 
63.165(e)(3)(v)(B) and (C) and 40 CFR 63.670(o)(7)(ii) and (iv)) runs 
directly contrary to its own recognition in prior administrative 
practice citing the EPA's brief defending the boiler rule.
     even though the EPA included reporting and root cause 
analysis requirements, the work practice standards still constitute a 
total exemption from the core requirements for PRDs and flares during 
malfunctions of unlimited HAP release in amount and duration (in other 
words, there is no limit on the amount of HAPs emitted that applies 
during those releases allowed at 40 CFR 63.165(e)(3)(v)(B) and (C) and 
40 CFR 63.670(o)(7)(ii) and (iv)); and the EPA attempted to justify its 
original SSM exemption on similar grounds in Sierra Club v. EPA, 551 
F.3d 1019, 1028 (D.C. Cir. 2008), stating that reporting and other 
requirements still applied, but that argument failed.
     the PRD and flare loopholes (at 40 CFR 63.165(e)(3)(v)(B) 
and (C) and 40 CFR 63.670(o)(7)(ii) and (iv)) are not lawful work 
practice standards under CAA section 112(h); and even if the EPA could 
set work practice standards, CAA section 112(h) does not allow the EPA 
to avoid its obligation to enact standards that restrict emissions of 
HAPs at all times.
     the EPA has required and recognized the necessity of 
control for HON, P&R I, and MON PRDs in EtO service, P&R I PRDs in 
chloroprene service, and all Organic Liquid Distribution and P&R II 
PRDs, but has not applied equal controls to other PRDs or to flares 
above their smokeless capacity. This underscores the unlawfulness of 
the exemptions (at 40 CFR 63.165(e)(3)(v)(B) and (C) and 40 CFR 
63.670(o)(7)(ii) and (iv)), and treating these releases so differently 
is arbitrary and capricious.
    Specifically, with regards to 40 CFR 63.670(o)(7)(ii) and (iv), 
several commenters said that smoking flares produce significant amounts 
of `soot'; and beyond the health risks of particulate matter, smoking 
flares increase production of ozone, especially in the presence of 
greater environmental heat. A supporter of 40 CFR 63.670(o)(7)(ii) and 
(iv) reiterated that the provisions are necessary because the EPA is 
removing the SSM provisions. The commenter also said that they 
supported the proposal to operate in accordance with a flare management 
plan during periods when the flow to

[[Page 43025]]

the flare exceeds the smokeless capacity of the flare.
    Other supporters of 40 CFR 63.165(e)(3)(v)(B) and (C) argued that 
there should be no limit on the number of PRD releases allowed to the 
atmosphere. A commenter cited MACT standards, such as LDAR programs, 
and contended that generally these programs do not limit the number of 
leaks allowed. The commenter also added that if the EPA proceeded with 
the proposed work practice standard, then they agreed with the EPA's 
decision to allow one or two releases under the conditions set forth in 
40 CFR 63.165(e)(3)(v)(B) and (C). Commenters also requested that the 
EPA clarify that the start date for the initial three-year period for 
the limit on PRD releases to the atmosphere is the first full calendar 
year after the compliance date for the PRD work practice standard. The 
commenters further requested that the EPA include provisions that would 
not count the second event from the same equipment and same root cause 
within a 3-year period as a deviation where a) the root cause 
investigation from the first incident is not yet complete; and/or b) 
where the corrective action resulting from the root cause investigation 
requires a capital expenditure and such has been initiated and is being 
timely pursued.
    Response: The EPA acknowledges the commenters' support for removing 
the SSM exemptions in the rules. As we explained in the preamble to the 
proposed rule (88 FR 25080, April 25, 2023), in Sierra Club v. EPA, 551 
F.3d 1019 (D.C. Cir. 2008), the Court determined that the SSM exemption 
violates the CAA. Specifically, the court vacated the SSM exemption 
contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that 
under CAA section 302(k), emissions standards or limitations must be 
continuous in nature and that the SSM exemption violates the CAA's 
requirement that some section 112 standards apply continuously. With 
the issuance of the mandate in Sierra Club v. EPA, the exemption 
language in 63.6(f)(1) and (h)(1) is null and void and any cross 
reference to those provisions has no effect.
    However, we disagree with other commenters suggesting that the EPA 
created loopholes for releases from PRDs at 40 CFR 63.165(e)(3)(v)(B) 
and (C) and smoking flares at 40 CFR 63.670(o)(7)(ii) and (iv) during 
malfunctions. At proposal, the EPA explained that ``[a]lthough no 
statutory language compels the EPA to set standards for malfunctions, 
the EPA has the discretion to do so where feasible.'' (88 FR 25167). We 
further explained that ``[t]he EPA will consider whether circumstances 
warrant setting work practice standards for a particular type of 
malfunction in the SOCMI, P&R I, and P&R II source categories, and, if 
so, whether the EPA has sufficient information to identify the relevant 
best performing sources and establish a standard for such 
malfunctions.'' (88 FR 25168.) It is very difficult to guard perfectly 
against acts of God and acts of terrorism. The EPA does not believe it 
can develop measures that would effectively limit emissions during all 
such acts.
    Regardless, the PRD work practice standard requires redundant 
prevention measures, which are designed to limit the duration and 
quantity of releases from all atmospheric PRDs regardless of the cause. 
Flares are required to comply with the requirements for a continuously 
lit pilot flame and combustion efficiency standards (i.e., limits on 
the NHVcz) at all times, including during periods of emergency flaring 
caused by a force majeure event. These requirements apply at all times; 
thus, the final work practice standards do have requirements that apply 
to PRDs and flares at all times and they are not contrary to the CAA 
requirements in CAA section 112. In addition, the work practice 
standard for PRDs requires installation and operation of continuous 
monitoring device(s) to identify when a PRD release has occurred. We 
also note that facilities are required to initiate a root cause 
analysis to assess the cause of a release, including releases 
determined to be caused by a force majeure event. The count of events 
at 40 CFR 63.165(e)(3)(v)(B) and (C) and smoking flares at 40 CFR 
63.670(o)(7)(ii) and (iv) includes events for which the root cause is 
determined to be force majeure. In other words, there is no 
categorization or interpretation related to the root cause of the 
event; and the corrective action component of the work practice 
standards applies to all events regardless of the root cause and all 
events would count towards the violation criteria set forth in the 
standard. We note that further comments on the concept of ``force 
majeure'' and our responses to these comments can be found in section 
7.2 of the document titled Summary of Public Comments and Responses for 
New Source Performance Standards for the Synthetic Organic Chemical 
Manufacturing Industry and National Emission Standards for Hazardous 
Air Pollutants for the Synthetic Organic Chemical Manufacturing 
Industry and Group I & II Polymers and Resins Industry, which is 
available in the docket for this rulemaking.
    We disagree with the comments regarding the exemptions being 
arbitrary and capricious. We modeled the applicability of the PRD 
provisions after the SCAQMD rule, based on a MACT floor analysis and 
considering the appropriate requirements for these types of PRDs. With 
regard to PRDs in EtO or chloroprene service, we stated in the preamble 
to the proposed rule (88 FR 25080, April 25, 2023) that any release 
event from a PRD in EtO (from the SOCMI source category) or chloroprene 
service (from the Neoprene Production source category) is a violation 
of the standard in order to help reduce risk from these source 
categories to an acceptable level.
    With regard to the request that we clarify the start date for the 
work practice standards, the regulatory text at 40 CFR 
63.165(e)(3)(iv), 40 CFR 63.165(e)(3)(v)(B) and (C) (for PRDs) and at 
40 CFR 63.670(o)(7(ii) and (iv) (for smoking flares), states that the 
time period is based on a 3-calendar-year period. We consider 2023 to 
be 1 calendar year. A 3-calendar-year period in 2023 would include 
events that occurred in 2021, 2022, and 2023. It is a rolling average 
to the extent that, in 2024, one would consider events that occurred in 
2022, 2023, and 2024. As indicated in 40 CFR 63.182(d)(2)(xviii)(C), 
each pressure release to the atmosphere, including the duration of the 
release, the estimated quantity of each organic HAP released, and the 
results of the root cause analysis and corrective action analysis 
completed during the reporting period must be included as part of the 
reporting obligation. We disagree with the comment regarding meeting 
certain criteria and not counting the second event from the same 
equipment and same root cause as a deviation. First, we want to clarify 
that we mean violation, not deviation. Our use of the term 
``deviation'' in the preamble to the proposed rule was an error 
(however, we did use ``violation'' in the proposed rule text in 40 CFR 
63.165). While the MON rule text uses the MON-defined term 
``deviation'' to describe emissions events, the current (and proposed) 
HON rule text uses the term ``violation.'' There are no uses of the 
term ``deviation'' to describe an emissions event in the current HON 
rule text, nor any definition in the HON of that term. Therefore, given 
that we are building off the existing HON standards, we believe it is 
more appropriate to continue to use the term ``violation'' (in lieu of 
the undefined ``deviation'') in all of the HON rule text. Second, at 
proposal, we

[[Page 43026]]

explained that two release events with the same root cause from a 
single PRD in a 3-year period is a violation from the MACT standard. 88 
FR 25157. The commenter requested that if a corrective action has not 
been implemented to resolve an issue, then related PRD releases should 
not be counted towards the violation; however, this result is exactly 
what the EPA wants to prevent by having a lower release threshold for 
violations when a PRD release results from the same root cause.
4. What is the rationale for our final approach and final decisions to 
address emissions during periods of SSM?
    We evaluated all of the comments on the EPA's proposed amendments 
to the SSM provisions. For the reasons explained in the proposed rule 
(88 FR 25080, April 25, 2023), we determined that these amendments, 
which remove and revise provisions related to SSM, are necessary to be 
consistent with the requirement that the standards apply at all times. 
More information concerning the amendments we are finalizing for SSM is 
in the preamble to the proposed rule (88 FR 25080, April 25, 2023) and 
in the comments and our specific responses to the comments in the 
document titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking. Therefore, we are finalizing our approach for the SSM 
provisions as proposed.

E. Amendments Addressing NSPS Subparts VV and VVa Reconsideration

1. What amendments did we propose to address the NSPS subparts VV and 
VVa reconsideration?
    In response to the January 2008 petition for reconsideration, we 
proposed: (1) Definitions for ``process unit'' for NSPS subparts VV and 
VVa that are the same or essentially the same \60\ as the definition of 
``process unit'' that was first promulgated in NSPS subpart VV (see 48 
FR 48307, October 18, 1983) and that applied during the stay of the 
2007 amendments to this definition in both NSPS subparts VV and VVa; 
(2) to remove the requirements in 40 CFR 60.482-1(g) (for NSPS subpart 
VV) and 40 CFR 60.482-1a(g) (for NSPS subpart VVa) that are related to 
a method for assigning shared storage vessels to specific process 
units; (3) to remove the connector monitoring provisions from NSPS 
subpart VVa at 40 CFR 60.482-11a in their entirety; and (4) to revise 
the ``capital expenditure'' definition in NSPS subpart VVa at 40 CFR 
60.481a such that for owners or operators that start a new, 
reconstructed, or modified affected source prior to November 16, 
2007,\61\ the variable Y (i.e., the percent of a facility's replacement 
cost used in determining an adjusted annual asset guideline repair 
allowance) is determined from the following equation: Y = 1.0 - 0.575 
log X, where the value of ``X'' is 1982; \62\ for owners or operators 
that start a new, reconstructed, or modified affected source on or 
after November 16, 2007,\63\ for which the NSPS subpart VVa definition 
of ``capital expenditure'' was not stayed, we proposed to continue to 
apply the definition in NSPS subpart VVa (i.e., the value of ``X'' is 
2006 minus the year of construction).\64\
---------------------------------------------------------------------------

    \60\ The proposed ``process unit'' definition in NSPS subpart VV 
is the same as that initially promogulated in NSPS subpart VV in 
1983 (i.e., ``components assembled to produce, as intermediate or 
final products, one or more of the chemicals listed in Sec.  60.489 
of this part''). The proposed ``process unit'' definition in NSPS 
subpart VVa is the same except that it refers to the chemicals 
listed in Sec.  60.489a instead of Sec.  60.489.
    \61\ As explained later in section IV.E.3 of this preamble, the 
proposed definition erroneously refers to ``owners or operators that 
start a new, reconstructed, or modified affected source prior to 
November 16, 2007'' instead of sources that underwent physical or 
operational change prior to November 16, 2007 (but after November 7, 
2006, the NSPS subpart VVa proposal date).
    \62\ ``1982'' is the X value presented in our proposed 
regulatory text. We note that in the preamble to the proposal, we 
had expressed an intent to define ``X'' as ``1982 minus the year of 
construction,'' which reflects the equation for Y in the definition 
in NSPS subpart VV at 40 CFR 60.481 and which applied during the 
stay of the ``capital expenditure'' definition in NSPS subpart VVa. 
See 40 CFR 60.480a(f)(1) (``Stay of standards'').
    \63\ As explained later in section IV.E.3 of this preamble, the 
proposed definition erroneously refers to ``owners or operators that 
start a new, reconstructed, or modified affected source on or after 
November 16, 2007'' instead of sources that underwent physical or 
operational change on or after November 16, 2007.
    \64\ See the document titled Proposed Regulation Edits for 40 
CFR part 60 Subparts VV, VVa, and VVb: Standards of Performance for 
Equipment Leaks of VOC in the Synthetic Organic Chemicals 
Manufacturing Industry (see Docket Item No. EPA-HQ-OAR-2022-0730-
0067).
---------------------------------------------------------------------------

2. How did the revisions addressing the NSPS subparts VV and VVa 
reconsideration change since proposal?
    We are finalizing the changes described in section IV.E.1 of this 
preamble as proposed, except for certain changes related to the 
``capital expenditure'' definition in NSPS subpart VVa. For NSPS 
subpart VVa, we are finalizing the ``capital expenditure'' definition 
in NSPS subpart VVa in place during the stay of the definition for 
facilities that underwent a physical or operational change prior to 
November 16, 2007. We recognize, depending on the year a modification 
took place, this definition may potentially leave an indeterminant 
outcome (e.g., log (X) where X is a negative value) for calculation of 
the adjusted annual asset guideline repair allowance. However, to the 
extent there were sources that encountered this scenario (where a 
physical or operational change between November 7, 2006 and November 
16, 2007 triggered an evaluation of whether the capital expenditure was 
above the threshold to be considered a modification), the NSPS subpart 
VVa applicability determination would have been resolved a long time 
ago; thus, finalizing the same definition as applied during the stay 
would avoid upending any long-standing determinations. Therefore, in 
the final rule, we are finalizing the definition that was in place 
during the stay, which include correcting several errors made in our 
proposed definition and noted by commenters. Specifically, the proposed 
definition erroneously attached the value of ``X'' in the percent Y 
equation to the date of construction, reconstruction, and modification 
(as opposed to date of physical or operational change); in the final 
rule, we have replaced that phrasing with a reference to physical and 
operation change. In addition, we revised the value of ``X'' from 
``1982'' to ``1982 minus the year of construction.'' Accordingly, in 
the final rule, we are revising the ``capital expenditure'' definition 
in NSPS subpart VVa at 40 CFR 60.481a such that for owners or operators 
that made a physical or operational change to their existing facility 
prior to November 16, 2007, the percent Y is determined from the 
following equation: Y = 1.0 - 0.575 log X, where the value of ``X'' is 
1982 minus the year of construction; for owners or operators that made 
a physical or operational change to their existing facility on or after 
November 16, 2007, the percent Y is determined from the following 
equation: Y = 1.0 - 0.575 log X, where the value of ``X'' is 2006 minus 
the year of construction.
3. What key comments did we receive on the revisions addressing the 
NSPS subparts VV and VVa reconsideration and what are our responses?
    This section provides summaries of and responses to the key 
comments received regarding our proposed requirements for connectors 
and

[[Page 43027]]

proposed revisions to the requirements in NSPS subpart VVa for capital 
expenditure. Except for these comments related to the proposed 
requirements for connectors and capital expenditure, we did not receive 
many substantive comments on the other amendments related the NSPS 
subparts VV and VVa reconsideration. The comments we received regarding 
other amendments generally include issues related to the definition of 
``process unit.'' The comments and our specific responses to these 
issues can be found in the document titled Summary of Public Comments 
and Responses for New Source Performance Standards for the Synthetic 
Organic Chemical Manufacturing Industry and National Emission Standards 
for Hazardous Air Pollutants for the Synthetic Organic Chemical 
Manufacturing Industry and Group I & II Polymers and Resins Industry, 
which is available in the docket for this rulemaking.
    Comment: A commenter objected to the EPA removing the connector 
monitoring provisions from NSPS subpart VVa and only proposing them in 
NSPS subpart VVb. The commenter contended that the EPA did not provide 
sufficient justification for this change, given that the EPA's 
rationale was only that they agreed with Petitioners that it had not 
included those requirements in the November 7, 2006, proposal (72 FR 
64860) but then established connector monitoring requirements in the 
November 16, 2007 final rule without notice and an opportunity to 
comment. The commenter added that the EPA must also justify why it is 
not appropriate to lift the stay and require connector monitoring at 
sources subject to NSPS subpart VVa from this point forward. The 
commenter listed several issues with the EPA's decision:
     The EPA must propose and provide opportunity for comment 
on requiring connector monitoring at sources subject to NSPS subpart 
VVa. The basis of the reconsideration was a lack of notice and comment, 
and the EPA is currently in the position to provide an opportunity for 
comment on those requirements yet fails to do so with no explanation.
     The EPA must justify why additional emissions reductions 
for sources subject to NSPS subpart VVa are no longer appropriate 
before simply removing the requirements in their entirety. The EPA 
found connector monitoring as the ``best system of emission reduction'' 
in the November 16, 2007, preamble, and the EPA has not explained why 
that determination was inappropriate or no longer valid. In EPA's 
analysis supporting the final NSPS subpart VVa, it found that the 
promulgated connector monitoring requirements were: (1) Common practice 
at many chemical manufacturing facilities, including through 
regulations such as HON, MON, Ethylene MACT, and the Generic MACT (40 
CFR 63, subpart UU), (2) resulted in greater emission reductions (230 
tpy VOC) than the changes the EPA implemented for pumps and valves (94 
tpy VOC) in NSPS subpart VVa, and (3) were achieved at a cost $2,500 
per ton of VOC reduced.
     The EPA must justify why the same requirements it is 
proposing to remove from NSPS subpart VVa are only appropriate for NSPS 
subpart VVb.
    The commenter asserted that the EPA can and must lift the stay as 
it relates to connector monitoring in 40 CFR 60.482-11a and require 
compliance with that section from that date forward in order to ensure 
the critical (and cost-effective) environmental protections are 
implemented, while avoiding concerns of retroactive application of 
standards. The EPA could do this through providing language that the 
standards were stayed from June 2, 2008, until the date of the final 
rule, but are in effect moving forward.
    Response: As previously discussed in the preamble to the proposed 
rule (88 FR 25080, April 25, 2023), we proposed to remove the connector 
monitoring requirements in NSPS subpart VVa that have been stayed since 
2008. The EPA disagrees with the comment that, having granted 
reconsideration of these requirements because they were finalized 
without proposal and an opportunity for comment, the EPA must now 
propose to remove the stay and provide the public an opportunity to 
comment on the connector requirements. While CAA section 307(d)(7)(B) 
requires that the EPA grant reconsideration in this situation (where 
the grounds for objecting to the standard arose after the period for 
public comment, in this case when the final rule was promulgated), 
nothing in CAA section 307(d)(7)(B) or elsewhere in the CAA dictates 
what actions the EPA must take in a reconsideration proceeding, much 
less requiring that the EPA propose the connector requirements for 
comment; nor has the commenter cited any legal authority requiring such 
action from the EPA in an administrative reconsideration proceeding 
under CAA section 307(d)(7)(B).
    In its reconsideration of the connector requirements in NSPS 
subpart VVa, the EPA took into account that these requirements have 
been stayed since June 2008, over 15 years ago and shortly after the 
promulgation of NSPS subpart VVa in November 2007. In light of the fact 
that the connector requirements have not been part of NSPS subpart 
VVa's long implementation history, the EPA does not think it is 
appropriate to amend NSPS subpart VVa now to add a new requirement for 
new equipment (i.e., connectors) for sources constructed, reconstructed 
or modified between November 7, 2006 and April 26, 2023, which are 
existing sources for purposes of the newly promulgated NSPS subpart 
VVb. The EPA believes that standards for previously unregulated sources 
such as the connectors are better suited moving forward for new and 
modified sources under NSPS subpart VVb. For the reasons stated above, 
the EPA is finalizing the removal of the connector requirements in NSPS 
subpart VVa, as proposed.
    Comment: Commenters requested the EPA correct the formula for 
calculating the value of ``X'' in the definition of ``Capital 
Expenditure'' in the proposed NSPS subpart VVa. A commenter explained 
that the EPA proposed a value of ``1982'' for ``X'' for owners or 
operators ``that start a new, reconstructed, or modified affected 
source prior to November 16, 2007.'' The commenter contended that this 
results in a negative value for ``Y'' (that is, -0.89, or 1.0-
0.575log(1982)), being effectively an indeterminant outcome for 
calculation of the adjusted annual asset guideline repair allowance. 
Another commenter recommended that the EPA revise ``X'' from ``1982'' 
to ``1982--the year of construction'' for owners or operators ``that 
start a new, reconstructed, or modified affected source prior to 
November 16, 2007.''
    Another commenter contended that the EPA's proposed definition for 
capital expenditures in NSPS subpart VVa narrows the reach of 
modification and would result in the exclusion of certain process units 
from applicability to the subpart through modification. For NSPS 
subpart VVa, the commenter contended the EPA has made significant 
errors in defining how sources would determine if modification has 
occurred and went beyond addressing the issues raised by the 
petitioners requesting reconsideration of the capital expenditure 
definition. The commenter asserted that it is inappropriate to include 
a definition for modification related to a date of construction, 
reconstruction, or modification that operates apart from the 
applicability of the individual subpart. The commenter explained that a 
source that is constructed or reconstructed after the applicability 
date of the subpart (November 7, 2006, for NSPS subpart

[[Page 43028]]

VVa) is automatically subject to the standards of that subpart and 
modification has no relevance unless a subpart with a later 
applicability date is promulgated. The commenter added that a source is 
not defined as modified unless it undergoes a physical or operational 
change that results in an increase in emissions. The commenter 
contended that a definition of capital expenditure that is reliant on 
the dates of ``construction, reconstruction, or modification'' is not 
relevant to and has no bearing on whether a source has been modified. 
The commenter concluded that the EPA must redefine capital expenditure 
without specifying construction, reconstruction, or modification dates. 
The commenter recommended that the EPA should seek to address the 
definition of capital expenditure as it applies to the subset of 
physical and operational changes that occurred specifically between 
November 7, 2006, and November 16, 2007. The commenter added that for 
those sources that would have utilized the capital expenditure equation 
in NSPS subpart VV, it is appropriate to define the value of ``X'' as 
``1982 minus the year of construction'' or simply cross-reference the 
capital expenditure definition at 40 CFR 60.481. The commenter stated 
that the definition of capital expenditure as it relates to physical 
and operational changes that take place after November 16, 2007 (the 
promulgation date of NSPS subpart VVa), was not under reconsideration 
and should remain as promulgated such that the EPA define ``X'' based 
on the dates of ``physical or operational changes'' regardless of the 
date of construction, reconstruction, or modification, and 
specifically, for physical or operational changes that take place after 
November 16, 2007, ``X'' should remain defined as ``2006 minus the year 
of construction.''
    Response: We agree that errors were made in the proposed ``capital 
expenditure'' definition in NSPS subpart VVa. The proposed definition, 
in relevant part, stated that
    ``(2) The percent Y is determined from the following equation: Y = 
1.0 - 0.575 log X, where X is:
    (i) 2006 minus the year of construction for owners or operators 
that start a new, reconstructed, or modified affected source on or 
after November 16, 2007, or
    (ii) 1982 for owners or operators that start a new, reconstructed, 
or modified affected source prior to November 16, 2007;''
    We agree with the comment that the proposed definition erroneously 
relies on a sources' construction, reconstruction, or modification date 
for calculating capital expenditure to determine whether modification 
has been triggered for that source. Sources constructed, modified, or 
reconstructed after November 7, 2006, are affected facilities under 
NSPS subpart VVa (i.e., they are subject to the standards of NSPS 
subpart VVa); whether any such NSPS subpart VVa affected facility has 
subsequently incurred capital expenditure that would constitute 
``modification'' is irrelevant as the only purpose for that capital 
expenditure calculation is to determine NSPS subpart VVa applicability, 
which we already know it does. The commenter also correctly notes that 
modification is determined by whether there is a physical or 
operational change that results in an increase in emissions. See 40 CFR 
60.2 and CAA section 111(a)(4). For the reasons stated above, in the 
final rule, we have revised the proposed ``capital expenditure'' 
definition by referencing the date of a physical or operational change 
to a source instead its construction, modification and reconstruction 
date.
    Regarding the value of ``X'' for owners and operators that made a 
physical or operation change to their existing facility prior to 
November 16, 2007, commenters are correct that the value of ``X'' being 
1982 results in a negative value for the variable ``Y''; the proposed 
regulation edits (see Docket Item No. EPA-HQ-OAR-2022-0730-0067) 
mistakenly required the value of ``X'' be 1982 instead of the intended 
equation. The intended equation for ``X'' was 1982 minus the year of 
construction; this equation was described in the proposal preamble (88 
FR 25172) and aligns with the commenters' recommendation, which we 
acknowledge could still result in a nonsensical value for the variable 
``Y'' for certain scenarios. However, the impact of this issue is 
unclear, as it would affect only sources that made a physical or 
operational change within the relevant one-year period (after November 
7, 2006 but before November 16, 2007). To the extent there were such 
sources, we believe that they had long ago found ways to resolve the 
issue and determine NSPS subpart VVa applicability, perhaps in 
consultation with the relevant EPA region or delegated State agencies; 
thus, finalizing the same definition as that which was in effect during 
the relevant one-year period would avoid upending any such long-
standing resolutions or determinations by owners/operators and/or EPA 
or delegated State agencies.
    For the reasons described above, we are finalizing the equation for 
calculating the variable ``Y'' in the definition of ``capital 
expenditure'' in NSPS subpart VVa as follows:
    (2) The percent Y is determined from the following equation: Y = 
1.0 - 0.575 log X, where X is:
    (i) 2006 minus the year of construction if the physical or 
operational change to the existing facility was on or after November 
16, 2007, or
    (ii) 1982 minus the year of construction if the physical or 
operational change to the existing facility was prior to November 16, 
2007.
4. What is the rationale for our final approach and final decisions to 
address the NSPS subparts VV and VVa reconsideration?
    The amendments address the following issues raised in the January 
2008 petition for reconsideration: (1) The clarification of the 
definition of process unit in NSPS subparts VV and VVa; (2) the 
assignment of shared storage vessels to specific process units in NSPS 
subparts VV and VVa; (3) the monitoring of connectors in NSPS subpart 
VVa; and (4) the definition of capital expenditure in NSPS subpart VVa. 
More information concerning the amendments we are finalizing to address 
these issues is in the preamble to the proposed rule and in the 
comments and our specific responses to the comments in the document 
titled Summary of Public Comments and Responses for New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this rulemaking.

F. Other Amendments to the NESHAP and NSPS

1. What other amendments did we propose for the SOCMI, P&R I, and P&R 
II source categories?
    We proposed a requirement that owners or operators submit 
electronic copies of certain required performance test reports, flare 
management plans, and periodic reports (including fenceline monitoring 
reports for HON and the P&R I NESHAP) through the EPA's CDX using the 
CEDRI (at 40 CFR 63.108(e), 40 CFR 63.152(c) and (h), and 40 CFR 
63.182(d) and (e) (for HON), 40 CFR 63.506(e)(6), and (i)(3) (for the 
P&R I NESHAP), and 40 CFR 63.528(a) and (d) (for the P&R II NESHAP), 40 
CFR 60.486(l), and 60.487(a) and (g) through (i) (for NSPS subpart VV), 
40 CFR

[[Page 43029]]

60.486a(l), and 60.487a(a) and (g) through (i) (for NSPS subpart VVa), 
40 CFR 60.486b(l), and 60.487b(a) and (g) through (i) (for NSPS subpart 
VVb), 40 CFR 60.615(b), (j), (k), and (m) through (o) (for NSPS subpart 
III), 40 CFR 60.615a(b), (h) through (l), and (n), and 40 CFR 619a(e) 
(for NSPS subpart IIIa), 40 CFR 60.665(b), (l), (m), and (q) through 
(s) (for NSPS subpart NNN), 40 CFR 60.665a(b), (h), (k) through (n), 
and (p), and 40 CFR 669a(e) (for NSPS subpart NNNa), 40 CFR 60.705(b), 
(l), (m), and (u) through (w) (for NSPS subpart RRR), and 40 CFR 
60.705a(b), (k) through (o), and (v), and 40 CFR 709a(e) (for NSPS 
subpart RRRa)). We also proposed two narrow circumstances in which 
owners or operators may seek extensions to the deadline if they are 
prevented from reporting by conditions outside of their control within 
five business days of the reporting deadline. We proposed that an 
extension may be warranted due to outages of the EPA's CDX or CEDRI 
that precludes an owner or operator from accessing the system and 
submitting required reports. We also proposed that an extension may be 
warranted due to a force majeure event, such as an act of nature, act 
of war or terrorism, or equipment failure or safety hazards beyond the 
control of the facility.
    In addition, we proposed the restructuring of all HON definitions 
from NESHAP subparts G and H (i.e., 40 CFR 63.111 and 40 CFR 63.161, 
respectively) into the definition section of NESHAP subpart F (i.e., 40 
CFR 63.101); and we proposed to consolidate differences between certain 
definitions in these subparts.
    We proposed adding monitoring requirements at 40 CFR 
63.114(a)(5)(v), 40 CFR 63.120(d)(1)(iii), 40 CFR 63.127(b)(4), and 40 
CFR 63.139(d)(5) (for HON), and 40 CFR 63.484(t), 40 CFR 63.485(x), and 
40 CFR 63.489(b)(10) (for the P&R I NESHAP) for owners or operators 
using adsorbers that cannot be regenerated and regenerative adsorbers 
that are regenerated offsite. We also proposed that owners or operators 
of this type of APCD use dual (two or more) adsorbent beds in series 
and conduct monitoring of HAP or TOC on the outlet of the first 
adsorber bed in series using a sample port and a portable analyzer or 
chromatographic analysis.
    In addition, we proposed several corrections to the calibration 
drift assessment requirements in NSPS subpart VVa at 40 CFR 
60.485a(b)(2) including: (1) Correcting a regulatory citation to read 
``Sec.  60.486a(e)(8)'' instead of ``Sec.  60.486a(e)(7)''; (2) 
removing the extraneous sentence ``Calculate the average algebraic 
difference between the three meter readings and the most recent 
readings and the most recent calibration value.''; (3) providing 
clarity in the mathematical step of the assessment by replacing the 
sentence ``Divide this algebraic difference by the initial calibration 
value and multiply by 100 to express the calibration drift as a 
percentage.'' with ``Divide the arithmetic difference of the initial 
and post-test calibration response by the corresponding calibration gas 
value for each scale and multiply by 100 to express the calibration 
drift as a percentage.''; and (4) providing clarity by making other 
minor textural changes to the provisions related to the procedures for 
when a calibration drift assessment shows negative or positive drift of 
more than 10 percent.
    We also proposed at 40 CFR 63.103(b)(1) (for HON), 40 CFR 63.490(g) 
and 40 CFR 63.504(a) (for the P&R I NESHAP), and 40 CFR 64.525(a), (e), 
and (m) (for the P&R II NESHAP) that owners and operators would be 
required to conduct subsequent performance testing on non-flare control 
devices no later than 60 calendar months after the previous performance 
test.
    We also proposed to: (1) Remove the provisions at 40 CFR 63.110(h) 
that allow compliance with certain portions of 40 CFR part 264, subpart 
AA or CC in lieu of portions of NESHAP subpart G; and (2) remove the 
provisions at 40 CFR 63.110(i) and 40 CFR 60.160(g) that allow 
compliance with certain portions of 40 CFR part 65 in lieu of portions 
of NESHAP subparts G and H.
    Finally, we proposed revisions to clarify text or correct 
typographical errors, grammatical errors, and cross-reference errors. 
These editorial corrections and clarifications are discussed in section 
III.E.5.f of the proposal preamble (see 88 FR 25080, April 25, 2023).
2. How did the other amendments for the SOCMI, P&R I, and P&R II source 
categories change since proposal?
    Based on comments received on the proposed rulemaking, we are 
making some changes to the amendments described in section IV.F.1 of 
this preamble.
    With regard to electronic reporting, we are making several minor 
clarifying edits to the spreadsheet reporting templates (the final 
versions of the templates will be located on the CEDRI website). We are 
also making only minor changes to the HON definitions.
    In addition, for adsorbers that cannot be regenerated and 
regenerative adsorbers that are regenerated offsite, we have clarified 
the proposed rule text in this final action that the monitoring plan 
provisions in 40 CFR 63.120(d)(2) and (3) do not apply to HON sources 
subject to the monitoring provisions in 40 CFR 63.120(d)(1)(iii); and 
the monitoring plan provisions in 40 CFR 63.120(d)(2) and (3) do not 
apply to P&R I sources subject to the monitoring provisions in 40 CFR 
63.120(d)(1)(iii) (via 40 CFR 63.484(t) and 40 CFR 63.485(x)).
    With regard to overlap provisions, we are: (1) Revising 40 CFR 
63.160(b)(1) and (c)(1) in the final rule such that compliance with HON 
subpart H constitutes compliance with NSPS subpart VVa provided the 
owner or operator continues to comply with 40 CFR 60.480a(e)(2)(i); and 
(2) revising 40 CFR 63.160(b)(1) and (c)(1) in the final rule such that 
compliance with HON subpart H constitutes compliance with NSPS subpart 
VVb provided the owner or operator continues to comply with 40 CFR 
60.480b(e)(2)(i). We have also revised 40 CFR 60.480b(e)(2)(i) in the 
final rule to require compliance with 40 CFR 60.482-7b (i.e., the 
standards for gas and light liquid valves in NSPS subpart VVb) in 
addition to the requirements of 40 CFR 60.485b(d), (e), and (f), and 40 
CFR 60.486b(i) and (j).
3. What key comments did we receive on the other amendments for the 
SOCMI, P&R I, and P&R II source categories and what are our responses?
    We did not receive many substantive comments on the other 
amendments discussed in this section IV.F of this preamble. The 
comments we received regarding other amendments generally include 
issues related to electronic reporting, the restructuring of all HON 
definitions, adsorbers that cannot be regenerated and regenerative 
adsorbers that are regenerated offsite, overlap provisions, and 
revisions that we proposed for clarifying text or correcting 
typographical errors, grammatical errors, and cross-reference errors. 
The comments and our specific responses to these issues can be found in 
the document titled Summary of Public Comments and Responses for New 
Source Performance Standards for the Synthetic Organic Chemical 
Manufacturing Industry and National Emission Standards for Hazardous 
Air Pollutants for the Synthetic Organic Chemical Manufacturing 
Industry and Group I & II Polymers and Resins Industry, which is 
available in the docket for this rulemaking.

[[Page 43030]]

4. What is the rationale for our final approach and final decisions 
regarding the other amendments for the SOCMI, P&R I, and P&R II source 
categories?
    Based on the comments received for these other amendments, we are 
generally finalizing all proposed requirements. In a few instances, we 
received comments that led to additional minor editorial corrections 
and technical clarifications being made in the final rule, and our 
rationale for these corrections and technical clarifications can be 
found in section IV.F.3 of this preamble and in the document titled 
Summary of Public Comments and Responses for New Source Performance 
Standards for the Synthetic Organic Chemical Manufacturing Industry and 
National Emission Standards for Hazardous Air Pollutants for the 
Synthetic Organic Chemical Manufacturing Industry and Group I & II 
Polymers and Resins Industry, which is available in the docket for this 
rulemaking.

V. Summary of Cost, Environmental, and Economic Impacts and Additional 
Analyses Conducted

A. What are the affected sources?

    There are approximately 207 facilities subject to the HON, 19 P&R I 
facilities (and 10 of these P&R I facilities are collocated with HON 
processes), and 5 P&R II facilities (and 3 of these P&R II facilities 
are collocated with HON processes). We also estimate that two 
additional HON facilities will be newly constructed over the next 3 
years. The Office of Enforcement and Compliance Assurance's ECHO 
(Enforcement and Compliance History Online) tool (https://echo.epa.gov) 
indicates there are currently 592 SOCMI facilities subject to subpart 
VV or VVa; and 284 SOCMI facilities subject to at least one of the 
process vent NSPS subparts III, NNN, and/or RRR. The list of facilities 
is available in the document titled Lists of Facilities Subject to the 
HON, Group I and Group II Polymers and Resins NESHAPs, and NSPS 
subparts VV, VVa, III, NNN, and RRR (see Docket Item No. EPA-HQ-OAR-
2022-0730-0069). We estimate that there will be one new greenfield 
facility, six new affected facilities constructed at existing plant 
sites, and 12 modified/reconstructed facilities subject to NSPS subpart 
IIIa, NNNa, and/or RRRa in the next 5 years. We estimate there will be 
one new greenfield facility, 34 new affected facilities constructed at 
existing plant sites, and one modified facility subject to NSPS subpart 
VVb in the next 5 years (and no affected facilities will trigger NSPS 
subpart VVa reconstruction requirements).

B. What are the air quality impacts?

    This final action will reduce HAP emissions by at least 1,372 tpy 
and VOC emissions by 3,820 tpy from HON, P&R I, and P&R II emission 
sources as well as the NSPS SOCMI air oxidation unit processes, 
distillation operations, reactor processes, and equipment leaks 
sources. These emission reductions are broken down by rule as follows. 
Considering reported emissions inventories for EtO and chloroprene, we 
estimate that the final amendments to the NESHAP will reduce overall 
HAP emissions from the SOCMI source category by approximately 1,107 tpy 
(and 1,919 tpy of VOC), reduce overall HAP emissions from the P&R I 
source categories by approximately 264 tpy (and 278 tpy of VOC), and 
reduce overall HAP and VOC emissions from the P&R II source categories 
by approximately 1 tpy. We note that these emissions reductions do not 
consider the potential excess emissions reductions from flares that 
could result from the final monitoring requirements; we estimate flare 
excess emissions reductions of 4,858 tpy HAP and 19,889 tpy VOC. Based 
on our analysis of the finalized actions described in sections III.B.2, 
III.D.2, and III.E of this preamble for the NSPS, we estimate that the 
final amendments to the NSPS would reduce VOC emissions from the SOCMI 
source category by approximately 1,622 tpy. The Agency was unable to 
estimate HAP emission reductions for the final amendments to the NSPS 
in this rulemaking. Emission reductions and secondary impacts (e.g., 
emission increases associated with supplemental fuel or additional 
electricity) by rule are listed below. The only change in air impacts 
since proposal stems from our reevaluation related to the TRE removal 
for HON and the P&R I NESHAP, and its discontinued use in the new NSPS 
subparts IIIa, NNNa, and RRRa (based on comments received as discussed 
in sections IV.B.3.a.i and IV.B.3.b.i of this preamble).
1. HON
    For the HON, the EPA estimates HAP and VOC emission reductions of 
approximately 1,107 and 1,919 tpy, respectively. The EPA estimates 
these reductions include an approximate 54 tpy reduction in EtO 
emissions (from reported emissions inventories) and a reduction of 
20,177 tpy of methane emissions. The EPA also estimates that the final 
action would result in additional emissions of 714 tpy of CO; 609,761 
tpy of CO2; 277 tpy of NOX (including 5.3 tpy of 
N2O); 12.7 tpy of particulate matter; and 1.0 tpy of 
SO2. More information about the estimated emission 
reductions and secondary impacts of this final action for the HON can 
be found in the RIA accompanying this rulemaking, the documents 
referenced in sections III.B through III.D of the preamble to the 
proposed rule (88 FR 25080, April 25, 2023), and in the document titled 
Clean Air Act Section 112(d)(6) Technology Review for Continuous 
Process Vents Located in the SOCMI Source Category that are Associated 
with Processes Subject to HON, Continuous Front-end and Batch Front-end 
Process Vents Associated with Processes Subject to Group I Polymers and 
Resins NESHAP, and Process Vents Associated with Processes Subject to 
Group II Polymers and Resins NESHAP--FINAL, which is available in the 
docket for this rulemaking.
2. P&R I NESHAP
    For the P&R I NESHAP, the EPA estimates HAP and VOC emission 
reductions of approximately 264 and 278 tpy, respectively. The EPA 
estimates these reductions include an approximate 14 tpy reduction in 
chloroprene emissions (from reported emissions inventories); and a 
reduction of 2,018 tpy of methane emissions. The EPA also estimates 
that the final action would result in additional emissions of 110 tpy 
of CO; 115,975 tpy of CO2; 75 tpy of NOX 
(including 1.5 tpy of N2O); 4.8 tpy of particulate matter; 
and 0.4 tpy of SO2. More information about the estimated 
emission reductions and secondary impacts of this final action for the 
P&R I NESHAP can be found in the RIA accompanying this rulemaking, the 
documents referenced in sections III.B through III.D of the preamble to 
the proposed rule (88 FR 25080, April 25, 2023), and in the document 
titled Clean Air Act Section 112(d)(6) Technology Review for Continuous 
Process Vents Located in the SOCMI Source Category that are Associated 
with Processes Subject to HON, Continuous Front-end and Batch Front-end 
Process Vents Associated with Processes Subject to Group I Polymers and 
Resins NESHAP, and Process Vents Associated with Processes Subject to 
Group II Polymers and Resins NESHAP--FINAL, which is available in the 
docket for this rulemaking.
3. P&R II NESHAP
    For the P&R II NESHAP, the EPA estimates 1 tpy of HAP and VOC 
emission reductions. The EPA also estimates that the final action would 
not have any secondary pollutant impacts. More information about the 
estimated

[[Page 43031]]

emission reductions and secondary impacts of this final action for the 
P&R II NESHAP can be found in the RIA accompanying this rulemaking and 
the documents referenced in sections III.B through III.D of the 
preamble to the proposed rule (88 FR 25080, April 25, 2023).
4. NSPS Subpart VVb
    For the final NSPS subpart VVb, the EPA estimates VOC emission 
reductions of approximately 340 tpy. The EPA estimates that the final 
action would not have any secondary pollutant impacts. More information 
about the estimated emission reductions and secondary impacts of this 
final action for NSPS subpart VVb can be found in the RIA accompanying 
this rulemaking and, in the document titled CAA 111(b)(1)(B) review for 
the SOCMI Equipment Leaks NSPS Subpart VVa (see Docket Item No. EPA-HQ-
OAR-2022-0730-0096).
5. NSPS Subparts IIIa, NNNa, and RRRa
    For the final NSPS subparts IIIa, NNNa, and RRRa, the EPA estimates 
VOC emission reductions of approximately 1,281 tpy and a reduction of 
757 tpy of methane emissions. The EPA estimates that the final action 
result in additional emissions of 21.5 tpy of CO; 15,370 tpy of 
CO2; and 4.0 tpy of NOX (including 0.1 tpy of 
N2O). More information about the estimated emission 
reductions and secondary impacts of this final action for NSPS subparts 
IIIa, NNNa, and RRRa can be found in the RIA accompanying this 
rulemaking and in the document titled CAA 111(b)(1)(B) review for the 
SOCMI air oxidation unit processes, distillation operations, and 
reactor processes NSPS subparts III, NNN, and RRR--FINAL, which is 
available in the docket for this rulemaking.

C. What are the cost impacts?

    This final action will cumulatively cost (in 2021 dollars) 
approximately $522 million in total capital costs and $194 million per 
year in total annualized costs (including product recovery),\65\ based 
on our analysis of the final action described in sections III and IV of 
this preamble (see table 6 in section V.C.1 of this preamble).\66\ 
Costs by rule are listed below. The only change in cost impacts since 
proposal stems from our reevaluation related to the TRE removal for HON 
and the P&R I NESHAP, and its discontinued use in the new NSPS subparts 
IIIa, NNNa, and RRRa (based on comments received as discussed in 
sections IV.B.3.a.i and IV.B.3.b.i of this preamble).
---------------------------------------------------------------------------

    \65\ Recovered chemical product affected by this rulemaking is 
related to LDAR control options for equipment leaks and heat 
exchange systems, and is monetized as recovery credits by 
multiplying VOC emissions reductions by a VOC credit of $900 per ton 
(2021 dollars). This recovery credit has historically been used by 
the EPA to represent the variety of chemicals that are used as 
reactants and produced at SOCMI facilities.
    \66\ The annualized costs for each final rule include the costs 
of compliance, including those for monitoring, recordkeeping, and 
reporting. Recordkeeping and reporting costs for each final rule are 
presented separately in section VI.B of this preamble.
---------------------------------------------------------------------------

1. HON
    For the HON, the EPA estimates this final action will cost 
approximately $455 million in total capital costs and $169 million per 
year in total annualized costs (including product recovery). More 
information about the estimated cost of this final action for the HON 
can be found in the documents referenced in sections III.B through 
III.D of the preamble to the proposed rule (88 FR 25080, April 25, 
2023), and in the document titled Clean Air Act Section 112(d)(6) 
Technology Review for Continuous Process Vents Located in the SOCMI 
Source Category that are Associated with Processes Subject to HON, 
Continuous Front-end and Batch Front-end Process Vents Associated with 
Processes Subject to Group I Polymers and Resins NESHAP, and Process 
Vents Associated with Processes Subject to Group II Polymers and Resins 
NESHAP--FINAL, which is available in the docket for this rulemaking. 
The HON represents the majority of total estimated costs for this 
action (see Table 6 of this preamble).
[GRAPHIC] [TIFF OMITTED] TR16MY24.009

2. P&R I NESHAP
    For the P&R I NESHAP, the EPA estimates this final action will cost 
approximately $28 million in total capital costs and $15 million per 
year in total annualized costs (including product recovery). More 
information about the estimated cost of this final action for the P&R I 
NESHAP can be found in the documents referenced in sections III.B 
through III.D of the preamble to the proposed rule (88 FR 25080, April 
25, 2023), and in the document titled Clean Air Act Section

[[Page 43032]]

112(d)(6) Technology Review for Continuous Process Vents Located in the 
SOCMI Source Category that are Associated with Processes Subject to 
HON, Continuous Front-end and Batch Front-end Process Vents Associated 
with Processes Subject to Group I Polymers and Resins NESHAP, and 
Process Vents Associated with Processes Subject to Group II Polymers 
and Resins NESHAP--FINAL, which is available in the docket for this 
rulemaking.
3. P&R II NESHAP
    For the P&R II NESHAP, the EPA estimates this final action will 
cost approximately $2.9 million in total capital costs and $1.7 million 
per year in total annualized costs (including product recovery). More 
information about the estimated cost of this final action for the P&R 
II NESHAP can be found in the documents referenced in sections III.B 
through III.D of the preamble to the proposed rule (88 FR 25080, April 
25, 2023).
4. NSPS Subpart VVb
    For the final NSPS subpart VVb, the EPA estimates this final action 
will cost approximately $7.7 million in total capital costs and $1.1 
million per year in total annualized costs (including product 
recovery). More information about the estimated cost of this final 
action for NSPS subpart VVb can be found in the document titled CAA 
111(b)(1)(B) review for the SOCMI Equipment Leaks NSPS Subpart VVa (see 
Docket Item No. EPA-HQ-OAR-2022-0730-0096).
5. NSPS Subparts IIIa, NNNa, and RRRa
    For the final NSPS subparts IIIa, NNNa, and RRRa, the EPA estimates 
this final action will cost approximately $27.8 million in total 
capital costs and $6.3 million per year in total annualized costs 
(including product recovery). More information about the estimated cost 
of this final action for NSPS subparts IIIa, NNNa, and RRRa can be 
found in the document titled CAA 111(b)(1)(B) review for the SOCMI air 
oxidation unit processes, distillation operations, and reactor 
processes NSPS subparts III, NNN, and RRR--FINAL, which is available in 
the docket for this rulemaking.

D. What are the economic impacts?

    The EPA conducted economic impact analyses for this rulemaking, in 
a document titled Regulatory Impact Analysis for the Final New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry, which is available in the docket for 
this action. The economic impact analyses contain two parts. The 
economic impacts of the final rulemaking on small entities are 
calculated as the percentage of total annualized costs incurred by 
affected ultimate parent owners to their revenues. This ratio provides 
a measure of the direct economic impact to ultimate parent owners of 
HON, P&R I, and P&R II facilities and NSPS subpart VVb, IIIa, NNNa, and 
RRRa facilities while presuming no impact on consumers. We estimate the 
average small entity impacted by this final action will incur total 
annualized costs of 0.5 percent of their revenue, with none exceeding 
1.3 percent, not considering product recovery from compliance. With 
product recovery, the EPA estimates that the average small entity 
impacted by the rulemaking will incur total annualized costs of 0.49 
percent of their revenue, with none exceeding 1.4 percent. We estimate 
that 25 percent (2 in total) of impacted small entities will incur 
total annualized costs greater than 1 percent of their revenue, and 
none will incur total annualized costs greater than 3 percent of their 
revenue. These estimates are unchanged when including product recovery. 
This is based on a conservative estimate of costs imposed on ultimate 
parent companies, where total annualized costs are imposed on a 
facility are at the upper bound of what is possible under the rule and 
do not include product recovery as an offset to the annualized costs.
    In addition, we provide a fuller economic impact analysis using 
costs of the HON and P&R I and II NESHAP that estimates changes in 
affected chemical product price and output related to the impact of the 
compliance costs on producers and consumers of such chemical products 
for each of these final rules. There are seven chemical products 
included in the economic impact analysis--butadiene, styrene, acetone, 
acrylonitrile, ethylene dichloride, ethylene glycol, and EtO. For the 
HON, chemical product prices are estimated to increase from less than 
0.01 percent to 0.61 percent, and output by product is estimated to 
decrease by less than 0.01 percent to 0.54 percent. For the two P&R 
NESHAP, chemical product prices are estimated to increase by less than 
0.01 percent to 0.05 percent, and output by product is estimated to 
decrease by less than 0.01 percent to 0.09 percent. More explanation of 
these economic impacts can be found in the Regulatory Flexibility Act 
(RFA) section later in this preamble and in the economic impact 
analysis that is included in the RIA for this final rulemaking.

E. What are the benefits?

    The emissions controls required by these rules are expected to 
reduce emissions of a number of HAP. As stated in section V.B of this 
preamble, this final action will reduce HAP emissions by at least 1,372 
tpy and VOC emissions by 3,820 tpy from HON, P&R I, and P&R II emission 
sources as well as the NSPS SOCMI air oxidation unit processes, 
distillation operations, reactor processes, and equipment leaks sources 
(see Table 7 of this preamble). The health effects associated with the 
main HAP of concern from SOCMI (found within the HON), P&R I, and P&R 
II source categories are discussed fully in Chapter 4 of the RIA: EtO 
(Section 4.1.1), chloroprene (Section 4.1.2), benzene (Section 4.1.3), 
1,3-butadiene (Section 4.1.4), vinyl chloride (Section 4.1.5), ethylene 
dichloride (Section 4.1.6), chlorine (Section 4.1.7), maleic anhydride 
(Section 4.1.8) and acrolein (Section 4.1.9). This final action is 
projected to reduce EtO emissions from HON processes by approximately 
54 tpy and reduce chloroprene emissions from Neoprene Production 
processes subject to the P&R I NESHAP by approximately 14 tpy. We also 
estimate that the final amendments to the NESHAP will reduce other HAP 
emissions (excluding EtO and chloroprene) from the SOCMI, P&R I, and 
P&R II source categories by approximately 1,304 tpy. We also estimate 
that the final amendments to the NESHAP will reduce excess emissions of 
HAP from flares in the SOCMI and P&R I source categories by an 
additional 4,858 tpy. The Agency was unable to estimate HAP emission 
reductions for the final amendments to the NSPS in this rulemaking.

[[Page 43033]]

[GRAPHIC] [TIFF OMITTED] TR16MY24.010

    Quantifying and monetizing the economic value of reducing the risk 
of cancer and non-cancer effects is made difficult by the lack of a 
central estimate of cancer and non-cancer risk and estimates of the 
value of an avoided case of cancer (fatal and non-fatal) and morbidity 
effects. Due to methodology and data limitations, we did not attempt to 
monetize the health benefits of reductions in HAP in this analysis. 
Instead, we are providing a qualitative discussion in the RIA of the 
health effects associated with HAP emitted from sources subject to 
control under the final action. Health effects from reduced exposure to 
EtO, chloroprene, benzene, 1,3-butadiene, vinyl chloride, ethylene 
dichloride, chlorine, maleicanhydride, and acrolein are all HAP 
emissions expected to be reduced by this rule. These pollutants all 
have been associated with cancer risk is human among other acute health 
effects.
    The emission controls installed to comply with these final rules 
are also expected to reduce VOC emissions which, in conjunction with 
NOX and in the presence of sunlight, form ground-level ozone 
(O3). This section reports the estimated ozone-related 
benefits of reducing VOC emissions in terms of the number and value of 
avoided ozone-attributable deaths and illnesses.
    As a first step in quantifying O3-related human health 
impacts, the EPA consults the Integrated Science Assessment for Ozone 
(Ozone ISA) \67\ as summarized in the Technical Support Document for 
the Final Revised Cross State Air Pollution Rule Update.\68\ This 
document synthesizes the toxicological, clinical, and epidemiological 
evidence to determine whether each pollutant is causally related to an 
array of adverse human health outcomes associated with either acute 
(i.e., hours or days-long) or chronic (i.e., years-long) exposure. For 
each outcome, the Ozone ISA reports this relationship to be causal, 
likely to be causal, suggestive of a causal relationship, inadequate to 
infer a causal relationship, or not likely to be a causal relationship.
---------------------------------------------------------------------------

    \67\ U.S. EPA (2020). Integrated Science Assessment for Ozone 
and Related Photochemical Oxidants. U.S. Environmental Protection 
Agency. Washington, DC. Office of Research and Development. EPA/600/
R-20/012. Available at: https://www.epa.gov/isa/integrated-science-assessment-isa-ozone-and-related-photochemical-oxidants.
    \68\ U.S. EPA. 2021. Technical Support Document (TSD) for the 
Final Revised Cross-State Air Pollution Rule Update for the 2008 
Ozone Season NAAQS Estimating PM2.5- and Ozone-
Attributable Health Benefits. https://www.epa.gov/sites/default/files/2021-03/documents/estimating_pm2.5-_and_ozone-attributable_health_benefits_tsd.pdf.
---------------------------------------------------------------------------

    In brief, the Ozone ISA found short-term (less than one month) 
exposures to ozone to be causally related to respiratory effects, a 
``likely to be causal'' relationship with metabolic effects and a 
``suggestive of, but not sufficient to infer, a causal relationship'' 
for central nervous system effects, cardiovascular effects, and total 
mortality. The Ozone ISA reported that long-term exposures (one month 
or longer) to ozone are ``likely to be causal'' for respiratory effects 
including respiratory mortality, and a ``suggestive of, but not 
sufficient to infer, a causal relationship'' for cardiovascular 
effects, reproductive effects, central nervous system effects, 
metabolic effects, and total mortality.
    The combined total present value (PV) of the monetized human health 
benefits for this final action are $77 million and $690 million at a 3 
percent discount rate and $53 million and $475 million at a 7 percent 
discount rate. The combined total PV of the net monetized benefits 
(monetized health benefits plus monetized climate benefits minus 
climate disbenefits) for the final amendments are negative $89 million 
at the 3 percent discount rate to negative $110 million at the 7 
percent discount rate and $480 million at the 3 percent discount rate 
to $270 million at the 7 percent discount rate. The combined total 
equivalent annual value (EAV) of the benefits for the final amendments 
are negative $7 million at the 3 percent discount rate to negative $7.7 
million at the 7 percent discount rate and $40 million at the 3 percent 
discount rate to negative $34 million at the 7 percent discount rate. 
See Table 18 in section VI.A of this preamble for additional details. 
For all estimates, we summarized the monetized ozone-related health 
benefits using discount rates of 3 percent and 7 percent for the 15-
year analysis period of these rules discounted back to 2023 rounded to 
2 significant figures. We present two benefits estimates that are 
separated by the word ``and'' to signify that they are

[[Page 43034]]

two separate estimates. The estimates do not represent lower- and 
upper-bound estimates. For a full explanation of why we present 
monetized benefits estimates in this way, please refer to Chapter 4 of 
the RIA. For the full set of underlying calculations see the benefits 
workbook in the RIA, which is available in the docket for this 
rulemaking. In addition, we include the monetized disbenefits \69\ 
(i.e., negative effects) from additional CO2 and 
NOX emissions, which occur with the HON, the P&R I NESHAP, 
and NSPS IIIa, NNNa, and RRRa, but not the P&R II NESHAP or NSPS 
subpart VVb since there are no additional CO2 emissions as a 
result of these two final rules.
---------------------------------------------------------------------------

    \69\ Monetized climate benefits and disbenefits are based on 
changes (increases) in CO2 and N2O emissions 
and decreases in CH4 emissions and are calculated using 
three different estimates of the social cost of each greenhouse gas 
(SC-GHG) (2.5 percent, 2 percent, and 1.5 percent discount rates). 
For the presentational purposes, we show the benefits and 
disbenefits associated with the SC-GHG at a 2 percent discount rate.
---------------------------------------------------------------------------

1. HON
    The PV of the monetized human health benefits for the HON are $70 
million and $630 million at a 3 percent discount rate and $48 million 
and $420 million at a 7 percent discount rate. The PV of the net 
monetized benefits (monetized health benefits plus monetized climate 
benefits minus climate disbenefits) \70\ for the final amendments for 
the HON are negative $70 million at the 3 percent discount rate to 
negative $92 million at the 7 percent discount rate and $490 million at 
the 3 percent discount rate to $280 million at the 7 percent discount 
rate. The EAV of the benefits for the final amendments for the HON are 
negative $5.1 million at the 3 percent discount rate to negative $5.8 
million at the 7 percent discount rate and $42 million at the 3 percent 
discount rate to negative $35 million at the 7 percent discount rate. 
In addition, this rule will provide unmonetized benefits from the 
reduction of 1,107 tons of HAP emission reductions. This includes 
positive health effects from reduced exposure to EtO, chloroprene, 
benzene, 1,3-butadiene, vinyl chloride, ethylene dichloride, chlorine, 
maleicanhydride, and acrolein.
---------------------------------------------------------------------------

    \70\ Climate disbenefit estimates include CO2 and 
N2O increases in emissions. Climate benefit estimates 
include methane decreases in emissions.
---------------------------------------------------------------------------

2. P&R I NESHAP
    The PV of the monetized human health benefits for the P&R I NESHAP 
are negative $0.2 million and negative $1.7 million at a 3 percent 
discount rate and negative $0.2 million and negative $1.5 million at a 
7 percent discount rate. The PV of the net monetized benefits 
(monetized health benefits plus monetized climate benefits minus 
monetized climate disbenefits) for the final amendments for the P&R I 
NESHAP are negative $22 million at the 3 percent discount rate to 
negative $22 million at the 7 percent discount rate and negative $24 
million at the 3 percent discount rate to negative $24 million at the 7 
percent discount rate. The EAV of the benefits for the final amendments 
for the P&R I NESHAP are negative $1.7 million at the 3 percent 
discount rate to negative $1.7 million at the 7 percent discount rate 
and negative $1.8 million at the 3 percent discount rate to negative 
$1.8 million at the 7 percent discount rate. In addition, this rule 
will provide unmonetized benefits from 264 tpy of HAP reductions, 
including an approximate 14 tpy reduction in chloroprene emissions.
3. P&R II NESHAP
    The PV of the net monetized benefits (monetized health benefits 
plus monetized climate benefits minus monetized climate disbenefits) 
for the final amendments for the P&R II NESHAP are zero since there are 
minimal VOC emission reductions (no more than 1 tpy), and there are no 
changes in climate-related emissions (CO2, methane, 
N2O).
4. NSPS Subpart VVb
    For the final NSPS subpart VVb, the EPA the EPA elected to use the 
benefit per-ton (BPT) approach because we cannot be confident of the 
location of new facilities that would be subject to these final NSPS, 
the EPA elected to use the BPT approach. BPT estimates provide the 
total monetized human health benefits (the sum of premature mortality 
and premature morbidity) of reducing one ton of the VOC precursor for 
ozone from a specified source. Specifically, in this analysis, we 
multiplied the estimates from the SOCMI sector by the corresponding 
emission reductions. Also, there are no climate benefits or disbenefits 
associated with this final NSPS. Thus, all monetized benefits are human 
health benefits from VOC reductions. The PV of the monetized human 
health benefits from this subpart is $1.3 million and $12 million at a 
3 percent discount rate and $0.9 million and $7.9 million at a 7 
percent discount rate. The EAV of the benefits for the final NSPS 
subpart VVb are $0.10 million at the 3 percent discount rate to $0.09 
million at the 7 percent discount rate and $0.93 million at the 3 
percent discount rate to $0.82 million at the 7 percent discount rate.
5. NSPS Subpart IIIa, NNNa, and RRRa
    For the final NSPS subparts IIIa, NNNa, and RRRa, the EPA elected 
to use the BPT approach because we cannot be confident of the location 
of new facilities that would be subject to these final NSPS. BPT 
estimates provide the total monetized human health benefits (the sum of 
premature mortality and premature morbidity) of reducing one ton of the 
VOC precursor for ozone from a specified source. Specifically, in this 
analysis, we multiplied the estimates from the SOCMI sector by the 
corresponding emission reductions. The PV of the monetized human health 
benefits from these three subparts are $6 million and $54 million at a 
3 percent discount rate and $5.3 million and $47 million at a 7 percent 
discount rate.
    We then add these monetized human health benefits to the monetized 
climate benefits and disbenefits to provide a total estimate of 
monetized benefits for these final NSPS. The PV of the net monetized 
benefits (monetized health benefits plus monetized climate benefits 
minus monetized climate disbenefits) for the final NSPS subparts IIIa, 
NNNa, and RRRa are negative $8 million and negative 56 million at the 3 
percent discount rate and negative $4 million and negative $46 million 
at the 7 percent discount rate. The EAV of the benefits for the final 
NSPS subparts IIIa, NNNa, and RRRa are negative $0.6 million at the 3 
percent discount rate and negative $0.3 million at the 7 percent 
discount rate and negative $4.7 million at the 3 percent discount rate 
and negative $4.9 million at the 7 percent discount rate.

F. What analysis of environmental justice did we conduct?

    For purposes of analyzing regulatory impacts, the EPA relies upon 
its June 2016 ``Technical Guidance for Assessing Environmental Justice 
in Regulatory Analysis,'' which provides recommendations that encourage 
analysts to conduct the highest quality analysis feasible, recognizing 
that data limitations, time, resource constraints, and analytical 
challenges will vary by media and circumstance. The Technical Guidance 
states that a regulatory action may involve potential EJ concerns if it 
could: (1) create new disproportionate impacts on communities with EJ 
concerns; (2) exacerbate existing disproportionate impacts on 
communities with EJ concerns; or (3) present opportunities to address 
existing disproportionate impacts on communities with EJ concerns 
through this action under development.

[[Page 43035]]

    The EPA's EJ technical guidance states that ``[t]he analysis of 
potential EJ concerns for regulatory actions should address three 
questions: (A) Are there potential EJ concerns associated with 
environmental stressors affected by the regulatory action for 
population groups of concern in the baseline? (B) Are there potential 
EJ concerns associated with environmental stressors affected by the 
regulatory action for population groups of concern for the regulatory 
option(s) under consideration? (C) For the regulatory option(s) under 
consideration, are potential EJ concerns created or mitigated compared 
to the baseline?'' \71\
---------------------------------------------------------------------------

    \71\ ``Technical Guidance for Assessing Environmental Justice in 
Regulatory Analysis'', U.S. EPA, June 2016. Quote is from Section 
3--Key Analytic Considerations, page 11.
---------------------------------------------------------------------------

    The environmental justice analysis is presented for the purpose of 
providing the public with as full as possible an understanding of the 
potential impacts of this final action. The EPA notes that analysis of 
such impacts is distinct from the determinations finalized in this 
action under CAA sections 111 and 112, which are based solely on the 
statutory factors the EPA is required to consider under those sections.
1. SOCMI Source Category Demographics
    For the SOCMI source category, the EPA examined the potential for 
the 195 HON facilities (for which the EPA had HAP emissions 
inventories) to pose concerns to communities living in proximity to 
facilities, both in the baseline and under the control option 
established in this final action. Specifically, the EPA analyzed how 
demographics and risk are distributed both pre- and post-control. The 
methodology and detailed results of the demographic analysis are 
presented in the document titled Analysis of Demographic Factors for 
Populations Living Near Hazardous Organic NESHAP (HON) Operations--
Final, which is available in the docket for this rulemaking.
    To examine the potential for environmental justice concerns, the 
EPA conducted three different demographic analyses: a baseline 
proximity analysis, baseline cancer risk-based analysis (i.e., before 
implementation of any controls required by this final action), and 
post-control cancer risk-based analysis (i.e., after implementation of 
the controls required by this final action). The baseline proximity 
demographic analysis is an assessment of individual demographic groups 
in the total population living within 10 km (~6.2 miles) and 50 km (~31 
miles) of the facilities. The baseline risk-based demographic analysis 
is an assessment of risks to individual demographic groups in the 
population living within 10 km and 50 km of the facilities prior to the 
implementation of any controls required by this final action 
(``baseline''). The post-control risk-based demographic analysis is an 
assessment of risks to individual demographic groups in the population 
living within 10 km and 50 km of the facilities after implementation of 
the controls required by this final action (``post-control''). In this 
preamble, we focus on the results from the demographic analyses using a 
10 km radius because this buffer distance encompasses all the facility 
maximum individual risk (MIR) locations, captures 97 percent of the 
population with baseline cancer risks greater than or equal to 50-in-1 
million from SOCMI source category emissions, and captures 100 percent 
of the population with such baseline risks greater than 100-in-1 
million. The results of the demographic analyses for populations living 
within 50 km of facilities are included in the document titled Analysis 
of Demographic Factors for Populations Living Near Hazardous Organic 
NESHAP (HON) Operations--Final, which is available in the docket for 
this rulemaking.
    For all three demographic analyses, the affected populations (i.e., 
those living within 10 km of the facilities) are compared to the 
national population. The total population, population percentages, and 
population count for each demographic group for the entire U.S. 
population are shown in the column titled ``Nationwide Average for 
Reference'' in Tables 8 through 10 of this preamble. These national 
data are provided as a frame of reference to compare the results of the 
baseline proximity analysis, the baseline cancer risk-based analysis, 
and the post-control cancer risk-based analysis.
    The results of the baseline proximity analysis indicate that a 
total of 9.3 million people live within 10 km of the 195 HON 
facilities. The percent of the population that is Black (25 percent) is 
more than double the national average (12 percent), and the percent of 
the population that is Hispanic or Latino (22 percent) is also higher 
than the national average (19 percent). The percent of people living 
below the poverty level and the percent of people over the age of 25 
without a high school diploma are higher than the national averages. 
The results of the baseline proximity analysis indicate that the 
proportion of other demographic groups living within 10 km of HON 
facilities is similar to or below the national average.
    The baseline cancer risk-based demographic analysis, which focuses 
on populations that have higher cancer risks, suggests that Hispanic/
Latino individuals and Black individuals living near the facilities are 
overrepresented with respect to the national average at all cancer risk 
levels greater than 1-in-1 million. In addition, the percent of 
households with linguistic isolation (in which all household members 
over the age of 14 only have limited English proficiency) increases as 
the Hispanic/Latino population increases. At all risk levels greater 
than or equal to 1-in-1-million, in cases where the percentage of the 
population below the poverty level is 1.5 to 2 times the national 
average, these populations are also above the national averages for 
Black, American Indian or Alaska Native, Hispanic/Latino, or Other 
Race/Multiracial populations.
    The post-control risk-based demographic analysis shows that the 
controls required by this final action will notably reduce the number 
of people who are exposed to cancer risks resulting from SOCMI source 
category emissions at all risk levels. At greater than or equal to a 
cancer risk of 1-in-1 million, the number of individuals exposed will 
decrease from 2.8 million to 2.7 million. At greater than or equal to a 
cancer risk of 50-in-1 million, the number of individuals exposed will 
decrease from 300,000 to 30,000. And after the control is implemented, 
there will be no people who are exposed to cancer risks greater than 
100-in-1 million resulting from SOCMI source category emissions. 
Although all demographic populations will see reductions in the number 
of individuals exposed at each level of risk, there will be individuals 
who still remain at a cancer risk greater than or equal to 1-in-1 
million or greater than or equal to 50-in-1 million risk post-control. 
The demographic composition of those individuals still exposed to risk 
greater than or equal to 1-in-1 million will be similar to the 
demographic composition of the individuals exposed at baseline. At the 
greater than or equal to 50-in-1 million risk level, the percentages of 
most demographic populations will be similar to the national average 
percentages with the exception of the Hispanic/Latino population, which 
will still be overrepresented with respect to the national average. At 
the greater than 100-in-1 million risk level, there will be no 
individuals exposed to cancer risk post-control, so there will be no 
disparities among demographic groups at this risk level. The actions of 
this

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final rulemaking will improve human health of current and future 
populations that live near these facilities. For more details see the 
remainder of this section.
a. Baseline Proximity Analysis
    The column titled ``Baseline Proximity Analysis for Pop. Living 
within 10 km of HON Facilities'' in Tables 8 through 10 of this 
preamble shows the share and count of people for each of the 
demographic categories for the total population living within 10 km 
(~6.2 miles) of HON facilities. These are the results of the baseline 
proximity analysis and are repeated in Tables 8 through 10 of this 
preamble for easy comparison to the risk-based analyses discussed 
later.
    Approximately 9.3 million people live within 10 km of the 195 HON 
facilities assessed. The results of the proximity demographic analysis 
indicate that the percent of the population that is Black (25 percent, 
2.35M people) is more than double the national average (12 percent). 
The percent of the population that is Hispanic or Latino (22 percent, 
2M people) is higher than the national average (19 percent). The 
percent of people living below the poverty level (19 percent, 1.75M 
people) and percent of people over the age of 25 without a high school 
diploma (16 percent, 1.5M people) are higher than the national averages 
(13 percent and 12 percent, respectively). The baseline proximity 
analysis indicates that the proportion of other demographic groups 
living within 10 km of HON facilities is similar to or below the 
national average.
b. Baseline Risk-Based Demographics
    The baseline risk-based demographic analysis results are shown in 
the ``baseline'' column of Tables 8 through 10 of this preamble. This 
analysis focused on the populations living within 10 km (~6.2 miles) of 
the HON facilities with estimated cancer risks greater than or equal to 
1-in-1 million resulting from SOCMI source category emissions (Table 8 
of this preamble), greater than or equal to 50-in-1 million (Table 9 of 
this preamble), and greater than 100-in-1 million (Table 10 of this 
preamble). The risk analysis indicated that emissions from the source 
category, prior to the controls required in this final action, expose 
2.8 million people living near 111 facilities to a cancer risk greater 
than or equal to 1-in-1 million, 322,000 people living near 21 
facilities to a cancer risk greater than or equal to 50-in-1 million, 
and 83,000 people living near 8 facilities to a cancer risk greater 
than 100-in-1 million.
    In the baseline, there are 2.8 million people living around 111 HON 
facilities with a cancer risk greater than or equal to 1-in-1 million 
resulting from SOCMI source category emissions. The 111 HON facilities 
are located across 17 states, but two-thirds of them are located in 
Texas and Louisiana (50 in Texas and 33 in Louisiana). Ninety percent 
of the people with risks greater than or equal to 1-in-1 million are 
living around 29 of the 111 HON facilities. All but three of these 29 
facilities are located in Texas and Louisiana. The percent of the 
baseline population with estimated cancer risks greater than or equal 
to 1-in-1 million who are Black (25 percent, 692,000 people) is well 
above the average percentage of the national population that is Black 
(12 percent). The Black population living within 10 km of two 
facilities in Louisiana account for about a quarter of the total Black 
population with risks greater than or equal to 1-in-1 million resulting 
from SOCMI source category emissions.
    The percent of the population with cancer risks greater than or 
equal to 1-in-1 million resulting from SOCMI source category emissions 
prior to the controls required in this final action that is Hispanic or 
Latino (34 percent, 958,000 people) is significantly higher than that 
in the baseline proximity analysis (22 percent, 2 million people) and 
well above the national average (19 percent). The population around an 
Illinois facility is over 75 percent Hispanic or Latino, and accounts 
for a quarter of the Hispanic/Latino population with risks greater than 
or equal to 1-in-1 million resulting from SOCMI source category 
emissions. Another group of 5 facilities in the Houston/Channelview 
Texas area have local populations that are between 60 and 90 percent 
Hispanic/Latino, and those communities account for 31 percent of the 
Hispanic/Latino population with risks greater than or equal to 1-in-1 
million resulting from SOCMI source category emissions. The percent of 
the population that is linguistically isolated in the baseline with 
cancer risks greater than or equal to 1-in-1 million (8 percent, 
228,000 people) is higher than the percentage in the baseline proximity 
analysis (5 percent, 510,000 people). The areas with the highest 
Hispanic/Latino population are some of those with the highest percent 
linguistic isolation.
    Overall, the percent of the baseline population that is American 
Indian or Alaska Native with risks greater than or equal to 1-in-1 
million resulting from SOCMI source category emissions (0.2 percent) is 
well below the national average (0.7 percent). The population with 
baseline risks resulting from SOCMI source category emissions greater 
than or equal to 1-in-1 million have a percent American Indian or 
Alaska Native population that is more than 2 times the national 
average. These facilities are located in Texas (3), Louisiana, Montana, 
Illinois, and Kansas.
    The percent of the population below the poverty level with cancer 
risks greater than or equal to 1-in-1 million resulting from SOCMI 
source category emissions (18 percent, 513,000 people) is above the 
national average (13 percent). The percent of the population living 
below the poverty level within 10 km of 19 facilities is twice the 
national average. The percent of the population over 25 years old 
without a high school diploma with cancer risks greater than or equal 
to 1-in-1 million resulting from SOCMI source category emissions (20 
percent, 561,000 people) is greater than the national average (13 
percent) as well as greater than the overall percent of the population 
living near HON facilities who are over 25 years old without a high 
school diploma (16 percent, 1.5 million people).
    In the baseline, there are 322,000 people living around 21 HON 
facilities with a cancer risk greater than or equal to 50-in-1 million 
resulting from SOCMI source category emissions. The 21 HON facilities 
are located across 6 states, but two-thirds of them are located in 
Texas and Louisiana. Ninety-six percent of the people with risks 
greater than or equal to 50-in-1 million resulting from SOCMI source 
category emissions live around 5 HON facilities, which are located in 
Texas or Louisiana. The percent of the population that is Black with 
baseline cancer risk greater than or equal to 50-in-1 million resulting 
from SOCMI source category emissions (18 percent, 59,000 people) is 
above the national average (12 percent) but is significantly lower than 
the percent of the population that is Black with risks greater than or 
equal to 1-in-1 million resulting from SOCMI source category emissions 
(25 percent, 692,000 people). The percentage of Black individuals is 
greater than the national average near over half of the facilities (12 
facilities) where cancer risk is greater than 50-in-1 million resulting 
from HON source category emissions. The populations near two facilities 
in Texas account for about 70 percent of the number of Black 
individuals with risks greater than or equal to 50-in-1 million 
resulting from SOCMI source category emissions.
    The percentage of the population that is Hispanic/Latino with risks 
greater than or equal to 50-in-1 million resulting from SOCMI source 
category emissions (25 percent, 81,000 people) is

[[Page 43037]]

similar to the percentage of the population that is Hispanic/Latino in 
the total population living within 10 km of the facilities (22 
percent). The percent of population that is Hispanic/Latino with cancer 
risks greater than or equal to 50-in-1 million resulting from SOCMI 
source category emissions is above the national average at over half of 
the facilities (13 facilities). The population near three facilities in 
Texas accounts for about 80 percent of the number of Latino/Hispanic 
people with risks greater than or equal to 50-in-1 million resulting 
from SOCMI source category emissions.
    Overall, the percent of the population that is American Indian or 
Alaska Native with risks greater than or equal to 50-in-1 million 
resulting from SOCMI source category emissions (0.2 percent) is below 
the national average (0.7 percent). Populations near four facilities 
with baseline risks greater than or equal to 50-in-1 million resulting 
from SOCMI source category emissions have a percent American Indian or 
Alaska Native population that is more than 2 times the national 
average. These facilities are located in Texas (3) and Louisiana.
    The percentage of the population with cancer risks resulting from 
SOCMI source category emissions greater than or equal to 50-in-1 
million that are below the poverty level (15 percent), over 25 years 
old without a high school diploma (15 percent), or are linguistically 
isolated (5 percent) are similar to or slightly above the respective 
national averages. Of the population with risks greater than or equal 
to 50-in-1 million resulting from SOCMI source category emissions, the 
percentage of the population below the poverty level is twice the 
national average near five facilities. For all 5 of these facilities, 
the percentage of the population is also 2 times the national average 
percentage for at least one race/ethnic demographic category.
    In the baseline, there are 83,000 people living around 8 HON 
facilities with a cancer risk resulting from SOCMI source category 
emissions greater than 100-in-1 million. These 8 HON facilities are 
located in Texas and Louisiana. The percent of the population that is 
Black with baseline cancer risk greater than 100-in-1 million resulting 
from SOCMI source category emissions (14 percent) is just above the 
national average (12 percent). The percentage of the Black population 
with cancer risks greater than 100-in-1 million resulting from SOCMI 
source category emissions is between 2 to 4 times greater than the 
national average at three facilities in Texas and one in Louisiana.
    The percentage of the population that is Hispanic/Latino with risks 
greater than 100-in-1 million resulting from SOCMI source category 
emissions (26 percent, 22,000 people) is above the national average (19 
percent) and is similar to the share of the population that is 
Hispanic/Latino with cancer risks greater than or equal to 50-in-1 
million resulting from SOCMI source category emissions (25 percent, 
81,000 people). The share of the Hispanic and Latino population with 
cancer risks greater than 100-in-1 million resulting from SOCMI source 
category emissions is between 2 to 3 times greater than the national 
average at five facilities in Texas and one in Louisiana.
    Overall, the percent of the baseline population that is American 
Indian or Alaska Native with risks greater than or equal to 100-in-1 
million resulting from SOCMI source category emissions (0.2 percent) is 
well below the National Average (0.7 percent).
    The percentage of the population with cancer risks greater than 
100-in-1 million resulting from SOCMI source category emissions that 
are below the poverty level (14 percent), over 25 without a high school 
diploma (14 percent), or linguistically isolated (5 percent) are 
similar or slightly above the respective national averages. The percent 
of the population below the poverty level is 1.5 times the national 
average at five facilities. The population living around three of these 
facilities is also 1.5 times the national average for at least one 
race/ethnic demographic category.
    In summary, the baseline risk-based demographic analysis, which 
focuses on populations that are expected to have higher cancer risks 
resulting from SOCMI source category emissions, suggests that Hispanic 
or Latino individuals are disproportionally overrepresented at all 
cancer risk levels. Specifically, the percentage of the population that 
is Hispanic/Latino is almost twice the national average at a cancer 
risk equal to or greater than 1-in-1 million and almost 1.5 times the 
national average at the 50-in-1-million and 100-in-1-million risk 
levels. Similarly, the Black population is disproportionately 
overrepresented at all cancer risk levels in the baseline risk 
analysis. The percentage of Black individuals with risks greater than 
or equal to 1-in-1 million resulting from SOCMI source category 
emissions is twice the national average and 1.5 times the national 
average at the 50-in-1-million risk level. In most cases, when the 
percentage of the population below the poverty level is greater than 
1.5 times the national average, the percentage of the population that 
is Black, American Indian or Alaska Native, Hispanic/Latino, or Other/
Multiracial is above the national average.
c. Post-Control Risk-Based Demographics
    This analysis focused on the populations living within 10 km (~6.2 
miles) of the facilities with estimated cancer risks greater than or 
equal to 1-in-1 million (Table 8 of this preamble), greater than or 
equal to 50-in-1 million (Table 9 of this preamble), and greater than 
100-in-1 million (Table 10 of this preamble) resulting from SOCMI 
source category emissions after implementation of the control options 
for HON sources investigated under the residual risk analysis as 
described in section III.B.2.a of this preamble (``post-control''). The 
results of the post-control risk-based demographics analysis are in the 
columns titled ``Post-Control'' of Tables 8 through 10 of this 
preamble. In this analysis, we evaluated how all of the controls 
required by this final action and emission reductions for HON processes 
described in this action affect the distribution of risks. This makes 
it possible to characterize the post-control risks and to evaluate 
whether the final action creates or mitigates potential environmental 
justice concerns as compared to the baseline.
    The risk analysis indicated that the number of people within 10 km 
of a facility exposed to risks greater than or equal to 1-in-1 million 
resulting from SOCMI source category emissions (Table 8 of this 
preamble) is reduced from 2.8 million people in the baseline to 
approximately 2.7 million people after implementation of the HON 
controls required by this final action. The populations with a cancer 
risk greater than or equal to 1-in-1 million resulting from SOCMI 
source category emissions are located around 111 facilities for both 
the baseline and post-control.
    The post-control population living within 10 km of a facility with 
estimated cancer risks greater than or equal to 1-in-1 million 
resulting from SOCMI source category emissions (Table 8 of this 
preamble) has similar demographic percentages to the baseline 
population with risks greater than or equal to 1-in-1 million. However, 
the number of individuals with risks greater than or equal to 1-in-1 
million resulting from SOCMI source category emissions is reduced in 
each demographic. Specifically, the percentage of the population with 
risks greater than or equal to 1-in-1 million resulting from SOCMI 
source category emissions that is

[[Page 43038]]

Black remains high at 25 percent in the post-control scenario, but the 
number of Black individuals with risks at or above 1-in-1 million is 
reduced by over 25,000 people from 692,000 in the baseline to 664,000 
in the post-control scenario.
    Similarly, the percentage of the population with risks greater than 
or equal to 1-in-1 million resulting from SOCMI source category 
emissions that is Hispanic/Latino is almost twice the national average 
in the post-control scenario (35 percent versus 19 percent), but the 
number of Hispanic/Latino individuals with risks at or above 1-in-1 
million is reduced by about 24,000 people from 958,000 in the baseline 
to 934,000 in the post-control scenario.
    The percent of the population that is American Indian or Alaska 
Native with risks greater than or equal to 1-in-1 million resulting 
from SOCMI source category emissions (0.2 percent) is below the 
national average (0.7 percent) in the post-control analysis. 
Nevertheless, there are seven facilities post-control with risks 
greater than or equal to 1-in-1 million with a percent American Indian 
or Alaska Native population that is more than 2 times the national 
average. However, the number of American Indians or Alaska Natives with 
risks greater than or equal to 1-in-1 million resulting from SOCMI 
source category emissions is reduced from 6,000 in the baseline to 
5,000 in the post-control scenario.
    The percent of the population below the poverty level is the same 
in the post-control scenario as in the baseline (18 percent), but the 
number of individuals with risks greater than or equal to 1-in-1 
million resulting from SOCMI source category emissions that are below 
the poverty level is reduced by 20,000, from 513,000 to 493,000. The 
percent of individuals over 25 years old without a high school diploma 
is the same in the post-control scenario as in the baseline (20 
percent), but the number of individuals with risks greater than or 
equal to 1-in-1 million resulting from SOCMI source category emissions 
is reduced by almost 23,000, from 561,000 to 538,000. The percentage of 
the population that is in linguistic isolation with risks greater than 
or equal to 1-in-1 million resulting from SOCMI source category 
emissions is the same in the post-control scenario (8 percent), but the 
number of individuals is reduced by almost 8,000 compared to the 
baseline, from 228,000 to 220,000.
    The risk analysis indicated that the number of people living within 
10 km of a facility and exposed to risks greater than or equal to 50-
in-1 million resulting from SOCMI source category emissions (Table 9 of 
this preamble) is reduced significantly from 322,000 people in the 
baseline to 29,000 after implementation of the controls required by 
this final action. This represents more than a 90 percent reduction in 
the number of individuals with risk greater than or equal to 50-in-1 
million when compared to the baseline. The populations living within 10 
km of a facility and with a cancer risk greater than or equal to 50-in-
1 million resulting from SOCMI source category emissions are located 
around 13 facilities in the post-control scenario, 8 fewer facilities 
than in the baseline. These 13 facilities are located in Alabama, 
Arkansas, Illinois, Kentucky, Louisiana (5 facilities), and Texas (4 
facilities). The communities within 10 km of five of those facilities 
(in Texas (3 facilities), Alabama, and Illinois) comprise 95 percent of 
the population with risks greater than or equal to 50-in-1 million 
resulting from SOCMI source category emissions.
    The number of individuals with risks greater than or equal to 50-
in-1 million is reduced significantly for each demographic category in 
the post-control scenario. Specifically, the percentage of the 
population with risks greater than or equal to 50-in-1 million 
resulting from SOCMI source category emissions that is Black decreased 
in the post-control scenario and is equal to the national average (12 
percent). The number of Black individuals with risks at or above 50-in-
1 million is reduced from 59,000 in the baseline to 4,000 post-control. 
The percentage of the population with risks greater than or equal to 
50-in-1 million resulting from SOCMI source category emissions that is 
Hispanic/Latino increased from 25 percent in the baseline to 29 percent 
post-control, but the number of Hispanic/Latino individuals with risks 
at or above 50-in-1 million is reduced from 81,000 in the baseline to 
9,000 post-control.
    Overall, the percent of the population that is American Indian or 
Alaska Native with risks greater than or equal to 50-in-1 million 
resulting from SOCMI source category emissions (0.3 percent) is well 
below the national average (0.7 percent) in the post-control scenario. 
In addition, the number of American Indians or Alaska Natives with 
risks greater than or equal to 50-in-1 million resulting from SOCMI 
source category emissions is reduced from 600 in the baseline to less 
than 100 post-control.
    The percent of the population with risks greater than or equal to 
50-in-1 million resulting from SOCMI source category emissions whose 
income is below the poverty level (11 percent) is reduced from the 
baseline (15 percent) post-control. In addition, the number of 
individuals with risks greater than or equal to 50-in-1 million 
resulting from SOCMI source category emissions who are below the 
poverty level is reduced from 47,000 to 3,000. The number of 
individuals with risks greater than or equal to 50-in-1 million 
resulting from SOCMI source category emissions that are over 25 years 
old without a high school diploma or are linguistically isolated are 
also greatly reduced post-control.
    The risk analysis indicated that the number of people living within 
10 km of a facility with risks greater than 100-in-1 million resulting 
from SOCMI source category emissions (Table 10 of this preamble) is 
reduced from 83,000 individuals in the baseline to zero individuals 
after application of the SOCMI controls required by this final action. 
Therefore, for the post-control risk-based demographic results, there 
are no greater than 100-in-1 million demographic results to discuss.
    In summary, as shown in the post-control risk-based demographic 
analysis, the controls required by this final action significantly 
reduce the number of people expected to have cancer risks greater than 
or equal to 1-in-1 million, greater than or equal to 50-in-1 million, 
and greater than 100-in-1 million resulting from SOCMI source category 
emissions. Although the number of individuals with risks greater than 
or equal to 1-in-1 million is reduced in the post-control scenario 
(reduced from 2.8 million people to 2.7 million people), populations of 
Black individuals, Hispanic/Latino individuals, those living below the 
poverty level, and those over 25 without a high school diploma remain 
disproportionately represented. Similarly, the number of individuals 
with risks greater than or equal to 50-in-1 million is reduced 
significantly in the post-control scenario (reduced from 322,000 to 
29,000), but the population of Black individuals remains 
disproportionately represented. Post-control, there are no individuals 
with risks greater than 100-in-1 million resulting from SOCMI source 
category emissions (reduced from 83,000 people to 0 people).
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BILLING CODE 6560-50-C
2. HON Whole-Facility Demographics
    As described in Section III.A.5 of this preamble, we assessed the 
facility-wide (or ``whole-facility'') risks for 195 HON facilities in 
order to compare the SOCMI source category risk to the whole-facility 
risks, accounting for HAP emissions from the entire major source and 
not just those resulting from SOCMI source category emissions at the 
major source as discussed in the previous section. The whole-facility 
risk analysis includes all sources of HAP emissions at each facility as 
reported in the NEI (described in section III.C of the preamble to the 
proposed rule). Since HON facilities tend to include HAP emissions 
sources from many source categories, the EPA conducted a whole-facility 
demographic analysis focused on post-control risks. This whole-facility 
demographic analysis characterizes the remaining risks communities face 
after implementation of the controls required in this final action for 
both the SOCMI source category and the Neoprene Production source 
category.
    The whole-facility demographic analysis is an assessment of 
individual demographic groups in the total population living within 10 
km (~6.2 miles) and 50 km (~31 miles) of the facilities. In this 
preamble, we focus on the 10 km radius for the demographic analysis 
because, based on SOCMI category emissions, this distance includes all 
the facility MIR locations, includes 97 percent of the population with 
cancer risks greater than or equal to 50-in-1 million, and includes 100 
percent of the population with risks greater than 100-in-1 million. The 
results of the whole-facility demographic analysis for populations 
living within 50 km are included in the document titled Analysis of 
Demographic Factors for Populations Living Near Hazardous Organic 
NESHAP (HON) Operations: Whole Facility Analysis--Final, which is 
available in the docket for this rulemaking.
    The whole-facility demographic analysis post-control results are 
shown in Table 11 of this preamble. This analysis focused on the 
populations living within 10 km of the HON facilities with estimated 
whole-facility post-control cancer risks greater than or equal to 1-in-
1 million, greater than or equal to 50-in-1 million, and greater than 
100-in-1 million. The risk analysis indicated that all emissions from 
the HON facilities, after the reductions imposed by the final rule, 
expose a total of about 3 million people living around 140 facilities 
to a cancer risk greater than or equal to 1-in-1 million, 79,000 people 
living around 24 facilities to a cancer risk greater than or equal to 
50-in-1 million, and 2,900 people living around 4 facilities to a 
cancer risk greater than 100-in-1 million.
    When the HON whole-facility populations are compared to the SOCMI 
source category populations in the post-control scenarios, we see 
400,000 additional people with risks greater than or equal to 1-in-1 
million, 50,000 additional people with risks greater than or equal to 
50-in-1 million, and 2,900 additional people with risks greater than 
100-in-1 million. With the exception of a smaller percentage of 
affected Hispanic/Latino individuals (35 percent for category versus 33 
percent whole-facility), the demographic distribution of the whole-
facility population with risks greater than or equal to 1-in-million is 
similar to the source category population with risks greater than or 
equal to 1-in-1 million in the post-control scenario. The population 
with risks greater than or equal to 50-in-1 million in the whole-
facility analysis has a lower percent of Hispanic/Latino individuals 
than the category population with risks greater than or equal to 50-in-
1 million (25 percent versus 29 percent). The percentage of the 
population with risks greater than or equal to 50-in-1 million that is 
below the poverty level or over 25 years old without a high school 
diploma is higher for the whole-facility post-control population than 
for the category post-control population (14 percent versus 11 
percent). The SOCMI source category emissions analysis indicated that 
there are no people with post-control risks greater than 100-in-1 
million. Based on results from the whole-facility emissions analysis, 
there are 2,900 people with post-control risks greater than 100-in-
million. The increased cancer risk for most of these 2,900 people is 
driven by EtO emissions from non-HON processes and whole-facility 
emissions from the neoprene production facility (a combination of the 
remaining SOCMI category risk and Neoprene Production category risk at 
this facility). The percent of the population in the whole-facility 
analysis with post-control risks greater than 100-in-1 million that is 
Black (25 percent, 700 individuals) is well above the national average 
(12 percent). In addition, the percent of the population in the whole-
facility analysis with a post control risk greater than 100-in-1 
million that is below the poverty level (22 percent, 600 individuals), 
and the percent of the population that is over 25 years old without a 
high school diploma (27 percent, 800 individuals) are above the 
national average (13

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percent and 12 percent, respectively). We note that as further 
discussed in section IV.B of this preamble, the EPA is finalizing a 
fenceline action level of 0.2 [micro]g/m\3\ for EtO for the whole-
facility. As such, we believe that once fenceline monitoring is fully 
implemented, that whole-facility post-control risks will be lower and 
the number of people presented in Table 11 of this preamble at each 
risk threshold will be lower.
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3. Neoprene Production Source Category Demographics
    For the Neoprene Production source category subject to the P&R I 
NESHAP, the EPA examined the potential for the one neoprene production 
facility to pose environmental justice concerns to communities both in 
the baseline and under the control option required in this final 
action. Specifically, the EPA analyzed how demographics and risk are 
distributed both pre- and post-controls. The methodology and detailed 
results of the demographic analysis are presented in a technical 
report, Analysis of Demographic Factors for Populations Living Near 
Neoprene Production Operations--Final, which is available in the docket 
for this rulemaking.
    To examine the potential for environmental justice concerns in the 
pre-control baseline, the EPA conducted three different demographic 
analyses: a baseline proximity analysis, baseline cancer risk-based 
analysis, and post-control cancer risk-based analysis. These analyses 
(total baseline, baseline risk, and post-control risks) assessed the 
demographic groups in the populations living within 5 km (~3.1 miles) 
and 50 km (~31 miles) of the facility. For the Neoprene Production 
source category, we focus on the 5 km radius for the demographic 
analysis because it encompasses the facility MIR location and captures 
100 percent of the population with cancer risks resulting from Neoprene 
Production source category emissions greater than or equal to 50-in-1 
million and greater than 100-in-1 million. The results of the proximity 
analysis for populations living within 50 km are included in the 
technical report included in the docket for this final action. 
Nationwide average demographics data are provided as a frame of 
reference.
    The results of the proximity demographic analysis indicate that a 
total of about 29,000 people live within 5 km of the Neoprene facility. 
The percent of the population that is Black is more than four times the 
national average. The percent of people living below the poverty level 
is almost double the national average.
    The baseline risk-based demographic analysis indicates that Black 
individuals are disproportionally overrepresented at all cancer risk 
levels resulting from Neoprene Production source category emissions 
(percent of Black individuals range from 5 to 7 times the national 
average percent). The percent of the population that is below the 
poverty level is twice the national average within 5 km of the Neoprene 
facility.
    The post-control risk-based demographic analysis indicates that the 
controls required for Neoprene Production source category in this final 
action do not reduce the number of people with cancer risks resulting 
from Neoprene Production source category emissions greater than or 
equal to 1-in-1 million at the 5 km distance. However, the controls do 
significantly reduce the number of people with risks resulting from 
Neoprene Production source category emissions greater than or equal to 
1-in-1 million within 50 km. The populations with risks resulting from 
Neoprene Production source category emissions greater than or equal to 
50-in-1 million and greater than 100-in-1 million are reduced at all 
distances by more than 88 percent by the controls for the Neoprene 
Production source category under consideration. In the post-control 
scenario, there are no people with risks resulting from Neoprene 
Production source category emissions greater than 100-in-1 million.
a. Baseline Proximity Analysis
    The column titled ``Total Population Living within 5 km of Neoprene 
Facility'' in Tables 12 through 14 of this preamble shows the 
demographics for the total population living within 5 km (~3.1 miles) 
of the neoprene facility. A total of about 29,000 people lives within 5 
km of the one neoprene facility. The results of the proximity 
demographic analysis indicate that the percentage of the population 
that is Black (56 percent, 16,000 people) is more than four times the 
national average (12 percent). The percentage of people living below 
the poverty level (23 percent, 6,500 people) and those over the age of 
25 without a high school diploma (16 percent, 4,500 people) are higher 
than the national averages (13 percent and 12 percent, respectively). 
The baseline proximity analysis indicates that the proportion of other 
demographic groups living within 5 km of the neoprene facility is 
similar to or below the national average.
b. Baseline Risk-Based Demographics
    The baseline risk-based demographic analysis results are shown in 
the ``baseline'' column of Tables 12 through 14 of this preamble. This 
analysis focused on the populations living within 5 km (~3.1 miles) of 
the neoprene facility with estimated cancer risks resulting from 
Neoprene Production source category emissions greater than or equal to 
1-in-1 million (Table 12 of this preamble), greater than or equal to 
50-in-1 million (Table 13 of this preamble), and greater than 100-in-1 
million (Table 14 of this preamble) in the absence of the reductions we 
are finalizing in this action.
    In the baseline, emissions from the Neoprene Production source 
category expose all individuals within 5 km of the facility (29,000 
people) to a cancer risk greater than or equal to 1-in-1 million. Since 
the entire population within 5 km are exposed to risks greater than or 
equal to 1-in-1 million, the demographics of the baseline at-risk 
population are the same as the total baseline population. Specifically, 
a high percentage of the population is Black (56 percent versus 12 
percent nationally), below the poverty line (23 percent versus 13 
percent nationally), and over the age of 25 without a high school 
diploma (16 percent versus 12 percent nationally). The percentages of 
other demographic groups within the population with risks resulting 
from Neoprene Production source category emissions greater than or 
equal to 1-in-1 million living within 5 km of the neoprene facility are 
similar to or below the national average. Within 50 km (~31 miles) of 
the facility, about 70 percent of the population (687,000 people of the 
1 million total within 50 km) is exposed to a cancer risk resulting 
from Neoprene Production source category emissions greater than or 
equal to 1-in-1 million. Additional details on the 50 km results can be 
found in the demographics report located in the docket.
    The risk-based demographics analysis indicates that emissions from 
the source category, prior to the reductions we are finalizing in this 
action, expose about 13,000 individuals within 5 km of the facility to 
a cancer risk greater than or equal to 50-in-1 million (about half of 
the total population within 5 km). As seen at the lower risk level of 
greater than or equal to 1-in-1 million, the population with risks 
greater than or equal to 50-in-1 million has a very high percentage of 
Black individuals; that percent is almost 6 times the national average 
(68 percent versus 12 percent nationally). The percentage of the 
population that is below the poverty line is more than double the 
national average (27 percent versus 13 percent nationally), and the 
percentage of the population that is over the age of 25 without a high 
school diploma is 1.5 times the national average (18 percent versus 12 
percent nationally). The percentages of other demographic groups within 
the population with risks resulting from Neoprene Production source 
category emissions greater than or equal to 50-in-1 million living 
within 5 km of the Neoprene facility are similar to or below the 
national average.
    In the baseline, there are 2,000 people living within 5 km of the 
Neoprene

[[Page 43048]]

facility with a cancer risk greater than 100-in-1 million resulting 
from Neoprene Production source category emissions. The percent of the 
population that is Black with baseline cancer risk greater than 100-in-
1 million (85 percent, 1,750 people) is over 7 times the national 
average (12 percent). The percentage of the population with cancer 
risks greater than 100-in-1 million that is below the poverty level (31 
percent, 600 people) is about 2.5 times the national average (13 
percent). The percent of the population that is over 25 without a high 
school diploma (14 percent, 300 people) is just above the national 
average (12 percent).
    In summary, the baseline risk-based demographic analysis, which 
focuses on those specific locations that are expected to have higher 
cancer risks in the baseline, indicates that Black individuals are 
disproportionally overrepresented at all cancer risk levels. 
Specifically, at all risk levels, the percent of the population that is 
Black is 5 to 7 times the national average and the percent of the 
population that is below the poverty level is twice the national 
average within 5 km of the neoprene production facility.
c. Post-Control Risk-Based Demographics
    This analysis focused on the populations living within 5 km (~3.1 
miles) of the facility with estimated cancer risks resulting from 
Neoprene Production source category emissions greater than or equal to 
1-in-1 million (Table 12 of this preamble), greater than or equal to 
50-in-1 million (Table 13 of this preamble), and greater than 100-in-1 
million (Table 14 of this preamble) after implementation of the 
Neoprene Production source category control options as described in 
section III.B.2.b of this preamble. The results of the post-control 
risk-based demographics analysis are in the columns titled ``Post-
Control'' of Tables 12 through 14 of this preamble. In this analysis, 
we evaluated how all of the controls required by this final action and 
emission reductions for the Neoprene Production source category 
described in this action affect the distribution of risks. This makes 
it possible to characterize the post-control risks and to evaluate 
whether the final action creates or mitigates potential environmental 
justice concerns as compared to the baseline.
    The risk analysis indicated that the number of people exposed to 
risks resulting from Neoprene Production source category emissions 
greater than or equal to 1-in-1 million within 5 km of the facility 
(Table 12 of this preamble) is unchanged from the baseline (29,000 
people). Therefore, the population living within 5 km of the facility 
with estimated cancer risks greater than or equal to 1-in-1 million in 
the post-control scenario (Table 12 of this preamble) has the same 
demographic percentages as the total population in the proximity 
analysis and the population with risks greater than or equal to 1-in-1 
million in the baseline risk analysis. Specifically, the percentage of 
the population with risks resulting from Neoprene Production source 
category emissions in the post-control analysis that is greater than or 
equal to 1-in-1 million and is Black (56 percent) is almost 5 times the 
national average (12 percent), and the percent below the poverty level 
(23 percent) is almost 2 times the national average (13 percent). 
However, after control, the number of people exposed to risk greater 
than or equal to 1-in-1 million within 50 km (~31 miles) of the 
facility is significantly reduced from 687,000 to 58,000.
    The risk analysis indicated that the number of people living within 
5 km of the facility and exposed to risks greater than or equal to 50-
in-1 million resulting from Neoprene Production source category 
emissions (Table 13 of this preamble) is reduced significantly from 
about 13,000 people in the baseline to 1,450 people after 
implementation of the controls required by this final action. This 
represents more than an 88 percent reduction in the size of the 
populations at risk when compared to the baseline population. The post-
control population living within 5 km of the facility with estimated 
cancer risks greater than or equal to 50-in-1 million for post-control 
(Table 13 of this preamble) is almost entirely Black (92 percent). The 
number of Black individuals with risks greater than or equal to 50-in-1 
million is reduced from about 9,000 in the baseline to 1,350 people 
post-control. Similarly, the post-control population with risks greater 
than or equal to 50-in-1 million has a high percent of people below 
poverty (33 percent). The number of people with risks greater than or 
equal 50-in-1 million that are below the poverty level is reduced from 
3,400 in the baseline to 500 people post-control.
    The risk analysis indicated that the number of people living within 
5 km of the facility and exposed to risks greater than 100-in-1 million 
resulting from Neoprene Production source category emissions (Table 14 
of this preamble) is reduced from over 2,000 people in the baseline to 
zero people after application of the controls required by this final 
action. Therefore, for the post-control risk-based demographics, there 
are no people with risks above 100-in-1 million resulting from Neoprene 
Production source category emissions.
    In summary, as shown in the post-control risk-based demographic 
analysis, the controls required by this final action do not reduce the 
number of people expected to have cancer risks resulting from Neoprene 
Production source category emissions greater than or equal to 1-in-1 
million at the 5 km distance. The controls do significantly reduce the 
number of people with risks resulting from Neoprene Production source 
category emissions greater than or equal to 1-in-1 million within 50 
km. In the post-control population with risks greater than or equal to 
1-in-1 million, Black individuals and those living below the poverty 
level remain disproportionately represented. For the populations with 
risks greater than or equal to 50-in-1 million and greater than 100-in-
1 million, the controls under consideration reduce the at-risk 
populations by more than 88 percent at all distances. In the post-
control population with risks greater than or equal to 50-in-1 million, 
Black individuals and those living below the poverty level remain 
disproportionately represented. Post-control, there are no people with 
risks resulting from Neoprene Production source category emissions 
greater than 100-in-1 million.
4. Neoprene Production Whole-Facility Demographics
    We also evaluated the whole-facility post-control risks at the 
neoprene production facility. The whole-facility post-control risks 
include all known sources of HAP emissions at the neoprene production 
facility, not just those from neoprene production processes. This 
whole-facility demographic analysis provides a more complete picture of 
the remaining risks at the facility after implementation of the 
controls required by this final action and the populations exposed to 
emissions resulting from them. The post-control whole-facility 
emissions at the neoprene production facility are a combination of the 
remaining SOCMI source category risk and Neoprene Production source 
category risk at this facility. Based on whole-facility emissions, 
there are a total of about 29,000 people living within 5 km (~3.1 
miles) with risks greater than or equal to 1-in-1 million after 
controls, which is unchanged from the baseline. There are 87,000 people 
within 50 km of the neoprene facility with post-control whole-facility 
risks greater than or equal to 1-in-1 million, which is a 90 percent 
reduction of the 891,000 people in the

[[Page 43049]]

baseline. The population within 5 km with post-control whole-facility 
risks of greater than or equal to 1-in-1 million is 56 percent Black, 
and 23 percent are below the poverty level. Based on whole-facility 
emissions there are a total of about 3,000 people remaining after 
controls living within 5 km and 50 km of the neoprene facility with 
risks greater than or equal to 50-in-1 million (a reduction of 82 
percent from the baseline of 16,000 people). This population is 81 
percent Black and 30 percent below the poverty level. Based on whole-
facility emissions, about 300 people with risks greater than 100-in-1 
million remain after controls are implemented living within 5 km and 50 
km of the neoprene production facility (a reduction of 86 percent from 
the baseline of 2,300 people). This population is 99 percent Black, and 
33 percent are below the poverty level. We note that as further 
discussed in section IV.B of this preamble, the EPA is finalizing a 
secondary fenceline action level of 0.3 [micro]g/m\3\ for chloroprene 
for the whole-facility. As such, we believe once fenceline monitoring 
is fully implemented, that whole-facility post-control risks will be 
reduced to at or below 100-in-1 million and that 0 people (rather than 
the approximate 300 people as shown in this analysis) will have 
lifetime cancer risks greater than 100-in-1 million post-control.
    The results of the whole-facility demographic analysis for 
populations living within 50 km are included in the document titled 
Analysis of Demographic Factors for Populations Living Near Neoprene 
Production Operations: Whole Facility Analysis--Final, which is 
available in the docket for this rulemaking.
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5. P&R I and P&R II Source Categories Demographics
    As stated above, for the P&R I and P&R II NESHAP, other than the 
Neoprene Production source category within the P&R I NESHAP, we have 
not conducted a risk analysis for this final action. Therefore, to 
examine the potential for any environmental justice concerns that might 
be associated with P&R I (excluding neoprene) or P&R II facilities, we 
performed a proximity demographic analysis, which is an assessment of 
individual demographic groups of the populations living within 5 km 
(~3.1 miles) and 50 km (~31 miles) of the facilities. The EPA then 
compared the data from this analysis to the national average for each 
of the demographic groups. In this preamble, we focus on the proximity 
results for the populations living within 5 km (~3.1 miles) of the 
facilities. The results of the proximity analysis for populations 
living within 50 km are included in the document titled Analysis of 
Demographic Factors for Populations Living Near Polymers and Resins I 
and Polymer and Resins II Facilities (see Docket Item No. EPA-HQ-OAR-
2022-0730-0060).
    The results show that for populations within 5 km of the 18 P&R I 
facilities (5 in Louisiana, 6 in Texas, 2 in Kentucky, one each in 
Georgia, Minnesota, Mississippi, Ohio, Michigan), the following 
demographic groups were above the national average: Black individuals 
(37 percent versus 12 percent nationally), Hispanic/Latino individuals 
(24 percent versus 19 percent nationally), people living below the 
poverty level (24 percent versus 13 percent nationally), people over 
the age of 25 without a high school diploma (21 percent versus 12 
percent nationally), and linguistically isolated households (7 percent 
versus 5 percent nationally).
    The results show that for populations within 5 km of the 5 P&R II 
facilities (2 in Texas, one each in Alabama, Arkansas, Oregon), the 
following demographic groups were above the national average: American 
Indian or Alaska Native individuals (0.9 percent versus 0.7 percent 
nationally), Hispanic/Latino individuals (27 percent versus 19 percent 
nationally), and people over the age of 25 without a high school 
diploma (13 percent versus 12 percent nationally).
    A summary of the proximity demographic assessment performed is 
included as Table 15 of this preamble. The methodology and the results 
of the demographic analysis are presented in the document titled 
Analysis of Demographic Factors for Populations Living Near Polymers 
and Resins I and Polymer and Resins II Facilities (see Docket Item No. 
EPA-HQ-OAR-2022-0730-0060).

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6. Proximity Demographics Analysis for NSPS Subpart VVb
    In addition, to provide information for the public's understanding, 
the Agency conducted an analysis of the impacts of the final NSPS 
subpart VVb on communities with environmental justice concerns. The 
final NSPS subpart VVb covers VOC emissions from certain equipment 
leaks in the SOCMI from sources that are constructed, reconstructed, or 
modified after April 25, 2023.
    The locations of the new, modified, and reconstructed sources that 
will become subject to NSPS subpart VVb are not known. Therefore, to 
provide information on the potential for any environmental justice 
issues that might be associated with the final NSPS subpart VVb, we 
performed a proximity demographic analysis for 575 existing facilities 
that are currently subject to NSPS subparts VV or VVa. These

[[Page 43055]]

represent facilities that might modify or reconstruct in the future and 
become subject to the NSPS subpart VVb requirements. This proximity 
demographic analysis characterized the individual demographic groups of 
the populations living within 5 km and within 50 km (~31 miles) of the 
existing facilities. The EPA then compared the data from this analysis 
to the national average for each of the demographic groups.
    The proximity demographic analysis shows that, within 5 km of the 
facilities, the percent of the population that is Black is double the 
national average (24 percent versus 12 percent) (Table 16 of this 
preamble). The percent of people within 5 km living below the poverty 
level is significantly higher than the national average (20 percent 
versus 13 percent). The percent of people living within 5 km that are 
over 25 without a high school diploma is also higher than the national 
average (17 percent versus 12 percent). The proximity demographics 
analysis shows that within 50 km of the facilities, the percent of the 
population that is Black is above the national average (15 percent 
versus 12 percent). At 50 km, the remaining percentages for the 
demographics are similar to or below the national average.

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    The methodology and the results (including facility-specific 
results) of the demographic analysis are presented in the document 
titled Analysis of Demographic Factors for Populations Living Near 
Existing Facilities Subject to NSPS Subparts VV or VVa (see Docket Item 
No. EPA-HQ-OAR-2022-0730-0058).
7. Proximity Demographics Analysis for NSPS Subparts IIIa, NNNa, and 
RRRa
    The final NSPS subparts IIIa, NNNa, and RRRa cover VOC emissions 
from certain process vents in the SOCMI from sources that are 
constructed, reconstructed, or modified after April 25, 2023.
    The locations of the new, modified, and reconstructed sources that 
will become subject to NSPS subparts IIIa, NNNa, and RRRa are not 
known. Therefore, to assess the potential for any environmental justice 
issues that might be associated with the final subparts, we performed a 
proximity demographic analysis for 266 existing facilities that are 
currently subject to NSPS subpart III, NNN, or RRR. These facilities 
represent facilities that might modify or

[[Page 43057]]

reconstruct in the future and thus become subject to the final NSPS 
requirements. This proximity demographic analysis characterized the 
individual demographic groups of the populations living within 5 km 
(~3.1 miles) and within 50 km (~31 miles) of the existing facilities. 
The EPA then compared the data from this analysis to the national 
average for each of the demographic groups.
    The proximity demographic analysis shows that, within 5 km of the 
facilities, the percent of the population that is Black is almost 
double the national average (23 percent versus 12 percent) (Table 17 of 
this preamble). In addition, the percentage of the population within 5 
km of the facilities that is Hispanic or Latino is also above the 
national average (23 percent versus 19 percent). The percentage of 
people within 5 km living below the poverty level is significantly 
higher than the national average (20 percent versus 13 percent). The 
percentage of people living within 5 km that are over 25 without a high 
school diploma is also higher than the national average (17 percent 
versus 12 percent). The proximity demographics analysis also shows that 
within 50 km of the facilities, the percentage of the population that 
is Black is above the national average (18 percent versus 12 percent). 
At 50 km, the remaining percentages for the demographics are similar to 
or below the national average.
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    The methodology and the results (including facility-specific 
results) of the demographic analysis are presented in the document 
titled Analysis of Demographic Factors for Populations Living Near 
Existing Facilities Subject to NSPS Subparts III, NNN, or RRR (see 
Docket Item No. EPA-HQ-OAR-2022-0730-0059).
G. Children's Environmental Health
    This action finalizes standards to address risk from, among other 
HAP, EtO and chloroprene. In addition, the EPA's Policy on Children's 
Health \72\ also applies to this action. Accordingly, we evaluated the 
environmental health or safety effects of EtO and chloroprene emissions 
and exposures on children.
---------------------------------------------------------------------------

    \72\ Children's Health Policy Available at: https://www.epa.gov/children/childrens-health-policy-and-plan.
---------------------------------------------------------------------------

    Because EtO and chloroprene are mutagenic (i.e., it can damage 
DNA), children are expected to be more susceptible to their harmful 
effects. To take this into account, as part of the risk assessments in 
support of this rulemaking, the EPA followed its

[[Page 43059]]

guidelines \73\ and applied age-dependent adjustment factors (ADAFs) 
for childhood exposures (from birth up to 16 years of age). It should 
be noted that, because EtO and chloroprene are mutagenic, emission 
reductions finalized in this action will be particularly beneficial to 
children. The results of this evaluation are contained in section IV.A 
of this preamble and further documented in the risk reports, Residual 
Risk Assessment for the SOCMI Source Category in Support of the 2024 
Risk and Technology Review Final Rule and Residual Risk Assessment for 
the Polymers & Resins I Neoprene Production Source Category in Support 
of the 2024 Risk and Technology Review Final Rule, which are available 
in the docket.
---------------------------------------------------------------------------

    \73\ U.S. EPA. 2005. Supplemental Guidance for Assessing 
Susceptibility from Early-Life Exposure to Carcinogens. U.S. 
Environmental Protection Agency, Washington, DC, EPA/630/R-03/003F. 
https://www.epa.gov/sites/default/files/2013-09/documents/childrens_supplement_final.pdf.
---------------------------------------------------------------------------

VI. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 14094: Modernizing Regulatory Review

    This action is a ``significant regulatory action'' as defined under 
section 3(f)(1) of Executive Order 12866, as amended by Executive Order 
14094. Accordingly, the EPA submitted this action to the Office of 
Management and Budget (OMB) for Executive Order 12866 review. 
Documentation of any changes made in response to the Executive Order 
12866 review is available in the docket. The EPA prepared an economic 
analysis of the potential impacts associated with this action. This 
analysis, titled Regulatory Impact Analysis for the Final New Source 
Performance Standards for the Synthetic Organic Chemical Manufacturing 
Industry and National Emission Standards for Hazardous Air Pollutants 
for the Synthetic Organic Chemical Manufacturing Industry and Group I & 
II Polymers and Resins Industry (EPA-452/R-24-001), is also available 
in the docket. Table 18 of this preamble summarizes the PV and EAV of 
total costs and benefits for the final action.
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B. Paperwork Reduction Act (PRA)

1. HON
    The information collection activities in this rule have been 
submitted for approval to OMB under the PRA. The information collection 
request (ICR) document that the EPA prepared has been assigned EPA ICR 
number 2753.02. You can find a copy of the ICR in the docket for this 
rule, and it is briefly summarized here. The information collection 
requirements are not enforceable until OMB approves them.
    The EPA is finalizing amendments to the HON that revise provisions 
pertaining to emissions from flares, PRDs, process vents, storage 
vessels, pressure vessels, storage vessel degassing, heat exchange 
systems, maintenance vents, wastewater, and equipment leaks. The EPA is 
also finalizing additional requirements pertaining to EtO emissions 
from process vents, storage vessels, heat exchange systems, equipment 
leaks, and wastewater; and dioxins and furans emissions from process 
vents. In addition, the EPA is finalizing amendments to the HON that 
revise provisions pertaining to emissions during periods of SSM, add 
requirements for electronic reporting of periodic reports and 
performance test results, fenceline monitoring, carbon adsorbers, and 
bypass monitoring, and make other minor clarifications and corrections. 
This information will be collected to assure compliance with the HON.
    Respondents/affected entities: Owners or operators of HON 
facilities.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subparts F, G, H, and I).
    Estimated number of respondents: 209 (assumes two new respondents 
over the next 3 years).
    Frequency of response: Initially, quarterly, semiannually, and 
annually.
    Total estimated burden: average annual recordkeeping and reporting 
burden is 83,500 hours (per year) to comply with the final amendments 
in HON. Burden is defined at 5 CFR 1320.3(b).
    Total estimated cost: average annual cost is $66,000,000 (per year) 
which includes $57,500,000 annualized capital and operations and 
maintenance costs, to comply with the final amendments in HON.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities in this final rule.
2. P&R I NESHAP
    The information collection activities in this rule have been 
submitted for approval to OMB under the PRA. The ICR document that the 
EPA prepared has been assigned EPA ICR number 2410.07. You can find a 
copy of the ICR in the docket for this rule, and it is briefly 
summarized here. The information collection requirements are not 
enforceable until OMB approves them.
    The EPA is finalizing amendments to the P&R I NESHAP that revise 
provisions pertaining to emissions from flares, PRDs, continuous 
process vents, batch process vents, storage vessels, pressure vessels, 
storage vessel degassing, heat exchange systems, maintenance vents, 
wastewater, and equipment leaks. The EPA is also finalizing 
requirements pertaining to: chloroprene emissions from process vents, 
storage vessels, and wastewater; and dioxins and furans emissions from 
continuous process vents and batch process vents. In addition, the EPA 
is finalizing amendments to the P&R I NESHAP that revise provisions 
pertaining to emissions during periods of SSM, add requirements for 
electronic reporting of periodic reports and performance test results, 
fenceline monitoring, carbon adsorbers, and bypass monitoring, and make 
other minor clarifications and corrections. This information will be 
collected to assure compliance with the P&R I NESHAP.
    Respondents/affected entities: Owners or operators of P&R I 
facilities.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart U).
    Estimated number of respondents: 19 (assumes no new respondents 
over the next 3 years).
    Frequency of response: Initially, quarterly, semiannually, and 
annually.
    Total estimated burden: average annual recordkeeping and reporting 
burden is 8,126 hours (per year) to comply with the final amendments in 
the P&R I NESHAP. Burden is defined at 5 CFR 1320.3(b).
    Total estimated cost: average annual cost is $3,200,000 (per year) 
which includes $2,370,000 annualized capital and operations and 
maintenance costs, to comply with the final amendments in the P&R I 
NESHAP.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities in this final rule.
3. P&R II NESHAP
    The information collection activities in this rule have been 
submitted for approval to OMB under the PRA. The ICR document that the 
EPA prepared has been assigned EPA ICR number 1681.12. The OMB Control 
Number is 2060-0290. You can find a copy of the ICR in the docket for 
this rule, and it is briefly summarized here. The information 
collection requirements are not enforceable until OMB approves them.
    The EPA is finalizing amendments to the P&R II NESHAP to add 
requirements pertaining to: heat exchange systems, PRDs, dioxins and 
furans emissions from process vents, and maintenance vents. In 
addition, the EPA is finalizing amendments to the P&R II NESHAP that 
revise provisions pertaining to emissions during periods of SSM, add 
requirements for electronic reporting of periodic reports and 
performance test results, and make other minor clarifications and 
corrections. This information will be collected to assure compliance 
with the P&R II NESHAP.
    Respondents/affected entities: Owners or operators of P&R II 
facilities.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart W).
    Estimated number of respondents: 5 (assumes no new respondents over 
the next 3 years).
    Frequency of response: Initially, semiannually, and annually.
    Total estimated burden: average annual recordkeeping and reporting 
burden is 202 hours (per year) to comply with the final amendments in 
the P&R II NESHAP. Burden is defined at 5 CFR 1320.3(b).
    Total estimated cost: average annual cost is $1,780,000 (per year) 
which includes $1,760,000 annualized capital and operations and 
maintenance costs, to comply with the final amendments in the P&R II 
NESHAP.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control

[[Page 43062]]

numbers for the EPA's regulations in 40 CFR are listed in 40 CFR part 
9. When OMB approves this ICR, the Agency will announce that approval 
in the Federal Register and publish a technical amendment to 40 CFR 
part 9 to display the OMB control number for the approved information 
collection activities in this final rule.
4. NSPS Subparts VV, VVa, III, NNN, and RRR
    This action does not impose any new information collection burden 
under the PRA for NSPS subparts VV, VVa, III, NNN, and RRR. OMB has 
previously approved the information collection activities contained in 
the existing regulations and has assigned OMB Control number 2060-0443 
for 40 CFR part 60 subparts VV, VVa, III, NNN, and RRR (this one OMB 
Control number is for the Consolidated Federal Air Rule in 40 CFR part 
65 which presents the burden for complying with 40 CFR part 65, but 
also presents the burden for facilities complying with each individual 
subpart). This action is believed to result in no changes to the 
information collection requirements of these NSPS, so that the 
information collection estimate of project cost and hour burden from 
these NSPS have not been revised.
5. NSPS Subpart VVb
    The information collection activities in this rule have been 
submitted for approval to OMB under the PRA. The ICR document that the 
EPA prepared has been assigned EPA ICR number 2755.02. You can find a 
copy of the ICR in the docket for this rule, and it is briefly 
summarized here. The information collection requirements are not 
enforceable until OMB approves them.
    The EPA is finalizing in a new NSPS subpart VVb the same 
requirements in NSPS subpart VVa plus requiring that all gas/vapor and 
light liquid valves be monitored monthly at a leak definition of 100 
ppm and all connectors be monitored once every 12 months at a leak 
definition of 500 ppm. In addition, the EPA is finalizing the removal 
of SSM provisions (the standards apply at all times), additional 
requirements for electronic reporting of periodic reports, and other 
minor clarifications and corrections. This information will be 
collected to assure compliance with the NSPS subpart VVb.
    Respondents/affected entities: Owners or operators of certain 
equipment leaks in the SOCMI.
    Respondent's obligation to respond: Mandatory (40 CFR part 60, 
subpart VVb).
    Estimated number of respondents: 36 (assumes 36 new respondents 
over the next 3 years).
    Frequency of response: Initially, occasionally, and annually.
    Total estimated burden: average annual recordkeeping and reporting 
burden is 5,414 hours (per year) to comply with all of the requirements 
in the NSPS. Burden is defined at 5 CFR 1320.3(b).
    Total estimated cost: average annual cost is $3,600,000 (per year) 
which includes $3,050,000 annualized capital and operations and 
maintenance costs, to comply with all of the requirements in the NSPS.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities in this final rule.
6. NSPS Subpart IIIa
    The information collection activities in this rule have been 
submitted for approval to OMB under the PRA. The ICR document that the 
EPA prepared has been assigned EPA ICR number 2756.02. You can find a 
copy of the ICR in the docket for this rule, and it is briefly 
summarized here. The information collection requirements are not 
enforceable until OMB approves them.
    The EPA is finalizing requirements for new, modified, or 
reconstructed sources as follows: require owners and operators reduce 
emissions of TOC (minus methane and ethane) from all vent streams of an 
affected facility (and not including the alternative of maintaining a 
TRE index value greater than 1 without the use of a control device); 
require standards apply at all times (including during SSM periods); 
revise monitoring requirements for flares; add maintenance vent 
requirements; revise requirements for adsorber monitoring; exclude the 
relief valve discharge exemption such that any relief valve discharge 
to the atmosphere of a vent stream is a violation of the emissions 
standard; and prohibit an owner or operator from bypassing the control 
device at any time, and to report any such violation. This information 
will be collected to assure compliance with the NSPS subpart IIIa.
    Respondents/affected entities: Owners or operators of air oxidation 
unit processes in the SOCMI.
    Respondent's obligation to respond: Mandatory (40 CFR part 60, 
subpart IIIa).
    Estimated number of respondents: 6 (assumes 6 new respondents over 
the next 3 years).
    Frequency of response: Initially, semiannually, and annually.
    Total estimated burden: average annual recordkeeping and reporting 
burden is 275 hours (per year) to comply with all of the requirements 
in NSPS subpart IIIa. Burden is defined at 5 CFR 1320.3(b).
    Total estimated cost: average annual cost is $4,280,000 (per year) 
which includes $4,250,000 annualized capital and operations and 
maintenance costs, to comply with all of the requirements in NSPS 
subpart IIIa.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities in this final rule.
7. NSPS Subpart NNNa
    The information collection activities in this rule have been 
submitted for approval to OMB under the PRA. The ICR document that the 
EPA prepared has been assigned EPA ICR number 2757.02. You can find a 
copy of the ICR in the docket for this rule, and it is briefly 
summarized here. The information collection requirements are not 
enforceable until OMB approves them.
    The EPA is finalizing requirements for new, modified, or 
reconstructed sources as follows: require owners and operators reduce 
emissions of TOC (minus methane and ethane) from all vent streams of an 
affected facility (and not including the alternative of maintaining a 
TRE index value greater than 1 without the use of a control device); 
require the standards apply at all times (including during SSM 
periods); revise monitoring requirements for flares; add maintenance 
vent requirements; revise requirements for adsorber monitoring; exclude 
the relief valve discharge exemption such that any relief valve 
discharge to the atmosphere of a vent stream is a violation of the 
emissions standard; and prohibit an owner or

[[Page 43063]]

operator from bypassing the control device at any time, and to report 
any such violation. This information will be collected to assure 
compliance with the NSPS subpart NNNa.
    Respondents/affected entities: Owners or operators of distillation 
operations in the SOCMI.
    Respondent's obligation to respond: Mandatory (40 CFR part 60, 
subpart NNNa).
    Estimated number of respondents: 7 (assumes 7 new respondents over 
the next 3 years).
    Frequency of response: Initially, semiannually, and annually.
    Total estimated burden: average annual recordkeeping and reporting 
burden is 320 hours (per year) to comply with all of the requirements 
in NSPS subpart NNNa. Burden is defined at 5 CFR 1320.3(b).
    Total estimated cost: average annual cost is $4,990,000 (per year) 
which includes $4,960,000 annualized capital and operations and 
maintenance costs, to comply with all of the requirements in NSPS 
subpart NNNa.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities in this final rule.
8. NSPS Subpart RRRa
    The information collection activities in this rule have been 
submitted for approval to OMB under the PRA. The ICR document that the 
EPA prepared has been assigned EPA ICR number 2759.02. You can find a 
copy of the ICR in the docket for this rule, and it is briefly 
summarized here. The information collection requirements are not 
enforceable until OMB approves them.
    The EPA is finalizing requirements for new, modified, or 
reconstructed sources as follows: require owners and operators reduce 
emissions of TOC (minus methane and ethane) from all vent streams of an 
affected facility (and not including the alternative of maintaining a 
TRE index value greater than 1 without the use of a control device); 
require the standards apply at all times (including during SSM 
periods); revise monitoring requirements for flares; add maintenance 
vent requirements; revise requirements for adsorber monitoring; exclude 
the relief valve discharge exemption such that any relief valve 
discharge to the atmosphere of a vent stream is a violation of the 
emissions standard; and prohibit an owner or operator from bypassing 
the control device at any time, and to report any such violation. This 
information will be collected to assure compliance with the NSPS 
subpart RRRa.
    Respondents/affected entities: Owners or operators of reactor 
processes in the SOCMI.
    Respondent's obligation to respond: Mandatory (40 CFR part 60, 
subpart RRRa).
    Estimated number of respondents: 6 (assumes 6 new respondents over 
the next 3 years).
    Frequency of response: Initially, semiannually, and annually.
    Total estimated burden: average annual recordkeeping and reporting 
burden is 275 hours (per year) to comply with all of the requirements 
in NSPS subpart RRRa. Burden is defined at 5 CFR 1320.3(b).
    Total estimated cost: average annual cost is $4,280,000 (per year) 
which includes $4,250,000 annualized capital and operations and 
maintenance costs, to comply with all of the requirements in NSPS 
subpart RRRa.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities in this final rule.

C. Regulatory Flexibility Act (RFA)

    I certify that each of the final rules in this action will not have 
a significant economic impact on a substantial number of small entities 
under the RFA. The small entities subject to the requirements of this 
action are small businesses. For the final amendments to the HON, the 
Agency has determined that all small entities affected by this action, 
estimated to be 9, may experience an average impact of costs being less 
than 0.5 percent of revenues, not including product recovery, or about 
0.43 percent, including product recovery from compliance. Two of these 
nine entities experienced costs above one percent of revenues, neither 
had costs exceeding three percent of revenues and represent a small 
total number of impacted entities. For the final amendments to the P&R 
I NESHAP, one small entity is impacted and its impact is costs less 
than 0.5 percent of revenues. For the final amendments to the P&R II 
NESHAP, no small entities are impacted. Details of the analysis for 
each final rule including the NSPS that are included in this final 
action are presented in the RIA for this action, which is found in the 
docket.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more (adjusted for inflation) as described in UMRA, 2 U.S.C. 1531-1538, 
and does not significantly or uniquely affect small governments. The 
costs involved in this action are estimated not to exceed $100 million 
or more (adjusted for inflation) in any one year.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications as specified in 
Executive Order 13175. None of the facilities that have been identified 
as being affected by this action are owned or operated by tribal 
governments or located within tribal lands. Thus, Executive Order 13175 
does not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    Executive Order 13045 directs federal agencies to include an 
evaluation of the health and safety effects of the planned regulation 
on children in federal health and safety standards and explain why the 
regulation is preferable to potentially effective and reasonably 
feasible alternatives. This action is subject to Executive Order 13045 
because it is a significant regulatory action under section 3(f)(1) of 
Executive Order 12866, and the EPA believes that the environmental 
health or safety risk addressed by this action may have a 
disproportionate effect on children. This is because EtO and 
chloroprene, which are HAP emitted by sources subject to this action, 
are mutagenic (i.e., it can damage DNA), and children are presented 
with higher risks based on the

[[Page 43064]]

EPA's ADAFs for these HAP. Accordingly, we have evaluated the 
environmental health or safety effects of EtO and chloroprene emissions 
on children.
    The protection offered by these standards to reduce emissions of 
EtO and chloroprene accounts for childhood exposures by applying ADAFs 
to account for greater susceptibility of children to these HAP. The 
results of this evaluation are contained in section IV.A of this 
preamble and further documented in the risk reports, Residual Risk 
Assessment for the SOCMI Source Category in Support of the 2024 Risk 
and Technology Review Final Rule and Residual Risk Assessment for the 
Polymers & Resins I Neoprene Production Source Category in Support of 
the 2024 Risk and Technology Review Final Rule, which are available in 
the docket. This action is preferred over other regulatory options 
because a residual risk assessment was performed and options were 
assessed and finalized to reduce emissions of EtO and chloroprene, 
which will be extremely beneficial to children. Furthermore, EPA's 
Policy on Children's Health also applies to this action. Information on 
how the Policy was applied is available under ``Children's 
Environmental Health'' in the Supplementary Information section of this 
preamble.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy. The EPA expects this final action would 
not reduce crude oil supply, fuel production, coal production, natural 
gas production, or electricity production. We estimate that this final 
action would have minimal impact on the amount of imports or exports of 
crude oils, condensates, or other organic liquids used in the energy 
supply industries. Given the minimal impacts on energy supply, 
distribution, and use as a whole nationally, no significant adverse 
energy effects are expected to occur. For more information on these 
estimates of energy effects, please refer to the economic impact 
analysis contained in the RIA for this final rulemaking.

I. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR 
Part 51

    This action involves technical standards. As discussed in the 
proposal preamble (88 FR 25080, April 25, 2023), the EPA conducted 
searches for the HON and the P&R I and P&R II NESHAP through the 
Enhanced National Standards Systems Network Database managed by the 
American National Standards Institute (ANSI). We also conducted a 
review of voluntary consensus standards (VCS) organizations and 
accessed and searched their databases. We conducted searches for EPA 
Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 3B, 4, 18, 21, 22, 25A, 25D, 26, 
26A, 27 of 40 CFR part 60, Appendix A, 301, 305, 316 and 320 of 40 CFR 
part 63, Appendix A, 624, 625, 1624, and 1625 of 40 CFR part 136 
Appendix A, 624.1 of 40 CFR part 163, Appendix A. During the EPA's VCS 
search, if the title or abstract (if provided) of the VCS described 
technical sampling and analytical procedures that are similar to the 
EPA's reference method, the EPA ordered a copy of the standard and 
reviewed it as a potential equivalent method. We reviewed all potential 
standards to determine the practicality of the VCS for this rule. This 
review requires significant method validation data that meet the 
requirements of EPA Method 301 for accepting alternative methods or 
scientific, engineering, and policy equivalence to procedures in the 
EPA referenced methods. The EPA may reconsider determinations of 
impracticality when additional information is available for particular 
VCS. No applicable voluntary consensus standards were identified for 
EPA Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 21, 22, 25D, 27, 305, 316, 
624, 624.1, 625, 1624 and 1625.
    The EPA incorporates by reference VCS ANSI/ASME PTC 19.10-1981--
Part 10, ``Flue and Exhaust Gas Analyses'' as an acceptable alternative 
to EPA Method 3B (referenced in NSPS subparts IIIa, NNNa, RRR, and 
RRRa, and NESHAP subpart G) for the manual procedures only and not the 
instrumental procedures. This method is used to quantitatively 
determine the gaseous constituents of exhausts including oxygen, 
CO2, carbon monoxide, nitrogen, sulfur dioxide, sulfur 
trioxide, nitric oxide, nitrogen dioxide, hydrogen sulfide, and 
hydrocarbons. The ANSI/ASME PTC 19.10-1981--Part 10 method incorporates 
both manual and instrumental methodologies for the determination of 
oxygen content. The manual method segment of the oxygen determination 
is performed through the absorption of oxygen. This method is available 
at the ANSI, 1899 L Street NW, 11th Floor, Washington, DC 20036 and the 
American Society of Mechanical Engineers (ASME), Three Park Avenue, New 
York, NY 10016-5990; telephone number: 1-800-843-5990; and email 
address: [email protected]. See https://wwww.ansi.org and https://www.asme.org. The standard is available to everyone at a cost 
determined by ANSI/ASME ($96). ANSI/ASME also offer memberships or 
subscriptions for reduced costs. The cost of obtaining these methods is 
not a significant financial burden, making the methods reasonably 
available.
    The EPA incorporates by reference VCS ASTM D6420-18, ``Standard 
Test Method for Determination of Gaseous Organic Compounds by Direct 
Interface Gas Chromatography-Mass Spectrometry'' as an acceptable 
alternative to EPA Method 18 (referenced in NSPS subparts VV, VVa, VVb, 
III, IIIa, NNN, NNNa, RRR, and RRRa, and NESHAP subparts F, G, H, I, U, 
and W) with the following caveats. This ASTM procedure uses a direct 
interface gas chromatograph/mass spectrometer to identify and quantify 
VOC and has been approved by the EPA as an alternative to EPA Method 18 
only when the target compounds are all known and the target compounds 
are all listed in ASTM D6420 as measurable. ASTM D6420-18 should not be 
used for methane and ethane because the atomic mass is less than 35; 
and ASTM D6420 should never be specified as a total VOC method. The 
ASTM D6420-18 test method employs a direct interface gas chromatograph/
mass spectrometer to measure 36 VOC. The test method provides onsite 
analysis of extracted, unconditioned, and unsaturated (at the 
instrument) gas samples from stationary sources.
    The EPA incorporates by reference VCS ASTM D6348-12 (Reapproved 
2020), ``Standard Test Method for Determination of Gaseous Compounds by 
Extractive Direct Interface Fourier Transform Infrared (FTIR) 
Spectroscopy'' as an acceptable alternative to EPA Method 320 
(referenced in NESHAP subparts F and U) with caveats requiring 
inclusion of selected annexes to the standard as mandatory. This ASTM 
procedure uses an extractive sampling system that routes stationary 
source effluent to an FTIR spectrometer for the identification and 
quantification of gaseous compounds. We note that we proposed VCS ASTM 
D6348-12e1 as an alternative to EPA Method 320; however, since 
proposal, a newer version of the method (VCS ASTM D6348-12 (Reapproved 
2020)) is now available and we have determined it to be equivalent to 
EPA Method 320 with caveats. The VCS ASTM D6348-12

[[Page 43065]]

(Reapproved 2020) method is an extractive FTIR Spectroscopy-based field 
test method and is used to quantify gas phase concentrations of 
multiple target compounds in emission streams from stationary sources. 
When using ASTM D6348-12 (Reapproved 2020), the following conditions 
must be met: (1) Annexes Al through A8 to ASTM D6348-12 (Reapproved 
2020) are mandatory; and (2) in ASTM D6348-12 (Reapproved 2020) Annex 
A5 (Analyte Spiking Technique), the percent (%) R must be determined 
for each target analyte (Equation A5.5). In order for the test data to 
be acceptable for a compound, %R must be 70% >= R <= 130%. If the %R 
value does not meet this criterion for a target compound, the test data 
is not acceptable for that compound and the test must be repeated for 
that analyte (i.e., the sampling and/or analytical procedure should be 
adjusted before a retest). The %R value for each compound must be 
reported in the test report, and all field measurements must be 
corrected with the calculated %R value for that compound by using the 
following equation:

Reported Results = ((Measured Concentration in Stack))/(%R) x 100.

    The EPA is also incorporating by reference Quality Assurance 
Handbook for Air Pollution Measurement Systems, Volume IV: 
Meteorological Measurements, Version 2.0 (Final), March 2008 (EPA-454/
B-08-002). The Quality Assurance Handbook for Air Pollution Measurement 
Systems; Volume IV: Meteorological Measurements is an EPA developed 
guidance manual for the installation, operation, maintenance and 
calibration of meteorological systems including the wind speed and 
direction using anemometers, temperature using thermistors, and 
atmospheric pressure using aneroid barometers, as well as the 
calculations for wind vector data for on-site meteorological 
measurements. This VCS may be obtained from the EPA's National Service 
Center for Environmental Publications (www.epa.gov/nscep).
    The two ASTM methods (ASTM D6420-18 and ASTM D6348-12 (Reapproved 
2020)) are available at ASTM International, 1850 M Street NW, Suite 
1030, Washington, DC 20036; telephone number: 1-610-832-9500. See 
https://www.astm.org/. These standards are available to everyone at a 
cost determined by the ASTM ($57 and $76, respectively). The ASTM also 
offers memberships or subscriptions that allow unlimited access to 
their methods. The cost of obtaining these methods is not a significant 
financial burden, making the methods reasonably available to 
stakeholders.
    While the EPA identified 13 other VCS as being potentially 
applicable, the Agency decided not to use them because these methods 
are impractical as alternatives because of the lack of equivalency, 
documentation, validation date, and other important technical and 
policy considerations. The search and review results have been 
documented and are in the memorandum, Voluntary Consensus Standard 
Results for National Emission Standards for Hazardous Air Pollutants 
From the Synthetic Organic Chemical Manufacturing Industry (see Docket 
Item No. EPA-HQ-OAR-2022-0730-0008).
    Under 40 CFR 63.7(f) and 40 CFR 63.8(f), subpart A--General 
Provisions, a source may apply to the EPA for permission to use 
alternative test methods or alternative monitoring requirements in 
place of any required testing methods, performance specifications, or 
procedures in the final rule or any amendments.
    Also, although not considered a VCS, the EPA incorporates by 
reference, ``Purge-And-Trap For Aqueous Samples'' (SW-846-5030B), 
``Volatile, Nonpurgeable, Water-Soluble Compounds by Azeotropic 
Distillation'' (SW-846-5031), and ``Volatile Organic Compounds by Gas 
Chromatography/Mass Spectrometry (GC/MS)'' (SW-846-8260D) into 40 CFR 
63.109(b)(1), (c)(1), (d), and (e) (for HON) and 40 CFR 63.510(b)(1) 
and (c) (for the P&R I NESHAP); and ``Air Stripping Method (Modified El 
Paso Method) for Determination of Volatile Organic Compound Emissions 
from Water Sources,'' into 40 CFR 63.104(g)(3)(i) and (ii), and 40 CFR 
63.104(f)(3)(iv)(D)(1). Method SW-846-5030B can be used as a purge-and-
trap procedure for the analysis of volatile organic compounds in 
aqueous samples and water miscible liquid samples. Method SW-846-5031 
can be used for separation of nonpurgeable, water-soluble, and volatile 
organic compounds in aqueous samples or leachates from solid matrices 
using azeotropic distillation. Method SW-846-8260D can be used to 
determine VOCs in a variety of solid waste matrices and is applicable 
to nearly all types of samples, regardless of water content. The 
Modified El Paso Method utilizes dynamic or flow-through system for air 
stripping a sample of water and analyzing the resultant off-gases for 
VOCs using a common flame ionization detector (FID) analyzer. Each of 
these methods is used to identify organic HAP in water; however, SW-
846-5031, SW-846-8260D, and SW-846-5030B use water sampling techniques 
and the Modified El Paso Method uses an air stripping sampling 
technique. The SW-846 methods are reasonably available from the EPA at 
https://www.epa.gov/hw-sw846 while the Modified El Paso Method is 
reasonably available from TCEQ at https://www.tceq.texas.gov/assets/public/compliance/field_ops/guidance/samplingappp.pdf.
    In addition, because we are moving all HON definitions from NESHAP 
subparts G and H (i.e., 40 CFR 63.111 and 40 CFR 63.161, respectively) 
into the definition section of NESHAP subpart F (i.e., 40 CFR 63.101), 
we are incorporating by reference, API Manual of Petroleum Measurement 
Specifications (MPMS) Chapter 19.2 (API MPMS 19.2), ``Evaporative Loss 
From Floating-Roof Tanks,'' Fourth Edition, August 2020 and ``Standard 
Test Method for Vapor Pressure-Temperature Relationship and Initial 
Decomposition Temperature of Liquids by Isoteniscope'' (ASTM D2879-23) 
into 40 CFR 63.101 (for HON). The API method (API MPMS 19.2) \74\ 
contains methodologies for estimating the total evaporative losses of 
hydrocarbons from various types of floating-roof tanks. The ASTM method 
(ASTM D2879-23) addresses the determination of the vapor pressure of 
one or more organic components in a gas stream. In addition, the EPA is 
adding new NSPS subpart VVb to part 60 and is allowing the use of:
---------------------------------------------------------------------------

    \74\ API MPMS 19.2 is a replacement for API publication 2517, 
which was previously referenced in the HON.
---------------------------------------------------------------------------

    ASTM D240-19, Standard Test Method for Heat of Combustion of Liquid 
Hydrocarbon Fuels by Bomb Calorimeter and ASTM D4809-18, Standard Test 
Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb 
Calorimeter (Precision Method). The ASTM D240-19 method addresses the 
determination of net heat of combustion of components of liquid 
hydrocarbon fuels ranging in volatility from that of light distillates 
to that of residual fuels. The ASTM D4809-18 method is similar to that 
of ASTM D240-19, though it specifically addresses the determination of 
net heat of combustion of aviation fuels with high precision. In 
addition, ASTM D4809-18 can also be used to address the determination 
of net heat of combustion for a wide range of volatile and non-volatile 
materials. The EPA currently allows for the use of previous versions of 
these methods in NSPS

[[Page 43066]]

subparts VV and VVa for the determination of net heat of combustion of 
components in a gas stream; therefore, we are allowing the use of the 
most recent versions of these methods for this same purpose in NSPS 
subpart VVb.
    ASTM D1945-14 (Reapproved 2019), Standard Test Method for Analysis 
of Natural Gas by Gas Chromatography. This method addresses the 
determination of the concentration of a component in a gas stream. The 
EPA currently allows for the use of previous versions of this method in 
NSPS subparts VV and VVa for the determination of the concentration of 
a component in a gas stream; therefore, we are allowing the use of the 
most recent version of this method for this same purpose in NSPS 
subpart VVb.
    ASTM D2879-23, Standard Test Method for Vapor Pressure-Temperature 
Relationship and Initial Decomposition Temperature of Liquids by 
Isoteniscope. This method addresses the determination of the vapor 
pressure of one or more organic components in a gas stream. The EPA 
currently allows for the use of previous versions of this method in 
NSPS subparts VV and VVa for the determination of the vapor pressure of 
one or more organic components in a gas stream; therefore, we are 
allowing the use of the most recent version of this method for this 
same purpose in NSPS subpart VVb.
    ASTM E168-16 (Reapproved 2023), Standard Practices for General 
Techniques of Infrared Quantitative Analysis, ASTM E169-16 (Reapproved 
2022): Standard Practices for General Techniques of Ultraviolet-Visible 
Quantitative Analysis, and ASTM E260-96 (Reapproved 2019), Standard 
Practice for Packed Column Gas Chromatography. The ASTM E168-16 method 
addresses the determination of the percent VOC content in the process 
fluid that is contained in or contacts a piece of equipment using 
infrared analysis. The ASTM E169-16 is similar to ASTM E168-16, though 
it uses ultraviolet-visible spectrum analysis rather than infrared 
analysis. Lastly, ASTM E260-96 is similar to ASTM E168-16 and ASTM 
E169-16, though it uses gas chromatography rather than infrared or 
ultraviolet-visible spectrum analysis, respectively. The EPA currently 
allows for the use of previous versions of these methods in NSPS 
subparts VV and VVa for the determination of the percent VOC content in 
the process fluid that is contained in or contacts a piece of 
equipment; therefore, we are allowing the use of these most recent 
versions of these methods for this same purpose in NSPS subpart VVb.
    All of the ASTM methods that we are adding into the HON, the P&R I 
NESHAP, and NSPS subpart VVb are available at the same address and 
contact information provided earlier in this section of this preamble. 
The API method that we are adding into the HON is available at 200 
Massachusetts Avenue NW, Suite 1100, Washington, DC 20001-5571; 
telephone number: 1-202-682-8000. See https://www.apiwebstore.org/standards/19_2. These standards are available to everyone at a cost 
determined by the ASTM or API. The ASTM also offers memberships or 
subscriptions that allow unlimited access to their methods. The cost of 
obtaining these methods is not a significant financial burden, making 
the methods reasonably available to stakeholders.
    We are also finalizing amendments to 40 CFR part 60, subpart A and 
40 CFR part 63, subpart A to address incorporations by reference. We 
are amending 40 CFR 60.17 and 40 CFR 63.14 to reflect the ANSI, ASTM, 
EPA SW, and TCEQ methods incorporated by reference. We are also adding 
40 CFR 60.485(g)(5) and 40 CFR 60.485a(g)(5) to 40 CFR 60.17--
``Incorporations by Reference'' paragraph (h)(195) since they were 
mistakenly not added to 40 CFR 60.17 during the last amendment to this 
rule.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations and 
Executive Order 14096: Revitalizing Our Nation's Commitment to 
Environmental Justice for All

    The EPA believes that the human health or environmental conditions 
that exist prior to this action result in or have the potential to 
result in disproportionate and adverse human health or environmental 
effects on communities with environmental justice concerns. For the 
HON, a total of 9.3 million people live within 10 km (~6.2 miles) of 
the 195 HON facilities that were assessed for risk. The percentages of 
the population that are Black (25 percent versus 12 percent) and 
Hispanic or Latino (22 percent versus 19 percent) are higher than the 
national averages. The proportion of other demographic groups living 
within 10 km of HON facilities is similar or lower than the national 
average. For the Neoprene Production source category, a total of 29,000 
people live within 5 km of the one neoprene production facility in the 
country. The percent of the population that is Black (56 percent versus 
12 percent) is substantially higher than the national average. The 
proportion of other demographic groups living within 10 km of HON 
facilities is similar or lower than the national average. The EPA also 
conducted a risk assessment of possible cancer risks and other adverse 
health effects, and found that prior to this final rule, cancer risks 
were above acceptable levels for a number of areas in which these 
demographic groups live for the SOCMI and Neoprene Production source 
categories. See section V.F for an analysis that characterizes 
populations living in proximity of facilities and risks prior to the 
final rule.
    The EPA believes that this action is likely to reduce existing 
disproportionate and adverse effects on communities with environmental 
justice concerns. This action establishes standards for EtO emission 
sources at HON processes and chloroprene emission sources at neoprene 
production processes. This action also corrects and clarifies 
regulatory provisions related to emissions during periods of SSM, 
including removing general exemptions for periods of SSM and adding 
work practice standards for periods of SSM where appropriate, 
addressing flare combustion efficiency, and requiring fenceline 
monitoring for pollutants that drive cancer risks for HON and neoprene 
production sources. As a result of these changes, we expect zero people 
to be exposed to risk levels above 100-in-1 million due to emissions 
from each of these source categories. See section IV.A of this preamble 
for more information about the control requirements of the regulation 
and the resulting reduction in cancer risks.
    The EPA additionally identified and addressed environmental justice 
concerns by engaging in outreach activities to communities we expect to 
be impacted by chemical plants that emit EtO.\75\
---------------------------------------------------------------------------

    \75\ https://www.epa.gov/hazardous-air-pollutants-ethylene-oxide/inspector-general-follow-ethylene-oxide-0.
---------------------------------------------------------------------------

    For additional information on potential impacts, see the document 
titled Analysis of Demographic Factors for Populations Living Near 
Hazardous Organic NESHAP (HON) Operations--Final; Analysis of 
Demographic Factors for Populations Living Near Hazardous Organic 
NESHAP (HON) Operations: Whole Facility Analysis--Final; Analysis of 
Demographic Factors for Populations Living Near Neoprene Production 
Operations--Final; Analysis of Demographic Factors for Populations 
Living Near Neoprene Production Operations: Whole Facility Analysis--

[[Page 43067]]

Final, which are available in the docket for this rulemaking. Also see 
the document titled Analysis of Demographic Factors for Populations 
Living Near Polymers and Resins I and Polymer and Resins II Facilities 
(Docket Item No. EPA-HQ-OAR-2022-0730-0060).

K. Congressional Review Act (CRA)

    This action is subject to the CRA, and the EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the United States. This action meets the criteria set forth in 5 U.S.C. 
804(2).

List of Subjects

40 CFR Part 60

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Incorporation by reference, Intergovernmental 
relations, Reporting and recordkeeping requirements.

40 CFR Part 63

    Environmental protection, Air pollution control, Hazardous 
substances, Incorporation by reference, Intergovernmental relations, 
Reporting and recordkeeping requirements.

Michael S. Regan,
Administrator.

    For the reasons set out in the preamble, the Environmental 
Protection Agency amends title 40, chapter I, part 60 of the Code of 
Federal Regulations as follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

0
1. The authority citation for part 60 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart A--General Provisions

0
2. Amend Sec.  60.17 by:
0
a. Revising paragraph (a), paragraphs (c) introductory text, (d) 
introductory text, and (e) introductory text, and paragraph (g)(14);
0
b. In paragraph (h):
0
i. Redesignating paragraphs (h)(221) through (228) as (h)(226) through 
(233), (h)(196) through (220) as (h)(200) through (224), (h)(171) 
through (195) as (h)(174) through (198), (h)(115) through (170) as 
(h)(117) through (172), and (h)(28) through (114) as (h)(29) through 
(115);
0
ii. Adding new paragraph (h)(28);
0
iii. Revising newly redesignated paragraph (h)(78);
0
iv Adding new paragraphs (h)(116), (173), and (199);
0
v. Revising newly redesignated paragraphs (h)(217) and (221), and
0
vi. Adding new paragraph (h)(225); and
0
c. Revising and republishing paragraph (j); and
0
d. Removing note 1 to paragraph (k).
    The revisions and additions read as follows:


Sec.  60.17  Incorporations by reference.

    (a)(1) Certain material is incorporated by reference into this part 
with the approval of the Director of the Federal Register under 5 
U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other than that 
specified in this section, the U.S. Environmental Protection Agency 
(EPA) must publish a document in the Federal Register and the material 
must be available to the public. All approved incorporation by 
reference (IBR) material is available for inspection at the EPA and at 
the National Archives and Records Administration (NARA). Contact the 
EPA at: EPA Docket Center, Public Reading Room, EPA WJC West, Room 
3334, 1301 Constitution Ave. NW, Washington, DC; phone: (202) 566-1744. 
For information on the availability of this material at NARA, visit 
www.archives.gov/federal-register/cfr/ibr-locations or email 
[email protected].
    (2) The IBR material may be obtained from the sources in the 
following paragraphs of this section or from one or more private 
resellers listed in this paragraph (a)(2). For material that is no 
longer commercially available, contact: the EPA (see paragraph (a)(1) 
of this section).
    (i) Accuris Standards Store, 321 Inverness Drive, South Englewood, 
CO 80112; phone: (800) 332-6077; website: https://store.accuristech.com.
    (ii) American National Standards Institute (ANSI), see paragraph 
(d) of this section.
    (iii) GlobalSpec, 257 Fuller Road, Suite NFE 1100, Albany, NY 
12203-3621; phone: (800) 261-2052; website: https://standards.globalspec.com.
    (iv) Nimonik Document Center, 401 Roland Way, Suite 224, Oakland, 
CA 94624; phone (650) 591-7600; email: center.com">info@document-center.com; 
website: www.document-center.com.
    (v) Techstreet, phone: (855) 999-9870; email: [email protected]; 
website: www.techstreet.com.
* * * * *
    (c) American Hospital Association (AHA) Service, Inc., Post Office 
Box 92683, Chicago, Illinois 60675-2683.
* * * * *
    (d) American National Standards Institute (ANSI), 25 West 43rd 
Street, Fourth Floor, New York, NY 10036-7417; phone: (212) 642-4980; 
email: [email protected]; website: www.ansi.org.
* * * * *
    (e) American Petroleum Institute (API), 200 Massachusetts Ave. NW, 
Suite 1100, Washington, DC 20001; phone: (202) 682-8000; website: 
www.api.org.
* * * * *
    (g) * * *
    (14) ASME/ANSI PTC 19.10-1981, Flue and Exhaust Gas Analyses [Part 
10, Instruments and Apparatus], Issued August 31, 1981; IBR approved 
for Sec. Sec.  60.56c(b); 60.63(f); 60.106(e); 60.104a(d), (h), (i), 
and (j); 60.105a(b), (d), (f), and (g); 60.106a(a); 60.107a(a), (c), 
and (d); 60.275(e); 60.275a(e); 60.275b(e); tables 1 and 3 to subpart 
EEEE; tables 2 and 4 to subpart FFFF; table 2 to subpart JJJJ; 
Sec. Sec.  60.285a(f); 60.396(a); 60.614a(b); 60.664a(b); 60.704(b); 
60.704a(b); 60.2145(s) and (t); 60.2710(s) and (t); 60.2730(q); 
60.4415(a); 60.4900(b); 60.5220(b); tables 1 and 2 to subpart LLLL; 
tables 2 and 3 to subpart MMMM; Sec. Sec.  60.5406(c); 60.5406a(c); 
60.5406b(c); 60.5407a(g); 60.5407b(g); 60.5413(b); 60.5413a(b) and (d); 
60.5413b(d) and (d); 60.5413c(b) and (d).
* * * * *
    (h) * * *
    (28) ASTM D240-19, Standard Test Method for Heat of Combustion of 
Liquid Hydrocarbon Fuels by Bomb Calorimeter, approved November 1, 
2019; IBR approved for Sec.  60.485b(g).
* * * * *
    (78) ASTM D1945-14 (Reapproved 2019), Standard Test Method for 
Analysis of Natural Gas by Gas Chromatography, approved December 1, 
2019; IBR approved for Sec.  60.485b(g).
* * * * *
    (116) ASTM D2879-23, Standard Test Method for Vapor Pressure-
Temperature Relationship and Initial Decomposition Temperature of 
Liquids by Isoteniscope, approved December 1, 2019; IBR approved for 
Sec.  60.485b(e).
* * * * *
    (173) ASTM D4809-18, Standard Test Method for Heat of Combustion of 
Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method), 
approved July 1, 2018; IBR approved for Sec.  60.485b(g).
* * * * *
    (199) ASTM D6420-18, Standard Test Method for Determination of 
Gaseous Organic Compounds by Direct Interface Gas Chromatography-Mass 
Spectrometry, approved November 1, 2018, IBR approved for Sec. Sec.  
60.485(g); 60.485a(g); 60.485b(g); 60.611a;

[[Page 43068]]

60.614(b) and (e); 60.614a(b) and (e), 60.664(b) and (e); 60.664a(b) 
and (f); 60.700(c); 60.704(b) (d), and (h); 60.705(l); 60.704a(b) and 
(f).
* * * * *
    (217) ASTM E168-16 (Reapproved 2023), Standard Practices for 
General Techniques of Infrared Quantitative Analysis, approved January 
1, 2023; IBR approved for Sec.  60.485b(d).
* * * * *
    (221) ASTM E169-16 (Reapproved 2022), Standard Practices for 
General Techniques of Ultraviolet-Visible Quantitative Analysis, 
approved November 1, 2022; IBR approved for Sec.  60.485b(d).
* * * * *
    (225) ASTM E260-96 (Reapproved 2019), Standard Practice for Packed 
Column Gas Chromatography, approved September 1, 2029; IBR approved for 
Sec.  60.485b(d).
* * * * *
    (j) U.S. Environmental Protection Agency (EPA), 1200 Pennsylvania 
Avenue NW, Washington, DC 20460; phone: (202) 272-0167; website: 
www.epa.gov/aboutepa/forms/contact-epa.
    (1) EPA-453/R-08-002, Protocol for Determining the Daily Volatile 
Organic Compound Emission Rate of Automobile and Light-Duty Truck 
Primer-Surfacer and Topcoat Operations, September 2008, Office of Air 
Quality Planning and Standards (OAQPS); IBR approved for Sec. Sec.  
60.393a(e) and (h); 60.395a(k); 60.397a(e); appendix A to subpart MMa.
    (2) EPA-454/B-08-002, Quality Assurance Handbook for Air Pollution 
Measurement Systems; Volume IV: Meteorological Measurements, Version 
2.0 (Final), March 2008; IBR approved for appendix K to this part.
    (3) EPA-454/R-98-015, Office of Air Quality Planning and Standards 
(OAQPS), Fabric Filter Bag Leak Detection Guidance, September 1997; IBR 
approved for Sec. Sec.  60.124(f); 60.124a(f); 60.273(e); 60.273a(e); 
60.273b(e); 60.373a(b); 60.2145(r); 60.2710(r); 60.4905(b); 60.5225(b). 
(Available from: https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=2000D5T6.pdf).
    (4) EPA-600/R-12/531, EPA Traceability Protocol for Assay and 
Certification of Gaseous Calibration Standards, May 2012; IBR approved 
for Sec. Sec.  60.5413(d); 60.5413a(d); 60.5413b(d); 60.5413c(d).
    (5) In EPA Publication No. SW-846, Test Methods for Evaluating 
Solid Waste, Physical/Chemical Methods (Available from: www.epa.gov/hw-sw846/sw-846-compendium):
    (i) SW-846-6010D, Inductively Coupled Plasma-Optical Emission 
Spectrometry, Revision 5, July 2018; IBR approved for appendix A-5 to 
this part.
    (ii) SW-846-6020B, Inductively Coupled Plasma-Mass Spectrometry, 
Revision 2, July 2014; IBR approved for appendix A-5 to this part.
* * * * *

0
3. Amend Sec.  60.480 by revising paragraph (f) to read as follows:


Sec.  60.480  Applicability and designation of affected facility.

* * * * *
    (f) Overlap with other regulations for flares. Owners and operators 
of flares that are subject to the flare related requirements of this 
subpart and flare related requirements of any other regulation in this 
part or 40 CFR 61 or 63, may elect to comply with the requirements in 
Sec.  60.619a, Sec.  60.669a, or Sec.  60.709a, in lieu of all flare 
related requirements in any other regulation in this part or 40 CFR 
part 61 or 63.

0
4. Amend Sec.  60.481 by revising the definition of ``Process unit'' to 
read as follows:


Sec.  60.481  Definitions.

* * * * *
    Process unit means components assembled to produce, as intermediate 
or final products, one or more of the chemicals listed in Sec.  60.489 
of this part. A process unit can operate independently if supplied with 
sufficient feed or raw materials and sufficient storage facilities for 
the product.
* * * * *


Sec.  60.482-1  [Amended]

0
5. Amend Sec.  60.482-1 by removing paragraph (g).

0
6. Amend Sec.  60.485 by revising paragraph (g)(5) to read as follows:


Sec.  60.485  Test methods and procedures.

* * * * *
    (g) * * *
    (5) Method 18 of appendix A-6 to this part and ASTM D2504-67, 77 or 
88 (Reapproved 1993) (incorporated by reference, see Sec.  60.17) shall 
be used to determine the concentration of sample component ``i.'' ASTM 
D6420-18 (incorporated by reference, see Sec.  60.17) may be used in 
lieu of Method 18, under the conditions specified in paragraphs 
(g)(5)(i) through (iii) of this section.
    (i) If the target compounds are all known and are all listed in 
Section 1.1 of ASTM D6420-18 as measurable.
    (ii) ASTM D6420-18 may not be used for methane and ethane.
    (iii) ASTM D6420-18 may not be used as a total VOC method.
* * * * *

0
7. Amend Sec.  60.486 by adding paragraph (l) as follows:


Sec.  60.486  Recordkeeping requirements.

* * * * *
    (l) Any records required to be maintained by this subpart that are 
submitted electronically via the EPA's Compliance and Emissions Data 
Reporting Interface (CEDRI) may be maintained in electronic format. 
This ability to maintain electronic copies does not affect the 
requirement for facilities to make records, data, and reports available 
upon request to a delegated air agency or the EPA as part of an on-site 
compliance evaluation.

0
8. Amend Sec.  60.487 by revising paragraphs (a) and (f) and adding 
paragraphs (g), (h), and (i) to read as follows:


Sec.  60.487  Reporting requirements.

    (a) Each owner or operator subject to the provisions of this 
subpart shall submit semiannual reports to the Administrator beginning 
six months after the initial startup date. Beginning on July 15, 2025, 
or once the report template for this subpart has been available on the 
CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 year, whichever date is later, submit all subsequent 
reports using the appropriate electronic report template on the CEDRI 
website for this subpart and following the procedure specified in 
paragraph (g) of this section. The date report templates become 
available will be listed on the CEDRI website. Unless the Administrator 
or delegated state agency or other authority has approved a different 
schedule for submission of reports, the report must be submitted by the 
deadline specified in this subpart, regardless of the method in which 
the report is submitted.
* * * * *
    (f) The requirements of paragraphs (a) through (c) of this section 
remain in force until and unless EPA, in delegating enforcement 
authority to a State under section 111(c) of the Act, approves 
reporting requirements or an alternative means of compliance 
surveillance adopted by such State. In that event, affected sources 
within the State will be relieved of the obligation to comply with the 
requirements of paragraphs (a) through (c) of this section, provided 
that they comply with the requirements established by the State. The 
EPA will not approve a waiver of electronic reporting to the

[[Page 43069]]

EPA in delegating enforcement authority. Thus, electronic reporting to 
the EPA cannot be waived, and as such, the provisions of this paragraph 
cannot be used to relieve owners or operators of affected facilities of 
the requirement to submit the electronic reports required in this 
section to the EPA.
    (g) If an owner or operator is required to submit notifications or 
reports following the procedure specified in this paragraph (g), the 
owner or operator must submit notifications or reports to the EPA via 
CEDRI, which can be accessed through the EPA's Central Data Exchange 
(CDX) (https://cdx.epa.gov/). The EPA will make all the information 
submitted through CEDRI available to the public without further notice 
to the owner or operator. Do not use CEDRI to submit information the 
owner or operator claims as CBI. Although the EPA does not expect 
persons to assert a claim of CBI, if an owner or operator wishes to 
assert a CBI claim for some of the information in the report or 
notification, the owner or operator must submit a complete file in the 
format specified in this subpart, including information claimed to be 
CBI, to the EPA following the procedures in paragraphs (g)(1) and (2) 
of this section. Clearly mark the part or all of the information 
claimed to be CBI. Information not marked as CBI may be authorized for 
public release without prior notice. Information marked as CBI will not 
be disclosed except in accordance with procedures set forth in 40 CFR 
part 2. All CBI claims must be asserted at the time of submission. 
Anything submitted using CEDRI cannot later be claimed CBI. 
Furthermore, under CAA section 114(c), emissions data is not entitled 
to confidential treatment, and the EPA is required to make emissions 
data available to the public. Thus, emissions data will not be 
protected as CBI and will be made publicly available. The owner or 
operator must submit the same file submitted to the CBI office with the 
CBI omitted to the EPA via the EPA's CDX as described earlier in this 
paragraph (g).
    (1) The preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
[email protected], and as described above, should include clear CBI 
markings. ERT files should be flagged to the attention of the Group 
Leader, Measurement Policy Group; all other files should be flagged to 
the attention of the SOCMI NSPS Sector Lead. Owners and operators who 
do not have their own file sharing service and who require assistance 
with submitting large electronic files that exceed the file size limit 
for email attachments should email [email protected] to request a file 
transfer link.
    (2) If an owner or operator cannot transmit the file 
electronically, the owner or operator may send CBI information through 
the postal service to the following address: OAQPS Document Control 
Officer (C404-02), OAQPS, U.S. Environmental Protection Agency, 109 
T.W. Alexander Drive, P.O. Box 12055, Research Triangle Park, North 
Carolina 27711. ERT files should be sent to the attention of the Group 
Leader, Measurement Policy Group, and all other files should be sent to 
the attention of the SOCMI NSPS Sector Lead. The mailed CBI material 
should be double wrapped and clearly marked. Any CBI markings should 
not show through the outer envelope.
    (h) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX may assert a 
claim of EPA system outage for failure to timely comply with that 
reporting requirement. To assert a claim of EPA system outage, owner 
and operator must meet the requirements outlined in paragraphs (h)(1) 
through (7) of this section.
    (1) The owner or operator must have been or will be precluded from 
accessing CEDRI and submitting a required report within the time 
prescribed due to an outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (5) The owner or operator must provide to the Administrator a 
written description identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which the owner or operator proposes to report, or 
if the owner or operator has already met the reporting requirement at 
the time of the notification, the date the report was submitted.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (i) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX may assert a 
claim of force majeure for failure to timely comply with that reporting 
requirement. To assert a claim of force majeure, owners and operators 
must meet the requirements outlined in paragraphs (i)(1) through (5) of 
this section.
    (1) The owner or operator may submit a claim if a force majeure 
event is about to occur, occurs, or has occurred or there are lingering 
effects from such an event within the period of time beginning five 
business days prior to the date the submission is due. For the purposes 
of this section, a force majeure event is defined as an event that will 
be or has been caused by circumstances beyond the control of the 
affected facility, its contractors, or any entity controlled by the 
affected facility that prevents the owner or operator from complying 
with the requirement to submit a report electronically within the time 
period prescribed. Examples of such events are acts of nature (e.g., 
hurricanes, earthquakes, or floods), acts of war or terrorism, or 
equipment failure or safety hazard beyond the control of the affected 
facility (e.g., large scale power outage).
    (2) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (3) The owner or operator must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which the owner or operator proposes to report, or 
if the owner or operator has already met the reporting requirement at 
the time of the notification, the date the report was submitted.

[[Page 43070]]

    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.

0
9. Revise the heading of subpart VVa to read as follows:

Subpart VVa--Standards of Performance for Equipment Leaks of VOC in 
the Synthetic Organic Chemicals Manufacturing Industry for Which 
Construction, Reconstruction, or Modification Commenced After 
November 7, 2006, and on or Before April 25, 2023

0
10. Amend Sec.  60.480a by revising paragraphs (b), revising and 
republishing paragraph (d), and revising paragraph (f) to read as 
follows:


Sec.  60.480a  Applicability and designation of affected facility.

* * * * *
    (b) Any affected facility under paragraph (a) of this section that 
commences construction, reconstruction, or modification after November 
7, 2006, and on or before April 25, 2023, shall be subject to the 
requirements of this subpart.
* * * * *
    (d)(1) If an owner or operator applies for one or more of the 
exemptions in this paragraph, then the owner or operator shall maintain 
records as required in Sec.  60.486a(i).
    (2) Any affected facility that has the design capacity to produce 
less than 1,000 Mg/yr (1,102 ton/yr) of a chemical listed in Sec.  
60.489 is exempt from Sec. Sec.  60.482-1a through 60.482-10a.
    (3) If an affected facility produces heavy liquid chemicals only 
from heavy liquid feed or raw materials, then it is exempt from 
Sec. Sec.  60.482-1a through 60.482-10a.
    (4) Any affected facility that produces beverage alcohol is exempt 
from Sec. Sec.  60.482-1a through 60.482-10a.
    (5) Any affected facility that has no equipment in volatile organic 
compounds (VOC) service is exempt from Sec. Sec.  60.482-1a through 
60.482-10a.
* * * * *
    (f) Owners and operators of flares that are subject to the flare 
related requirements of this subpart and flare related requirements of 
any other regulation in this part or 40 CFR part 61 or 63, may elect to 
comply with the requirements in Sec.  60.619a, Sec.  60.669a, or Sec.  
60.709a, in lieu of all flare related requirements in any other 
regulation in this part or 40 CFR part 61 or 63.

0
11. Amend Sec.  60.481a by revising the definitions of ``Capital 
expenditure'' and ``Process Unit'' to read as follows:


Sec.  60.481a  Definitions.

* * * * *
    Capital expenditure means, in addition to the definition in Sec.  
60.2, an expenditure for a physical or operational change to an 
existing facility that:
    (1) Exceeds P, the product of the facility's replacement cost, R, 
and an adjusted annual asset guideline repair allowance, A, as 
reflected by the following equation: P = R x A, where:
    (i) The adjusted annual asset guideline repair allowance, A, is the 
product of the percent of the replacement cost, Y, and the applicable 
basic annual asset guideline repair allowance, B, divided by 100 as 
reflected by the following equation:
Equation 1 to Capital Expenditure Paragraph (1)(i)
A = Y x (B / 100);

    (ii) The percent Y is determined from the following equation: Y = 
1.0 - 0.575 log X, where X is:
    (A) 2006 minus the year of construction if the physical or 
operational change to the existing facility was on or after November 
16, 2007, or
    (B) 1982 minus the year of construction if the physical or 
operational change to the existing facility was prior to November 16, 
2007; and
    (iii) The applicable basic annual asset guideline repair allowance, 
B, is selected from the following table consistent with the applicable 
subpart:

     Table 1 to Capital Expenditure Paragraph (1)(iii)--Determining
                         Applicable Value for B
------------------------------------------------------------------------
                                                       Value of B to be
           Subpart applicable to facility              used in equation
------------------------------------------------------------------------
(A) VVa.............................................                12.5
(B) GGGa............................................                 7.0
------------------------------------------------------------------------

* * * * *
    Process unit means components assembled to produce, as intermediate 
or final products, one or more of the chemicals listed in Sec.  
60.489a. A process unit can operate independently if supplied with 
sufficient feed or raw materials and sufficient storage facilities for 
the product.
* * * * *

0
12. Amend Sec.  60.482-1a by revising paragraph (e) introductory text 
and removing paragraph (g).
    The revision reads as follows:


Sec.  60.482-1a  Standards: General.

* * * * *
    (e) Equipment that an owner or operator designates as being in VOC 
service less than 300 hr/yr is excluded from the requirements of 
Sec. Sec.  60.482-2a through 60.482-10a if it is identified as required 
in Sec.  60.486a(e)(6) and it meets any of the conditions specified in 
paragraphs (e)(1) through (3) of this section.
* * * * *


Sec.  60.482-11a  [Removed]

0
13. Remove Sec.  60.482-11a.

0
14. Amend Sec.  60.485a by revising paragraphs (b) and (g)(5) to read 
as follows:


Sec.  60.485a  Test methods and procedures.

* * * * *
    (b) The owner or operator shall determine compliance with the 
standards in Sec. Sec.  60.482-1a through 60.482-10a, 60.483a, and 
60.484a as follows:
    (1) Method 21 shall be used to determine the presence of leaking 
sources. The instrument shall be calibrated before use each day of its 
use by the procedures specified in Method 21 of appendix A-7 of this 
part. The following calibration gases shall be used:
    (i) Zero air (less than 10 ppm of hydrocarbon in air); and
    (ii) A mixture of methane or n-hexane and air at a concentration no 
more than 2,000 ppm greater than the leak definition concentration of 
the equipment monitored. If the monitoring instrument's design allows 
for multiple calibration scales, then the lower scale shall be 
calibrated with a calibration gas that is no higher than 2,000 ppm 
above the concentration specified as a leak, and the highest scale 
shall be calibrated

[[Page 43071]]

with a calibration gas that is approximately equal to 10,000 ppm. If 
only one scale on an instrument will be used during monitoring, the 
owner or operator need not calibrate the scales that will not be used 
during that day's monitoring.
    (2) A calibration drift assessment shall be performed, at a 
minimum, at the end of each monitoring day. Check the instrument using 
the same calibration gas(es) that were used to calibrate the instrument 
before use. Follow the procedures specified in Method 21 of appendix A-
7 to this part, section 10.1, except do not adjust the meter readout to 
correspond to the calibration gas value. Record the instrument reading 
for each scale used as specified in Sec.  60.486a(e)(8). Divide the 
arithmetic difference of the initial and post-test calibration response 
by the corresponding calibration gas value for each scale and multiply 
by 100 to express the calibration drift as a percentage.
    (i) If a calibration drift assessment shows a negative drift of 
more than 10 percent, then all equipment with instrument readings 
between the appropriate leak definition and the leak definition 
multiplied by (100 minus the percent of negative drift/divided by 100) 
that was monitored since the last calibration must be re-monitored.
    (ii) If any calibration drift assessment shows a positive drift of 
more than 10 percent from the initial calibration value, then, at the 
owner/operator's discretion, all equipment with instrument readings 
above the appropriate leak definition and below the leak definition 
multiplied by (100 plus the percent of positive drift/divided by 100) 
monitored since the last calibration may be re-monitored.
* * * * *
    (g) * * *
    (5) Method 18 of appendix A-6 to this part and ASTM D2504-67, 77, 
or 88 (Reapproved 1993) (incorporated by reference, see Sec.  60.17) 
shall be used to determine the concentration of sample component ``i.'' 
ASTM D6420-18 (incorporated by reference, see Sec.  60.17) may be used 
in lieu of Method 18, under the conditions specified in paragraphs 
(g)(5)(i) through (iii) of this section.
    (i) If the target compounds are all known and are all listed in 
Section 1.1 of ASTM D6420-18 as measurable.
    (ii) ASTM D6420-18 may not be used for methane and ethane.
    (iii) ASTM D6420-18 may not be used as a total VOC method.
* * * * *

0
15. Amend Sec.  60.486a by:
0
a. Revising paragraphs (a)(3) introductory text and (b) introductory 
text;
0
b. Removing and reserving paragraph (b)(3);
0
c. Revising paragraphs (c) introductory text and (e) introductory text;
0
d. Removing and reserving paragraph (e)(9);
0
e. Revising paragraph (f) introductory text; and
0
f. Adding paragraph (l).
    The revisions and addition read as follows:


Sec.  60.486a  Recordkeeping requirements.

    (a) * * *
    (3) The owner or operator shall record the information specified in 
paragraphs (a)(3)(i) through (v) of this section for each monitoring 
event required by Sec. Sec.  60.482-2a, 60.482-3a, 60.482-7a, 60.482-
8a, and 60.483-2a.
* * * * *
    (b) When each leak is detected as specified in Sec. Sec.  60.482-
2a, 60.482-3a, 60.482-7a, 60.482-8a, and 60.483-2a, the following 
requirements apply:
* * * * *
    (c) When each leak is detected as specified in Sec. Sec.  60.482-
2a, 60.482-3a, 60.482-7a, 60.482-8a, and 60.483-2a, the following 
information shall be recorded in a log and shall be kept for 2 years in 
a readily accessible location:
* * * * *
    (e) The following information pertaining to all equipment subject 
to the requirements in Sec. Sec.  60.482-1a to 60.482-10a shall be 
recorded in a log that is kept in a readily accessible location:
* * * * *
    (f) The following information pertaining to all valves subject to 
the requirements of Sec.  60.482-7a(g) and (h), and all pumps subject 
to the requirements of Sec.  60.482-2a(g) shall be recorded in a log 
that is kept in a readily accessible location:
* * * * *
    (l) Any records required to be maintained by this subpart that are 
submitted electronically via the EPA's Compliance and Emissions Data 
Reporting Interface (CEDRI) may be maintained in electronic format. 
This ability to maintain electronic copies does not affect the 
requirement for facilities to make records, data, and reports available 
upon request to a delegated air agency or the EPA as part of an on-site 
compliance evaluation.

0
16. Amend Sec.  60.487a by:
0
a. Revising paragraph (a);
0
b. Removing paragraph (b)(5);
0
c. Revising paragraph (c)(2)(vi);
0
d. Removing and reserving paragraphs (c)(2)(vii) and (viii):
0
e. Revising paragraph (f); and
0
f. Adding paragraphs (g), (h) and (i).
    The revisions and additions read as follows:


Sec.  60.487a  Reporting requirements.

    (a) Each owner or operator subject to the provisions of this 
subpart shall submit semiannual reports to the Administrator beginning 
6 months after the initial startup date. Beginning on July 15, 2025, or 
once the report template for this subpart has been available on the 
CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 year, whichever date is later, submit all subsequent 
reports using the appropriate electronic report template on the CEDRI 
website for this subpart and following the procedure specified in 
paragraph (g) of this section. The date report templates become 
available will be listed on the CEDRI website. Unless the Administrator 
or delegated state agency or other authority has approved a different 
schedule for submission of reports, the report must be submitted by the 
deadline specified in this subpart, regardless of the method in which 
the report is submitted.
* * * * *
    (c) * * *
    (2) * * *
    (vi) Number of compressors for which leaks were not repaired as 
required in Sec.  60.482-3a(g)(1), and
* * * * *
    (f) The requirements of paragraphs (a) through (c) of this section 
remain in force until and unless EPA, in delegating enforcement 
authority to a state under section 111(c) of the CAA, approves 
reporting requirements or an alternative means of compliance 
surveillance adopted by such state. In that event, affected sources 
within the state will be relieved of the obligation to comply with the 
requirements of paragraphs (a) through (c) of this section, provided 
that they comply with the requirements established by the state. The 
EPA will not approve a waiver of electronic reporting to the EPA in 
delegating enforcement authority. Thus, electronic reporting to the EPA 
cannot be waived, and as such, the provisions of this paragraph cannot 
be used to relieve owners or operators of affected facilities of the 
requirement to submit the electronic reports required in this section 
to the EPA.
    (g) If an owner or operator is required to submit notifications or 
reports following the procedure specified in this paragraph (g), the 
owner or operator

[[Page 43072]]

must submit notifications or reports to the EPA via CEDRI, which can be 
accessed through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/). The EPA will make all the information submitted through 
CEDRI available to the public without further notice to the owner or 
operator. Do not use CEDRI to submit information the owner or operator 
claims as CBI. Although the EPA does not expect persons to assert a 
claim of CBI, if you an owner or operator wishes to assert a CBI claim 
for some of the information in the report or notification, the owner or 
operator must submit a complete file in the format specified in this 
subpart, including information claimed to be CBI, to the EPA following 
the procedures in paragraphs (g)(1) and (2) of this section. Clearly 
mark the part or all of the information claimed to be CBI. Information 
not marked as CBI may be authorized for public release without prior 
notice. Information marked as CBI will not be disclosed except in 
accordance with procedures set forth in 40 CFR part 2. All CBI claims 
must be asserted at the time of submission. Anything submitted using 
CEDRI cannot later be claimed CBI. Furthermore, under CAA section 
114(c), emissions data is not entitled to confidential treatment, and 
the EPA is required to make emissions data available to the public. 
Thus, emissions data will not be protected as CBI and will be made 
publicly available. The owner or operator must submit the same file 
submitted to the CBI office with the CBI omitted to the EPA via the 
EPA's CDX as described earlier in this paragraph (g).
    (1) The preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
[email protected], and as described above, should include clear CBI 
markings. ERT files should be flagged to the attention of the Group 
Leader, Measurement Policy Group; all other files should be flagged to 
the attention of the SOCMI NSPS Sector Lead. Owners and operators who 
do not have their own file sharing service and who require assistance 
with submitting large electronic files that exceed the file size limit 
for email attachments should email [email protected] to request a file 
transfer link.
    (2) If an owner or operator cannot transmit the file 
electronically, the owner or operator may send CBI information through 
the postal service to the following address: OAQPS Document Control 
Officer (C404-02), OAQPS, U.S. Environmental Protection Agency, 109 
T.W. Alexander Drive, P.O. Box 12055, Research Triangle Park, North 
Carolina 27711. ERT files should be sent to the attention of the Group 
Leader, Measurement Policy Group, and all other files should be sent to 
the attention of the SOCMI NSPS Sector Lead. The mailed CBI material 
should be double wrapped and clearly marked. Any CBI markings should 
not show through the outer envelope.
    (h) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX may assert a 
claim of EPA system outage for failure to timely comply with that 
reporting requirement. To assert a claim of EPA system outage, owners 
and operators must meet the requirements outlined in paragraphs (h)(1) 
through (7) of this section.
    (1) The owner or operator must have been or will be precluded from 
accessing CEDRI and submitting a required report within the time 
prescribed due to an outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (5) The owner or operator must provide to the Administrator a 
written description identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which the owner or operator proposes to report, or 
if the owner or operator has already met the reporting requirement at 
the time of the notification, the date the report was submitted.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (i) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX may assert a 
claim of force majeure for failure to timely comply with that reporting 
requirement. To assert a claim of force majeure, owners and operators 
must meet the requirements outlined in paragraphs (i)(1) through (5) of 
this section.
    (1) An owner or operator may submit a claim if a force majeure 
event is about to occur, occurs, or has occurred or there are lingering 
effects from such an event within the period of time beginning five 
business days prior to the date the submission is due. For the purposes 
of this section, a force majeure event is defined as an event that will 
be or has been caused by circumstances beyond the control of the 
affected facility, its contractors, or any entity controlled by the 
affected facility that prevents the owner or operator from complying 
with the requirement to submit a report electronically within the time 
period prescribed. Examples of such events are acts of nature (e.g., 
hurricanes, earthquakes, or floods), acts of war or terrorism, or 
equipment failure or safety hazard beyond the control of the affected 
facility (e.g., large scale power outage).
    (2) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (3) The owner or operator must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which the owner or operator proposes to report, or 
if the owner or operator has already met the reporting requirement at 
the time of the notification, the date the report was submitted.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.

0
17. Add subpart VVb to read as follows:

[[Page 43073]]

Subpart VVb--Standards of Performance for Equipment Leaks of VOC in the 
Synthetic Organic Chemicals Manufacturing Industry for Which 
Construction, Reconstruction, or Modification Commenced After April 25, 
2023
Sec.
60.480b Applicability and designation of affected facility.
60.481b Definitions.
60.482-1b Standards: General.
60.482-2b Standards: Pumps in light liquid service.
60.482-3b Standards: Compressors.
60.482-4b Standards: Pressure relief devices in gas/vapor service.
60.482-5b Standards: Sampling connection systems.
60.482-6b Standards: Open-ended valves or lines.
60.482-7b Standards: Valves in gas/vapor service and in light liquid 
service.
60.482-8b Standards: Pumps, valves, and connectors in heavy liquid 
service and pressure relief devices in light liquid or heavy liquid 
service.
60.482-9b Standards: Delay of repair.
60.482-10b Standards: Closed vent systems and control devices.
60.482-11b Standards: Connectors in gas/vapor service and in light 
liquid service.
60.483-1b Alternative standards for valves--allowable percentage of 
valves leaking.
60.483-2b Alternative standards for valves--skip period leak 
detection and repair.
60.484b Equivalence of means of emission limitation.
60.485b Test methods and procedures.
60.486b Recordkeeping requirements.
60.487b Reporting requirements.
60.488b Reconstruction.
60.489b List of chemicals produced by affected facilities.

Subpart VVb--Standards of Performance for Equipment Leaks of VOC in 
the Synthetic Organic Chemicals Manufacturing Industry for Which 
Construction, Reconstruction, or Modification Commenced After April 
25, 2023

Sec.  60.480b Applicability and designation of affected facility.

    (a)(1) The provisions of this subpart apply to affected facilities 
in the synthetic organic chemicals manufacturing industry.
    (2) The group of all equipment (defined in Sec.  60.481b) within a 
process unit is an affected facility.
    (b) Any affected facility under paragraph (a) of this section that 
commences construction, reconstruction, or modification after April 25, 
2023, shall be subject to the requirements of this subpart.
    (c) Addition or replacement of equipment for the purpose of process 
improvement which is accomplished without a capital expenditure shall 
not by itself be considered a modification under this subpart.
    (d)(1) If an owner or operator applies for one or more of the 
exemptions in this paragraph, then the owner or operator shall maintain 
records as required in Sec.  60.486b(i).
    (2) Any affected facility that has the design capacity to produce 
less than 1,000 Mg/yr (1,102 ton/yr) of a chemical listed in Sec.  
60.489 is exempt from Sec. Sec.  60.482-1b through 60.482-11b.
    (3) If an affected facility produces heavy liquid chemicals only 
from heavy liquid feed or raw materials, then it is exempt from 
Sec. Sec.  60.482-1b through 60.482-11b.
    (4) Any affected facility that produces beverage alcohol is exempt 
from Sec. Sec.  60.482-1b through 60.482-11b.
    (5) Any affected facility that has no equipment in volatile organic 
compounds (VOC) service is exempt from Sec. Sec.  60.482-1b through 
60.482-11b.
    (e)(1) Option to comply with 40 CFR part 65. (i) Owners or 
operators may choose to comply with the provisions of 40 CFR part 65, 
subpart F, to satisfy the requirements of Sec. Sec.  60.482-1b through 
60.487b for an affected facility. When choosing to comply with 40 CFR 
part 65, subpart F, the requirements of Sec. Sec.  60.485b(d), (e), and 
(f), and 60.486b(i) and (j) still apply. Other provisions applying to 
an owner or operator who chooses to comply with 40 CFR part 65 are 
provided in 40 CFR 65.1.
    (ii) Owners or operators who choose to comply with 40 CFR part 65, 
subpart F must also comply with Sec. Sec.  60.1, 60.2, 60.5, 60.6, 
60.7(a)(1) and (4), 60.14, 60.15, and 60.16 for that equipment. All 
sections and paragraphs that are not mentioned in this paragraph 
(e)(1)(ii) do not apply to owners or operators of equipment subject to 
this subpart complying with 40 CFR part 65, subpart F, except that 
provisions required to be met prior to implementing 40 CFR part 65 
still apply. Owners and operators who choose to comply with 40 CFR part 
65, subpart F, must comply with 40 CFR part 65, subpart A.
    (2) Option to comply with 40 CFR part 63, subpart H. (i) Owners or 
operators may choose to comply with the provisions of 40 CFR part 63, 
subpart H, to satisfy the requirements of Sec. Sec.  60.482-1b through 
60.487b for an affected facility. When choosing to comply with 40 CFR 
part 63, subpart H, the requirements of Sec.  60.482-7b, Sec.  
60.485b(d), (e), and (f), and Sec.  60.486b(i) and (j) still apply.
    (ii) Owners or operators who choose to comply with 40 CFR part 63, 
subpart H must also comply with Sec. Sec.  60.1, 60.2, 60.5, 60.6, 
60.7(a)(1) and (4), 60.14, 60.15, and 60.16 for that equipment. All 
sections and paragraphs that are not mentioned in this paragraph 
(e)(2)(ii) do not apply to owners or operators of equipment subject to 
this subpart complying with 40 CFR part 63, subpart H, except that 
provisions required to be met prior to implementing 40 CFR part 63 
still apply. Owners and operators who choose to comply with 40 CFR part 
63, subpart H, must comply with 40 CFR part 63, subpart A.
    (f) Owners and operators of flares that are subject to the flare 
related requirements of this subpart and flare related requirements of 
any other regulation in this part or 40 CFR part 61 or 63, may elect to 
comply with the requirements in Sec.  60.619a, Sec.  60.669a, or Sec.  
60.709a, in lieu of all flare related requirements in any other 
regulation in this part or 40 CFR part 61 or 63.


Sec.  60.481b  Definitions.

    As used in this subpart, all terms not defined herein shall have 
the meaning given them in the Clean Air Act (CAA) or in subpart A of 
this part, and the following terms shall have the specific meanings 
given them.
    Capital expenditure means, in addition to the definition in Sec.  
60.2, an expenditure for a physical or operational change to an 
existing facility that:
    (1) Exceeds P, the product of the facility's replacement cost, R, 
and an adjusted annual asset guideline repair allowance, A, as 
reflected by the following equation: P = R x A, where:
    (i) The adjusted annual asset guideline repair allowance, A, is the 
product of the percent of the replacement cost, Y, and the applicable 
basic annual asset guideline repair allowance, B, divided by 100 as 
reflected by the following equation:
Equation 1 to Capital Expenditure Paragraph (1)(i)
A = Y x (B / 100);

    (ii) The percent Y is determined from the following equation: Y = 
(CPI of date of construction/most recently available CPI of date of 
project), where the ``CPI-U, U.S. city average, all items'' must be 
used for each CPI value; and
    (iii) The applicable basic annual asset guideline repair allowance, 
B, is 12.5.
    Closed-loop system means an enclosed system that returns process 
fluid to the process.
    Closed-purge system means a system or combination of systems and 
portable containers to capture purged liquids. Containers for purged 
liquids must be covered or closed when not being filled or emptied.
    Closed vent system means a system that is not open to the 
atmosphere and

[[Page 43074]]

that is composed of hard-piping, ductwork, connections, and, if 
necessary, flow-inducing devices that transport gas or vapor from a 
piece or pieces of equipment to a control device or back to a process.
    Connector means flanged, screwed, or other joined fittings used to 
connect two pipe lines or a pipe line and a piece of process equipment 
or that close an opening in a pipe that could be connected to another 
pipe. Joined fittings welded completely around the circumference of the 
interface are not considered connectors for the purpose of this 
regulation.
    Control device means an enclosed combustion device, vapor recovery 
system, or flare.
    Distance piece means an open or enclosed casing through which the 
piston rod travels, separating the compressor cylinder from the 
crankcase.
    Double block and bleed system means two block valves connected in 
series with a bleed valve or line that can vent the line between the 
two block valves.
    Duct work means a conveyance system such as those commonly used for 
heating and ventilation systems. It is often made of sheet metal and 
often has sections connected by screws or crimping. Hard-piping is not 
ductwork.
    Equipment means each pump, compressor, pressure relief device, 
sampling connection system, open-ended valve or line, valve, and flange 
or other connector in VOC service and any devices or systems required 
by this subpart.
    First attempt at repair means to take action for the purpose of 
stopping or reducing leakage of organic material to the atmosphere 
using best practices.
    Fuel gas means gases that are combusted to derive useful work or 
heat.
    Fuel gas system means the offsite and onsite piping and flow and 
pressure control system that gathers gaseous stream(s) generated by 
onsite operations, may blend them with other sources of gas, and 
transports the gaseous stream for use as fuel gas in combustion devices 
or in-process combustion equipment, such as furnaces and gas turbines, 
either singly or in combination.
    Hard-piping means pipe or tubing that is manufactured and properly 
installed using good engineering judgment and standards such as ASME 
B31.3, Process Piping (available from the American Society of 
Mechanical Engineers, P.O. Box 2300, Fairfield, NJ 07007-2300).
    In gas/vapor service means that the piece of equipment contains 
process fluid that is in the gaseous state at operating conditions.
    In heavy liquid service means that the piece of equipment is not in 
gas/vapor service or in light liquid service.
    In light liquid service means that the piece of equipment contains 
a liquid that meets the conditions specified in Sec.  60.485b(e).
    In-situ sampling systems means nonextractive samplers or in-line 
samplers.
    In vacuum service means that equipment is operating at an internal 
pressure which is at least 5 kilopascals (kPa) (0.7 psia) below ambient 
pressure.
    In VOC service means that the piece of equipment contains or 
contacts a process fluid that is at least 10 percent VOC by weight. 
(The provisions of Sec.  60.485b(d) specify how to determine that a 
piece of equipment is not in VOC service.)
    Initial calibration value means the concentration measured during 
the initial calibration at the beginning of each day required in Sec.  
60.485b(b)(1), or the most recent calibration if the instrument is 
recalibrated during the day (i.e., the calibration is adjusted) after a 
calibration drift assessment.
    Liquids dripping means any visible leakage from the seal including 
spraying, misting, clouding, and ice formation.
    Open-ended valve or line means any valve, except safety relief 
valves, having one side of the valve seat in contact with process fluid 
and one side open to the atmosphere, either directly or through open 
piping.
    Pressure release means the emission of materials resulting from 
system pressure being greater than set pressure of the pressure relief 
device.
    Process improvement means routine changes made for safety and 
occupational health requirements, for energy savings, for better 
utility, for ease of maintenance and operation, for correction of 
design deficiencies, for bottleneck removal, for changing product 
requirements, or for environmental control.
    Process unit means components assembled to produce, as intermediate 
or final products, one or more of the chemicals listed in Sec.  60.489. 
A process unit can operate independently if supplied with sufficient 
feed or raw materials and sufficient storage facilities for the 
product.
    Process unit shutdown means a work practice or operational 
procedure that stops production from a process unit or part of a 
process unit during which it is technically feasible to clear process 
material from a process unit or part of a process unit consistent with 
safety constraints and during which repairs can be accomplished. The 
following are not considered process unit shutdowns:
    (1) An unscheduled work practice or operational procedure that 
stops production from a process unit or part of a process unit for less 
than 24 hours.
    (2) An unscheduled work practice or operational procedure that 
would stop production from a process unit or part of a process unit for 
a shorter period of time than would be required to clear the process 
unit or part of the process unit of materials and start up the unit and 
would result in greater emissions than delay of repair of leaking 
components until the next scheduled process unit shutdown.
    (3) The use of spare equipment and technically feasible bypassing 
of equipment without stopping production.
    Quarter means a 3-month period; the first quarter concludes on the 
last day of the last full month during the 180 days following initial 
startup.
    Repaired means that equipment is adjusted, or otherwise altered, in 
order to eliminate a leak as defined in the applicable sections of this 
subpart and, except for leaks identified in accordance with Sec. Sec.  
60.482-2b(b)(2)(ii) and (d)(6)(ii) and (iii), 60.482-3b(f), and 60.482-
10b(f)(1)(ii), is re-monitored as specified in Sec.  60.485b(b) to 
verify that emissions from the equipment are below the applicable leak 
definition.
    Replacement cost means the capital needed to purchase all the 
depreciable components in a facility.
    Sampling connection system means an assembly of equipment within a 
process unit used during periods of representative operation to take 
samples of the process fluid. Equipment used to take nonroutine grab 
samples is not considered a sampling connection system.
    Sensor means a device that measures a physical quantity or the 
change in a physical quantity such as temperature, pressure, flow rate, 
pH, or liquid level.
    Storage vessel means a tank or other vessel that is used to store 
organic liquids that are used in the process as raw material 
feedstocks, produced as intermediates or final products, or generated 
as wastes. Storage vessel does not include vessels permanently attached 
to motor vehicles, such as trucks, railcars, barges or ships.
    Synthetic organic chemicals manufacturing industry means the 
industry that produces, as intermediates or final products, one or more 
of the chemicals listed in Sec.  60.489.
    Transfer rack means the collection of loading arms and loading 
hoses, at a single loading rack, that are used to fill

[[Page 43075]]

tank trucks and/or railcars with organic liquids.
    Volatile organic compounds or VOC means, for the purposes of this 
subpart, any reactive organic compounds as defined in Sec.  60.2.


Sec.  60.482-1b  Standards: General.

    (a) Each owner or operator subject to the provisions of this 
subpart shall demonstrate compliance with the requirements of 
Sec. Sec.  60.482-1b through 60.482-11b or Sec.  60.480b(e) for all 
equipment within 180 days of initial startup.
    (b) Compliance with Sec. Sec.  60.482-1b through 60.482-11b will be 
determined by review of records and reports, review of performance test 
results, and inspection using the methods and procedures specified in 
Sec.  60.485b.
    (c)(1) An owner or operator may request a determination of 
equivalence of a means of emission limitation to the requirements of 
Sec. Sec.  60.482-2b, 60.482-3b, 60.482-5b, 60.482-6b, 60.482-7b, 
60.482-8b, and 60.482-10b as provided in Sec.  60.484b.
    (2) If the Administrator makes a determination that a means of 
emission limitation is at least equivalent to the requirements of Sec.  
60.482-2b, Sec.  60.482-3b, Sec.  60.482-5b, Sec.  60.482-6b, Sec.  
60.482-7b, Sec.  60.482-8b, or Sec.  60.482-10b, an owner or operator 
shall comply with the requirements of that determination.
    (d) Equipment that is in vacuum service is excluded from the 
requirements of Sec. Sec.  60.482-2b through 60.482-11b if it is 
identified as required in Sec.  60.486b(e)(5).
    (e) Equipment that an owner or operator designates as being in VOC 
service less than 300 hr/yr is excluded from the requirements of 
Sec. Sec.  60.482-2b through 60.482-11b if it is identified as required 
in Sec.  60.486b(e)(6) and it meets any of the conditions specified in 
paragraphs (e)(1) through (3) of this section.
    (1) The equipment is in VOC service only during startup and 
shutdown, excluding startup and shutdown between batches of the same 
campaign for a batch process.
    (2) The equipment is in VOC service only during process 
malfunctions or other emergencies.
    (3) The equipment is backup equipment that is in VOC service only 
when the primary equipment is out of service.
    (f)(1) If a dedicated batch process unit operates less than 365 
days during a year, an owner or operator may monitor to detect leaks 
from pumps, valves, and open-ended valves or lines at the frequency 
specified in the following table instead of monitoring as specified in 
Sec. Sec.  60.482-2b, 60.482-7b, and 60.483.2a:

                                           Table 1 to Paragraph (f)(1)
----------------------------------------------------------------------------------------------------------------
                                                     Equivalent monitoring frequency time in use
 Operating time (percent of hours  -----------------------------------------------------------------------------
           during year)                    Monthly               Quarterly                 Semiannually
----------------------------------------------------------------------------------------------------------------
0 to <25..........................  Quarterly............  Annually.............  Annually.
25 to <50.........................  Quarterly............  Semiannually.........  Annually.
50 to <75.........................  Bimonthly............  Three quarters.......  Semiannually.
75 to 100.........................  Monthly..............  Quarterly............  Semiannually.
----------------------------------------------------------------------------------------------------------------

    (2) Pumps and valves that are shared among two or more batch 
process units that are subject to this subpart may be monitored at the 
frequencies specified in paragraph (f)(1) of this section, provided the 
operating time of all such process units is considered.
    (3) The monitoring frequencies specified in paragraph (f)(1) of 
this section are not requirements for monitoring at specific intervals 
and can be adjusted to accommodate process operations. An owner or 
operator may monitor at any time during the specified monitoring period 
(e.g., month, quarter, year), provided the monitoring is conducted at a 
reasonable interval after completion of the last monitoring campaign. 
Reasonable intervals are defined in paragraphs (f)(3)(i) through (iv) 
of this section.
    (i) When monitoring is conducted quarterly, monitoring events must 
be separated by at least 30 calendar days.
    (ii) When monitoring is conducted semiannually (i.e., once every 2 
quarters), monitoring events must be separated by at least 60 calendar 
days.
    (iii) When monitoring is conducted in 3 quarters per year, 
monitoring events must be separated by at least 90 calendar days.
    (iv) When monitoring is conducted annually, monitoring events must 
be separated by at least 120 calendar days.
    (g) The standards in Sec. Sec.  60.482-1b through 60.482-11b apply 
at all times, including periods of startup, shutdown, and malfunction. 
As provided in Sec.  60.11(f), this provision supersedes the exemptions 
for periods of startup, shutdown, and malfunction in the general 
provisions in subpart A of this part.


Sec.  60.482-2b  Standards: Pumps in light liquid service.

    (a)(1) Each pump in light liquid service shall be monitored monthly 
to detect leaks by the methods specified in Sec.  60.485b(b), except as 
provided in Sec.  60.482-1b(c) and (f) and paragraphs (d), (e), and (f) 
of this section. A pump that begins operation in light liquid service 
after the initial startup date for the process unit must be monitored 
for the first time within 30 days after the end of its startup period, 
except for a pump that replaces a leaking pump and except as provided 
in Sec.  60.482-1b(c) and paragraphs (d), (e), and (f) of this section.
    (2) Each pump in light liquid service shall be checked by visual 
inspection each calendar week for indications of liquids dripping from 
the pump seal, except as provided in Sec.  60.482-1b(f).
    (b)(1) The instrument reading that defines a leak is specified in 
paragraphs (b)(1)(i) and (ii) of this section.
    (i) 5,000 parts per million (ppm) or greater for pumps handling 
polymerizing monomers;
    (ii) 2,000 ppm or greater for all other pumps.
    (2) If there are indications of liquids dripping from the pump 
seal, the owner or operator shall follow the procedure specified in 
either paragraph (b)(2)(i) or (ii) of this section. This requirement 
does not apply to a pump that was monitored after a previous weekly 
inspection and the instrument reading was less than the concentration 
specified in paragraph (b)(1)(i) or (ii) of this section, whichever is 
applicable.
    (i) Monitor the pump within 5 days as specified in Sec.  
60.485b(b). A leak is detected if the instrument reading measured 
during monitoring indicates a leak as specified in paragraph (b)(1)(i) 
or (ii) of this section, whichever is applicable. The leak shall be 
repaired using the procedures in paragraph (c) of this section.
    (ii) Designate the visual indications of liquids dripping as a 
leak, and repair the leak using either the procedures in

[[Page 43076]]

paragraph (c) of this section or by eliminating the visual indications 
of liquids dripping.
    (c)(1) When a leak is detected, it shall be repaired as soon as 
practicable, but not later than 15 calendar days after it is detected, 
except as provided in Sec.  60.482-9b.
    (2) A first attempt at repair shall be made no later than 5 
calendar days after each leak is detected. First attempts at repair 
include, but are not limited to, the practices described in paragraphs 
(c)(2)(i) and (ii) of this section, where practicable.
    (i) Tightening the packing gland nuts;
    (ii) Ensuring that the seal flush is operating at design pressure 
and temperature.
    (d) Each pump equipped with a dual mechanical seal system that 
includes a barrier fluid system is exempt from the requirements of 
paragraph (a) of this section, provided the requirements specified in 
paragraphs (d)(1) through (6) of this section are met.
    (1) Each dual mechanical seal system is:
    (i) Operated with the barrier fluid at a pressure that is at all 
times greater than the pump stuffing box pressure; or
    (ii) Equipped with a barrier fluid degassing reservoir that is 
routed to a process or fuel gas system or connected by a closed vent 
system to a control device that complies with the requirements of Sec.  
60.482-10b; or
    (iii) Equipped with a system that purges the barrier fluid into a 
process stream with zero VOC emissions to the atmosphere.
    (2) The barrier fluid system is in heavy liquid service or is not 
in VOC service.
    (3) Each barrier fluid system is equipped with a sensor that will 
detect failure of the seal system, the barrier fluid system, or both.
    (4)(i) Each pump is checked by visual inspection, each calendar 
week, for indications of liquids dripping from the pump seals.
    (ii) If there are indications of liquids dripping from the pump 
seal at the time of the weekly inspection, the owner or operator shall 
follow the procedure specified in either paragraph (d)(4)(ii)(A) or (B) 
of this section prior to the next required inspection.
    (A) Monitor the pump within 5 days as specified in Sec.  60.485b(b) 
to determine if there is a leak of VOC in the barrier fluid. If an 
instrument reading of 2,000 ppm or greater is measured, a leak is 
detected.
    (B) Designate the visual indications of liquids dripping as a leak.
    (5)(i) Each sensor as described in paragraph (d)(3) is checked 
daily or is equipped with an audible alarm.
    (ii) The owner or operator determines, based on design 
considerations and operating experience, a criterion that indicates 
failure of the seal system, the barrier fluid system, or both.
    (iii) If the sensor indicates failure of the seal system, the 
barrier fluid system, or both, based on the criterion established in 
paragraph (d)(5)(ii) of this section, a leak is detected.
    (6)(i) When a leak is detected pursuant to paragraph (d)(4)(ii)(A) 
of this section, it shall be repaired as specified in paragraph (c) of 
this section.
    (ii) A leak detected pursuant to paragraph (d)(5)(iii) of this 
section shall be repaired within 15 days of detection by eliminating 
the conditions that activated the sensor.
    (iii) A designated leak pursuant to paragraph (d)(4)(ii)(B) of this 
section shall be repaired within 15 days of detection by eliminating 
visual indications of liquids dripping.
    (e) Any pump that is designated, as described in Sec.  
60.486b(e)(1) and (2), for no detectable emissions, as indicated by an 
instrument reading of less than 500 ppm above background, is exempt 
from the requirements of paragraphs (a), (c), and (d) of this section 
if the pump:
    (1) Has no externally actuated shaft penetrating the pump housing;
    (2) Is demonstrated to be operating with no detectable emissions as 
indicated by an instrument reading of less than 500 ppm above 
background as measured by the methods specified in Sec.  60.485b(c); 
and
    (3) Is tested for compliance with paragraph (e)(2) of this section 
initially upon designation, annually, and at other times requested by 
the Administrator.
    (f) If any pump is equipped with a closed vent system capable of 
capturing and transporting any leakage from the seal or seals to a 
process or to a fuel gas system or to a control device that complies 
with the requirements of Sec.  60.482-10b, it is exempt from paragraphs 
(a) through (e) of this section.
    (g) Any pump that is designated, as described in Sec.  
60.486b(f)(1), as an unsafe-to-monitor pump is exempt from the 
monitoring and inspection requirements of paragraphs (a) and (d)(4) 
through (6) of this section if:
    (1) The owner or operator of the pump demonstrates that the pump is 
unsafe-to-monitor because monitoring personnel would be exposed to an 
immediate danger as a consequence of complying with paragraph (a) of 
this section; and
    (2) The owner or operator of the pump has a written plan that 
requires monitoring of the pump as frequently as practicable during 
safe-to-monitor times, but not more frequently than the periodic 
monitoring schedule otherwise applicable, and repair of the equipment 
according to the procedures in paragraph (c) of this section if a leak 
is detected.
    (h) Any pump that is located within the boundary of an unmanned 
plant site is exempt from the weekly visual inspection requirement of 
paragraphs (a)(2) and (d)(4) of this section, and the daily 
requirements of paragraph (d)(5) of this section, provided that each 
pump is visually inspected as often as practicable and at least 
monthly.


Sec.  60.482-3b  Standards: Compressors.

    (a) Each compressor shall be equipped with a seal system that 
includes a barrier fluid system and that prevents leakage of VOC to the 
atmosphere, except as provided in Sec.  60.482-1b(c) and paragraphs 
(h), (i), and (j) of this section.
    (b) Each compressor seal system as required in paragraph (a) of 
this section shall be:
    (1) Operated with the barrier fluid at a pressure that is greater 
than the compressor stuffing box pressure; or
    (2) Equipped with a barrier fluid system degassing reservoir that 
is routed to a process or fuel gas system or connected by a closed vent 
system to a control device that complies with the requirements of Sec.  
60.482-10b; or
    (3) Equipped with a system that purges the barrier fluid into a 
process stream with zero VOC emissions to the atmosphere.
    (c) The barrier fluid system shall be in heavy liquid service or 
shall not be in VOC service.
    (d) Each barrier fluid system as described in paragraph (a) of this 
section shall be equipped with a sensor that will detect failure of the 
seal system, barrier fluid system, or both.
    (e)(1) Each sensor as required in paragraph (d) of this section 
shall be checked daily or shall be equipped with an audible alarm.
    (2) The owner or operator shall determine, based on design 
considerations and operating experience, a criterion that indicates 
failure of the seal system, the barrier fluid system, or both.
    (f) If the sensor indicates failure of the seal system, the barrier 
system, or both based on the criterion determined under paragraph 
(e)(2) of this section, a leak is detected.
    (g)(1) When a leak is detected, it shall be repaired as soon as 
practicable, but not later than 15 calendar days after it is detected, 
except as provided in Sec.  60.482-9b.

[[Page 43077]]

    (2) A first attempt at repair shall be made no later than 5 
calendar days after each leak is detected.
    (h) A compressor is exempt from the requirements of paragraphs (a) 
and (b) of this section, if it is equipped with a closed vent system to 
capture and transport leakage from the compressor drive shaft back to a 
process or fuel gas system or to a control device that complies with 
the requirements of Sec.  60.482-10b, except as provided in paragraph 
(i) of this section.
    (i) Any compressor that is designated, as described in Sec.  
60.486b(e)(1) and (2), for no detectable emissions, as indicated by an 
instrument reading of less than 500 ppm above background, is exempt 
from the requirements of paragraphs (a) through (h) of this section if 
the compressor:
    (1) Is demonstrated to be operating with no detectable emissions, 
as indicated by an instrument reading of less than 500 ppm above 
background, as measured by the methods specified in Sec.  60.485b(c); 
and
    (2) Is tested for compliance with paragraph (i)(1) of this section 
initially upon designation, annually, and at other times requested by 
the Administrator.
    (j) Any existing reciprocating compressor in a process unit which 
becomes an affected facility under provisions of Sec.  60.14 or Sec.  
60.15 is exempt from paragraphs (a) through (e) and (h) of this 
section, provided the owner or operator demonstrates that recasting the 
distance piece or replacing the compressor are the only options 
available to bring the compressor into compliance with the provisions 
of paragraphs (a) through (e) and (h) of this section.


Sec.  60.482-4b  Standards: Pressure relief devices in gas/vapor 
service.

    (a) Except during pressure releases, each pressure relief device in 
gas/vapor service shall be operated with no detectable emissions, as 
indicated by an instrument reading of less than 500 ppm above 
background, as determined by the methods specified in Sec.  60.485b(c).
    (b)(1) After each pressure release, the pressure relief device 
shall be returned to a condition of no detectable emissions, as 
indicated by an instrument reading of less than 500 ppm above 
background, as soon as practicable, but no later than 5 calendar days 
after the pressure release, except as provided in Sec.  60.482-9b.
    (2) No later than 5 calendar days after the pressure release, the 
pressure relief device shall be monitored to confirm the conditions of 
no detectable emissions, as indicated by an instrument reading of less 
than 500 ppm above background, by the methods specified in Sec.  
60.485b(c).
    (c) Any pressure relief device that is routed to a process or fuel 
gas system or equipped with a closed vent system capable of capturing 
and transporting leakage through the pressure relief device to a 
control device as described in Sec.  60.482-10b is exempted from the 
requirements of paragraphs (a) and (b) of this section.
    (d)(1) Any pressure relief device that is equipped with a rupture 
disk upstream of the pressure relief device is exempt from the 
requirements of paragraphs (a) and (b) of this section, provided the 
owner or operator complies with the requirements in paragraph (d)(2) of 
this section.
    (2) After each pressure release, a new rupture disk shall be 
installed upstream of the pressure relief device as soon as 
practicable, but no later than 5 calendar days after each pressure 
release, except as provided in Sec.  60.482-9b.


Sec.  60.482-5b  Standards: Sampling connection systems.

    (a) Each sampling connection system shall be equipped with a 
closed-purge, closed-loop, or closed-vent system, except as provided in 
Sec.  60.482-1b(c) and paragraph (c) of this section.
    (b) Each closed-purge, closed-loop, or closed-vent system as 
required in paragraph (a) of this section shall comply with the 
requirements specified in paragraphs (b)(1) through (4) of this 
section.
    (1) Gases displaced during filling of the sample container are not 
required to be collected or captured.
    (2) Containers that are part of a closed-purge system must be 
covered or closed when not being filled or emptied.
    (3) Gases remaining in the tubing or piping between the closed-
purge system valve(s) and sample container valve(s) after the valves 
are closed and the sample container is disconnected are not required to 
be collected or captured.
    (4) Each closed-purge, closed-loop, or closed-vent system shall be 
designed and operated to meet requirements in either paragraph 
(b)(4)(i), (ii), (iii), or (iv) of this section.
    (i) Return the purged process fluid directly to the process line.
    (ii) Collect and recycle the purged process fluid to a process.
    (iii) Capture and transport all the purged process fluid to a 
control device that complies with the requirements of Sec.  60.482-10b.
    (iv) Collect, store, and transport the purged process fluid to any 
of the following systems or facilities:
    (A) A waste management unit as defined in 40 CFR 63.111, if the 
waste management unit is subject to and operated in compliance with the 
provisions of 40 CFR part 63, subpart G, applicable to Group 1 
wastewater streams;
    (B) A treatment, storage, or disposal facility subject to 
regulation under 40 CFR part 262, 264, 265, or 266;
    (C) A facility permitted, licensed, or registered by a state to 
manage municipal or industrial solid waste, if the process fluids are 
not hazardous waste as defined in 40 CFR part 261;
    (D) A waste management unit subject to and operated in compliance 
with the treatment requirements of 40 CFR 61.348(a), provided all waste 
management units that collect, store, or transport the purged process 
fluid to the treatment unit are subject to and operated in compliance 
with the management requirements of 40 CFR 61.343 through 40 CFR 
61.347; or
    (E) A device used to burn off-specification used oil for energy 
recovery in accordance with 40 CFR part 279, subpart G, provided the 
purged process fluid is not hazardous waste as defined in 40 CFR part 
261.
    (c) In-situ sampling systems and sampling systems without purges 
are exempt from the requirements of paragraphs (a) and (b) of this 
section.


Sec.  60.482-6b  Standards: Open-ended valves or lines.

    (a)(1) Each open-ended valve or line shall be equipped with a cap, 
blind flange, plug, or a second valve, except as provided in Sec.  
60.482-1b(c) and paragraphs (d) and (e) of this section.
    (2) The cap, blind flange, plug, or second valve shall seal the 
open end at all times except during operations requiring process fluid 
flow through the open-ended valve or line.
    (b) Each open-ended valve or line equipped with a second valve 
shall be operated in a manner such that the valve on the process fluid 
end is closed before the second valve is closed.
    (c) When a double block-and-bleed system is being used, the bleed 
valve or line may remain open during operations that require venting 
the line between the block valves but shall comply with paragraph (a) 
of this section at all other times.
    (d) Open-ended valves or lines in an emergency shutdown system 
which are designed to open automatically in the event of a process 
upset are exempt from the requirements of paragraphs (a), (b), and (c) 
of this section.
    (e) Open-ended valves or lines containing materials which would 
autocatalytically polymerize or would present an explosion, serious 
overpressure, or other safety hazard if

[[Page 43078]]

capped or equipped with a double block and bleed system as specified in 
paragraphs (a) through (c) of this section are exempt from the 
requirements of paragraphs (a) through (c) of this section.


Sec.  60.482-7b  Standards: Valves in gas/vapor service and in light 
liquid service.

    (a)(1) Each valve shall be monitored monthly to detect leaks by the 
methods specified in Sec.  60.485b(b) and shall comply with paragraphs 
(b) through (e) of this section, except as provided in paragraphs (f), 
(g), and (h) of this section, Sec.  60.482-1b(c) and (f), and 
Sec. Sec.  60.483-1b and 60.483-2b.
    (2) A valve that begins operation in gas/vapor service or light 
liquid service after the initial startup date for the process unit must 
be monitored according to paragraphs (a)(2)(i) or (ii), except for a 
valve that replaces a leaking valve and except as provided in 
paragraphs (f), (g), and (h) of this section, Sec.  60.482-1b(c), and 
Sec. Sec.  60.483-1b and 60.483-2b.
    (i) Monitor the valve as in paragraph (a)(1) of this section. The 
valve must be monitored for the first time within 30 days after the end 
of its startup period to ensure proper installation.
    (ii) If the existing valves in the process unit are monitored in 
accordance with Sec.  60.483-1b or Sec.  60.483-2b, count the new valve 
as leaking when calculating the percentage of valves leaking as 
described in Sec.  60.483-2b(b)(5). If less than 2.0 percent of the 
valves are leaking for that process unit, the valve must be monitored 
for the first time during the next scheduled monitoring event for 
existing valves in the process unit or within 90 days, whichever comes 
first.
    (b) If an instrument reading of 100 ppm or greater is measured, a 
leak is detected.
    (c)(1)(i) Any valve for which a leak is not detected for 2 
successive months may be monitored the first month of every quarter, 
beginning with the next quarter, until a leak is detected.
    (ii) As an alternative to monitoring all of the valves in the first 
month of a quarter, an owner or operator may elect to subdivide the 
process unit into two or three subgroups of valves and monitor each 
subgroup in a different month during the quarter, provided each 
subgroup is monitored every 3 months. The owner or operator must keep 
records of the valves assigned to each subgroup.
    (2) If a leak is detected, the valve shall be monitored monthly 
until a leak is not detected for 2 successive months.
    (d)(1) When a leak is detected, it shall be repaired as soon as 
practicable, but no later than 15 calendar days after the leak is 
detected, except as provided in Sec.  60.482-9b.
    (2) A first attempt at repair shall be made no later than 5 
calendar days after each leak is detected.
    (e) First attempts at repair include, but are not limited to, the 
following best practices where practicable:
    (1) Tightening of bonnet bolts;
    (2) Replacement of bonnet bolts;
    (3) Tightening of packing gland nuts;
    (4) Injection of lubricant into lubricated packing.
    (f) Any valve that is designated, as described in Sec.  
60.486b(e)(2), for no detectable emissions, as indicated by an 
instrument reading of less than 100 ppm above background, is exempt 
from the requirements of paragraph (a) of this section if the valve:
    (1) Has no external actuating mechanism in contact with the process 
fluid,
    (2) Is operated with emissions less than 100 ppm above background 
as determined by the method specified in Sec.  60.485b(c), and
    (3) Is tested for compliance with paragraph (f)(2) of this section 
initially upon designation, annually, and at other times requested by 
the Administrator.
    (g) Any valve that is designated, as described in Sec.  
60.486b(f)(1), as an unsafe-to-monitor valve is exempt from the 
requirements of paragraph (a) of this section if:
    (1) The owner or operator of the valve demonstrates that the valve 
is unsafe to monitor because monitoring personnel would be exposed to 
an immediate danger as a consequence of complying with paragraph (a) of 
this section, and
    (2) The owner or operator of the valve adheres to a written plan 
that requires monitoring of the valve as frequently as practicable 
during safe-to-monitor times.
    (h) Any valve that is designated, as described in Sec.  
60.486b(f)(2), as a difficult-to-monitor valve is exempt from the 
requirements of paragraph (a) of this section if:
    (1) The owner or operator of the valve demonstrates that the valve 
cannot be monitored without elevating the monitoring personnel more 
than 2 meters above a support surface.
    (2) The process unit within which the valve is located either:
    (i) Becomes an affected facility through Sec.  60.14 or Sec.  60.15 
and was constructed on or before January 5, 1981; or
    (ii) Has less than 3.0 percent of its total number of valves 
designated as difficult-to-monitor by the owner or operator.
    (3) The owner or operator of the valve follows a written plan that 
requires monitoring of the valve at least once per calendar year.


Sec.  60.482-8b  Standards: Pumps, valves, and connectors in heavy 
liquid service and pressure relief devices in light liquid or heavy 
liquid service.

    (a) If evidence of a potential leak is found by visual, audible, 
olfactory, or any other detection method at pumps, valves, and 
connectors in heavy liquid service and pressure relief devices in light 
liquid or heavy liquid service, the owner or operator shall follow 
either one of the following procedures:
    (1) The owner or operator shall monitor the equipment within 5 days 
by the method specified in Sec.  60.485b(b) and shall comply with the 
requirements of paragraphs (b) through (d) of this section.
    (2) The owner or operator shall eliminate the visual, audible, 
olfactory, or other indication of a potential leak within 5 calendar 
days of detection.
    (b) If an instrument reading of 10,000 ppm or greater is measured, 
a leak is detected.
    (c)(1) When a leak is detected, it shall be repaired as soon as 
practicable, but not later than 15 calendar days after it is detected, 
except as provided in Sec.  60.482-9b.
    (2) The first attempt at repair shall be made no later than 5 
calendar days after each leak is detected.
    (d) First attempts at repair include, but are not limited to, the 
best practices described under Sec. Sec.  60.482-2b(c)(2) and 60.482-
7b(e).


Sec.  60.482-9b  Standards: Delay of repair.

    (a) Delay of repair of equipment for which leaks have been detected 
will be allowed if repair within 15 days is technically infeasible 
without a process unit shutdown. Repair of this equipment shall occur 
before the end of the next process unit shutdown. Monitoring to verify 
repair must occur within 15 days after startup of the process unit.
    (b) Delay of repair of equipment will be allowed for equipment 
which is isolated from the process and which does not remain in VOC 
service.
    (c) Delay of repair for valves and connectors will be allowed if:
    (1) The owner or operator demonstrates that emissions of purged 
material resulting from immediate repair are greater than the fugitive 
emissions likely to result from delay of repair, and
    (2) When repair procedures are effected, the purged material is 
collected and destroyed or recovered in a control device complying with 
Sec.  60.482-10b.
    (d) Delay of repair for pumps will be allowed if:

[[Page 43079]]

    (1) Repair requires the use of a dual mechanical seal system that 
includes a barrier fluid system, and
    (2) Repair is completed as soon as practicable, but not later than 
6 months after the leak was detected.
    (e) Delay of repair beyond a process unit shutdown will be allowed 
for a valve, if valve assembly replacement is necessary during the 
process unit shutdown, valve assembly supplies have been depleted, and 
valve assembly supplies had been sufficiently stocked before the 
supplies were depleted. Delay of repair beyond the next process unit 
shutdown will not be allowed unless the next process unit shutdown 
occurs sooner than 6 months after the first process unit shutdown.
    (f) When delay of repair is allowed for a leaking pump, valve, or 
connector that remains in service, the pump, valve, or connector may be 
considered to be repaired and no longer subject to delay of repair 
requirements if two consecutive monthly monitoring instrument readings 
are below the leak definition.


Sec.  60.482-10b  Standards: Closed vent systems and control devices.

    (a) Owners or operators of closed vent systems and control devices 
used to comply with provisions of this subpart shall comply with the 
provisions of this section.
    (b) Vapor recovery systems (for example, condensers and absorbers) 
shall be designed and operated to recover the VOC emissions vented to 
them with an efficiency of 95 percent or greater, or to an exit 
concentration of 20 parts per million by volume (ppmv), whichever is 
less stringent.
    (c) Enclosed combustion devices shall be designed and operated to 
reduce the VOC emissions vented to them with an efficiency of 95 
percent or greater, or to an exit concentration of 20 ppmv, on a dry 
basis, corrected to 3 percent oxygen, whichever is less stringent or to 
provide a minimum residence time of 0.75 seconds at a minimum 
temperature of 816 [deg]C.
    (d) Flares used to comply with this subpart shall comply with the 
requirements of Sec.  60.18.
    (e) Owners or operators of control devices used to comply with the 
provisions of this subpart shall monitor these control devices to 
ensure that they are operated and maintained in conformance with their 
designs.
    (f) Except as provided in paragraphs (i) through (k) of this 
section, each closed vent system shall be inspected according to the 
procedures and schedule specified in paragraphs (f)(1) through (3) of 
this section.
    (1) Conduct an initial inspection according to the procedures in 
Sec.  60.485b(b); and
    (2) Conduct annual inspections according to the procedures in Sec.  
60.485b(b).
    (3) Conduct annual visual inspections for visible, audible, or 
olfactory indications of leaks.
    (g) Leaks, as indicated by an instrument reading greater than 500 
ppmv above background or by visual inspections, shall be repaired as 
soon as practicable except as provided in paragraph (h) of this 
section.
    (1) A first attempt at repair shall be made no later than 5 
calendar days after the leak is detected.
    (2) Repair shall be completed no later than 15 calendar days after 
the leak is detected.
    (h) Delay of repair of a closed vent system for which leaks have 
been detected is allowed if the repair is technically infeasible 
without a process unit shutdown or if the owner or operator determines 
that emissions resulting from immediate repair would be greater than 
the fugitive emissions likely to result from delay of repair. Repair of 
such equipment shall be complete by the end of the next process unit 
shutdown.
    (i) If a vapor collection system or closed vent system is operated 
under a vacuum, it is exempt from the inspection requirements of 
paragraphs (f)(1) and (2) of this section.
    (j) Any parts of the closed vent system that are designated, as 
described in paragraph (l)(1) of this section, as unsafe to inspect are 
exempt from the inspection requirements of paragraphs (f)(1) and (2) of 
this section if they comply with the requirements specified in 
paragraphs (j)(1) and (2) of this section:
    (1) The owner or operator determines that the equipment is unsafe 
to inspect because inspecting personnel would be exposed to an imminent 
or potential danger as a consequence of complying with paragraphs 
(f)(1) and (2) of this section; and
    (2) The owner or operator has a written plan that requires 
inspection of the equipment as frequently as practicable during safe-
to-inspect times.
    (k) Any parts of the closed vent system that are designated, as 
described in paragraph (l)(2) of this section, as difficult to inspect 
are exempt from the inspection requirements of paragraphs (f)(1) and 
(2) of this section if they comply with the requirements specified in 
paragraphs (k)(1) through (3) of this section:
    (1) The owner or operator determines that the equipment cannot be 
inspected without elevating the inspecting personnel more than 2 meters 
above a support surface; and
    (2) The process unit within which the closed vent system is located 
becomes an affected facility through Sec. Sec.  60.14 or 60.15, or the 
owner or operator designates less than 3.0 percent of the total number 
of closed vent system equipment as difficult to inspect; and
    (3) The owner or operator has a written plan that requires 
inspection of the equipment at least once every 5 years. A closed vent 
system is exempt from inspection if it is operated under a vacuum.
    (l) The owner or operator shall record the information specified in 
paragraphs (l)(1) through (5) of this section.
    (1) Identification of all parts of the closed vent system that are 
designated as unsafe to inspect, an explanation of why the equipment is 
unsafe to inspect, and the plan for inspecting the equipment.
    (2) Identification of all parts of the closed vent system that are 
designated as difficult to inspect, an explanation of why the equipment 
is difficult to inspect, and the plan for inspecting the equipment.
    (3) For each inspection during which a leak is detected, a record 
of the information specified in Sec.  60.486b(c).
    (4) For each inspection conducted in accordance with Sec.  
60.485b(b) during which no leaks are detected, a record that the 
inspection was performed, the date of the inspection, and a statement 
that no leaks were detected.
    (5) For each visual inspection conducted in accordance with 
paragraph (f)(3) of this section during which no leaks are detected, a 
record that the inspection was performed, the date of the inspection, 
and a statement that no leaks were detected.
    (m) Closed vent systems and control devices used to comply with 
provisions of this subpart shall be operated at all times when 
emissions may be vented to them.


Sec.  60.482-11b  Standards: Connectors in gas/vapor service and in 
light liquid service.

    (a) The owner or operator shall initially monitor all connectors in 
the process unit for leaks by the later of either 12 months after the 
compliance date or 12 months after initial startup. If all connectors 
in the process unit have been monitored for leaks prior to the 
compliance date, no initial monitoring is required provided either no 
process changes have been made since the monitoring or the owner or 
operator can determine that the results of the monitoring, with or 
without adjustments, reliably demonstrate

[[Page 43080]]

compliance despite process changes. If required to monitor because of a 
process change, the owner or operator is required to monitor only those 
connectors involved in the process change.
    (b) Except as allowed in Sec.  60.482-1b(c), Sec.  60.482-10b, or 
as specified in paragraph (e) of this section, the owner or operator 
shall monitor all connectors in gas and vapor and light liquid service 
as specified in paragraphs (a) and (b)(3) of this section.
    (1) The connectors shall be monitored to detect leaks by the method 
specified in Sec.  60.485b(b) and, as applicable, Sec.  60.485b(c).
    (2) If an instrument reading greater than or equal to 500 ppm is 
measured, a leak is detected.
    (3) The owner or operator shall perform monitoring, subsequent to 
the initial monitoring required in paragraph (a) of this section, as 
specified in paragraphs (b)(3)(i) through (iii) of this section, and 
shall comply with the requirements of paragraphs (b)(3)(iv) and (v) of 
this section. The required period in which monitoring must be conducted 
shall be determined from paragraphs (b)(3)(i) through (iii) of this 
section using the monitoring results from the preceding monitoring 
period. The percent leaking connectors shall be calculated as specified 
in paragraph (c) of this section.
    (i) If the percent leaking connectors in the process unit was 
greater than or equal to 0.5 percent, then monitor within 12 months (1 
year).
    (ii) If the percent leaking connectors in the process unit was 
greater than or equal to 0.25 percent but less than 0.5 percent, then 
monitor within 4 years. An owner or operator may comply with the 
requirements of this paragraph by monitoring at least 40 percent of the 
connectors within 2 years of the start of the monitoring period, 
provided all connectors have been monitored by the end of the 4-year 
monitoring period.
    (iii) If the percent leaking connectors in the process unit was 
less than 0.25 percent, then monitor as provided in paragraph 
(b)(3)(iii)(A) of this section and either paragraph (b)(3)(iii)(B) or 
(C) of this section, as appropriate.
    (A) An owner or operator shall monitor at least 50 percent of the 
connectors within 4 years of the start of the monitoring period.
    (B) If the percent of leaking connectors calculated from the 
monitoring results in paragraph (b)(3)(iii)(A) of this section is 
greater than or equal to 0.35 percent of the monitored connectors, the 
owner or operator shall monitor as soon as practical, but within the 
next 6 months, all connectors that have not yet been monitored during 
the monitoring period. At the conclusion of monitoring, a new 
monitoring period shall be started pursuant to paragraph (b)(3) of this 
section, based on the percent of leaking connectors within the total 
monitored connectors.
    (C) If the percent of leaking connectors calculated from the 
monitoring results in paragraph (b)(3)(iii)(A) of this section is less 
than 0.35 percent of the monitored connectors, the owner or operator 
shall monitor all connectors that have not yet been monitored within 8 
years of the start of the monitoring period.
    (iv) If, during the monitoring conducted pursuant to paragraphs 
(b)(3)(i) through (iii) of this section, a connector is found to be 
leaking, it shall be re-monitored once within 90 days after repair to 
confirm that it is not leaking.
    (v) The owner or operator shall keep a record of the start date and 
end date of each monitoring period under this section for each process 
unit.
    (c) For use in determining the monitoring frequency, as specified 
in paragraphs (a) and (b)(3) of this section, the percent leaking 
connectors as used in paragraphs (a) and (b)(3) of this section shall 
be calculated by using the following equation:
Equation 1 to Paragraph (c)
%CL = CL/Ct * 100

Where:

%CL = Percent of leaking connectors as determined through 
periodic monitoring required in paragraphs (a) and (b)(3)(i) through 
(iii) of this section.
CL = Number of connectors measured at 500 ppm or greater, 
by the method specified in Sec.  60.485b(b).
Ct = Total number of monitored connectors in the process 
unit or affected facility.

    (d) When a leak is detected pursuant to paragraphs (a) and (b) of 
this section, it shall be repaired as soon as practicable, but not 
later than 15 calendar days after it is detected, except as provided in 
Sec.  60.482-9b. A first attempt at repair as defined in this subpart 
shall be made no later than 5 calendar days after the leak is detected.
    (e) Any connector that is designated, as described in Sec.  
60.486b(f)(1), as an unsafe-to-monitor connector is exempt from the 
requirements of paragraphs (a) and (b) of this section if:
    (1) The owner or operator of the connector demonstrates that the 
connector is unsafe-to-monitor because monitoring personnel would be 
exposed to an immediate danger as a consequence of complying with 
paragraphs (a) and (b) of this section; and
    (2) The owner or operator of the connector has a written plan that 
requires monitoring of the connector as frequently as practicable 
during safe-to-monitor times but not more frequently than the periodic 
monitoring schedule otherwise applicable, and repair of the equipment 
according to the procedures in paragraph (d) of this section if a leak 
is detected.
    (f)(1) Any connector that is inaccessible or that is ceramic or 
ceramic-lined (e.g., porcelain, glass, or glass-lined), is exempt from 
the monitoring requirements of paragraphs (a) and (b) of this section, 
from the leak repair requirements of paragraph (d) of this section, and 
from the recordkeeping and reporting requirements of Sec. Sec.  63.1038 
and 63.1039. An inaccessible connector is one that meets any of the 
provisions specified in paragraphs (f)(1)(i) through (vi) of this 
section, as applicable:
    (i) Buried;
    (ii) Insulated in a manner that prevents access to the connector by 
a monitor probe;
    (iii) Obstructed by equipment or piping that prevents access to the 
connector by a monitor probe;
    (iv) Unable to be reached from a wheeled scissor-lift or hydraulic-
type scaffold that would allow access to connectors up to 7.6 meters 
(25 feet) above the ground;
    (v) Inaccessible because it would require elevating the monitoring 
personnel more than 2 meters (7 feet) above a permanent support surface 
or would require the erection of scaffold; or
    (vi) Not able to be accessed at any time in a safe manner to 
perform monitoring. Unsafe access includes, but is not limited to, the 
use of a wheeled scissor-lift on unstable or uneven terrain, the use of 
a motorized man-lift basket in areas where an ignition potential 
exists, or access would require near proximity to hazards such as 
electrical lines, or would risk damage to equipment.
    (2) If any inaccessible, ceramic, or ceramic-lined connector is 
observed by visual, audible, olfactory, or other means to be leaking, 
the visual, audible, olfactory, or other indications of a leak to the 
atmosphere shall be eliminated as soon as practical.
    (g) Except for instrumentation systems and inaccessible, ceramic, 
or ceramic-lined connectors meeting the provisions of paragraph (f) of 
this section, identify the connectors subject to the requirements of 
this subpart. Connectors need not be individually identified if all

[[Page 43081]]

connectors in a designated area or length of pipe subject to the 
provisions of this subpart are identified as a group, and the number of 
connectors subject is indicated.


Sec.  60.483-1b  Alternative standards for valves--allowable percentage 
of valves leaking.

    (a) An owner or operator may elect to comply with an allowable 
percentage of valves leaking of equal to or less than 2.0 percent.
    (b) The following requirements shall be met if an owner or operator 
wishes to comply with an allowable percentage of valves leaking:
    (1) An owner or operator must notify the Administrator that the 
owner or operator has elected to comply with the allowable percentage 
of valves leaking before implementing this alternative standard, as 
specified in Sec.  60.487b(d).
    (2) A performance test as specified in paragraph (c) of this 
section shall be conducted initially upon designation, annually, and at 
other times requested by the Administrator.
    (3) If a valve leak is detected, it shall be repaired in accordance 
with Sec.  60.482-7b(d) and (e).
    (c) Performance tests shall be conducted in the following manner:
    (1) All valves in gas/vapor and light liquid service within the 
affected facility shall be monitored within 1 week by the methods 
specified in Sec.  60.485b(b).
    (2) If an instrument reading of 500 ppm or greater is measured, a 
leak is detected.
    (3) The leak percentage shall be determined by dividing the number 
of valves for which leaks are detected by the number of valves in gas/
vapor and light liquid service within the affected facility.
    (d) Owners and operators who elect to comply with this alternative 
standard shall not have an affected facility with a leak percentage 
greater than 2.0 percent, determined as described in Sec.  60.485b(h).


Sec.  60.483-2b  Alternative standards for valves--skip period leak 
detection and repair.

    (a)(1) An owner or operator may elect to comply with one of the 
alternative work practices specified in paragraphs (b)(2) and (3) of 
this section.
    (2) An owner or operator must notify the Administrator before 
implementing one of the alternative work practices, as specified in 
Sec.  60.487a(d).
    (b)(1) An owner or operator shall comply initially with the 
requirements for valves in gas/vapor service and valves in light liquid 
service, as described in Sec.  60.482-7b.
    (2) After 2 consecutive quarterly leak detection periods with the 
percent of valves leaking equal to or less than 2.0, an owner or 
operator may begin to skip 1 of the quarterly leak detection periods 
for the valves in gas/vapor and light liquid service.
    (3) After 5 consecutive quarterly leak detection periods with the 
percent of valves leaking equal to or less than 2.0, an owner or 
operator may begin to skip 3 of the quarterly leak detection periods 
for the valves in gas/vapor and light liquid service.
    (4) If the percent of valves leaking is greater than 2.0, the owner 
or operator shall comply with the requirements as described in Sec.  
60.482-7b but can again elect to use this section.
    (5) The percent of valves leaking shall be determined as described 
in Sec.  60.485b(h).
    (6) An owner or operator must keep a record of the percent of 
valves found leaking during each leak detection period.
    (7) A valve that begins operation in gas/vapor service or light 
liquid service after the initial startup date for a process unit 
following one of the alternative standards in this section must be 
monitored in accordance with Sec.  60.482-7b(a)(2)(i) or (ii) before 
the provisions of this section can be applied to that valve.


Sec.  60.484b  Equivalence of means of emission limitation.

    (a) Each owner or operator subject to the provisions of this 
subpart may apply to the Administrator for determination of equivalence 
for any means of emission limitation that achieves a reduction in 
emissions of VOC at least equivalent to the reduction in emissions of 
VOC achieved by the controls required in this subpart.
    (b) Determination of equivalence to the equipment, design, and 
operational requirements of this subpart will be evaluated by the 
following guidelines:
    (1) Each owner or operator applying for an equivalence 
determination shall be responsible for collecting and verifying test 
data to demonstrate equivalence of means of emission limitation.
    (2) The Administrator will compare test data for demonstrating 
equivalence of the means of emission limitation to test data for the 
equipment, design, and operational requirements.
    (3) The Administrator may condition the approval of equivalence on 
requirements that may be necessary to assure operation and maintenance 
to achieve the same emission reduction as the equipment, design, and 
operational requirements.
    (c) Determination of equivalence to the required work practices in 
this subpart will be evaluated by the following guidelines:
    (1) Each owner or operator applying for a determination of 
equivalence shall be responsible for collecting and verifying test data 
to demonstrate equivalence of an equivalent means of emission 
limitation.
    (2) For each affected facility for which a determination of 
equivalence is requested, the emission reduction achieved by the 
required work practice shall be demonstrated.
    (3) For each affected facility, for which a determination of 
equivalence is requested, the emission reduction achieved by the 
equivalent means of emission limitation shall be demonstrated.
    (4) Each owner or operator applying for a determination of 
equivalence shall commit in writing to work practice(s) that provide 
for emission reductions equal to or greater than the emission 
reductions achieved by the required work practice.
    (5) The Administrator will compare the demonstrated emission 
reduction for the equivalent means of emission limitation to the 
demonstrated emission reduction for the required work practices and 
will consider the commitment in paragraph (c)(4) of this section.
    (6) The Administrator may condition the approval of equivalence on 
requirements that may be necessary to assure operation and maintenance 
to achieve the same emission reduction as the required work practice.
    (d) An owner or operator may offer a unique approach to demonstrate 
the equivalence of any equivalent means of emission limitation.
    (e)(1) After a request for determination of equivalence is 
received, the Administrator will publish a notice in the Federal 
Register and provide the opportunity for public hearing if the 
Administrator judges that the request may be approved.
    (2) After notice and opportunity for public hearing, the 
Administrator will determine the equivalence of a means of emission 
limitation and will publish the determination in the Federal Register.
    (3) Any equivalent means of emission limitations approved under 
this section shall constitute a required work practice, equipment, 
design, or operational standard within the meaning of section 111(h)(1) 
of the CAA.
    (f)(1) Manufacturers of equipment used to control equipment leaks 
of VOC may apply to the Administrator for determination of equivalence 
for any

[[Page 43082]]

equivalent means of emission limitation that achieves a reduction in 
emissions of VOC achieved by the equipment, design, and operational 
requirements of this subpart.
    (2) The Administrator will make an equivalence determination 
according to the provisions of paragraphs (b) through (e) of this 
section.


Sec.  60.485b  Test methods and procedures.

    (a) In conducting the performance tests required in Sec.  60.8, the 
owner or operator shall use as reference methods and procedures the 
test methods in appendix A to this part or other methods and procedures 
as specified in this section, except as provided in Sec.  60.8(b).
    (b) The owner or operator shall determine compliance with the 
standards in Sec. Sec.  60.482-1b through 60.482-11b, 60.483a, and 
60.484b as follows:
    (1) Method 21 of appendix A-7 to this part shall be used to 
determine the presence of leaking sources. The instrument shall be 
calibrated before use each day of its use by the procedures specified 
in Method 21. The following calibration gases shall be used:
    (i) Zero air (less than 10 ppm of hydrocarbon in air); and
    (ii) A mixture of methane or n-hexane and air at a concentration no 
more than 2,000 ppm greater than the leak definition concentration of 
the equipment monitored. If the monitoring instrument's design allows 
for multiple calibration scales, then the lower scale shall be 
calibrated with a calibration gas that is no higher than 2,000 ppm 
above the concentration specified as a leak, and the highest scale 
shall be calibrated with a calibration gas that is approximately equal 
to 10,000 ppm. If only one scale on an instrument will be used during 
monitoring, the owner or operator need not calibrate the scales that 
will not be used during that day's monitoring.
    (2) A calibration drift assessment shall be performed, at a 
minimum, at the end of each monitoring day. Check the instrument using 
the same calibration gas(es) that were used to calibrate the instrument 
before use. Follow the procedures specified in Method 21 of appendix A-
7 to this part, section 10.1, except do not adjust the meter readout to 
correspond to the calibration gas value. Record the instrument reading 
for each scale used as specified in Sec.  60.486b(e)(8). Divide the 
arithmetic difference of the initial and post-test calibration response 
by the corresponding calibration gas value for each scale and multiply 
by 100 to express the calibration drift as a percentage.
    (i) If a calibration drift assessment shows a negative drift of 
more than 10 percent, then all equipment with instrument readings 
between the appropriate leak definition and the leak definition 
multiplied by (100 minus the percent of negative drift/divided by 100) 
that was monitored since the last calibration must be re-monitored.
    (ii) If any calibration drift assessment shows a positive drift of 
more than 10 percent from the initial calibration value, then, at the 
owner/operator's discretion, all equipment with instrument readings 
above the appropriate leak definition and below the leak definition 
multiplied by (100 plus the percent of positive drift/divided by 100) 
monitored since the last calibration may be re-monitored.
    (c) The owner or operator shall determine compliance with the no-
detectable-emission standards in Sec. Sec.  60.482-2b(e), 60.482-3b(i), 
60.482-4b, 60.482-7b(f), and 60.482-10b(e) as follows:
    (1) The requirements of paragraph (b) shall apply.
    (2) Method 21 of appendix A-7 to this part shall be used to 
determine the background level. All potential leak interfaces shall be 
traversed as close to the interface as possible. The arithmetic 
difference between the maximum concentration indicated by the 
instrument and the background level is compared with 500 ppm for 
determining compliance.
    (d) The owner or operator shall test each piece of equipment unless 
they demonstrate that a process unit is not in VOC service, i.e., that 
the VOC content would never be reasonably expected to exceed 10 percent 
by weight. For purposes of this demonstration, the following methods 
and procedures shall be used:
    (1) Procedures that conform to the general methods in ASTM E168-16 
(Reapproved 2023), E169-16 (Reapproved 2022), or E260-96 (Reapproved 
2019) (incorporated by reference, see Sec.  60.17) shall be used to 
determine the percent VOC content in the process fluid that is 
contained in or contacts a piece of equipment.
    (2) Organic compounds that are considered by the Administrator to 
have negligible photochemical reactivity may be excluded from the total 
quantity of organic compounds in determining the VOC content of the 
process fluid.
    (3) Engineering judgment may be used to estimate the VOC content, 
if a piece of equipment had not been shown previously to be in service. 
If the Administrator disagrees with the judgment, paragraphs (d)(1) and 
(2) of this section shall be used to resolve the disagreement.
    (e) The owner or operator shall demonstrate that a piece of 
equipment is in light liquid service by showing that all the following 
conditions apply:
    (1) The vapor pressure of one or more of the organic components is 
greater than 0.3 kPa at 20 [deg]C (1.2 in. H2O at 68 
[deg]F). Standard reference texts or ASTM D2879-23 (incorporated by 
reference, see Sec.  60.17) shall be used to determine the vapor 
pressures.
    (2) The total concentration of the pure organic components having a 
vapor pressure greater than 0.3 kPa at 20 [deg]C (1.2 in. 
H2O at 68 [deg]F) is equal to or greater than 20 percent by 
weight.
    (3) The fluid is a liquid at operating conditions.
    (f) Samples used in conjunction with paragraphs (d), (e), and (g) 
of this section shall be representative of the process fluid that is 
contained in or contacts the equipment or the gas being combusted in 
the flare.
    (g) The owner or operator shall determine compliance with the 
standards of flares as follows:
    (1) Method 22 of appendix A-7 to this part shall be used to 
determine visible emissions.
    (2) A thermocouple or any other equivalent device shall be used to 
monitor the presence of a pilot flame in the flare.
    (3) The maximum permitted velocity for air assisted flares shall be 
computed using the following equation:
Equation 1 to Paragraph (g)(3)
Vmax = K1 + K2HT
Where:

Vmax = Maximum permitted velocity, m/sec (ft/sec).
HT = Net heating value of the gas being combusted, MJ/scm 
(Btu/scf).
K1 = 8.706 m/sec (metric units) = 28.56 ft/sec (English 
units).
K2 = 0.7084 m\4\/(MJ-sec) (metric units) = 0.087 ft\4\/
(Btu-sec) (English units).

    (4) The net heating value (HT) of the gas being combusted in a 
flare shall be computed using the following equation:
Equation 2 to Paragraph (g)(4)

[[Page 43083]]

[GRAPHIC] [TIFF OMITTED] TR16MY24.025

Where:

K = Conversion constant, 1.740 x 10-7 (g-mole)(MJ)/(ppm-
scm-kcal) (metric units) = 4.674 x 10-6 [(g-mole)(Btu)/
(ppm-scf-kcal)] (English units).
Ci = Concentration of sample component ``i,'' ppm
Hi = net heat of combustion of sample component ``i'' at 
25 [deg]C and 760 mm Hg (77 [deg]F and 14.7 psi), kcal/g-mole.

    (5) Method 18 of appendix A-6 to this part and ASTM D1945-14 
(Reapproved 2019) (incorporated by reference, see Sec.  60.17) shall be 
used to determine the concentration of sample component ``i.'' ASTM 
D6420-18 (incorporated by reference, see Sec.  [thinsp]60.17) may be 
used in lieu of Method 18, under the conditions specified in paragraphs 
(g)(5)(i) through (iii) of this section.
    (i) If the target compounds are all known and are all listed in 
Section 1.1 of ASTM D6420-18 as measurable.
    (ii) ASTM D6420-18 may not be used for methane and ethane.
    (iii) ASTM D6420-18 may not be used as a total VOC method.
    (6) ASTM D240-19 or D4809-18 (incorporated by reference, see Sec.  
60.17) shall be used to determine the net heat of combustion of 
component ``i'' if published values are not available or cannot be 
calculated.
    (7) Method 2, 2A, 2C, or 2D of appendix A-7 to this part, as 
appropriate, shall be used to determine the actual exit velocity of a 
flare. If needed, the unobstructed (free) cross-sectional area of the 
flare tip shall be used.
    (h) The owner or operator shall determine compliance with Sec.  
60.483-1b or Sec.  60.483-2b as follows:
    (1) The percent of valves leaking shall be determined using the 
following equation:
Equation 3 to Paragraph (h)(1)
%VL = (VL/VT) * 100

Where:

%VL = Percent leaking valves.
VL = Number of valves found leaking.
VT = The sum of the total number of valves monitored.

    (2) The total number of valves monitored shall include difficult-
to-monitor and unsafe-to-monitor valves only during the monitoring 
period in which those valves are monitored.
    (3) The number of valves leaking shall include valves for which 
repair has been delayed.
    (4) Any new valve that is not monitored within 30 days of being 
placed in service shall be included in the number of valves leaking and 
the total number of valves monitored for the monitoring period in which 
the valve is placed in service.
    (5) If the process unit has been subdivided in accordance with 
Sec.  60.482-7b(c)(1)(ii), the sum of valves found leaking during a 
monitoring period includes all subgroups.
    (6) The total number of valves monitored does not include a valve 
monitored to verify repair.


Sec.  60.486b  Recordkeeping requirements.

    (a)(1) Each owner or operator subject to the provisions of this 
subpart shall comply with the recordkeeping requirements of this 
section.
    (2) An owner or operator of more than one affected facility subject 
to the provisions of this subpart may comply with the recordkeeping 
requirements for these facilities in one recordkeeping system if the 
system identifies each record by each facility.
    (3) The owner or operator shall record the information specified in 
paragraphs (a)(3)(i) through (v) of this section for each monitoring 
event required by Sec. Sec.  60.482-2b, 60.482-3b, 60.482-7b, 60.482-
8b, 60.482-11b, and 60.483-2b.
    (i) Monitoring instrument identification.
    (ii) Operator identification.
    (iii) Equipment identification.
    (iv) Date of monitoring.
    (v) Instrument reading.
    (b) When each leak is detected as specified in Sec. Sec.  60.482-
2b, 60.482-3b, 60.482-7b, 60.482-8b, 60.482-11b, and 60.483-2b, the 
following requirements apply:
    (1) A weatherproof and readily visible identification, marked with 
the equipment identification number, shall be attached to the leaking 
equipment.
    (2) The identification on a valve may be removed after it has been 
monitored for 2 successive months as specified in Sec.  60.482-7b(c) 
and no leak has been detected during those 2 months.
    (3) The identification on a connector may be removed after it has 
been monitored as specified in Sec.  60.482-11b(b)(3)(iv) and no leak 
has been detected during that monitoring.
    (4) The identification on equipment, except on a valve or 
connector, may be removed after it has been repaired.
    (c) When each leak is detected as specified in Sec. Sec.  60.482-
2b, 60.482-3b, 60.482-7b, 60.482-8b, 60.482-11b, and 60.483-2b, the 
following information shall be recorded in a log and shall be kept for 
2 years in a readily accessible location:
    (1) The instrument and operator identification numbers and the 
equipment identification number, except when indications of liquids 
dripping from a pump are designated as a leak.
    (2) The date the leak was detected and the dates of each attempt to 
repair the leak.
    (3) Repair methods applied in each attempt to repair the leak.
    (4) Maximum instrument reading measured by Method 21 of appendix A-
7 of this part at the time the leak is successfully repaired or 
determined to be nonrepairable, except when a pump is repaired by 
eliminating indications of liquids dripping.
    (5) ``Repair delayed'' and the reason for the delay if a leak is 
not repaired within 15 calendar days after discovery of the leak.
    (6) The signature of the owner or operator (or designate) whose 
decision it was that repair could not be effected without a process 
shutdown.
    (7) The expected date of successful repair of the leak if a leak is 
not repaired within 15 days.
    (8) Dates of process unit shutdowns that occur while the equipment 
is unrepaired.
    (9) The date of successful repair of the leak.
    (d) The following information pertaining to the design requirements 
for closed vent systems and control devices described in Sec.  60.482-
10b shall be recorded and kept in a readily accessible location:
    (1) Detailed schematics, design specifications, and piping and 
instrumentation diagrams.
    (2) The dates and descriptions of any changes in the design 
specifications.
    (3) A description of the parameter or parameters monitored, as 
required in Sec.  60.482-10b(e), to ensure that control devices are 
operated and maintained in conformance with their design and an 
explanation of why that parameter (or parameters) was selected for the 
monitoring.
    (4) Periods when the closed vent systems and control devices 
required in Sec. Sec.  60.482-2b, 60.482-3b, 60.482-4b, and 60.482-5b 
are not operated as designed, including periods when a flare pilot 
light does not have a flame.
    (5) Dates of startups and shutdowns of the closed vent systems and 
control devices required in Sec. Sec.  60.482-2b, 60.482-3b, 60.482-4b, 
and 60.482-5b.

[[Page 43084]]

    (e) The following information pertaining to all equipment subject 
to the requirements in Sec. Sec.  60.482-1b to 60.482-11b shall be 
recorded in a log that is kept in a readily accessible location:
    (1) A list of identification numbers for equipment subject to the 
requirements of this subpart.
    (2)(i) A list of identification numbers for equipment that are 
designated for no detectable emissions under the provisions of 
Sec. Sec.  60.482-2b(e), 60.482-3b(i), and 60.482-7b(f).
    (ii) The designation of equipment as subject to the requirements of 
Sec.  60.482-2b(e), Sec.  60.482-3b(i), or Sec.  60.482-7b(f) shall be 
signed by the owner or operator. Alternatively, the owner or operator 
may establish a mechanism with their permitting authority that 
satisfies this requirement.
    (3) A list of equipment identification numbers for pressure relief 
devices required to comply with Sec.  60.482-4b.
    (4)(i) The dates of each compliance test as required in Sec. Sec.  
60.482-2b(e), 60.482-3b(i), 60.482-4b, and 60.482-7b(f).
    (ii) The background level measured during each compliance test.
    (iii) The maximum instrument reading measured at the equipment 
during each compliance test.
    (5) A list of identification numbers for equipment in vacuum 
service.
    (6) A list of identification numbers for equipment that the owner 
or operator designates as operating in VOC service less than 300 hr/yr 
in accordance with Sec.  60.482-1b(e), a description of the conditions 
under which the equipment is in VOC service, and rationale supporting 
the designation that it is in VOC service less than 300 hr/yr.
    (7) The date and results of the weekly visual inspection for 
indications of liquids dripping from pumps in light liquid service.
    (8) Records of the information specified in paragraphs (e)(8)(i) 
through (vi) of this section for monitoring instrument calibrations 
conducted according to sections 8.1.2 and 10 of Method 21 of appendix 
A-7 of this part and Sec.  60.485b(b).
    (i) Date of calibration and initials of operator performing the 
calibration.
    (ii) Calibration gas cylinder identification, certification date, 
and certified concentration.
    (iii) Instrument scale(s) used.
    (iv) A description of any corrective action taken if the meter 
readout could not be adjusted to correspond to the calibration gas 
value in accordance with section 10.1 of Method 21 of appendix A-7 of 
this part.
    (v) Results of each calibration drift assessment required by Sec.  
60.485b(b)(2) (i.e., instrument reading for calibration at end of 
monitoring day and the calculated percent difference from the initial 
calibration value).
    (vi) If an owner or operator makes their own calibration gas, a 
description of the procedure used.
    (9) The connector monitoring schedule for each process unit as 
specified in Sec.  60.482-11b(b)(3)(v).
    (10) Records of each release from a pressure relief device subject 
to Sec.  60.482-4b.
    (f) The following information pertaining to all valves subject to 
the requirements of Sec.  60.482-7b(g) and (h), all pumps subject to 
the requirements of Sec.  60.482-2b(g), and all connectors subject to 
the requirements of Sec.  60.482-11b(e) shall be recorded in a log that 
is kept in a readily accessible location:
    (1) A list of identification numbers for valves, pumps, and 
connectors that are designated as unsafe-to-monitor, an explanation for 
each valve, pump, or connector stating why the valve, pump, or 
connector is unsafe-to-monitor, and the plan for monitoring each valve, 
pump, or connector.
    (2) A list of identification numbers for valves that are designated 
as difficult-to-monitor, an explanation for each valve stating why the 
valve is difficult-to-monitor, and the schedule for monitoring each 
valve.
    (g) The following information shall be recorded for valves 
complying with Sec.  60.483-2b:
    (1) A schedule of monitoring.
    (2) The percent of valves found leaking during each monitoring 
period.
    (h) The following information shall be recorded in a log that is 
kept in a readily accessible location:
    (1) Design criterion required in Sec. Sec.  60.482-2b(d)(5) and 
60.482-3b(e)(2) and explanation of the design criterion; and
    (2) Any changes to this criterion and the reasons for the changes.
    (i) The following information shall be recorded in a log that is 
kept in a readily accessible location for use in determining exemptions 
as provided in Sec.  60.480b(d):
    (1) An analysis demonstrating the design capacity of the affected 
facility,
    (2) A statement listing the feed or raw materials and products from 
the affected facilities and an analysis demonstrating whether these 
chemicals are heavy liquids or beverage alcohol, and
    (3) An analysis demonstrating that equipment is not in VOC service.
    (j) Information and data used to demonstrate that a piece of 
equipment is not in VOC service shall be recorded in a log that is kept 
in a readily accessible location.
    (k) The provisions of Sec.  60.7(b) and (d) do not apply to 
affected facilities subject to this subpart.
    (l) Any records required to be maintained by this subpart that are 
submitted electronically via the EPA's Compliance and Emissions Data 
Reporting Interface (CEDRI) may be maintained in electronic format. 
This ability to maintain electronic copies does not affect the 
requirement for facilities to make records, data, and reports available 
upon request to a delegated air agency or the EPA as part of an on-site 
compliance evaluation.


Sec.  60.487b  Reporting requirements.

    (a) Each owner or operator subject to the provisions of this 
subpart shall submit semiannual reports to the Administrator beginning 
6 months after the initial startup date. Beginning on July 15, 2024, or 
once the report template for this subpart has been available on the 
CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 year, whichever date is later, submit all subsequent 
reports using the appropriate electronic report template on the CEDRI 
website for this subpart and following the procedure specified in 
paragraph (g) of this section. The date report templates become 
available will be listed on the CEDRI website. Unless the Administrator 
or delegated state agency or other authority has approved a different 
schedule for submission of reports, the report must be submitted by the 
deadline specified in this subpart, regardless of the method in which 
the report is submitted. All semiannual reports must include the 
following general information: company name, address (including 
county), and beginning and ending dates of the reporting period.
    (b) The initial semiannual report to the Administrator shall 
include the following information:
    (1) Process unit identification.
    (2) Number of valves subject to the requirements of Sec.  60.482-
7b, excluding those valves designated for no detectable emissions under 
the provisions of Sec.  60.482-7b(f).
    (3) Number of pumps subject to the requirements of Sec.  60.482-2b, 
excluding those pumps designated for no detectable emissions under the 
provisions of Sec.  60.482-2b(e) and those pumps complying with Sec.  
60.482-2b(f).
    (4) Number of compressors subject to the requirements of Sec.  
60.482-3b, excluding those compressors designated for no detectable 
emissions under the provisions of Sec.  60.482-3b(i) and those 
compressors complying with Sec.  60.482-3b(h).

[[Page 43085]]

    (5) Number of connectors subject to the requirements of Sec.  
60.482-11b.
    (c) All semiannual reports to the Administrator shall include the 
following information, summarized from the information in Sec.  
60.486b:
    (1) Process unit identification.
    (2) For each month during the semiannual reporting period,
    (i) Number of valves for which leaks were detected as described in 
Sec.  60.482-7b(b) or Sec.  60.483-2b,
    (ii) Number of valves for which leaks were not repaired as required 
in Sec.  60.482-7b(d)(1),
    (iii) Number of pumps for which leaks were detected as described in 
Sec.  60.482-2b(b), (d)(4)(ii)(A) or (B), or (d)(5)(iii),
    (iv) Number of pumps for which leaks were not repaired as required 
in Sec.  60.482-2b(c)(1) and (d)(6),
    (v) Number of compressors for which leaks were detected as 
described in Sec.  60.482-3b(f),
    (vi) Number of compressors for which leaks were not repaired as 
required in Sec.  60.482-3b(g)(1),
    (vii) Number of connectors for which leaks were detected as 
described in Sec.  60.482-11b(b)
    (viii) Number of connectors for which leaks were not repaired as 
required in Sec.  60.482-11b(d), and
    (ix)-(x) [Reserved]
    (xi) The facts that explain each delay of repair and, where 
appropriate, why a process unit shutdown was technically infeasible.
    (3) Dates of process unit shutdowns which occurred within the 
semiannual reporting period.
    (4) Revisions to items reported according to paragraph (b) of this 
section if changes have occurred since the initial report or subsequent 
revisions to the initial report.
    (d) An owner or operator electing to comply with the provisions of 
Sec. Sec.  60.483-1b or 60.483-2b shall notify the Administrator of the 
alternative standard selected 90 days before implementing either of the 
provisions.
    (e) An owner or operator shall report the results of all 
performance tests in accordance with Sec.  60.8. The provisions of 
Sec.  60.8(d) do not apply to affected facilities subject to the 
provisions of this subpart except that an owner or operator must notify 
the Administrator of the schedule for the initial performance tests at 
least 30 days before the initial performance tests.
    (f) The requirements of paragraphs (a) through (c) of this section 
remain in force until and unless EPA, in delegating enforcement 
authority to a state under section 111(c) of the CAA, approves 
reporting requirements or an alternative means of compliance 
surveillance adopted by such state. In that event, affected sources 
within the state will be relieved of the obligation to comply with the 
requirements of paragraphs (a) through (c) of this section, provided 
that they comply with the requirements established by the state. The 
EPA will not approve a waiver of electronic reporting to the EPA in 
delegating enforcement authority. Thus, electronic reporting to the EPA 
cannot be waived, and as such, the provisions of this paragraph cannot 
be used to relieve owners or operators of affected facilities of the 
requirement to submit the electronic reports required in this section 
to the EPA.
    (g) If you are required to submit notifications or reports 
following the procedure specified in this paragraph (g), you must 
submit notifications or reports to the EPA via CEDRI, which can be 
accessed through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/). The EPA will make all the information submitted through 
CEDRI available to the public without further notice to you. Do not use 
CEDRI to submit information you claim as CBI. Although we do not expect 
persons to assert a claim of CBI, if you wish to assert a CBI claim for 
some of the information in the report or notification, you must submit 
a complete file in the format specified in this subpart, including 
information claimed to be CBI, to the EPA following the procedures in 
paragraphs (g)(1) and (2) of this section. Clearly mark the part or all 
of the information that you claim to be CBI. Information not marked as 
CBI may be authorized for public release without prior notice. 
Information marked as CBI will not be disclosed except in accordance 
with procedures set forth in 40 CFR part 2. All CBI claims must be 
asserted at the time of submission. Anything submitted using CEDRI 
cannot later be claimed CBI. Furthermore, under CAA section 114(c), 
emissions data is not entitled to confidential treatment, and the EPA 
is required to make emissions data available to the public. Thus, 
emissions data will not be protected as CBI and will be made publicly 
available. You must submit the same file submitted to the CBI office 
with the CBI omitted to the EPA via the EPA's CDX as described earlier 
in this paragraph (g).
    (1) The preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
[email protected], and as described above, should include clear CBI 
markings. ERT files should be flagged to the attention of the Group 
Leader, Measurement Policy Group; all other files should be flagged to 
the attention of the SOCMI NSPS Sector Lead. If assistance is needed 
with submitting large electronic files that exceed the file size limit 
for email attachments, and if you do not have your own file sharing 
service, please email [email protected] to request a file transfer link.
    (2) If you cannot transmit the file electronically, you may send 
CBI information through the postal service to the following address: 
OAQPS Document Control Officer (C404-02), OAQPS, U.S. Environmental 
Protection Agency, 109 T.W. Alexander Drive, P.O. Box 12055, Research 
Triangle Park, North Carolina 27711. ERT files should be sent to the 
attention of the Group Leader, Measurement Policy Group, and all other 
files should be sent to the attention of the SOCMI NSPS Sector Lead. 
The mailed CBI material should be double wrapped and clearly marked. 
Any CBI markings should not show through the outer envelope.
    (h) If you are required to electronically submit notifications or 
reports through CEDRI in the EPA's CDX, you may assert a claim of EPA 
system outage for failure to timely comply with that reporting 
requirement. To assert a claim of EPA system outage, you must meet the 
requirements outlined in paragraphs (h)(1) through (7) of this section.
    (1) You must have been or will be precluded from accessing CEDRI 
and submitting a required report within the time prescribed due to an 
outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (5) You must provide to the Administrator a written description 
identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and

[[Page 43086]]

    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (i) If you are required to electronically submit notifications or 
reports through CEDRI in the EPA's CDX, you may assert a claim of force 
majeure for failure to timely comply with that reporting requirement. 
To assert a claim of force majeure, you must meet the requirements 
outlined in paragraphs (i)(1) through (5) of this section.
    (1) You may submit a claim if a force majeure event is about to 
occur, occurs, or has occurred or there are lingering effects from such 
an event within the period of time beginning five business days prior 
to the date the submission is due. For the purposes of this section, a 
force majeure event is defined as an event that will be or has been 
caused by circumstances beyond the control of the affected facility, 
its contractors, or any entity controlled by the affected facility that 
prevents you from complying with the requirement to submit a report 
electronically within the time period prescribed. Examples of such 
events are acts of nature (e.g., hurricanes, earthquakes, or floods), 
acts of war or terrorism, or equipment failure or safety hazard beyond 
the control of the affected facility (e.g., large scale power outage).
    (2) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (3) You must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.


Sec.  60.488b  Reconstruction.

    For the purposes of this subpart:
    (a) The cost of the following frequently replaced components of the 
facility shall not be considered in calculating either the ``fixed 
capital cost of the new components'' or the ``fixed capital costs that 
would be required to construct a comparable new facility'' under Sec.  
60.15: Pump seals, nuts and bolts, rupture disks, and packings.
    (b) Under Sec.  60.15, the ``fixed capital cost of new components'' 
includes the fixed capital cost of all depreciable components (except 
components specified in Sec.  60.488b(a)) which are or will be replaced 
pursuant to all continuous programs of component replacement which are 
commenced within any 2-year period following the applicability date for 
the appropriate subpart. (See the ``Applicability and designation of 
affected facility'' section of the appropriate subpart.) For purposes 
of this paragraph, ``commenced'' means that an owner or operator has 
undertaken a continuous program of component replacement or that an 
owner or operator has entered into a contractual obligation to 
undertake and complete, within a reasonable time, a continuous program 
of component replacement.


Sec.  60.489b  List of chemicals produced by affected facilities.

    Process units that produce, as intermediates or final products, 
chemicals listed in Sec.  60.489 are covered under this subpart. The 
applicability date for process units producing one or more of these 
chemicals is April 25, 2023.

0
18. Revise the heading of subpart III to read as follows:

Subpart III--Standards of Performance for Volatile Organic Compound 
(VOC) Emissions From the Synthetic Organic Chemical Manufacturing 
Industry (SOCMI) Air Oxidation Unit Processes After October 21, 
1983, and on or Before April 25, 2023

0
19. Amend Sec.  60.610 by revising paragraph (b) introductory text and 
adding paragraph (e) to read as follows:


Sec.  60.610  Applicability and designation of affected facility.

* * * * *
    (b) The affected facility is any of the following for which 
construction, modification, or reconstruction commenced after October 
21, 1983, and on or before April 25, 2023:
* * * * *
    (e) Owners and operators of flares that are subject to the flare 
related requirements of this subpart and flare related requirements of 
any other regulation in this part or 40 CFR part 61 or 63, may elect to 
comply with the requirements in Sec.  60.619a in lieu of all flare 
related requirements in any other regulation in this part or 40 CFR 
part 61 or 63.

0
20. Amend Sec.  60.611 by revising the definition of ``Flame zone'' to 
read as follows:


Sec.  60.611  Definitions.

* * * * *
    Flame zone means the portion of the combustion chamber in a boiler 
or process heater occupied by the flame envelope.
* * * * *

0
21. Amend Sec.  60.613 by revising paragraphs (e)(1)(i), (e)(2)(i), and 
(e)(3)(i) to read as follows:


Sec.  60.613  Monitoring of emissions and operations.

* * * * *
    (e) * * *
    (1) * * *
    (i) A scrubbing liquid temperature monitoring device having an 
accuracy of 1 percent of the temperature being monitored 
expressed in degrees Celsius or 0.5 [deg]C, whichever is greater, and a 
specific gravity monitoring device having an accuracy of 0.02 specific 
gravity units, each equipped with a continuous recorder; or
* * * * *
    (2) * * *
    (i) A condenser exit (product side) temperature monitoring device 
equipped with a continuous recorder and having an accuracy of 1 percent of the temperature being monitored expressed in degrees 
Celsius or 0.5 [deg]C, whichever is greater; or
* * * * *
    (3) * * *
    (i) An integrating steam flow monitoring device having an accuracy 
of 10 percent, and a carbon bed temperature monitoring device having an 
accuracy of 1 percent of the temperature being monitored 
expressed in degrees Celsius or 0.5 [deg]C, whichever is 
greater, both equipped with a continuous recorder; or
* * * * *

0
22. Amend Sec.  60.614 by revising paragraphs (b)(4) introductory text 
and (e) to read as follows:

[[Page 43087]]

Sec.  60.614  Test methods and procedures.

* * * * *
    (b) * * *
    (4) Method 18 of appendix A-6 to this part to determine 
concentration of TOC in the control device outlet and the concentration 
of TOC in the inlet when the reduction efficiency of the control device 
is to be determined. ASTM D6420-18 (incorporated by reference, see 
Sec.  [thinsp]60.17) may be used in lieu of Method 18, if the target 
compounds are all known and are all listed in Section 1.1 of ASTM 
D6420-18 as measurable; ASTM D6420-18 may not be used for methane and 
ethane; and ASTM D6420-18 may not be used as a total VOC method.
* * * * *
    (e) The following test methods, except as provided under Sec.  
60.8(b), shall be used for determining the net heating value of the gas 
combusted to determine compliance under Sec.  60.612(b) and for 
determining the process vent stream TRE index value to determine 
compliance under Sec.  60.612(c).
    (1)(i) Method 1 or 1A of appendix A-1 to this part, as appropriate, 
for selection of the sampling site. The sampling site for the vent 
stream flow rate and molar composition determination prescribed in 
Sec.  60.614(e)(2) and (3) shall be, except for the situations outlined 
in paragraph (e)(1)(ii) of this section, prior to the inlet of any 
control device, prior to any post-reactor dilution of the stream with 
air, and prior to any post-reactor introduction of halogenated 
compounds into the vent stream. No transverse site selection method is 
needed for vents smaller than 10 centimeters (4 inches) in diameter.
    (ii) If any gas stream other than the air oxidation vent stream 
from the affected facility is normally conducted through the final 
recovery device.
    (A) The sampling site for vent stream flow rate and molar 
composition shall be prior to the final recovery device and prior to 
the point at which the nonair oxidation stream is introduced.
    (B) The efficiency of the final recovery device is determined by 
measuring the TOC concentration using Method 18 of appendix A-6 to this 
part, or ASTM D6420-18 (incorporated by reference, see Sec.  
[thinsp]60.17) as specified in paragraph (b)(4) of this section, at the 
inlet to the final recovery device after the introduction of any nonair 
oxidation vent stream and at the outlet of the final recovery device.
    (C) This efficiency is applied to the TOC concentration measured 
prior to the final recovery device and prior to the introduction of the 
nonair oxidation stream to determine the concentration of TOC in the 
air oxidation stream from the final recovery device. This concentration 
of TOC is then used to perform the calculations outlined in Sec.  
60.614(e)(4) and (5).
    (2) The molar composition of the process vent stream shall be 
determined as follows:
    (i) Method 18 of appendix A-6 to this part, or ASTM D6420-18 
(incorporated by reference, see Sec.  [thinsp]60.17) as specified in 
paragraph (b)(4) of this section, to measure the concentration of TOC 
including those containing halogens.
    (ii) D1946-77 or 90 (Reapproved 1994) (incorporation by reference, 
see Sec.  60.17) to measure the concentration of carbon monoxide and 
hydrogen.
    (iii) Method 4 of appendix A to this part to measure the content of 
water vapor.
    (3) The volumetric flow rate shall be determined using Method 2, 
2A, 2C, or 2D of appendix A-1 to this part, as appropriate.
    (4) The net heating value of the vent stream shall be calculated 
using the following equation:
Equation 6 to Paragraph (e)(4)
[GRAPHIC] [TIFF OMITTED] TR16MY24.026

Where:

HT = Net heating value of the sample, MJ/scm (Btu/scf), 
where the net enthalpy per mole of vent stream is based on 
combustion at 25 [deg]C and 760 mm Hg (77 [deg]F and 30 in. Hg), but 
the standard temperature for determining the volume corresponding to 
one mole is 20 [deg]C (68 [deg]F).
K1 = 1.74 x 10-7 (1/ppm)(g-mole/scm)(MJ/kcal) 
(metric units), where standard temperature for (g-mole/scm) is 20 
[deg]C.
= 1.03 x 10-11 (1/ppm)(lb-mole/scf)(Btu/kcal) (English 
units) where standard temperature for (lb/mole/scf) is 68 [deg]F.
Cj = Concentration on a wet basis of compound j in ppm, 
as measured for organics by Method 18 of appendix A-6 to this part, 
or ASTM D6420-18 (incorporated by reference, see Sec.  
[thinsp]60.17) as specified in paragraph (b)(4) of this section, and 
measured for hydrogen and carbon monoxide by ASTM D1946-77, 90, or 
94 (incorporation by reference, see Sec.  60.17) as indicated in 
paragraph (e)(2) of this section.
Hj = Net heat of combustion of compound j, kcal/(g-mole) 
[kcal/(lb-mole)], based on combustion at 25 [deg]C and 760 mm Hg (77 
[deg]F and 30 in. Hg).

    (5) The emission rate of TOC in the process vent stream shall be 
calculated using the following equation:
Equation 7 to Paragraph (e)(5)
[GRAPHIC] [TIFF OMITTED] TR16MY24.027

Where:

ETOC = Measured emission rate of TOC, kg/hr (lb/hr).
K2 = 2.494 x 10-6 (1/ppm)(g-mole/scm)(kg/
g)(min/hr) (metric units), where standard temperature for (g-mole/
scm) is 20 [deg]C.
= 1.557 x 10-7 (1/ppm)(lb-mole/scf)(min/hr) (English 
units), where standard temperature for (lb-mole/scf) is 68 [deg]F.
Cj = Concentration on a wet basis of compound j in ppm, 
as measured by Method 18 of appendix A-6 to this part, or ASTM 
D6420-18 (incorporated by reference, see Sec.  [thinsp]60.17) as 
specified in paragraph (b)(4) of this section, as indicated in 
paragraph (e)(2) of this section.
Mj = Molecular weight of sample j, g/g-mole (lb/lb-mole).
Qs = Vent stream flow rate, scm/hr (scf/hr), at a 
temperature of 20 [deg]C (68 [deg]F).

    (6) The total process vent stream concentration (by volume) of 
compounds containing halogens (ppmv, by compound) shall be summed from 
the individual concentrations of compounds containing halogens which 
were measured by Method 18 of appendix A-6 to this part, or ASTM D6420-
18 (incorporated by reference,

[[Page 43088]]

see Sec.  60.17) as specified in paragraph (b)(4) of this section.
* * * * *

0
23. Amend Sec.  60.615 by revising paragraphs (b) introductory text, 
(j) introductory text, and (k) and adding paragraphs (m), (n), and (o) 
to read as follows:


Sec.  60.615  Reporting and recordkeeping requirements.

* * * * *
    (b) Each owner or operator subject to the provisions of this 
subpart shall keep up-to-date, readily accessible records of the 
following data measured during each performance test, and also include 
the following data in the report of the initial performance test 
required under Sec.  60.8. Where a boiler or process heater with a 
design heat input capacity of 44 MW (150 million Btu/hour) or greater 
is used to comply with Sec.  60.612(a), a report containing performance 
test data need not be submitted, but a report containing the 
information of Sec.  60.615(b)(2)(i) is required. The same data 
specified in this section shall be submitted in the reports of all 
subsequently required performance tests where either the emission 
control efficiency of a control device, outlet concentration of TOC, or 
the TRE index value of a vent stream from a recovery system is 
determined. Beginning on July 15, 2024, owners and operators must 
submit the performance test report following the procedures specified 
in paragraph (m) of this section. Data collected using test methods 
that are supported by the EPA's Electronic Reporting Tool (ERT) as 
listed on the EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of 
the test must be submitted in a file format generated using the EPA's 
ERT. Alternatively, the owner or operator may submit an electronic file 
consistent with the extensible markup language (XML) schema listed on 
the EPA's ERT website. Data collected using test methods that are not 
supported by the EPA's ERT as listed on the EPA's ERT website at the 
time of the test must be included as an attachment in the ERT or an 
alternate electronic file.
* * * * *
    (j) Each owner or operator that seeks to comply with the 
requirements of this subpart by complying with the requirements of 
Sec.  60.612 shall submit to the Administrator semiannual reports of 
the following information. The initial report shall be submitted within 
6 months after the initial start-up-date. On and after July 15, 2025 or 
once the report template for this subpart has been available on the 
Compliance and Emissions Data Reporting Interface (CEDRI) website 
(https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 
year, whichever date is later, owners and operators must submit all 
subsequent reports using the appropriate electronic report template on 
the CEDRI website for this subpart and following the procedure 
specified in paragraph (m) of this section. The date report templates 
become available will be listed on the CEDRI website. Unless the 
Administrator or delegated state agency or other authority has approved 
a different schedule for submission of reports, the report must be 
submitted by the deadline specified in this subpart, regardless of the 
method in which the report is submitted.
* * * * *
    (k) The requirements of Sec.  60.615(j) remain in force until and 
unless EPA, in delegating enforcement authority to a State under 
section 111(c) of the Act, approves reporting requirements or an 
alternative means of compliance surveillance adopted by such State. In 
that event, affected sources within the State will be relieved of the 
obligation to comply with Sec.  60.615(j), provided that they comply 
with the requirements established by the State. The EPA will not 
approve a waiver of electronic reporting to the EPA in delegating 
enforcement authority. Thus, electronic reporting to the EPA cannot be 
waived, and as such, the provisions of this paragraph cannot be used to 
relieve owners or operators of affected facilities of the requirement 
to submit the electronic reports required in this section to the EPA.
* * * * *
    (m) If an owner or operator is required to submit notifications or 
reports following the procedure specified in this paragraph (m), the 
owner or operator must submit notifications or reports to the EPA via 
CEDRI, which can be accessed through the EPA's Central Data Exchange 
(CDX) (https://cdx.epa.gov/). The EPA will make all the information 
submitted through CEDRI available to the public without further notice 
to the owner or operator. Do not use CEDRI to submit information the 
owner or operator claims as CBI. Although the EPA does not expect 
persons to assert a claim of CBI, if an owner or operator wishes to 
assert a CBI claim for some of the information in the report or 
notification, the owner or operator must submit a complete file in the 
format specified in this subpart, including information claimed to be 
CBI, to the EPA following the procedures in paragraphs (m)(1) and (2) 
of this section. Clearly mark the part or all of the information 
claimed to be CBI. Information not marked as CBI may be authorized for 
public release without prior notice. Information marked as CBI will not 
be disclosed except in accordance with procedures set forth in 40 CFR 
part 2. All CBI claims must be asserted at the time of submission. 
Anything submitted using CEDRI cannot later be claimed CBI. 
Furthermore, under CAA section 114(c), emissions data is not entitled 
to confidential treatment, and the EPA is required to make emissions 
data available to the public. Thus, emissions data will not be 
protected as CBI and will be made publicly available. The owner or 
operator must submit the same file submitted to the CBI office with the 
CBI omitted to the EPA via the EPA's CDX as described earlier in this 
paragraph (m).
    (1) The preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
[email protected], and as described above, should include clear CBI 
markings. ERT files should be flagged to the attention of the Group 
Leader, Measurement Policy Group; all other files should be flagged to 
the attention of the SOCMI NSPS Sector Lead. Owners and operators who 
do not have their own file sharing service and who require assistance 
with submitting large electronic files that exceed the file size limit 
for email attachments should email [email protected] to request a file 
transfer link.
    (2) If an owner or operator cannot transmit the file 
electronically, the owner or operator may send CBI information through 
the postal service to the following address: OAQPS Document Control 
Officer (C404-02), OAQPS, U.S. Environmental Protection Agency, 109 
T.W. Alexander Drive, P.O. Box 12055, Research Triangle Park, North 
Carolina 27711. ERT files should be sent to the attention of the Group 
Leader, Measurement Policy Group, and all other files should be sent to 
the attention of the SOCMI NSPS Sector Lead. The mailed CBI material 
should be double wrapped and clearly marked. Any CBI markings should 
not show through the outer envelope.
    (n) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX may assert a 
claim of EPA system outage for failure to timely comply with the 
electronic submittal requirement. To assert a claim of EPA system 
outage,

[[Page 43089]]

owners and operators must meet the requirements outlined in paragraphs 
(n)(1) through (7) of this section.
    (1) The owner or operator must have been or will be precluded from 
accessing CEDRI and submitting a required report within the time 
prescribed due to an outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (5) The owner or operator must provide to the Administrator a 
written description identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which the owner or operator proposes to report, or 
if the owner or operator has already met the reporting requirement at 
the time of the notification, the date the report was submitted.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (o) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX, owners and 
operators may assert a claim of force majeure for failure to timely 
comply with the electronic submittal requirement. To assert a claim of 
force majeure, you must meet the requirements outlined in paragraphs 
(o)(1) through (5) of this section.
    (1) An owner or operator may submit a claim if a force majeure 
event is about to occur, occurs, or has occurred or there are lingering 
effects from such an event within the period of time beginning five 
business days prior to the date the submission is due. For the purposes 
of this section, a force majeure event is defined as an event that will 
be or has been caused by circumstances beyond the control of the 
affected facility, its contractors, or any entity controlled by the 
affected facility that prevents the owner or operator from complying 
with the requirement to submit a report electronically within the time 
period prescribed. Examples of such events are acts of nature (e.g., 
hurricanes, earthquakes, or floods), acts of war or terrorism, or 
equipment failure or safety hazard beyond the control of the affected 
facility (e.g., large scale power outage).
    (2) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (3) The owner or operator must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which the owner or operator proposes to report, or 
if the owner or operator has already met the reporting requirement at 
the time of the notification, the date the report was submitted.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.

0
24. Amend Sec.  60.618 by revising paragraph (b) to read as follows:


Sec.  60.618  Delegation of authority.

* * * * *
    (b) Authorities which will not be delegated to States: Sec.  
60.613(e) and approval of an alternative to any electronic reporting to 
the EPA required by this subpart.

0
25. Add subpart IIIa to read as follows:
Subpart IIIa--Standards of Performance for Volatile Organic Compound 
(VOC) Emissions From the Synthetic Organic Chemical Manufacturing 
Industry (SOCMI) Air Oxidation Unit Processes for Which Construction, 
Reconstruction, or Modification Commenced After April 25, 2023
Sec.
60.610a Am I subject to this subpart?
60.611a What definitions must I know?
60.612a What standards and associated requirements must I meet?
60.613a What are my monitoring, installation, operation, and 
maintenance requirements?
60.614a What test methods and procedures must I use to determine 
compliance with the standards?
60.615a What records must I keep and what reports must I submit?
60.616a What do the terms associated with reconstruction mean for 
this subpart?
60.617a What are the chemicals that I must produce to be affected by 
subpart IIIa?
60.618a [Reserved]
60.619a What are my requirements if I use a flare to comply with 
this subpart?
60.620a What are my requirements for closed vent systems?
Table 1 to Subpart IIIa of Part 60--Emission Limits and Standards 
for Vent Streams
Table 2 to Subpart IIIa of Part 60--Monitoring Requirements for 
Complying With 98 Weight-Percent Reduction of Total Organic 
Compounds Emissions or a Limit of 20 Parts Per Million by Volume
Table 3 to Subpart IIIa of Part 60--Operating Parameters, Operating 
Parameter Limits and Data Monitoring, Recordkeeping and Compliance 
Frequencies
Table 4 to Subpart IIIa of Part 60--Calibration and Quality Control 
Requirements for Continuous Parameter Monitoring System (CPMS)

Subpart IIIa--Standards of Performance for Volatile Organic 
Compound (VOC) Emissions From the Synthetic Organic Chemical 
Manufacturing Industry (SOCMI) Air Oxidation Unit Processes for 
Which Construction, Reconstruction, or Modification Commenced After 
April 25, 2023


Sec.  60.610a  Am I subject to this subpart?

    (a) You are subject to this subpart if you operate an affected 
facility designated in paragraph (b) of this section that produces any 
of the chemicals listed in Sec.  60.617a as a product, co-product, by-
product, or intermediate, except as provided in paragraph (c) of this 
section.
    (b) The affected facility is any of the following for which 
construction, modification, or reconstruction commenced after April 25, 
2023:
    (1) Each air oxidation reactor not discharging its vent stream into 
a recovery system.
    (2) Each combination of an air oxidation reactor and the recovery 
system into which its vent stream is discharged.
    (3) Each combination of two or more air oxidation reactors and the 
common recovery system into which their vent streams are discharged.
    (c) Exemptions from the provisions of paragraph (a) of this section 
are as follows:
    (1) Each affected facility operated with a vent stream flow rate 
less than

[[Page 43090]]

0.001 pound per hour (lb/hr) of TOC is exempt from all provisions of 
this subpart except for the test method and procedure and the 
recordkeeping and reporting requirements in Sec.  60.614a(e) and Sec.  
60.615a(h), (i)(8), and (n).
    (2) A vent stream going to a fuel gas system as defined in Sec.  
63.611a.


Sec.  60.611a  What definitions must I know?

    As used in this subpart, all terms not defined herein have the 
meaning given them in the Clean Air Act and subpart A of this part.
    Air Oxidation Reactor means any device or process vessel in which 
one or more organic reactants are combined with air, or a combination 
of air and oxygen, to produce one or more organic compounds. 
Ammoxidation and oxychlorination reactions are included in this 
definition.
    Air Oxidation Reactor Recovery Train means an individual recovery 
system receiving the vent stream from at least one air oxidation 
reactor, along with all air oxidation reactors feeding vent streams 
into this system.
    Air Oxidation Unit Process means a unit process, including 
ammoxidation and oxychlorination unit process, that uses air, or a 
combination of air and oxygen, as an oxygen source in combination with 
one or more organic reactants to produce one or more organic compounds.
    Boilers means any enclosed combustion device that extracts useful 
energy in the form of steam.
    Breakthrough means the time when the level of TOC, measured at the 
outlet of the first bed, has been detected is at the highest 
concentration allowed to be discharged from the adsorber system and 
indicates that the adsorber bed should be replaced.
    By Compound means by individual stream components, not carbon 
equivalents.
    Closed vent system means a system that is not open to the 
atmosphere and is composed of piping, ductwork, connections, and, if 
necessary, flow inducing devices that transport gas or vapor from an 
emission point to a control device.
    Continuous recorder means a data recording device recording an 
instantaneous data value at least once every 15 minutes.
    Flame zone means the portion of the combustion chamber in a boiler 
or process heater occupied by the flame envelope.
    Flow indicator means a device which indicates whether gas flow is 
present in a vent stream.
    Fuel gas means gases that are combusted to derive useful work or 
heat.
    Fuel gas system means the offsite and onsite piping and flow and 
pressure control system that gathers gaseous stream(s) generated by 
onsite operations, may blend them with other sources of gas, and 
transports the gaseous stream for use as fuel gas in combustion devices 
or in in-process combustion equipment such as furnaces and gas turbines 
either singly or in combination.
    Halogenated vent stream means any vent stream determined to have a 
total concentration (by volume) of compounds containing halogens of 20 
ppmv (by compound) or greater.
    Incinerator means any enclosed combustion device that is used for 
destroying organic compounds and does not extract energy in the form of 
steam or process heat.
    Pressure-assisted multi-point flare means a flare system consisting 
of multiple flare burners in staged arrays whereby the vent stream 
pressure is used to promote mixing and smokeless operation at the flare 
burner tips. Pressure-assisted multi-point flares are designed for 
smokeless operation at velocities up to Mach = 1 conditions (i.e., 
sonic conditions), can be elevated or at ground level, and typically 
use cross-lighting for flame propagation to combust any flare vent 
gases sent to a particular stage of flare burners.
    Primary fuel means the fuel fired through a burner or a number of 
similar burners. The primary fuel provides the principal heat input to 
the device, and the amount of fuel is sufficient to sustain operation 
without the addition of other fuels.
    Process heater means a device that transfers heat liberated by 
burning fuel to fluids contained in tubes, including all fluids except 
water that is heated to produce steam.
    Process unit means equipment assembled and connected by pipes or 
ducts to produce, as intermediates or final products, one or more of 
the chemicals in Sec.  60.617a. A process unit can operate 
independently if supplied with sufficient fuel or raw materials and 
sufficient product storage facilities.
    Product means any compound or chemical listed in Sec.  60.617a that 
is produced for sale as a final product as that chemical or is produced 
for use in a process that needs that chemical for the production of 
other chemicals in another facility. By-products, co-products, and 
intermediates are considered to be products.
    Recovery device means an individual unit of equipment, such as an 
absorber, condenser, and carbon adsorber, capable of and used to 
recover chemicals for use, reuse, or sale.
    Recovery system means an individual recovery device or series of 
such devices applied to the same process stream.
    Relief valve means a valve used only to release an unplanned, 
nonroutine discharge. A relief valve discharge results from an operator 
error, a malfunction such as a power failure or equipment failure, or 
other unexpected cause that requires immediate venting of gas from 
process equipment in order to avoid safety hazards or equipment damage.
    Total organic compounds (TOC) means those compounds measured 
according to the procedures of Method 18 of appendix A-6 to this part 
or ASTM D6420-18 (incorporated by reference, see Sec. [thinsp]60.17) as 
specified in Sec.  60.614a(b)(4) or the concentration of organic 
compounds measured according to the procedures in Method 21 or Method 
25A of appendix A-7 to this part.
    Vent stream means any gas stream, containing nitrogen which was 
introduced as air to the air oxidation reactor, released to the 
atmosphere directly from any air oxidation reactor recovery train or 
indirectly, after diversion through other process equipment. The vent 
stream excludes equipment leaks including, but not limited to, pumps, 
compressors, and valves.


Sec.  60.612a  What standards and associated requirements must I meet?

    (a) You must comply with the emission limits and standards 
specified in Table 1 to this subpart and the requirements specified 
paragraphs (b) and (c) of this section for each vent stream on and 
after the date on which the initial performance test required by 
Sec. Sec.  60.8 and 60.614a is completed, but not later than 60 days 
after achieving the maximum production rate at which the affected 
facility will be operated, or 180 days after the initial start-up, 
whichever date comes first. The standards in this section apply at all 
times, including periods of startup, shutdown and malfunction. As 
provided in Sec.  60.11(f), this provision supersedes the exemptions 
for periods of startup, shutdown and malfunction in the general 
provisions in subpart A of this part.
    (b) The following release events from an affected facility are a 
violation of the emission limits and standards specified in table 1 to 
this subpart.
    (1) Any relief valve discharge to the atmosphere of a vent stream.
    (2) The use of a bypass line at any time on a closed vent system to 
divert emissions to the atmosphere, or to a control device or recovery 
device not

[[Page 43091]]

meeting the requirements specified in Sec.  60.613a.
    (c) You may designate a vent stream as a maintenance vent if the 
vent is only used as a result of startup, shutdown, maintenance, or 
inspection of equipment where equipment is emptied, depressurized, 
degassed, or placed into service. You must comply with the applicable 
requirements in paragraphs (c)(1) through (3) of this section for each 
maintenance vent. Any vent stream designated as a maintenance vent is 
only subject to the maintenance vent provisions in this paragraph (c) 
and the associated recordkeeping and reporting requirements in Sec.  
60.615a(g), respectively.
    (1) Prior to venting to the atmosphere, remove process liquids from 
the equipment as much as practical and depressurize the equipment to 
either: A flare meeting the requirements of Sec.  60.619a, as 
applicable, or using any combination of a non-flare control device or 
recovery device meeting the requirements in Table 1 to this subpart 
until one of the following conditions, as applicable, is met.
    (i) The vapor in the equipment served by the maintenance vent has a 
lower explosive limit (LEL) of less than 10 percent.
    (ii) If there is no ability to measure the LEL of the vapor in the 
equipment based on the design of the equipment, the pressure in the 
equipment served by the maintenance vent is reduced to 5 pounds per 
square inch gauge (psig) or less. Upon opening the maintenance vent, 
active purging of the equipment cannot be used until the LEL of the 
vapors in the maintenance vent (or inside the equipment if the 
maintenance is a hatch or similar type of opening) is less than 10 
percent.
    (iii) The equipment served by the maintenance vent contains less 
than 50 pounds of total VOC.
    (iv) If, after applying best practices to isolate and purge 
equipment served by a maintenance vent, none of the applicable 
criterion in paragraphs (c)(1)(i) through (iii) of this section can be 
met prior to installing or removing a blind flange or similar equipment 
blind, then the pressure in the equipment served by the maintenance 
vent must be reduced to 2 psig or less before installing or removing 
the equipment blind. During installation or removal of the equipment 
blind, active purging of the equipment may be used provided the 
equipment pressure at the location where purge gas is introduced 
remains at 2 psig or less.
    (2) Except for maintenance vents complying with the alternative in 
paragraph (c)(1)(iii) of this section, you must determine the LEL or, 
if applicable, equipment pressure using process instrumentation or 
portable measurement devices and follow procedures for calibration and 
maintenance according to manufacturer's specifications.
    (3) For maintenance vents complying with the alternative in 
paragraph (c)(1)(iii) of this section, you must determine mass of VOC 
in the equipment served by the maintenance vent based on the equipment 
size and contents after considering any contents drained or purged from 
the equipment. Equipment size may be determined from equipment design 
specifications. Equipment contents may be determined using process 
knowledge.


Sec.  60.613a  What are my monitoring, installation, operation, and 
maintenance requirements?

    (a) Except as specified in paragraphs (a)(5) through (7) of this 
section, if you use a non-flare control device or recovery system to 
comply with the TOC emission limit specified in Table 1 to this 
subpart, then you must comply with paragraphs (a)(1) through (4), (b), 
and (c) of this section.
    (1) Install a continuous parameter monitoring system(s) (CPMS) and 
monitor the operating parameter(s) applicable to the control device or 
recovery system as specified in Table 2 to this subpart or established 
according to paragraph (c) of this section.
    (2) Establish the applicable minimum, maximum, or range for the 
operating parameter limit as specified in Table 3 to this subpart or 
established according to paragraph (c) of this section by calculating 
the value(s) as the arithmetic average of operating parameter 
measurements recorded during the three test runs conducted for the most 
recent performance test. You may operate outside of the established 
operating parameter limit(s) during subsequent performance tests in 
order to establish new operating limits. You must include the updated 
operating limits with the performance test results submitted to the 
Administrator pursuant to Sec.  60.615a(b). Upon establishment of a new 
operating limit, you must thereafter operate under the new operating 
limit. If the Administrator determines that you did not conduct the 
performance test in accordance with the applicable requirements or that 
the operating limit established during the performance test does not 
correspond to the conditions specified in Sec.  60.614a(a), then you 
must conduct a new performance test and establish a new operating 
limit.
    (3) Monitor, record, and demonstrate continuous compliance using 
the minimum frequencies specified in Table 3 to this subpart or 
established according to paragraph (c) of this section.
    (4) Comply with the calibration and quality control requirements as 
specified in Table 4 to this subpart or established according to 
paragraph (c) of this section that are applicable to the CPMS used.
    (5) Any vent stream introduced with primary fuel into a boiler or 
process heater is exempt from the requirements specified in paragraphs 
(a)(1) through (4) of this section.
    (6) If you vent emissions through a closed vent system to an 
adsorber(s) that cannot be regenerated or a regenerative adsorber(s) 
that is regenerated offsite, then you must install a system of two or 
more adsorber units in series and comply with the requirements 
specified in paragraphs (a)(6)(i) through (iii) of this section in 
addition to the requirements specified in paragraphs (a)(1) through (4) 
of this section.
    (i) Conduct an initial performance test or design evaluation of the 
adsorber and establish the breakthrough limit and adsorber bed life.
    (ii) Monitor the TOC concentration through a sample port at the 
outlet of the first adsorber bed in series according to the schedule in 
paragraph (a)(6)(iii)(B) of this section. You must measure the 
concentration of TOC using either a portable analyzer, in accordance 
with Method 21 of appendix A-7 of this part using methane, propane, or 
isobutylene as the calibration gas or Method 25A of appendix A-7 of 
this part using methane or propane as the calibration gas.
    (iii) Comply with paragraph (a)(6)(iii)(A) of this section, and 
comply with the monitoring frequency according to paragraph 
(a)(6)(iii)(B) of this section.
    (A) The first adsorber in series must be replaced immediately when 
breakthrough, as defined in Sec.  60.611a, is detected between the 
first and second adsorber. The original second adsorber (or a fresh 
canister) will become the new first adsorber and a fresh adsorber will 
become the second adsorber. For purposes of this paragraph 
(a)(6)(iii)(A), ``immediately'' means within 8 hours of the detection 
of a breakthrough for adsorbers of 55 gallons or less, and within 24 
hours of the detection of a breakthrough for adsorbers greater than 55 
gallons. You must monitor at the outlet of the first adsorber within 3 
days of replacement to confirm it is performing properly.
    (B) Based on the adsorber bed life established according to 
paragraph (a)(6)(i) of this section and the date the

[[Page 43092]]

adsorbent was last replaced, conduct monitoring to detect breakthrough 
at least monthly if the adsorbent has more than 2 months of life 
remaining, at least weekly if the adsorbent has between 2 months and 2 
weeks of life remaining, and at least daily if the adsorbent has 2 
weeks or less of life remaining.
    (7) If you install a continuous emissions monitoring system (CEMS) 
to demonstrate compliance with the TOC standard in Table 1 of this 
subpart, you must comply with the requirements specified in Sec.  
60.614a(f) in lieu of the requirements specified in paragraphs (a)(1) 
through (4) and (c) of this section.
    (b) If you vent emissions through a closed vent system to a boiler 
or process heater, then the vent stream must be introduced into the 
flame zone of the boiler or process heater.
    (c) If you seek to demonstrate compliance with the standards 
specified under Sec.  60.612a with control devices other than an 
incinerator, boiler, process heater, or flare; or recovery devices 
other than an absorber, condenser, or carbon adsorber, you shall 
provide to the Administrator prior to conducting the initial 
performance test information describing the operation of the control 
device or recovery device and the parameter(s) which would indicate 
proper operation and maintenance of the device and how the parameter(s) 
are indicative of control of TOC emissions. The Administrator may 
request further information and will specify appropriate monitoring 
procedures or requirements, including operating parameters to be 
monitored, averaging times for determining compliance with the 
operating parameter limits, and ongoing calibration and quality control 
requirements.


Sec.  60.614a  What test methods and procedures must I use to determine 
compliance with the standards?

    (a) For the purpose of demonstrating compliance with the emission 
limits and standards specified in table 1 to this subpart, all affected 
facilities must be run at full operating conditions and flow rates 
during any performance test. Performance tests are not required if you 
determine compliance using a CEMS that meets the requirements outlined 
in paragraph (f) of this section.
    (1) Conduct initial performance tests no later than the date 
required by Sec.  60.8(a).
    (2) Conduct subsequent performance tests no later than 60 calendar 
months after the previous performance test.
    (b) The following methods, except as provided in Sec.  60.8(b) must 
be used as reference methods to determine compliance with the emission 
limit or percent reduction efficiency specified in table 1 to this 
subpart for non-flare control devices and/or recovery systems.
    (1) Method 1 or 1A of appendix A-1 to this part, as appropriate, 
for selection of the sampling sites. The inlet sampling site for 
determination of vent stream molar composition or TOC (less methane and 
ethane) reduction efficiency shall be prior to the inlet of the control 
device or, if equipped with a recovery system, then prior to the inlet 
of the first recovery device in the recovery system.
    (2) Method 2, 2A, 2C, or 2D of appendix A-1 to this part, as 
appropriate, for determination of the volumetric flow rates.
    (3) Method 3A of appendix A-2 to this part or the manual method in 
ANSI/ASME PTC 19.10-1981 (incorporated by reference, see Sec.  
[thinsp]60.17) must be used to determine the oxygen concentration 
(%O2d) for the purposes of determining compliance with the 20 ppmv 
limit. The sampling site must be the same as that of the TOC samples 
and the samples must be taken during the same time that the TOC samples 
are taken. The TOC concentration corrected to 3 percent O2 
(Cc) must be computed using the following equation:
Equation 1 to Paragraph (b)(3)
[GRAPHIC] [TIFF OMITTED] TR16MY24.028

Where:

Cc = Concentration of TOC corrected to 3 percent 
O2, dry basis, ppm by volume.
CTOC = Concentration of TOC (minus methane and ethane), 
dry basis, ppm by volume.
%O2d = Concentration of O2, dry basis, percent 
by volume.

    (4) Method 18 of appendix A-6 to this part to determine 
concentration of TOC in the control device outlet or in the outlet of 
the final recovery device in a recovery system, and to determine the 
concentration of TOC in the inlet when the reduction efficiency of the 
control device or recovery system is to be determined. ASTM D6420-18 
(incorporated by reference, see Sec.  60.17) may be used in lieu of 
Method 18, if the target compounds are all known and are all listed in 
Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 must not be 
used for methane and ethane; and ASTM D6420-18 may not be used as a 
total VOC method.
    (i) The sampling time for each run must be 1 hour in which either 
an integrated sample or at least four grab samples must be taken. If 
grab sampling is used then the samples must be taken at 15-minute 
intervals.
    (ii) The emission reduction (R) of TOC (minus methane and ethane) 
must be determined using the following equation:
Equation 2 to Paragraph (b)(4)(ii)
[GRAPHIC] [TIFF OMITTED] TR16MY24.029

Where:

R = Emission reduction, percent by weight.
Ei = Mass rate of TOC entering the control device or 
recovery system, kg/hr (lb/hr).
Eo = Mass rate of TOC discharged to the atmosphere, kg/hr 
(lb/hr).

    (iii) The mass rates of TOC (Ei, Eo) must be 
computed using the following equations:
Equations 3 and 4 to Paragraph (b)(4)(iii)

[[Page 43093]]

[GRAPHIC] [TIFF OMITTED] TR16MY24.030

Where:

Cij, Coj = Concentration of sample component 
``j'' of the gas stream at the inlet and outlet of the control 
device or recovery system, respectively, dry basis ppm by volume.
Mij, Moj = Molecular weight of sample 
component ``j'' of the gas stream at the inlet and outlet of the 
control device or recovery system, respectively, g/g-mole (lb/lb-
mole).
Qi, Qo = Flow rate of gas stream at the inlet 
and outlet of the control device or recovery system, respectively, 
dscm/min (dscf/min).
K2 = 2.494 x 10-6 (1/ppm)(g-mole/scm)(kg/
g)(min/hr) (metric units), where standard temperature for (g-mole/
scm) is 20 [deg]C.
= 1.557 x 10-7 (1/ppm)(lb-mole/scf)(min/hr) (English 
units), where standard temperature for (lb-mole/scf) is 68 [deg]F.

    (iv) The TOC concentration (CTOC) is the sum of the 
individual components and must be computed for each run using the 
following equation:
Equation 5 to Paragraph (b)(4)(iv)
[GRAPHIC] [TIFF OMITTED] TR16MY24.031

Where:

CTOC = Concentration of TOC (minus methane and ethane), 
dry basis, ppm by volume.
Cj = Concentration of sample components in the sample.
n = Number of components in the sample.

    (c) The requirement for initial and subsequent performance tests 
are waived, in accordance with Sec.  60.8(b), for the following:
    (1) When a boiler or process heater with a design heat input 
capacity of 44 MW (150 million Btu/hour) or greater is used to seek 
compliance with the emission limit or percent reduction efficiency 
specified in table 1 to this subpart.
    (2) When a vent stream is introduced into a boiler or process 
heater with the primary fuel.
    (3) When a boiler or process heater burning hazardous waste is used 
for which the owner or operator:
    (i) Has been issued a final permit under 40 CFR part 270 and 
complies with the requirements of 40 CFR part 266, subpart H;
    (ii) Has certified compliance with the interim status requirements 
of 40 CFR part 266, subpart H;
    (iii) Has submitted a Notification of Compliance under 40 CFR 
63.1207(j) and complies with the requirements of 40 CFR part 63, 
subpart EEE; or
    (iv) Complies with 40 CFR part 63, subpart EEE and will submit a 
Notification of Compliance under 40 CFR 63.1207(j) by the date the 
owner or operator would have been required to submit the initial 
performance test report for this subpart.
    (4) The Administrator reserves the option to require testing at 
such other times as may be required, as provided for in section 114 of 
the Act.
    (d) For purposes of complying with the 98 weight-percent reduction 
in Sec.  60.612a(a), if the vent stream entering a boiler or process 
heater with a design capacity less than 44 MW (150 million Btu/hour) is 
introduced with the combustion air or as secondary fuel, the weight-
percent reduction of TOC (minus methane and ethane) across the 
combustion device shall be determined by comparing the TOC (minus 
methane and ethane) in all combusted vent streams, primary fuels, and 
secondary fuels with the TOC (minus methane and ethane) exiting the 
combustion device.
    (e) Any owner or operator subject to the provisions of this subpart 
seeking to demonstrate compliance with Sec.  60.610a(c)(1) must use the 
following methods:
    (1) Method 1 or 1A of appendix A-1 to this part, as appropriate.
    (2) Method 2, 2A, 2C, or 2D of appendix A-1 to this part, as 
appropriate, for determination of the gas volumetric flow rates.
    (3) Method 18 of appendix A-6 to this part to determine the 
concentration of TOC. ASTM D6420-18 (incorporated by reference, see 
Sec.  60.17) may be used in lieu of Method 18, if the target compounds 
are all known and are all listed in Section 1.1 of ASTM D6420-18 as 
measurable; ASTM D6420-18 may not be used for methane and ethane; and 
ASTM D6420-18 must not be used as a total VOC method.
    (i) The sampling site must be at a location that provides a 
representative sample of the vent stream.
    (ii) Perform three test runs. The sampling time for each run must 
be 1 hour in which either an integrated sample or at least four grab 
samples must be taken. If grab sampling is used then the samples must 
be taken at 15-minute intervals.
    (iii) The mass rate of TOC (E) must be computed using the following 
equation:
Equation 6 to Paragraph (e)(3)(ii)
[GRAPHIC] [TIFF OMITTED] TR16MY24.032

Where:

Cj = Concentration of sample component ``j'' of the gas 
stream at the representative sampling location, dry basis, ppm by 
volume.
Mj = Molecular weight of sample component ``j'' of the 
gas stream at the representative sampling location, g/g-mole (lb/lb-
mole).

[[Page 43094]]

Q = Flow rate of gas stream at the representative sampling location, 
dscm/min (dscf/min).
K = 2.494 x 10-6 (1/ppm)(g-mole/scm) (kg/g) (min/hr) 
(metric units), where standard temperature for (g-mole/scm) is 20 
[deg]C.
= 1.557 x 10-7 (1/ppm) (lb-mole/scf) (min/hr) (English 
units), where standard temperature for (lb-mole/scf) is 68 [deg]F.

    (f) If you use a CEMS to demonstrate initial and continuous 
compliance with the TOC standard in table 1 of this subpart, each CEMS 
must be installed, operated and maintained according to the 
requirements in Sec.  60.13 and paragraphs (f)(1) through (5) of this 
section.
    (1) You must use a CEMS that is capable of measuring the target 
analyte(s) as demonstrated using either process knowledge of the 
control device inlet stream or the screening procedures of Method 18 of 
appendix A-6 to this part on the control device inlet stream. If your 
CEMS is located after a combustion device and inlet stream to that 
device includes methanol or formaldehyde, you must use a CEMS which 
meets the requirements in Performance Specification 9 or 15 of appendix 
B to this part.
    (2) Each CEMS must be installed, operated, and maintained according 
to the applicable performance specification of appendix B to this part 
and the applicable quality assurance procedures of appendix F to this 
part. Locate the sampling probe or other interface at a measurement 
location such that you obtain representative measurements of emissions 
from the affected facility.
    (3) Conduct a performance evaluation of each CEMS within 180 days 
of installation of the monitoring system. Conduct subsequent 
performance evaluations of the CEMS no later than 12 calendar months 
after the previous performance evaluation. The results each performance 
evaluation must be submitted in accordance with Sec.  60.615a(b)(1).
    (4) You must determine TOC concentration according to one of the 
following options. The span value of the TOC CEMS must be approximately 
2 times the emission standard specified in table 1 of this subpart.
    (i) For CEMS meeting the requirements of Performance Specification 
15 of appendix B to this part, determine the target analyte(s) for 
calibration using either process knowledge of the control device inlet 
stream or the screening procedures of Method 18 of appendix A-6 to this 
part on the control device inlet stream. The individual analytes used 
to quantify TOC must represent 98 percent of the expected mass of TOC 
present in the stream. Report the results of TOC as equivalent to 
carbon (C1).
    (ii) For CEMS meeting the requirements of Performance Specification 
9 of appendix B to this part, determine the target analyte(s) for 
calibration using either process knowledge of the control device inlet 
stream or the screening procedures of Method 18 of appendix A-6 to this 
part on the control device inlet stream. The individual analytes used 
to quantify TOC must represent 98 percent of the expected mass of TOC 
present in the stream. Report the results of TOC as equivalent to 
carbon (C1).
    (iii) For CEMS meeting the requirements of Performance 
Specification 8 of appendix B to this part used to monitor performance 
of a combustion device, calibrate the instrument on the predominant 
organic HAP and report the results as carbon (C1), and use Method 25A 
of appendix A-7 to this part as the reference method for the relative 
accuracy tests. You must also comply with procedure 1 of appendix F to 
this part.
    (iv) For CEMS meeting the requirements of Performance Specification 
8 of appendix B to this part used to monitor performance of a 
noncombustion device, determine the predominant organic compound using 
either process knowledge or the screening procedures of Method 18 of 
appendix A-6 to this part on the control device inlet stream. Calibrate 
the monitor on the predominant organic compound and report the results 
as C1. Use Method 25A of appendix A-7 to this part as the 
reference method for the relative accuracy tests. You must also comply 
with procedure 1 of appendix F to this part.
    (5) You must determine stack oxygen concentration at the same 
location where you monitor TOC concentration with a CEMS that meets the 
requirements of Performance Specification 3 of appendix B to this part. 
The span value of the oxygen CEMS must be approximately 25 percent 
oxygen. Use Method 3A of appendix A-2 to this part as the reference 
method for the relative accuracy tests.
    (6) You must maintain written procedures for your CEMS. At a 
minimum, the procedures must include the information in paragraphs 
(f)(6)(i) through (vi) of this section:
    (i) Description of CEMS installation location.
    (ii) Description of the monitoring equipment, including the 
manufacturer and model number for all monitoring equipment components 
and the span of the analyzer.
    (iii) Routine quality control and assurance procedures.
    (iv) Conditions that would trigger a CEMS performance evaluation, 
which must include, at a minimum, a newly installed CEMS; a process 
change that is expected to affect the performance of the CEMS; and the 
Administrator's request for a performance evaluation under section 114 
of the Clean Air Act.
    (v) Ongoing operation and maintenance procedures.
    (vi) Ongoing recordkeeping and reporting procedures.


Sec.  60.615a  What records must I keep and what reports must I submit?

    (a) You must notify the Administrator of the specific provisions of 
table 1 to this subpart or Sec.  60.612a(c) with which you have elected 
to comply. Notification must be submitted with the notification of 
initial start-up required by Sec.  60.7(a)(3). If you elect at a later 
date to use an alternative provision of table 1 to this subpart with 
which you will comply, then you must notify the Administrator 90 days 
before implementing a change and, upon implementing the change, you 
must conduct a performance test as specified by Sec.  60.614a within 
180 days.
    (b) If you use a non-flare control device or recovery system to 
comply with the TOC emission limit specified in table 1 to this 
subpart, then you must keep up-to-date, readily accessible records of 
the data measured during each performance test to show compliance with 
the TOC emission limit. You must also include all of the data you use 
to comply with Sec.  60.613a(a)(2). The same data specified in this 
paragraph must also be submitted in the initial performance test 
required in Sec.  60.8 and the reports of all subsequently required 
performance tests where either the emission reduction efficiency of a 
control device or recovery system or outlet concentration of TOC is 
determined. Alternatively, you must keep records of each CEMS 
performance evaluation.
    (1) Within 60 days after the date of completing each performance 
test or CEMS performance evaluation required by this subpart, you must 
submit the results of the performance test or performance evaluation 
following the procedures specified in paragraph (j) of this section. 
Data collected using test methods and performance evaluations of CEMS 
measuring relative accuracy test audit (RATA) pollutants supported by 
the EPA's Electronic Reporting Tool (ERT) as listed on the EPA's ERT 
website (https://www.epa.gov/

[[Page 43095]]

electronic-reporting-air-emissions/electronic-reporting-tool-ert) at 
the time of the test or performance evaluation must be submitted in a 
file format generated through the use of the EPA's ERT. Alternatively, 
owners and operators may submit an electronic file consistent with the 
extensible markup language (XML) schema listed on the EPA's ERT 
website. Data collected using test methods and performance evaluations 
of CEMS measuring RATA pollutants that are not supported by the EPA's 
ERT as listed on the EPA's ERT website at the time of the test must be 
included as an attachment in the ERT or alternate electronic file.
    (2) If you use a boiler or process heater with a design heat input 
capacity of 44 MW (150 million Btu/hour) or greater to comply with the 
TOC emission limit specified in Table 1 to this subpart, then you are 
not required to submit a report containing performance test data; 
however, you must submit a description of the location at which the 
vent stream is introduced into the boiler or process heater.
    (c) If you use a non-flare control device or recovery system to 
comply with the TOC emission limit specified in table 1 to this 
subpart, then you must keep up-to-date, readily accessible records of 
periods of operation during which the operating parameter limits 
established during the most recent performance test are exceeded or 
periods of operation where the TOC CEMS, averaged on a 3-hour block 
basis, indicate an exceedance of the emission standard in table 1 of 
this subpart. Additionally, you must record all periods when the TOC 
CEMS is inoperable. The Administrator may at any time require a report 
of these data. Periods of operation during which the operating 
parameter limits established during the most recent performance tests 
are exceeded are defined as follows:
    (1) For absorbers:
    (i) All 3-hour periods of operation during which the average 
absorbing liquid temperature was above the maximum absorbing liquid 
temperature established during the most recent performance test.
    (ii) All 3-hour periods of operation during which the average 
absorbing liquid specific gravity was outside the exit specific gravity 
range (i.e., more than 0.1 unit above, or more than 0.1 unit below, the 
average absorbing liquid specific gravity) established during the most 
recent performance test.
    (2) For boilers or process heaters:
    (i) Whenever there is a change in the location at which the vent 
stream is introduced into the flame zone as required under Sec.  
60.613a(b).
    (ii) If the boiler or process heater has a design heat input 
capacity of less than 44 MW (150 million Btu/hr), then all 3-hour 
periods of operation during which the average firebox temperature was 
below the minimum firebox temperature during the most recent 
performance test.
    (3) For catalytic incinerators:
    (i) All 3-hour periods of operation during which the average 
temperature of the vent stream immediately before the catalyst bed is 
below the minimum temperature of the vent stream established during the 
most recent performance test.
    (ii) All 3-hour periods of operation during which the average 
temperature difference across the catalyst bed is less than the average 
temperature difference of the device established during the most recent 
performance test.
    (4) For carbon adsorbers:
    (i) All carbon bed regeneration cycles during which the total mass 
stream flow or the total volumetric stream flow was below the minimum 
flow established during the most recent performance test.
    (ii) All carbon bed regeneration cycles during which the 
temperature of the carbon bed after regeneration (and after completion 
of any cooling cycle(s)) was greater than the maximum carbon bed 
temperature (in degrees Celsius) established during the most recent 
performance test.
    (5) For condensers, all 3-hour periods of operation during which 
the average exit (product side) condenser operating temperature was 
above the maximum exit (product side) operating temperature established 
during the most recent performance test.
    (6) For scrubbers used to control halogenated vent streams:
    (i) All 3-hour periods of operation during which the average pH of 
the scrubber effluent is below the minimum pH of the scrubber effluent 
established during the most recent performance test.
    (ii) All 3-hour periods of operation during which the average 
influent liquid flow to the scrubber is below the minimum influent 
liquid flow to the scrubber established during the most recent 
performance test.
    (iii) All 3-hour periods of operation during which the average 
liquid-to-gas ratio flow of the scrubber is below the minimum liquid-
to-gas ratio of the scrubber established during the most recent 
performance test.
    (7) For thermal incinerators, all 3-hour periods of operation 
during which the average firebox temperature was below the minimum 
firebox temperature established during the most recent performance 
test.
    (8) For all other control devices, all periods (for the averaging 
time specified by the Administrator) when the operating parameter(s) 
established under Sec.  60.613a(c) exceeded the operating limit 
established during the most recent performance test.
    (d) You must keep up-to-date, readily accessible continuous records 
of the flow indication specified in Table 2 to this subpart, as well as 
up-to-date, readily accessible records of all periods when the vent 
stream is diverted from the control device or recovery device or has no 
flow rate, including the records as specified in paragraphs (d)(1) and 
(2) of this section.
    (1) For each flow event from a relief valve discharge subject to 
the requirements in Sec.  60.612a(b)(1), you must include an estimate 
of the volume of gas, the concentration of TOC in the gas and the 
resulting emissions of TOC that released to the atmosphere using 
process knowledge and engineering estimates.
    (2) For each flow event from a bypass line subject to the 
requirements in Sec. Sec.  60.612a(b)(2) and 60.620a(e), you must 
maintain records sufficient to determine whether or not the detected 
flow included flow requiring control. For each flow event from a bypass 
line requiring control that is released either directly to the 
atmosphere or to a control device or recovery device not meeting the 
requirements in this subpart, you must include an estimate of the 
volume of gas, the concentration of TOC in the gas and the resulting 
emissions of TOC that bypassed the control device or recovery device 
using process knowledge and engineering estimates.
    (e) If you use a boiler or process heater with a design heat input 
capacity of 44 MW (150 million Btu/hour) or greater to comply with the 
TOC emission limit specified in Table 1 to this subpart, then you must 
keep an up-to-date, readily accessible record of all periods of 
operation of the boiler or process heater. (Examples of such records 
could include records of steam use, fuel use, or monitoring data 
collected pursuant to other State or Federal regulatory requirements).
    (f) If you use a flare to comply with the TOC emission standard 
specified in Table 1 to this subpart, then you must keep up-to-date, 
readily accessible records of all visible emission readings, heat 
content determinations, flow rate measurements, and exit velocity 
determinations made during the initial visible emissions demonstration 
required by Sec.  63.670(h) of this chapter, as applicable; and all 
periods during the

[[Page 43096]]

compliance determination when the pilot flame or flare flame is absent.
    (g) For each maintenance vent opening subject to the requirements 
of Sec.  60.612a(c), you must keep the applicable records specified in 
paragraphs (g)(1) through (5) of this section.
    (1) You must maintain standard site procedures used to deinventory 
equipment for safety purposes (e.g., hot work or vessel entry 
procedures) to document the procedures used to meet the requirements in 
Sec.  60.612a(c). The current copy of the procedures must be retained 
and available on-site at all times. Previous versions of the standard 
site procedures, as applicable, must be retained for five years.
    (2) If complying with the requirements of Sec.  60.612a(c)(1)(i), 
and the lower explosive limit at the time of the vessel opening exceeds 
10 percent, identification of the maintenance vent, the process units 
or equipment associated with the maintenance vent, the date of 
maintenance vent opening, and the lower explosive limit at the time of 
the vessel opening.
    (3) If complying with the requirements of Sec.  60.612a(c)(1)(ii), 
and either the vessel pressure at the time of the vessel opening 
exceeds 5 psig or the lower explosive limit at the time of the active 
purging was initiated exceeds 10 percent, identification of the 
maintenance vent, the process units or equipment associated with the 
maintenance vent, the date of maintenance vent opening, the pressure of 
the vessel or equipment at the time of discharge to the atmosphere and, 
if applicable, the lower explosive limit of the vapors in the equipment 
when active purging was initiated.
    (4) If complying with the requirements of Sec.  60.612a(c)(1)(iii), 
records of the estimating procedures used to determine the total 
quantity of VOC in the equipment and the type and size limits of 
equipment that contain less than 50 pounds of VOC at the time of 
maintenance vent opening. For each maintenance vent opening that 
contains greater than 50 pounds of VOC for which the deinventory 
procedures specified in paragraph (g)(1) of this section are not 
followed or for which the equipment opened exceeds the type and size 
limits established in the records specified in this paragraph (g)(4), 
records that identify the maintenance vent, the process units or 
equipment associated with the maintenance vent, the date of maintenance 
vent opening, and records used to estimate the total quantity of VOC in 
the equipment at the time the maintenance vent was opened to the 
atmosphere.
    (5) If complying with the requirements of Sec.  60.612a(c)(1)(iv), 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, records documenting actions taken 
to comply with other applicable alternatives and why utilization of 
this alternative was required, the date of maintenance vent opening, 
the equipment pressure and lower explosive limit of the vapors in the 
equipment at the time of discharge, an indication of whether active 
purging was performed and the pressure of the equipment during the 
installation or removal of the blind if active purging was used, the 
duration the maintenance vent was open during the blind installation or 
removal process, and records used to estimate the total quantity of VOC 
in the equipment at the time the maintenance vent was opened to the 
atmosphere for each applicable maintenance vent opening.
    (h) If you seek to comply with the requirements of this subpart by 
complying with the flow rate cutoff in Sec.  60.610a(c)(1) you must 
keep up-to-date, readily accessible records to indicate that the vent 
stream flow rate is less than 0.001 lb/hr, and of any change in 
equipment or process operation that increases the operating vent stream 
flow rate, including a measurement of the new vent stream flow rate.
    (i) You must submit to the Administrator semiannual reports of the 
information specified in paragraphs (i)(1) through (7) of this section. 
You are exempt from the reporting requirements specified in Sec.  
60.7(c). If there are no exceedances, periods, or events specified in 
paragraphs (i)(1) through (7) of this section that occurred during the 
reporting period, then you must include a statement in your report that 
no exceedances, periods, and events specified in paragraphs (i)(1) 
through (7) of this section occurred during the reporting period. The 
initial report must be submitted within 6 months after the initial 
start-up-date. On and after July 15, 2024 or once the report template 
for this subpart has been available on the Compliance and Emissions 
Data Reporting Interface (CEDRI) website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 year, whichever date is 
later, you must submit all subsequent reports using the appropriate 
electronic report template on the CEDRI website for this subpart and 
following the procedure specified in paragraph (j) of this section. The 
date report templates become available will be listed on the CEDRI 
website. Unless the Administrator or delegated state agency or other 
authority has approved a different schedule for submission of reports, 
the report must be submitted by the deadline specified in this subpart, 
regardless of the method in which the report is submitted. All 
semiannual reports must include the following general information: 
company name, address (including county), and beginning and ending 
dates of the reporting period.
    (1) Exceedances of monitored parameters recorded under paragraph 
(c) of this section. For each exceedance, the report must include a 
list of the affected facilities or equipment, the monitored parameter 
that was exceeded, the start date and time of the exceedance, the 
duration (in hours) of the exceedance, an estimate of the quantity in 
pounds of each regulated pollutant emitted over any emission limit, a 
description of the method used to estimate the emissions, the cause of 
the exceedance (including unknown cause, if applicable), as applicable, 
and the corrective action taken.
    (2) All periods recorded under paragraph (d) of this section when 
the vent stream is diverted from the control device or recovery device, 
or has no flow rate, including the information specified in paragraphs 
(i)(2)(i) through (iii) of this section.
    (i) For periods when the flow indicator is not operating, the 
identification of the flow indicator and report the start date, start 
time, and duration in hours.
    (ii) For each flow event from a relief valve discharge subject to 
the requirements in Sec.  60.612a(b)(1), the semiannual report must 
include the identification of the relief valve, the start date, start 
time, duration in hours, estimate of the volume of gas in standard 
cubic feet, the concentration of TOC in the gas in parts per million by 
volume and the resulting mass emissions of TOC in pounds that released 
to the atmosphere.
    (iii) For each flow event from a bypass line subject to the 
requirements in Sec.  60.612a(b)(2) and Sec.  620a(e)(2), the 
semiannual report must include the identification of the bypass line, 
the start date, start time, duration in hours, estimate of the volume 
of gas in standard cubic feet, the concentration of TOC in the gas in 
parts per million by volume and the resulting mass emissions of TOC in 
pounds that bypass a control device or recovery device.
    (3) All periods when a boiler or process heater was not operating 
(considering the records recorded under paragraph (e) of this section), 
including

[[Page 43097]]

the start date, start time, and duration in hours of each period.
    (4) For each flare subject to the requirements in Sec.  60.619a, 
the semiannual report must include an identification of the flare and 
the items specified in Sec.  60.619a(l)(2).
    (5) For each closed vent system subject to the requirements in 
Sec.  60.620a, the semiannual report must include an identification of 
the closed vent system and the items specified in Sec.  60.620a(i).
    (6) Exceedances of the emission standard in table 1 to this subpart 
as indicated by a 3-hour average of the TOC CEMS and recorded under 
paragraph (c) of this section. For each exceedance, the report must 
include a list of the affected facilities or equipment, the start date 
and time of the exceedance, the duration (in hours) of the exceedance, 
an estimate of the quantity in pounds of each regulated pollutant 
emitted over the emission limit, a description of the method used to 
estimate the emissions, the cause of the exceedance (including unknown 
cause, if applicable), as applicable, and the corrective action taken.
    (7) Periods when the TOC CEMS was inoperative. For each period, the 
report must include a list of the affected facilities or equipment, the 
start date and time of the period, the duration (in hours) of the 
period, the cause of the inoperability (including unknown cause, if 
applicable), as applicable, and the corrective action taken.
    (8) Any change in equipment or process operation that increases the 
operating vent stream flow rate above the low flow exemption level in 
Sec.  60.610a(c)(1), including a measurement of the new vent stream 
flow rate, as recorded under paragraph (h) of this section. These must 
be reported as soon as possible after the change and no later than 180 
days after the change. These reports may be submitted either in 
conjunction with semiannual reports or as a single separate report. A 
performance test must be completed with the same time period to verify 
the recalculated flow value. The performance test is subject to the 
requirements of Sec.  60.8 of the General Provisions and must be 
submitted according to paragraph (b)(1) of this section. Unless the 
facility qualifies for an exemption under Sec.  60.610a(c), the 
facility must begin compliance with the requirements set forth in Sec.  
60.612a.
    (j) If you are required to submit notifications or reports 
following the procedure specified in this paragraph (j), you must 
submit notifications or reports to the EPA via the CEDRI, which can be 
accessed through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/). The EPA will make all the information submitted through 
CEDRI available to the public without further notice to you. Do not use 
CEDRI to submit information you claim as CBI. Although we do not expect 
persons to assert a claim of CBI, if you wish to assert a CBI claim for 
some of the information in the report or notification, you must submit 
a complete file in the format specified in this subpart, including 
information claimed to be CBI, to the EPA following the procedures in 
paragraphs (j)(1) and (2) of this section. Clearly mark the part or all 
of the information that you claim to be CBI. Information not marked as 
CBI may be authorized for public release without prior notice. 
Information marked as CBI will not be disclosed except in accordance 
with procedures set forth in 40 CFR part 2. All CBI claims must be 
asserted at the time of submission. Anything submitted using CEDRI 
cannot later be claimed CBI. Furthermore, under CAA section 114(c), 
emissions data is not entitled to confidential treatment, and the EPA 
is required to make emissions data available to the public. Thus, 
emissions data will not be protected as CBI and will be made publicly 
available. You must submit the same file submitted to the CBI office 
with the CBI omitted to the EPA via the EPA's CDX as described earlier 
in this paragraph (j).
    (1) The preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
[email protected], and as described above, should include clear CBI 
markings. ERT files should be flagged to the attention of the Group 
Leader, Measurement Policy Group; all other files should be flagged to 
the attention of the SOCMI NSPS Sector Lead. If assistance is needed 
with submitting large electronic files that exceed the file size limit 
for email attachments, and if you do not have your own file sharing 
service, please email [email protected] to request a file transfer link.
    (2) If you cannot transmit the file electronically, you may send 
CBI information through the postal service to the following address: 
OAQPS Document Control Officer (C404-02), OAQPS, U.S. Environmental 
Protection Agency, 109 T.W. Alexander Drive, P.O. Box 12055, Research 
Triangle Park, North Carolina 27711. ERT files should be sent to the 
attention of the Group Leader, Measurement Policy Group, and all other 
files should be sent to the attention of the SOCMI NSPS Sector Lead. 
The mailed CBI material should be double wrapped and clearly marked. 
Any CBI markings should not show through the outer envelope.
    (k) If you are required to electronically submit notifications or 
reports through CEDRI in the EPA's CDX, you may assert a claim of EPA 
system outage for failure to timely comply with the electronic 
submittal requirement. To assert a claim of EPA system outage, you must 
meet the requirements outlined in paragraphs (k)(1) through (7) of this 
section.
    (1) You must have been or will be precluded from accessing CEDRI 
and submitting a required report within the time prescribed due to an 
outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (5) You must provide to the Administrator a written description 
identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (l) If you are required to electronically submit notifications or 
reports through CEDRI in the EPA's CDX, you may assert a claim of force 
majeure for failure to timely comply with the electronic submittal 
requirement. To assert a claim of force majeure, you must meet the 
requirements outlined in paragraphs (l)(1) through (5) of this section.
    (1) You may submit a claim if a force majeure event is about to 
occur, occurs,

[[Page 43098]]

or has occurred or there are lingering effects from such an event 
within the period of time beginning five business days prior to the 
date the submission is due. For the purposes of this section, a force 
majeure event is defined as an event that will be or has been caused by 
circumstances beyond the control of the affected facility, its 
contractors, or any entity controlled by the affected facility that 
prevents you from complying with the requirement to submit a report 
electronically within the time period prescribed. Examples of such 
events are acts of nature (e.g., hurricanes, earthquakes, or floods), 
acts of war or terrorism, or equipment failure or safety hazard beyond 
the control of the affected facility (e.g., large scale power outage).
    (2) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (3) You must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.
    (m) The requirements of paragraph (i) of this section remain in 
force until and unless EPA, in delegating enforcement authority to a 
State under section 111(c) of the Act, approves reporting requirements 
or an alternative means of compliance surveillance adopted by such 
State. In that event, affected sources within the State will be 
relieved of the obligation to comply with paragraph (i) of this 
section, provided that they comply with the requirements established by 
the State. The EPA will not approve a waiver of electronic reporting to 
the EPA in delegating enforcement authority. Thus, electronic reporting 
to the EPA cannot be waived, and as such, the provisions of this 
paragraph cannot be used to relieve owners or operators of affected 
facilities of the requirement to submit the electronic reports required 
in this section to the EPA.
    (n) If you seek to demonstrate compliance with Sec.  60.610(c)(1), 
then you must submit to the Administrator, following the procedures in 
paragraph (b)(1) of this section, an initial report including a flow 
rate measurement using the test methods specified in Sec.  60.614a.
    (o) The Administrator will specify appropriate reporting and 
recordkeeping requirements where the owner or operator of an affected 
facility seeks to demonstrate compliance with the standards specified 
under Sec.  60.612a other than as provided under Sec.  60.613a.
    (p) Any records required to be maintained by this subpart that are 
submitted electronically via the EPA's CEDRI may be maintained in 
electronic format. This ability to maintain electronic copies does not 
affect the requirement for facilities to make records, data, and 
reports available upon request to a delegated air agency or the EPA as 
part of an on-site compliance evaluation.


Sec.  60.616a  What do the terms associated with reconstruction mean 
for this subpart?

    For purposes of this subpart ``fixed capital cost of the new 
components,'' as used in Sec.  60.15, includes the fixed capital cost 
of all depreciable components which are or will be replaced pursuant to 
all continuous programs of component replacement which are commenced 
within any 2-year period following April 25, 2023. For purposes of this 
section, ``commenced'' means that you have undertaken a continuous 
program of component replacement or that you have entered into a 
contractual obligation to undertake and complete, within a reasonable 
time, a continuous program of component replacement.


Sec.  60.617a  What are the chemicals that I must produce to be 
affected by subpart IIIa?

------------------------------------------------------------------------
                       Chemical name                           CAS No.*
------------------------------------------------------------------------
Acetaldehyde...............................................      75-07-0
Acetic acid................................................      64-19-7
Acetone....................................................      67-64-1
Acetonitrile...............................................      75-05-8
Acetophenone...............................................      98-86-2
Acrolein...................................................     107-02-8
Acrylic acid...............................................      79-10-7
Acrylonitrile..............................................     107-13-1
Anthraquinone..............................................      84-65-1
Benzaldehyde...............................................     100-52-7
Benzoic acid, tech.........................................      65-85-0
1,3-Butadiene..............................................     106-99-0
p-t-Butyl benzoic acid.....................................      98-73-7
N-Butyric acid.............................................     107-92-6
Crotonic acid..............................................    3724-65-0
Cumene hydroperoxide.......................................      80-15-9
Cyclohexanol...............................................     108-93-0
Cyclohexanone..............................................     108-94-1
Dimethyl terephthalate.....................................     120-61-6
Ethylene dichloride........................................     107-06-2
Ethylene oxide.............................................      75-21-8
Formaldehyde...............................................      50-00-0
Formic acid................................................      64-18-6
Glyoxal....................................................     107-22-2
Hydrogen cyanide...........................................      74-90-8
Isobutyric acid............................................      79-31-2
Isophthalic acid...........................................     121-91-5
Maleic anhydride...........................................     108-31-6
Methyl ethyl ketone........................................      78-93-3
a-Methyl styrene...........................................      98-83-9
Phenol.....................................................     108-95-2
Phthalic anhydride.........................................      85-44-9
Propionic acid.............................................      79-09-4
Propylene oxide............................................      75-56-9
Styrene....................................................     100-42-5
Terephthalic acid..........................................     100-21-0
------------------------------------------------------------------------
* CAS numbers refer to the Chemical Abstracts Registry numbers assigned
  to specific chemicals, isomers, or mixtures of chemicals. Some isomers
  or mixtures that are covered by the standards do not have CAS numbers
  assigned to them. The standards apply to all of the chemicals listed,
  whether CAS numbers have been assigned or not.

Sec.  60.618a  [Reserved]


Sec.  60.619a  What are my requirements if I use a flare to comply with 
this subpart?

    (a) If you use a flare to comply with the TOC emission standard 
specified in Table 1 to this subpart, then you must meet the applicable 
requirements for flares as specified in Sec. Sec.  63.670 and 63.671 of 
this chapter, including the provisions in tables 12 and 13 to part 63, 
subpart CC, of this chapter, except as specified in paragraphs (b) 
through (o) of this section. This requirement also applies to any flare 
using fuel gas from a fuel gas system, of which 50 percent or more of 
the fuel gas is derived from an affected facility, as determined on an 
annual average basis. For purposes of compliance with this paragraph 
(a), the following terms are defined in Sec.  63.641 of this chapter: 
Assist air, assist steam, center steam, combustion zone, combustion 
zone gas, flare, flare purge gas, flare supplemental gas, flare sweep 
gas, flare vent gas, lower steam, net heating value, perimeter assist 
air, pilot gas, premix assist air, total steam, and upper steam.
    (b) When determining compliance with the pilot flame requirements 
specified in Sec.  63.670(b) and (g) of this chapter, substitute 
``pilot flame or flare flame'' for each occurrence of ``pilot flame.''
    (c) When determining compliance with the flare tip velocity and 
combustion zone operating limits specified in Sec.  63.670(d) and (e) 
of this chapter, the requirement effectively applies starting with the 
15-minute

[[Page 43099]]

block that includes a full 15 minutes of the flaring event. You are 
required to demonstrate compliance with the velocity and NHVcz 
requirements starting with the block that contains the fifteenth minute 
of a flaring event. You are not required to demonstrate compliance for 
the previous 15-minute block in which the event started and contained 
only a fraction of flow.
    (d) Instead of complying with Sec.  63.670(o)(2)(i) of this 
chapter, you must develop and implement the flare management plan no 
later than startup for a new flare that commenced construction on or 
after April 25, 2023.
    (e) Instead of complying with Sec.  63.670(o)(2)(iii) of this 
chapter, if required to develop a flare management plan and submit it 
to the Administrator, then you must also submit all versions of the 
plan in portable document format (PDF) following the procedures 
specified in Sec.  60.615a(j).
    (f) Section 63.670(o)(3)(ii) of this chapter and all references to 
it do not apply. Instead, you must comply with the maximum flare tip 
velocity operating limit at all times.
    (g) Substitute ``affected facility'' for each occurrence of 
``petroleum refinery.''
    (h) Each occurrence of ``refinery'' does not apply.
    (i) If a pressure-assisted multi-point flare is used as a control 
device, then you must meet the following conditions:
    (1) You are not required to comply with the flare tip velocity 
requirements in of Sec.  63.670(d) and (k) of this chapter;
    (2) The NHVcz for pressure-assisted mulit-point flares is 800 Btu/
scf;
    (3) You must determine the 15-minute block average NHVvg using only 
the direct calculation method specified in in Sec.  63.670 (l)(5)(ii) 
of this chapter;
    (4) Instead of complying with Sec.  63.670(b) and (g) of this 
chapter, if a pressure-assisted multi-point flare uses cross-lighting 
on a stage of burners rather than having an individual pilot flame on 
each burner, then you must operate each stage of the pressure-assisted 
multi-point flare with a flame present at all times when regulated 
material is routed to that stage of burners. Each stage of burners that 
cross-lights in the pressure-assisted multi-point flare must have at 
least two pilots with at least one continuously lit and capable of 
igniting all regulated material that is routed to that stage of 
burners. Each 15-minute block during which there is at least one minute 
where no pilot flame is present on a stage of burners when regulated 
material is routed to the flare is a deviation of the standard. 
Deviations in different 15-minute blocks from the same event are 
considered separate deviations. The pilot flame(s) on each stage of 
burners that use cross-lighting must be continuously monitored by a 
thermocouple or any other equivalent device used to detect the presence 
of a flame;
    (5) Unless you choose to conduct a cross-light performance 
demonstration as specified in this paragraph (i)(5), you must ensure 
that if a stage of burners on the flare uses cross-lighting, that the 
distance between any two burners in series on that stage is no more 
than 6 feet when measured from the center of one burner to the next 
burner. A distance greater than 6 feet between any two burners in 
series may be used provided you conduct a performance demonstration 
that confirms the pressure-assisted multi-point flare will cross-light 
a minimum of three burners and the spacing between the burners and 
location of the pilot flame must be representative of the projected 
installation. The compliance demonstration must be approved by the 
permitting authority and a copy of this approval must be maintained 
onsite. The compliance demonstration report must include: a protocol 
describing the test methodology used, associated test method QA/QC 
parameters, the waste gas composition and NHVcz of the gas tested, the 
velocity of the waste gas tested, the pressure-assisted multi-point 
flare burner tip pressure, the time, length, and duration of the test, 
records of whether a successful cross-light was observed over all of 
the burners and the length of time it took for the burners to cross-
light, records of maintaining a stable flame after a successful cross-
light and the duration for which this was observed, records of any 
smoking events during the cross-light, waste gas temperature, 
meteorological conditions (e.g., ambient temperature, barometric 
pressure, wind speed and direction, and relative humidity), and whether 
there were any observed flare flameouts; and
    (6) You must install and operate pressure monitor(s) on the main 
flare header, as well as a valve position indicator monitoring system 
for each staging valve to ensure that the flare operates within the 
proper range of conditions as specified by the manufacturer. The 
pressure monitor must meet the requirements in table 13 to part 63, 
subpart CC of this chapter.
    (7) If a pressure-assisted multi-point flare is operating under the 
requirements of an approved alternative means of emission limitations, 
you must either continue to comply with the terms of the alternative 
means of emission limitations or comply with the provisions in 
paragraphs (i)(1) through (6) of this section.
    (j) If you choose to determine compositional analysis for net 
heating value with a continuous process mass spectrometer, then you 
must comply with the requirements specified in paragraphs (j)(1) 
through (7) of this section.
    (1) You must meet the requirements in Sec.  63.671(e)(2) of this 
chapter. You may augment the minimum list of calibration gas components 
found in Sec.  63.671(e)(2) with compounds found during a pre-survey or 
known to be in the gas through process knowledge.
    (2) Calibration gas cylinders must be certified to an accuracy of 2 
percent and traceable to National Institute of Standards and Technology 
(NIST) standards.
    (3) For unknown gas components that have similar analytical mass 
fragments to calibration compounds, you may report the unknowns as an 
increase in the overlapped calibration gas compound. For unknown 
compounds that produce mass fragments that do not overlap calibration 
compounds, you may use the response factor for the nearest molecular 
weight hydrocarbon in the calibration mix to quantify the unknown 
component's NHVvg.
    (4) You may use the response factor for n-pentane to quantify any 
unknown components detected with a higher molecular weight than n-
pentane.
    (5) You must perform an initial calibration to identify mass 
fragment overlap and response factors for the target compounds.
    (6) You must meet applicable requirements in Performance 
Specification 9 of appendix B of this part, for continuous monitoring 
system acceptance including, but not limited to, performing an initial 
multi-point calibration check at three concentrations following the 
procedure in section 10.1 and performing the periodic calibration 
requirements listed for gas chromatographs in table 13 to part 63, 
subpart CC of this chapter, for the process mass spectrometer. You may 
use the alternative sampling line temperature allowed under Net Heating 
Value by Gas Chromatograph in table 13 to part 63, subpart CC.
    (7) The average instrument calibration error (CE) for each 
calibration compound at any calibration concentration must not differ 
by more than 10 percent from the certified cylinder gas value. The CE 
for each

[[Page 43100]]

component in the calibration blend must be calculated using equation 1 
to this paragraph (j)(7).
Equation 1 to Paragraph (j)(7)
[GRAPHIC] [TIFF OMITTED] TR16MY24.033

Where:

Cm = Average instrument response (ppm)
Ca = Certified cylinder gas value (ppm)

    (k) If you use a gas chromatograph or mass spectrometer for 
compositional analysis for net heating value, then you may choose to 
use the CE of NHVmeasured versus the cylinder tag value NHV 
as the measure of agreement for daily calibration and quarterly audits 
in lieu of determining the compound-specific CE. The CE for NHV at any 
calibration level must not differ by more than 10 percent from the 
certified cylinder gas value. The CE must be calculated using equation 
2 to this paragraph (k).
Equation 2 to Paragraph (k)
[GRAPHIC] [TIFF OMITTED] TR16MY24.034

Where:

NHVmeasured = Average instrument response (Btu/scf)
NHVa = Certified cylinder gas value (Btu/scf)

    (l) Instead of complying with Sec.  63.670(q) of this chapter, you 
must comply with the reporting requirements specified in paragraphs 
(l)(1) and (2) of this section.
    (1) The notification requirements specified in Sec.  60.615a(a).
    (2) The semiannual report specified in Sec.  60.615a(i)(4) must 
include the items specified in paragraphs (l)(2)(i) through (vi) of 
this section.
    (i) Records as specified in paragraph (m)(1) of this section for 
each 15-minute block during which there was at least one minute when 
regulated material is routed to a flare and no pilot flame or flare 
flame is present. Include the start and stop time and date of each 15-
minute block.
    (ii) Visible emission records as specified in paragraph (m)(2)(iv) 
of this section for each period of 2 consecutive hours during which 
visible emissions exceeded a total of 5 minutes.
    (iii) The periods specified in paragraph (m)(6) of this section. 
Indicate the date and start and end times for each period, and the net 
heating value operating parameter(s) determined following the methods 
in Sec.  63.670(k) through (n) of part 63, subpart CC of this chapter 
as applicable.
    (iv) For flaring events meeting the criteria in Sec.  63.670(o)(3) 
of this chapter and paragraph (f) of this section:
    (A) The start and stop time and date of the flaring event.
    (B) The length of time in minutes for which emissions were visible 
from the flare during the event.
    (C) For steam-assisted, air-assisted, and non-assisted flares, the 
start date, start time, and duration in minutes for periods of time 
that the flare tip velocity exceeds the maximum flare tip velocity 
determined using the methods in Sec.  63.670(d)(2) of this chapter and 
the maximum 15-minute block average flare tip velocity in ft/sec 
recorded during the event.
    (D) Results of the root cause and corrective actions analysis 
completed during the reporting period, including the corrective actions 
implemented during the reporting period and, if applicable, the 
implementation schedule for planned corrective actions to be 
implemented subsequent to the reporting period.
    (v) For pressure-assisted multi-point flares, the periods of time 
when the pressure monitor(s) on the main flare header show the burners 
operating outside the range of the manufacturer's specifications. 
Indicate the date and start and end times for each period.
    (vi) For pressure-assisted multi-point flares, the periods of time 
when the staging valve position indicator monitoring system indicates a 
stage should not be in operation and is or when a stage should be in 
operation and is not. Indicate the date and start and end times for 
each period.
    (m) Instead of complying with Sec.  63.670(p) of this chapter, you 
must keep the flare monitoring records specified in paragraphs (m)(1) 
through (14) of this section.
    (1) Retain records of the output of the monitoring device used to 
detect the presence of a pilot flame or flare flame as required in 
Sec.  63.670(b) of this chapter and the presence of a pilot flame as 
required in paragraph (i)(4) of this section for a minimum of 2 years. 
Retain records of each 15-minute block during which there was at least 
one minute that no pilot flame or flare flame is present when regulated 
material is routed to a flare for a minimum of 5 years. For a pressure-
assisted multi-point flare that uses cross-lighting, retain records of 
each 15-minute block during which there was at least one minute that no 
pilot flame is present on each stage when regulated material is routed 
to a flare for a minimum of 5 years. You may reduce the collected 
minute-by-minute data to a 15-minute block basis with an indication of 
whether there was at least one minute where no pilot flame or flare 
flame was present.
    (2) Retain records of daily visible emissions observations as 
specified in paragraphs (m)(2)(i) through (iv) of this section, as 
applicable, for a minimum of 3 years.
    (i) To determine when visible emissions observations are required, 
the record must identify all periods when regulated material is vented 
to the flare.
    (ii) If visible emissions observations are performed using Method 
22 of appendix A-7 of this part, then the record must identify whether 
the visible emissions observation was performed, the results of each 
observation, total duration of observed visible emissions, and whether 
it was a 5-minute or 2-hour observation. Record the date and start time 
of each visible emissions observation.
    (iii) If a video surveillance camera is used pursuant to Sec.  
63.670(h)(2) of this chapter, then the record must include all video 
surveillance images recorded, with time and date stamps.
    (iv) For each 2-hour period for which visible emissions are 
observed for more than 5 minutes in 2 consecutive hours, then the 
record must include the date and start and end time of the 2-hour 
period and an estimate of the cumulative number of minutes in the 2 
hour period for which emissions were visible.
    (3) The 15-minute block average cumulative flows for flare vent gas 
and, if applicable, total steam, perimeter assist air, and premix 
assist air specified to be monitored under Sec.  63.670(i) of this 
chapter, along with the date and time

[[Page 43101]]

interval for the 15-minute block. If multiple monitoring locations are 
used to determine cumulative vent gas flow, total steam, perimeter 
assist air, and premix assist air, then retain records of the 15-minute 
block average flows for each monitoring location for a minimum of 2 
years and retain the 15-minute block average cumulative flows that are 
used in subsequent calculations for a minimum of 5 years. If pressure 
and temperature monitoring is used, then retain records of the 15-
minute block average temperature, pressure, and molecular weight of the 
flare vent gas or assist gas stream for each measurement location used 
to determine the 15-minute block average cumulative flows for a minimum 
of 2 years, and retain the 15-minute block average cumulative flows 
that are used in subsequent calculations for a minimum of 5 years.
    (4) The flare vent gas compositions specified to be monitored under 
Sec.  63.670(j) of this chapter. Retain records of individual component 
concentrations from each compositional analysis for a minimum of 2 
years. If an NHVvg analyzer is used, retain records of the 15-minute 
block average values for a minimum of 5 years.
    (5) Each 15-minute block average operating parameter calculated 
following the methods specified in Sec.  63.670(k) through (n) of this 
chapter, as applicable.
    (6) All periods during which operating values are outside of the 
applicable operating limits specified in Sec.  63.670(d) through (f) of 
this chapter and paragraph (i) of this section when regulated material 
is being routed to the flare.
    (7) All periods during which you do not perform flare monitoring 
according to the procedures in Sec.  63.670(g) through (j) of this 
chapter.
    (8) For pressure-assisted multi-point flares, if a stage of burners 
on the flare uses cross-lighting, then a record of any changes made to 
the distance between burners.
    (9) For pressure-assisted multi-point flares, all periods when the 
pressure monitor(s) on the main flare header show burners are operating 
outside the range of the manufacturer's specifications. Indicate the 
date and time for each period, the pressure measurement, the stage(s) 
and number of burners affected, and the range of manufacturer's 
specifications.
    (10) For pressure-assisted multi-point flares, all periods when the 
staging valve position indicator monitoring system indicates a stage of 
the pressure-assisted multi-point flare should not be in operation and 
when a stage of the pressure-assisted multi-point flare should be in 
operation and is not. Indicate the date and time for each period, 
whether the stage was supposed to be open, but was closed or vice 
versa, and the stage(s) and number of burners affected.
    (11) Records of periods when there is flow of vent gas to the 
flare, but when there is no flow of regulated material to the flare, 
including the start and stop time and dates of periods of no regulated 
material flow.
    (12) Records when the flow of vent gas exceeds the smokeless 
capacity of the flare, including start and stop time and dates of the 
flaring event.
    (13) Records of the root cause analysis and corrective action 
analysis conducted as required in Sec.  63.670(o)(3) of this chapter 
and paragraph (f) of this section, including an identification of the 
affected flare, the date and duration of the event, a statement noting 
whether the event resulted from the same root cause(s) identified in a 
previous analysis and either a description of the recommended 
corrective action(s) or an explanation of why corrective action is not 
necessary under Sec.  63.670(o)(5)(i) of this chapter.
    (14) For any corrective action analysis for which implementation of 
corrective actions are required in Sec.  63.670(o)(5) of this chapter, 
a description of the corrective action(s) completed within the first 45 
days following the discharge and, for action(s) not already completed, 
a schedule for implementation, including proposed commencement and 
completion dates.
    (n) You may elect to comply with the alternative means of emissions 
limitation requirements specified in paragraph (r) of Sec.  63.670 of 
this chapter in lieu of the requirements in Sec.  63.670(d) through (f) 
of this chapter, as applicable. However, instead of complying with 
Sec.  63.670(r)(3)(iii) of this chapter, you must also submit the 
alternative means of emissions limitation request to the following 
address: U.S. Environmental Protection Agency, Office of Air Quality 
Planning and Standards, Sector Policies and Programs Division, U.S. EPA 
Mailroom (C404-02), Attention: SOCMI NSPS Sector Lead, 4930 Old Page 
Rd., Durham, NC 27703.
    (o) The referenced provisions specified in paragraphs (o)(1) 
through (4) of this section do not apply when demonstrating compliance 
with this section.
    (1) Section 63.670(o)(4)(iv) of this chapter.
    (2) The last sentence of Sec.  63.670(o)(6) of this chapter.
    (3) The phrase ``that were not caused by a force majeure event'' in 
Sec.  63.670(o)(7)(ii) of this chapter.
    (4) The phrase ``that were not caused by a force majeure event'' in 
Sec.  63.670(o)(7)(iv) of this chapter.


Sec.  60.620a  What are my requirements for closed vent systems?

    (a) Except as provided in paragraphs (f) and (g) of this section, 
you must inspect each closed vent system according to the procedures 
and schedule specified in paragraphs (a)(1) through (3) of this 
section.
    (1) Conduct an initial inspection according to the procedures in 
paragraph (b) of this section unless the closed vent system is operated 
and maintained under negative pressure,
    (2) Conduct annual inspections according to the procedures in 
paragraph (b) of this section unless the closed vent system is operated 
and maintained under negative pressure, and
    (3) Conduct annual inspections for visible, audible, or olfactory 
indications of leaks.
    (b) You must inspect each closed vent system according to the 
procedures specified in paragraphs (b)(1) through (6) of this section.
    (1) Inspections must be conducted in accordance with Method 21 of 
appendix A of this part.
    (2)(i) Except as provided in paragraph (b)(2)(ii) of this section, 
the detection instrument must meet the performance criteria of Method 
21 of appendix A of this part, except the instrument response factor 
criteria in section 3.1.2(a) of Method 21 must be for the average 
composition of the process fluid not each individual volatile organic 
compound in the stream. For process streams that contain nitrogen, air, 
or other inerts which are not organic hazardous air pollutants or 
volatile organic compounds, the average stream response factor must be 
calculated on an inert-free basis.
    (ii) If no instrument is available at the plant site that will meet 
the performance criteria specified in paragraph (b)(2)(i) of this 
section, the instrument readings may be adjusted by multiplying by the 
average response factor of the process fluid, calculated on an inert-
free basis as described in paragraph (b)(2)(i) of this section.
    (3) The detection instrument must be calibrated before use on each 
day of its use by the procedures specified in Method 21 of appendix A 
of this part.
    (4) Calibration gases must be as follows:
    (i) Zero air (less than 10 parts per million hydrocarbon in air); 
and

[[Page 43102]]

    (ii) Mixtures of methane in air at a concentration less than 2,000 
parts per million. A calibration gas other than methane in air may be 
used if the instrument does not respond to methane or if the instrument 
does not meet the performance criteria specified in paragraph (b)(2)(i) 
of this section. In such cases, the calibration gas may be a mixture of 
one or more of the compounds to be measured in air.
    (5) You may elect to adjust or not adjust instrument readings for 
background. If you elect to not adjust readings for background, all 
such instrument readings must be compared directly to the applicable 
leak definition to determine whether there is a leak.
    (6) If you elect to adjust instrument readings for background, you 
must determine the background concentration using Method 21 of appendix 
A of this part. After monitoring each potential leak interface, 
subtract the background reading from the maximum concentration 
indicated by the instrument. The arithmetic difference between the 
maximum concentration indicated by the instrument and the background 
level must be compared with 500 parts per million for determining 
compliance.
    (c) Leaks, as indicated by an instrument reading greater than 500 
parts per million above background or by visual, audio, or olfactory 
inspections, must be repaired as soon as practicable, except as 
provided in paragraph (d) of this section.
    (1) A first attempt at repair must be made no later than 5 calendar 
days after the leak is detected.
    (2) Repair must be completed no later than 15 calendar days after 
the leak is detected.
    (d) Delay of repair of a closed vent system for which leaks have 
been detected is allowed if the repair is technically infeasible 
without a shutdown, as defined in Sec.  60.2, or if you determine that 
emissions resulting from immediate repair would be greater than the 
fugitive emissions likely to result from delay of repair. Repair of 
such equipment must be complete by the end of the next shutdown.
    (e) For each closed vent system that contains bypass lines that 
could divert a vent stream away from the control device and to the 
atmosphere, you must comply with the provisions of either paragraph 
(e)(1) or (2), except as specified in paragraph (e)(3) of this section.
    (1) Install, calibrate, maintain, and operate a flow indicator that 
determines whether vent stream flow is present at least once every 15 
minutes. You must keep hourly records of whether the flow indicator was 
operating and whether a diversion was detected at any time during the 
hour, as well as records of the times and durations of all periods when 
the vent stream is diverted to the atmosphere or the flow indicator is 
not operating. The flow indicator must be installed at the entrance to 
any bypass line; or
    (2) Secure the bypass line valve in the closed position with a car-
seal or a lock-and-key type configuration. A visual inspection of the 
seal or closure mechanism must be performed at least once every month 
to ensure the valve is maintained in the closed position and the vent 
stream is not diverted through the bypass line.
    (3) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in Sec.  60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as Sec.  60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (e).
    (f) Any parts of the closed vent system that are designated, as 
described in paragraph (h)(1) of this section, as unsafe to inspect are 
exempt from the inspection requirements of paragraphs (a)(1) and (2) of 
this section if:
    (1) You determine that the equipment is unsafe to inspect because 
inspecting personnel would be exposed to an imminent or potential 
danger as a consequence of complying with paragraphs (a)(1) and (2) of 
this section; and
    (2) You have a written plan that requires inspection of the 
equipment as frequently as practicable during safe-to-inspect times.
    (g) Any parts of the closed vent system are designated, as 
described in paragraph (h)(2) of this section, as difficult to inspect 
are exempt from the inspection requirements of paragraphs (a)(1) and 
(2) of this section if:
    (1) You determine that the equipment cannot be inspected without 
elevating the inspecting personnel more than 2 meters above a support 
surface; and
    (2) You have a written plan that requires inspection of the 
equipment at least once every 5 years.
    (h) You must record the information specified in paragraphs (h)(1) 
through (5) of this section.
    (1) Identification of all parts of the closed vent system that are 
designated as unsafe to inspect, an explanation of why the equipment is 
unsafe to inspect, and the plan for inspecting the equipment.
    (2) Identification of all parts of the closed vent system that are 
designated as difficult to inspect, an explanation of why the equipment 
is difficult to inspect, and the plan for inspecting the equipment.
    (3) For each closed vent system that contains bypass lines that 
could divert a vent stream away from the control device and to the 
atmosphere, you must keep a record of the information specified in 
either paragraph (h)(3)(i) or (ii) of this section in addition to the 
information specified in paragraph (h)(3)(iii) of this section.
    (i) Hourly records of whether the flow indicator specified under 
paragraph (e)(1) of this section was operating and whether a diversion 
was detected at any time during the hour, as well as records of the 
times of all periods when the vent stream is diverted from the control 
device or the flow indicator is not operating.
    (ii) Where a seal mechanism is used to comply with paragraph (e)(2) 
of this section, hourly records of flow are not required. In such 
cases, you must record whether the monthly visual inspection of the 
seals or closure mechanisms has been done, and you must record the 
occurrence of all periods when the seal mechanism is broken, the bypass 
line valve position has changed, or the key for a lock-and-key type 
configuration has been checked out, and records of any car-seal that 
has broken.
    (iii) For each flow event from a bypass line subject to the 
requirements in paragraph (e) of this section, you must maintain 
records sufficient to determine whether or not the detected flow 
included flow requiring control. For each flow event from a bypass line 
requiring control that is released either directly to the atmosphere or 
to a control device not meeting the requirements in this subpart, you 
must include an estimate of the volume of gas, the concentration of VOC 
in the gas and the resulting emissions of VOC that bypassed the control 
device using process knowledge and engineering estimates.
    (4) For each inspection during which a leak is detected, a record 
of the information specified in paragraphs (h)(4)(i) through (viii) of 
this section.
    (i) The instrument identification numbers; operator name or 
initials; and identification of the equipment.
    (ii) The date the leak was detected and the date of the first 
attempt to repair the leak.
    (iii) Maximum instrument reading measured by the method specified 
in paragraph (c) of this section after the leak is successfully 
repaired or determined to be nonrepairable.
    (iv) ``Repair delayed'' and the reason for the delay if a leak is 
not repaired within 15 calendar days after discovery of the leak.

[[Page 43103]]

    (v) The name, initials, or other form of identification of the 
owner or operator (or designee) whose decision it was that repair could 
not be effected without a shutdown.
    (vi) The expected date of successful repair of the leak if a leak 
is not repaired within 15 calendar days.
    (vii) Dates of shutdowns that occur while the equipment is 
unrepaired.
    (viii) The date of successful repair of the leak.
    (5) For each inspection conducted in accordance with paragraph (b) 
of this section during which no leaks are detected, a record that the 
inspection was performed, the date of the inspection, and a statement 
that no leaks were detected.
    (6) For each inspection conducted in accordance with paragraph 
(a)(3) of this section during which no leaks are detected, a record 
that the inspection was performed, the date of the inspection, and a 
statement that no leaks were detected.
    (i) The semiannual report specified in Sec.  60.615a(i)(5) must 
include the items specified in paragraphs (i)(1) through (3) of this 
section.
    (1) Reports of the times of all periods recorded under paragraph 
(h)(3)(i) of this section when the vent stream is diverted from the 
control device through a bypass line. Include the start date, start 
time, and duration in hours of each period.
    (2) Reports of all periods recorded under paragraph (h)(3)(ii) of 
this section in which the seal mechanism is broken, the bypass line 
valve position has changed, or the key to unlock the bypass line valve 
was checked out. Include the start date, start time, and duration in 
hours of each period.
    (3) For bypass lines subject to the requirements in paragraph (e) 
of this section, the semiannual reports must include the start date, 
start time, duration in hours, estimate of the volume of gas in 
standard cubic feet, the concentration of VOC in the gas in parts per 
million by volume and the resulting mass emissions of VOC in pounds 
that bypass a control device. For periods when the flow indicator is 
not operating, report the start date, start time, and duration in 
hours.

  Table 1 to Subpart IIIa of Part 60--Emission Limits and Standards for
                              Vent Streams
------------------------------------------------------------------------
             For each. . .                        You must. . .
------------------------------------------------------------------------
1. Vent stream.........................  a. Reduce emissions of TOC
                                          (minus methane and ethane) by
                                          98 weight-percent, or to a TOC
                                          (minus methane and ethane)
                                          concentration of 20 ppmv on a
                                          dry basis corrected to 3
                                          percent oxygen by venting
                                          emissions through a closed
                                          vent system to any combination
                                          of non-flare control devices
                                          and/or recovery system and
                                          meet the requirements
                                          specified in Sec.   60.613a
                                          and Sec.   60.620a; or
                                         b. Reduce emissions of TOC
                                          (minus methane and ethane) by
                                          venting emissions through a
                                          closed vent system to a flare
                                          and meet the requirements
                                          specified in Sec.   60.619a
                                          and Sec.   60.620a.
------------------------------------------------------------------------


     Table 2 to Subpart IIIa of Part 60--Monitoring Requirements for
  Complying With 98 Weight-Percent Reduction of Total Organic Compounds
         Emissions or a Limit of 20 Parts Per Million by Volume
------------------------------------------------------------------------
  Non-flare control device or recovery
                 device                     Parameters to be monitored
------------------------------------------------------------------------
1. All control and recovery devices....  a. Presence of flow diverted to
                                          the atmosphere from the
                                          control and recovery device;
                                          or
                                         b. Monthly inspections of
                                          sealed valves.
2. Absorber............................  a. Exit temperature of the
                                          absorbing liquid; and
                                         b. Exit specific gravity.
3. Boiler or process heater with a       Firebox temperature.\a\
 design heat input capacity less than
 44 megawatts and vent stream is not
 introduced with or as the primary fuel.
4. Catalytic incinerator...............  Temperature upstream and
                                          downstream of the catalyst
                                          bed.
5. Carbon adsorber, regenerative.......  a. Total regeneration stream
                                          mass or volumetric flow during
                                          carbon bed regeneration
                                          cycle(s); and
                                         b. Temperature of the carbon
                                          bed after regeneration [and
                                          within 15 minutes of
                                          completing any cooling
                                          cycle(s)].
6. Carbon adsorber, non-regenerative or  Breakthrough.
 regenerated offsite.
7. Condenser...........................  Exit (product side)
                                          temperature.
8. Scrubber for halogenated vent         a. pH of scrubber effluent; and
 streams.
                                         b. Scrubber liquid and gas flow
                                          rates.
9. Thermal incinerator.................  Firebox temperature.\a\
10. Control devices other than an        As specified by the
 incinerator, boiler, process heater,     Administrator.
 or flare; or recovery devices other
 than an absorber, condenser, or carbon
 adsorber.
------------------------------------------------------------------------
\a\ Monitor may be installed in the firebox or in the ductwork
  immediately downstream of the firebox before any substantial heat
  exchange is encountered.


[[Page 43104]]


    Table 3 to Subpart IIIa of Part 60--Operating Parameters, Operating Parameter Limits and Data Monitoring,
                                    Recordkeeping and Compliance Frequencies
----------------------------------------------------------------------------------------------------------------
                                  You must establish   And you must monitor, record, and demonstrate continuous
                                     the following          compliance using these minimum frequencies. . .
   For the operating parameter         operating     -----------------------------------------------------------
 applicable to you, as specified  parameter limit. .                                            Data averaging
         in Table 2. . .                   .           Data measurement     Data recording        period for
                                                                                                  compliance
----------------------------------------------------------------------------------------------------------------
                                                    Absorbers
----------------------------------------------------------------------------------------------------------------
1. Exit temperature of the        Maximum             Continuous........  Every 15 minutes..  3-hour block
 absorbing liquid.                 temperature.                                                average.
2. Exit specific gravity........  Exit specific       Continuous........  Every 15 minutes..  3-hour block
                                   gravity range.                                              average.
----------------------------------------------------------------------------------------------------------------
                                           Boilers or process heaters
     (with a design heat input capacity <44MW and vent stream is not introduced with or as the primary fuel)
----------------------------------------------------------------------------------------------------------------
3. Firebox temperature..........  Minimum firebox     Continuous........  Every 15 minutes..  3-hour block
                                   temperature.                                                average.
----------------------------------------------------------------------------------------------------------------
                                             Catalytic incinerators
----------------------------------------------------------------------------------------------------------------
4. Temperature in gas stream      Minimum             Continuous........  Every 15 minutes..  3-hour block
 immediately before the catalyst   temperature.                                                average.
 bed.
5. Temperature difference         Minimum             Continuous........  Every 15 minutes..  3-hour block
 between the catalyst bed inlet    temperature                                                 average.
 and the catalyst bed outlet.      difference.
----------------------------------------------------------------------------------------------------------------
                                                Carbon adsorbers
----------------------------------------------------------------------------------------------------------------
6. Total regeneration stream      Minimum mass flow   Continuously        Every 15 minutes    Total flow for
 mass flow during carbon bed       during carbon bed   during              during              each regeneration
 regeneration cycle(s).            regeneration        regeneration.       regeneration        cycle.
                                   cycle(s).                               cycle.
7. Total regeneration stream      Minimum volumetric  Continuously        Every 15 minutes    Total flow for
 volumetric flow during carbon     flow during         during              during              each regeneration
 bed regeneration cycle(s).        carbon bed          regeneration.       regeneration        cycle.
                                   regeneration                            cycle.
                                   cycle(s).
8. Temperature of the carbon bed  Maximum             Continuously        Every 15 minutes    Average of
 after regeneration [and within    temperature of      during              during              regeneration
 15 minutes of completing any      the carbon bed      regeneration and    regeneration        cycle.
 cooling cycle(s)].                after               for 15 minutes      cycle (including
                                   regeneration.       after completing    any cooling
                                                       any cooling         cycle).
                                                       cycle(s).
9. Breakthrough.................  As defined in Sec.  As required by      Each monitoring     N/A
                                     60.611a.          Sec.                event.
                                                       60.613a(a)(6)(iii
                                                       )(B).
----------------------------------------------------------------------------------------------------------------
                                                   Condensers
----------------------------------------------------------------------------------------------------------------
10. Exit (product side)           Maximum             Continuous........  Every 15 minutes..  3-hour block
 temperature.                      temperature.                                                average.
----------------------------------------------------------------------------------------------------------------
                                     Scrubbers for halogenated vent streams
----------------------------------------------------------------------------------------------------------------
11. pH of scrubber effluent.....  Minimum pH........  Continuous........  Every 15 minutes..  3-hour block
                                                                                               average.
12. Influent liquid flow........  Minimum inlet       Continuous........  Every 15 minutes..  3-hour block
                                   liquid flow.                                                average.
13. Influent liquid flow rate     Minimum influent    Continuous........  Every 15 minutes..  3-hour block
 and gas stream flow rate.         liquid-to-gas                                               average.
                                   ratio.
----------------------------------------------------------------------------------------------------------------
                                              Thermal incinerators
----------------------------------------------------------------------------------------------------------------
14. Firebox temperature.........  Minimum firebox     Continuous........  Every 15 minutes..  3-hour block
                                   temperature.                                                average.
----------------------------------------------------------------------------------------------------------------
 Control devices other than an incinerator, boiler, process heater, or flare; or recovery devices other than an
                                     absorber, condenser, or carbon adsorber
----------------------------------------------------------------------------------------------------------------
15. As specified by the           As specified by     As specified by     As specified by     As specified by
 Administrator.                    the Administrator.  the Administrator.  the Administrator.  the
                                                                                               Administrator.
----------------------------------------------------------------------------------------------------------------


[[Page 43105]]


   Table 4 to Subpart IIIa of Part 60--Calibration and Quality Control
     Requirements for Continuous Parameter Monitoring System (CPMS)
------------------------------------------------------------------------
                                                            And your
 If you monitor this parameter. .     Your accuracy       calibration
                .                   requirements are.  requirements are.
                                           . .                . .
------------------------------------------------------------------------
1. Temperature...................  a. 1    c. Performance
                                    percent over the    evaluation
                                    normal range of     annually and
                                    temperature         following any
                                    measured or 2.8     period of more
                                    degrees Celsius     than 24 hours
                                    (5 degrees          throughout which
                                    Fahrenheit),        the temperature
                                    whichever is        exceeded the
                                    greater, for non-   maximum rated
                                    cryogenic           temperature of
                                    temperature         the sensor, or
                                    ranges.             the data
                                   b. 2.5   recorder was off
                                    percent over the    scale.
                                    normal range of    d. Visual
                                    temperature         inspections and
                                    measured or 2.8     checks of CPMS
                                    degrees Celsius     operation every
                                    (5 degrees          3 months, unless
                                    Fahrenheit),        the CPMS has a
                                    whichever is        redundant
                                    greater, for        temperature
                                    cryogenic           sensor.
                                    temperature        e. Selection of a
                                    ranges.             representative
                                                        measurement
                                                        location.
2. Flow Rate.....................  a. 5    d. Performance
                                    percent over the    evaluation
                                    normal range of     annually and
                                    flow measured or    following any
                                    1.9 liters per      period of more
                                    minute (0.5         than 24 hours
                                    gallons per         throughout which
                                    minute),            the flow rate
                                    whichever is        exceeded the
                                    greater, for        maximum rated
                                    liquid flow rate.   flow rate of the
                                   b. 5     sensor, or the
                                    percent over the    data recorder
                                    normal range of     was off scale.
                                    flow measured or   e. Checks of all
                                    280 liters per      mechanical
                                    minute (10 cubic    connections for
                                    feet per minute),   leakage monthly.
                                    whichever is       f. Visual
                                    greater, for gas    inspections and
                                    flow rate.          checks of CPMS
                                   c. 5     operation every
                                    percent over the    3 months, unless
                                    normal range        the CPMS has a
                                    measured for mass   redundant flow
                                    flow rate.          sensor.
                                                       g. Selection of a
                                                        representative
                                                        measurement
                                                        location where
                                                        swirling flow or
                                                        abnormal
                                                        velocity
                                                        distributions
                                                        due to upstream
                                                        and downstream
                                                        disturbances at
                                                        the point of
                                                        measurement are
                                                        minimized.
3. pH............................  a. 0.2  b. Performance
                                    pH units.           evaluation
                                                        annually.
                                                        Conduct a two-
                                                        point
                                                        calibration with
                                                        one of the two
                                                        buffer solutions
                                                        having a pH
                                                        within 1 of the
                                                        pH of the
                                                        operating limit.
                                                       c. Visual
                                                        inspections and
                                                        checks of CPMS
                                                        operation every
                                                        3 months, unless
                                                        the CPMS has a
                                                        redundant pH
                                                        sensor.
                                                       d. Select a
                                                        measurement
                                                        location that
                                                        provides a
                                                        representative
                                                        sample of
                                                        scrubber
                                                        effluent and
                                                        that ensures the
                                                        fluid is
                                                        properly mixed.
4. Specific Gravity..............  a. 0.02          evaluation
                                    specific gravity    annually.
                                    units.             c. Visual
                                                        inspections and
                                                        checks of CPMS
                                                        operation every
                                                        3 months, unless
                                                        the CPMS has a
                                                        redundant
                                                        specific gravity
                                                        sensor.
                                                       d. Select a
                                                        measurement
                                                        location that
                                                        provides a
                                                        representative
                                                        sample of
                                                        specific gravity
                                                        of the absorbing
                                                        liquid effluent
                                                        and that ensures
                                                        the fluid is
                                                        properly mixed.
------------------------------------------------------------------------


0
26. Revise the heading of subpart NNN to read as follows:

Subpart NNN--Standards of Performance for Volatile Organic Compound 
(VOC) Emissions From Synthetic Organic Chemical Manufacturing 
Industry (SOCMI) Distillation Operations After December 30, 1983, 
and on or Before April 25, 2023

0
27. Amend Sec.  60.660 by revising paragraphs (b) introductory text and 
(c)(6) and adding paragraph (e) to read as follows:


Sec.  60.660  Applicability and designation of affected facility.

* * * * *
    (b) The affected facility is any of the following for which 
construction, modification, or reconstruction commenced after December 
30, 1983, and on or before April 25, 2023:
* * * * *
    (c) * * *
    (6) Each affected facility operated with a vent stream flow rate 
less than 0.008 scm/min is exempt from all provisions of this subpart 
except for the test method and procedure and the recordkeeping and 
reporting requirements in Sec. Sec.  60.664(h) and 60.665(i), (l)(5), 
and (o).
* * * * *
    (e) Owners and operators of flares that are subject to the flare 
related requirements of this subpart and flare related requirements of 
any other regulation in this part or 40 CFR part 61 or 63, may elect to 
comply with the requirements in Sec.  60.669a in lieu of all flare 
related requirements in any other regulation in this part or 40 CFR 
part 61 or 63.

0
28. Amend Sec.  60.661 by revising the definition of ``Flame zone'' to 
read as follows:


Sec.  60.661  Definitions.

* * * * *
    Flame zone means the portion of the combustion chamber in a boiler 
or process heater occupied by the flame envelope.
* * * * *

0
29. Amend Sec.  60.664 by revising paragraphs (b)(4) introductory text 
and (e) to read as follows:


Sec.  60.664  Test methods and procedures.

* * * * *
    (b) * * *
    (4) Method 18 of appendix A-6 to this part to determine the 
concentration of TOC in the control device outlet and the concentration 
of TOC in the inlet when the reduction efficiency of the control device 
is to be determined. ASTM D6420-18 (incorporated by reference, see 
Sec.  [thinsp]60.17) may be used in lieu of Method 18, if the target 
compounds are all known and are all listed in Section 1.1 of ASTM 
D6420-18 as measurable; ASTM D6420-18 may not be used for methane and 
ethane; and ASTM D6420-18 may not be used as a total VOC method.
* * * * *
    (e) The following test methods, except as provided under Sec.  
60.8(b), shall be used for determining the net heating value of the gas 
combusted to determine compliance under Sec.  60.662(b) and for 
determining the process vent stream TRE index value to determine 
compliance under Sec.  60.662(c).
    (1)(i) Method 1 or 1A of appendix A-1 to this part, as appropriate, 
for selection of the sampling site. The sampling site for the vent 
stream flow rate and molar composition determination prescribed in 
paragraphs (e)(2) and (3) of this section shall be, except for the 
situations outlined in paragraph (e)(1)(ii) of this section, prior to 
the inlet of any control device, prior to any post-distillation 
dilution of the stream with air, and prior to any post-distillation 
introduction of halogenated compounds into the process vent stream. No 
transverse site selection method is needed for vents smaller than 10 
centimeters (4 inches) in diameter.
    (ii) If any gas stream other than the distillation vent stream from 
the affected facility is normally conducted through the final recovery 
device.

[[Page 43106]]

    (A) The sampling site for vent stream flow rate and molar 
composition shall be prior to the final recovery device and prior to 
the point at which the nondistillation stream is introduced.
    (B) The efficiency of the final recovery device is determined by 
measuring the TOC concentration using Method 18 of appendix A-6 to this 
part, or ASTM D6420-18 (incorporated by reference, see Sec.  
[thinsp]60.17) as specified in paragraph (b)(4) of this section, at the 
inlet to the final recovery device after the introduction of any 
nondistillation vent stream and at the outlet of the final recovery 
device.
    (C) This efficiency is applied to the TOC concentration measured 
prior to the final recovery device and prior to the introduction of the 
nondistillation stream to determine the concentration of TOC in the 
distillation vent stream from the final recovery device. This 
concentration of TOC is then used to perform the calculations outlined 
in Sec.  60.664(e)(4) and (5).
    (2) The molar composition of the process vent stream shall be 
determined as follows:
    (i) Method 18 of appendix A-6 to this part, or ASTM D6420-18 
(incorporated by reference, see Sec.  [thinsp]60.17) as specified in 
paragraph (b)(4) of this section, to measure the concentration of TOC 
including those containing halogens.
    (ii) ASTM D1946-77 or 90 (Reapproved 1994) (incorporation by 
reference as specified in Sec.  60.17 of this part) to measure the 
concentration of carbon monoxide and hydrogen.
    (iii) Method 4 of appendix A-3 to this part to measure the content 
of water vapor.
    (3) The volumetric flow rate shall be determined using Method 2, 
2A, 2C, or 2D of appendix A-1 to this part, as appropriate.
    (4)(i) The net heating value of the vent stream shall be calculated 
using the following equation:
[GRAPHIC] [TIFF OMITTED] TR16MY24.035

Where:

HT = Net heating value of the sample, MJ/scm (Btu/scf), 
where the net enthalpy per mole of vent stream is based on 
combustion at 25 [deg]C and 760 mm Hg (77 [deg]F and 30 in. Hg), but 
the standard temperature for determining the volume corresponding to 
one mole is 20 [deg]C (68 [deg]F).
K1 = 1.74 x 10-7 (1/ppm) (g-mole/scm) (MJ/
kcal) (metric units), where standard temperature for (g-mole/scm) is 
20 [deg]C.
= 1.03 x 10-11 (1/ppm) (lb-mole/scf) (Btu/kcal) (English 
units) where standard temperature for (lb/mole/scf) is 68 [deg]F.
Cj = Concentration on a wet basis of compound j in ppm, 
as measured for organics by Method 18 of appendix A-6 to this part, 
or ASTM D6420-18 (incorporated by reference, see Sec.  
[thinsp]60.17) as specified in paragraph (b)(4) of this section, and 
measured for hydrogen and carbon monoxide by ASTM D1946-77 or 90 
(Reapproved 1994) (incorporated by reference, see Sec.  60.17) as 
indicated in paragraph (e)(2) of this section.
Hj = Net heat of combustion of compound j, kcal/(g-mole) 
[kcal/(lb-mole)], based on combustion at 25 [deg]C and 760 mm Hg (77 
[deg]F and 30 in. Hg).

    (ii) The heats of combustion of vent stream components would be 
required to be determined using ASTM D2382-76 (incorporated by 
reference as specified in Sec.  60.17) if published values are not 
available or cannot be calculated.
    (5) The emission rate of TOC in the vent stream shall be calculated 
using the following equation:
[GRAPHIC] [TIFF OMITTED] TR16MY24.036

Where:

ETOC = Measured emission rate of TOC, kg/hr (lb/hr).
K2 = 2.494 x 10-6 (1/ppm) (g-mole/scm) (kg/g) 
(min/hr) (metric units), where standard temperature for (g-mole/scm) 
is 20 [deg]C.
= 1.557 x 10-7 (1/ppm) (lb-mole/scf) (min/hr) (English 
units), where standard temperature for (lb-mole/scf) is 68 [deg]F.
Cj = Concentration on a wet basis of compound j in ppm, 
as measured by Method 18 of appendix A-6 to this part, or ASTM 
D6420-18 (incorporated by reference, see Sec.  [thinsp]60.17) as 
specified in paragraph (b)(4) of this section, as indicated in 
paragraph (e)(2) of this section.
Mj = Molecular weight of sample j, g/g-mole (lb/lb-mole).
Qs = Vent stream flow rate, scm/min (scf/min), at a 
temperature of 20 [deg]C (68 [deg]F).

    (6) The total process vent stream concentration (by volume) of 
compounds containing halogens (ppmv, by compound) shall be summed from 
the individual concentrations of compounds containing halogens which 
were measured by Method 18 of appendix A-6 to this part, or ASTM D6420-
18 (incorporated by reference, see Sec.  [thinsp]60.17) as specified in 
paragraph (b)(4) of this section.
* * * * *

0
30. Amend Sec.  60.665 by revising paragraphs (b) introductory text, 
(l) introductory text, (l)(5) and (6), and (m) and adding paragraphs 
(q), (r), and (s) as follows:


Sec.  60.665  Reporting and recordkeeping requirements.

* * * * *
    (b) Each owner or operator subject to the provisions of this 
subpart shall keep an up-to-date, readily accessible record of the 
following data measured during each performance test, and also include 
the following data in the report of the initial performance test 
required under Sec.  60.8. Where a boiler or process heater with a 
design heat input capacity of 44 MW (150 million Btu/hour) or greater 
is used to comply with Sec.  60.662(a), a report containing performance 
test data need not be submitted, but a report containing the 
information in Sec.  60.665(b)(2)(i) is required. The same data 
specified in this section shall be submitted in the reports of all 
subsequently required performance tests where either the emission 
control efficiency of a control device, outlet concentration of TOC, or 
the TRE index value of a vent stream from a recovery system is 
determined. Beginning on July 15, 2024, owners and operators must 
submit the performance test report following the procedures specified 
in paragraph (q) of this section. Data collected using test methods 
that are

[[Page 43107]]

supported by the EPA's Electronic Reporting Tool (ERT) as listed on the 
EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test must 
be submitted in a file format generated using the EPA's ERT. 
Alternatively, the owner or operator may submit an electronic file 
consistent with the extensible markup language (XML) schema listed on 
the EPA's ERT website. Data collected using test methods that are not 
supported by the EPA's ERT as listed on the EPA's ERT website at the 
time of the test must be included as an attachment in the ERT or an 
alternate electronic file.
* * * * *
    (l) Each owner or operator that seeks to comply with the 
requirements of this subpart by complying with the requirements of 
Sec.  60.660 (c)(4), (c)(5), or (c)(6) or Sec.  60.662 shall submit to 
the Administrator semiannual reports of the following recorded 
information. The initial report shall be submitted within 6 months 
after the initial start-up date. On and after July 15, 2025 or once the 
report template for this subpart has been available on the Compliance 
and Emissions Data Reporting Interface (CEDRI) website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 year, 
whichever date is later, owners and operators must submit all 
subsequent reports using the appropriate electronic report template on 
the CEDRI website for this subpart and following the procedure 
specified in paragraph (q) of this section. The date report templates 
become available will be listed on the CEDRI website. Unless the 
Administrator or delegated state agency or other authority has approved 
a different schedule for submission of reports, the report must be 
submitted by the deadline specified in this subpart, regardless of the 
method in which the report is submitted.
* * * * *
    (5) Any change in equipment or process operation that increases the 
operating vent stream flow rate above the low flow exemption level in 
Sec.  60.660(c)(6), including a measurement of the new vent stream flow 
rate, as recorded under Sec.  60.665(i). These must be reported as soon 
as possible after the change and no later than 180 days after the 
change. These reports may be submitted either in conjunction with 
semiannual reports or as a single separate report. A performance test 
must be completed with the same time period to verify the recalculated 
flow value and to obtain the vent stream characteristics of heating 
value and ETOC. The performance test is subject to the 
requirements of Sec.  60.8, and the performance test must be reported 
according to paragraph (b) of this section. Unless the facility 
qualifies for an exemption under the low capacity exemption status in 
Sec.  60.660(c)(5), the facility must begin compliance with the 
requirements set forth in Sec.  60.662.
    (6) Any change in equipment or process operation, as recorded under 
paragraph (j) of this section, that increases the design production 
capacity above the low capacity exemption level in Sec.  60.660(c)(5) 
and the new capacity resulting from the change for the distillation 
process unit containing the affected facility. These must be reported 
as soon as possible after the change and no later than 180 days after 
the change. These reports may be submitted either in conjunction with 
semiannual reports or as a single separate report. A performance test 
must be completed within the same time period to obtain the vent stream 
flow rate, heating value, and ETOC. The performance test is 
subject to the requirements of Sec.  60.8, and the performance test 
must be reported according to paragraph (b) of this section. The 
facility must begin compliance with the requirements set forth in Sec.  
60.660(d) or Sec.  60.662. If the facility chooses to comply with Sec.  
60.662, the facility may qualify for an exemption in Sec.  60.660(c)(4) 
or (6).
* * * * *
    (m) The requirements of Sec.  60.665(l) remain in force until and 
unless EPA, in delegating enforcement authority to a State under 
section 111(c) of the Act, approves reporting requirements or an 
alternative means of compliance surveillance adopted by such State. In 
that event, affected sources within the State will be relieved of the 
obligation to comply with Sec.  60.665(l), provided that they comply 
with the requirements established by the State. The EPA will not 
approve a waiver of electronic reporting to the EPA in delegating 
enforcement authority. Thus, electronic reporting to the EPA cannot be 
waived, and as such, the provisions of this paragraph cannot be used to 
relieve owners or operators of affected facilities of the requirement 
to submit the electronic reports required in this section to the EPA.
* * * * *
    (q) If an owner or operator is required to submit notifications or 
reports following the procedure specified in this paragraph (q), the 
owner or operator must submit notifications or reports to the EPA via 
CEDRI, which can be accessed through the EPA's Central Data Exchange 
(CDX) (https://cdx.epa.gov/). The EPA will make all the information 
submitted through CEDRI available to the public without further notice 
to the owner or operator. Do not use CEDRI to submit information the 
owner or operator claims as CBI. Although the EPA does not expect 
persons to assert a claim of CBI, if an owner or operator wishes to 
assert a CBI claim for some of the information in the report or 
notification, the owner or operator must submit a complete file in the 
format specified in this subpart, including information claimed to be 
CBI, to the EPA following the procedures in paragraphs (q)(1) and (2) 
of this section. Clearly mark the part or all of the information that 
claimed to be CBI. Information not marked as CBI may be authorized for 
public release without prior notice. Information marked as CBI will not 
be disclosed except in accordance with procedures set forth in 40 CFR 
part 2. All CBI claims must be asserted at the time of submission. 
Anything submitted using CEDRI cannot later be claimed CBI. 
Furthermore, under CAA section 114(c), emissions data is not entitled 
to confidential treatment, and the EPA is required to make emissions 
data available to the public. Thus, emissions data will not be 
protected as CBI and will be made publicly available. The owner or 
operator must submit the same file submitted to the CBI office with the 
CBI omitted to the EPA via the EPA's CDX as described earlier in this 
paragraph (q).
    (1) The preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
[email protected], and as described above, should include clear CBI 
markings. ERT files should be flagged to the attention of the Group 
Leader, Measurement Policy Group; all other files should be flagged to 
the attention of the SOCMI NSPS Sector Lead. Owners and operators who 
do not have their own file sharing service and who require assistance 
with submitting large electronic files that exceed the file size limit 
for email attachments should email [email protected] to request a file 
transfer link.
    (2) If an owner or operator cannot transmit the file 
electronically, the owner or operator may send CBI information through 
the postal service to the following address: OAQPS Document Control 
Officer (C404-02), OAQPS, U.S. Environmental Protection Agency, 109 
T.W. Alexander Drive, P.O. Box 12055, Research Triangle Park,

[[Page 43108]]

North Carolina 27711. ERT files should be sent to the attention of the 
Group Leader, Measurement Policy Group, and all other files should be 
sent to the attention of the SOCMI NSPS Sector Lead. The mailed CBI 
material should be double wrapped and clearly marked. Any CBI markings 
should not show through the outer envelope.
    (r) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX may assert a 
claim of EPA system outage for failure to timely comply with the 
electronic submittal requirement. To assert a claim of EPA system 
outage, owners and operators must meet the requirements outlined in 
paragraphs (r)(1) through (7) of this section.
    (1) The owner or operator must have been or will be precluded from 
accessing CEDRI and submitting a required report within the time 
prescribed due to an outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (5) The owner or operator must provide to the Administrator a 
written description identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which the owner or operator proposes to report, or 
if the owner or operator has already met the reporting requirement at 
the time of the notification, the date the report was submitted.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (s) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX may assert a 
claim of force majeure for failure to timely comply with the electronic 
submittal requirement. To assert a claim of force majeure, owners and 
operators must meet the requirements outlined in paragraphs (s)(1) 
through (5) of this section.
    (1) An owner or operator may submit a claim if a force majeure 
event is about to occur, occurs, or has occurred or there are lingering 
effects from such an event within the period of time beginning five 
business days prior to the date the submission is due. For the purposes 
of this section, a force majeure event is defined as an event that will 
be or has been caused by circumstances beyond the control of the 
affected facility, its contractors, or any entity controlled by the 
affected facility that prevents the owner or operator from complying 
with the requirement to submit a report electronically within the time 
period prescribed. Examples of such events are acts of nature (e.g., 
hurricanes, earthquakes, or floods), acts of war or terrorism, or 
equipment failure or safety hazard beyond the control of the affected 
facility (e.g., large scale power outage).
    (2) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (3) An owner or operator must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which the owner or operator proposes to report, or 
if the owner or operator has already met the reporting requirement at 
the time of the notification, the date the report was submitted.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.

0
31. Amend Sec.  60.668 by revising paragraph (b) to read as follows:


Sec.  60.668  Delegation of authority.

* * * * *
    (b) Authorities which will not be delegated to States: Sec.  
60.663(e) and approval of an alternative to any electronic reporting to 
the EPA required by this subpart.

0
32. Add subpart NNNa to read as follows:

Subpart NNNa--Standards of Performance for Volatile Organic 
Compound (VOC) Emissions From Synthetic Organic Chemical 
Manufacturing Industry (SOCMI) Distillation Operations for Which 
Construction, Reconstruction, or Modification Commenced After April 
25, 2023

Sec.
60.660a Am I subject to this subpart?
60.661a What definitions must I know?
60.662a What standards and associated requirements must I meet?
60.663a What are my monitoring, installation, operation, and 
maintenance requirements?
60.664a What test methods and procedures must I use to determine 
compliance with the standards?
60.665a What records must I keep and what reports must I submit?
60.666a What do the terms associated with reconstruction mean for 
this subpart?
60.667a What are the chemicals that I must produce to be affected by 
subpart NNNa?
60.668a [Reserved]
60.669a What are my requirements if I use a flare to comply with 
this subpart?
60.670a What are my requirements for closed vent systems?
Table 1 to Subpart NNNa of Part 60--Emission Limits and Standards 
for Vent Streams
Table 2 to Subpart NNNa of Part 60--Monitoring Requirements for 
Complying With 98 Weight-Percent Reduction of Total Organic 
Compounds Emissions or a Limit of 20 Parts Per Million by Volume
Table 3 to Subpart NNNa of Part 60--Operating Parameters, Operating 
Parameter Limits and Data Monitoring, Recordkeeping and Compliance 
Frequencies
Table 4 to Subpart NNNa of Part 60--Calibration and Quality Control 
Requirements for Continuous Parameter Monitoring System (CPMS)

Subpart NNNa--Standards of Performance for Volatile Organic 
Compound (VOC) Emissions From Synthetic Organic Chemical 
Manufacturing Industry (SOCMI) Distillation Operations for Which 
Construction, Reconstruction, or Modification Commenced After April 
25, 2023


Sec.  60.660a  Am I subject to this subpart?

    (a) You are subject to this subpart if you operate an affected 
facility designated in paragraph (b) of this section that produces any 
of the chemicals listed in Sec.  60.667a as a product, co-product, by-
product, or

[[Page 43109]]

intermediate, except as provided in paragraph (c) of this section.
    (b) The affected facility is any of the following for which 
construction, modification, or reconstruction commenced after April 25, 
2023:
    (1) Each distillation unit not discharging its vent stream into a 
recovery system.
    (2) Each combination of a distillation unit and the recovery system 
into which its vent stream is discharged.
    (3) Each combination of two or more distillation units and the 
common recovery system into which their vent streams are discharged.
    (c) Exemptions from the provisions of paragraph (a) of this section 
are as follows:
    (1) Any distillation unit operating as part of a process unit which 
produces coal tar or beverage alcohols, or which uses, contains, and 
produces no VOC is not an affected facility.
    (2) Any distillation unit that is subject to the provisions of 
subpart DDD is not an affected facility.
    (3) Any distillation unit that is designed and operated as a batch 
operation is not an affected facility.
    (4) Each affected facility in a process unit with a total design 
capacity for all chemicals produced within that unit of less than one 
gigagram per year is exempt from all provisions of this subpart except 
for the recordkeeping and reporting requirements in Sec.  60.665a(h), 
(j)(6), and (o).
    (5) Each affected facility operated with a vent stream flow rate 
less than 0.008 standard cubic meter per minute (scm/min) is exempt 
from all provisions of this subpart except for the test method and 
procedure and the recordkeeping and reporting requirements in Sec.  
60.664a(e) and Sec.  60.665a(i), (j)(7), and (p).
    (6) Each affected facility operated with a vent stream flow rate 
less than 0.001 pound per hour (lb/hr) of TOC is exempt from all 
provisions of this subpart except for the test method and procedure and 
the recordkeeping and reporting requirements in Sec. Sec.  60.664a(f) 
and 60.665a(i), (j)(7), and (p).
    (7) A vent stream going to a fuel gas system as defined in Sec.  
63.661a.


Sec.  60.661a  What definitions must I know?

    As used in this subpart, all terms not defined herein have the 
meaning given them in the Clean Air Act and subpart A of this part.
    Batch distillation operation means a noncontinuous distillation 
operation in which a discrete quantity or batch of liquid feed is 
charged into a distillation unit and distilled at one time. After the 
initial charging of the liquid feed, no additional liquid is added 
during the distillation operation.
    Breakthrough means the time when the level of TOC, measured at the 
outlet of the first bed, has been detected is at the highest 
concentration allowed to be discharged from the adsorber system and 
indicates that the adsorber bed should be replaced.
    Boiler means any enclosed combustion device that extracts useful 
energy in the form of steam.
    By compound means by individual stream components, not carbon 
equivalents.
    Closed vent system means a system that is not open to the 
atmosphere and is composed of piping, ductwork, connections, and, if 
necessary, flow inducing devices that transport gas or vapor from an 
emission point to a control device.
    Continuous recorder means a data recording device recording an 
instantaneous data value at least once every 15 minutes.
    Distillation operation means an operation separating one or more 
feed stream(s) into two or more exit stream(s), each exit stream having 
component concentrations different from those in the feed stream(s). 
The separation is achieved by the redistribution of the components 
between the liquid and vapor-phase as they approach equilibrium within 
the distillation unit.
    Distillation unit means a device or vessel in which distillation 
operations occur, including all associated internals (such as trays or 
packing) and accessories (such as reboiler, condenser, vacuum pump, 
steam jet, etc.), plus any associated recovery system.
    Flame zone means the portion of the combustion chamber in a boiler 
or process heater occupied by the flame envelope.
    Flow indicator means a device which indicates whether gas flow is 
present in a vent stream.
    Fuel gas means gases that are combusted to derive useful work or 
heat.
    Fuel gas system means the offsite and onsite piping and flow and 
pressure control system that gathers gaseous stream(s) generated by 
onsite operations, may blend them with other sources of gas, and 
transports the gaseous stream for use as fuel gas in combustion devices 
or in in-process combustion equipment such as furnaces and gas turbines 
either singly or in combination.
    Halogenated vent stream means any vent stream determined to have a 
total concentration (by volume) of compounds containing halogens of 20 
ppmv (by compound) or greater.
    Incinerator means any enclosed combustion device that is used for 
destroying organic compounds and does not extract energy in the form of 
steam or process heat.
    Pressure-assisted multi-point flare means a flare system consisting 
of multiple flare burners in staged arrays whereby the vent stream 
pressure is used to promote mixing and smokeless operation at the flare 
burner tips. Pressure-assisted multi-point flares are designed for 
smokeless operation at velocities up to Mach = 1 conditions (i.e., 
sonic conditions), can be elevated or at ground level, and typically 
use cross-lighting for flame propagation to combust any flare vent 
gases sent to a particular stage of flare burners.
    Primary fuel means the fuel fired through a burner or a number of 
similar burners. The primary fuel provides the principal heat input to 
the device, and the amount of fuel is sufficient to sustain operation 
without the addition of other fuels.
    Process heater means a device that transfers heat liberated by 
burning fuel to fluids contained in tubes, including all fluids except 
water that is heated to produce steam.
    Process unit means equipment assembled and connected by pipes or 
ducts to produce, as intermediates or final products, one or more of 
the chemicals in Sec.  60.667a. A process unit can operate 
independently if supplied with sufficient fuel or raw materials and 
sufficient product storage facilities.
    Product means any compound or chemical listed in Sec.  60.667a that 
is produced for sale as a final product as that chemical, or for use in 
the production of other chemicals or compounds. By-products, co-
products, and intermediates are considered to be products.
    Recovery device means an individual unit of equipment, such as an 
absorber, carbon adsorber, or condenser, capable of and used for the 
purpose of recovering chemicals for use, reuse, or sale.
    Recovery system means an individual recovery device or series of 
such devices applied to the same vent stream.
    Relief valve means a valve used only to release an unplanned, 
nonroutine discharge. A relief valve discharge results from an operator 
error, a malfunction such as a power failure or equipment failure, or 
other unexpected cause that requires immediate venting of gas from 
process equipment in order to avoid safety hazards or equipment damage.

[[Page 43110]]

    Total organic compounds (TOC) means those compounds measured 
according to the procedures in Method 18 of appendix A-6 of this part 
or the concentration of organic compounds measured according to the 
procedures in Method 21 or Method 25A of appendix A-7 of this part.
    Vent stream means any gas stream discharged directly from a 
distillation facility to the atmosphere or indirectly to the atmosphere 
after diversion through other process equipment. The vent stream 
excludes equipment leaks including, but not limited to, pumps, 
compressors, and valves.


Sec.  60.662a  What standards and associated requirements must I meet?

    (a) You must comply with the emission limits and standards 
specified in table 1 to this subpart and the requirements specified in 
paragraphs (b) and (c) of this section for each vent stream on and 
after the date on which the initial performance test required by 
Sec. Sec.  60.8 and 60.664a is completed, but not later than 60 days 
after achieving the maximum production rate at which the affected 
facility will be operated, or 180 days after the initial start-up, 
whichever date comes first. The standards in this section apply at all 
times, including periods of startup, shutdown and malfunction. As 
provided in Sec.  60.11(f), this provision supersedes the exemptions 
for periods of startup, shutdown and malfunction in the general 
provisions in subpart A of this part.
    (b) The following release events from an affected facility are a 
violation of the emission limits and standards specified in table 1 to 
this subpart.
    (1) Any relief valve discharge to the atmosphere of a vent stream.
    (2) The use of a bypass line at any time on a closed vent system to 
divert emissions to the atmosphere, or to a control device or recovery 
device not meeting the requirements specified in Sec.  60.663a.
    (c) You may designate a vent stream as a maintenance vent if the 
vent is only used as a result of startup, shutdown, maintenance, or 
inspection of equipment where equipment is emptied, depressurized, 
degassed, or placed into service. You must comply with the applicable 
requirements in paragraphs (c)(1) through (3) of this section for each 
maintenance vent. Any vent stream designated as a maintenance vent is 
only subject to the maintenance vent provisions in this paragraph (c) 
and the associated recordkeeping and reporting requirements in Sec.  
60.665a(g), respectively.
    (1) Prior to venting to the atmosphere, remove process liquids from 
the equipment as much as practical and depressurize the equipment to 
either: A flare meeting the requirements of Sec.  60.669a, as 
applicable, or using any combination of a non-flare control device or 
recovery device meeting the requirements in table 1 to this subpart 
until one of the following conditions, as applicable, is met.
    (i) The vapor in the equipment served by the maintenance vent has a 
lower explosive limit (LEL) of less than 10 percent.
    (ii) If there is no ability to measure the LEL of the vapor in the 
equipment based on the design of the equipment, the pressure in the 
equipment served by the maintenance vent is reduced to 5 pounds per 
square inch gauge (psig) or less. Upon opening the maintenance vent, 
active purging of the equipment cannot be used until the LEL of the 
vapors in the maintenance vent (or inside the equipment if the 
maintenance vent is a hatch or similar type of opening) is less than 10 
percent.
    (iii) The equipment served by the maintenance vent contains less 
than 50 pounds of total VOC.
    (iv) If, after applying best practices to isolate and purge 
equipment served by a maintenance vent, none of the applicable 
criterion in paragraphs (c)(1)(i) through (iii) of this section can be 
met prior to installing or removing a blind flange or similar equipment 
blind, then the pressure in the equipment served by the maintenance 
vent must be reduced to 2 psig or less before installing or removing 
the equipment blind. During installation or removal of the equipment 
blind, active purging of the equipment may be used provided the 
equipment pressure at the location where purge gas is introduced 
remains at 2 psig or less.
    (2) Except for maintenance vents complying with the alternative in 
paragraph (c)(1)(iii) of this section, you must determine the LEL or, 
if applicable, equipment pressure using process instrumentation or 
portable measurement devices and follow procedures for calibration and 
maintenance according to manufacturer's specifications.
    (3) For maintenance vents complying with the alternative in 
paragraph (c)(1)(iii) of this section, you must determine mass of VOC 
in the equipment served by the maintenance vent based on the equipment 
size and contents after considering any contents drained or purged from 
the equipment. Equipment size may be determined from equipment design 
specifications. Equipment contents may be determined using process 
knowledge.


Sec.  60.663a  What are my monitoring, installation, operation, and 
maintenance requirements?

    (a) Except as specified in paragraphs (a)(5) through (7) of this 
section, if you use a non-flare control device or recovery system to 
comply with the TOC emission limit specified in table 1 to this 
subpart, then you must comply with paragraphs (a)(1) through (4), (b), 
and (c) of this section.
    (1) Install a continuous parameter monitoring system(s) (CPMS) and 
monitor the operating parameter(s) applicable to the control device or 
recovery system as specified in table 2 to this subpart or established 
according to paragraph (c) of this section.
    (2) Establish the applicable minimum, maximum, or range for the 
operating parameter limit as specified in table 3 to this subpart or 
established according to paragraph (c) of this section by calculating 
the value(s) as the arithmetic average of operating parameter 
measurements recorded during the three test runs conducted for the most 
recent performance test. You may operate outside of the established 
operating parameter limit(s) during subsequent performance tests in 
order to establish new operating limits. You must include the updated 
operating limits with the performance test results submitted to the 
Administrator pursuant to Sec.  60.665a(b). Upon establishment of a new 
operating limit, you must thereafter operate under the new operating 
limit. If the Administrator determines that you did not conduct the 
performance test in accordance with the applicable requirements or that 
the operating limit established during the performance test does not 
correspond to the conditions specified in Sec.  60.664a(a), then you 
must conduct a new performance test and establish a new operating 
limit.
    (3) Monitor, record, and demonstrate continuous compliance using 
the minimum frequencies specified in table 3 to this subpart or 
established according to paragraph (c) of this section.
    (4) Comply with the calibration and quality control requirements as 
specified in table 4 to this subpart or established according to 
paragraph (c) of this section that are applicable to the CPMS used.
    (5) Any vent stream introduced with primary fuel into a boiler or 
process heater is exempt from the requirements specified in paragraphs 
(a)(1) through (4) of this section.
    (6) If you vent emissions through a closed vent system to an 
adsorber(s) that

[[Page 43111]]

cannot be regenerated or a regenerative adsorber(s) that is regenerated 
offsite, then you must install a system of two or more adsorber units 
in series and comply with the requirements specified in paragraphs 
(a)(6)(i) through (iii) of this section in addition to the requirements 
specified in paragraphs (a)(1) through (4) of this section.
    (i) Conduct an initial performance test or design evaluation of the 
adsorber and establish the breakthrough limit and adsorber bed life.
    (ii) Monitor the TOC concentration through a sample port at the 
outlet of the first adsorber bed in series according to the schedule in 
paragraph (a)(6)(iii)(B) of this section. You must measure the 
concentration of TOC using either a portable analyzer, in accordance 
with Method 21 of appendix A-7 of this part using methane, propane, or 
isobutylene as the calibration gas or Method 25A of appendix A-7 of 
this part using methane or propane as the calibration gas.
    (iii) Comply with paragraph (a)(6)(iii)(A) of this section and 
comply with the monitoring frequency according to paragraph 
(a)(6)(iii)(B) of this section.
    (A) The first adsorber in series must be replaced immediately when 
breakthrough, as defined in Sec.  60.661a, is detected between the 
first and second adsorber. The original second adsorber (or a fresh 
canister) will become the new first adsorber and a fresh adsorber will 
become the second adsorber. For purposes of this paragraph 
(a)(6)(iii)(A), ``immediately'' means within 8 hours of the detection 
of a breakthrough for adsorbers of 55 gallons or less, and within 24 
hours of the detection of a breakthrough for adsorbers greater than 55 
gallons. You must monitor at the outlet of the first adsorber within 3 
days of replacement to confirm it is performing properly.
    (B) Based on the adsorber bed life established according to 
paragraph (a)(6)(i) of this section and the date the adsorbent was last 
replaced, conduct monitoring to detect breakthrough at least monthly if 
the adsorbent has more than 2 months of life remaining, at least weekly 
if the adsorbent has between 2 months and 2 weeks of life remaining, 
and at least daily if the adsorbent has 2 weeks or less of life 
remaining.
    (7) If you install a continuous emissions monitoring system (CEMS) 
to demonstrate compliance with the TOC standard in table 1 of this 
subpart, you must comply with the requirements specified in Sec.  
60.664a(g) in lieu of the requirements specified in paragraphs (a)(1) 
through (4) and (c) of this section.
    (b) If you vent emissions through a closed vent system to a boiler 
or process heater, then the vent stream must be introduced into the 
flame zone of the boiler or process heater.
    (c) If you seek to demonstrate compliance with the standards 
specified under Sec.  60.662a with control devices other than an 
incinerator, boiler, process heater, or flare; or recovery devices 
other than an absorber, condenser, or carbon adsorber, you shall 
provide to the Administrator prior to conducting the initial 
performance test information describing the operation of the control 
device or recovery device and the parameter(s) which would indicate 
proper operation and maintenance of the device and how the parameter(s) 
are indicative of control of TOC emissions. The Administrator may 
request further information and will specify appropriate monitoring 
procedures or requirements, including operating parameters to be 
monitored, averaging times for determining compliance with the 
operating parameter limits, and ongoing calibration and quality control 
requirements.


Sec.  60.664a  What test methods and procedures must I use to determine 
compliance with the standards?

    (a) For the purpose of demonstrating compliance with the emission 
limits and standards specified in table 1 to this subpart, all affected 
facilities must be run at full operating conditions and flow rates 
during any performance test. Performance tests are not required if you 
determine compliance using a CEMS that meets the requirements outlined 
in paragraph (g) of this section.
    (1) Conduct initial performance tests no later than the date 
required by Sec.  60.8(a).
    (2) Conduct subsequent performance tests no later than 60 calendar 
months after the previous performance test.
    (b) The following methods, except as provided in Sec.  60.8(b) 
must, must be used as reference methods to determine compliance with 
the emission limit or percent reduction efficiency specified in table 1 
to this subpart for non-flare control devices and/or recovery systems.
    (1) Method 1 or 1A of appendix A-1 to this part, as appropriate, 
for selection of the sampling sites. The inlet sampling site for 
determination of vent stream molar composition or TOC (less methane and 
ethane) reduction efficiency shall be prior to the inlet of the control 
device or, if equipped with a recovery system, then prior to the inlet 
of the first recovery device in the recovery system.
    (2) Method 2, 2A, 2C, or 2D of appendix A-1 to this part, as 
appropriate, for determination of the gas volumetric flow rates.
    (3) Method 3A of appendix A-2 to this part or the manual method in 
ANSI/ASME PTC 19.10-1981 (incorporated by reference, see Sec.  
[thinsp]60.17) must be used to determine the oxygen concentration 
(%O2d) for the purposes of determining compliance with the 20 ppmv 
limit. The sampling site must be the same as that of the TOC samples, 
and the samples must be taken during the same time that the TOC samples 
are taken. The TOC concentration corrected to 3 percent O2 
(Cc) must be computed using the following equation:
Equation 1 to Paragraph (b)(3)
[GRAPHIC] [TIFF OMITTED] TR16MY24.037

Where:

Cc = Concentration of TOC corrected to 3 percent 
O2, dry basis, ppm by volume.
CTOC = Concentration of TOC (minus methane and ethane), 
dry basis, ppm by volume.
%O2d = Concentration of O2, dry basis, percent 
by volume.

    (4) Method 18 of appendix A-6 to this part to determine the 
concentration of TOC in the control device outlet or in the outlet of 
the final recovery device in a recovery system, and to determine the 
concentration of TOC in the inlet when the reduction efficiency of the 
control device or recovery system is to be determined. ASTM D6420-18 
(incorporated by reference, see Sec.  60.17) may be used in lieu of 
Method 18, if the target compounds are all known and are all listed in 
section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 may not be 
used for methane and ethane; and ASTM D6420-18 must not be used as a 
total VOC method.
    (i) The sampling time for each run must be 1 hour in which either 
an integrated sample or at least four grab samples must be taken. If 
grab sampling

[[Page 43112]]

is used then the samples must be taken at 15-minute intervals.
    (ii) The emission reduction (R) of TOC (minus methane and ethane) 
must be determined using the following equation:
Equation 2 to Paragraph (b)(4)(ii)
[GRAPHIC] [TIFF OMITTED] TR16MY24.038

Where:

R = Emission reduction, percent by weight.
Ei = Mass rate of TOC entering the control device or 
recovery system, kg/hr (lb/hr).
Eo = Mass rate of TOC discharged to the atmosphere, kg/hr 
(lb/hr).

    (iii) The mass rates of TOC (Ei, Eo) must be 
computed using the following equations:
Equations 3 and 4 to Paragraph (b)(4)(iii)
[GRAPHIC] [TIFF OMITTED] TR16MY24.039

Where:

Cij, Coj = Concentration of sample component 
``j'' of the gas stream at the inlet and outlet of the control 
device or recovery system, respectively, dry basis, ppm by volume.
Mij, Moj = Molecular weight of sample 
component ``j'' of the gas stream at the inlet and outlet of the 
control device or recovery system, respectively, g/g-mole (lb/lb-
mole).
Qi, Qo = Flow rate of gas stream at the inlet 
and outlet of the control device or recovery system, respectively, 
dscm/min (dscf/min).
K2 = 2.494 x 10-6 (1/ppm)(g-mole/scm) (kg/g) 
(min/hr) (metric units), where standard temperature for (g-mole/scm) 
is 20 [deg]C.
= 1.557 x 10-7 (1/ppm) (lb-mole/scf) (min/hr) (English 
units), where standard temperature for (lb-mole/scf) is 68 [deg]F.

    (iv) The TOC concentration (CTOC) is the sum of the 
individual components and must be computed for each run using the 
following equation:
Equation 5 to Paragraph (b)(4)(iv)
[GRAPHIC] [TIFF OMITTED] TR16MY24.040

Where:

CTOC = Concentration of TOC (minus methane and ethane), 
dry basis, ppm by volume.
Cj = Concentration of sample components ``j'', dry basis, 
ppm by volume.
n = Number of components in the sample.

    (c) The requirement for initial and subsequent performance tests 
are waived, in accordance with Sec.  60.8(b), for the following:
    (1) When a boiler or process heater with a design heat input 
capacity of 44 MW (150 million Btu/hour) or greater is used to seek to 
comply with the emission limit or percent reduction efficiency 
specified in table 1 to this subpart.
    (2) When a vent stream is introduced into a boiler or process 
heater with the primary fuel.
    (3) When a boiler or process heater burning hazardous waste is used 
for which the owner or operator:
    (i) Has been issued a final permit under 40 CFR part 270 and 
complies with the requirements of 40 CFR part 266, subpart H;
    (ii) Has certified compliance with the interim status requirements 
of 40 CFR part 266, subpart H;
    (iii) Has submitted a Notification of Compliance under 40 CFR 
63.1207(j) and complies with the requirements of 40 CFR part 63, 
subpart EEE; or
    (iv) Complies with 40 CFR part 63, subpart EEE and will submit a 
Notification of Compliance under 40 CFR 63.1207(j) by the date the 
owner or operator would have been required to submit the initial 
performance test report for this subpart.
    (4) The Administrator reserves the option to require testing at 
such other times as may be required, as provided for in section 114 of 
the Act.
    (d) For purposes of complying with the 98 weight-percent reduction 
in Sec.  60.702a(a), if the vent stream entering a boiler or process 
heater with a design capacity less than 44 MW (150 million Btu/hour) is 
introduced with the combustion air or as secondary fuel, the weight-
percent reduction of TOC (minus methane and ethane) across the 
combustion device shall be determined by comparing the TOC (minus 
methane and ethane) in all combusted vent streams, primary fuels, and 
secondary fuels with the TOC (minus methane and ethane) exiting the 
combustion device.
    (e) Any owner or operator subject to the provisions of this subpart 
seeking to demonstrate compliance with Sec.  60.660a(c)(5) must use 
Method 2, 2A, 2C, or 2D of appendix A-1 to this part as appropriate, 
for determination of volumetric flow rate. The owner or operator must 
conduct three velocity traverses and determine the volumetric flow rate 
for each traverse. If the pipe or duct is smaller than four inches in 
diameter, the owner operator may conduct the measurement at the 
centroid of the duct instead of conducting a traverse; the measurement 
period must be at least five minutes long and data must be recorded at 
least once every 30 seconds. Owners and operators who conduct the 
determination with

[[Page 43113]]

Method 2A or 2D must record volumetric flow rate every 30 seconds for 
at least five minutes.
    (f) Any owner or operator subject to the provisions of this subpart 
seeking to demonstrate compliance with Sec.  60.660a(c)(6) must use the 
following methods:
    (1) Method 1 or 1A of appendix A-1 to this part, as appropriate.
    (2) Method 2, 2A, 2C, or 2D of appendix A-1 to this part, as 
appropriate, for determination of the gas volumetric flow rates.
    (3) Method 18 of appendix A-6 to this part to determine the 
concentration of TOC. ASTM D6420-18 (incorporated by reference, see 
Sec.  60.17) may be used in lieu of Method 18, if the target compounds 
are all known and are all listed in Section 1.1 of ASTM D6420-18 as 
measurable; ASTM D6420-18 may not be used for methane and ethane; and 
ASTM D6420-18 must not be used as a total VOC method.
    (i) The sampling site must be at a location that provides a 
representative sample of the vent stream.
    (ii) Perform three test runs. The sampling time for each run must 
be 1 hour in which either an integrated sample or at least four grab 
samples must be taken. If grab sampling is used then the samples must 
be taken at 15-minute intervals.
    (iii) The mass rate of TOC (E) must be computed using the following 
equation:
Equation 6 to Paragraph (f)(3)(iii)
[GRAPHIC] [TIFF OMITTED] TR16MY24.041

Where:

Cj = Concentration of sample component ``j'' of the gas 
stream at the representative sampling location, dry basis, ppm by 
volume.
Mj = Molecular weight of sample component ``j'' of the 
gas stream at the representative sampling location, g/g-mole (lb/lb-
mole).
Q = Flow rate of gas stream at the representative sampling location, 
dscm/min (dscf/min).
K = 2.494 x 10-6 (1/ppm)(g-mole/scm) (kg/g) (min/hr) 
(metric units), where standard temperature for (g-mole/scm) is 20 
[deg]C.
= 1.557 x 10-7 (1/ppm) (lb-mole/scf) (min/hr) (English 
units), where standard temperature for (lb-mole/scf) is 68 [deg]F.

    (g) If you use a CEMS to demonstrate initial and continuous 
compliance with the TOC standard in table 1 of this subpart, each CEMS 
must be installed, operated and maintained according to the 
requirements in Sec.  60.13 and paragraphs (g)(1) through (5) of this 
section.
    (1) You must use a CEMS that is capable of measuring the target 
analyte(s) as demonstrated using either process knowledge of the 
control device inlet stream or the screening procedures of Method 18 of 
appendix A-6 to this part on the control device inlet stream. If your 
CEMS is located after a combustion device and inlet stream to that 
device includes methanol or formaldehyde, you must use a CEMS which 
meets the requirements in Performance Specification 9 or 15 of appendix 
B to this part.
    (2) Each CEMS must be installed, operated, and maintained according 
to the applicable performance specification of appendix B to this part 
and the applicable quality assurance procedures of appendix F to this 
part. Locate the sampling probe or other interface at a measurement 
location such that you obtain representative measurements of emissions 
from the affected facility.
    (3) Conduct a performance evaluation of each CEMS within 180 days 
of installation of the monitoring system. Conduct subsequent 
performance evaluations of the CEMS no later than 12 calendar months 
after the previous performance evaluation. The results each performance 
evaluation must be submitted in accordance with Sec.  60.665a(b)(1).
    (4) You must determine TOC concentration according to one of the 
following options. The span value of the TOC CEMS must be approximately 
2 times the emission standard specified in table 1 of this subpart.
    (i) For CEMS meeting the requirements of Performance Specification 
15 of appendix B to this part, determine the target analyte(s) for 
calibration using either process knowledge of the control device inlet 
stream or the screening procedures of Method 18 of appendix A-6 to this 
part on the control device inlet stream. The individual analytes used 
to quantify TOC must represent 98 percent of the expected mass of TOC 
present in the stream. Report the results of TOC as equivalent to 
carbon (C1).
    (ii) For CEMS meeting the requirements of Performance Specification 
9 of appendix B of this part, determine the target analyte(s) for 
calibration using either process knowledge of the control device inlet 
stream or the screening procedures of Method 18 of appendix A-6 to this 
part on the control device inlet stream. The individual analytes used 
to quantify TOC must represent 98 percent of the expected mass of TOC 
present in the stream. Report the results of TOC as equivalent to 
carbon (C1).
    (iii) For CEMS meeting the requirements of Performance 
Specification 8 of appendix B to this part used to monitor performance 
of a combustion device, calibrate the instrument on the predominant 
organic HAP and report the results as carbon (C1), and use Method 25A 
of appendix A-7 to this part as the reference method for the relative 
accuracy tests. You must also comply with procedure 1 of appendix F to 
this part.
    (iv) For CEMS meeting the requirements of Performance Specification 
8 of appendix B to this part used to monitor performance of a 
noncombustion device, determine the predominant organic compound using 
either process knowledge or the screening procedures of Method 18 on 
the control device inlet stream. Calibrate the monitor on the 
predominant organic compound and report the results as C1. 
Use Method 25A of appendix A-7 to this part as the reference method for 
the relative accuracy tests. You must also comply with procedure 1 of 
appendix F to this part.
    (5) You must determine stack oxygen concentration at the same 
location where you monitor TOC concentration with a CEMS that meets the 
requirements of Performance Specification 3 of appendix B to this part. 
The span value of the oxygen CEMS must be approximately 25 percent 
oxygen. Use Method 3A of appendix A-2 to this part as the reference 
method for the relative accuracy tests.
    (6) You must maintain written procedures for your CEMS. At a 
minimum, the procedures must include the information in paragraph 
(g)(6)(i) through (vi) of this section:
    (i) Description of CEMS installation location.

[[Page 43114]]

    (ii) Description of the monitoring equipment, including the 
manufacturer and model number for all monitoring equipment components 
and the span of the analyzer.
    (iii) Routine quality control and assurance procedures.
    (iv) Conditions that would trigger a CEMS performance evaluation, 
which must include, at a minimum, a newly installed CEMS; a process 
change that is expected to affect the performance of the CEMS; and the 
Administrator's request for a performance evaluation under section 114 
of the Clean Air Act.
    (v) Ongoing operation and maintenance procedures.
    (vi) Ongoing recordkeeping and reporting procedures.


Sec.  60.665a  What records must I keep and what reports must I submit?

    (a) You must notify the Administrator of the specific provisions of 
table 1 of this subpart or Sec.  60.662a(c) with which you have elected 
to comply. Notification must be submitted with the notification of 
initial start-up required by Sec.  60.7(a)(3). If you elect at a later 
date to use an alternative provision of table 1 to this subpart with 
which you will comply, then you must notify the Administrator 90 days 
before implementing a change and, upon implementing the change, you 
must conduct a performance test as specified by Sec.  60.664a within 
180 days.
    (b) If you use a non-flare control device or recovery system to 
comply with the TOC emission limit specified in table 1 to this 
subpart, then you must keep an up-to-date, readily accessible record of 
the data measured during each performance test to show compliance with 
the TOC emission limit. You must also include all of the data you use 
to comply with Sec.  60.663a(a)(2). The same data specified in this 
paragraph must also be submitted in the initial performance test 
required in Sec.  60.8 and the reports of all subsequently required 
performance tests where either the emission reduction efficiency of a 
control device or recovery system or outlet concentration of TOC is 
determined. Alternatively, you must keep records of each CEMS 
performance evaluation.
    (1) Within 60 days after the date of completing each performance 
test or CEMS performance evaluation required by this subpart, you must 
submit the results of the performance test or performance evaluation 
following the procedures specified in paragraph (k) of this section. 
Data collected using test methods and performance evaluations of CEMS 
measuring relative accuracy test audit (RATA) pollutants supported by 
the EPA's Electronic Reporting Tool (ERT) as listed on the EPA's ERT 
website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test or performance 
evaluation must be submitted in a file format generated through the use 
of the EPA's ERT. Alternatively, owners and operators may submit an 
electronic file consistent with the extensible markup language (XML) 
schema listed on the EPA's ERT website. Data collected using test 
methods and performance evaluations of CEMS measuring RATA pollutants 
that are not supported by the EPA's ERT as listed on the EPA's ERT 
website at the time of the test must be included as an attachment in 
the ERT or alternate electronic file.
    (2) If you use a boiler or process heater with a design heat input 
capacity of 44 MW (150 million Btu/hour) or greater to comply with the 
TOC emission limit specified in table 1 to this subpart, then you are 
not required to submit a report containing performance test data; 
however, you must submit a description of the location at which the 
vent stream is introduced into the boiler or process heater.
    (c) If you use a non-flare control device or recovery system to 
comply with the TOC emission limit specified in Table 1 to this 
subpart, then you must keep up-to-date, readily accessible records of 
periods of operation during which the operating parameter limits 
established during the most recent performance test are exceeded or 
periods of operation where the TOC CEMS, averaged on a 3-hour block 
basis, indicate an exceedance of the emission standard in table 1 to 
this subpart. Additionally, you must record all periods when the TOC 
CEMS is inoperable. The Administrator may at any time require a report 
of these data. Periods of operation during which the operating 
parameter limits established during the most recent performance tests 
are exceeded are defined as follows:
    (1) For absorbers:
    (i) All 3-hour periods of operation during which the average 
absorbing liquid temperature was above the maximum absorbing liquid 
temperature established during the most recent performance test.
    (ii) All 3-hour periods of operation during which the average 
absorbing liquid specific gravity was outside the exit specific gravity 
range (i.e., more than 0.1 unit above, or more than 0.1 unit below, the 
average absorbing liquid specific gravity) established during the most 
recent performance test.
    (2) For boilers or process heaters:
    (i) Whenever there is a change in the location at which the vent 
stream is introduced into the flame zone as required under Sec.  
60.663a(b).
    (ii) If the boiler or process heater has a design heat input 
capacity of less than 44 MW (150 million Btu/hr), then all 3-hour 
periods of operation during which the average firebox temperature was 
below the minimum firebox temperature during the most recent 
performance test.
    (3) For catalytic incinerators:
    (i) All 3-hour periods of operation during which the average 
temperature of the vent stream immediately before the catalyst bed is 
below the minimum temperature of the vent stream established during the 
most recent performance test.
    (ii) All 3-hour periods of operation during which the average 
temperature difference across the catalyst bed is less than the average 
temperature difference of the device established during the most recent 
performance test.
    (4) For carbon adsorbers:
    (i) All carbon bed regeneration cycles during which the total mass 
stream flow or the total volumetric stream flow was below the minimum 
flow established during the most recent performance test.
    (ii) All carbon bed regeneration cycles during which the 
temperature of the carbon bed after regeneration (and after completion 
of any cooling cycle(s)) was greater than the maximum carbon bed 
temperature (in degrees Celsius) established during the most recent 
performance test.
    (5) For condensers, all 3-hour periods of operation during which 
the average exit (product side) condenser operating temperature was 
above the maximum exit (product side) operating temperature established 
during the most recent performance test.
    (6) For scrubbers used to control halogenated vent streams:
    (i) All 3-hour periods of operation during which the average pH of 
the scrubber effluent is below the minimum pH of the scrubber effluent 
established during the most recent performance test.
    (ii) All 3-hour periods of operation during which the average 
influent liquid flow to the scrubber is below the minimum influent 
liquid flow to the scrubber established during the most recent 
performance test.
    (iii) All 3-hour periods of operation during which the average 
liquid-to-gas ratio flow of the scrubber is below the minimum liquid-
to-gas ratio of the scrubber established during the most recent 
performance test.
    (7) For thermal incinerators, all 3-hour periods of operation 
during which the average firebox temperature was

[[Page 43115]]

below the minimum firebox temperature established during the most 
recent performance test.
    (8) For all other control devices, all periods (for the averaging 
time specified by the Administrator) when the operating parameter(s) 
established under Sec.  60.663a(c) exceeded the operating limit 
established during the most recent performance test.
    (d) You must keep up to date, readily accessible continuous records 
of the flow indication specified in table 2 to this subpart, as well as 
up-to-date, readily accessible records of all periods when the vent 
stream is diverted from the control device or recovery device or has no 
flow rate, including the records as specified in paragraphs (d)(1) and 
(2) of this section.
    (1) For each flow event from a relief valve discharge subject to 
the requirements in Sec.  60.662a(b)(1), you must include an estimate 
of the volume of gas, the concentration of TOC in the gas and the 
resulting emissions of TOC that released to the atmosphere using 
process knowledge and engineering estimates.
    (2) For each flow event from a bypass line subject to the 
requirements in Sec. Sec.  60.662a(b)(2) and 60.670a(e), you must 
maintain records sufficient to determine whether or not the detected 
flow included flow requiring control. For each flow event from a bypass 
line requiring control that is released either directly to the 
atmosphere or to a control device or recovery device not meeting the 
requirements in this subpart, you must include an estimate of the 
volume of gas, the concentration of TOC in the gas and the resulting 
emissions of TOC that bypassed the control device or recovery device 
using process knowledge and engineering estimates.
    (e) If you use a boiler or process heater with a design heat input 
capacity of 44 MW (150 million Btu/hour) or greater to comply with the 
TOC emission limit specified in Table 1 to this subpart, then you must 
keep an up-to-date, readily accessible record of all periods of 
operation of the boiler or process heater. (Examples of such records 
could include records of steam use, fuel use, or monitoring data 
collected pursuant to other State or Federal regulatory requirements.)
    (f) If you use a flare to comply with the TOC emission standard 
specified in Table 1 to this subpart, then you must keep up-to-date, 
readily accessible records of all visible emission readings, heat 
content determinations, flow rate measurements, and exit velocity 
determinations made during the initial visible emissions demonstration 
required by Sec.  63.670(h) of this chapter, as applicable; and all 
periods during the compliance determination when the pilot flame or 
flare flame is absent.
    (g) For each maintenance vent opening subject to the requirements 
of Sec.  60.662a(c), you must keep the applicable records specified in 
paragraphs (g)(1) through (5) of this section.
    (1) You must maintain standard site procedures used to inventory 
equipment for safety purposes (e.g., hot work or vessel entry 
procedures) to document the procedures used to meet the requirements in 
Sec.  60.662a(c). The current copy of the procedures must be retained 
and available on-site at all times. Previous versions of the standard 
site procedures, as applicable, must be retained for five years.
    (2) If complying with the requirements of Sec.  60.662a(c)(1)(i), 
and the lower explosive limit at the time of the vessel opening exceeds 
10 percent, identification of the maintenance vent, the process units 
or equipment associated with the maintenance vent, the date of 
maintenance vent opening, and the lower explosive limit at the time of 
the vessel opening.
    (3) If complying with the requirements of Sec.  60.662a(c)(1)(ii), 
and either the vessel pressure at the time of the vessel opening 
exceeds 5 psig or the lower explosive limit at the time of the active 
purging was initiated exceeds 10 percent, identification of the 
maintenance vent, the process units or equipment associated with the 
maintenance vent, the date of maintenance vent opening, the pressure of 
the vessel or equipment at the time of discharge to the atmosphere and, 
if applicable, the lower explosive limit of the vapors in the equipment 
when active purging was initiated.
    (4) If complying with the requirements of Sec.  60.662a(c)(1)(iii), 
records of the estimating procedures used to determine the total 
quantity of VOC in the equipment and the type and size limits of 
equipment that contain less than 50 pounds of VOC at the time of 
maintenance vent opening. For each maintenance vent opening that 
contains greater than 50 pounds of VOC for which the inventory 
procedures specified in paragraph (g)(1) of this section are not 
followed or for which the equipment opened exceeds the type and size 
limits established in the records specified in this paragraph (g)(4), 
records that identify the maintenance vent, the process units or 
equipment associated with the maintenance vent, the date of maintenance 
vent opening, and records used to estimate the total quantity of VOC in 
the equipment at the time the maintenance vent was opened to the 
atmosphere.
    (5) If complying with the requirements of Sec.  60.662a(c)(1)(iv), 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, records documenting actions taken 
to comply with other applicable alternatives and why utilization of 
this alternative was required, the date of maintenance vent opening, 
the equipment pressure and lower explosive limit of the vapors in the 
equipment at the time of discharge, an indication of whether active 
purging was performed and the pressure of the equipment during the 
installation or removal of the blind if active purging was used, the 
duration the maintenance vent was open during the blind installation or 
removal process, and records used to estimate the total quantity of VOC 
in the equipment at the time the maintenance vent was opened to the 
atmosphere for each applicable maintenance vent opening.
    (h) If you seek to comply with the requirements of this subpart by 
complying with the design production capacity provision in Sec.  
60.660a(c)(4) you must keep up-to-date, readily accessible records of 
any change in equipment or process operation that increases the design 
production capacity of the process unit in which the affected facility 
is located.
    (i) If you seek to comply with the requirements of this subpart by 
complying with the flow rate cutoff in Sec.  60.660a(c)(5) or (6) you 
must keep up-to-date, readily accessible records to indicate that the 
vent stream flow rate is less than 0.008 scm/min (0.3 scf/min) or less 
than 0.001 lb/hr, and of any change in equipment or process operation 
that increases the operating vent stream flow rate, including a 
measurement of the new vent stream flow rate.
    (j) You must submit to the Administrator semiannual reports of the 
information specified in paragraphs (j)(1) through (9) of this section. 
You are exempt from the reporting requirements specified in Sec.  
60.7(c). If there are no exceedances, periods, or events specified in 
paragraphs (j)(1) through (9) of this section that occurred during the 
reporting period, then you must include a statement in your report that 
no exceedances, periods, and events specified in paragraphs (j)(1) 
through (9) of this section occurred during the reporting period. The 
initial report must be submitted within 6 months after the initial 
start-up-date. On and after July 15, 2024 or once the report template 
for

[[Page 43116]]

this subpart has been available on the Compliance and Emissions Data 
Reporting Interface (CEDRI) website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 year, whichever date is later, you 
must submit all subsequent reports using the appropriate electronic 
report template on the CEDRI website for this subpart and following the 
procedure specified in paragraph (k) of this section. The date report 
templates become available will be listed on the CEDRI website. Unless 
the Administrator or delegated state agency or other authority has 
approved a different schedule for submission of reports, the report 
must be submitted by the deadline specified in this subpart, regardless 
of the method in which the report is submitted. All semiannual reports 
must include the following general information: company name, address 
(including county), and beginning and ending dates of the reporting 
period.
    (1) Exceedances of monitored parameters recorded under paragraph 
(c) of this section. For each exceedance, the report must include a 
list of the affected facilities or equipment, the monitored parameter 
that was exceeded, the start date and time of the exceedance, the 
duration (in hours) of the exceedance, an estimate of the quantity in 
pounds of each regulated pollutant emitted over any emission limit, a 
description of the method used to estimate the emissions, the cause of 
the exceedance (including unknown cause, if applicable), as applicable, 
and the corrective action taken.
    (2) All periods recorded under paragraph (d) of this section when 
the vent stream is diverted from the control device or recovery device, 
or has no flow rate, including the information specified in paragraphs 
(j)(2)(i) through (iii) of this section.
    (i) For periods when the flow indicator is not operating, report 
the identification of the flow indicator and the start date, start 
time, and duration in hours.
    (ii) For each flow event from a relief valve discharge subject to 
the requirements in Sec.  60.662a(b)(1), the semiannual report must 
include the identification of the relief valve, the start date, start 
time, duration in hours, estimate of the volume of gas in standard 
cubic feet, the concentration of TOC in the gas in parts per million by 
volume and the resulting mass emissions of TOC in pounds that released 
to the atmosphere.
    (iii) For each flow event from a bypass line subject to the 
requirements in Sec.  60.662a(b)(2) and Sec.  670a(e)(2), the 
semiannual report must include the identification of the bypass line, 
the start date, start time, duration in hours, estimate of the volume 
of gas in standard cubic feet, the concentration of TOC in the gas in 
parts per million by volume and the resulting mass emissions of TOC in 
pounds that bypass a control device or recovery device.
    (3) All periods when a boiler or process heater was not operating 
(considering the records recorded under paragraph (e) of this section), 
including the start date, start time, and duration in hours of each 
period.
    (4) For each flare subject to the requirements in Sec.  60.669a, 
the semiannual report must include an identification of the flare and 
the items specified in Sec.  60.669a(l)(2).
    (5) For each closed vent system subject to the requirements in 
Sec.  60.670a, the semiannual report must include an identification of 
the closed vent system and the items specified in Sec.  60.670a(i).
    (6) Any change in equipment or process operation, as recorded under 
paragraph (h) of this section, that increases the design production 
capacity above the low capacity exemption level in Sec.  60.660a(c)(4) 
and the new capacity resulting from the change for the distillation 
process unit containing the affected facility. These must be reported 
as soon as possible after the change and no later than 180 days after 
the change. These reports may be submitted either in conjunction with 
semiannual reports or as a single separate report. Unless the facility 
qualifies for an exemption under Sec.  60.660a(c), the facility must 
begin compliance with the requirements set forth in Sec.  60.662a.
    (7) Any change in equipment or process operation that increases the 
operating vent stream flow rate above the low flow exemption level in 
Sec.  60.660a(c)(5) or (6), including a measurement of the new vent 
stream flow rate, as recorded under paragraph (i) of this section. 
These must be reported as soon as possible after the change and no 
later than 180 days after the change. These reports may be submitted 
either in conjunction with semiannual reports or as a single separate 
report. A performance test must be completed with the same time period 
to verify the recalculated flow value. The performance test is subject 
to the requirements of Sec.  60.8 and must be submitted according to 
paragraph (b)(1) of this section. Unless the facility qualifies for an 
exemption under Sec.  60.660a(c), the facility must begin compliance 
with the requirements set forth in Sec.  60.662a.
    (8) Exceedances of the emission standard in Table 1 of this subpart 
as indicated by a 3-hour average of the TOC CEMS and recorded under 
paragraph (c) of this section. For each exceedance, the report must 
include a list of the affected facilities or equipment, the start date 
and time of the exceedance, the duration (in hours) of the exceedance, 
an estimate of the quantity in pounds of each regulated pollutant 
emitted over the emission limit, a description of the method used to 
estimate the emissions, the cause of the exceedance (including unknown 
cause, if applicable), as applicable, and the corrective action taken.
    (9) Periods when the TOC CEMS was inoperative. For each period, the 
report must include a list of the affected facilities or equipment, the 
start date and time of the period, the duration (in hours) of the 
period, the cause of the inoperability (including unknown cause, if 
applicable), as applicable, and the corrective action taken.
    (k) If you are required to submit notifications or reports 
following the procedure specified in this paragraph (k), you must 
submit notifications or reports to the EPA via CEDRI, which can be 
accessed through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/). The EPA will make all the information submitted through 
CEDRI available to the public without further notice to you. Do not use 
CEDRI to submit information you claim as CBI. Although we do not expect 
persons to assert a claim of CBI, if you wish to assert a CBI claim for 
some of the information in the report or notification, you must submit 
a complete file in the format specified in this subpart, including 
information claimed to be CBI, to the EPA following the procedures in 
paragraphs (k)(1) and (2) of this section. Clearly mark the part or all 
of the information that you claim to be CBI. Information not marked as 
CBI may be authorized for public release without prior notice. 
Information marked as CBI will not be disclosed except in accordance 
with procedures set forth in 40 CFR part 2. All CBI claims must be 
asserted at the time of submission. Anything submitted using CEDRI 
cannot later be claimed CBI. Furthermore, under CAA section 114(c), 
emissions data is not entitled to confidential treatment, and the EPA 
is required to make emissions data available to the public. Thus, 
emissions data will not be protected as CBI and will be made publicly 
available. You must submit the same file submitted to the CBI office 
with the CBI omitted to the EPA via the EPA's CDX as described earlier 
in this paragraph (k).
    (1) The preferred method to receive CBI is for it to be transmitted

[[Page 43117]]

electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
[email protected], and as described above, should include clear CBI 
markings. ERT files should be flagged to the attention of the Group 
Leader, Measurement Policy Group; all other files should be flagged to 
the attention of the SOCMI NSPS Sector Lead. If assistance is needed 
with submitting large electronic files that exceed the file size limit 
for email attachments, and if you do not have your own file sharing 
service, please email [email protected] to request a file transfer link.
    (2) If you cannot transmit the file electronically, you may send 
CBI information through the postal service to the following address: 
OAQPS Document Control Officer (C404-02), OAQPS, U.S. Environmental 
Protection Agency, 109 T.W. Alexander Drive, P.O. Box 12055, Research 
Triangle Park, North Carolina 27711. ERT files should be sent to the 
attention of the Group Leader, Measurement Policy Group, and all other 
files should be sent to the attention of the SOCMI NSPS Sector Lead. 
The mailed CBI material should be double wrapped and clearly marked. 
Any CBI markings should not show through the outer envelope.
    (l) If you are required to electronically submit notifications or 
reports through CEDRI in the EPA's CDX, you may assert a claim of EPA 
system outage for failure to timely comply with the electronic 
submittal requirement. To assert a claim of EPA system outage, you must 
meet the requirements outlined in paragraphs (l)(1) through (7) of this 
section.
    (1) You must have been or will be precluded from accessing CEDRI 
and submitting a required report within the time prescribed due to an 
outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (5) You must provide to the Administrator a written description 
identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (m) If you are required to electronically submit notifications or 
reports through CEDRI in the EPA's CDX, you may assert a claim of force 
majeure for failure to timely comply with the electronic submittal 
requirement. To assert a claim of force majeure, you must meet the 
requirements outlined in paragraphs (m)(1) through (5) of this section.
    (1) You may submit a claim if a force majeure event is about to 
occur, occurs, or has occurred or there are lingering effects from such 
an event within the period of time beginning five business days prior 
to the date the submission is due. For the purposes of this section, a 
force majeure event is defined as an event that will be or has been 
caused by circumstances beyond the control of the affected facility, 
its contractors, or any entity controlled by the affected facility that 
prevents you from complying with the requirement to submit a report 
electronically within the time period prescribed. Examples of such 
events are acts of nature (e.g., hurricanes, earthquakes, or floods), 
acts of war or terrorism, or equipment failure or safety hazard beyond 
the control of the affected facility (e.g., large scale power outage).
    (2) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (3) You must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.
    (n) The requirements of paragraph (j) of this section remain in 
force until and unless EPA, in delegating enforcement authority to a 
State under section 111(c) of the Act, approves reporting requirements 
or an alternative means of compliance surveillance adopted by such 
State. In that event, affected sources within the State will be 
relieved of the obligation to comply with paragraph (j) of this 
section, provided that they comply with the requirements established by 
the State. The EPA will not approve a waiver of electronic reporting to 
the EPA in delegating enforcement authority. Thus, electronic reporting 
to the EPA cannot be waived, and as such, the provisions of this 
paragraph cannot be used to relieve owners or operators of affected 
facilities of the requirement to submit the electronic reports required 
in this section to the EPA.
    (o) If you seek to demonstrate compliance with Sec.  60.660(c)(4), 
then you must submit to the Administrator an initial report detailing 
the design production capacity of the process unit.
    (p) If you seek to demonstrate compliance with Sec.  60.660(c)(5) 
or (6), then you must submit to the Administrator, following the 
procedures in paragraph (b)(1) of this section, an initial report 
including a flow rate measurement using the test methods specified in 
Sec.  60.664a.
    (q) The Administrator will specify appropriate reporting and 
recordkeeping requirements where the owner or operator of an affected 
facility complies with the standards specified under Sec.  60.662a 
other than as provided under Sec.  60.663a.
    (r) Any records required to be maintained by this subpart that are 
submitted electronically via the EPA's CEDRI may be maintained in 
electronic format. This ability to maintain electronic copies does not 
affect the requirement for facilities to make records, data, and 
reports available upon request to a delegated air agency or the EPA as 
part of an on-site compliance evaluation.


Sec.  60.666a  What do the terms associated with reconstruction mean 
for this subpart?

    For purposes of this subpart ``fixed capital cost of the new 
components,'' as

[[Page 43118]]

used in Sec.  60.15, includes the fixed capital cost of all depreciable 
components which are or will be replaced pursuant to all continuous 
programs of component replacement which are commenced within any 2-year 
period following April 25, 2023. For purposes of this paragraph, 
``commenced'' means that you have undertaken a continuous program of 
component replacement or that you have entered into a contractual 
obligation to undertake and complete, within a reasonable time, a 
continuous program of component replacement.


Sec.  60.667a  What are the chemicals that I must produce to be 
affected by subpart NNNa?

------------------------------------------------------------------------
                    Chemical name                           CAS No.*
------------------------------------------------------------------------
Acetaldehyde.........................................            75-07-0
Acetaldol............................................           107-89-1
Acetic acid..........................................            64-19-7
Acetic anhydride.....................................           108-24-7
Acetone..............................................            67-64-1
Acetone cyanohydrin..................................            75-86-5
Acetylene............................................            74-86-2
Acrylic acid.........................................            79-10-7
Acrylonitrile........................................           107-13-1
Adipic acid..........................................           124-04-9
Adiponitrile.........................................           111-69-3
Alcohols, C-11 or lower, mixtures....................  .................
Alcohols, C-12 or higher, mixtures...................  .................
Allyl chloride.......................................           107-05-1
Amylene..............................................           513-35-9
Amylenes, mixed......................................  .................
Aniline..............................................            62-53-3
Benzene..............................................            71-43-2
Benzenesulfonic acid.................................            98-11-3
Benzenesulfonic acid C10-16-alkyl derivatives, sodium         68081-81-2
 salts...............................................
Benzoic acid, tech...................................            65-85-0
Benzyl chloride......................................           100-44-7
Biphenyl.............................................            92-52-4
Bisphenol A..........................................            80-05-7
Brometone............................................            76-08-4
1,3-Butadiene........................................           106-99-0
Butadiene and butene fractions.......................  .................
n-Butane.............................................           106-97-8
1,4-Butanediol.......................................           110-63-4
Butanes, mixed.......................................  .................
1-Butene.............................................           106-98-9
2-Butene.............................................         25167-67-3
Butenes, mixed.......................................  .................
n-Butyl acetate......................................           123-86-4
Butyl acrylate.......................................           141-32-2
n-Butyl alcohol......................................            71-36-3
sec-Butyl alcohol....................................            78-92-2
tert-Butyl alcohol...................................            75-65-0
Butylbenzyl phthalate................................            85-68-7
Butylene glycol......................................           107-88-0
tert-Butyl hydroperoxide.............................            75-91-2
2-Butyne-1,4-diol....................................           110-65-6
Butyraldehyde........................................           123-72-8
Butyric anhydride....................................           106-31-0
Caprolactam..........................................           105-60-2
Carbon disulfide.....................................            75-15-0
Carbon tetrabromide..................................           558-13-4
Carbon tetrachloride.................................            56-23-5
Chlorobenzene........................................           108-90-7
2-Chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine          1912-24-9
Chloroform...........................................            67-66-3
p-Chloronitrobenzene.................................           100-00-5
Chloroprene..........................................           126-99-8
Citric acid..........................................            77-92-9
Crotonaldehyde.......................................          4170-30-0
Crotonic acid........................................          3724-65-0
Cumene...............................................            98-82-8
Cumene hydroperoxide.................................            80-15-9
Cyanuric chloride....................................           108-77-0
Cyclohexane..........................................           110-82-7
Cyclohexane, oxidized................................         68512-15-2
Cyclohexanol.........................................           108-93-0
Cyclohexanone........................................           108-94-1
Cyclohexanone oxime..................................           100-64-1
Cyclohexene..........................................           110-83-8
1,3-Cyclopentadiene..................................           542-92-7

[[Page 43119]]

 
Cyclopropane.........................................            75-19-4
Diacetone alcohol....................................           123-42-2
Dibutanized aromatic concentrate.....................  .................
1,4-Dichlorobutene...................................           110-57-6
3,4-Dichloro-1-butene................................         64037-54-3
Dichlorodifluoromethane..............................            75-71-8
Dichlorodimethylsilane...............................            75-78-5
Dichlorofluoromethane................................            75-43-4
Dichlorohydrin.......................................            96-23-1
Diethanolamine.......................................           111-42-2
Diethylbenzene.......................................         25340-17-4
Diethylene glycol....................................           111-46-6
Di-n-heptyl-n-nonyl undecyl phthalate................            85-68-7
Di-isodecyl phthalate................................         26761-40-0
Diisononyl phthalate.................................         28553-12-0
Dimethylamine........................................           124-40-3
Dimethyl terephthalate...............................           120-61-6
2,4-Dinitrotoluene...................................           121-14-2
2,4-(and 2,6)-dinitrotoluene.........................           121-14-2
                                                                606-20-2
Dioctyl phthalate....................................           117-81-7
Dodecene.............................................         25378-22-7
Dodecylbenzene, non linear...........................  .................
Dodecylbenzenesulfonic acid..........................         27176-87-0
Dodecylbenzenesulfonic acid, sodium salt.............         25155-30-0
Epichlorohydrin......................................           106-89-8
Ethanol..............................................            64-17-5
Ethanolamine.........................................           141-43-5
Ethyl acetate........................................           141-78-6
Ethyl acrylate.......................................           140-88-5
Ethylbenzene.........................................           100-41-4
Ethyl chloride.......................................            75-00-3
Ethyl cyanide........................................           107-12-0
Ethylene.............................................            74-85-1
Ethylene dibromide...................................           106-93-4
Ethylene dichloride..................................           107-06-2
Ethylene glycol......................................           107-21-1
Ethylene glycol monobutyl............................           111-76-2
Ethylene glycol monoethyl ether......................           110-80-5
Ethylene glycol monoethyl ether acetate..............           111-15-9
Ethylene glycol monomethyl ether.....................           109-86-4
Ethylene oxide.......................................            75-21-8
2-Ethylhexanal.......................................         26266-68-2
2-Ethylhexyl alcohol.................................           104-76-7
(2-Ethylhexyl) amine.................................           104-75-6
Ethylmethylbenzene...................................         25550-14-5
6-Ethyl-1,2,3,4-tetrahydro 9,10-anthracenedione......         15547-17-8
Formaldehyde.........................................            50-00-0
Glycerol.............................................            56-81-5
n-Heptane............................................           142-82-5
Heptenes (mixed).....................................  .................
Hexadecyl chloride...................................  .................
Hexamethylene diamine................................           124-09-4
Hexamethylene diamine adipate........................          3323-53-3
Hexamethylenetetramine...............................           100-97-0
Hexane...............................................           110-54-3
2-Hexenedinitrile....................................         13042-02-9
3-Hexenedinitrile....................................          1119-85-3
Hydrogen cyanide.....................................            74-90-8
Isobutane............................................            75-28-5
Isobutanol...........................................            78-83-1
Isobutylene..........................................           115-11-7
Isobutyraldehyde.....................................            78-84-2
Isodecyl alcohol.....................................         25339-17-7
Isooctyl alcohol.....................................         26952-21-6
Isopentane...........................................            78-78-4
Isophthalic acid.....................................           121-91-5
Isoprene.............................................            78-79-5
Isopropanol..........................................            67-63-0
Ketene...............................................           463-51-4
Linear alcohols, ethoxylated, mixed..................  .................
Linear alcohols, ethoxylated, and sulfated, sodium     .................
 salt, mixed.........................................
Linear alcohols, sulfated, sodium salt, mixed........  .................
Linear alkylbenzene..................................           123-01-3

[[Page 43120]]

 
Magnesium acetate....................................           142-72-3
Maleic anhydride.....................................           108-31-6
Melamine.............................................           108-78-1
Mesityl oxide........................................           141-79-7
Methacrylonitrile....................................           126-98-7
Methanol.............................................            67-56-1
Methylamine..........................................            74-89-5
ar-Methylbenzenediamine..............................         25376-45-8
Methyl chloride......................................            74-87-3
Methylene chloride...................................            75-09-2
Methyl ethyl ketone..................................            78-93-3
Methyl iodide........................................            74-88-4
Methyl isobutyl ketone...............................           108-10-1
Methyl methacrylate..................................            80-62-6
2-Methylpentane......................................           107-83-5
1-Methyl-2-pyrrolidone...............................           872-50-4
Methyl tert-butyl ether..............................  .................
Naphthalene..........................................            91-20-3
Nitrobenzene.........................................            98-95-3
1-Nonene.............................................         27215-95-8
Nonyl alcohol........................................           143-08-8
Nonylphenol..........................................         25154-52-3
Nonylphenol, ethoxylated.............................          9016-45-9
Octene...............................................         25377-83-7
Oil-soluble petroleum sulfonate, calcium salt........  .................
Oil-soluble petroleum sulfonate, sodium salt.........  .................
Pentaerythritol......................................           115-77-5
n-Pentane............................................           109-66-0
3-Pentenenitrile.....................................          4635-87-4
Pentenes, mixed......................................           109-67-1
Perchloroethylene....................................           127-18-4
Phenol...............................................           108-95-2
1-Phenylethyl hydroperoxide..........................          3071-32-7
Phenylpropane........................................           103-65-1
Phosgene.............................................            75-44-5
Phthalic anhydride...................................            85-44-9
Propane..............................................            74-98-6
Propionaldehyde......................................           123-38-6
Propionic acid.......................................            79-09-4
Propyl alcohol.......................................            71-23-8
Propylene............................................           115-07-1
Propylene chlorohydrin...............................            78-89-7
Propylene glycol.....................................            57-55-6
Propylene oxide......................................            75-56-9
Sodium cyanide.......................................           143-33-9
Sorbitol.............................................            50-70-4
Styrene..............................................           100-42-5
Terephthalic acid....................................           100-21-0
1,1,2,2-Tetrachloroethane............................            79-34-5
Tetraethyl lead......................................            78-00-2
Tetrahydrofuran......................................           109-99-9
Tetra (methyl-ethyl) lead............................  .................
Tetramethyl lead.....................................            75-74-1
Toluene..............................................           108-88-3
Toluene-2,4-diamine..................................            95-80-7
Toluene-2,4-(and, 2,6)-diisocyanate (80/20 mixture)..         26471-62-5
Tribromomethane......................................            75-25-2
1,1,1-Trichloroethane................................            71-55-6
1,1,2-Trichloroethane................................            79-00-5
Trichloroethylene....................................            79-01-6
Trichlorofluoromethane...............................            75-69-4
1,1,2-Trichloro-1,2,2-trifluoroethane................            76-13-1
Triethanolamine......................................           102-71-6
Triethylene glycol...................................           112-27-6
Vinyl acetate........................................           108-05-4
Vinyl chloride.......................................            75-01-4
Vinylidene chloride..................................            75-35-4
m-Xylene.............................................           108-38-3
o-Xylene.............................................            95-47-6
p-Xylene.............................................           106-42-3
Xylenes (mixed)......................................          1330-20-7

[[Page 43121]]

 
m-Xylenol............................................           576-26-1
------------------------------------------------------------------------
* CAS numbers refer to the Chemical Abstracts Registry numbers assigned
  to specific chemicals, isomers, or mixtures of chemicals. Some isomers
  or mixtures that are covered by the standards do not have CAS numbers
  assigned to them. The standards apply to all of the chemicals listed,
  whether CAS numbers have been assigned or not.

Sec.  60.668a  [Reserved]


Sec.  60.669a  What are my requirements if I use a flare to comply with 
this subpart?

    (a) If you use a flare to comply with the TOC emission standard 
specified in Table 1 to this subpart, then you must meet the applicable 
requirements for flares as specified in Sec. Sec.  63.670 and 63.671 of 
this chapter, including the provisions in tables 12 and 13 to part 63, 
subpart CC, of this chapter, except as specified in paragraphs (b) 
through (o) of this section. This requirement also applies to any flare 
using fuel gas from a fuel gas system, of which 50 percent or more of 
the fuel gas is derived from an affected facility, as determined on an 
annual average basis. For purposes of compliance with this paragraph 
(a), the following terms are defined in Sec.  63.641 of this chapter: 
Assist air, assist steam, center steam, combustion zone, combustion 
zone gas, flare, flare purge gas, flare supplemental gas, flare sweep 
gas, flare vent gas, lower steam, net heating value, perimeter assist 
air, pilot gas, premix assist air, total steam, and upper steam.
    (b) When determining compliance with the pilot flame requirements 
specified in Sec.  63.670(b) and (g) of this chapter, substitute 
``pilot flame or flare flame'' for each occurrence of ``pilot flame.''
    (c) When determining compliance with the flare tip velocity and 
combustion zone operating limits specified in Sec.  63.670(d) and (e) 
of this chapter, the requirement effectively applies starting with the 
15-minute block that includes a full 15 minutes of the flaring event. 
You are required to demonstrate compliance with the velocity and NHVcz 
requirements starting with the block that contains the fifteenth minute 
of a flaring event. You are not required to demonstrate compliance for 
the previous 15-minute block in which the event started and contained 
only a fraction of flow.
    (d) Instead of complying with Sec.  63.670(o)(2)(i) of this 
chapter, you must develop and implement the flare management plan no 
later than startup for a new flare that commenced construction on or 
after April 25, 2023.
    (e) Instead of complying with Sec.  63.670(o)(2)(iii) of this 
chapter, if required to develop a flare management plan and submit it 
to the Administrator, then you must also submit all versions of the 
plan in portable document format (PDF) following the procedures 
specified in Sec.  60.665a(k).
    (f) Section 63.670(o)(3)(ii) of this chapter and all references to 
it do not apply. Instead, you must comply with the maximum flare tip 
velocity operating limit at all times.
    (g) Substitute ``affected facility'' for each occurrence of 
``petroleum refinery.''
    (h) Each occurrence of ``refinery'' does not apply.
    (i) If a pressure-assisted multi-point flare is used as a control 
device, then you must meet the following conditions:
    (1) You are not required to comply with the flare tip velocity 
requirements in Sec.  63.670(d) and (k) of this chapter;
    (2) The NHVcz for pressure-assisted mulit-point flares is 800 Btu/
scf;
    (3) You must determine the 15-minute block average NHVvg using only 
the direct calculation method specified in in Sec.  63.670(l)(5)(ii) of 
this chapter;
    (4) Instead of complying with Sec.  63.670(b) and (g) of this 
chapter, if a pressure-assisted multi-point flare uses cross-lighting 
on a stage of burners rather than having an individual pilot flame on 
each burner, then you must operate each stage of the pressure-assisted 
multi-point flare with a flame present at all times when regulated 
material is routed to that stage of burners. Each stage of burners that 
cross-lights in the pressure-assisted multi-point flare must have at 
least two pilots with at least one continuously lit and capable of 
igniting all regulated material that is routed to that stage of 
burners. Each 15-minute block during which there is at least one minute 
where no pilot flame is present on a stage of burners when regulated 
material is routed to the flare is a deviation of the standard. 
Deviations in different 15-minute blocks from the same event are 
considered separate deviations. The pilot flame(s) on each stage of 
burners that use cross-lighting must be continuously monitored by a 
thermocouple or any other equivalent device used to detect the presence 
of a flame;
    (5) Unless you choose to conduct a cross-light performance 
demonstration as specified in this paragraph (i)(5), you must ensure 
that if a stage of burners on the flare uses cross-lighting, that the 
distance between any two burners in series on that stage is no more 
than 6 feet when measured from the center of one burner to the next 
burner. A distance greater than 6 feet between any two burners in 
series may be used provided you conduct a performance demonstration 
that confirms the pressure-assisted multi-point flare will cross-light 
a minimum of three burners and the spacing between the burners and 
location of the pilot flame must be representative of the projected 
installation. The compliance demonstration must be approved by the 
permitting authority and a copy of this approval must be maintained 
onsite. The compliance demonstration report must include: a protocol 
describing the test methodology used, associated test method QA/QC 
parameters, the waste gas composition and NHVcz of the gas tested, the 
velocity of the waste gas tested, the pressure-assisted multi-point 
flare burner tip pressure, the time, length, and duration of the test, 
records of whether a successful cross-light was observed over all of 
the burners and the length of time it took for the burners to cross-
light, records of maintaining a stable flame after a successful cross-
light and the duration for which this was observed, records of any 
smoking events during the cross-light, waste gas temperature, 
meteorological conditions (e.g., ambient temperature, barometric 
pressure, wind speed and direction, and relative humidity), and whether 
there were any observed flare flameouts; and
    (6) You must install and operate pressure monitor(s) on the main 
flare header, as well as a valve position indicator monitoring system 
for each staging valve to ensure that the flare operates within the 
proper range of conditions as specified by the manufacturer. The 
pressure monitor must meet the requirements in table 13 to part 63, 
subpart CC, of this chapter.
    (7) If a pressure-assisted multi-point flare is operating under the 
requirements of an approved alternative means of emission limitations, 
you must either continue to comply with the terms of the alternative 
means of emission limitations or comply with the provisions in 
paragraphs (i)(1) through (6) of this section.
    (j) If you choose to determine compositional analysis for net 
heating value with a continuous process mass

[[Page 43122]]

spectrometer, then you must comply with the requirements specified in 
paragraphs (j)(1) through (7) of this section.
    (1) You must meet the requirements in Sec.  63.671(e)(2) of this 
chapter. You may augment the minimum list of calibration gas components 
found in Sec.  63.671(e)(2) with compounds found during a pre-survey or 
known to be in the gas through process knowledge.
    (2) Calibration gas cylinders must be certified to an accuracy of 2 
percent and traceable to National Institute of Standards and Technology 
(NIST) standards.
    (3) For unknown gas components that have similar analytical mass 
fragments to calibration compounds, you may report the unknowns as an 
increase in the overlapped calibration gas compound. For unknown 
compounds that produce mass fragments that do not overlap calibration 
compounds, you may use the response factor for the nearest molecular 
weight hydrocarbon in the calibration mix to quantify the unknown 
component's NHVvg.
    (4) You may use the response factor for n-pentane to quantify any 
unknown components detected with a higher molecular weight than n-
pentane.
    (5) You must perform an initial calibration to identify mass 
fragment overlap and response factors for the target compounds.
    (6) You must meet applicable requirements in Performance 
Specification 9 of appendix B of this part, for continuous monitoring 
system acceptance including, but not limited to, performing an initial 
multi-point calibration check at three concentrations following the 
procedure in Section 10.1 and performing the periodic calibration 
requirements listed for gas chromatographs in table 13 to part 63, 
subpart CC, of this chapter, for the process mass spectrometer. You may 
use the alternative sampling line temperature allowed under Net Heating 
Value by Gas Chromatograph in table 13 to part 63, subpart CC, of this 
chapter.
    (7) The average instrument calibration error (CE) for each 
calibration compound at any calibration concentration must not differ 
by more than 10 percent from the certified cylinder gas value. The CE 
for each component in the calibration blend must be calculated using 
equation 1 to this paragraph (j)(7).

Equation 1 to Paragraph (j)(7)
[GRAPHIC] [TIFF OMITTED] TR16MY24.042

Where:

Cm = Average instrument response (ppm)
Ca = Certified cylinder gas value (ppm)

    (k) If you use a gas chromatograph or mass spectrometer for 
compositional analysis for net heating value, then you may choose to 
use the CE of NHVmeasured versus the cylinder tag value NHV 
as the measure of agreement for daily calibration and quarterly audits 
in lieu of determining the compound-specific CE. The CE for NHV at any 
calibration level must not differ by more than 10 percent from the 
certified cylinder gas value. The CE must be calculated using equation 
2 to this paragraph (k).

Equation 2 to Paragraph (k)
[GRAPHIC] [TIFF OMITTED] TR16MY24.043

Where:

NHVmeasured = Average instrument response (Btu/scf)
NHVa = Certified cylinder gas value (Btu/scf)

    (l) Instead of complying with Sec.  63.670(q) of this chapter, you 
must comply with the reporting requirements specified in paragraphs 
(l)(1) and (2) of this section.
    (1) The notification requirements specified in Sec.  60.665a(a).
    (2) The semiannual report specified in Sec.  60.665a(j)(4) must 
include the items specified in paragraphs (l)(2)(i) through (vi) of 
this section.
    (i) Records as specified in paragraph (m)(1) of this section for 
each 15-minute block during which there was at least one minute when 
regulated material is routed to a flare and no pilot flame or flare 
flame is present. Include the start and stop time and date of each 15-
minute block.
    (ii) Visible emission records as specified in paragraph (m)(2)(iv) 
of this section for each period of 2 consecutive hours during which 
visible emissions exceeded a total of 5 minutes.
    (iii) The periods specified in paragraph (m)(6) of this section. 
Indicate the date and start and end times for each period, and the net 
heating value operating parameter(s) determined following the methods 
in Sec.  63.670(k) through (n) of this chapter as applicable.
    (iv) For flaring events meeting the criteria in Sec.  63.670(o)(3) 
of this chapter and paragraph (f) of this section:
    (A) The start and stop time and date of the flaring event.
    (B) The length of time in minutes for which emissions were visible 
from the flare during the event.
    (C) For steam-assisted, air-assisted, and non-assisted flares, the 
start date, start time, and duration in minutes for periods of time 
that the flare tip velocity exceeds the maximum flare tip velocity 
determined using the methods in Sec.  63.670(d)(2) of this chapter and 
the maximum 15-minute block average flare tip velocity in ft/sec 
recorded during the event.
    (D) Results of the root cause and corrective actions analysis 
completed during the reporting period, including the corrective actions 
implemented during the reporting period and, if applicable, the 
implementation schedule for planned corrective actions to be 
implemented subsequent to the reporting period.
    (v) For pressure-assisted multi-point flares, the periods of time 
when the pressure monitor(s) on the main flare header show the burners 
operating outside the range of the manufacturer's specifications. 
Indicate the date and start and end times for each period.
    (vi) For pressure-assisted multi-point flares, the periods of time 
when the staging valve position indicator monitoring system indicates a 
stage should not be in operation and is or when a stage should be in 
operation and is not. Indicate the date and start and end times for 
each period.
    (m) Instead of complying with Sec.  63.670(p) of this chapter, you 
must keep the flare monitoring records specified in paragraphs (m)(1) 
through (14) of this section.
    (1) Retain records of the output of the monitoring device used to 
detect the presence of a pilot flame or flare flame as required in 
Sec.  63.670(b) of this chapter

[[Page 43123]]

and the presence of a pilot flame as required in paragraph (i)(4) of 
this section for a minimum of 2 years. Retain records of each 15-minute 
block during which there was at least one minute that no pilot flame or 
flare flame is present when regulated material is routed to a flare for 
a minimum of 5 years. For a pressure-assisted multi-point flare that 
uses cross-lighting, retain records of each 15-minute block during 
which there was at least one minute that no pilot flame is present on 
each stage when regulated material is routed to a flare for a minimum 
of 5 years. You may reduce the collected minute-by-minute data to a 15-
minute block basis with an indication of whether there was at least one 
minute where no pilot flame or flare flame was present.
    (2) Retain records of daily visible emissions observations as 
specified in paragraphs (m)(2)(i) through (iv) of this section, as 
applicable, for a minimum of 3 years.
    (i) To determine when visible emissions observations are required, 
the record must identify all periods when regulated material is vented 
to the flare.
    (ii) If visible emissions observations are performed using Method 
22 of appendix A-7 of this part, then the record must identify whether 
the visible emissions observation was performed, the results of each 
observation, total duration of observed visible emissions, and whether 
it was a 5-minute or 2-hour observation. Record the date and start time 
of each visible emissions observation.
    (iii) If a video surveillance camera is used pursuant to Sec.  
63.670(h)(2) of this chapter, then the record must include all video 
surveillance images recorded, with time and date stamps.
    (iv) For each 2-hour period for which visible emissions are 
observed for more than 5 minutes in 2 consecutive hours, then the 
record must include the date and start and end time of the 2-hour 
period and an estimate of the cumulative number of minutes in the 2-
hour period for which emissions were visible.
    (3) The 15-minute block average cumulative flows for flare vent gas 
and, if applicable, total steam, perimeter assist air, and premix 
assist air specified to be monitored under Sec.  63.670(i) of this 
chapter, along with the date and time interval for the 15-minute block. 
If multiple monitoring locations are used to determine cumulative vent 
gas flow, total steam, perimeter assist air, and premix assist air, 
then retain records of the 15-minute block average flows for each 
monitoring location for a minimum of 2 years, and retain the 15-minute 
block average cumulative flows that are used in subsequent calculations 
for a minimum of 5 years. If pressure and temperature monitoring is 
used, then retain records of the 15-minute block average temperature, 
pressure, and molecular weight of the flare vent gas or assist gas 
stream for each measurement location used to determine the 15-minute 
block average cumulative flows for a minimum of 2 years, and retain the 
15-minute block average cumulative flows that are used in subsequent 
calculations for a minimum of 5 years.
    (4) The flare vent gas compositions specified to be monitored under 
Sec.  63.670(j) of this chapter. Retain records of individual component 
concentrations from each compositional analysis for a minimum of 2 
years. If an NHVvg analyzer is used, retain records of the 15-minute 
block average values for a minimum of 5 years.
    (5) Each 15-minute block average operating parameter calculated 
following the methods specified in Sec.  63.670(k) through (n) this 
chapter, as applicable.
    (6) All periods during which operating values are outside of the 
applicable operating limits specified in Sec.  63.670(d) through (f) of 
this chapter and paragraph (i) of this section when regulated material 
is being routed to the flare.
    (7) All periods during which you do not perform flare monitoring 
according to the procedures in Sec.  63.670(g) through (j) of this 
chapter.
    (8) For pressure-assisted multi-point flares, if a stage of burners 
on the flare uses cross-lighting, then a record of any changes made to 
the distance between burners.
    (9) For pressure-assisted multi-point flares, all periods when the 
pressure monitor(s) on the main flare header show burners are operating 
outside the range of the manufacturer's specifications. Indicate the 
date and time for each period, the pressure measurement, the stage(s) 
and number of burners affected, and the range of manufacturer's 
specifications.
    (10) For pressure-assisted multi-point flares, all periods when the 
staging valve position indicator monitoring system indicates a stage of 
the pressure-assisted multi-point flare should not be in operation and 
when a stage of the pressure-assisted multi-point flare should be in 
operation and is not. Indicate the date and time for each period, 
whether the stage was supposed to be open, but was closed or vice 
versa, and the stage(s) and number of burners affected.
    (11) Records of periods when there is flow of vent gas to the 
flare, but when there is no flow of regulated material to the flare, 
including the start and stop time and dates of periods of no regulated 
material flow.
    (12) Records when the flow of vent gas exceeds the smokeless 
capacity of the flare, including start and stop time and dates of the 
flaring event.
    (13) Records of the root cause analysis and corrective action 
analysis conducted as required in Sec.  63.670(o)(3) of this chapter 
and paragraph (f) of this section, including an identification of the 
affected flare, the date and duration of the event, a statement noting 
whether the event resulted from the same root cause(s) identified in a 
previous analysis and either a description of the recommended 
corrective action(s) or an explanation of why corrective action is not 
necessary under Sec.  63.670(o)(5)(i) of this chapter.
    (14) For any corrective action analysis for which implementation of 
corrective actions are required in Sec.  63.670(o)(5) of this chapter, 
a description of the corrective action(s) completed within the first 45 
days following the discharge and, for action(s) not already completed, 
a schedule for implementation, including proposed commencement and 
completion dates.
    (n) You may elect to comply with the alternative means of emissions 
limitation requirements specified in Sec.  63.670(r) of this chapter in 
lieu of the requirements in Sec.  63.670(d) through (f) of this 
chapter, as applicable. However, instead of complying with Sec.  
63.670(r)(3)(iii) of this chapter, you must also submit the alternative 
means of emissions limitation request to the following address: U.S. 
Environmental Protection Agency, Office of Air Quality Planning and 
Standards, Sector Policies and Programs Division, U.S. EPA Mailroom 
(C404-02), Attention: SOCMI NSPS Sector Lead, 4930 Old Page Rd., 
Durham, NC 27703.
    (o) The referenced provisions specified in paragraphs (o)(1) 
through (4) of this section do not apply when demonstrating compliance 
with this section.
    (1) Section 63.670(o)(4)(iv) of this chapter.
    (2) The last sentence of Sec.  63.670(o)(6) of this chapter.
    (3) The phrase ``that were not caused by a force majeure event'' in 
Sec.  63.670(o)(7)(ii) of this chapter.
    (4) The phrase ``that were not caused by a force majeure event'' in 
Sec.  63.670(o)(7)(iv) of this chapter.


Sec.  60.670a  What are my requirements for closed vent systems?

    (a) Except as provided in paragraphs (f) and (g) of this section, 
you must inspect each closed vent system

[[Page 43124]]

according to the procedures and schedule specified in paragraphs (a)(1) 
through (3) of this section.
    (1) Conduct an initial inspection according to the procedures in 
paragraph (b) of this section unless the closed vent system is operated 
and maintained under negative pressure;
    (2) Conduct annual inspections according to the procedures in 
paragraph (b) of this section unless the closed vent system is operated 
and maintained under negative pressure; and
    (3) Conduct annual inspections for visible, audible, or olfactory 
indications of leaks.
    (b) You must inspect each closed vent system according to the 
procedures specified in paragraphs (b)(1) through (6) of this section.
    (1) Inspections must be conducted in accordance with Method 21 of 
appendix A of this part.
    (2)(i) Except as provided in paragraph (b)(2)(ii) of this section, 
the detection instrument must meet the performance criteria of Method 
21 of appendix A of this part, except the instrument response factor 
criteria in section 3.1.2(a) of Method 21 must be for the average 
composition of the process fluid not each individual volatile organic 
compound in the stream. For process streams that contain nitrogen, air, 
or other inerts which are not organic hazardous air pollutants or 
volatile organic compounds, the average stream response factor must be 
calculated on an inert-free basis.
    (ii) If no instrument is available at the plant site that will meet 
the performance criteria specified in paragraph (b)(2)(i) of this 
section, the instrument readings may be adjusted by multiplying by the 
average response factor of the process fluid, calculated on an inert-
free basis as described in paragraph (b)(2)(i).
    (3) The detection instrument must be calibrated before use on each 
day of its use by the procedures specified in Method 21 of appendix A 
of this part.
    (4) Calibration gases must be as follows:
    (i) Zero air (less than 10 parts per million hydrocarbon in air); 
and
    (ii) Mixtures of methane in air at a concentration less than 2,000 
parts per million. A calibration gas other than methane in air may be 
used if the instrument does not respond to methane or if the instrument 
does not meet the performance criteria specified in paragraph (b)(2)(i) 
of this section. In such cases, the calibration gas may be a mixture of 
one or more of the compounds to be measured in air.
    (5) You may elect to adjust or not adjust instrument readings for 
background. If you elect to not adjust readings for background, all 
such instrument readings must be compared directly to the applicable 
leak definition to determine whether there is a leak.
    (6) If you elect to adjust instrument readings for background, you 
must determine the background concentration using Method 21 of appendix 
A of this part. After monitoring each potential leak interface, 
subtract the background reading from the maximum concentration 
indicated by the instrument. The arithmetic difference between the 
maximum concentration indicated by the instrument and the background 
level must be compared with 500 parts per million for determining 
compliance.
    (c) Leaks, as indicated by an instrument reading greater than 500 
parts per million above background or by visual, audio, or olfactory 
inspections, must be repaired as soon as practicable, except as 
provided in paragraph (d) of this section.
    (1) A first attempt at repair must be made no later than 5 calendar 
days after the leak is detected.
    (2) Repair must be completed no later than 15 calendar days after 
the leak is detected.
    (d) Delay of repair of a closed vent system for which leaks have 
been detected is allowed if the repair is technically infeasible 
without a shutdown, as defined in Sec.  60.2, or if you determine that 
emissions resulting from immediate repair would be greater than the 
fugitive emissions likely to result from delay of repair. Repair of 
such equipment must be complete by the end of the next shutdown.
    (e) For each closed vent system that contains bypass lines that 
could divert a vent stream away from the control device and to the 
atmosphere, you must comply with the provisions of either paragraph 
(e)(1) or (2), except as specified in paragraph (e)(3) of this section.
    (1) Install, calibrate, maintain, and operate a flow indicator that 
determines whether vent stream flow is present at least once every 15 
minutes. You must keep hourly records of whether the flow indicator was 
operating and whether a diversion was detected at any time during the 
hour, as well as records of the times and durations of all periods when 
the vent stream is diverted to the atmosphere or the flow indicator is 
not operating. The flow indicator must be installed at the entrance to 
any bypass line; or
    (2) Secure the bypass line valve in the closed position with a car-
seal or a lock-and-key type configuration. A visual inspection of the 
seal or closure mechanism must be performed at least once every month 
to ensure the valve is maintained in the closed position and the vent 
stream is not diverted through the bypass line.
    (3) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in Sec.  60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as Sec.  60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (e) of this section.
    (f) Any parts of the closed vent system that are designated, as 
described in paragraph (h)(1) of this section, as unsafe to inspect are 
exempt from the inspection requirements of paragraphs (a)(1) and (2) of 
this section if:
    (1) You determine that the equipment is unsafe to inspect because 
inspecting personnel would be exposed to an imminent or potential 
danger as a consequence of complying with paragraphs (a)(1) and (2) of 
this section; and
    (2) You have a written plan that requires inspection of the 
equipment as frequently as practicable during safe-to-inspect times.
    (g) Any parts of the closed vent system are designated, as 
described in paragraph (h)(2) of this section, as difficult to inspect 
are exempt from the inspection requirements of paragraphs (a)(1) and 
(2) of this section if:
    (1) You determine that the equipment cannot be inspected without 
elevating the inspecting personnel more than 2 meters above a support 
surface; and
    (2) You have a written plan that requires inspection of the 
equipment at least once every 5 years.
    (h) You must record the information specified in paragraphs (h)(1) 
through (5) of this section.
    (1) Identification of all parts of the closed vent system that are 
designated as unsafe to inspect, an explanation of why the equipment is 
unsafe to inspect, and the plan for inspecting the equipment.
    (2) Identification of all parts of the closed vent system that are 
designated as difficult to inspect, an explanation of why the equipment 
is difficult to inspect, and the plan for inspecting the equipment.
    (3) For each closed vent system that contains bypass lines that 
could divert a vent stream away from the control device and to the 
atmosphere, you must keep a record of the information specified in 
either paragraph (h)(3)(i) or (ii) of this section in addition to the

[[Page 43125]]

information specified in paragraph (h)(3)(iii) of this section.
    (i) Hourly records of whether the flow indicator specified under 
paragraph (e)(1) of this section was operating and whether a diversion 
was detected at any time during the hour, as well as records of the 
times of all periods when the vent stream is diverted from the control 
device or the flow indicator is not operating.
    (ii) Where a seal mechanism is used to comply with paragraph (e)(2) 
of this section, hourly records of flow are not required. In such 
cases, you must record whether the monthly visual inspection of the 
seals or closure mechanisms has been done, and you must record the 
occurrence of all periods when the seal mechanism is broken, the bypass 
line valve position has changed, or the key for a lock-and-key type 
configuration has been checked out, and records of any car-seal that 
has broken.
    (iii) For each flow event from a bypass line subject to the 
requirements in paragraph (e) of this section, you must maintain 
records sufficient to determine whether or not the detected flow 
included flow requiring control. For each flow event from a bypass line 
requiring control that is released either directly to the atmosphere or 
to a control device not meeting the requirements in this subpart, you 
must include an estimate of the volume of gas, the concentration of VOC 
in the gas and the resulting emissions of VOC that bypassed the control 
device using process knowledge and engineering estimates.
    (4) For each inspection during which a leak is detected, a record 
of the information specified in paragraphs (h)(4)(i) through (viii) of 
this section.
    (i) The instrument identification numbers; operator name or 
initials; and identification of the equipment.
    (ii) The date the leak was detected and the date of the first 
attempt to repair the leak.
    (iii) Maximum instrument reading measured by the method specified 
in paragraph (c) of this section after the leak is successfully 
repaired or determined to be nonrepairable.
    (iv) ``Repair delayed'' and the reason for the delay if a leak is 
not repaired within 15 calendar days after discovery of the leak.
    (v) The name, initials, or other form of identification of the 
owner or operator (or designee) whose decision it was that repair could 
not be effected without a shutdown.
    (vi) The expected date of successful repair of the leak if a leak 
is not repaired within 15 calendar days.
    (vii) Dates of shutdowns that occur while the equipment is 
unrepaired.
    (viii) The date of successful repair of the leak.
    (5) For each inspection conducted in accordance with paragraph (b) 
of this section during which no leaks are detected, a record that the 
inspection was performed, the date of the inspection, and a statement 
that no leaks were detected.
    (6) For each inspection conducted in accordance with paragraph 
(a)(3) of this section during which no leaks are detected, a record 
that the inspection was performed, the date of the inspection, and a 
statement that no leaks were detected.
    (i) The semiannual report specified in Sec.  60.665a(j)(5) must 
include the items specified in paragraphs (i)(1) through (3) of this 
section.
    (1) Reports of the times of all periods recorded under paragraph 
(h)(3)(i) of this section when the vent stream is diverted from the 
control device through a bypass line. Include the start date, start 
time, and duration in hours of each period.
    (2) Reports of all periods recorded under paragraph (h)(3)(ii) of 
this section in which the seal mechanism is broken, the bypass line 
valve position has changed, or the key to unlock the bypass line valve 
was checked out. Include the start date, start time, and duration in 
hours of each period.
    (3) For bypass lines subject to the requirements in paragraph (e) 
of this section, the semiannual reports must include the start date, 
start time, duration in hours, estimate of the volume of gas in 
standard cubic feet, the concentration of VOC in the gas in parts per 
million by volume and the resulting mass emissions of VOC in pounds 
that bypass a control device. For periods when the flow indicator is 
not operating, report the start date, start time, and duration in 
hours.

  Table 1 to Subpart NNNa of Part 60--Emission Limits and Standards for
                              Vent Streams
------------------------------------------------------------------------
          For each . . .                       You must . . .
------------------------------------------------------------------------
1. Vent stream....................  a. Reduce emissions of TOC (minus
                                     methane and ethane) by 98 weight-
                                     percent, or to a TOC (minus methane
                                     and ethane) concentration of 20
                                     ppmv on a dry basis corrected to 3
                                     percent oxygen by venting emissions
                                     through a closed vent system to any
                                     combination of non-flare control
                                     devices and/or recovery system and
                                     meet the requirements specified in
                                     Sec.   60.663a and Sec.   60.670a;
                                     or
                                    b. Reduce emissions of TOC (minus
                                     methane and ethane) by venting
                                     emissions through a closed vent
                                     system to a flare and meet the
                                     requirements specified in Sec.
                                     60.669a and Sec.   60.670a.
------------------------------------------------------------------------


     Table 2 to Subpart NNNa of Part 60--Monitoring Requirements for
  Complying With 98 Weight-Percent Reduction of Total Organic Compounds
         Emissions or a Limit of 20 Parts per Million by Volume
------------------------------------------------------------------------
   Non-flare control device or
         recovery device                 Parameters to be monitored
------------------------------------------------------------------------
1. All control and recovery        a. Presence of flow diverted to the
 devices.                           atmosphere from the control and
                                    recovery device; or
                                   b. Monthly inspections of sealed
                                    valves
2. Absorber......................  a. Exit temperature of the absorbing
                                    liquid; and
                                   b. Exit specific gravity
3. Boiler or process heater with   Firebox temperature \a\
 a design heat input capacity
 less than 44 megawatts and vent
 stream is not introduced with or
 as the primary fuel.
4. Catalytic incinerator.........  Temperature upstream and downstream
                                    of the catalyst bed
5. Carbon adsorber, regenerative.  a. Total regeneration stream mass or
                                    volumetric flow during carbon bed
                                    regeneration cycle(s); and
                                   b. Temperature of the carbon bed
                                    after regeneration [and within 15
                                    minutes of completing any cooling
                                    cycle(s)]

[[Page 43126]]

 
6. Carbon adsorber, non-           Breakthrough
 regenerative or regenerated
 offsite.
7. Condenser.....................  Exit (product side) temperature
8. Scrubber for halogenated vent   a. pH of scrubber effluent; and
 streams.
                                   b. Scrubber liquid and gas flow rates
9. Thermal incinerator...........  Firebox temperature \a\
10. Control devices other than an  As specified by the Administrator
 incinerator, boiler, process
 heater, or flare; or recovery
 devices other than an absorber,
 condenser, or carbon adsorber.
------------------------------------------------------------------------
\a\ Monitor may be installed in the firebox or in the ductwork
  immediately downstream of the firebox before any substantial heat
  exchange is encountered.


    Table 3 to Subpart NNNa of Part 60--Operating Parameters, Operating Parameter Limits and Data Monitoring,
                                    Recordkeeping and Compliance Frequencies
----------------------------------------------------------------------------------------------------------------
                                      You must        And you must monitor, record, and demonstrate continuous
                                   establish the          compliance using these minimum frequencies . . .
  For the  operating parameter       following     -------------------------------------------------------------
     applicable to you, as           operating                                                  Data  averaging
      specified in table 2       parameter limit .     Data measurement       Data recording       period for
                                        . .                                                        compliance
----------------------------------------------------------------------------------------------------------------
                                                    Absorbers
----------------------------------------------------------------------------------------------------------------
1. Exit temperature of the       Maximum            Continuous............  Every 15 minutes.  3-hour block
 absorbing liquid.                temperature.                                                  average.
2. Exit specific gravity.......  Exit specific      Continuous............  Every 15 minutes.  3-hour block
                                  gravity range.                                                average.
----------------------------------------------------------------------------------------------------------------
                                           Boilers or process heaters
     (with a design heat input capacity <44MW and vent stream is not introduced with or as the primary fuel)
----------------------------------------------------------------------------------------------------------------
3. Firebox temperature.........  Minimum firebox    Continuous............  Every 15 minutes.  3-hour block
                                  temperature.                                                  average.
----------------------------------------------------------------------------------------------------------------
                                             Catalytic incinerators
----------------------------------------------------------------------------------------------------------------
4. Temperature in gas stream     Minimum            Continuous............  Every 15 minutes.  3-hour block
 immediately before the           temperature.                                                  average.
 catalyst bed.
5. Temperature difference        Minimum            Continuous............  Every 15 minutes.  3-hour block
 between the catalyst bed inlet   temperature                                                   average.
 and the catalyst bed outlet.     difference.
----------------------------------------------------------------------------------------------------------------
                                                Carbon adsorbers
----------------------------------------------------------------------------------------------------------------
6. Total regeneration stream     Minimum mass flow  Continuously during     Every 15 minutes   Total flow for
 mass flow during carbon bed      during carbon      regeneration.           during             each
 regeneration cycle(s).           bed regeneration                           regeneration       regeneration
                                  cycle(s).                                  cycle.             cycle.
7. Total regeneration stream     Minimum            Continuously during     Every 15 minutes   Total flow for
 volumetric flow during carbon    volumetric flow    regeneration.           during             each
 bed regeneration cycle(s).       during carbon                              regeneration       regeneration
                                  bed regeneration                           cycle.             cycle.
                                  cycle(s).
8. Temperature of the carbon     Maximum            Continuously during     Every 15 minutes   Average of
 bed after regeneration [and      temperature of     regeneration and for    during             regeneration
 within 15 minutes of             the carbon bed     15 minutes after        regeneration       cycle.
 completing any cooling           after              completing any          cycle (including
 cycle(s)].                       regeneration.      cooling cycle(s).       any cooling
                                                                             cycle).
9. Breakthrough................  As defined in      As required by Sec.     Each monitoring    N/A.
                                  Sec.   60.661a.    60.663a(a)(6)(iii)(B).  event.
----------------------------------------------------------------------------------------------------------------

[[Page 43127]]

 
                                                   Condensers
----------------------------------------------------------------------------------------------------------------
10. Exit (product side)          Maximum            Continuous............  Every 15 minutes.  3-hour block
 temperature.                     temperature.                                                  average.
----------------------------------------------------------------------------------------------------------------
                                     Scrubbers for halogenated vent streams
----------------------------------------------------------------------------------------------------------------
11. pH of scrubber effluent....  Minimum pH.......  Continuous............  Every 15 minutes.  3-hour block
                                                                                                average.
12. Influent liquid flow.......  Minimum inlet      Continuous............  Every 15 minutes.  3-hour block
                                  liquid flow.                                                  average.
13. Influent liquid flow rate    Minimum influent   Continuous............  Every 15 minutes.  3-hour block
 and gas stream flow rate.        liquid-to-gas                                                 average.
                                  ratio.
----------------------------------------------------------------------------------------------------------------
                                              Thermal incinerators
----------------------------------------------------------------------------------------------------------------
14. Firebox temperature........  Minimum firebox    Continuous............  Every 15 minutes.  3-hour block
                                  temperature.                                                  average.
----------------------------------------------------------------------------------------------------------------
 Control devices other than an incinerator, boiler, process heater, or flare; or recovery devices other than an
                                     absorber, condenser, or carbon adsorber
----------------------------------------------------------------------------------------------------------------
15. As specified by the          15. As specified   15. As specified by     15. As specified   15. As specified
 Administrator.                   by the             the Administrator.      by the             by the
                                  Administrator.                             Administrator.     Administrator.
----------------------------------------------------------------------------------------------------------------


   Table 4 to Subpart NNNa of Part 60--Calibration and Quality Control
     Requirements for Continuous Parameter Monitoring System (CPMS)
------------------------------------------------------------------------
                                                    And your calibration
     If you monitor this          Your accuracy     requirements are . .
       parameter . . .        requirements are . .            .
                                        .
------------------------------------------------------------------------
1. Temperature..............  a.  1     c. Performance
                               percent over the      evaluation annually
                               normal range of       and following any
                               temperature           period of more than
                               measured or 2.8       24 hours throughout
                               degrees Celsius (5    which the
                               degrees               temperature
                               Fahrenheit),          exceeded the
                               whichever is          maximum rated
                               greater, for non-     temperature of the
                               cryogenic             sensor, or the data
                               temperature ranges.   recorder was off
                              b.  2.5    scale.
                               percent over the     d. Visual
                               normal range of       inspections and
                               temperature           checks of CPMS
                               measured or 2.8       operation every 3
                               degrees Celsius (5    months, unless the
                               degrees               CPMS has a
                               Fahrenheit),          redundant
                               whichever is          temperature sensor.
                               greater, for         e. Selection of a
                               cryogenic             representative
                               temperature ranges.   measurement
                                                     location.
2. Flow Rate................  a.  5     d. Performance
                               percent over the      evaluation annually
                               normal range of       and following any
                               flow measured or      period of more than
                               1.9 liters per        24 hours throughout
                               minute (0.5 gallons   which the flow rate
                               per minute),          exceeded the
                               whichever is          maximum rated flow
                               greater, for liquid   rate of the sensor,
                               flow rate.            or the data
                              b.  5      recorder was off
                               percent over the      scale.
                               normal range of      e. Checks of all
                               flow measured or      mechanical
                               280 liters per        connections for
                               minute (10 cubic      leakage monthly.
                               feet per minute),    f. Visual
                               whichever is          inspections and
                               greater, for gas      checks of CPMS
                               flow rate.            operation every 3
                              c.  5      months, unless the
                               percent over the      CPMS has a
                               normal range          redundant flow
                               measured for mass     sensor.
                               flow rate.           g. Selection of a
                                                     representative
                                                     measurement
                                                     location where
                                                     swirling flow or
                                                     abnormal velocity
                                                     distributions due
                                                     to upstream and
                                                     downstream
                                                     disturbances at the
                                                     point of
                                                     measurement are
                                                     minimized.
3. pH.......................  a.  0.2   b. Performance
                               pH units.             evaluation
                                                     annually. Conduct a
                                                     two-point
                                                     calibration with
                                                     one of the two
                                                     buffer solutions
                                                     having a pH within
                                                     1 of the pH of the
                                                     operating limit.
                                                    c. Visual
                                                     inspections and
                                                     checks of CPMS
                                                     operation every 3
                                                     months, unless the
                                                     CPMS has a
                                                     redundant pH
                                                     sensor.
                                                    d. Select a
                                                     measurement
                                                     location that
                                                     provides a
                                                     representative
                                                     sample of scrubber
                                                     effluent and that
                                                     ensures the fluid
                                                     is properly mixed.

[[Page 43128]]

 
4. Specific Gravity.........  a.  0.02  b. Performance
                               specific gravity      evaluation
                               units.                annually.
                                                    c. Visual
                                                     inspections and
                                                     checks of CPMS
                                                     operation every 3
                                                     months, unless the
                                                     CPMS has a
                                                     redundant specific
                                                     gravity sensor.
                                                    d. Select a
                                                     measurement
                                                     location that
                                                     provides a
                                                     representative
                                                     sample of specific
                                                     gravity of the
                                                     absorbing liquid
                                                     effluent and that
                                                     ensures the fluid
                                                     is properly mixed.
------------------------------------------------------------------------


0
33. Revise the heading for subpart RRR to read as follows:

Subpart RRR--Standards of Performance for Volatile Organic Compound 
Emissions From Synthetic Organic Chemical Manufacturing Industry 
(SOCMI) Reactor Processes After June 29, 1990, and on or Before 
April 25, 2023

0
34. Amend Sec.  60.700 by revising paragraphs (b) introductory text and 
(c)(5) and (8) and adding paragraph (e) to read as follows:


Sec.  60.700  Applicability and designation of affected facility.

* * * * *
    (b) The affected facility is any of the following for which 
construction, modification, or reconstruction commenced after June 29, 
1990, and on or before April 25, 2023:
    (c) * * *
    (5) If the vent stream from an affected facility is routed to a 
distillation unit subject to subpart NNN of this part or subpart NNNa 
of this part, and has no other releases to the air except for a 
pressure relief valve, the facility is exempt from all provisions of 
this subpart except for Sec.  60.705(r).
* * * * *
    (8) Each affected facility operated with a concentration of total 
organic compounds (TOC) (less methane and ethane) in the vent stream 
less than 300 ppmv as measured by Method 18 of appendix A-6 to this 
part or ASTM D6420-18 (incorporated by reference, see Sec.  60.17) as 
specified in Sec.  60.704(b)(4), or a concentration of TOC in the vent 
stream less than 150 ppmv as measured by Method 25A of appendix A-7 to 
this part is exempt from all provisions of this subpart except for the 
test method and procedure and the reporting and recordkeeping 
requirements in Sec. Sec.  60.704(h) and 60.705(j), (l)(8), and (p).
* * * * *
    (e) Owners and operators of flares that are subject to the flare 
related requirements of this subpart and flare related requirements of 
any other regulation in this part or 40 CFR part 61 or 63, may elect to 
comply with the requirements in Sec.  60.709a in lieu of all flare 
related requirements in any other regulation in this part or 40 CFR 
part 61 or 63.

0
35. Amend Sec.  60.701 by revising the definition of ``Flame zone'' as 
follows to read as follows:


Sec.  60.701  Definitions.

* * * * *
    Flame zone means the portion of the combustion chamber in a boiler 
or process heater occupied by the flame envelope.
* * * * *

0
36. Amend Sec.  60.704 by revising paragraphs (b)(3), (b)(4) 
introductory text, (d), and (h)(2) and (3) to read as follows:


Sec.  60.704  Test methods and procedures.

* * * * *
    (b) * * *
    (3) The emission rate correction factor, integrated sampling and 
analysis procedures of Method 3B of appendix A-2 to this part, or the 
manual method in ANSI/ASME PTC 19.10-1981 incorporated by reference, 
see Sec.  60.17), shall be used to determine the oxygen concentration 
(%O2d) for the purposes of determining compliance with the 20 ppmv 
limit. The sampling site shall be the same as that of the TOC samples, 
and the samples shall be taken during the same time that the TOC 
samples are taken. The TOC concentration corrected to 3 percent O2 (Cc) 
shall be computed using the following equation:
[GRAPHIC] [TIFF OMITTED] TR16MY24.044

Where:

Cc = Concentration of TOC corrected to 3 percent 
O2, dry basis, ppm by volume.
CTOC = Concentration of TOC (minus methane and ethane), 
dry basis, ppm by volume.
%O2d = Concentration of O2, dry basis, percent 
by volume.

    (4) Method 18 of appendix A-6 to this part to determine the 
concentration of TOC in the control device outlet and the concentration 
of TOC in the inlet when the reduction efficiency of the control device 
is to be determined. ASTM D6420-18 (incorporated by reference, see 
Sec.  60.17) may be used in lieu of Method 18 of appendix A-6 to this 
part, if the target compounds are all known and are all listed in 
Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 may not be 
used for methane and ethane; and ASTM D6420-18 may not be used as a 
total VOC method.
* * * * *
    (d) The following test methods, except as provided under Sec.  
60.8(b), shall be used for determining the net heating value of the gas 
combusted to determine compliance under Sec.  60.702(b) and for 
determining the process vent stream TRE index value to determine 
compliance under Sec. Sec.  60.700(c)(2) and 60.702(c).
    (1)(i) Method 1 or 1A of appendix A-1 to this part, as appropriate, 
for selection of the sampling site. The sampling site for the vent 
stream flow rate and molar composition determination prescribed in 
Sec.  60.704(d)(2) and (3) shall be, except

[[Page 43129]]

for the situations outlined in paragraph (d)(1)(ii) of this section, 
prior to the inlet of any control device, prior to any postreactor 
dilution of the stream with air, and prior to any postreactor 
introduction of halogenated compounds into the process vent stream. No 
traverse site selection method is needed for vents smaller than 4 
inches in diameter.
    (ii) If any gas stream other than the reactor vent stream is 
normally conducted through the final recovery device:
    (A) The sampling site for vent stream flow rate and molar 
composition shall be prior to the final recovery device and prior to 
the point at which any nonreactor stream or stream from a nonaffected 
reactor process is introduced.
    (B) The efficiency of the final recovery device is determined by 
measuring the TOC concentration using Method 18 of appendix A-6 to this 
part, or ASTM D6420-18 (incorporated by reference, see Sec.  60.17) as 
specified in paragraph (b)(4) of this section, at the inlet to the 
final recovery device after the introduction of any vent stream and at 
the outlet of the final recovery device.
    (C) This efficiency of the final recovery device shall be applied 
to the TOC concentration measured prior to the final recovery device 
and prior to the introduction of any nonreactor stream or stream from a 
nonaffected reactor process to determine the concentration of TOC in 
the reactor process vent stream from the final recovery device. This 
concentration of TOC is then used to perform the calculations outlined 
in paragraphs (d)(4) and (5) of this section.
    (2) The molar composition of the process vent stream shall be 
determined as follows:
    (i) Method 18 of appendix A-6 to this part, or ASTM D6420-18 
(incorporated by reference, see Sec.  60.17) as specified in paragraph 
(b)(4) of this section, to measure the concentration of TOC including 
those containing halogens.
    (ii) ASTM D1946-77 or 90 (Reapproved 1994) (incorporation by 
reference as specified in Sec.  60.17 of this part) to measure the 
concentration of carbon monoxide and hydrogen.
    (iii) Method 4 of appendix A-3 to this part to measure the content 
of water vapor.
    (3) The volumetric flow rate shall be determined using Method 2, 
2A, 2C, or 2D of appendix A-1 to this part, as appropriate.
    (4) The net heating value of the vent stream shall be calculated 
using the following equation:
[GRAPHIC] [TIFF OMITTED] TR16MY24.045

Where:

HT = Net heating value of the sample, MJ/scm, where the 
net enthalpy per mole of vent stream is based on combustion at 25 
[deg]C and 760 mm Hg, but the standard temperature for determining 
the volume corresponding to one mole is 20 [deg]C, as in the 
definition of Qs (vent stream flow rate).
K1 = Constant, 1.740 x 10-7 (l/ppm) (g-mole/
scm) (MJ/kcal), where standard temperature for (g-mole/scm) is 20 
[deg]C.
Cj = Concentration on a dry basis of compound j in ppm, 
as measured for organics by Method 18 of appendix A-6 to this part, 
or ASTM D6420-18 (incorporated by reference, see Sec.  60.17) as 
specified in paragraph (b)(4) of this section, and measured for 
hydrogen and carbon monoxide by ASTM D1946-77 or 90 (Reapproved 
1994) (incorporated by reference, see Sec.  60.17) as indicated in 
paragraph (d)(2) of this section.
Hj = Net heat of combustion of compound j, kcal/g-mole, 
based on combustion at 25 [deg]C and 760 mm Hg. The heats of 
combustion of vent stream components would be required to be 
determined using ASTM D2382-76 or 88 or D4809-95 (incorporated by 
reference, see Sec.  60.17) if published values are not available or 
cannot be calculated.
Bws = Water vapor content of the vent stream, proportion 
by volume.

    (5) The emission rate of TOC in the vent stream shall be calculated 
using the following equation:
[GRAPHIC] [TIFF OMITTED] TR16MY24.046

Where:

ETOC = Emission rate of TOC in the sample, kg/hr.
K2 = Constant, 2.494 x 10-6 (l/ppm) (g-mole/
scm) (kg/g) (min/hr), where standard temperature for (g-mole/scm) is 
20 [deg]C.
Cj = Concentration on a dry basis of compound j in ppm as 
measured by Method 18 of appendix A-6 to this part, or ASTM D6420-18 
(incorporated by reference, see Sec.  60.17) as specified in 
paragraph (b)(4) of this section, as indicated in paragraph (d)(2) 
of this section.
Mj = Molecular weight of sample j, g/g-mole.
Qs = Vent stream flow rate (dscm/min) at a temperature of 
20 [deg]C.

    (6) The total vent stream concentration (by volume) of compounds 
containing halogens (ppmv, by compound) shall be summed from the 
individual concentrations of compounds containing halogens which were 
measured by Method 18 of appendix A-6 to this part, or ASTM D6420-18 
(incorporated by reference, see Sec.  60.17) as specified in paragraph 
(b)(4) of this section.
* * * * *
    (h) * * *
    (2) Method 18 of appendix A-6 or Method 25A of appendix A-7 to this 
part shall be used to measure concentration. ASTM D6420-18 
(incorporated by reference, see Sec.  60.17) may be used in lieu of 
Method 18 as specified in paragraph (b)(4) of this section.
    (3) Where Method 18 of appendix A-6 to this part, or ASTM D6420-18 
(incorporated by reference, see Sec.  60.17) as specified in paragraph 
(b)(4) of this section, is used to qualify for the low concentration 
exclusion in Sec.  60.700(c)(8), the procedures in paragraphs (b)(4)(i) 
and (iv) of this section shall be used to measure TOC concentration, 
and the procedures of paragraph (b)(3) of this section shall be used to 
correct the TOC concentration to 3 percent oxygen. To qualify for the 
exclusion, the results must demonstrate that the concentration of TOC, 
corrected to 3 percent oxygen, is below 300 ppm by volume.
* * * * *

0
37. Amend Sec.  60.705 by revising paragraphs (b) introductory text, 
(l), and (m) and adding paragraphs (u), (v), and (w) to read as 
follows:

[[Page 43130]]

Sec.  60.705  Reporting and recordkeeping requirements.

* * * * *
    (b) Each owner or operator subject to the provisions of this 
subpart shall keep an up-to-date, readily accessible record of the 
following data measured during each performance test, and also include 
the following data in the report of the initial performance test 
required under Sec.  60.8. Where a boiler or process heater with a 
design heat input capacity of 44 MW (150 million Btu/hour) or greater 
is used or where the reactor process vent stream is introduced as the 
primary fuel to any size boiler or process heater to comply with Sec.  
60.702(a), a report containing performance test data need not be 
submitted, but a report containing the information in paragraph 
(b)(2)(i) of this section is required. The same data specified in this 
section shall be submitted in the reports of all subsequently required 
performance tests where either the emission control efficiency of a 
combustion device, outlet concentration of TOC, or the TRE index value 
of a vent stream from a recovery system is determined. Beginning on 
July 15, 2024, owners and operators must submit the performance test 
report following the procedures specified in paragraph (u) of this 
section. Data collected using test methods that are supported by the 
EPA's Electronic Reporting Tool (ERT) as listed on the EPA's ERT 
website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test must be 
submitted in a file format generated using the EPA's ERT. 
Alternatively, the owner or operator may submit an electronic file 
consistent with the extensible markup language (XML) schema listed on 
the EPA's ERT website. Data collected using test methods that are not 
supported by the EPA's ERT as listed on the EPA's ERT website at the 
time of the test must be included as an attachment in the ERT or an 
alternate electronic file.
* * * * *
    (l) Each owner or operator that seeks to comply with the 
requirements of this subpart by complying with the requirements of 
Sec.  60.700(c)(2), (3), or (4) or Sec.  60.702 shall submit to the 
Administrator semiannual reports of the following recorded information. 
The initial report shall be submitted within 6 months after the initial 
start-up date. On and after July 15, 2025 or once the report template 
for this subpart has been available on the Compliance and Emissions 
Data Reporting Interface (CEDRI) website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 year, whichever date is 
later, owners and operators must submit all subsequent reports using 
the appropriate electronic report template on the CEDRI website for 
this subpart and following the procedure specified in paragraph (u) of 
this section. The date report templates become available will be listed 
on the CEDRI website. Unless the Administrator or delegated state 
agency or other authority has approved a different schedule for 
submission of reports, the report must be submitted by the deadline 
specified in this subpart, regardless of the method in which the report 
is submitted.
    (1) Exceedances of monitored parameters recorded under paragraphs 
(c), (f), and (g) of this section.
    (2) All periods and duration recorded under paragraph (d) of this 
section when the vent stream is diverted from the control device to the 
atmosphere.
    (3) All periods recorded under paragraph (e) of this section in 
which the pilot flame of the flare was absent.
    (4) Any change in equipment or process operation that increases the 
operating vent stream flow rate above the low flow exemption level in 
Sec.  60.700(c)(4), including a measurement of the new vent stream flow 
rate, as recorded under paragraph (i) of this section. These must be 
reported as soon as possible after the change and no later than 180 
days after the change. These reports may be submitted either in 
conjunction with semiannual reports or as a single separate report. A 
performance test must be completed within the same time period to 
verify the recalculated flow value and to obtain the vent stream 
characteristics of heating value and ETOC. The performance 
test is subject to the requirements of Sec.  60.8, and the performance 
test must be reported according to paragraph (b) of this section. 
Unless the facility qualifies for an exemption under any of the 
exemption provisions listed in Sec.  60.700(c), except for the total 
resource effectiveness index greater than 8.0 exemption in Sec.  
60.700(c)(2), the facility must begin compliance with the requirements 
set forth in Sec.  60.702.
    (5) Any change in equipment or process operation, as recorded under 
paragraph (i) of this section, that increases the design production 
capacity above the low capacity exemption level in Sec.  60.700(c)(3) 
and the new capacity resulting from the change for the reactor process 
unit containing the affected facility. These must be reported as soon 
as possible after the change and no later than 180 days after the 
change. These reports may be submitted either in conjunction with 
semiannual reports or as a single separate report. A performance test 
must be completed within the same time period to obtain the vent stream 
flow rate, heating value, and ETOC. The performance test is 
subject to the requirements of Sec.  60.8, and the performance test 
must be reported according to paragraph (b) of this section. The 
facility must begin compliance with the requirements set forth in Sec.  
60.702 or Sec.  60.700(d). If the facility chooses to comply with Sec.  
60.702, the facility may qualify for an exemption under Sec.  
60.700(c)(2), (4), or (8).
    (6) Any recalculation of the TRE index value, as recorded under 
paragraph (g) of this section.
    (7) All periods recorded under paragraph (d) of this section in 
which the seal mechanism is broken or the by-pass line valve position 
has changed. A record of the serial number of the car-seal or a record 
to show that the key to unlock the bypass line valve was checked out 
must be maintained to demonstrate the period, the duration, and 
frequency in which the bypass line was operated.
    (8) Any change in equipment or process operation that increases the 
vent stream concentration above the low concentration exemption level 
in Sec.  60.700(c)(8), including a measurement of the new vent stream 
concentration, as recorded under paragraph (j) of this section. These 
must be reported as soon as possible after the change and no later than 
180 days after the change. These reports may be submitted either in 
conjunction with semiannual reports or as a single separate report. If 
the vent stream concentration is above 300 ppmv as measured using 
Method 18 of appendix A-6 to this part, or ASTM D6420-18 (incorporated 
by reference, see Sec.  60.17) as specified in Sec.  60.704(b)(4), or 
above 150 ppmv as measured using Method 25A of appendix A-7 to this 
part, a performance test must be completed within the same time period 
to obtain the vent stream flow rate, heating value, and ETOC. The 
performance test is subject to the requirements of Sec.  60.8, and the 
performance test must be reported according to paragraph (b) of this 
section. Unless the facility qualifies for an exemption under any of 
the exemption provisions listed in Sec.  60.700(c), except for the TRE 
index greater than 8.0 exemption in Sec.  60.700(c)(2), the facility 
must begin compliance with the requirements set forth in Sec.  60.702.
    (m) The requirements of paragraph (l) of this section remain in 
force until and unless EPA, in delegating enforcement authority to a 
State under section 111(c)

[[Page 43131]]

of the Act, approves reporting requirements or an alternative means of 
compliance surveillance adopted by such State. In that event, affected 
sources within the State will be relieved of the obligation to comply 
with paragraph (l), provided that they comply with the requirements 
established by the State. The EPA will not approve a waiver of 
electronic reporting to the EPA in delegating enforcement authority. 
Thus, electronic reporting to the EPA cannot be waived, and as such, 
the provisions of this paragraph cannot be used to relieve owners or 
operators of affected facilities of the requirement to submit the 
electronic reports required in this section to the EPA.
* * * * *
    (u) If an owner or operator is required to submit notifications or 
reports following the procedure specified in this paragraph (u), the 
owner or operator must submit notifications or reports to the EPA via 
CEDRI, which can be accessed through the EPA's Central Data Exchange 
(CDX) (https://cdx.epa.gov/). The EPA will make all the information 
submitted through CEDRI available to the public without further notice 
to the owner or operator. Do not use CEDRI to submit information the 
owner or operator claims as CBI. Although the EPA does not expect 
persons to assert a claim of CBI, if an owner or operator wishes to 
assert a CBI claim for some of the information in the report or 
notification, the owner or operator must submit a complete file in the 
format specified in this subpart, including information claimed to be 
CBI, to the EPA following the procedures in paragraphs (u)(1) and (2) 
of this section. Clearly mark the part or all of the information 
claimed to be CBI. Information not marked as CBI may be authorized for 
public release without prior notice. Information marked as CBI will not 
be disclosed except in accordance with procedures set forth in 40 CFR 
part 2. All CBI claims must be asserted at the time of submission. 
Anything submitted using CEDRI cannot later be claimed CBI. 
Furthermore, under CAA section 114(c), emissions data is not entitled 
to confidential treatment, and the EPA is required to make emissions 
data available to the public. Thus, emissions data will not be 
protected as CBI and will be made publicly available. The owner or 
operator must submit the same file submitted to the CBI office with the 
CBI omitted to the EPA via the EPA's CDX as described earlier in this 
paragraph (u).
    (1) The preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
[email protected], and as described above, should include clear CBI 
markings. ERT files should be flagged to the attention of the Group 
Leader, Measurement Policy Group; all other files should be flagged to 
the attention of the SOCMI NSPS Sector Lead. Owners and operators who 
do not have their own file sharing service and who require assistance 
with submitting large electronic files that exceed the file size limit 
for email attachments should email [email protected] to request a file 
transfer link.
    (2) If an owner or operator cannot transmit the file 
electronically, the owner or operator may send CBI information through 
the postal service to the following address: OAQPS Document Control 
Officer (C404-02), OAQPS, U.S. Environmental Protection Agency, 109 
T.W. Alexander Drive, P.O. Box 12055, Research Triangle Park, North 
Carolina 27711. ERT files should be sent to the attention of the Group 
Leader, Measurement Policy Group, and all other files should be sent to 
the attention of the SOCMI NSPS Sector Lead. The mailed CBI material 
should be double wrapped and clearly marked. Any CBI markings should 
not show through the outer envelope.
    (v) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX may assert a 
claim of EPA system outage for failure to timely comply with the 
electronic submittal requirement. To assert a claim of EPA system 
outage, owners and operators must meet the requirements outlined in 
paragraphs (v)(1) through (7) of this section.
    (1) The owner or operator must have been or will be precluded from 
accessing CEDRI and submitting a required report within the time 
prescribed due to an outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (5) The owner or operator must provide to the Administrator a 
written description identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which the owner or operator proposes to report, or 
if the owner or operator has already met the reporting requirement at 
the time of the notification, the date the report was submitted.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (w) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX may assert a 
claim of force majeure for failure to timely comply with the electronic 
submittal requirement. To assert a claim of force majeure, owners and 
operators must meet the requirements outlined in paragraphs (w)(1) 
through (5) of this section.
    (1) An owner or operator may submit a claim if a force majeure 
event is about to occur, occurs, or has occurred or there are lingering 
effects from such an event within the period of time beginning five 
business days prior to the date the submission is due. For the purposes 
of this section, a force majeure event is defined as an event that will 
be or has been caused by circumstances beyond the control of the 
affected facility, its contractors, or any entity controlled by the 
affected facility that prevents the owner or operator from complying 
with the requirement to submit a report electronically within the time 
period prescribed. Examples of such events are acts of nature (e.g., 
hurricanes, earthquakes, or floods), acts of war or terrorism, or 
equipment failure or safety hazard beyond the control of the affected 
facility (e.g., large scale power outage).
    (2) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (3) The owner or operator must provide to the Administrator:
    (i) A written description of the force majeure event;

[[Page 43132]]

    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which the owner or operator proposes to report, or 
if the owner or operator has already met the reporting requirement at 
the time of the notification, the date the report was submitted.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.

0
38. Amend Sec.  60.708 by revising paragraph (b) to read as follows:


Sec.  60.708  Delegation of authority.

* * * * *
    (b) Authorities which will not be delegated to States: Sec.  
60.703(e) and approval of an alternative to any electronic reporting to 
the EPA required by this subpart.

0
39. Add subpart RRRa to read as follows:

Subpart RRRa--Standards of Performance for Volatile Organic 
Compound Emissions From Synthetic Organic Chemical Manufacturing 
Industry (SOCMI) Reactor Processes for Which Construction, 
Reconstruction, or Modification Commenced After April 25, 2023

Sec.
60.700a Am I subject to this subpart?
60.701a What definitions must I know?
60.702a What standards and associated requirements must I meet?
60.703a What are my monitoring, installation, operation, and 
maintenance requirements?
60.704a What test methods and procedures must I use to determine 
compliance with the standards?
60.705a What records must I keep and what reports must I submit?
60.706a What do the terms associated with reconstruction mean for 
this subpart?
60.707a What are the chemicals that I must produce to be affected by 
subpart RRRa?
60.708a [Reserved]
60.709a What are my requirements if I use a flare to comply with 
this subpart?
60.710a What are my requirements for closed vent systems?
Table 1 to Subpart RRRa of Part 60--Emission Limits and Standards 
for Vent Streams
Table 2 to Subpart RRRa of Part 60--Monitoring Requirements for 
Complying With 98 Weight-Percent Reduction of Total Organic 
Compounds Emissions or a Limit of 20 Parts per Million by Volume
Table 3 to Subpart RRRa of Part 60--Operating Parameters, Operating 
Parameter Limits and Data Monitoring, Recordkeeping and Compliance 
Frequencies
Table 4 to Subpart RRRa of Part 60--Calibration and Quality Control 
Requirements for Continuous Parameter Monitoring System (CPMS)


Sec.  60.700a  Am I subject to this subpart?

    (a) You are subject to the provisions of this subpart if you 
operate an affected facility designated in paragraph (b) of this 
section that is part of a process unit that produces any of the 
chemicals listed in Sec.  60.707a as a product, co-product, by-product, 
or intermediate, except as provided in paragraph (c) of this section.
    (b) The affected facility is any of the following for which 
construction, modification, or reconstruction commenced after April 25, 
2023:
    (1) Each reactor process not discharging its vent stream into a 
recovery system.
    (2) Each combination of a reactor process and the recovery system 
into which its vent stream is discharged.
    (3) Each combination of two or more reactor processes and the 
common recovery system into which their vent streams are discharged.
    (c) Exemptions from the provisions of paragraph (a) of this section 
are as follows:
    (1) Any reactor process that is designed and operated as a batch 
operation is not an affected facility.
    (2) Each affected facility in a process unit with a total design 
capacity for all chemicals produced within that unit of less than 1 
gigagram per year (1,100 tons per year) is exempt from all provisions 
of this subpart except for the recordkeeping and reporting requirements 
in Sec.  60.705a(h), (k)(6), and (p).
    (3) Each affected facility operated with a vent stream flow rate 
less than 0.011 scm/min is exempt from all provisions of this subpart 
except for the test method and procedure and the recordkeeping and 
reporting requirements in Sec. Sec.  60.704a(e) and 60.705a(i), (k)(7), 
and (q).
    (4) If the vent stream from an affected facility is routed to a 
distillation unit subject to subpart NNNa of this part and has no other 
releases to the air except for a pressure relief valve, the facility is 
exempt from all provisions of this subpart except for Sec.  60.705a(r).
    (5) Any reactor process operating as part of a process unit which 
produces beverage alcohols, or which uses, contains, and produces no 
VOC is not an affected facility.
    (6) Any reactor process that is subject to the provisions of 
subpart DDD is not an affected facility.
    (7) Each affected facility operated with a concentration of total 
organic compounds (TOC) (less methane and ethane) in the vent stream 
less than 300 ppmv as measured by Method 18 or a concentration of TOC 
in the vent stream less than 150 ppmv as measured by Method 25A is 
exempt from all provisions of this subpart except for the test method 
and procedure and the reporting and recordkeeping requirements in Sec.  
60.704a(f) and Sec.  60.705a(j), (k)(8), and (s).
    (8) A vent stream going to a fuel gas system as defined in Sec.  
63.701a.


Sec.  60.701a  What definitions must I know?

    As used in this subpart, all terms not defined herein have the 
meaning given them in the Clean Air Act and subpart A of this part.
    Batch operation means any noncontinuous reactor process that is not 
characterized by steady-state conditions and in which reactants are not 
added and products are not removed simultaneously.
    Boiler means any enclosed combustion device that extracts useful 
energy in the form of steam and is not an incinerator.
    Breakthrough means the time when the level of TOC, measured at the 
outlet of the first bed, has been detected is at the highest 
concentration allowed to be discharged from the adsorber system and 
indicates that the adsorber bed should be replaced.
    By compound means by individual stream components, not carbon 
equivalents.
    Car-seal means a seal that is placed on a device that is used to 
change the position of a valve (e.g., from opened to closed) in such a 
way that the position of the valve cannot be changed without breaking 
the seal.
    Closed vent system means a system that is not open to the 
atmosphere and is composed of piping, ductwork, connections, and, if 
necessary, flow inducing devices that transport gas or vapor from an 
emission point to a control device.
    Combustion device means an individual unit of equipment, such as an 
incinerator, flare, boiler, or process heater, used for combustion of a 
vent stream discharged from the process vent.
    Continuous recorder means a data recording device recording an 
instantaneous data value at least once every 15 minutes.
    Flame zone means the portion of the combustion chamber in a boiler 
or

[[Page 43133]]

process heater occupied by the flame envelope.
    Flow indicator means a device which indicates whether gas flow is 
present in a line.
    Fuel gas means gases that are combusted to derive useful work or 
heat.
    Fuel gas system means the offsite and onsite piping and flow and 
pressure control system that gathers gaseous stream(s) generated by 
onsite operations, may blend them with other sources of gas, and 
transports the gaseous stream for use as fuel gas in combustion devices 
or in in-process combustion equipment such as furnaces and gas turbines 
either singly or in combination.
    Halogenated vent stream means any vent stream determined to have a 
total concentration (by volume) of compounds containing halogens of 20 
ppmv (by compound) or greater.
    Incinerator means an enclosed combustion device that is used for 
destroying organic compounds. If there is energy recovery, the energy 
recovery section and the combustion chambers are not of integral 
design. That is, the energy recovery section and the combustion section 
are not physically formed into one manufactured or assembled unit but 
are joined by ducts or connections carrying flue gas.
    Pressure-assisted multi-point flare means a flare system consisting 
of multiple flare burners in staged arrays whereby the vent stream 
pressure is used to promote mixing and smokeless operation at the flare 
burner tips. Pressure-assisted multi-point flares are designed for 
smokeless operation at velocities up to Mach = 1 conditions (i.e., 
sonic conditions), can be elevated or at ground level, and typically 
use cross-lighting for flame propagation to combust any flare vent 
gases sent to a particular stage of flare burners.
    Primary fuel means the fuel fired through a burner or a number of 
similar burners. The primary fuel provides the principal heat input to 
the device, and the amount of fuel is sufficient to sustain operation 
without the addition of other fuels.
    Process heater means a device that transfers heat liberated by 
burning fuel directly to process streams or to heat transfer liquids 
other than water.
    Process unit means equipment assembled and connected by pipes or 
ducts to produce, as intermediates or final products, one or more of 
the chemicals in Sec.  60.707a. A process unit can operate 
independently if supplied with sufficient feed or raw materials and 
sufficient product storage facilities.
    Product means any compound or chemical listed in Sec.  60.707a 
which is produced for sale as a final product as that chemical, or for 
use in the production of other chemicals or compounds. By-products, co-
products, and intermediates are considered to be products.
    Reactor processes are unit operations in which one or more 
chemicals, or reactants other than air, are combined or decomposed in 
such a way that their molecular structures are altered and one or more 
new organic compounds are formed.
    Recovery device means an individual unit of equipment, such as an 
absorber, carbon adsorber, or condenser, capable of and used for the 
purpose of recovering chemicals for use, reuse, or sale.
    Recovery system means an individual recovery device or series of 
such devices applied to the same vent stream.
    Relief valve means a valve used only to release an unplanned, 
nonroutine discharge. A relief valve discharge results from an operator 
error, a malfunction such as a power failure or equipment failure, or 
other unexpected cause that requires immediate venting of gas from 
process equipment in order to avoid safety hazards or equipment damage.
    Secondary fuel means a fuel fired through a burner other than a 
primary fuel burner. The secondary fuel may provide supplementary heat 
in addition to the heat provided by the primary fuel.
    Total organic compounds or TOC means those compounds measured 
according to the procedures of Method 18 of appendix A-6 of this part 
or the concentration of organic compounds measured according to the 
procedures in Method 21 or Method 25A of appendix A-7 of this part.
    Vent stream means any gas stream discharged directly from a reactor 
process to the atmosphere or indirectly to the atmosphere after 
diversion through other process equipment. The vent stream excludes and 
equipment leaks, including, but not limited to, pumps, compressors, and 
valves.


Sec.  60.702a  What standards and associated requirements must I meet?

    (a) You must comply with the emission limits and standards 
specified in Table 1 to this subpart and the requirements specified in 
paragraphs (b) and (c) of this section for each vent stream on and 
after the date on which the initial performance test required by 
Sec. Sec.  60.8 and 60.704a is completed, but not later than 60 days 
after achieving the maximum production rate at which the affected 
facility will be operated, or 180 days after the initial start-up, 
whichever date comes first. The standards in this section apply at all 
times, including periods of startup, shutdown and malfunction. As 
provided in Sec.  60.11(f), this provision supersedes the exemptions 
for periods of startup, shutdown and malfunction in the general 
provisions in subpart A of this part.
    (b) The following release events from an affected facility are a 
violation of the emission limits and standards specified in table 1 to 
this subpart.
    (1) Any relief valve discharge to the atmosphere of a vent stream.
    (2) The use of a bypass line at any time on a closed vent system to 
divert emissions to the atmosphere, or to a control device or recovery 
device not meeting the requirements specified in Sec.  60.703a.
    (c) You may designate a vent stream as a maintenance vent if the 
vent is only used as a result of startup, shutdown, maintenance, or 
inspection of equipment where equipment is emptied, depressurized, 
degassed, or placed into service. You must comply with the applicable 
requirements in paragraphs (c)(1) through (3) of this section for each 
maintenance vent. Any vent stream designated as a maintenance vent is 
only subject to the maintenance vent provisions in this paragraph (c) 
and the associated recordkeeping and reporting requirements in Sec.  
60.705a(g), respectively.
    (1) Prior to venting to the atmosphere, remove process liquids from 
the equipment as much as practical and depressurize the equipment to 
either: A flare meeting the requirements of Sec.  60.709a, as 
applicable, or using any combination of a non-flare control device or 
recovery device meeting the requirements in table 1 to this subpart 
until one of the following conditions, as applicable, is met.
    (i) The vapor in the equipment served by the maintenance vent has a 
lower explosive limit (LEL) of less than 10 percent.
    (ii) If there is no ability to measure the LEL of the vapor in the 
equipment based on the design of the equipment, the pressure in the 
equipment served by the maintenance vent is reduced to 5 pounds per 
square inch gauge (psig) or less. Upon opening the maintenance vent, 
active purging of the equipment cannot be used until the LEL of the 
vapors in the maintenance vent (or inside the equipment if the 
maintenance is a hatch or similar type of opening) is less than 10 
percent.
    (iii) The equipment served by the maintenance vent contains less 
than 50 pounds of total VOC.

[[Page 43134]]

    (iv) If, after applying best practices to isolate and purge 
equipment served by a maintenance vent, none of the applicable 
criterion in paragraphs (c)(1)(i) through (iii) of this section can be 
met prior to installing or removing a blind flange or similar equipment 
blind, then the pressure in the equipment served by the maintenance 
vent must be reduced to 2 psig or less before installing or removing 
the equipment blind. During installation or removal of the equipment 
blind, active purging of the equipment may be used provided the 
equipment pressure at the location where purge gas is introduced 
remains at 2 psig or less.
    (2) Except for maintenance vents complying with the alternative in 
paragraph (c)(1)(iii) of this section, you must determine the LEL or, 
if applicable, equipment pressure using process instrumentation or 
portable measurement devices and follow procedures for calibration and 
maintenance according to manufacturer's specifications.
    (3) For maintenance vents complying with the alternative in 
paragraph (c)(1)(iii) of this section, you must determine mass of VOC 
in the equipment served by the maintenance vent based on the equipment 
size and contents after considering any contents drained or purged from 
the equipment. Equipment size may be determined from equipment design 
specifications. Equipment contents may be determined using process 
knowledge.


Sec.  60.703a  What are my monitoring, installation, operation, and 
maintenance requirements?

    (a) Except as specified in paragraphs (a)(5) through (7) of this 
section, if you use a non-flare control device or recovery system to 
comply with the TOC emission limit specified in table 1 to this 
subpart, then you must comply with paragraphs (a)(1) through (4), (b), 
and (c) of this section.
    (1) Install a continuous parameter monitoring system(s) (CPMS) and 
monitor the operating parameter(s) applicable to the control device or 
recovery system as specified in table 2 to this subpart or established 
according to paragraph (c) of this section.
    (2) Establish the applicable minimum, maximum, or range for the 
operating parameter limit as specified in Table 3 to this subpart or 
established according to paragraph (c) of this section by calculating 
the value(s) as the arithmetic average of operating parameter 
measurements recorded during the three test runs conducted for the most 
recent performance test. You may operate outside of the established 
operating parameter limit(s) during subsequent performance tests in 
order to establish new operating limits. You must include the updated 
operating limits with the performance test results submitted to the 
Administrator pursuant to Sec.  60.705a(b). Upon establishment of a new 
operating limit, you must thereafter operate under the new operating 
limit. If the Administrator determines that you did not conduct the 
performance test in accordance with the applicable requirements or that 
the operating limit established during the performance test does not 
correspond to the conditions specified in Sec.  60.704a(a), then you 
must conduct a new performance test and establish a new operating 
limit.
    (3) Monitor, record, and demonstrate continuous compliance using 
the minimum frequencies specified in Table 3 to this subpart or 
established according to paragraph (c) of this section.
    (4) Comply with the calibration and quality control requirements as 
specified in table 4 to this subpart or established according to 
paragraph (c) of this section that are applicable to the CPMS used.
    (5) Any vent stream introduced with primary fuel into a boiler or 
process heater is exempt from the requirements specified in paragraphs 
(a)(1) through (4) of this section.
    (6) If you vent emissions through a closed vent system to an 
adsorber(s) that cannot be regenerated or a regenerative adsorber(s) 
that is regenerated offsite, then you must install a system of two or 
more adsorber units in series and comply with the requirements 
specified in paragraphs (a)(6)(i) through (iii) of this section in 
addition to the requirements specified in paragraphs (a)(1) through (4) 
of this section.
    (i) Conduct an initial performance test or design evaluation of the 
adsorber and establish the breakthrough limit and adsorber bed life.
    (ii) Monitor the TOC concentration through a sample port at the 
outlet of the first adsorber bed in series according to the schedule in 
paragraph (a)(6)(iii)(B) of this section. You must measure the 
concentration of TOC using either a portable analyzer, in accordance 
with Method 21 of appendix A-7 of this part using methane, propane, or 
isobutylene as the calibration gas or Method 25A of appendix A-7 of 
this part using methane or propane as the calibration gas.
    (iii) Comply with paragraph (a)(6)(iii)(A) of this section and 
comply with the monitoring frequency according to paragraph 
(a)(6)(iii)(B) of this section.
    (A) The first adsorber in series must be replaced immediately when 
breakthrough, as defined in Sec.  60.611a, is detected between the 
first and second adsorber. The original second adsorber (or a fresh 
canister) will become the new first adsorber and a fresh adsorber will 
become the second adsorber. For purposes of this paragraph 
(a)(6)(iii)(A), ``immediately'' means within 8 hours of the detection 
of a breakthrough for adsorbers of 55 gallons or less, and within 24 
hours of the detection of a breakthrough for adsorbers greater than 55 
gallons. You must monitor at the outlet of the first adsorber within 3 
days of replacement to confirm it is performing properly.
    (B) Based on the adsorber bed life established according to 
paragraph (a)(6)(i) of this section and the date the adsorbent was last 
replaced, conduct monitoring to detect breakthrough at least monthly if 
the adsorbent has more than 2 months of life remaining, at least weekly 
if the adsorbent has between 2 months and 2 weeks of life remaining, 
and at least daily if the adsorbent has 2 weeks or less of life 
remaining.
    (7) If you install a continuous emissions monitoring system (CEMS) 
to demonstrate compliance with the TOC standard in Table 1 of this 
subpart, you must comply with the requirements specified in Sec.  
60.704a(g) in lieu of the requirements specified in paragraphs (a)(1) 
through (4) and (c) of this section.
    (b) If you vent emissions through a closed vent system to a boiler 
or process heater, then the vent stream must be introduced into the 
flame zone of the boiler or process heater.
    (c) If you seek to demonstrate compliance with the standards 
specified under Sec.  60.702a with control devices other than an 
incinerator, boiler, process heater, or flare; or recovery devices 
other than an absorber, condenser, or carbon adsorber, you shall 
provide to the Administrator prior to conducting the initial 
performance test information describing the operation of the control 
device or recovery device and the parameter(s) which would indicate 
proper operation and maintenance of the device and how the parameter(s) 
are indicative of control of TOC emissions. The Administrator may 
request further information and will specify appropriate monitoring 
procedures or requirements, including operating parameters to be 
monitored, averaging times for determining compliance with the 
operating parameter limits, and ongoing calibration and quality control 
requirements.

[[Page 43135]]

Sec.  60.704a  What test methods and procedures must I use to determine 
compliance with the standards?

    (a) For the purpose of demonstrating compliance with the emission 
limits and standards specified in table 1 to this subpart, all affected 
facilities must be run at full operating conditions and flow rates 
during any performance test. Performance tests are not required if you 
determine compliance using a CEMS that meets the requirements outlined 
in paragraph (g) of this section.
    (1) Conduct initial performance tests no later than the date 
required by Sec.  60.8(a).
    (2) Conduct subsequent performance tests no later than 60 calendar 
months after the previous performance test.
    (b) The following methods in appendix A to this part, except as 
provided in Sec.  60.8(b), must be used as reference methods to 
determine compliance with the emission limit or percent reduction 
efficiency specified in table 1 to this subpart for non-flare control 
devices and/or recovery systems.
    (1) Method 1 or 1A of appendix A-1 to this part, as appropriate, 
for selection of the sampling sites. The inlet sampling site for 
determination of vent stream molar composition or TOC (less methane and 
ethane) reduction efficiency shall be prior to the inlet of the control 
device or, if equipped with a recovery system, then prior to the inlet 
of the first recovery device in the recovery system.
    (2) Method 2, 2A, 2C, or 2D of appendix A-1 to this part, as 
appropriate, for determination of the gas volumetric flow rates.
    (3) Method 3A of appendix A-2 to this part or the manual method in 
ANSI/ASME PTC 19.10-1981--Part 10 (incorporated by reference, see Sec.  
[thinsp]60.17) must be used to determine the oxygen concentration 
(%O2d) for the purposes of determining compliance with the 20 ppmv 
limit. The sampling site must be the same as that of the TOC samples, 
and the samples must be taken during the same time that the TOC samples 
are taken. The TOC concentration corrected to 3 percent O2 
(Cc) must be computed using the following equation:

Equation 1 to Paragraph (b)(3)
[GRAPHIC] [TIFF OMITTED] TR16MY24.047

Where:

Cc = Concentration of TOC corrected to 3 percent 
O2, dry basis, ppm by volume.
CTOC = Concentration of TOC (minus methane and ethane), 
dry basis, ppm by volume.
%O2d = Concentration of O2, dry basis, percent 
by volume.

    (4) Method 18 of appendix A-6 to this part to determine the 
concentration of TOC in the control device outlet or in the outlet of 
the final recovery device in a recovery system, and to determine the 
concentration of TOC in the inlet when the reduction efficiency of the 
control device or recovery system is to be determined. ASTM D6420-18 
(incorporated by reference, see Sec.  60.17) may be used in lieu of 
Method 18, if the target compounds are all known and are all listed in 
section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 may not be 
used for methane and ethane; and ASTM D6420-18 must not be used as a 
total VOC method.
    (i) The minimum sampling time for each run must be 1 hour in which 
either an integrated sample or at least four grab samples must be 
taken. If grab sampling is used, then the samples must be taken at 
approximately 15-minute intervals.
    (ii) The emission reduction (R) of TOC (minus methane and ethane) 
must be determined using the following equation:

Equation 2 to Paragraph (b)(4)(ii)
[GRAPHIC] [TIFF OMITTED] TR16MY24.048

Where:

R = Emission reduction, percent by weight.
Ei = Mass rate of TOC entering the control device or 
recovery system, kg TOC/hr.
Eo = Mass rate of TOC discharged to the atmosphere, kg 
TOC/hr.

    (iii) The mass rates of TOC (Ei, Eo) must be 
computed using the following equations:

Equations 3 and 4 to Paragraph (b)(4)(iii)
[GRAPHIC] [TIFF OMITTED] TR16MY24.049

Where:

Cij, Coj = Concentration of sample component 
``j'' of the gas stream at the inlet and outlet of the control 
device or recovery system, respectively, dry basis, ppm by volume.
Mij, Moj = Molecular weight of sample 
component ``j'' of the gas stream at the inlet and outlet of the 
control device or recovery system, respectively, g/g-mole (lb/lb-
mole).
Qi, Qo = Flow rate of gas stream at the inlet 
and outlet of the control device or recovery system, respectively, 
dscm/min (dscf/hr).
K2 = Constant, 2.494 x 10\-6\ (l/ppm) (g-mole/scm) (kg/g) 
(min/hr), where standard temperature for (g-mole/scm) is 20 [deg]C 
(metric units); or
= Constant, 1.557 x 10-7 (1/ppm)(lb-mole/scf)(min/hr), where 
standard temperature for (lb-mole/scf) is 68 [deg]F (English units).


[[Page 43136]]


    (iv) The TOC concentration (CTOC) is the sum of the 
individual components and must be computed for each run using the 
following equation:

Equation 5 to Paragraph (b)(4)(iv)
[GRAPHIC] [TIFF OMITTED] TR16MY24.050

Where:

CTOC = Concentration of TOC (minus methane and ethane), 
dry basis, ppm by volume.
Cj = Concentration of sample components ``j'', dry basis, 
ppm by volume.
n = Number of components in the sample.

    (c) The requirement for initial and subsequent performance tests 
are waived, in accordance with Sec.  60.8(b), for the following:
    (1) When a boiler or process heater with a design heat input 
capacity of 44 MW (150 million Btu/hour) or greater is used to seek 
compliance with Sec.  60.702a(a).
    (2) When a vent stream is introduced into a boiler or process 
heater with the primary fuel.
    (3) When a boiler or process heater burning hazardous waste is used 
for which the owner or operator:
    (i) Has been issued a final permit under 40 CFR part 270 and 
complies with the requirements of 40 CFR part 266, subpart H;
    (ii) Has certified compliance with the interim status requirements 
of 40 CFR part 266, subpart H;
    (iii) Has submitted a Notification of Compliance under 40 CFR 
63.1207(j) and complies with the requirements of 40 CFR part 63, 
subpart EEE; or
    (iv) Complies with 40 CFR part 63, subpart EEE, and will submit a 
Notification of Compliance under 40 CFR 63.1207(j) by the date the 
owner or operator would have been required to submit the initial 
performance test report for this subpart.
    (4) The Administrator reserves the option to require testing at 
such other times as may be required, as provided for in section 114 of 
the Act.
    (d) For purposes of complying with the 98 weight-percent reduction 
in Sec.  60.702a(a), if the vent stream entering a boiler or process 
heater with a design capacity less than 44 MW (150 million Btu/hour) is 
introduced with the combustion air or as secondary fuel, the weight-
percent reduction of TOC (minus methane and ethane) across the 
combustion device shall be determined by comparing the TOC (minus 
methane and ethane) in all combusted vent streams, primary fuels, and 
secondary fuels with the TOC (minus methane and ethane) exiting the 
combustion device.
    (e) Any owner or operator subject to the provisions of this subpart 
seeking to demonstrate compliance with Sec.  60.700a(c)(3) shall use 
Method 2, 2A, 2C, or 2D of appendix A-1 to this part, as appropriate, 
for determination of volumetric flow rate. The owner or operator must 
conduct three velocity traverses and determine the volumetric flow rate 
for each traverse. If the pipe or duct is smaller than four inches in 
diameter, the owner operator may conduct the measurement at the 
centroid of the duct instead of conducting a traverse; the measurement 
period must be at least five minutes long and data must be recorded at 
least once every 30 seconds. Owners and operators who conduct the 
determination with Method 2A or 2D must record volumetric flow rate 
every 30 seconds for at least five minutes.
    (f) Each owner or operator seeking to demonstrate that a reactor 
process vent stream has a TOC concentration for compliance with the low 
concentration exemption in Sec.  60.700a(c)(7) shall conduct an initial 
test to measure TOC concentration.
    (1) The sampling site shall be selected as specified in paragraph 
(d)(1)(i) of this section.
    (2) Method 18 of appendix A-6 or Method 25A of appendix A-7 to this 
part shall be used to measure concentration. ASTM D6420-18 
(incorporated by reference, see Sec.  60.17) may be used in lieu of 
Method 18, if the target compounds are all known and are all listed in 
Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 may not be 
used for methane and ethane; and ASTM D6420-18 must not be used as a 
total VOC method.
    (3) Where Method 18 of appendix A-6 to this part is used to qualify 
for the low concentration exclusion in Sec.  60.700a(c)(7), the 
procedures in paragraphs (b)(4)(i) and (iv) of this section shall be 
used to measure TOC concentration, and the procedures of paragraph 
(b)(3) of this section shall be used to correct the TOC concentration 
to 3 percent oxygen. To qualify for the exclusion, the results must 
demonstrate that the concentration of TOC, corrected to 3 percent 
oxygen, is below 300 ppm by volume.
    (4) Where Method 25A of appendix A-7 to this part is used, the 
following procedures shall be used to calculate ppm by volume TOC 
concentration, corrected to 3 percent oxygen:
    (i) Method 25A of appendix A-7 to this part shall be used only if a 
single organic compound is greater than 50 percent of total TOC, by 
volume, in the reactor process vent stream. This compound shall be the 
principal organic compound.
    (ii) The principal organic compound may be determined by either 
process knowledge or test data collected using an appropriate EPA 
Reference Method. Examples of information that could constitute process 
knowledge include calculations based on material balances, process 
stoichiometry, or previous test results provided the results are still 
relevant to the current reactor process vent stream conditions.
    (iii) The principal organic compound shall be used as the 
calibration gas for Method 25A of appendix A-7 to this part.
    (iv) The span value for Method 25A of appendix A-7 to this part 
shall be 300 ppmv.
    (v) Use of Method 25A of appendix A-7 to this part is acceptable if 
the response from the high-level calibration gas is at least 20 times 
the standard deviation of the response from the zero calibration gas 
when the instrument is zeroed on the most sensitive scale.
    (vi) The owner or operator shall demonstrate that the concentration 
of TOC including methane and ethane measured by Method 25A of appendix 
A-7 to this part, corrected to 3 percent oxygen, is below 150 ppm by 
volume to qualify for the low concentration exclusion in Sec.  
60.700a(c)(7).
    (vii) The concentration of TOC shall be corrected to 3 percent 
oxygen using the procedures and equation in paragraph (b)(3) of this 
section.
    (g) If you use a CEMS to demonstrate initial and continuous 
compliance with the TOC standard in table 1 of this subpart, each CEMS 
must be installed, operated and maintained according to the 
requirements in Sec.  60.13 and paragraphs (f)(1) through (5) of this 
section.
    (1) You must use a CEMS that is capable of measuring the target 
analyte(s) as demonstrated using either process knowledge of the 
control device inlet stream or the screening procedures of Method 18 of 
appendix A-6 to this

[[Page 43137]]

part on the control device inlet stream. If your CEMS is located after 
a combustion device and inlet stream to that device includes methanol 
or formaldehyde, you must use a CEMS which meets the requirements in 
Performance Specifications 9 or 15 of appendix B to this part.
    (2) Each CEMS must be installed, operated, and maintained according 
to the applicable performance specification of appendix B of this part 
and the applicable quality assurance procedures of appendix F to this 
part. Locate the sampling probe or other interface at a measurement 
location such that you obtain representative measurements of emissions 
from the affected facility.
    (3) Conduct a performance evaluation of each CEMS within 180 days 
of installation of the monitoring system. Conduct subsequent 
performance evaluations of the CEMS no later than 12 calendar months 
after the previous performance evaluation. The results each performance 
evaluation must be submitted in accordance with Sec.  60.705a(b)(1).
    (4) You must determine TOC concentration according to one of the 
following options. The span value of the TOC CEMS must be approximately 
2 times the emission standard specified in table 1 of this subpart.
    (i) For CEMS meeting the requirements of Performance Specification 
15 of appendix B to this part, determine the target analyte(s) for 
calibration using either process knowledge of the control device inlet 
stream or the screening procedures of Method 18 of appendix A-6 to this 
part on the control device inlet stream. The individual analytes used 
to quantify TOC must represent 98 percent of the expected mass of TOC 
present in the stream. Report the results of TOC as equivalent to 
carbon (C1).
    (ii) For CEMS meeting the requirements of Performance Specification 
9 of appendix B to this part, determine the target analyte(s) for 
calibration using either process knowledge of the control device inlet 
stream or the screening procedures of Method 18 of appendix A-6 to this 
part on the control device inlet stream. The individual analytes used 
to quantify TOC must represent 98 percent of the expected mass of TOC 
present in the stream. Report the results of TOC as equivalent to 
carbon (C1).
    (iii) For CEMS meeting the requirements of Performance 
Specification 8 of appendix B to this part used to monitor performance 
of a combustion device, calibrate the instrument on the predominant 
organic HAP and report the results as carbon (C1), and use Method 25A 
of appendix A-7 to this part as the reference method for the relative 
accuracy tests. You must also comply with procedure 1 of appendix F to 
this part.
    (iv) For CEMS meeting the requirements of Performance Specification 
8 of appendix B to this part used to monitor performance of a 
noncombustion device, determine the predominant organic compound using 
either process knowledge or the screening procedures of Method 18 of 
appendix A-6 to this part on the control device inlet stream. Calibrate 
the monitor on the predominant organic compound and report the results 
as C1. Use Method 25A of appendix A-7 to this part as the 
reference method for the relative accuracy tests. You must also comply 
with procedure 1 of appendix F to this part.
    (5) You must determine stack oxygen concentration at the same 
location where you monitor TOC concentration with a CEMS that meets the 
requirements of Performance Specification 3 of appendix B of this part. 
The span value of the oxygen CEMS must be approximately 25 percent 
oxygen. Use Method 3A of appendix A-2 to this part as the reference 
method for the relative accuracy tests.
    (6) You must maintain written procedures for your CEMS. At a 
minimum, the procedures must include the information in paragraph 
(f)(6)(i) through (vi) of this section:
    (i) Description of CEMS installation location.
    (ii) Description of the monitoring equipment, including the 
manufacturer and model number for all monitoring equipment components 
and the span of the analyzer.
    (iii) Routine quality control and assurance procedures.
    (iv) Conditions that would trigger a CEMS performance evaluation, 
which must include, at a minimum, a newly installed CEMS; a process 
change that is expected to affect the performance of the CEMS; and the 
Administrator's request for a performance evaluation under section 114 
of the Clean Air Act.
    (v) Ongoing operation and maintenance procedures.
    (vi) Ongoing recordkeeping and reporting procedures.


Sec.  60.705a  What records must I keep and what reports must I submit?

    (a) You must notify the Administrator of the specific provisions in 
table 1 to this subpart or Sec.  60.702a(c) with which you have elected 
to comply. Notification shall be submitted with the notification of 
initial start-up required by Sec.  60.7(a)(3). If you elect at a later 
date to comply with an alternative provision of Sec.  60.702a, then you 
must notify the Administrator 90 days before implementing a change and, 
upon implementing the change, you must conduct a performance as 
specified by Sec.  60.704a within 180 days.
    (b) If you use a non-flare control device or recovery system to 
comply with the TOC emission limit specified in table 1 to this 
subpart, then you must keep an up-to-date, readily accessible record of 
the data measured during each performance test to show compliance with 
the TOC emission limit. You must also include all of the data you use 
to comply with Sec.  60.703a(a)(2). The same data specified in this 
paragraph must also be submitted in the initial performance test 
required in Sec.  60.8 and the reports of all subsequently required 
performance tests where either the emission reduction efficiency of a 
combustion device or recovery system or outlet concentration of TOC is 
determined. Alternatively, you must keep records of each CEMS 
performance evaluation.
    (1) Within 60 days after the date of completing each performance 
test or CEMS performance evaluation required by this subpart, you must 
submit the results of the performance test or performance evaluation 
following the procedures specified in paragraph (l) of this section. 
Data collected using test methods and performance evaluations of CEMS 
measuring relative accuracy test audit (RATA) pollutants supported by 
the EPA's Electronic Reporting Tool (ERT) as listed on the EPA's ERT 
website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test or performance 
evaluation must be submitted in a file format generated through the use 
of the EPA's ERT. Alternatively, owners and operators may submit an 
electronic file consistent with the extensible markup language (XML) 
schema listed on the EPA's ERT website. Data collected using test 
methods and performance evaluations of CEMS measuring RATA pollutants 
that are not supported by the EPA's ERT as listed on the EPA's ERT 
website at the time of the test must be included as an attachment in 
the ERT or alternate electronic file.
    (2) If you use a boiler or process heater with a design heat input 
capacity of 44 MW (150 million Btu/hour) or greater to comply with the 
TOC emission limit specified in table 1 to this subpart, then you are 
not required to submit a report containing performance test data; 
however, you

[[Page 43138]]

must submit a description of the location at which the vent stream is 
introduced into the boiler or process heater.
    (c) If you use a non-flare control device or recovery system to 
comply with the TOC emission limit specified in table 1 to this 
subpart, then you must keep up-to-date, readily accessible records of 
periods of operation during which the operating parameter limits 
established during the most recent performance test are exceeded or 
periods of operation where the TOC CEMS, averaged on a 3-hour block 
basis, indicate an exceedance of the emission standard in table 1 of 
this subpart. Additionally, you must record all periods when the TOC 
CEMS is inoperable. The Administrator may at any time require a report 
of these data. Periods of operation during which the operating 
parameter limits established during the most recent performance tests 
are exceeded are defined as follows:
    (1) For absorbers:
    (i) All 3-hour periods of operation during which the average 
absorbing liquid temperature was above the maximum absorbing liquid 
temperature established during the most recent performance test; and
    (ii) All 3-hour periods of operation during which the average 
absorbing liquid specific gravity was outside the exit specific gravity 
range (i.e., more than 0.1 unit above, or more than 0.1 unit below, the 
average absorbing liquid specific gravity) established during the most 
recent performance test.
    (2) For boilers or process heaters:
    (i) Whenever there is a change in the location at which the vent 
stream is introduced into the flame zone as required under Sec.  
60.703a(b); and
    (ii) If the boiler or process heater has a design heat input 
capacity of less than 44 MW (150 million Btu/hr), then all 3-hour 
periods of operation during which the average firebox temperature was 
below the minimum firebox temperature during the most recent 
performance test.
    (3) For catalytic incinerators:
    (i) All 3-hour periods of operation during which the average 
temperature of the vent stream immediately before the catalyst bed is 
below the minimum temperature of the vent stream established during the 
most recent performance test.
    (ii) All 3-hour periods of operation during which the average 
temperature difference across the catalyst bed is less than the average 
temperature difference of the device established during the most recent 
performance test.
    (4) For carbon adsorbers:
    (i) All carbon bed regeneration cycles during which the total mass 
stream flow or the total volumetric stream flow was below the minimum 
flow established during the most recent performance test, or
    (ii) All carbon bed regeneration cycles during which the 
temperature of the carbon bed after regeneration (and after completion 
of any cooling cycle(s)) was greater than the maximum carbon bed 
temperature (in degrees Celsius) established during the most recent 
performance test.
    (5) For condensers, all 3-hour periods of operation during which 
the average exit (product side) condenser operating temperature was 
above the maximum exit (product side) operating temperature established 
during the most recent performance test.
    (6) For scrubbers used to control halogenated vent streams:
    (i) All 3-hour periods of operation during which the average pH of 
the scrubber effluent is below the minimum pH of the scrubber effluent 
established during the most recent performance test,
    (ii) All 3-hour periods of operation during which the average 
influent liquid flow to the scrubber is below the minimum influent 
liquid flow to the scrubber established during the most recent 
performance test, or
    (iii) All 3-hour periods of operation during which the average 
liquid-to-gas ratio flow of the scrubber is below the minimum liquid-
to-gas ratio of the scrubber established during the most recent 
performance test.
    (7) For thermal incinerators, all 3-hour periods of operation 
during which the average firebox temperature was below the minimum 
firebox temperature established during the most recent performance 
test.
    (8) For all other control devices, all periods (for the averaging 
time specified by the Administrator) when the operating parameter(s) 
established under Sec.  60.703a(c) exceeded the operating limit 
established during the most recent performance test.
    (d) You must keep up-to-date, readily accessible continuous records 
of the flow indication specified in table 2 to this subpart, as well as 
up-to-date, readily accessible records of all periods when the vent 
stream is diverted from the control device or recovery device or has no 
flow rate, including the records as specified in paragraphs (d)(1) and 
(2) of this section.
    (1) For each flow event from a relief valve discharge subject to 
the requirements in Sec.  60.702a(b)(1), you must include an estimate 
of the volume of gas, the concentration of TOC in the gas and the 
resulting emissions of TOC that released to the atmosphere using 
process knowledge and engineering estimates.
    (2) For each flow event from a bypass line subject to the 
requirements in Sec. Sec.  60.702a(b)(2) and 60.710a(e), you must 
maintain records sufficient to determine whether or not the detected 
flow included flow requiring control. For each flow event from a bypass 
line requiring control that is released either directly to the 
atmosphere or to a control device or recovery device not meeting the 
requirements in this subpart, you must include an estimate of the 
volume of gas, the concentration of TOC in the gas and the resulting 
emissions of TOC that bypassed the control device or recovery device 
using process knowledge and engineering estimates.
    (e) If you use a boiler or process heater with a design heat input 
capacity of 44 MW (150 million Btu/hour) or greater to comply with the 
TOC emission limit specified in table 1 to this subpart, then you must 
keep an up-to-date, readily accessible record of all periods of 
operation of the boiler or process heater. (Examples of such records 
could include records of steam use, fuel use, or monitoring data 
collected pursuant to other State or Federal regulatory requirements).
    (f) If you use a flare to comply with the TOC emission standard 
specified in table 1 to this subpart, then you must keep up-to-date, 
readily accessible records of all visible emission readings, heat 
content determinations, flow rate measurements, and exit velocity 
determinations made during the initial visible emissions demonstration 
required by Sec.  63.670(h) of part 63, subpart CC of this chapter, as 
applicable; and all periods during the compliance determination when 
the pilot flame or flare flame is absent.
    (g) For each maintenance vent opening subject to the requirements 
of Sec.  60.702a(c), you must keep the applicable records specified in 
paragraphs (g)(1) through (5) of this section.
    (1) You must maintain standard site procedures used to deinventory 
equipment for safety purposes (e.g., hot work or vessel entry 
procedures) to document the procedures used to meet the requirements in 
Sec.  60.702a(c). The current copy of the procedures must be retained 
and available on-site at all times. Previous versions of the standard 
site procedures, as applicable, must be retained for five years.
    (2) If complying with the requirements of Sec.  60.702a(c)(1)(i), 
and the lower explosive limit at the time of the vessel opening exceeds 
10 percent,

[[Page 43139]]

identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, the date of maintenance vent 
opening, and the lower explosive limit at the time of the vessel 
opening.
    (3) If complying with the requirements of Sec.  60.702a(c)(1)(ii), 
and either the vessel pressure at the time of the vessel opening 
exceeds 5 psig or the lower explosive limit at the time of the active 
purging was initiated exceeds 10 percent, identification of the 
maintenance vent, the process units or equipment associated with the 
maintenance vent, the date of maintenance vent opening, the pressure of 
the vessel or equipment at the time of discharge to the atmosphere and, 
if applicable, the lower explosive limit of the vapors in the equipment 
when active purging was initiated.
    (4) If complying with the requirements of Sec.  60.702a(c)(1)(iii), 
records of the estimating procedures used to determine the total 
quantity of VOC in the equipment and the type and size limits of 
equipment that contain less than 50 pounds of VOC at the time of 
maintenance vent opening. For each maintenance vent opening that 
contains greater than 50 pounds of VOC for which the inventory 
procedures specified in paragraph (g)(1) of this section are not 
followed or for which the equipment opened exceeds the type and size 
limits established in the records specified in this paragraph (g)(4), 
records that identify the maintenance vent, the process units or 
equipment associated with the maintenance vent, the date of maintenance 
vent opening, and records used to estimate the total quantity of VOC in 
the equipment at the time the maintenance vent was opened to the 
atmosphere.
    (5) If complying with the requirements of Sec.  60.702a(c)(1)(iv), 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, records documenting actions taken 
to comply with other applicable alternatives and why utilization of 
this alternative was required, the date of maintenance vent opening, 
the equipment pressure and lower explosive limit of the vapors in the 
equipment at the time of discharge, an indication of whether active 
purging was performed and the pressure of the equipment during the 
installation or removal of the blind if active purging was used, the 
duration the maintenance vent was open during the blind installation or 
removal process, and records used to estimate the total quantity of VOC 
in the equipment at the time the maintenance vent was opened to the 
atmosphere for each applicable maintenance vent opening.
    (h) If you seek to comply with the requirements of this subpart by 
complying with the design production capacity provision in Sec.  
60.700a(c)(2) you must keep up-to-date, readily accessible records of 
any change in equipment or process operation that increases the design 
production capacity of the process unit in which the affected facility 
is located.
    (i) If you seek to comply with the requirements of this subpart by 
complying with the flow rate cutoff in Sec.  60.700a(c)(3) you must 
keep up-to-date, readily accessible records to indicate that the vent 
stream flow rate is less than 0.011 scm/min and of any change in 
equipment or process operation that increases the operating vent stream 
flow rate, including a measurement of the new vent stream flow rate.
    (j) If you seek to comply with the requirements of this subpart by 
complying with the low concentration exemption in Sec.  60.700a(c)(7) 
you must keep up-to-date, readily accessible records of any change in 
equipment or process operation that increases the concentration of the 
vent stream of the affected facility.
    (k) You must submit to the Administrator semiannual reports of the 
information specified in paragraphs (k)(1) through (10) of this 
section. You are exempt from the reporting requirements specified in 
Sec.  60.7(c). If there are no exceedances, periods, or events 
specified in paragraphs (k)(1) through (10) of this section that 
occurred during the reporting period, then you must include a statement 
in your report that no exceedances, periods, and events specified in 
paragraphs (k)(1) through (10) of this section occurred during the 
reporting period. The initial report must be submitted within 6 months 
after the initial start-up-date. On and after July 15, 2024 or once the 
report template for this subpart has been available on the Compliance 
and Emissions Data Reporting Interface (CEDRI) website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 year, 
whichever date is later, you must submit all subsequent reports using 
the appropriate electronic report template on the CEDRI website for 
this subpart and following the procedure specified in paragraph (l) of 
this section. The date report templates become available will be listed 
on the CEDRI website. Unless the Administrator or delegated state 
agency or other authority has approved a different schedule for 
submission of reports, the report must be submitted by the deadline 
specified in this subpart, regardless of the method in which the report 
is submitted. All semiannual reports must include the following general 
information: company name, address (including county), and beginning 
and ending dates of the reporting period.
    (1) Exceedances of monitored parameters recorded under paragraph 
(c) of this section. For each exceedance, the report must include a 
list of the affected facilities or equipment, the monitored parameter 
that was exceeded, the start date and time of the exceedance, the 
duration (in hours) of the exceedance, an estimate of the quantity in 
pounds of each regulated pollutant emitted over any emission limit, a 
description of the method used to estimate the emissions, the cause of 
the exceedance (including unknown cause, if applicable), as applicable, 
and the corrective action taken.
    (2) All periods recorded under paragraph (d) of this section when 
the vent stream is diverted from the control device or recovery device, 
or has no flow rate, including the information specified in paragraphs 
(k)(2)(i) through (iii) of this section.
    (i) For periods when the flow indicator is not operating, report 
the identification of the flow indicator and the start date, start 
time, and duration in hours.
    (ii) For each flow event from a relief valve discharge subject to 
the requirements in Sec.  60.702a(b)(1), the semiannual report must 
include the identification of the relief valve, the start date, start 
time, duration in hours, estimate of the volume of gas in standard 
cubic feet, the concentration of TOC in the gas in parts per million by 
volume and the resulting mass emissions of TOC in pounds that released 
to the atmosphere.
    (iii) For each flow event from a bypass line subject to the 
requirements in Sec. Sec.  60.702a(b)(2) and 60.710a(e)(2), the 
semiannual report must include the identification of the bypass line, 
the start date, start time, duration in hours, estimate of the volume 
of gas in standard cubic feet, the concentration of TOC in the gas in 
parts per million by volume and the resulting mass emissions of TOC in 
pounds that bypass a control device or recovery device.
    (3) All periods when a boiler or process heater was not operating 
(considering the records recorded under paragraph (e) of this section), 
including the start date, start time, and duration in hours of each 
period.
    (4) For each flare subject to the requirements in Sec.  60.709a, 
the

[[Page 43140]]

semiannual report must include an identification of the flare and the 
items specified in Sec.  60.709a(l)(2).
    (5) For each closed vent system subject to the requirements in 
Sec.  60.710a, the semiannual report must include an identification of 
the closed vent system and the items specified in Sec.  60.710a(i).
    (6) Any change in equipment or process operation, as recorded under 
paragraph (h) of this section, that increases the design production 
capacity above the low capacity exemption level in Sec.  60.700a(c)(2) 
and the new capacity resulting from the change for the reactor process 
unit containing the affected facility. These must be reported as soon 
as possible after the change and no later than 180 days after the 
change. These reports may be submitted either in conjunction with 
semiannual reports or as a single separate report. Unless the facility 
qualifies for an exemption under Sec.  60.700a(c), the facility must 
begin compliance with the requirements set forth in Sec.  60.702a.
    (7) Any change in equipment or process operation that increases the 
operating vent stream flow rate above the low flow exemption level in 
Sec.  60.700a(c)(3), including a measurement of the new vent stream 
flow rate, as recorded under paragraph (i) of this section. These must 
be reported as soon as possible after the change and no later than 180 
days after the change. These reports may be submitted either in 
conjunction with semiannual reports or as a single separate report. 
Unless the facility qualifies for an exemption under Sec.  60.700a(c), 
the facility must begin compliance with the requirements set forth in 
Sec.  60.702a.
    (8) Any change in equipment or process operation that increases the 
vent stream concentration above the low concentration exemption level 
in Sec.  60.700a(c)(7), including a measurement of the new vent stream 
concentration, as recorded under paragraph (j) of this section. These 
must be reported as soon as possible after the change and no later than 
180 days after the change. These reports may be submitted either in 
conjunction with semiannual reports or as a single separate report. The 
performance test is subject to the requirements of Sec.  60.8 and must 
be submitted according to paragraph (b)(1) of this section. Unless the 
facility qualifies for an exemption under Sec.  60.700a(c), the 
facility must begin compliance with the requirements set forth in Sec.  
60.702a.
    (9) Exceedances of the emission standard in table 1 of this subpart 
as indicated by a 3-hour average of the TOC CEMS and recorded under 
paragraph (c) of this section. For each exceedance, the report must 
include a list of the affected facilities or equipment, the start date 
and time of the exceedance, the duration (in hours) of the exceedance, 
an estimate of the quantity in pounds of each regulated pollutant 
emitted over the emission limit, a description of the method used to 
estimate the emissions, the cause of the exceedance (including unknown 
cause, if applicable), as applicable, and the corrective action taken.
    (10) Periods when the TOC CEMS was inoperative. For each period, 
the report must include a list of the affected facilities or equipment, 
the start date and time of the period, the duration (in hours) of the 
period, the cause of the inoperability (including unknown cause, if 
applicable), as applicable, and the corrective action taken.
    (l) If you are required to submit notifications or reports 
following the procedure specified in this paragraph (l), you must 
submit notifications or reports to the EPA via CEDRI, which can be 
accessed through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/). The EPA will make all the information submitted through 
CEDRI available to the public without further notice to you. Do not use 
CEDRI to submit information you claim as CBI. Although we do not expect 
persons to assert a claim of CBI, if you wish to assert a CBI claim for 
some of the information in the report or notification, you must submit 
a complete file in the format specified in this subpart, including 
information claimed to be CBI, to the EPA following the procedures in 
paragraphs (l)(1) and (2) of this section. Clearly mark the part or all 
of the information that you claim to be CBI. Information not marked as 
CBI may be authorized for public release without prior notice. 
Information marked as CBI will not be disclosed except in accordance 
with procedures set forth in 40 CFR part 2. All CBI claims must be 
asserted at the time of submission. Anything submitted using CEDRI 
cannot later be claimed CBI. Furthermore, under CAA section 114(c), 
emissions data is not entitled to confidential treatment, and the EPA 
is required to make emissions data available to the public. Thus, 
emissions data will not be protected as CBI and will be made publicly 
available. You must submit the same file submitted to the CBI office 
with the CBI omitted to the EPA via the EPA's CDX as described earlier 
in this paragraph (l).
    (1) The preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
[email protected], and as described above, should include clear CBI 
markings. ERT files should be flagged to the attention of the Group 
Leader, Measurement Policy Group; all other files should be flagged to 
the attention of the SOCMI NSPS Sector Lead. If assistance is needed 
with submitting large electronic files that exceed the file size limit 
for email attachments, and if you do not have your own file sharing 
service, please email [email protected] to request a file transfer link.
    (2) If you cannot transmit the file electronically, you may send 
CBI information through the postal service to the following address: 
OAQPS Document Control Officer (C404-02), OAQPS, U.S. Environmental 
Protection Agency, 109 T.W. Alexander Drive, P.O. Box 12055, Research 
Triangle Park, North Carolina 27711. ERT files should be sent to the 
attention of the Group Leader, Measurement Policy Group, and all other 
files should be sent to the attention of the SOCMI NSPS Sector Lead. 
The mailed CBI material should be double wrapped and clearly marked. 
Any CBI markings should not show through the outer envelope.
    (m) If you are required to electronically submit notifications or 
reports through CEDRI in the EPA's CDX, you may assert a claim of EPA 
system outage for failure to timely comply with the electronic 
submittal requirement. To assert a claim of EPA system outage, you must 
meet the requirements outlined in paragraphs (m)(1) through (7) of this 
section.
    (1) You must have been or will be precluded from accessing CEDRI 
and submitting a required report within the time prescribed due to an 
outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (5) You must provide to the Administrator a written description 
identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;

[[Page 43141]]

    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (n) If you are required to electronically submit notifications or 
reports through CEDRI in the EPA's CDX, you may assert a claim of force 
majeure for failure to timely comply with the electronic submittal 
requirement. To assert a claim of force majeure, you must meet the 
requirements outlined in paragraphs (n)(1) through (5) of this section.
    (1) You may submit a claim if a force majeure event is about to 
occur, occurs, or has occurred or there are lingering effects from such 
an event within the period of time beginning five business days prior 
to the date the submission is due. For the purposes of this section, a 
force majeure event is defined as an event that will be or has been 
caused by circumstances beyond the control of the affected facility, 
its contractors, or any entity controlled by the affected facility that 
prevents you from complying with the requirement to submit a report 
electronically within the time period prescribed. Examples of such 
events are acts of nature (e.g., hurricanes, earthquakes, or floods), 
acts of war or terrorism, or equipment failure or safety hazard beyond 
the control of the affected facility (e.g., large scale power outage).
    (2) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (3) You must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.
    (o) The requirements of paragraph (k) of this section remain in 
force until and unless EPA, in delegating enforcement authority to a 
State under section 111(c) of the Act, approves reporting requirements 
or an alternative means of compliance surveillance adopted by such 
State. In that event, affected sources within the State will be 
relieved of the obligation to comply with paragraph (k) of this 
section, provided that they comply with the requirements established by 
the State. The EPA will not approve a waiver of electronic reporting to 
the EPA in delegating enforcement authority. Thus, electronic reporting 
to the EPA cannot be waived, and as such, the provisions of this 
paragraph cannot be used to relieve owners or operators of affected 
facilities of the requirement to submit the electronic reports required 
in this section to the EPA.
    (p) If you seek to demonstrate compliance with Sec.  60.700a(c)(2), 
then you must submit to the Administrator an initial report detailing 
the design production capacity of the process unit.
    (q) If you seek to demonstrate compliance with Sec.  60.700a(c)(3), 
then you must submit to the Administrator an initial report including a 
flow rate measurement using the test methods specified in Sec.  
60.704a.
    (r) If you seek to demonstrate compliance with Sec.  60.700a(c)(4), 
then you must submit to the Administrator a process design description 
as part of the initial report. This process design description must be 
retained for the life of the process. No other records or reports would 
be required unless process changes are made.
    (s) If you seek to demonstrate compliance with Sec.  60.700a(c)(7), 
then you must submit to the Administrator an initial report including a 
concentration measurement using the test method specified in Sec.  
60.704a.
    (t) The Administrator will specify appropriate reporting and 
recordkeeping requirements where the owner or operator of an affected 
facility complies with the standards specified under Sec.  60.702a 
other than as provided under Sec.  60.703a.
    (u) If you seek to demonstrate compliance with Sec.  60.702a using 
a control device, then you must maintain on file a schematic diagram of 
the affected vent streams, collection system(s), fuel systems, control 
devices, and bypass systems as part of the initial report. This 
schematic diagram must be retained for the life of the system.
    (v) Any records required to be maintained by this subpart that are 
submitted electronically via the EPA's CEDRI may be maintained in 
electronic format. This ability to maintain electronic copies does not 
affect the requirement for facilities to make records, data, and 
reports available upon request to a delegated air agency or the EPA as 
part of an on-site compliance evaluation.


Sec.  60.706a  What do the terms associated with reconstruction mean 
for this subpart?

    For purposes of this subpart ``fixed capital cost of the new 
components,'' as used in Sec.  60.15, includes the fixed capital cost 
of all depreciable components which are or will be replaced pursuant to 
all continuous programs of component replacement which are commenced 
within any 2-year period following April 25, 2023. For purposes of this 
paragraph, ``commenced'' means that you have undertaken a continuous 
program of component replacement or that you have entered into a 
contractual obligation to undertake and complete, within a reasonable 
time, a continuous program of component replacement.


Sec.  60.707a  What are the chemicals that I must produce to be 
affected by subpart RRRa?

------------------------------------------------------------------------
                       Chemical                            CAS No.\1\
------------------------------------------------------------------------
Acetaldehyde.........................................            75-07-0
Acetic acid..........................................            64-19-7
Acetic anhydride.....................................           108-24-7
Acetone..............................................            67-64-1
Acetone cyanohydrin..................................            75-86-5
Acetylene............................................            74-86-2

[[Page 43142]]

 
Acrylic acid.........................................            79-10-7
Acrylonitrile........................................           107-13-1
Adipic acid..........................................           124-04-9
Adiponitrile.........................................           111-69-3
Alcohols, C-11 or lower, mixtures....................
Alcohols, C-12 or higher, mixtures...................
Alcohols, C-12 or higher, unmixed....................
Allyl chloride.......................................           107-05-1
Amylene..............................................           513-35-9
Amylenes, mixed......................................
Aniline..............................................            62-53-3
Benzene..............................................            71-43-2
Benzenesulfonic acid.................................            98-11-3
Benzenesulfonic acid C10-16-alkyl derivatives, sodium         68081-81-2
 salts...............................................
Benzyl chloride......................................           100-44-7
Bisphenol A..........................................            80-05-7
Brometone............................................            76-08-4
1,3-Butadiene........................................           106-99-0
Butadiene and butene fractions.......................
n-Butane.............................................           106-97-8
1,4-Butanediol.......................................           110-63-4
Butanes, mixed.......................................
1-Butene.............................................           106-98-9
2-Butene.............................................         25167-67-3
Butenes, mixed.......................................
n-Butyl acetate......................................           123-86-4
Butyl acrylate.......................................           141-32-2
n-Butyl alcohol......................................            71-36-3
sec-Butyl alcohol....................................            78-92-2
tert-Butyl alcohol...................................            75-65-0
Butylbenzyl phthalate................................            85-68-7
tert-Butyl hydroperoxide.............................            75-91-2
2-Butyne-1,4-diol....................................           110-65-6
Butyraldehyde........................................           123-72-8
Butyric anhydride....................................           106-31-0
Caprolactam..........................................           105-60-2
Carbon disulfide.....................................            75-15-0
Carbon tetrachloride.................................            56-23-5
Chloroacetic acid....................................            79-11-8
Chlorobenzene........................................           108-90-7
Chlorodifluoromethane................................            75-45-6
Chloroform...........................................            67-66-3
p-Chloronitrobenzene.................................           100-00-5
Citric acid..........................................            77-92-9
Cumene...............................................            98-82-8
Cumene hydroperoxide.................................            80-15-9
Cyanuric chloride....................................           108-77-0
Cyclohexane..........................................           110-82-7
Cyclohexane, oxidized................................         68512-15-2
Cyclohexanol.........................................           108-93-0
Cyclohexanone........................................           108-94-1
Cyclohexanone oxime..................................           100-64-1
Cyclohexene..........................................           110-83-8
Cyclopropane.........................................            75-19-4
Diacetone alcohol....................................           123-42-2
1,4-Dichlorobutene...................................           110-57-6
3,4-Dichloro-1-butene................................         64037-54-3
Dichlorodifluoromethane..............................            75-71-8
Dichlorodimethylsilane...............................            75-78-5
Dichlorofluoromethane................................            75-43-4
Diethanolamine.......................................           111-42-2
Diethylbenzene.......................................         25340-17-4
Diethylene glycol....................................           111-46-6
Di-isodecyl phthalate................................         26761-40-0
Dimethyl terephthalate...............................           120-61-6
2,4-(and 2,6)-dinitrotoluene.........................           121-14-2
                                                                606-20-2
Dioctyl phthalate....................................           117-81-7
Dodecene.............................................         25378-22-7
Dodecylbenzene, nonlinear............................
Dodecylbenzenesulfonic acid..........................         27176-87-0
Dodecylbenzenesulfonic acid, sodium salt.............         25155-30-0
Epichlorohydrin......................................           106-89-8
Ethanol..............................................            64-17-5

[[Page 43143]]

 
Ethanolamine.........................................           141-43-5
Ethyl acetate........................................           141-78-6
Ethyl acrylate.......................................           140-88-5
Ethylbenzene.........................................           100-41-4
Ethyl chloride.......................................            75-00-3
Ethylene.............................................            74-85-1
Ethylene dibromide...................................           106-93-4
Ethylene dichloride..................................           107-06-2
Ethylene glycol......................................           107-21-1
Ethylene glycol monobutyl ether......................           111-76-2
Ethylene glycol monoethyl ether acetate..............           111-15-9
Ethylene glycol monomethyl ether.....................           109-86-4
Ethylene oxide.......................................            75-21-8
2-Ethylhexyl alcohol.................................           104-76-7
(2-Ethylhexyl) amine.................................           104-75-6
6-Ethyl-1,2,3,4-tetrahydro 9,10-anthracenedione......         15547-17-8
Formaldehyde.........................................            50-00-0
Glycerol.............................................            56-81-5
n-Heptane............................................           142-82-5
Heptenes (mixed).....................................
Hexamethylene diamine................................           124-09-4
Hexamethylene diamine adipate........................          3323-53-3
Hexamethylenetetramine...............................           100-97-0
Hexane...............................................           110-54-3
Isobutane............................................            75-28-5
Isobutanol...........................................            78-83-1
Isobutylene..........................................           115-11-7
Isobutyraldehyde.....................................            78-84-2
Isopentane...........................................            78-78-4
Isoprene.............................................            78-79-5
Isopropanol..........................................            67-63-0
Ketene...............................................           463-51-4
Linear alcohols, ethoxylated, mixed..................
Linear alcohols, ethoxylated, and sulfated, sodium
 salt, mixed.........................................
Linear alcohols, sulfated, sodium salt, mixed........
Linear alkylbenzene..................................           123-01-3
Maleic anhydride.....................................           108-31-6
Mesityl oxide........................................           141-79-7
Methanol.............................................            67-56-1
Methylamine..........................................            74-39-5
ar-Methylbenzenediamine..............................         25376-45-8
Methyl chloride......................................            74-87-3
Methylene chloride...................................            75-09-2
Methyl ethyl ketone..................................            78-93-3
Methyl isobutyl ketone...............................           108-10-1
Methyl methacrylate..................................            80-62-6
1-Methyl-2-pyrrolidone...............................           872-50-4
Methyl tert-butyl ether..............................
Naphthalene..........................................            91-20-3
Nitrobenzene.........................................            98-95-3
1-Nonene.............................................         27215-95-8
Nonyl alcohol........................................           143-08-8
Nonylphenol..........................................         25154-52-3
Nonylphenol, ethoxylated.............................          9016-45-9
Octene...............................................         25377-83-7
Oil-soluble petroleum sulfonate, calcium salt........
Pentaerythritol......................................           115-77-5
3-Pentenenitrile.....................................          4635-87-4
Pentenes, mixed......................................           109-67-1
Perchloroethylene....................................           127-18-4
Phenol...............................................           108-95-2
1-Phenylethyl hydroperoxide..........................          3071-32-7
Phenylpropane........................................           103-65-1
Phosgene.............................................            75-44-5
Phthalic anhydride...................................            85-44-9
Propane..............................................            74-98-6
Propionaldehyde......................................           123-38-6
Propyl alcohol.......................................            71-23-8
Propylene............................................           115-07-1
Propylene glycol.....................................            57-55-6
Propylene oxide......................................            75-56-9
Sorbitol.............................................            50-70-4
Styrene..............................................           100-42-5
Terephthalic acid....................................           100-21-0

[[Page 43144]]

 
Tetraethyl lead......................................            78-00-2
Tetrahydrofuran......................................           109-99-9
Tetra (methyl-ethyl) lead............................
Tetramethyl lead.....................................            75-74-1
Toluene..............................................           108-88-3
Toluene-2,4-diamine..................................            95-80-7
Toluene-2,4-(and, 2,6)-diisocyanate (80/20 mixture)..         26471-62-5
1,1,1-Trichloroethane................................            71-55-6
1,1,2-Trichloroethane................................            79-00-5
Trichloroethylene....................................            79-01-6
Trichlorofluoromethane...............................            75-69-4
1,1,2-Trichloro-1,2,2-trifluoroethane................            76-13-1
Triethanolamine......................................           102-71-6
Triethylene glycol...................................           112-27-6
Vinyl acetate........................................           108-05-4
Vinyl chloride.......................................            75-01-4
Vinylidene chloride..................................            75-35-4
m-Xylene.............................................           108-38-3
o-Xylene.............................................            95-47-6
p-Xylene.............................................           106-42-3
Xylenes (mixed)......................................          1330-20-7
------------------------------------------------------------------------
\1\ CAS numbers refer to the Chemical Abstracts Registry numbers
  assigned to specific chemicals, isomers, or mixtures of chemicals.
  Some isomers or mixtures that are covered by the standards do not have
  CAS numbers assigned to them. The standards apply to all of the
  chemicals listed, whether CAS numbers have been assigned or not.

Sec.  60.708a  [Reserved]


Sec.  60.709a  What are my requirements if I use a flare to comply with 
this subpart?

    (a) If you use a flare to comply with the TOC emission standard 
specified in table 1 to this subpart, then you must meet the applicable 
requirements for flares as specified in Sec. Sec.  63.670 and 63.671 of 
this chapter, including the provisions in tables 12 and 13 to part 63, 
subpart CC, of this chapter, except as specified in paragraphs (b) 
through (o) of this section. This requirement also applies to any flare 
using fuel gas from a fuel gas system, of which 50 percent or more of 
the fuel gas is derived from an affected facility, as determined on an 
annual average basis. For purposes of compliance with this paragraph 
(a), the following terms are defined in Sec.  63.641 of this chapter: 
Assist air, assist steam, center steam, combustion zone, combustion 
zone gas, flare, flare purge gas, flare supplemental gas, flare sweep 
gas, flare vent gas, lower steam, net heating value, perimeter assist 
air, pilot gas, premix assist air, total steam, and upper steam.
    (b) When determining compliance with the pilot flame requirements 
specified in Sec.  63.670(b) and (g) of this chapter, substitute 
``pilot flame or flare flame'' for each occurrence of ``pilot flame.''
    (c) When determining compliance with the flare tip velocity and 
combustion zone operating limits specified in Sec.  63.670(d) and (e) 
of this chapter, the requirement effectively applies starting with the 
15-minute block that includes a full 15 minutes of the flaring event. 
You are required to demonstrate compliance with the velocity and NHVcz 
requirements starting with the block that contains the fifteenth minute 
of a flaring event. You are not required to demonstrate compliance for 
the previous 15-minute block in which the event started and contained 
only a fraction of flow.
    (d) Instead of complying with Sec.  63.670(o)(2)(i) of this 
chapter, you must develop and implement the flare management plan no 
later than startup for a new flare that commenced construction on or 
after April 25, 2023.
    (e) Instead of complying with Sec.  63.670(o)(2)(iii) of this 
chapter, if required to develop a flare management plan and submit it 
to the Administrator, then you must also submit all versions of the 
plan in portable document format (PDF) following the procedures 
specified in Sec.  60.705a(l).
    (f) Section 63.670(o)(3)(ii) of this chapter and all references to 
it do not apply. Instead, you must comply with the maximum flare tip 
velocity operating limit at all times.
    (g) Substitute ``affected facility'' for each occurrence of 
``petroleum refinery.''
    (h) Each occurrence of ``refinery'' does not apply.
    (i) If a pressure-assisted multi-point flare is used as a control 
device, then you must meet the following conditions:
    (1) You are not required to comply with the flare tip velocity 
requirements in Sec.  63.670(d) and (k) of this chapter;
    (2) The NHVcz for pressure-assisted mulit-point flares is 800 Btu/
scf;
    (3) You must determine the 15-minute block average NHVvg using only 
the direct calculation method specified in Sec.  63.670(l)(5)(ii) of 
this chapter;
    (4) Instead of complying with Sec.  63.670(b) and (g) of this 
chapter, if a pressure-assisted multi-point flare uses cross-lighting 
on a stage of burners rather than having an individual pilot flame on 
each burner, then you must operate each stage of the pressure-assisted 
multi-point flare with a flame present at all times when regulated 
material is routed to that stage of burners. Each stage of burners that 
cross-lights in the pressure-assisted multi-point flare must have at 
least two pilots with at least one continuously lit and capable of 
igniting all regulated material that is routed to that stage of 
burners. Each 15-minute block during which there is at least one minute 
where no pilot flame is present on a stage of burners when regulated 
material is routed to the flare is a deviation of the standard. 
Deviations in different 15-minute blocks from the same event are 
considered separate deviations. The pilot flame(s) on each stage of 
burners that use cross-lighting must be continuously monitored by a 
thermocouple or any other equivalent device used to detect the presence 
of a flame;
    (5) Unless you choose to conduct a cross-light performance 
demonstration as specified in this paragraph (i)(5), you must ensure 
that if a stage of burners on the flare uses cross-lighting, that the 
distance between any two burners in series on that stage is no more 
than 6 feet when measured from the center of one burner to the next 
burner. A distance greater than 6 feet between any two burners in 
series may be used

[[Page 43145]]

provided you conduct a performance demonstration that confirms the 
pressure-assisted multi-point flare will cross-light a minimum of three 
burners and the spacing between the burners and location of the pilot 
flame must be representative of the projected installation. The 
compliance demonstration must be approved by the permitting authority 
and a copy of this approval must be maintained onsite. The compliance 
demonstration report must include: a protocol describing the test 
methodology used, associated test method QA/QC parameters, the waste 
gas composition and NHVcz of the gas tested, the velocity of the waste 
gas tested, the pressure-assisted multi-point flare burner tip 
pressure, the time, length, and duration of the test, records of 
whether a successful cross-light was observed over all of the burners 
and the length of time it took for the burners to cross-light, records 
of maintaining a stable flame after a successful cross-light and the 
duration for which this was observed, records of any smoking events 
during the cross-light, waste gas temperature, meteorological 
conditions (e.g., ambient temperature, barometric pressure, wind speed 
and direction, and relative humidity), and whether there were any 
observed flare flameouts; and
    (6) You must install and operate pressure monitor(s) on the main 
flare header, as well as a valve position indicator monitoring system 
for each staging valve to ensure that the flare operates within the 
proper range of conditions as specified by the manufacturer. The 
pressure monitor must meet the requirements in Table 13 to part 63, 
subpart CC of this chapter.
    (7) If a pressure-assisted multi-point flare is operating under the 
requirements of an approved alternative means of emission limitations, 
you must either continue to comply with the terms of the alternative 
means of emission limitations or comply with the provisions in 
paragraphs (i)(1) through (6) of this section.
    (j) If you choose to determine compositional analysis for net 
heating value with a continuous process mass spectrometer, then you 
must comply with the requirements specified in paragraphs (j)(1) 
through (7) of this section.
    (1) You must meet the requirements in Sec.  63.671(e)(2) of this 
chapter. You may augment the minimum list of calibration gas components 
found in Sec.  63.671(e)(2) of this chapter with compounds found during 
a pre-survey or known to be in the gas through process knowledge.
    (2) Calibration gas cylinders must be certified to an accuracy of 2 
percent and traceable to National Institute of Standards and Technology 
(NIST) standards.
    (3) For unknown gas components that have similar analytical mass 
fragments to calibration compounds, you may report the unknowns as an 
increase in the overlapped calibration gas compound. For unknown 
compounds that produce mass fragments that do not overlap calibration 
compounds, you may use the response factor for the nearest molecular 
weight hydrocarbon in the calibration mix to quantify the unknown 
component's NHVvg.
    (4) You may use the response factor for n-pentane to quantify any 
unknown components detected with a higher molecular weight than n-
pentane.
    (5) You must perform an initial calibration to identify mass 
fragment overlap and response factors for the target compounds.
    (6) You must meet applicable requirements in Performance 
Specification 9 of appendix B of this part, for continuous monitoring 
system acceptance including, but not limited to, performing an initial 
multi-point calibration check at three concentrations following the 
procedure in section 10.1 and performing the periodic calibration 
requirements listed for gas chromatographs in table 13 to part 63, 
subpart CC, of this chapter, for the process mass spectrometer. You may 
use the alternative sampling line temperature allowed under Net Heating 
Value by Gas Chromatograph in table 13 to part 63, subpart CC, of this 
chapter.
    (7) The average instrument calibration error (CE) for each 
calibration compound at any calibration concentration must not differ 
by more than 10 percent from the certified cylinder gas value. The CE 
for each component in the calibration blend must be calculated using 
Equation 1 to this paragraph (j)(7).

Equation 1 to Paragraph (j)(7)
[GRAPHIC] [TIFF OMITTED] TR16MY24.051

Where:

Cm = Average instrument response (ppm)
Ca = Certified cylinder gas value (ppm)

    (k) If you use a gas chromatograph or mass spectrometer for 
compositional analysis for net heating value, then you may choose to 
use the CE of NHVmeasured versus the cylinder tag value NHV 
as the measure of agreement for daily calibration and quarterly audits 
in lieu of determining the compound-specific CE. The CE for NHV at any 
calibration level must not differ by more than 10 percent from the 
certified cylinder gas value. The CE must be calculated using equation 
2 to this paragraph (k).

Equation 2 to Paragraph (k)
[GRAPHIC] [TIFF OMITTED] TR16MY24.052

Where:

NHVmeasured = Average instrument response (Btu/scf)
NHVa = Certified cylinder gas value (Btu/scf)

    (l) Instead of complying with paragraph (q) of Sec.  63.670 of this 
chapter, you must comply with the reporting requirements specified in 
paragraphs (l)(1) and (2) of this section.
    (1) The notification requirements specified in Sec.  60.705a(a).
    (2) The semiannual report specified in Sec.  60.705a(k)(4) must 
include the items specified in paragraphs (l)(2)(i) through (vi) of 
this section.
    (i) Records as specified in paragraph (m)(1) of this section for 
each 15-minute block during which there was at least one minute when 
regulated material is routed to a flare and no pilot flame or flare 
flame is present. Include the start and stop time and date of each 15-
minute block.
    (ii) Visible emission records as specified in paragraph (m)(2)(iv) 
of this section for each period of 2 consecutive hours during which 
visible emissions exceeded a total of 5 minutes.
    (iii) The periods specified in paragraph (m)(6) of this section. 
Indicate the date and start and end times for each

[[Page 43146]]

period, and the net heating value operating parameter(s) determined 
following the methods in Sec.  63.670(k) through (n) of part 63, 
subpart CC of this chapter as applicable.
    (iv) For flaring events meeting the criteria in Sec.  63.670(o)(3) 
of this chapter and paragraph (f) of this section:
    (A) The start and stop time and date of the flaring event.
    (B) The length of time in minutes for which emissions were visible 
from the flare during the event.
    (C) For steam-assisted, air-assisted, and non-assisted flares, the 
start date, start time, and duration in minutes for periods of time 
that the flare tip velocity exceeds the maximum flare tip velocity 
determined using the methods in Sec.  63.670(d)(2) of this chapter and 
the maximum 15-minute block average flare tip velocity in ft/sec 
recorded during the event.
    (D) Results of the root cause and corrective actions analysis 
completed during the reporting period, including the corrective actions 
implemented during the reporting period and, if applicable, the 
implementation schedule for planned corrective actions to be 
implemented subsequent to the reporting period.
    (v) For pressure-assisted multi-point flares, the periods of time 
when the pressure monitor(s) on the main flare header show the burners 
operating outside the range of the manufacturer's specifications. 
Indicate the date and start and end times for each period.
    (vi) For pressure-assisted multi-point flares, the periods of time 
when the staging valve position indicator monitoring system indicates a 
stage should not be in operation and is or when a stage should be in 
operation and is not. Indicate the date and start and end times for 
each period.
    (m) Instead of complying with Sec.  63.670(p) of this chapter, you 
must keep the flare monitoring records specified in paragraphs (m)(1) 
through (14) of this section.
    (1) Retain records of the output of the monitoring device used to 
detect the presence of a pilot flame or flare flame as required in 
Sec.  63.670(b) of this chapter and the presence of a pilot flame as 
required in paragraph (i)(4) of this section for a minimum of 2 years. 
Retain records of each 15-minute block during which there was at least 
one minute that no pilot flame or flare flame is present when regulated 
material is routed to a flare for a minimum of 5 years. For a pressure-
assisted multi-point flare that uses cross-lighting, retain records of 
each 15-minute block during which there was at least one minute that no 
pilot flame is present on each stage when regulated material is routed 
to a flare for a minimum of 5 years. You may reduce the collected 
minute-by-minute data to a 15-minute block basis with an indication of 
whether there was at least one minute where no pilot flame or flare 
flame was present.
    (2) Retain records of daily visible emissions observations as 
specified in paragraphs (m)(2)(i) through (iv) of this section, as 
applicable, for a minimum of 3 years.
    (i) To determine when visible emissions observations are required, 
the record must identify all periods when regulated material is vented 
to the flare.
    (ii) If visible emissions observations are performed using Method 
22 of appendix A-7 of this part, then the record must identify whether 
the visible emissions observation was performed, the results of each 
observation, total duration of observed visible emissions, and whether 
it was a 5-minute or 2-hour observation. Record the date and start time 
of each visible emissions observation.
    (iii) If a video surveillance camera is used pursuant to Sec.  
63.670(h)(2) of this chapter, then the record must include all video 
surveillance images recorded, with time and date stamps.
    (iv) For each 2-hour period for which visible emissions are 
observed for more than 5 minutes in 2 consecutive hours, then the 
record must include the date and start and end time of the 2-hour 
period and an estimate of the cumulative number of minutes in the 2-
hour period for which emissions were visible.
    (3) The 15-minute block average cumulative flows for flare vent gas 
and, if applicable, total steam, perimeter assist air, and premix 
assist air specified to be monitored under Sec.  63.670(i) of this 
chapter, along with the date and time interval for the 15-minute block. 
If multiple monitoring locations are used to determine cumulative vent 
gas flow, total steam, perimeter assist air, and premix assist air, 
then retain records of the 15-minute block average flows for each 
monitoring location for a minimum of 2 years and retain the 15-minute 
block average cumulative flows that are used in subsequent calculations 
for a minimum of 5 years. If pressure and temperature monitoring is 
used, then retain records of the 15-minute block average temperature, 
pressure, and molecular weight of the flare vent gas or assist gas 
stream for each measurement location used to determine the 15-minute 
block average cumulative flows for a minimum of 2 years, and retain the 
15-minute block average cumulative flows that are used in subsequent 
calculations for a minimum of 5 years.
    (4) The flare vent gas compositions specified to be monitored under 
Sec.  63.670(j) of this chapter. Retain records of individual component 
concentrations from each compositional analysis for a minimum of 2 
years. If an NHVvg analyzer is used, retain records of the 15-minute 
block average values for a minimum of 5 years.
    (5) Each 15-minute block average operating parameter calculated 
following the methods specified in Sec.  63.670(k) through (n) of this 
chapter, as applicable.
    (6) All periods during which operating values are outside of the 
applicable operating limits specified in Sec.  63.670(d) through (f) of 
this chapter and paragraph (i) of this section when regulated material 
is being routed to the flare.
    (7) All periods during which you do not perform flare monitoring 
according to the procedures in Sec.  63.670(g) through (j) of this 
chapter.
    (8) For pressure-assisted multi-point flares, if a stage of burners 
on the flare uses cross-lighting, then a record of any changes made to 
the distance between burners.
    (9) For pressure-assisted multi-point flares, all periods when the 
pressure monitor(s) on the main flare header show burners are operating 
outside the range of the manufacturer's specifications. Indicate the 
date and time for each period, the pressure measurement, the stage(s) 
and number of burners affected, and the range of manufacturer's 
specifications.
    (10) For pressure-assisted multi-point flares, all periods when the 
staging valve position indicator monitoring system indicates a stage of 
the pressure-assisted multi-point flare should not be in operation and 
when a stage of the pressure-assisted multi-point flare should be in 
operation and is not. Indicate the date and time for each period, 
whether the stage was supposed to be open, but was closed or vice 
versa, and the stage(s) and number of burners affected.
    (11) Records of periods when there is flow of vent gas to the 
flare, but when there is no flow of regulated material to the flare, 
including the start and stop time and dates of periods of no regulated 
material flow.
    (12) Records when the flow of vent gas exceeds the smokeless 
capacity of the flare, including start and stop time and dates of the 
flaring event.
    (13) Records of the root cause analysis and corrective action 
analysis conducted as required in Sec.  63.670(o)(3) of this chapter 
and paragraph (f) of this section, including an identification of the 
affected flare, the date and duration

[[Page 43147]]

of the event, a statement noting whether the event resulted from the 
same root cause(s) identified in a previous analysis and either a 
description of the recommended corrective action(s) or an explanation 
of why corrective action is not necessary under Sec.  63.670(o)(5)(i) 
of this chapter.
    (14) For any corrective action analysis for which implementation of 
corrective actions are required in Sec.  63.670(o)(5) of this chapter, 
a description of the corrective action(s) completed within the first 45 
days following the discharge and, for action(s) not already completed, 
a schedule for implementation, including proposed commencement and 
completion dates.
    (n) You may elect to comply with the alternative means of emissions 
limitation requirements specified in Sec.  63.670(r) of this chapter in 
lieu of the requirements in Sec.  63.670(d) through (f) of this 
chapter, as applicable. However, instead of complying with Sec.  
63.670(r)(3)(iii) of this chapter, you must also submit the alternative 
means of emissions limitation request to the following address: U.S. 
Environmental Protection Agency, Office of Air Quality Planning and 
Standards, Sector Policies and Programs Division, U.S. EPA Mailroom 
(C404-02), Attention: SOCMI NSPS Sector Lead, 4930 Old Page Rd., 
Durham, NC 27703.
    (o) The referenced provisions specified in paragraphs (o)(1) 
through (4) of this section do not apply when demonstrating compliance 
with this section.
    (1) Section 63.670(o)(4)(iv) of this chapter.
    (2) The last sentence of Sec.  63.670(o)(6) of this chapter.
    (3) The phrase ``that were not caused by a force majeure event'' in 
Sec.  63.670(o)(7)(ii) of this chapter.
    (4) The phrase ``that were not caused by a force majeure event'' in 
Sec.  63.670(o)(7)(iv) of this chapter.


Sec.  60.710a  What are my requirements for closed vent systems?

    (a) Except as provided in paragraphs (f) and (g) of this section, 
you must inspect each closed vent system according to the procedures 
and schedule specified in paragraphs (a)(1) through (3) of this 
section.
    (1) Conduct an initial inspection according to the procedures in 
paragraph (b) of this section unless the closed vent system is operated 
and maintained under negative pressure,
    (2) Conduct annual inspections according to the procedures in 
paragraph (b) of this section unless the closed vent system is operated 
and maintained under negative pressure, and
    (3) Conduct annual inspections for visible, audible, or olfactory 
indications of leaks.
    (b) You must inspect each closed vent system according to the 
procedures specified in paragraphs (b)(1) through (6) of this section.
    (1) Inspections must be conducted in accordance with Method 21 of 
appendix A of this part.
    (2)(i) Except as provided in paragraph (b)(2)(ii) of this section, 
the detection instrument must meet the performance criteria of Method 
21 of appendix A of this part, except the instrument response factor 
criteria in section 3.1.2(a) of Method 21 must be for the average 
composition of the process fluid not each individual volatile organic 
compound in the stream. For process streams that contain nitrogen, air, 
or other inerts which are not organic hazardous air pollutants or 
volatile organic compounds, the average stream response factor must be 
calculated on an inert-free basis.
    (ii) If no instrument is available at the plant site that will meet 
the performance criteria specified in paragraph (b)(2)(i) of this 
section, the instrument readings may be adjusted by multiplying by the 
average response factor of the process fluid, calculated on an inert-
free basis as described in paragraph (b)(2)(i) of this section.
    (3) The detection instrument must be calibrated before use on each 
day of its use by the procedures specified in Method 21 of appendix A 
of this part.
    (4) Calibration gases must be as follows:
    (i) Zero air (less than 10 parts per million hydrocarbon in air); 
and
    (ii) Mixtures of methane in air at a concentration less than 2,000 
parts per million. A calibration gas other than methane in air may be 
used if the instrument does not respond to methane or if the instrument 
does not meet the performance criteria specified in paragraph (b)(2)(i) 
of this section. In such cases, the calibration gas may be a mixture of 
one or more of the compounds to be measured in air.
    (5) You may elect to adjust or not adjust instrument readings for 
background. If you elect to not adjust readings for background, all 
such instrument readings must be compared directly to the applicable 
leak definition to determine whether there is a leak.
    (6) If you elect to adjust instrument readings for background, you 
must determine the background concentration using Method 21 of appendix 
A of this part. After monitoring each potential leak interface, 
subtract the background reading from the maximum concentration 
indicated by the instrument. The arithmetic difference between the 
maximum concentration indicated by the instrument and the background 
level must be compared with 500 parts per million for determining 
compliance.
    (c) Leaks, as indicated by an instrument reading greater than 500 
parts per million above background or by visual, audio, or olfactory 
inspections, must be repaired as soon as practicable, except as 
provided in paragraph (d) of this section.
    (1) A first attempt at repair must be made no later than 5 calendar 
days after the leak is detected.
    (2) Repair must be completed no later than 15 calendar days after 
the leak is detected.
    (d) Delay of repair of a closed vent system for which leaks have 
been detected is allowed if the repair is technically infeasible 
without a shutdown, as defined in Sec.  60.2, or if you determine that 
emissions resulting from immediate repair would be greater than the 
fugitive emissions likely to result from delay of repair. Repair of 
such equipment must be complete by the end of the next shutdown.
    (e) For each closed vent system that contains bypass lines that 
could divert a vent stream away from the control device and to the 
atmosphere, you must comply with the provisions of either paragraph 
(e)(1) or (2), except as specified in paragraph (e)(3) of this section.
    (1) Install, calibrate, maintain, and operate a flow indicator that 
determines whether vent stream flow is present at least once every 15 
minutes. You must keep hourly records of whether the flow indicator was 
operating and whether a diversion was detected at any time during the 
hour, as well as records of the times and durations of all periods when 
the vent stream is diverted to the atmosphere or the flow indicator is 
not operating. The flow indicator must be installed at the entrance to 
any bypass line; or
    (2) Secure the bypass line valve in the closed position with a car-
seal or a lock-and-key type configuration. A visual inspection of the 
seal or closure mechanism must be performed at least once every month 
to ensure the valve is maintained in the closed position and the vent 
stream is not diverted through the bypass line.
    (3) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in Sec.  60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as

[[Page 43148]]

Sec.  60.482-6(a)(2), (b), and (c) are not subject to this paragraph 
(e) of this section.
    (f) Any parts of the closed vent system that are designated, as 
described in paragraph (h)(1) of this section, as unsafe to inspect are 
exempt from the inspection requirements of paragraphs (a)(1) and (2) of 
this section if:
    (1) You determine that the equipment is unsafe to inspect because 
inspecting personnel would be exposed to an imminent or potential 
danger as a consequence of complying with paragraphs (a)(1) and (2) of 
this section; and
    (2) You have a written plan that requires inspection of the 
equipment as frequently as practicable during safe-to-inspect times.
    (g) Any parts of the closed vent system are designated, as 
described in paragraph (h)(2) of this section, as difficult to inspect 
are exempt from the inspection requirements of paragraphs (a)(1) and 
(2) of this section if:
    (1) You determine that the equipment cannot be inspected without 
elevating the inspecting personnel more than 2 meters above a support 
surface; and
    (2) You have a written plan that requires inspection of the 
equipment at least once every 5 years.
    (h) You must record the information specified in paragraphs (h)(1) 
through (5) of this section.
    (1) Identification of all parts of the closed vent system that are 
designated as unsafe to inspect, an explanation of why the equipment is 
unsafe to inspect, and the plan for inspecting the equipment.
    (2) Identification of all parts of the closed vent system that are 
designated as difficult to inspect, an explanation of why the equipment 
is difficult to inspect, and the plan for inspecting the equipment.
    (3) For each closed vent system that contains bypass lines that 
could divert a vent stream away from the control device and to the 
atmosphere, you must keep a record of the information specified in 
either paragraph (h)(3)(i) or (ii) of this section in addition to the 
information specified in paragraph (h)(3)(iii) of this section.
    (i) Hourly records of whether the flow indicator specified under 
paragraph (e)(1) of this section was operating and whether a diversion 
was detected at any time during the hour, as well as records of the 
times of all periods when the vent stream is diverted from the control 
device or the flow indicator is not operating.
    (ii) Where a seal mechanism is used to comply with paragraph (e)(2) 
of this section, hourly records of flow are not required. In such 
cases, you must record whether the monthly visual inspection of the 
seals or closure mechanisms has been done, and you must record the 
occurrence of all periods when the seal mechanism is broken, the bypass 
line valve position has changed, or the key for a lock-and-key type 
configuration has been checked out, and records of any car-seal that 
has broken.
    (iii) For each flow event from a bypass line subject to the 
requirements in paragraph (e) of this section, you must maintain 
records sufficient to determine whether or not the detected flow 
included flow requiring control. For each flow event from a bypass line 
requiring control that is released either directly to the atmosphere or 
to a control device not meeting the requirements in this subpart, you 
must include an estimate of the volume of gas, the concentration of VOC 
in the gas and the resulting emissions of VOC that bypassed the control 
device using process knowledge and engineering estimates.
    (4) For each inspection during which a leak is detected, a record 
of the information specified in paragraphs (h)(4)(i) through (viii) of 
this section.
    (i) The instrument identification numbers; operator name or 
initials; and identification of the equipment.
    (ii) The date the leak was detected and the date of the first 
attempt to repair the leak.
    (iii) Maximum instrument reading measured by the method specified 
in paragraph (c) of this section after the leak is successfully 
repaired or determined to be nonrepairable.
    (iv) ``Repair delayed'' and the reason for the delay if a leak is 
not repaired within 15 calendar days after discovery of the leak.
    (v) The name, initials, or other form of identification of the 
owner or operator (or designee) whose decision it was that repair could 
not be effected without a shutdown.
    (vi) The expected date of successful repair of the leak if a leak 
is not repaired within 15 calendar days.
    (vii) Dates of shutdowns that occur while the equipment is 
unrepaired.
    (viii) The date of successful repair of the leak.
    (5) For each inspection conducted in accordance with paragraph (b) 
of this section during which no leaks are detected, a record that the 
inspection was performed, the date of the inspection, and a statement 
that no leaks were detected.
    (6) For each inspection conducted in accordance with paragraph 
(a)(3) of this section during which no leaks are detected, a record 
that the inspection was performed, the date of the inspection, and a 
statement that no leaks were detected.
    (i) The semiannual report specified in Sec.  60.705a(k)(5) must 
include the items specified in paragraphs (i)(1) through (3) of this 
section.
    (1) Reports of the times of all periods recorded under paragraph 
(h)(3)(i) of this section when the vent stream is diverted from the 
control device through a bypass line. Include the start date, start 
time, and duration in hours of each period.
    (2) Reports of all periods recorded under paragraph (h)(3)(ii) of 
this section in which the seal mechanism is broken, the bypass line 
valve position has changed, or the key to unlock the bypass line valve 
was checked out. Include the start date, start time, and duration in 
hours of each period.
    (3) For bypass lines subject to the requirements in paragraph (e) 
of this section, the semiannual reports must include the start date, 
start time, duration in hours, estimate of the volume of gas in 
standard cubic feet, the concentration of VOC in the gas in parts per 
million by volume and the resulting mass emissions of VOC in pounds 
that bypass a control device. For periods when the flow indicator is 
not operating, report the start date, start time, and duration in 
hours.

  Table 1 to Subpart RRRa of Part 60--Emission Limits and Standards for
                              Vent Streams
------------------------------------------------------------------------
           For each. . .                        You must. . .
------------------------------------------------------------------------
1. Vent stream....................  a. Reduce emissions of TOC (minus
                                     methane and ethane) by 98 weight-
                                     percent, or to a TOC (minus methane
                                     and ethane) concentration of 20
                                     ppmv on a dry basis corrected to 3
                                     percent oxygen by venting emissions
                                     through a closed vent system to any
                                     combination of non-flare control
                                     devices and/or recovery system and
                                     meet the requirements specified in
                                     Sec.   60.703a and Sec.   60.710a;
                                     or
                                    b. Reduce emissions of TOC (minus
                                     methane and ethane) by venting
                                     emissions through a closed vent
                                     system to a flare and meet the
                                     requirements specified in Sec.
                                     60.709a and Sec.   60.710a.
------------------------------------------------------------------------


[[Page 43149]]


     Table 2 to Subpart RRRa of Part 60--Monitoring Requirements for
  Complying With 98 Weight-Percent Reduction of Total Organic Compounds
         Emissions or a Limit of 20 Parts Per Million by Volume
------------------------------------------------------------------------
   Non-flare control device or
         recovery device                 Parameters to be monitored
------------------------------------------------------------------------
1. All control and recovery        a. Presence of flow diverted to the
 devices.                           atmosphere from the control and
                                    recovery device; or
                                   b. Monthly inspections of sealed
                                    valves
2. Absorber......................  a. Exit temperature of the absorbing
                                    liquid; and
                                   b. Exit specific gravity
3. Boiler or process heater with   Firebox temperature \a\
 a design heat input capacity
 less than 44 megawatts and vent
 stream is not introduced with or
 as the primary fuel.
4. Catalytic incinerator.........  Temperature upstream and downstream
                                    of the catalyst bed
5. Carbon adsorber, regenerative.  a. Total regeneration stream mass or
                                    volumetric flow during carbon bed
                                    regeneration cycle(s); and
                                   b. Temperature of the carbon bed
                                    after regeneration [and within 15
                                    minutes of completing any cooling
                                    cycle(s)]
6. Carbon adsorber, non-           Breakthrough
 regenerative or regenerated
 offsite.
7. Condenser.....................  Exit (product side) temperature
8. Scrubber for halogenated vent   a. pH of scrubber effluent;and
 streams.                          b. Scrubber liquid and gas flow rates
9. Thermal incinerator...........  Firebox temperature \a\
10. Control devices other than an  As specified by the Administrator
 incinerator, boiler, process
 heater, or flare; or recovery
 devices other than an absorber,
 condenser, or carbon adsorber.
------------------------------------------------------------------------
\a\ Monitor may be installed in the firebox or in the ductwork
  immediately downstream of the firebox before any substantial heat
  exchange is encountered.


    Table 3 to Subpart RRRa of Part 60--Operating Parameters, Operating Parameter Limits and Data Monitoring,
                                    Recordkeeping and Compliance Frequencies
----------------------------------------------------------------------------------------------------------------
                                      You must        And you must monitor, record, and demonstrate continuous
                                   establish the          compliance using these minimum frequencies . . .
  For the  operating parameter       following     -------------------------------------------------------------
applicable to you, as specified      operating                                                  Data  averaging
        in Table 2 . . .         parameter limit .     Data measurement      Data  recording       period for
                                        . .                                                        compliance
----------------------------------------------------------------------------------------------------------------
                                                    Absorbers
----------------------------------------------------------------------------------------------------------------
1. Exit temperature of the       Maximum            Continuous............  Every 15 minutes.  3-hour block
 absorbing liquid.                temperature.                                                  average
2. Exit specific gravity.......  Exit specific      Continuous............  Every 15 minutes.  3-hour block
                                  gravity range.                                                average
----------------------------------------------------------------------------------------------------------------
                                           Boilers or process heaters
     (with a design heat input capacity <44MW and vent stream is not introduced with or as the primary fuel)
----------------------------------------------------------------------------------------------------------------
3. Firebox temperature.........  Minimum firebox    Continuous............  Every 15 minutes.  3-hour block
                                  temperature.                                                  average
----------------------------------------------------------------------------------------------------------------
                                             Catalytic incinerators
----------------------------------------------------------------------------------------------------------------
4. Temperature in gas stream     Minimum            Continuous............  Every 15 minutes.  3-hour block
 immediately before the           temperature.                                                  average
 catalyst bed.
5. Temperature difference        Minimum            Continuous............  Every 15 minutes.  3-hour block
 between the catalyst bed inlet   temperature                                                   average
 and the catalyst bed outlet.     difference.
----------------------------------------------------------------------------------------------------------------
                                                Carbon adsorbers
----------------------------------------------------------------------------------------------------------------
6. Total regeneration stream     Minimum mass flow  Continuously during     Every 15 minutes   Total flow for
 mass flow during carbon bed      during carbon      regeneration.           during             each
 regeneration cycle(s).           bed regeneration                           regeneration       regeneration
                                  cycle(s).                                  cycle.             cycle

[[Page 43150]]

 
7. Total regeneration stream     Minimum            Continuously during     Every 15 minutes   Total flow for
 volumetric flow during carbon    volumetric flow    regeneration.           during             each
 bed regeneration cycle(s).       during carbon                              regeneration       regeneration
                                  bed regeneration                           cycle.             cycle
                                  cycle(s).
8. Temperature of the carbon     Maximum            Continuously during     Every 15 minutes   Average of
 bed after regeneration [and      temperature of     regeneration and for    during             regeneration
 within 15 minutes of             the carbon bed     15 minutes after        regeneration       cycle
 completing any cooling           after              completing any          cycle (including
 cycle(s)].                       regeneration.      cooling cycle(s).       any cooling
                                                                             cycle).
9. Breakthrough................  As defined in      As required by Sec.     Each monitoring    N/A
                                  Sec.   60.701a.    60.703a(a)(6)(iii)(B).  event.
----------------------------------------------------------------------------------------------------------------
                                                   Condensers
----------------------------------------------------------------------------------------------------------------
10. Exit (product side)          Maximum            Continuous............  Every 15 minutes.  3-hour block
 temperature.                     temperature.                                                  average
----------------------------------------------------------------------------------------------------------------
                                     Scrubbers for halogenated vent streams
----------------------------------------------------------------------------------------------------------------
11. pH of scrubber effluent....  Minimum pH.......  Continuous............  Every 15 minutes.  3-hour block
                                                                                                average
12. Influent liquid flow.......  Minimum inlet      Continuous............  Every 15 minutes.  3-hour block
                                  liquid flow.                                                  average
13. Influent liquid flow rate    Minimum influent   Continuous............  Every 15 minutes.  3-hour block
 and gas stream flow rate.        liquid-to-gas                                                 average
                                  ratio.
----------------------------------------------------------------------------------------------------------------
                                              Thermal incinerators
----------------------------------------------------------------------------------------------------------------
14. Firebox temperature........  Minimum firebox    Continuous............  Every 15 minutes.  3-hour block
                                  temperature.                                                  average
----------------------------------------------------------------------------------------------------------------
 Control devices other than an incinerator, boiler, process heater, or flare; or recovery devices other than an
                                     absorber, condenser, or carbon adsorber
----------------------------------------------------------------------------------------------------------------
15. As specified by the          As specified by    As specified by the     As specified by    As specified by
 Administrator.                   the                Administrator.          the                the
                                  Administrator.                             Administrator.     Administrator
----------------------------------------------------------------------------------------------------------------


   Table 4 to Subpart RRRa of Part 60--Calibration and Quality Control
     Requirements for Continuous Parameter Monitoring System (CPMS)
------------------------------------------------------------------------
                                                    And your calibration
     If you monitor this          Your accuracy     requirements are . .
       parameter . . .        requirements are . .            .
                                        .
------------------------------------------------------------------------
1. Temperature..............  a. 1      c. Performance
                               percent over the      evaluation annually
                               normal range of       and following any
                               temperature           period of more than
                               measured or 2.8       24 hours throughout
                               degrees Celsius (5    which the
                               degrees               temperature
                               Fahrenheit),          exceeded the
                               whichever is          maximum rated
                               greater, for non-     temperature of the
                               cryogenic             sensor, or the data
                               temperature ranges.   recorder was off
                              b. 2.5     scale.
                               percent over the     d. Visual
                               normal range of       inspections and
                               temperature           checks of CPMS
                               measured or 2.8       operation every 3
                               degrees Celsius (5    months, unless the
                               degrees               CPMS has a
                               Fahrenheit),          redundant
                               whichever is          temperature sensor.
                               greater, for         e. Selection of a
                               cryogenic             representative
                               temperature ranges.   measurement
                                                     location.

[[Page 43151]]

 
2. Flow Rate................  a. 5      d. Performance
                               percent over the      evaluation annually
                               normal range of       and following any
                               flow measured or      period of more than
                               1.9 liters per        24 hours throughout
                               minute (0.5 gallons   which the flow rate
                               per minute),          exceeded the
                               whichever is          maximum rated flow
                               greater, for liquid   rate of the sensor,
                               flow rate.            or the data
                              b. 5       recorder was off
                               percent over the      scale.
                               normal range of      e. Checks of all
                               flow measured or      mechanical
                               280 liters per        connections for
                               minute (10 cubic      leakage monthly.
                               feet per minute),    f. Visual
                               whichever is          inspections and
                               greater, for gas      checks of CPMS
                               flow rate.            operation every 3
                              c. 5       months, unless the
                               percent over the      CPMS has a
                               normal range          redundant flow
                               measured for mass     sensor.
                               flow rate.           g. Selection of a
                                                     representative
                                                     measurement
                                                     location where
                                                     swirling flow or
                                                     abnormal velocity
                                                     distributions due
                                                     to upstream and
                                                     downstream
                                                     disturbances at the
                                                     point of
                                                     measurement are
                                                     minimized.
pH..........................  a. 0.2    b. Performance
                               pH units.             evaluation
                                                     annually. Conduct a
                                                     two-point
                                                     calibration with
                                                     one of the two
                                                     buffer solutions
                                                     having a pH within
                                                     1 of the pH of the
                                                     operating limit.
                                                    c. Visual
                                                     inspections and
                                                     checks of CPMS
                                                     operation every 3
                                                     months, unless the
                                                     CPMS has a
                                                     redundant pH
                                                     sensor.
                                                    d. Select a
                                                     measurement
                                                     location that
                                                     provides a
                                                     representative
                                                     sample of scrubber
                                                     effluent and that
                                                     ensures the fluid
                                                     is properly mixed.
4. Specific Gravity.........  a. 0.02   b. Performance
                               specific gravity      evaluation
                               units.                annually.
                                                    c. Visual
                                                     inspections and
                                                     checks of CPMS
                                                     operation every 3
                                                     months, unless the
                                                     CPMS has a
                                                     redundant specific
                                                     gravity sensor.
                                                    d. Select a
                                                     measurement
                                                     location that
                                                     provides a
                                                     representative
                                                     sample of specific
                                                     gravity of the
                                                     absorbing liquid
                                                     effluent and that
                                                     ensures the fluid
                                                     is properly mixed.
------------------------------------------------------------------------

PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS 
FOR SOURCE CATEGORIES

0
40. The authority citation for part 63 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart A--General Provisions

0
41. Amend Sec.  63.14 by:
0
a. Revising paragraphs (a), (c), and (f), and (i) introductory text;
0
b. Redesignating paragraphs (i)(33) through (91) as (i)(34) through 
(92);
0
c. Adding new paragraph (i)(33);
0
d. Revising newly redesignated paragraphs (i)(89) and (96);
0
e. Removing note 1 to paragraph (i);
0
f. Revising and republishing paragraph (o); and
0
g. Revising paragraph (u).
    The revisions, addition, and republication read as follows:


Sec.  63.14  Incorporations by reference.

    (a)(1) Certain material is incorporated by reference into this part 
with the approval of the Director of the Federal Register under 5 
U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other than that 
specified in this section, the U.S. Environmental Protection Agency 
(EPA) must publish a document in the Federal Register and the material 
must be available to the public. All approved incorporation by 
reference (IBR) material is available for inspection at the EPA and at 
the National Archives and Records Administration (NARA). Contact the 
EPA at: EPA Docket Center, Public Reading Room, EPA WJC West, Room 
3334, 1301 Constitution Ave. NW, Washington, DC; phone: (202) 566-1744. 
For information on the availability of this material at NARA, visit 
www.archives.gov/federal-register/cfr/ibr-locations or email 
[email protected].
    (2) The IBR material may be obtained from the sources in the 
following paragraphs of this section or from one or more private 
resellers listed in this paragraph (a)(2). For material that is no 
longer commercially available, contact: the EPA (see paragraph (a)(1) 
of this section).
    (i) Accuris Standards Store, 321 Inverness Drive, South Englewood, 
CO, 80112; phone: (800) 332-6077; website: https://store.accuristech.com.
    (ii) American National Standards Institute (ANSI), 25 West 43rd 
Street, Fourth Floor, New York, NY 10036-7417; phone: (212) 642-4980; 
email: [email protected]; website: www.ansi.org.
    (iii) GlobalSpec, 257 Fuller Road, Suite NFE 1100, Albany, NY 
12203-3621; phone: (800) 261-2052; website: https://standards.globalspec.com.
    (iv) Nimonik Document Center, 401 Roland Way, Suite 224, Oakland, 
CA, 94624; phone (650) 591-7600; email: center.com">info@document-center.com; 
website: www.document-center.com.
    (v) Techstreet, phone: (855) 999-9870; email: [email protected]; 
website: www.techstreet.com.
* * * * *
    (c) American Petroleum Institute (API), 200 Massachusetts Ave. NW, 
Suite 1100, Washington, DC 20001; phone: (202) 682-8000; website: 
www.api.org.
    (1) API Publication 2517, Evaporative Loss from External Floating-
Roof Tanks, Third Edition, February 1989; IBR approved for Sec. Sec.  
63.111; 63.1402; 63.2406; 63.7944.
    (2) API Publication 2518, Evaporative Loss from Fixed-roof Tanks, 
Second Edition, October 1991; IBR approved for Sec.  63.150(g).
    (3) API Manual of Petroleum Measurement Specifications (MPMS) 
Chapter 19.2 (API MPMS 19.2), Evaporative Loss From Floating-Roof 
Tanks, First Edition, April 1997; IBR approved for Sec. Sec.  63.1251; 
63.12005.

[[Page 43152]]

    (4) API Manual of Petroleum Measurement Specifications (MPMS) 
Chapter 19.2 (API MPMS 19.2), Evaporative Loss From Floating-Roof 
Tanks, Fourth Edition, August 2020; IBR approved for Sec.  63.101(b).
* * * * *
    (f) American Society of Mechanical Engineers (ASME), Two Park 
Avenue, New York, NY 10016-5990; phone: (800) 843-2763; email: 
[email protected]; website: www.asme.org.
    (1) ANSI/ASME PTC 19.10-1981, Flue and Exhaust Gas Analyses [Part 
10, Instruments and Apparatus], issued August 31, 1981, IBR approved 
for Sec. Sec.  63.116(c) and (h); 63.128(a); 63.145(i); 63.309(k); 
63.365(b); 63.457(k); 63.490(g); 63.772(e) and (h); 63.865(b); 
63.997(e); 63.1282(d) and (g); 63.1625(b); table 5 to subpart EEEE; 
Sec. Sec.  63.3166(a); 63.3360(e); 63.3545(a); 63.3555(a); 63.4166(a); 
63.4362(a); 63.4766(a); 63.4965(a); 63.5160(d); table 4 to subpart 
UUUU; table 3 to subpart YYYY; Sec. Sec.  63.7822(b); 63.7824(e); 
63.7825(b); 63.8000(d); 63.9307(c); 63.9323(a); 63.9621(b) and (c); 
63.11148(e); 63.11155(e); 63.11162(f); 63.11163(g); 63.11410(j); 
63.11551(a); 63.11646(a); 63.11945; table 4 to subpart AAAAA; table 5 
to subpart DDDDD; table 4 to subpart JJJJJ; table 4 to subpart KKKKK; 
table 4 to subpart SSSSS; tables 4 and 5 to subpart UUUUU; table 1 to 
subpart ZZZZZ; table 4 to subpart JJJJJJ.
    (2) [Reserved]
* * * * *
    (i) ASTM International, 100 Barr Harbor Drive, P.O. Box CB700, West 
Conshohocken, Pennsylvania 19428-2959; phone: (800) 262-1373; website: 
www.astm.org.
* * * * *
    (33) ASTM D2879-23, Standard Test Method for Vapor Pressure-
Temperature Relationship and Initial Decomposition Temperature of 
Liquids by Isoteniscope, approved December 1, 2023; IBR approved for 
Sec.  63.101(b).
* * * * *
    (89) ASTM D6348-12 (Reapproved 2020), Standard Test Method for 
Determination of Gaseous Compounds by Extractive Direct Interface 
Fourier Transform Infrared (FTIR) Spectroscopy, approved December 1, 
2020; IBR approved for Sec. Sec.  63.109(a); 63.365(b); 63.509(a); 
63.7825(g) and (h).
* * * * *
    (96) ASTM D6420-18, Standard Test Method for Determination of 
Gaseous Organic Compounds by Direct Interface Gas Chromatography-Mass 
Spectrometry, approved November 1, 2018; IBR approved for Sec. Sec.  
63.101(b); 63.115(g); 63.116(c); 63.126(d); 63.128(a); 63.139(c); 
63.145(d) and (i); 63.150(g); 63.180(d); 63.482(b); 63.485(t); 
63.488(b); 63.490(c) and (e); 63.496(b); 63.500(c); 63.501(a); 
63.502(j); 63.503(a) and(g); 63.525(a) and (e); 63.987(b); 63.997(e); 
63.2354(b;, table 5 to subpart EEEE; Sec. Sec.  63.2450(j); 63.8000(d).
* * * * *
    (o) U.S. Environmental Protection Agency (EPA), 1200 Pennsylvania 
Avenue NW, Washington, DC 20460; phone: (202) 272-0167; website: 
www.epa.gov/aboutepa/forms/contact-epa.
    (1) EPA-453/R-08-002, Protocol for Determining the Daily Volatile 
Organic Compound Emission Rate of Automobile and Light-Duty Truck 
Primer-Surfacer and Topcoat, published September 2008; IBR approved for 
Sec. Sec.  63.3130(c); 63.3161(d) and (g); 63.3165(e); appendix A to 
subpart IIII.
    (2) EPA-453/R-01-005, National Emission Standards for Hazardous Air 
Pollutants (NESHAP) for Integrated Iron and Steel Plants--Background 
Information for Proposed Standards, Final Report, January 2001; IBR 
approved for Sec.  63.7491(g).
    (3) EPA-454/B-08-002, Quality Assurance Handbook for Air Pollution 
Measurement Systems; Volume IV: Meteorological Measurements, Version 
2.0 (Final), Issued March 2008; IBR approved for Sec. Sec.  63.184(c); 
63.7792(b).
    (4) EPA-454/R-98-015, Office of Air Quality Planning and Standards 
(OAQPS), Fabric Filter Bag Leak Detection Guidance, September 1997; IBR 
approved for Sec. Sec.  63.548(e); 63.864(e); 63.7525(j); 63.8450(e); 
63.8600(e); 63.9632(a); 63.9804(f); 63.11224(f); 63.11423(e). 
(Available at: https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=2000D5T6.pdf).
    (5) EPA-454/R-99-005, Office of Air Quality Planning and Standards 
(OAQPS), Meteorological Monitoring Guidance for Regulatory Modeling 
Applications, February 2000; IBR approved for appendix A to this part.
    (6) EPA/600/R-12/531, EPA Traceability Protocol for Assay and 
Certification of Gaseous Calibration Standards, May 2012; IBR approved 
for Sec.  63.2163(b).
    (7) EPA-625/3-89-016, Interim Procedures for Estimating Risks 
Associated with Exposures to Mixtures of Chlorinated Dibenzo-p-Dioxins 
and -Dibenzofurans (CDDs and CDFs) and 1989 Update, March 1989; IBR 
approved for Sec.  63.1513(d).
    (8) EPA-821-R-02-019, Method 1631 Revision E, Mercury in Water by 
Oxidation, Purge and Trap, and Cold Vapor Atomic Absorption 
Fluorescence Spectrometry, Revision E, August 2002; IBR approved for 
table 6 to subpart DDDDD.
    (9) EPA Method 200.8, Determination of Trace Elements in Waters and 
Wastes by Inductively Coupled Plasma--Mass Spectrometry, Revision 5.4, 
1994; IBR approved for table 6 to subpart DDDDD.
    (10) In EPA Publication No. SW-846, Test Methods for Evaluating 
Solid Waste, Physical/Chemical Methods (Available from: www.epa.gov/hw-sw846/sw-846-compendium):
    (i) SW-846-0011, Sampling for Selected Aldehyde and Ketone 
Emissions from Stationary Sources, Revision 0, December 1996; IBR 
approved for table 4 to subpart DDDD.
    (ii) SW-846-3020A, Acid Digestion of Aqueous Samples And Extracts 
For Total Metals For Analysis By GFAA Spectroscopy, Revision 1, July 
1992; IBR approved for table 6 to subpart DDDDD; table 5 to subpart 
JJJJJJ.
    (iii) SW-846-3050B, Acid Digestion of Sediments, Sludges, and 
Soils, Revision 2, December 1996; IBR approved for table 6 to subpart 
DDDDD; table 5 to subpart JJJJJJ.
    (iv) SW-846-5030B, Purge-And-Trap For Aqueous Samples, Revision 2, 
December 1996; IBR approved for Sec. Sec.  63.109(b), (c), (d), and 
(e); 63.509(b) and (c); 63.2492(b) and (c).
    (v) SW-846-5031, Volatile, Nonpurgeable, Water-Soluble Compounds by 
Azeotropic Distillation, Revision 0, December 1996; IBR approved for 
Sec. Sec.  63.109(b), (c), (d), and (e); 63.509(b) and (c); 63.2492(b) 
and (c).
    (vi) SW-846-7470A, Mercury In Liquid Waste (Manual Cold-Vapor 
Technique), Revision 1, September 1994; IBR approved for table 6 to 
subpart DDDDD; table 5 to subpart JJJJJJ.
    (vii) SW-846-7471B, Mercury In Solid Or Semisolid Waste (Manual 
Cold-Vapor Technique), Revision 2, February 2007; IBR approved for 
table 6 to subpart DDDDD; table 5 to subpart JJJJJJ.
    (viii) SW-846-8015C, Nonhalogenated Organics by Gas Chromatography, 
Revision 3, February 2007; IBR approved for Sec. Sec.  63.11960; 
63.11980; table 10 to subpart HHHHHHH.
    (ix) SW-846-8260B, Volatile Organic Compounds by Gas 
Chromatography/Mass Spectrometry (GC/MS), Revision 2, December 1996; 
IBR approved for Sec. Sec.  63.1107(a); 63.11960; 63.11980; table 10 to 
subpart HHHHHHH.
    (x) SW-846-8260D, Volatile Organic Compounds By Gas Chromatography/
Mass Spectrometry, Revision 4, June 2018; IBR approved for Sec. Sec.  
63.109(b), (c), (d), and (e); 63.509(b) and (c); 63.2492(b) and (c).

[[Page 43153]]

    (xi) SW-846-8270D, Semivolatile Organic Compounds by Gas 
Chromatography/Mass Spectrometry (GC/MS), Revision 4, February 2007; 
IBR approved for Sec. Sec.  63.1107(a); 63.11960; 63.11980; table 10 to 
subpart HHHHHHH.
    (xii) SW-846-8315A, Determination of Carbonyl Compounds by High 
Performance Liquid Chromatography (HPLC), Revision 1, December 1996; 
IBR approved for Sec. Sec.  63.11960; 63.11980; table 10 to subpart 
HHHHHHH.
    (xiii) SW-846-5050, Bomb Preparation Method for Solid Waste, 
Revision 0, September 1994; IBR approved for table 6 to subpart DDDDD.
    (xiv) SW-846-6010C, Inductively Coupled Plasma-Atomic Emission 
Spectrometry, Revision 3, February 2007; IBR approved for table 6 to 
subpart DDDDD.
    (xv) SW-846-6020A, Inductively Coupled Plasma-Mass Spectrometry, 
Revision 1, February 2007; IBR approved for table 6 to subpart DDDDD.
    (xvi) SW-846-7060A, Arsenic (Atomic Absorption, Furnace Technique), 
Revision 1, September 1994; IBR approved for table 6 to subpart DDDDD.
    (xvii) SW-846-7740, Selenium (Atomic Absorption, Furnace 
Technique), Revision 0, September 1986; IBR approved for table 6 to 
subpart DDDDD.
    (xviii) SW-846-9056, Determination of Inorganic Anions by Ion 
Chromatography, Revision 1, February 2007; IBR approved for table 6 to 
subpart DDDDD.
    (xix) SW-846-9076, Test Method for Total Chlorine in New and Used 
Petroleum Products by Oxidative Combustion and Microcoulometry, 
Revision 0, September 1994; IBR approved for table 6 to subpart DDDDD.
    (xx) SW-846-9250, Chloride (Colorimetric, Automated Ferricyanide 
AAI), Revision 0, September 1986; IBR approved for table 6 to subpart 
DDDDD.
* * * * *
    (u) Texas Commission on Environmental Quality (TCEQ) Library, Post 
Office Box 13087, Austin, Texas 78711-3087; phone: (512) 239-0028; 
email: www.tceq.texas.gov">info@www.tceq.texas.gov; website: www.tceq.texas.gov.
    (1) ``Air Stripping Method (Modified El Paso Method) for 
Determination of Volatile Organic Compound Emissions from Water 
Sources,'' Revision Number One, dated January 2003, Sampling Procedures 
Manual, Appendix P: Cooling Tower Monitoring, January 31, 2003; IBR 
approved for Sec. Sec.  63.104(f) and (g); 63.654(c) and (g); 
63.655(i); 63.1086(e); 63.1089; 63.2490(d); 63.2525(r); 63.11920. 
(Available from: www.tceq.texas.gov/downloads/compliance/investigations/assistance/samplingappp.pdf).
    (2) [Reserved]

0
42. Revise the heading of subpart F to read as follows:

Subpart F--National Emission Standards for Hazardous Air Pollutants 
From the Synthetic Organic Chemical Manufacturing Industry

0
43. Amend Sec.  63.100 by:
0
a. Revising paragraphs (a), (e)(1) and (3), (f)(8) and (11), (j)(3), 
(k) introductory text, (k)(4) introductory text, (k)(5)(ii), and 
(k)(6)(i);
0
b. Adding paragraphs (k)(10) through (12);
0
c. Revising paragraphs (l)(1)(iii), (l)(4)(ii)(B), (m) introductory 
text, (q) introductory text, (q)(3), and (q)(4)(i) introductory text;
0
d. Adding paragraph (q)(4)(iii); and
0
e. Revising paragraph (q)(5).
    The revisions and additions read as follows:


Sec.  63.100  Applicability and designation of source.

    (a) This subpart provides applicability provisions, definitions, 
and other general provisions that are applicable to subparts G and H of 
this part. This subpart also provides requirements for certain heat 
exchange systems, maintenance wastewater, and flares.
* * * * *
    (e) * * *
    (1) This subpart applies to maintenance wastewater and heat 
exchange systems within a source that is subject to this subpart; and 
also applies to flares used to reduce organic HAP emissions from a 
source.
* * * * *
    (3) This subpart and subpart H of this part apply to pumps, 
compressors, agitators, pressure relief devices, sampling connection 
systems, open-ended valves or lines, valves, connectors, 
instrumentation systems, surge control vessels, and bottoms receivers 
within a source that is subject to this subpart. Subpart H also 
contains fenceline monitoring requirements that apply to all emission 
sources (i.e., maintenance wastewater, heat exchange systems, process 
vents, storage vessels, transfer racks, equipment identified in Sec.  
63.149, wastewater streams and associated treatment residuals within a 
source, and pumps, compressors, agitators, pressure relief devices, 
sampling connection systems, open-ended valves or lines, valves, 
connectors, instrumentation systems, surge control vessels, and bottoms 
receivers within a source). If specific items of equipment, comprising 
part of a chemical manufacturing process unit subject to this subpart, 
are managed by different administrative organizations (e.g., different 
companies, affiliates, departments, divisions, etc.), those items of 
equipment may be aggregated with any chemical manufacturing process 
unit within the source for all purposes under subpart H, providing 
there is no delay in the applicable compliance date in Sec.  63.100(k).
    (f) * * *
    (8) Except for storage vessels in ethylene oxide service, vessels 
storing organic liquids that contain organic hazardous air pollutants 
only as impurities;
* * * * *
    (11) Equipment that is intended to operate in organic hazardous air 
pollutant service, as defined in Sec.  63.101, for less than 300 hours 
during the calendar year.
* * * * *
    (j) * * *
    (3) Ethylene production units, regardless of whether the units 
supply feedstocks that include chemicals listed in table 1 of this 
subpart to chemical manufacturing process units that are subject to the 
provisions of subpart F, G, or H of this part.
* * * * *
    (k) Except as provided in paragraphs (l), (m), and (p) of this 
section, sources subject to subpart F, G, or H of this part are 
required to achieve compliance on or before the dates specified in 
paragraphs (k)(1) through (8) and (10) and (11) of this section.
* * * * *
    (4) Existing chemical manufacturing process units in Groups I and 
II as identified in table 1 of this subpart shall be in compliance with 
the requirements of Sec.  63.164 no later than May 10, 1995, for any 
compressor meeting one or more of the criteria in paragraphs (k)(4)(i) 
through (iv) of this section, if the work can be accomplished without a 
process unit shutdown, as defined in Sec.  63.101.
* * * * *
    (5) * * *
    (ii) The work can be accomplished without a process unit shutdown 
as defined in Sec.  63.101;
* * * * *
    (6)(i) If compliance with the compressor provisions of Sec.  63.164 
cannot reasonably be achieved without a process unit shutdown, as 
defined in Sec.  63.101, the owner or operator shall achieve compliance 
no later than April 22, 1996, except as provided for in paragraph 
(k)(6)(ii) of this section. The

[[Page 43154]]

owner or operator who elects to use this provision shall comply with 
the requirements of Sec.  63.103(g).
* * * * *
    (10) All affected sources that commenced construction or 
reconstruction on or before April 25, 2023, must be in compliance with 
the requirements listed in paragraphs (k)(10)(i) through (viii) of this 
section upon initial startup or on July 15, 2027, whichever is later. 
All affected sources that commenced construction or reconstruction 
after April 25, 2023, must be in compliance with the requirements 
listed in paragraphs (k)(10)(i) through (viii) of this section upon 
initial startup, or on July 15, 2024, whichever is later.
    (i) The general requirements specified in paragraph (q)(4)(iii) of 
this section, Sec. Sec.  63.102(e) and (f), 63.103(b)(1), (b)(3)(ii), 
and (c)(2)(iv), 63.107(j), 63.108, 63.110(h)(2) and (j)(1), and Sec.  
63.148(f)(4), (i)(3)(iii), and (j)(4).
    (ii) For heat exchange systems, the requirements specified in Sec.  
63.104(a)(3) and (a)(4)(v) (g), (h), (i), (j), and (l).
    (iii) For process vents, the requirements specified in Sec. Sec.  
63.113(a)(4) and (5), (k), and (l), 63.114(a)(5)(v) and (d)(3), 
63.115(g), 63.116(g), 63.117(g), and 63.118(f)(7) and (n).
    (iv) For storage vessels, the requirements specified in Sec. Sec.  
63.119(a)(6), 63.119(b)(5)(ix) through (xii), 63.119(b)(7), 
63.119(f)(3)(iv), 63.120(d)(1)(iii), and footnotes b and c of tables 5 
and 6 to subpart G of this part. For pressure vessels, the requirements 
specified in Sec. Sec.  63.119(a)(7), 63.122(j), and 63.123(b).
    (v) For transfer operations, the requirements specified in 
Sec. Sec.  63.126(h)(1), 63.127(b)(4) and (d)(3), and 63.130(a)(2)(iv), 
(b)(3), and (d)(7).
    (vi) For process wastewater, the requirements specified in 
Sec. Sec.  63.132(a)(2)(i)(C) and (b)(3)(i)(C), 63.135(b)(4), 
63.139(d)(5), and 63.145(a)(10).
    (vii) For equipment leaks and pressure relief devices, the 
requirements specified in Sec. Sec.  63.165(a) and (e), 63.170(b), 
63.172(j)(4), 63.181(g)(3)(iii), and 63.182(d)(2)(xix).
    (viii) The other notification, reports, and records requirements 
specified in Sec.  63.152(c)(2)(ii)(F), table 3 to subpart G of this 
part, item 3 in column 3 for presence of flow and monthly inspections 
of sealed valves for all control devices, table 7 to subpart G of this 
part, item 3 in column 3 for presence of flow and monthly inspections 
of sealed valves for all control devices and vapor balancing systems, 
and table 20 to subpart G of this part, item (8)(iii).
    (11) All affected sources that commenced construction or 
reconstruction on or before April 25, 2023, must be in compliance with 
the ethylene oxide requirements in Sec. Sec.  63.104(k), 63.109, 
63.113(j), 63.119(a)(5), 63.120(d)(9), 63.124, 63.163(a)(1)(iii), 
(b)(2)(iv), (c)(4), and (e)(7), 63.168(b)(2)(iv) and (d)(5), 63.171(f), 
and 63.174(a)(3), (b)(3)(vi), (b)(5), and (g)(3), upon initial startup 
or on July 15, 2026, whichever is later. All affected sources that 
commenced construction or reconstruction after April 25, 2023, must be 
in compliance with the ethylene oxide requirements listed in Sec. Sec.  
63.104(k), 63.109, 63.113(j), 63.119(a)(5), 63.120(d)(9), Sec.  63.124, 
63.163(a)(1)(iii), (b)(2)(iv), (c)(4), and (e)(7), 63.168(b)(2)(iv) and 
(d)(5), Sec.  63.171(f), and 63.174(a)(3), (b)(3)(vi), (b)(5), and 
(g)(3), upon initial startup or on July 15, 2024, whichever is later.
    (12) All affected sources that commenced construction or 
reconstruction on or before April 25, 2023, must commence fenceline 
monitoring according to the requirements in Sec.  63.184 by no later 
than July 15, 2026, however requirements for corrective actions are not 
required until on or after July 15, 2027. All affected sources that 
commenced construction or reconstruction after April 25, 2023, must be 
in compliance with the fenceline monitoring requirements listed in 
Sec.  63.184 upon initial startup, or on July 15, 2024, whichever is 
later.
    (l) * * *
    (1) * * *
    (iii) The addition has the potential to emit 10 tons per year or 
more of any HAP or 25 tons per year or more of any combination of 
HAP's, unless the Administrator establishes a lesser quantity.
* * * * *
    (4) * * *
    (ii) * * *
    (B) If a deliberate operational process change to an existing 
chemical manufacturing process unit causes a Group 2 emission point to 
become a Group 1 emission point, if a surge control vessel or bottoms 
receiver becomes subject to Sec.  63.170, or if a compressor becomes 
subject to Sec.  63.164, the owner or operator shall be in compliance 
upon initial start-up or by 3 years after April 22, 1994, whichever is 
later, unless the owner or operator demonstrates to the Administrator 
that achieving compliance will take longer than making the change. If 
this demonstration is made to the Administrator's satisfaction, the 
owner or operator shall follow the procedures in paragraphs (m)(1) 
through (3) of this section to establish a compliance date.
* * * * *
    (m) If a change that does not meet the criteria in paragraph (l)(4) 
of this section is made to a chemical manufacturing process unit 
subject to subparts F and G of this part, and the change causes a Group 
2 emission point to become a Group 1 emission point (as defined in 
Sec.  63.101), then the owner or operator shall comply with the 
requirements of subpart G of this part for the Group 1 emission point 
as expeditiously as practicable, but in no event later than 3 years 
after the emission point becomes Group 1.
* * * * *
    (q) If the owner or operator of a process vent, or of a gas stream 
transferred subject to Sec.  63.113(i), is unable to comply with the 
provisions of Sec. Sec.  63.113 through 63.118 by the applicable 
compliance date specified in paragraph (k), (l), or (m) of this section 
for the reasons stated in paragraph (q)(1), (3), or (5) of this 
section, the owner or operator shall comply with the applicable 
provisions in Sec. Sec.  63.113 through 63.118 as expeditiously as 
practicable, but in no event later than the date approved by the 
Administrator pursuant to paragraph (q)(2), (4), or (6) of this 
section, respectively. For requests under paragraph (q)(1) or (3) of 
this section, the date approved by the Administrator may be earlier 
than, and shall not be later than, the later of January 22, 2004, or 3 
years after the transferee's refusal to accept the stream for disposal. 
For requests submitted under paragraph (q)(5) of this section, the date 
approved by the Administrator may be earlier than, and shall not be 
later than, 3 years after the date of publication of the amendments to 
this subpart or to subpart G of this part which created the need for an 
extension of the compliance.
* * * * *
    (3) Except as specified in paragraph (q)(4)(iii) of this section, 
if the owner or operator has been sending the gas stream for disposal 
as described in Sec.  63.113(i) to a transferee who had submitted a 
written certification as described in Sec.  63.113(i)(2), and the 
transferee revokes its written certification, the owner or operator 
shall comply with paragraphs (q)(4)(i) and (ii) of this section. During 
the period between the date when the owner or operator receives notice 
of revocation of the transferee's written certification and the 
compliance date established under paragraph (q)(4) of this section, the

[[Page 43155]]

owner or operator shall implement, to the extent reasonably available, 
measures to prevent or minimize excess emissions to the extent 
practical. For purposes of this paragraph (q)(3), the term ``excess 
emissions'' means emissions in excess of those that would have occurred 
if the transferee had continued managing the gas stream in compliance 
with the requirements in Sec. Sec.  63.113 through 63.118. The measures 
to be taken shall be identified in the applicable startup, shutdown, 
and malfunction plan. If the measures that can be reasonably taken will 
change over time, so that a more effective measure which could not 
reasonably be taken initially would be reasonable at a later date, the 
Administrator may require the more effective measure by a specified 
date (in addition to or instead of any other measures taken sooner or 
later than that date) as a condition of approval of the compliance 
schedule.
    (4) * * *
    (i) An owner or operator directed to comply with this paragraph 
(q)(4) shall submit to the Administrator for approval the documents 
specified in paragraphs (q)(4)(i)(A) through (E) of this section no 
later than 90 days after the owner or operator receives notice of 
revocation of the transferee's written certification.
* * * * *
    (iii) For each source as defined in Sec.  63.101, beginning no 
later than the compliance dates specified in Sec.  63.100(k)(10), 
paragraph (q)(3) of this section no longer applies.
    (5) If the owner's or operator's inability to meet otherwise 
applicable compliance deadlines is due to amendments of this subpart or 
of subpart G of this part published on or after January 22, 2001, and 
neither condition specified in paragraph (q)(1) or (3) of this section 
is applicable, the owner or operator shall comply with paragraph (q)(6) 
of this section.
* * * * *

0
44. Amend Sec.  63.101 by revising paragraph (b) to read as follows:


Sec.  63.101  Definitions.

* * * * *
    (b) All other terms used in this subpart and subparts G and H of 
this part shall have the meaning given them in the Act and in this 
section. If the same term is defined in subpart A of this part and in 
this section, it shall have the meaning given in this section for 
purposes of subparts F, G, and H of this part.
    Air oxidation reactor means a device or vessel in which air, or a 
combination of air and oxygen, is used as an oxygen source in 
combination with one or more organic reactants to produce one or more 
organic compounds. Air oxidation reactor includes the product separator 
and any associated vacuum pump or steam jet.
    Ancillary activities means boilers and incinerators (not used to 
comply with the emission limits of subparts F, G, and H of this part), 
chillers and refrigeration systems, and other equipment and activities 
that are not directly involved (i.e., they operate within a closed 
system and materials are not combined with process fluids) in the 
processing of raw materials or the manufacturing of a product or 
isolated intermediate.
    Annual average concentration, as used in the wastewater provisions, 
means the flow-weighted annual average concentration, as determined 
according to the procedures specified in Sec.  63.144(b).
    Annual average flow rate, as used in the wastewater provisions, 
means the annual average flow rate, as determined according to the 
procedures specified in Sec.  63.144(c).
    Automated monitoring and recording system means any means of 
measuring values of monitored parameters and creating a hard copy or 
computer record of the measured values that does not require manual 
reading of monitoring instruments and manual transcription of data 
values. Automated monitoring and recording systems include, but are not 
limited to, computerized systems and strip charts.
    Batch operation means a noncontinuous operation in which a discrete 
quantity or batch of feed is charged into a unit operation within a 
chemical manufacturing process unit and processed at one time. Batch 
operation includes noncontinuous operations in which the equipment is 
fed intermittently or discontinuously. Addition of raw material and 
withdrawal of product do not occur simultaneously in a batch operation. 
After each batch operation, the equipment is generally emptied before a 
fresh batch is started.
    Batch process means a process in which the equipment is fed 
intermittently or discontinuously. Processing then occurs in this 
equipment after which the equipment is generally emptied. Examples of 
industries that use batch processes include pharmaceutical production 
and pesticide production.
    Batch process vent means gaseous venting to the atmosphere from a 
batch operation.
    Batch product-process equipment train means the collection of 
equipment (e.g., connectors, reactors, valves, pumps, etc.) configured 
to produce a specific product or intermediate by a batch process.
    Bench-scale batch process means a batch process (other than a 
research and development facility) that is operated on a small scale, 
such as one capable of being located on a laboratory bench top. This 
bench-scale equipment will typically include reagent feed vessels, a 
small reactor and associated product separator, recovery and holding 
equipment. These processes are only capable of producing small 
quantities of product.
    Boiler means any enclosed combustion device that extracts useful 
energy in the form of steam and is not an incinerator. Boiler also 
means any industrial furnace as defined in 40 CFR 260.10.
    Bottoms receiver means a tank that collects distillation bottoms 
before the stream is sent for storage or for further downstream 
processing.
    Breakthrough means the time when the level of HAP or TOC, measured 
at the outlet of the first bed, has been detected is at the highest 
concentration allowed to be discharged from the adsorber system and 
indicates that the adsorber bed should be replaced.
    By compound means by individual stream components, not carbon 
equivalents.
    By-product means a chemical that is produced coincidentally during 
the production of another chemical.
    Car-seal means a seal that is placed on a device that is used to 
change the position of a valve (e.g., from opened to closed) in such a 
way that the position of the valve cannot be changed without breaking 
the seal.
    Chemical manufacturing process unit or CMPU means the equipment 
assembled and connected by pipes or ducts to process raw materials and 
to manufacture an intended product. A chemical manufacturing process 
unit consists of more than one unit operation. For the purpose of this 
subpart, chemical manufacturing process unit includes air oxidation 
reactors and their associated product separators and recovery devices; 
reactors and their associated product separators and recovery devices; 
distillation units and their associated distillate receivers and 
recovery devices; associated unit operations; associated recovery 
devices; and any feed, intermediate and product storage vessels and 
pressure vessels, product transfer racks, and connected ducts and 
piping. A chemical manufacturing process unit includes pumps, 
compressors, agitators, pressure relief devices, sampling connection 
systems,

[[Page 43156]]

open-ended valves or lines, valves, connectors, instrumentation 
systems, and control devices or systems. A chemical manufacturing 
process unit is identified by its primary product. Ancillary activities 
are not considered a process or part of any process. Quality assurance/
quality control laboratories are not considered part of any process.
    Closed biological treatment process means a tank or surface 
impoundment where biological treatment occurs and air emissions from 
the treatment process are routed to either a control device by means of 
a closed vent system or to a fuel gas system by means of hard-piping. 
The tank or surface impoundment has a fixed roof, as defined in this 
section, or a floating flexible membrane cover that meets the 
requirements specified in Sec.  63.134.
    Closed-loop system means an enclosed system that returns process 
fluid to the process and is not vented to the atmosphere except through 
a closed-vent system.
    Closed-purge system means a system or combination of system and 
portable containers, to capture purged liquids. Containers must be 
covered or closed when not being filled or emptied.
    Closed vent system means a system that is not open to the 
atmosphere and is composed of piping, ductwork, connections, and, if 
necessary, flow inducing devices that transport gas or vapor from an 
emission point to a control device.
    Combustion device means an individual unit of equipment, such as a 
flare, incinerator, process heater, or boiler, used for the combustion 
of organic hazardous air pollutant emissions.
    Compliance date means the dates specified in Sec.  63.100(k) or 
(l)(3) for process units subject to subpart F of this part; the dates 
specified in Sec.  63.190(e) for process units subject to subpart I of 
this part. For sources subject to other subparts in this part that 
reference this subpart, compliance date will be defined in those 
subparts. However, the compliance date for Sec.  63.170 shall be no 
later than 3 years after the effective date of those subparts unless 
otherwise specified in such other subparts.
    Connector means flanged, screwed, or other joined fittings used to 
connect two pipe lines or a pipe line and a piece of equipment. A 
common connector is a flange. Joined fittings welded completely around 
the circumference of the interface are not considered connectors for 
the purpose of this regulation. For the purpose of reporting and 
recordkeeping, connector means joined fittings that are not 
inaccessible, glass, or glass-lined as described in Sec.  63.174(h).
    Container, as used in the wastewater provisions, means any portable 
waste management unit that has a capacity greater than or equal to 0.1 
m\3\ in which a material is stored, transported, treated, or otherwise 
handled. Examples of containers are drums, barrels, tank trucks, 
barges, dumpsters, tank cars, dump trucks, and ships.
    Continuous record means documentation, either in hard copy or 
computer readable form, of data values measured at least once every 15 
minutes and recorded at the frequency specified in Sec.  63.152(f) or 
(g).
    Continuous recorder means a data recording device that either 
records an instantaneous data value at least once every 15 minutes or 
records 15-minute or more frequent block average values.
    Continuous seal means a seal that forms a continuous closure that 
completely covers the space between the wall of the storage vessel and 
the edge of the floating roof. A continuous seal may be a vapor-
mounted, liquid-mounted, or metallic shoe seal. A continuous seal may 
be constructed of fastened segments so as to form a continuous seal.
    Continuous vapor processing system means a vapor processing system 
that treats total organic compound vapors collected from tank trucks or 
railcars on a demand basis without intermediate accumulation in a vapor 
holder.
    Control device means any combustion device, recovery device, or 
recapture device. Such equipment includes, but is not limited to, 
absorbers, carbon adsorbers, condensers, incinerators, flares, boilers, 
and process heaters. For process vents, recapture devices are 
considered control devices but recovery devices are not considered 
control devices, and for a steam stripper, a primary condenser is not 
considered a control device.
    Co-product means a chemical that is produced during the production 
of another chemical.
    Cover, as used in the wastewater provisions, means a device or 
system which is placed on or over a waste management unit containing 
wastewater or residuals so that the entire surface area is enclosed to 
minimize air emissions. A cover may have openings necessary for 
operation, inspection, and maintenance of the waste management unit 
such as access hatches, sampling ports, and gauge wells provided that 
each opening is closed when not in use. Examples of covers include a 
fixed roof installed on a wastewater tank, a lid installed on a 
container, and an air-supported enclosure installed over a waste 
management unit.
    Dioxins and furans means total tetra-through octachlorinated 
dibenzo-p-dioxins and dibenzofurans.
    Distillate receiver means overhead receivers, overhead 
accumulators, reflux drums, and condenser(s) including ejector-
condenser(s) associated with a distillation unit.
    Distillation unit means a device or vessel in which one or more 
feed streams are separated into two or more exit streams, each exit 
stream having component concentrations different from those in the feed 
stream(s). The separation is achieved by the redistribution of the 
components between the liquid and the vapor phases by vaporization and 
condensation as they approach equilibrium within the distillation unit. 
Distillation unit includes the distillate receiver, reboiler, and any 
associated vacuum pump or steam jet.
    Double block and bleed system means two block valves connected in 
series with a bleed valve or line that can vent the line between the 
two block valves.
    Duct work means a conveyance system such as those commonly used for 
heating and ventilation systems. It is often made of sheet metal and 
often has sections connected by screws or crimping. Hard-piping is not 
ductwork.
    Emission point means an individual process vent, storage vessel, 
transfer rack, wastewater stream, or equipment leak.
    Empty or emptying means the removal of the stored liquid from a 
storage vessel. Storage vessels where stored liquid is left on the 
walls, as bottom clingage, or in pools due to bottom irregularities are 
considered empty. Lowering of the stored liquid level, so that the 
floating roof is resting on its legs, as necessitated by normal vessel 
operation (for example, when changing stored material or when 
transferring material out of the vessel for shipment) is not considered 
emptying.
    Enhanced biological treatment system or enhanced biological 
treatment process means an aerated, thoroughly mixed treatment unit(s) 
that contains biomass suspended in water followed by a clarifier that 
removes biomass from the treated water and recycles recovered biomass 
to the aeration unit. The mixed liquor volatile suspended solids 
(biomass) is greater than 1 kilogram per cubic meter throughout each 
aeration unit. The biomass is suspended and aerated in the water of the 
aeration unit(s) by either submerged air flow or mechanical agitation. 
A thoroughly mixed treatment unit is a unit that is designed and 
operated to approach or

[[Page 43157]]

achieve uniform biomass distribution and organic compound concentration 
throughout the aeration unit by quickly dispersing the recycled biomass 
and the wastewater entering the unit.
    Equipment leak means emissions of organic hazardous air pollutants 
from a connector, pump, compressor, agitator, pressure relief device, 
sampling connection system, open-ended valve or line, valve, surge 
control vessel, bottoms receiver, or instrumentation system in organic 
hazardous air pollutant service as defined in this section.
    Equipment means each pump, compressor, agitator, pressure relief 
device, sampling connection system, open-ended valve or line, valve, 
connector, surge control vessel, bottoms receiver, and instrumentation 
system in organic hazardous air pollutant service; and any control 
devices or systems required by this subpart.
    Ethylene production unit means a chemical manufacturing process 
unit in which ethylene and/or propylene are produced by separation from 
petroleum refining process streams or by subjecting hydrocarbons to 
high temperatures in the presence of steam. The ethylene process unit 
includes the separation of ethylene and/or propylene from associated 
streams such as a C4 product, pyrolysis gasoline, and 
pyrolysis fuel oil. The ethylene process does not include the 
manufacture of SOCMI chemicals such as the production of butadiene from 
the C4 stream and aromatics from pyrolysis gasoline.
    External floating roof means a pontoon-type or double-deck-type 
cover that rests on the liquid surface in a storage vessel or waste 
management unit with no fixed roof.
    Fill or filling means the introduction of organic hazardous air 
pollutant into a storage vessel or the introduction of a wastewater 
stream or residual into a waste management unit, but not necessarily to 
complete capacity.
    First attempt at repair means to take action for the purpose of 
stopping or reducing leakage of organic material to the atmosphere, 
followed by monitoring as specified in Sec.  63.180(b) and (c), as 
appropriate, to verify whether the leak is repaired, unless the owner 
or operator determines by other means that the leak is not repaired.
    Fixed roof means a cover that is mounted on a waste management unit 
or storage vessel in a stationary manner and that does not move with 
fluctuations in liquid level.
    Flame zone means the portion of the combustion chamber in a boiler 
or process heater occupied by the flame envelope.
    Flexible operation unit means a chemical manufacturing process unit 
that manufactures different chemical products periodically by 
alternating raw materials or operating conditions. These units are also 
referred to as campaign plants or blocked operations.
    Floating roof means a cover consisting of a double deck, pontoon 
single deck, internal floating cover or covered floating roof, which 
rests upon and is supported by the liquid being contained, and is 
equipped with a closure seal or seals to close the space between the 
roof edge and waste management unit or storage vessel wall.
    Flow indicator means a device which indicates whether gas flow is, 
or whether the valve position would allow gas flow to be, present in a 
line.
    Fuel gas means gases that are combusted to derive useful work or 
heat.
    Fuel gas system means the offsite and onsite piping and flow and 
pressure control system that gathers gaseous stream(s) generated by 
onsite operations, may blend them with other sources of gas, and 
transports the gaseous stream for use as fuel gas in combustion devices 
or in in-process combustion equipment such as furnaces and gas turbines 
either singly or in combination.
    Group 1 process vent means, before July 15, 2027, a process vent 
for which the vent stream flow rate is greater than or equal to 0.005 
standard cubic meter per minute, the total organic HAP concentration is 
greater than or equal to 50 parts per million by volume, and the total 
resource effectiveness index value, calculated according to Sec.  
63.115, is less than or equal to 1.0. On and after July 15, 2027, Group 
1 process vent means a process vent that emits greater than or equal to 
1.0 pound per hour of total organic HAP.
    Group 1 storage vessel means a storage vessel that meets the 
criteria for design storage capacity and stored-liquid maximum true 
vapor pressure specified in table 5 to subpart G of this part for 
storage vessels at existing sources, and in table 6 to subpart G of 
this part for storage vessels at new sources.
    Group 1 transfer rack means a transfer rack that annually loads 
greater than or equal to 0.65 million liter of liquid products that 
contain organic hazardous air pollutants with a rack weighted average 
vapor pressure greater than or equal to 10.3 kilopascals.
    Group 1 wastewater stream means a wastewater stream consisting of 
process wastewater as defined in this section at an existing or new 
source that meets the criteria for Group 1 status in Sec.  63.132(c) 
for table 9 compounds and/or a wastewater stream consisting of process 
wastewater at a new source that meets the criteria for Group 1 status 
in Sec.  63.132(d) for table 8 compounds.
    Group 2 process vent means, before July 15, 2027, a process vent 
for which the vent stream flow rate is less than 0.005 standard cubic 
meter per minute, the total organic HAP concentration is less than 50 
parts per million by volume or the total resource effectiveness index 
value, calculated according to Sec.  63.115, is greater than 1.0. On 
and after July 15, 2027, Group 2 process vent means a process vent that 
emits less than 1.0 pound per hour of total organic HAP.
    Group 2 storage vessel means a storage vessel that does not meet 
the definition of a Group 1 storage vessel.
    Group 2 transfer rack means a transfer rack that does not meet the 
definition of Group 1 transfer rack.
    Group 2 wastewater stream means any process wastewater stream that 
does not meet the definition of a Group 1 wastewater stream.
    Halogenated vent stream or halogenated stream means a vent stream 
from a process vent or transfer operation determined to have a mass 
emission rate of halogen atoms contained in organic compounds of 0.45 
kilograms per hour or greater determined by the procedures presented in 
Sec.  63.115(d)(2)(v).
    Halogens and hydrogen halides means hydrogen chloride (HCl), 
chlorine (Cl2), hydrogen bromide (HBr), bromine 
(Br2), and hydrogen fluoride (HF).
    Hard-piping means pipe or tubing that is manufactured and properly 
installed using good engineering judgment and standards such as 
American National Standards Institute (ANSI) B31-3 (see Sec.  63.14 for 
ANSI contact information).
    Heat exchange system means a device or collection of devices used 
to transfer heat from process fluids to water without intentional 
direct contact of the process fluid with the water (i.e., non-contact 
heat exchanger) and to transport and/or cool the water in a closed-loop 
recirculation system (cooling tower system) or a once-through system 
(e.g., river or pond water). For closed-loop recirculation systems, the 
heat exchange system consists of a cooling tower, all CMPU heat 
exchangers that are in organic HAP service, as defined in this subpart, 
serviced by that cooling tower, and all water lines to and from these 
process unit heat exchangers. For once-through systems, the heat 
exchange system consists of all heat exchangers that are in organic HAP 
service, as defined in this subpart, servicing an individual CMPU and 
all water lines to and from these heat exchangers. Sample coolers or 
pump seal coolers are not

[[Page 43158]]

considered heat exchangers for the purpose of this definition and are 
not part of the heat exchange system. Intentional direct contact with 
process fluids results in the formation of a wastewater.
    Impurity means a substance that is produced coincidentally with the 
primary product or is present in a raw material. An impurity does not 
serve a useful purpose in the production or use of the primary product 
and is not isolated.
    In ethylene oxide service means the following:
    (i) For equipment leaks, any equipment that contains or contacts a 
fluid (liquid or gas) that is at least 0.1 percent by weight of 
ethylene oxide. If information exists that suggests ethylene oxide 
could be present in equipment, the equipment is considered to be ``in 
ethylene oxide service'' unless the procedures specified in Sec.  
63.109 are performed to demonstrate that the equipment does not meet 
the definition of being ``in ethylene oxide service''. Examples of 
information that could suggest ethylene oxide could be present in 
equipment, include calculations based on safety data sheets, material 
balances, process stoichiometry, or previous test results provided the 
results are still relevant to the current operating conditions.
    (ii) For heat exchange systems, any heat exchange system in a 
process that cools process fluids (liquid or gas) that are 0.1 percent 
or greater by weight of ethylene oxide. If knowledge exists that 
suggests ethylene oxide could be present in a heat exchange system, 
then the heat exchange system is considered to be ``in ethylene oxide 
service'' unless the procedures specified in Sec.  63.109 are performed 
to demonstrate that the heat exchange system does not meet the 
definition of being ``in ethylene oxide service''. Examples of 
information that could suggest ethylene oxide could be present in a 
heat exchange system, include calculations based on safety data sheets, 
material balances, process stoichiometry, or previous test results 
provided the results are still relevant to the current operating 
conditions.
    (iii) For process vents, each Group 1 and Group 2 process vent in a 
process that, when uncontrolled, contains a concentration of greater 
than or equal to 1 ppmv undiluted ethylene oxide, and when combined, 
the sum of all these process vents within the process would emit 
uncontrolled, ethylene oxide emissions greater than or equal to 5 lb/yr 
(2.27 kg/yr). If information exists that suggests ethylene oxide could 
be present in a Group 1 or Group 2 process vent, then the Group 1 or 
Group 2 process vent is considered to be ``in ethylene oxide service'' 
unless an analysis is performed as specified in Sec.  63.109 to 
demonstrate that the Group 1 or Group 2 process vent does not meet the 
definition of being ``in ethylene oxide service''. Examples of 
information that could suggest ethylene oxide could be present in a 
Group 1 or Group 2 process vent, include calculations based on safety 
data sheets, material balances, process stoichiometry, or previous test 
results provided the results are still relevant to the current 
operating conditions.
    (iv) For storage vessels, storage vessels of any capacity and vapor 
pressure storing a liquid that is at least 0.1 percent by weight of 
ethylene oxide. If knowledge exists that suggests ethylene oxide could 
be present in a storage vessel, then the storage vessel is considered 
to be ``in ethylene oxide service'' unless the procedures specified in 
Sec.  63.109 are performed to demonstrate that the storage vessel does 
not meet the definition of being ``in ethylene oxide service''. The 
exemption for ``vessels storing organic liquids that contain organic 
hazardous air pollutants only as impurities'' listed in the definition 
of ``storage vessel'' in this section does not apply for storage 
vessels that may be in ethylene oxide service. Examples of information 
that could suggest ethylene oxide could be present in a storage vessel, 
include calculations based on safety data sheets, material balances, 
process stoichiometry, or previous test results provided the results 
are still relevant to the current operating conditions.
    (v) For wastewater streams, any wastewater stream that contains 
total annual average concentration of ethylene oxide greater than or 
equal to 1 parts per million by weight at any flow rate. If knowledge 
exists that suggests ethylene oxide could be present in a wastewater 
stream, then the wastewater stream is considered to be ``in ethylene 
oxide service'' unless sampling and analysis is performed as specified 
in Sec.  63.109 to demonstrate that the wastewater stream does not meet 
the definition of being ``in ethylene oxide service''. Examples of 
information that could suggest ethylene oxide could be present in a 
wastewater stream, include calculations based on safety data sheets, 
material balances, process stoichiometry, or previous test results 
provided the results are still relevant to the current operating 
conditions.
    In food/medical service means that a piece of equipment in organic 
hazardous air pollutant service contacts a process stream used to 
manufacture a Food and Drug Administration regulated product where 
leakage of a barrier fluid into the process stream would cause any of 
the following:
    (i) A dilution of product quality so that the product would not 
meet written specifications,
    (ii) An exothermic reaction which is a safety hazard,
    (iii) The intended reaction to be slowed down or stopped, or
    (iv) An undesired side reaction to occur.
    In gas/vapor service means that a piece of equipment in organic 
hazardous air pollutant service contains a gas or vapor at operating 
conditions.
    In heavy liquid service means that a piece of equipment in organic 
hazardous air pollutant service is not in gas/vapor service or in light 
liquid service.
    In light liquid service means that a piece of equipment in organic 
hazardous air pollutant service contains a liquid that meets the 
following conditions:
    (i) The vapor pressure of one or more of the organic compounds is 
greater than 0.3 kilopascals at 20 [deg]C,
    (ii) The total concentration of the pure organic compounds 
constituents having a vapor pressure greater than 0.3 kilopascals at 20 
[deg]C is equal to or greater than 20 percent by weight of the total 
process stream, and
    (iii) The fluid is a liquid at operating conditions.
    Note 1 to In light liquid service: Vapor pressures may be 
determined by the methods described in Sec.  60.485(e)(1) of this 
chapter.
    In liquid service means that a piece of equipment in organic 
hazardous air pollutant service is not in gas/vapor service.
    In organic hazardous air pollutant or in organic HAP service means 
that a piece of equipment or heat exchange system either contains or 
contacts a fluid (liquid or gas) that is at least 5 percent by weight 
of total organic HAP's as determined according to the provisions of 
Sec.  63.180(d). The provisions of Sec.  63.180(d) also specify how to 
determine that a piece of equipment is not in organic HAP service. For 
purposes of the definition of ``heat exchange system'', the term 
``equipment'' in Sec.  63.180(d) includes heat exchange systems.
    In vacuum service means that equipment is operating at an internal 
pressure which is at least 5 kilopascals below ambient pressure.
    In volatile organic compound or in VOC service means, for the 
purposes of subpart H of this part, that:
    (i) The piece of equipment contains or contacts a process fluid 
that is at least

[[Page 43159]]

10 percent VOC by weight (see Sec.  60.2 of this chapter for the 
definition of VOC, and Sec.  60.485(d) of this chapter to determine 
whether a piece of equipment is not in VOC service); and
    (ii) The piece of equipment is not in heavy liquid service as 
defined in Sec.  60.481 of this chapter.
    Incinerator means an enclosed combustion device that is used for 
destroying organic compounds. Auxiliary fuel may be used to heat waste 
gas to combustion temperatures. Any energy recovery section present is 
not physically formed into one manufactured or assembled unit with the 
combustion section; rather, the energy recovery section is a separate 
section following the combustion section and the two are joined by 
ducts or connections carrying flue gas. The above energy recovery 
section limitation does not apply to an energy recovery section used 
solely to preheat the incoming vent stream or combustion air.
    Individual drain system means the stationary system used to convey 
wastewater streams or residuals to a waste management unit or to 
discharge or disposal. The term includes hard-piping, all process 
drains and junction boxes, together with their associated sewer lines 
and other junction boxes, manholes, sumps, and lift stations, conveying 
wastewater streams or residuals. A segregated stormwater sewer system, 
which is a drain and collection system designed and operated for the 
sole purpose of collecting rainfall runoff at a facility, and which is 
segregated from all other individual drain systems, is excluded from 
this definition.
    Initial start-up means the first time a new or reconstructed source 
begins production, or, for equipment added or changed as described in 
Sec.  63.100(l) or (m), the first time the equipment is put into 
operation. Initial start-up does not include operation solely for 
testing equipment. For purposes of subpart G of this part, initial 
start-up does not include subsequent start-ups (as defined in this 
section) of chemical manufacturing process units following malfunctions 
or shutdowns or following changes in product for flexible operation 
units or following recharging of equipment in batch operation. For 
purposes of subpart H of this part, initial start-up does not include 
subsequent start-ups (as defined in this section) of process units (as 
defined in Sec.  this section) following malfunctions or process unit 
shutdowns.
    In-situ sampling systems means nonextractive samplers or in-line 
samplers.
    Instrumentation system means a group of equipment components used 
to condition and convey a sample of the process fluid to analyzers and 
instruments for the purpose of determining process operating conditions 
(e.g., composition, pressure, flow, etc.). Valves and connectors are 
the predominant type of equipment used in instrumentation systems; 
however, other types of equipment may also be included in these 
systems. Only valves nominally 0.5 inches and smaller, and connectors 
nominally 0.75 inches and smaller in diameter are considered 
instrumentation systems for the purposes of subpart H of this part. 
Valves greater than nominally 0.5 inches and connectors greater than 
nominally 0.75 inches associated with instrumentation systems are not 
considered part of instrumentation systems and must be monitored 
individually.
    Intermittent vapor processing system means a vapor processing 
system that employs an intermediate vapor holder to accumulate total 
organic compound vapors collected from tank trucks or railcars, and 
treats the accumulated vapors only during automatically controlled 
cycles.
    Internal floating roof means a cover that rests or floats on the 
liquid surface (but not necessarily in complete contact with it) inside 
a storage vessel or waste management unit that has a permanently 
affixed roof.
    Junction box means a manhole or access point to a wastewater sewer 
line or a lift station.
    Liquid-mounted seal means a foam- or liquid-filled seal mounted in 
contact with the liquid between the wall of the storage vessel or waste 
management unit and the floating roof. The seal is mounted continuously 
around the circumference of the vessel or unit.
    Liquids dripping means any visible leakage from the seal including 
dripping, spraying, misting, clouding, and ice formation. Indications 
of liquid dripping include puddling or new stains that are indicative 
of an existing evaporated drip.
    Loading cycle means the time period from the beginning of filling a 
tank truck or railcar until flow to the control device ceases, as 
measured by the flow indicator.
    Loading rack means a single system used to fill tank trucks and 
railcars at a single geographic site. Loading equipment and operations 
that are physically separate (i.e., do not share common piping, valves, 
and other equipment) are considered to be separate loading racks.
    Maintenance wastewater means wastewater generated by the draining 
of process fluid from components in the chemical manufacturing process 
unit into an individual drain system prior to or during maintenance 
activities. Maintenance wastewater can be generated during planned and 
unplanned shutdowns and during periods not associated with a shutdown. 
Examples of activities that can generate maintenance wastewaters 
include descaling of heat exchanger tubing bundles, cleaning of 
distillation column traps, draining of low legs and high point bleeds, 
draining of pumps into an individual drain system, and draining of 
portions of the chemical manufacturing process unit for repair.
    Maximum true vapor pressure means the equilibrium partial pressure 
exerted by the total organic HAP's in the stored or transferred liquid 
at the temperature equal to the highest calendar-month average of the 
liquid storage or transfer temperature for liquids stored or 
transferred above or below the ambient temperature or at the local 
maximum monthly average temperature as reported by the National Weather 
Service for liquids stored or transferred at the ambient temperature, 
as determined:
    (i) In accordance with methods described in API MPMS 19.2 
(incorporated by reference as specified in Sec.  63.14); or
    (ii) As obtained from standard reference texts; or
    (iii) As determined by the ASTM D2879-23 (incorporated by reference 
as specified in Sec.  63.14); or
    (iv) Any other method approved by the Administrator.
    Metallic shoe seal or mechanical shoe seal means metal sheets that 
are held vertically against the wall of the storage vessel by springs, 
weighted levers, or other mechanisms and connected to the floating roof 
by braces or other means. A flexible coated fabric (envelope) spans the 
annular space between the metal sheet and the floating roof.
    Non-automated monitoring and recording system means manual reading 
of values measured by monitoring instruments and manual transcription 
of those values to create a record. Non-automated systems do not 
include strip charts.
    Nonrepairable means that it is technically infeasible to repair a 
piece of equipment from which a leak has been detected without a 
process unit shutdown.
    Oil-water separator or organic-water separator means a waste 
management unit, generally a tank used to separate oil or organics from 
water. An oil-water

[[Page 43160]]

or organic-water separator consists of not only the separation unit but 
also the forebay and other separator basins, skimmers, weirs, grit 
chambers, sludge hoppers, and bar screens that are located directly 
after the individual drain system and prior to additional treatment 
units such as an air flotation unit, clarifier, or biological treatment 
unit. Examples of an oil-water or organic-water separator include, but 
are not limited to, an American Petroleum Institute separator, 
parallel-plate interceptor, and corrugated-plate interceptor with the 
associated ancillary equipment.
    On-site or On site means, with respect to records required to be 
maintained by this subpart, that the records are stored at a location 
within a major source which encompasses the affected source. On-site 
includes, but is not limited to, storage at the chemical manufacturing 
process unit to which the records pertain, or storage in central files 
elsewhere at the major source.
    Open biological treatment process means a biological treatment 
process that is not a closed biological treatment process as defined in 
this section.
    Open-ended valve or line means any valve, except pressure relief 
valves, having one side of the valve seat in contact with process fluid 
and one side open to atmosphere, either directly or through open 
piping.
    Operating permit means a permit required by 40 CFR part 70 or 71.
    Organic hazardous air pollutant or organic HAP means one of the 
chemicals listed in table 2 of this subpart.
    Organic monitoring device means a unit of equipment used to 
indicate the concentration level of organic compounds exiting a 
recovery device based on a detection principle such as infra-red, 
photoionization, or thermal conductivity.
    Petroleum refining process, also referred to as a petroleum 
refining process unit, means a process that for the purpose of 
producing transportation fuels (such as gasoline and diesel fuels), 
heating fuels (such as fuel gas, distillate, and residual fuel oils), 
or lubricants separates petroleum or separates, cracks, or reforms 
unfinished derivatives. Examples of such units include, but are not 
limited to, alkylation units, catalytic hydrotreating, catalytic 
hydrorefining, catalytic hydrocracking, catalytic reforming, catalytic 
cracking, crude distillation, and thermal processes.
    Plant site means all contiguous or adjoining property that is under 
common control, including properties that are separated only by a road 
or other public right-of-way. Common control includes properties that 
are owned, leased, or operated by the same entity, parent entity, 
subsidiary, or any combination thereof.
    Point of determination means each point where process wastewater 
exits the chemical manufacturing process unit. This subpart and subpart 
G of this part allows point of determination of the characteristics of 
a wastewater stream:
    (i) At the point of determination or
    (ii) Downstream of the point of determination if corrections are 
made for changes in flow rate and annual average concentration of table 
8 or table 9 compounds as determined in Sec.  63.144. Such changes 
include losses by air emissions; reduction of annual average 
concentration or changes in flow rate by mixing with other water or 
wastewater streams; and reduction in flow rate or annual average 
concentration by treating or otherwise handling the wastewater stream 
to remove or destroy hazardous air pollutants.
    Point of transfer means:
    (i) If the transfer is to an off-site location for control, the 
point where the conveyance crosses the property line; or
    (ii) If the transfer is to an on-site location not owned or 
operated by the owner or operator of the source, the point where the 
conveyance enters the operation or equipment of the transferee.
    Polymerizing monomer means a molecule or compound usually 
containing carbon and of relatively low molecular weight and simple 
structure (e.g., hydrogen cyanide, acrylonitrile, styrene), which is 
capable of conversion to polymers, synthetic resins, or elastomers by 
combination with itself due to heat generation caused by a pump 
mechanical seal surface, contamination by a seal fluid (e.g., organic 
peroxides or chemicals that will form organic peroxides), or a 
combination of both with the resultant polymer buildup causing rapid 
mechanical seal failure.
    Pressure release means the emission of materials resulting from the 
system pressure being greater than the set pressure of the pressure 
relief device. This release can be one release or a series of releases 
over a short time period.
    Pressure relief device or valve means a valve, rupture disk, or 
similar device used only to release an unplanned, nonroutine discharge 
of gas from process equipment in order to avoid safety hazards or 
equipment damage. A pressure relief device discharge can result from an 
operator error, a malfunction such as a power failure or equipment 
failure, or other unexpected cause. Such devices include conventional, 
spring-actuated relief valves, balanced bellows relief valves, pilot-
operated relief valves, rupture disks, and breaking, buckling, or 
shearing pin devices. Devices that are actuated either by a pressure of 
less than or equal to 2.5 pounds per square inch gauge or by a vacuum 
are not pressure relief devices.
    Pressure-assisted multi-point flare means a flare system consisting 
of multiple flare burners in staged arrays whereby the vent stream 
pressure is used to promote mixing and smokeless operation at the flare 
burner tips. Pressure-assisted multi-point flares are designed for 
smokeless operation at velocities up to Mach = 1 conditions (i.e., 
sonic conditions), can be elevated or at ground level, and typically 
use cross-lighting for flame propagation to combust any flare vent 
gases sent to a particular stage of flare burners.
    Pressure vessel means a storage vessel that is used to store 
liquids or gases and is designed not to vent to the atmosphere as a 
result of compression of the vapor headspace in the pressure vessel 
during filling of the pressure vessel to its design capacity.
    Primary fuel means the fuel that provides the principal heat input 
to the device. To be considered primary, the fuel must be able to 
sustain operation without the addition of other fuels.
    Process heater means a device that transfers heat liberated by 
burning fuel directly to process streams or to heat transfer liquids 
other than water.
    Process unit means a chemical manufacturing process unit as defined 
in subpart F of this part, a process subject to the provisions of 
subpart I of this part, or a process subject to another subpart in this 
part that references this subpart.
    Process unit shutdown means a work practice or operational 
procedure that stops production from a process unit or part of a 
process unit during which it is technically feasible to clear process 
material from a process unit or part of a process unit consistent with 
safety constraints and during which repairs can be effected. An 
unscheduled work practice or operational procedure that stops 
production from a process unit or part of a process unit for less than 
24 hours is not a process unit shutdown. An unscheduled work practice 
or operational procedure that would stop production from a process unit 
or part of a process unit for a shorter period of time than would be 
required to clear the process unit or part of the process unit of 
materials and start up the unit, and would result in greater emissions 
than delay of repair of leaking components until the next scheduled 
process unit

[[Page 43161]]

shutdown, is not a process unit shutdown. The use of spare equipment 
and technically feasible bypassing of equipment without stopping 
production are not process unit shutdowns.
    Process vent means the point of discharge to the atmosphere (or the 
point of entry into a control device, if any) of a gas stream if the 
gas stream has the characteristics specified in Sec.  63.107(b) through 
(h), or meets the criteria specified in Sec.  63.107(i). For purposes 
of Sec. Sec.  63.113 through 63.118, all references to the 
characteristics of a process vent (e.g., flow rate, total HAP 
concentration, or TRE index value) shall mean the characteristics of 
the gas stream.
    Process wastewater means wastewater which, during manufacturing or 
processing, comes into direct contact with or results from the 
production or use of any raw material, intermediate product, finished 
product, by-product, or waste product. Examples are product tank 
drawdown or feed tank drawdown; water formed during a chemical reaction 
or used as a reactant; water used to wash impurities from organic 
products or reactants; water used to cool or quench organic vapor 
streams through direct contact; and condensed steam from jet ejector 
systems pulling vacuum on vessels containing organics.
    Process wastewater stream means a stream that contains process 
wastewater.
    Product means a compound or chemical which is manufactured as the 
intended product of the chemical manufacturing process unit. By-
products, isolated intermediates, impurities, wastes, and trace 
contaminants are not considered products.
    Product separator means phase separators, flash drums, knock-out 
drums, decanters, degassers, and condenser(s) including ejector-
condenser(s) associated with a reactor or an air oxidation reactor.
    Product tank drawdown means any material or mixture of materials 
discharged from a product tank for the purpose of removing water or 
other contaminants from the product tank.
    Product tank, as used in the wastewater provisions, means a 
stationary unit that is designed to contain an accumulation of 
materials that are fed to or produced by a process unit, and is 
constructed primarily of non-earthen materials (e.g., wood, concrete, 
steel, plastic) which provide structural support. This term has the 
same meaning as a product storage vessel.
    Rack-weighted average partial pressure means the throughput 
weighted average of the average maximum true vapor pressure of liquids 
containing organic HAP transferred at a transfer rack. The rack-
weighted average partial pressure shall be calculated using the 
equation below:
Equation 1 to Paragraph (b) Rack-Weighted Average Partial Pressure
[GRAPHIC] [TIFF OMITTED] TR16MY24.053

Where:

P = Rack-weighted average partial pressure, kilopascals.
Pi = Individual HAP maximum true vapor pressure, 
kilopascals, = Xi*P, where Xi is the mole 
fraction of compound i in the liquid.
Gi = Yearly volume of each liquid that contains organic 
HAP that is transferred at the rack, liters.
I = Each liquid that contains HAP that is transferred at the rack.

    Reactor means a device or vessel in which one or more chemicals or 
reactants, other than air, are combined or decomposed in such a way 
that their molecular structures are altered and one or more new organic 
compounds are formed. Reactor includes the product separator and any 
associated vacuum pump or steam jet.
    Recapture device means an individual unit of equipment capable of 
and used for the purpose of recovering chemicals, but not normally for 
use, reuse, or sale. For example, a recapture device may recover 
chemicals primarily for disposal. Recapture devices include, but are 
not limited to, absorbers, carbon adsorbers, and condensers.
    Recovery device means an individual unit of equipment capable of 
and normally used for the purpose of recovering chemicals for fuel 
value (i.e., net positive heating value), use, reuse or for sale for 
fuel value, use, or reuse. Examples of equipment that may be recovery 
devices include absorbers, carbon adsorbers, condensers, oil-water 
separators or organic-water separators, or organic removal devices such 
as decanters, strippers, or thin-film evaporation units. For purposes 
of the monitoring, recordkeeping, and reporting requirements of 
subparts G and H of this part, recapture devices are considered 
recovery devices.
    Reference control technology for process vents means a combustion 
device or recapture device used to reduce organic hazardous air 
pollutant emissions by 98 percent, or to an outlet concentration of 20 
parts per million by volume.
    Reference control technology for storage vessels means an internal 
floating roof meeting the specifications of Sec.  63.119(b), an 
external floating roof meeting the specifications of Sec.  63.119(c), 
an external floating roof converted to an internal floating roof 
meeting the specifications of Sec.  63.119(d), or a closed-vent system 
to a control device achieving 95-percent reduction in organic HAP 
emissions. For purposes of emissions averaging, these four technologies 
are considered equivalent.
    Reference control technology for transfer racks means a combustion 
device, recapture device, or recovery device used to reduce organic 
hazardous air pollutants emissions by 98 percent, or to an outlet 
concentration of 20 parts per million by volume; or a vapor balancing 
system.
    Reference control technology for wastewater means the use of:
    (i) Controls specified in Sec. Sec.  63.133 through 63.137;
    (ii) A steam stripper meeting the specifications of Sec.  63.138(d) 
or any of the other alternative control measures specified in Sec.  
63.138(b), (c), (e), (f), (g), or (h); and
    (iii) A control device to reduce by 95 percent (or to an outlet 
concentration of 20 parts per million by volume for combustion devices 
or for noncombustion devices controlling air emissions from waste 
management units other than surface impoundments or containers) the 
organic hazardous air pollutants emissions in the vapor streams vented 
from wastewater tanks, oil-water separators, containers, surface 
impoundments, individual drain systems, and treatment processes 
(including the design steam stripper) managing wastewater.
    Relief valve means a type of pressure relief device that is 
designed to re-close after the pressure relief.
    Repaired means that equipment:
    (i) Is adjusted, or otherwise altered, to eliminate a leak as 
defined in the

[[Page 43162]]

applicable sections of subpart H of this part, and
    (ii) Unless otherwise specified in applicable provisions of subpart 
H of this part, is monitored as specified in Sec.  63.180(b) and (c), 
as appropriate, to verify that emissions from the equipment are below 
the applicable leak definition.
    Research and development facility means laboratory and pilot plant 
operations whose primary purpose is to conduct research and development 
into new processes and products, where the operations are under the 
close supervision of technically trained personnel, and is not engaged 
in the manufacture of products for commercial sale, except in a de 
minimis manner.
    Residual means any liquid or solid material containing table 9 
compounds that is removed from a wastewater stream by a waste 
management unit or treatment process that does not destroy organics 
(nondestructive unit). Examples of residuals from nondestructive 
wastewater management units are: the organic layer and bottom residue 
removed by a decanter or organic-water separator and the overheads from 
a steam stripper or air stripper. Examples of materials which are not 
residuals are: silt; mud; leaves; bottoms from a steam stripper or air 
stripper; and sludges, ash, or other materials removed from wastewater 
being treated by destructive devices such as biological treatment units 
and incinerators.
    Routed to a process or route to a process means the emissions are 
conveyed to any enclosed portion of a process unit where the emissions 
are predominately recycled and/or consumed in the same manner as a 
material that fulfills the same function in the process; and/or 
transformed by chemical reaction into materials that are not organic 
hazardous air pollutants; and/or incorporated into a product; and/or 
recovered.
    Sampling connection system means an assembly of equipment within a 
process unit used during periods of representative operation to take 
samples of the process fluid. Equipment used to take non-routine grab 
samples is not considered a sampling connection system.
    Screwed connector means a threaded pipe fitting where the threads 
are cut on the pipe wall and the fitting requires only two pieces to 
make the connection (i.e., the pipe and the fitting).
    Secondary fuel means a fuel fired through a burner other than the 
primary fuel burner that provides supplementary heat in addition to the 
heat provided by the primary fuel.
    Sensor means a device that measures a physical quantity or the 
change in a physical quantity, such as temperature, pressure, flow 
rate, pH, or liquid level.
    Set pressure means the pressure at which a properly operating 
pressure relief device begins to open to relieve atypical process 
system operating pressure.
    Sewer line means a lateral, trunk line, branch line, or other 
conduit including, but not limited to, grates, trenches, etc., used to 
convey wastewater streams or residuals to a downstream waste management 
unit.
    Shutdown means for purposes including, but not limited to, periodic 
maintenance, replacement of equipment, or repair, the cessation of 
operation of a chemical manufacturing process unit or a reactor, air 
oxidation reactor, distillation unit, waste management unit, equipment 
required or used to comply with this subpart, subpart G or H of this 
part, or the emptying and degassing of a storage vessel. Shutdown does 
not include the routine rinsing or washing of equipment in batch 
operation between batches.
    Simultaneous loading means, for a shared control device, loading of 
organic HAP materials from more than one transfer arm at the same time 
such that the beginning and ending times of loading cycles coincide or 
overlap and there is no interruption in vapor flow to the shared 
control device.
    Single-seal system means a floating roof having one continuous seal 
that completely covers the space between the wall of the storage vessel 
and the edge of the floating roof. This seal may be a vapor-mounted, 
liquid-mounted, or metallic shoe seal.
    Source means the collection of emission points to which this 
subpart applies as determined by the criteria in Sec.  63.100. For 
purposes of subparts F, G, and H of this part, the term affected source 
as used in subpart A of this part has the same meaning as the term 
source defined here.
    Specific gravity monitoring device means a unit of equipment used 
to monitor specific gravity and having a minimum accuracy of 0.02 specific gravity units.
    Start-up means the setting into operation of a chemical 
manufacturing process unit or a reactor, air oxidation reactor, 
distillation unit, waste management unit, or equipment required or used 
to comply with this subpart, subpart G or H of this part, or a storage 
vessel after emptying and degassing. Start-up includes initial start-
up, operation solely for testing equipment, the recharging of equipment 
in batch operation, and transitional conditions due to changes in 
product for flexible operation units.
    Start-up, shutdown, and malfunction plan means the plan required 
under Sec.  63.6(e)(3). This plan details the procedures for operation 
and maintenance of the source during periods of start-up, shutdown, and 
malfunction. For each source as defined in this section, this 
definition no longer applies on and after July 15, 2027.
    Steam jet ejector means a steam nozzle which discharges a high-
velocity jet across a suction chamber that is connected to the 
equipment to be evacuated.
    Storage vessel means a tank or other vessel that is used to store 
organic liquids that contain one or more of the organic HAP's listed in 
table 2 to this subpart and that has been assigned, according to the 
procedures in Sec.  63.100(g), to a chemical manufacturing process unit 
that is subject to this subpart. Storage vessel does not include:
    (i) Vessels permanently attached to motor vehicles such as trucks, 
railcars, barges, or ships;
    (ii) Vessels with capacities smaller than 38 cubic meters;
    (iii) Except for storage vessels in ethylene oxide service, vessels 
storing organic liquids that contain organic hazardous air pollutants 
only as impurities;
    (iv) Bottoms receiver tanks;
    (v) Surge control vessels; or
    (vi) Wastewater storage tanks. Wastewater storage tanks are covered 
under the wastewater provisions.
    Surface impoundment means a waste management unit which is a 
natural topographic depression, manmade excavation, or diked area 
formed primarily of earthen materials (although it may be lined with 
manmade materials), which is designed to hold an accumulation of liquid 
wastes or waste containing free liquids. A surface impoundment is used 
for the purpose of treating, storing, or disposing of wastewater or 
residuals, and is not an injection well. Examples of surface 
impoundments are equalization, settling, and aeration pits, ponds, and 
lagoons.
    Surge control vessel means feed drums, recycle drums, and 
intermediate vessels. Surge control vessels are used within a chemical 
manufacturing process unit when in-process storage, mixing, or 
management of flow rates or volumes is needed to assist in production 
of a product.
    Table 8 compound means a compound listed in table 8 to subpart G of 
this part.

[[Page 43163]]

    Table 9 compound means a compound listed in table 9 to subpart G of 
this part.
    Temperature monitoring device means a unit of equipment used to 
monitor temperature and having a minimum accuracy of (a) 1 
percent of the temperature being monitored expressed in degrees Celsius 
(([deg]C) or (b) 0.5 degrees ([deg]C), whichever is 
greater.
    The 33/50 program means a voluntary pollution prevention initiative 
established and administered by the EPA to encourage emissions 
reductions of 17 chemicals emitted in large volumes by industrial 
facilities. The EPA Document Number 741-K-92-001 provides more 
information about the 33/50 program.
    Total organic compounds (TOC), as used in the process vents 
provisions, means those compounds measured according to the procedures 
of Method 18 of appendix A-6 to 40 CFR part 60, ASTM D6420-18 
(incorporated by reference, see Sec.  63.14) may be used in lieu of 
Method 18, if the target compounds are all known and are all listed in 
Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 must not be 
used for methane and ethane; and ASTM D6420-18 may not be used as a 
total VOC method.
    Total resource effectiveness index value or TRE index value means a 
measure of the supplemental total resource requirement per unit 
reduction of organic HAP associated with a process vent stream, based 
on vent stream flow rate, emission rate of organic HAP, net heating 
value, and corrosion properties (whether or not the vent stream 
contains halogenated compounds), as quantified by the equations given 
under Sec.  63.115.
    Transfer operation means the loading, into a tank truck or railcar, 
of organic liquids that contain one or more of the organic hazardous 
air pollutants listed in table 2 of this subpart from a transfer rack 
(as defined in this section). Transfer operations do not include 
loading at an operating pressure greater than 204.9 kilopascals. For 
each source as defined in this section, the greater than 204.9 
kilopascals exemption in this definition no longer applies on and after 
July 15, 2027.
    Transfer rack means the collection of loading arms and loading 
hoses, at a single loading rack, that are assigned to a chemical 
manufacturing process unit subject to this subpart according to the 
procedures specified in Sec.  63.100(h) and are used to fill tank 
trucks and/or railcars with organic liquids that contain one or more of 
the organic hazardous air pollutants listed in table 2 to this subpart. 
Transfer rack includes the associated pumps, meters, shutoff valves, 
relief valves, and other piping and valves. Transfer rack does not 
include:
    (i) Racks, arms, or hoses that only transfer liquids containing 
organic hazardous air pollutants as impurities; or
    (ii) Racks, arms, or hoses that vapor balance during all loading 
operations.
    Treatment process means a specific technique that removes or 
destroys the organics in a wastewater or residual stream such as a 
steam stripping unit, thin-film evaporation unit, waste incinerator, 
biological treatment unit, or any other process applied to wastewater 
streams or residuals to comply with Sec.  63.138. Most treatment 
processes are conducted in tanks. Treatment processes are a subset of 
waste management units.
    Unit operation means one or more pieces of process equipment used 
to make a single change to the physical or chemical characteristics of 
one or more process streams. Unit operations include, but are not 
limited to, reactors, distillation units, extraction columns, 
absorbers, decanters, dryers, condensers, and filtration equipment.
    Vapor balancing system means a piping system that is designed to 
collect organic hazardous air pollutants vapors displaced from tank 
trucks or railcars during loading; and to route the collected organic 
hazardous air pollutants vapors to the storage vessel from which the 
liquid being loaded originated, or to another storage vessel connected 
by a common header or to compress and route to a process or a fuel gas 
system the collected organic hazardous air pollutants vapors.
    Vapor collection system, as used in the transfer provisions, means 
the equipment used to collect and transport organic HAP vapors 
displaced during the loading of tank trucks or railcars. This does not 
include the vapor collection system that is part of any tank truck or 
railcar vapor collection manifold system.
    Vapor-mounted seal means a continuous seal that completely covers 
the annular space between the wall of the storage vessel or waste 
management unit and the edge of the floating roof and is mounted such 
that there is a vapor space between the stored liquid and the bottom of 
the seal.
    Vent stream, as used in the process vent provisions, means the gas 
stream flowing through the process vent.
    Waste management unit means the equipment, structure(s), and/or 
device(s) used to convey, store, treat, or dispose of wastewater 
streams or residuals. Examples of waste management units include: 
Wastewater tanks, surface impoundments, individual drain systems, and 
biological wastewater treatment units. Examples of equipment that may 
be waste management units include containers, air flotation units, oil-
water separators or organic-water separators, or organic removal 
devices such as decanters, strippers, or thin-film evaporation units. 
If such equipment is used for recovery then it is part of a chemical 
manufacturing process unit and is not a waste management unit.
    Wastewater means water that:
    (i) Contains either:
    (A) An annual average concentration of table 9 compounds of at 
least 5 parts per million by weight and has an annual average flow rate 
of 0.02 liter per minute or greater, or
    (B) An annual average concentration of table 9 compounds of at 
least 10,000 parts per million by weight at any flow rate, and that
    (ii) Is discarded from a chemical manufacturing process unit that 
meets all of the criteria specified in Sec.  63.100 (b)(1) through (3). 
Wastewater is process wastewater or maintenance wastewater.
    Wastewater stream means a stream that contains only wastewater.
    Wastewater tank means a stationary waste management unit that is 
designed to contain an accumulation of wastewater or residuals and is 
constructed primarily of non-earthen materials (e.g., wood, concrete, 
steel, plastic) which provide structural support. Wastewater tanks used 
for flow equalization are included in this definition.
    Water seal controls means a seal pot, p-leg trap, or other type of 
trap filled with water (e.g., flooded sewers that maintain water levels 
adequate to prevent air flow through the system) that creates a water 
barrier between the sewer line and the atmosphere. The water level of 
the seal must be maintained in the vertical leg of a drain in order to 
be considered a water seal.

0
45. Revise and republish Sec.  63.102 to read as follows:


Sec.  63.102  General standards.

    (a) Except as specified in paragraph (e) of this section, owners 
and operators of sources subject to this subpart shall comply with the 
requirements of subparts G and H of this part as specified in 
paragraphs (a)(1) through (4) of this section.
    (1) The provisions set forth in this subpart and subpart G of this 
part shall apply at all times except during periods of start-up or 
shutdown (as defined in Sec.  63.101 of this subpart), malfunction, or 
non-operation of the chemical

[[Page 43164]]

manufacturing process unit (or specific portion thereof) resulting in 
cessation of the emissions to which this subpart and subpart G of this 
part apply. However, if a start-up, shutdown, malfunction or period of 
non-operation of one portion of a chemical manufacturing process unit 
does not affect the ability of a particular emission point to comply 
with the specific provisions to which it is subject, then that emission 
point shall still be required to comply with the applicable provisions 
of this subpart and subpart G of this part during the start-up, 
shutdown, malfunction or period of non-operation. For example, if there 
is an overpressure in the reactor area, a storage vessel in the 
chemical manufacturing process unit would still be required to be 
controlled in accordance with Sec.  63.119. Similarly, the degassing of 
a storage vessel would not affect the ability of a process vent to meet 
the requirements of Sec.  63.113.
    (2) The provisions set forth in subpart H of this part shall apply 
at all times except during periods of start-up or shutdown, 
malfunction, or process unit shutdown (as defined in Sec.  63.101(b)), 
or non-operation of the chemical manufacturing process unit (or 
specific portion thereof) in which the lines are drained and 
depressurized resulting in cessation of the emissions to which subpart 
H of this part applies.
    (3) The owner or operator shall not shut down items of equipment 
that are required or utilized for compliance with the provisions of 
this subpart or subpart G or H of this part during times when emissions 
(or, where applicable, wastewater streams or residuals) are being 
routed to such items of equipment, if the shutdown would contravene 
requirements of this subpart or subpart G or H of this part applicable 
to such items of equipment. This paragraph does not apply if the item 
of equipment is malfunctioning, or if the owner or operator must shut 
down the equipment to avoid damage due to a contemporaneous start-up, 
shutdown, or malfunction of the chemical manufacturing process unit or 
portion thereof.
    (4) During start-ups, shutdowns, and malfunctions when the 
requirements of this subpart and subparts G and/or H of this part do 
not apply pursuant to paragraphs (a)(1) through (3) of this section, 
the owner or operator shall implement, to the extent reasonably 
available, measures to prevent or minimize excess emissions to the 
extent practical. The general duty to minimize emissions during a 
period of startup, shutdown, or malfunction does not require the owner 
or operator to achieve emission levels that would be required by the 
applicable standard at other times if this is not consistent with 
safety and good air pollution control practices, nor does it require 
the owner or operator to make any further efforts to reduce emissions 
if levels required by the applicable standard have been achieved. 
Determination of whether such operation and maintenance procedures are 
being used will be based on information available to the Administrator 
which may include, but is not limited to, monitoring results, review of 
operation and maintenance procedures (including the startup, shutdown, 
and malfunction plan required in Sec.  63.6(e)(3)), review of operation 
and maintenance records, and inspection of the source. The measures to 
be taken may include, but are not limited to, air pollution control 
technologies, recovery technologies, work practices, pollution 
prevention, monitoring, and/or changes in the manner of operation of 
the source. Back-up control devices are not required but may be used if 
available.
    (b) If, in the judgment of the Administrator, an alternative means 
of emission limitation will achieve a reduction in organic HAP 
emissions at least equivalent to the reduction in organic HAP emissions 
from that source achieved under any design, equipment, work practice, 
or operational standards in subpart G or H of this part, the 
Administrator will publish in the Federal Register a notice permitting 
the use of the alternative means for purposes of compliance with that 
requirement.
    (1) The notice may condition the permission on requirements related 
to the operation and maintenance of the alternative means.
    (2) Any notice under this paragraph (b) shall be published only 
after public notice and an opportunity for a hearing.
    (3) Any person seeking permission to use an alternative means of 
compliance under this section shall collect, verify, and submit to the 
Administrator information showing that the alternative means achieves 
equivalent emission reductions.
    (c) Each owner or operator of a source subject to this subpart 
shall obtain a permit under 40 CFR part 70 or part 71 from the 
appropriate permitting authority by the date determined by 40 CFR part 
70 or part 71, as appropriate.
    (1) If the EPA has approved a State operating permit program under 
40 CFR part 70, the permit shall be obtained from the State authority. 
If the State operating permit program has not been approved, the source 
shall apply to the EPA Regional Office.
    (2) [Reserved]
    (d) The requirements in this subpart and subparts G and H of this 
part are federally enforceable under section 112 of the Act on and 
after the dates specified in Sec.  63.100(k) of this subpart.
    (e) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraph 
(a) of this section does not apply. Instead, owners and operators of 
sources as defined in Sec.  63.101 shall comply with the requirements 
in this subpart and subparts G and H of this part at all times, except 
during periods of nonoperation of the source (or specific portion 
thereof) resulting in cessation of the emissions to which this subpart 
or subpart G or H of this part applies.
    (f) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), at all 
times, owners and operators must operate and maintain any source, 
including associated air pollution control equipment and monitoring 
equipment, in a manner consistent with safety and good air pollution 
control practices for minimizing emissions. The general duty to 
minimize emissions does not require owners and operators to make any 
further efforts to reduce emissions if levels required by the 
applicable standard have been achieved. Determination of whether a 
source is operating in compliance with operation and maintenance 
requirements will be based on information available to the 
Administrator which may include, but is not limited to, monitoring 
results, review of operation and maintenance procedures, review of 
operation and maintenance records, and inspection of the source.

0
46. Amend Sec.  63.103 by revising paragraphs (b) introductory text, 
(b)(1) and (3), adding paragraph (b)(3)(ii), revising and republishing 
paragraphs (c)(2) and (3), and revising paragraphs (d) through (h) to 
read as follows:


Sec.  63.103  General compliance, reporting, and recordkeeping 
provisions.

* * * * *
    (b) Performance tests and initial compliance determinations shall 
be required only as specified in subparts G and H of this part.
    (1) Initial performance tests and compliance determinations shall 
be conducted according to the schedule and procedures in Sec.  63.7(a) 
and the applicable sections of subparts G and H of this part. Beginning 
no later than the compliance dates specified in Sec.  63.100(k)(10), 
except as outlined in subpart H of this part, conduct subsequent 
performance tests no later

[[Page 43165]]

than 60 calendar months after the previous performance test.
* * * * *
    (3) Performance tests shall be conducted as specified in paragraph 
(b)(3)(i) or (ii) of this section.
    (i) Except as specified in paragraph (b)(3)(ii) of this section, 
performance tests shall be conducted according to the provisions of 
Sec.  63.7(e), except that performance tests shall be conducted at 
maximum representative operating conditions for the process. During the 
performance test, an owner or operator may operate the control or 
recovery device at maximum or minimum representative operating 
conditions for monitored control or recovery device parameters, 
whichever results in lower emission reduction.
    (ii) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraph 
(b)(3)(i) of this section no longer applies and instead the owner or 
operator may not conduct performance tests during periods of 
malfunction. Owners and operators must record the process information 
that is necessary to document operating conditions during the test and 
include in such record an explanation to support that such conditions 
represent normal operation. Upon request, owners and operators must 
make available to the Administrator such records as may be necessary to 
determine the conditions of performance tests.
* * * * *
    (c) * * *
    (2) The owner or operator subject to subparts F, G, and H of this 
part shall keep the records specified in this paragraph, as well as 
records specified in subparts G and H.
    (i) Records of the occurrence and duration of each start-up, 
shutdown, and malfunction of operation of process equipment or of air 
pollution control equipment or continuous monitoring systems used to 
comply with this subpart or subpart G or H of this part during which 
excess emissions (as defined in Sec.  63.102(a)(4)) occur. For each 
source as defined in Sec.  63.101, on and after July 15, 2027, this 
paragraph (c)(2)(i) no longer applies; however, for historical 
compliance purposes, a copy of these records must be retained and 
available on-site for at least five years after the date of occurrence.
    (ii) For each start-up, shutdown, and malfunction during which 
excess emissions (as defined in Sec.  63.102(a)(4)) occur, records that 
the procedures specified in the source's start-up, shutdown, and 
malfunction plan were followed, and documentation of actions taken that 
are not consistent with the plan. For example, if a start-up, shutdown, 
and malfunction plan includes procedures for routing a control device 
to a backup control device (e.g., the incinerator for a halogenated 
stream could be routed to a flare during periods when the primary 
control device is out of service), records must be kept of whether the 
plan was followed. These records may take the form of a ``checklist,'' 
or other form of recordkeeping that confirms conformance with the 
start-up, shutdown, and malfunction plan for the event. For each source 
as defined in Sec.  63.101, on and after July 15, 2027, this paragraph 
(c)(2)(ii) no longer applies; however, for historical compliance 
purposes, a copy of the plan and these records must be retained and 
available on-site for 5 years after July 15, 2027.
    (iii) For continuous monitoring systems used to comply with subpart 
G of this part, records documenting the completion of calibration 
checks and maintenance of continuous monitoring systems that are 
specified in the manufacturer's instructions or other written 
procedures that provide adequate assurance that the equipment would 
reasonably be expected to monitor accurately.
    (iv) Beginning no later than the compliance dates specified in 
Sec.  63.100(k)(10), the manufacturer's specifications specified in 
paragraph (c)(2)(iii) of this section must include a schedule for 
calibrations, preventative maintenance procedures, a schedule for 
preventative maintenance, and corrective actions to be taken if a 
calibration fails. If a continuous monitoring system calibration fails, 
the continuous monitoring system is considered to be inoperative until 
the owner or operator takes corrective action and the system passes 
calibration. The owner or operator must record the nature and cause of 
instances when the continuous monitoring system is inoperative and the 
corrective action taken.
    (3) Records of start-up, shutdown and malfunction and continuous 
monitoring system calibration and maintenance are not required if they 
pertain solely to Group 2 emission points, as defined in Sec.  63.101, 
that are not included in an emissions average. For each source as 
defined in Sec.  63.101, on and after July 15, 2027, the phrase 
``start-up, shutdown and malfunction and'' in this paragraph (c)(3) no 
longer applies.
    (d) Unless required to be submitted electronically via the EPA's 
CEDRI, all reports required under this subpart and subparts G and H of 
this part must be sent to the Administrator at the addresses listed in 
Sec.  63.13, except that requests for permission to use an alternative 
means of compliance as provided for in Sec.  63.102(b) of this subpart 
and application for approval of a nominal efficiency as provided for in 
Sec.  63.150 (i)(1) through (6) must be submitted to the Director of 
the EPA Office of Air Quality Planning and Standards rather than to the 
Administrator or delegated authority.
    (1) Wherever subpart A of this part specifies ``postmark'' dates, 
submittals may be sent by methods other than the U.S. Mail (e.g., by 
fax or courier). Submittals shall be sent on or before the specified 
date.
    (2) If acceptable to both the Administrator and the owner or 
operator of a source, reports may be submitted on electronic media.
    (e) The owner or operator of a chemical manufacturing process unit 
which meets the criteria of Sec.  63.100(b)(1) and (3), but not the 
criteria of Sec.  63.100(b)(2), shall comply with the requirements of 
either paragraph (e)(1) or (2) of this section.
    (1) Retain information, data, and analysis used to determine that 
the chemical manufacturing process unit does not use as a reactant or 
manufacture as a product or co-product any organic hazardous air 
pollutant. Examples of information that could document this include, 
but are not limited to, records of chemicals purchased for the process, 
analyses of process stream composition, engineering calculations, or 
process knowledge.
    (2) When requested by the Administrator, demonstrate that the 
chemical manufacturing process unit does not use as a reactant or 
manufacture as a product or co-product any organic hazardous air 
pollutant.
    (f) To qualify for the exemption specified in Sec.  63.100(b)(4), 
the owner or operator shall maintain the documentation of the 
information required pursuant to Sec.  63.100(b)(4)(i), and 
documentation of any update of this information requested by the EPA 
Regional Office, and shall provide the documentation to the EPA 
Regional Office upon request. The EPA Regional Office will notify the 
owner or operator, after reviewing such documentation, if the source 
does not qualify for the exemption specified in Sec.  63.100(b)(4). In 
such cases, compliance with subpart H shall be required no later than 
90 days after expiration of the applicable compliance date in Sec.  
63.100(k)(3), but in no event earlier than 90 days after the date of 
such notification by the EPA Regional Office. Compliance with this

[[Page 43166]]

subpart and subpart G of this part shall be no later than April 22, 
1997, or as otherwise specified in Sec.  63.100(k)(2)(ii), unless an 
extension has been granted by the EPA Regional Office or permitting 
authority as provided in Sec.  63.6(i).
    (g) An owner or operator who elects to use the compliance extension 
provisions of Sec.  63.100(k)(6)(i) or (ii) shall submit a compliance 
extension request to the appropriate EPA Regional Office no later than 
45 days before the applicable compliance date in Sec.  63.100(k)(3), 
but in no event is submittal required earlier than May 10, 1995. The 
request shall contain the information specified in Sec.  
63.100(k)(5)(iv) and the reason compliance cannot reasonably be 
achieved without a process unit shutdown, as defined in 40 CFR 63.101 
or without replacement of the compressor or recasting of the distance 
piece.
    (h) An owner or operator who elects to use the compliance extension 
provisions of Sec.  63.100(k)(8) shall submit to the appropriate EPA 
Regional Office a brief description of the process change, identify the 
HAP eliminated, and the expected date of cessation of use or production 
of HAP. The description shall be submitted no later than May 10, 1995, 
or with the Notice of Compliance Status as required in Sec.  63.182(c), 
whichever is later.

0
47. Amend Sec.  63.104 by revising paragraphs (a) and (f) and adding 
paragraphs (g) through (l) to read as follows:


Sec.  63.104  Heat exchange system requirements.

    (a) Unless one or more of the conditions specified in paragraphs 
(a)(1) through (6) or paragraph (l) of this section are met, owners and 
operators of sources subject to this subpart shall monitor each heat 
exchange system used to cool process equipment in a chemical 
manufacturing process unit meeting the conditions of Sec.  63.100(b)(1) 
through (3), except for chemical manufacturing process units meeting 
the condition specified in Sec.  63.100(c), according to the provisions 
in either paragraph (b) or (c) of this section, and if applicable, 
paragraph (g) of this section. Whenever a leak is detected, the owner 
or operator shall comply with the requirements in paragraph (d) of this 
section, and if applicable, paragraphs (h) through (j) of this section. 
Owners and operators of heat exchange systems in a chemical 
manufacturing process unit meeting the conditions of Sec.  63.100(b)(1) 
through (3) must also comply with paragraph (k) of this section.
    (1) The heat exchange system is operated with the minimum pressure 
on the cooling water side at least 35 kilopascals greater than the 
maximum pressure on the process side.
    (2) There is an intervening cooling fluid, containing less than 5 
percent by weight of total hazardous air pollutants listed in table 4 
of this subpart, between the process and the cooling water. This 
intervening fluid serves to isolate the cooling water from the process 
fluid and the intervening fluid is not sent through a cooling tower or 
discharged. For purposes of this section, discharge does not include 
emptying for maintenance purposes.
    (3) The once-through heat exchange system is subject to a National 
Pollution Discharge Elimination System (NPDES) permit with an allowable 
discharge limit of 1 part per million or less above influent 
concentration or 10 percent or less above influent concentration, 
whichever is greater. For each source as defined in Sec.  63.101, 
beginning no later than the compliance dates specified in Sec.  
63.100(k)(10), this paragraph (a)(3) no longer applies.
    (4) Except as specified in paragraph (a)(4)(v) of this section, the 
once-through heat exchange system is subject to an NPDES permit that:
    (i) Requires monitoring of a parameter(s) or condition(s) to detect 
a leak of process fluids into cooling water;
    (ii) Specifies or includes the normal range of the parameter or 
condition;
    (iii) Requires monitoring for the parameters selected as leak 
indicators no less frequently than monthly for the first six months and 
quarterly thereafter; and
    (iv) Requires the owner or operator to report and correct leaks to 
the cooling water when the parameter or condition exceeds the normal 
range.
    (v) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), this 
paragraph (a)(4) no longer applies.
* * * * *
    (f)(1) Required records. The owner or operator shall retain the 
records identified in paragraphs (f)(1)(i) through (iv) of this 
section, and if applicable, paragraph (f)(3) of this section, as 
specified in Sec.  63.103(c)(1).
    (i) Monitoring data required by this section indicating a leak and 
the date when the leak was detected, and if demonstrated not to be a 
leak, the basis for that determination;
    (ii) Records of any leaks detected by procedures subject to 
paragraph (c)(2) of this section and the date the leak was discovered;
    (iii) The dates of efforts to repair leaks; and
    (iv) The method or procedure used to confirm repair of a leak and 
the date repair was confirmed.
    (2) Reports. If an owner or operator invokes the delay of repair 
provisions for a heat exchange system, the following information shall 
be submitted in the next semi-annual periodic report required by Sec.  
63.152(c). If the leak remains unrepaired, the information shall also 
be submitted in each subsequent periodic report, until repair of the 
leak is reported. In addition, if an owner or operator is complying 
with paragraph (g) or (l) of this section, then the semi-annual 
periodic report must include the information specified in paragraph 
(f)(2)(vi) of this section.
    (i) The owner or operator shall report the presence of the leak by 
identifying the heat exchange system and the date that the leak was 
detected.
    (ii) The owner or operator shall report whether or not the leak has 
been repaired.
    (iii) The owner or operator shall report the reason(s) for delay of 
repair. If delay of repair is invoked due to the reasons described in 
paragraph (e)(2) of this section, documentation of emissions estimates 
must also be submitted.
    (iv) If the leak remains unrepaired, the owner or operator shall 
report the expected date of repair.
    (v) If the leak is repaired, the owner or operator shall report the 
date the leak was successfully repaired.
    (vi) For each heat exchange system subject to paragraph (g) or (l) 
of this section, the following information must be submitted in each 
semi-annual periodic report required by Sec.  63.152(c).
    (A) The number of heat exchange systems at the plant site subject 
to the monitoring requirements in paragraph (g) or (l) of this section 
during the reporting period.
    (B) The number of heat exchange systems subject to the monitoring 
requirements in paragraph (g) or (l) of this section at the plant site 
found to be leaking during the reporting period.
    (C) For each monitoring location where a leak was identified during 
the reporting period, identification of the monitoring location (e.g., 
unique monitoring location or heat exchange system ID number), the 
measured total strippable hydrocarbon concentration (in ppmv as 
methane) or total hydrocarbon mass emissions rate (in kg/hr as methane) 
(if complying with paragraph (g) of this section) or the measured 
concentration of the monitored substance(s) (in ppmv) (if

[[Page 43167]]

complying with paragraph (l) of this section), the date the leak was 
first identified, and, if applicable, the date the source of the leak 
was identified;
    (D) For leaks that were repaired during the reporting period 
(including delayed repairs), identification of the monitoring location 
associated with the repaired leak, the total strippable hydrocarbon 
concentration or total hydrocarbon mass emissions rate (if complying 
with paragraph (g) of this section) or the measured concentration of 
the monitored substance(s) (if complying with paragraph (l) of this 
section) measured during re-monitoring to verify repair, and the re-
monitoring date (i.e., the effective date of repair); and
    (E) For each delayed repair, identification of the monitoring 
location associated with the leak for which repair is delayed, the date 
when the delay of repair began, the date the repair was completed or is 
expected to be completed (if the leak is not repaired during the 
reporting period), the total strippable hydrocarbon concentration or 
total hydrocarbon mass emissions rate (if complying with paragraph (g) 
of this section) or the measured concentration of the monitored 
substance(s) (if complying with paragraph (l) of this section) and date 
of each monitoring event conducted on the delayed repair during the 
reporting period, and an estimate in pounds of the potential total 
hydrocarbon emissions or monitored substance(s) emissions over the 
reporting period associated with the delayed repair.
    (3) Additional records. For each heat exchange system subject to 
paragraph (g) or (l) of this section, owners and operators must also 
keep records in paragraphs (f)(3)(i) through (iv) of this section.
    (i) Monitoring data required by paragraph (g) or (l) of this 
section that indicate a leak, the date the leak was detected, or, if 
applicable, the basis for determining there is no leak.
    (ii) The dates of efforts to repair leaks.
    (iii) The method or procedures used to confirm repair of a leak and 
the date the repair was confirmed.
    (iv) Documentation of delay of repair as specified in paragraphs 
(f)(3)(iv)(A) through (f)(3)(iv)(D) of this section.
    (A) The reason(s) for delaying repair.
    (B) A schedule for completing the repair as soon as practical.
    (C) The date and concentration or mass emissions rate of the leak 
as first identified and the results of all subsequent monitoring events 
during the delay of repair.
    (D) An estimate of the potential total hydrocarbon emissions (if 
monitoring the cooling water for leaks according to paragraph (g)(1) of 
this section) or monitored substance(s) emissions (if monitoring the 
cooling water for leaks according to paragraph (l) of this section) 
from the leaking heat exchange system or heat exchanger for each 
required delay of repair monitoring interval following the procedures 
in paragraphs (f)(3)(iv)(D)(1) through (4) of this section.
    (1) If an owner or operator complies with the total strippable 
hydrocarbon concentration leak action level, as specified in paragraph 
(g)(4) of this section, then the owner or operator must calculate the 
mass emissions rate by complying with the requirements of paragraph 
(g)(3)(ii) of this section or by determining the mass flow rate of the 
cooling water at the monitoring location where the leak was detected. 
If the monitoring location is an individual cooling tower riser, 
determine the total cooling water mass flow rate to the cooling tower. 
Cooling water mass flow rates may be determined using direct 
measurement, pump curves, heat balance calculations, or other 
engineering methods. If an owner or operator determines the mass flow 
rate of the cooling water, calculate the mass emissions rate by 
converting the stripping gas leak concentration (in ppmv as methane) to 
an equivalent liquid concentration, in parts per million by weight 
(ppmw), using equation 7-1 from ``Air Stripping Method (Modified El 
Paso Method) for Determination of Volatile Organic Compound Emissions 
from Water Sources'' (incorporated by reference--see Sec.  63.14) and 
multiply the equivalent liquid concentration by the mass flow rate of 
the cooling water.
    (2) For delay of repair monitoring intervals prior to repair of the 
leak, calculate the potential total hydrocarbon emissions or monitored 
substance(s) emissions for the leaking heat exchange system or heat 
exchanger for the monitoring interval by multiplying the mass emissions 
rate, determined in paragraph (g)(3)(ii) or (f)(3)(iv)(D)(1) or (4) of 
this section, by the duration of the delay of repair monitoring 
interval. The duration of the delay of repair monitoring interval is 
the time period starting at midnight on the day of the previous 
monitoring event or at midnight on the day the repair would have had to 
be completed if the repair had not been delayed, whichever is later, 
and ending at midnight of the day the of the current monitoring event.
    (3) For delay of repair monitoring intervals ending with a repaired 
leak, calculate the potential total hydrocarbon emissions or monitored 
substance(s) emissions for the leaking heat exchange system or heat 
exchanger for the final delay of repair monitoring interval by 
multiplying the duration of the final delay of repair monitoring 
interval by the mass emissions rate determined for the last monitoring 
event prior to the re-monitoring event used to verify the leak was 
repaired. The duration of the final delay of repair monitoring interval 
is the time period starting at midnight of the day of the last 
monitoring event prior to re-monitoring to verify the leak was repaired 
and ending at the time of the re-monitoring event that verified that 
the leak was repaired.
    (4) If an owner or operator monitors the cooling water for leaks 
according to paragraph (l) of this section, then the owner or operator 
must calculate the mass emissions rate by determining the mass flow 
rate of the cooling water at the monitoring location where the leak was 
detected. Cooling water mass flow rates may be determined using direct 
measurement, pump curves, heat balance calculations, or other 
engineering methods. Once determined, multiply the mass flow rate of 
the cooling water by the concentration of the measured substance(s).
    (g) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), owners and 
operators must monitor the cooling water for the presence of total 
strippable hydrocarbons that indicate a leak according to paragraph 
(g)(1) of this section, and if an owner or operator detects a leak 
pursuant to the procedures in this paragraph, then the owner or 
operator must repair it according to paragraphs (h) and (i) of this 
section, unless repair is delayed according to paragraph (j) of this 
section. The requirements in this paragraph do not apply to heat 
exchange systems that have a maximum cooling water flow rate of 10 
gallons per minute or less.
    (1) For each recirculating heat exchange system subject to the 
requirements of paragraph (g) of this section, owners and operators 
must collect and analyze a sample from the location(s) described in 
either paragraph (g)(1)(i) or (ii) of this section.
    (i) Each cooling tower return line or any representative riser 
within the cooling tower prior to exposure to air for each heat 
exchange system.
    (ii) Selected heat exchanger exit line(s), so that each heat 
exchanger or group of heat exchangers within a heat exchange system is 
covered by the selected monitoring location(s).
    (2) For each once-through heat exchange system, owners and 
operators

[[Page 43168]]

must collect and analyze a sample from the location(s) described in 
paragraph (g)(2)(i) of this section. The owner or operator may also 
elect to collect and analyze an additional sample from the location(s) 
described in paragraph (g)(2)(ii) of this section.
    (i) Selected heat exchanger exit line(s), so that each heat 
exchanger or group of heat exchangers within a heat exchange system is 
covered by the selected monitoring location(s). The selected monitoring 
location may be at a point where discharges from multiple heat exchange 
systems are combined provided that the combined cooling water flow rate 
at the monitoring location does not exceed 40,000 gallons per minute.
    (ii) The inlet water feed line for a once-through heat exchange 
system prior to any heat exchanger. If multiple heat exchange systems 
use the same water feed (i.e., inlet water from the same primary water 
source), the owner or operator may monitor at one representative 
location and use the monitoring results for that sampling location for 
all heat exchange systems that use that same water feed.
    (3) If an owner or operator complies with the total strippable 
hydrocarbon concentration leak action level as specified in paragraph 
(g)(4) of this section, then the owner or operator must comply with the 
requirements in paragraph (g)(3)(i) of this section. If an owner or 
operator complies with the total hydrocarbon mass emissions rate leak 
action level as specified in paragraph (g)(4) of this section, then the 
owner or operator must comply with the requirements in paragraphs 
(g)(3)(i) and (ii) of this section.
    (i) Owners and operators must determine the total strippable 
hydrocarbon concentration (in parts per million by volume (ppmv) as 
methane) at each monitoring location using the ``Air Stripping Method 
(Modified El Paso Method) for Determination of Volatile Organic 
Compound Emissions from Water Sources'' (incorporated by reference--see 
Sec.  63.14) using a flame ionization detector (FID) analyzer for on-
site determination as described in Section 6.1 of the Modified El Paso 
Method.
    (ii) Owners and operators must convert the total strippable 
hydrocarbon concentration (in ppmv as methane) to a total hydrocarbon 
mass emissions rate (as methane) using the calculations in Section 7.0 
of ``Air Stripping Method (Modified El Paso Method) for Determination 
of Volatile Organic Compound Emissions from Water Sources'' 
(incorporated by reference--see Sec.  63.14).
    (4) Except as specified in paragraph (g)(6) of this section, for 
each heat exchange system, owners and operators must initially monitor 
monthly for 6-months beginning upon startup and monitor quarterly 
thereafter using a leak action level defined as a total strippable 
hydrocarbon concentration (as methane) in the stripping gas of 6.2 ppmv 
or, for heat exchange systems with a recirculation rate of 10,000 
gallons per minute or less, the owner or operator may monitor quarterly 
using a leak action level defined as a total hydrocarbon mass emissions 
rate from the heat exchange system (as methane) of 0.18 kg/hr. If a 
leak is detected as specified in paragraph (g)(5) of this section, then 
owners and operators must monitor monthly until the leak has been 
repaired according to the requirements in paragraph (h) or (i) of this 
section. Once the leak has been repaired according to the requirements 
in paragraph (h) or (i) of this section, quarterly monitoring for the 
heat exchange system may resume. The monitoring frequencies specified 
in this paragraph also apply to the inlet water feed line for a once-
through heat exchange system, if monitoring of the inlet water feed is 
elected as provided in paragraph (g)(2)(ii) of this section.
    (5) A leak is defined as described in paragraph (g)(5)(i) or (ii) 
of this section, as applicable.
    (i) For once-through heat exchange systems for which the inlet 
water feed is monitored as described in paragraph (g)(2)(ii) of this 
section, a leak is detected if the difference in the measurement value 
of the sample taken from a location specified in paragraph (g)(2)(i) of 
this section and the measurement value of the corresponding sample 
taken from the location specified in paragraph (g)(2)(ii) of this 
section equals or exceeds the leak action level.
    (ii) For all other heat exchange systems, a leak is detected if a 
measurement value of the sample taken from a location specified in 
paragraph (g)(1)(i) or (ii) or (g)(2)(i) of this section equals or 
exceeds the leak action level.
    (6) For heat exchange systems in ethylene oxide service, as defined 
in Sec.  63.101, the monitoring frequency is weekly.
    (h) If a leak is detected using the methods described in paragraph 
(g) of this section, owners and operators must repair the leak to 
reduce the concentration or mass emissions rate to below the applicable 
leak action level as soon as practicable, but no later than 45 days 
after identifying the leak, except as specified in paragraph (h)(6) or 
(j) of this section. Repair must include re-monitoring at the 
monitoring location where the leak was identified according to the 
method specified in paragraph (g)(3) of this section to verify that the 
total strippable hydrocarbon concentration or total hydrocarbon mass 
emissions rate is below the applicable leak action level. Repair may 
also include performing the additional monitoring in paragraph (i) of 
this section to verify that the total strippable hydrocarbon 
concentration or total hydrocarbon mass emissions rate is below the 
applicable leak action level. Actions that can be taken to achieve 
repair include but are not limited to:
    (1) Physical modifications to the leaking heat exchanger, such as 
welding the leak or replacing a tube;
    (2) Blocking the leaking tube within the heat exchanger;
    (3) Changing the pressure so that water flows into the process 
fluid;
    (4) Replacing the heat exchanger or heat exchanger bundle; or
    (5) Isolating, bypassing, or otherwise removing the leaking heat 
exchanger from service until it is otherwise repaired.
    (6) For heat exchange systems in ethylene oxide service, as defined 
in Sec.  63.101, paragraph (j) of this section does not apply, and 
owners and operators must repair the leak to reduce the concentration 
or mass emissions rate to below the applicable leak action level as 
soon as practicable, but no later than 15 days after the sample was 
collected. Delay of repair of heat exchange systems in ethylene oxide 
service for which leaks have been detected is allowed if the equipment 
is isolated from the process such that it is no longer in ethylene 
oxide service.
    (i) If an owner or operator detects a leak when monitoring a 
cooling tower return line under paragraph (g)(1)(i) of this section, 
then the owner or operator may conduct additional monitoring of each 
heat exchanger or group of heat exchangers associated with the heat 
exchange system for which the leak was detected, as provided in 
paragraph (g)(1)(ii) of this section. If no leaks are detected when 
monitoring according to the requirements of paragraph (g)(1)(ii) of 
this section, the heat exchange system is considered to have met the 
repair requirements through re-monitoring of the heat exchange system, 
as provided in paragraph (h) of this section.
    (j) Owners and operators may delay repair when one of the 
conditions in paragraph (j)(1) or (2) of this section is met and the 
leak is less than the delay of repair action level specified in 
paragraph (j)(3) of this section. Owners and operators must determine 
if a delay of repair is necessary as soon as

[[Page 43169]]

practicable, but no later than 45 days after first identifying the 
leak.
    (1) If the repair is technically infeasible without a shutdown and 
the total strippable hydrocarbon concentration or total hydrocarbon 
mass emissions rate is initially and remains less than the delay of 
repair action level for all monitoring periods during the delay of 
repair, then the owner or operator may delay repair until the next 
scheduled shutdown of the heat exchange system. If, during subsequent 
monitoring, the delay of repair action level is exceeded, then owners 
and operators must repair the leak within 30 days of the monitoring 
event in which the leak was equal to or exceeded the delay of repair 
action level.
    (2) If the necessary equipment, parts, or personnel are not 
available and the total strippable hydrocarbon concentration or total 
hydrocarbon mass emissions rate is initially and remains less than the 
delay of repair action level for all monitoring periods during the 
delay of repair, then the owner or operator may delay the repair for a 
maximum of 120 calendar days. Owners and operators must demonstrate 
that the necessary equipment, parts, or personnel were not available. 
If, during subsequent monitoring, the delay of repair action level is 
exceeded, then owners and operators must repair the leak within 30 days 
of the monitoring event in which the leak was equal to or exceeded the 
delay of repair action level.
    (3) The delay of repair action level is a total strippable 
hydrocarbon concentration (as methane) in the stripping gas of 62 ppmv 
or, for heat exchange systems with a recirculation rate of 10,000 
gallons per minute or less, the delay of repair action level is a total 
hydrocarbon mass emissions rate (as methane) of 1.8 kg/hr. The delay of 
repair action level is assessed as described in paragraph (j)(3)(i) or 
(ii) of this section, as applicable.
    (i) For once-through heat exchange systems for which the inlet 
water feed is monitored as described in paragraph (g)(2)(ii) of this 
section, the delay of repair action level is exceeded if the difference 
in the measurement value of the sample taken from a location specified 
in paragraph (g)(2)(i) of this section and the measurement value of the 
corresponding sample taken from the location specified in paragraph 
(g)(2)(ii) of this section equals or exceeds the delay of repair action 
level.
    (ii) For all other heat exchange systems, the delay of repair 
action level is exceeded if a measurement value of the sample taken 
from a location specified in paragraph (g)(1)(i), (1)(ii), or (2)(i) of 
this section equals or exceeds the delay of repair action level.
    (k) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(11), owners and 
operators must not inject water into or dispose of water through any 
heat exchange system in a chemical manufacturing process unit meeting 
the conditions of Sec.  63.100(b)(1) through (3) if the water contains 
any amount of ethylene oxide, has been in contact with any process 
stream containing ethylene oxide, or the water is considered wastewater 
as defined in Sec.  63.101.
    (l) If 99 percent by weight or more of the organic compounds that 
could leak into the heat exchange system are water soluble and have a 
Henry's Law Constant less than 5.0E-6 atmospheres-cubic meters/mol at 
25 degrees Celsius, beginning no later than the compliance dates 
specified in Sec.  63.100(k)(10), owners and operators may monitor the 
cooling water for leaks according to the requirements in paragraph (b) 
of this section in lieu of using the Modified El Paso Method. If an 
owner or operator detects a leak according to paragraph (b) of this 
section, then the owner or operator must repair it according to 
paragraph (l)(1) of this section, unless repair is delayed according to 
paragraph (l)(2) of this section.
    (1) If a leak is detected using the methods described in paragraph 
(l) of this section, the owner or operator must repair the leak as soon 
as practicable, but no later than 45 days after identifying the leak, 
except as specified in paragraph (l)(2) of this section. Repair must 
include re-monitoring at the monitoring location where the leak was 
identified to verify that the criteria in paragraph (b)(6) of this 
section is no longer met. Actions that can be taken to achieve repair 
include but are not limited to:
    (i) Physical modifications to the leaking heat exchanger, such as 
welding the leak or replacing a tube;
    (ii) Blocking the leaking tube within the heat exchanger;
    (iii) Changing the pressure so that water flows into the process 
fluid;
    (iv) Replacing the heat exchanger or heat exchanger bundle; or
    (v) Isolating, bypassing, or otherwise removing the leaking heat 
exchanger from service until it is otherwise repaired.
    (2) The owner or operator may delay repair when the conditions in 
paragraph (e) of this section are met.

0
48. Amend Sec.  63.105 by revising paragraphs (d) and (e) to read as 
follows:


Sec.  63.105  Maintenance wastewater requirements.

* * * * *
    (d) The owner or operator shall incorporate the procedures 
described in paragraphs (b) and (c) of this section as part of the 
startup, shutdown, and malfunction plan required under Sec.  
63.6(e)(3). For each source as defined in Sec.  63.101, on and after 
July 15, 2027, this paragraph no longer applies.
    (e) The owner or operator shall maintain a record of the 
information required by paragraphs (b) and (c) of this section as part 
of the start-up, shutdown, and malfunction plan required under Sec.  
63.6(e)(3). For each source as defined in Sec.  63.101, on and after 
July 15, 2027, the phrase ``as part of the start-up, shutdown, and 
malfunction plan required under Sec.  63.6(e)(3)'' in this paragraph no 
longer applies.

0
49. Amend Sec.  63.107 by revising paragraph (i) and adding paragraph 
(j) to read as follows:


Sec.  63.107  Identification of process vents subject to this subpart.

* * * * *
    (i) Except as specified in paragraph (j) of this section, the gas 
stream would meet the characteristics specified in paragraphs (b) 
through (g) of this section, but, for purposes of avoiding 
applicability, has been deliberately interrupted, temporarily 
liquefied, routed through any item of equipment for no process purpose, 
or disposed of in a flare that does not meet the criteria in Sec.  
63.11(b), or an incinerator that does not reduce emissions of organic 
HAP by 98 percent or to a concentration of 20 parts per million by 
volume, whichever is less stringent.
    (j) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), the phrase 
``disposed of in a flare that does not meet the criteria in Sec.  
63.11(b)'' in paragraph (i) of this section is replaced with ``disposed 
of in a flare that does not meet the criteria in Sec.  63.108''.

0
50. Add Sec.  63.108 to read as follows:


Sec.  63.108  Flare requirements.

    (a) For any flare that is used to reduce organic HAP emissions from 
a chemical manufacturing process unit, the owner or operator may elect 
to comply with the requirements in this section in lieu of the 
requirements of Sec.  63.11(b) and the requirements referenced therein. 
The owner or operator may also elect to comply with the requirements in 
this section pursuant to the overlap provisions provided in Sec.  
63.110(j). However, for each source as defined in

[[Page 43170]]

Sec.  63.101 and for each source as defined in Sec.  63.191, beginning 
no later than the compliance dates specified in Sec.  63.100(k)(10), 
the provisions specified in paragraphs (a)(1) through (22) of this 
section no longer apply. Instead, if an owner or operator reduces 
organic HAP emissions from a chemical manufacturing process unit by 
venting emissions through a closed-vent system to a steam-assisted, 
air-assisted, non-assisted, or pressure-assisted multi-point flare, 
then the owner or operator must meet the applicable requirements for 
flares as specified in Sec. Sec.  63.670 and 63.671, including the 
provisions in tables 12 and 13 to subpart CC of this part, except as 
specified in paragraphs (b) through (o) of this section. This 
requirement also applies to any flare using fuel gas from a fuel gas 
system, of which 50 percent or more of the fuel gas is derived from a 
chemical manufacturing process unit, as determined on an annual average 
basis. For purposes of compliance with this paragraph, the following 
terms are defined in Sec.  63.641: Assist air, assist steam, center 
steam, combustion zone, combustion zone gas, flare, flare purge gas, 
flare supplemental gas, flare sweep gas, flare vent gas, lower steam, 
net heating value, perimeter assist air, pilot gas, premix assist air, 
total steam, and upper steam.
    (1) Section 63.107(i) related to criteria in Sec.  63.11(b);
    (2) Section 63.113(a)(1);
    (3) Section 63.114(a)(2);
    (4) Section 63.116(a)(1) through (3);
    (5) Section 63.117(a)(5)(i) through (iii);
    (6) Section 63.118(f)(5);
    (7) The last sentence in Sec.  63.119(e)(1) related to flares;
    (8) Section 63.120(e)(1) through (6);
    (9) Section 63.122(c)(2) and (g)(3);
    (10) Section 63.126(b)(2)(i);
    (11) Section 63.127(a)(2);
    (12) Section 63.128(b)(1) through (3);
    (13) Section 63.129(a)(5)(i) through (iii);
    (14) Section 63.130(a)(2)(i), (c), and (d)(5);
    (15) Section 63.139(c)(3) and (d)(3);
    (16) Section 63.145(j)(1) through (3);
    (17) Section 63.146(b)(7)(i)(A) through (C);
    (18) V63.147(d)(1);
    (19) Section 63.172(d);
    (20) Section 63.180(e)(1) through (3);
    (21) Section 63.181(g)(1)(iii); and
    (22) The phrase ``including periods when a flare pilot light system 
does not have a flame'' in Sec.  63.181(g)(2)(i) of subpart H of this 
part.
    (b) When determining compliance with the pilot flame requirements 
specified in Sec.  63.670(b) and (g), substitute ``pilot flame or flare 
flame'' for each occurrence of ``pilot flame.''
    (c) When determining compliance with the flare tip velocity and 
combustion zone operating limits specified in Sec.  63.670(d) and (e), 
the requirement effectively applies starting with the 15-minute block 
that includes a full 15 minutes of the flaring event. The owner or 
operator is required to demonstrate compliance with the velocity and 
NHVcz requirements starting with the block that contains the fifteenth 
minute of a flaring event. The owner or operator is not required to 
demonstrate compliance for the previous 15-minute block in which the 
event started and contained only a fraction of flow.
    (d) Instead of complying with Sec.  63.670(o)(2)(i), owners and 
operators must develop and implement the flare management plan no later 
than the compliance dates specified in Sec.  63.100(k)(10).
    (e) Instead of complying with Sec.  63.670(o)(2)(iii), if required 
to develop a flare management plan and submit it to the Administrator, 
then owners and operators must also submit all versions of the plan in 
portable document format (PDF) to the EPA following the procedure 
specified in Sec.  63.9(k), except any medium submitted through mail 
must be sent to the attention of the Hazardous Organic Chemical 
Manufacturing Sector Lead.
    (f) Section 63.670(o)(3)(ii) and all references to it do not apply. 
Instead, the owner or operator must comply with the maximum flare tip 
velocity operating limit at all times.
    (g) Substitute ``chemical manufacturing process unit'' for each 
occurrence of ``petroleum refinery.''
    (h) Each occurrence of ``refinery'' does not apply.
    (i) If a pressure-assisted multi-point flare is used as a control 
device, then owners and operators must meet the following conditions:
    (1) The owner or operator is not required to comply with the flare 
tip velocity requirements in Sec.  63.670(d) and (k);
    (2) The NHVcz for pressure-assisted mulit-point flares is 800 Btu/
scf;
    (3) Owners and operators must determine the 15-minute block average 
NHVvg using only the direct calculation method specified in Sec.  
63.670(l)(5)(ii);
    (4) Instead of complying with Sec.  63.670(b) and (g), if a 
pressure-assisted multi-point flare uses cross-lighting on a stage of 
burners rather than having an individual pilot flame on each burner, 
then owners and operators must operate each stage of the pressure-
assisted multi-point flare with a flame present at all times when 
regulated material is routed to that stage of burners. Each stage of 
burners that cross-lights in the pressure-assisted multi-point flare 
must have at least two pilots with at least one continuously lit and 
capable of igniting all regulated material that is routed to that stage 
of burners. Each 15-minute block during which there is at least one 
minute where no pilot flame is present on a stage of burners when 
regulated material is routed to the flare is a violation of the 
standard. Violations in different 15-minute blocks from the same event 
are considered separate violations. The pilot flame(s) on each stage of 
burners that use cross-lighting must be continuously monitored by a 
thermocouple or any other equivalent device used to detect the presence 
of a flame;
    (5) Unless the owner or operator chooses to conduct a cross-light 
performance demonstration as specified in this paragraph, owners and 
operators must ensure that if a stage of burners on the flare uses 
cross-lighting, that the distance between any two burners in series on 
that stage is no more than 6 feet when measured from the center of one 
burner to the next burner. A distance greater than 6 feet between any 
two burners in series may be used provided the owner or operator 
conducts a performance demonstration that confirms the pressure-
assisted multi-point flare will cross-light a minimum of three burners 
and the spacing between the burners and location of the pilot flame 
must be representative of the projected installation. The compliance 
demonstration must be approved by the permitting authority and a copy 
of this approval must be maintained onsite. The compliance 
demonstration report must include: a protocol describing the test 
methodology used, associated test method QA/QC parameters, the waste 
gas composition and NHVcz of the gas tested, the velocity of the waste 
gas tested, the pressure-assisted multi-point flare burner tip 
pressure, the time, length, and duration of the test, records of 
whether a successful cross-light was observed over all of the burners 
and the length of time it took for the burners to cross-light, records 
of maintaining a stable flame after a successful cross-light and the 
duration for which this was observed, records of any smoking events 
during the cross-light, waste gas temperature, meteorological 
conditions (e.g., ambient temperature, barometric pressure, wind speed 
and direction, and relative humidity), and whether there were any 
observed flare flameouts; and
    (6) Owners and operators must install and operate pressure 
monitor(s) on the

[[Page 43171]]

main flare header, as well as a valve position indicator monitoring 
system for each staging valve to ensure that the flare operates within 
the proper range of conditions as specified by the manufacturer. The 
pressure monitor must meet the requirements in table 13 to subpart CC 
of this part.
    (7) If a pressure-assisted multi-point flare is operating under the 
requirements of an approved alternative means of emission limitations, 
owners and operators must either continue to comply with the terms of 
the alternative means of emission limitations or comply with the 
provisions in paragraphs (i)(1) through (6) of this section.
    (j) If an owner or operator chooses to determine compositional 
analysis for net heating value with a continuous process mass 
spectrometer, then the owner or operator must comply with the 
requirements specified in paragraphs (j)(1) through (7) of this 
section.
    (1) Owners and operators must meet the requirements in Sec.  
63.671(e)(2). The owner or operator may augment the minimum list of 
calibration gas components found in Sec.  63.671(e)(2) with compounds 
found during a pre-survey or known to be in the gas through process 
knowledge.
    (2) Calibration gas cylinders must be certified to an accuracy of 2 
percent and traceable to National Institute of Standards and Technology 
(NIST) standards.
    (3) For unknown gas components that have similar analytical mass 
fragments to calibration compounds, the owner or operator may report 
the unknowns as an increase in the overlapped calibration gas compound. 
For unknown compounds that produce mass fragments that do not overlap 
calibration compounds, the owner or operator may use the response 
factor for the nearest molecular weight hydrocarbon in the calibration 
mix to quantify the unknown component's NHVvg.
    (4) The owner or operator may use the response factor for n-pentane 
to quantify any unknown components detected with a higher molecular 
weight than n-pentane.
    (5) Owners and operators must perform an initial calibration to 
identify mass fragment overlap and response factors for the target 
compounds.
    (6) Owners and operators must meet applicable requirements in 
Performance Specification 9 in appendix B to part 60 of this chapter 
for continuous monitoring system acceptance including, but not limited 
to, performing an initial multi-point calibration check at three 
concentrations following the procedure in section 10.1 and performing 
the periodic calibration requirements listed for gas chromatographs in 
table 13 to subpart CC of this part, for the process mass spectrometer. 
The owner or operator may use the alternative sampling line temperature 
allowed under Net Heating Value by Gas Chromatograph in table 13 to 
subpart CC of this part.
    (7) The average instrument calibration error (CE) for each 
calibration compound at any calibration concentration must not differ 
by more than 10 percent from the certified cylinder gas value. The CE 
for each component in the calibration blend must be calculated using 
equation 1 to this paragraph.
Equation 1 to Paragraph (j)(7)
[GRAPHIC] [TIFF OMITTED] TR16MY24.054

Where:

Cm = Average instrument response (ppm)
Ca = Certified cylinder gas value (ppm)

    (k) If an owner or operator use a gas chromatograph or mass 
spectrometer for compositional analysis for net heating value, then the 
owner or operator may choose to use the CE of NHVmeasured 
versus the cylinder tag value NHV as the measure of agreement for daily 
calibration and quarterly audits in lieu of determining the compound-
specific CE. The CE for NHV at any calibration level must not differ by 
more than 10 percent from the certified cylinder gas value. The CE for 
must be calculated using equation 2 to this paragraph.
Equation 2 to Paragraph (k)
[GRAPHIC] [TIFF OMITTED] TR16MY24.055

Where:

NHVmeasured = Average instrument response (Btu/scf)
NHVa = Certified cylinder gas value (Btu/scf)

    (l) Instead of complying with Sec.  63.670(q), owners and operators 
must comply with the reporting requirements specified in paragraphs 
(l)(1) and (2) of this section.
    (1) The initial notification requirements specified in Sec.  
63.152(b)(7).
    (2) The Periodic Report required by Sec.  63.152(c) must include 
the items specified in paragraphs (l)(2)(i) through (vi) of this 
section.
    (i) Records as specified in paragraph (m)(1) of this section for 
each 15-minute block during which there was at least one minute when 
regulated material is routed to a flare and no pilot flame or flare 
flame is present. Include the start and stop time and date of each 15-
minute block.
    (ii) Visible emission records as specified in paragraph (m)(2)(iv) 
of this section for each period of 2 consecutive hours during which 
visible emissions exceeded a total of 5 minutes. Indicate the date and 
start and end times for each period.
    (iii) The periods specified in paragraph (m)(6) of this section. 
Indicate the date and start and end times for each period, and the net 
heating value operating parameter(s) determined following the methods 
in Sec.  63.670(k) through (n) as applicable.
    (iv) For flaring events meeting the criteria in Sec.  63.670(o)(3) 
and paragraph (f) of this section:
    (A) The start and stop time and date of the flaring event.
    (B) The length of time in minutes for which emissions were visible 
from the flare during the event.
    (C) For steam-assisted, air-assisted, and non-assisted flares, the 
start date, start time, and duration in minutes for periods of time 
that the flare tip velocity exceeds the maximum flare tip velocity 
determined using the methods in Sec.  63.670(d)(2) and the maximum 15-
minute block average flare tip velocity in ft/sec recorded during the 
event.
    (D) Results of the root cause and corrective actions analysis 
completed during the reporting period, including the corrective actions 
implemented during the reporting period and, if applicable, the 
implementation

[[Page 43172]]

schedule for planned corrective actions to be implemented subsequent to 
the reporting period.
    (v) For pressure-assisted multi-point flares, the periods of time 
when the pressure monitor(s) on the main flare header show the burners 
operating outside the range of the manufacturer's specifications. 
Indicate the date and start and end times for each period.
    (vi) For pressure-assisted multi-point flares, the periods of time 
when the staging valve position indicator monitoring system indicates a 
stage should not be in operation and is or when a stage should be in 
operation and is not. Indicate the date and start and end times for 
each period.
    (m) Instead of complying with Sec.  63.670(p), owners and operators 
must keep the flare monitoring records specified in paragraphs (m)(1) 
through (14) of this section.
    (1) Retain records of the output of the monitoring device used to 
detect the presence of a pilot flame or flare flame as required in 
Sec.  63.670(b) and the presence of a pilot flame as required in 
paragraph (i)(4) of this section for a minimum of 2 years. Retain 
records of each 15-minute block during which there was at least one 
minute that no pilot flame or flare flame is present when regulated 
material is routed to a flare for a minimum of 5 years. For a pressure-
assisted multi-point flare that uses cross-lighting, retain records of 
each 15-minute block during which there was at least one minute that no 
pilot flame is present on each stage when regulated material is routed 
to a flare for a minimum of 5 years. The owner or operator may reduce 
the collected minute-by-minute data to a 15-minute block basis with an 
indication of whether there was at least one minute where no pilot 
flame or flare flame was present.
    (2) Retain records of daily visible emissions observations as 
specified in paragraphs (m)(2)(i) through (iv) of this section, as 
applicable, for a minimum of 3 years.
    (i) To determine when visible emissions observations are required, 
the record must identify all periods when regulated material is vented 
to the flare.
    (ii) If visible emissions observations are performed using Method 
22 in appendix A-7 to part 60 of this chapter, then the record must 
identify whether the visible emissions observation was performed, the 
results of each observation, total duration in minutes of observed 
visible emissions, and whether it was a 5-minute or 2-hour observation. 
Record the date and start time of each visible emissions observation.
    (iii) If a video surveillance camera is used pursuant to Sec.  
63.670(h)(2), then the record must include all video surveillance 
images recorded, with time and date stamps.
    (iv) For each 2-hour period for which visible emissions are 
observed for more than 5 minutes in 2 consecutive hours, then the 
record must include the date and start and end time of the 2-hour 
period and an estimate of the cumulative number of minutes in the 2-
hour period for which emissions were visible.
    (3) The 15-minute block average cumulative flows for flare vent gas 
and, if applicable, total steam, perimeter assist air, and premix 
assist air specified to be monitored under Sec.  63.670(i), along with 
the date and time interval for the 15-minute block. If multiple 
monitoring locations are used to determine cumulative vent gas flow, 
total steam, perimeter assist air, and premix assist air, then retain 
records of the 15-minute block average flows for each monitoring 
location for a minimum of 2 years and retain the 15-minute block 
average cumulative flows that are used in subsequent calculations for a 
minimum of 5 years. If pressure and temperature monitoring is used, 
then retain records of the 15-minute block average temperature, 
pressure, and molecular weight of the flare vent gas or assist gas 
stream for each measurement location used to determine the 15-minute 
block average cumulative flows for a minimum of 2 years, and retain the 
15-minute block average cumulative flows that are used in subsequent 
calculations for a minimum of 5 years.
    (4) The flare vent gas compositions specified to be monitored under 
Sec.  63.670(j). Retain records of individual component concentrations 
from each compositional analysis for a minimum of 2 years. If an NHVvg 
analyzer is used, retain records of the 15-minute block average values 
for a minimum of 5 years.
    (5) Each 15-minute block average operating parameter calculated 
following the methods specified in Sec.  63.670(k) through (n) as 
applicable.
    (6) All periods during which operating values are outside of the 
applicable operating limits specified in Sec.  63.670(d) through (f) 
and paragraph (i) of this section when regulated material is being 
routed to the flare.
    (7) All periods during which the owner or operator does not perform 
flare monitoring according to the procedures in Sec.  63.670(g) through 
(j).
    (8) For pressure-assisted multi-point flares, if a stage of burners 
on the flare uses cross-lighting, then a record of any changes made to 
the distance between burners.
    (9) For pressure-assisted multi-point flares, all periods when the 
pressure monitor(s) on the main flare header show burners are operating 
outside the range of the manufacturer's specifications. Indicate the 
date and time for each period, the pressure measurement, the stage(s) 
and number of burners affected, and the range of manufacturer's 
specifications.
    (10) For pressure-assisted multi-point flares, all periods when the 
staging valve position indicator monitoring system indicates a stage of 
the pressure-assisted multi-point flare should not be in operation and 
when a stage of the pressure-assisted multi-point flare should be in 
operation and is not. Indicate the date and time for each period, 
whether the stage was supposed to be open, but was closed or vice 
versa, and the stage(s) and number of burners affected.
    (11) Records of periods when there is flow of vent gas to the 
flare, but when there is no flow of regulated material to the flare, 
including the start and stop time and dates of periods of no regulated 
material flow.
    (12) Records when the flow of vent gas exceeds the smokeless 
capacity of the flare, including start and stop time and dates of the 
flaring event.
    (13) Records of the root cause analysis and corrective action 
analysis conducted as required in Sec.  63.670(o)(3) and paragraph (f) 
of this section, including an identification of the affected flare, the 
date and duration of the event, a statement noting whether the event 
resulted from the same root cause(s) identified in a previous analysis 
and either a description of the recommended corrective action(s) or an 
explanation of why corrective action is not necessary under Sec.  
63.670(o)(5)(i).
    (14) For any corrective action analysis for which implementation of 
corrective actions are required in Sec.  63.670(o)(5), a description of 
the corrective action(s) completed within the first 45 days following 
the discharge and, for action(s) not already completed, a schedule for 
implementation, including proposed commencement and completion dates.
    (n) The owner or operator may elect to comply with the alternative 
means of emissions limitation requirements specified in Sec.  63.670(r) 
in lieu of the requirements in Sec.  63.670(d) through (f), as 
applicable. However, instead of complying with Sec.  63.670(r)(3)(iii), 
owners and operators must also submit the alternative means of 
emissions limitation request to the following address: U.S. 
Environmental Protection

[[Page 43173]]

Agency, Office of Air Quality Planning and Standards, Sector Policies 
and Programs Division, U.S. EPA Mailroom (C404-02), Attention: 
Hazardous Organic Chemical Manufacturing Sector Lead, 4930 Old Page 
Rd., Durham, NC 27703.
    (o) The referenced provisions specified in paragraphs (o)(1) 
through (4) of this section do not apply when demonstrating compliance 
with this section.
    (1) Section 63.670(o)(4)(iv) of subpart CC of this part.
    (2) The last sentence of Sec.  63.670(o)(6).
    (3) The phrase ``that were not caused by a force majeure event'' in 
Sec.  63.670(o)(7)(ii).
    (4) The phrase ``that were not caused by a force majeure event'' in 
Sec.  63.670(o)(7)(iv).

0
51. Add Sec.  63.109 to read as follows:


Sec.  63.109  Procedures for determining whether process vents, storage 
vessels, equipment, wastewater, and heat exchange systems are in 
ethylene oxide service.

    This section applies beginning no later than the compliance dates 
specified in Sec.  63.100(k)(11). To determine if process vents, 
storage vessels, equipment leaks, wastewater, and heat exchange systems 
are in ethylene oxide service, as defined in Sec.  63.101, owners and 
operators must comply with the requirements in paragraphs (a) through 
(e) of this section, as applicable.
    (a) Except as specified in paragraph (a)(7) of this section, for 
each Group 1 and Group 2 process vent stream, owners and operators must 
measure the flow rate and concentration of ethylene oxide of each 
process vent as specified in paragraphs (a)(1) through (6) of this 
section.
    (1) Measurements must be made prior to any dilution of the vent 
streams.
    (2) Measurements may be made on the combined vent streams at a 
chemical manufacturing process unit or for each separate vent stream.
    (3) The sampling site shall be after the last recovery device (if 
any recovery devices are present) but prior to the inlet of any control 
device that is present and prior to release to the atmosphere. Method 1 
or 1A of appendix A-1 to part 60 of this chapter, as appropriate, must 
be used for the selection of the sampling sites. For vents smaller than 
0.10 meter in diameter, sample at one point at the center of the duct.
    (4) The gas volumetric flow rate must be determined using Method 2, 
2A, 2C, 2D, 2F, or 2G of appendices A-1 and A-2 to part 60 of this 
chapter (respectively), as appropriate.
    (5) Except as specified in paragraph (a)(6) of this section, the 
concentration of ethylene oxide must be determined using Method 18 of 
appendix A-6 to part 60 of this chapter, or Method 320 of appendix A to 
this part.
    (6) You may elect to use ASTM D6348-12 (Reapproved 2020) 
(incorporated by reference, Sec.  63.14) in lieu of Method 320 of 
appendix A to this part as specified in paragraph (a)(5) of this 
section. To comply with this paragraph, annexes Al through A8 to ASTM 
D6348-12 (Reapproved 2020) are mandatory; the percent (%) R must be 
determined for each target analyte using Equation A5.5 of ASTM D6348-12 
(Reapproved 2020) Annex A5 (Analyte Spiking Technique); and in order 
for the test data to be acceptable for a compound, the %R must be 70% 
>= R <= 130%. If the %R value does not meet this criterion for a target 
compound, then the test data is not acceptable for that compound and 
the test must be repeated for that analyte (i.e., the sampling and/or 
analytical procedure should be adjusted before a retest). The %R value 
for each compound must be reported in the test report, and all field 
measurements must be corrected with the calculated %R value for that 
compound by using the following equation:
Equation 1 to Paragraph (a)(6)
Reported Results = (Measured Concentration in the Stack x 100)/%R.

    (7) The requirements specified in paragraphs (a)(1) through (6) of 
this section for an initial measurement or initial performance test do 
not apply if the conditions specified in paragraphs (a)(7)(i) through 
(iv) of this section are met for a previously conducted measurement or 
performance test.
    (i) No changes have been made to the process since the time of the 
measurement or performance test;
    (ii) The operating conditions and test methods used during 
measurement or performance test conform to the ethylene oxide related 
requirements of this subpart;
    (iii) The control device and process parameter values established 
during the previously conducted measurement or performance test are 
used to demonstrate continuous compliance with the ethylene oxide 
related requirements of this subpart; and
    (iv) The previously conducted measurement or performance test was 
completed within the last 60 months.
    (b) For storage vessels, owners and operators must determine the 
concentration of ethylene oxide of the fluid stored in the storage 
vessels by complying with the requirements in paragraph (b)(1) or (2) 
of this section.
    (1) The owner or operator must measure concentration of ethylene 
oxide of the fluid stored in the storage vessel using Method 624.1 of 
appendix A to 40 CFR part 136, or preparation by Method SW-846-5031 or 
SW-846-5030B and analysis by Method SW-846-8260D (incorporated by 
reference, see Sec.  63.14). The owner or operator may not use a 
preservative in the collected sample; the owner or operator must store 
the sample with minimal headspace as cold as possible and at least 
below 4 degrees C; and the owner or operator must analyze the sample as 
soon as possible, but in no case longer than 7 days from the time the 
sample was collected. If owners and operators collect a sample from a 
pressure vessel, then the owner or operator must maintain the sample 
under pressure both during and following sampling.
    (2) Unless specified by the Administrator, the owner or operator 
may calculate the concentration of ethylene oxide of the fluid stored 
in the storage vessels if information specific to the fluid stored is 
available. Information specific to the fluid stored includes 
concentration data from safety data sheets.
    (c) For equipment leaks, owners and operators must comply with the 
requirements in paragraphs (c)(1) through (4) of this section.
    (1) Each piece of equipment within a chemical manufacturing process 
unit that can reasonably be expected to contain equipment in ethylene 
oxide service is presumed to be in ethylene oxide service unless the 
owner or operator demonstrates that the piece of equipment is not in 
ethylene oxide service. For a piece of equipment to be considered not 
in ethylene oxide service, it must be determined that the percent 
ethylene oxide content of the process fluid that is contained in or 
contacts equipment can be reasonably expected to not exceed 0.1 percent 
by weight on an annual average basis. For purposes of determining the 
percent ethylene oxide content of the process fluid, owners and 
operators must use Method 18 of appendix A-6 to part 60 of this 
chapter, for gaseous process fluid, and Method 624.1 of appendix A to 
part 136 of this chapter, or preparation by Method SW-846-5031 and 
analysis by Method SW-846-8260D (both incorporated by reference, see 
Sec.  63.14) for liquid process fluid. In lieu of preparation by Method 
SW-846-5031, owners and operators may use Method SW-846-5030B 
(incorporated by reference, see Sec.  63.14), as long as: the owner or 
operator does not use a

[[Page 43174]]

preservative in the collected sample; the owner or operator stores the 
sample with minimal headspace as cold as possible and at least below 4 
degrees C; and the owner or operator analyzes the sample as soon as 
possible, but in no case longer than 7 days from the time the sample 
was collected.
    (2) Unless specified by the Administrator, owners and operators may 
use good engineering judgment rather than the procedures specified in 
paragraph (c)(1) of this section to determine that the percent ethylene 
oxide content of the process fluid that is contained in or contacts 
equipment does not exceed 0.1 percent by weight.
    (3) Owners and operators may revise a determination for whether a 
piece of equipment is in ethylene oxide service by following the 
procedures in paragraph (c)(1) of this section, or by documenting that 
a change in the process or raw materials no longer causes the equipment 
to be in ethylene oxide service.
    (4) Samples used in determining the ethylene oxide content must be 
representative of the process fluid that is contained in or contacts 
the equipment.
    (d) For wastewater, owners and operators must determine the 
concentration of ethylene oxide of each wastewater stream using Method 
624.1 of appendix A to part 136 of this chapter, or preparation by 
either Method SW-846-5031 or SW-846-5030B and analysis by Method SW-
846-8260D (incorporated by reference, see Sec.  63.14). The owner or 
operator may not use a preservative in the collected sample; the owner 
or operator must store the sample with minimal headspace as cold as 
possible and at least below 4 degrees C; and the owner or operator must 
analyze the sample as soon as possible, but in no case longer than 7 
days from the time the sample was collected.
    (e) For heat exchange systems, owners and operators must comply 
with the requirements in paragraph (e)(1) or (2) of this section.
    (1) Determine the concentration of ethylene oxide of the process 
fluid cooled by the heat exchange system using Method 624.1 of appendix 
A to part 136 of this chapter, or preparation by either Method SW-846-
5031 or SW-846-5030B and analysis by Method SW-846-8260D (incorporated 
by reference, see Sec.  63.14). The owner or operator may not use a 
preservative in the collected sample; the owner or operator must store 
the sample with minimal headspace as cold as possible and at least 
below 4 degrees C; and the owner or operator must analyze the sample as 
soon as possible, but in no case longer than 7 days from the time the 
sample was collected. soon as possible, but in no case longer than 7 
days from the time the sample was collected.
    (2) Unless specified by the Administrator, owners and operators may 
use good engineering judgment rather than the procedures specified in 
paragraph (e)(1) of this section to determine that the percent ethylene 
oxide content of the process fluid cooled by the heat exchange system 
does not exceed 0.1 percent by weight.

0
52. Amend table 3 to subpart F by:
0
a. Revising entries ``63.6(d)'', ``63.6(e)'', ``63.6(e)(1)(i)'', 
``63.6(e)(1)(ii)'', ``63.6(e)(2)'', ``63.6(e)(3)(i)'', 
``63.6(e)(3)(i)(B)'', ``63.6(e)(3)(i)(C)'', ``63.6(e)(3)(ii)'', 
``63.6(e)(3)(vi)'' and ``63.6(e)(3)(vii)'';
0
b. Removing entries ``63.6(e)(3)(vii)(A)'', ``63.6(e)(3)(vii)(B)'' and 
``63.6(e)(3)(vii)(C)'';
0
c. Revising entries ``63.6(e)(3)(viii)'', ``63.6(e)(3)(ix)'' and 
``63.6(f)(1)'',
0
d. Adding the entry for ``63.7(a)(4)''; and
0
e. Revising entries ``63.7(e)(1)'', ``63.7(f)'', ``63.8(a)(3)'', 
``63.8(a)(4)'', ``63.8(c)(1)(i)'', ``63.8(c)(1)(iii)'', ``63.9(k)'', 
``63.10(d)(5)'' and ``63.11-63.15''.
    The revisions and additions read as follows:

  Table 3 to Subpart F of Part 63--General Provisions Applicability to
                  Subparts F, G, and H \a\ to Subpart F
------------------------------------------------------------------------
                                       Applies to
            Reference              subparts F, G, and       Comment
                                            H
------------------------------------------------------------------------
 
                              * * * * * * *
63.6(d)..........................  [Reserved]........
63.6(e)..........................  Yes \c\...........  Except as
                                                        otherwise
                                                        specified for
                                                        individual
                                                        paragraphs. Does
                                                        not apply to
                                                        Group 2 emission
                                                        points unless
                                                        they are
                                                        included in an
                                                        emissions
                                                        average.\b\ \c\
63.6(e)(1)(i)....................  No................  This is addressed
                                                        by Sec.
                                                        63.102(a)(4) and
                                                        (f) of subpart
                                                        F.
63.6(e)(1)(ii)...................  Yes, before July
                                    15, 2027. No,
                                    beginning on and
                                    after July 15,
                                    2027.
 
                              * * * * * * *
63.6(e)(2).......................  [Reserved]........
63.6(e)(3)(i)....................  Yes, before July    .................
                                    15, 2027. No,
                                    beginning on and
                                    after July 15,
                                    2027.
 
                              * * * * * * *
63.6(e)(3)(i)(B).................  Yes, before July
                                    15, 2027. No,
                                    beginning on and
                                    after July 15,
                                    2027.
63.6(e)(3)(i)(C).................  Yes, before July
                                    15, 2027. No,
                                    beginning on and
                                    after July 15,
                                    2027.
63.6(e)(3)(ii)...................  [Reserved]........
 
                              * * * * * * *
63.6(e)(3)(vi)...................  Yes, before July
                                    15, 2027. No,
                                    beginning on and
                                    after July 15,
                                    2027.
63.6(e)(3)(vii)..................  Yes, before July
                                    15, 2027. No,
                                    beginning on and
                                    after July 15,
                                    2027.
63.6(e)(3)(viii).................  Yes, before July
                                    15, 2027. No,
                                    beginning on and
                                    after July 15,
                                    2027.
63.6(e)(3)(ix)...................  Yes, before July
                                    15, 2027. No,
                                    beginning on and
                                    after July 15,
                                    2027.

[[Page 43175]]

 
63.6(f)(1).......................  No................  Sec.   63.102(a)
                                                        and (e) of
                                                        subpart F
                                                        specifies when
                                                        the standards
                                                        apply.
 
                              * * * * * * *
63.7(a)(4).......................  Yes...............
 
                              * * * * * * *
63.7(e)(1).......................  Yes, before July    See Sec.
                                    15, 2027. No,       63.103(b)(3).
                                    beginning on and
                                    after July 15,
                                    2027.
 
                              * * * * * * *
63.7(f)..........................  Yes...............
 
                              * * * * * * *
63.8(a)(3).......................  [Reserved]........
63.8(a)(4).......................  Yes, except for
                                    flares subject to
                                    Sec.   63.108.
 
                              * * * * * * *
63.8(c)(1)(i)....................  Yes, before July
                                    15, 2027. No,
                                    beginning on and
                                    after July 15,
                                    2027.
 
                              * * * * * * *
63.8(c)(1)(iii)..................  Yes, before July
                                    15, 2027. No,
                                    beginning on and
                                    after July 15,
                                    2027.
 
                              * * * * * * *
63.9(k)..........................  Yes...............
 
                              * * * * * * *
63.10(d)(5)......................  Yes, before July    Except that,
                                    15, 2027. No,       before July 15,
                                    beginning on and    2027, reports
                                    after July 15,      required by Sec.
                                    2027.                 63.10(d)(5)
                                                        shall be
                                                        submitted at the
                                                        time specified
                                                        in Sec.
                                                        63.152(d) of
                                                        subpart G and in
                                                        Sec.   63.182(d)
                                                        of subpart H.
 
                              * * * * * * *
63.11-63.15......................  Yes, except
                                    63.11(b) does not
                                    apply to flares
                                    subject to Sec.
                                    63.108.
------------------------------------------------------------------------
\a\ Wherever subpart A specifies ``postmark'' dates, submittals may be
  sent by methods other than the U.S. Mail (e.g., by fax or courier).
  Submittals shall be sent by the specified dates, but a postmark is not
  necessarily required.
\b\ Except as specified in footnote c of this table, the plan, and any
  records or reports of start-up, shutdown, and malfunction do not apply
  to Group 2 emission points unless they are included in an emissions
  average.
\c\ On and after July 15, 2027, footnote b of this table does not apply
  and the row for the ``63.6(e)'' entry of this table is no longer
  applicable.

Table 4 to Subpart F of Part 63 [Amended]

0
53. Amend table 4 to subpart F by removing the entry for ``Ethylene 
glycol monobutyl ether''.

0
54. Revise the heading to subpart G to read as follows:

Subpart G--National Emission Standards for Hazardous Air Pollutants 
From the Synthetic Organic Chemical Manufacturing Industry for 
Process Vents, Storage Vessels, Transfer Operations, and Wastewater

0
55. Amend Sec.  63.110 by:
0
a. Revising paragraphs (b)(3) and (c)(2)(i);
0
b. Revising paragraphs (d)(2) introductory text, (d)(3), (d)(5) 
introductory text, (d)(6), (d)(8) introductory text, and (d)(9);
0
c. Revising paragraphs (e)(1) introductory text, (f)(2) introductory 
text, (f)(3), (f)(4) introductory text and (h);
0
d. Revising paragraphs (i) introductory text, and (i)(1)(iv); and
0
e. Adding paragraph (j).
    The revisions and addition read as follows:


Sec.  63.110  Applicability.

* * * * *
    (b) * * *
    (3) Except as specified in paragraph (j) of this section, after the 
compliance dates specified in Sec.  63.100, a Group 2 storage vessel 
that is also subject to the provisions of 40 CFR part 61, subpart Y is 
required to comply only with the provisions of part 61, subpart Y, of 
this chapter. The recordkeeping and reporting requirements of part 61, 
subpart Y, will be accepted as compliance with the recordkeeping and 
reporting requirements of this subpart.
    (c) * * *
    (2) * * *
    (i) Except as provided in paragraph (j) of this section, if the 
transfer rack is subject to the control requirements specified in Sec.  
61.302 of this chapter, then the transfer rack is required to comply 
with the control requirements of Sec.  61.302. The owner or operator 
may elect to comply with either the associated testing, monitoring, 
reporting, and recordkeeping requirements of part 61, subpart BB, of 
this chapter or with the testing, monitoring, recordkeeping, and 
reporting requirements specified in this subpart for Group 1 transfer 
racks. The owner or operator shall indicate this decision in either the 
Notification of Compliance Status specified in Sec.  63.152(b) or in an 
operating permit application or amendment.
* * * * *
    (d) * * *
    (2) After the compliance dates specified in Sec.  63.100, the owner 
or

[[Page 43176]]

operator of a Group 2 process vent that is also subject to the 
provisions of part 60, subpart III, of this chapter shall determine 
requirements according to paragraphs (d)(2)(i) and (ii) of this 
section. For each source as defined in Sec.  63.101, on and after July 
15, 2027, this paragraph no longer applies.
* * * * *
    (3) After the compliance dates specified in 63.100, if an owner or 
operator of a process vent subject to this subpart that is also subject 
to the provisions of part 60, subpart III, of this chapter elects to 
control the process vent to the levels required in Sec.  63.113(a)(1) 
or (2) without calculating the TRE index value for the vent according 
to the procedures specified in Sec.  63.115(d), then the owner or 
operator shall comply with the testing, monitoring, reporting, and 
recordkeeping provisions of this subpart and shall be exempt from the 
testing, monitoring, reporting, and recordkeeping provisions of part 
60, subpart III. For each source as defined in Sec.  63.101, on and 
after July 15, 2027, this paragraph no longer applies.
* * * * *
    (5) After the compliance dates specified in Sec.  63.100, the owner 
or operator of a Group 2 process vent that is also subject to the 
provisions of 40 CFR part 60, subpart NNN shall determine requirements 
according to paragraphs (d)(5)(i) and (ii) of this section. For each 
source as defined in Sec.  63.101, on and after July 15, 2027, this 
paragraph no longer applies.
* * * * *
    (6) After the compliance dates specified in Sec.  63.100, if an 
owner or operator of a process vent subject to this subpart that is 
also subject to the provisions of part 60, subpart NNN, of this chapter 
elects to control the process vent to the levels required in Sec.  
63.113(a)(1) or (2) without calculating the TRE index value for the 
vent according to the procedures specified in Sec.  63.115(d), then the 
owner or operator shall comply with the testing, monitoring, reporting, 
and recordkeeping provisions of this subpart and shall be exempt from 
the testing, monitoring, reporting, and recordkeeping provisions of 
part 60, subpart NNN. For each source as defined in Sec.  63.101, on 
and after July 15, 2027, this paragraph no longer applies.
* * * * *
    (8) After the compliance dates specified in Sec.  63.100, the owner 
or operator of a Group 2 process vent that is also subject to the 
provisions of part 60, subpart RRR, of this chapter shall determine 
requirements according to paragraphs (d)(8)(i) and (ii) of this 
section. For each source as defined in Sec.  63.101, on and after July 
15, 2027, this paragraph no longer applies.
* * * * *
    (9) After the compliance dates specified in Sec.  63.100, if an 
owner or operator of a process vent subject to this subpart that is 
also subject to the provisions of part 60, subpart RRR, of this chapter 
elects to control the process vent to the levels required in Sec.  
63.113(a)(1) or (2) without calculating the TRE index value for the 
vent according to the procedures specified in Sec.  63.115(d), then the 
owner or operator shall comply with the testing, monitoring, reporting, 
and recordkeeping provisions of this subpart and shall be exempt from 
the testing, monitoring, reporting, and recordkeeping provisions of 
part 60, subpart RRR. For each source as defined in Sec.  63.101, on 
and after July 15, 2027, this paragraph no longer applies.
* * * * *
    (e) * * *
    (1) Except as specified in paragraph (j) of this section, after the 
compliance dates specified in Sec.  63.100, the owner or operator of a 
Group 1 or Group 2 wastewater stream that is also subject to the 
provisions of part 61, subpart FF, of this chapter is required to 
comply with the provisions of both this subpart and part 61, subpart 
FF. Alternatively, the owner or operator may elect to comply with the 
provisions of paragraphs (e)(1)(i) and (ii) of this section, which 
shall constitute compliance with the provisions of part 61, subpart FF.
* * * * *
    (f) * * *
    (2) Except as specified in paragraph (j) of this section, after the 
compliance dates specified in Sec.  63.100, the owner or operator of 
any Group 2 process vent that is also subject to the provisions of part 
61, subpart F, of this chapter shall comply with the provisions 
specified in either paragraph (f)(2)(i) or (ii) of this section.
* * * * *
    (3) After the compliance dates specified in Sec.  63.100, if an 
owner or operator of a process vent subject to this subpart that is 
also subject to the provisions of part 61, subpart F, of this chapter 
elects to control the process vent to the levels required in Sec.  
63.113(a)(1) or (2) without calculating the TRE index value for the 
vent according to the procedures specified in Sec.  63.115(d), then the 
owner or operator shall comply with the testing, monitoring, reporting, 
and recordkeeping provisions of this subpart and shall be exempt from 
the testing, monitoring, reporting, and recordkeeping provisions of 
part 61, subpart F. For each source as defined in Sec.  63.101, on and 
after July 15, 2027, this paragraph no longer applies.
    (4) Except as specified in paragraph (j) of this section, after the 
compliance dates specified in Sec.  63.100, the owner or operator of a 
Group 1 or Group 2 wastewater stream that is also subject to the 
provisions of 40 CFR part 61, subpart F shall comply with the 
provisions of either paragraph (f)(4)(i) or (ii) of this section.
* * * * *
    (h) Overlap with other regulations for monitoring, recordkeeping, 
or reporting with respect to combustion devices, recovery devices, or 
recapture devices. (1) Except as specified in paragraph (h)(2) of this 
section, after the compliance dates specified in Sec.  63.100, if any 
combustion device, recovery device, or recapture device subject to this 
subpart is also subject to monitoring, recordkeeping, and reporting 
requirements in part 264, subpart AA or CC, of this chapter or is 
subject to monitoring and recordkeeping requirements in part 265, 
subpart AA or CC, of this chapter and the owner or operator complies 
with the periodic reporting requirements under 40 CFR part 264, subpart 
AA or CC that would apply to the device if the facility had final-
permitted status, the owner or operator may elect to comply either with 
the monitoring, recordkeeping, and reporting requirements of this 
subpart, or with the monitoring, recordkeeping, and reporting 
requirements in parts 264 and/or 265, as described in this paragraph, 
which shall constitute compliance with the monitoring, recordkeeping, 
and reporting requirements of this subpart. The owner or operator shall 
identify which option has been selected in the Notification of 
Compliance Status required by Sec.  63.152(b).
    (2) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10) of subpart F 
of this part, paragraph (h)(1) of this section no longer applies.
    (i) Alternative means of compliance-- For each source as defined in 
Sec.  63.101, on and after July 15, 2027, this paragraph (i) no longer 
applies.
    (1) * * *
    (iv) For equipment, comply with Sec.  63.160(g).
* * * * *
    (j) Overlap with other regulations for flares. (1) For each source 
as defined in Sec.  63.101, beginning no later than the compliance 
dates specified in

[[Page 43177]]

Sec.  63.100(k)(10), flares used as a control device to comply with the 
overlap provisions in either paragraph (b)(3), (c)(2)(i), (e)(1), 
(f)(2)(i), (f)(2)(ii), or (f)(4)(i) or (ii) of this section must comply 
with the provisions specified in Sec.  63.108 and are no longer subject 
to any flare related provisions of part 61, subparts F, Y, BB, and FF, 
of this chapter or Sec.  60.18 of this chapter.
    (2) Owners and operators of flares that are subject to the flare 
related requirements of this subpart and flare related requirements of 
any other regulation in part 60, 61, or 63 of this chapter, may elect 
to comply with the requirements in Sec.  63.108 in lieu of all flare 
related requirements in any other regulation in part 60, 61, or 63.

0
56. Revise Sec.  63.111 to read as follows:


Sec.  63.111  Definitions.

    All terms used in this subpart shall have the meaning given them in 
the Act and in subpart F of this part.

0
57. Revise and republish Sec.  63.113 to read as follows:


Sec.  63.113  Process vent provisions--reference control technology.

    (a) The owner or operator of a Group 1 process vent as defined in 
this subpart shall comply with the requirements of paragraph (a)(1), 
(2), (3), or (4) of this section, and paragraph (a)(5) of this section. 
The owner or operator who transfers a gas stream that has the 
characteristics specified in Sec.  63.107(b) through (h) or meets the 
criteria specified in Sec.  63.107(i) to an off-site location or an on-
site location not owned or operated by the owner or operator of the 
source for disposal shall comply with the requirements of paragraph (i) 
of this section.
    (1) Reduce emissions of organic HAP using a flare.
    (i) Except as specified in Sec.  63.108(a), the flare shall comply 
with the requirements of Sec.  63.11(b).
    (ii) Halogenated vent streams, as defined in Sec.  63.111, shall 
not be vented to a flare.
    (2) Reduce emissions of total organic hazardous air pollutants by 
98 weight-percent or to a concentration of 20 parts per million by 
volume. For combustion devices, the emission reduction or concentration 
shall be calculated on a dry basis, corrected to 3-percent oxygen, and 
compliance can be determined by measuring either organic hazardous air 
pollutants or total organic carbon using the procedures in Sec.  
63.116.
    (i) Compliance with paragraph (a)(2) of this section may be 
achieved by using any combination of combustion, recovery, and/or 
recapture devices, except that a recovery device may not be used to 
comply with paragraph (a)(2) of this section by reducing emissions of 
total organic hazardous air pollutants by 98 weight-percent, except as 
provided in paragraph (a)(2)(ii) of this section.
    (ii) An owner or operator may use a recovery device, alone or in 
combination with one or more combustion or recapture devices, to reduce 
emissions of total organic hazardous air pollutants by 98 weight-
percent if all the conditions of paragraphs (a)(2)(ii)(A) through 
(a)(2)(ii)(D) of this section are met.
    (A) The recovery device (and any combustion device or recapture 
device which operates in combination with the recovery device to reduce 
emissions of total organic hazardous air pollutants by 98 weight-
percent) was installed before the date of proposal of the subpart of 
this part 63 that makes this subpart G applicable to process vents in 
the chemical manufacturing process unit.
    (B) The recovery device that will be used to reduce emissions of 
total organic hazardous air pollutants by 98 weight-percent is the last 
recovery device before emission to the atmosphere.
    (C) The recovery device, alone or in combination with one or more 
combustion or recapture devices, is capable of reducing emissions of 
total organic hazardous air pollutants by 98 weight-percent, but is not 
capable of reliably reducing emissions of total organic hazardous air 
pollutants to a concentration of 20 parts per million by volume.
    (D) If the owner or operator disposed of the recovered material, 
the recovery device would comply with the requirements of this subpart 
for recapture devices.
    (3) Except as specified in paragraph (a)(4) of this section, 
achieve and maintain a TRE index value greater than 1.0 at the outlet 
of the final recovery device, or prior to release of the vent stream to 
the atmosphere if no recovery device is present. If the TRE index value 
is greater than 1.0, the process vent shall comply with the provisions 
for a Group 2 process vent specified in either paragraph (d) or (e) of 
this section, whichever is applicable.
    (4) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), the 
provisions specified in paragraphs (a)(4)(i) through (xv) of this 
section no longer apply. Instead, an owner or operator of a Group 1 
process vent as defined in Sec.  63.101 must comply with the 
requirements of paragraph (a)(1) or (2) of this section; and an owner 
or operator of a Group 2 process vent as defined in Sec.  63.101 must 
comply with the requirements of paragraph (f) or (g) of this section.
    (i) Paragraphs (a)(3), (d), and (e) of this section;
    (ii) Section 63.114(b) and (c)(2);
    (iii) Section 63.115(d), except (d)(2)(v);
    (iv) The following phrases in Sec.  63.115(e): ``TRE index value'', 
``changes that are within the range on which the original TRE 
calculation was based'', and ``the recalculated TRE index value is less 
than or equal to 1.0, or less than or equal to 4.0 but greater than 
1.0'';
    (v) The following phrases in Sec.  63.115(f): ``TRE index value'', 
and ``regardless of the TRE index value determined at the location 
specified in Sec.  63.115(a)'';
    (vi) The last two sentences in Sec.  63.115(f)(2): ``If the 
combined vent stream is a Group 2 process vent as determined by the 
previous sentence, but one or more of the HON streams, or combinations 
of HON streams, has a TRE index value greater than 1 but less than or 
equal to 4, the combined vent stream is a process vent with a TRE index 
value greater than 1 but less than or equal to 4. In this case, the 
owner or operator shall monitor the combined vent stream as required by 
Sec.  63.114(b).'';
    (vii) The phrase in Sec.  63.117(a): ``or the provisions for Group 
2 process vents with a TRE index value greater than 1.0 but less than 
or equal to 4.0 in Sec.  63.113(d)'';
    (viii) The phrase in Sec.  63.117(a)(3): ``TRE determinations or'';
    (ix) Section 63.117(a)(7) and (b);
    (x) Section 63.118(b), (c), (d)(3), (e)(3), (h), (i), (j), and 
(k)(4);
    (xi) The following phrase in Sec.  63.118(g)(2): ``and TRE index 
value'';
    (xii) The last sentence in Sec.  63.150(g)(2)(iii)(B)(2);
    (xiii) The phrase in Sec.  63.150(m)(2)(i): ``and TRE index 
value'';
    (xiv) The last sentence in Sec.  63.151(d)(6)(i); and
    (xv) Table 4 to subpart G of this part.
    (5) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), an owner or 
operator of a Group 1 process vent as defined in Sec.  63.101 that 
contains chlorine, hydrogen chloride, or any other chlorinated compound 
must reduce emissions of dioxins and furans (toxic equivalency basis) 
to a concentration of 0.054 nanograms per standard cubic meter on a dry 
basis corrected to 3 percent oxygen.
    (b) If a boiler or process heater is used to comply with the 
percent reduction requirement or concentration limit specified in 
paragraph (a)(2) of this

[[Page 43178]]

section, then the vent stream shall be introduced into the flame zone 
of such a device.
    (c) Halogenated vent streams from Group 1 process vents that are 
combusted shall be controlled according to paragraph (c)(1) or (2) of 
this section.
    (1) If a combustion device is used to comply with paragraph (a)(2) 
of this section for a halogenated vent stream, then the gas stream 
exiting the combustion device shall be conveyed to a halogen reduction 
device, such as a scrubber, before it is discharged to the atmosphere.
    (i) Except as provided in paragraph (c)(1)(ii) of this section, the 
halogen reduction device shall reduce overall emissions of hydrogen 
halides and halogens, as defined in Sec.  63.111 of this subpart, by 99 
percent or shall reduce the outlet mass of total hydrogen halides and 
halogens to less than 0.45 kilogram per hour.
    (ii) If a scrubber or other halogen reduction device was installed 
prior to December 31, 1992, the device shall reduce overall emissions 
of hydrogen halides and halogens, as defined in Sec.  63.111, by 95 
percent or shall reduce the outlet mass of total hydrogen halides and 
halogens to less than 0.45 kilograms per hour.
    (2) A halogen reduction device, such as a scrubber or other 
technique, may be used to reduce the vent stream halogen atom mass 
emission rate to less than 0.45 kilogram per hour prior to any 
combustion control device, and thus make the vent stream 
nonhalogenated; the vent stream must comply with the requirements of 
paragraph (a)(1) or (2) of this section.
    (d) Except as specified in paragraph (a)(4) of this section, the 
owner or operator of a Group 2 process vent having a flow rate greater 
than or equal to 0.005 standard cubic meter per minute, a HAP 
concentration greater than or equal to 50 parts per million by volume, 
and a TRE index value greater than 1.0 but less than or equal to 4.0 
shall maintain a TRE index value greater than 1.0 and shall comply with 
the monitoring of recovery device parameters in Sec.  63.114(b) or (c), 
the TRE index calculations of Sec.  63.115 of this subpart, and the 
applicable reporting and recordkeeping provisions of Sec. Sec.  63.117 
and 63.118. Such owner or operator is not subject to any other 
provisions of Sec. Sec.  63.114 through 63.118.
    (e) Except as specified in paragraph (a)(4) of this section, the 
owner or operator of a Group 2 process vent with a TRE index value 
greater than 4.0 shall maintain a TRE index value greater than 4.0, 
comply with the provisions for calculation of a TRE index value in 
Sec.  63.115 and the reporting and recordkeeping provisions in 
Sec. Sec.  63.117(b) and 63.118(c) and (h), and is not subject to 
monitoring or any other provisions of Sec. Sec.  63.114 through 63.118.
    (f) Except as specified in paragraph (l) of this section, the owner 
or operator of a Group 2 process vent with a flow rate less than 0.005 
standard cubic meter per minute shall maintain a flow rate less than 
0.005 standard cubic meter per minute; comply with the Group 
determination procedures in Sec.  63.115 (a), (b), and (e); and the 
reporting and recordkeeping requirements in Sec. Sec.  63.117(c), 
63.118(d), and 63.118(i); and is not subject to monitoring or any other 
provisions of Sec. Sec.  63.114 through 63.118.
    (g) Except as specified in paragraph (l) of this section, the owner 
or operator of a Group 2 process vent with a total organic HAP 
concentration less than 50 parts per million by volume shall maintain a 
total organic HAP concentration less than 50 parts per million by 
volume; comply with the Group determination procedures in Sec.  
63.115(a), (c), and (e); the reporting and recordkeeping requirements 
in Sec. Sec.  63.117(d) and 63.118(e) and (j); and is not subject to 
monitoring or any other provisions of Sec. Sec.  63.114 through 63.118.
    (h) The owner or operator of a process vent complying with 
paragraph (a)(1) or (2) of this section is not required to perform the 
group determination described in Sec.  63.115.
    (i) Off-site control or on-site control not owned or operated by 
the source. This paragraph (i) applies to gas streams that have the 
characteristics specified in Sec.  63.107(b) through (h) or meet the 
criteria specified in Sec.  63.107(i); that are transferred for 
disposal to an on-site control device (or other compliance equipment) 
not owned or operated by the owner or operator of the source generating 
the gas stream, or to an off-site control device or other compliance 
equipment; and that have the characteristics (e.g., flow rate, total 
organic HAP concentration, or TRE index value as applicable) of a Group 
1 process vent, determined at the point of transfer.
    (i) Comply with the provisions specified in Sec.  63.114(d) for 
each gas stream prior to transfer.
    (ii) Notify the transferee that the gas stream contains organic 
hazardous air pollutants that are to be treated in accordance with the 
provisions of this subpart. The notice shall be submitted to the 
transferee initially and whenever there is a change in the required 
control.
    (2) The owner or operator may not transfer the gas stream unless 
the transferee has submitted to the EPA a written certification that 
the transferee will manage and treat any gas stream transferred under 
this paragraph (i) and received from a source subject to the 
requirements of this subpart in accordance with the requirements of 
either Sec. Sec.  63.113 through 63.118, or Sec.  63.102(b), or subpart 
D of this part if alternative emission limitations have been granted 
the transferor in accordance with those provisions. The certifying 
entity may revoke the written certification by sending a written 
statement to EPA and the owner or operator giving at least 90 days 
notice that the certifying entity is rescinding acceptance of 
responsibility for compliance with the regulatory provisions listed in 
this paragraph (i). Upon expiration of the notice period, the owner or 
operator may not transfer the gas stream to the transferee. Records 
retained by the transferee shall be retained in accordance with Sec.  
63.103(c).
    (3) By providing this written certification to EPA, the certifying 
entity accepts responsibility for compliance with the regulatory 
provisions listed in paragraph (i)(2) of this section with respect to 
any transfer covered by the written certification. Failure to abide by 
any of those provisions with respect to such transfers may result in 
enforcement action by EPA against the certifying entity in accordance 
with the enforcement provisions applicable to violations of these 
provisions by owners or operators of sources.
    (4) Written certifications and revocation statements to EPA from 
the transferees of such gas streams shall be signed by a responsible 
official of the certifying entity, provide the name and address of the 
certifying entity, and be sent to the appropriate EPA Regional Office 
at the addresses listed in Sec.  63.13. Such written certifications are 
not transferable by the transferee.
    (j) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(11), if the 
Group 1 or Group 2 process vent contains ethylene oxide such that it is 
considered to be in ethylene oxide service, as defined in Sec.  63.101, 
then the owner or operator must comply with the requirements of 
paragraphs (j)(1) or (2) of this section in addition to all other 
applicable requirements specified elsewhere in this section.
    (1) Reduce emissions of ethylene oxide by venting emissions through 
a closed vent system to a flare; or
    (2) Reduce emissions of ethylene oxide by venting emissions through 
a closed vent system to a control device that reduces ethylene oxide by 
greater than or equal to 99.9 percent by weight,

[[Page 43179]]

or to a concentration less than 1 ppmv for each process vent or to less 
than 5 pounds per year for all combined process vents within the 
process. If a combustion device is used, the ethylene oxide 
concentration of 1 ppmv must be corrected to 3 percent oxygen.
    (k) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), an owner or 
operator may designate a process vent as a maintenance vent if the vent 
is only used as a result of startup, shutdown, maintenance, or 
inspection of equipment where equipment is emptied, depressurized, 
degassed, or placed into service. The owner or operator must comply 
with the applicable requirements in paragraphs (k)(1) through (4) of 
this section for each maintenance vent. Any vent designated as a 
maintenance vent is only subject to the maintenance vent provisions in 
this paragraph (k) and the associated reporting and recordkeeping 
requirements in Sec.  63.118(f)(9) and (m), respectively. The owner or 
operator does not need to designate a maintenance vent as a Group 1 or 
Group 2 process vent nor identify maintenance vents in a Notification 
of Compliance Status report.
    (1) Prior to venting to the atmosphere, remove process liquids from 
the equipment as much as practical and depressurize the equipment to 
either: A flare meeting the requirements of Sec.  63.108, as 
applicable, or using any combination of a non-flare combustion, 
recovery, and/or recapture device meeting the requirements in paragraph 
(a)(2) of this section until one of the following conditions, as 
applicable, is met.
    (i) The concentration of the vapor in the equipment served by the 
maintenance vent is less than 10 percent of its lower explosive limit 
(LEL) and has an outlet concentration less than or equal to 20 ppmv 
hydrogen halide and halogen HAP.
    (ii) If there is no ability to measure the concentration of the 
vapor in the equipment based on the design of the equipment, the 
pressure in the equipment served by the maintenance vent is reduced to 
5 pounds per square inch gauge (psig) or less. Upon opening the 
maintenance vent, active purging of the equipment cannot be used until 
the concentration of the vapors in the maintenance vent (or inside the 
equipment if the maintenance is a hatch or similar type of opening) is 
less than 10 percent of its LEL.
    (iii) The equipment served by the maintenance vent contains less 
than 50 pounds of total volatile organic compounds (VOC).
    (iv) If, after applying best practices to isolate and purge 
equipment served by a maintenance vent, none of the applicable 
criterion in paragraphs (k)(1)(i) through (iii) of this section can be 
met prior to installing or removing a blind flange or similar equipment 
blind, then the pressure in the equipment served by the maintenance 
vent must be reduced to 2 psig or less before installing or removing 
the equipment blind. During installation or removal of the equipment 
blind, active purging of the equipment may be used provided the 
equipment pressure at the location where purge gas is introduced 
remains at 2 psig or less.
    (2) Except for maintenance vents complying with the alternative in 
paragraph (k)(1)(iii) of this section, the owner or operator must 
determine the concentration or, if applicable, equipment pressure using 
process instrumentation or portable measurement devices and follow 
procedures for calibration and maintenance according to manufacturer's 
specifications.
    (3) For maintenance vents complying with the alternative in 
paragraph (k)(1)(iii) of this section, the owner or operator must 
determine mass of VOC in the equipment served by the maintenance vent 
based on the equipment size and contents after considering any contents 
drained or purged from the equipment. Equipment size may be determined 
from equipment design specifications. Equipment contents may be 
determined using process knowledge.
    (4) In addition to complying with the requirements in paragraphs 
(k)(1) through (3) of this section, for process vents in ethylene oxide 
service, subject to the requirements of Sec.  63.124 that are 
designated as maintenance vents, owners and operators may not release 
more than 1.0 tons of ethylene oxide from all maintenance vents 
combined per any consecutive 12-month period. The owner or operator 
must keep monthly records of the quantity in tons of ethylene oxide 
released from each maintenance vent and include a description of the 
method used to estimate this quantity.
    (l) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraphs 
(f) and (g) of this section no longer apply. Instead, the owner or 
operator of a Group 2 process vent with a total organic HAP mass flow 
rate less than 1.0 pound per hour shall maintain a total organic HAP 
mass flow rate less than 1.0 pound per hour; comply with the Group 
determination procedures in Sec.  63.115(g); and the reporting and 
recordkeeping requirements in Sec. Sec.  63.117(g) and 63.118(n); and 
is not subject to monitoring or any other provisions of Sec. Sec.  
63.114 through 63.118.

0
58. Revise and republish Sec.  63.114 to read as follows:


Sec.  63.114  Process vent provisions--monitoring requirements.

    (a) Each owner or operator of a process vent that uses a combustion 
device to comply with the requirements in Sec.  63.113(a)(1), (2), or 
(5), or that uses a recovery device or recapture device to comply with 
the requirements in Sec.  63.113(a)(2), shall install monitoring 
equipment specified in paragraph (a)(1), (2), (3), (4), (5), or (6) of 
this section, depending on the type of device used. All monitoring 
equipment shall be installed, calibrated, maintained, and operated 
according to manufacturer's specifications or other written procedures 
that provide adequate assurance that the equipment would reasonably be 
expected to monitor accurately.
    (1) Where an incinerator is used, a temperature monitoring device 
equipped with a continuous recorder is required.
    (i) Where an incinerator other than a catalytic incinerator is 
used, a temperature monitoring device shall be installed in the firebox 
or in the ductwork immediately downstream of the firebox in a position 
before any substantial heat exchange occurs.
    (ii) Where a catalytic incinerator is used, temperature monitoring 
devices shall be installed in the gas stream immediately before and 
after the catalyst bed.
    (2) Where a flare is used, except as specified in Sec.  63.108(a), 
the following monitoring equipment is required: A device (including but 
not limited to a thermocouple, ultra-violet beam sensor, or infrared 
sensor) capable of continuously detecting the presence of a pilot 
flame.
    (3) Where a boiler or process heater of less than 44 megawatts 
design heat input capacity is used, the following monitoring equipment 
is required: a temperature monitoring device in the firebox equipped 
with a continuous recorder. This requirement does not apply to gas 
streams that are introduced with primary fuel or are used as the 
primary fuel.
    (4) Where a scrubber is used with an incinerator, boiler, or 
process heater in the case of halogenated vent streams, the following 
monitoring equipment is required for the scrubber.

[[Page 43180]]

    (i) A pH monitoring device equipped with a continuous recorder 
shall be installed to monitor the pH of the scrubber effluent.
    (ii) A flow meter equipped with a continuous recorder shall be 
located at the scrubber influent for liquid flow. Gas flow rate shall 
be determined using one of the procedures specified in paragraphs 
(a)(4)(ii)(A) through (C) of this section.
    (A) The owner or operator may determine gas flow rate using the 
design blower capacity, with appropriate adjustments for pressure drop.
    (B) If the scrubber is subject to rules in 40 CFR parts 264 through 
266 that have required a determination of the liquid to gas (L/G) ratio 
prior to the applicable compliance date for this subpart specified in 
Sec.  63.100(k), the owner or operator may determine gas flow rate by 
the method that had been utilized to comply with those rules. A 
determination that was conducted prior to the compliance date for this 
subpart may be utilized to comply with this subpart if it is still 
representative.
    (C) The owner or operator may prepare and implement a gas flow rate 
determination plan that documents an appropriate method which will be 
used to determine the gas flow rate. The plan shall require 
determination of gas flow rate by a method which will at least provide 
a value for either a representative or the highest gas flow rate 
anticipated in the scrubber during representative operating conditions 
other than startups, shutdowns, or malfunctions. The plan shall include 
a description of the methodology to be followed and an explanation of 
how the selected methodology will reliably determine the gas flow rate, 
and a description of the records that will be maintained to document 
the determination of gas flow rate. The owner or operator shall 
maintain the plan as specified in Sec.  63.103(c). For each source as 
defined in Sec.  63.101, on and after July 15, 2027, the phrase ``other 
than startups, shutdowns, or malfunctions'' in this paragraph no longer 
applies.
    (5) Where a recovery device or recapture device is used to comply 
with the requirements of Sec.  63.113(a)(2) or (5), the owner or 
operator shall utilize the appropriate monitoring device identified in 
paragraph (a)(5)(i), (ii), (iii), (iv), or (v) of this section. All 
monitoring equipment shall be installed, calibrated, and maintained 
according to the manufacturer's specifications or other written 
procedures that provide adequate assurance that the equipment would 
reasonably be expected to monitor accurately.
    (i) Install either an organic monitoring device equipped with a 
continuous recorder;
    (ii) Where an absorber is the final recovery device in the recovery 
system, a scrubbing liquid temperature monitoring device and a specific 
gravity monitoring device, each equipped with a continuous recorder 
shall be used;
    (iii) Where a condenser is the final recovery device in the 
recovery system, a condenser exit (product side) temperature monitoring 
device equipped with a continuous recorder shall be used;
    (iv) Except as specified in paragraph (a)(5)(v) of this section, 
where a carbon adsorber is the final recovery device in the recovery 
system, an integrating regeneration stream flow monitoring device 
having an accuracy of 10 percent or better, capable of 
recording the total regeneration stream mass or volumetric flow for 
each regeneration cycle; and a carbon bed temperature monitoring 
device, capable of recording the carbon bed temperature after each 
regeneration and within 15 minutes of completing any cooling cycle 
shall be used.
    (v) Beginning no later than the compliance dates specified in Sec.  
63.100(k)(10), if the owner or operator vents emissions through a 
closed vent system to an adsorber(s) that cannot be regenerated or a 
regenerative adsorber(s) that is regenerated offsite, then the owner or 
operator must install a system of two or more adsorber units in series 
and comply with the requirements specified in paragraphs (a)(5)(v)(A) 
through (C) of this section.
    (A) Conduct an initial performance test or design evaluation of the 
adsorber and establish the breakthrough limit and adsorber bed life.
    (B) Monitor the HAP or total organic compound (TOC) concentration 
through a sample port at the outlet of the first adsorber bed in series 
according to the schedule in paragraph (a)(5)(v)(C)(2) of this section. 
The owner or operator must measure the concentration of HAP or TOC 
using either a portable analyzer, in accordance with Method 21 of 
appendix A-7 to part 60 of this chapter using methane, propane, 
isobutylene, or the primary HAP being controlled as the calibration gas 
or Method 25A of part 60, appendix A-7, using methane, propane, or the 
primary HAP being controlled as the calibration gas.
    (C) Comply with paragraph (a)(5)(v)(C)(1) of this section and 
comply with the monitoring frequency according to paragraph 
(a)(5)(v)(C)(2) of this section.
    (1) The first adsorber in series must be replaced immediately when 
breakthrough, as defined in Sec.  63.101, is detected between the first 
and second adsorber. The original second adsorber (or a fresh canister) 
will become the new first adsorber and a fresh adsorber will become the 
second adsorber. For purposes of this paragraph, ``immediately'' means 
within 8 hours of the detection of a breakthrough for adsorbers of 55 
gallons or less, and within 24 hours of the detection of a breakthrough 
for adsorbers greater than 55 gallons. The owner or operator must 
monitor at the outlet of the first adsorber within 3 days of 
replacement to confirm it is performing properly.
    (2) Based on the adsorber bed life established according to 
paragraph (a)(5)(v)(A) of this section and the date the adsorbent was 
last replaced, conduct monitoring to detect breakthrough at least 
monthly if the adsorbent has more than 2 months of life remaining, at 
least weekly if the adsorbent has between 2 months and 2 weeks of life 
remaining, and at least daily if the adsorbent has 2 weeks or less of 
life remaining.
    (6) Where sorbent injection is used, the following monitoring 
equipment is required for the sorbent injection system:
    (i) A sorbent injection rate monitoring device (e.g., weigh belt, 
weigh hopper, hopper flow measurement device) installed in a position 
that provides a representative measurement equipped with a continuous 
recorder to monitor the sorbent injection rate; and
    (ii) A flow measurement device equipped with a continuous recorder 
to monitor the carrier gas flow rate.
    (b) Except as specified in Sec.  63.113(a)(4), each owner or 
operator of a process vent with a TRE index value greater than 1.0 as 
specified under Sec.  63.113(a)(3) or (d) that uses one or more 
recovery devices shall install either an organic monitoring device 
equipped with a continuous recorder or the monitoring equipment 
specified in paragraph (b)(1), (2), or (3) of this section, depending 
on the type of recovery device used. All monitoring equipment shall be 
installed, calibrated, and maintained according to the manufacturer's 
specifications or other written procedures that provide adequate 
assurance that the equipment would reasonably be expected to monitor 
accurately. Monitoring is not required for process vents with TRE index 
values greater than 4.0 as specified in Sec.  63.113(e).
    (1) Where an absorber is the final recovery device in the recovery 
system, a scrubbing liquid temperature monitoring device and a specific 
gravity monitoring device, each equipped with a continuous recorder 
shall be used;

[[Page 43181]]

    (2) Where a condenser is the final recovery device in the recovery 
system, a condenser exit (product side) temperature monitoring device 
equipped with a continuous recorder shall be used;
    (3) Where a carbon adsorber is the final recovery device in the 
recovery system, an integrating regeneration stream flow monitoring 
device having an accuracy of 10 percent or better, capable 
of recording the total regeneration stream mass or volumetric flow for 
each regeneration cycle; and a carbon bed temperature monitoring 
device, capable of recording the carbon bed temperature after each 
regeneration and within 15 minutes of completing any cooling cycle 
shall be used.
    (c) An owner or operator of a process vent may request approval to 
monitor parameters other than those listed in paragraph (a) or (b) of 
this section. The request shall be submitted according to the 
procedures specified in Sec.  63.151(f) or Sec.  63.152(e) of this 
subpart. Approval shall be requested if the owner or operator:
    (1) Uses a combustion device other than an incinerator, boiler, 
process heater, or flare; or
    (2) Except as specified in Sec.  63.113(a)(4), maintains a TRE 
greater than 1.0 but less than or equal to 4.0 without a recovery 
device or with a recovery device other than the recovery devices listed 
in paragraphs (a) and (b) of this section; or
    (3) Uses one of the combustion or recovery or recapture devices 
listed in paragraphs (a) and (b) of this section, but seeks to monitor 
a parameter other than those specified in paragraphs (a) and (b) of 
this section.
    (d) The owner or operator of a process vent shall comply with 
paragraphs (d)(1) or (2) and (d)(3) of this section for any bypass line 
between the origin of the gas stream (i.e., at an air oxidation 
reactor, distillation unit, or reactor as identified in Sec.  
63.107(b)) and the point where the gas stream reaches the process vent, 
as described in Sec.  63.107, that could divert the gas stream directly 
to the atmosphere. Except as specified in paragraph (d)(3)(ii) of this 
section, equipment such as low leg drains, high point bleeds, analyzer 
vents, open-ended valves or lines, and pressure relief valves needed 
for safety purposes are not subject to this paragraph (d).
    (1) Properly install, maintain, and operate a flow indicator that 
takes a reading at least once every 15 minutes. Records shall be 
generated as specified in Sec.  63.118(a)(3). The flow indicator shall 
be installed at the entrance to any bypass line that could divert the 
gas stream to the atmosphere; or
    (2) Secure the bypass line valve in the non-diverting position with 
a car-seal or a lock-and-key type configuration. A visual inspection of 
the seal or closure mechanism shall be performed at least once every 
month to ensure that the valve is maintained in the non-diverting 
position and the gas stream is not diverted through the bypass line
    (3) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10):
    (i) The use of a bypass line at any time on a closed vent system to 
divert emissions (subject to the emission standards in Sec.  63.112) to 
the atmosphere or to a control device not meeting the requirements 
specified in this subpart is an emissions standards violation.
    (ii) The last sentence in paragraph (d) of this section no longer 
applies. Instead, the exemptions specified in paragraphs (d)(3)(ii)(A) 
and (B) of this section apply.
    (A) Except for pressure relief devices subject to Sec.  
63.165(e)(4) of subpart H of this part, equipment such as low leg 
drains and equipment subject to the requirements of subpart H of this 
part are not subject to this paragraph (d) of this section.
    (B) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in Sec.  60.482-
6(a)(2), (b), and (c) of this chapter or follow requirements codified 
in another regulation that are the same as Sec.  60.482-6(a)(2), (b), 
and (c) are not subject to this paragraph (d).
    (e) The owner or operator shall establish a range that indicates 
proper operation of the control or recovery device for each parameter 
monitored under paragraphs (a), (b), and (c) of this section based on 
the results of the most recent performance test. In order to establish 
the range, the information required in Sec.  63.152(b) shall be 
submitted in the Notification of Compliance Status or the operating 
permit application or amendment. The range may be based upon a prior 
performance test conducted for determining compliance with a regulation 
promulgated by the EPA, and the owner or operator is not required to 
conduct an initial performance test under Sec.  63.116, if the prior 
performance test was conducted using the same methods specified in 
Sec.  63.116 and either no process changes have been made since the 
test, or the owner or operator can demonstrate that the results of the 
performance test, with or without adjustments, reliably demonstrate 
compliance despite process changes. Subsequent performance tests must 
be conducted according to Sec.  63.103(b)(1).

0
59. Amend Sec.  63.115 by revising paragraphs (a) introductory text, 
(b) introductory text, (c) introductory text, (d) introductory text, 
(e) introductory text and (f) introductory text and adding paragraph 
(g) to read as follows:


Sec.  63.115  Process vent provisions--methods and procedures for 
process vent group determination.

    (a) For purposes of determining vent stream flow rate, total 
organic HAP or total organic carbon concentration or TRE index value as 
applicable, as specified under paragraph (b), (c), or (d) of this 
section, the sampling site shall be after the last recovery device (if 
any recovery devices are present) but prior to the inlet of any control 
device that is present and prior to release to the atmosphere.
* * * * *
    (b) Except as specified in paragraph (g) of this section, to 
demonstrate that a vent stream flow rate is less than 0.005 standard 
cubic meter per minute in accordance with the Group 2 process vent 
definition of this subpart, the owner or operator shall measure flow 
rate by the following procedures:
* * * * *
    (c) Except as specified in paragraph (g) of this section, each 
owner or operator seeking to demonstrate that a vent stream has an 
organic HAP concentration below 50 parts per million by volume in 
accordance with the Group 2 process vent definition of this subpart 
shall measure either total organic HAP or TOC concentration using the 
following procedures:
* * * * *
    (d) Except as specified in Sec.  63.113(a)(4), to determine the TRE 
index value, the owner or operator shall conduct a TRE determination 
and calculate the TRE index value according to the procedures in 
paragraph (d)(1) or (2) of this section and the TRE equation in 
paragraph (d)(3) of this section.
* * * * *
    (e) Except as specified in Sec.  63.113(a)(4), the owner or 
operator of a Group 2 process vent shall recalculate the TRE index 
value, flow, or organic hazardous air pollutants concentration for each 
process vent, as necessary to determine whether the vent is Group 1 or 
Group 2, whenever process changes are made that could reasonably be 
expected to change the vent to a Group 1 vent. Examples of process 
changes include, but are not limited to, changes in production 
capacity, production rate, feedstock type, or catalyst type, or 
whenever there is replacement, removal, or addition of recovery 
equipment. For purposes of this paragraph, process

[[Page 43182]]

changes do not include: Process upsets; unintentional, temporary 
process changes; and changes that are within the range on which the 
original TRE calculation was based.
* * * * *
    (f) Except as specified in Sec.  63.113(a)(4), notwithstanding any 
other provisions of this subpart, in any case where a process vent 
includes one or more gas streams that are not from a source subject to 
this subpart (hereafter called ``non-HON streams'' for purposes of this 
paragraph), and one or more gas streams that meet the criteria in Sec.  
63.107(b) through (h) or the criteria in Sec.  63.107(i) (hereafter 
called ``HON streams'' for purposes of this paragraph), the owner or 
operator may elect to comply with paragraphs (f)(1) through (3) of this 
section.
* * * * *
    (g) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraphs 
(b) and (c) of this section no longer apply. Instead, to demonstrate 
that a vent stream total organic HAP mass flow rate is less than 1.0 
pound per hour in accordance with the Group 2 process vent definition 
of this subpart, the owner or operator must use the following 
procedures:
    (1) The sampling site must be selected as specified in paragraph 
(a) of this section.
    (2) Method 18 or Method 25A of appendices A-6 and A-7 to 40 CFR 
part 60 of this chapter, respectively, or Method 320 of appendix A to 
this part must be used to measure concentration. ASTM D6420-18 
(incorporated by reference, see Sec.  [thinsp]63.14) may also be used 
in lieu of Method 18 or Method 320, if the target compounds are all 
known and are all listed in section 1.1 of ASTM D6420-18 as measurable; 
ASTM D6420-18 must not be used for methane and ethane; and ASTM D6420-
18 may not be used as a total VOC method.
    (3) Where Method 18 of appendix A-6 to part 60 of this chapter, 
Method 320 of appendix A to this part, or ASTM D6420-18 is used, the 
following procedures must be used to calculate the total organic HAP 
mass flow rate:
    (i) The minimum sampling time for each run must be 1 hour in which 
either an integrated sample or four grab samples must be taken. If grab 
sampling is used, then the samples must be taken at approximately equal 
intervals in time, such as 15 minute intervals during the run.
    (ii) The mass rate of total organic HAP for each run must be 
computed using the following equation:
Equation 6 to Paragraph (g)(3)(ii)
[GRAPHIC] [TIFF OMITTED] TR16MY24.056

Where:

EHAP = Emission rate of total organic HAP, lb/hr.
K = 1.675 x 10-7 (parts per million)-1 (lb-
mole per standard cubic feet) (minutes per hour), where standard 
temperature is 68 [deg]F (20 [deg]C).
Q = Flowrate of gas stream, dry standard cubic feet per minute), 
where standard temperature is 68 [deg]F (20 [deg]C), determined 
using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A, as 
appropriate. The flowrate may be based solely on an engineering 
assessment if measurements cannot be made with EPA reference 
methods.
Cj = Concentration of organic compound j in the gas 
stream as measured by Method 18 of appendix A-6 to 40 CFR part 60, 
Method 320 of appendix A to this part, or ASTM D6420-18 
(incorporated by reference, see Sec.  63.14), ppmv dry basis. The 
concentration may be based solely on an engineering assessment if 
measurements cannot be made with EPA reference methods.
Mi = Molecular weight of organic compound j, lb/lb-mole.
j = Individual organic HAP compound in the gas stream. The list of 
organic HAPs is provided in table 2 of subpart F of this part.
n = Number of organic HAP compounds j in the gas stream.

    (iii) The owner or operator must demonstrate that the emission rate 
of total organic HAP is less than 1.0 pound per hour for the vent 
stream to be considered a Group 2 process vent.
    (4) Where Method 25A of appendix A-7 to part 60 of this chapter is 
used, the following procedures must be used to calculate parts per 
million by volume TOC concentration:
    (i) Method 25A of appendix A-7 to part 60 of this chapter must be 
used only if a single organic HAP compound is greater than 50 percent 
of total organic HAP, by volume, in the vent stream.
    (A) This organic HAP must be used as the calibration gas for Method 
25A of appendix A-7 to part 60 of this chapter.
    (B) Use of Method 25A of appendix A-7 to part 60 of this chapter is 
acceptable if the response from the high-level calibration gas is at 
least 20 times the standard deviation of the response from the zero 
calibration gas when the instrument is zeroed on the most sensitive 
scale.
    (ii) The span value for Method 25A of appendix A-7 to part 60 of 
this chapter must be equal to approximately twice the expected 
concentration of TOC in the gas stream.
    (iii) The minimum sampling time for each run must be 1 hour. The 
results must be corrected to a dry basis. You must use Method 4 of 
appendix A-3 to part 60 of this chapter to convert the Method 25A 
results to a dry basis.
    (iv) The mass rate of TOC for each run must be computed using the 
following equation:
Equation 7 to Paragraph (g)(4)(iv)
[GRAPHIC] [TIFF OMITTED] TR16MY24.057

Where:

ETOC = Emission rate of TOC, lb/hr.
K = 1.675 x 10-7 (parts per million)-1 (lb-
mole per standard cubic feet) (minutes per hour), where standard 
temperature is 68 [deg]F (20 [deg]C).
C = Concentration of TOC in the gas stream as measured by Method 25A 
of appendix A to part 60 of this chapter ppmv dry basis. The 
concentration may be based solely on an engineering assessment if 
measurements cannot be made with EPA reference methods.
M = Molecular weight of the organic HAP used as the calibration gas, 
lb/lb-mole.
Q = Flowrate of gas stream, dry standard cubic feet per minute), 
where standard temperature is 68 [deg]F (20 [deg]C), determined 
using Method 2, 2A, 2C, or 2D of appendix A-1 to part 60 of this 
chapter, as appropriate. The flowrate may be based solely on an 
engineering

[[Page 43183]]

assessment if measurements cannot be made with EPA reference 
methods.

    (v) The owner or operator must demonstrate that the emission rate 
of TOC is less than 1.0 pound per hour for the vent stream to be 
considered a Group 2 process vent.
    (5) The requirements specified in paragraphs (g)(1) through (4) of 
this section for an initial measurement or initial performance test do 
not apply if the conditions specified in paragraphs (g)(5)(i) through 
(iv) of this section are met for a previously conducted measurement or 
performance test.
    (i) No changes have been made to the process since the time of the 
measurement or performance test;
    (ii) The operating conditions and test methods used during 
measurement or performance test conform to the requirements in 
paragraphs (g)(1) through (4) of this section;
    (iii) The control device and process parameter values established 
during the previously conducted measurement or performance test are 
used to demonstrate continuous compliance with the related requirements 
of this subpart, if applicable; and
    (iv) The previously conducted measurement or performance test was 
completed within the last 60 months.

0
60. Amend Sec.  63.116 by:
0
a. Revising paragraphs (a) introductory text, (b)(3) through (5), (c) 
introductory text, (c)(3) introductory text, (c)(3)(iii)(A), (c)(4) 
introductory text, (c)(4)(ii)(B), and (d) introductory text; and
0
b. Adding paragraphs (f) through (h).
    The revisions and additions read as follows:


Sec.  63.116  Process vent provisions--performance test methods and 
procedures to determine compliance.

    (a) When a flare is used to comply with Sec.  63.113(a)(1), the 
owner or operator shall comply with paragraphs (a)(1) through (3) of 
this section except as specified in Sec.  63.108(a). The owner or 
operator is not required to conduct a performance test to determine 
percent emission reduction or outlet organic HAP or TOC concentration.
* * * * *
    (b) * * *
    (3) A control device for which a performance test was conducted for 
determining compliance with a regulation promulgated by the EPA and the 
test was conducted using the same methods specified in this section and 
either no process changes have been made since the test, or the owner 
or operator can demonstrate that the results of the performance test, 
with or without adjustments, reliably demonstrate compliance despite 
process changes is not required to conduct an initial performance test. 
Subsequent performance tests must be conducted according to Sec.  
63.103(b)(1).
    (4) A boiler or process heater burning hazardous waste for which 
the owner or operator:
    (i) Has been issued a final permit under part 270 of this chapter 
and complies with the requirements of part 266, subpart H, of this 
chapter;
    (ii) Has certified compliance with the interim status requirements 
of part 266, subpart H, of this chapter;
    (iii) Meets the requirement specified in paragraph (b)(4)(v) of 
this section, and has submitted a Notification of Compliance under 
Sec.  63.1207(j) and complies with the requirements of subpart EEE of 
this part; or
    (iv) Meets the requirement specified in paragraph (b)(4)(v) of this 
section, complies with subpart EEE of this part, and will submit a 
Notification of Compliance under Sec.  63.1207(j) by the date the owner 
or operator would have been required to submit the initial performance 
test report for this subpart.
    (v) The owner and operator may not waive performance testing 
pursuant to Sec.  63.1207(d)(4) and each performance test required by 
Sec.  63.1207(d) must show compliance with the dioxins and furans 
emission limit specified in Sec.  63.113(a)(5).
    (5) A hazardous waste incinerator for which the owner or operator:
    (i) Has been issued a final permit under 40 CFR part 270 and 
complies with the requirements of part 264, subpart O, of this chapter;
    (ii) Has certified compliance with the interim status requirements 
of part 265, subpart O, of this chapter.
    (iii) Meets the requirement specified in paragraph (b)(5)(v) of 
this section, and has submitted a Notification of Compliance under 
Sec.  63.1207(j) and complies with the requirements subpart EEE of this 
part; or
    (iv) Meets the requirement specified in paragraph (b)(5)(v) of this 
section, complies with the requirements subpart EEE of this part, and 
will submit a Notification of Compliance under Sec.  63.1207(j) by the 
date the owner or operator would have been required to submit the 
initial performance test report for this subpart.
    (v) The owner and operator may not waive performance testing 
pursuant to Sec.  63.1207(d)(4) and each performance test required by 
Sec.  63.1207(d) must show compliance with the dioxins and furans 
emission limit specified in Sec.  63.113(a)(5).
    (c) Except as provided in paragraphs (a) and (b) of this section, 
an owner or operator using a control device to comply with the organic 
HAP concentration limit or percent reduction efficiency requirements in 
Sec.  63.113(a)(2) of this subpart shall conduct performance tests 
using the procedures in paragraphs (c)(1) through (4) of this section 
according to the schedule in Sec.  63.103(b)(1) of subpart F of this 
part. The organic HAP concentration and percent reduction may be 
measured as either total organic HAP or as TOC minus methane and ethane 
according to the procedures specified.
* * * * *
    (3) To determine compliance with the 20 parts per million by volume 
total organic HAP limit in Sec.  63.113(a)(2) of this subpart, the 
owner or operator shall use Method 18 of appendix A-6 to part 60 of 
this chapter to measure either TOC minus methane and ethane or total 
organic HAP. ASTM D6420-18 (incorporated by reference, see Sec.  63.14) 
may also be used in lieu of Method 18, if the target compounds are all 
known and are all listed in Section 1.1 of ASTM D6420-18 as measurable; 
ASTM D6420-18 must not be used for methane and ethane; and ASTM D6420-
18 may not be used as a total VOC method. Alternatively, any other 
method or data that has been validated according to the applicable 
procedures in Method 301 of appendix A of this part, may be used. The 
following procedures shall be used to calculate parts per million by 
volume concentration, corrected to 3 percent oxygen:
* * * * *
    (iii) * * *
    (A) Method 3A of appendix A-2 to part 60 of this chapter or the 
manual method in ANSI/ASME PTC 19.10-1981 (incorporated by reference, 
see Sec.  [thinsp]63.14) shall be used to determine the oxygen 
concentration (%O2d). The samples shall be taken during the same time 
that the TOC (minus methane or ethane) or total organic HAP samples are 
taken.
* * * * *
    (4) To determine compliance with the 98 percent reduction 
requirement of Sec.  63.113(a)(2), the owner or operator shall use 
Method 18 of appendix A-6 to part 60 of this chapter; alternatively, 
any other method or data that has been validated according to the 
applicable procedures in Method 301 of appendix A to this part may be 
used. ASTM D6420-18 (incorporated by reference, see Sec.  63.14) may 
also be used in lieu of Method 18, if the target compounds are all 
known and are all listed in section 1.1 of ASTM D6420-18 as measurable; 
ASTM D6420-18 must not be used for

[[Page 43184]]

methane and ethane; and ASTM D6420-18 may not be used as a total VOC 
method. The following procedures shall be used to calculate percent 
reduction efficiency:
* * * * *
    (ii) * * *
    (B) Where the mass rate of TOC is being calculated, all organic 
compounds (minus methane and ethane) measured by Method 18 of appendix 
A-6 to part 60 of this chapter or ASTM D6420-18 (incorporated by 
reference, see Sec.  63.14) are summed using the equation in paragraph 
(c)(4)(ii)(A) of this section.
* * * * *
    (d) An owner or operator using a combustion device followed by a 
scrubber or other halogen reduction device to control halogenated vent 
streams in compliance with Sec.  63.113(c)(1) shall conduct performance 
tests to determine compliance with the control efficiency or emission 
limits for hydrogen halides and halogens according to the schedule in 
Sec.  63.103(b)(1).
* * * * *
    (f) To demonstrate compliance with the emission limits and work 
practice standards specified in Sec.  63.113(j) for process vents in 
ethylene oxide service, owners and operators must meet the requirements 
specified in Sec.  63.124.
    (g) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), an owner or 
operator using a recapture device to comply with the organic HAP 
concentration limit or percent reduction efficiency requirements in 
Sec.  63.113(a)(2) shall conduct a performance test using the same 
procedures specified in paragraph (c) of this section, except the term 
``recapture device'' is substituted for ``control device.''
    (h) To demonstrate compliance with the dioxins and furans emission 
limit specified in Sec.  63.113(a)(5), owners and operators must 
conduct performance tests using the procedures in paragraphs (h)(1) 
through (6) of this section according to the schedule in Sec.  
63.103(b)(1).
    (1) The performance test must consist of three test runs. Collect 
at least 3 dry standard cubic meters of gas per test run.
    (2) Use Method 1 or 1A of appendix A-1 to 40 CFR part 60 to select 
the sampling sites at the sampling location. The sampling location must 
be at the outlet of the final control device.
    (3) Determine the gas volumetric flowrate using Method 2, 2A, 2C, 
or 2D of appendix A-1 to part 60 of this chapter.
    (4) Use Method 4 of appendix A-3 to part 60 of this chapter to 
convert the volumetric flowrate to a dry basis.
    (5) Measure the concentration of each tetra- through octa-
chlorinated dioxin and furan congener emitted using Method 23 of 
appendix A-7 to part 60 of this chapter.
    (i) For each dioxin and furan congener, multiply the congener 
concentration by its corresponding toxic equivalency factor specified 
in table 38 to this subpart. For determination of toxic equivalency, 
zero may be used for congeners with a concentration less than the 
estimated detection limit (EDL). For congeners with estimated maximum 
pollutant concentration (EMPC) results, if the value is less than the 
EDL, zero may be used. Otherwise, the EMPC value must be used in the 
calculation of toxic equivalency.
    (ii) Sum the products calculated in accordance with paragraph 
(h)(5)(i) of this section to obtain the total concentration of dioxins 
and furans emitted in terms of toxic equivalency.
    (6) The concentration of dioxins and furans shall be corrected to 3 
percent oxygen. Use Method 3A of 40 CFR part 60, appendix A, or the 
manual method in ANSI/ASME PTC 19.10-1981 (incorporated by reference, 
see Sec.  [thinsp]63.14) to determine the oxygen concentration (%O2d). 
The oxygen concentration must be determined concurrently with Method 23 
of appendix A-7 to part 60 of this chapter. The concentration corrected 
to 3 percent oxygen (Cc) shall be computed using the following 
equation:
[GRAPHIC] [TIFF OMITTED] TR16MY24.058

Where:

Cc = Concentration of dioxins and furans corrected to 3 
percent oxygen, dry basis, nanograms per standard cubic meter.
Cm = Concentration of dioxins and furans, dry basis, 
nanograms per standard cubic meter.
%O2d = Concentration of oxygen, dry basis, percent by volume.

0
61. Revise and republish Sec.  63.117 to read as follows:


Sec.  63.117  Process vent provisions--reporting and recordkeeping 
requirements for group and TRE determinations and performance tests.

    (a) Except as specified in Sec.  63.113(a)(4), each owner or 
operator subject to the control provisions for Group 1 process vents in 
Sec.  63.113(a) or the provisions for Group 2 process vents with a TRE 
index value greater than 1.0 but less than or equal to 4.0 in Sec.  
63.113(d) shall:
    (1) Keep an up-to-date, readily accessible record of the data 
specified in paragraphs (a)(4) through (10) of this section, as 
applicable, and
    (2) Include the data in paragraphs (a)(4) through (10) of this 
section in the Notification of Compliance Status report as specified in 
Sec.  63.152(b) of this subpart.
    (3) Except as specified in Sec.  63.113(a)(4), if any subsequent 
TRE determinations or performance tests are conducted after the 
Notification of Compliance Status has been submitted, report the data 
in paragraphs (a)(4) through (a)(10) of this section in the next 
Periodic Report as specified in Sec.  63.152(c).
    (4) Record and report the following when using a combustion device 
to achieve a 98 weight percent reduction in organic HAP or an organic 
HAP concentration of 20 parts per million by volume, as specified in 
Sec.  63.113(a)(2):
    (i) The parameter monitoring results for incinerators, catalytic 
incinerators, boilers or process heaters specified in table 3 of this 
subpart, and averaged over the same time period of the performance 
testing.
    (ii) For an incinerator, the percent reduction of organic HAP or 
TOC achieved by the incinerator determined as specified in Sec.  
63.116(c), or the concentration of organic HAP or TOC (parts per 
million by volume, by compound) determined as specified in Sec.  
63.116(c) at the outlet of the incinerator on a dry basis corrected to 
3 percent oxygen.
    (iii) For a boiler or process heater, a description of the location 
at which the vent stream is introduced into the boiler or process 
heater.
    (iv) For a boiler or process heater with a design heat input 
capacity of less than 44 megawatts and where the vent stream is 
introduced with combustion air or used as a secondary fuel and is not 
mixed with the primary fuel, the percent reduction of organic HAP or

[[Page 43185]]

TOC, or the concentration of organic HAP or TOC (parts per million by 
volume, by compound) determined as specified in Sec.  63.116(c) at the 
outlet of the combustion device on a dry basis corrected to 3 percent 
oxygen.
    (5) Except as specified in Sec.  63.108)(a), record and report the 
following when using a flare to comply with Sec.  63.113(a)(1):
    (i) Flare design (i.e., steam-assisted, air-assisted, or non-
assisted);
    (ii) All visible emission readings, heat content determinations, 
flow rate measurements, and exit velocity determinations made during 
the compliance determination required by Sec.  63.116(a); and
    (iii) All periods during the compliance determination when the 
pilot flame is absent.
    (6) Record and report the following when using a scrubber following 
a combustion device to control a halogenated vent stream:
    (i) The percent reduction or scrubber outlet mass emission rate of 
total hydrogen halides and halogens as specified in Sec.  63.116(d);
    (ii) The pH of the scrubber effluent; and
    (iii) The scrubber liquid to gas ratio.
    (7) Except as specified in Sec.  63.113(a)(4), record and report 
the following when achieving and maintaining a TRE index value greater 
than 1.0 but less than 4.0 as specified in Sec.  63.113(a)(3) or (d):
    (i) The parameter monitoring results for absorbers, condensers, or 
carbon adsorbers, as specified in table 4 to this subpart, and averaged 
over the same time period of the measurements of vent stream flow rate 
and concentration used in the TRE determination (both measured while 
the vent stream is normally routed and constituted), and
    (ii) The measurements and calculations performed to determine the 
TRE index value of the vent stream.
    (8) Record and report the halogen concentration in the vent stream 
determined according to the procedures specified in Sec.  
63.115(d)(2)(v).
    (9) When using a recapture device to achieve a 98 weight percent 
reduction in organic HAP or an organic HAP concentration of 20 parts 
per million by volume, as specified in Sec.  63.113(a)(2), record and 
report the parameter monitoring results for absorbers, condensers, or 
carbon adsorbers, as specified in table 3 of this subpart, and averaged 
over the same time period of the performance testing.
    (10) Record and report the following when using a control device, 
recapture device, or recovery device to meet the dioxins and furans 
emissions limit.
    (i) The parameter monitoring results, as specified in table 3 of 
this subpart, for the applicable device and averaged over the same time 
period of the performance testing.
    (ii) The dioxins and furans concentration on a toxic equivalency 
basis (nanograms per standard cubic meter on a dry basis corrected to 3 
percent oxygen) determined as specified in Sec.  63.116(h).
    (b) Except as specified in Sec.  63.113(a)(4), the owner or 
operator of a Group 2 process vent with a TRE index greater than 4.0 as 
specified in Sec.  63.113(e), shall maintain records and submit as part 
of the Notification of Compliance Status specified in Sec.  63.152, 
measurements, engineering assessments, and calculations performed to 
determine the TRE index value of the vent stream. Documentation of 
engineering assessments shall include all data, assumptions, and 
procedures used for the engineering assessments, as specified in Sec.  
63.115(d)(1).
    (c) Except as specified in paragraph (g) of this section, each 
owner or operator who elects to demonstrate that a process vent is a 
Group 2 process vent based on a flow rate less than 0.005 standard 
cubic meter per minute must submit to the Administrator the flow rate 
measurement using methods and procedures specified in Sec.  63.115(a) 
and (b) with the Notification of Compliance Status specified in Sec.  
63.152.
    (d) Except as specified in paragraph (g) of this section, each 
owner or operator who elects to demonstrate that a process vent is a 
Group 2 process vent based on organic HAP or TOC concentration less 
than 50 parts per million by volume must submit to the Administrator an 
organic HAP or TOC concentration measurement using the methods and 
procedures specified in Sec.  63.115(a) and (c) with the Notification 
of Compliance Status specified in Sec.  63.152.
    (e) If an owner or operator uses a control or recovery device other 
than those listed in tables 3 and 4 to this subpart or requests 
approval to monitor a parameter other than those specified in tables 3 
and 4 to this subpart, the owner or operator shall submit a description 
of planned reporting and recordkeeping procedures as required under 
Sec.  63.151(f) or Sec.  63.152(e). The Administrator will specify 
appropriate reporting and recordkeeping requirements as part of the 
review of the permit application or by other appropriate means.
    (f) For each parameter monitored according to tables 3 or 4 to this 
subpart or paragraph (e) of this section, the owner or operator shall 
establish a range for the parameter that indicates proper operation of 
the control or recovery device. In order to establish the range, the 
information required in Sec.  63.152(b) shall be submitted in the 
Notification of Compliance Status or the operating permit application 
or amendment.
    (g) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraphs 
(c) and (d) of this section no longer apply. Instead, each owner or 
operator demonstrating that a process vent is a Group 2 process vent 
based on total organic HAP mass flow rate less than 1.0 pound per hour 
must submit to the Administrator a total organic HAP measurement using 
the methods and procedures specified in Sec.  63.115(g) with the 
Notification of Compliance Status specified in Sec.  63.152.

0
62. Revise and republish Sec.  63.118 to read as follows:


Sec.  63.118  Process vent provisions--periodic reporting and 
recordkeeping requirements.

    (a) Each owner or operator using a control device to comply with 
Sec.  63.113(a)(1), (2), or (5) shall keep the following records up-to-
date and readily accessible:
    (1) Continuous records of the equipment operating parameters 
specified to be monitored under Sec.  63.114(a) to this subpart and 
listed in table 3 to this subpart or specified by the Administrator in 
accordance with Sec.  63.114(c) and Sec.  63.117(e). For flares, the 
hourly records and records of pilot flame outages specified in table 3 
to this subpart shall be maintained in place of continuous records.
    (2) Records of the daily average value of each continuously 
monitored parameter for each operating day determined according to the 
procedures specified in Sec.  63.152(f). For flares complying with 
Sec.  63.11(b), records of the times and duration of all periods during 
which all pilot flames are absent shall be kept rather than daily 
averages. For flares complying with Sec.  63.108, the owner or operator 
must comply with the recordkeeping requirements specified therein.
    (3) Hourly records of whether the flow indicator specified under 
Sec.  63.114(d)(1) was operating and whether a diversion was detected 
at any time during the hour, as well as records of the times and 
durations of all periods when the gas stream is diverted to the 
atmosphere or the monitor is not operating.
    (4) Where a seal mechanism is used to comply with Sec.  
63.114(d)(2), hourly records of flow are not required. In such cases, 
the owner or operator shall record that the monthly visual inspection 
of

[[Page 43186]]

the seals or closure mechanism has been done, and shall record the 
duration of all periods when the seal mechanism is broken, the bypass 
line valve position has changed, or the key for a lock-and-key type 
lock has been checked out, and records of any car-seal that has broken.
    (5) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), the owner 
or operator must comply with this paragraph in addition to the 
requirements in paragraphs (a)(1) through (4) of this section. For each 
flow event from a bypass line subject to the requirements in Sec.  
63.114(d), the owner or operator must maintain records sufficient to 
determine whether or not the detected flow included flow requiring 
control. For each flow event from a bypass line requiring control that 
is released either directly to the atmosphere or to a control device 
not meeting the requirements in this subpart, the owner or operator 
must include an estimate of the volume of gas, the concentration of 
organic HAP in the gas and the resulting emissions of organic HAP that 
bypassed the control device using process knowledge and engineering 
estimates.
    (b) Except as specified in Sec.  63.113(a)(4), each owner or 
operator using a recovery device or other means to achieve and maintain 
a TRE index value greater than 1.0 but less than 4.0 as specified in 
Sec.  63.113(a)(3) or (d) shall keep the following records up-to-date 
and readily accessible:
    (1) Continuous records of the equipment operating parameters 
specified to be monitored under Sec.  63.114(b) to this subpart and 
listed in table 4 to this subpart or specified by the Administrator in 
accordance with Sec.  63.114(c) and Sec.  63.114(e) and
    (2) Records of the daily average value of each continuously 
monitored parameter for each operating day determined according to the 
procedures specified in Sec.  63.152(f). If carbon adsorber 
regeneration stream flow and carbon bed regeneration temperature are 
monitored, the records specified in table 4 to this subpart shall be 
kept instead of the daily averages.
    (c) Except as specified in Sec.  63.113(a)(4), each owner or 
operator subject to the provisions of this subpart and who elects to 
demonstrate compliance with the TRE index value greater than 4.0 under 
Sec.  63.113(e) or greater than 1.0 under Sec.  63.113(a)(3) or (d) 
shall keep up-to-date, readily accessible records of:
    (1) Any process changes as defined in Sec.  63.115(e); and
    (2) Any recalculation of the TRE index value pursuant to Sec.  
63.115(e).
    (d) Except as specified in paragraph (n) of this section, each 
owner or operator who elects to comply by maintaining a flow rate less 
than 0.005 standard cubic meter per minute under Sec.  63.113(f), shall 
keep up-to-date, readily accessible records of:
    (1) Any process changes as defined in Sec.  63.115(e) that increase 
the vent stream flow rate,
    (2) Any recalculation or measurement of the flow rate pursuant to 
Sec.  63.115(e), and
    (3) Except as specified in Sec.  63.113(a)(4), if the flow rate 
increases to 0.005 standard cubic meter per minute or greater as a 
result of the process change, the TRE determination performed according 
to the procedures of Sec.  63.115(d).
    (e) Except as specified in paragraph (n) of this section, each 
owner or operator who elects to comply by maintaining an organic HAP 
concentration less than 50 parts per million by volume organic HAP 
concentration under Sec.  63.113(g) shall keep up-to-date, readily 
accessible records of:
    (1) Any process changes as defined in Sec.  63.115(e) that increase 
the organic HAP concentration of the vent stream,
    (2) Any recalculation or measurement of the concentration pursuant 
to Sec.  63.115(e), and
    (3) Except as specified in Sec.  63.113(a)(4), if the organic HAP 
concentration increases to 50 parts per million by volume or greater as 
a result of the process change, the TRE determination performed 
according to the procedures of Sec.  63.115(d).
    (f) Each owner or operator who elects to comply with the 
requirements of Sec.  63.113 of this subpart shall submit to the 
Administrator Periodic Reports of the following recorded information 
according to the schedule in Sec.  63.152.
    (1) Reports of daily average values of monitored parameters for all 
operating days when the daily average values recorded under paragraphs 
(a) and (b) of this section were outside the ranges established in the 
Notification of Compliance Status or operating permit, including the 
date that the parameter was outside the range.
    (2) For Group 1 points, reports of the duration (in hours) of 
periods when monitoring data is not collected for each excursion caused 
by insufficient monitoring data as defined in Sec.  
63.152(c)(2)(ii)(A), including the start date of such periods.
    (3) Reports of the times and durations of all periods recorded 
under paragraph (a)(3) of this section when the gas stream is diverted 
to the atmosphere through a bypass line and if applicable, the 
information in paragraph (f)(7) of this section. Include the start 
date, start time and duration in hours of each period.
    (4) Reports of all periods recorded under paragraph (a)(4) of this 
section in which the seal mechanism is broken, the bypass line valve 
position has changed, or the key to unlock the bypass line valve was 
checked out and if applicable, the information in paragraph (f)(7) of 
this section. Include the start date, start time and duration in hours 
of each period.
    (5) Except as specified in paragraph (a) of Sec.  63.108, reports 
of the times and durations of all periods recorded under paragraph 
(a)(2) of this section in which all pilot flames of a flare were 
absent.
    (6) Reports of all carbon bed regeneration cycles during which the 
parameters recorded under paragraph (b)(2)(v) of this section were 
outside the ranges established in the Notification of Compliance Status 
or operating permit. Include the identification of the carbon bed, the 
monitored parameter that was outside the established range, and the 
start date, start time and duration in hours of the regeneration cycle.
    (7) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), the owner 
or operator must comply with this paragraph in addition to the 
requirements in paragraphs (f)(3) and (4) of this section. For bypass 
lines subject to the requirements in Sec.  63.114(d), the Periodic 
Report must include the start date, start time, duration in hours, 
estimate of the volume of gas in standard cubic feet, the concentration 
of organic HAP in the gas in parts per million by volume and the 
resulting mass emissions of organic HAP in pounds that bypass a control 
device. For periods when the flow indicator is not operating, report 
the start date, start time, and duration in hours.
    (8) For process vents in ethylene oxide service subject to the 
requirements of Sec.  63.124, the Periodic Report must include the 
records for periods specified in paragraph (l)(2) of this section. 
Indicate the start date and time and end date and time for each period.
    (9) For any maintenance vent release exceeding the applicable 
limits in Sec.  63.113(k)(1), the compliance report must include the 
information specified in paragraphs (f)(9)(i) through (iv) of this 
section. For the purposes of this reporting requirement, if an owner or 
operator complies with Sec.  63.113(k)(1)(iv) then the owner or 
operator must report each venting event conducted under those 
provisions and

[[Page 43187]]

include an explanation for each event as to why utilization of this 
alternative was required.
    (i) Identification of the maintenance vent and the equipment served 
by the maintenance vent.
    (ii) The date and time the maintenance vent was opened to the 
atmosphere.
    (iii) The LEL in percent, vessel pressure in psig, or mass in 
pounds of VOC in the equipment, as applicable, at the start of 
atmospheric venting. If the 5 psig vessel pressure option in Sec.  
63.113(k)(1)(ii) was used and active purging was initiated while the 
concentration of the vapor was 10 percent or greater of its LEL, also 
include the concentration of the vapors at the time active purging was 
initiated.
    (iv) An estimate of the mass in pounds of organic HAP released 
during the entire atmospheric venting event.
    (g) Whenever a process change, as defined in Sec.  63.115(e), is 
made that causes a Group 2 process vent to become a Group 1 process 
vent, the owner or operator shall submit a report within 180 calendar 
days after the process change as specified in Sec.  63.151(j). The 
report shall include:
    (1) A description of the process change;
    (2) Except as specified in Sec.  63.113(a)(4), the results of the 
recalculation of the flow rate, organic HAP concentration, and TRE 
index value required under Sec.  63.115(e) and recorded under paragraph 
(c), (d), or (e) of this section; and
    (3) A statement that the owner or operator will comply with the 
provisions of Sec.  63.113 for Group 1 process vents by the dates 
specified in subpart F of this part.
    (h) Except as specified in Sec.  63.113(a)(4), whenever a process 
change, as defined in Sec.  63.115(e), is made that causes a Group 2 
process vent with a TRE greater than 4.0 to become a Group 2 process 
vent with a TRE less than 4.0, the owner or operator shall submit a 
report within 180 calendar days after the process change. The report 
may be submitted as part of the next periodic report. The report shall 
include:
    (1) A description of the process change,
    (2) The results of the recalculation of the TRE index value 
required under Sec.  63.115(e) and recorded under paragraph (c) of this 
section, and
    (3) A statement that the owner or operator will comply with the 
requirements specified in Sec.  63.113(d).
    (i) Except as specified in Sec.  63.113(a)(4), whenever a process 
change, as defined in Sec.  63.115(e), is made that causes a Group 2 
process vent with a flow rate less than 0.005 standard cubic meter per 
minute to become a Group 2 process vent with a flow rate of 0.005 
standard cubic meter per minute or greater and a TRE index value less 
than or equal to 4.0, the owner or operator shall submit a report 
within 180 calendar days after the process change. The report may be 
submitted as part of the next periodic report. The report shall 
include:
    (1) A description of the process change,
    (2) The results of the recalculation of the flow rate and the TRE 
determination required under Sec.  63.115(e) and recorded under 
paragraph (d) of this section, and
    (3) A statement that the owner or operator will comply with the 
requirements specified in Sec.  63.113(d).
    (j) Except as specified in Sec.  63.113(a)(4), whenever a process 
change, as defined in Sec.  63.115(e), is made that causes a Group 2 
process vent with an organic HAP concentration less than 50 parts per 
million by volume to become a Group 2 process vent with an organic HAP 
concentration of 50 parts per million by volume or greater and a TRE 
index value less than or equal to 4.0, the owner or operator shall 
submit a report within 180 calendar days after the process change. The 
report may be submitted as part of the next periodic report. The report 
shall include:
    (1) A description of the process change,
    (2) The results of the recalculation of the organic HAP 
concentration and the TRE determination required under Sec.  63.115(e) 
and recorded under paragraph (e) of this section, and
    (3) A statement that the owner or operator will comply with the 
requirements specified in Sec.  63.113(d).
    (k) The owner or operator is not required to submit a report of a 
process change if one of the conditions listed in paragraph (k)(1), 
(2), (3), or (4) of this section is met.
    (1) The process change does not meet the definition of a process 
change in Sec.  63.115(e), or
    (2) The vent stream flow rate is recalculated according to Sec.  
63.115(e) and the recalculated value is less than 0.005 standard cubic 
meter per minute, or
    (3) The organic HAP concentration of the vent stream is 
recalculated according to Sec.  63.115(e) and the recalculated value is 
less than 50 parts per million by volume, or
    (4) Except as specified in Sec.  63.113(a)(4), the TRE index value 
is recalculated according to Sec.  63.115(e) and the recalculated value 
is greater than 4.0.
    (l) For process vents in ethylene oxide service subject to the 
requirements of Sec.  63.124, owners and operators must keep the 
records specified in paragraphs (l)(1) and (2) of this section in 
addition to those records specified elsewhere in this section.
    (1) For process vents, include all uncontrolled, undiluted ethylene 
oxide concentration measurements, and the calculations used to 
determine the total uncontrolled ethylene oxide mass emission rate for 
the sum of all vent gas streams.
    (2) If emissions are vented through a closed-vent system to a non-
flare control device, then the owner or operator must keep records of 
all periods during which operating values are outside of the applicable 
operating limits specified in Sec.  63.124(b)(4) through (6) when 
regulated material is being routed to the non-flare control device. The 
record must specify the identification of the control device, the 
operating parameter, the applicable limit, and the highest (for maximum 
operating limits) or lowest (for minimum operating limits) value 
recorded during the period.(m) For each maintenance vent opening 
subject to the requirements of Sec.  63.113(k), owners and operators 
must keep the applicable records specified in paragraphs (m)(1) through 
(5) of this section.
    (1) Owners and operators must maintain standard site procedures 
used to deinventory equipment for safety purposes (e.g., hot work or 
vessel entry procedures) to document the procedures used to meet the 
requirements in Sec.  63.113(k). The current copy of the procedures 
must be retained and available on-site at all times. Previous versions 
of the standard site procedures, as applicable, must be retained for 5 
years.
    (2) If complying with the requirements of Sec.  63.113(k)(1)(i), 
and the concentration of the vapor at the time of the vessel opening 
exceeds 10 percent of its LEL, identification of the maintenance vent, 
the process units or equipment associated with the maintenance vent, 
the date of maintenance vent opening, and the concentration of the 
vapor at the time of the vessel opening.
    (3) If complying with the requirements of Sec.  63.113(k)(1)(ii), 
and either the vessel pressure at the time of the vessel opening 
exceeds 5 psig or the concentration of the vapor at the time of the 
active purging was initiated exceeds 10 percent of its LEL, 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, the date of maintenance vent 
opening, the pressure of the vessel or equipment at the time

[[Page 43188]]

of discharge to the atmosphere and, if applicable, the concentration of 
the vapors in the equipment when active purging was initiated.
    (4) If complying with the requirements of Sec.  63.113(k)(1)(iii), 
records of the estimating procedures used to determine the total 
quantity of VOC in the equipment and the type and size limits of 
equipment that contain less than 50 pounds of VOC at the time of 
maintenance vent opening. For each maintenance vent opening that 
contains greater than 50 pounds of VOC for which the deinventory 
procedures specified in paragraph (m)(1) of this section are not 
followed or for which the equipment opened exceeds the type and size 
limits established in the records specified in this paragraph (m)(4), 
records that identify the maintenance vent, the process units or 
equipment associated with the maintenance vent, the date of maintenance 
vent opening, and records used to estimate the total quantity of VOC in 
the equipment at the time the maintenance vent was opened to the 
atmosphere.
    (5) If complying with the requirements of Sec.  63.113(k)(1)(iv), 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, records documenting actions taken 
to comply with other applicable alternatives and why utilization of 
this alternative was required, the date of maintenance vent opening, 
the equipment pressure and concentration of the vapors in the equipment 
at the time of discharge, an indication of whether active purging was 
performed and the pressure of the equipment during the installation or 
removal of the blind if active purging was used, the duration the 
maintenance vent was open during the blind installation or removal 
process, and records used to estimate the total quantity of VOC in the 
equipment at the time the maintenance vent was opened to the atmosphere 
for each applicable maintenance vent opening.
    (n) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraphs 
(d) and (e) of this section no longer apply. Instead, each owner or 
operator demonstrating that a process vent is a Group 2 process vent 
based on total organic HAP mass flow rate less than 1.0 pound per hour 
under Sec.  63.113(l), shall keep up-to-date, readily accessible 
records of:
    (1) Any process changes that increase the vent stream mass flow 
rate, and
    (2) Any recalculation or measurement of the mass flow rate pursuant 
to Sec.  63.115(g).

0
63. Amend Sec.  63.119 by:
0
a. Revising paragraph (a) introductory text;
0
b. Adding paragraphs (a)(5) through (7);
0
c. Revising paragraphs (b) introductory text, (b)(5) introductory text, 
and (b)(5)(ii);
0
d. Adding paragraphs (b)(5)(ix) through (xii) and (b)(7);
0
e. Revising and publishing paragraph (e);
0
f. Revising paragraphs (f)(3) and revising and republishing paragraph 
(g).
    The revisions, additions and republications read as follows:


Sec.  63.119  Storage vessel provisions--reference control technology.

    (a) For each storage vessel to which this subpart applies, the 
owner or operator shall comply with the requirements of paragraphs 
(a)(1) through (6) of this section according to the schedule provisions 
of Sec.  63.100. For each pressure vessel to which this subpart 
applies, the owner or operator must comply with the requirements of 
paragraph (a)(7) of this section.
* * * * *
    (5) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(11), if the 
storage vessel (of any capacity and vapor pressure) stores liquid 
containing ethylene oxide such that the storage vessel is considered to 
be in ethylene oxide service, as defined in Sec.  63.101, then the 
owner or operator must comply with the requirements of paragraph 
(a)(5)(i) or (ii) of this section in addition to all other applicable 
requirements specified elsewhere in this section.
    (i) Reduce emissions of ethylene oxide by venting emissions through 
a closed vent system to a flare; or
    (ii) Reduce emissions of ethylene oxide by venting emissions 
through a closed vent system to a control device that reduces ethylene 
oxide by greater than or equal to 99.9 percent by weight, or to a 
concentration less than 1 ppmv for each storage vessel vent.
    (6) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), for each 
storage vessel subject to paragraph (a)(1), (2), or (5) of this 
section, the owner or operator must comply with paragraphs (a)(6)(i) 
through (iv) of this section during storage vessel shutdown operations 
(i.e., emptying and degassing of a storage vessel) until the vapor 
space concentration in the storage vessel is less than 10 percent of 
the LEL, or the organic HAP concentration in the vapor space is equal 
to or less than of 5,000 ppmv as methane. The owner or operator must 
determine the concentration using process instrumentation or portable 
measurement devices and follow procedures for calibration and 
maintenance according to manufacturer's specifications. The owner or 
operator must determine the organic HAP concentration using Method 18 
or Method 25A of appendix A to part 60 of this chapter; or 
alternatively, any other method or data that has been validated 
according to the protocol in Method 301 of appendix A of this part.
    (i) Remove liquids from the storage vessel as much as practicable.
    (ii) Comply with one of the following:
    (A) Reduce emissions of total organic HAP by venting emissions 
through a closed vent system to a flare.
    (B) Reduce emissions of total organic HAP by 95 weight-percent by 
venting emissions through a closed vent system to any combination of 
non-flare control devices.
    (C) Reduce emissions of total organic HAP by routing emissions to a 
fuel gas system or process and meet the requirements specified in 
paragraph (f) of this section.
    (iii) Maintain records necessary to demonstrate compliance with the 
requirements in Sec.  63.102(f) of subpart F of this part including, if 
appropriate, records of existing standard site procedures used to empty 
and degas (deinventory) equipment for safety purposes.
    (iv) For floating roof storage vessels, the storage vessel may be 
opened to set up equipment (e.g., making connections to a temporary 
control device) for the shutdown operations but must not be actively 
degassed during this time period.
    (7) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), for each 
pressure vessel as defined in Sec.  63.101 that is considered a Group 1 
storage vessel (as defined in table 5 of this subpart for existing 
sources and table 6 of the subpart for new sources), you must operate 
and maintain the pressure vessel, as specified in paragraphs (a)(7)(i) 
through (v) of this section.
    (i) The pressure vessel must be designed to operate with no 
detectable emissions at all times.
    (ii) Except for connectors in ethylene oxide service, gas/vapor or 
light liquid valves in ethylene oxide service, light liquid pumps in 
ethylene oxide service,

[[Page 43189]]

and PRDs in ethylene oxide service, and except for equipment that meet 
the criteria specified in Sec.  63.168(h) and (i) (for valves in gas/
vapor service and in light liquid service) and in Sec.  63.174(f) and 
(h) (for connectors in gas/vapor service and in light liquid service), 
you must monitor each point on the pressure vessel through which total 
organic hazardous air pollutants could potentially be emitted by 
conducting initial and annual performance tests using Method 21 of 
appendix A-7 to part 60 of this chapter
    (iii) Each instrument reading greater than 500 ppmv is a violation.
    (iv) Estimate the flow rate and total regulated material emissions 
from the defect. Assume the pressure vessel has been emitting for half 
of the time since the last performance test, unless other information 
supports a different assumption.
    (v) Whenever total organic hazardous air pollutants are in the 
pressure vessel, you must operate the pressure vessel as a closed 
system that vents through a closed vent system to a control device as 
specified in paragraph (e) of this section, as applicable. For purposes 
of compliance with this paragraph, a release of total organic hazardous 
air pollutants through a pressure vessel's pressure relief device to 
the atmosphere is a violation.
    (b) The owner or operator who elects to use a fixed roof and an 
internal floating roof, as defined in Sec.  63.111, to comply with the 
requirements of paragraph (a)(1) of this section shall comply with the 
requirements specified in paragraphs (b)(1) through (7) of this 
section.

    Note: The intent of paragraphs (b)(1) and (2) of this section is 
to avoid having a vapor space between the floating roof and the 
stored liquid for extended periods. Storage vessels may be emptied 
for purposes such as routine storage vessel maintenance, 
inspections, petroleum liquid deliveries, or transfer operations. 
Storage vessels where liquid is left on walls, as bottom clingage, 
or in pools due to floor irregularity are considered completely 
empty.

* * * * *
    (5) Except as provided in paragraph (b)(5)(viii) of this section, 
each internal floating roof shall meet the specifications listed in 
paragraphs (b)(5)(i) through (vii) of this section, and (b)(5)(ix) 
through (xii) of this section.
* * * * *
    (ii) Except as specified in paragraph (b)(5)(ix) of this section, 
each opening in the internal floating roof except for leg sleeves, 
automatic bleeder vents, rim space vents, column wells, ladder wells, 
sample wells, and stub drains shall be equipped with a cover or lid. 
The cover or lid shall be equipped with a gasket.
* * * * *
    (ix) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraph 
(b)(5)(i) of this section no longer applies. Instead, each opening in 
the internal floating roof except those for automatic bleeder vents 
(vacuum breaker vents), rim space vents, leg sleeves, and deck drains 
shall be equipped with a deck cover. The deck cover shall be equipped 
with a gasket between the cover and the deck.
    (x) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), each 
opening for an unslotted guidepole shall be equipped with a pole wiper, 
and each unslotted guidepole shall be equipped with a gasketed cap on 
the top of the guidepole.
    (xi) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), each 
opening for a slotted guidepole shall be equipped with one of the 
control device configurations specified in paragraphs (b)(5)(xi)(A) and 
(B) of this section.
    (A) A pole wiper and a pole float. The wiper or seal of the pole 
float shall be at or above the height of the pole wiper.
    (B) A pole wiper and a pole sleeve.
    (xii) Each unslotted guidepole cap shall be closed at all times 
except when gauging the liquid level or taking liquid samples.
* * * * *
    (7) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), owners and 
operators that use a continuous sweep, purge, or inert blanket between 
the internal floating roof and fixed roof that causes a pressure/vacuum 
vent to remain continuously open to the atmosphere where uncontrolled 
emissions are greater than or equal to 1.0 pound per hour of total 
organic HAP must route emissions through a closed vent system and 
control device and comply with paragraph (e) of this section.
* * * * *
    (e) The owner or operator who elects to use a closed vent system 
and control device, as defined in Sec.  63.111, to comply with the 
requirements of paragraph (a)(1) or (2) of this section, or the owner 
or operator who meets the requirements specified in paragraph (b)(7) of 
this section, shall comply with the requirements specified in 
paragraphs (e)(1) through (7) of this section.
    (1) Except as provided in paragraph (e)(2) of this section, the 
control device shall be designed and operated to reduce inlet emissions 
of total organic HAP by 95 percent or greater. Except as specified in 
Sec.  63.108(a), if a flare is used as the control device, it shall 
meet the specifications described in the general control device 
requirements of Sec.  63.11(b).
    (2) If the owner or operator can demonstrate that a control device 
installed on a storage vessel on or before December 31, 1992 is 
designed to reduce inlet emissions of total organic HAP by greater than 
or equal to 90 percent but less than 95 percent, then the control 
device is required to be operated to reduce inlet emissions of total 
organic HAP by 90 percent or greater.
    (3) Except as specified in (e)(7) of this section, periods of 
planned routine maintenance of the control device, during which the 
control device does not meet the specifications of paragraph (e)(1) or 
(2) of this section, as applicable, shall not exceed 240 hours per 
year.
    (4) Except as specified in (e)(7) of this section, the 
specifications and requirements in paragraphs (e)(1) and (2) of this 
section for control devices do not apply during periods of planned 
routine maintenance.
    (5) Except as specified in (e)(7) of this section, the 
specifications and requirements in paragraphs (e)(1) and (2) of this 
section for control devices do not apply during a control system 
malfunction.
    (6) An owner or operator may use a combination of control devices 
to achieve the required reduction of total organic hazardous air 
pollutants specified in paragraph (e)(1) of this section. An owner or 
operator may use a combination of control devices installed on a 
storage vessel on or before December 31, 1992 to achieve the required 
reduction of total organic hazardous air pollutants specified in 
paragraph (e)(2) of this section.
    (7) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraphs 
(e)(3) through (5) of this section no longer apply. Instead, whenever 
gases or vapors containing total organic HAP are routed from a storage 
vessel through a closed vent system connected to a control device used 
to comply with the requirements of paragraph (e)(1) or (2) of this 
section, the control device must be operating, except the control 
device may only be bypassed for the purpose of performing planned 
routine maintenance of the control device. When the control device is 
bypassed,

[[Page 43190]]

the owner or operator must comply with paragraphs (e)(7)(i) through 
(iii) of this section.
    (i) The control device may only be bypassed when the planned 
routine maintenance cannot be performed during periods that storage 
vessel emissions are vented to the control device.
    (ii) On an annual basis, the total time that the closed-vent system 
or control device is bypassed to perform planned routine maintenance 
shall not exceed 240 hours per each calendar year.
    (iii) The level of material in the storage vessel shall not be 
increased during periods that the closed vent system or control device 
is bypassed to perform planned routine maintenance.
    (f) * * *
    (3) The fuel gas system or process shall be operating at all times 
when organic hazardous air pollutants emissions are routed to it except 
as provided in Sec.  63.102(a)(1) and in paragraphs (f)(3)(i) through 
(iv) of this section. Whenever the owner or operator bypasses the fuel 
gas system or process, the owner or operator shall comply with the 
recordkeeping requirement in Sec.  63.123(h). Bypassing is permitted if 
the owner or operator complies with one or more of the conditions 
specified in paragraphs (f)(3)(i) through (iv) of this section.
    (i) The liquid level in the storage vessel is not increased;
    (ii) The emissions are routed through a closed vent system to a 
control device complying with Sec.  63.119(e); or
    (iii) Except as specified in paragraph (f)(3)(iv) of this section, 
the total aggregate amount of time during which the emissions bypass 
the fuel gas system or process during the calendar year without being 
routed to a control device, for all reasons (except start-ups/
shutdowns/malfunctions or product changeovers of flexible operation 
units and periods when the storage vessel has been emptied and 
degassed), does not exceed 240 hours.
    (iv) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraph 
(f)(3)(iii) of this section no longer applies. Instead, if you elect to 
route emissions from storage vessels to a fuel gas system or to a 
process to comply with the requirements of paragraph (a)(1), (2), or 
(5) of this section, the fuel gas system or process may only be 
bypassed when the planned routine maintenance cannot be performed 
during periods that storage vessel emissions are vented to the fuel gas 
system or process, and the total aggregate amount of time during which 
the breathing loss emissions bypass the fuel gas system or process 
during the calendar year without being routed to a control device must 
not exceed 240 hours. The level of material in the storage vessel shall 
not be increased during periods that the fuel gas system or process is 
bypassed to perform routine maintenance.
    (g) The owner or operator who elects to vapor balance to comply 
with the requirements of paragraphs (a)(1) and (2) of this section 
shall comply with paragraphs (g)(1) through (7) of this section and the 
recordkeeping requirements of Sec.  63.123(i).
    (1) The vapor balancing system must be designed and operated to 
route organic HAP vapors displaced from loading of the storage vessel 
to the railcar, tank truck, or barge from which the storage vessel is 
filled.
    (2) Tank trucks and railcars must have a current certification in 
accordance with the U.S. Department of Transportation pressure test 
requirements of 49 CFR part 180 for tank trucks and 49 CFR 173.31 for 
railcars. Barges must have a current certification of vapor-tightness 
through testing in accordance with 40 CFR 63.565.
    (3) Hazardous air pollutants must only be unloaded from tank trucks 
or railcars when vapor collection systems are connected to the storage 
vessel's vapor collection system.
    (4) No pressure relief device on the storage vessel, or on the 
railcar or tank truck, shall open during loading or as a result of 
diurnal temperature changes (breathing losses).
    (5) Pressure relief devices must be set to no less than 2.5 psig at 
all times to prevent breathing losses. Pressure relief devices may be 
set at values less than 2.5 psig if the owner or operator provides 
rationale in the notification of compliance status report explaining 
why the alternative value is sufficient to prevent breathing losses at 
all times. The owner or operator shall comply with paragraphs (g)(5)(i) 
through (iii) of this section for each pressure relief valve.
    (i) The pressure relief valve shall be monitored quarterly using 
the method described in Sec.  63.180(b).
    (ii) An instrument reading of 500 ppmv or greater defines a leak.
    (iii) When a leak is detected, it shall be repaired as soon as 
practicable, but no later than 5 days after it is detected, and the 
owner or operator shall comply with the recordkeeping requirements of 
Sec.  63.181(d)(1) through (4).
    (6) Railcars, tank trucks, or barges that deliver HAP to a storage 
vessel must be reloaded or cleaned at a facility that utilizes the 
control techniques specified in paragraph (g)(6)(i) or (ii) of this 
section.
    (i) The railcar, tank truck, or barge must be connected to a closed 
vent system with a control device that reduces inlet emissions of HAP 
by 95 percent by weight or greater.
    (ii) A vapor balancing system designed and operated to collect 
organic HAP vapor displaced from the tank truck, railcar, or barge 
during reloading must be used to route the collected HAP vapor to the 
storage vessel from which the liquid being transferred originated.
    (7) The owner or operator of the facility where the railcar, tank 
truck, or barge is reloaded or cleaned must comply with paragraphs 
(g)(7)(i) through (iii) of this section.
    (i) Submit to the owner or operator of the storage vessel and to 
the Administrator a written certification that the reloading or 
cleaning facility will meet the requirements of this section. The 
certifying entity may revoke the written certification by sending a 
written statement to the owner or operator of the storage vessel giving 
at least 90 days notice that the certifying entity is rescinding 
acceptance of responsibility for compliance with the requirements of 
this paragraph (g)(7).
    (ii) If complying with paragraph (g)(6)(i) of this section, comply 
with the requirements for closed vent system and control device 
specified in Sec. Sec.  63.119 through 63.123. The notification and 
reporting requirements in Sec.  63.122 do not apply to the owner or 
operator of the offsite cleaning or reloading facility.
    (iii) If complying with paragraph (g)(6)(ii) of this section, keep 
the records specified in Sec.  63.123(i)(3).
    (iv) After the compliance dates specified in Sec.  63.100(k) at an 
offsite reloading or cleaning facility subject to paragraph (g) of this 
section, compliance with the monitoring, recordkeeping, and reporting 
provisions of any other subpart of this part 63 constitutes compliance 
with the monitoring, recordkeeping, and reporting provisions of 
paragraph (g)(7)(ii) or (iii) of this section. You must identify in 
your Notification of Compliance Status report required by Sec.  
63.152(b), the subpart to the part 63 with which the owner or operator 
of the reloading or cleaning facility complies.

0
64. Amend Sec.  63.120 by:
0
a. Revising paragraphs (b)(9);
0
b. Revising and republishing paragraph (d);
0
c. Revising paragraphs (e) introductory text and (e)(3); and
0
d. Adding paragraph (g).
    The revisions, addition, and republication read as follows:

[[Page 43191]]

Sec.  63.120  Storage vessel provisions--procedures to determine 
compliance.

* * * * *
    (b) * * *
    (9) The owner or operator shall notify the Administrator in writing 
at least 30 calendar days in advance of any gap measurements required 
by paragraph (b)(1) or (2) of this section to afford the Administrator 
the opportunity to have an observer present.
* * * * *
    (d) To demonstrate compliance with Sec.  63.119(e) (storage vessel 
equipped with a closed vent system and control device) using a control 
device other than a flare, the owner or operator shall comply with the 
requirements in paragraphs (d)(1) through (7) of this section, except 
as provided in paragraphs (d)(8) and (9) of this section.
    (1) Except as provided in paragraph (d)(1)(iii) of this section, 
the owner or operator shall either prepare a design evaluation, which 
includes the information specified in paragraph (d)(1)(i) of this 
section or submit the results of a performance test as described in 
paragraph (d)(1)(ii) of this section.
    (i) The design evaluation shall include documentation demonstrating 
that the control device being used achieves the required control 
efficiency during reasonably expected maximum filling rate. This 
documentation is to include a description of the gas stream which 
enters the control device, including flow and organic HAP content under 
varying liquid level conditions, and the information specified in 
paragraphs (d)(1)(i)(A) through (E) of this section, as applicable.
    (A) If the control device receives vapors, gases or liquids, other 
than fuels, from emission points other than storage vessels subject to 
this subpart, the efficiency demonstration is to include consideration 
of all vapors, gases, and liquids, other than fuels, received by the 
control device.
    (B) If an enclosed combustion device with a minimum residence time 
of 0.5 seconds and a minimum temperature of 760 [deg]C is used to meet 
the emission reduction requirement specified in Sec.  63.119 (e)(1) or 
(2), as applicable, documentation that those conditions exist is 
sufficient to meet the requirements of paragraph (d)(1)(i) of this 
section.
    (C) Except as provided in paragraph (d)(1)(i)(B) of this section, 
for thermal incinerators, the design evaluation shall include the 
autoignition temperature of the organic HAP, the flow rate of the 
organic HAP emission stream, the combustion temperature, and the 
residence time at the combustion temperature.
    (D) For carbon adsorbers, the design evaluation shall include the 
affinity of the organic HAP vapors for carbon, the amount of carbon in 
each bed, the number of beds, the humidity of the feed gases, the 
temperature of the feed gases, the flow rate of the organic HAP 
emission stream, the desorption schedule, the regeneration stream 
pressure or temperature, and the flow rate of the regeneration stream. 
For vacuum desorption, pressure drop shall be included.
    (E) For condensers, the design evaluation shall include the final 
temperature of the organic HAP vapors, the type of condenser, and the 
design flow rate of the organic HAP emission stream.
    (ii) If the control device used to comply with Sec.  63.119(e) is 
also used to comply with Sec.  63.113(a)(2), Sec.  63.126(b)(1), or 
Sec.  63.139(c), the performance test required by Sec.  63.116(c), 
Sec.  63.128(a), or Sec.  63.139(d)(1) is acceptable to demonstrate 
compliance with Sec.  63.119(e). The owner or operator is not required 
to prepare a design evaluation for the control device as described in 
paragraph (d)(1)(i) of this section, if the performance tests meets the 
criteria specified in paragraphs (d)(1)(ii)(A) and (B) of this section.
    (A) The performance test demonstrates that the control device 
achieves greater than or equal to the required control efficiency 
specified in Sec.  63.119 (e)(1) or (2), as applicable; and
    (B) The performance test is submitted as part of the Notification 
of Compliance Status required by Sec.  63.151(b). If the performance 
test report is submitted electronically through the EPA's CEDRI in 
accordance with Sec.  63.152(h), the process unit(s) tested, the 
pollutant(s) tested, and the date that such performance test was 
conducted may be submitted in the notification of compliance status 
report in lieu of the performance test results. The performance test 
results must be submitted to CEDRI by the date the notification of 
compliance status report is submitted.
    (iii) For each source as defined in Sec.  63.101, beginning no 
later than the compliance dates specified in Sec.  63.100(k)(10), if 
the owner or operator vents emissions through a closed vent system to 
an adsorber(s) that cannot be regenerated or a regenerative adsorber(s) 
that is regenerated offsite, then the owner or operator must install a 
system of two or more adsorber units in series and comply with the 
requirements specified in paragraphs (d)(1)(iii)(A) through (C) of this 
section.
    (A) Conduct an initial performance test or design evaluation of the 
adsorber and establish the breakthrough limit and adsorber bed life.
    (B) Monitor the HAP or total organic compound (TOC) concentration 
through a sample port at the outlet of the first adsorber bed in series 
according to the schedule in paragraph (d)(1)(iii)(C)(2) of this 
section. The owner or operator must measure the concentration of HAP or 
TOC using either a portable analyzer, in accordance with Method 21 of 
appendix A-7 to part 60 of this chapter using methane, propane, 
isobutylene, or the primary HAP being controlled as the calibration gas 
or Method 25A of appendix A-7 to part 60 using methane, propane, or the 
primary HAP being controlled as the calibration gas.
    (C) Comply with paragraph (d)(1)(iii)(C)(1) of this section and 
comply with the monitoring frequency according to paragraph 
(d)(1)(iii)(C)(2) of this section.
    (1) The first adsorber in series must be replaced immediately when 
breakthrough, as defined in Sec.  63.101, is detected between the first 
and second adsorber. The original second adsorber (or a fresh canister) 
will become the new first adsorber and a fresh adsorber will become the 
second adsorber. For purposes of this paragraph, ``immediately'' means 
within 8 hours of the detection of a breakthrough for adsorbers of 55 
gallons or less, and within 24 hours of the detection of a breakthrough 
for adsorbers greater than 55 gallons. The owner or operator must 
monitor at the outlet of the first adsorber within 3 days of 
replacement to confirm it is performing properly.
    (2) Based on the adsorber bed life established according to 
paragraph (d)(1)(iii)(A) of this section and the date the adsorbent was 
last replaced, conduct monitoring to detect breakthrough at least 
monthly if the adsorbent has more than 2 months of life remaining, at 
least weekly if the adsorbent has between 2 months and 2 weeks of life 
remaining, and at least daily if the adsorbent has 2 weeks or less of 
life remaining.
    (2) The owner or operator shall submit, as part of the Notification 
of Compliance Status required by Sec.  63.151 (b), a monitoring plan 
containing the information specified in paragraph (d)(2)(i) of this 
section and in either paragraph (d)(2)(ii) or (iii) of this section. 
This paragraph does not apply if the owner or operator complies with 
paragraph (d)(1)(iii) of this section.
    (i) A description of the parameter or parameters to be monitored to 
ensure that the control device is being properly operated and 
maintained, an explanation of the criteria used for

[[Page 43192]]

selection of that parameter (or parameters), and the frequency with 
which monitoring will be performed (e.g., when the liquid level in the 
storage vessel is being raised); and either
    (ii) The documentation specified in paragraph (d)(1)(i) of this 
section, if the owner or operator elects to prepare a design 
evaluation; or
    (iii) The information specified in paragraph (d)(2)(iii) (A) and 
(B) of this section if the owner or operator elects to submit the 
results of a performance test.
    (A) Identification of the storage vessel and control device for 
which the performance test will be submitted, and
    (B) Identification of the emission point(s) that share the control 
device with the storage vessel and for which the performance test will 
be conducted.
    (3) The owner or operator shall submit, as part of the Notification 
of Compliance Status required by Sec.  63.152(b) of this subpart, the 
information specified in paragraphs (d)(3)(i) and, if applicable, 
(d)(3)(ii) of this section. This paragraph does not apply if the owner 
or operator complies with paragraph (d)(1)(iii) of this section.
    (i) The operating range for each monitoring parameter identified in 
the monitoring plan. The specified operating range shall represent the 
conditions for which the control device is being properly operated and 
maintained.
    (ii) Results of the performance test described in paragraph 
(d)(1)(ii) of this section. If the performance test report is submitted 
electronically through the EPA's CEDRI in accordance with Sec.  
63.152(h), the process unit(s) tested, the pollutant(s) tested, and the 
date that such performance test was conducted may be submitted in the 
notification of compliance status report in lieu of the performance 
test results. The performance test results must be submitted to CEDRI 
by the date the notification of compliance status report is submitted.
    (4) The owner or operator shall demonstrate compliance with the 
requirements of Sec. Sec.  63.119(e)(3) and (7) (planned routine 
maintenance of a control device, during which the control device does 
not meet the specifications of Sec.  63.119 (e)(1) or (2), as 
applicable, shall not exceed 240 hours per year) by including in each 
Periodic Report required by Sec.  63.152(c) the information specified 
in Sec.  63.122(g)(1).
    (5) The owner or operator shall monitor the parameters specified in 
the Notification of Compliance Status required in Sec.  63.152(b) or in 
the operating permit and shall operate and maintain the control device 
such that the monitored parameters remain within the ranges specified 
in the Notification of Compliance Status.
    (6) Except as provided in paragraph (d)(7) of this section, each 
closed vent system shall be inspected as specified in Sec.  63.148. The 
initial and annual inspections required by Sec.  63.148(b) shall be 
done during filling of the storage vessel.
    (7) For any fixed roof tank and closed vent system that are 
operated and maintained under negative pressure, the owner or operator 
is not required to comply with the requirements specified in Sec.  
63.148.
    (8) A design evaluation or performance test is not required, if the 
owner or operator uses a combustion device meeting the criteria in 
paragraph (d)(8)(i), (ii), (iii), or (iv) of this section.
    (i) A boiler or process heater with a design heat input capacity of 
44 megawatts or greater.
    (ii) A boiler or process heater burning hazardous waste for which 
the owner or operator:
    (A) Has been issued a final permit under part 270 of this chapter 
and complies with the requirements of part 266, subpart H, of this 
chapter;
    (B) Has certified compliance with the interim status requirements 
of part 266, subpart H, of this chapter;
    (C) Has submitted a Notification of Compliance under Sec.  
63.1207(j) and complies with the requirements of subpart EEE of this 
part; or
    (D) Complies with subpart EEE of this part and will submit a 
Notification of Compliance under Sec.  63.1207(j) by the date the owner 
or operator would have been required to submit the initial performance 
test report for this subpart.
    (iii) A hazardous waste incinerator for which the owner or 
operator:
    (A) Has been issued a final permit under part 270 of this chapter 
and complies with the requirements of part 264, subpart O, of this 
chapter;
    (B) Has certified compliance with the interim status requirements 
of part 265, subpart O, of this chapter;
    (C) Has submitted a Notification of Compliance under Sec.  
63.1207(j) and complies with the requirements subpart EEE of this part; 
or
    (D) Complies with the requirements subpart EEE of this part and 
will submit a Notification of Compliance under Sec.  63.1207(j) by the 
date the owner or operator would have been required to submit the 
initial performance test report for this subpart.
    (iv) A boiler or process heater into which the vent stream is 
introduced with the primary fuel.
    (9) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(11), paragraph 
(d)(1)(i) of this section no longer applies to storage vessels in 
ethylene oxide service, as defined in Sec.  63.101.
    (e) Except as specified in paragraph (a) of Sec.  63.108, to 
demonstrate compliance with Sec.  63.119(e) (storage vessel equipped 
with a closed vent system and control device) using a flare, the owner 
or operator shall comply with the requirements in paragraphs (e)(1) 
through (6) of this section.
* * * * *
    (3) The owner or operator shall demonstrate compliance with the 
requirements of Sec. Sec.  63.119(e)(3) and (7) (planned routine 
maintenance of a flare, during which the flare does not meet the 
specifications of Sec.  63.119(e)(1), shall not exceed 240 hours per 
year) by including in each Periodic Report required by Sec.  63.152(c) 
the information specified in Sec.  63.122(g)(1).
* * * * *
    (g) To demonstrate compliance with the emission limits and work 
practice standards specified in Sec.  63.119(a)(5) for storage vessels 
in ethylene oxide service, owners and operators must meet the 
requirements specified in Sec.  63.124.

0
65. Amend Sec.  63.122 by:
0
a. Revising paragraphs (a)(4) and (c)(2);
0
b. Revising and republishing paragraph (g); and
0
c. Adding paragraph (i).
    The revisions, addition, and republication read as follows:


Sec.  63.122  Storage vessel provisions--reporting.

    (a) * * *
    (4) The owner or operator shall submit Periodic Reports as required 
by Sec.  63.152(c) of this subpart and shall submit as part of the 
Periodic Reports the information specified in paragraphs (d), (e), (f), 
(g), and (i) of this section.
* * * * *
    (c) * * *
    (2) Except as specified in paragraph (a) of Sec.  63.108, if a 
flare is used, the owner or operator shall submit the information 
specified in Sec.  63.120(e)(2)(i), (e)(2)(ii) through (iii).
* * * * *
    (g) An owner or operator who elects to comply with Sec.  63.119(e) 
by installing a closed vent system and control device shall submit, as 
part of the next Periodic Report required by Sec.  63.152(c), the 
information specified in paragraphs (g)(1) through (4) of this section.
    (1) As required by Sec.  63.120(d)(4) and (e)(3), the Periodic 
Report shall include the information specified in paragraphs

[[Page 43193]]

(g)(1)(i) through (iii) of this section for those planned routine 
maintenance operations that would require the control device not to 
meet the requirements of Sec.  63.119 (e)(1) or (2), as applicable.
    (i) A description of the planned routine maintenance that is 
anticipated to be performed for the control device during the next 6 
months. This description shall include the type of maintenance 
necessary, planned frequency of maintenance, and lengths of maintenance 
periods.
    (ii) A description of the planned routine maintenance that was 
performed for the control device during the previous 6 months. This 
description shall include the type of maintenance performed and the 
total number of hours during those 6 months that the control device did 
not meet the requirements of Sec.  63.119 (e)(1) or (2), as applicable, 
due to planned routine maintenance.
    (iii) For each source as defined in Sec.  63.101, beginning no 
later than the compliance dates specified in Sec.  63.100(k)(10), for 
each storage vessel for which planned routine maintenance was performed 
during the previous 6 months, report the identification of the storage 
vessel and the height of the liquid in the storage vessel at the time 
the control device is bypassed to conduct the planned routine 
maintenance and at the time the control device is placed back in 
service after completing the routine maintenance. These reports shall 
include the date and time the liquid height was measured.
    (2) If a control device other than a flare is used, the Periodic 
Report shall describe each occurrence when the monitored parameters 
were outside of the parameter ranges documented in the Notification of 
Compliance Status in accordance with Sec.  63.120(d)(3)(i). The 
description shall include the information specified in paragraphs 
(g)(2)(i) and (ii) of this section.
    (i) Identification of the control device for which the measured 
parameters were outside of the established ranges, the date, and the 
parameter that was outside of the established ranges, and
    (ii) Cause for the measured parameters to be outside of the 
established ranges.
    (3) Except as specified in paragraph (a) of Sec.  63.108, if a 
flare is used, the Periodic Report shall describe each occurrence when 
the flare does not meet the general control device requirements 
specified in Sec.  63.11(b) and shall include the information specified 
in paragraphs (g)(3)(i) and (ii) of this section.
    (i) Identification of the flare which does not meet the general 
requirements specified in Sec.  63.11(b), and
    (ii) Reason the flare did not meet the general requirements 
specified in Sec.  63.11(b).
    (4) For each nonregenerative adsorber and regenerative adsorber 
that is regenerated offsite subject to the requirements in Sec.  
63.120(d)(1)(iii), the owner or operator must report the date of each 
instance when breakthrough, as defined in Sec.  63.101, is detected 
between the first and second adsorber and the adsorber is not replaced 
according to Sec.  63.120(d)(1)(iii)(C)(1) and an identification of the 
adsorber for which breakthrough was detected.
* * * * *
    (i) For pressure vessels subject to the requirements of Sec.  
63.119(a)(7), if you obtain an instrument reading greater than 500 ppmv 
of a leak when monitoring a pressure vessel in accordance with Sec.  
63.119(a)(7)(ii), then the Periodic Report must include an 
identification of the pressure vessel and a copy of the records 
specified in Sec.  63.123(b)(2).

0
66. Amend Sec.  63.123 by adding paragraph (b), revising paragraphs (h) 
and (i)(3)(i), and adding paragraphs (j) and (k) to read as follows:


Sec.  63.123  Storage vessel provisions--recordkeeping.

* * * * *
    (b) Each owner or operator of a pressure vessel subject to the 
requirements of Sec.  63.119(a)(7) shall keep readily accessible 
records as specified in paragraphs (b)(1) and (2) of this section.
    (1) The date of each performance test conducted according to Sec.  
63.119(a)(7)(ii).
    (2) The record of each performance test conducted according to 
Sec.  63.119(a)(7)(ii), including the following:
    (i) Date each defect was detected and the instrument reading (in 
ppmv) during the performance test.
    (ii) Date of the next performance test that shows the instrument 
reading is less than 500 ppmv and the instrument reading (in ppmv) 
during the performance test.
    (iii) Start and end dates of each period after the date in 
paragraph (b)(2)(i) of this section when the pressure vessel was 
completely empty.
    (iv) Estimated emissions from each defect.
* * * * *
    (h) An owner or operator who uses the bypass provisions of Sec.  
63.119(f)(3) shall keep in a readily accessible location the records 
specified in paragraphs (h)(1) through (3) of this section.
    (1) The reason it was necessary to bypass the process equipment or 
fuel gas system;
    (2) The duration of the period when the process equipment or fuel 
gas system was bypassed;
    (3) Documentation or certification of compliance with the 
applicable provisions of Sec.  63.119(f)(3)(i) through (iv).
    (i) * * *
    (3) * * *
    (i) A record of the equipment to be used and the procedures to be 
followed when reloading the railcar, tank truck, or barge and 
displacing vapors to the storage vessel from which the liquid 
originates.
* * * * *
    (j) For each nonregenerative adsorber and regenerative adsorber 
that is regenerated offsite subject to the requirements in Sec.  
63.120(d)(1)(iii), the owner or operator must keep the applicable 
records specified in (j)(1) through (3) of this section.
    (1) Breakthrough limit and bed life established according to Sec.  
63.120(d)(1)(iii)(A).
    (2) Each outlet HAP or TOC concentration measured according to 
Sec.  63.120(d)(1)(iii)(B) and (C).
    (3) Date and time you last replaced the adsorbent.
    (k) For storage vessels in ethylene oxide service, subject to the 
requirements of Sec.  63.124, owners and operators must keep the 
records specified in paragraphs (k)(1) and (2) of this section in 
addition to those records specified elsewhere in this section.
    (1) For storage vessels in ethylene oxide service, records of the 
concentration of ethylene oxide of the fluid stored in each storage 
vessel.
    (2) If emissions are vented through a closed-vent system to a non-
flare control device, then the owner or operator must keep records of 
all periods during which operating values are outside of the applicable 
operating limits specified in Sec.  63.124(b)(4) through (6) when 
regulated material is being routed to the non-flare control device. The 
record must specify the operating parameter, the applicable limit, and 
the highest (for maximum operating limits) or lowest (for minimum 
operating limits) value recorded during the period.

0
67. Add Sec.  63.124 to read as follows:


Sec.  63.124  Process vents and storage vessels that are in ethylene 
oxide service--procedures to determine compliance.

    This section applies beginning no later than the compliance dates 
specified in Sec.  63.100(k)(11). In order to demonstrate compliance 
with the emission limits and work practice

[[Page 43194]]

standards specified in Sec.  63.113(j) (for process vents in ethylene 
oxide service) and Sec.  63.119(a)(5) (for storage vessels in ethylene 
oxide service), owners and operators must meet the requirements 
specified in paragraphs (a) and (b) of this section.
    (a) For initial compliance, owners and operators must comply with 
paragraphs (a)(1) through (4) of this section, as applicable.
    (1) If an owner or operator chooses to reduce emissions of ethylene 
oxide by venting emissions through a closed vent system to a flare as 
specified in Sec.  63.113(j)(1) or Sec.  63.119(a)(5)(i), then the 
owner or operator must comply with Sec.  63.148 and conduct the initial 
visible emissions demonstration required by Sec.  63.670(h) as 
specified in Sec.  63.108.
    (2) If an owner or operator chooses to reduce emissions of ethylene 
oxide by venting emissions through a closed vent system to a non-flare 
control device that reduces ethylene oxide by greater than or equal to 
99.9 percent by weight as specified in Sec.  63.113(j)(2) or Sec.  
63.119(a)(5)(ii), then the owner or operator must comply with Sec.  
63.148 and paragraphs (a)(2)(i) through (viii) of this section.
    (i) Conduct an initial performance test of the control device that 
is used to comply with the percent reduction requirement at the inlet 
and outlet of the control device. For purposes of compliance with this 
paragraph, owners and operators may not use a design evaluation. This 
paragraph does not apply if the conditions specified in paragraphs 
(a)(2)(i)(A) through (D) of this section are met for a previously 
conducted measurement or performance test.
    (A) No changes have been made to the process since the time of the 
measurement or performance test;
    (B) The operating conditions and test methods used during 
measurement or performance test conform to the ethylene oxide related 
requirements of this subpart;
    (C) The control device and process parameter values established 
during the previously conducted measurement or performance test are 
used to demonstrate continuous compliance with the ethylene oxide 
related requirements of this subpart; and
    (D) The previously conducted measurement or performance test was 
completed within the last 60 months.
    (ii) Conduct the performance test according to the procedures in 
Sec.  63.116(c). Except as specified in Sec.  63.109(a)(6), use Method 
18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix 
A to this part to determine the ethylene oxide concentration. Use 
Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the 
sampling sites at each sampling location. Determine the gas volumetric 
flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 to part 60 of 
this chapter. Use Method 4 of appendix A-3 to part 60 of this chapter 
convert the volumetric flowrate to a dry basis.
    (iii) Calculate the mass emission rate of ethylene oxide entering 
the control device and exiting the control device using equations 1 and 
2 to this paragraph.
Equations 1 and 2 to Paragraph (a)(2)(iii)
E,inlet = K C,inlet M Qinlet (Eq. 1)
E,outlet = K C,outlet M Qoutlet (Eq. 
2)

Where:

E,inlet, E,outlet = Mass rate of ethylene 
oxide at the inlet and outlet of the control device, respectively, 
kilogram per hour.
C,inlet, C,outlet = Concentration of ethylene 
oxide in the gas stream at the inlet and outlet of the control 
device, respectively, dry basis, parts per million by volume.
M = Molecular weight of ethylene oxide, 44.05 grams per gram-mole.
Qinlet, Qoutlet = Flow rate of the gas stream 
at the inlet and outlet of the control device, respectively, dry 
standard cubic meter per minute.
K = Constant, 2.494 x 10-6 (parts per million)-1 (gram-mole per 
standard cubic meter) (kilogram per gram) (minutes per hour), where 
standard temperature (gram-mole per standard cubic meter) is 20 
[deg]C.

    (iv) Calculate the percent reduction from the control device using 
equation 3 to this paragraph. An owner or operator has demonstrated 
initial compliance with Sec.  63.113(j)(2) or Sec.  63.119(a)(5)(ii) if 
the overall reduction of ethylene oxide is greater than or equal to 
99.9 percent by weight.
Equation 3 to Paragraph (a)(2)(iv)
Percent reduction = (E,inlet-E,outlet)/
E,inlet * 100 (Eq.3)

Where:

E,inlet, E,outlet = Mass rate of ethylene 
oxide at the inlet and outlet of the control device, respectively, 
kilogram per hour, calculated using Equations 1 and 2 to paragraph 
(a)(2)(iii) of this section.

    (v) If a new control device is installed, then conduct a 
performance test of the new device following the procedures in 
paragraphs (a)(2)(i) through (iv) of this section.
    (vi) If an owner or operator vents emissions through a closed vent 
system to a scrubber with a reactant tank, then the owner or operator 
must establish operating parameter limits by monitoring the operating 
parameters specified in paragraphs (a)(2)(vi)(A) through (C) of this 
section during the performance test.
    (A) Scrubber liquid-to-gas ratio (L/G), determined from the total 
scrubber liquid inlet flow rate and the inlet or exit gas flow rate. 
Determine the average L/G during the performance test as the average of 
the test run averages. Alternatively, separately monitor the total 
scrubber liquid flow rate and gas flow rate through the scrubber. 
Determine the average total scrubber liquid flow rate and gas flow 
through the scrubber as the average of the test run averages.
    (B) Scrubber liquid pH of the liquid in the reactant tank. The pH 
may be measured at any point between the discharge from the scrubber 
column and the inlet to the reactant tank. Determine the average pH 
during the performance test as the average of the test run averages.
    (C) Temperature of the scrubber liquid entering the scrubber 
column. The temperature may be measured at any point after the heat 
exchanger and prior to entering the top of the scrubber column. 
Determine the average inlet scrubber liquid temperature as the average 
of the test run averages.
    (vii) If an owner or operator vents emissions through a closed vent 
system to a thermal oxidizer, then the owner or operator must establish 
operating parameter limits by monitoring the operating parameters 
specified in paragraphs (a)(2)(vii)(A) and (B) of this section during 
the performance test.
    (A) Combustion chamber temperature. Determine the average 
combustion chamber temperature during the performance test as the 
average of the test run averages.
    (B) Flue gas flow rate. Determine the average flue gas flow rate 
during the performance test as the average of the test run averages.
    (viii) If an owner or operator vents emissions through a closed 
vent system to a control device other than a flare, scrubber with a 
reactant tank, or thermal oxidizer, then the owner or operator must 
notify the Administrator of the operating parameters that are planned 
to be monitored during the performance test prior to establishing 
operating parameter limits for the control device.
    (3) If an owner or operator chooses to reduce emissions of ethylene 
oxide by venting emissions through a closed vent system to a non-flare 
control device that reduces ethylene oxide to less than 1 ppmv as 
specified in Sec.  63.113(j)(2) or Sec.  63.119(a)(5)(ii), then the 
owner or operator must comply with Sec.  63.148 and either paragraph 
(a)(3)(i) or (ii) of this section.
    (i) Install a continuous emissions monitoring system (CEMS) to 
continuously monitor the ethylene

[[Page 43195]]

oxide concentration at the exit of the control device. The CEMS must 
meet the requirements of either paragraph (a)(3)(i)(A) or (B) of this 
section. Comply with the requirements specified in Sec.  63.2450(j) for 
CEMS.
    (A) An FTIR CEMS meeting the requirements of Performance 
Specification 15 of appendix B to part 60 of this chapter.
    (B) A gas chromatographic CEMS meeting the requirements of 
Performance Specification 9 of appendix B to part 60 of this chapter.
    (ii) If the owner or operator does not install a CEMS under 
paragraph (a)(3)(i) of this section, then the owner or operator must 
comply with paragraphs (a)(3)(ii)(A) through (C) of this section.
    (A) Conduct an initial performance test at the outlet of the 
control device that is used to comply with the concentration 
requirement.
    (B) Conduct the performance test according to the procedures in 
Sec.  63.116(c). Except as specified in Sec.  63.109(a)(6), use Method 
18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix 
A to this part to determine the ethylene oxide concentration. If the 
non-flare control device is a combustion device, correct the ethylene 
oxide concentration to 3 percent oxygen according to Sec.  
63.116(c)(iii)(B), except ``TOC or organic HAP'' and ``TOC (minus 
methane and ethane) or organic HAP'' in the Variables Cc and 
Cm must be replaced with ``ethylene oxide''. An owner or 
operator has demonstrated initial compliance with Sec.  63.113(j)(2) or 
Sec.  63.119(a)(5)(ii), if the ethylene oxide concentration is less 
than 1 ppmv.
    (C) Comply with the requirements specified in paragraphs (a)(2)(v) 
through (viii) of this section, as applicable.
    (4) If owners and operators choose to reduce emissions of ethylene 
oxide by venting emissions through a closed vent system to a non-flare 
control device that reduces ethylene oxide to less than 5 pounds per 
year for all combined process vents within the process as specified in 
Sec.  63.113(j)(2), then the owner or operator must comply with Sec.  
63.148 and paragraphs (a)(4)(i) through (iv) of this section.
    (i) Conduct an initial performance test of the control device that 
is used to comply with the mass emission limit requirement at the 
outlet of the control device.
    (ii) Conduct the performance test according to the procedures in 
Sec.  63.116(c). Except as specified in Sec.  63.109(a)(6), use Method 
18 of appendix A-6 to part 60 of this chapter or Method 320 of appendix 
A to this part to determine the ethylene oxide concentration. Use 
Method 1 or 1A of appendix A-1 to part 60 of this chapter to select the 
sampling site. Determine the gas volumetric flowrate using Method 2, 
2A, 2C, or 2D of 40 CFR part 60, appendix A-2. Use Method 4 of appendix 
A-3 to part 60 of this chapter to convert the volumetric flowrate to a 
dry basis.
    (iii) Calculate the mass emission rate of ethylene oxide exiting 
the control device using Equation 2 to paragraph (a)(2)(iii) of this 
section. An owner or operator has demonstrated initial compliance with 
Sec.  63.113(j)(2) if the ethylene oxide from all process vents 
(controlled and uncontrolled) within the process is less than 5 pounds 
per year when combined.
    (iv) Comply with the requirements specified in paragraphs (a)(2)(v) 
through (viii) of this section, as applicable.
    (b) For continuous compliance, owners and operators must comply 
with paragraphs (b)(1) through (6) of this section, as applicable.
    (1) If an owner or operator chooses to reduce emissions of ethylene 
oxide by venting emissions through a closed vent system to a flare as 
specified in Sec.  63.113(j)(1) or Sec.  63.119(a)(5)(i), then the 
owner or operator must comply with Sec. Sec.  63.148 and 63.108.
    (2) If you choose to reduce emissions of ethylene oxide by venting 
emissions through a closed-vent system to a non-flare control device 
that reduces ethylene oxide to less than 1 ppmv as specified in Sec.  
63.113(j)(2) or Sec.  63.119(a)(5)(ii), and you choose to comply with 
paragraph (a)(3)(i) of this section, then continuously monitor the 
ethylene oxide concentration at the exit of the control device using an 
FTIR CEMS meeting the requirements of Performance Specification 15 of 
appendix B to part 60 of this chapter and Sec.  63.2450(j). If an owner 
or operator uses an FTIR CEMS, then the owner or operator does not need 
to conduct the performance testing required in paragraph (b)(3) of this 
section or the operating parameter monitoring required in paragraphs 
(b)(4) through (6) of this section.
    (3) Conduct a performance test no later than 60 months after the 
previous performance test and reestablish operating parameter limits 
following the procedures in paragraph (a)(2) through (4) of this 
section. The Administrator may request a repeat performance test at any 
time. For purposes of compliance with this paragraph, owners and 
operators may not use a design evaluation.
    (4) If an owner or operator vents emissions through a closed vent 
system to a scrubber with a reactant tank, then the owner or operator 
must comply with Sec.  63.148 and meet the operating parameter limits 
specified in paragraphs (b)(4)(i) through (v) of this section.
    (i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the 
average L/G measured during the most recent performance test. Determine 
total scrubber liquid inlet flow rate with a flow sensor with a minimum 
accuracy of at least 5 percent over the normal range of 
flow measured, or 1.9 liters per minute (0.5 gallons per minute), 
whichever is greater. Determine gas flow rate at either the inlet or 
the exit of the scrubber with a flow sensor with a minimum accuracy of 
at least 5 percent over the normal range of flow measured, 
or 280 liters per minute (10 cubic feet per minute), whichever is 
greater. If gas flow rate is determined at the inlet of the scrubber, 
ensure that all gas flow through the scrubber is accounted for at the 
measurement location. Compliance with the minimum L/G operating limit 
must be determined continuously on a 1-hour block basis. Alternatively, 
minimum total scrubber liquid flow rate, equal to the average total 
scrubber liquid inlet flow rate measured during the most recent 
performance test, and maximum gas flow rate through the scrubber, equal 
to the average gas flow rate through the scrubber during the most 
recent performance test. Compliance with the total scrubber liquid flow 
rate and gas flow rate through the scrubber must be determined 
continuously on a 1-hour block basis.
    (ii) Maximum scrubber liquid pH of the liquid in the reactant tank, 
equal to the average pH measured during the most recent performance 
test. Compliance with the pH operating limit must be determined 
continuously on a 1-hour block basis. Use a pH sensor with a minimum 
accuracy of 0.2 pH units.
    (iii) Pressure drop across the scrubber column, within the pressure 
drop range specified by the manufacturer or established based on 
engineering analysis. Compliance with the pressure drop operating limit 
must be determined continuously on a 1-hour block basis. Use pressure 
sensors with a minimum accuracy of 5 percent over the 
normal operating range or 0.12 kilopascals, whichever is greater.
    (iv) Maximum temperature of the scrubber liquid entering the 
scrubber column, equal to the average temperature measured during the 
most recent performance test. Compliance with the inlet scrubber liquid 
temperature operating limit must be determined continuously on a 1-hour 
block basis. Use a temperature sensor

[[Page 43196]]

with a minimum accuracy of 1 percent over the normal range 
of the temperature measured, expressed in degrees Celsius, or 2.8 
degrees Celsius, whichever is greater.
    (v) Liquid feed pressure to the scrubber column within the feed 
pressure range specified by the manufacturer or established based on 
engineering analysis. Compliance with the liquid feed pressure 
operating limit must be determined continuously on a 1-hour block 
basis. Use a pressure sensor with a minimum accuracy of 5 
percent over the normal operating range or 0.12 kilopascals, whichever 
is greater.
    (5) If an owner or operator vents emissions through a closed vent 
system to a thermal oxidizer, then the owner or operator must comply 
with Sec.  63.148, and the owner or operator must meet the operating 
parameter limits specified in paragraphs (b)(5)(i) and (ii) of this 
section and the requirements in paragraph (b)(5)(iii) of this section.
    (i) Minimum combustion chamber temperature, equal to the average 
combustion chamber temperature measured during the most recent 
performance test. Determine combustion chamber temperature with a 
temperature sensor with a minimum accuracy of at least 1 
percent over the normal range of temperature measured, expressed in 
degrees Celsius, or 2.8 degrees Celsius, whichever is greater. 
Compliance with the minimum combustion chamber temperature operating 
limit must be determined continuously on a 1-hour block basis.
    (ii) Maximum flue gas flow rate, equal to the average flue gas flow 
rate measured during the most recent performance test. Determine flue 
gas flow rate with a flow sensor with a minimum accuracy of at least 
5 percent over the normal range of flow measured, or 280 
liters per minute (10 cubic feet per minute), whichever is greater. 
Compliance with the maximum flue gas flow rate operating limit must be 
determined continuously on a 1-hour block basis.
    (iii) The owner or operator must maintain the thermal oxidizer in 
accordance with good combustion practices that ensure proper 
combustion. Good combustion practices include, but are not limited to, 
proper burner maintenance, proper burner alignment, proper fuel to air 
distribution and mixing, routine inspection, and preventative 
maintenance.
    (6) If an owner or operator vents emissions through a closed vent 
system to a control device other than a flare, scrubber with a reactant 
tank, or thermal oxidizer, then the owner or operator must comply with 
Sec.  63.148, and the owner or operator must monitor the operating 
parameters identified in paragraph (a)(2)(viii) of this section and 
meet the established operating parameter limits to ensure continuous 
compliance. The frequency of monitoring and averaging time will be 
determined based upon the information provided to the Administrator.

0
68. Amend Sec.  63.126 by revising paragraphs (b)(1), (b)(2)(i), 
(d)(1)(i) and (ii), (d)(3)(i), (h) and (i) to read as follows:


Sec.  63.126  Transfer operations provisions--reference control 
technology.

* * * * *
    (b) * * *
    (1) Use a control device to reduce emissions of total organic 
hazardous air pollutants by 98 weight-percent or to an exit 
concentration of 20 parts per million by volume. For combustion 
devices, the emission reduction or concentration shall be calculated on 
a dry basis, corrected to 3-percent oxygen. If a boiler or process 
heater is used to comply with the percent reduction requirement, then 
the vent stream shall be introduced into the flame zone of such a 
device. Compliance may be achieved by using any combination of 
combustion, recovery, and/or recapture devices.
    (2) * * *
    (i) Except as specified in Sec.  63.108(a), the flare shall comply 
with the requirements of Sec.  63.11(b).
* * * * *
    (d) * * *
    (1) * * *
    (i) Except as provided in paragraph (d)(1)(ii) of this section, the 
halogen reduction device shall reduce overall emissions of hydrogen 
halides and halogens, as defined in Sec.  63.111, by 99 percent or 
shall reduce the outlet mass emission rate of total hydrogen halides 
and halogens to 0.45 kilograms per hour or less.
    (ii) If a scrubber or other halogen reduction device was installed 
prior to December 31, 1992, the halogen reduction device shall reduce 
overall emissions of hydrogen halides and halogens, as defined in Sec.  
63.111, by 95 percent or shall reduce the outlet mass of total hydrogen 
halides and halogens to less than 0.45 kilograms per hour.
* * * * *
    (3) * * *
    (i) The vent stream concentration of each organic compound 
containing halogen atoms (parts per million by volume by compound) 
shall be determined based on the following procedures:
    (A) Process knowledge that no halogen or hydrogen halides are 
present in the process, or
    (B) Applicable engineering assessment as specified in Sec.  
63.115(d)(1)(iii), or
    (C) Concentration of organic compounds containing halogens measured 
by Method 18 of appendix A to part 60 of this chapter,
    (D) Any other method or data that has been validated according to 
the applicable procedures in Method 301 of appendix A of this part, or
    (E) ASTM D6420-18 (incorporated by reference, see Sec.  
[thinsp]63.14) may also be used in lieu of Method 18 of appendix A-6 to 
part 60 of this chapter, if the target compounds are all known and are 
all listed in section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 
must not be used for methane and ethane; and ASTM D6420-18 may not be 
used as a total VOC method.
* * * * *
    (h) Except as specified in paragraph (h)(1) of this section, the 
owner or operator of a transfer rack subject to the provisions of this 
subpart shall ensure that no pressure-relief device in the transfer 
rack's vapor collection system or in the organic hazardous air 
pollutants loading equipment of each tank truck or railcar shall begin 
to open during loading. Pressure relief devices needed for safety 
purposes are not subject to this paragraph (h).
    (1) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), this 
paragraph (h) does not apply. Instead, pressure relief devices are 
subject to the requirements specified in Sec.  63.165(e).
    (2) [Reserved]
    (i) Each valve in the vent system that would divert the vent stream 
to the atmosphere, either directly or indirectly, shall be secured in a 
non-diverting position using a carseal or a lock-and-key type 
configuration, or shall be equipped with a flow indicator. Except as 
specified in paragraph (i)(1) of this section, equipment such as low 
leg drains, high point bleeds, analyzer vents, open-ended valves or 
lines, and pressure relief devices needed for safety purposes is not 
subject to this paragraph (i).
    (1) For each source as defined in Sec.  63.101, on and after July 
15, 2027, the last sentence in paragraph (i) of this section no longer 
applies. Instead, the exemptions specified in paragraphs (i)(1)(i) and 
(ii) of this section apply.
    (i) Except for pressure relief devices subject to Sec.  
63.165(e)(4) of subpart H of this part, equipment such as low leg

[[Page 43197]]

drains and equipment subject to the requirements of subpart H of this 
part are not subject to this paragraph (i).
    (ii) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in Sec.  60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as Sec.  60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (i).
    (2) [Reserved]

0
69. Amend Sec.  63.127 by:
0
a. Revising paragraphs (a)(2), (a)(4)(ii)(C), and (b)(3);
0
b. Adding paragraph (b)(4); and
0
c. Revising and republishing paragraph (d).
    The revisions, addition, and republication read as follows:


Sec.  63.127  Transfer operations provisions--monitoring requirements.

    (a) * * *
    (2) Where a flare is used, except as specified in Sec.  63.108(a), 
a device (including but not limited to a thermocouple, infrared sensor, 
or an ultra-violet beam sensor) capable of continuously detecting the 
presence of a pilot flame is required.
* * * * *
    (4) * * *
    (ii) * * *
    (C) The owner or operator may prepare and implement a gas stream 
flow determination plan that documents an appropriate method which will 
be used to determine the gas stream flow. The plan shall require 
determination of gas stream flow by a method which will at least 
provide a value for either a representative or the highest gas stream 
flow anticipated in the scrubber during representative operating 
conditions other than start-ups, shutdowns, or malfunctions. The plan 
shall include a description of the methodology to be followed and an 
explanation of how the selected methodology will reliably determine the 
gas stream flow, and a description of the records that will be 
maintained to document the determination of gas stream flow. The owner 
or operator shall maintain the plan as specified in Sec.  63.103(c). 
For each source as defined in Sec.  63.101, on and after July 15, 2027, 
the phrase ``other than start-ups, shutdowns, or malfunctions'' in this 
paragraph no longer applies.
    (b) * * *
    (3) Except as specified in paragraph (b)(4) of this section, where 
a carbon adsorber is used, an integrating regeneration stream flow 
monitoring device having an accuracy of 10 percent or 
better, capable of recording the total regeneration stream mass flow 
for each regeneration cycle; and a carbon bed temperature monitoring 
device, capable of recording the temperature of the carbon bed after 
regeneration and within 15 minutes of completing any cooling cycle 
shall be used.
    (4) Beginning no later than the compliance dates specified in Sec.  
63.100(k)(10), if the owner or operator vents emissions through a 
closed vent system to an adsorber(s) that cannot be regenerated or a 
regenerative adsorber(s) that is regenerated offsite, then the owner or 
operator must install a system of two or more adsorber units in series 
and comply with the requirements specified in paragraphs (b)(4)(i) 
through (iii) of this section.
    (i) Conduct an initial performance test or design evaluation of the 
adsorber and establish the breakthrough limit and adsorber bed life.
    (ii) Monitor the HAP or total organic compound (TOC) concentration 
through a sample port at the outlet of the first adsorber bed in series 
according to the schedule in paragraph (b)(4)(iii)(B) of this section. 
The owner or operator must measure the concentration of HAP or TOC 
using either a portable analyzer, in accordance with Method 21 of 
appendix A-7 to part 60 of this chapter using methane, propane, 
isobutylene, or the primary HAP being controlled as the calibration gas 
or Method 25A of part 60, appendix A-7, using methane, propane, or the 
primary HAP being controlled as the calibration gas.
    (iii) Comply with paragraph (b)(4)(iii)(A) of this section and 
comply with the monitoring frequency according to paragraph 
(b)(4)(iii)(B) of this section.
    (A) The first adsorber in series must be replaced immediately when 
breakthrough, as defined in Sec.  63.101, is detected between the first 
and second adsorber. The original second adsorber (or a fresh canister) 
will become the new first adsorber and a fresh adsorber will become the 
second adsorber. For purposes of this paragraph, ``immediately'' means 
within 8 hours of the detection of a breakthrough for adsorbers of 55 
gallons or less, and within 24 hours of the detection of a breakthrough 
for adsorbers greater than 55 gallons. The owner or operator must 
monitor at the outlet of the first adsorber within 3 days of 
replacement to confirm it is performing properly.
    (B) Based on the adsorber bed life established according to 
paragraph (b)(4)(i) of this section and the date the adsorbent was last 
replaced, conduct monitoring to detect breakthrough at least monthly if 
the adsorbent has more than 2 months of life remaining, at least weekly 
if the adsorbent has between 2 months and 2 weeks of life remaining, 
and at least daily if the adsorbent has 2 weeks or less of life 
remaining.
* * * * *
    (d) The owner or operator of a Group 1 transfer rack using a closed 
vent system that contains bypass lines that could divert a vent stream 
flow away from the control device used to comply with Sec.  63.126(b) 
shall comply with paragraph (d)(1) or (2) and (d)(3) of this section. 
Except as specified in paragraph (d)(3) of this section, equipment such 
as low leg drains, high point bleeds, analyzer vents, open-ended valves 
or lines, and pressure relief valves needed for safety purposes are not 
subject to this paragraph.
    (1) Properly install, maintain, and operate a flow indicator that 
takes a reading at least once every 15 minutes. Records shall be 
generated as specified in Sec.  63.130(b). The flow indicator shall be 
installed at the entrance to any bypass line that could divert the vent 
stream away from the control device to the atmosphere; or
    (2) Secure the bypass line valve in the closed position with a car-
seal or a lock-and-key type configuration.
    (i) A visual inspection of the seal or closure mechanism shall be 
performed at least once every month to ensure that the valve is 
maintained in the closed position and the vent stream is not diverted 
through the bypass line.
    (ii) If a car-seal has been broken or a valve position changed, the 
owner or operator shall record that the vent stream has been diverted. 
The car-seal or lock-and-key combination shall be returned to the 
secured position as soon as practicable but not later than 15 calendar 
days after the change in position is detected.
    (3) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10):
    (i) The use of a bypass line at any time on a closed vent system to 
divert emissions (subject to the emission standards in Sec.  63.112) to 
the atmosphere or to a control device not meeting the requirements 
specified in this subpart is an emissions standards violation.
    (ii) The last sentence in paragraph (d) of this section no longer 
applies. Instead, the exemptions specified in paragraph (d)(3)(ii)(A) 
and (B) of this section apply.
    (A) Except for pressure relief devices subject to Sec.  
63.165(e)(4), equipment such as low leg drains and equipment subject to 
the requirements of subpart H of this part are not subject to this 
paragraph (d).

[[Page 43198]]

    (B) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in Sec.  60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as Sec.  60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (d).
* * * * *

0
70. Amend Sec.  63.128 by:
0
a. Revising and republishing paragraphs (a)(9) and (10);
0
b. Adding paragraph (a)(12); and
0
c. Revising paragraphs (b) introductory text, (c)(2) and (7), (f)(2), 
and (h)(1)(iv).
    The revisions, addition, and republications read as follows:


Sec.  63.128  Transfer operations provisions--test methods and 
procedures.

    (a) * * *
    (9) For the purpose of determining compliance with the 20 parts per 
million by volume limit in Sec.  63.126(b)(1), Method 18 or Method 25A 
of appendices A-6 and A-7 to part 60 of this chapter, respectively, 
shall be used to measure either organic compound concentration or 
organic HAP concentration, except as provided in paragraphs (a)(11) and 
(12) of this section.
    (i) If Method 25A of appendix A-7 to part 60 of this chapter is 
used, the following procedures shall be used to calculate the 
concentration of organic compounds (CT):
    (A) The principal organic HAP in the vent stream shall be used as 
the calibration gas.
    (B) The span value for Method 25A of appendix A-7 to part 60 of 
this chapter shall be between 1.5 and 2.5 times the concentration being 
measured.
    (C) Use of Method 25A of appendix A-7 to part 60 of this chapter is 
acceptable if the response from the high-level calibration gas is at 
least 20 times the standard deviation of the response from the zero 
calibration gas when the instrument is zeroed on the most sensitive 
scale.
    (D) The concentration of TOC shall be corrected to 3 percent oxygen 
using the procedures and equation in paragraph (a)(9)(v) of this 
section.
    (ii) If Method 18 of appendix A-6 to 40 CFR part 60 is used to 
measure the concentration of organic compounds or ASTM D6420-18 
(incorporated by reference, see Sec.  [thinsp]63.14), the organic 
compound concentration (CT) is the sum of the individual components and 
shall be computed for each run using the following equation:
Equation 1 to Paragraph (a)(9)(ii)
[GRAPHIC] [TIFF OMITTED] TR16MY24.059

Where:

CT = Total concentration of organic compounds (minus 
methane and ethane), dry basis, parts per million by volume.
Cj = Concentration of sample components j, dry basis, 
parts per million by volume.
n = Number of components in the sample.

    (iii) If an owner or operator uses Method 18 of appendix A-6 to 40 
CFR part 60 or ASTM D6420-18 (incorporated by reference, see Sec.  
[thinsp]63.14) to compute total organic HAP concentration rather than 
organic compounds concentration, the equation in paragraph (a)(9)(ii) 
of this section shall be used except that only organic HAP species 
shall be summed. The list of organic HAP's is provided in table 2 to 
subpart F of this part.
    (iv) Method 3A of appendix A-2 to 40 CFR part 60 or the manual 
method in ANSI/ASME PTC 19.10-1981 (incorporated by reference, see 
Sec.  [thinsp]63.14) shall be used to determine the oxygen 
concentration. The sampling site shall be the same as that of the 
organic hazardous air pollutants or organic compound samples, and the 
samples shall be taken during the same time that the organic hazardous 
air pollutants or organic compound samples are taken.
    (v) The organic compound concentration corrected to 3 percent 
oxygen (Cc) shall be calculated using the following equation:
Equation 2 to Paragraph (a)(9)(v)
[GRAPHIC] [TIFF OMITTED] TR16MY24.060

Where:

Cc = Concentration of organic compounds corrected to 3 percent 
oxygen, dry basis, parts per million by volume.
CT = Total concentration of organic compounds, dry basis, 
parts per million by volume.
%O2d = Concentration of oxygen, dry basis, percent by volume.

    (10) For the purpose of determining compliance with the 98-percent 
reduction requirement in Sec.  63.126(b)(1), Method 18 or Method 25A of 
appendices A-6 and A-7 to part 60 of this chapter, respectively, shall 
be used, except as provided in paragraphs (a)(11) and (12) of this 
section.
    (i) For the purpose of determining compliance with the reduction 
efficiency requirement, organic compound concentration may be measured 
in lieu of organic HAP concentration.
    (ii) If Method 25A of appendix A-7 to part 60 of this chapter is 
used to measure the concentration of organic compounds (CT), 
the principal organic HAP in the vent stream shall be used as the 
calibration gas.
    (A) An emission testing interval shall consist of each 15-minute 
period during the performance test. For each interval, a reading from 
each measurement shall be recorded.
    (B) The average organic compound concentration and the volume 
measurement shall correspond to the same emissions testing interval.
    (C) The mass at the inlet and outlet of the control device during 
each testing interval shall be calculated as follows:
Equation 3 to Paragraph (a)(10)(ii)(C)
Mj = FKVs CT

Where:

Mj = Mass of organic compounds emitted during testing interval j, 
kilograms.
Vs = Volume of air-vapor mixture exhausted at standard conditions, 
20 [deg]C and 760 millimeters mercury, standard cubic meters.
CT = Total concentration of organic compounds (as 
measured) at the exhaust vent, parts per million by volume, dry 
basis.
K = Density, kilograms per standard cubic meter organic HAP. 659 
kilograms per standard cubic meter organic HAP. (Note: The density 
term cancels out when the percent reduction is calculated. 
Therefore, the density used has no effect. The density of hexane is 
given so that it can be used to maintain the units of Mj.)
F = 10-6 = Conversion factor, (cubic meters organic HAP 
per cubic meters air) * (parts per million by volume)-1.

    (D) The organic compound mass emission rates at the inlet and 
outlet of the control device shall be calculated as follows:
Equations 4 and 5 to Paragraph (a)(10)(ii)(D)
[GRAPHIC] [TIFF OMITTED] TR16MY24.061

Where:

Ei, Eo = Mass flow rate of organic compounds 
at the inlet (i) and outlet (o) of the combustion or recovery 
device, kilograms per hour.

[[Page 43199]]

Mij, Moj = Mass of organic compounds at the 
inlet (i) or outlet (o) during testing interval j, kilograms.
T = Total time of all testing intervals, hours.
n = Number of testing intervals.

    (iii) If Method 18 of appendix A-6 to 40 CFR part 60 or ASTM D6420-
18 (incorporated by reference, see Sec.  [thinsp]63.14) is used to 
measure organic compounds, the mass rates of organic compounds (Ei, Eo) 
shall be computed using the following equations:
Equations 6 and 7 to Paragraph (a)(10)(iii)
[GRAPHIC] [TIFF OMITTED] TR16MY24.062

Where:

Cij, Coj = Concentration of sample component j 
of the gas stream at the inlet and outlet of the control device, 
respectively, dry basis, parts per million by volume.
MWij, MWoj = Molecular weight of sample 
component j of the gas stream at the inlet and outlet of the control 
device, respectively, gram/gram-mole.
Qi, Qo = Flow rate of gas stream at the inlet 
and outlet of the control device, respectively, dry standard cubic 
meter per minute.
K2 = Constant, 2.494 x 10-6 (parts per 
million)-1 (gram-mole per standard cubic meter) 
(kilogram/gram) (minute/hour), where standard temperature for (gram-
mole per standard cubic meter) is 20 [deg]C.

    (iv) Where Method 18 or 25A of appendices A-6 and A-7 to part 60 of 
this chapter, respectively, or ASTM D6420-18 (incorporated by 
reference, see Sec.  [thinsp]63.14) is used to measure the percent 
reduction in organic compounds, the percent reduction across the 
control device shall be calculated as follows:
Equation 8 to Paragraph (a)(10)(iv)
[GRAPHIC] [TIFF OMITTED] TR16MY24.063

Where:

R = Control efficiency of control device, percent.
Ei = Mass emitted or mass flow rate of organic compounds 
at the inlet to the combustion or recovery device as calculated 
under paragraph (a)(10)(ii)(D) or (a)(10)(iii) of this section, 
kilogram per hour.
Eo = Mass emitted or mass flow rate of organic compounds 
at the outlet of the combustion or recovery device, as calculated 
under paragraph (a)(10)(ii)(D) or (a)(10)(iii) of this section, 
kilogram per hour.
* * * * *
    (12) ASTM D6420-18 (incorporated by reference, see Sec.  
[thinsp]63.14) may also be used in lieu of Method 18 of appendix A-6 to 
part 60 of this chapter, if the target compounds are all known and are 
all listed in section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 
must not be used for methane and ethane; and ASTM D6420-18 may not be 
used as a total VOC method.
    (b) Except as specified in Sec.  63.108(a), when a flare is used to 
comply with Sec.  63.126(b)(2), the owner or operator shall comply with 
paragraphs (b)(1) through (3) of this section. The owner or operator is 
not required to conduct a performance test to determine percent 
emission reduction or outlet organic HAP or TOC concentration.
* * * * *
    (c) * * *
    (2) When a boiler or process heater burning hazardous waste is used 
for which the owner or operator:
    (i) Has been issued a final permit under part 270 of this chapter 
and complies with the requirements of part 266, subpart H, of this 
chapter;
    (ii) Has certified compliance with the interim status requirements 
of part 266, subpart H, of this chapter;
    (iii) Has submitted a Notification of Compliance under Sec.  
63.1207(j) and complies with the requirements of subpart EEE of this 
part; or
    (iv) Complies with subpart EEE of this part and will submit a 
Notification of Compliance under Sec.  63.1207(j) by the date the owner 
or operator would have been required to submit the initial performance 
test report for this subpart.
* * * * *
    (7) When a hazardous waste incinerator is used for which the owner 
or operator:
    (i) Has been issued a final permit under part 270 of this chapter 
and complies with the requirements of part 264, subpart O, of this 
chapter;
    (ii) Has certified compliance with the interim status requirements 
of part 265, subpart O, of this chapter;
    (iii) Has submitted a Notification of Compliance under Sec.  
63.1207(j) and complies with the requirements subpart EEE of this part; 
or
    (iv) Complies with the requirements subpart EEE of this part and 
will submit a Notification of Compliance under Sec.  63.1207(j) by the 
date the owner or operator would have been required to submit the 
initial performance test report for this subpart.
* * * * *
    (f) * * *
    (2) A pressure measurement device which has a precision of 2.5 millimeters of mercury or better and which is capable of 
measuring above the pressure at which the tank truck or railcar is to 
be tested for vapor tightness.
    (h) * * *
    (1) * * *
    (iv) Except as provided in Sec.  63.127(b)(4), for carbon 
adsorbers, the design evaluation shall include the affinity of the 
organic HAP vapors for carbon, the amount of carbon in each bed, the 
number of beds, the humidity of the feed gases, the temperature of the 
feed gases, the flow rate of the organic HAP emission stream, the 
desorption schedule, the regeneration stream pressure or temperature, 
and the flow rate of the regeneration stream. For vacuum desorption, 
pressure drop shall be included.
* * * * *

0
71. Amend Sec.  63.129 by revising paragraphs (a)(2), (a)(5) 
introductory text and (d) to read as follows:


Sec.  63.129  Transfer operations provisions--reporting and 
recordkeeping for performance tests and notification of compliance 
status.

    (a) * * *
    (2) Include the data specified in paragraphs (a)(4) through (a)(7) 
of this section in the Notification of Compliance Status report as 
specified in Sec.  63.152(b) of this subpart. If the performance test 
report is submitted electronically through the EPA's CEDRI in 
accordance with Sec.  63.152(h), the process unit(s) tested, the 
pollutant(s) tested, and the date that such performance test was 
conducted may be submitted in the notification of compliance status 
report in lieu of the performance test results. The performance test 
results must be submitted to CEDRI by the date the notification of 
compliance status report is submitted.
* * * * *
    (5) Except as specified in paragraph (a) of Sec.  63.108, record 
and report the following when using a flare to comply with Sec.  
63.126(b)(2):
* * * * *
    (d) Each owner or operator shall maintain a record describing in 
detail the vent system used to vent each affected transfer vent stream 
to a control device. This document shall list all valves and vent pipes 
that could vent the stream to the atmosphere, thereby bypassing the 
control device; identify which valves are secured by car-seals or lock-
and-key type configurations; and indicate the position (open or closed) 
of those valves which have car-seals.

[[Page 43200]]

Except as specified in paragraph (d)(1) of this section, equipment 
leaks such as low leg drains, high point bleeds, analyzer vents, open-
ended valves or lines, and pressure relief valves needed for safety 
purposes are not subject to this paragraph.
    (1) For each source as defined in Sec.  63.101, on and after July 
15, 2027, the last sentence in paragraph (d) of this section no longer 
applies. Instead, the exemptions specified in paragraph (d)(1)(i) and 
(d)(1)(ii) of this section apply.
    (i) Except for pressure relief devices subject to Sec.  
63.165(e)(4) of subpart H of this part, equipment such as low leg 
drains and equipment subject to the requirements of subpart H of this 
part are not subject to this paragraph (d) of this section.
    (ii) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in 40 CFR 60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as 40 CFR 60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (d) of this section.
    (2) [Reserved]
* * * * *

0
72. Amend Sec.  63.130 by:
0
a. Revising paragraph (a)(1);
0
b. Revising and publishing paragraphs (a)(2) and (b);
0
c. Revising paragraph (c); and
0
d. Revising and republishing paragraph (d).
    The revisions and republications read as follows:


Sec.  63.130  Transfer operations provisions--periodic recordkeeping 
and reporting.

    (a) * * *
    (1) While the transfer vent stream is being vented to the control 
device, continuous records of the equipment operating parameters 
specified to be monitored under Sec.  63.127, and listed in table 7 of 
this subpart or specified by the Administrator in accordance with 
Sec. Sec.  63.127(c) and 63.129(b). For flares complying withSec.  
63.11(b), the hourly records and records of pilot flame outages 
specified in table 7 shall be maintained in place of continuous 
records. For flares complying with Sec.  63.108, the owner or operator 
must comply with the recordkeeping requirements specified therein.
    (2) Records of the daily average value of each monitored parameter 
for each operating day determined according to the procedures specified 
in Sec.  63.152(f), except as provided in paragraphs (a)(2)(i) through 
(a)(2)(iv) of this section.
    (i) For flares, except as specified in paragraph (a) of Sec.  
63.108, records of the times and duration of all periods during which 
the pilot flame is absent shall be kept rather than daily averages.
    (ii) If carbon adsorber regeneration stream flow and carbon bed 
regeneration temperature are monitored, the records specified in table 
7 to this subpart shall be kept instead of the daily averages.
    (iii) Except as specified in paragraph (a)(2)(iv) of this section, 
records of the duration of all periods when the vent stream is diverted 
through bypass lines shall be kept rather than daily averages.
    (iv) For each flow event from a bypass line subject to the 
requirements in Sec.  63.127(d) for each source as defined in Sec.  
63.101, beginning no later than the compliance dates specified in Sec.  
63.100(k)(10), the owner or operator must also maintain records 
sufficient to determine whether or not the detected flow included flow 
requiring control. For each flow event from a bypass line requiring 
control that is released either directly to the atmosphere or to a 
control device not meeting the requirements in this subpart, the owner 
or operator must include an estimate of the volume of gas, the 
concentration of organic HAP in the gas and the resulting emissions of 
organic HAP that bypassed the control device using process knowledge 
and engineering estimates.
* * * * *
    (b) If a vapor collection system containing valves that could 
divert the emission stream away from the control device is used, each 
owner or operator of a Group 1 transfer rack subject to the provisions 
of Sec.  63.127(d) shall keep up-to-date, readily accessible records 
of:
    (1) Hourly records of whether the flow indicator specified under 
Sec.  63.127(d)(1) was operating and whether a diversion was detected 
at any time during the hour, as well as records of the times of all 
periods when the vent stream is diverted from the control device or the 
flow indicator is not operating.
    (2) Where a seal mechanism is used to comply with Sec.  
63.127(d)(2), hourly records of flow are not required. In such cases, 
the owner or operator shall record that the monthly visual inspection 
of the seals or closure mechanisms has been done, and shall record the 
occurrence of all periods when the seal mechanism is broken, the bypass 
line valve position has changed, or the key for a lock-and-key type 
lock has been checked out, and records of any car-seal that has broken, 
as listed in table 7 of this subpart.
    (3) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), the owner 
or operator must comply with this paragraph in addition to the 
requirements in paragraphs (b)(1) and (b)(2) of this section. For each 
flow event from a bypass line subject to the requirements in Sec.  
63.127(d), the owner or operator must maintain records sufficient to 
determine whether or not the detected flow included flow requiring 
control. For each flow event from a bypass line requiring control that 
is released either directly to the atmosphere or to a control device 
not meeting the requirements in this subpart, the owner or operator 
must include an estimate of the volume of gas, the concentration of 
organic HAP in the gas and the resulting emissions of organic HAP that 
bypassed the control device using process knowledge and engineering 
estimates.
    (c) Except as specified in paragraph (a) of Sec.  63.108, each 
owner or operator of a Group 1 transfer rack who uses a flare to comply 
with Sec.  63.126(b)(2) shall keep up-to-date, readily accessible 
records of the flare pilot flame monitoring specified under Sec.  
63.127(a)(2).
    (d) Each owner or operator of a transfer rack subject to the 
requirements of Sec.  63.126 shall submit to the Administrator Periodic 
Reports of the following information according to the schedule in Sec.  
63.152(c):
    (1) Reports of daily average values of monitored parameters for all 
operating days when the daily average values were outside the range 
established in the Notification of Compliance Status or operating 
permit. Additionally, report the identification of the transfer rack, 
the monitored parameter out of range, and the date of such occurrences.
    (2) Reports of the start date and duration (in hours) of periods 
when monitoring data are not collected for each excursion caused by 
insufficient monitoring data as defined in Sec.  63.152(c)(2)(ii)(A).
    (3) Reports of the start date and time and duration (in hours) of 
all periods recorded under paragraph (b)(1) of this section when the 
vent stream was diverted from the control device, and if applicable, 
the information in paragraph (d)(7) of this section.
    (4) Reports of the start date and time and duration (in hours) 
recorded under paragraph (b)(2) of this section when maintenance is 
performed on car-sealed valves, when the car seal is broken, when the 
bypass line valve position is changed, or the key for a lock-and-key 
type configuration has been checked out, and if applicable, the 
information in paragraph (d)(7) of this section.
    (5) Except as specified in paragraph (a) of Sec.  63.108, reports 
of the times and durations of all periods recorded under

[[Page 43201]]

paragraph (a)(2)(i) of this section in which all pilot flames of a 
flare were absent.
    (6) Reports of all carbon bed regeneration cycles during which the 
parameters recorded under paragraph (a)(2)(ii) of this section were 
outside the ranges established in the Notification of Compliance Status 
or operating permit. Include the identification of the carbon bed, the 
monitored parameter that was outside the established range, and the 
start date, start time, and duration (in hours) for the regeneration 
cycle in the report.
    (7) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), the owner 
or operator must comply with this paragraph in addition to the 
requirements in paragraphs (d)(3) and (d)(4) of this section. For 
bypass lines subject to the requirements in Sec.  63.127(d), the 
Periodic Report must include the start date, start time, duration in 
hours, estimate of the volume of gas in standard cubic feet, the 
concentration of organic HAP in the gas in parts per million by volume 
and the resulting mass emissions of organic HAP in pounds that bypass a 
control device. For periods when the flow indicator is not operating, 
report the start date, start time, and duration in hours.
* * * * *

0
73. Amend Sec.  63.132 by:
0
a. Revising paragraphs (a)(2)(i), (b)(3)(i), and (c)(1);
0
b. Revising and republishing paragraph (d);
0
c. Revising paragraph (f)(2); and
0
d. Adding paragraph (f)(5).
    The revisions, addition and republication read as follows:


Sec.  63.132  Process wastewater provisions--general.

    (a) * * *
    (2) * * *
    (i) Comply with the applicable requirements for wastewater tanks, 
surface impoundments, containers, individual drain systems, and oil/
water separators as specified in Sec.  63.133 through Sec.  63.137 of 
this subpart, except as provided in paragraphs (a)(2)(i)(A) through 
(a)(2)(i)(C) of this section and Sec.  63.138(a)(3).
    (A) Except as specified in paragraph (a)(2)(i)(C) of this section, 
the waste management units may be equipped with pressure relief devices 
that vent directly to the atmosphere provided the pressure relief 
device is not used for planned or routine venting of emissions.
    (B) Except as specified in paragraph (a)(2)(i)(C) of this section, 
the pressure relief device remains in a closed position at all times 
except when it is necessary for the pressure relief device to open for 
the purpose of preventing physical damage or permanent deformation of 
the waste management unit in accordance with good engineering and 
safety practices.
    (C) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraphs 
(a)(2)(i)(A) and (a)(2)(i)(B) of this section do not apply. Instead, 
pressure relief devices are subject to the requirements specified in 
Sec.  63.165(e) of subpart H of this part.
* * * * *
    (b) * * *
    (3) * * *
    (i) Comply with the applicable requirements for wastewater tanks, 
surface impoundments, containers, individual drain systems, and oil/
water separators specified in the requirements of Sec.  63.133 through 
Sec.  63.137 of this subpart, except as provided in paragraphs 
(b)(3)(i)(A) through (b)(3)(i)(C) of this section and Sec.  
63.138(a)(3) of this subpart.
    (A) Except as specified in paragraph (b)(3)(i)(C) of this section, 
the waste management units may be equipped with pressure relief devices 
that vent directly to the atmosphere provided the pressure relief 
device is not used for planned or routine venting of emissions.
    (B) Except as specified in paragraph (b)(3)(i)(C) of this section, 
the pressure relief device remains in a closed position at all times 
except when it is necessary for the pressure relief device to open for 
the purpose of preventing physical damage or permanent deformation of 
the waste management unit in accordance with good engineering and 
safety practices.
    (C) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), paragraphs 
(b)(3)(i)(A) and (b)(3)(i)(B) of this section do not apply. Instead, 
pressure relief devices are subject to the requirements specified in 
Sec.  63.165(e).
* * * * *
    (c) * * *
    (1) A wastewater stream is a Group 1 wastewater stream for Table 9 
compounds if:
    (i) The total annual average concentration of Table 9 compounds is 
greater than or equal to 10,000 parts per million by weight at any flow 
rate;
    (ii) The total annual average concentration of Table 9 compounds is 
greater than or equal to 1,000 parts per million by weight and the 
annual average flow rate is greater than or equal to 10 liters per 
minute; or
    (iii) For each source as defined in Sec.  63.101, beginning no 
later than the compliance dates specified in Sec.  63.100(k)(11), the 
process wastewater stream contains ethylene oxide such that it is 
considered to be in ethylene oxide service, as defined in Sec.  63.101.
* * * * *
    (d) How to determine Group 1 or Group 2 status for Table 8 
compounds. This paragraph provides instructions for determining whether 
a wastewater stream is Group 1 or Group 2 for Table 8 compounds. Annual 
average concentration for each Table 8 compound shall be determined 
according to the procedures specified in Sec.  63.144(b). Annual 
average flow rate shall be determined according to the procedures 
specified in Sec.  63.144(c).
    (1) A wastewater stream is a Group 1 wastewater stream for Table 8 
compounds if:
    (i) The annual average flow rate is 0.02 liter per minute or 
greater and the annual average concentration of any individual table 8 
compound is 10 parts per million by weight or greater; or
    (ii) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(11), the process 
wastewater stream contains ethylene oxide such that it is considered to 
be in ethylene oxide service, as defined in Sec.  63.101.
    (2) A wastewater stream is a Group 2 wastewater stream for Table 8 
compounds if it does not meet the criteria specified in paragraph 
(d)(1)(ii) of this section, and the annual average flow rate is less 
than 0.02 liter per minute or the annual average concentration for each 
individual Table 8 compound is less than 10 parts per million by 
weight.
    (3) The owner or operator of a Group 2 wastewater shall re-
determine group status for each Group 2 stream, as necessary, to 
determine whether the stream is Group 1 or Group 2 whenever process 
changes are made that could reasonably be expected to change the stream 
to a Group 1 stream. Examples of process changes include, but are not 
limited to, changes in production capacity, production rate, feedstock 
type, or whenever there is a replacement, removal, or addition of 
recovery or control equipment. For purposes of this paragraph (d)(3), 
process changes do not include: Process upsets; unintentional, 
temporary process changes; and changes that are within the range on 
which the original determination was based.
* * * * *
    (f) * * *
    (2) Except as specified in paragraph (f)(5) of this sections, 
activities included

[[Page 43202]]

in maintenance or startup/shutdown/malfunction plans;
* * * * *
    (5) For each source as defined in Sec.  63.101, on and after July 
15, 2027, the phrase ``or startup/shutdown/malfunction'' in paragraph 
(f)(2) of this section does not apply.
* * * * *

0
74. Amend Sec.  63.133 by revising paragraphs (a)(2)(i), (b) 
introductory text, (b)(3) and (b)(4) to read as follows:


Sec.  63.133  Process wastewater provisions--wastewater tanks.

    (a) * * *
    (2) * * *
    (i) A fixed roof and a closed vent system that routes the organic 
hazardous air pollutants vapors vented from the wastewater tank to a 
control device.
* * * * *
    (b) If the owner or operator elects to comply with the requirements 
of paragraph (a)(2)(i) of this section, the fixed roof shall meet the 
requirements of paragraph (b)(1) of this section, the control device 
shall meet the requirements of paragraph (b)(2) of this section, and 
the closed vent system shall meet the requirements of paragraph (b)(3) 
of this section.
* * * * *
    (3) Except as provided in paragraph (b)(4) of this section, the 
closed vent system shall be inspected in accordance with the 
requirements of Sec.  63.148.
    (4) For any fixed roof tank and closed vent system that is operated 
and maintained under negative pressure, the owner or operator is not 
required to comply with the requirements specified in Sec.  63.148.
* * * * *

0
75. Amend Sec.  63.134 by revising paragraphs (b) introductory text, 
(b)(4) and (b)(5) to read as follows:


Sec.  63.134  Process wastewater provisions--surface impoundments.

* * * * *
    (b) The owner or operator shall operate and maintain on each 
surface impoundment either a cover (e.g., air-supported structure or 
rigid cover) and a closed vent system that routes the organic hazardous 
air pollutants vapors vented from the surface impoundment to a control 
device in accordance with paragraph (b)(1) of this section, or a 
floating flexible membrane cover as specified in paragraph (b)(2) of 
this section.
* * * * *
    (4) Except as provided in paragraph (b)(5) of this section, the 
closed vent system shall be inspected in accordance with Sec.  63.148.
    (5) For any cover and closed vent system that is operated and 
maintained under negative pressure, the owner or operator is not 
required to comply with the requirements specified in Sec.  63.148.
* * * * *

0
76. Amend Sec.  63.135 by revising paragraph (b)(3), adding paragraph 
(b)(4), and revising paragraphs (d) introductory text, (d)(3) and 
(d)(4) to read as follows:


Sec.  63.135  Process wastewater provisions--containers.

* * * * *
    (b) * * *
    (3) Except as specified in paragraph (b)(4) of this section, the 
cover and all openings shall be maintained in a closed position (e.g., 
covered by a lid) at all times that a Group 1 wastewater stream or 
residual removed from a Group 1 wastewater stream is in the container 
except when it is necessary to use the opening for filling, removal, 
inspection, sampling, or pressure relief events related to safety 
considerations.
    (4) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), pressure 
relief devices are subject to the requirements specified in Sec.  
63.165(e) of subpart H of this part.
* * * * *
    (d) During treatment of a Group 1 wastewater stream or residual 
removed from a Group 1 wastewater stream, including aeration, thermal 
or other treatment, in a container, whenever it is necessary for the 
container to be open, the container shall be located within an 
enclosure with a closed vent system that routes the organic hazardous 
air pollutants vapors vented from the container to a control device.
* * * * *
    (3) Except as provided in paragraph (d)(4) of this section, the 
closed vent system shall be inspected in accordance with Sec.  63.148 
of this subpart.
    (4) For any enclosure and closed vent system that is operated and 
maintained under negative pressure, the owner or operator is not 
required to comply with the requirements specified in Sec.  63.148 of 
this subpart.
* * * * *

0
77. Amend Sec.  63.136 by revising paragraphs (b)(3) and (4) to read as 
follows:


Sec.  63.136  Process wastewater provisions--individual drain systems.

* * * * *
    (b) * * *
    (3) Except as provided in paragraph (b)(4) of this section, the 
closed vent system shall be inspected in accordance with Sec.  63.148.
    (4) For any cover and closed vent system that is operated and 
maintained under negative pressure, the owner or operator is not 
required to comply with the requirements specified in Sec.  63.148.
* * * * *

0
78. Amend Sec.  63.137 by revising paragraphs (a)(1), (b) introductory 
text, (b)(3) and (4) to read as follows:


Sec.  63.137  Process wastewater provisions--oil-water separators.

    (a) * * *
    (1) A fixed roof and a closed vent system that routes the organic 
hazardous air pollutants vapors vented from the oil-water separator to 
a control device. The fixed roof, closed vent system, and control 
device shall meet the requirements specified in paragraph (b) of this 
section;
* * * * *
    (b) If the owner or operator elects to comply with the requirements 
of paragraphs (a)(1) or (a)(2) of this section, the fixed roof shall 
meet the requirements of paragraph (b)(1) of this section, the control 
device shall meet the requirements of paragraph (b)(2) of this section, 
and the closed vent system shall meet the requirements of paragraph 
(b)(3) of this section.
* * * * *
    (3) Except as provided in paragraph (b)(4) of this section, the 
closed vent system shall be inspected in accordance with the 
requirements of Sec.  63.148.
    (4) For any fixed roof and closed vent system that is operated and 
maintained under negative pressure, the owner or operator is not 
required to comply with the requirements of Sec.  63.148.
* * * * *

0
79. Amend Sec.  63.138 by:
0
a. Revising paragraph (b) introductory text and adding paragraph 
(b)(3);
0
b. Revising paragraph (c) introductory text and adding paragraph 
(c)(3); and
0
c. Revising paragraphs (h)(1) and (2).
    The revisions and additions read as follows:


Sec.  63.138  Process wastewater provisions--performance standards for 
treatment processes managing Group 1 wastewater streams and/or 
residuals removed from Group 1 wastewater streams.

* * * * *
    (b) Control options: Group 1 wastewater streams for Table 9 
compounds. The owner or operator shall comply with either paragraph 
(b)(1) or (b)(2) of this section, and paragraph (b)(3) of this section, 
if applicable, for the control of Table 9 compounds at new or existing 
sources.
* * * * *

[[Page 43203]]

    (3) 1 ppmw ethylene oxide concentration. Reduce, by removal or 
destruction, the concentration of ethylene oxide to a level less than 1 
parts per million by weight as determined in the procedures specified 
in Sec.  63.145(b) of this subpart.
    (c) Control options: Group 1 wastewater streams for Table 8 
compounds. The owner or operator shall comply with either paragraph 
(c)(1) or (c)(2) of this section, and paragraph (c)(3) of this section, 
if applicable, for the control of Table 8 compounds at new sources.
* * * * *
    (3) 1 ppmw ethylene oxide concentration. Reduce, by removal or 
destruction, the concentration of ethylene oxide to a level less than 1 
parts per million by weight as determined in the procedures specified 
in Sec.  63.145(b).
* * * * *
    (h) * * *
    (1) The wastewater stream or residual is discharged to a hazardous 
waste incinerator for which the owner or operator:
    (i) Has been issued a final permit under 40 CFR part 270 and 
complies with the requirements of 40 CFR part 264, subpart O;
    (ii) Has certified compliance with the interim status requirements 
of 40 CFR part 265, subpart O;
    (iii) Has submitted a Notification of Compliance under Sec.  
63.1207(j) and complies with the requirements subpart EEE of this part; 
or
    (iv) Complies with the requirements subpart EEE of this part and 
will submit a Notification of Compliance under Sec.  63.1207(j) by the 
date the owner or operator would have been required to submit the 
initial performance test report for this subpart.
    (2) The wastewater stream or residual is discharged to a process 
heater or boiler burning hazardous waste for which the owner or 
operator:
    (i) Has been issued a final permit under 40 CFR part 270 and 
complies with the requirements of 40 CFR part 266, subpart H;
    (ii) Has certified compliance with the interim status requirements 
of 40 CFR part 266, subpart H;
    (iii) Has submitted a Notification of Compliance under Sec.  
63.1207(j) and complies with the requirements of subpart EEE of this 
part; or
    (iv) Complies with subpart EEE of this part and will submit a 
Notification of Compliance under Sec.  63.1207(j) by the date the owner 
or operator would have been required to submit the initial performance 
test report for this subpart.
* * * * *

0
80. Amend Sec.  63.139 by revising paragraphs (c) and (d) to read as 
follows:


Sec.  63.139  Process wastewater provisions--control devices.

* * * * *
    (c) The control device shall be designed and operated in accordance 
with paragraph (c)(1), (2), (3), (4), or (5) of this section.
    (1) An enclosed combustion device (including but not limited to a 
vapor incinerator, boiler, or process heater) shall meet the conditions 
in paragraph (c)(1)(i), (ii), or (iii) of this section, alone or in 
combination with other control devices. If a boiler or process heater 
is used as the control device, then the vent stream shall be introduced 
into the flame zone of the boiler or process heater.
    (i) Reduce the total organic compound emissions, less methane and 
ethane, or total organic hazardous air pollutants emissions vented to 
the control device by 95 percent by weight or greater;
    (ii) Achieve an outlet total organic compound concentration, less 
methane and ethane, or total organic hazardous air pollutants 
concentration of 20 parts per million by volume on a dry basis 
corrected to 3 percent oxygen. The owner or operator shall use either 
Method 18 of appendix A-6 to part 60 of this chapter, any other method 
or data that has been validated according to the applicable procedures 
in Method 301 of appendix A of this part, or ASTM D6420-18 
(incorporated by reference, see Sec.  63.14) may also be used in lieu 
of Method 18, if the target compounds are all known and are all listed 
in Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 must not 
be used for methane and ethane; and ASTM D6420-18 may not be used as a 
total VOC method; or
    (iii) Provide a minimum residence time of 0.5 seconds at a minimum 
temperature of 760 [deg]C.
    (2) A vapor recovery system (including but not limited to a carbon 
adsorption system or condenser), alone or in combination with other 
control devices, shall reduce the total organic compound emissions, 
less methane and ethane, or total organic hazardous air pollutants 
emissions vented to the control device of 95 percent by weight or 
greater or achieve an outlet total organic compound concentration, less 
methane and ethane, or total organic hazardous air pollutants 
concentration of 20 parts per million by volume. The 20 parts per 
million by volume performance standard is not applicable to compliance 
with the provisions of Sec.  63.134 or Sec.  63.135.
    (3) Except as specified in paragraph (a) of Sec.  63.108, a flare 
shall comply with the requirements of Sec.  63.11(b).
    (4) A scrubber, alone or in combination with other control devices, 
shall reduce the total organic compound emissions, less methane and 
ethane, or total organic hazardous air pollutants emissions in such a 
manner that 95 weight-percent is either removed, or destroyed by 
chemical reaction with the scrubbing liquid or achieve an outlet total 
organic compound concentration, less methane and ethane, or total 
organic hazardous air pollutants concentration of 20 parts per million 
by volume. The 20 parts per million by volume performance standard is 
not applicable to compliance with the provisions of Sec.  63.134 or 
Sec.  63.135.
    (5) Any other control device used shall, alone or in combination 
with other control devices, reduce the total organic compound 
emissions, less methane and ethane, or total organic hazardous air 
pollutants emissions vented to the control device by 95 percent by 
weight or greater or achieve an outlet total organic compound 
concentration, less methane and ethane, or total organic hazardous air 
pollutants concentration of 20 parts per million by volume. The 20 
parts per million by volume performance standard is not applicable to 
compliance with the provisions of Sec.  63.134 or Sec.  63.135.
    (d) Except as provided in paragraphs (d)(4) and (5) of this 
section, an owner or operator shall demonstrate that each control 
device or combination of control devices achieves the appropriate 
conditions specified in paragraph (c) of this section by using one or 
more of the methods specified in paragraphs (d)(1), (2), or (3) of this 
section.
    (1) Performance tests conducted using the test methods and 
procedures specified in Sec.  63.145(i) for control devices other than 
flares; or
    (2) A design evaluation that addresses the vent stream 
characteristics and control device operating parameters specified in 
paragraphs (d)(2)(i) through (vii) of this section.
    (i) For a thermal vapor incinerator, the design evaluation shall 
consider the vent stream composition, constituent concentrations, and 
flow rate and shall establish the design minimum and average 
temperature in the combustion zone and the combustion zone residence 
time.
    (ii) For a catalytic vapor incinerator, the design evaluation shall 
consider the vent stream composition, constituent concentrations, and 
flow rate and shall establish the design minimum and average 
temperatures across the catalyst bed inlet and outlet.

[[Page 43204]]

    (iii) For a boiler or process heater, the design evaluation shall 
consider the vent stream composition, constituent concentrations, and 
flow rate; shall establish the design minimum and average flame zone 
temperatures and combustion zone residence time; and shall describe the 
method and location where the vent stream is introduced into the flame 
zone.
    (iv) For a condenser, the design evaluation shall consider the vent 
stream composition, constituent concentrations, flow rate, relative 
humidity, and temperature and shall establish the design outlet organic 
compound concentration level, design average temperature of the 
condenser exhaust vent stream, and the design average temperatures of 
the coolant fluid at the condenser inlet and outlet.
    (v) For a carbon adsorption system that regenerates the carbon bed 
directly on-site in the control device such as a fixed-bed adsorber, 
the design evaluation shall consider the vent stream composition, 
constituent concentrations, flow rate, relative humidity, and 
temperature and shall establish the design exhaust vent stream organic 
compound concentration level, adsorption cycle time, number and 
capacity of carbon beds, type and working capacity of activated carbon 
used for carbon beds, design total regeneration stream mass or 
volumetric flow over the period of each complete carbon bed 
regeneration cycle, design carbon bed temperature after regeneration, 
design carbon bed regeneration time, and design service life of carbon.
    (vi) For a carbon adsorption system that does not regenerate the 
carbon bed directly on-site in the control device such as a carbon 
canister, the design evaluation shall consider the vent stream 
composition, constituent concentrations, mass or volumetric flow rate, 
relative humidity, and temperature and shall establish the design 
exhaust vent stream organic compound concentration level, capacity of 
carbon bed, type and working capacity of activated carbon used for 
carbon bed, and design carbon replacement interval based on the total 
carbon working capacity of the control device and source operating 
schedule.
    (vii) For a scrubber, the design evaluation shall consider the vent 
stream composition; constituent concentrations; liquid-to-vapor ratio; 
scrubbing liquid flow rate and concentration; temperature; and the 
reaction kinetics of the constituents with the scrubbing liquid. The 
design evaluation shall establish the design exhaust vent stream 
organic compound concentration level and will include the additional 
information in paragraphs (d)(2)(vii)(A) and (B) of this section for 
trays and a packed column scrubber.
    (A) Type and total number of theoretical and actual trays;
    (B) Type and total surface area of packing for entire column, and 
for individual packed sections if column contains more than one packed 
section.
    (3) For flares, except as specified in paragraph (a) of Sec.  
63.108, the compliance determination specified in Sec.  63.11(b) and 
Sec.  63.145(j) of this subpart.
    (4) An owner or operator using any control device specified in 
paragraphs (d)(4)(i) through (iv) of this section is exempt from the 
requirements in paragraphs (d)(1) through (3) of this section and from 
the requirements in Sec.  63.6(f), and from the requirements of 
paragraph (e) of this section.
    (i) A boiler or process heater with a design heat input capacity of 
44 megawatts or greater.
    (ii) A boiler or process heater into which the emission stream is 
introduced with the primary fuel.
    (iii) A boiler or process heater burning hazardous waste for which 
the owner or operator:
    (A) Has been issued a final permit under part 270 of this chapter 
and complies with the requirements of part 266, subpart H of this 
chapter;
    (B) Has certified compliance with the interim status requirements 
of part 266, subpart H of this chapter;
    (C) Has submitted a Notification of Compliance under Sec.  
63.1207(j) and complies with the requirements of subpart EEE of this 
part; or
    (D) Complies with subpart EEE of this part and will submit a 
Notification of Compliance under Sec.  63.1207(j) by the date the owner 
or operator would have been required to submit the initial performance 
test report for this subpart.
    (iv) A hazardous waste incinerator for which the owner or operator:
    (A) Has been issued a final permit under part 270 of this chapter 
and complies with the requirements of part 264, subpart O of this 
chapter;
    (B) Has certified compliance with the interim status requirements 
of part 265, subpart O of this chapter;
    (C) Has submitted a Notification of Compliance under Sec.  
63.1207(j) and complies with the requirements subpart EEE of this part; 
or
    (D) Complies with the requirements subpart EEE of this part and 
will submit a Notification of Compliance under Sec.  63.1207(j) by the 
date the owner or operator would have been required to submit the 
initial performance test report for this subpart.
    (5) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), if the 
owner or operator vents emissions through a closed vent system to an 
adsorber(s) that cannot be regenerated or a regenerative adsorber(s) 
that is regenerated offsite, then the requirements specified in 
paragraphs (d)(1) and (2) of this section do not apply. Instead, the 
owner or operator must install a system of two or more adsorber units 
in series and comply with the requirements specified in paragraphs 
(d)(5)(i) through (iii) of this section.
    (i) Conduct an initial performance test or design evaluation of the 
adsorber and establish the breakthrough limit and adsorber bed life.
    (ii) Monitor the HAP or total organic compound (TOC) concentration 
through a sample port at the outlet of the first adsorber bed in series 
according to the schedule in paragraph (d)(5)(iii)(B) of this section. 
The owner or operator must measure the concentration of HAP or TOC 
using either a portable analyzer, in accordance with Method 21 of 
appendix A-7 to 40 CFR part 60, using methane, propane, isobutylene, or 
the primary HAP being controlled as the calibration gas or Method 25A 
of appendix A-7 to 40 CFR part 60, using methane, propane, or the 
primary HAP being controlled as the calibration gas.
    (iii) Comply with paragraph (d)(5)(iii)(A) of this section, and 
comply with the monitoring frequency according to paragraph 
(d)(5)(iii)(B) of this section.
    (A) The first adsorber in series must be replaced immediately when 
breakthrough, as defined in Sec.  63.101, is detected between the first 
and second adsorber. The original second adsorber (or a fresh canister) 
will become the new first adsorber and a fresh adsorber will become the 
second adsorber. For purposes of this paragraph, ``immediately'' means 
within 8 hours of the detection of a breakthrough for adsorbers of 55 
gallons or less, and within 24 hours of the detection of a breakthrough 
for adsorbers greater than 55 gallons. The owner or operator must 
monitor at the outlet of the first adsorber within 3 days of 
replacement to confirm it is performing properly.
    (B) Based on the adsorber bed life established according to 
paragraph (d)(5)(i) of this section and the date the adsorbent was last 
replaced, conduct monitoring to detect breakthrough at least monthly if 
the adsorbent has more than 2 months of life remaining, at least weekly 
if the adsorbent has between 2 months and 2 weeks of life remaining, 
and at least daily if the adsorbent has 2 weeks or less of life 
remaining.
* * * * *

[[Page 43205]]


0
81. Amend Sec.  63.143 by revising paragraph (c) to read as follows:


Sec.  63.143  Process wastewater provisions--inspections and monitoring 
of operations.

* * * * *
    (c) If the owner or operator elects to comply with Item 1 in table 
12 to this subpart, the owner or operator shall request approval to 
monitor appropriate parameters that demonstrate proper operation of the 
biological treatment unit. The request shall be submitted according to 
the procedures specified in Sec.  63.151(f), and shall include a 
description of planned reporting and recordkeeping procedures. The 
owner or operator shall include as part of the submittal the basis for 
the selected monitoring frequencies and the methods that will be used. 
The Administrator will specify appropriate reporting and recordkeeping 
requirements as part of the review of the permit application or by 
other appropriate means.
* * * * *

0
82. Amend Sec.  63.144 by adding paragraph (b)(5)(i)(I) to read as 
follows:


Sec.  63.144  Process wastewater provisions--test methods and 
procedures for determining applicability and Group 1/Group 2 
determinations (determining which wastewater streams require control).

* * * * *
    (b) * * *
    (5) * * *
    (i) * * *
    (I) Methods for ethylene oxide. Methods specified in Sec.  
63.109(d) for analysis of ethylene oxide in wastewater.
* * * * *

0
83. Amend Sec.  63.145 by:
0
a. Revising paragraph (a)(3),
0
b. Adding paragraph (a)(10), and
0
c. Revising paragraphs (d)(4), (i) introductory text, (i)(2), 
(i)(6)(i), and (j) introductory text.
    The revisions and additions read as follows:


Sec.  63.145  Process wastewater provisions--test methods and 
procedures to determine compliance.

    (a) * * *
    (3) Representative process unit operating conditions. Except as 
specified in paragraph (a)(10) of this section, compliance shall be 
demonstrated for representative operating conditions. Operations during 
periods of startup, shutdown, or malfunction and periods of 
nonoperation shall not constitute representative conditions. The owner 
or operator shall record the process information that is necessary to 
document operating conditions during the test.
* * * * *
    (10) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), the 
requirement of paragraph (a)(3) of this section no longer applies. 
Instead, owners and operators must comply with the conditions specified 
in Sec.  63.103(b)(3)(ii) of subpart F of this part.
* * * * *
    (d) * * *
    (4) Concentration in vented gas stream exiting the combustion 
treatment process. The concentration of table 8 and/or table 9 
compounds exiting the combustion treatment process in any vented gas 
stream shall be determined as provided in this paragraph. Samples may 
be grab samples or composite samples. Samples shall be taken at 
approximately equally spaced time intervals over a 1-hour period. Each 
1-hour period constitutes a run, and the performance test shall consist 
of a minimum of 3 runs. Concentration measurements shall be determined 
using Method 18 of appendix A-6 to 40 CFR part 60. ASTM D6420-18 
(incorporated by reference, see Sec.  63.14) may also be used in lieu 
of Method 18, if the target compounds are all known and are all listed 
in Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 must not 
be used for methane and ethane; and ASTM D6420-18 may not be used as a 
total VOC method. Alternatively, any other test method validated 
according to the procedures in Method 301 of appendix A to this part 
may be used.
* * * * *
    (i) Performance tests for control devices other than flares. This 
paragraph applies to performance tests that are conducted to 
demonstrate compliance of a control device with the efficiency limits 
specified in Sec.  63.139(c). If complying with the 95-percent 
reduction efficiency requirement, comply with the requirements 
specified in paragraphs (i)(1) through (i)(9) of this section. If 
complying with the 20 ppm by volume requirement, comply with the 
requirements specified in paragraphs (i)(1) through (6) and (9) of this 
section. The 20 ppm by volume limit or 95-percent reduction efficiency 
requirement shall be measured as either total organic hazardous air 
pollutants or as TOC minus methane and ethane. Performance tests must 
be conducted according to the schedule in Sec.  63.103(b)(1) of subpart 
F of this part.
* * * * *
    (2) Concentration in gas stream entering or exiting the control 
device. The concentration of total organic hazardous air pollutants or 
TOC in a gas stream shall be determined as provided in this paragraph. 
Samples may be grab samples or composite samples (i.e., integrated 
samples). Samples shall be taken at approximately equally spaced time 
intervals over a 1-hour period. Each 1-hour period constitutes a run, 
and the performance test shall consist of a minimum of 3 runs. 
Concentration measurements shall be determined using Method 18 of 
appendix A-6 to 40 CFR part 60. ASTM D6420-18 (incorporated by 
reference, see Sec.  63.14) may also be used in lieu of Method 18, if 
the target compounds are all known and are all listed in Section 1.1 of 
ASTM D6420-18 as measurable; ASTM D6420-18 must not be used for methane 
and ethane; and ASTM D6420-18 may not be used as a total VOC method. 
Alternatively, any other test method validated according to the 
procedures in Method 301 of appendix A to this part may be used.
* * * * *
    (6) * * *
    (i) Oxygen concentration. The concentration of TOC or total organic 
hazardous air pollutants shall be corrected to 3 percent oxygen if the 
control device is a combustion device. Method 3A of appendix A-2 to 40 
CFR part 60 or the manual method in ANSI/ASME PTC 19.10-1981 
(incorporated by reference, see Sec.  63.14) shall be used to determine 
the actual oxygen concentration (%02d). The samples shall be taken 
during the same time that the TOC (minus methane or ethane) or total 
organic hazardous air pollutants samples are taken.
* * * * *
    (j) Except as specified in paragraph (a) of Sec.  63.108, when a 
flare is used to comply with Sec.  63.139(c), the owner or operator 
shall comply with paragraphs (j)(1) through (3) of this section. The 
owner or operator is not required to conduct a performance test to 
determine percent emission reduction or outlet organic HAP or TOC 
concentration.
* * * * *

0
84. Amend Sec.  63.146 by revising paragraphs (b)(7)(i) introductory 
text, (b)(7)(ii)(C), (b)(9)(ii), and revising and republishing 
paragraphs (d) and (e) to read as follows:


Sec.  63.146  Process wastewater provisions--reporting.

* * * * *
    (b) * * *
    (7) * * *

[[Page 43206]]

    (i) Except as specified in paragraph (a) of Sec.  63.108, for each 
flare, the owner or operator shall submit the information specified in 
paragraphs (b)(7)(i)(A) through (b)(7)(i)(C) of this section.
* * * * *
    (ii) * * *
    (C) Results of the performance test specified in Sec.  63.139(d)(1) 
of this subpart. Performance test results shall include operating 
ranges of key process and control parameters during the performance 
test; the value of each parameter being monitored in accordance with 
Sec.  63.143 of this subpart; and applicable supporting calculations. 
If the performance test report is submitted electronically through the 
EPA's CEDRI in accordance with Sec.  63.152(h), the process unit(s) 
tested, the pollutant(s) tested, and the date that such performance 
test was conducted may be submitted in the notification of compliance 
status report in lieu of the performance test results. The performance 
test results must be submitted to CEDRI by the date the notification of 
compliance status report is submitted.
* * * * *
    (9) * * *
    (ii) Results of the performance test specified in Sec.  
63.138(j)(2) of this subpart. Performance test results shall include 
operating ranges of key process and control parameters during the 
performance test; the value of each parameter being monitored in 
accordance with Sec.  63.143 of this subpart; and applicable supporting 
calculations. If the performance test report is submitted 
electronically through the EPA's CEDRI in accordance with Sec.  
63.152(h), the process unit(s) tested, the pollutant(s) tested, and the 
date that such performance test was conducted may be submitted in the 
notification of compliance status report in lieu of the performance 
test results. The performance test results must be submitted to CEDRI 
by the date the notification of compliance status report is submitted.
* * * * *
    (d) Except as provided in paragraph (f) of this section, for each 
treatment process used to comply with Sec.  63.138(b)(1), (c)(1), (d), 
(e), (f), or (g), the owner or operator shall submit as part of the 
next Periodic Report required by Sec.  63.152(c) the information 
specified in paragraphs (d)(1), (2), and (3) of this section for the 
monitoring required by Sec.  63.143(b), (c), and (d).
    (1) For Item 1 in table 12, the owner or operator shall submit the 
results of measurements that indicate that the biological treatment 
unit is outside the range established in the Notification of Compliance 
Status or operating permit. Include the identification of the 
biological treatment unit, the parameter that was out of range and the 
date that the parameter is out of range.
    (2) For Item 2 in table 12, the owner or operator shall submit the 
monitoring results for each operating day during which the daily 
average value of a continuously monitored parameter is outside the 
range established in the Notification of Compliance Status or operating 
permit. Include the identification of the treatment process, the 
parameter that was out of range, and the date the parameter was out of 
range.
    (3) For Item 3 in table 12 of this subpart, the owner or operator 
shall submit the monitoring results for each operating day during which 
the daily average value of any monitored parameter approved in 
accordance with Sec.  63.151 (f) was outside the range established in 
the Notification of Compliance Status or operating permit. Include the 
identification of the treatment process, the parameter that was out of 
range, and the date the parameter was out of range.
    (e) Except as provided in paragraph (f) of this section, for each 
control device used to comply with Sec. Sec.  63.133 through 63.139, 
the owner or operator shall submit as part of the next Periodic Report 
required by Sec.  63.152(c) the information specified in either 
paragraph (e)(1) or (e)(2) of this section.
    (1) The information specified in table 20 of this subpart, 
including the date of each occurrence, or
    (2) If the owner or operator elects to comply with Sec.  
63.143(e)(2) of this subpart, i.e., an organic monitoring device 
installed at the outlet of the control device, the owner or operator 
shall submit the date and the monitoring results for each operating day 
during which the daily average concentration level or reading is 
outside the range established in the Notification of Compliance Status 
or operating permit.
* * * * *

0
85. Amend Sec.  63.147 by revising and republishing paragraph (d) to 
read as follows:


Sec.  63.147  Process wastewater provisions--recordkeeping.

* * * * *
    (d) The owner or operator shall keep records of the daily average 
value of each continuously monitored parameter for each operating day 
as specified in Sec.  63.152(f), except as provided in paragraphs 
(d)(1) through (4) of this section.
    (1) For flares, except as specified in paragraph (a) of Sec.  
63.108, records of the times and duration of all periods during which 
the pilot flame is absent shall be kept rather than daily averages.
    (2) Regenerative carbon adsorbers. Except as specified in paragraph 
(d)(4) of this section, for regenerative carbon adsorbers, the owner or 
operator shall keep the records specified in paragraphs (d)(2)(i) and 
(ii) of this section instead of daily averages.
    (i) Records of the total regeneration stream mass flow for each 
carbon bed regeneration cycle.
    (ii) Records of the temperature of the carbon bed after each 
regeneration cycle.
    (3) Non-regenerative carbon adsorbers. Except as specified in 
paragraph (d)(4) of this section, for non-regenerative carbon adsorbers 
using organic monitoring equipment, the owner or operator shall keep 
the records specified in paragraph (d)(3)(i) of this section instead of 
daily averages. For non-regenerative carbon adsorbers replacing the 
carbon adsorption system with fresh carbon at a regular predetermined 
time interval that is less than the carbon replacement interval that is 
determined by the maximum design flow rate and organic concentration in 
the gas stream vented to the carbon adsorption system, the owner or 
operator shall keep the records specified in paragraph (d)(3)(ii) of 
this section instead of daily averages.
    (i)(A) Record of how the monitoring frequency, as specified in 
table 13 of this subpart, was determined.
    (B) Records of when organic compound concentration of adsorber 
exhaust was monitored.
    (C) Records of when the carbon was replaced.
    (ii)(A) Record of how the carbon replacement interval, as specified 
in table 13 of this subpart, was determined.
    (B) Records of when the carbon was replaced.
    (4) For each nonregenerative adsorber and regenerative adsorber 
that is regenerated offsite subject to the requirements in Sec.  
63.139(d)(5), the owner or operator must keep the applicable records 
specified in (d)(4)(i) through (d)(4)(iii) of this section.
    (i) Breakthrough limit and bed life established according to Sec.  
63.139(d)(5)(i).
    (ii) Each outlet HAP or TOC concentration measured according to 
Sec. Sec.  63.139(d)(5)(ii) and (d)(5)(iii).
    (iii) Date and time you last replaced the adsorbent.
* * * * *

0
86. Amend Sec.  63.148 by:

[[Page 43207]]

0
a. Revising paragraphs (a), (b) introductory text, (f) introductory 
text and (f)(3);
0
b. Adding paragraph (f)(4);
0
c. revising paragraph (i)(3) introductory text and adding paragraph 
(i)(3)(iii); and
0
d. Revising paragraphs (j) and (k).
    The revisions and additions read as follows:


Sec.  63.148  Leak inspection provisions.

    (a) Except as provided in paragraph (k) of this section, for each 
vapor collection system, closed vent system, fixed roof, cover, or 
enclosure required to comply with this section, the owner or operator 
shall comply with the requirements of paragraphs (b) through (j) of 
this section.
    (b) Except as provided in paragraphs (g) and (h) of this section, 
each vapor collection system and closed vent system shall be inspected 
according to the procedures and schedule specified in paragraphs (b)(1) 
and (b)(2) of this section and each fixed roof, cover, and enclosure 
shall be inspected according to the procedures and schedule specified 
in paragraph (b)(3) of this section.
* * * * *
    (f) For each vapor collection system or closed vent system that 
contains bypass lines that could divert a vent stream away from the 
control device and to the atmosphere, the owner or operator shall 
comply with the provisions of either paragraph (f)(1) or (f)(2), and 
(f)(4) of this section, except as provided in paragraph (f)(3) of this 
section.
* * * * *
    (3) Except as specified in paragraph (f)(4) of this section, 
equipment such as low leg drains, high point bleeds, analyzer vents, 
open-ended valves or lines, and pressure relief valves needed for 
safety purposes are not subject to this paragraph.
    (4) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10):
    (i) The use of a bypass line at any time on a closed vent system to 
divert emissions (subject to the emission suppression requirements 
specified in Sec. Sec.  63.133 through 63.137) to the atmosphere or to 
a control device not meeting the requirements specified in this subpart 
is an emissions standards violation.
    (ii) Paragraph (f)(3) of this section no longer applies. Instead, 
the exemptions specified in paragraphs (f)(4)(ii)(A) and (f)(4)(ii)(B) 
of this section apply.
    (A) Except for pressure relief devices subject to Sec.  
63.165(e)(4), equipment such as low leg drains and equipment subject to 
the requirements of subpart H of this part are not subject to this 
paragraph (f) of this section.
    (B) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in 40 CFR 60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as 40 CFR 60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (f) of this section.
* * * * *
    (i) * * *
    (3) For each vapor collection system or closed vent system that 
contains bypass lines that could divert a vent stream away from the 
control device and to the atmosphere, the owner or operator shall keep 
a record of the information specified in either paragraph (i)(3)(i) or 
(i)(3)(ii) of this section in addition to the information specified in 
paragraph (i)(3)(iii) of this section.
* * * * *
    (iii) For each source as defined in Sec.  63.101, beginning no 
later than the compliance dates specified in Sec.  63.100(k)(10), the 
owner or operator must comply with this paragraph in addition to the 
requirements in paragraphs (i)(3)(i) or (i)(3)(ii) of this section. For 
each flow event from a bypass line subject to the requirements in 
paragraph (f) of this section, the owner or operator must maintain 
records sufficient to determine whether or not the detected flow 
included flow requiring control. For each flow event from a bypass line 
requiring control that is released either directly to the atmosphere or 
to a control device not meeting the requirements in this subpart, the 
owner or operator must include an estimate of the volume of gas, the 
concentration of organic HAP in the gas and the resulting emissions of 
organic HAP that bypassed the control device using process knowledge 
and engineering estimates.
* * * * *
    (j) The owner or operator shall submit with the reports required by 
Sec.  63.182(b) of subpart H of this part or with the reports required 
by Sec.  63.152(c) of this subpart, the information specified in 
paragraphs (j)(1) through (3) of this section and if applicable, the 
information in paragraph (j)(4) of this section.
    (1) The information specified in paragraph (i)(4) of this section;
    (2) Reports of the times of all periods recorded under paragraph 
(i)(3)(i) of this section when the vent stream is diverted from the 
control device through a bypass line, including the start date, start 
time, and duration in hours; and
    (3) Reports of all periods recorded under paragraph (i)(3)(ii) of 
this section in which the seal mechanism is broken, the bypass line 
valve position has changed, or the key to unlock the bypass line valve 
was checked out. Include the start date, start time, and duration in 
hours for each period.
    (4) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), the owner 
or operator must comply with this paragraph in addition to the 
requirements in paragraphs (j)(1) through (3) of this section. For 
bypass lines subject to the requirements in paragraph (f) of this 
section, the Periodic Report must include the start date, start time, 
duration in hours, estimate of the volume of gas in standard cubic 
feet, the concentration of organic HAP in the gas in parts per million 
by volume and the resulting mass emissions of organic HAP in pounds 
that bypass a control device. For periods when the flow indicator is 
not operating, report the start date, start time, and duration in 
hours.
    (k) If a closed vent system subject to this section is also subject 
to Sec.  63.172, the owner or operator shall comply with the provisions 
of Sec.  63.172 and is exempt from the requirements of this section.

0
87. Amend Sec.  63.150 by revising paragraphs (f)(2), (g)(2)(ii), 
(g)(2)(iii)(B)(2), (m)(1)(ii) and (m)(2)(i) to read as follows:


Sec.  63.150  Emissions averaging provisions.

* * * * *
    (f) * * *
    (2) Periods of start-up, shutdown, and malfunction as described in 
the source's start-up, shutdown, and malfunction plan required by Sec.  
63.6(e)(3). For each source as defined in Sec.  63.101, on and after 
July 15, 2027, this paragraph no longer applies.
* * * * *
    (g) * * *
    (2) * * *
    (ii) The following equation shall be used for each process vent i 
to calculate EPViu:

[[Page 43208]]

[GRAPHIC] [TIFF OMITTED] TR16MY24.087

Where:

EPViu = Uncontrolled process vent emission rate from 
process vent i, megagrams per month.
Q = Vent stream flow rate, dry standard cubic meters per minute, 
measured using Method 2, 2A, 2C, or 2D of part 60, appendix A, as 
appropriate.
h = Monthly hours of operation during which positive flow is present 
in the vent, hours per month.
Cj = Concentration, parts per million by volume, dry basis, of 
organic HAP j as measured by Method 18 of part 60, appendix A, or 
ASTM D6420-18 (incorporated by reference, see Sec.  63.14).
Mj = Molecular weight of organic HAP j, gram per gram-mole.
n = Number of organic HAP's.

    (A) The values of Q, Cj, and Mj shall be 
determined during a performance test conducted under representative 
operating conditions as specified in Sec.  63.103(b)(3). The values of 
Q, Cj, and Mj shall be established in the 
Notification of Compliance Status and must be updated as provided in 
paragraph (g)(2)(ii)(B) of this section.
* * * * *
    (iii) * * *
    (B) * * *
    (2) For determining debits from Group 1 process vents, recovery 
devices shall not be considered control devices and cannot be assigned 
a percent reduction in calculating EPViACTUAL. The sampling 
site for measurement of uncontrolled emissions is after the final 
recovery device. However, as provided in Sec.  63.113(a)(3), except as 
specified in Sec.  63.113(a)(4), a Group 1 process vent may add 
sufficient recovery to raise the TRE index value above 1.0, thereby 
becoming a Group 2 process vent.
* * * * *
    (m) * * *
    (1) * * *
    (ii) Conduct performance tests to determine percent reduction as 
specified in Sec.  63.116 of this subpart;
* * * * *
    (2) * * *
    (i) Except as specified in Sec.  63.113(a)(4), determine, 
consistent with paragraph (g)(2)(i) of this section, the flow rate, 
organic HAP concentration, and TRE index value using the methods 
specified in Sec.  63.115;
* * * * *

0
88. Amend Sec.  63.151 by revising paragraphs (d)(6)(i) and (d)(6)(v) 
as follows:


Sec.  63.151  Initial notification.

* * * * *
    (d) * * *
    (6) * * *
    (i) The values of the parameters used to determine whether the 
emission point is Group 1 or Group 2. Except as specified in Sec.  
63.113(a)(4), where TRE index value is used for process vent group 
determination, the estimated or measured values of the parameters used 
in the TRE equation in Sec.  63.115(d) (flow rate, organic HAP emission 
rate, TOC emission rate, and net heating value) and the resulting TRE 
index value shall be submitted.
* * * * *
    (v) The operating plan required in Sec.  63.122(a)(2) and (b) for 
each storage vessel controlled with a closed vent system with a control 
device other than a flare.
* * * * *

0
89. Amend Sec.  63.152 by:
0
a. Revising paragraph (b)(1)(i);
0
b. Adding paragraphs (b)(7) through (b)(10);
0
c. Revising and republishing paragraph (c);
0
d. Revising paragraphs (d)(1), (f) introductory text and (f)(7) 
introductory text;
0
e. Adding paragraph (f)(7)(vi);
0
f. Revising and republishing paragraphs (g)(1) and (2); and
0
g. Adding paragraph (h) as follows:


Sec.  63.152  General reporting and continuous records.

* * * * *
    (b) * * *
    (1) * * *
    (i) For performance tests and group determinations that are based 
on measurements, the Notification of Compliance Status shall include 
one complete test report for each test method used for a particular 
kind of emission point. For additional tests performed for the same 
kind of emission point using the same method, the results and any other 
information required in Sec.  63.117 for process vents, Sec.  63.129 
for transfer, and Sec.  63.146 for process wastewater shall be 
submitted, but a complete test report is not required. If the 
performance test report is submitted electronically through the EPA's 
CEDRI in accordance with paragraph (h) of this section, the process 
unit(s) tested, the pollutant(s) tested, and the date that such 
performance test was conducted may be submitted in the notification of 
compliance status report in lieu of the performance test results. The 
performance test results must be submitted to CEDRI by the date the 
notification of compliance status report is submitted.
* * * * *
    (7) For flares subject to the requirements in Sec.  63.108, owners 
and operators must also submit the information in this paragraph in a 
supplement to the Notification of Compliance Status within 150 days 
after the first applicable compliance date for flare monitoring. The 
supplement to the Notification of Compliance Status must include flare 
design (e.g., steam-assisted, air-assisted, non-assisted, or pressure-
assisted multi-point); all visible emission readings, heat content 
determinations, flow rate measurements, and exit velocity 
determinations made during the initial visible emissions demonstration 
required by Sec.  63.670(h) of subpart CC of this part, as applicable; 
and all periods during the compliance determination when the pilot 
flame or flare flame is absent.
    (8) For process vents and storage vessels subject to the 
requirements of Sec.  63.124, owners and operators must also submit the 
information in this paragraph in a supplement to the Notification of 
Compliance Status within 150 days after the first applicable compliance 
date. The supplement to the Notification of Compliance Status must 
identify all process vents and storage vessels that are in ethylene 
oxide service as defined in Sec.  63.101, the method(s) used to control 
ethylene oxide emissions from each process vent and storage vessel 
(i.e., use of a flare, scrubber, or other control device) and the 
information specified in paragraphs (b)(8)(i) and (b)(8)(ii) of this 
section, as applicable.
    (i) For process vents, all uncontrolled, undiluted ethylene oxide 
concentration measurements, and the calculations used to determine the 
total uncontrolled ethylene oxide mass emission rate for the sum of all 
vent gas streams; and
    (ii) For storage vessels, include the concentration of ethylene 
oxide of the fluid stored in each storage vessel.
    (9) For adsorbers subject to the requirements of Sec. Sec.  
63.114(a)(5)(v), 63.120(d)(1)(iii), 63.127(b)(4), and 63.139(d)(5), you 
must also submit the information listed in paragraphs (b)(9)(i) and 
(ii) of this section in a supplement

[[Page 43209]]

to the Notification of Compliance Status within 150 days after the 
first applicable compliance date.
    (i) Whether the adsorber cannot be regenerated or is a regenerative 
adsorber(s) that is regenerated offsite.
    (ii) The breakthrough limit and adsorber bed life established 
during the initial performance test or design evaluation of the 
adsorber.
    (10) For Group 2 process vents subject to the requirements in Sec.  
63.113(l), owners and operators must also submit the information in 
this paragraph in a supplement to the Notification of Compliance Status 
within 150 days after the first applicable compliance date. The 
supplement to the Notification of Compliance Status must identify each 
Group 2 process vent and include the data and calculations specified in 
Sec.  63.115(g) that are used to demonstrate that the total organic HAP 
mass flow rate of each vent stream is less than 1.0 pound per hour.
    (c) The owner or operator of a source subject to this subpart shall 
submit Periodic Reports. On and after July 15, 2027 or once the 
reporting template for this subpart has been available on the CEDRI 
website for 1 year, whichever date is later, owners and operators must 
submit all subsequent reports following the procedure specified in 
Sec.  63.9(k), except any medium submitted through mail must be sent to 
the attention of the Hazardous Organic Chemical Manufacturing Sector 
Lead. Owners and operators must use the appropriate electronic report 
template on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for this subpart. The date report 
templates become available will be listed on the CEDRI website. Unless 
the Administrator or delegated state agency or other authority has 
approved a different schedule for submission of reports under Sec.  
63.9(i) and Sec.  63.10(a), the report must be submitted by the 
deadline specified in this subpart, regardless of the method in which 
the report is submitted.
    (1) Except as specified under paragraphs (c)(5) and (c)(6) of this 
section, a report containing the information in paragraphs (c)(2), 
(c)(3), (c)(4), and (c)(7) of this section shall be submitted 
semiannually no later than 60 calendar days after the end of each 6-
month period. The first report shall be submitted no later than 8 
months after the date the Notification of Compliance Status is due and 
shall cover the 6-month period beginning on the date the Notification 
of Compliance Status is due. All periodic reports must contain the 
company name and address (including county), as well as the beginning 
and ending dates of the reporting period.
    (2) Except as provided in paragraph (c)(2)(iv) of this section, for 
an owner or operator of a source complying with the provisions of 
Sec. Sec.  63.113 through 63.147 for any emission points, Periodic 
Reports shall include all information specified in Sec. Sec.  63.117 
and 63.118 for process vents, Sec.  63.122 for storage vessels, 
Sec. Sec.  63.129 and 63.130 for transfer operations, and Sec.  63.146 
for process wastewater, including reports of each excursion (i.e., each 
period when a monitored parameter is outside the established range and 
periods of insufficient monitoring data) using the procedures described 
in paragraphs (c)(2)(i) through (c)(2)(iv) of this section.
    (i) Report the affected sources or equipment, the monitored 
parameter that was exceeded and the date of each excursion.
    (ii) The parameter monitoring data for Group 1 emission points and 
emission points included in emissions averages that are required to 
perform continuous monitoring shall be used to determine compliance 
with the required operating conditions for the monitored control 
devices or recovery devices. For each excursion as specified in 
paragraphs (c)(2)(ii)(A) through (c)(2)(ii)(E) of this section, or 
paragraph (g)(2)(iv) of this section, except for excused excursions 
described therein, the owner or operator shall be deemed to have failed 
to have applied the control in a manner that achieves the required 
operating conditions and must report the information specified in 
paragraph (c)(2)(ii)(F) of this section.
    (A) An excursion means any of the three cases listed in paragraph 
(c)(2)(ii)(A)(1), (c)(2)(ii)(A)(2), or (c)(2)(ii)(A)(3) of this 
section. For a control device or recovery device where multiple 
parameters are monitored, if one or more of the parameters meets the 
excursion criteria in paragraph (c)(2)(ii)(A)(1), (c)(2)(ii)(A)(2), or 
(c)(2)(ii)(A)(3) of this section, this is considered a single excursion 
for the control device or recovery device.
    (1) When the daily average value of one or more monitored 
parameters is outside the permitted range.
    (2) When the period of control device or recovery device operation 
is 4 hours or greater in an operating day and monitoring data are 
insufficient to constitute a valid hour of data for at least 75 percent 
of the operating hours.
    (3) When the period of control device or recovery device operation 
is less than 4 hours in an operating day and more than one of the hours 
during the period of operation does not constitute a valid hour of data 
due to insufficient monitoring data.
    (4) Monitoring data are insufficient to constitute a valid hour of 
data, as used in paragraphs (c)(2)(ii)(A)(2) and (c)(2)(ii)(A)(3) of 
this section, if measured values are unavailable for any of the 15-
minute periods within the hour. For data compression systems approved 
under Sec.  63.151(g)(4), monitoring data are insufficient to calculate 
a valid hour of data if there are less than 4 data values recorded 
during the hour.
    (B) The number of excused excursions for each control device or 
recovery device for each semiannual period is specified in paragraphs 
(c)(2)(ii)(B)(1) through (c)(2)(ii)(B)(6) of this section. This 
paragraph applies to sources required to submit Periodic Reports 
semiannually or quarterly. The first semiannual period is the 6-month 
period starting the date the Notification of Compliance Status is due.
    (1) For the first semiannual period--six excused excursions.
    (2) For the second semiannual period--five excused excursions.
    (3) For the third semiannual period--four excused excursions.
    (4) For the fourth semiannual period--three excused excursions.
    (5) For the fifth semiannual period--two excused excursions.
    (6) For the sixth and all subsequent semiannual periods--one 
excused excursion.
    (C) A monitored parameter that is outside its established range or 
monitoring data that are not collected are excursions. However, if the 
conditions in paragraph (c)(2)(ii)(C)(1) or (c)(2)(ii)(C)(2) of this 
section are met, these excursions are not violations and do not count 
toward the number of excused excursions for determining compliance.
    (1) Periods of startup, shutdown, or malfunction. During periods of 
startup, shutdown, or malfunction when the source is operated during 
such periods in accordance with Sec.  63.102(a)(4). For each source as 
defined in Sec.  63.101, on and after July 15, 2027, this paragraph no 
longer applies.
    (2) Periods of nonoperation. During periods of nonoperation of the 
chemical manufacturing process unit, or portion thereof, that results 
in cessation of the emissions to which the monitoring applies.
    (D) Nothing in paragraph (c)(2)(ii) of this section shall be 
construed to allow or excuse a monitoring parameter excursion caused by 
any activity that violates other applicable provisions of subpart A, F, 
or G of this part.

[[Page 43210]]

    (E) Paragraph (c)(2)(ii) of this section, except paragraph 
(c)(2)(ii)(C) of this section, shall apply only to emission points and 
control devices or recovery devices for which continuous monitoring is 
required by Sec. Sec.  63.113 through 63.150.
    (F) For each source as defined in Sec.  63.101, beginning no later 
than the compliance dates specified in Sec.  63.100(k)(10), for each 
excursion that is not an excused excursion, the report must include a 
list of the affected sources or equipment, the monitored parameter for 
which there was an excursion, the date of the excursion, an estimate of 
the quantity in pounds of each regulated pollutant emitted over any 
emission limit, a description of the method used to estimate the 
emissions, the cause of the excursion (including unknown cause, if 
applicable), as applicable, and the corrective action taken.
    (iii) Periodic Reports shall include the daily average values of 
monitored parameters for both excused and unexcused excursions, as 
defined in paragraph (c)(2)(ii)(A) of this section. For excursions 
caused by lack of monitoring data, the affected equipment or source, 
the monitored parameter, the start date and duration in hours of 
periods when monitoring data were not collected shall be specified.
    (iv) The provisions of paragraphs (c)(2) of this section, and 
(c)(2)(i) through (iii) of this section, do not apply to any storage 
vessel for which the owner or operator is not required, by the 
applicable monitoring plan established under Sec.  63.120(d)(2), to 
keep continuous records. If continuous records are required, the owner 
or operator shall specify, in the monitoring plan, whether the 
provisions of paragraphs (c)(2) of this section, and (c)(2)(i) through 
(iii) of this section apply.
    (3) Except as specified in paragraph (c)(3)(iii) of this section, 
if any performance tests are reported in a Periodic Report, the 
following information shall be included:
    (i) One complete test report shall be submitted for each test 
method used for a particular kind of emission point tested. A complete 
test report shall contain the information specified in paragraph 
(b)(1)(ii) of this section.
    (ii) For additional tests performed for the same kind of emission 
point using the same method, results and any other information required 
in Sec.  63.117 for process vents, Sec.  63.129 for transfer, and Sec.  
63.146 for process wastewater shall be submitted, but a complete test 
report is not required.
    (iii) If the performance test report is submitted electronically 
through the EPA's CEDRI in accordance with paragraph (h) of this 
section, the process unit(s) tested, the pollutant(s) tested, and the 
date that such performance test was conducted may be submitted in the 
Periodic Report in lieu of the performance test results. The 
performance test results must be submitted to CEDRI by the date the 
Periodic Report is submitted.
    (4) Periodic Reports shall include the information in paragraphs 
(c)(4)(i) through (iv) of this section, as applicable:
    (i) For process vents, reports of process changes as required under 
Sec.  63.118(g), (h), (i), and (j),
    (ii) Any supplements required under Sec.  63.151(i) and (j),
    (iii) Notification if any Group 2 emission point becomes a Group 1 
emission point, including a compliance schedule as required in Sec.  
63.100, and
    (iv) For gas streams sent for disposal pursuant to Sec.  63.113(i) 
or for process wastewater streams sent for treatment pursuant to Sec.  
63.132(g), reports of changes in the identity of the transferee.
    (5) The owner or operator of a source shall submit quarterly 
reports for all emission points included in an emissions average.
    (i) The quarterly reports shall be submitted no later than 60 
calendar days after the end of each quarter. The first report shall be 
submitted with the Notification of Compliance Status no later than 5 
months after the compliance date specified in Sec.  63.100.
    (ii) The quarterly reports shall include the information specified 
in this paragraph for all emission points included in an emissions 
average.
    (A) The credits and debits calculated each month during the 
quarter;
    (B) A demonstration that debits calculated for the quarter are not 
more than 1.30 times the credits calculated for the quarter, as 
required under Sec.  63.150(e)(4).
    (C) The values of any inputs to the credit and debit equations in 
Sec.  63.150(g) and (h) that change from month to month during the 
quarter or that have changed since the previous quarter;
    (D) Results of any performance tests conducted during the reporting 
period including one complete report for each test method used for a 
particular kind of emission point as described in paragraph (c)(3) of 
this section. If the performance test report is submitted 
electronically through the EPA's CEDRI in accordance with paragraph (h) 
of this section, the process unit(s) tested, the pollutant(s) tested, 
and the date that such performance test was conducted may be submitted 
in the Periodic Report in lieu of the performance test results. The 
performance test results must be submitted to CEDRI by the date the 
Periodic Report is submitted.;
    (E) Reports of daily average values of monitored parameters for 
both excused and unexcused excursions as defined in paragraph 
(c)(2)(ii)(A) of this section. For excursions caused by lack of 
monitoring data, the duration of periods when monitoring data were not 
collected shall be specified. Include the affected sources or 
equipment, monitored parameter, and the date for each excursion.
    (iii) Paragraphs (c)(2)(i) through (iii) of this section shall 
govern the use of monitoring data to determine compliance for Group 1 
and Group 2 points included in emissions averages. For storage vessels 
to which the provisions of paragraphs (c)(2)(i) through (iii) of this 
section do not apply (as specified in paragraph (c)(2)(iv) of this 
section), the owner or operator is required to comply with the 
provisions of the applicable monitoring plan, and monitoring records 
may be used to determine compliance.
    (iv) Every fourth quarterly report shall include the following:
    (A) A demonstration that annual credits are greater than or equal 
to annual debits as required by Sec.  63.150(e)(3); and
    (B) A certification of compliance with all the emissions averaging 
provisions in Sec.  63.150.
    (6) The owner or operator of a source shall submit reports 
quarterly for particular emission points not included in an emissions 
average under the circumstances described in paragraphs (c)(6)(i) 
through (v) of this section.
    (i) The owner or operator of a source subject to this subpart shall 
submit quarterly reports for a period of one year for an emission point 
that is not included in an emissions average if:
    (A) The emission point has more excursions, as defined in paragraph 
(c)(2)(ii) of this section, than the number of excused excursions 
allowed under paragraph (c)(2)(ii)(B) of this section for a semiannual 
reporting period; and
    (B) The Administrator requests the owner or operator to submit 
quarterly reports for the emission point.
    (ii) The quarterly reports shall include all information in 
paragraphs (c)(2), (3), and (4) of this section applicable to the 
emission point(s) for which quarterly reporting is required under 
paragraph (c)(6)(i) of this section. Information applicable to other 
emission points within the source shall be submitted in the semiannual 
reports required under paragraph (c)(1) of this section.

[[Page 43211]]

    (iii) Quarterly reports shall be submitted no later than 60 
calendar days after the end of each quarter.
    (iv) After quarterly reports have been submitted for an emission 
point for one year, the owner or operator may return to semiannual 
reporting for the emission point unless the Administrator requests the 
owner or operator to continue to submit quarterly reports.
    (v) Paragraphs (c)(2)(i) through (iii) of this section shall govern 
the use of monitoring data to determine compliance for Group 1 emission 
points. For storage vessels to which the provisions of paragraphs 
(c)(2)(i) through (iii) of this section do not apply (as specified in 
paragraph (c)(2)(iv) of this section), the owner or operator is 
required to comply with the provisions of the applicable monitoring 
plan, and monitoring records may be used to determine compliance.
    (7) The information specified in Sec.  63.108(l)(2) of subpart F of 
this part.
    (d) * * *
    (1) Reports of start-up, shutdown, and malfunction required by 
Sec.  63.10(d)(5). The start-up, shutdown and malfunction reports may 
be submitted on the same schedule as the Periodic Reports required 
under paragraph (c) of this section instead of the schedule specified 
in Sec.  63.10(d)(5). For each source as defined in Sec.  63.101, on 
and after July 15, 2027, this paragraph no longer applies.
* * * * *
    (f) Owners or operators required to keep continuous records by 
Sec. Sec.  63.118, 63.130, 63.147, 63.150, or other sections of this 
subpart shall keep records as specified in paragraphs (f)(1) through 
(f)(7) of this section, unless an alternative recordkeeping system has 
been requested and approved under Sec.  63.151(f) or (g) or Sec.  
63.152(e) or under Sec.  63.8(f), and except as provided in paragraph 
(c)(2)(ii)(C) of this section or in paragraph (g) of this section. If a 
monitoring plan for storage vessels pursuant to Sec.  63.120(d)(2)(i) 
requires continuous records, the monitoring plan shall specify which 
provisions, if any, of paragraphs (f)(1) through (f)(7) of this section 
apply. Any records required to be maintained by this part that are 
submitted electronically via the EPA's CEDRI may be maintained in 
electronic format. This ability to maintain electronic copies does not 
affect the requirement for facilities to make records, data, and 
reports available upon request to a delegated air agency or the EPA as 
part of an on-site compliance evaluation.
* * * * *
    (7) Except as specified in paragraph (f)(7)(vi) of this section 
monitoring data recorded during periods identified in paragraphs 
(f)(7)(i) through (f)(7)(v) of this section shall not be included in 
any average computed under this subpart. Records shall be kept of the 
times and durations of all such periods and any other periods during 
process or control device operation when monitors are not operating.
* * * * *
    (vi) For each source as defined in Sec.  63.101, on and after July 
15, 2027, paragraphs (f)(7)(ii) through (f)(7)(iv) no longer apply.
    (g) * * *
    (1) The owner or operator may retain only the daily average value, 
and is not required to retain more frequent monitored operating 
parameter values, for a monitored parameter with respect to an item of 
equipment, if the requirements of paragraphs (g)(1)(i) through (vi) of 
this section are met. An owner or operator electing to comply with the 
requirements of paragraph (g)(1) of this section shall notify the 
Administrator in the Notification of Compliance Status or, if the 
Notification of Compliance Status has already been submitted, in the 
periodic report immediately preceding implementation of the 
requirements of paragraph (g)(1) of this section.
    (i) The monitoring system is capable of detecting unrealistic or 
impossible data during periods of operation other than startups, 
shutdowns, or malfunctions (e.g., a temperature reading of -200 [deg]C 
on a boiler), and will alert the operator by alarm or other means. The 
owner or operator shall record the occurrence. All instances of the 
alarm or other alert in an operating day constitute a single 
occurrence. For each source as defined in Sec.  63.101, on and after 
July 15, 2027, the phrase ``other than startups, shutdowns, or 
malfunctions (e.g., a temperature reading of -200 [deg]C on a 
boiler),'' in this paragraph no longer applies.
    (ii) The monitoring system generates, updated at least hourly 
throughout each operating day, a running average of the monitoring 
values that have been obtained during that operating day, and the 
capability to observe this average is readily available to the 
Administrator on-site during the operating day. The owner or operator 
shall record the occurrence of any period meeting the criteria in 
paragraphs (g)(1)(ii)(A) through (C) of this section. All instances in 
an operating day constitute a single occurrence.
    (A) The running average is above the maximum or below the minimum 
established limits;
    (B) The running average is based on at least 6 1-hour average 
values; and
    (C) The running average reflects a period of operation other than a 
startup, shutdown, or malfunction. For each source as defined in Sec.  
63.101, on and after July 15, 2027, the phrase ``other than a startup, 
shutdown, or malfunction'' in this paragraph no longer applies.
    (iii) The monitoring system is capable of detecting unchanging data 
during periods of operation other than startups, shutdowns, or 
malfunctions, except in circumstances where the presence of unchanging 
data is the expected operating condition based on past experience 
(e.g., pH in some scrubbers), and will alert the operator by alarm or 
other means. The owner or operator shall record the occurrence. All 
instances of the alarm or other alert in an operating day constitute a 
single occurrence. For each source as defined in Sec.  63.101, on and 
after July 15, 2027, the phrase ``other than startups, shutdowns, or 
malfunctions'' in this paragraph no longer applies.
    (iv) The monitoring system will alert the owner or operator by an 
alarm or other means, if the running average parameter value calculated 
under paragraph (g)(1)(ii) of this section reaches a set point that is 
appropriately related to the established limit for the parameter that 
is being monitored.
    (v) The owner or operator shall verify the proper functioning of 
the monitoring system, including its ability to comply with the 
requirements of paragraph (g)(1) of this section, at the times 
specified in paragraphs (g)(1)(v)(A) through (C) of this section. The 
owner or operator shall document that the required verifications 
occurred.
    (A) Upon initial installation.
    (B) Annually after initial installation.
    (C) After any change to the programming or equipment constituting 
the monitoring system, which might reasonably be expected to alter the 
monitoring system's ability to comply with the requirements of this 
section.
    (vi) The owner or operator shall retain the records identified in 
paragraphs (g)(1)(vi)(A) through (C) of this section.
    (A) Identification of each parameter, for each item of equipment, 
for which the owner or operator has elected to comply with the 
requirements of paragraph (g) of this section.
    (B) A description of the applicable monitoring system(s), and of 
how compliance will be achieved with each requirement of paragraph 
(g)(1)(i) through (g)(1)(v) of this section. The description shall 
include monitoring equipment manufacturer(s) and model number(s) and 
the pollutant or parameter monitored, and identify the location and 
format (e.g., on-line

[[Page 43212]]

storage; log entries) for each required record. If the description 
changes, the owner or operator shall retain both the current and the 
most recent superseded description. The description, and the most 
recent superseded description, shall be retained as provided in Sec.  
63.103(c) of subpart F of this part, except as provided in paragraph 
(g)(1)(vi)(D) of this section.
    (C) A description, and the date, of any change to the monitoring 
system that would reasonably be expected to affect its ability to 
comply with the requirements of paragraph (g)(1) of this section.
    (D) Owners and operators subject to paragraph (g)(1)(vi)(B) of this 
section shall retain the current description of the monitoring system 
as long as the description is current, but not less than 5 years from 
the date of its creation. The current description shall, at all times, 
be retained on-site or be accessible from a central location by 
computer or other means that provides access within 2 hours after a 
request. The owner or operator shall retain the most recent superseded 
description at least until 5 years from the date of its creation. The 
superseded description shall be retained on-site (or accessible from a 
central location by computer that provides access within 2 hours after 
a request) at least 6 months after its creation. Thereafter, the 
superseded description may be stored off-site.
    (2) If an owner or operator has elected to implement the 
requirements of paragraph (g)(1) of this section, and a period of 6 
consecutive months has passed without an excursion as defined in 
paragraph (g)(2)(iv) of this section, the owner or operator is no 
longer required to record the daily average value for that parameter 
for that unit of equipment, for any operating day when the daily 
average value is less than the maximum, or greater than the minimum 
established limit. With approval by the Administrator, monitoring data 
generated prior to the compliance date of this subpart shall be 
credited toward the period of 6 consecutive months, if the parameter 
limit and the monitoring was required and/or approved by the 
Administrator.
    (i) If the owner or operator elects not to retain the daily average 
values, the owner or operator shall notify the Administrator in the 
next periodic report. The notification shall identify the parameter and 
unit of equipment.
    (ii) If, on any operating day after the owner or operator has 
ceased recording daily averages as provided in paragraph (g)(2) of this 
section, there is an excursion as defined in paragraph (g)(2)(iv) of 
this section, the owner or operator shall immediately resume retaining 
the daily average value for each day, and shall notify the 
Administrator in the next periodic report. The owner or operator shall 
continue to retain each daily average value until another period of 6 
consecutive months has passed without an excursion as defined in 
paragraph (g)(2)(iv) of this section.
    (iii) The owner or operator shall retain the records specified in 
paragraphs (g)(1) (i), (ii), (iii), (iv), (v), and (vi) of this 
section. For any calendar week, if compliance with paragraphs (g)(1) 
(i), (ii), (iii), and (iv) of this section does not result in retention 
of a record of at least one occurrence or measured parameter value, the 
owner or operator shall record and retain at least one parameter value 
during a period of operation other than a startup, shutdown, or 
malfunction. For each source as defined in Sec.  63.101, on and after 
July 15, 2027, the phrase ``other than a startup, shutdown, or 
malfunction'' in this paragraph no longer applies.
    (iv) For purposes of paragraph (g) of this section, an excursion 
means that the daily average value of monitoring data for a parameter 
is greater than the maximum, or less than the minimum established 
value, except as provided in paragraphs (g)(2)(iv)(A) and (B) of this 
section.
    (A) The daily average value during any startup, shutdown, or 
malfunction shall not be considered an excursion for purposes of this 
paragraph (g)(2), if the owner or operator operates the source during 
such periods in accordance with Sec.  63.102(a)(4). For each source as 
defined in Sec.  63.101, on and after July 15, 2027, this paragraph no 
longer applies.
    (B) An excused excursion, as described in Sec.  63.152(c)(2)(ii)(B) 
and (C), shall not be considered an excursion for purposes of this 
paragraph (g)(2).
    (h) Beginning no later than July 15, 2024, owners and operators 
must submit performance test reports in accordance with this paragraph. 
Unless otherwise specified in this subpart, within 60 days after the 
date of completing each performance test required by this subpart, 
owners and operators must submit the results of the performance test 
following the procedures specified in Sec.  63.9(k). Data collected 
using test methods supported by the EPA's Electronic Reporting Tool 
(ERT) as listed on the EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at 
the time of the test must be submitted in a file format generated 
through the use of the EPA's ERT. Alternatively, owners and operators 
may submit an electronic file consistent with the extensible markup 
language (XML) schema listed on the EPA's ERT website. Data collected 
using test methods that are not supported by the EPA's ERT as listed on 
the EPA's ERT website at the time of the test must be included as an 
attachment in the ERT or alternate electronic file.

0
90. Amend Sec.  63.153 by revising paragraph (c) introductory text and 
adding paragraph (c)(5) as follows:


Sec.  63.153  Implementation and enforcement.

* * * * *
    (c) The authorities that cannot be delegated to State, local, or 
Tribal agencies are as specified in paragraphs (c)(1) through (5) of 
this section.
* * * * *
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.

0
91. Revise table 3 to subpart G to read as follows:

       Table 3 to Subpart G of Part 63--Process Vents--Monitoring,
    Recordkeeping, and Reporting Requirements for Control Devices and
                            Recapture Devices
------------------------------------------------------------------------
                                                      Recordkeeping and
                                                          reporting
  Control or recapture device     Parameters to be     requirements for
                                    monitored \a\         monitored
                                                          parameters
------------------------------------------------------------------------
Thermal incinerator, other than  Firebox             1. Continuous
 a thermal oxidizer used to       temperature \b\     records.\c\
 comply with Sec.   63.124.       [63.114(a)(1)(i)]. 2. Record and
                                                      report the firebox
                                                      temperature
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average firebox
                                                      temperature for
                                                      each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average
                                                      temperatures that
                                                      are outside the
                                                      range established
                                                      in the NCS or
                                                      operating permit
                                                      and all operating
                                                      days when
                                                      insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Thermal oxidizer used to comply  Combustion chamber  1. Continuous
 with Sec.   63.124.              temperature         records.\c\
                                  [63.124(b)(5)(i)]. 2. Record and
                                                      report the
                                                      combustion chamber
                                                      temperature
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\

[[Page 43213]]

 
                                                     3. Record each 1-
                                                      hour block average
                                                      firebox
                                                      temperature for
                                                      each operating
                                                      day.
                                                     4. Report all 1-
                                                      hour block
                                                      temperatures that
                                                      are outside the
                                                      range established
                                                      in the NCS or
                                                      operating permit
                                                      and all operating
                                                      days when
                                                      insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Thermal oxidizer used to comply  Flue gas flow rate  1. Continuous
 with Sec.   63.124 (Continued).  [63.124(b)(5)(ii)   records.\c\
                                  ].                 2. Record and
                                                      report the flue
                                                      gas flow rate
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record each 1-
                                                      hour block average
                                                      flue gas flow rate
                                                      for each operating
                                                      day.
                                                     4. Report all 1-
                                                      hour block flue
                                                      gas flow rates
                                                      that are outside
                                                      the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Catalytic incinerator..........  Temperature         1. Continuous
                                  upstream and        records.\c\
                                  downstream of the  2. Record and
                                  catalyst bed        report the
                                  [63.114(a)(1)(ii)   upstream and
                                  ].                  downstream
                                                      temperatures and
                                                      the temperature
                                                      difference across
                                                      the catalyst bed
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average upstream
                                                      temperature and
                                                      temperature
                                                      difference across
                                                      the catalyst bed
                                                      for each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average upstream
                                                      temperatures that
                                                      are outside the
                                                      range established
                                                      in the NCS or
                                                      operating permit--
                                                      PR.
                                                     5. Report all daily
                                                      average
                                                      temperature
                                                      differences across
                                                      the catalyst bed
                                                      that are outside
                                                      the range
                                                      established in the
                                                      NCS or operating
                                                      permit--PR.\g\
                                                     6. Report all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected.\f\
Flare (if meeting the            Presence of a       1. Hourly records
 requirements of Sec.             flame at the        of whether the
 63.11(b)).                       pilot light [Sec.   monitor was
                                    63.114(a)(2)].    continuously
                                                      operating and
                                                      whether the pilot
                                                      flame was
                                                      continuously
                                                      present during
                                                      each hour.
                                                     2. Record and
                                                      report the
                                                      presence of a
                                                      flame at the pilot
                                                      light over the
                                                      full period of the
                                                      compliance
                                                      determination--NCS
                                                      .\d\
                                                     3. Record the times
                                                      and durations of
                                                      all periods when
                                                      all pilot flames
                                                      are absent or the
                                                      monitor is not
                                                      operating.
                                                     4. Report the times
                                                      and durations of
                                                      all periods when
                                                      all pilot flames
                                                      of a flare are
                                                      absent--PR.\g\
Flare (if meeting the            The parameters are  1. Records as
 requirements of Sec.   63.108).  specified in Sec.   specified in Sec.
                                    63.108.            63.108(m) of
                                                      subpart F of this
                                                      part.
                                                     2. Report
                                                      information as
                                                      specified in Sec.
                                                       63.108(l) of
                                                      subpart F of this
                                                      part--PR.\g\
Boiler or process heater with a  Firebox             1. Continuous
 design heat input capacity       temperature \b\     records.\c\
 less than 44 megawatts and       [Sec.              2. Record and
 vent stream is not introduced    63.114(a)(3)].      report the firebox
 with or as the primary fuel.                         temperature
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average firebox
                                                      temperature for
                                                      each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average firebox
                                                      temperatures that
                                                      are outside the
                                                      range established
                                                      in the NCS or
                                                      operating permit
                                                      and all operating
                                                      days when
                                                      insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Scrubber for halogenated vent    pH of scrubber      1. Continuous
 streams (Note: Controlled by a   effluent [Sec.      records.\c\
 combustion device other than a   63.114(a)(4)(i)],  2. Record and
 flare).                          and                 report the pH of
                                                      the scrubber
                                                      effluent averaged
                                                      over the full
                                                      period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average pH of the
                                                      scrubber effluent
                                                      for each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average pH values
                                                      of the scrubber
                                                      effluent that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Scrubber for halogenated vent    Scrubber liquid     1. Continuous
 streams (Note: Controlled by a   and gas flow        records of
 combustion device other than a   rates [Sec.         scrubber liquid
 flare) (Continued).              63.114(a)(4)(ii)].  flow rate.\c\
                                                     2. Record and
                                                      report the
                                                      scrubber liquid/
                                                      gas ratio averaged
                                                      over the full
                                                      period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average scrubber
                                                      liquid/gas ratio
                                                      for each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average scrubber
                                                      liquid/gas ratios
                                                      that are outside
                                                      the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
All control devices............  Presence of flow    1. Hourly records
                                  diverted to the     of whether the
                                  atmosphere from     flow indicator was
                                  the control         operating and
                                  device [Sec.        whether diversion
                                  63.114(d)(1)] or    was detected at
                                                      any time during
                                                      each hour.
                                                     2. Record and
                                                      report the times
                                                      and durations of
                                                      all periods when
                                                      the vent stream is
                                                      diverted through a
                                                      bypass line or the
                                                      monitor is not
                                                      operating--PR.\g\
                                                     3. For each source
                                                      as defined in Sec.
                                                        63.101,
                                                      beginning no later
                                                      than the
                                                      compliance dates
                                                      specified in Sec.
                                                       63.100(k)(10),
                                                      record and report
                                                      the start date,
                                                      start time,
                                                      duration in hours,
                                                      estimate of the
                                                      volume of gas in
                                                      standard cubic
                                                      feet, the
                                                      concentration of
                                                      organic HAP in the
                                                      gas in parts per
                                                      million by volume
                                                      and the resulting
                                                      mass emissions of
                                                      organic HAP in
                                                      pounds that bypass
                                                      a control device.
                                                      For periods when
                                                      the flow indicator
                                                      is not operating,
                                                      report the start
                                                      date, start time,
                                                      and duration in
                                                      hours--PR.\g\
All control devices (Continued)  Monthly             1. Records that
                                  inspections of      monthly
                                  sealed valves       inspections were
                                  [Sec.               performed.
                                  63.114(d)(2)].     2. Record and
                                                      report all monthly
                                                      inspections that
                                                      show the valves
                                                      are moved to the
                                                      diverting position
                                                      or the seal has
                                                      been changed--
                                                      PR.\g\

[[Page 43214]]

 
                                                     3. For each source
                                                      as defined in Sec.
                                                        63.101,
                                                      beginning no later
                                                      than the
                                                      compliance dates
                                                      specified in Sec.
                                                       63.100(k)(10),
                                                      record and report
                                                      the start date,
                                                      start time,
                                                      duration in hours,
                                                      estimate of the
                                                      volume of gas in
                                                      standard cubic
                                                      feet, the
                                                      concentration of
                                                      organic HAP in the
                                                      gas in parts per
                                                      million by volume
                                                      and the resulting
                                                      mass emissions of
                                                      organic HAP in
                                                      pounds that bypass
                                                      a control device.
                                                      For periods when
                                                      the flow indicator
                                                      is not operating,
                                                      report the start
                                                      date, start time,
                                                      and duration in
                                                      hours--PR.\g\
All recapture devices (as an     Concentration       1. Continuous
 alternative to the below for     level or reading    records.\c\
 absorbers, condensers, and       indicated by an    2. Record and
 carbon adsorbers).               organic             report the
                                  monitoring device   concentration
                                  at the outlet of    level or reading
                                  the recovery        averaged over the
                                  device [Sec.        full period of the
                                  63.114(a)(5)(i)].   performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average
                                                      concentration
                                                      level or reading
                                                      for each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average
                                                      concentration
                                                      levels or readings
                                                      that are outside
                                                      the range
                                                      established in the
                                                      NCS or operating
                                                      permit--PR.\g\
Absorber \h\...................  Exit temperature    1. Continuous
                                  of the absorbing    records.\c\
                                  liquid [Sec.       2. Record and
                                  63.114(a)(5)(ii)]   report the exit
                                  , and               temperature of the
                                                      absorbing liquid
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average exit
                                                      temperature of the
                                                      absorbing liquid
                                                      for each operating
                                                      day.\e\
                                                     4. Report all the
                                                      daily average exit
                                                      temperatures of
                                                      the absorbing
                                                      liquid that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit--PR.\g\
Absorber \h\ (Continued).......  Exit specific       1. Continuous
                                  gravity [Sec.       records.\c\
                                  63.114(a)(5)(ii)]  2. Record and
                                                      report the exit
                                                      specific gravity
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average exit
                                                      specific gravity
                                                      for each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average exit
                                                      specific gravity
                                                      values that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit--PR.\g\
Condenser \h\..................  Exit (product       1. Continuous
                                  side) temperature   records.\c\
                                  [Sec.              2. Record and
                                  63.114(a)(5)(iii)   report the exit
                                  ].                  temperature
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average exit
                                                      temperature for
                                                      each operating day
                                                      \e\.
                                                     4. Report all daily
                                                      average exit
                                                      temperatures that
                                                      are outside the
                                                      range established
                                                      in the NCS or
                                                      operating permit--
                                                      PR.\g\
Carbon adsorber \h\............  Total regeneration  1. Record of total
                                  stream mass or      regeneration
                                  volumetric flow     stream mass or
                                  during carbon bed   volumetric flow
                                  regeneration        for each carbon
                                  cycle(s) [Sec.      bed regeneration
                                  63.114(a)(5)(iv)]   cycle.
                                  , and              2. Record and
                                                      report the total
                                                      regeneration
                                                      stream mass or
                                                      volumetric flow
                                                      during each carbon
                                                      bed regeneration
                                                      cycle during the
                                                      period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Report all
                                                      carbon bed
                                                      regeneration
                                                      cycles when the
                                                      total regeneration
                                                      stream mass or
                                                      volumetric flow is
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit--PR.\g\
Carbon adsorber \h\ (Continued)  Temperature of the  1. Records of the
                                  carbon bed after    temperature of the
                                  regeneration [and   carbon bed after
                                  within 15 minutes   each regeneration.
                                  of completing any  2. Record and
                                  cooling cycle(s)]   report the
                                  [Sec.               temperature of the
                                  63.114(a)(5)(iv)].  carbon bed after
                                                      each regeneration
                                                      during the period
                                                      of the performance
                                                      test--NCS.\d\
                                                     3. Report all
                                                      carbon bed
                                                      regeneration
                                                      cycles during
                                                      which temperature
                                                      of the carbon bed
                                                      after regeneration
                                                      is outside the
                                                      range established
                                                      in the NCS or
                                                      operating permit--
                                                      PR.\g\
Carbon adsorber \h\ (Continued)  Outlet HAP or TOC   For each
                                  concentration       nonregenerative
                                  [Sec.               adsorber and
                                  63.114(a)(5)(v)].   regenerative
                                                      adsorber that is
                                                      regenerated
                                                      offsite subject to
                                                      the requirements
                                                      in Sec.
                                                      63.114(a)(5)(v),
                                                      the owner or
                                                      operator must
                                                      record each outlet
                                                      HAP or TOC
                                                      concentration
                                                      measured according
                                                      to Sec.  Sec.
                                                      63.114(a)(5)(v)(B)
                                                      and (C).
Carbon adsorber\h\ (Continued).  Adsorbent           1. For each
                                  replacement [Sec.   nonregenerative
                                                      adsorber and
                                  63.114(a)(5)(v)].   regenerative
                                                      adsorber that is
                                                      regenerated
                                                      offsite subject to
                                                      the requirements
                                                      in Sec.
                                                      63.114(a)(5)(v),
                                                      the owner or
                                                      operator must
                                                      record date and
                                                      time the adsorbent
                                                      was last replaced.
Carbon adsorber \h\ (Continued)  Breakthrough [Sec.  For each
                                                      nonregenerative
                                  63.114(a)(5)(v)].   adsorber and
                                                      regenerative
                                                      adsorber that is
                                                      regenerated
                                                      offsite subject to
                                                      the requirements
                                                      in Sec.
                                                      63.114(a)(5)(v),
                                                      the owner or
                                                      operator must:
                                                     1. Record
                                                      breakthrough limit
                                                      and bed life
                                                      established
                                                      according to Sec.
                                                       63.114(a)(5)(v)(A
                                                      ).
                                                     2. Report the date
                                                      of each instance
                                                      when breakthrough,
                                                      as defined in Sec.
                                                        63.101, is
                                                      detected between
                                                      the first and
                                                      second adsorber
                                                      and the adsorber
                                                      is not replaced
                                                      according to Sec.
                                                       63.114(a)(5)(v)(A
                                                      )(1)--PR.\g\
Scrubber with a reactant tank    Liquid-to-gas       1. Continuous
 used to comply with Sec.         ratio [Sec.         records.\c\
 63.124.                          63.124(b)(4)(i)].  2. Record and
                                                      report the L/G of
                                                      the scrubber
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record each 1-
                                                      hour block L/G of
                                                      the scrubber for
                                                      each operating
                                                      day.
                                                     4. Report all 1-
                                                      hour block L/G
                                                      values of the
                                                      scrubber that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Scrubber with a reactant tank    In lieu of liquid-  1. Continuous
 used to comply with Sec.         to-gas ratio,       records.\c\
 63.124 (Continued).              scrubber total     2. Record and
                                  liquid flow rate    report both the
                                  and gas flow rate   total scrubber
                                  through scrubber    liquid flow rate
                                  [Sec.               and gas flow rate
                                  63.124(b)(4)(i)].   through the
                                                      scrubber averaged
                                                      over the full
                                                      period of the
                                                      performance test--
                                                      NCS.\d\

[[Page 43215]]

 
                                                     3. Record each 1-
                                                      hour block total
                                                      scrubber liquid
                                                      flow rate and each
                                                      1-hour block gas
                                                      flow rate through
                                                      the scrubber for
                                                      each operating
                                                      day.
                                                     4. Report all 1-
                                                      hour block total
                                                      scrubber liquid
                                                      flow rate values
                                                      and all 1-hour
                                                      block gas flow
                                                      rate through the
                                                      scrubber values
                                                      that are outside
                                                      the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Scrubber with a reactant tank    pH of liquid in     1. Continuous
 used to comply with Sec.         reactant tank       records.\c\
 63.124 (Continued).              [Sec.              2. Record and
                                  63.124(b)(4)(ii)].  report the pH of
                                                      liquid in reactant
                                                      tank averaged over
                                                      the full period of
                                                      the performance
                                                      test--NCS.\d\
                                                     3. Record each 1-
                                                      hour block pH of
                                                      liquid in reactant
                                                      tank for each
                                                      operating day.
                                                     4. Report all 1-
                                                      hour block values
                                                      of the pH of
                                                      liquid in reactant
                                                      tank that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Scrubber with a reactant tank    Pressure drop       1. Continuous
 used to comply with Sec.         [Sec.               records.\c\
 63.124 (Continued).              63.124(b)(4)(iii)  2. Record and
                                  ].                  report the
                                                      pressure drop of
                                                      the scrubber
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record each 1-
                                                      hour block
                                                      pressure drop of
                                                      the scrubber for
                                                      each operating
                                                      day.
                                                     4. Report all 1-
                                                      hour block
                                                      pressure drop
                                                      values that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Scrubber with a reactant tank    Temperature of      1. Continuous
 used to comply with Sec.         scrubbing liquid    records.\c\
 63.124 (Continued).              entering column    2. Record and
                                  [Sec.               report the
                                  63.124(b)(4)(iv)].  temperature of
                                                      scrubbing liquid
                                                      entering column
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record each 1-
                                                      hour block
                                                      temperature of
                                                      scrubbing liquid
                                                      entering column
                                                      for each operating
                                                      day.
                                                     4. Report all 1-
                                                      hour block values
                                                      of the temperature
                                                      of scrubbing
                                                      liquid entering
                                                      column that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected\f\--
                                                      PR.\g\
Scrubber with a reactant tank    Liquid feed         1. Continuous
 used to comply with Sec.         pressure [Sec.      records.\c\
 63.124 (Continued).              63.124(b)(4)(v)].  2. Record and
                                                      report the liquid
                                                      feed pressure of
                                                      the scrubber
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record each 1-
                                                      hour block liquid
                                                      feed pressure of
                                                      the scrubber for
                                                      each operating
                                                      day.
                                                     4. Report all 1-
                                                      hour block liquid
                                                      feed pressure
                                                      values that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Sorbent injection..............  Sorbent injection   1. Continuous
                                  rate \b\ [Sec.      records.\c\
                                  63.114(a)(6)(i)].  2. Record and
                                                      report the sorbent
                                                      injection rate
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average sorbent
                                                      injection rate for
                                                      each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average sorbent
                                                      injection rates
                                                      that are outside
                                                      the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Sorbent injection (Continued)..  Carrier gas flow    1. Continuous
                                  rate \b\ [Sec.      records.\c\
                                  63.114(a)(6)(ii)]. 2. Record and
                                                      report the carrier
                                                      gas flow rate
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average carrier
                                                      gas flow rate for
                                                      each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average carrier
                                                      gas flow rates
                                                      that are outside
                                                      the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
------------------------------------------------------------------------
\a\ Regulatory citations are listed in brackets.
\b\ Monitor may be installed in the firebox or in the ductwork
  immediately downstream of the firebox before any substantial heat
  exchange is encountered.
\c\ ``Continuous records'' is defined in Sec.   63.111 of this subpart.
\d\ NCS = Notification of Compliance Status described in Sec.   63.152
  of this subpart.
\e\ The daily average is the average of all recorded parameter values
  for the operating day. If all recorded values during an operating day
  are within the range established in the NCS or operating permit, a
  statement to this effect can be recorded instead of the daily average.
\f\ The periodic reports shall include the duration of periods when
  monitoring data is not collected for each excursion as defined in Sec.
    63.152(c)(2)(ii)(A) of this subpart.
\g\ PR = Periodic Reports described in Sec.   63.152 of this subpart.
\h\ Alternatively, these devices may comply with the organic monitoring
  device provisions listed at this table under ``All recapture
  devices.''.


0
92. Revise the heading of table 4 to subpart G to read as follows:

Table 4 to Subpart G of Part 63--Process Vents--Monitoring, 
Recordkeeping, and Reporting Requirements for Maintaining a TRE Index 
Value >1.0 and. <=4.0 [No Longer Applicable in Accordance With Sec.  
63.113(a)(4)]

* * * * *
0
93. Revise table 5 to subpart G to read as follows:

[[Page 43216]]



  Table 5 to Subpart G of Part 63--Group 1 Storage Vessels at Existing
                                 Sources
------------------------------------------------------------------------
                                                      Vapor pressure \a\
           Vessel capacity (cubic meters)                (kilopascals)
------------------------------------------------------------------------
75 <= capacity <151 \b\.............................          \b\ >=13.1
38 <= capacity <151 \c\.............................           \c\ >=6.9
151 <= capacity.....................................               >=5.2
------------------------------------------------------------------------
\a\ Maximum true vapor pressure of total organic HAP at storage
  temperature.
\b\ For each source as defined in Sec.   63.101, beginning no later than
  the compliance dates specified in Sec.   63.100(k)(10), these vessel
  capacity and vapor pressure criterion no longer apply.
\c\ For each source as defined in Sec.   63.101, beginning no later than
  the compliance dates specified in Sec.   63.100(k)(10), these vessel
  capacity and vapor pressure criterion apply.


0
94. Revise table 6 to subpart G to read as follows:

 Table 6 to Subpart G of Part 63--Group 1 Storage Vessels at New Sources
------------------------------------------------------------------------
                                                      Vapor pressure \a\
           Vessel capacity (cubic meters)                (kilopascals)
------------------------------------------------------------------------
38 <= capacity <151\b\..............................           >=13.1\b\
38 <= capacity <151\c\..............................            >=6.9\c\
151 <= capacity.....................................               >=0.7
------------------------------------------------------------------------
\a\ Maximum true vapor pressure of total organic HAP at storage
  temperature.
\b\ For each source as defined in Sec.   63.101, beginning no later than
  the compliance dates specified in Sec.   63.100(k)(10), these vessel
  capacity and vapor pressure criterion no longer apply.
\c\ For each source as defined in Sec.   63.101, beginning no later than
  the compliance dates specified in Sec.   63.100(k)(10), these vessel
  capacity and vapor pressure criterion apply.


0
95. Revise table 7 to subpart G to read as follows:

    Table 7 to Subpart G of Part 63--Transfer Operations--Monitoring,
 Recordkeeping, and Reporting Requirements for Complying With 98 Weight-
Percent Reduction of Total Organic Hazardous Air Pollutants Emissions or
                a Limit of 20 Parts per Million by Volume
------------------------------------------------------------------------
                                                      Recordkeeping and
                                                          reporting
         Control device           Parameters to be     requirements for
                                    monitored \a\         monitored
                                                          parameters
------------------------------------------------------------------------
Thermal incinerator............  Firebox             1. Continuous
                                  temperature \b\     records \c\ during
                                  [Sec.               loading.
                                  63.127(a)(1)(i)].  2. Record and
                                                      report the firebox
                                                      temperature
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.\d\
                                                     3. Record the daily
                                                      average firebox
                                                      temperature for
                                                      each operating
                                                      day.\e\
                                                     4. Report daily
                                                      average
                                                      temperatures that
                                                      are outside the
                                                      range established
                                                      in the NCS or
                                                      operating permit
                                                      and all operating
                                                      days when
                                                      insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.\g\
Catalytic incinerator..........  Temperature         1. Continuous
                                  upstream and        records during
                                  downstream of the   loading.
                                  catalyst bed       2. Record and
                                  [Sec.               report the
                                  63.127(a)(1)(ii)].  upstream and
                                                      downstream
                                                      temperatures and
                                                      the temperature
                                                      difference across
                                                      the catalyst bed
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.
                                                     3. Record the daily
                                                      average upstream
                                                      temperature and
                                                      temperature
                                                      difference across
                                                      catalyst bed for
                                                      each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average upstream
                                                      temperatures that
                                                      are outside the
                                                      range established
                                                      in the NCS or
                                                      operating permit--
                                                      PR.
                                                     5. Report all daily
                                                      average
                                                      temperature
                                                      differences across
                                                      the catalyst bed
                                                      that are outside
                                                      the range
                                                      established in the
                                                      NCS or operating
                                                      permit--PR.
                                                     6. Report all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected.\f\
Boiler or process heater with a  Firebox             1. Continuous
 design heat input capacity       temperature \b\     records during
 less than 44 megawatts and       [Sec.               loading.
 vent stream is not introduced    63.127(a)(3)].     2. Record and
 with or as the primary fuel.                         report the firebox
                                                      temperature
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.
                                                     3. Record the daily
                                                      average firebox
                                                      temperature for
                                                      each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average firebox
                                                      temperatures that
                                                      are outside the
                                                      range established
                                                      in the NCS or
                                                      operating permit
                                                      and all operating
                                                      days when
                                                      insufficient data
                                                      are collected\f\--
                                                      PR.
Flare (if meeting the            Presence of a       1. Hourly records
 requirements of Sec.             flame at the        of whether the
 63.126(b)(2)(i)).                pilot light [Sec.   monitor was
                                    63.127(a)(2)].    continuously
                                                      operating and
                                                      whether the pilot
                                                      flame was
                                                      continuously
                                                      present during
                                                      each hour.
                                                     2. Record and
                                                      report the
                                                      presence of a
                                                      flame at the pilot
                                                      light over the
                                                      full period of the
                                                      compliance
                                                      determination--NCS
                                                      .
                                                     3. Record the times
                                                      and durations of
                                                      all periods when
                                                      all pilot flames
                                                      are absent or the
                                                      monitor is not
                                                      operating.

[[Page 43217]]

 
                                                     4. Report the
                                                      duration of all
                                                      periods when all
                                                      pilot flames of a
                                                      flare are absent--
                                                      PR.
Flare (if meeting the            The parameters are  1. Records as
 requirements of Sec.   63.108).  specified in Sec.   specified in Sec.
                                    63.108.            63.108(m) of
                                                      subpart F of this
                                                      part.
                                                     2. Report
                                                      information as
                                                      specified in Sec.
                                                       63.108(l) of
                                                      subpart F of this
                                                      part--PR.
Scrubber for halogenated vent    pH of scrubber      1. Continuous
 streams (Note: Controlled by a   effluent [Sec.      records during
 combustion device other than a   63.127(a)(4)(i)],   loading.
 flare).                          and.               2. Record and
                                                      report the pH of
                                                      the scrubber
                                                      effluent averaged
                                                      over the full
                                                      period of the
                                                      performance test--
                                                      NCS.
                                                     3. Record the daily
                                                      average pH of the
                                                      scrubber effluent
                                                      for each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average pH values
                                                      of the scrubber
                                                      effluent that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.
                                 Scrubber liquid     1. Continuous
                                  and gas flow        records during
                                  rates [Sec.         loading of
                                  63.127(a)(4)(ii)].  scrubber liquid
                                                      flow rate.
                                                     2. Record and
                                                      report the
                                                      scrubber liquid/
                                                      gas ratio averaged
                                                      over the full
                                                      period of the
                                                      performance test--
                                                      NCS.
                                                     3. Record the daily
                                                      average scrubber
                                                      liquid/gas ratio
                                                      for each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average scrubber
                                                      liquid/gas ratios
                                                      that are outside
                                                      the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.
Absorber \h\...................  Exit temperature    1. Continuous
                                  of the absorbing    records during
                                  liquid [Sec.        loading.
                                  63.127(b)(1)],     2. Record and
                                  and                 report the exit
                                                      temperature of the
                                                      absorbing liquid
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.
                                                     3. Record the daily
                                                      average exit
                                                      temperature of the
                                                      absorbing liquid
                                                      for each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average exit
                                                      temperatures of
                                                      the absorbing
                                                      liquid that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.
                                 Exit specific       1. Continuous
                                  gravity [Sec.       records during
                                  63.127(b)(1)].      loading.
                                                     2. Record and
                                                      report the exit
                                                      specific gravity
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.
                                                     3. Record the daily
                                                      average exit
                                                      specific gravity
                                                      for each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average exit
                                                      specific gravity
                                                      values that are
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.
Condenser \h\..................  Exit (product       1. Continuous
                                  side) temperature   records during
                                  [Sec.               loading.
                                  63.127(b)(2)].     2. Record and
                                                      report the exit
                                                      temperature
                                                      averaged over the
                                                      full period of the
                                                      performance test--
                                                      NCS.
                                                     3. Record the daily
                                                      average exit
                                                      temperature for
                                                      each operating
                                                      day.\e\
                                                     4. Report all daily
                                                      average exit
                                                      temperatures that
                                                      are outside the
                                                      range established
                                                      in the NCS or
                                                      operating permit
                                                      and all operating
                                                      days when
                                                      insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.
Carbon adsorber \h\............  Total regeneration  1. Record of total
                                  stream mass or      regeneration
                                  volumetric or       stream mass or
                                  volumetric flow     volumetric flow
                                  during carbon bed   for each carbon
                                  regeneration        bed regeneration
                                  cycle(s) [Sec.      cycle.
                                  63.127(b)(3)],     2. Record and
                                  and                 report the total
                                                      regeneration
                                                      stream mass or
                                                      volumetric flow
                                                      during each carbon
                                                      bed regeneration
                                                      cycle during the
                                                      period of the
                                                      performance test--
                                                      NCS.
                                                     3. Report all
                                                      carbon bed
                                                      regeneration
                                                      cycles when the
                                                      total regeneration
                                                      stream mass or
                                                      volumetric flow is
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.
                                 Temperature of the  1. Records of the
                                  carbon bed after    temperature of the
                                  regeneration [and   carbon bed after
                                  within 15 minutes   each regeneration.
                                  of completing any  2. Record and
                                  cooling cycle(s)]   report the
                                  [Sec.               temperature of the
                                  63.127(b)(3)].      carbon bed after
                                                      each regeneration
                                                      during the period
                                                      of the performance
                                                      test--NCS.
                                                     3. Report all the
                                                      carbon bed
                                                      regeneration
                                                      cycles during
                                                      which the
                                                      temperature of the
                                                      carbon bed after
                                                      regeneration is
                                                      outside the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.
                                 Outlet HAP or TOC   For each
                                  concentration       nonregenerative
                                  [Sec.               adsorber and
                                  63.127(b)(4)].      regenerative
                                                      adsorber that is
                                                      regenerated
                                                      offsite subject to
                                                      the requirements
                                                      in Sec.
                                                      63.127(b)(4), the
                                                      owner or operator
                                                      must record each
                                                      outlet HAP or TOC
                                                      concentration
                                                      measured according
                                                      to Sec.  Sec.
                                                      63.127(b)(4)(ii)
                                                      and (iii).
                                 Adsorbent           1. For each
                                  replacement [Sec.   nonregenerative
                                    63.127(b)(4)].    adsorber and
                                                      regenerative
                                                      adsorber that is
                                                      regenerated
                                                      offsite subject to
                                                      the requirements
                                                      in Sec.
                                                      63.127(b)(4), the
                                                      owner or operator
                                                      must record date
                                                      and time the
                                                      adsorbent was last
                                                      replaced.
                                 Breakthrough [Sec.  For each
                                    63.127(b)(4)].    nonregenerative
                                                      adsorber and
                                                      regenerative
                                                      adsorber that is
                                                      regenerated
                                                      offsite subject to
                                                      the requirements
                                                      in Sec.
                                                      63.127(b)(4), the
                                                      owner or operator
                                                      must:
                                                     1. Record
                                                      breakthrough limit
                                                      and bed life
                                                      established
                                                      according to Sec.
                                                       63.127(b)(4)(i).
                                                     2. Report the date
                                                      of each instance
                                                      when breakthrough,
                                                      as defined in Sec.
                                                        63.101, is
                                                      detected between
                                                      the first and
                                                      second adsorber
                                                      and the adsorber
                                                      is not replaced
                                                      according to Sec.
                                                       63.127(b)(4)(iii)
                                                      (A)--PR.

[[Page 43218]]

 
All recovery devices (as an      Concentration       1. Continuous
 alternative to the above).       level or reading    records during
                                  indicated by an     loading.
                                  organic            2. Record and
                                  monitoring device   report the
                                  at the outlet of    concentration
                                  the recovery        level or reading
                                  device [Sec.        averaged over the
                                  63.127(b)].         full period of the
                                                      performance test--
                                                      NCS.
                                                     3. Record the daily
                                                      average
                                                      concentration
                                                      level or reading
                                                      for each operating
                                                      day.\d\
                                                     4. Report all daily
                                                      average
                                                      concentration
                                                      levels or readings
                                                      that are outside
                                                      the range
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      operating days
                                                      when insufficient
                                                      monitoring data
                                                      are collected \f\--
                                                      PR.
All control devices and vapor    Presence of flow    1. Hourly records
 balancing systems.               diverted to the     of whether the
                                  atmosphere from     flow indicator was
                                  the control         operating and
                                  device [Sec.        whether a
                                  63.127(d)(1)] or    diversion was
                                                      detected at any
                                                      time during each
                                                      hour.
                                                     2. Record and
                                                      report the
                                                      duration of all
                                                      periods when the
                                                      vent stream is
                                                      diverted through a
                                                      bypass line or the
                                                      monitor is not
                                                      operating--PR.
                                                     3. For each source
                                                      as defined in Sec.
                                                        63.101,
                                                      beginning no later
                                                      than the
                                                      compliance dates
                                                      specified in Sec.
                                                       63.100(k)(10),
                                                      record and report
                                                      the start date,
                                                      start time,
                                                      duration in hours,
                                                      estimate of the
                                                      volume of gas in
                                                      standard cubic
                                                      feet, the
                                                      concentration of
                                                      organic HAP in the
                                                      gas in parts per
                                                      million by volume
                                                      and the resulting
                                                      mass emissions of
                                                      organic HAP in
                                                      pounds that bypass
                                                      a control device.
                                                      For periods when
                                                      the flow indicator
                                                      is not operating,
                                                      report the start
                                                      date, start time,
                                                      and duration in
                                                      hours--PR.
                                 Monthly             1. Records that
                                  inspections of      monthly
                                  sealed valves       inspections were
                                  [Sec.               performed.
                                  63.127(d)(2)].     2. Record and
                                                      report all monthly
                                                      inspections that
                                                      show the valves
                                                      are moved to the
                                                      diverting position
                                                      or the seal has
                                                      been changed.
                                                     3. For each source
                                                      as defined in Sec.
                                                        63.101,
                                                      beginning no later
                                                      than the
                                                      compliance dates
                                                      specified in Sec.
                                                       63.100(k)(10),
                                                      record and report
                                                      the start date,
                                                      start time,
                                                      duration in hours,
                                                      estimate of the
                                                      volume of gas in
                                                      standard cubic
                                                      feet, the
                                                      concentration of
                                                      organic HAP in the
                                                      gas in parts per
                                                      million by volume
                                                      and the resulting
                                                      mass emissions of
                                                      organic HAP in
                                                      pounds that bypass
                                                      a control device.
                                                      For periods when
                                                      the flow indicator
                                                      is not operating,
                                                      report the start
                                                      date, start time,
                                                      and duration in
                                                      hours--PR.
------------------------------------------------------------------------
\a\ Regulatory citations are listed in brackets.
\b\ Monitor may be installed in the firebox or in the ductwork
  immediately downstream of the firebox before any substantial heat
  exchange is encountered.
\c\ ``Continuous records'' is defined in Sec.   63.111 of this subpart.
\d\ NCS = Notification of Compliance Status described in Sec.   63.152
  of this subpart.
\e\ The daily average is the average of all recorded parameter values
  for the operating day. If all recorded values during an operating day
  are within the range established in the NCS or operating permit, a
  statement to this effect can be recorded instead of the daily average.
\f\ The periodic reports shall include the duration of periods when
  monitoring data are not collected for each excursion as defined in
  Sec.   63.152(c)(2)(ii)(A) of this subpart.
\g\ PR = Periodic Reports described in Sec.   63.152 of this subpart.
\h\ Alternatively, these devices may comply with the organic monitoring
  device provisions listed at the end of this table under ``All Recovery
  Devices.''


0
96. Amend table 8 to subpart G by adding the entry for ``Ethylene 
oxide'' in alphabetical order to read as follows:

Table 8 to Subpart G of Part 63--Organic HAP's Subject to the Wastewater
               Provisions for Process Units at New Sources
------------------------------------------------------------------------
                       Chemical name                         CAS No. \a\
------------------------------------------------------------------------
 
                                * * * * *
Ethylene oxide.............................................        75218
 
                                * * * * *
------------------------------------------------------------------------


0
97. Revise table 13 to subpart G to read as follows:

            Table 13 to Subpart G of Part 63--Wastewater--Monitoring Requirements for Control Devices
----------------------------------------------------------------------------------------------------------------
                                         Monitoring equipment       Parameters to be
            Control device                     required                monitored                Frequency
----------------------------------------------------------------------------------------------------------------
All control devices..................  1. Flow indicator        1. Presence of flow      Hourly records of
                                        installed at all         diverted from the        whether the flow
                                        bypass lines to the      control device to the    indicator was
                                        atmosphere and           atmosphere or            operating and whether
                                        equipped with                                     a diversion was
                                        continuous recorder                               detected at any time
                                        \b\ or                                            during each hour.
                                       2. Valves sealed closed  2. Monthly inspections   Monthly.
                                        with car-seal or lock-   of sealed valves.
                                        and-key configuration.
Thermal Incinerator..................  Temperature monitoring   Firebox temperature....  Continuous.
                                        device installed in
                                        firebox or in ductwork
                                        immediately downstream
                                        of firebox \a\ and
                                        equipped with a
                                        continuous recorder
                                        \b\.

[[Page 43219]]

 
Catalytic Incinerator................  Temperature monitoring   1. Temperature upstream  Continuous.
                                        device installed in      of catalyst bed or
                                        gas stream immediately  2. Temperature
                                        before and after         difference across
                                        catalyst bed and         catalyst bed.
                                        equipped with a
                                        continuous recorder
                                        \b\.
Flare (if meeting the requirements of  Heat sensing device      Presence of a flame at   Hourly records of
 Sec.   63.139(c)(3)).                  installed at the pilot   the pilot light.         whether the monitor
                                        light and equipped                                was continuously
                                        with a continuous                                 operating and whether
                                        recorder \a\.                                     the pilot flame was
                                                                                          continuously present
                                                                                          during each hour.
Flare (if meeting the requirements of  The monitoring           The parameters are       The frequency is
 Sec.   63.108).                        equipment is specified   specified in Sec.        specified in Sec.
                                        in Sec.   63.108.        63.108.                  63.108.
Boiler or process heater <44           Temperature monitoring   Combustion temperature.  Continuous.
 megawatts and vent stream is not       device installed in
 mixed with the primary fuel.           firebox \a\ and
                                        equipped with
                                        continuous recorder
                                        \b\.
Condenser............................  Temperature monitoring   Condenser exit (product  Continuous.
                                        device installed at      side) temperature.
                                        condenser exit and
                                        equipped with
                                        continuous recorder
                                        \b\.
Carbon adsorber (regenerative,         Integrating              Total regeneration       For each regeneration
 regenerated onsite).                   regeneration stream      stream mass or           cycle, record the
                                        flow monitoring device   volumetric flow during   total regeneration
                                        having an accuracy of    carbon bed               stream mass or
                                        10           regeneration cycle(s).   volumetric flow.
                                        percent, and
                                       Carbon bed temperature   Temperature of carbon    For each regeneration
                                        monitoring device.       bed after regeneration   cycle and within 15
                                                                 [and within 15 minutes   minutes of completing
                                                                 of completing any        any cooling cycle,
                                                                 cooling cycle(s)].       record the carbon bed
                                                                                          temperature.
Carbon adsorber (Non-regenerative or   Organic compound         Organic compound         Daily or at intervals
 regenerative, regenerated offsite).    concentration            concentration of         no greater than 20
                                        monitoring device\c\.    adsorber exhaust.        percent of the design
                                                                                          carbon replacement
                                                                                          interval, whichever is
                                                                                          greater.
                                       The monitoring           The parameters are       The frequency is
                                        equipment is specified   specified in Sec.        specified in Sec.
                                        in Sec.   63.139(d)(5).  63.139(d)(5).            63.139(d)(5).
Organic monitoring device \d\........  Organic monitoring       Organic compound         Continuous.
                                        device installed at      concentration of
                                        the outlet of the        control device exhaust.
                                        control device.
Alternative monitoring parameters....  Other parameters may be
                                        monitored upon
                                        approval from the
                                        Administrator in
                                        accordance with the
                                        requirements in Sec.
                                        63.143(e)(3).
----------------------------------------------------------------------------------------------------------------
\a\ Monitor may be installed in the firebox or in the ductwork immediately downstream of the firebox before any
  substantial heat exchange is encountered.
\b\ ``Continuous recorder'' is defined in Sec.   63.111 of this subpart.
\c\ As an alternative to conducting this monitoring, an owner or operator may replace the carbon in the carbon
  adsorption system with fresh carbon at a regular predetermined time interval that is less than the carbon
  replacement interval that is determined by the maximum design flow rate and organic concentration in the gas
  stream vented to the carbon adsorption system. For each source as defined in Sec.   63.101, on and after July
  15, 2027, this footnote no longer applies.
\d\ A continuous organic monitoring device may be used in lieu of the requirements outlined for thermal
  incinerators, catalytic incinerators, boilers, process heaters, condensers, and carbon adsorbers.


0
98. Revise table 20 to subpart G to read as follows:

    Table 20 to Subpart G of Part 63--Wastewater--Periodic Reporting
Requirements for Control Devices Subject to Sec.   63.139 Used To Comply
                 With Sec.  Sec.   63.13 Through 63.139
------------------------------------------------------------------------
          Control device                   Reporting requirements
------------------------------------------------------------------------
(1) Thermal Incinerator. Report all daily average \a\ temperatures that
 are outside the range established in the NCS \b\ or operating permit
 and all operating days when insufficient monitoring data are
 collected.\c\
------------------------------------------------------------------------
(2) Catalytic Incinerator.........  (i) Report all daily average \a\
                                     upstream temperatures that are
                                     outside the range established in
                                     the NCS \b\ or operating permit.
                                    (ii) Report all daily average \a\
                                     temperature differences across the
                                     catalyst bed that are outside the
                                     range established in the NCS \b\ or
                                     operating permit.
                                    (iii) Report all operating days when
                                     insufficient monitoring data are
                                     collected.\c\
(3) Boiler or Process Heater with   Report all daily average \a\ firebox
 a design heat input capacity less   temperatures that are outside the
 than 44 megawatts and vent stream   range established in the NCS \b\ or
 is not mixed with the primary       operating permit and all operating
 fuel.                               days when insufficient monitoring
                                     data are collected.\c\
(4a) Flare (if meeting the          Report the duration of all periods
 requirements of Sec.                when all pilot flames are absent.
 63.139(c)(3)).
(4b) Flare (if meeting the          The reporting requirements are
 requirements of Sec.   63.108).     specified in Sec.   63.108(l) of
                                     subpart F of this part.
(5) Condenser.....................  Report all daily average \a\ exit
                                     temperatures that are outside the
                                     range established in the NCS \b\ or
                                     operating permit and all operating
                                     days when insufficient monitoring
                                     data are collected.\c\
(6) Carbon Adsorber (Regenerative)  (i) Report all carbon bed
                                     regeneration cycles when the total
                                     regeneration stream mass or
                                     volumetric flow is outside the
                                     range established in the NCS \b\ or
                                     operating permit.
                                    (ii) Report all carbon bed
                                     regeneration cycles during which
                                     the temperature of the carbon bed
                                     after regeneration is outside the
                                     range established in the NCS \b\ or
                                     operating permit.

[[Page 43220]]

 
                                    (iii) Report all operating days when
                                     insufficient monitoring data are
                                     collected\c\.
                                    (iv) For each regenerative adsorber
                                     that is regenerated offsite subject
                                     to the requirements in Sec.
                                     63.139(d)(5) report the date of
                                     each instance when breakthrough, as
                                     defined in Sec.   63.101, is
                                     detected between the first and
                                     second adsorber and the adsorber is
                                     not replaced according to Sec.
                                     63.139(d)(5)(iii)(A).
(7) Carbon Adsorber (Non-           (i) Report all operating days when
 Regenerative).                      inspections not done according to
                                     the schedule developed as specified
                                     in table 13 of this subpart.
                                    (ii) Report all operating days when
                                     carbon has not been replaced at the
                                     frequency specified in table 13 of
                                     this subpart.
                                    (iii) For each nonregenerative
                                     adsorber subject to the
                                     requirements in Sec.
                                     63.139(d)(5), report the date of
                                     each instance when breakthrough, as
                                     defined in Sec.   63.101, is
                                     detected between the first and
                                     second adsorber and the adsorber is
                                     not replaced according to Sec.
                                     63.139(d)(5)(iii)(A).
(8) All Control Devices...........  (i) Report the times and durations
                                     of all periods when the vent stream
                                     is diverted through a bypass line
                                     or the monitor is not operating, or
                                    (ii) Report all monthly inspections
                                     that show the valves are moved to
                                     the diverting position or the seal
                                     has been changed.
                                    (iii) For each source as defined in
                                     Sec.   63.101, beginning no later
                                     than the compliance dates specified
                                     in Sec.   63.100(k)(10), report the
                                     start date, start time, duration in
                                     hours, estimate of the volume of
                                     gas in standard cubic feet, the
                                     concentration of organic HAP in the
                                     gas in parts per million by volume
                                     and the resulting mass emissions of
                                     organic HAP in pounds that bypass a
                                     control device. For periods when
                                     the flow indicator is not
                                     operating, report the start date,
                                     start time, and duration in hours.
(9) Thermal Incinerator, Catalytic  (i) Report all daily average \a\
 Incinerator, Boiler, Process        concentration levels or readings
 Heater, Condenser, or Carbon        that are outside the range
 Adsorber using a continuous         established in the NCS or operating
 organic monitoring device as        permit.\c\
 specified in Sec.   63.143(e)(2).  (ii) Report all operating days when
                                     insufficient monitoring data are
                                     collected.\c\
------------------------------------------------------------------------
\a\ The daily average is the average of all values recorded during the
  operating day, as specified in Sec.   63.147(d).
\b\ NCS = Notification of Compliance Status described in Sec.   63.152.
\c\ The periodic reports shall include the duration of periods when
  monitoring data are not collected for each excursion as defined in
  Sec.   63.152(c)(2)(ii)(A).


0
99. Add table 38 to subpart G to read as follows:

       Table 38 to Subpart G of Part 63--Toxic Equivalency Factors
------------------------------------------------------------------------
                                                      Toxic equivalency
             Dioxin and furan congener                     factor
------------------------------------------------------------------------
1,2,3,7,8-pentachlorodibenzo-p-dioxin.............                     1
1,2,3,4,7,8-hexachlorodibenzo-p-dioxin............                   0.1
1,2,3,7,8,9-hexachlorodibenzo-p-dioxin............                   0.1
1,2,3,6,7,8-hexachlorodibenzo-p-dioxin............                   0.1
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin.........                  0.01
octachlorodibenzo-p-dioxin........................                0.0003
2,3,7,8-tetrachlorodibenzofuran...................                   0.1
2,3,4,7,8-pentachlorodibenzofuran.................                   0.3
1,2,3,7,8-pentachlorodibenzofuran.................                  0.03
1,2,3,4,7,8-hexachlorodibenzofuran................                   0.1
1,2,3,6,7,8-hexachlorodibenzofuran................                   0.1
1,2,3,7,8,9-hexachlorodibenzofuran................                   0.1
2,3,4,6,7,8-hexachlorodibenzofuran................                   0.1
1,2,3,4,6,7,8-heptachlorodibenzofuran.............                  0.01
1,2,3,4,7,8,9-heptachlorodibenzofuran.............                  0.01
Octachlorodibenzofuran............................                0.0003
------------------------------------------------------------------------


0
100. Revise the heading to subpart H to read as follows:

Subpart H--National Emission Standards for Hazardous Air Pollutants 
for Equipment Leaks and Fenceline Monitoring for All Emission 
Sources

0
101. Amend Sec.  63.160 by:
0
a. Revising paragraph (b)(1);
0
b. Revising and republishing paragraph (c); and
0
c. Revising paragraphs (g) introductory text and (g)(1).
    The revisions and republication read as follows:

[[Page 43221]]

Sec.  63.160  Applicability and designation of source.

* * * * *
    (b) * * *
    (1) Part 60 of this chapter will be required to comply only with 
the provisions of this subpart, except as specified in Sec. Sec.  
60.480a(e)(2)(i) and 60.480b(e)(2)(i) of this chapter.
* * * * *
    (c) If a process unit subject to the provisions of this subpart has 
equipment to which this subpart does not apply, but which is subject to 
a standard identified in paragraph (c)(1), (2), or (3) of this section, 
the owner or operator may elect to apply this subpart to all such 
equipment in the process unit. If the owner or operator elects this 
method of compliance, all VOC in such equipment shall be considered, 
for purposes of applicability and compliance with this subpart, as if 
it were organic hazardous air pollutant (HAP). Compliance with the 
provisions of this subpart, in the manner described in this paragraph, 
shall be deemed to constitute compliance with the standard identified 
in paragraph (c)(1), (2), or (3) of this section.
    (1) Part 60, subpart VV, VVa, VVb, GGG, or KKK, of this chapter, 
except as specified in Sec. Sec.  60.480a(e)(2)(i) and 60.480b(e)(2)(i) 
of this chapter;
    (2) Part 61, subpart F or J of this chapter; or
    (3) Part 264, subpart BB of this chapter or part 265, subpart BB of 
this chapter.
* * * * *
    (g) Alternative means of compliance--For each source as defined in 
Sec.  63.101, and for each source as defined in Sec.  63.191, on and 
after July 15, 2027, this paragraph no longer applies.
    (1) Option to comply with 40 CFR part 65. Owners or operators of 
CMPU that are subject to Sec.  63.100 may choose to comply with the 
provisions of 40 CFR part 65 for all Group 1 and Group 2 process vents, 
Group 1 storage vessels, Group 1 transfer operations, and equipment 
that are subject to Sec.  63.100, that are part of the CMPU. Other 
provisions applying to an owner or operator who chooses to comply with 
40 CFR part 65 are provided in 40 CFR 65.1.
* * * * *

0
102. Revise Sec.  63.161 to read as follows:


Sec.  63.161  Definitions.

    All terms used in this subpart shall have the meaning given them in 
the Act and in subpart F of this part, except as provided in any 
subpart that references this subpart.

0
103. Amend Sec.  63.163 by:
0
a. Adding paragraph (a)(1)(iii);
0
b. Revising paragraph (b)(2) introductory text and adding paragraph 
(b)(2)(iv);
0
c. Revising paragraph (c)(3) and adding paragraph (c)(4);
0
d. Revising paragraph (e) introductory text and adding paragraph 
(e)(7); and
0
e. Revising paragraphs (g), (j) introductory text and (j)(1).
    The revisions and additions read as follows:


Sec.  63.163  Standards: Pumps in light liquid service.

    (a) * * *
    (1) * * *
    (iii) For each source as defined in Sec.  63.101, and for each 
source as defined in Sec.  63.191, beginning no later than the 
compliance dates specified in Sec.  63.100(k)(11), for each pump in 
ethylene oxide service, as defined in Sec.  63.101, that is added to a 
CMPU, and for each pump in ethylene oxide service, that replaces a pump 
in ethylene oxide service, owners and operators must initially monitor 
for leaks within 5 days after initial startup of the equipment.
* * * * *
    (b) * * *
    (2) Except as specified in paragraph (b)(2)(iv) of this section, 
the instrument reading, as determined by the method as specified in 
Sec.  63.180(b), that defines a leak in each phase of the standard is:
* * * * *
    (iv) For each source as defined in Sec.  63.101, and for each 
source as defined in Sec.  63.191, beginning no later than the 
compliance dates specified in Sec.  63.100(k)(11), for pumps in 
ethylene oxide service, as defined in Sec.  63.101, the instrument 
reading that defines a leak for pumps is 500 parts per million or 
greater.
* * * * *
    (c) * * *
    (3) Except as specified in paragraph (c)(4) of this section, for 
pumps in Phase III to which a 1,000 parts per million leak definition 
applies, repair is not required unless an instrument reading of 2,000 
parts per million or greater is detected.
    (4) For each source as defined in Sec.  63.101, and for each source 
as defined in Sec.  63.191, beginning no later than the compliance 
dates specified in Sec.  63.100(k)(11), for pumps in ethylene oxide 
service, as defined in Sec.  63.101, paragraph (c)(3) of this section 
is not applicable.
* * * * *
    (e) Except as specified in paragraph (e)(7) of this section, each 
pump equipped with a dual mechanical seal system that includes a 
barrier fluid system is exempt from the requirements of paragraphs (a) 
through (d) of this section, provided the following requirements are 
met:
* * * * *
    (7) For each source as defined in Sec.  63.101, and for each source 
as defined in Sec.  63.191, beginning no later than the compliance 
dates specified in Sec.  63.100(k)(11), for pumps in ethylene oxide 
service, as defined in Sec.  63.101, paragraph (e) of this section is 
not applicable.
* * * * *
    (g) Any pump that is routed to a process or fuel gas system or 
equipped with a closed vent system capable of capturing and 
transporting leakage from the pump to a control device meeting the 
requirements of Sec.  63.172 is exempt from the requirements of 
paragraphs (a)(1)(iii), and (b) through (e) of this section.
* * * * *
    (j) Any pump that is designated, as described in Sec.  
63.181(b)(7)(i), as an unsafe-to-monitor pump is exempt from the 
requirements of paragraphs (a)(1)(iii), and (b) through (e) of this 
section if:
    (1) The owner or operator of the pump determines that the pump is 
unsafe to monitor because monitoring personnel would be exposed to an 
immediate danger as a consequence of complying with paragraphs 
(a)(1)(iii), and (b) through (d) of this section; and
* * * * *

0
104. Amend Sec.  63.164 by revising paragraph (h) to read as follows:


Sec.  63.164  Standards: Compressors.

* * * * *
    (h) A compressor is exempt from the requirements of paragraphs (a) 
through (g) of this section if it is equipped with a system to capture 
and transport leakage from the compressor drive shaft seal to a process 
or a fuel gas system or to a closed vent system that captures and 
transports leakage from the compressor to a control device meeting the 
requirements of Sec.  63.172 of this subpart.
* * * * *

0
105. Revise and republish Sec.  63.165 to read as follows:


Sec.  63.165  Standards: Pressure relief devices in gas/vapor service 
or light liquid service.

    (a) Except during pressure releases, each pressure relief device in 
gas/vapor service shall be operated with an instrument reading of less 
than 500 parts per million above background

[[Page 43222]]

except as provided in paragraph (b) of this section, as measured by the 
method specified in Sec.  63.180(c). For each source as defined in 
Sec.  63.101, and for each source as defined in Sec.  63.191, beginning 
no later than the compliance dates specified in Sec.  63.100(k)(10), 
this paragraph (a) no longer applies and instead the owner or operator 
must comply with paragraph (e) of this section.
    (b) Except as specified in paragraph (e) of this section, comply 
with paragraphs (b)(1) and (b)(2) of this section.
    (1) After each pressure release, the pressure relief device shall 
be returned to a condition indicated by an instrument reading of less 
than 500 parts per million above background, as soon as practicable, 
but no later than 5 calendar days after each pressure release, except 
as provided in Sec.  63.171.
    (2) No later than 5 calendar days after the pressure release and 
being returned to organic HAP service, the pressure relief device shall 
be monitored to confirm the condition indicated by an instrument 
reading of less than 500 parts per million above background, as 
measured by the method specified in Sec.  63.180(c).
    (c) Except as specified in paragraph (e) of this section, any 
pressure relief device that is routed to a process or fuel gas system 
or equipped with a closed-vent system capable of capturing and 
transporting leakage from the pressure relief device to a control 
device as described in Sec.  63.172 is exempt from the requirements of 
paragraphs (a) and (b) of this section.
    (d) Except as specified in paragraph (e) of this section, comply 
with paragraphs (d)(1) and (d)(2) of this section.
    (1) Any pressure relief device that is equipped with a rupture disk 
upstream of the pressure relief device is exempt from the requirements 
of paragraphs (a) and (b) of this section, provided the owner or 
operator complies with the requirements in paragraph (d)(2) of this 
section.
    (2) After each pressure release, a rupture disk shall be installed 
upstream of the pressure relief device as soon as practicable, but no 
later than 5 calendar days after each pressure release, except as 
provided in Sec.  63.171.
    (e) For each source as defined in Sec.  63.101, and for each source 
as defined in Sec.  63.191, beginning no later than the compliance 
dates specified in Sec.  63.100(k)(10), except as specified in 
paragraph (e)(4) of this section, owners and operators must comply with 
the requirements specified in paragraphs (e)(1) and (2) of this section 
for pressure relief devices, such as relief valves or rupture disks, in 
organic HAP gas or vapor service instead of the pressure relief device 
requirements of paragraph (a) through (d) of this section. Except as 
specified in paragraphs (e)(4) and (5) of this section, owners and 
operators must also comply with the requirements specified in 
paragraphs (e)(3), (6), (7), and (8) of this section for all pressure 
relief devices in organic HAP service.
    (1) Operating requirements. Except during a pressure release, 
operate each pressure relief device in organic HAP gas or vapor service 
with an instrument reading of less than 500 ppm above background as 
measured by the method in Sec.  63.180(c).
    (2) Pressure release requirements. For pressure relief devices in 
organic HAP gas or vapor service, owners and operators must comply with 
the applicable requirements paragraphs (e)(2)(i) through (iii) of this 
section following a pressure release.
    (i) If the pressure relief device does not consist of or include a 
rupture disk, conduct instrument monitoring, as specified in Sec.  
63.180(c), no later than 5 calendar days after the pressure relief 
device returns to organic HAP gas or vapor service following a pressure 
release to verify that the pressure relief device is operating with an 
instrument reading of less than 500 ppm.
    (ii) If the pressure relief device includes a rupture disk, either 
comply with the requirements in paragraph (e)(2)(i) of this section 
(and do not replace the rupture disk) or install a replacement disk as 
soon as practicable after a pressure release, but no later than 5 
calendar days after the pressure release.
    (iii) If the pressure relief device consists only of a rupture 
disk, install a replacement disk as soon as practicable after a 
pressure release, but no later than 5 calendar days after the pressure 
release. Owners and operators must not initiate startup of the 
equipment served by the rupture disk until the rupture disc is 
replaced.
    (3) Pressure release management. Except as specified in paragraphs 
(e)(4) and (5) of this section, owners and operators must comply with 
the requirements specified in paragraphs (e)(3)(i) through (v) of this 
section for all pressure relief devices in organic HAP service.
    (i) Owners and operators must equip each affected pressure relief 
device with a device(s) or use a monitoring system that is capable of:
    (A) Identifying the pressure release;
    (B) Recording the time and duration of each pressure release; and
    (C) Notifying operators immediately that a pressure release is 
occurring. The device or monitoring system must be either specific to 
the pressure relief device itself or must be associated with the 
process system or piping, sufficient to indicate a pressure release to 
the atmosphere. Examples of these types of devices and systems include, 
but are not limited to, a rupture disk indicator, magnetic sensor, 
motion detector on the pressure relief valve stem, flow monitor, or 
pressure monitor.
    (ii) Owners and operators must apply at least three redundant 
prevention measures to each affected pressure relief device and 
document these measures. Examples of prevention measures include:
    (A) Flow, temperature, liquid level and pressure indicators with 
deadman switches, monitors, or automatic actuators. Independent, non-
duplicative systems within this category count as separate redundant 
prevention measures.
    (B) Documented routine inspection and maintenance programs and/or 
operator training (maintenance programs and operator training may count 
as only one redundant prevention measure).
    (C) Inherently safer designs or safety instrumentation systems.
    (D) Deluge systems.
    (E) Staged relief system where the initial pressure relief device 
(with lower set release pressure) discharges to a flare or other closed 
vent system and control device.
    (iii) If any affected pressure relief device releases to atmosphere 
as a result of a pressure release event, owners and operators must 
perform root cause analysis and corrective action analysis according to 
the requirement in paragraph (e)(6) of this section and implement 
corrective actions according to the requirements in paragraph (e)(7) of 
this section. Owners and operators must also calculate the quantity of 
organic HAP released during each pressure release event and report this 
quantity as required in Sec.  63.182(d)(2)(xviii). Calculations may be 
based on data from the pressure relief device monitoring alone or in 
combination with process parameter monitoring data and process 
knowledge.
    (iv) Owners and operators must determine the total number of 
release events that occurred during the calendar year for each affected 
pressure relief device separately.
    (v) Except for pressure relief devices described in paragraphs 
(e)(4) and (5) of this section, the following release events from an 
affected pressure relief device

[[Page 43223]]

are a violation of the pressure release management work practice 
standards.
    (A) Except as specified in paragraph (e)(3)(v)(D) of this section, 
any release event for which the root cause of the event was determined 
to be operator error or poor maintenance.
    (B) Except as specified in paragraph (e)(3)(v)(D) of this section, 
a second release event from a single pressure relief device in a 3 
calendar year period for the same root cause for the same equipment.
    (C) Except as specified in paragraph (e)(3)(v)(D) of this section, 
a third release event from a single pressure relief device in a 3 
calendar year period for any reason.
    (D) Paragraphs (e)(3)(v)(A) through (e)(3)(v)(C) of this section do 
not apply to pressure relief devices in ethylene oxide service, as 
defined in Sec.  63.101; instead, any release event from an affected 
pressure relief device in ethylene oxide service is a violation of the 
pressure release management work practice standards.
    (4) Pressure relief devices routed to a control device, process, 
fuel gas system, or drain system. (i) If all releases and potential 
leaks from a pressure relief device are routed through a closed vent 
system to a control device, back into the process, to the fuel gas 
system, or to a drain system, then owners and operators are not 
required to comply with paragraph (e)(1), (2), or (3) of this section.
    (ii) Both the closed vent system and control device (if applicable) 
referenced in paragraph (e)(4)(i) of this section must meet the 
applicable requirements specified in Sec.  63.172.
    (iii) The drain system (if applicable) referenced in paragraph 
(e)(4)(i) of this section must meet the applicable requirements 
specified in Sec.  63.136(e).
    (5) Pressure relief devices exempted from pressure release 
management requirements. The following types of pressure relief devices 
are not subject to the pressure release management requirements in 
paragraph (e)(3) of this section.
    (i) Pressure relief devices in heavy liquid service, as defined in 
Sec.  63.161.
    (ii) Thermal expansion relief valves.
    (iii) Pressure relief devices on mobile equipment.
    (iv) Pilot-operated pressure relief devices where the primary 
release valve is routed through a closed vent system to a control 
device or back into the process, to the fuel gas system, or to a drain 
system.
    (v) Balanced bellows pressure relief devices where the primary 
release valve is routed through a closed vent system to a control 
device or back into the process, to the fuel gas system, or to a drain 
system.
    (6) Root cause analysis and corrective action analysis. A root 
cause analysis and corrective action analysis must be completed as soon 
as possible, but no later than 45 days after a release event. Special 
circumstances affecting the number of root cause analyses and/or 
corrective action analyses are provided in paragraphs (e)(6)(i) through 
(iii) of this section.
    (i) Owners and operators may conduct a single root cause analysis 
and corrective action analysis for a single emergency event that causes 
two or more pressure relief devices installed on the same equipment to 
release.
    (ii) [Reserved]
    (iii) Except as provided in paragraph (e)(6)(i) of this section, if 
more than one pressure relief device has a release during the same time 
period, an initial root cause analysis must be conducted separately for 
each pressure relief device that had a release. If the initial root 
cause analysis indicates that the release events have the same root 
cause(s), the initially separate root cause analyses may be recorded as 
a single root cause analysis and a single corrective action analysis 
may be conducted.
    (7) Corrective action implementation. Owners and operators must 
conduct a root cause analysis and corrective action analysis as 
specified in paragraphs (e)(3)(iii) and (e)(6) of this section, and 
owners and operators must implement the corrective action(s) identified 
in the corrective action analysis in accordance with the applicable 
requirements in paragraphs (e)(7)(i) through (iii) of this section.
    (i) All corrective action(s) must be implemented within 45 days of 
the event for which the root cause and corrective action analyses were 
required or as soon thereafter as practicable. If the owner or operator 
concludes that no corrective action should be implemented, the owner or 
operator must record and explain the basis for that conclusion no later 
than 45 days following the event.
    (ii) For corrective actions that cannot be fully implemented within 
45 days following the event for which the root cause and corrective 
action analyses were required, owners and operators must develop an 
implementation schedule to complete the corrective action(s) as soon as 
practicable.
    (iii) No later than 45 days following the event for which a root 
cause and corrective action analyses were required, owners and 
operators must record the corrective action(s) completed to date, and, 
for action(s) not already completed, a schedule for implementation, 
including proposed commencement and completion dates.
    (8) Flowing pilot-operated pressure relief devices. For affected 
sources that commenced construction or reconstruction on or before 
April 25, 2023, owners and operators are prohibited from installing a 
flowing pilot-operated pressure relief device or replacing any pressure 
relief device with a flowing pilot-operated pressure relief device 
after July 15, 2027. For affected sources that commenced construction 
or reconstruction after April 25, 2023, owners and operators are 
prohibited from installing and operating flowing pilot-operated 
pressure relief devices. For purpose of compliance with this paragraph, 
a flowing pilot-operated pressure relief device means the type of 
pilot-operated pressure relief device where the pilot discharge vent 
continuously releases emissions to the atmosphere when the pressure 
relief device is actuated.

0
106. Amend Sec.  63.168 by:
0
a. Revising paragraph (b)(2) introductory text and adding paragraph 
(b)(2)(iv); and
0
b. Revising paragraph (d) introductory text and and adding paragraph 
(d)(5).
    The revisions and additions read as follows:


Sec.  63.168  Standards: Valves in gas/vapor service and in light 
liquid service.

* * * * *
    (b) * * *
    (2) Except as specified in paragraph (b)(2)(iv) of this section, 
the instrument reading that defines a leak in each phase of the 
standard is:
* * * * *
    (iv) For each source as defined in Sec.  63.101, and for each 
source as defined in Sec.  63.191, beginning no later than the 
compliance dates specified in Sec.  63.100(k)(11), for valves in 
ethylene oxide service, as defined in Sec.  63.101, that are either in 
gas service or in light liquid service the instrument reading that 
defines a leak is 100 parts per million or greater.
* * * * *
    (d) Except as specified in paragraph (d)(5) of this section, in 
Phase III, the owner or
* * * * *
    (5) For each source as defined in Sec.  63.101, and for each source 
as defined in Sec.  63.191, beginning no later than the compliance 
dates specified in Sec.  63.100(k)(11), for valves in ethylene oxide 
service, as defined in Sec.  63.101, that are either in gas service or 
in light

[[Page 43224]]

liquid service the monitoring period is once per month.
* * * * *

0
107. Revise Sec.  63.170 to read as follows:


Sec.  63.170  Standards: Surge control vessels and bottoms receivers.

    (a) Except as specified in paragraph (b) of this section, each 
surge control vessel or bottoms receiver that is not routed back to the 
process and that meets the conditions specified in table 2 or table 3 
of this subpart shall be equipped with a closed-vent system that routes 
the organic vapors vented from the surge control vessel or bottoms 
receiver back to the process or to a control device that complies with 
the requirements in Sec.  63.172, except as provided in Sec.  
63.162(b), or comply with the requirements of Sec.  63.119(b) or (c).
    (b) For each source as defined in Sec.  63.101, and for each source 
as defined in Sec.  63.191, beginning no later than the compliance 
dates specified in Sec.  63.100(k)(10), paragraph (a) of this section 
no longer applies. Instead, each surge control vessel and bottoms 
receiver that is not routed back to the process and emits greater than 
or equal to 1.0 lb/hr of total organic HAP must be equipped with a 
closed-vent system that routes the organic vapors vented from the surge 
control vessel or bottoms receiver back to the process or to a control 
device that complies with the requirements in Sec.  63.172, except as 
provided in Sec.  63.162(b), or comply with the requirements of Sec.  
63.113(a)(1) or (a)(2).

0
108. Amend Sec.  63.171 by revising paragraphs (a), (c) introductory 
text, (d) introductory text and (e), and adding paragraph (f) to read 
as follows:


Sec.  63.171  Standards: Delay of repair.

    (a) Except as specified in paragraph (f) of this section, delay of 
repair of equipment for which leaks have been detected is allowed if 
repair within 15 days is technically infeasible without a process unit 
shutdown. Repair of this equipment shall occur by the end of the next 
process unit shutdown.
* * * * *
    (c) Except as specified in paragraph (f) of this section, delay of 
repair for valves, connectors, and agitators is also allowed if:
* * * * *
    (d) Except as specified in paragraph (f) of this section, delay of 
repair for pumps is also allowed if:
* * * * *
    (e) Except as specified in paragraph (f) of this section, delay of 
repair beyond a process unit shutdown will be allowed for a valve if 
valve assembly replacement is necessary during the process unit 
shutdown, valve assembly supplies have been depleted, and valve 
assembly supplies had been sufficiently stocked before the supplies 
were depleted. Delay of repair beyond the second process unit shutdown 
will not be allowed unless the third process unit shutdown occurs 
sooner than 6 months after the first process unit shutdown.
    (f) For each source as defined in Sec.  63.101, and for each source 
as defined in Sec.  63.191, beginning no later than the compliance 
dates specified in Sec.  63.100(k)(11), delay of repair is not allowed 
for light liquid pumps in ethylene oxide service, gas/vapor and light 
liquid valves in ethylene oxide service, and connectors in ethylene 
oxide service.

0
109. Amend Sec.  63.172 by revising paragraphs (b), (d), (j) 
introductory text and (j)(3), and adding paragraph (j)(4) to read as 
follows:


Sec.  63.172  Standards: Closed-vent systems and control devices.

* * * * *
    (b) Recovery or recapture devices (e.g., condensers and absorbers) 
shall be designed and operated to recover the organic hazardous air 
pollutant emissions or volatile organic compounds emissions vented to 
them with an efficiency of 95 percent or greater, or to an exit 
concentration of 20 parts per million by volume, whichever is less 
stringent. The 20 parts per million by volume performance standard is 
not applicable to the provisions of Sec.  63.179.
* * * * *
    (d) Except as specified in paragraph (a) of Sec.  63.108, flares 
used to comply with this subpart shall comply with the requirements of 
Sec.  63.11(b).
* * * * *
    (j) For each closed-vent system that contains bypass lines that 
could divert a vent stream away from the control device and to the 
atmosphere, the owner or operator shall comply with the provisions of 
either paragraphs (j)(1) or (j)(2), and (j)(4) of this section, except 
as provided in paragraph (j)(3) of this section.
* * * * *
    (3) Except as specified in paragraph (j)(4) of this section, 
equipment such as low leg drains, high point bleeds, analyzer vents, 
open-ended valves or lines, and pressure relief valves needed for 
safety purposes are not subject to this paragraph.
    (4) For each source as defined in Sec.  63.101, and for each source 
as defined in Sec.  63.191, beginning no later than the compliance 
dates specified in Sec.  63.100(k)(10):
    (i) The use of a bypass line at any time on a closed vent system 
(used to comply with the provisions of this subpart) to divert 
emissions to the atmosphere or to a control device not meeting the 
requirements specified in this subpart is an emissions standards 
violation.
    (ii) Paragraph (j)(3) of this section does not apply. Instead, the 
exemptions specified in paragraph (j)(4)(ii)(A) and (j)(4)(ii)(B) of 
this section apply.
    (A) Except for pressure relief devices subject to Sec.  
63.165(e)(4), equipment such as low leg drains and equipment subject to 
the requirements specified in subpart H of this part are not subject to 
this paragraph (j) of this section.
    (B) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in 40 CFR 60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as 40 CFR 60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (j) of this section.
* * * * *

0
110. Amend Sec.  63.173 by revising paragraph (f) as follows:


Sec.  63.173  Standards: Agitators in gas/vapor service and in light 
liquid service.

* * * * *
    (f) Any agitator if it is equipped with a system to capture and 
transport leakage from the agitator to a process or a fuel gas system 
or to a closed vent system that captures and transports leakage from 
the agitator to a control device meeting the requirements of Sec.  
63.172 is exempt from the requirements of paragraphs (a) through (c) of 
the section.
* * * * *

0
111. Amend Sec.  63.174 by:
0
a. Revising paragraph (a)(2) and adding (a)(3);
0
b. Revising paragraphs (b) introductory text, (b)(3) introductory text, 
and adding paragraphs (b)(3)(vi) and (b)(5); and
0
c. Revising paragraphs (g) introductory text and (g)(3).
    The revisions and additions read as follows:


Sec.  63.174  Standards: Connectors in gas/vapor service and in light 
liquid service.

    (a) * * *
    (2) Except as specified in paragraph (a)(3) of this section, if an 
instrument reading greater than or equal to 500 parts per million is 
measured, a leak is detected.
    (3) For each source as defined in Sec.  63.101, and for each source 
as defined

[[Page 43225]]

in Sec.  63.191, beginning no later than the compliance dates specified 
in Sec.  63.100(k)(11), for connectors in ethylene oxide service, as 
defined in Sec.  63.101, the instrument reading that defines a leak for 
connectors is 100 parts per million or greater.
    (b) The owner or operator shall monitor for leaks at the intervals 
specified in either paragraph (b)(1) or (b)(2) of this section and in 
paragraphs (b)(3) through (b)(5) of this section.
* * * * *
    (3) After conducting the initial survey required in paragraph 
(b)(1) or (b)(2) of this section, the owner or operator shall perform 
all subsequent monitoring of connectors at the frequencies specified in 
paragraphs (b)(3)(i) through (b)(3)(v) of this section, except as 
provided in paragraphs (b)(3)(vi) and (c)(2) of this section:
* * * * *
    (vi) For each source as defined in Sec.  63.101, and for each 
source as defined in Sec.  63.191, beginning no later than the 
compliance dates specified in Sec.  63.100(k)(11), for connectors in 
ethylene oxide service, as defined in Sec.  63.101, the monitoring 
period is once every month and paragraph (c)(2) of this section is not 
applicable.
* * * * *
    (5) For each source as defined in Sec.  63.101, and for each source 
as defined in Sec.  63.191, beginning no later than the compliance 
dates specified in Sec.  63.100(k)(11), for each connector in ethylene 
oxide service, as defined in Sec.  63.101, that is added to a CMPU, and 
for each connector in ethylene oxide service that replaces a connector 
in ethylene oxide service, owners and operators must initially monitor 
for leaks within 5 days after initial startup of the equipment.
* * * * *
    (g) Except as specified in paragraph (g)(3) of this section, any 
connector that is designated, as described in Sec.  63.181(b)(7)(iii), 
as an unsafe-to-repair connector is exempt from the requirements of 
paragraphs (a), (d), and (e) of this section if:
* * * * *
    (3) For each source as defined in Sec.  63.101, and for each source 
as defined in Sec.  63.191, beginning no later than the compliance 
dates specified in Sec.  63.100(k)(11), for connectors in ethylene 
oxide service, as defined in Sec.  63.101, paragraph (g) of this 
section is no longer applicable.
* * * * *

0
112. Amend Sec.  63.180 by revising paragraphs (c) introductory text, 
(d)(1) and (e) introductory text to read as follows:


Sec.  63.180  Test methods and procedures.

* * * * *
    (c) When equipment is monitored for compliance as required in 
Sec. Sec.  63.164(i), 63.165(a) or (e)(1), and 63.172(f) or when 
equipment subject to a leak definition of 500 ppm is monitored for 
leaks as required by this subpart, the owner or operator may elect to 
adjust or not to adjust the instrument readings for background. If an 
owner or operator elects to not adjust instrument readings for 
background, the owner or operator shall monitor the equipment according 
to the procedures specified in paragraphs (b)(1) through (4) of this 
section. In such case, all instrument readings shall be compared 
directly to the applicable leak definition to determine whether there 
is a leak. If an owner or operator elects to adjust instrument readings 
for background, the owner or operator shall monitor the equipment 
according to the procedures specified in paragraphs (c)(1) through 
(c)(4) of this section.
* * * * *
    (d)(1) Each piece of equipment within a process unit that can 
reasonably be expected to contain equipment in organic HAP service is 
presumed to be in organic HAP service unless an owner or operator 
demonstrates that the piece of equipment is not in organic HAP service. 
For a piece of equipment to be considered not in organic HAP service, 
it must be determined that the percent organic HAP content can be 
reasonably expected not to exceed 5 percent by weight on an annual 
average basis. For purposes of determining the percent organic HAP 
content of the process fluid that is contained in or contacts 
equipment, Method 18 of 40 CFR part 60, appendix A shall be used. ASTM 
D6420-18 (incorporated by reference, see Sec.  [thinsp]63.14) may also 
be used in lieu of Method 18, if the target compounds are all known and 
are all listed in Section 1.1 of ASTM D6420-18 as measurable; ASTM 
D6420-18 must not be used for methane and ethane; and ASTM D6420-18 may 
not be used as a total VOC method.
* * * * *
    (e) When a flare is used to comply with Sec.  63.172(d), the owner 
or operator shall comply with paragraphs (e)(1) through (3) of this 
section, except as specified in paragraph (a) of Sec.  63.108. The 
owner or operator is not required to conduct a performance test to 
determine percent emission reduction or outlet organic HAP or TOC 
concentration.
* * * * *

0
113. Amend Sec.  63.181 by:
0
a. Revising paragraphs (b)(2)(i) and (b)(3), and adding paragraphs 
(b)(11) and (12);
0
b. Revising paragraphs (d)(5)(i), (g)(1)(iii), (g)(2)(i) and (g)(3) 
introductory text; and
0
c. Adding paragraphs (g)(3)(iii) and (l).
    The revisions and additions read as follows:


Sec.  63.181  Recordkeeping requirements.

* * * * *
    (b) * * *
    (2)(i) A list of identification numbers for equipment that the 
owner or operator elects to equip with a closed-vent system and control 
device, under the provisions of Sec.  63.163(g), Sec.  63.164(h), Sec.  
63.165(c) or (e)(4), or Sec.  63.173(f), as applicable.
* * * * *
    (3)(i) A list of identification numbers for pressure relief devices 
subject to the provisions in Sec.  63.165(a) or (e)(1), as applicable.
    (ii) A list of identification numbers for pressure relief devices 
equipped with rupture disks, under the provisions of Sec.  63.165(d), 
(e)(2)(ii), or (e)(2)(iii), as applicable.
* * * * *
    (11) For each pressure relief device subject to the pressure 
release management work practice standards in Sec.  63.165(e), owners 
and operators must keep the records specified in paragraphs (b)(11)(i) 
through (iii) of this section in addition to the records specified in 
paragraph (f) of this section.
    (i) Records of the prevention measures implemented as required in 
Sec.  63.165(e)(3)(ii).
    (ii) Records of the number of releases during each calendar year. 
Keep these records for the current calendar year and the past 5 
calendar years.
    (iii) For each release to the atmosphere, owners and operators must 
keep the records specified in paragraphs (b)(11)(iii)(A) through (D) of 
this section.
    (A) The start and end time and date of each pressure release to the 
atmosphere.
    (B) Records of any data, assumptions, and calculations used to 
estimate of the mass quantity of each organic HAP released during the 
event.
    (C) Records of the root cause analysis and corrective action 
analysis conducted as required in Sec.  63.165(e)(3)(iii), including an 
identification of the affected facility, a statement noting whether the 
event resulted from the same root cause(s) identified in a previous 
analysis and either a description of the recommended corrective 
action(s) or an explanation of why corrective action is not necessary 
under Sec.  63.165(e)(7)(i).

[[Page 43226]]

    (D) For any corrective action analysis for which implementation of 
corrective actions are required in Sec.  63.165(e)(7), a description of 
the corrective action(s) completed within the first 45 days following 
the discharge and, for action(s) not already completed, a schedule for 
implementation, including proposed commencement and completion dates.
    (12) For equipment in ethylene oxide service, as defined in Sec.  
63.101, records of the percent ethylene oxide content of the process 
fluid and the method used to determine it.
* * * * *
    (d) * * *
    (5) * * *
    (i) The owner or operator may develop a written procedure that 
identifies the conditions that justify a delay of repair. The written 
procedures may be included as part of the startup/shutdown/malfunction 
plan, required by Sec.  63.6(e)(3), for the source or may be part of a 
separate document that is maintained at the plant site. In such cases, 
reasons for delay of repair may be documented by citing the relevant 
sections of the written procedure. For each source as defined in Sec.  
63.101, and for each source as defined in Sec.  63.191, on and after 
July 15, 2027, the sentence ``The written procedures may be included as 
part of the startup/shutdown/malfunction plan, required by Sec.  
63.6(e)(3), for the source or may be part of a separate document that 
is maintained at the plant site.'' in this paragraph no longer applies.
* * * * *
    (g) * * *
    (1) * * *
    (iii) Except as specified in paragraph (a) of Sec.  63.108, the 
flare design (i.e., steam-assisted, air-assisted, or non-assisted) and 
the results of the compliance demonstration required by Sec.  63.11(b).
* * * * *
    (2) * * *
    (i) Except as specified in paragraph (a) of Sec.  63.108, dates and 
durations when the closed-vent systems and control devices required in 
Sec. Sec.  63.163 through 63.166, and Sec.  63.170 are not operated as 
designed as indicated by the monitored parameters, including periods 
when a flare pilot light system does not have a flame.
* * * * *
    (3) Records of inspections of closed-vent systems subject to the 
provisions of Sec.  63.172, as specified in paragraphs (g)(3)(i) 
through (iii) of this section.
* * * * *
    (iii) For each source as defined in Sec.  63.101, and for each 
source as defined in Sec.  63.191, beginning no later than the 
compliance dates specified in Sec.  63.100(k)(10), the owner or 
operator must comply with this paragraph in addition to the 
requirements in paragraphs (g)(3)(i) and (ii) of this section. For each 
flow event from a bypass line subject to the requirements in Sec.  
63.172(j), the owner or operator must maintain records sufficient to 
determine whether or not the detected flow included flow requiring 
control. For each flow event from a bypass line requiring control that 
is released either directly to the atmosphere or to a control device 
not meeting the requirements in this subpart, the owner or operator 
must include an estimate of the volume of gas, the concentration of 
organic HAP in the gas and the resulting emissions of organic HAP that 
bypassed the control device using process knowledge and engineering 
estimates.
* * * * *
    (1) For fenceline monitoring systems subject to Sec.  63.184, each 
owner or operator must keep the records specified in paragraphs (l)(1) 
through (11) of this section.
    (1) Coordinates of all passive tube and canister monitors, 
including co-located samplers and field blanks, and if applicable, the 
meteorological station. The owner or operator shall determine the 
coordinates using an instrument with an accuracy of at least 3 meters. 
The coordinates shall be in decimal degrees with at least five decimal 
places.
    (2) The start and stop times and dates for each sample, as well as 
the tube or canister identifying information.
    (3) Sampling period average temperature and barometric pressure 
measurements.
    (4) For each outlier determined in accordance with Section 9.2 of 
Method 325A of appendix A of this part the sampler location of and the 
concentration of the outlier and the evidence used to conclude that the 
result is an outlier. The evidence must include documentation of 
accidental contamination by the sample handler. High sample results 
attributed to unknown causes are not outliers if there is no evidence 
of sample contamination and the sample does not meet the requirements 
in Section 9.2 of Method 325A of appendix A of this part.
    (5) For samples that will be adjusted for offsite impacts, the 
location of and the concentration measured simultaneously by the 
additional sampler(s), and the perimeter samplers to which it applies.
    (6) Individual sample results, the calculated [Delta]c for each 
monitored compound for each sampling period and the two samples used to 
determine it, whether correction for offsite impacts was used, and the 
annual average [Delta]c for each monitored compound calculated after 
each sampling period.
    (7) Method detection limit for each sample, including co-located 
samples and blanks.
    (8) Documentation of the root cause analysis and any resulting 
corrective action taken each time an action level is exceeded, 
including the dates the root cause analysis was initiated and the 
resulting correction action(s) were taken. If real-time sampling 
techniques are required under Sec.  63.184(e)(3)(B), the location of 
the real-time monitors for each 48-hour period.
    (9) Any corrective action plan developed under Sec.  63.184(f).
    (10) Other records as required by Methods 325A, 325B, and 327 of 
appendix A of this part.
    (11) If monitoring is conducted using canisters in accordance with 
Sec.  63.184(b), if a near-field source correction is used as provided 
in Sec.  63.184(g), or if an alternative test method is used that 
provides time-resolved measurements, records of hourly meteorological 
data, including temperature, barometric pressure, wind speed and wind 
direction, calculated daily unit vector wind direction and daily sigma 
theta, and other records specified in the site-specific monitoring 
plan.

0
114. Amend Sec.  63.182 by:
0
a. Revising paragraph (a)(3) and adding paragraph (a)(4);
0
b. Revising paragraph (c) introductory text and adding paragraphs 
(c)(5) and (6);
0
c. Revising paragraphs (d) introductory text and (d)(2) introductory 
text; and
0
d. Adding paragraphs (d)(2)(xviii) and (xix) and (e).
    The revisions and additions read as follows:


Sec.  63.182  Reporting requirements.

    (a) * * *
    (3) Periodic Reports described in paragraph (d) of this section,
    (4) Fenceline Monitoring Reports described in paragraph (e) of this 
section, and
* * * * *
    (c) Each owner or operator of a source subject to this subpart 
shall submit a Notification of Compliance Status within 90 days after 
the compliance dates specified in the subpart in this part 63 that 
references this subpart, except as provided in paragraph (c)(4) of this 
section. The owner or operator shall also submit a supplement to the

[[Page 43227]]

Notification of Compliance Status as specified in paragraphs (c)(5) and 
(6) of this section, if applicable.
* * * * *
    (5) For pressure relief devices subject to the pressure release 
management work practice standards in Sec.  63.165(e), owners and 
operators must also submit the information listed in paragraphs 
(c)(5)(i) and (ii) of this section in a supplement to the Notification 
of Compliance Status within 150 days after the first applicable 
compliance date for pressure relief device monitoring.
    (i) A description of the monitoring system to be implemented, 
including the relief devices and process parameters to be monitored, 
and a description of the alarms or other methods by which operators 
will be notified of a pressure release.
    (ii) A description of the prevention measures to be implemented for 
each affected pressure relief device.
    (6) For equipment that are in ethylene oxide service, as defined in 
Sec.  63.101, owners and operators must also submit the information in 
this paragraph in a supplement to the Notification of Compliance Status 
within 150 days after the first applicable compliance date. The 
supplement to the Notification of Compliance Status must identify all 
equipment that are in ethylene oxide service, and include the percent 
ethylene oxide content of the process fluid and the method used to 
determine it.
    (d) The owner or operator of a source subject to this subpart shall 
submit Periodic Reports. On and after July 15, 2027 or once the 
reporting template for this subpart has been available on the CEDRI 
website for 1 year, whichever date is later, owners and operators must 
submit all subsequent reports following the procedure specified in 
Sec.  63.9(k), except any medium submitted through mail must be sent to 
the attention of the Hazardous Organic Chemical Manufacturing Sector 
Lead. Owners and operators must use the appropriate electronic report 
template on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for this subpart. The date report 
templates become available will be listed on the CEDRI website. Unless 
the Administrator or delegated state agency or other authority has 
approved a different schedule for submission of reports under Sec.  
63.9(i) and Sec.  63.10(a), the report must be submitted by the 
deadline specified in this subpart, regardless of the method in which 
the report is submitted. All Periodic Reports must include the 
following general information: company name, address (including 
county), and beginning and ending dates of the reporting period.
* * * * *
    (2) For each process unit complying with the provisions of Sec.  
63.163 through Sec.  63.174, the summary information listed in 
paragraphs (d)(2)(i) through (xix) of this paragraph for each 
monitoring period during the 6-month period.
* * * * *
    (xviii) Compliance reports for pressure relief devices subject to 
the requirements Sec.  63.165(e) must include the information specified 
in paragraphs (d)(2)(xviii)(A) through (C) of this section.
    (A) For pressure relief devices in organic HAP gas or vapor 
service, pursuant to Sec.  63.165(e)(1), report the instrument readings 
and dates for all readings of 500 ppm or greater.
    (B) For pressure relief devices in organic HAP gas or vapor service 
subject to Sec.  63.165(e)(2), report the instrument readings and dates 
of instrument monitoring conducted.
    (C) For pressure relief devices in organic HAP service subject to 
Sec.  63.165(e)(3), report each pressure release to the atmosphere, 
including pressure relief device identification name or number, the 
start date, start time, and duration (in minutes) of the pressure 
release; an estimate of the mass quantity in pounds of each organic HAP 
released; the results of any root cause analysis and corrective action 
analysis completed during the reporting period, including the 
corrective actions implemented during the reporting period; and, if 
applicable, the implementation schedule for planned corrective actions 
to be implemented subsequent to the reporting period.
    (xix) For each source as defined in Sec.  63.101, and for each 
source as defined in Sec.  63.191, beginning no later than the 
compliance dates specified in Sec.  63.100(k)(10), the owner or 
operator must comply with this paragraph in addition to the 
requirements in paragraphs (d)(2)(i) through (d)(2)(xviii) of this 
section. For bypass lines subject to the requirements in Sec.  
63.172(j), the Periodic Report must include the start date, start time, 
duration in hours, estimate of the volume of gas in standard cubic 
feet, the concentration of organic HAP in the gas in parts per million 
by volume and the resulting mass emissions of organic HAP in pounds 
that bypass a control device. For periods when the flow indicator is 
not operating, report the start date, start time, and duration in 
hours.
* * * * *
    (e) For fenceline monitoring systems subject to Sec.  63.184, each 
owner or operator must submit Fenceline Monitoring Reports on a 
quarterly basis using the appropriate electronic report template on the 
CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for this subpart and following the procedure specified in Sec.  
63.9(k), except any medium submitted through mail must be sent to the 
attention of the Hazardous Organic Chemical Manufacturing Sector Lead. 
The first quarterly report must be submitted once the owner or operator 
has obtained 12 months of data. The first quarterly report must cover 
the period beginning on the compliance date that is specified in Sec.  
63.100(k)(12) and ending on March 31, June 30, September 30 or December 
31, whichever date is the first date that occurs after the owner or 
operator has obtained 12 months of data (i.e., the first quarterly 
report will contain between 12 and 15 months of data). Each subsequent 
quarterly report must cover one of the following reporting periods: 
Quarter 1 from January 1 through March 31; Quarter 2 from April 1 
through June 30; Quarter 3 from July 1 through September 30; and 
Quarter 4 from October 1 through December 31. Each quarterly report 
must be electronically submitted no later than 45 calendar days 
following the end of the reporting period.
    (1) Facility name and address (including the county).
    (2) Year and reporting quarter (i.e., Quarter 1, Quarter 2, Quarter 
3, or Quarter 4).
    (3) For each passive tube or canister monitor: The latitude and 
longitude location coordinates; the sampler name; and identification of 
the type of sampler (i.e., regular monitor, extra monitor, duplicate, 
field blank, inactive). Coordinates must be in decimal degrees with at 
least five decimal places.
    (4) The beginning and ending dates for each sampling period.
    (5) Individual sample results for each monitored compound, reported 
in units of [micro]g/m3, for each monitor for each sampling period that 
ends during the reporting period. Results below the method detection 
limit must be flagged as below the detection limit and reported at the 
method detection limit.
    (6) Data flags for each outlier determined in accordance with 
Section 9.2 of Method 325A of appendix A of this part. For each 
outlier, the owner or operator must submit the individual sample result 
of the outlier, as well as the evidence used to conclude that the 
result is an outlier. The evidence must include documentation of 
accidental

[[Page 43228]]

contamination by the sample handler. High sample results attributed to 
unknown causes are not outliers if there is no evidence of sample 
contamination and the sample does not meet the requirements in Section 
9.2 of Method 325A of appendix A of this part.
    (7) The concentration difference ([Delta]c) for each monitored 
compound for each sampling period and the annual average [Delta]c for 
each monitored compound for each sampling period.
    (8) Indication of whether the owner or operator was required to 
develop a corrective action plan under Sec.  63.184(f).
    (9) Data flags for each monitor for each analyte that was skipped 
for the sampling period, if the owner or operator uses an alternative 
sampling frequency under Sec.  63.184(a)(3)(iii) or Sec.  
63.184(b)(2)(iii).

0
115. Amend Sec.  63.183 by revising paragraph (c) introductory text and 
adding paragraph (c)(5) to read as follows:


Sec.  63.183  Implementation and enforcement.

* * * * *
    (c) The authorities that cannot be delegated to State, local, or 
Tribal agencies are as specified in paragraphs (c)(1) through (5) of 
this section.
* * * * *
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.

0
116. Add Sec.  63.184 to read as follows:


Sec.  63.184  Fenceline monitoring provisions.

    For each source as defined in Sec.  63.101, and for each source as 
defined in Sec.  63.191, beginning no later than the compliance dates 
specified in Sec.  63.100(k)(12), the owner or operator must conduct 
sampling along the facility property boundary and analyze the samples 
in accordance with paragraphs (a) through (i) of this section. Sampling 
of benzene, 1,3-butadiene, chloroprene, and ethylene dichloride must be 
conducted in accordance with paragraph (a) of this section. Sampling of 
ethylene oxide and vinyl chloride must be conducted in accordance with 
paragraph (b) of this section. Paragraphs (c) through (i) of this 
section apply for any compound required to be sampled.
    (a) The owner or operator must conduct sampling along the facility 
property boundary and analyze the samples in accordance with Methods 
325A and 325B of appendix A to this part and paragraphs (a)(1) through 
(3) of this section. The monitoring perimeter may be located inside the 
facility, away from the facility property boundary. However, the 
monitoring perimeter must encompass all potential sources of the target 
analyte(s) specified in paragraph (a)(1) of this section that are 
located within the facility's property boundary.
    (1) The owner or operator must monitor the target analyte(s), as 
specified in paragraphs (a)(1)(i) through (iv) of this section. The 
owner or operator must follow the procedure in Section 9.6 of Method 
325B of appendix A to this part to determine the detection limit of 
benzene, 1,3-butadiene, chloroprene, and ethylene dichloride for each 
sampler used to collect samples and blanks.
    (i) If an affected source uses, produces, stores, or emits benzene, 
the owner or operator must include benzene as a target analyte.
    (ii) If an affected source uses, produces, stores, or emits 1,3-
butadiene, the owner or operator must include 1,3-butadiene as a target 
analyte.
    (iii) If an affected source uses, produces, stores, or emits 
chloroprene, the owner or operator must include chloroprene as a target 
analyte.
    (iv) If an affected source uses, produces, stores, or emits 
ethylene dichloride, the owner or operator must include ethylene 
dichloride as a target analyte.
    (2) The owner or operator must determine passive monitor locations 
in accordance with Section 8.2 of Method 325A of appendix A to this 
part.
    (i) As it pertains to this subpart, known sources of VOCs, as used 
in Section 8.2.1.3 in Method 325A of appendix A to this part for siting 
passive monitors, means a wastewater treatment unit, process unit, or 
any emission source requiring control according to the requirements of 
this subpart, including marine vessel loading operations. For marine 
vessel loading operations, one passive monitor should be sited on the 
shoreline adjacent to the dock. For this subpart, an additional monitor 
is not required if the only emission sources within 50 meters of the 
monitoring boundary are equipment leak sources satisfying all of the 
conditions in paragraphs (a)(2)(i)(A) through (C) of this section. If a 
leak is found, it must be repaired no later than 15 calendar days after 
it is detected with no provisions for delay of repair. If a repair is 
not completed within 15 calendar days, the additional passive monitor 
specified in Section 8.2.1.3 in Method 325A of appendix A to this part 
must be used.
    (A) The equipment leak sources in organic HAP service within 50 
meters of the monitoring boundary are limited to valves, pumps, 
connectors, sampling connections, and open-ended lines. If compressors, 
pressure relief devices, or agitators in organic HAP service are 
present within 50 meters of the monitoring boundary, the additional 
passive monitoring location specified in Section 8.2.1.3 in Method 325A 
of appendix A to this part must be used.
    (B) All equipment leak sources in gas or light liquid service (and 
in organic HAP service), including valves, pumps, connectors, sampling 
connections and open-ended lines, must be monitored using Method 21 of 
appendix A-7 to 40 CFR part 60 no less frequently than quarterly with 
no provisions for skip period monitoring, or according to the 
provisions of Sec.  63.11(c) Alternative Work practice for monitoring 
equipment for leaks. For the purpose of this provision, a leak is 
detected if the instrument reading equals or exceeds the applicable 
limits in paragraphs (a)(2)(i)(B)(1) through (5) of this section:
    (1) For valves, pumps or connectors at an existing source, an 
instrument reading of 10,000 ppmv.
    (2) For valves or connectors at a new source, an instrument reading 
of 500 ppmv.
    (3) For pumps at a new source, an instrument reading of 2,000 ppmv.
    (4) For sampling connections or open-ended lines, an instrument 
reading of 500 ppmv above background.
    (5) For equipment monitored according to the Alternative Work 
practice for monitoring equipment for leaks, the leak definitions 
contained in Sec.  63.11(c)(6)(i) through (iii).
    (C) All equipment leak sources in organic HAP service, including 
sources in gas, light liquid and heavy liquid service, must be 
inspected using visual, audible, olfactory, or any other detection 
method at least monthly. A leak is detected if the inspection 
identifies a potential leak to the atmosphere or if there are 
indications of liquids dripping.
    (ii) If there are 19 or fewer monitoring locations, the owner or 
operator must collect at least one co-located duplicate sample per 
sampling period and at least one field blank per sampling period. If 
there are 20 or more monitoring locations, the owner or operator must 
collect at least two co-located duplicate samples per sampling period 
and at least one field blank per sampling period. The co-located 
duplicates may be collected at any of the perimeter sampling.
    (iii) Samplers are not required to be placed along internal roads, 
waterways, or other right of ways that may bisect the facility. If a 
facility is bounded by a waterway on one or more sides, the shoreline 
is considered the facility property boundary.

[[Page 43229]]

    (3) The owner or operator must use a sampling period and sampling 
frequency as specified in paragraphs (a)(3)(i) through (iii) of this 
section.
    (i) Sampling period. A 14-day sampling period must be used, unless 
a shorter sampling period is determined to be necessary under paragraph 
(e) or (g) of this section. A sampling period is defined as the period 
during which sampling tube is deployed at a specific sampling location 
with the diffusive sampling end cap in-place and does not include the 
time required to analyze the sample. For the purpose of this subpart, a 
14-day sampling period may be no shorter than 13 calendar days and no 
longer than 15 calendar days, but the routine sampling period must be 
14 calendar days.
    (ii) Base sampling frequency. Except as provided in paragraph 
(a)(3)(iii) of this section, the frequency of sample collection must be 
once each contiguous 14-day sampling period, such that the beginning of 
the next 14-day sampling period begins immediately upon the completion 
of the previous 14-day sampling period.
    (iii) Alternative sampling frequency for burden reduction. When an 
individual monitor consistently achieves results for a particular 
analyte at or below the level specified in paragraph (a)(4) of this 
section, the owner or operator may elect to use the applicable minimum 
sampling frequency specified in paragraphs (a)(3)(iii)(A) through (E) 
of this section for that monitoring site for that analyte. When 
calculating [Delta]c for the monitoring period when using this 
alternative for burden reduction, use zero for the lowest sampling 
result for each monitoring period where one or more samples was not 
taken and/or analyzed for the analyte(s) that qualifies for this 
alternative sampling frequency. This alternative for burden reduction 
is determined on an analyte specific basis. If an owner or operator is 
not required to sample for a particular analyte for a particular 
monitoring site in accordance with this paragraph (a)(3)(iii), the 
owner or operator must still sample for any other analytes required by 
paragraph (a)(1) of this section at the frequency specified in 
paragraph (a)(3)(ii) of this section, unless the other analyte(s) also 
qualifies for this alternative for burden reduction.
    (A) For the analyte of interest, if every sample at a monitoring 
site is at or below the level specified in paragraph (a)(4) of this 
section for 2 years (52 consecutive samples), every other sampling 
period can be skipped for that analyte for that monitoring site, i.e., 
sampling will occur approximately once per month.
    (B) For the analyte of interest, if every sample at a monitoring 
site that is monitored at the frequency specified in paragraph 
(a)(3)(iii)(A) of this section is at or below the level specified in 
paragraph (a)(4) of this section for 2 years (i.e., 26 consecutive 
``monthly'' samples), five 14-day sampling periods can be skipped for 
that analyte for that monitoring site following each period of 
sampling, i.e., sampling will occur approximately once per quarter.
    (C) For the analyte of interest, if every sample at a monitoring 
site that is monitored at the frequency specified in paragraph 
(a)(3)(iii)(B) of this section is at or below the level specified in 
paragraph (a)(4) of this section for 2 years (i.e., 8 consecutive 
quarterly samples), twelve 14-day sampling periods can be skipped for 
that analyte for that monitoring site following each period of 
sampling, i.e., sampling will occur twice a year.
    (D) For the analyte of interest, if every sample at a monitoring 
site that is monitored at the frequency specified in paragraph 
(a)(3)(iii)(C) of this section is at or below the level specified in 
paragraph (a)(4) of this section for 2 years (i.e., 4 consecutive 
semiannual samples), only one sample per year is required for that 
analyte for that monitoring site. For yearly sampling, samples shall 
occur at least 10 months but no more than 14 months apart.
    (E) If at any time a sample for a monitoring site that is monitored 
for the analyte at the frequency specified in paragraph (a)(3)(iii)(A) 
through (D) of this section returns a result for the analyte that is 
above the level specified in paragraph (a)(4) of this section, the 
sampling site must return to the original sampling requirements for the 
analyte of contiguous 14-day sampling periods with no skip periods for 
one quarter (six 14-day sampling periods). If every sample collected 
for the analyte during this quarter is at or below the level specified 
in paragraph (a)(4) of this section, the owner or operator may revert 
back to the reduced monitoring schedule applicable for that analyte for 
that monitoring site prior to the sample reading exceeding the level 
specified in paragraph (a)(4) of this section. If any sample collected 
for the analyte during this quarter is above the level specified in 
paragraph (a)(4) of this section, that monitoring site must return to 
the original sampling requirements for that analyte of contiguous 14-
day sampling periods with no skip periods for a minimum of two years. 
The burden reduction requirements can be used again for that analyte 
for that monitoring site once the requirements of paragraph 
(a)(3)(iii)(A) of this section are met again, i.e., after 52 contiguous 
14-day samples with no results above the level specified in paragraph 
(a)(4) of this section.
    (4) To use the alternative sampling frequency outlined in paragraph 
(a)(3) of this section, an individual monitor must consistently achieve 
results for the analyte at or below the level specified in paragraphs 
(a)(4)(i) through (iii) of this section.
    (i) For benzene, the results must be consistently at or below 0.9 
[mu]g/m\3\.
    (ii) For 1,3-butadiene, the results must be consistently at or 
below 0.3 [mu]g/m\3\.
    (iii) For ethylene dichloride, the results must be consistently at 
or below 0.4 [mu]g/m\3\.
    (b) The owner or operator must conduct sampling along the facility 
property boundary and analyze the samples in accordance with Method 327 
of appendix A to this part and paragraphs (b)(1) through (3) of this 
section.
    (1) The owner or operator must monitor the target analyte(s), as 
specified in paragraphs (b)(1)(i) and (ii) of this section.
    (i) If an affected source uses, produces, stores, or emits ethylene 
oxide, the owner or operator must include ethylene oxide as a target 
analyte.
    (ii) If an affected source uses, produces, stores, or emits vinyl 
chloride, the owner or operator must include vinyl chloride as a target 
analyte.
    (2) The owner or operator must use a sampling period and sampling 
frequency as specified in paragraphs (b)(2)(i) and (ii) of this 
section.
    (i) Sampling period. A 24-hour sampling period must be used, unless 
a shorter sampling period is determined to be necessary under paragraph 
(e) or (g) of this section. A sampling period is defined as the period 
during which the canister is deployed at a specific sampling location 
and actively sampling and does not include the time required to analyze 
the sample. For the purpose of this subpart, a 24-hour sampling period 
may be no shorter than 23 hours and no longer than 25 hours.
    (ii) Base sampling frequency. Except as provided in paragraph 
(b)(2)(iii) of this section, the frequency of sample collection must be 
once every 5 calendar days, such that the beginning of each sampling 
period begins approximately 96 hours ( 24 hours) from the 
end of the previous sample.
    (iii) Alternative sampling frequency for burden reduction. This 
alternative is only applicable for the measurement of

[[Page 43230]]

vinyl chloride from sites with a monitoring perimeter less than or 
equal to 5,000 meters. When an individual sampling point consistently 
achieves results at or below 0.3 [mu]g/m\3\, the owner or operator may 
elect to use the applicable minimum sampling frequency specified in 
paragraphs (b)(2)(iii)(A) through (E) of this section for that sampling 
site for vinyl chloride. If ethylene oxide is a required analyte, the 
owner or operator must continue to monitor ethylene oxide at the 
frequency specified in paragraph (b)(2)(ii) of this section. When 
calculating [Delta]c for the monitoring period when using this 
alternative for burden reduction, use zero for the lowest sampling 
result for each monitoring period where one or more samples was not 
taken for vinyl chloride.
    (A) If every sample at a monitoring site is at or below 0.3 [mu]g/
m\3\ for 2 years (52 consecutive samples), every other sampling period 
can be skipped for that sampling site, i.e., sampling will occur 
approximately once per month.
    (B) If every sample at a sampling site that is monitored at the 
frequency specified in paragraph (b)(2)(iii)(A) of this section is at 
or below 0.3 [mu]g/m\3\ for 2 years (i.e., 26 consecutive ``monthly'' 
samples), five 14-day sampling periods can be skipped for that sampling 
site following each period of sampling, i.e., sampling will occur 
approximately once per quarter.
    (C) If every sample at a sampling site that is monitored at the 
frequency specified in paragraph (b)(2)(iii)(B) of this section is at 
or below 0.3 [mu]g/m\3\ for 2 years (i.e., 8 consecutive quarterly 
samples), twelve 14-day sampling periods can be skipped for that 
sampling site following each period of sampling, i.e., sampling will 
occur twice a year.
    (D) If every sample at a sampling site that is monitored at the 
frequency specified in paragraph (b)(2)(iii)(C) of this section is at 
or below 0.3 [mu]g/m\3\ for 2 years (i.e., 4 consecutive semiannual 
samples), only one sample per year is required for that sampling site. 
For yearly sampling, samples shall occur at least 10 months but no more 
than 14 months apart.
    (E) If at any time a sample for a sampling site that is monitored 
at the frequency specified in paragraphs (b)(2)(iii)(A) through (E) of 
this section returns a result that is above 0.3 [mu]g/m\3\, the 
sampling site must return to the original sampling requirements of 
sampling every 5 calendar days with no skip periods for one quarter (18 
5-day sampling periods). If every sample collected during this quarter 
is at or below 0.3 [mu]g/m\3\, the owner or operator may revert back to 
the reduced monitoring schedule applicable for that sampling site prior 
to the sample reading exceeding 0.3 [mu]g/m\3\. If any sample collected 
during this quarter is above 0.3 [mu]g/m\3\, that sampling site must 
return to the original sampling requirements of sampling every 5 
calendar days with no skip periods for a minimum of two years. The 
burden reduction requirements can be used again for that sampling site 
once the requirements of paragraph (b)(2)(ii)(A) of this section are 
met again, i.e., after 146 consecutive samples with no results above 
0.3 [mu]g/m\3\.
    (3) The owner or operator must determine canister sample locations 
in accordance with paragraphs (b)(3)(i) through (v) of this section.
    (i) The monitoring perimeter must be located on or inside the 
facility property boundary. If the monitoring perimeter is located away 
from the facility property boundary, the monitoring perimeter must 
encompass all potential sources of the target analyte(s) specified in 
paragraph (b)(1) of this section that are located within the facility's 
property boundary. If the site contains process units that are 
disconnected (i.e., one or more process areas are not within the 
boundary of the main facility), the owner or operator must follow the 
requirements in paragraph (b)(3)(v) of this section. Canisters are not 
required to be placed along internal roads, waterways, or other right 
of ways that may bisect the facility. If a facility is bounded by a 
waterway on one or more sides, the shoreline is considered the facility 
property boundary.
    (ii) The owner or operator must place 8 canisters around the 
monitoring perimeter during each sampling period.
    (iii) To determine sampling locations, measure the length of the 
monitoring perimeter.
    (A) Locate the point on the monitoring perimeter that is closest to 
sources of the target analyte(s). If one of the target analytes is 
ethylene oxide, this point must be the point on the monitoring 
perimeter that is closest to the sources of ethylene oxide.
    (B) If the monitoring perimeter is less than or equal to 5,000 
meters, divide the monitoring perimeter into 8 evenly spaced sampling 
points, with one point located in accordance with the requirements of 
paragraph (b)(3)(iii)(A) of this section.
    (C) If the monitoring perimeter is greater than 5,000 meters, but 
less than or equal to 10,000 meters, divide the monitoring perimeter 
into 16 evenly spaced sampling points, with one point located in 
accordance with the requirements of paragraph (b)(3)(iii)(A) of this 
section.
    (D) If the monitoring perimeter is greater than 10,000 meters, 
divide the monitoring perimeter into 24 evenly spaced sampling points, 
with one point located in accordance with the requirements of paragraph 
(b)(3)(iii)(A) of this section.
    (iv) Place canisters on the monitoring perimeter at the sampling 
points as follows.
    (A) If there are only 8 sampling points for the site, monitor each 
sampling point during each sampling period.
    (B) If there are 16 sampling points for the site, number the 
sampling points consecutively along the monitoring perimeter. During 
the first sampling period, monitor the odd numbered sampling points. 
During the second sampling period, monitor the even numbered sampling 
points. Continue to alternate between the odd numbered and even 
numbered sampling points in subsequent sampling periods.
    (C) If there are 24 sampling points for the site, number the 
sampling points consecutively along the monitoring perimeter. During 
the first sampling period, monitor every third sampling point starting 
with the first sampling point (i.e., points 1, 4, 7, etc.). During the 
second sampling period, monitor every third sampling point starting 
with the second sampling point (i.e., points 2, 5, 8, etc.). During the 
third sampling period, monitor every third sampling point starting with 
the third sampling point (i.e., points 3, 6, 9, etc.). Continue to 
alternate between these placements for each subsequent sampling period 
(i.e., the fourth sampling period will include every third sampling 
point starting with the first sampling point, the fifth sampling period 
will include every third sampling point starting with the second 
sampling point, and so on).
    (v) If the site consists of small areas disconnected from the main 
facility, additional monitors must be placed on these areas in 
accordance with paragraphs (b)(3)(v)(A) through (C) of this section. 
The monitoring perimeter for the disconnected area(s) must be located 
between the property boundary of the area and the process unit(s), such 
that the monitoring perimeter for the disconnected area encompasses all 
potential sources of the target analyte(s) specified in paragraph 
(b)(1) of this section.
    (A) If the disconnected area is less than 50 acres, the owner or 
operator must sample at two locations each sampling period. One 
location must be placed in the expected prevailing wind direction for 
the sampling period, downwind of the main source of

[[Page 43231]]

emissions of the target analyte(s). The other location must be located 
on the monitoring perimeter at 180 degrees from the first sample 
location.
    (B) If the disconnected area is equal to or greater than 50 acres 
but less than or equal to 150 acres, the owner or operator must sample 
at four equally spaced locations. One sampling point must be located on 
the monitoring perimeter at the point that is closest to sources of the 
target analyte(s). If one of the target analytes is ethylene oxide, 
this point must be the point on the monitoring perimeter that is 
closest to the sources of ethylene oxide.
    (C) If the disconnected area is greater than 150 acres, the 
sampling points for the disconnected area must be determined according 
to paragraphs (b)(3)(ii) through (iv) of this section.
    (4) At least one co-located duplicate sample and at least one field 
blank must be collected per sampling period.
    (5) The owner or operator must follow the procedures in Method 327 
of appendix A to this part to determine the detection limit of the 
target analyte(s) and requirements for quality assurance samples.
    (c) The owner or operator must collect and record meteorological 
data according to the applicable requirements in paragraphs (c)(1) 
through (3) of this section.
    (1) If monitoring is conducted under paragraph (b) of this section, 
if a near-field source correction is used as provided in paragraph 
(g)(2) of this section, or if an alternative test method is used that 
provides time-resolved measurements, the owner or operator must use an 
on-site meteorological station in accordance with Section 8.3 of Method 
325A of appendix A to this part. Collect and record hourly average 
meteorological data, including temperature, barometric pressure, wind 
speed and wind direction and calculate daily unit vector wind direction 
and daily sigma theta.
    (2) For cases other than those specified in paragraph (c)(1) of 
this section, the owner or operator must collect and record sampling 
period average temperature and barometric pressure using either an on-
site meteorological station in accordance with Section 8.3 of Method 
325A of appendix A to this part or, alternatively, using data from a 
National Weather Service (NWS) meteorological station provided the NWS 
meteorological station is within 40 kilometers (25 miles) of the 
facility.
    (3) If an on-site meteorological station is used, the owner or 
operator must follow the calibration and standardization procedures for 
meteorological measurements in EPA-454/B-08-002 (incorporated by 
reference, see Sec.  63.14).
    (d) Within 45 days of completion of each sampling period, the owner 
or operator must determine whether the results are above or below the 
action level for each measured compound as follows. If the owner or 
operator is required to monitor any small disconnected area(s) of the 
facility under paragraph (b)(3)(v) of this section, the procedure for 
determining whether the results are above or below the action level for 
each measured compound must be performed for the disconnected area(s) 
separately.
    (1) The owner or operator must determine the facility impact on the 
concentration ([Delta]c) of each compound for each sampling period 
according to either paragraph (d)(1)(i) or (ii) of this section, as 
applicable.
    (i) Except when near-field source correction is used as provided in 
paragraph (d)(1)(ii) of this section, the owner or operator must 
determine the highest and lowest sample results for each compound 
individually from the sample pool and calculate each compound's 
[Delta]c as the difference in these concentrations. Co-located samples 
must be averaged together for the purposes of determining the 
concentration at a particular sampling location, and, if applicable, 
for determining [Delta]c. The owner or operator must adhere to the 
following procedures when one or more samples for the sampling period 
are below the method detection limit for a particular compound:
    (A) If the lowest detected value of a compound is below detection, 
the owner or operator must use zero as the lowest sample result when 
calculating [Delta]c.
    (B) If all sample results are below the method detection limit, the 
owner or operator must use the highest method detection limit for the 
sample set as the highest sample result and zero as the lowest sample 
result when calculating [Delta]c.
    (C) In the case of co-located samples, if one sample is above the 
method detection limit while the other sample is below the method 
detection limit, the owner or operator must use the method detection 
limit as the result for the sample that is below the method detection 
limit for purposes of averaging the results to determine the 
concentration at a particular sampling location, and, if applicable, 
for determining [Delta]c.
    (ii) When near-field source correction for a compound is used as 
provided in paragraph (g) of this section, the owner or operator must 
determine [Delta]c using the calculation protocols outlined in 
paragraph (d)(1)(i) of this section, except as provided in this 
paragraph (d)(1)(ii), and the additional requirements in paragraph 
(g)(2) of this section, as well as any additional requirements outlined 
in the approved site-specific monitoring plan. The [Delta]c for the 
compound for the sampling period is equal to the higher of the values 
in paragraphs (d)(1)(ii)(A) and (B) of this section.
    (A) The highest corrected sample result for the compound from a 
sampling location where near-field source correction for the compound 
is used during the sampling period.
    (B) The difference in concentration between the highest sample 
result that was not corrected for a near-field source for the compound 
during the sampling period and the lowest sample result for the 
compound for the sampling period.
    (2) The owner or operator must calculate the annual average 
[Delta]c for each monitored compound as follows:
    (i) For sampling conducted under paragraph (a) of this section, the 
annual average [Delta]c for each compound is based on the average of 
the [Delta]c values for the 26 most recent 14-day sampling periods. The 
owner or operator must update this annual average value after receiving 
the results of each subsequent 14-day sampling period.
    (ii) For sampling conducted under paragraph (b) of this section, 
the annual average [Delta]c for each compound is based on the average 
of the [Delta]c values for the 73 most recent sampling periods. The 
owner or operator must update this annual average value after receiving 
the results of each subsequent sampling period.
    (3) The action level for each compound is listed in paragraphs 
(d)(3)(i) through (vi) of this section. If the annual average [Delta]c 
value for a compound is greater than the listed action level for the 
compound, the concentration is above the action level, and the owner or 
operator must conduct a root cause analysis and corrective action in 
accordance with paragraph (e) of this section.
    (i) The action level for benzene is 9 micrograms per cubic meter 
([mu]g/m\3\) on an annual average basis.
    (ii) The action level for 1,3-butadiene is 3 [mu]g/m\3\ on an 
annual average basis.
    (iii) The action level for chloroprene is 0.8 [mu]g/m\3\ on an 
annual average basis.
    (iv) The action level for ethylene oxide is 0.2 [mu]g/m\3\ on an 
annual average basis.
    (v) The action level for vinyl chloride is 3 [mu]g/m\3\ on an 
annual average basis.

[[Page 43232]]

    (vi) The action level for ethylene dichloride is 4 [mu]g/m\3\ on an 
annual average basis.
    (e) Once any action level in paragraph (d)(3) of this section has 
been exceeded, the owner or operator must take the following actions to 
bring the annual average [Delta]c back below the action level(s).
    (1) Within 5 days of updating the annual average value as required 
in paragraph (d)(2) of this section and determining that any action 
level in paragraph (d)(3) of this section has been exceeded (i.e., in 
no case longer than 50 days after completion of the sampling period), 
the owner or operator must initiate a root cause analysis to determine 
appropriate corrective action. A root cause analysis is an assessment 
conducted through a process of investigation to determine the primary 
underlying cause and all other contributing causes to an exceedance of 
an action level(s) set forth in paragraph (d)(3) of this section.
    (i) The initial root cause analysis may include, but is not limited 
to:
    (A) Leak inspection using Method 21 of appendix A-7 to 40 CFR part 
60, optical gas imaging, or handheld monitors.
    (B) Visual inspection to determine the cause of the high emissions.
    (C) Operator knowledge of process changes (e.g., a malfunction or 
release event).
    (ii) If the initial root cause cannot be identified using the type 
of techniques described in paragraph (e)(1)(i) of this section, the 
owner or operator must employ more frequent sampling and analysis to 
determine the root cause of the exceedance.
    (A) The owner or operator may first employ additional monitoring 
points and shorter sampling periods for Methods 325A and 325B of 
appendix A to this part for benzene, 1,3-butadiene, chloroprene, or 
ethylene dichloride or more frequent sampling with Method 327 of 
appendix A to this part for ethylene oxide or vinyl chloride to 
determine the root cause of the exceedance.
    (B) If the owner or operator has not determined the root cause of 
the exceedance within 30 days of determining that the action level has 
been exceeded, the owner or operator must employ the appropriate real-
time sampling techniques (e.g., mobile gas chromatographs, optical 
spectroscopy instruments, sensors) to locate the cause of the 
exceedance. If the root cause is not identified after 48 hours, either 
the real-time monitor must be relocated or an additional real-time 
monitor must be added. Relocation or addition of extra real-time 
monitors must continue after each 48-hour period of nonidentification 
until the owner or operator can identify the root cause of the 
exceedance.
    (2) If the underlying primary and other contributing causes of the 
exceedance are deemed to be under the control of the owner or operator, 
the owner or operator must take appropriate corrective action as 
expeditiously as possible to bring annual average fenceline 
concentrations back below the action level(s) set forth in paragraph 
(d)(3) of this section. At a minimum, the corrective actions taken must 
address the underlying primary and other contributing cause(s) 
determined in the root cause analysis to prevent future exceedances 
from the same underlying cause(s).
    (3) The root cause analysis must be completed and initial 
corrective actions taken no later than 45 days after determining there 
is an exceedance of an action level.
    (4) Until the annual average [Delta]c is below the action level 
again, following completion of the initial corrective action, the owner 
or operator must conduct a new root cause analysis according to this 
paragraph (e), and if required, submit a corrective action plan under 
paragraph (f) of this section following any sampling period for which 
the sampling start time begins after the completion of the initial 
corrective actions and for which the [Delta]c for the sampling period 
is greater than the level specified in paragraphs (e)(4)(i) through 
(vi) of this section for the compound(s) that initially exceeded the 
action level.
    (i) For benzene, a sampling period [Delta]c of 9 [mu]g/m\3\.
    (ii) For 1,3-butadiene, a sampling period [Delta]c of 3 [mu]g/m\3\.
    (iii) For chloroprene, a sampling period [Delta]c of 0.8 [mu]g/
m\3\.
    (iv) For ethylene dichloride, a sampling period [Delta]c of 4 
[mu]g/m\3\.
    (v) For ethylene oxide, a sampling period [Delta]c of 0.2 [mu]g/
m\3\.
    (vi) For vinyl chloride, a sampling period [Delta]c of 3 [mu]g/
m\3\.
    (f) An owner or operator must develop a corrective action plan if 
the conditions in paragraphs (f)(1), (2), or (3) of this section are 
met. The corrective action plan must describe the corrective action(s) 
completed to date, additional measures that the owner or operator 
proposes to employ to reduce annual average fenceline concentrations 
below the action level(s) set forth in paragraph (d)(3) of this 
section, and a schedule for completion of these measures. The 
corrective action plan does not need to be approved by the 
Administrator. However, if upon review, the Administrator disagrees 
with the additional measures outlined in the plan, the owner or 
operator must revise and resubmit the plan within 7 calendar days of 
receiving comments from the Administrator.
    (1) If the compound that exceeded the action level was benzene, 
1,3-butadiene, chloroprene, or ethylene dichloride, the owner or 
operator must develop a corrective action plan if, upon completion of 
the root cause analysis and initial corrective actions required in 
paragraph (e) of this section, the [Delta]c value for the next sampling 
period, for which the sampling start time begins after the completion 
of the initial corrective actions, is greater than the level specified 
in paragraphs (f)(1)(i) through (iv) of this section for the 
compound(s) that initially exceeded the action level. The corrective 
action plan must include the implementation of real-time sampling 
techniques to locate the primary and other contributing causes of the 
exceedance. The owner or operator must submit the corrective action 
plan to the Administrator within 60 days after receiving the analytical 
results indicating that the [Delta]c value for the sampling period 
following the completion of the initial corrective action is greater 
than the level specified in paragraphs (f)(1)(i) through (iv) of this 
section.
    (i) For benzene, a sampling period [Delta]c of 9 [mu]g/m\3\.
    (ii) For 1,3-butadiene, a sampling period [Delta]c of 3 [mu]g/m\3\.
    (iii) For chloroprene, a sampling period [Delta]c of 0.8 [mu]g/
m\3\.
    (iv) For ethylene dichloride, a sampling period [Delta]c of 4 
[mu]g/m\3\.
    (2) If the compound that exceeded the action level was ethylene 
oxide or vinyl chloride, the owner or operator must develop a 
corrective action plan if, upon completion of the root cause analysis 
and initial corrective actions required in paragraph (e) of this 
section, the [Delta]c value for any of the next three sampling periods, 
for which the sampling start time begins after the completion of the 
initial corrective actions, is greater than the level specified in 
paragraphs (f)(2)(i) and (ii) of this section for the compound(s) that 
initially exceeded the action level. The corrective action plan must 
include the implementation of real-time sampling techniques to locate 
the primary and other contributing causes of the exceedance. The owner 
or operator must submit the corrective action plan to the Administrator 
within 60 days after receiving the analytical results indicating that 
the [Delta]c value for the sampling period following the completion of 
the initial corrective

[[Page 43233]]

action is greater than the level specified in paragraphs (f)(2)(i) and 
(ii) of this section.
    (i) For ethylene oxide, a sampling period [Delta]c of 0.2 [mu]g/
m\3\.
    (ii) For vinyl chloride, a sampling period [Delta]c of 3 [mu]g/
m\3\.
    (3) The owner or operator must develop a corrective action plan if 
complete implementation of all corrective measures identified in the 
root cause analysis required by paragraph (e) of this section will 
require more than 45 days. The owner or operator must submit the 
corrective action plan to the Administrator no later than 60 days 
following the completion of the root cause analysis required in 
paragraph (e) of this section.
    (g) An owner or operator may request approval from the 
Administrator for a site-specific monitoring plan to account for 
offsite upwind sources according to the requirements in paragraphs 
(g)(1) through (4) of this section.
    (1) The owner or operator must prepare and submit a site-specific 
monitoring plan and receive approval of the site-specific monitoring 
plan prior to using the near-field source alternative calculation for 
determining [Delta]c provided in paragraph (g)(2) of this section. The 
site-specific monitoring plan must include, at a minimum, the elements 
specified in paragraphs (g)(1)(i) through (vi) of this section. The 
procedures in Section 12 of Method 325A of appendix A to this part are 
not required, but may be used, if applicable, when determining near-
field source contributions.
    (i) Identification of the near-field source or sources.
    (ii) Location of the additional monitoring stations that will be 
used to determine the near-field source concentration contribution. The 
owner or operator must use additional monitoring stations to determine 
the near-field source contribution.
    (iii) Identification of the fenceline monitoring locations impacted 
by the near-field source. If more than one near-field source is 
present, identify the near-field source or sources that are expected to 
contribute to the concentration at that monitoring location.
    (iv) A description of (including sample calculations illustrating) 
the planned data reduction; the treatment of invalid data, data below 
detection limits, and data collected during calm wind periods; and 
calculations to determine the near-field source concentration 
contribution for each monitoring location.
    (v) A detailed description of the measurement technique, 
measurement location(s), the standard operating procedures, measurement 
frequency, recording frequency, measurement detection limit, and data 
quality indicators to ensure accuracy, precision, and validity of the 
data.
    (vi) A detailed description of how data will be handled during 
periods of calm wind conditions (i.e., less than 2 miles per hour).
    (2) When an approved site-specific monitoring plan is used, the 
owner or operator must determine [Delta]c for comparison with the 
action level according to paragraph (d) of this section. When 
determining the highest and lowest sample results for use in the 
[Delta]c calculation, the concentration for any monitor that has been 
corrected using an approved site-specific monitoring plan will be 
corrected according to the procedures specified in paragraphs (g)(2)(i) 
and (ii) of this section.
    (i) For each monitoring location corrected using the site-specific 
monitoring plan, the corrected fenceline concentration at that 
monitoring station will be equal to the fenceline concentration 
measured with Methods 325A and 325B or Method 327 of appendix A to this 
part minus the near-field source contributing concentration at the 
measurement location determined using the additional measurements and 
calculation procedures included in the site-specific monitoring plan.
    (ii) If the fenceline concentration at the monitoring station is 
below the method detection limit for Methods 325A and 325B or Method 
327 of appendix A to this part, no near-field source contribution can 
be subtracted from that monitoring station for that sampling period.
    (3) The site-specific monitoring plan must be submitted and 
approved as described in paragraphs (g)(3)(i) through (iv) of this 
section.
    (i) The site-specific monitoring plan must be submitted to the 
Administrator for approval.
    (ii) The site-specific monitoring plan must also be submitted to 
the following address: U.S. Environmental Protection Agency, Office of 
Air Quality Planning and Standards, Sector Policies and Programs 
Division, U.S. EPA Mailroom (E143-01), Attention: Hazardous Organic 
Chemical Manufacturing Sector Lead, 109 T.W. Alexander Drive, P.O. Box 
12055, Research Triangle Park, NC 27711. Electronic copies in lieu of 
hard copies may also be submitted to [email protected].
    (iii) The Administrator will approve or disapprove the plan in 90 
days. The plan is considered approved if the Administrator either 
approves the plan in writing or fails to disapprove the plan in 
writing. The 90-day period begins when the Administrator receives the 
plan.
    (iv) If the Administrator finds any deficiencies in the site-
specific monitoring plan and disapproves the plan in writing, the owner 
or operator may revise and resubmit the site-specific monitoring plan 
following the requirements in paragraphs (g)(3)(i) and (ii) of this 
section. The 90-day period starts over with the resubmission of the 
revised monitoring plan.
    (4) The approval by the Administrator of a site-specific monitoring 
plan will be based on the completeness, accuracy and reasonableness of 
the request for a site-specific monitoring plan. Factors that the 
Administrator will consider in reviewing the request for a site-
specific monitoring plan include, but are not limited to, those 
described in paragraphs (g)(4)(i) through (v) of this section.
    (i) The identification of the near-field source or sources and 
evidence of how the sources impact the fenceline concentrations.
    (ii) The location(s) selected for additional monitoring to 
determine the near-field source concentration contribution.
    (iii) The identification of the fenceline monitoring locations 
impacted by the near-field source or sources.
    (iv) The appropriateness of the planned data reduction and 
calculations to determine the near-field source concentration 
contribution for each monitoring location, including the handling of 
invalid data, data below the detection limit, and data during calm 
periods.
    (v) The adequacy of the description of and rationale for the 
measurement technique, measurement location(s), the standard operation 
procedure, measurement frequency, recording frequency, measurement 
detection limit, and data quality indicators to ensure accuracy, 
precision, and validity of the data.
    (h) The owner or operator must comply with the applicable 
recordkeeping and reporting requirements in Sec. Sec.  63.181 and 
63.182.
    (i) As outlined in Sec.  63.7(f), the owner or operator may submit 
a request for an alternative test method. At a minimum, the request 
must follow the requirements outlined in paragraphs (i)(1) through (7) 
of this section.
    (1) The alternative method may be used in lieu of all or a partial 
number of passive samplers required in Method 325A of appendix A to 
this part or the canister sampling locations required under paragraph 
(b) of this section.
    (2) The alternative method must be validated according to Method 
301 in

[[Page 43234]]

appendix A to this part or contain performance-based procedures and 
indicators to ensure self-validation.
    (3) The method detection limit must nominally be at least one-third 
of the action level for the compound(s) that will be monitored with the 
alternative method. The alternate test method must describe the 
procedures used to provide field verification of the detection limit.
    (4) If the alternative test method will be used to replace some or 
all passive samplers required under paragraph (a) of this section, the 
spatial coverage must be equal to or better than the spatial coverage 
provided in Method 325A of appendix A to this part. If the alternative 
test method will be used to replace some or all canisters required 
under paragraph (b) of this section, the spatial coverage must be equal 
to or better than the spatial coverage provided under paragraph (b) of 
this section.
    (i) For path average concentration open-path instruments, the 
physical path length of the measurement must be no more than a passive 
sample footprint (the spacing that would be provided by the sorbent 
traps when following Method 325A of appendix A to this part) or 
canister sample footprint, as applicable. For example, if Method 325A 
requires spacing monitors A and B 610 meters (2,000 feet) apart, then 
the physical path length limit for the measurement at that portion of 
the fenceline must be no more than 610 meters (2,000 feet).
    (ii) For range resolved open-path instrument or approach, the 
instrument or approach must be able to resolve an average concentration 
over each passive sampler footprint or canister sample footprint within 
the path length of the instrument.
    (iii) The extra samplers required in Sections 8.2.1.3 of Method 
325A of appendix A to this part may be omitted when they fall within 
the path length of an open-path instrument.
    (5) At a minimum, non-integrating alternative test methods must 
provide a minimum of one cycle of operation (sampling, analyzing, and 
data recording) for each successive 15-minute period.
    (6) For alternative test methods capable of real time measurements 
(less than a 5 minute sampling and analysis cycle), the alternative 
test method may allow for elimination of data points corresponding to 
outside emission sources for purpose of calculation of the high point 
for the two week average. The alternative test method approach must 
have wind speed, direction and stability class of the same time 
resolution and within the footprint of the instrument.
    (7) For purposes of averaging data points to determine the [Delta]c 
for the individual sampling period, all results measured under the 
method detection limit must use the method detection limit. For 
purposes of averaging data points for the individual sampling period 
low sample result, all results measured under the method detection 
limit must use zero.

0
117. Revise tables 1 through 4 to subpart H to read as follows:

                                Table 1 to Subpart H of Part 63--Batch Processes
                           [Monitoring frequency for equipment other than connectors]
----------------------------------------------------------------------------------------------------------------
                                           Equivalent continuous process monitoring frequency time in use
    Operating time (% of year)     -----------------------------------------------------------------------------
                                           Monthly               Quarterly                 Semiannually
----------------------------------------------------------------------------------------------------------------
0 to <25..........................  Quarterly............  Annually.............  Annually.
25 to <50.........................  Quarterly............  Semiannually.........  Annually.
50 to <75.........................  Bimonthly............  Three times..........  Semiannually.
75 to 100.........................  Monthly..............  Quarterly............  Semiannually.
----------------------------------------------------------------------------------------------------------------


   Table 2 to Subpart H of Part 63--Surge Control Vessels and Bottoms
                      Receivers at Existing Sources
------------------------------------------------------------------------
                                                      Vapor pressure \1\
           Vessel capacity (cubic meters)                (kilopascals)
------------------------------------------------------------------------
75 <= capacity <151.................................              >=13.1
151 <= capacity.....................................           \a\ >=5.2
------------------------------------------------------------------------
\1\ Maximum true vapor pressure of total organic HAP at operating
  temperature as defined in subpart G of this part.


   Table 3 to Subpart H of Part 63--Surge Control Vessels and Bottoms
                        Receivers at New Sources
------------------------------------------------------------------------
                                                      Vapor pressure \1\
           Vessel capacity (cubic meters)                (kilopascals)
------------------------------------------------------------------------
38 <= capacity <151.................................              >=13.1
151 <= capacity.....................................               >=0.7
------------------------------------------------------------------------
\1\ Maximum true vapor pressure of total organic HAP at operating
  temperature as defined in subpart G of this part.


   Table 4 to Subpart H of Part 63--Applicable 40 CFR Part 63 General
                               Provisions
------------------------------------------------------------------------
      40 CFR part 63, subpart A, provisions applicable to subpart H
-------------------------------------------------------------------------
Sec.   63.1(a)(1), (a)(2), (a)(3), (a)(13), (a)(14), (b)(2) and (c)(4).
Sec.   63.2.
Sec.   63.5(a)(1), (a)(2), (b), (d)(1)(ii), (d)(4), (e), (f)(1) and
 (f)(2).
Sec.   63.6(a), (b)(3), (c)(5), (i)(1), (i)(2), (i)(4)(i)(A), (i)(5)
 through (i)(14), (i)(16) and (j).
Sec.   63.9(a)(2), (b)(4)(i),\a\ (b)(4)(ii), (b)(4)(iii), (b)(5),\a\
 (c), (d), (j) and (k).
Sec.   63.10(d)(4).
Sec.   63.11 (c), (d), and (e).

[[Page 43235]]

 
Sec.   63.12(b).
------------------------------------------------------------------------
\a\ The notifications specified in Sec.   63.9(b)(4)(i) and (b)(5) shall
  be submitted at the times specified in 40 CFR part 65.


0
118. Revise the heading to subpart I to read as follows:

Subpart I--National Emission Standards for Hazardous Air Pollutants 
for Certain Processes Subject to the Negotiated Regulation for 
Equipment Leaks

0
119. Amend Sec.  63.192 by:
0
a. Revising paragraphs (b)(6), (7) and (10), and adding paragraph 
(b)(12); revising paragraph (c)(3) and adding paragraph (c)(5); and
0
b. Revising and republishing paragraph (f)(2) and revising (g) 
introductory text.
    The revisions, additions and republication read as follows:


Sec.  63.192  Standard.

* * * * *
    (b) * * *
    (6)(i) Except as specified in paragraph (b)(12) of this section, 
the compliance with standards and maintenance requirements of Sec.  
63.6(a), (b)(3), (c)(5), (e), (i)(1), (i)(2), (i)(4)(i)(A), (i)(6)(i), 
(i)(8) through (i)(10), (i)(12) through (i)(14), (i)(16), and (j);
    (ii) Except as specified in paragraph (b)(12) of this section, the 
operational and maintenance requirements of Sec.  63.6(e). The startup, 
shutdown, and malfunction plan requirement of Sec.  63.6(e)(3) is 
limited to control devices subject to the provisions of subpart H of 
this part and is optional for other equipment subject to subpart H. The 
startup, shutdown, and malfunction plan may include written procedures 
that identify conditions that justify a delay of repair. On and after 
July 15, 2027, the last two sentences of this paragraph do not apply.
    (7) With respect to flares, except as specified in paragraph 
(b)(12) of this section, the performance testing requirements of Sec.  
63.7(a)(3), (d), (e)(1), (e)(2), (e)(4), and (h);
* * * * *
    (10) Except as specified in paragraph (b)(12) of this section, the 
control device requirements of Sec.  63.11(b); and
* * * * *
    (12) On and after July 15, 2027, Sec.  63.6(e)(1)(i), (e)(1)(ii), 
and (e)(3), Sec.  63.7(e)(1), and Sec.  63.11(b) do not apply. Instead, 
you must comply with paragraphs (b)(12)(i) through (iii) of this 
section.
    (i) The owner or operator of a source subject to this subpart shall 
comply with the requirements at all times, except during periods of 
nonoperation of the source (or specific portion thereof) resulting in 
cessation of the emissions to which this subpart or subpart H of this 
part applies.
    (ii) At all times, owners and operators subject to this subpart 
must operate and maintain any source, including associated air 
pollution control equipment and monitoring equipment, in a manner 
consistent with safety and good air pollution control practices for 
minimizing emissions. The general duty to minimize emissions does not 
require owners and operators to make any further efforts to reduce 
emissions if levels required by the applicable standard have been 
achieved. Determination of whether a source is operating in compliance 
with operation and maintenance requirements will be based on 
information available to the Administrator which may include, but is 
not limited to, monitoring results, review of operation and maintenance 
procedures, review of operation and maintenance records, and inspection 
of the source.
    (iii) Owners and operators that use a flare to comply with this 
subpart must comply with Sec.  63.108.
    (c) * * *
    (3) Performance tests shall be conducted according to the 
provisions of Sec.  63.7(e), except that performance tests shall be 
conducted at maximum representative operating conditions for the 
process except as specified in paragraph (c)(5) of this section. During 
the performance test, an owner or operator may operate the control or 
recovery device at maximum or minimum representative operating 
conditions for monitored control or recovery device parameters, 
whichever results in lower emission reduction.
* * * * *
    (5) On and after July 15, 2027, in lieu of the requirements 
specified in Sec.  63.7(e)(1) you must conduct performance tests under 
such conditions as the Administrator specifies based on representative 
performance of the affected source for the period being tested. 
Representative conditions exclude periods of startup and shutdown. You 
may not conduct performance tests during periods of malfunction. You 
must record the process information that is necessary to document 
operating conditions during the test and include in such record an 
explanation to support that such conditions represent normal operation. 
Upon request, you must make available to the Administrator such records 
as may be necessary to determine the conditions of performance tests.
* * * * *
    (f) * * *
    (2) The owner or operator subject to subparts I and H of this part 
shall keep the records specified in this paragraph, as well as records 
specified in subpart H of this part.
    (i) Records of the occurrence and duration of each start-up, 
shutdown, and malfunction of operation of a process subject to this 
subpart as specified in Sec.  63.190(b). On and after July 15, 2027, 
this paragraph no longer applies; however, for historical compliance 
purposes, a copy of these records must be retained and available on-
site for at least five years after the date of occurrence.
    (ii) Records of the occurrence and duration of each malfunction of 
air pollution control equipment or continuous monitoring systems used 
to comply with subparts I and H of this part.
    (iii) For each start-up, shutdown, and malfunction, records that 
the procedures specified in the source's start-up, shutdown, and 
malfunction plan were followed, and documentation of actions taken that 
are not consistent with the plan. These records may take the form of a 
``checklist,'' or other form of recordkeeping that confirms conformance 
with the startup, shutdown, and malfunction plan for the event. On and 
after July 15, 2027, this paragraph no longer applies; however, for 
historical compliance purposes, a copy of the plan and these records 
must be retained and available on-site for at least five years after 
the date of occurrence.
    (g) All reports required under subpart H shall be submitted as 
required in Sec.  63.182.
* * * * *

0
120. Amend Sec.  63.480 by revising paragraphs (j) introductory text 
and (j)(4) introductory text as follows:

[[Page 43236]]

Sec.  63.480  Applicability and designation of affected sources.

* * * * *
    (j) Applicability of this subpart. Paragraphs (j)(1) through (3) of 
this section must be followed during periods of non-operation of the 
affected source or any part thereof.
* * * * *
    (4) Beginning on July 15, 2024, this paragraph (j)(4) no longer 
applies. In response to an action to enforce the standards set forth in 
this subpart, an owner or operator may assert an affirmative defense to 
a claim for civil penalties for exceedances of such standards that are 
caused by a malfunction, as defined in Sec.  63.2. Appropriate 
penalties may be assessed, however, if the owner or operator fails to 
meet the burden of proving all the requirements in the affirmative 
defense. The affirmative defense shall not be available for claims for 
injunctive relief.
* * * * *

0
121. Amend Sec.  63.481 by revising paragraph (a), (b), (c) 
introductory text, (d) introductory text, (k), and adding paragraphs 
(k)(2) and (n) through (p) as follows:


Sec.  63.481  Compliance dates and relationship of this subpart to 
existing applicable rules.

    (a) Affected sources are required to achieve compliance on or 
before the dates specified in paragraphs (b) through (d) of this 
section and paragraphs (n) and (o) of this section. Paragraph (e) of 
this section provides information on requesting compliance extensions. 
Paragraphs (f) through (l) of this section discuss the relationship of 
this subpart to subpart A and to other applicable rules. Where an 
override of another authority of the Act is indicated in this subpart, 
only compliance with the provisions of this subpart is required. 
Paragraph (m) of this section specifies the meaning of time periods.
    (b) Except as specified in paragraphs (n) and (o) of this section, 
new affected sources that commence construction or reconstruction after 
June 12, 1995 shall be in compliance with this subpart upon initial 
start-up or by June 19, 2000, whichever is later.
    (c) With the exceptions provided in paragraphs (c)(1) through (3) 
of this section and paragraphs (n) and (o) of this section, existing 
affected sources shall be in compliance with this subpart no later than 
June 19, 2001, as provided in Sec.  63.6(c), unless an extension has 
been granted as specified in paragraph (e) of this section.
* * * * *
    (d) Except as provided for in paragraphs (d)(1) through (d)(6) of 
this section, and paragraphs (n) and (o) of this section, existing 
affected sources shall be in compliance with Sec.  63.502 no later than 
July 31, 1997, unless an extension has been granted pursuant to 
paragraph (e) of this section.
* * * * *
    (k) Applicability of other regulations for monitoring, 
recordkeeping or reporting with respect to combustion devices, recovery 
devices, or recapture devices. (1) After the compliance dates specified 
in this subpart, if any combustion device, recovery device or recapture 
device subject to this subpart is also subject to monitoring, 
recordkeeping, and reporting requirements in 40 CFR part 264 subpart AA 
or CC, or is subject to monitoring and recordkeeping requirements in 40 
CFR part 265 subpart AA or CC and the owner or operator complies with 
the periodic reporting requirements under 40 CFR part 264 subpart AA or 
CC that would apply to the device if the facility had final-permitted 
status, the owner or operator may elect to comply either with the 
monitoring, recordkeeping and reporting requirements of this subpart, 
or with the monitoring, recordkeeping and reporting requirements in 40 
CFR parts 264 and/or 265, as described in this paragraph, which shall 
constitute compliance with the monitoring, recordkeeping and reporting 
requirements of this subpart. The owner or operator shall identify 
which option has been selected in the Notification of Compliance Status 
required by Sec.  63.506(e)(5).
    (2) Owners and operators of flares that are subject to the flare 
related requirements of this subpart and are also subject to flare 
related requirements of any other regulation in this part or 40 CFR 
part 61 or 63, may elect to comply with the requirements in Sec.  
63.508 in lieu of all flare related requirements in any other 
regulation in this part or 40 CFR part 61 or 63.
* * * * *
    (n) All affected sources that commenced construction or 
reconstruction on or before April 25, 2023, must be in compliance with 
the requirements listed in paragraphs (n)(1) through (9) of this 
section upon initial startup or on July 15, 2027, whichever is later. 
All affected sources that commenced construction or reconstruction 
after April 25, 2023, must be in compliance with the requirements 
listed in paragraphs (n)(1) through (9) of this section upon initial 
startup, or on July 15, 2024, whichever is later.
    (1) The general requirements specified in Sec.  63.483(e), Sec.  
63.504(a), Sec.  63.504(a)(1)(iii), and Sec.  63.506(e)(6)(iii)(C).
    (2) For flares, the requirements specified in Sec.  63.508.
    (3) For storage vessels, the requirements specified in Sec.  
63.484(t) and Sec.  63.506(e)(4)(ii)(F)(6).
    (4) For continuous front-end process vents, the requirements 
specified in Sec. Sec.  63.485(l)(6), (o)(6), (p)(5), (q)(1)(vii), (x), 
Sec.  63.503(g)(2)(iii)(B)(4), and Sec.  63.506(e)(4)(ii)(F)(6).
    (5) For batch front-end process vents, the requirements specified 
in Sec. Sec.  63.487(a)(3), (b)(3), and (e)(1)(iv) and (i), Sec. Sec.  
63.488(d)(2), (e)(4), (f)(2), and (g)(3), Sec. Sec.  63.489(b)(10) and 
(d)(3), Sec. Sec.  63.491(d)(1)(iii), (e)(6), and (h), Sec.  63.492(g), 
and Table 6 to this subpart, item 3 in column 3 for diversion to the 
atmosphere and monthly inspections of sealed valves for all control 
devices.
    (6) For back-end processes, the requirements specified in 
Sec. Sec.  63.497(a)(8) and (d)(3), and Sec.  63.498(d)(5)(v).
    (7) For wastewater, the requirements specified in Sec. Sec.  
63.501(d), (e), and (f).
    (8) For equipment leaks, the requirements specified in Sec. Sec.  
63.502(a)(2) and (k)(2).
    (9) For heat exchange systems, the requirements specified in 
Sec. Sec.  63.502(n)(7) and (n)(8).
    (o) All affected sources that commenced construction or 
reconstruction on or before April 25, 2023, must be in compliance with 
the chloroprene requirements in Sec. Sec.  63.484(u), 63.485(y) and 
(z), 63.487(j), 63.494(a)(7), 63.501(a)(10)(iv), 63.502(a)(3) and 
(a)(7), 63.509, and 63.510 upon initial startup or on October 15, 2024, 
whichever is later. All affected sources that commenced construction or 
reconstruction after April 25, 2023, must be in compliance with the 
chloroprene requirements in Sec. Sec.  63.484(u), 63.485(x) and (z), 
63.487(j), 63.494(a)(7), Sec.  63.501(a)(10)(iv), 63.502(q), 
63.502(a)(3) and (a)(7), 63.509, and 63.510 upon initial startup, or on 
July 15, 2024, whichever is later.
    (p) The compliance schedule for fenceline monitoring is specified 
in paragraphs (p)(1) and (2) of this section.
    (1) Except as specified in paragraph (p)(2) of this section, all 
affected sources that commenced construction or reconstruction on or 
before April 25, 2023, must commence fenceline monitoring according to 
the requirements in Sec.  63.502(a)(4) by no later than July 15, 2026, 
however requirements for corrective actions are not required until on 
or after July 15, 2027. All affected sources that commenced 
construction or

[[Page 43237]]

reconstruction after April 25, 2023, must be in compliance with the 
fenceline monitoring requirements listed in Sec.  63.502(a)(4) upon 
initial startup, or on July 15, 2024, whichever is later.
    (2) For affected sources producing neoprene, the compliance 
schedule specified in paragraph (p)(1) of this section does not apply 
for chloroprene. Instead, all affected sources producing neoprene that 
commenced construction or reconstruction on or before April 25, 2023, 
must be in compliance with the fenceline monitoring requirements for 
chloroprene listed in Sec.  63.502(a)(4) and (a)(7) upon initial 
startup or on October 15, 2024, whichever is later. All affected 
sources producing neoprene that commenced construction or 
reconstruction after April 25, 2023, must be in compliance with the 
fenceline monitoring requirements for chloroprene listed in Sec.  
63.502(a)(4) and (a)(7) upon initial startup, or on July 15, 2024, 
whichever is later.

0
122. Revise and republish Sec.  63.482 to read as follows:


Sec.  63.482  Definitions.

    (a) The following terms used in this subpart shall have the meaning 
given them in Sec.  63.2, Sec.  63.101, or the Act, as specified after 
each term:

Act (Sec.  63.2)
Administrator (Sec.  63.2)
Automated monitoring and recording system (Sec.  63.101)
Boiler (Sec.  63.101)
Bottoms receiver (Sec.  63.101)
Breakthrough (Sec.  63.101)
By compound (Sec.  63.101)
By-product (Sec.  63.101)
Car-seal (Sec.  63.101)
Closed-vent system (Sec.  63.101)
Combustion device (Sec.  63.101)
Commenced (Sec.  63.2)
Compliance date (Sec.  63.2)
Connector (Sec.  63.101)
Continuous monitoring system (Sec.  63.2)
Distillation unit (Sec.  63.101)
Duct work (Sec.  63.101)
Emission limitation (Section 302(k) of the Act)
Emission standard (Sec.  63.2)
Emissions averaging (Sec.  63.2)
EPA (Sec.  63.2)
Equipment leak (Sec.  63.101)
External floating roof (Sec.  63.101)
Fill or filling (Sec.  63.101)
Fixed capital cost (Sec.  63.2)
Flame zone (Sec.  63.101)
Floating roof (Sec.  63.101)
Flow indicator (Sec.  63.101)
Fuel gas system (Sec.  63.101)
Halogens and hydrogen halides (Sec.  63.101)
Hard-piping (Sec.  63.101)
Hazardous air pollutant (Sec.  63.2)
Heat exchange system (Sec.  63.101)
Impurity (Sec.  63.101)
Incinerator (Sec.  63.101)
In organic hazardous air pollutant service or in organic HAP service 
(Sec.  63.101)
Instrumentation system (Sec.  63.101)
Internal floating roof (Sec.  63.101)
Lesser quantity (Sec.  63.2)
Major source (Sec.  63.2)
Malfunction (Sec.  63.2)
Oil-water separator or organic-water separator (Sec.  63.101)
Open-ended valve or line (Sec.  63.101)
Operating permit (Sec.  63.101)
Organic monitoring device (Sec.  63.101)
Owner or operator (Sec.  63.2)
Performance evaluation (Sec.  63.2)
Performance test (Sec.  63.2)
Permitting authority (Sec.  63.2)
Plant site (Sec.  63.101)
Potential to emit (Sec.  63.2)
Pressure release (Sec.  63.101)
Primary fuel (Sec.  63.101)
Pressure release (Sec.  63.101)
Pressure relief device (Sec.  63.101)
Pressure vessel (Sec.  63.101)
Process heater (Sec.  63.101)
Process unit shutdown (Sec.  63.101)
Process wastewater (Sec.  63.101)
Process wastewater stream (Sec.  63.101)
Reactor (Sec.  63.101)
Recapture device (Sec.  63.101)
Relief valve (Sec.  63.101)
Repaired (Sec.  63.101)
Research and development facility (Sec.  63.101)
Routed to a process or route to a process (Sec.  63.101)
Run (Sec.  63.2)
Secondary fuel (Sec.  63.101)
Sensor (Sec.  63.101)
Specific gravity monitoring device (Sec.  63.101)
Start-up, shutdown, and malfunction plan (Sec.  63.101) On and after 
July 15, 2027, this definition no longer applies.
State (Sec.  63.2)
Stationary Source (Sec.  63.2)
Surge control vessel (Sec.  63.101)
Temperature monitoring device (Sec.  63.101)
Test method (Sec.  63.2)
Treatment process (Sec.  63.101)
Unit operation (Sec.  63.101)
Visible emission (Sec.  63.2)
Secondary fuel (Sec.  63.101)
Sensor (Sec.  63.101)
Specific gravity monitoring device (Sec.  63.101)
Start-up, shutdown, and malfunction plan (Sec.  63.101) On and after 
July 15, 2027, this definition no longer applies.
State (Sec.  63.2)
Stationary Source (Sec.  63.2)
Surge control vessel (Sec.  63.101)
Temperature monitoring device (Sec.  63.101)
Test method (Sec.  63.2)
Treatment process (Sec.  63.101)
Unit operation (Sec.  63.101)
Visible emission (Sec.  63.2)

    (b) All other terms used in this subpart shall have the meaning 
given them in this section. If a term is defined in a subpart 
referenced in this section, it shall have the meaning given in this 
section for purposes of this subpart.
    Affected source is defined in Sec.  63.480(a).
    Affirmative defense means, in the context of an enforcement 
proceeding, a response or a defense put forward by a defendant, 
regarding which the defendant has the burden of proof, and the merits 
of which are independently and objectively evaluated in a judicial or 
administrative proceeding. Beginning on July 15, 2024, this definition 
of affirmative defense no longer applies.
    Aggregate batch vent stream means a gaseous emission stream 
containing only the exhausts from two or more batch front-end process 
vents that are ducted, hard-piped, or otherwise connected together for 
a continuous flow.
    Annual average batch vent concentration is determined using 
Equation 17, as described in Sec.  63.488(h)(2) for halogenated 
compounds.
    Annual average batch vent flow rate is determined by the procedures 
in Sec.  63.488(e)(3).
    Annual average concentration, as used in the wastewater provisions, 
means the flow-weighted annual average concentration, as determined 
according to the procedures specified in Sec.  63.144(b), with the 
exceptions noted in Sec.  63.501, for the purposes of this subpart.
    Annual average flow rate, as used in the wastewater provisions, 
means the annual average flow rate, as determined according to the 
procedures specified in Sec.  63.144(c), with the exceptions noted in 
Sec.  63.501, for the purposes of this subpart.
    Average batch vent concentration is determined by the procedures in 
Sec.  63.488(b)(5)(iii) for HAP concentrations and is determined by the 
procedures in Sec.  63.488(h)(1)(iii) for organic compounds containing 
halogens and hydrogen halides.
    Average batch vent flow rate is determined by the procedures in 
Sec.  63.488(e)(1) and (2).
    Back-end refers to the unit operations in an EPPU following the 
stripping operations. Back-end process operations include, but are not 
limited to, filtering,

[[Page 43238]]

coagulation, blending, concentration, drying, separating, and other 
finishing operations, as well as latex and crumb storage. Back-end does 
not include storage and loading of finished product or emission points 
that are regulated under Sec.  63.484, Sec.  63.501, or Sec.  63.502.
    Batch cycle means the operational step or steps, from start to 
finish, that occur as part of a batch unit operation.
    Batch emission episode means a discrete emission venting episode 
associated with a single batch unit operation. Multiple batch emission 
episodes may occur from a single batch unit operation.
    Batch front-end process vent means a process vent with annual 
organic HAP emissions greater than 225 kilograms per year from a batch 
unit operation within an affected source and located in the front-end 
of a process unit. Annual organic HAP emissions are determined as 
specified in Sec.  63.488(b) at the location specified in Sec.  
63.488(a)(2).
    Batch mass input limitation means an enforceable restriction on the 
total mass of HAP or material that can be input to a batch unit 
operation in one year.
    Batch mode means the discontinuous bulk movement of material 
through a unit operation. Mass, temperature, concentration, and other 
properties may vary with time. For a unit operation operated in a batch 
mode (i.e., batch unit operation), the addition of material and 
withdrawal of material do not typically occur simultaneously.
    Batch process means, for the purposes of this subpart, a process 
where the reactor(s) is operated in a batch mode.
    Batch unit operation means a unit operation operated in a batch 
mode.
    Block polymer means a polymer where the polymerization is 
controlled, usually by performing discrete polymerization steps, such 
that the final polymer is arranged in a distinct pattern of repeating 
units of the same monomer.
    Butyl rubber means a copolymer of isobutylene and other monomers. 
Typical other monomers include isoprene and methylstyrene. A typical 
composition of butyl rubber is approximately 85- to 99-percent 
isobutylene, and 1- to 15-percent other monomers. Most butyl rubber is 
produced by precipitation polymerization, although other methods may be 
used. Halobutyl rubber is a type of butyl rubber elastomer produced 
using halogenated copolymers.
    Combined vent stream, as used in reference to batch front-end 
process vents, continuous front-end process vents, and aggregate batch 
vent streams, means the emissions from a combination of two or more of 
the aforementioned types of process vents. The primary occurrence of a 
combined vent stream is as combined emissions from a continuous front-
end process vent and a batch front-end process vent.
    Combustion device burner means a device designed to mix and ignite 
fuel and air to provide a flame to heat and oxidize waste organic 
vapors in a combustion device.
    Compounding unit means a unit operation which blends, melts, and 
resolidifies solid polymers for the purpose of incorporating additives, 
colorants, or stabilizers into the final elastomer product. A unit 
operation whose primary purpose is to remove residual monomers from 
polymers is not a compounding unit.
    Construction means the on-site fabrication, erection, or 
installation of an affected source. Construction also means the on-site 
fabrication, erection, or installation of a process unit or combination 
of process units which subsequently becomes an affected source or part 
of an affected source, due to a change in primary product.
    Continuous front-end process vent means a process vent located in 
the front-end of a process unit and containing greater than 0.005 
weight percent total organic HAP from a continuous unit operation 
within an affected source. The total organic HAP weight percent is 
determined after the last recovery device, as described in Sec.  
63.115(a), and is determined as specified in Sec.  63.115(c).
    Continuous mode means the continuous movement of material through a 
unit operation. Mass, temperature, concentration, and other properties 
typically approach steady-state conditions. For a unit operation 
operated in a continuous mode (i.e., continuous unit operation), the 
simultaneous addition of raw material and withdrawal of product is 
typical.
    Continuous process means, for the purposes of this subpart, a 
process where the reactor(s) is operated in a continuous mode.
    Continuous record means documentation, either in hard copy or 
computer readable form, of data values measured at least once every 15 
minutes and recorded at the frequency specified in Sec.  63.506(d) or 
(h).
    Continuous recorder means a data recording device that either 
records an instantaneous data value at least once every 15 minutes or 
records 1--hour or more frequent block average values.
    Continuous unit operation means a unit operation operated in a 
continuous mode.
    Control device is defined in Sec.  63.111, except that the term 
``continuous front-end process vent'' shall apply instead of the term 
``process vent,'' for the purpose of this subpart.
    Crumb rubber dry weight means the weight of the polymer, minus the 
weight of water and residual organics.
    Dioxins and furans means total tetra- through octachlorinated 
dibenzo-p-dioxins and dibenzofurans.
    Drawing unit means a unit operation which converts polymer into a 
different shape by melting or mixing the polymer and then pulling it 
through an orifice to create a continuously extruded product.
    Elastomer means any polymer having a glass transition temperature 
lower than -10 [deg]C, or a glass transition temperature between -10 
[deg]C and 25 [deg]C that is capable of undergoing deformation 
(stretching) of several hundred percent and recovering essentially when 
the stress is removed. For the purposes of this subpart, resins are not 
considered to be elastomers.
    Elastomer product means one of the following types of products, as 
they are defined in this section:
    (i) Butyl Rubber;
    (ii) Epichlorohydrin Elastomer;
    (iii) Ethylene Propylene Rubber;
    (iv) Hypalon\TM\;
    (v) Neoprene;
    (vi) Nitrile Butadiene Rubber;
    (vii) Nitrile Butadiene Latex;
    (viii) Polybutadiene Rubber/Styrene Butadiene Rubber by Solution;
    (ix) Polysulfide Rubber;
    (x) Styrene Butadiene Rubber by Emulsion; and
    (xi) Styrene Butadiene Latex.
    Elastomer product process unit (EPPU) means a collection of 
equipment assembled and connected by hard-piping or duct work, used to 
process raw materials and to manufacture an elastomer product as its 
primary product. This collection of equipment includes unit operations; 
recovery operations equipment; process vents; storage vessels, as 
determined in Sec.  63.480(g); equipment that is identified in Sec.  
63.149; and the equipment that is subject to the equipment leak 
provisions as specified in Sec.  63.502. Utilities, lines and equipment 
not containing process fluids, and other non-process lines, such as 
heating and cooling systems which do not combine their materials with 
those in the processes they serve, are not part of an elastomer product 
process unit. An elastomer product process unit consists of more than 
one unit operation.
    Elastomer type means one of the elastomers listed under ``elastomer 
product'' in this section. Each elastomer identified in that definition 
represents a different elastomer type.
    Emission point means an individual continuous front-end process 
vent,

[[Page 43239]]

batch front-end process vent, back-end process vent, storage vessel, 
waste management unit, heat exchange system, or equipment leak, or 
equipment subject to Sec.  63.149.
    Emulsion process means a process where the monomer(s) is dispersed 
in droplets throughout a water phase, with the aid of an emulsifying 
agent such as soap or a synthetic emulsifier. The polymerization occurs 
either within the emulsion droplet or in the aqueous phase.
    Epichlorohydrin elastomer means an elastomer formed from the 
polymerization or copolymerization of epichlorohydrin (EPI). The main 
epichlorohydrin elastomers are polyepichlorohydrin, epi-ethylene oxide 
(EO) copolymer, epi-allyl glycidyl ether (AGE) copolymer, and epi-EO-
AGE terpolymer. Epoxies produced by the copolymerization of EPI and 
bisphenol A are not epichlorohydrin elastomers.
    Equipment means, for the purposes of the provisions in Sec.  
63.502(a) through (m) and the requirements in subpart H that are 
referred to in Sec.  63.502(a) through (m), each pump, compressor, 
agitator, pressure relief device, sampling connection system, open-
ended valve or line, valve, connector, surge control vessel, bottoms 
receiver, and instrumentation system in organic hazardous air pollutant 
service; and any control devices or systems required by subpart H of 
this part.
    Ethylene-propylene rubber means an ethylene-propylene copolymer or 
an ethylene-propylene terpolymer. Ethylene-propylene copolymers (EPM) 
result from the polymerization of ethylene and propylene and contain a 
saturated chain of the polymethylene type. Ethylene-propylene 
terpolymers (EPDM) are produced in a similar manner as EPM, except that 
a third monomer is added to the reaction sequence. Typical third 
monomers include ethylidene norbornene, 1,4-hexadiene, or 
dicyclopentadiene. Ethylidene norbornene is the most commonly used. The 
production process includes, but is not limited to, polymerization, 
recycle, recovery, and packaging operations. The polymerization 
reaction may occur in either a solution process or a suspension 
process.
    Existing affected source is defined in Sec.  63.480(a)(3).
    Existing process unit means any process unit that is not a new 
process unit.
    Extruding unit means a unit operation which converts polymer into a 
different shape by melting or mixing the polymer and then forcing it 
through an orifice to create a continuously extruded product.
    Flexible operation unit means a process unit that manufactures 
different chemical products, polymers, or resins periodically by 
alternating raw materials or operating conditions. These units are also 
referred to as campaign plants or blocked operations.
    Front-end refers to the unit operations in an EPPU prior to, and 
including, the stripping operations. For all gas-phased reaction 
processes, all unit operations are considered to be front-end.
    Gas-phased reaction process means an elastomer production process 
where the reaction occurs in a gas phase, fluidized bed.
    Glass transition temperature means the temperature at which an 
elastomer polymer becomes rigid and brittle.
    Grade means a group of recipes of an elastomer type having similar 
characteristics such as molecular weight, monomer composition, 
significant mooney values, and the presence or absence of extender oil 
and/or carbon black. More than one recipe may be used to produce the 
same grade.
    Group 1 batch front-end process vent means, before July 15, 2027, a 
batch front-end process vent releasing annual organic HAP emissions 
greater than or equal to 11,800 kg/yr and with a cutoff flow rate, 
calculated in accordance with Sec.  63.488(f), greater than or equal to 
the annual average batch vent flow rate. Annual organic HAP emissions 
and annual average batch vent flow rate are determined at the exit of 
the batch unit operation, as described in Sec.  63.488(a)(2). Annual 
organic HAP emissions are determined as specified in Sec.  63.488(b), 
and annual average batch vent flow rate is determined as specified in 
Sec.  63.488(e). On and after July 15, 2027, Group 1 batch front-end 
process vent means, each batch front-end process vent that, when 
combined, the sum of all these process vents would release annual 
organic HAP emissions greater than or equal to 4,536 kg/yr (10,000 lb/
yr) as determined using the procedures specified in Sec.  63.488(b).
    Group 2 batch front-end process vent means a batch front-end 
process vent that does not fall within the definition of a Group 1 
batch front-end process vent.
    Group 1 continuous front-end process vent means, before July 15, 
2027, a continuous front-end process vent for which the flow rate is 
greater than or equal to 0.005 standard cubic meter per minute, the 
total organic HAP concentration is greater than or equal to 50 parts 
per million by volume, and the total resource effectiveness index 
value, calculated according to Sec.  63.115, is less than or equal to 
1.0. On and after July 15, 2027, Group 1 continuous front-end process 
vent means a process vent that emits greater than or equal to 1.0 pound 
per hour of total organic HAP.
    Group 2 continuous front-end process vent means, before July 15, 
2027, a continuous front-end process vent for which the flow rate is 
less than 0.005 standard cubic meter per minute, the total organic HAP 
concentration is less than 50 parts per million by volume, or the total 
resource effectiveness index value, calculated according to Sec.  
63.115, is greater than 1.0. On and after July 15, 2027, Group 2 
continuous front-end process vent means a process vent that emits less 
than 1.0 pound per hour of total organic HAP.
    Group 1 storage vessel means a storage vessel at an existing 
affected source that meets the applicability criteria specified in 
Table 3 of this subpart, or a storage vessel at a new affected source 
that meets the applicability criteria specified in Table 4 of this 
subpart.
    Group 2 storage vessel means a storage vessel that does not fall 
within the definition of a Group 1 storage vessel.
    Group 1 wastewater stream means a wastewater stream consisting of 
process wastewater from an existing or new affected source that meets 
the criteria for Group 1 status in Sec.  63.132(c), with the exceptions 
listed in Sec.  63.501(a)(10) for the purposes of this subpart (i.e., 
for organic HAP as defined in this section).
    Group 2 wastewater stream means any process wastewater stream that 
does not meet the definition of a Group 1 wastewater stream.
    Halogenated aggregate batch vent stream means an aggregate batch 
vent stream determined to have a total mass emission rate of halogen 
atoms contained in organic compounds of 3,750 kg/yr or greater 
determined by the procedures presented in Sec.  63.488(h).
    Halogenated batch front-end process vent means a batch front-end 
process vent determined to have a mass emission rate of halogen atoms 
contained in organic compounds of 3,750 kg/yr or greater determined by 
the procedures presented in Sec.  63.488(h).
    Halogenated continuous front-end process vent means a continuous 
front-end process vent determined to have a mass emission rate of 
halogen atoms contained in organic compounds of 0.45 kg/hr or greater 
determined by the procedures presented in Sec.  63.115(d)(2)(v).
    High conversion latex means a latex where all monomers are reacted 
to at least 95 percent conversion.
    Highest-HAP recipe for a product means the recipe of the product 
with the highest total mass of HAP charged to the

[[Page 43240]]

reactor during the production of a single batch of product.
    Hypalon\TM\ means a chlorosulfonated polyethylene that is a 
synthetic rubber produced for uses such as wire and cable insulation, 
shoe soles and heels, automotive components, and building products.
    In chloroprene service means the following:
    (i) For process vents, each continuous front-end process vent, each 
batch front-end process vent, and each back-end process vent in a 
process at affected sources producing neoprene that, when uncontrolled, 
contains a concentration of greater than or equal to 1 ppmv undiluted 
chloroprene, and when combined, the sum of all these process vents 
within the process would emit uncontrolled, chloroprene emissions 
greater than or equal to 5 lb/yr (2.27 kg/yr). If information exists 
that suggests chloroprene could be present in a continuous front-end 
process vent, batch front-end process vent, or back-end process vent, 
then the process vent is considered to be ``in chloroprene service'' 
unless an analysis is performed as specified in Sec.  63.509 to 
demonstrate that the process vent does not meet the definition of being 
``in chloroprene service''. Examples of information that could suggest 
chloroprene could be present in a process vent, include calculations 
based on safety data sheets, material balances, process stoichiometry, 
or previous test results provided the results are still relevant to the 
current operating conditions.
    (ii) For storage vessels, storage vessels of any capacity and vapor 
pressure in a process at affected sources producing neoprene storing a 
liquid that is at least 0.1 percent by weight of chloroprene. If 
knowledge exists that suggests chloroprene could be present in a 
storage vessel, then the storage vessel is considered to be ``in 
chloroprene service'' unless the procedures specified in Sec.  63.509 
are performed to demonstrate that the storage vessel does not meet the 
definition of being ``in chloroprene service''. The exemption for 
vessels ``storing and/or handling material that contains no organic 
HAP, or organic HAP as impurities only'' listed in the definition of 
``storage vessel'' in this section does not apply for storage vessels 
that are in chloroprene service. Examples of information that could 
suggest chloroprene could be present in a storage vessel, include 
calculations based on safety data sheets, material balances, process 
stoichiometry, or previous test results provided the results are still 
relevant to the current operating conditions.
    (iii) For wastewater streams, any wastewater stream in a process at 
affected sources producing neoprene that contains total annual average 
concentration of chloroprene greater than or equal to 10 parts per 
million by weight at any flow rate. If knowledge exists that suggests 
chloroprene could be present in a wastewater stream, then the 
wastewater stream is considered to be ``in chloroprene service'' unless 
sampling and analysis is performed as specified in Sec.  63.509 to 
demonstrate that the wastewater stream does not meet the definition of 
being ``in chloroprene service''. Examples of information that could 
suggest chloroprene could be present in a wastewater stream, include 
calculations based on safety data sheets, material balances, process 
stoichiometry, or previous test results provided the results are still 
relevant to the current operating conditions.
    Initial start-up means the first time a new or reconstructed 
affected source begins production of an elastomer product, or, for 
equipment added or changed as described in Sec.  63.480(i), the first 
time the equipment is put into operation to produce an elastomer 
product. Initial start-up does not include operation solely for testing 
equipment. Initial start-up does not include subsequent start-ups of an 
affected source or portion thereof following shutdowns, or following 
changes in product for flexible operation units, or following 
recharging of equipment in batch operation.
    Latex means a colloidal aqueous emulsion of elastomer. A latex may 
be further processed into finished products by direct use as a coating 
or as a foam, or it may be precipitated to separate the rubber 
particles, which are then used in dry state to prepare finished 
products.
    Latex weight includes the weight of the polymer and the weight of 
the water solution.
    Maintenance wastewater is defined in Sec.  63.101, except that the 
term ``elastomer product process unit'' shall apply whenever the term 
``chemical manufacturing process unit'' is used. Further, the 
generation of wastewater from the routine rinsing or washing of 
equipment in batch operation between batches is not maintenance 
wastewater, but is considered to be process wastewater, for the 
purposes of this subpart.
    Maximum true vapor pressure is defined in Sec.  63.111, except that 
the terms ``transfer'' and ``transferred'' shall not apply for the 
purposes of this subpart.
    Multicomponent system means, as used in conjunction with batch 
front-end process vents, a stream whose liquid and/or vapor contains 
more than one compound.
    Neoprene means a polymer of chloroprene (2-chloro-1,3-butadiene). 
The free radical emulsion process is generally used to produce 
neoprene, although other methods may be used.
    New process unit means a process unit for which the construction or 
reconstruction commenced after June 12, 1995.
    Nitrile butadiene latex means a polymer consisting primarily of 
unsaturated nitriles and dienes, usually acrylonitrile and 1,3-
butadiene, that is sold as a latex.
    Nitrile butadiene rubber means a polymer consisting primarily of 
unsaturated nitriles and dienes, usually acrylonitrile and 1,3-
butadiene, not including nitrile butadiene latex.
    On-site or on site means, with respect to records required to be 
maintained by this subpart or required by another subpart referenced by 
this subpart, that records are stored at a location within a major 
source which encompasses the affected source. On-site includes, but is 
not limited to, storage at the affected source or EPPU to which the 
records pertain, or storage in central files elsewhere at the major 
source.
    Operating day means the period defined by the owner or operator in 
the Notification of Compliance Status required by Sec.  63.506(e)(5). 
The operating day is the period for which daily average monitoring 
values and batch cycle daily average monitoring values are determined.
    Organic hazardous air pollutant(s) (organic HAP) means one or more 
of the chemicals listed in table 5 to this subpart or any other 
chemical which:
    (i) Is knowingly produced or introduced into the manufacturing 
process other than as an impurity; and
    (ii) Is listed in table 2 to subpart F of this part.
    Polybutadiene rubber by solution means a polymer of 1,3-butadiene 
produced using a solution process.
    Polysulfide rubber means a polymer produced by reacting sodium 
polysulfide and chloroethyl formal. Polysulfide rubber may be produced 
as latexes or solid product.
    Primary product is defined in and determined by the procedures 
specified in Sec.  63.480(f).
    Process section means the equipment designed to accomplish a 
general but well-defined task in polymers production. Process sections 
include raw materials preparation, polymerization reaction, and 
material recovery. A process section may be dedicated to a single EPPU 
or may be common to more than one EPPU.

[[Page 43241]]

    Process unit means a collection of equipment assembled and 
connected by hard-piping or duct work, used to process raw materials 
and to manufacture a product.
    Process vent means a gaseous emission stream from a unit operation 
that is discharged to the atmosphere either directly or after passing 
through one or more control, recovery, or recapture devices. Unit 
operations that may have process vents are condensers, distillation 
units, reactors, or other unit operations within the EPPU. Process 
vents exclude pressure releases, gaseous streams routed to a fuel gas 
system(s), and leaks from equipment regulated under Sec.  63.502. A 
gaseous emission stream is no longer considered to be a process vent 
after the stream has been controlled and monitored in accordance with 
the applicable provisions of this subpart.
    Product means a polymer produced using the same monomers, and 
varying in additives (e.g., initiators, terminators, etc.); catalysts; 
or in the relative proportions of monomers, that is manufactured by a 
process unit. With respect to polymers, more than one recipe may be 
used to produce the same product, and there can be more than one grade 
of a product. As an example, styrene butadiene latex and butyl rubber 
each represent a different product. Product also means a chemical that 
is not a polymer, is manufactured by a process unit. By-products, 
isolated intermediates, impurities, wastes, and trace contaminants are 
not considered products.
    Recipe means a specific composition, from among the range of 
possible compositions that may occur within a product, as defined in 
this section. A recipe is determined by the proportions of monomers 
and, if present, other reactants and additives that are used to make 
the recipe. For example, styrene butadiene latex without additives; 
styrene butadiene latex with an additive; and styrene butadiene latex 
with different proportions of styrene to butadiene are all different 
recipes of the same product, styrene butadiene latex.
    Reconstruction means the replacement of components of an affected 
source or of a previously unaffected stationary source that becomes an 
affected source as a result of the replacement, to such an extent that:
    (i) The fixed capital cost of the new components exceeds 50 percent 
of the fixed capital cost that would be required to construct a 
comparable new source; and
    (ii) It is technologically and economically feasible for the 
reconstructed source to meet the provisions of this subpart.
    Recovery device means:
    (i) An individual unit of equipment capable of and normally used 
for the purpose of recovering chemicals for:
    (A) Use;
    (B) Reuse;
    (C) Fuel value (i.e., net heating value); or
    (D) For sale for use, reuse, or fuel value (i.e., net heating 
value).
    (ii) Examples of equipment that may be recovery devices include 
absorbers, carbon adsorbers, condensers, oil-water separators or 
organic-water separators, or organic removal devices such as decanters, 
strippers, or thin film evaporation units. For the purposes of the 
monitoring, recordkeeping, or reporting requirements of this subpart, 
recapture devices are considered recovery devices.
    Recovery operations equipment means the equipment used to separate 
the components of process streams. Recovery operations equipment 
includes distillation units, condensers, etc. Equipment used for 
wastewater treatment and recovery or recapture devices used as control 
devices shall not be considered recovery operations equipment.
    Residual is defined in Sec.  63.111, except that when the 
definition in Sec.  63.111 uses the term ``table 9 compounds,'' the 
term ``organic HAP listed in table 5 to subpart U of this part'' shall 
apply, for the purposes of this subpart.
    Resin, for the purposes of this subpart, means a polymer with the 
following characteristics:
    (i) The polymer is a block polymer;
    (ii) The manufactured polymer does not require vulcanization to 
make useful products;
    (iii) The polymer production process is operated to achieve at 
least 99 percent monomer conversion; and
    (iv) The polymer process unit does not recycle unreacted monomer 
back to the process.
    Shutdown means for purposes including, but not limited to, periodic 
maintenance, replacement of equipment, or repair, the cessation of 
operation of an affected source, an EPPU within an affected source, a 
waste management unit or unit operation within an affected source, or 
equipment required or used to comply with this subpart, or the emptying 
or degassing of a storage vessel. For purposes of the wastewater 
provisions of Sec.  63.501, shutdown does not include the routine 
rinsing or washing of equipment in batch operation between batches. For 
purposes of the batch front-end process vent provisions in Sec. Sec.  
63.486 through 63.492, the cessation of equipment in batch operation is 
not a shutdown, unless the equipment undergoes maintenance, is 
replaced, or is repaired.
    Solution process means a process where both the monomers and the 
resulting polymers are dissolved in an organic solvent.
    Start-up means the setting into operation of an affected source, an 
EPPU within the affected source, a waste management unit or unit 
operation within an affected source, or equipment required or used to 
comply with this subpart, or a storage vessel after emptying and 
degassing. For both continuous and batch front-end processes, start-up 
includes initial start-up and operation solely for testing equipment. 
For both continuous and batch front-end processes, start-up does not 
include the recharging of equipment in batch operation. For continuous 
front-end processes, start-up includes transitional conditions due to 
changes in product for flexible operation units. For batch front-end 
processes, start-up does not include transitional conditions due to 
changes in product for flexible operation units.
    Steady-state conditions means that all variables (temperatures, 
pressures, volumes, flow rates, etc.) in a process do not vary 
significantly with time; minor fluctuations about constant mean values 
may occur.
    Storage vessel means a tank or other vessel that is used to store 
liquids that contain one or more organic HAP. Storage vessels do not 
include:
    (i) Vessels permanently attached to motor vehicles such as trucks, 
railcars, barges, or ships;
    (ii) Except for storage vessels in chloroprene service, vessels 
with capacities smaller than 38 cubic meters;
    (iii) Except for storage vessels in chloroprene service, vessels 
and equipment storing and/or handling material that contains no organic 
HAP, or organic HAP as impurities only;
    (iv) Surge control vessels and bottoms receivers; and
    (v) Wastewater storage tanks.
    Stripper means a unit operation where stripping occurs.
    Stripping means the removal of organic compounds from a raw 
elastomer product. In the production of an elastomer, stripping is a 
discrete step that occurs after the reactors and before the dryers 
(other than those dryers with a primary purpose of devolitalization) 
and other finishing operations. Examples of types of stripping include 
steam stripping, direct volatilization, chemical stripping, and other 
methods of devolatilization. For the purposes of this subpart, 
devolatilization that occurs

[[Page 43242]]

in dryers (other than those dryers with a primary purpose of 
devolatilization), extruders, and other finishing operations is not 
stripping.
    Styrene butadiene latex means a polymer consisting primarily of 
styrene and butadiene monomer units produced using an emulsion process 
and sold as a latex.
    Styrene butadiene rubber by emulsion means a polymer consisting 
primarily of styrene and butadiene monomer units produced using an 
emulsion process. Styrene butadiene rubber by emulsion does not include 
styrene butadiene latex.
    Styrene butadiene rubber by solution means a polymer that consists 
primarily of styrene and butadiene monomer units and is produced using 
a solution process.
    Supplemental combustion air means the air that is added to a vent 
stream after the vent stream leaves the unit operation. Air that is 
part of the vent stream as a result of the nature of the unit operation 
is not considered supplemental combustion air. Air required to operate 
combustion device burner(s) is not considered supplemental combustion 
air. Air required to ensure the proper operation of catalytic 
oxidizers, to include the intermittent addition of air upstream of the 
catalyst bed to maintain a minimum threshold flow rate through the 
catalyst bed or to avoid excessive temperatures in the catalyst bed, is 
not considered to be supplemental combustion air.
    Suspension process means a polymerization process where the 
monomer(s) is in a state of suspension, with the help of suspending 
agents in a medium other than water (typically an organic solvent). The 
resulting polymers are not soluble in the reactor medium.
    Total organic compounds (TOC) means those compounds, excluding 
methane and ethane, measured according to the procedures of Method 18 
or Method 25A of appendices A-6 and A-7 to 40 CFR part 60, 
respectively, or ASTM D6420-18 (incorporated by reference, see Sec.  
63.14) as specified in this subpart.
    Total resource effectiveness index value or TRE index value means a 
measure of the supplemental total resource requirement per unit 
reduction of organic HAP associated with a continuous front-end process 
vent stream, based on vent stream flow rate, emission rate of organic 
HAP, net heating value, and corrosion properties (whether or not the 
continuous front-end process vent stream contains halogenated 
compounds), as quantified by the equations given under Sec.  63.115, 
with the exceptions noted in Sec.  63.485.
    Vent stream, as used in reference to batch front-end process vents, 
continuous front-end process vents, and aggregate batch vent streams, 
means the emissions from one or more process vents.
    Waste management unit is defined in Sec.  63.111, except that where 
the definition in Sec.  63.111 uses the term ``chemical manufacturing 
process unit,'' the term ``EPPU'' shall apply for the purposes of this 
subpart.
    Wastewater means water that:
    (i) Contains either:
    (A) An annual average concentration of organic HAP listed in table 
5 to this subpart of at least 5 parts per million by weight and has an 
annual average flow rate of 0.02 liter per minute or greater; or
    (B) An annual average concentration of organic HAP listed in table 
5 to this subpart of at least 10,000 parts per million by weight at any 
flow rate; and
    (ii) Is discarded from an EPPU that is part of an affected source. 
Wastewater is process wastewater or maintenance wastewater.
    Wastewater stream means a stream that contains wastewater as 
defined in this section.

0
123. Amend Sec.  63.483 by revising paragraph (a) introductory text and 
adding paragraph (e) to read as follows:


Sec.  63.483  Emission standards.

    (a) At all times, each owner or operator must operate and maintain 
any affected source subject to the requirements of this subpart, 
including associated air pollution control equipment and monitoring 
equipment, in a manner consistent with safety and good air pollution 
control practices for minimizing emissions. The general duty to 
minimize emissions does not require the owner or operator to make any 
further efforts to reduce emissions if levels required by this standard 
have been achieved. Determination of whether a source is operating in 
compliance with operation and maintenance requirements will be based on 
information available to the Administrator which may include, but is 
not limited to, monitoring results, review of operation and maintenance 
procedures, review of operation and maintenance records, and inspection 
of the source. Except as allowed under paragraphs (b) through (d) of 
this section, the owner or operator of an existing or new affected 
source shall comply with the provisions in paragraphs (a)(1) through 
(a)(9) of this section.
* * * * *
    (e) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), owners and operators of sources as defined in Sec.  63.480 
shall comply with the requirements of this subpart at all times, except 
during periods of nonoperation of the source (or specific portion 
thereof) resulting in cessation of the emissions to which this subpart 
applies.

0
124. Amend Sec.  63.484 by revising paragraphs (a) and (i)(2), and 
adding paragraphs (t) and (u) to read as follows:


Sec.  63.484  Storage vessel provisions.

    (a) This section applies to each storage vessel that is assigned to 
an affected source, as determined by Sec.  63.480(g). Except for those 
storage vessels exempted by paragraph (b) of this section, the owner or 
operator of affected sources shall comply with the requirements of 
Sec. Sec.  63.119 through 63.123 and 63.148, with the differences noted 
in paragraphs (c) through (u) of this section, for the purposes of this 
subpart.
* * * * *
    (i) * * *
    (2) The performance test is submitted as part of the Notification 
of Compliance Status required by Sec.  63.506(e)(5). If the performance 
test report is submitted electronically through the EPA's CEDRI in 
accordance with Sec.  63.152(h), the process unit(s) tested, the 
pollutant(s) tested, and the date that such performance test was 
conducted may be submitted in the notification of compliance status 
report in lieu of the performance test results. The performance test 
results must be submitted to CEDRI by the date the notification of 
compliance status report is submitted.
* * * * *
    (t) Owners and operators of affected sources must make the 
substitutions as specified in paragraphs (t)(1) through (4) of this 
section:
    (1) Substitute ``For each affected source as described in Sec.  
63.480'' for each occurrence of the phrase ``For each source as defined 
in Sec.  63.101''.
    (2) Substitute ``beginning no later than the compliance dates 
specified in Sec.  63.481(n)'' for each occurrence of the phrase 
``beginning no later than the compliance dates specified in Sec.  
63.100(k)(10)''.
    (3) Substitute ``owners and operators of affected sources as 
described in Sec.  63.480'' for each occurrence of the phrase ``owners 
and operators of sources as defined in Sec.  63.101''.
    (4) Substitute ``Sec.  63.508'' for each occurrence of ``Sec.  
63.108''.
    (u) For each affected source as described in Sec.  63.480, 
beginning no later

[[Page 43243]]

than the compliance dates specified in Sec.  63.481(o), if the storage 
vessel (of any capacity and vapor pressure) stores liquid containing 
chloroprene such that the storage vessel is considered to be in 
chloroprene service, as defined in Sec.  63.482, then the owner or 
operator must comply with the requirements of paragraphs (u)(1) through 
(3) of this section in addition to all other applicable requirements 
specified in Sec.  63.483 and elsewhere in this section.
    (1) Reduce emissions of chloroprene by venting emissions through a 
closed vent system to a non-flare control device that reduces 
chloroprene by greater than or equal to 98 percent by weight, or to a 
concentration less than 1 ppmv for each storage vessel vent. If a 
combustion device is used, the chloroprene concentration of 1 ppmv must 
be corrected to 3 percent oxygen.
    (2) To demonstrate compliance with the emission limits specified in 
paragraph (u)(1) of this section for storage vessels in chloroprene 
service, owners and operators must meet the requirements specified in 
Sec.  63.510.
    (3) Owners and operators must keep the records specified in 
paragraphs (u)(3)(i) and (u)(3)(ii) of this section in addition to 
those records specified elsewhere in this section.
    (i) For storage vessels in chloroprene service, records of the 
concentration of chloroprene of the fluid stored in each storage 
vessel.
    (ii) The owner or operator must keep records of all periods during 
which operating values are outside of the applicable operating limits 
specified in Sec.  63.510(b)(4) through (6) when regulated material is 
being routed to the non-flare control device. The record must specify 
the operating parameter, the applicable limit, and the highest (for 
maximum operating limits) or lowest (for minimum operating limits) 
value recorded during the period.

0
125. Amend Sec.  63.485 by:
0
a. Revising paragraphs (a), (l), (o) and (p)(3);
0
b. Adding paragraph (p)(5);
0
c. Revising paragraphs (q)(1) introductory text, (q)(1)(ii), and 
(q)(2);
0
d. Adding paragraph (q)(3);
0
e. Revising paragraphs (s) introductory text, (s)(5), and (t); and
0
f. Adding paragraphs (x), (y) and (z).
    The revisions and additions read as follows:


Sec.  63.485  Continuous front-end process vent provisions.

    (a) For each continuous front-end process vent located at an 
affected source, the owner or operator shall comply with the 
requirements of Sec. Sec.  63.113 through 63.118, except as provided 
for in paragraphs (b) through (z) of this section. The owner or 
operator of continuous front-end process vents that are combined with 
one or more batch front-end process vents shall comply with paragraph 
(o) or (p) of this section.
* * * * *
    (l) When reports of process changes are required under Sec.  
63.118(g), (h), (i), or (j), paragraphs (l)(1) through (4) and (l)(6) 
of this section shall apply for the purposes of this subpart. In 
addition, for the purposes of this subpart paragraph (l)(5) of this 
section applies, and Sec.  63.118(k) does not apply to owners or 
operators of affected sources.
* * * * *
    (2) Except as specified in paragraph (l)(6) of this section, 
whenever a process change, as defined in Sec.  63.115(e), is made that 
causes a Group 2 continuous front-end process vent with a TRE greater 
than 4.0 to become a Group 2 continuous front-end process vent with a 
TRE less than 4.0, the owner or operator shall submit a report within 
180 days after the process change is made or with the next Periodic 
Report, whichever is later. A description of the process change shall 
be submitted with the report of the process change, and the owner or 
operator shall comply with the provisions in Sec.  63.113(d) by the 
dates specified in Sec.  63.481.
    (3) Except as specified in paragraph (l)(6) of this section, 
whenever a process change, as defined in Sec.  63.115(e), is made that 
causes a Group 2 continuous front-end process vent with a flow rate 
less than 0.005 standard cubic meter per minute (scmm) to become a 
Group 2 continuous front-end process vent with a flow rate of 0.005 
scmm or greater and a TRE index value less than or equal to 4.0, the 
owner or operator shall submit a report within 180 days after the 
process change is made or with the next Periodic Report, whichever is 
later. A description of the process change shall be submitted with the 
report of the process change, and the owner or operator shall comply 
with the provisions in Sec.  63.113(d) by the dates specified in Sec.  
63.481.
    (4) Except as specified in paragraph (l)(6) of this section, 
whenever a process change, as defined in Sec.  63.115(e), is made that 
causes a Group 2 continuous front-end process vent with an organic HAP 
concentration less than 50 parts per million by volume (ppmv) to become 
a Group 2 continuous front-end process vent with an organic HAP 
concentration of 50 ppmv or greater and a TRE index value less than or 
equal to 4.0, the owner or operator shall submit a report within 180 
days after the process change is made or with the next Periodic Report, 
whichever is later. A description of the process change shall be 
submitted with the report of the process change, and the owner or 
operator shall comply with the provisions in Sec.  63.113(d) by the 
dates specified in Sec.  63.481.
    (5) * * *
    (iv) Except as specified in paragraph (l)(6) of this section, the 
TRE index value is recalculated according to Sec.  63.115(e) and the 
recalculated value is greater than 4.0.
    (6) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraphs (l)(2), (3), (4), and (l)(5)(iv) of this section 
no longer apply.
* * * * *
    (o) If a batch front-end process vent or aggregate batch vent 
stream is combined with a continuous front-end process vent, the owner 
or operator of the affected source containing the combined vent stream 
shall comply with paragraph (o)(1); with paragraph (o)(2) and (o)(6) 
with paragraph (o)(3) or (o)(4); or with paragraph (o)(5) of this 
section, as appropriate.
* * * * *
    (2) Except as specified in paragraph (o)(6) of this section, if a 
batch front-end process vent or aggregate batch vent stream is combined 
with a continuous front-end process vent prior to the combined vent 
stream being routed to a recovery device, the TRE index value for the 
combined vent stream shall be calculated at the exit of the last 
recovery device. The TRE shall be calculated during periods when one or 
more batch emission episodes are occurring that result in the highest 
organic HAP emission rate (in the combined vent stream that is being 
routed to the recovery device) that is achievable during the 6-month 
period that begins 3 months before and ends 3 months after the TRE 
calculation, without causing any of the situations described in 
paragraphs (o)(2)(i) through (o)(2)(iii) of this section to occur.
* * * * *
    (3) Except as specified in paragraph (o)(6) of this section, if the 
combined vent stream described in paragraph (o)(2) of this section 
meets the requirements in paragraphs (o)(3)(i), (o)(3)(ii), and 
(o)(3)(iii) of this section, the combined vent stream shall be subject 
to the requirements for Group 1 process vents in Sec. Sec.  63.113 
through 63.118, except as otherwise provided in this section, as 
applicable. Performance tests for the combined vent stream shall be 
conducted at maximum

[[Page 43244]]

representative operating conditions, as described in paragraph (o)(1) 
of this section.
* * * * *
    (4) Except as specified in paragraph (o)(6) of this section, if the 
combined vent stream described in paragraph (o)(2) of this section 
meets the requirements in paragraph (o)(4)(i), (ii), or (iii) of this 
section, the combined vent stream shall be subject to the requirements 
for Group 2 process vents in Sec. Sec.  63.113 through 63.118, except 
as otherwise provided in this section, as applicable.
* * * * *
    (6) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraphs (o)(2) through (4) of this section no longer 
apply.
    (p) * * *
    (3) Except as specified in paragraph (p)(5) of this section, the 
efficiency of the final recovery device (determined according to 
paragraph (p)(4) of this section) shall be applied to the total organic 
HAP or TOC concentration measured at the sampling site described in 
paragraph (p)(2) of this section to determine the exit concentration. 
This exit concentration of total organic HAP or TOC shall then be used 
to perform the calculations outlined in Sec.  63.115(d)(2)(iii) and 
Sec.  63.115(d)(2)(iv), for the combined vent stream exiting the final 
recovery device.
* * * * *
    (5) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), the last sentence in paragraph (p)(3) of this section: 
``This exit concentration of total organic HAP or TOC shall then be 
used to perform the calculations outlined in Sec.  63.115(d)(2)(iii) 
and Sec.  63.115(d)(2)(iv), for the combined vent stream exiting the 
final recovery device.'' no longer applies.
    (q) * * *
    (1) Group 1 halogenated continuous front-end process vents at 
existing affected sources producing butyl rubber or ethylene propylene 
rubber using a solution process are exempt from the provisions of Sec.  
63.113(a)(1)(ii) and Sec.  63.113(c) if the conditions in paragraphs 
(q)(1)(i) and (ii) of this section are met, and shall comply with the 
requirements in paragraphs (q)(1)(iii) through (vi) of this section. 
Group 1 halogenated continuous front-end process vents at new affected 
sources producing butyl rubber or ethylene propylene rubber using a 
solution process are not exempt from Sec.  63.113(a)(1)(ii) and Sec.  
63.113(c).
* * * * *
    (ii) Except as specified in paragraph (q)(3) of this section, if 
the requirements of Sec.  63.113(a)(2); Sec.  63.113(a)(3); Sec.  
63.113(b) and the associated testing requirements in Sec.  63.116; or 
Sec.  63.11(b) and Sec.  63.504(c) are met.
* * * * *
    (2) Except as specified in paragraph (q)(3) of this section, Group 
1 halogenated continuous front-end process vents at new and existing 
affected sources producing an elastomer using a gas-phased reaction 
process, provided that the requirements of Sec.  63.113(a)(2); Sec.  
63.113(a)(3); Sec.  63.113(b) and the associated testing requirements 
in Sec.  63.116; or Sec.  63.11(b) and Sec.  63.504(c) are met.
    (3) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraphs (q)(1)(ii) and (q)(2) of this section no longer 
apply. Instead, the requirements of Sec.  63.113(a)(2); Sec. Sec.  
63.113(b) and the associated testing requirements in Sec.  63.116; or 
Sec.  63.508 must be met.
* * * * *
    (s) Internal combustion engines. In addition to the three options 
for the control of a Group 1 continuous front-end process vent listed 
in Sec.  63.113(a)(1) through (3), except as specified in Sec.  
63.113(a)(4) of subpart G of this part, an owner or operator will be 
permitted to route emissions of organic HAP to an internal combustion 
engine, provided the conditions listed in paragraphs (s)(1) through 
(s)(5) of this section are met.
* * * * *
    (5) The owner or operator shall include in the Periodic Report a 
report of all times that the internal combustion engine was not 
operating while emissions were being routed to it. Include the start 
date and time and end date and time for all such periods.
* * * * *
    (t) When the provisions of Sec.  63.116(c)(3) and (4) specify that 
Method 18 of appendix A-6 to 40 CFR part 60 must be used, Method 18 or 
Method 25A of appendices A-6 and A-7 to 40 CFR part 60, respectively, 
may be used for the purposes of this subpart. ASTM D6420-18 
(incorporated by reference, see Sec.  63.14) may also be used in lieu 
of Method 18, if the target compounds are all known and are all listed 
in Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 must not 
be used for methane and ethane; and ASTM D6420-18 may not be used as a 
total VOC method. The use of Method 25A must conform with the 
requirements in paragraphs (t)(1) and (2) of this section.
    (1) The organic HAP used as the calibration gas for Method 25A of 
appendix A-7 to 40 CFR part 60 must be the single organic HAP 
representing the largest percent by volume of the emissions.
* * * * *
    (x) Owners and operators of affected sources must make the 
substitutions as specified in paragraphs (x)(1) through (4) of this 
section:
    (1) Substitute ``For each affected source as described in Sec.  
63.480'' for each occurrence of the phrase ``For each source as defined 
in Sec.  63.101''.
    (2) Substitute ``beginning no later than the compliance dates 
specified in Sec.  63.481(n)'' for each occurrence of the phrase 
``beginning no later than the compliance dates specified in Sec.  
63.100(k)(10)''.
    (3) Substitute ``owners and operators of affected sources as 
described in Sec.  63.480'' for each occurrence of the phrase ``owners 
and operators of sources as defined in Sec.  63.101''.
    (4) Substitute ``Sec.  63.508'' for each occurrence of ``Sec.  
63.108''.
    (y) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(o), if the Group 1 or Group 2 continuous front-end process vent 
contains chloroprene such that it is considered to be in chloroprene 
service, as defined in Sec.  63.482, then the owner or operator must 
comply with the requirements of paragraphs (y)(1) through (4) of this 
section in addition to all other applicable requirements specified in 
Sec.  63.483 and elsewhere in this section.
    (1) Reduce emissions of chloroprene by venting emissions through a 
closed vent system to a non-flare control device that reduces 
chloroprene by greater than or equal to 98 percent by weight, or to a 
concentration less than 1 ppmv for each process vent or to less than 5 
pounds per year for all combined process vents within the process. If a 
combustion device is used, the chloroprene concentration of 1 ppmv must 
be corrected to 3 percent oxygen.
    (2) To demonstrate compliance with the emission limits specified in 
paragraph (y)(1) of this section for continuous front-end process vents 
in chloroprene service, owners and operators must meet the requirements 
specified in Sec.  63.510.
    (3) Owners and operators must keep the records specified in 
paragraphs (y)(3)(i) and (y)(3)(ii) of this section in addition to 
those records specified elsewhere in this section.

[[Page 43245]]

    (i) For process vents, include all uncontrolled, undiluted 
chloroprene concentration measurements, and the calculations used to 
determine the total uncontrolled chloroprene mass emission rate for the 
sum of all vent gas streams.
    (ii) The owner or operator must keep records of all periods during 
which operating values are outside of the applicable operating limits 
specified in Sec.  63.510(b)(4) through (6) when regulated material is 
being routed to the non-flare control device. The record must specify 
the operating parameter, the applicable limit, and the highest (for 
maximum operating limits) or lowest (for minimum operating limits) 
value recorded during the period.
    (4) The Periodic Report must include the records for the periods 
specified in paragraph (y)(3)(ii) of this section. Indicate the start 
date, start time and duration in hours for each period.
    (z) For continuous front-end process vents that are in chloroprene 
service and subject to the requirements of Sec.  63.510, the 
requirements in 40 CFR 63.113(k)(4) do not apply. Instead, in addition 
to complying with the requirements in paragraphs 40 CFR 63.113(k)(1) 
through (3), for continuous front-end process vents that are in 
chloroprene service and subject to the requirements of Sec.  63.510 
that are designated as maintenance vents, owners and operators may not 
release more than 1.0 tons of chloroprene from all maintenance vents 
combined (i.e., including maintenance vents subject to this paragraph 
(z), Sec.  63.487(i)(4), or Sec.  63.494(a)(7)(iii)) per any 
consecutive 12-month period. The owner or operator must keep monthly 
records of the quantity in tons of chloroprene released from each 
maintenance vent and include a description of the method used to 
estimate this quantity.

0
126. Amend Sec.  63.487 by:
0
a. Revising and republishing paragraphs (a) and (b);
0
b. Revising paragraphs (c) introductory text, (c)(1) and (e)(1)(iii);
0
c. Adding paragraph (e)(1)(iv);
0
d. Revising paragraphs (f) introductory text and (g) introductory text; 
and
0
e. Adding paragraphs (i) and (j).
    The revisions, additions and republications read as follows:


Sec.  63.487  Batch front-end process vents--reference control 
technology.

    (a) Batch front-end process vents. Except as specified in paragraph 
(j) of this section, the owner or operator of an affected source with a 
Group 1 batch front-end process vent, as determined using the 
procedures in Sec.  63.488, shall comply with the requirements of 
either paragraph (a)(1) or (a)(2) of this section, and paragraph (a)(3) 
of this section. Compliance may be based on either organic HAP or TOC.
    (1) For each batch front-end process vent, reduce organic HAP 
emissions using a flare.
    (i) Except as specified in paragraph (a)(1)(iii) of this section, 
the owner or operator of the affected sources shall comply with the 
requirements of Sec.  63.504(c) for the flare.
    (ii) Halogenated batch front-end process vents, as defined in Sec.  
63.482, shall not be vented to a flare.
    (iii) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (a)(1)(i) of this section no longer applies and 
instead the owner or operator of the affected sources must comply with 
Sec.  63.508 for the flare.
    (2) For each batch front-end process vent, reduce organic HAP 
emissions for the batch cycle by 90 weight percent using a control 
device. Owners or operators may achieve compliance with this paragraph 
through the control of selected batch emission episodes or the control 
of portions of selected batch emission episodes. Documentation 
demonstrating how the 90 weight percent emission reduction is achieved 
is required by Sec.  63.490(c)(2).
    (3) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), for each batch front-end process vent that contains 
chlorine, HCl, or any other chlorinated compound, reduce emissions of 
dioxins and furans (toxic equivalency basis) to a concentration of 
0.054 nanograms per standard cubic meter on a dry basis corrected to 3 
percent oxygen.
    (b) Aggregate batch vent streams. Except as specified in paragraph 
(j) of this section the owner or operator of an aggregate batch vent 
stream that contains one or more Group 1 batch front-end process vents 
shall comply with the requirements of either paragraph (b)(1) or (b)(2) 
of this section, and paragraph (b)(3) of this section. Compliance may 
be based on either organic HAP or TOC.
    (1) For each aggregate batch vent stream, reduce organic HAP 
emissions using a flare.
    (i) Except as specified in paragraph (b)(1)(iii) of this section, 
the owner or operator of the affected source shall comply with the 
requirements of Sec.  63.504(c) for the flare.
    (ii) Halogenated aggregate batch vent streams, as defined in Sec.  
63.482, shall not be vented to a flare.
    (iii) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (b)(1)(i) of this section no longer applies and 
instead the owner or operator of the affected source must comply with 
Sec.  63.508 for the flare.
    (2) For each aggregate batch vent stream, reduce organic HAP 
emissions by 90 weight percent or to a concentration of 20 ppmv, on a 
continuous basis using a control device. For purposes of complying with 
the 20 ppmv outlet concentration standard, the outlet concentration 
shall be calculated on a dry basis. When a combustion device is used 
for purposes of complying with the 20 ppmv outlet concentration 
standard, the concentration shall be corrected to 3 percent oxygen if 
supplemental combustion air is used to combust the emissions. If 
supplemental combustion air is not used, a correction to 3 percent 
oxygen is not required.
    (3) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), for each aggregate batch vent stream that contains chlorine, 
HCl, or any other chlorinated compound, reduce emissions of dioxins and 
furans (toxic equivalency basis) to a concentration of 0.054 nanograms 
per standard cubic meter on a dry basis corrected to 3 percent oxygen
    (c) Halogenated emissions. Halogenated Group 1 batch front-end 
process vents, halogenated aggregate batch vent streams, and 
halogenated continuous front-end process vents that are combusted as 
part of complying with paragraph (a)(2), (a)(3), (b)(2), or (b)(3) of 
this section, shall be controlled according to either paragraph (c)(1) 
or (c)(2) of this section.
    (1) If a combustion device is used to comply with paragraph (a)(2), 
(a)(3), (b)(2), or (b)(3) of this section for a halogenated batch 
front-end process vent or halogenated aggregate batch vent stream, the 
emissions exiting the combustion device shall be ducted to a halogen 
reduction device that reduces overall emissions of hydrogen halides and 
halogens by at least 99 percent before discharge to the atmosphere.
* * * * *
    (e) * * *
    (1) * * *
    (iii) Except as specified in paragraph (e)(1)(iv) of this section, 
the batch front-end process vent or aggregate batch vent stream is 
combined with a continuous front-end process vent stream prior to being 
routed to a recovery device. In this paragraph (e)(1)(iii), the 
definition

[[Page 43246]]

of recovery device as it relates to continuous front-end process vents 
shall be used. Furthermore, the combined vent stream discussed in this 
paragraph (e)(1)(iii) shall be subject to Sec.  63.485(o)(2).
    (iv) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (e)(1)(iii) of this section no longer applies.
* * * * *
    (f) Group 2 batch front-end process vents with annual emissions 
greater than or equal to the level specified in Sec.  63.488(d). Except 
as specified in paragraph (j) of this section, the owner or operator of 
a Group 2 batch front-end process vent with annual emissions greater 
than or equal to the level specified in Sec.  63.488(d) shall comply 
with the provisions of paragraph (f)(1), (f)(2), or (h) of this 
section.
* * * * *
    (g) Group 2 batch front-end process vents with annual emissions 
less than the level specified in Sec.  63.488(d). Except as specified 
in paragraph (j) of this section, the owner or operator of a Group 2 
batch front-end process vent with annual organic HAP emissions less 
than the level specified in Sec.  63.488(d), shall comply with 
paragraph (g)(1), (g)(2), (g)(3), or (g)(4) of this section.
* * * * *
    (i) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), an owner or operator may designate a batch front-end process 
vent as a maintenance vent if the vent is only used as a result of 
startup, shutdown, maintenance, or inspection of equipment where 
equipment is emptied, depressurized, degassed, or placed into service. 
The owner or operator must comply with the applicable requirements in 
paragraphs (i)(1) through (i)(4) of this section for each maintenance 
vent. Any vent designated as a maintenance vent is only subject to the 
maintenance vent provisions in this paragraph (i) and the associated 
recordkeeping and reporting requirements in Sec.  63.491(h) and Sec.  
63.492(g), respectively. The owner or operator does not need to 
designate a maintenance vent as a Group 1 or Group 2 batch front-end 
process vent nor identify maintenance vents in a Notification of 
Compliance Status report.
    (1) Prior to venting to the atmosphere, remove process liquids from 
the equipment as much as practical and depressurize the equipment to 
either: A flare meeting the requirements of Sec.  63.508, as 
applicable, or using any combination of a non-flare combustion, 
recovery, and/or recapture device meeting the requirements in paragraph 
(a)(2) of this section until one of the following conditions, as 
applicable, is met.
    (i) The concentration of the vapor in the equipment served by the 
maintenance vent is less than 10 percent of its lower explosive limit 
(LEL) and has an outlet concentration less than or equal to 20 ppmv 
hydrogen halide and halogen HAP.
    (ii) If there is no ability to measure the concentration of the 
vapor in the equipment based on the design of the equipment, the 
pressure in the equipment served by the maintenance vent is reduced to 
5 pounds per square inch gauge (psig) or less. Upon opening the 
maintenance vent, active purging of the equipment cannot be used until 
the concentration of the vapors in the maintenance vent (or inside the 
equipment if the maintenance is a hatch or similar type of opening) is 
less than 10 percent of its LEL.
    (iii) The equipment served by the maintenance vent contains less 
than 50 pounds of total volatile organic compounds (VOC).
    (iv) If, after applying best practices to isolate and purge 
equipment served by a maintenance vent, none of the applicable 
criterion in paragraphs (i)(1)(i) through (i)(1)(iii) of this section 
can be met prior to installing or removing a blind flange or similar 
equipment blind, then the pressure in the equipment served by the 
maintenance vent must be reduced to 2 psig or less before installing or 
removing the equipment blind. During installation or removal of the 
equipment blind, active purging of the equipment may be used provided 
the equipment pressure at the location where purge gas is introduced 
remains at 2 psig or less.
    (2) Except for maintenance vents complying with the alternative in 
paragraph (i)(1)(iii) of this section, the owner or operator must 
determine the concentration or, if applicable, equipment pressure using 
process instrumentation or portable measurement devices and follow 
procedures for calibration and maintenance according to manufacturer's 
specifications.
    (3) For maintenance vents complying with the alternative in 
paragraph (i)(1)(iii) of this section, the owner or operator must 
determine mass of VOC in the equipment served by the maintenance vent 
based on the equipment size and contents after considering any contents 
drained or purged from the equipment. Equipment size may be determined 
from equipment design specifications. Equipment contents may be 
determined using process knowledge.
    (4) In addition to complying with the requirements in paragraphs 
(i)(1) through (i)(3) of this section, for batch front-end process 
vents that are in chloroprene service and subject to the requirements 
of Sec.  63.510 that are designated as maintenance vents, owners and 
operators may not release more than 1.0 tons of chloroprene from all 
maintenance vents combined (i.e., including maintenance vents subject 
to this paragraph (i)(4), Sec.  63.485(z), or Sec.  63.494(a)(7)(iii)) 
per any consecutive 12-month period. The owner or operator must keep 
monthly records of the quantity in tons of chloroprene released from 
each maintenance vent and include a description of the method used to 
estimate this quantity.
    (j) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(o), if the Group 1 or Group 2 batch front-end process vent 
contains chloroprene such that it is considered to be in chloroprene 
service, as defined in Sec.  63.482, then the owner or operator must 
comply with the requirements of paragraphs (j)(1) through (j)(4) of 
this section in addition to all other applicable requirements specified 
in Sec.  63.483 and elsewhere in this section.
    (1) Reduce emissions of chloroprene by venting emissions through a 
closed vent system to a non-flare control device that reduces 
chloroprene by greater than or equal to 98 percent by weight, or to a 
concentration less than 1 ppmv for each process vent or to less than 5 
pounds per year for all combined process vents within the process. If a 
combustion device is used, the chloroprene concentration of 1 ppmv must 
be corrected to 3 percent oxygen.
    (2) To demonstrate compliance with the emission limits specified in 
paragraph (j)(1) of this section for batch front-end process vents in 
chloroprene service, owners and operators must meet the requirements 
specified in Sec.  63.510.
    (3) Owners and operators must keep the records specified in 
paragraphs (j)(3)(i) and (j)(3)(ii) of this section in addition to 
those records specified elsewhere in this section.
    (i) For process vents, include all uncontrolled, undiluted 
chloroprene concentration measurements, and the calculations used to 
determine the total uncontrolled chloroprene mass emission rate for the 
sum of all vent gas streams.
    (ii) The owner or operator must keep records of all periods during 
which operating values are outside of the

[[Page 43247]]

applicable operating limits specified in Sec.  63.510(b)(4) through (6) 
when regulated material is being routed to the non-flare control 
device. The record must specify the operating parameter, the applicable 
limit, and the highest (for maximum operating limits) or lowest (for 
minimum operating limits) value recorded during the period.
    (4) The Periodic Report must include the records of periods 
specified in paragraph (j)(3)(ii) of this section. Indicate the start 
date, start time and duration in hours for each period.

0
127. Amend Sec.  63.488 by:
0
a. Revising paragraphs (b)(5)(iii), (d), and (e) introductory text,
0
b. Adding paragraph (e)(4); and
0
c. Revising paragraphs (f) and (g).
    The revisions and addition read as follows:


Sec.  63.488  Methods and procedures for batch front-end process vent 
group determination.

* * * * *
    (b) * * *
    (5) * * *
    (iii) Method 18 or Method 25A of appendices A-6 and A-7 to 40 CFR 
part 60, respectively, must be used to determine the concentration of 
TOC or organic HAP, as appropriate. ASTM D6420-18 (incorporated by 
reference, see Sec.  63.14) may also be used in lieu of Method 18, if 
the target compounds are all known and are all listed in Section 1.1 of 
ASTM D6420-18 as measurable; ASTM D6420-18 must not be used for methane 
and ethane; and ASTM D6420-18 may not be used as a total VOC method. 
The use of Method 25A must conform with the requirements in paragraphs 
(b)(5)(iii)(A) and (B) of this section.
    (A) The organic HAP used as the calibration gas for Method 25A of 
appendix A-7 to 40 CFR part 60 must be the single organic HAP 
representing the largest percent by volume of the emissions.
* * * * *
    (d) Minimum emission level exemption. (1) Except as specified in 
paragraph (d)(2) of this section, a batch front-end process vent with 
annual emissions of TOC or organic HAP less than 11,800 kg/yr is 
considered a Group 2 batch front-end process vent and the owner or 
operator of that batch front-end process vent shall comply with the 
requirements in Sec.  63.487(f) or (g). Annual emissions of TOC or 
organic HAP are determined at the exit of the batch unit operation, as 
described in paragraph (a)(2) of this section, and are determined as 
specified in paragraph (b) of this section. The owner or operator of 
that batch front-end process vent is not required to comply with the 
provisions in paragraphs (e) through (g) of this section.
    (2) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (d)(1) of this section no longer applies and 
instead the collection of all batch front-end process vents with 
combined total annual emissions of TOC or organic HAP less than 4,536 
kg/yr (10,000 lb/yr) are considered Group 2 batch front-end process 
vents. Annual emissions of TOC or organic HAP are determined at the 
exit of each batch unit operation, as described in paragraph (a)(2) of 
this section, and are determined as specified in paragraph (b) of this 
section.
    (e) Determination of average batch vent flow rate and annual 
average batch vent flow rate. Except as specified in paragraph (e)(4) 
of this section, the owner or operator shall determine the average 
batch vent flow rate for each batch emission episode in accordance with 
one of the procedures provided in paragraphs (e)(1) through (e)(2) of 
this section. The annual average batch vent flow rate for a batch 
front-end process vent shall be calculated as specified in paragraph 
(e)(3) of this section.
* * * * *
    (4) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (e) of this section no longer applies.
    (f) Determination of cutoff flow rate. (1) Except as specified in 
paragraph (f)(2) of this section, for each batch front-end process 
vent, the owner or operator shall calculate the cutoff flow rate using 
Equation 15.
Equation 15 to Paragraph (f)
CFR=(0.00437)(AE)-51.6 [Eq. 15]

Where:

CFR = Cutoff flow rate, scmm.
AE = Annual TOC or organic HAP emissions, as determined in paragraph 
(b)(8) of this section, kg/yr.

    (2) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (f) of this section no longer applies.
    (g) Group 1/Group 2 status determination. Except as specified in 
paragraph (g)(3) of this section, the owner or operator shall compare 
the cutoff flow rate, calculated in accordance with paragraph (f) of 
this section, with the annual average batch vent flow rate, determined 
in accordance with paragraph (e)(3) of this section. The group 
determination status for each batch front-end process vent shall be 
made using the criteria specified in paragraphs (g)(1) and (g)(2) of 
this section.
    (1) If the cutoff flow rate is greater than or equal to the annual 
average batch vent flow rate of the stream, the batch front-end process 
vent is classified as a Group 1 batch front-end process vent.
    (2) If the cutoff flow rate is less than the annual average batch 
vent flow rate of the stream, the batch front-end process vent is 
classified as a Group 2 batch front-end process vent.
    (3) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (g) of this section no longer applies.
* * * * *

0
128. Amend Sec.  63.489 by:
0
a. Revising paragraphs (a) introductory text, (b) introductory text, 
(b)(2), and (b)(7);
0
b. Adding paragraphs (b)(9), (10) and (11);
0
c. Revising paragraph (d) introductory text and adding paragraph 
(d)(3); and
0
d. Revising paragraph (e)(1)(i), and adding paragraph (e)(1)(iii).
    The revisions and additions read as follows:


Sec.  63.489  Batch front-end process vents--monitoring equipment.

    (a) General requirements. Each owner or operator of a batch front-
end process vent or aggregate batch vent stream that uses a control 
device to comply with the requirements in Sec.  63.487(a)(2) or (3) or 
Sec.  63.487(b)(2) or (3) shall install the monitoring equipment 
specified in paragraph (b) of this section. All monitoring equipment 
shall be installed, calibrated, maintained, and operated according to 
the manufacturer's specifications or other written procedures that 
provide adequate assurance that the equipment would reasonably be 
expected to monitor accurately.
* * * * *
    (b) Batch front-end process vent and aggregate batch vent stream 
monitoring equipment. The monitoring equipment specified in paragraphs 
(b)(1) through (b)(11) of this section shall be installed as specified 
in paragraph (a) of this section. The parameters to be monitored are 
specified in Table 6 of this subpart.
* * * * *
    (2) Where a flare is used, except as specified in paragraph (b)(9) 
of this section, a device (including, but not limited to, a 
thermocouple, ultra-violet beam sensor, or infrared sensor) capable of 
continuously detecting the presence of a pilot flame is required.
* * * * *

[[Page 43248]]

    (7) Except as specified in paragraph (b)(10) of this section, where 
a carbon adsorber is used, an integrating regeneration steam flow, 
nitrogen flow, or pressure monitoring device having an accuracy of 
10 percent of the flow rate, level, or pressure, or better, 
capable of recording the total regeneration steam flow or nitrogen 
flow, or pressure (gauge or absolute) for each regeneration cycle; and 
a carbon bed temperature monitoring device, capable of recording the 
carbon bed temperature after each regeneration and within 15 minutes of 
completing any cooling cycle are required.
* * * * *
    (9) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (b)(2) of this section no longer applies and 
instead the owner or operator of the affected source must comply with 
Sec.  63.508 for the flare.
    (10) Beginning no later than the compliance dates specified in 
Sec.  63.481(n), if the owner or operator vents emissions through a 
closed vent system to an adsorber(s) that cannot be regenerated or a 
regenerative adsorber(s) that is regenerated offsite, then the owner or 
operator must install a system of two or more adsorber units in series 
and comply with the requirements specified in paragraphs (b)(10)(i) 
through (b)(10)(iii) of this section.
    (i) Conduct an initial performance test or design evaluation of the 
adsorber and establish the breakthrough limit and adsorber bed life.
    (ii) Monitor the HAP or total organic compound (TOC) concentration 
through a sample port at the outlet of the first adsorber bed in series 
according to the schedule in paragraph (b)(10)(iii)(B) of this section. 
The owner or operator must measure the concentration of HAP or TOC 
using either a portable analyzer, in accordance with Method 21 of 40 
CFR part 60, appendix A-7 using methane, propane, isobutylene, or the 
primary HAP being controlled as the calibration gas or Method 25A of 40 
CFR part 60, appendix A-7 using methane, propane, or the primary HAP 
being controlled as the calibration gas.
    (iii) Comply with paragraph (b)(10)(iii)(A) of this section, and 
comply with the monitoring frequency according to paragraph 
(b)(10)(iii)(B) of this section.
    (A) The first adsorber in series must be replaced immediately when 
breakthrough, as defined in Sec.  63.482, is detected between the first 
and second adsorber. The original second adsorber (or a fresh canister) 
will become the new first adsorber and a fresh adsorber will become the 
second adsorber. For purposes of this paragraph, ``immediately'' means 
within 8 hours of the detection of a breakthrough for adsorbers of 55 
gallons or less, and within 24 hours of the detection of a breakthrough 
for adsorbers greater than 55 gallons. The owner or operator must 
monitor at the outlet of the first adsorber within 3 days of 
replacement to confirm it is performing properly.
    (B) Based on the adsorber bed life established according to 
paragraph (b)(10)(i) of this section and the date the adsorbent was 
last replaced, conduct monitoring to detect breakthrough at least 
monthly if the adsorbent has more than 2 months of life remaining, at 
least weekly if the adsorbent has between 2 months and 2 weeks of life 
remaining, and at least daily if the adsorbent has 2 weeks or less of 
life remaining.
    (11) Where sorbent injection is used, the following monitoring 
equipment is required for the sorbent injection system:
    (i) A sorbent injection rate monitoring device (e.g., weigh belt, 
weigh hopper, hopper flow measurement device) installed in a position 
that provides a representative measurement equipped with a continuous 
recorder to monitor the sorbent injection rate; and
    (ii) A flow measurement device equipped with a continuous recorder 
to monitor the carrier gas flow rate.
* * * * *
    (d) Monitoring of bypass lines. The owner or operator of a batch 
front-end process vent or aggregate batch vent stream using a vent 
system that contains bypass lines that could divert emissions away from 
a control device used to comply with Sec.  63.487(a) or Sec.  63.487(b) 
shall comply with either paragraph (d)(1) or (d)(2), and (d)(3) of this 
section. Except as specified in paragraph (d)(3) of this section, 
equipment such as low leg drains, high point bleeds, analyzer vents, 
open-ended valves or lines, and pressure relief valves needed for 
safety purposes are not subject to this paragraph (d).
* * * * *
    (3) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n):
    (i) The use of a bypass line at any time on a closed vent system to 
divert emissions (subject to the emission standards in Sec.  63.487) to 
the atmosphere or to a control device not meeting the requirements 
specified in this subpart is an emissions standards violation.
    (ii) The last sentence in paragraph (d) of this section no longer 
applies. Instead, the exemptions specified in paragraph (d)(3)(ii)(A) 
and (d)(3)(ii)(B) of this section apply.
    (A) Except for pressure relief devices subject to Sec.  
63.165(e)(4) of subpart H of this part, equipment such as low leg 
drains and equipment subject to the requirements of subpart H of this 
part are not subject to this paragraph (d).
    (B) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in 40 CFR 60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as 40 CFR 60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (d) of this section.
    (e) * * *
    (1) * * *
    (i) For batch front-end process vents using a control device to 
comply with Sec.  63.487(a)(2), the established level shall reflect the 
control efficiency established as part of the most recent compliance 
demonstration specified in Sec.  63.490(c)(2).
* * * * *
    (iii) For batch front-end process vents using a control device to 
comply with Sec.  63.487(a)(3) and aggregate batch vent streams using a 
control device to comply with Sec.  63.487 (b)(3), the established 
level shall reflect the level of control established as part of the 
most recent compliance demonstration specified in Sec.  63.490(g).
* * * * *

0
129. Amend Sec.  63.490 by revising paragraphs (a), (c)(1)(i)(D), and 
(e)(1), and adding paragraph (g) as follows:


Sec.  63.490  Batch front-end process vents--performance test methods 
and procedures to determine compliance.

    (a) Use of a flare. (1) Except as specified in paragraph (a)(2) of 
this section, when a flare is used to comply with Sec.  63.487(a)(1) or 
(b)(1), the owner or operator of an affected source shall comply with 
Sec.  63.504(c).
    (2) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (a)(1) of this section no longer applies and 
instead the owner or operator of the affected source must comply with 
Sec.  63.508 for the flare.
* * * * *
    (c) * * *
    (1) * * *
    (i) * * *
    (D) Method 18 or Method 25A of appendices A-6 and A-7 to 40 CFR 
part 60, respectively must be used to determine the concentration of 
organic HAP or TOC, as appropriate. ASTM

[[Page 43249]]

D6420-18 (incorporated by reference, see Sec.  63.14) may also be used 
in lieu of Method 18, if the target compounds are all known and are all 
listed in Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 
must not be used for methane and ethane; and ASTM D6420-18 may not be 
used as a total VOC method. Alternatively, any other method or data 
that has been validated according to the applicable procedures in 
Method 301 of appendix A to this part may be used. The use of Method 
25A must conform with the requirements in paragraphs (c)(1)(i)(D)(1) 
and (2) of this section.
    (1) The organic HAP used as the calibration gas for Method 25A 
appendix A-7 to 40 CFR part 60 must be the single organic HAP 
representing the largest percent by volume of the emissions.
    (2) The use of Method 25A appendix A-7 to 40 CFR part 60 is 
acceptable if the response from the high-level calibration gas is at 
least 20 times the standard deviation of the response from the zero 
calibration gas when the instrument is zeroed on the most sensitive 
scale
* * * * *
    (e) * * *
    (1) For the purposes of this subpart, when the provisions of Sec.  
63.116(c) specify that Method 18 of appendix A-6 to 40 CFR part 60 must 
be used, Method 18 or Method 25A of appendix A-7 to 40 CFR part 60 may 
be used. ASTM D6420-18 (incorporated by reference, see Sec.  63.14) may 
also be used in lieu of Method 18, if the target compounds are all 
known and are all listed in Section 1.1 of ASTM D6420-18 as measurable; 
ASTM D6420-18 must not be used for methane and ethane; and ASTM D6420-
18 may not be used as a total VOC method. The use of Method 25A of 
appendix A-7 to 40 CFR part 60 must conform with the requirements in 
paragraphs (e)(1)(i) and (ii) of this section.
    (i) The organic HAP used as the calibration gas for Method 25A of 
appendix A-7 to 40 CFR part 60 must be the single organic HAP 
representing the largest percent by volume of the emissions.
    (ii) The use of Method 25A of appendix A-7 to 40 CFR part 60 is 
acceptable if the response from the high-level calibration gas is at 
least 20 times the standard deviation of the response from the zero 
calibration gas when the instrument is zeroed on the most sensitive 
scale.
* * * * *
    (g) Testing for compliance with Sec.  63.487(a)(3) and (b)(3) 
[dioxins and furans]. Except as specified in paragraph (g)(7) of this 
section, an owner or operator complying with Sec.  63.487(a)(3) and/or 
(b)(3) must conduct a performance test using the procedures in 
paragraphs (g)(1) through (6) of this section. Conduct subsequent 
performance tests no later than 60 calendar months after the previous 
performance test.
    (1) The performance test must consist of three test runs. Collect 
at least 3 dry standard cubic meters of gas per test run.
    (2) Use Method 1 or 1A of appendix A-1 to 40 CFR part 60 to select 
the sampling sites at the sampling location. The sampling location must 
be at the outlet of the final control device.
    (3) Determine the gas volumetric flowrate using Method 2, 2A, 2C, 
or 2D of appendix A-2 to 40 CFR part 60.
    (4) Use Method 4 of appendix A-3 to 40 CFR part 60 to convert the 
volumetric flowrate to a dry basis.
    (5) Measure the concentration of each tetra- through octa-
chlorinated dioxin and furan congener emitted using Method 23 of 
appendix A-7 to 40 CFR part 60.
    (i) For each dioxin and furan congener, multiply the congener 
concentration by its corresponding toxic equivalency factor specified 
in table 10 to this subpart. For determination of toxic equivalency, 
zero may be used for congeners with a concentration less than the 
estimated detection limit (EDL). For congeners with estimated maximum 
pollutant concentration (EMPC) results, if the value is less than the 
EDL, zero may be used. Otherwise, the EMPC value must be used in the 
calculation of toxic equivalency.
    (ii) Sum the products calculated in accordance with paragraph 
(g)(5)(i) of this section to obtain the total concentration of dioxins 
and furans emitted in terms of toxic equivalency.
    (6) The concentration of dioxins and furans shall be corrected to 3 
percent oxygen. Use Method 3A of appendix A-2 to 40 CFR part 60 or the 
manual method in ANSI/ASME PTC 19.10-1981 (incorporated by reference, 
see Sec.  63.14) to determine the oxygen concentration (%O2d). The 
oxygen concentration must be determined concurrently with Method 23 of 
appendix A-7 to 40 CFR part 60. The concentration corrected to 3 
percent oxygen (Cc) shall be computed using the following equation:
[GRAPHIC] [TIFF OMITTED] TR16MY24.064

Where:

Cc = Concentration of dioxins and furans corrected to 3 
percent oxygen, dry basis, nanograms per standard cubic meter.
Cm = Concentration of dioxins and furans, dry basis, 
nanograms per standard cubic meter.
%O2d = Concentration of oxygen, dry basis, percent by 
volume.

    (7) An owner or operator is not required to conduct a performance 
test when either a boiler or process heater burning hazardous waste, or 
hazardous waste incinerator, is used for which the owner or operator:
    (i) Has been issued a final permit under 40 CFR part 270 and 
complies with the requirements of 40 CFR part 266, subpart H;
    (ii) Has certified compliance with the interim status requirements 
of 40 CFR part 266, subpart H;
    (iii) Meets the requirement specified in paragraph (g)(7)(v) of 
this section, and has submitted a Notification of Compliance under 
Sec.  63.1207(j) and complies with the requirements of subpart EEE of 
this part; or
    (iv) Meets the requirement specified in paragraph (g)(7)(v) of this 
section, complies with subpart EEE of this part, and will submit a 
Notification of Compliance under Sec.  63.1207(j) by the date the owner 
or operator would have been required to submit the initial performance 
test report for this subpart.
    (v) The owner and operator may not waive performance testing 
pursuant to Sec.  63.1207(d)(4) and each performance test required by 
Sec.  63.1207(d) must show compliance with the dioxins and furans 
emission limit specified in Sec.  63.487(a)(3) and (b)(3), as 
applicable.

0
130. Amend Sec.  63.491 by:
0
a. Revising paragraph (b)(3) introductory text;
0
b. Adding paragraphs (b)(3)(iv) and (b)(6);
0
c. Revising and republishing paragraph (d)(1);

[[Page 43250]]

0
d. Revising paragraphs (e)(3) and (e)(4) introductory text;
0
e. Adding paragraph (e)(6);
0
f. Revising paragraph (f)(3); and
0
g. Adding paragraph (h).
    The revisions, additions and republication read as follows:


Sec.  63.491  Batch front-end process vents--recordkeeping 
requirements.

* * * * *
    (b) * * *
    (3) Except as specified in paragraph (b)(3)(iv) of this section, 
when using a flare to comply with Sec.  63.487(a)(1):
* * * * *
    (iv) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraphs (b)(3)(i) through (b)(3)(iii) of this section no 
longer apply and instead the owner or operator of the affected source 
must keep the records specified in Sec.  63.108(m) of subpart F of this 
part and Sec.  63.508, readily accessible when using a flare to comply 
with Sec.  63.487(a)(1).
* * * * *
    (6) Records of the dioxins and furans concentration, as determined 
in Sec.  63.490(g).
* * * * *
    (d) * * *
    (1) The owner or operator of a Group 2 batch front-end process vent 
required to comply with Sec.  63.487(g) shall keep the following 
records readily accessible:
    (i) Except as specified in paragraph (d)(1)(iii) of this section, 
records designating the established batch mass input limitation 
required by Sec.  63.487(g)(1) and specified in Sec.  63.490(f).
    (ii) Records specifying the mass of HAP or material charged to the 
batch unit operation.
    (iii) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (d)(1)(i) of this section no longer applies.
* * * * *
    (e) * * *
    (3) Except as specified in paragraph (e)(6) of this section, hourly 
records of whether the flow indicator for bypass lines specified under 
Sec.  63.489(d)(1) was operating and whether a diversion was detected 
at any time during the hour. Also, records of the times of all periods 
when the vent is diverted from the control device, or the flow 
indicator specified in Sec.  63.489(d)(1) is not operating.
    (4) Except as specified in paragraph (e)(6) of this section, where 
a seal or closure mechanism is used to comply with Sec.  63.489(d)(2), 
hourly records of whether a diversion was detected at any time are not 
required.
* * * * *
    (6) For each flow event from a bypass line subject to the 
requirements in Sec.  63.489(d) for each affected source as described 
in Sec.  63.480, beginning no later than the compliance dates specified 
in Sec.  63.481(n), the owner or operator must also maintain records 
sufficient to determine whether or not the detected flow included flow 
requiring control. For each flow event from a bypass line requiring 
control that is released either directly to the atmosphere or to a 
control device not meeting the requirements in this subpart, the owner 
or operator must include an estimate of the volume of gas, the 
concentration of organic HAP in the gas and the resulting emissions of 
organic HAP that bypassed the control device using process knowledge 
and engineering estimates.
    (f) * * *
    (3) For demonstrating compliance with the monitoring of bypass 
lines as specified in Sec.  63.489(d), records as specified in 
paragraph (e)(3) or (4) of this section, and (e)(6) of this section as 
appropriate.
* * * * *
    (h) Maintenance vent compliance records for batch front-end process 
vents. For each maintenance vent opening subject to the requirements of 
Sec.  63.487(i), owners and operators must keep the applicable records 
specified in paragraphs (h)(1) through (5) of this section.
    (1) Owners and operators must maintain standard site procedures 
used to deinventory equipment for safety purposes (e.g., hot work or 
vessel entry procedures) to document the procedures used to meet the 
requirements in Sec.  63.487(i). The current copy of the procedures 
must be retained and available on-site at all times. Previous versions 
of the standard site procedures, as applicable, must be retained for 
five years.
    (2) If complying with the requirements of Sec.  63.487(i)(1)(i), 
and the concentration of the vapor at the time of the vessel opening 
exceeds 10 percent of its LEL, identification of the maintenance vent, 
the process units or equipment associated with the maintenance vent, 
the date of maintenance vent opening, and the concentration of the 
vapor at the time of the vessel opening.
    (3) If complying with the requirements of Sec.  63.487(i)(1)(ii), 
and either the vessel pressure at the time of the vessel opening 
exceeds 5 psig or the concentration of the vapor at the time of the 
active purging was initiated exceeds 10 percent of its LEL, 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, the date of maintenance vent 
opening, the pressure of the vessel or equipment at the time of 
discharge to the atmosphere and, if applicable, the concentration of 
the vapors in the equipment when active purging was initiated.
    (4) If complying with the requirements of Sec.  63.487(i)(1)(iii), 
records of the estimating procedures used to determine the total 
quantity of VOC in the equipment and the type and size limits of 
equipment that contain less than 50 pounds of VOC at the time of 
maintenance vent opening. For each maintenance vent opening that 
contains greater than 50 pounds of VOC for which the deinventory 
procedures specified in paragraph (h)(1) of this section are not 
followed or for which the equipment opened exceeds the type and size 
limits established in the records specified in this paragraph (h)(4), 
records that identify the maintenance vent, the process units or 
equipment associated with the maintenance vent, the date of maintenance 
vent opening, and records used to estimate the total quantity of VOC in 
the equipment at the time the maintenance vent was opened to the 
atmosphere.
    (5) If complying with the requirements of Sec.  63.487(i)(1)(iv), 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, records documenting actions taken 
to comply with other applicable alternatives and why utilization of 
this alternative was required, the date of maintenance vent opening, 
the equipment pressure and concentration of the vapors in the equipment 
at the time of discharge, an indication of whether active purging was 
performed and the pressure of the equipment during the installation or 
removal of the blind if active purging was used, the duration the 
maintenance vent was open during the blind installation or removal 
process, and records used to estimate the total quantity of VOC in the 
equipment at the time the maintenance vent was opened to the atmosphere 
for each applicable maintenance vent opening.

0
131. Amend Sec.  63.492 by revising paragraph (f) and adding paragraph 
(g) to read as follows:


Sec.  63.492  Batch front-end process vents--reporting requirements.

* * * * *
    (f) Owners or operators of affected sources complying with Sec.  
63.489(d),

[[Page 43251]]

shall comply with paragraph (f)(1) or (2) of this section, as 
appropriate.
    (1) Submit reports of the times of all periods recorded under Sec.  
63.491(e)(3) when the batch front-end process vent is diverted away 
from the control device through a bypass line, with the next Periodic 
Report. Include the start date, start time and duration in hours of 
each period.
    (2) Submit reports of all occurrences recorded under Sec.  
63.491(e)(4) in which the seal mechanism is broken, the bypass line 
damper or valve position has changed, or the key to unlock the bypass 
line damper or valve was checked out, with the next Periodic Report. 
Include the start date, start time and duration in hours of each 
period.
    (g) For any maintenance vent release exceeding the applicable 
limits in Sec.  63.487(i)(1), the Periodic Report must include the 
information specified in paragraphs (g)(1) through (4) of this section. 
For the purposes of this reporting requirement, if an owner or operator 
complies with Sec.  63.487(i)(1)(iv), then the owner or operator must 
report each venting event conducted under those provisions and include 
an explanation for each event as to why utilization of this alternative 
was required.
    (1) Identification of the maintenance vent and the equipment served 
by the maintenance vent.
    (2) The date and time the maintenance vent was opened to the 
atmosphere.
    (3) The LEL in percent, vessel pressure in psig, or mass in pounds 
of VOC in the equipment, as applicable, at the start of atmospheric 
venting. If the 5 psig vessel pressure option in Sec.  63.487(i)(1)(ii) 
was used and active purging was initiated while the concentration of 
the vapor was 10 percent or greater of its LEL, also include the 
concentration of the vapors at the time active purging was initiated.
    (4) An estimate of the mass in pounds of organic HAP released 
during the entire atmospheric venting event.

0
132. Amend Sec.  63.494 by revising paragraph (a)(4) introductory text, 
adding paragraph (a)(7), revising paragraph (d), and adding paragraph 
(e) to read as follows:


Sec.  63.494  Back-end process provisions--residual organic HAP and 
emission limitations.

    (a) * * *
    (4) In addition to the requirements specified in paragraph (a)(7) 
of this section, the organic HAP emissions from back-end processes at 
affected sources producing butyl rubber, epichlorohydrin elastomer, 
neoprene, and nitrile butadiene rubber shall not exceed the limits 
determined in accordance with paragraphs (a)(4)(i) through (iv) of this 
section for any consecutive 12-month period. The specific limitation 
for each elastomer type shall be determined based on the calculation or 
the emissions level provided in paragraphs (a)(4)(i) through (iv) of 
this section divided by the base year elastomer product that leaves the 
stripping operation (or the reactor(s), if the plant has no 
stripper(s)). The limitation shall be calculated and submitted in 
accordance with Sec.  63.499(f)(1).
* * * * *
    (7) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(o), if the back-end process vent contains chloroprene such that 
it is considered to be in chloroprene service, as defined in Sec.  
63.482, then the owner or operator must comply with the requirements of 
paragraphs (a)(7)(i) through (iii) of this section in addition to all 
other applicable requirements specified in Sec.  63.483 and elsewhere 
in this section.
    (i) Reduce emissions of chloroprene by venting emissions through a 
closed vent system to a non-flare control device that reduces 
chloroprene by greater than or equal to 98 percent by weight, or to a 
concentration less than 1 ppmv for each process vent or to less than 5 
pounds per year for all combined process vents within the process. If a 
combustion device is used, the chloroprene concentration of 1 ppmv must 
be corrected to 3 percent oxygen.
    (ii) To demonstrate compliance with the emission limits specified 
in paragraph (a)(7)(i) of this section for back-end process vents in 
chloroprene service, owners and operators must meet the requirements 
specified in Sec.  63.510.
    (iii) An owner or operator may designate a back-end process vent in 
chloroprene service as a maintenance vent if the vent is only used as a 
result of startup, shutdown, maintenance, or inspection of equipment 
where equipment is emptied, depressurized, degassed, or placed into 
service; however, owners and operators may not release more than 1.0 
tons of chloroprene from all maintenance vents combined (i.e., 
including maintenance vents subject to this paragraph (a)(7)(iii), 
Sec.  63.485(z), or Sec.  63.487(i)(4)) per any consecutive 12-month 
period. The owner or operator must keep monthly records of the quantity 
in tons of chloroprene released from each maintenance vent and include 
a description of the method used to estimate this quantity.
* * * * *
    (d) Except as specified in paragraph (e) of this section, if the 
owner or operator complies with the residual organic HAP limitations in 
paragraph (a)(1) through (3) of this section using a flare, the owner 
or operator of an affected source shall comply with the requirements in 
Sec.  63.504(c).
    (e) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (d) of this section no longer applies and instead 
if the owner or operator complies with the residual organic HAP 
limitations in paragraph (a)(1) through (3) of this section using a 
flare, the owner or operator of the affected source must comply with 
Sec.  63.508 for the flare.

0
133. Amend Sec.  63.496 by revising paragraphs (b)(5)(iii) and 
(b)(7)(i) to read as follows:


Sec.  63.496  Back-end process provisions--procedures to determine 
compliance with residual organic HAP limitations using control or 
recovery devices.

* * * * *
    (b) * * *
    (5) * * *
    (iii) To determine the inlet and outlet total organic HAP 
concentrations, the owner or operator must use Method 18 or Method 25A 
of appendices A-6 and A-7 to 40 CFR part 60, respectively. ASTM D6420-
18 (incorporated by reference, see Sec.  63.14) may also be used in 
lieu of Method 18, if the target compounds are all known and are all 
listed in Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 
must not be used for methane and ethane; and ASTM D6420-18 may not be 
used as a total VOC method. Alternatively, any other method or data 
that has been validated according to the applicable procedures in 
Method 301 of appendix A to this part may be used. The minimum sampling 
time for each run must be in accordance with paragraph (b)(1) of this 
section, during which either an integrated sample or grab samples shall 
be taken. If grab sampling is used, then the samples must be taken at 
approximately equal intervals during the run, with the time between 
samples no greater than 15 minutes.
* * * * *
    (7) * * *
    (i) A flare. (A) Except as specified in paragraph (b)(7)(i)(B) of 
this section, the owner or operator shall demonstrate compliance as 
provided in Sec.  63.504(c).
    (B) For each affected source as described in Sec.  63.480, 
beginning no later

[[Page 43252]]

than the compliance dates specified in Sec.  63.481(n), paragraph 
(b)(7)(i)(A) of this section no longer applies and instead the owner or 
operator of the affected source must comply with Sec.  63.508 for the 
flare.
* * * * *

0
134. Amend Sec.  63.497 by revising paragraphs (a) introductory text, 
(a)(2) and (6), adding paragraphs (a)(7) and (8), revising paragraph 
(d) introductory text, and adding paragraph (d)(3) to read as follows:


Sec.  63.497  Back-end process provisions--monitoring provisions for 
control and recovery devices used to comply with residual organic HAP 
limitations.

    (a) An owner or operator complying with the residual organic HAP 
limitations in Sec.  63.494(a)(1) through (3) using control or recovery 
devices, or a combination of stripping and control or recovery devices, 
shall install the monitoring equipment specified in paragraphs (a)(1) 
through (7) of this section, as appropriate.
* * * * *
    (2) Where a flare is used, except as specified in paragraph (a)(7) 
of this section, a device (including, but not limited to, a 
thermocouple, ultra-violet beam sensor, or infrared sensor) capable of 
continuously detecting the presence of a pilot flame is required.
* * * * *
    (6) Except as specified in paragraph (a)(8) of this section, for a 
carbon adsorber, an integrating regeneration steam flow, nitrogen flow, 
or pressure monitoring device having an accuracy of at least 10 percent of the flow rate, level, or pressure, capable of 
recording the total regeneration steam flow or nitrogen flow, or 
pressure (gauge or absolute) for each regeneration cycle; and a carbon 
bed temperature monitoring device, capable of recording the carbon bed 
temperature after each regeneration and within 15 minutes of completing 
any cooling cycle are required.
    (7) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (a)(2) of this section no longer applies and 
instead the owner or operator of the affected source must comply with 
Sec.  63.508 for the flare.
    (8) Beginning no later than the compliance dates specified in Sec.  
63.481(n), if the owner or operator vents emissions through a closed 
vent system to an adsorber(s) that cannot be regenerated or a 
regenerative adsorber(s) that is regenerated offsite, then the owner or 
operator must install a system of two or more adsorber units in series 
and comply with the requirements specified in paragraphs (a)(8)(i) 
through (iii) of this section.
    (i) Conduct an initial performance test or design evaluation of the 
adsorber and establish the breakthrough limit and adsorber bed life.
    (ii) Monitor the HAP or total organic compound (TOC) concentration 
through a sample port at the outlet of the first adsorber bed in series 
according to the schedule in paragraph (a)(8)(iii)(B) of this section. 
The owner or operator must measure the concentration of HAP or TOC 
using either a portable analyzer, in accordance with Method 21 of 40 
CFR part 60, appendix A-7 using methane, propane, isobutylene, or the 
primary HAP being controlled as the calibration gas or Method 25A of 40 
CFR part 60, appendix A-7 using methane, propane, or the primary HAP 
being controlled as the calibration gas.
    (iii) Comply with paragraph (a)(8)(iii)(A) of this section, and 
comply with the monitoring frequency according to paragraph 
(a)(8)(iii)(B) of this section.
    (A) The first adsorber in series must be replaced immediately when 
breakthrough, as defined in Sec.  63.482, is detected between the first 
and second adsorber. The original second adsorber (or a fresh canister) 
will become the new first adsorber and a fresh adsorber will become the 
second adsorber. For purposes of this paragraph, ``immediately'' means 
within 8 hours of the detection of a breakthrough for adsorbers of 55 
gallons or less, and within 24 hours of the detection of a breakthrough 
for adsorbers greater than 55 gallons. The owner or operator must 
monitor at the outlet of the first adsorber within 3 days of 
replacement to confirm it is performing properly.
    (B) Based on the adsorber bed life established according to 
paragraph (a)(8)(i) of this section and the date the adsorbent was last 
replaced, conduct monitoring to detect breakthrough at least monthly if 
the adsorbent has more than 2 months of life remaining, at least weekly 
if the adsorbent has between 2 months and 2 weeks of life remaining, 
and at least daily if the adsorbent has 2 weeks or less of life 
remaining.
* * * * *
    (d) The owner or operator of an affected source with a controlled 
back-end process vent using a vent system that contains bypass lines 
that could divert a vent stream away from the control or recovery 
device used to comply with Sec.  63.494(a)(1) through (3), shall comply 
with either paragraph (d)(1) or (d)(2), and (d)(3) of this section. 
Except as specified in paragraph (d)(3) of this section, equipment such 
as low leg drains, high point bleeds, analyzer vents, open-ended valves 
or lines, and pressure relief valves needed for safety purposes are not 
subject to this paragraph.
* * * * *
    (3) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n):
    (i) The use of a bypass line at any time on a closed vent system to 
divert emissions (subject to the emission standards in Sec.  63.487) to 
the atmosphere or to a control device not meeting the requirements 
specified in this subpart is an emissions standards violation.
    (ii) The last sentence in paragraph (d) of this section no longer 
applies. Instead, the exemptions specified in paragraph (d)(3)(ii)(A) 
and (d)(3)(ii)(B) of this section apply.
    (A) Except for pressure relief devices subject to Sec.  
63.165(e)(4) of subpart H of this part, equipment such as low leg 
drains and equipment subject to the requirements of subpart H of this 
part are not subject to this paragraph (d) of this section.
    (B) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in 40 CFR 60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as 40 CFR 60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (d) of this section.

0
135. Amend Sec.  63.498 by:
0
a. Revising paragraph (a) introductory text;
0
b. Revising and republishing paragraph (d); and
0
c. Adding paragraph (f).
    The addition, revisions and republication read as follows:


Sec.  63.498  Back-end process provisions--recordkeeping.

    (a) Each owner or operator shall maintain the records specified in 
paragraphs (a)(1) through (4), and paragraphs (b) through (f) of this 
section, as appropriate.
* * * * *
    (d) Each owner or operator of a back-end process operation using 
control or recovery devices to comply with a residual organic HAP 
limitation in Sec.  63.494(a)(1) through (3), shall maintain the 
records specified in paragraphs (d)(1) through (5) of this section. The 
recordkeeping requirements contained in paragraphs (d)(1) through (4) 
pertain to the results of the testing required by Sec.  63.496(b), for 
each of the three required test runs.

[[Page 43253]]

    (1) The uncontrolled residual organic HAP content in the latex or 
dry crumb rubber, as required to be determined by Sec.  63.496(b)(3), 
including the test results of the analysis;
    (2) The total quantity of material (weight of latex or dry crumb 
rubber) processed during the test run, recorded in accordance with 
Sec.  63.496(b)(4);
    (3) The organic HAP emissions at the inlet and outlet of the 
control or recovery device, determined in accordance with Sec.  
63.496(b)(5) through (8), including all test results and calculations.
    (4) The residual organic HAP content, adjusted for the control or 
recovery device emission reduction, determined in accordance with Sec.  
63.496(c)(1).
    (5) Each owner or operator using a control or recovery device shall 
keep the following records readily accessible:
    (i) Continuous records of the equipment operating parameters 
specified to be monitored under Sec.  63.497(a) or specified by the 
Administrator in accordance with Sec.  63.497(b). For flares, the 
records specified in Sec.  63.508, if applicable, and table 3 to 
subpart G of this part shall be maintained in place of continuous 
records.
    (ii) Records of the daily average value of each continuously 
monitored parameter for each operating day, except as provided in 
paragraphs (d)(5)(ii)(D) through (d)(5)(ii)(F) of this section.
    (A) The daily average shall be calculated as the average of all 
values for a monitored parameter recorded during the operating day, 
except as provided in paragraph (d)(5)(ii)(B) of this section. The 
average shall cover a 24-hour period if operation is continuous, or the 
number of hours of operation per operating day if operation is not 
continuous.
    (B) Monitoring data recorded during periods of monitoring system 
breakdowns, repairs, calibration checks, and zero (low-level) and high-
level adjustments, shall not be included in computing the hourly or 
daily averages. In addition, monitoring data recorded during periods of 
non-operation of the EPPU (or specific portion thereof) resulting in 
cessation of organic HAP emissions, shall not be included in computing 
the hourly or daily averages. Records shall be kept of the times and 
durations of all such periods and any other periods of process or 
control device operation when monitors are not operating.
    (C) The operating day shall be the period defined in the operating 
permit or the Notification of Compliance Status in Sec.  63.506(e)(5) 
or (8). It may be from midnight to midnight or another 24-hour period.
    (D) If all recorded values for a monitored parameter during an 
operating day are below the maximum, or above the minimum, level 
established in the Notification of Compliance Status in Sec.  
63.506(e)(5) or in the operating permit, the owner or operator may 
record that all values were below the maximum or above the minimum 
level, rather than calculating and recording a daily average for that 
operating day.
    (E) Except as specified in paragraph (d)(5)(ii)(F) of this section, 
for flares, records of the times and duration of all periods during 
which the pilot flame is absent, shall be kept rather than daily 
averages. The records specified in this paragraph are not required 
during periods when emissions are not routed to the flare.
    (F) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (d)(5)(ii)(E) of this section no longer applies 
and instead the owner or operator of the affected source must keep the 
records specified in Sec.  63.108(m) of subpart F of this part and 
Sec.  63.508.
    (iii) Except as specified in paragraph (d)(5)(v) of this section, 
hourly records of whether the flow indicator specified under Sec.  
63.497(d)(1) was operating and whether a diversion was detected at any 
time during the hour, as well as records of the times of all periods 
when the vent stream is diverted from the control device or the flow 
indicator is not operating.
    (iv) Except as specified in paragraph (d)(5)(v) of this section, 
where a seal mechanism is used to comply with Sec.  63.497(d)(2), 
hourly records of flow are not required.
    (A) For compliance with Sec.  63.497(d)(2), the owner or operator 
shall record whether the monthly visual inspection of the seals or 
closure mechanisms has been done, and shall record instances when the 
seal mechanism is broken, the bypass line damper or valve position has 
changed, or the key for a lock-and-key type configuration has been 
checked out, and records of any car-seal that has broken.
    (B) [Reserved]
    (v) For each flow event from a bypass line subject to the 
requirements in Sec.  63.127(d) of subpart G of this part for each 
affected source as described in Sec.  63.480, beginning no later than 
the compliance dates specified in Sec.  63.481(n), the owner or 
operator must also maintain records sufficient to determine whether or 
not the detected flow included flow requiring control. For each flow 
event from a bypass line requiring control that is released either 
directly to the atmosphere or to a control device not meeting the 
requirements in this subpart, the owner or operator must include an 
estimate of the volume of gas, the concentration of organic HAP in the 
gas and the resulting emissions of organic HAP that bypassed the 
control device using process knowledge and engineering estimates.
* * * * *
    (f) Owners and operators subject to Sec.  63.494(a)(7), must keep 
the records specified in paragraphs (f)(1) and (2) of this section in 
addition to those records specified elsewhere in this section.
    (1) For back-end process vents in chloroprene service, include all 
uncontrolled, undiluted chloroprene concentration measurements, and the 
calculations used to determine the total uncontrolled chloroprene mass 
emission rate for the sum of all vent gas streams.
    (2) The owner or operator must keep records of all periods during 
which operating values are outside of the applicable operating limits 
specified in Sec.  63.510(b)(4) through (6) when regulated material is 
being routed to the non-flare control device. The record must specify 
the operating parameter, the applicable limit, and the highest (for 
maximum operating limits) or lowest (for minimum operating limits) 
value recorded during the period.

0
136. Amend Sec.  63.499 by adding paragraph (g) as follows:


Sec.  63.499  Back-end process provisions--reporting.

* * * * *
    (g) Owners and operators subject to Sec.  63.494(a)(7), must 
include in the periodic report, the records for the periods specified 
in Sec.  63.498(f)(2). Indicate the start date, start time and duration 
in hours for each period.

0
137. Amend Sec.  63.500 by revising paragraph (c)(1)(iii) introductory 
text to read as follows:


Sec.  63.500  Back-end process provisions--carbon disulfide limitations 
for styrene butadiene rubber by emulsion processes.

* * * * *
    (c) * * *
    (1) * * *
    (iii) To determine compliance with the carbon disulfide 
concentration limit in paragraph (a) of this section, the owner or 
operator shall use Method 18 or Method 25A of appendices A-6 and A-7 to 
40 CFR part 60, respectively to measure carbon disulfide. ASTM D6420-18 
(incorporated by reference, see Sec.  63.14) may also be used in lieu 
of Method 18, if the target compounds are all known and are all listed 
in Section

[[Page 43254]]

1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 must not be used for 
methane and ethane; and ASTM D6420-18 may not be used as a total VOC 
method. Alternatively, any other method or data that has been validated 
according to the applicable procedures in Method 301 of appendix A to 
this part, may be used. The following procedures shall be used to 
calculate carbon disulfide concentration:
* * * * *

0
138. Amend Sec.  63.501 by revising paragraphs (a) introductory text, 
revising and republishing (a)(10) and (20), and (b), and adding 
paragraphs (d), (e), and (f) to read as follows:


Sec.  63.501  Wastewater provisions.

    (a) Except as specified in paragraphs (c) through (f) of this 
section, the owner or operator of each affected source shall comply 
with the requirements of Sec. Sec.  63.132 through 63.147 for each 
process wastewater stream originating at an affected source, with the 
requirements of Sec.  63.148 for leak inspection provisions, and with 
the requirements of Sec.  63.149 for equipment that is subject to Sec.  
63.149, with the differences noted in paragraphs (a)(1) through (23) of 
this section. Further, the owner or operator of each affected source 
shall comply with the requirements of Sec.  63.105(a) for maintenance 
wastewater, as specified in paragraph (b) of this section.
* * * * *
    (10) The provisions of paragraphs (a)(10)(i) through (iv) of this 
section clarify the organic HAP that an owner or operator must consider 
when complying with the requirements of Sec. Sec.  63.132 through 
63.149.
    (i) Owners and operators are exempt from all requirements in 
Sec. Sec.  63.132 through 63.149 that pertain solely and exclusively to 
organic HAP listed on table 8 to 40 CFR part 63, subpart G.
    (ii) When Sec. Sec.  63.132 through 63.149 refer to table 9 
compounds, the owner or operator is only required to consider compounds 
that meet the definition of organic HAP in Sec.  63.482 and that are 
listed in table 9 to 40 CFR part 63, subpart G, for the purposes of 
this subpart.
    (iii) When Sec. Sec.  63.132 through 63.149 refer to compounds in 
table 36 to 40 CFR part 63, subpart G, or compounds in List 1 and/or 
List 2, as listed in table 36 to 40 CFR part 63, subpart G, the owner 
or operator is only required to consider compounds that meet the 
definition of organic HAP in Sec.  63.482 and that are listed in table 
36 to 40 CFR part 63, subpart G, for the purposes of this subpart.
    (iv) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(o), the provisions specified in Sec.  63.132(c)(1)(iii) do not 
apply. Instead, if the wastewater stream contains chloroprene such that 
it is considered to be in chloroprene service, as defined in Sec.  
63.482, then the wastewater stream is a Group 1 wastewater stream. For 
wastewater streams in chloroprene service, owners and operators must 
also meet the requirements specified in Sec.  63.510.
* * * * *
    (20) When the provisions of Sec.  63.139(c)(1)(ii), Sec.  
63.145(d)(4), or Sec.  63.145(i)(2) specify that Method 18 of appendix 
A-6 to 40 CFR part 60 must be used, Method 18 or Method 25A of 
appendices A-6 and A-7 to 40 CFR part 60, respectively, may be used for 
the purposes of this subpart. ASTM D6420-18 (incorporated by reference, 
see Sec.  63.14) may also be used in lieu of Method 18, if the target 
compounds are all known and are all listed in Section 1.1 of ASTM 
D6420-18 as measurable; ASTM D6420-18 must not be used for methane and 
ethane; and ASTM D6420-18 may not be used as a total VOC method. The 
use of Method 25A must conform with the requirements in paragraphs 
(a)(20)(i) and (ii) of this section.
    (i) The organic HAP used as the calibration gas for Method 25A of 
appendix A-7 to 40 CFR part 60 must be the single organic HAP 
representing the largest percent by volume of the emissions.
    (ii) The use of Method 25A of appendix A-7 to 40 CFR part 60 is 
acceptable if the response from the high-level calibration gas is at 
least 20 times the standard deviation of the response from the zero 
calibration gas when the instrument is zeroed on the most sensitive 
scale
    (b) Except for those streams exempted by paragraphs (c) and (d) of 
this section, the owner or operator of each affected source shall 
comply with the requirements for maintenance wastewater in Sec.  
63.105, except that when Sec.  63.105(a) refers to ``organic HAPs 
listed in table 9 to subpart G of this part,'' the owner or operator is 
only required to consider compounds that meet the definition of organic 
HAP in Sec.  63.482 and that are listed in table 9 to subpart G of this 
part, for the purposes of this subpart.
* * * * *
    (d) Substitute ``For each affected source as described in Sec.  
63.480, on and after July 15, 2027,'' for each occurrence of ``For each 
source as defined in Sec.  63.101, on and after July 15, 2027,''.
    (e) Substitute ``For each affected source as described in Sec.  
63.480, beginning no later than the compliance dates specified in Sec.  
63.481(n),'' for each occurrence of ``For each source as defined in 
Sec.  63.101, beginning no later than the compliance dates specified in 
Sec.  63.100(k)(10),''.
    (f) Substitute ``Sec.  63.508'' for each occurrence of ``Sec.  
63.108''.

0
139. Amend Sec.  63.502 by revising the section heading, paragraphs (a) 
(j), (k), and (n) to read as follows:


Sec.  63.502  Equipment leak, fenceline monitoring, and heat exchange 
system provisions.

    (a) The owner or operator of each affected source, shall comply 
with the requirements of subpart H of this part, with the exceptions 
noted in paragraphs (a)(1) through (7), and (b) through (m) of this 
section. Except as specified in Sec.  63.170(b), surge control vessels 
required to be controlled by subpart H may, alternatively, comply with 
the Group 1 storage vessel provisions specified in Sec.  63.484.
    (1) Substitute ``For each affected source as described in Sec.  
63.480, on and after July 15, 2027,'' for each occurrence of ``For each 
source as defined in Sec.  63.101, and for each source as defined in 
Sec.  63.191, on and after July 15, 2027,''.
    (2) Substitute ``For each affected source as described in Sec.  
63.480, beginning no later than the compliance dates specified in Sec.  
63.481(n),'' for each occurrence of ``For each source as defined in 
Sec.  63.101, and for each source as defined in Sec.  63.191, beginning 
no later than the compliance dates specified in Sec.  63.100(k)(10),''.
    (3) Substitute ``For each affected source as described in Sec.  
63.480, beginning no later than the compliance dates specified in Sec.  
63.481(o),'' for each occurrence of ``For each source as defined in 
Sec.  63.101, and for each source as defined in Sec.  63.191, beginning 
no later than the compliance dates specified in Sec.  63.100(k)(11),''.
    (4) Substitute ``For each affected source as described in Sec.  
63.480, beginning no later than the compliance dates specified in Sec.  
63.481(p),'' for each occurrence of ``For each source as defined in 
Sec.  63.101, and for each source as defined in Sec.  63.191, beginning 
no later than the compliance dates specified in Sec.  63.100(k)(12),''.
    (5) Substitute ``Sec.  63.508'' for each occurrence of ``Sec.  
63.108''.
    (6) Substitute ``in chloroprene service'' for each occurrence of 
``in ethylene oxide service''.

[[Page 43255]]

    (7) If an affected source uses, produces, stores, or emits 
chloroprene, the action level for chloroprene in Sec.  63.184(d)(3) is 
0.3 [micro]g/m\3\ on an annual average basis for the purposes of this 
subpart. Additionally, the sampling period [Delta]c in Sec.  
63.184(e)(4)(iii) and (f)(1)(iii) is 0.3 [micro]g/m\3\ instead of 0.8 
[micro]g/m\3\ for the purposes of this subpart.
* * * * *
    (j) When the provisions of subpart H of this part specify that 
Method 18 of appendix A-6 to 40 CFR part 60 must be used, either Method 
18 or Method 25A of appendices A-6 and A-7 to 40 CFR part 60, 
respectively, may be used for the purposes of this subpart. ASTM D6420-
18 (incorporated by reference, see Sec.  63.14) may also be used in 
lieu of Method 18, if the target compounds are all known and are all 
listed in Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 
must not be used for methane and ethane; and ASTM D6420-18 may not be 
used as a total VOC method. The use of Method 25A must conform with the 
requirements in paragraphs (j)(1) and (2) of this section.
    (1) The organic HAP used as the calibration gas for Method 25A of 
appendix A-7 to 40 CFR part 60 must be the single organic HAP 
representing the largest percent by volume of emissions.
    (2) The use of Method 25A of appendix A-7 to 40 CFR part 60 is 
acceptable if the response from the high-level calibration gas is at 
least 20 times the standard deviation of the response from the zero 
calibration gas when the instrument is zeroed on the most sensitive 
scale.
    (k)(1) Except as specified in paragraph (k)(2) of this section, an 
owner or operator using a flare to comply with the requirements of this 
section shall conduct a compliance demonstration as specified in Sec.  
63.504(c).
    (2) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), paragraph (k)(1) of this section no longer applies and 
instead the owner or operator of the affected source must comply with 
Sec.  63.508 for the flare.
* * * * *
    (n) The owner or operator of each affected source shall comply with 
the requirements of Sec.  63.104 for heat exchange systems, with the 
exceptions noted in paragraphs (n)(1) through (8) of this section.
    (1) When the term ``chemical manufacturing process unit'' is used 
in Sec.  63.104, the term ``elastomer product process unit'' (or EPPU) 
shall apply for the purposes of this subpart, with the exception noted 
in paragraph (n)(2) of this section.
    (2) When the phrase ``a chemical manufacturing process unit meeting 
the conditions of Sec.  63.100(b)(1) through (b)(3) of this subpart, 
except for chemical manufacturing process units meeting the condition 
specified in Sec.  63.100(c) of this subpart'' is used in the first 
sentence of Sec.  63.104(a), the term ``an EPPU, except for EPPUs 
meeting the condition specified in Sec.  63.480(b)'' shall apply for 
the purposes of this subpart. When the phrase ``a chemical 
manufacturing process unit meeting the conditions of Sec.  63.100(b)(1) 
through (b)(3),'' is used in the last sentence of Sec.  63.104(a) of 
subpart F of this part, the term ``an EPPU'' shall apply for purposes 
of this subpart.
    (3) When Sec.  63.104 refers to table 4 to subpart F of this part 
or table 9 to subpart G of this part, the owner or operator is only 
required to consider organic HAP listed on table 5 to this subpart.
    (4) When Sec.  63.104(c)(3) specifies the monitoring plan retention 
requirements, and when Sec.  63.104(f)(1) refers to the record 
retention requirements in Sec.  63.103(c)(1), the requirements in Sec.  
63.506(a) and Sec.  63.506(h) shall apply, for the purposes of this 
subpart.
    (5) When Sec.  63.104(f)(2) requires information to be reported in 
the Periodic Reports required by Sec.  63.152(c), the owner or operator 
shall instead report the information specified in Sec.  63.104(f)(2) in 
the Periodic Reports required by Sec.  63.506(e)(6), for the purposes 
of this subpart.
    (6) The compliance date for heat exchange systems subject to the 
provisions of this section is specified in Sec.  63.481(d)(6).
    (7) Substitute ``Beginning no later than the compliance dates 
specified in Sec.  63.481(n),'' for each occurrence of ``Beginning no 
later than the compliance dates specified in Sec.  63.100(k)(10),''.
    (8) Sec.  63.104(k) of subpart F of this part does not apply. 
Instead for each source as described in Sec.  63.480, beginning no 
later than the compliance dates specified in Sec.  63.481(n), owners 
and operators must not inject water into or dispose of water through 
any heat exchange system in an EPPU if the water contains any amount of 
chloroprene, has been in contact with any process stream containing 
chloroprene, or the water is considered wastewater as defined in Sec.  
63.482.

0
140. Amend Sec.  63.503 by revising paragraphs (a)(3), (g)(2)(ii) 
introductory text and (g)(2)(iii)(B)(2), adding paragraph 
(g)(2)(iii)(B)(4), and revising paragraphs (g)(7)(ii) introductory 
text, (m)(1)(ii) and (m)(2)(i) to read as follows:


Sec.  63.503  Emissions averaging provisions.

    (a) * * *
    (3) For the purposes of the provisions in this section, whenever 
Method 18 of appendix A-6 to 40 CFR part 60 is specified within the 
paragraphs of this section or is specified by reference through 
provisions outside this section, Method 18 or Method 25A of appendices 
A-6 and A-7 to 40 CFR part 60, respectively, may be used. ASTM D6420-18 
(incorporated by reference, see Sec.  63.14) may also be used in lieu 
of Method 18, if the target compounds are all known and are all listed 
in Section 1.1 of ASTM D6420-18 as measurable; ASTM D6420-18 must not 
be used for methane and ethane; and ASTM D6420-18 may not be used as a 
total VOC method. The use of Method 25A, must conform with the 
requirements in paragraphs (a)(3)(i) and (ii) of this section.
    (i) The organic HAP used as the calibration gas for Method 25Aof 
appendix A-7 to 40 CFR part 60 must be the single organic HAP 
representing the largest percent by volume of the emissions.
    (ii) The use of Method 25A of appendix A-7 to 40 CFR part 60, is 
acceptable if the response from the high-level calibration gas is at 
least 20 times the standard deviation of the response from the zero 
calibration gas when the instrument is zeroed on the most sensitive 
scale.
* * * * *
    (g) * * *
    (2) * * *
    (ii) ECFEPViu for each continuous front-end process vent 
i shall be calculated using equation 34.
[GRAPHIC] [TIFF OMITTED] TR16MY24.065


[[Page 43256]]


Where:

ECFEPViu = Uncontrolled continuous front-end process vent 
emission rate from continuous front-end process vent i, Mg/month.
Q = Vent stream flow rate, dry standard m\3\/min, measured using 
Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A, as 
appropriate.
h = Monthly hours of operation during which positive flow is present 
in the continuous front-end process vent, hr/month.
Cj = Concentration, ppmv, dry basis, of organic HAP j as 
measured by Method 18 or Method 25A of appendices A-6 and A-7 to 40 
CFR part 60, respectively, or ASTM D6420-18 (incorporated by 
reference, see Sec.  63.14).
Mj = Molecular weight of organic HAP j, gram per gram-
mole.
n = Number of organic HAP in stream.
* * * * *
    (iii) * * *
    (B) * * *
    (2) For determining debits from Group 1 continuous front-end 
process vents, product recovery devices shall not be considered control 
devices and shall not be assigned a percent reduction in calculating 
ECFEPViACTUAL. The sampling site for measurement of 
uncontrolled emissions shall be after the final uncontrolled recovery 
device. However, as provided in Sec.  63.113(a)(3), a Group 1 
continuous front-end process vent may add sufficient product recovery 
to raise the TRE index value above 1.0, thereby becoming a Group 2 
continuous front-end process vent. Such a continuous front-end process 
vent is not a Group 1 continuous front-end process vent and should, 
therefore, not be included in determining debits under this paragraph, 
except as specified in paragraph (g)(2)(iii)(B)(4) of this section.
* * * * *
    (4) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), that last two sentences of paragraph (g)(2)(iii)(B)(2) of 
this section no longer apply.
* * * * *
    (7) * * *
    (ii) EABViu for each aggregate batch vent i shall be 
calculated using equation 39.
[GRAPHIC] [TIFF OMITTED] TR16MY24.066

Where:

EABViu = Uncontrolled aggregate batch vent emission rate 
from aggregate batch vent i, Mg/month.
Q = Vent stream flow rate, dry standard cubic meters per minute, 
measured using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix 
A, as appropriate.
h = Monthly hours of operation during which positive flow is present 
from the aggregate batch vent stream, hr/month.
Cj = Concentration, ppmv, dry basis, of organic HAP j as 
measured by Method 18 of appendix A-6 to 40 CFR part 60 or ASTM 
D6420-18 (incorporated by reference, see Sec.  63.14).
Mj = Molecular weight of organic HAP j, gram per gram-
mole.
n = Number of organic HAP in the stream.
* * * * *
    (m) * * *
    (1) * * *
    (ii) Conduct initial and subsequent performance tests to determine 
percent reduction as specified in Sec.  63.116 and as required by Sec.  
63.485; and
* * * * *
    (2) * * *
    (i) Determine the flow rate, organic HAP concentration, and TRE 
index value according to the procedures specified in Sec.  63.115, 
except as specified in Sec.  63.113(a)(4) and Sec.  63.485(x); and
* * * * *

0
141. Amend Sec.  63.504 by revising paragraphs (a) introductory text 
and (a)(1) introductory text, adding paragraph (a)(1)(iii), revising 
paragraph (c) introductory text and adding paragraph (c)(4) to read as 
follows:


Sec.  63.504  Additional requirements for performance testing.

    (a) Performance testing shall be conducted in accordance with Sec.  
63.7(a)(1), (a)(3), (d), (e)(1) and (2), (e)(4), (g), and (h), with the 
exceptions specified in paragraphs (a)(1) through (5) of this section 
and the additions specified in paragraph (b) of this section. Sections 
63.484 through 63.501 also contain specific testing requirements. 
Beginning no later than the compliance dates specified in Sec.  
63.481(n), conduct subsequent performance tests no later than 60 
calendar months after the previous performance test.
    (1) Except as specified in paragraph (a)(1)(iii) of this section, 
performance tests shall be conducted at maximum representative 
operating conditions achievable during one of the time periods 
described in paragraph (a)(1)(i) of this section, without causing any 
of the situations described in paragraph (a)(1)(ii) of this section to 
occur. Upon request, the owner or operator shall make available to the 
Administrator such records as may be necessary to determine the 
conditions of performance tests.
* * * * *
    (iii) Beginning no later than the compliance dates specified in 
Sec.  63.481(n), paragraphs (a)(1)(i) and (ii) of this section no 
longer applies and instead the owner or operator must conduct 
performance tests under such conditions as the Administrator specifies 
based on representative performance of the affected source for the 
period being tested. Representative conditions exclude periods of 
startup and shutdown. You may not conduct performance tests during 
periods of malfunction. You must record the process information that is 
necessary to document operating conditions during the test and include 
in such record an explanation to support that such conditions represent 
normal operation. Upon request, you must make available to the 
Administrator such records as may be necessary to determine the 
conditions of performance tests.
* * * * *
    (c) Except as specified in paragraph (c)(4) of this section, 
notwithstanding any other provision of this subpart, if an owner or 
operator of an affected source uses a flare to comply with any of the 
requirements of this subpart, the owner or operator shall comply with 
paragraphs (c)(1) through (3) of this section. The owner or operator is 
not required to conduct a performance test to determine percent 
emission reduction or outlet organic HAP or TOC concentration. If a 
compliance demonstration has been conducted previously for a flare, 
using the techniques specified in paragraphs (c)(1) through (3) of this 
section, that compliance demonstration may be used to satisfy the 
requirements of this paragraph if either no deliberate process changes 
have been made since the compliance demonstration, or the results of 
the compliance demonstration reliably demonstrate compliance despite 
process changes.
* * * * *
    (4) For each affected source as described in Sec.  63.480, 
beginning no later

[[Page 43257]]

than the compliance dates specified in Sec.  63.481(n), paragraphs 
(c)(1) through (c)(3) of this section no longer apply and instead the 
owner or operator of the affected source must comply with Sec.  63.508 
for the flare.

0
142. Amend Sec.  63.505 by:
0
a. Revising and republishing paragraph (b); and
0
b. Revising paragraph (g)(2)(ii)(B) introductory text and adding 
paragraph (g)(2)(ii)(B)(5).
    The addition, revisions, and republication read as follows:


Sec.  63.505  Parameter monitoring levels and excursions.

* * * * *
    (b) Establishment of parameter monitoring levels based exclusively 
on performance tests. In cases where a performance test is required by 
this subpart, or the owner or operator of the affected source elects to 
do a performance test in accordance with the provisions of this 
subpart, and an owner or operator elects to establish a parameter 
monitoring level for a control, recovery, or recapture device based 
exclusively on parameter values measured during the performance test, 
the owner or operator of the affected source shall comply with the 
procedures in paragraphs (b)(1) through (b)(5) of this section, as 
applicable.
    (1) [Reserved]
    (2) Back-end process operations using a control or recovery device 
to comply with Sec. Sec.  63.493 through 63.500 and continuous front-
end process vents. During each compliance test, the appropriate 
parameter shall be continuously monitored during the required 1-hour 
runs. The monitoring level(s) shall then be established as the average 
of the maximum (or minimum) point values from the three test runs. The 
average of the maximum values shall be used when establishing a maximum 
level, and the average of the minimum values shall be used when 
establishing a minimum level.
    (3) Batch front-end process vents. The monitoring level(s) shall be 
established using the procedures specified in either paragraph 
(b)(3)(i) or (b)(3)(ii) of this section, except as specified in 
paragraph (b)(5) of this section. The procedures specified in this 
paragraph (b)(3) may only be used if the batch emission episodes, or 
portions thereof, selected to be controlled were tested, and monitoring 
data were collected, during the entire period in which emissions were 
vented to the control device, as specified in Sec.  63.490(c)(1)(i). If 
the owner or operator chose to test only a portion of the batch 
emission episode, or portion thereof, selected to be controlled, the 
procedures in paragraph (c) of this section shall be used.
    (i) If more than one batch emission episode or more than one 
portion of a batch emission episode has been selected to be controlled, 
a single level for the batch cycle shall be calculated as follows:
    (A) The average monitored parameter value shall be calculated for 
each batch emission episode, or portion thereof, in the batch cycle 
selected to be controlled. The average shall be based on all values 
measured during the required performance test.
    (B) If the level to be established is a maximum operating 
parameter, the level shall be defined as the minimum of the average 
parameter values of the batch emission episodes, or portions thereof, 
in the batch cycle selected to be controlled (i.e., identify the 
emission episode, or portion thereof, which requires the lowest 
parameter value in order to assure compliance. The average parameter 
value that is necessary to assure compliance for that emission episode, 
or portion thereof, shall be the level for all emission episodes, or 
portions thereof, in the batch cycle, that are selected to be 
controlled).
    (C) If the level to be established is a minimum operating 
parameter, the level shall be defined as the maximum of the average 
parameter values of the batch emission episodes, or portions thereof, 
in the batch cycle selected to be controlled (i.e., identify the 
emission episode, or portion thereof, which requires the highest 
parameter value in order to assure compliance. The average parameter 
value that is necessary to assure compliance for that emission episode, 
or portion thereof, shall be the level for all emission episodes, or 
portions thereof, in the batch cycle, that are selected to be 
controlled).
    (D) Alternatively, an average monitored parameter value shall be 
calculated for the entire batch cycle based on all values measured 
during each batch emission episode, or portion thereof, selected to be 
controlled.
    (ii) Instead of establishing a single level for the batch cycle, as 
described in paragraph (b)(3)(i) of this section, an owner or operator 
may establish separate levels for each batch emission episode, or 
portion thereof, selected to be controlled. Each level shall be 
determined as specified in paragraph (b)(3)(i)(A) of this section.
    (iii) The batch cycle shall be defined in the Notification of 
Compliance Status, as specified in Sec.  63.506(e)(5). The definition 
shall include an identification of each batch emission episode and the 
information required to determine parameter monitoring compliance for 
partial batch cycles (i.e., when part of a batch cycle is accomplished 
during two different operating days).
    (4) Aggregate batch vent streams. For aggregate batch vent streams, 
except as specified in paragraph (b)(5) of this section, the monitoring 
level shall be established in accordance with paragraph (b)(2) of this 
section.
    (5) Batch front-end process vents and aggregate batch vent streams 
testing for dioxins and furans. During each compliance test using the 
procedures specified in Sec.  63.490(g), the appropriate parameter 
shall be continuously monitored during the required test runs. The 
monitoring level(s) shall then be established as the average of the 
maximum (or minimum) point values from the three test runs. The average 
of the maximum values shall be used when establishing a maximum level, 
and the average of the minimum values shall be used when establishing a 
minimum level.
* * * * *
    (g) * * *
    (2) * * *
    (ii) * * *
    (B) Except as specified in paragraph (g)(2)(ii)(B)(5) of this 
section, subtract the time during the periods identified in paragraphs 
(g)(2)(ii)(B)(1) through (4) of this section from the total amount of 
time determined in paragraph (g)(2)(ii)(A) of this section, to obtain 
the operating time used to determine if monitoring data are 
insufficient.
* * * * *
    (5) On and after July 15, 2027, paragraphs (g)(2)(ii)(B)(1) through 
(4) of this section no longer apply.
* * * * *

0
143. Amend Sec.  63.506 by:
0
a. Revising and republishing paragraph (b)(1);
0
b. Revising paragraph (e)(4)(ii)(F)(1);
0
c. Adding paragraph (e)(4)(ii)(F)(6);
0
d. Revising paragraph (e)(5) introductory text;
0
e. Revising and republishing paragraph (e)(5)(i);
0
f. Adding paragraph (e)(5)(xiii);
0
g. Revising and republishing paragraph (e)(6);
0
h. Revising paragraph (e)(7) introductory text;
0
i. Adding paragraph (e)(7)(vi);
0
j. Revising paragraph (i)(1); and
0
k. Adding paragraph (i)(3).
    The additions, revisions, and republications read as follows:


Sec.  63.506  General recordkeeping and reporting provisions.

* * * * *
    (b) * * *

[[Page 43258]]

    (1) Malfunction records. Each owner or operator of an affected 
source subject to this subpart shall maintain records of the occurrence 
and duration of each malfunction of operation (i.e., process 
equipment), air pollution control equipment, or monitoring equipment. 
Each owner or operator shall maintain records of actions taken during 
periods of malfunction to minimize emissions in accordance with Sec.  
63.483(a), including corrective actions to restore malfunctioning 
process and air pollution control and monitoring equipment to its 
normal or usual manner of operation.
    (i) Records of start-up, shutdown, and malfunction. Except as 
specified in paragraph (b)(1)(i)(D) of this section, the owner or 
operator shall keep the records specified in paragraphs (b)(1)(i)(A) 
through (b)(1)(i)(C) of this section.
    (A) Records of the occurrence and duration of each start-up, 
shutdown, and malfunction of operation of process equipment or control 
devices or recovery devices or continuous monitoring systems used to 
comply with this subpart during which excess emissions occur.
    (B) For each start-up, shutdown, or malfunction during which excess 
emissions occur, records reflecting whether the procedures specified in 
the affected source's start-up, shutdown, and malfunction plan were 
followed, and documentation of actions taken that are not consistent 
with the plan. For example, if a start-up, shutdown, and malfunction 
plan includes procedures for routing a control device to a backup 
control device, records shall be kept of whether the plan was followed. 
These records may take the form of a ``checklist,'' or other form of 
recordkeeping that confirms conformance with the start-up, shutdown, 
and malfunction plan for the event.
    (C) Records specified in paragraphs (b)(1)(i)(A) and (B) of this 
section are not required if they pertain solely to Group 2 emission 
points that are not included in an emissions average.
    (D) On and after July 15, 2027, paragraphs (b)(1)(i)(A) through 
(b)(1)(i)(C) no longer apply; however, for historical compliance 
purposes, a copy of these records must be retained and available on-
site for five years after July 15, 2027.
    (ii) Reports of start-up, shutdown, and malfunction. For the 
purposes of this subpart, the semiannual start-up, shutdown, and 
malfunction reports shall be submitted on the same schedule as the 
Periodic Reports required under paragraph (e)(6) of this section 
instead of the schedule specified in Sec.  63.10(d)(5)(i). The reports 
shall include the information specified in Sec.  63.10(d)(5)(i). On and 
after July 15, 2027, this paragraph no longer applies.
* * * * *
    (e) * * *
    (4) * * *
    (ii) * * *
    (F) * * *
    (1) The required documentation shall include the values of the 
parameters used to determine whether the emission point is Group 1 or 
Group 2. Except as specified in paragraph (e)(4)(ii)(F)(6) of this 
section, where a TRE index value is used for continuous front-end 
process vent group determination, the estimated or measured values of 
the parameters used in the TRE equation in Sec.  63.115(d) and the 
resulting TRE index value shall be submitted.
* * * * *
    (6) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), that last sentence of paragraph (e)(4)(ii)(F)(1) of this 
section no longer applies.
* * * * *
    (5) Notification of Compliance Status. For existing and new 
affected sources, a Notification of Compliance Status shall be 
submitted. For equipment leaks subject to Sec.  63.502, the owner or 
operator shall submit the information required in Sec.  63.182(c) in 
the Notification of Compliance Status within 150 days after the first 
applicable compliance date for equipment leaks in the affected source, 
and an update shall be provided in the first Periodic Report that is 
due at least 150 days after each subsequent applicable compliance date 
for equipment leaks in the affected source. For all other emission 
points, including heat exchange systems, the Notification of Compliance 
Status shall contain the information listed in paragraphs (e)(5)(i) 
through (xiii) of this section, as applicable, and shall be submitted 
no later than 150 days after the compliance dates specified in this 
subpart.
    (i) The results of any emission point group determinations, process 
section applicability determinations, performance tests, inspections, 
any other information used to demonstrate compliance, values of 
monitored parameters established during performance tests, and any 
other information required to be included in the Notification of 
Compliance Status under Sec. Sec.  63.122 and 63.484 for storage 
vessels, Sec.  63.117 for continuous front-end process vents, Sec.  
63.492 for batch front-end process vents, Sec.  63.499 for back-end 
process operations, Sec.  63.146 for process wastewater, and Sec.  
63.503 for emission points included in an emissions average. In 
addition, the owner or operator of an affected source shall comply with 
paragraphs (e)(5)(i)(A) and (B) of this section.
    (A) For performance tests, group determinations, and process 
section applicability determinations that are based on measurements, 
the Notification of Compliance Status shall include one complete test 
report, except as specified in paragraph (e)(5)(i)(B) of this section, 
for each test method used for a particular kind of emission point. For 
additional tests performed for the same kind of emission point using 
the same method, the results and any other information, from the test 
report, that is requested on a case-by-case basis by the Administrator 
shall be submitted, but a complete test report is not required.
    (B) If the performance test results have been submitted 
electronically via the Compliance and Emissions Data Reporting 
Interface (CEDRI) in accordance with paragraph (i) of this section, the 
unit(s) tested, the pollutant(s) tested, and the date that such 
performance test was conducted may be submitted in the Notification of 
Compliance Status in lieu of the performance test report. The 
performance test results must be submitted to CEDRI by the date the 
Notification of Compliance Status is submitted. A complete test report 
shall include a brief process description, sampling site description, 
description of sampling and analysis procedures and any modifications 
to standard procedures, quality assurance procedures, record of 
operating conditions during the test, record of preparation of 
standards, record of calibrations, raw data sheets for field sampling, 
raw data sheets for field and laboratory analyses, documentation of 
calculations, and any other information required by the test method.
* * * * *
    (xiii) For flares subject to the requirements in Sec.  63.508, 
owners and operators must also submit the information in this paragraph 
in a supplement to the Notification of Compliance Status within 150 
days after the first applicable compliance date for flare monitoring. 
The supplement to the Notification of Compliance Status must include 
flare design (e.g., steam-assisted, air-assisted, or non-assisted); all 
visible emission readings, heat content determinations, flow rate 
measurements, and exit velocity determinations made during the initial 
visible emissions demonstration required by Sec.  63.670(h), as 
applicable;

[[Page 43259]]

and all periods during the compliance determination when the pilot 
flame or flare flame is absent.
    (6) Periodic Reports. For existing and new affected sources, the 
owner or operator shall submit Periodic Reports as specified in 
paragraphs (e)(6)(i) through (xiii) of this section. In addition, for 
equipment leaks subject to Sec.  63.502, the owner or operator shall 
submit the information specified in Sec.  63.182(d) under the 
conditions listed in Sec.  63.182(d) as part of the Periodic Report 
required by this paragraph (e)(6), and for heat exchange systems 
subject to Sec.  63.502(n), the owner or operator shall submit the 
information specified in Sec.  63.104(f)(2) as part of the Periodic 
Report required by this paragraph (e)(6). Section Sec.  63.505 shall 
govern the use of monitoring data to determine compliance for Group 1 
emission points and for Group 1 and Group 2 emission points included in 
emissions averages with the following exception: As discussed in Sec.  
63.484(k), for storage vessels to which the provisions of Sec.  63.505 
do not apply, as specified in the monitoring plan required by Sec.  
63.120(d)(2), the owner or operator is required to comply with the 
requirements set out in the monitoring plan, and monitoring records may 
be used to determine compliance. On and after July 15, 2027 or once the 
reporting template for this subpart has been available on the CEDRI 
website for 1 year, whichever date is later, owners and operators must 
submit all subsequent reports following the procedure specified in 
Sec.  63.9(k), except any medium submitted through mail must be sent to 
the attention of the Polymers and Resins Sector Lead. Owners and 
operators must use the appropriate electronic report template on the 
CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for this subpart. The date report templates become available 
will be listed on the CEDRI website. Unless the Administrator or 
delegated state agency or other authority has approved a different 
schedule for submission of reports under Sec.  63.9(i) and Sec.  
63.10(a), the report must be submitted by the deadline specified in 
this subpart, regardless of the method in which the report is 
submitted.
    (i) Except as specified in paragraphs (e)(6)(xi) and (xii) of this 
section, a report containing the information in paragraph (e)(6)(ii) of 
this section or paragraphs (e)(6)(iii) through (x) and (xiii) of this 
section, as appropriate, shall be submitted semiannually no later than 
60 days after the end of each 6-month period. The first report shall be 
submitted no later than 240 days after the date the Notification of 
Compliance Status is due and shall cover the 6-month period beginning 
on the date the Notification of Compliance Status is due. All periodic 
reports must contain the company name and address (including county), 
as well as the beginning and ending dates of the reporting period.
    (ii) If none of the compliance exceptions in paragraphs (e)(6)(iii) 
through (ix) or (xiii) of this section occurred during the 6-month 
period, the Periodic Report required by paragraph (e)(6)(i) of this 
section shall be a statement that there were no compliance exceptions 
as described in this paragraph for the 6-month period covered by that 
report and that none of the activities specified in paragraphs 
(e)(6)(iii) through (ix) or (xiii) of this section occurred during the 
6-month period covered by that report.

    For an owner or operator of an affected source complying with the 
provisions of Sec. Sec.  63.484 through 63.501 for any emission point, 
Periodic Reports shall include:
    (A) All information specified in Sec.  63.122(a)(4) for storage 
vessels, Sec. Sec.  63.117(a)(3) and 63.118(f) and 63.485(s)(5) for 
continuous front-end process vents, Sec.  63.492 for batch front-end 
process vents and aggregate batch vent streams, Sec.  63.499 for back-
end process operations, Sec.  63.104(f)(2) for heat exchange systems, 
and Sec. Sec.  63.146(c) through 63.146(g) for process wastewater.
    (B) The daily average values or batch cycle daily average values of 
monitored parameters for all excursions, as defined in Sec.  63.505(g) 
and Sec.  63.505(h). For excursions caused by lack of monitoring data, 
the start date and time and duration (in hours) of periods when 
monitoring data were not collected shall be specified.
    (C) For each affected source as described in Sec.  63.480, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), for each excursion that is not an excused excursion, the 
report must include the date of the excursion, a list of the affected 
sources or equipment, an estimate of the quantity in pounds of each 
regulated pollutant emitted over any emission limit, a description of 
the method used to estimate the emissions, the cause of the excursion 
(including unknown cause, if applicable), as applicable, and the 
corrective action taken.
    (D) The information in paragraphs (e)(6)(iii)(D)(1) through 
(e)(6)(iii)(D)(5) of this section, as applicable:
    (1) Any supplements to the Emissions Averaging Plan, as required in 
paragraph (e)(4)(iii) of this section;
    (2) Notification if a process change is made such that the group 
status of any emission point changes from Group 2 to Group 1. The owner 
or operator is not required to submit a notification of a process 
change if that process change caused the group status of an emission 
point to change from Group 1 to Group 2. However, until the owner or 
operator notifies the Administrator that the group status of an 
emission point has changed from Group 1 to Group 2, the owner or 
operator is required to continue to comply with the Group 1 
requirements for that emission point. This notification may be 
submitted at any time.
    (3) Notification if one or more emission points (other than 
equipment leaks) or one or more EPPU is added to an affected source. 
The owner or operator shall submit the information contained in 
paragraphs (e)(6)(iii)(D)(3)(i) through (e)(6)(iii)(D)(3)(ii) of this 
section.
    (i) A description of the addition to the affected source; and
    (ii) Notification of the group status of the additional emission 
point or all emission points in the EPPU.
    (4) Notification if a standard operating procedure, as defined in 
Sec.  63.500(a)(2), is changed and the change has the potential for 
increasing the concentration of carbon disulfide in the crumb dryer 
exhaust. This notification shall also include a summary of the test 
results of the carbon disulfide concentration resulting from the new 
standard operating procedure. The results of the performance test must 
be submitted according to paragraph (i) of this section by the date the 
Periodic Report is submitted.
    (5) For process wastewater streams sent for treatment pursuant to 
Sec.  63.132(g), reports of changes in the identity of the treatment 
facility or transferee.
    (E) The start date, start time, duration in hours, and a brief 
description for each type of malfunction which occurred during the 
reporting period and which caused or may have caused any applicable 
emission limitation to be exceeded. The report must also include a 
description of actions taken by an owner or operator during a 
malfunction of an affected source to minimize emissions in accordance 
with Sec.  63.483(a), including actions taken to correct a malfunction.
    (iv) For each batch front-end process vent with a batch mass input 
limitation, every second Periodic Report shall include the mass of HAP 
or material input to the batch unit operation during the 12-month 
period covered by the preceding and current Periodic Reports, and a 
statement of whether the batch

[[Page 43260]]

front-end process vent was in or out of compliance with the batch mass 
input limitation.
    (v) Except as specified in paragraph (i) of this section, if any 
performance tests are reported in a Periodic Report, the following 
information shall be included:
    (A) One complete test report shall be submitted for each test 
method used for a particular kind of emission point tested. A complete 
test report shall contain the information specified in paragraph 
(e)(5)(i)(B) of this section.
    (B) For additional tests performed for the same kind of emission 
point using the same method, results and any other information, 
pertaining to the performance test, that is requested on a case-by-case 
basis by the Administrator shall be submitted, but a complete test 
report is not required.
    (vi) Notification of a change in the primary product of an EPPU, in 
accordance with the provisions in Sec.  63.480(f). This includes a 
change in primary product from one elastomer product to either another 
elastomer product or to a non-elastomer product.
    (vii) The results for each change made to a predominant use 
determination made under Sec.  63.480(g) for a storage vessel that is 
assigned to an affected source subject to this subpart after the 
change.
    (viii) The results for each change made to a predominant use 
determination made under Sec.  63.480(h) for recovery operations 
equipment assigned to an affected source subject to this subpart after 
the change.
    (ix) An owner or operator complying with paragraph (h)(1) of this 
section shall notify the Administrator of the election to comply with 
paragraph (h)(1) of this section as part of the Periodic Report or as 
part of the Notification of Compliance Status as specified in paragraph 
(e)(5)(xi) of this section.
    (x) An owner or operator electing not to retain daily average or 
batch cycle daily average values under paragraph (h)(2) of this section 
shall notify the Administrator as specified in paragraph (h)(2)(i) of 
this section.
    (xi) The owner or operator of an affected source shall submit 
quarterly reports for all emission points included in an emissions 
average as specified in paragraphs (e)(6)(xi)(A) through (C) of this 
section.
    (A) The quarterly reports shall be submitted no later than 60 days 
after the end of each quarter. The first report shall be submitted with 
the Notification of Compliance Status no later than 150 days after the 
compliance date.
    (B) The quarterly reports shall include the information specified 
in paragraphs (e)(6)(xi)(B)(1) through (e)(6)(xi)(B)(7) of this section 
for all emission points included in an emissions average.
    (1) The credits and debits calculated each month during the 
quarter;
    (2) A demonstration that debits calculated for the quarter are not 
more than 1.30 times the credits calculated for the quarter, as 
required under Sec.  63.503(e)(4);
    (3) The values of any inputs to the debit and credit equations in 
Sec.  63.503(g) and (h) that change from month to month during the 
quarter or that have changed since the previous quarter;
    (4) Except as specified in paragraph (i) of this section, results 
of any performance tests conducted during the reporting period 
including one complete report for each test method used for a 
particular kind of emission point as described in paragraph (e)(6)(v) 
of this section. If the performance test was submitted to CEDRI, 
include the unit(s) tested, the pollutant(s) tested, and the date of 
the performance test(s) in the quarterly report. The performance test 
results must be submitted to CEDRI by the date the quarterly report is 
due;
    (5) Reports of daily average values or batch cycle daily averages 
of monitored parameters for excursions as defined in Sec.  63.505(g) or 
(h) and the date of the excursion;
    (6) For excursions caused by lack of monitoring data, the start 
date and time and duration in hours of periods when monitoring data 
were not collected shall be specified; and
    (7) Any other information the affected source is required to report 
under the operating permit or Emissions Averaging Plan for the affected 
source.
    (C) Every fourth quarterly report shall include the following:
    (1) A demonstration that annual credits are greater than or equal 
to annual debits as required by Sec.  63.503(e)(3); and
    (2) A certification of compliance with all the emissions averaging 
provisions in Sec.  63.503.
    (xii) The owner or operator of an affected source shall submit 
quarterly reports for particular emission points and process sections 
not included in an emissions average as specified in paragraphs 
(e)(6)(xii)(A) through (D) of this section.
    (A) The owner or operator of an affected source shall submit 
quarterly reports for a period of 1 year for an emission point or 
process section that is not included in an emissions average if:
    (1) A control or recovery device for a particular emission point or 
process section has more excursions, as defined in Sec.  63.505(g) or 
(h), than the number of excused excursions allowed under Sec.  
63.505(i) for a semiannual reporting period; or
    (2) The Administrator requests that the owner or operator submit 
quarterly reports for the emission point or process section.
    (B) The quarterly reports shall include all information specified 
in paragraphs (e)(6)(iii) through (ix) of this section, as applicable 
to the emission point or process section for which quarterly reporting 
is required under paragraph (e)(6)(xii)(A) of this section. Information 
applicable to other emission points within the affected source shall be 
submitted in the semiannual reports required under paragraph (e)(6)(i) 
of this section.
    (C) Quarterly reports shall be submitted no later than 60 days 
after the end of each quarter.
    (D) After quarterly reports have been submitted for an emission 
point for 1 year without more excursions occurring (during that year) 
than the number of excused excursions allowed under Sec.  63.505(i), 
the owner or operator may return to semiannual reporting for the 
emission point or process section.
    (xiii) The information specified in Sec.  63.108(l)(2).
    (7) Other reports. Other reports shall be submitted as specified in 
paragraphs (e)(7)(i) through (vi) of this section.
* * * * *
    (vi) For fenceline monitoring systems subject to Sec.  63.184, each 
owner or operator must submit the Fenceline Monitoring Reports required 
by Sec.  63.182(e) on a quarterly basis following the procedures 
specified in Sec.  63.182(e).
* * * * *
    (i)(1) Except as specified in paragraph (i)(3) of this section, as 
of January 1, 2012, and within 60 days after the date of completing 
each performance test, as defined in Sec.  63.2 and as required in this 
subpart, you must submit performance test data, except opacity data, 
electronically to EPA's Central Data Exchange by using the Electronic 
Reporting Tool (ERT) (see http://www.epa.gov/ttn/chief/ert/erttool.html/) or other compatible electronic spreadsheet. Only data 
collected using test methods compatible with ERT are subject to this 
requirement to be submitted electronically into EPA's WebFIRE database.
* * * * *
    (3) Beginning no later than July 15, 2024, owners and operators 
must submit performance test reports in accordance with this paragraph. 
Unless otherwise specified in this subpart, within 60 days after the 
date of completing each performance test required by this

[[Page 43261]]

subpart, owners and operators must submit the results of the 
performance test following the procedures specified in Sec.  63.9(k). 
Data collected using test methods supported by the EPA's Electronic 
Reporting Tool (ERT) as listed on the EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test must be submitted in a file format 
generated through the use of the EPA's ERT. Alternatively, owners and 
operators may submit an electronic file consistent with the extensible 
markup language (XML) schema listed on the EPA's ERT website. Data 
collected using test methods that are not supported by the EPA's ERT as 
listed on the EPA's ERT website at the time of the test must be 
included as an attachment in the ERT or alternate electronic file.

0
144. Amend Sec.  63.507 by revising paragraph (c) introductory text and 
adding paragraphs (c)(5) and (6) to read as follows:


Sec.  63.507  Implementation and enforcement.

* * * * *
    (c) The authorities that cannot be delegated to State, local, or 
Tribal agencies are as specified in paragraphs (c)(1) through (6) of 
this section.
* * * * *
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.
    (6) Approval of an extension request under Sec.  63.6(i)(4)(ii).

0
145. Add Sec.  63.508 to read as follows:


Sec.  63.508  Flare requirements.

    (a) For any flare that is used to reduce organic HAP emissions from 
an EPPU, the owner or operator may elect to comply with the 
requirements in this section in lieu of the requirements of Sec.  
63.11(b) and the requirements referenced therein. The owner or operator 
may also elect to comply with the requirements in this section pursuant 
to the overlap provisions provided in Sec.  63.481(k)(2). However, 
beginning no later than the compliance dates specified in Sec.  
63.481(n), the provisions specified in paragraphs (a)(1) through (32) 
of this section no longer apply. Instead, if an owner or operator 
reduces organic HAP emissions from an EPPU by venting emissions through 
a closed-vent system to a steam-assisted, air-assisted, or non-assisted 
flare, then the owner or operator must meet the applicable requirements 
for flares as specified in Sec. Sec.  63.670 and 63.671, including the 
provisions in tables 12 and 13 to subpart CC of this part, except as 
specified in paragraph (b) of this section. This requirement also 
applies to any flare using fuel gas from a fuel gas system, of which 50 
percent or more of the fuel gas is derived from a EPPU, as determined 
on an annual average basis. For purposes of compliance with this 
paragraph, the following terms are defined in Sec.  63.641 of subpart 
CC of this part: Assist air, assist steam, center steam, combustion 
zone, combustion zone gas, flare, flare purge gas, flare supplemental 
gas, flare sweep gas, flare vent gas, lower steam, net heating value, 
perimeter assist air, pilot gas, premix assist air, total steam, and 
upper steam.
    (1) Sec. Sec.  63.487(a)(1)(i) and (b)(1)(i);
    (2) Sec.  63.489(b)(2);
    (3) Sec.  63.490(a)(1);
    (4) Sec. Sec.  63.491(b)(3)(i) through (b)(3)(iii);
    (5) Sec.  63.494(d);
    (6) Sec.  63.496(b)(7)(i)(A);
    (7) Sec.  63.497(a)(2);
    (8) Sec.  63.498(d)(5)(ii)(E);
    (9) Sec.  63.502(k)(1);
    (10) Sec. Sec.  63.504(c)(1) through (c)(3);
    (11) Sec.  63.107(h)(9)(i) related to criteria in Sec.  63.11(b);
    (12) Sec.  63.113(a)(1);
    (13) Sec.  63.114(a)(2);
    (14) Sec. Sec.  63.116(a)(1) through (a)(3);
    (15) Sec. Sec.  63.117(a)(5)(i) through (a)(5)(iii);
    (16) Sec.  63.118(f)(5);
    (17) The last sentence in Sec.  63.119(e)(1);
    (18) Sec. Sec.  63.120(e)(1) through (e)(6);
    (19) Sec. Sec.  63.122(c)(2) and (g)(3);
    (20) Sec.  63.126(b)(2)(i);
    (21) Sec.  63.127(a)(2);
    (22) Sec. Sec.  63.128(b)(1) through (b)(3);
    (23) Sec. Sec.  63.129(a)(5)(i) through (a)(5)(iii);
    (24) Sec. Sec.  63.130(a)(2)(i), (c), and (d)(5);
    (25) Sec. Sec.  63.139(c)(3) and (d)(3);
    (26) Sec. Sec.  63.145(j)(1) through (j)(3);
    (27) Sec. Sec.  63.146(b)(7)(i)(A) through (b)(7)(i)(C);
    (28) Sec.  63.147(d)(1);
    (29) Sec. Sec.  63.172(d);
    (30) Sec. Sec.  63.180(e)(1) through (e)(3);
    (31) Sec.  63.181(g)(1)(iii); and
    (32) The phrase ``including periods when a flare pilot light system 
does not have a flame'' in Sec.  63.181(g)(2)(i).
    (b) The exceptions specified in paragraphs (b) through (o) of Sec.  
63.108 apply, except as specified in paragraphs (b)(1) through (5) of 
this section.
    (1) Where the term ``chemical manufacturing process unit'' is used, 
the term ``EPPU'' applies instead for the purposes of this subpart.
    (2) Where the reference ``Sec.  63.100(k)(10)'' is used, the 
reference Sec.  63.481(n) applies instead for the purposes of this 
subpart.
    (3) Where the phrase ``Hazardous Organic Chemical Manufacturing'' 
is used, the phrase ``Polymers and Resins'' applies instead for the 
purposes of this subpart.
    (4) Where the reference ``Sec.  63.152(b)(7) of subpart G of this 
part'' is used, the reference ``Sec.  63.506(e)(5)(xiii)'' applies 
instead for the purposes of this subpart.
    (5) Section 63.108(i) does not apply.

0
146. Add Sec.  63.509 to read as follows:


Sec.  63.509  Procedures for determining whether process vents, storage 
vessels, or wastewater are in chloroprene service.

    This section applies beginning no later than the compliance dates 
specified in Sec.  63.481(o). To determine if process vents, storage 
vessels, or wastewater in a process at affected sources producing 
neoprene are in chloroprene service, as defined in Sec.  63.482, owners 
and operators must comply with the requirements in paragraphs (a) 
through (c) of this section, as applicable.
    (a) For each continuous front-end process vent, each batch front-
end process vent, and each back-end process vent in a process at 
affected sources producing neoprene, owners and operators must measure 
the flow rate and concentration of chloroprene of each process vent as 
specified in paragraphs (a)(1) through (5) of this section.
    (1) Measurements must be made prior to any dilution of the vent 
streams.
    (2) Measurements may be made on the combined vent streams at an 
elastomer product process unit or for each separate vent stream.
    (3) The sampling site shall be after the last recovery device (if 
any recovery devices are present) but prior to the inlet of any control 
device that is present and prior to release to the atmosphere. Method 1 
or 1A of appendix A-1 to 40 CFR part 60, as appropriate, must be used 
for the selection of the sampling sites. For vents smaller than 0.10 
meter in diameter, sample at one point at the center of the duct.
    (4) The gas volumetric flow rate must be determined using Method 2, 
2A, 2C, 2D, 2F, or 2G of appendices A-1 and A-2 to 40 CFR part 60, as 
appropriate.
    (5) Except as specified in paragraph (a)(6) of this section, the 
concentration of chloroprene must be determined using Method 18 of 
appendix A-6 to 40 CFR part 60 or Method 320 of appendix A to this 
part.
    (6) You may elect to use ASTM D6348-12 (Reapproved 2020) 
(incorporated by reference, Sec.  63.14) in lieu of Method 320 of 
appendix A to this part as specified in paragraph (a)(5) of this 
section. To comply with this

[[Page 43262]]

paragraph, Annexes Al through A8 to ASTM D6348-12 (Reapproved 2020) are 
mandatory; the percent (%) R must be determined for each target analyte 
using Equation A5.5 of ASTM D6348-12 (Reapproved 2020) Annex A5 
(Analyte Spiking Technique); and in order for the test data to be 
acceptable for a compound, the %R must be 70% >= R <= 130%. If the %R 
value does not meet this criterion for a target compound, then the test 
data is not acceptable for that compound and the test must be repeated 
for that analyte (i.e., the sampling and/or analytical procedure should 
be adjusted before a retest). The %R value for each compound must be 
reported in the test report, and all field measurements must be 
corrected with the calculated %R value for that compound by using the 
following equation:
Equation 1 to Paragraph (a)(6)
Reported Results = (Measured Concentration in the Stack x 100)/%R.
    (b) For storage vessels in a process at affected sources producing 
neoprene, owners and operators must determine the concentration of 
chloroprene of the fluid stored in the storage vessels by complying 
with the requirements in paragraph (b)(1) or (2) of this section.
    (1) The owner or operator must measure concentration of chloroprene 
of the fluid stored in the storage vessel using Method 624.1 of 
appendix A to 40 CFR part 136 or preparation by Method SW-846-5030B 
(incorporated by reference, see Sec.  63.14) and analysis by Method SW-
846-8260D (incorporated by reference, see Sec.  63.14). If owners and 
operators collect a sample from a pressure vessel, then the owner or 
operator must maintain the sample under pressure both during and 
following sampling.
    (2) Unless specified by the Administrator, the owner or operator 
may calculate the concentration of chloroprene of the fluid stored in 
the storage vessels if information specific to the fluid stored is 
available. Information specific to the fluid stored includes 
concentration data from safety data sheets.
    (c) For wastewater in a process at affected sources producing 
neoprene, owners and operators must measure concentration of 
chloroprene of the fluid stored in the storage vessel using Method 
624.1 of appendix A to 40 CFR part 136, or preparation by Method SW-
846-5030B (incorporated by reference, see Sec.  63.14) and analysis by 
Method SW-846-8260D (incorporated by reference, see Sec.  63.14). If 
owners and operators collect a sample from a pressure vessel, then the 
owner or operator must maintain the sample under pressure both during 
and following sampling.

0
147. Add Sec.  63.510 to read as follows:


Sec.  63.510  Process vents, storage vessels, and wastewater that are 
in chloroprene service--procedures to determine compliance.

    This section applies beginning no later than the compliance dates 
specified in Sec.  63.481(o). In order to demonstrate compliance with 
the emission limits and work practice standards specified in Sec.  
63.485(y) (for continuous front-end process vents in chloroprene 
service), Sec.  63.487(j) (for batch front-end process vents in 
chloroprene service), Sec.  63.494(a)(7) (for back-end process vents in 
chloroprene service), Sec.  63.484(u) (for storage vessels in 
chloroprene service), and Sec.  63.501(a)(10)(iv) (for wastewater in 
chloroprene service), owners and operators must meet the requirements 
specified in paragraphs (a) and (b) of this section.
    (a) For initial compliance, owners and operators must comply with 
paragraphs (a)(1) through (4) of this section, as applicable.
    (1) [Reserved]
    (2) If an owner or operator chooses to reduce emissions of 
chloroprene by venting emissions through a closed vent system to a non-
flare control device that reduces chloroprene by greater than or equal 
to 98 percent by weight as specified in Sec.  63.484(u), Sec.  
63.485(y), Sec.  63.487(j), or Sec.  63.494(a)(7) then the owner or 
operator must comply with Sec.  63.148 and paragraphs (a)(2)(i) through 
(viii) of this section.
    (i) Conduct an initial performance test of the control device that 
is used to comply with the percent reduction requirement at the inlet 
and outlet of the control device. For purposes of compliance with this 
paragraph, owners and operators may not use a design evaluation. This 
paragraph does not apply if the conditions specified in paragraphs 
(a)(2)(i)(A) through (D) of this section are met for a previously-
conducted measurement or performance test.
    (A) No changes have been made to the process since the time of the 
measurement or performance test;
    (B) The operating conditions and test methods used during 
measurement or performance test conform to the chloroprene related 
requirements of this subpart;
    (C) The control device and process parameter values established 
during the previously-conducted measurement or performance test are 
used to demonstrate continuous compliance with the chloroprene related 
requirements of this subpart; and
    (D) The previously-conducted measurement or performance test was 
completed within the last 60 months.
    (ii) Conduct the performance test according to the procedures in 
Sec.  63.504 and in Sec.  63.116(c). Except as specified in Sec.  
63.509(a)(6), use Method 18 of 40 CFR part 60, appendix A-6 or Method 
320 of appendix A to this part to determine the chloroprene 
concentration. Use Method 1 or 1A of 40 CFR part 60, appendix A-1 to 
select the sampling sites at each sampling location. Determine the gas 
volumetric flowrate using Method 2, 2A, 2C, or 2D of 40 CFR part 60, 
appendix A-2. Use Method 4 of 40 CFR part 60, appendix A-3 to convert 
the volumetric flowrate to a dry basis.
    (iii) Calculate the mass emission rate of chloroprene entering the 
control device and exiting the control device using Equations 1 and 2 
to this paragraph.
Equations 1 and 2 to Paragraph (a)(2)(iii)
E,inlet = K C,inlet M Qinlet (Eq. 1)
E,outlet = K C,outlet M Qoutlet (Eq. 
2)

Where:

E,inlet, E,outlet = Mass rate of chloroprene 
at the inlet and outlet of the control device, respectively, 
kilogram per hour.
C,inlet, C,outlet = Concentration of 
chloroprene in the gas stream at the inlet and outlet of the control 
device, respectively, dry basis, parts per million by volume.
M = Molecular weight of chloroprene, 88.54 grams per gram-mole.
Qinlet, Qoutlet = Flow rate of the gas stream 
at the inlet and outlet of the control device, respectively, dry 
standard cubic meter per minute.
K = Constant, 2.494 x 10-6 (parts per million)-1 (gram-mole per 
standard cubic meter) (kilogram per gram) (minutes per hour), where 
standard temperature (gram-mole per standard cubic meter) is 20 
[deg]C.

    (iv) Calculate the percent reduction from the control device using 
equation 3 to this paragraph. An owner or operator has demonstrated 
initial compliance with Sec.  63.113(j)(2) or Sec.  63.119(a)(5)(ii) if 
the overall reduction of chloroprene is greater than or equal to 98 
percent by weight.
Equation 3 to Paragraph (a)(2)(iv)
Percent reduction = (E,inlet-E,outlet)/
E,inlet * 100 (Eq. 3)

Where:

E,inlet, E,outlet = Mass rate of chloroprene 
at the inlet and outlet of the control device, respectively, 
kilogram per hour, calculated using Equations 5 and 6 to paragraph 
(a)(2)(iii) of this section.


[[Page 43263]]


    (v) If a new control device is installed, then conduct a 
performance test of the new device following the procedures in 
paragraphs (a)(2)(i) through (iv) of this section.
    (vi) [Reserved]
    (vii) If an owner or operator vents emissions through a closed vent 
system to a thermal oxidizer, then the owner or operator must establish 
operating parameter limits by monitoring the operating parameters 
specified in paragraphs (a)(2)(vii)(A) and (B) of this section during 
the performance test.
    (A) Combustion chamber temperature. Determine the average 
combustion chamber temperature during the performance test as the 
average of the test run averages.
    (B) Flue gas flow rate. Determine the average flue gas flow rate 
during the performance test as the average of the test run averages.
    (viii) If an owner or operator vents emissions through a closed 
vent system to a control device other than a thermal oxidizer, then the 
owner or operator must notify the Administrator of the operating 
parameters that are planned to be monitored during the performance test 
prior to establishing operating parameter limits for the control 
device.
    (3) If an owner or operator chooses to reduce emissions of 
chloroprene by venting emissions through a closed vent system to a non-
flare control device that reduces chloroprene to less than 1 ppmv as 
specified in Sec.  63.484(u), Sec.  63.485(y), Sec.  63.487(j), or 
Sec.  63.494(a)(7) then the owner or operator must comply with Sec.  
63.148 and either paragraph (a)(3)(i) or (ii) of this section.
    (i) Install an FTIR CEMS meeting the requirements of Performance 
Specification 15 of 40 CFR part 60, appendix B to continuously monitor 
the chloroprene concentration at the exit of the control device. Comply 
with the requirements specified in Sec.  63.2450(j) for CEMS.
    (ii) If the owner or operator does not install a CEMS under 
paragraph (a)(3)(i) of this section, then the owner or operator must 
comply with paragraphs (a)(3)(ii)(A) through (C) of this section.
    (A) Conduct an initial performance test at the outlet of the 
control device that is used to comply with the concentration 
requirement.
    (B) Conduct the performance test according to the procedures in 
Sec.  63.504 and in Sec.  63.116(c). Except as specified in Sec.  
63.509(a)(6), use Method 18 of 40 CFR part 60, appendix A-6 or Method 
320 of appendix A to this part to determine the chloroprene 
concentration. If the non-flare control device is a combustion device, 
correct the chloroprene concentration to 3 percent oxygen according to 
Sec.  63.116(c)(iii)(B), except ``TOC or organic HAP'' and ``TOC (minus 
methane and ethane) or organic HAP'' in the Variables Cc and Cm must be 
replaced with ``chloroprene''. An owner or operator has demonstrated 
initial compliance with Sec.  63.484(u), Sec.  63.485(y), Sec.  
63.487(j), or Sec.  63.494(a)(7) if the chloroprene concentration is 
less than 1 ppmv.
    (C) Comply with the requirements specified in paragraphs (a)(2)(v) 
through (viii) of this section, as applicable.
    (4) If owners and operators choose to reduce emissions of 
chloroprene by venting emissions through a closed vent system to a non-
flare control device that reduces chloroprene to less than 5 pounds per 
year for all combined process vents within the process as specified in 
Sec.  63.113(j)(2), then the owner or operator must comply with Sec.  
63.148 and paragraphs (a)(4)(i) through (iv) of this section.
    (i) Conduct an initial performance test of the control device that 
is used to comply with the mass emission limit requirement at the 
outlet of the control device.
    (ii) Conduct the performance test according to the procedures in 
Sec.  63.504 and in Sec.  63.116(c). Except as specified in Sec.  
63.509(a)(6), use Method 18 of 40 CFR part 60, appendix A-6 or Method 
320 of appendix A to this part to determine the chloroprene 
concentration. Use Method 1 or 1A of 40 CFR part 60, appendix A-1 to 
select the sampling site. Determine the gas volumetric flowrate using 
Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A-2. Use Method 4 
of 40 CFR part 60, appendix A-3 to convert the volumetric flowrate to a 
dry basis.
    (iii) Calculate the mass emission rate of chloroprene exiting the 
control device using Equation 2 to paragraph (a)(2)(iii) of this 
section. An owner or operator has demonstrated initial compliance with 
Sec.  63.113(j)(2) if the chloroprene from all process vents 
(controlled and uncontrolled) within the process is less than 5 pounds 
per year when combined.
    (iv) Comply with the requirements specified in paragraphs (a)(2)(v) 
through (viii) of this section, as applicable.
    (b) For continuous compliance, owners and operators must comply 
with paragraphs (b)(1) through (6) of this section, as applicable.
    (1) [Reserved]
    (2) If you choose to reduce emissions of chloroprene by venting 
emissions through a closed-vent system to a non-flare control device 
that reduces chloroprene to less than 1 ppmv as specified in Sec.  
63.113(j)(2) or Sec.  63.119(a)(5)(ii) of subpart G of this part, and 
you choose to comply with paragraph (a)(3)(i) of this section, then 
continuously monitor the chloroprene concentration at the exit of the 
control device using an FTIR CEMS meeting the requirements of 
Performance Specification 15 of 40 CFR part 60, appendix B and Sec.  
63.2450(j). If an owner or operator uses an FTIR CEMS, then the owner 
or operator does not need to conduct the performance testing required 
in paragraph (b)(3) of this section or the operating parameter 
monitoring required in paragraphs (b)(4) through (6) of this section.
    (3) Conduct a performance test no later than 60 months after the 
previous performance test and reestablish operating parameter limits 
following the procedures in paragraph (a)(2) through (4) of this 
section. The Administrator may request a repeat performance test at any 
time. For purposes of compliance with this paragraph, owners and 
operators may not use a design evaluation.
    (4) [Reserved]
    (5) If an owner or operator vents emissions through a closed vent 
system to a thermal oxidizer, then the owner or operator must comply 
with Sec.  63.148, and the owner or operator must meet the operating 
parameter limits specified in paragraphs (b)(5)(i) and (ii) of this 
section and the requirements in paragraph (b)(5)(iii) of this section.
    (i) Minimum combustion chamber temperature, equal to the average 
combustion chamber temperature measured during the most recent 
performance test. Determine combustion chamber temperature with a 
temperature sensor with a minimum accuracy of at least 1 
percent over the normal range of temperature measured, expressed in 
degrees Celsius, or 2.8 degrees Celsius, whichever is greater. 
Compliance with the minimum combustion chamber temperature operating 
limit must be determined continuously on a 1-hour block basis.
    (ii) Maximum flue gas flow rate, equal to the average flue gas flow 
rate measured during the most recent performance test. Determine flue 
gas flow rate with a flow sensor with a minimum accuracy of at least 
5 percent over the normal range of flow measured, or 280 
liters per minute (10 cubic feet per minute), whichever is greater. 
Compliance with the maximum flue gas flow rate operating limit must be 
determined continuously on a 1-hour block basis.
    (iii) The owner or operator must maintain the thermal oxidizer in 
accordance with good combustion practices that ensure proper

[[Page 43264]]

combustion. Good combustion practices include, but are not limited to, 
proper burner maintenance, proper burner alignment, proper fuel to air 
distribution and mixing, routine inspection, and preventative 
maintenance.
    (6) If an owner or operator vents emissions through a closed vent 
system to a control device other than a thermal oxidizer, then the 
owner or operator must comply with Sec.  63.148, and the owner or 
operator must monitor the operating parameters identified in paragraph 
(a)(2)(viii) of this section and meet the established operating 
parameter limits to ensure continuous compliance. The frequency of 
monitoring and averaging time will be determined based upon the 
information provided to the Administrator.

0
148. Amend Table 1 to Subpart U by revising entry ``Sec.  
63.6(e)(1)(i)'', adding entry ``Sec.  63.7(a)(4)'', revising entries 
``Sec.  63.8(c)(1)(i)'', ``Sec.  63.8(c)(1)(iii)'', ``Sec.  63.9(k)'' 
and ``63.10(d)(5)(i)'', removing entry ``Sec.  63.10(d)(5)(ii)'', 
revising entry ``Sec.  63.11'', and removing note a to read as follows:

       Table 1 to Subpart U of Part 63--Applicability of General Provisions to Subpart U Affected Sources
----------------------------------------------------------------------------------------------------------------
                Reference                    Applies to  subpart U                    Explanation
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Sec.   63.6(e)(1)(i)....................  No.........................  See Sec.   63.483(a) for general duty
                                                                        requirement. Any cross reference to Sec.
                                                                          63.6(e)(1)(i) in any other general
                                                                        provision incorporated by reference
                                                                        shall be treated as a cross reference to
                                                                        Sec.   63.483(a).
 
                                                  * * * * * * *
Sec.   63.6(i)(4)(ii)...................  No; except yes for affected
                                           sources producing neoprene.
 
                                                  * * * * * * *
Sec.   63.7(a)(4).......................  Yes........................
Sec.   63.8(a)(3).......................  No.........................  [Reserved.].
Sec.   63.8(a)(4).......................  Yes, except for flares
                                           subject to Sec.   63.508.
Sec.   63.8(b)(1).......................  Yes........................
Sec.   63.8(b)(2).......................  No.........................  Subpart U specifies locations to conduct
                                                                        monitoring.
Sec.   63.8(b)(3).......................  Yes........................
 
                                                  * * * * * * *
Sec.   63.8(c)(1)(i)....................  Yes, before July 15, 2027.
                                           No, beginning on and after
                                           July 15, 2027.
 
                                                  * * * * * * *
Sec.   63.8(c)(1)(iii)..................  Yes, before July 15, 2027.
                                           No, beginning on and after
                                           July 15, 2027.
 
                                                  * * * * * * *
Sec.   63.9(k)..........................  Yes........................
 
                                                  * * * * * * *
63.10(d)(5).............................  No.........................
 
                                                  * * * * * * *
Sec.   63.11............................  Yes........................  Except for flares subject to Sec.
                                                                        63.508, Sec.   63.11(b) specifies
                                                                        requirements for flares used to comply
                                                                        with provisions of this subpart. Sec.
                                                                        63.504(c) contains the requirements to
                                                                        conduct compliance demonstrations for
                                                                        flares subject to this subpart that are
                                                                        not subject to Sec.   63.508. Sec.
                                                                        63.11(c), (d), and (e) specifies
                                                                        requirements for an alternative work
                                                                        practice for equipment leaks.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------


0
149. Revise table 6 to subpart U to read as follows:

 Table 6 to Subpart U of Part 63--Group 1 Batch Front-End Process Vents
    and Aggregate Batch Vent Streams--Monitoring, Recordkeeping, and
                         Reporting Requirements
------------------------------------------------------------------------
                                                      Recordkeeping and
                                                          reporting
    Control/recovery device        Parameter to be     requirements for
                                      monitored           monitored
                                                          parameters
------------------------------------------------------------------------
Thermal incinerators other than  Firebox             1. Continuous
 those used for vents in          temperature \a\.    records as
 chloroprene service.                                 specified in Sec.
                                                       63.491(e)(1).\b\
                                                     2. Record and
                                                      report the average
                                                      firebox
                                                      temperature
                                                      measured during
                                                      the performance
                                                      test--NCS.\c\

[[Page 43265]]

 
                                                     3. Record the batch
                                                      cycle daily
                                                      average firebox
                                                      temperature as
                                                      specified in Sec.
                                                       63.491(e)(2).
                                                     4. Report all batch
                                                      cycle daily
                                                      average
                                                      temperatures that
                                                      are below the
                                                      minimum operating
                                                      value established
                                                      in the NCS or
                                                      operating permit
                                                      and all instances
                                                      when monitoring
                                                      data are not
                                                      collected--PR.\d\
                                                      \e\
Thermal oxidizers used for       a. Combustion       1. Continuous
 vents in chloroprene service.    chamber             records as
                                  temperature.        specified in Sec.
                                                       63.491(e)(1).\b\
                                                     2. Record and
                                                      report the average
                                                      firebox
                                                      temperature
                                                      measured during
                                                      the performance
                                                      test--NCS.\c\
                                                     3. Record the 1-
                                                      hour block average
                                                      firebox
                                                      temperature as
                                                      specified in Sec.
                                                       63.510(b)(5)(i).
                                                     4. Report all 1-
                                                      hour block average
                                                      temperatures that
                                                      are below the
                                                      minimum operating
                                                      value established
                                                      in the NCS or
                                                      operating permit
                                                      and all instances
                                                      when monitoring
                                                      data are not
                                                      collected--PR.\d\
                                                      \e\
                                 b. Flue gas flow    1. Continuous
                                  rate.               records as
                                                      specified in Sec.
                                                       63.491(e)(1).\b\
                                                     2. Record and
                                                      report the average
                                                      flue gas flow rate
                                                      measured during
                                                      the performance
                                                      test--NCS.\c\
                                                     3. Record the 1-
                                                      hour block average
                                                      flue gas flow rate
                                                      as specified in
                                                      Sec.
                                                      63.510(b)(5)(ii).
                                                     4. Report all 1-
                                                      hour block average
                                                      flow rates that
                                                      are above the
                                                      maximum operating
                                                      value established
                                                      in the NCS or
                                                      operating permit
                                                      and all instances
                                                      when monitoring
                                                      data are not
                                                      collected--PR.\d\
                                                      \e\
Catalytic incinerator..........  Temperature         1. Continuous
                                  upstream and        records as
                                  downstream of the   specified in Sec.
                                  catalyst bed.        63.491(e)(1).\b\
                                                     2. Record and
                                                      report the average
                                                      upstream and
                                                      downstream
                                                      temperatures and
                                                      the average
                                                      temperature
                                                      difference across
                                                      the catalyst bed
                                                      measured during
                                                      the performance
                                                      test--NCS.\c\
                                                     3. Record the batch
                                                      cycle daily
                                                      average upstream
                                                      temperature and
                                                      temperature
                                                      difference across
                                                      catalyst bed as
                                                      specified in Sec.
                                                       63.491(e)(2).
                                                     4. Report all batch
                                                      cycle daily
                                                      average upstream
                                                      temperatures that
                                                      are below the
                                                      minimum upstream
                                                      value established
                                                      in the NCS or
                                                      operating permit--
                                                      PR.\d\ \e\
                                                     5. Reporting all
                                                      batch cycle daily
                                                      average
                                                      temperature
                                                      differences across
                                                      the catalyst bed
                                                      that are below the
                                                      minimum difference
                                                      established in the
                                                      NCS or operating
                                                      permit--PR.\d\ \e\
                                                     6. Report all
                                                      instances when
                                                      monitoring data
                                                      are not collected.
Boiler or process heater with a  Firebox             1. Continuous
 design heat input capacity       temperature \a\.    records as
 less than 44 megawatts and                           specified in Sec.
 where the batch front--end                            63.491(e)(1).\b\
 process vents or aggregate
 batch vent streams are ``not''
 introduced with or used as the
 primary fuel.
                                                     2. Record and
                                                      report the average
                                                      firebox
                                                      temperature
                                                      measured during
                                                      the performance
                                                      test--NCS.\c\
                                                     3. Record the batch
                                                      cycle daily
                                                      average firebox
                                                      temperature as
                                                      specified in Sec.
                                                       63.491(e)(2).\d\
                                                     4. Report all batch
                                                      cycle daily
                                                      average
                                                      temperatures that
                                                      are below the
                                                      minimum operating
                                                      value established
                                                      in the NCS or
                                                      operating permit
                                                      and all instances
                                                      when monitoring
                                                      data are not
                                                      collected--PR.\d\
                                                      \e\
Flare (if meeting the            Presence of a       1. Hourly records
 requirements of Sec.             flame at the        of whether the
 63.487(a)(1)(i) or (b)(1)(i)).   pilot light.        monitor was
                                                      continuously
                                                      operating during
                                                      light batch
                                                      emission episodes
                                                      selected for
                                                      control and
                                                      whether a flame
                                                      was continuously
                                                      present at the
                                                      pilot light during
                                                      each hour.
                                                     2. Record and
                                                      report the
                                                      presence of a
                                                      flame at the pilot
                                                      light over the
                                                      full period of the
                                                      compliance
                                                      determination--NCS
                                                      .\c\
                                                     3. Record the times
                                                      and durations of
                                                      all periods during
                                                      batch emission
                                                      episodes when all
                                                      flames at the
                                                      pilot light of a
                                                      flare are absent
                                                      or the monitor is
                                                      not operating.
                                                     4. Report the times
                                                      and durations of
                                                      all periods during
                                                      batch emission
                                                      episodes selected
                                                      for control when
                                                      all flames at the
                                                      pilot light of a
                                                      flare are absent--
                                                      PR.\d\
Flare (if meeting the            The parameters are  1. Records as
 requirements of Sec.             specified in        specified in
 63.487(a)(1)(iii) or             paragraphs (b)      paragraph (m) of
 (b)(1)(iii)).                    through (o) of      Sec.   63.108 and
                                  Sec.   63.108 and   Sec.   63.508.
                                  Sec.   63.508.     2. Report
                                                      information as
                                                      specified in in
                                                      paragraph (l) of
                                                      Sec.   63.108 and
                                                      Sec.   63.508--PR.
Scrubber for halogenated batch   a. pH of scrubber   1. Continuous
 front-end process vents or       effluent, and.      records as
 aggregate batch vent streams                         specified in Sec.
 (Note: Controlled by a                                63.491(e)(1).\b\
 combustion device other than a                      2. Record and
 flare).                                              report the average
                                                      pH of the scrubber
                                                      effluent measured
                                                      during the
                                                      performance test--
                                                      NCS.\c\
                                                     3. Record the batch
                                                      cycle daily
                                                      average pH of the
                                                      scrubber effluent
                                                      as specified in
                                                      Sec.
                                                      63.491(e)(2).
                                                     4. Report all batch
                                                      cycle daily
                                                      average pH values
                                                      of the scrubber
                                                      effluent that are
                                                      below the minimum
                                                      operating value
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      instances when
                                                      insufficient
                                                      monitoring data
                                                      are collected--
                                                      PR.\d\ \e\
                                 b. Scrubber liquid  1. Records as
                                  and gas flow        specified in Sec.
                                  rates (Sec.          63.491(e)(1).\b\
                                  63.489(b)(4)(ii)). 2. Record and
                                                      report the
                                                      scrubber liquid/
                                                      gas ratio averaged
                                                      over the full
                                                      period of the
                                                      performance test--
                                                      NCS.\c\
                                                     3. Record the batch
                                                      cycle daily
                                                      average scrubber
                                                      liquid/gas ratio
                                                      as specified in
                                                      Sec.
                                                      63.491(e)(2).

[[Page 43266]]

 
                                                     4. Report all batch
                                                      cycle daily
                                                      average scrubber
                                                      liquid/gas ratios
                                                      that are below the
                                                      minimum value
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      instances when
                                                      insufficient
                                                      monitoring data
                                                      are collected--
                                                      PR.\d\ \e\
Absorber \f\...................  a. Exit             1. Continuous
                                  temperature of      records as
                                  the absorbing       specified in Sec.
                                  liquid, and.         63.491(e)(1).\b\
                                                     2. Record and
                                                      report the average
                                                      exit temperature
                                                      of the absorbing
                                                      liquid measured
                                                      during the
                                                      performance test--
                                                      NCS.\c\
                                                     3. Record the batch
                                                      cycle daily
                                                      average exit
                                                      temperature of the
                                                      absorbing liquid
                                                      as specified in
                                                      Sec.
                                                      63.491(e)(2) for
                                                      each batch cycle.
                                                     4. Report all the
                                                      batch cycle daily
                                                      average exit
                                                      temperatures of
                                                      the absorbing
                                                      liquid that are
                                                      above the maximum
                                                      operating
                                                      temperature
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      instances when
                                                      monitoring data
                                                      are not collected--
                                                      PR.\d\ \e\
                                 b. Exit specific    1. Continuous
                                  gravity of the      records as
                                  absorbing liquid.   specified in Sec.
                                                       63.491(e)(1).\b\
                                                     2. Record and
                                                      report the average
                                                      exit specific
                                                      gravity measured
                                                      during the
                                                      performance test--
                                                      NCS.
                                                     3. Record the batch
                                                      cycle daily
                                                      average exit
                                                      specific gravity
                                                      as specified in
                                                      Sec.
                                                      63.491(e)(2).
                                                     4. Report all batch
                                                      cycle daily
                                                      average exit
                                                      specific gravity
                                                      values that are
                                                      below the minimum
                                                      operating value
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      instances when
                                                      monitoring data
                                                      are not collected--
                                                      PR.\d\ \e\
Condenser \f\..................  Exit (product       1. Continuous
                                  side) temperature.  records as
                                                      specified in Sec.
                                                       63.491(e)(1) \b\
                                                     2. Record and
                                                      report the average
                                                      exit temperature
                                                      measured during
                                                      the performance
                                                      test--NCS.
                                                     3. Record the batch
                                                      cycle daily
                                                      average exit
                                                      temperature as
                                                      specified in Sec.
                                                       63.491(e)(2).
                                                     4. Report all batch
                                                      cycle daily
                                                      average exit
                                                      temperatures that
                                                      are above the
                                                      maximum operating
                                                      value established
                                                      in the NCS or
                                                      operating permit
                                                      and all instances
                                                      when monitoring
                                                      data are not
                                                      collected--PR.\d\
                                                      \e\
Carbon adsorber \f\............  a. Total            1. Record of total
                                  regeneration        regeneration steam
                                  steam flow or       flow or nitrogen
                                  nitrogen flow, or   flow, or pressure
                                  pressure gauge or   for each carbon
                                  absolute) during    bed regeneration
                                  carbon bed          cycle.
                                  regeneration
                                  cycle(s), and.
                                                     2. Record and
                                                      report the total
                                                      regeneration steam
                                                      flow or nitrogen
                                                      flow, or pressure
                                                      during each carbon
                                                      bed regeneration
                                                      cycle during the
                                                      performance test--
                                                      NCS.\c\
                                                     3. Report all
                                                      carbon bed
                                                      regeneration
                                                      cycles when the
                                                      total regeneration
                                                      steam flow or
                                                      nitrogen flow, or
                                                      pressure is above
                                                      the maximum value
                                                      established in the
                                                      NCS or operating
                                                      permit--PR.\d\ \e\
                                 b. Temperature of   1. Record the
                                  the carbon bed      temperature of the
                                  after               carbon bed after
                                  regeneration and    each regeneration
                                  within 15 minutes   and within 15
                                  of completing any   minutes of
                                  cooling cycle(s).   completing any
                                                      cooling cycle(s).
                                                     2. Record and
                                                      report the
                                                      temperature of the
                                                      carbon bed after
                                                      each regeneration
                                                      and within 15
                                                      minutes of
                                                      completing any
                                                      cooling cycle(s)
                                                      measured during
                                                      the performance
                                                      test--NCS.\c\
                                                     3. Report all
                                                      carbon bed
                                                      regeneration
                                                      cycles when the
                                                      temperature of the
                                                      carbon bed after
                                                      regeneration, or
                                                      within 15 minutes
                                                      of completing any
                                                      cooling cycle(s),
                                                      is above the
                                                      maximum value
                                                      established in the
                                                      NCS or operating
                                                      permit--PR.\d\ \e\
                                 Outlet HAP or TOC   For each
                                  concentration.      nonregenerative
                                                      adsorber and
                                                      regenerative
                                                      adsorber that is
                                                      regenerated
                                                      offsite subject to
                                                      the requirements
                                                      in Sec.
                                                      63.489(b)(10), the
                                                      owner or operator
                                                      must record each
                                                      outlet HAP or TOC
                                                      concentration
                                                      measured according
                                                      to Sec.  Sec.
                                                      63.489(b)(10)(i)
                                                      and (b)(10)(ii).
                                 Adsorbent           1. For each
                                  replacement.        nonregenerative
                                                      adsorber and
                                                      regenerative
                                                      adsorber that is
                                                      regenerated
                                                      offsite subject to
                                                      the requirements
                                                      in Sec.
                                                      63.489(b)(10), the
                                                      owner or operator
                                                      must record date
                                                      and time the
                                                      adsorbent was last
                                                      replaced.
                                 Breakthrough......  For each
                                                      nonregenerative
                                                      adsorber and
                                                      regenerative
                                                      adsorber that is
                                                      regenerated
                                                      offsite subject to
                                                      the requirements
                                                      in Sec.
                                                      63.489(b)(10), the
                                                      owner or operator
                                                      must:
                                                     1. Record
                                                      breakthrough limit
                                                      and bed life
                                                      established
                                                      according to Sec.
                                                       63.489(b)(10)(i).
                                                     2. Report the date
                                                      of each instance
                                                      when breakthrough,
                                                      as defined in Sec.
                                                        63.101, is
                                                      detected between
                                                      the first and
                                                      second adsorber
                                                      and the adsorber
                                                      is not replaced
                                                      according to Sec.
                                                       63.489(b)(10)(iii
                                                      )(A)--PR.\g\
Sorbent injection..............  a. Sorbent          1. Continuous
                                  injection rate.     records as
                                                      specified in Sec.
                                                       63.491(e)(1).\b\
                                                     2. Record and
                                                      report the average
                                                      sorbent injection
                                                      rate measured
                                                      during the
                                                      performance test--
                                                      NCS.\c\
                                                     3. Record the batch
                                                      cycle daily
                                                      average sorbent
                                                      injection rate as
                                                      specified in Sec.
                                                       63.491(e)(2).
                                                     4. Report all batch
                                                      cycle daily
                                                      average sorbent
                                                      injection rates
                                                      that are below the
                                                      minimum value
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      instances when
                                                      insufficient
                                                      monitoring data
                                                      are collected--
                                                      PR.\d\ \e\
                                 b. Carrier gas      1. Continuous
                                  flow rate.          records as
                                                      specified in Sec.
                                                       63.491(e)(1).\b\
                                                     2. Record and
                                                      report the average
                                                      carrier gas flow
                                                      rate measured
                                                      during the
                                                      performance test--
                                                      NCS.\c\

[[Page 43267]]

 
                                                     3. Record the batch
                                                      cycle daily
                                                      average carrier
                                                      gas flow rate as
                                                      specified in Sec.
                                                       63.491(e)(2).
                                                     4. Report all batch
                                                      cycle daily
                                                      average carrier
                                                      gas flow rates
                                                      that are below the
                                                      minimum value
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      instances when
                                                      insufficient
                                                      monitoring data
                                                      are collected--
                                                      PR.\d\ \e\
All control devices............  a. Diversion to     1. Hourly records
                                  the atmosphere      of whether the
                                  from the control    flow indicator was
                                  device or.          operating during
                                                      batch emission
                                                      episodes selected
                                                      for control and
                                                      whether a
                                                      diversion was
                                                      detected at any
                                                      time during the
                                                      hour, as specified
                                                      in Sec.
                                                      63.491(e)(3).
                                                     2. Record and
                                                      report the times
                                                      of all periods
                                                      during batch
                                                      emission episodes
                                                      selected for
                                                      control when
                                                      emissions are
                                                      diverted through a
                                                      bypass line, or
                                                      the flow indicator
                                                      is not operating--
                                                      PR.\d\
                                                     3. For each
                                                      affected source as
                                                      described in Sec.
                                                       63.480, beginning
                                                      no later than the
                                                      compliance dates
                                                      specified in Sec.
                                                       63.481(n), record
                                                      and report the
                                                      start date, start
                                                      time, duration in
                                                      hours, estimate of
                                                      the volume of gas
                                                      in standard cubic
                                                      feet, the
                                                      concentration of
                                                      organic HAP in the
                                                      gas in parts per
                                                      million by volume
                                                      and the resulting
                                                      mass emissions of
                                                      organic HAP in
                                                      pounds that bypass
                                                      a control device.
                                                      For periods when
                                                      the flow indicator
                                                      is not operating,
                                                      report the start
                                                      date, start time,
                                                      and duration in
                                                      hours--PR.\d\
                                 b. Monthly          1. Records that
                                  inspections of      monthly
                                  sealed valves.      inspections were
                                                      performed as
                                                      specified in Sec.
                                                       63.491(e)(4)(i).
                                                     2. Record and
                                                      report all monthly
                                                      inspections that
                                                      show that valves
                                                      are in the
                                                      diverting position
                                                      or that a seal has
                                                      been broken--
                                                      PR.\d\
                                                     3. For each
                                                      affected source as
                                                      described in Sec.
                                                       63.480, beginning
                                                      no later than the
                                                      compliance dates
                                                      specified in Sec.
                                                       63.481(n), record
                                                      and report the
                                                      start date, start
                                                      time, duration in
                                                      hours, estimate of
                                                      the volume of gas
                                                      in standard cubic
                                                      feet, the
                                                      concentration of
                                                      organic HAP in the
                                                      gas in parts per
                                                      million by volume
                                                      and the resulting
                                                      mass emissions of
                                                      organic HAP in
                                                      pounds that bypass
                                                      a control device.
                                                      For periods when
                                                      the flow indicator
                                                      is not operating,
                                                      report the start
                                                      date, start time,
                                                      and duration in
                                                      hours--PR.\d\
Absorber, condenser, and carbon  Concentration       1. Continuous
 adsorber (as an alternative to   level or reading    records as
 the above).                      indicated by an     specified in Sec.
                                  organic              63.491(e)(1).\b\
                                  monitoring device  2. Record and
                                  at the outlet of    report and average
                                  the recovery        batch vent
                                  device.             concentration
                                                      level or reading
                                                      measured during
                                                      the performance
                                                      test--NCS.
                                                     3. Record the batch
                                                      cycle daily
                                                      average
                                                      concentration
                                                      level or reading
                                                      as specified in
                                                      Sec.
                                                      63.491(e)(2).
                                                     4. Report all batch
                                                      cycle daily
                                                      average
                                                      concentration
                                                      levels or readings
                                                      that are above the
                                                      maximum values
                                                      established in the
                                                      NCS or operating
                                                      permit and all
                                                      instances when
                                                      monitoring data
                                                      are not collected--
                                                      PR.\d\ \e\
------------------------------------------------------------------------
\a\ Monitor may be installed in the firebox or in the duct work
  immediately downstream of the firebox before any substantial heat
  exchange is encountered.
\b\ ``Continuous records'' is defined in Sec.   63.111.
\c\ NCS = Notification of Compliance Status described in Sec.
  63.506(e)(5).
\d\ PR = Periodic Reports described in Sec.   63.506(e)(6).
\e\ The periodic reports shall include the duration of periods when
  monitoring data are not collected as specified in Sec.
  63.506(e)(6)(iii)(C).
\f\ Alternatively, these devices may comply with the organic monitoring
  device provisions listed at the end of this table.


0
150. Revise table 7 to subpart U to read as follows:

     Table 7 to Subpart U of Part 63--Operating Parameters for Which
   Monitoring Levels Are Required To Be Established for Continuous and
     Batch Front-End Process Vents and Aggregate Batch Vent Streams
------------------------------------------------------------------------
                                                          Established
    Control/recovery device        Parameters to be        operating
                                      monitored          parameter(s)
------------------------------------------------------------------------
Thermal incinerator............  Firebox temperature  Minimum
                                                       temperature.
Thermal oxidizers used for       Combustion chamber   Minimum
 vents in chloroprene service.    temperature.         temperature.
Thermal oxidizers used for       Flue gas flow rate.  Maximum flue gas
 vents in chloroprene service.                         flow rate.
Catalytic incinerator..........  Temperature          Minimum upstream
                                  upstream and         temperature; and
                                  downstream of the    minimum
                                  catalyst bed.        temperature
                                                       difference across
                                                       the catalyst bed.
Boiler or process heater.......  Firebox temperature  Minimum
                                                       temperature.
Scrubber for halogenated vents.  pH of scrubber       Minimum pH; and
                                  effluent; and        minimum liquid/
                                  scrubber liquid      gas ratio.
                                  and gas flow rates
                                  [Sec.
                                  63.489(b)(4)(ii)].
Absorber.......................  Exit temperature of  Maximum
                                  the absorbing        temperature; and
                                  liquid; and exit     maximum specific
                                  specific gravity     gravity.
                                  of the absorbing
                                  liquid.
Condenser......................  Exit temperature...  Maximum
                                                       temperature.
Carbon adsorber................  Total regeneration   Maximum flow or
                                  steam flow or        pressure; and
                                  nitrogen flow, or    maximum
                                  pressure (gauge or   temperature.
                                  absolute) \a\
                                  during carbon bed
                                  regeneration
                                  cycle; and
                                  temperature of the
                                  carbon bed after
                                  regeneration (and
                                  within 15 minutes
                                  of completing any
                                  cooling cycle(s)).

[[Page 43268]]

 
Sorbent injection..............  Sorbent injection    Minimum injection
                                  rate.                rate.
Sorbent injection..............  Carrier gas flow     Minimum carrier
                                  rate.                gas flow rate.
Other devices (or as an          HAP concentration    Maximum HAP
 alternate to the above) \b\.     level or reading     concentration or
                                  at outlet of         reading.
                                  device.
------------------------------------------------------------------------
\a\ 25 to 50 mm (absolute) is a common pressure level obtained by
  pressure swing absorbers.
\b\ Concentration is measured instead of an operating parameter.


0
151. Amend table 9 to subpart U by adding an entry for Sec.  
63.506(e)(7)(vi) to read as follows:

                    Table 9 to Subpart U of Part 63--Routine Reports Required by This Subpart
----------------------------------------------------------------------------------------------------------------
                Reference                    Description of  report                     Due date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Sec.   63.506(e)(7)(vi).................  Fenceline Monitoring         Quarterly, no later than 45 calendar days
                                           Reports.                     following the end of each quarterly
                                                                        reporting period. See Sec.   63.182(e)
                                                                        of subpart H of this part for the due
                                                                        date for this report.
----------------------------------------------------------------------------------------------------------------
\a\ There may be two versions of this report due at different times; one for equipment subject to Sec.   63.502
  and one for other emission points subject to this subpart.
\b\ There will be two versions of this report due at different times; one for equipment subject to Sec.   63.502
  and one for other emission points subject to this subpart.
\c\ Note that the EPPU remains subject to this subpart until the notification under Sec.   63.480(f)(3)(i) is
  made.


0
152. Add table 10 to subpart U to read as follows:

       Table 10 to Subpart U of Part 63--Toxic Equivalency Factors
------------------------------------------------------------------------
                                                      Toxic equivalency
             Dioxin and Furan Congener                     factor
------------------------------------------------------------------------
1,2,3,7,8-pentachlorodibenzo-p-dioxin.............                     1
1,2,3,4,7,8-hexachlorodibenzo-p-dioxin............                   0.1
1,2,3,7,8,9-hexachlorodibenzo-p-dioxin............                   0.1
1,2,3,6,7,8-hexachlorodibenzo-p-dioxin............                   0.1
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin.........                  0.01
octachlorodibenzo-p-dioxin........................                0.0003
2,3,7,8-tetrachlorodibenzofuran...................                   0.1
2,3,4,7,8-pentachlorodibenzofuran.................                   0.3
1,2,3,7,8-pentachlorodibenzofuran.................                  0.03
1,2,3,4,7,8-hexachlorodibenzofuran................                   0.1
1,2,3,6,7,8-hexachlorodibenzofuran................                   0.1
1,2,3,7,8,9-hexachlorodibenzofuran................                   0.1
2,3,4,6,7,8-hexachlorodibenzofuran................                   0.1
1,2,3,4,6,7,8-heptachlorodibenzofuran.............                  0.01
1,2,3,4,7,8,9-heptachlorodibenzofuran.............                  0.01
Octachlorodibenzofuran............................                0.0003
------------------------------------------------------------------------


0
153. Amend Sec.  63.521 by adding paragraph (c) to read as follows:


Sec.  63.521  Compliance schedule.

* * * * *
    (c) All affected sources that commenced construction or 
reconstruction on or before April 25, 2023, must be in compliance with 
the requirements in Sec.  63.523(d), Sec.  63.524(a)(3), (b)(3), and 
(c), Sec.  63.525(a), (e), (j), (k), and (l), Sec.  63.527(f) and (g), 
and Sec.  63.528(a)(4) upon initial startup or on July 15, 2027, 
whichever is later. All affected sources that commenced construction or 
reconstruction after April 25, 2023, must be in compliance with the 
requirements in Sec.  63.523(d), Sec.  63.524(a)(3), (b)(3), and (c), 
Sec.  63.525(a), (e), (j), (k), and (l), Sec.  63.527(f) and (g), and 
Sec.  63.528(a)(4) upon initial startup, or on July 15, 2024, whichever 
is later.

0
154. Amend Sec.  63.522 by:
0
a. Revising the definition of ``Affected source'';
0
 b. Adding the definition of ``Dioxins and furans'',
0
c. Revising the definition of ``Equipment leaks'' and
0
d. Adding definitions of ``Heat Exchange System'', ``In organic 
hazardous air pollutant or in organic HAP service'' and ``Pressure 
relief device or valve''.

[[Page 43269]]

    The additions and revisions read as follows:


Sec.  63.522  Definitions.

* * * * *
    Affected source means all HAP emission points within a facility 
that are related to the production of BLR or WSR, including process 
vents, storage tanks, wastewater systems, equipment leaks, and heat 
exchange systems.
* * * * *
    Dioxins and furans means total tetra- through octachlorinated 
dibenzo-p-dioxins and dibenzofurans.
* * * * *
    Equipment leaks means, before July 15, 2027, emissions of hazardous 
air pollutants from a connector, pump, compressor, agitator, pressure 
relief device, sampling connection system, open-ended valve or line, or 
instrumentation system in organic hazardous air pollutant service. On 
and after July 15, 2027, equipment leaks means emissions of hazardous 
air pollutants from a connector, pump, compressor, agitator, pressure 
relief device, sampling connection system, open-ended valve or line, 
valve, or instrumentation system in organic hazardous air pollutant 
service.
    Heat Exchange System means any cooling tower system or once-through 
cooling water system (e.g., river or pond water). A heat exchange 
system can include more than one heat exchanger and can include an 
entire recirculating or once-through cooling system.
    In organic hazardous air pollutant or in organic HAP service means 
that a piece of equipment either contains or contacts a fluid (liquid 
or gas) that is at least 5 percent by weight of total organic HAP's as 
determined according to the provisions of Sec.  63.180(d). The 
provisions of Sec.  63.180(d) also specify how to determine that a 
piece of equipment is not in organic HAP service.
    Pressure relief device or valve means a valve, rupture disk, or 
similar device used only to release an unplanned, nonroutine discharge 
of gas from process equipment in order to avoid safety hazards or 
equipment damage. A pressure relief device discharge can result from an 
operator error, a malfunction such as a power failure or equipment 
failure, or other unexpected cause. Such devices include conventional, 
spring-actuated relief valves, balanced bellows relief valves, pilot-
operated relief valves, rupture disks, and breaking, buckling, or 
shearing pin devices. Devices that are actuated either by a pressure of 
less than or equal to 2.5 pounds per square inch gauge or by a vacuum 
are not pressure relief devices.
* * * * *

0
155. Amend Sec.  63.523 by revising paragraph (a), and adding 
paragraphs (d) and (e) as follows:


Sec.  63.523  Standards for basic liquid resins manufacturers.

    (a) Owners or operators of existing affected BLR sources shall 
operate sources such that the rate of emissions of hazardous air 
pollutants from all process vents, storage tanks, and wastewater 
systems combined shall not exceed 130 pounds per 1 million pounds of 
BLR produced, and comply with the dioxin and furans emissions limit for 
process vents specified in paragraph (e) of this section.
* * * * *
    (d) For each existing, new, or reconstructed affected BLR source, 
beginning no later than the compliance dates specified in Sec.  
63.521(c), the owner or operator must comply with the requirements of 
Sec.  63.104 for heat exchange systems, with the exceptions noted in 
paragraphs (d)(1) through (8) of this section.
    (1) When the term ``chemical manufacturing process unit'' is used 
in Sec.  63.104, the term ``existing, new, or reconstructed affected 
BLR source'' shall apply for the purposes of this subpart.
    (2) When the phrase ``a chemical manufacturing process unit meeting 
the conditions of Sec.  63.100(b)(1) through (b)(3), except for 
chemical manufacturing process units meeting the condition specified in 
Sec.  63.100(c)'' is used in the first sentence of Sec.  63.104(a), the 
term ``an existing, new, or reconstructed affected BLR source'' shall 
apply for the purposes of this subpart. When the phrase ``a chemical 
manufacturing process unit meeting the conditions of Sec.  63.100(b)(1) 
through (b)(3),'' is used in the last sentence of Sec.  63.104(a), the 
term ``an existing, new, or reconstructed affected BLR source'' shall 
apply for purposes of this subpart.
    (3) When Sec.  63.104 refers to table 4 to subpart F of this part 
or table 9 of subpart G of this part, the owner or operator is required 
to consider all hazardous air pollutants.
    (4) When Sec.  63.104(c)(3) specifies the monitoring plan retention 
requirements, and when Sec.  6 3.104(f)(1) refers to the record 
retention requirements in Sec.  63.103(c)(1) of subpart F of this part, 
the requirements in Sec.  63.527(d) shall apply, for the purposes of 
this subpart.
    (5) When Sec.  63.104(f)(2) requires information to be reported in 
the Periodic Reports required by Sec.  63.152(c), the owner or operator 
shall instead report the information specified in Sec.  63.104(f)(2) in 
the Periodic Reports required by Sec.  63.528(a), for the purposes of 
this subpart.
    (6) The compliance date for heat exchange systems subject to the 
provisions of this section is specified in Sec.  63.521(c).
    (7) Substitute ``Beginning no later than the compliance dates 
specified in Sec.  63.521(c),'' for each occurrence of ``Beginning no 
later than the compliance dates specified in Sec.  63.100(k)(10),''.
    (8) Sec.  63.104(k) does not apply. Instead for each existing, new, 
or reconstructed affected BLR source, beginning no later than the 
compliance dates specified in Sec.  63.521(c), owners and operators 
must not inject water into or dispose of water through any heat 
exchange system in an affected source if the water is considered 
wastewater as defined in Sec.  63.522.
    (e) For each existing, new, or reconstructed affected BLR source, 
beginning no later than the compliance dates specified in Sec.  
63.521(c), the owner or operator of a process vent that contains 
chlorine, hydrogen chloride, or any other chlorinated compound must 
reduce emissions of dioxins and furans (toxic equivalency basis) to a 
concentration of 0.054 nanograms per standard cubic meter on a dry 
basis corrected to 3 percent oxygen.

0
156. Amend Sec.  63.524 by revising paragraph (a) introductory text, 
adding paragraph (a)(3), revising paragraph (b) introductory text, and 
adding paragraphs (b)(3) and (c) as follows:


Sec.  63.524  Standards for wet strength resins manufacturers.

    (a) In addition to the requirements specified in paragraph (c) of 
this section, and except as specified in paragraph (a)(3) of this 
section, owners or operators of existing affected WSR sources shall 
either:
* * * * *
    (3) For each existing affected WSR source, beginning no later than 
the compliance dates specified in Sec.  63.521(c), the owner or 
operator shall comply with both paragraphs (a)(1) and (a)(2) of this 
section and must reduce emissions of dioxins and furans (toxic 
equivalency basis) from each process vent that contains chlorine, 
hydrogen chloride, or any other chlorinated compound to a concentration 
of 0.054 nanograms per standard cubic meter on a dry basis corrected to 
3 percent oxygen.
    (b) In addition to the requirements specified in paragraph (c) of 
this section, and except as specified in paragraph (b)(3) of this 
section, owners

[[Page 43270]]

or operators of new or reconstructed affected WSR sources shall either:
* * * * *
    (3) For each new or reconstructed affected WSR source, beginning no 
later than the compliance dates specified in Sec.  63.521(c), the owner 
or operator shall comply with both paragraphs (b)(1) and (2) of this 
section and must reduce emissions of dioxins and furans (toxic 
equivalency basis) from each process vent that contains chlorine, 
hydrogen chloride, or any other chlorinated compound to a concentration 
of 0.054 nanograms per standard cubic meter on a dry basis corrected to 
3 percent oxygen.
    (c) For each existing, new, or reconstructed affected WSR source, 
beginning no later than the compliance dates specified in Sec.  
63.521(c), the owner or operator shall comply with the requirements of 
Sec.  63.104 for heat exchange systems, with the exceptions noted in 
paragraphs (d)(1) through (8) of this section.
    (1) When the term ``chemical manufacturing process unit'' is used 
in Sec.  63.104, the term ``existing, new, or reconstructed affected 
WSR source'' shall apply for the purposes of this subpart.
    (2) When the phrase ``a chemical manufacturing process unit meeting 
the conditions of Sec.  63.100(b)(1) through (b)(3) of this subpart, 
except for chemical manufacturing process units meeting the condition 
specified in Sec.  63.100(c) of this subpart'' is used in the first 
sentence of Sec.  63.104(a), the term ``an existing, new, or 
reconstructed affected WSR source'' shall apply for the purposes of 
this subpart. When the phrase ``a chemical manufacturing process unit 
meeting the conditions of Sec.  63.100(b)(1) through (b)(3),'' is used 
in the last sentence of Sec.  63.104(a), the term ``an existing, new, 
or reconstructed affected WSR source'' shall apply for purposes of this 
subpart.
    (3) When Sec.  63.104 refers to table 4 of subpart F of this part 
or Table 9 of subpart G of this part, the owner or operator is required 
to consider all hazardous air pollutants.
    (4) When Sec.  63.104(c)(3) specifies the monitoring plan retention 
requirements, and when Sec.  63.104(f)(1) refers to the record 
retention requirements in Sec.  63.103(c)(1), the requirements in Sec.  
63.527(d) shall apply, for the purposes of this subpart.
    (5) When Sec.  63.104(f)(2) requires information to be reported in 
the Periodic Reports required by Sec.  63.152(c), the owner or operator 
shall instead report the information specified in Sec.  63.104(f)(2) in 
the Periodic Reports required by Sec.  63.528(a), for the purposes of 
this subpart.
    (6) The compliance date for heat exchange systems subject to the 
provisions of this section is specified in Sec.  63.521(c).
    (7) Substitute ``Beginning no later than the compliance dates 
specified in Sec.  63.521(c),'' for each occurrence of ``Beginning no 
later than the compliance dates specified in Sec.  63.100(k)(10),
    (8) Sec.  63.104(k) of subpart F of this part does not apply. 
Instead for each existing, new, or reconstructed affected WSR source, 
beginning no later than the compliance dates specified in Sec.  
63.521(c), owners and operators must not inject water into (or dispose 
of water through) any heat exchange system in an affected source if the 
water is considered wastewater as defined in Sec.  63.522.

0
157. Amend Sec.  63.525 by:
0
a. Revising paragraphs (a) and (b)(1);
0
b. Adding paragraph (d)(3);
0
c. Revising paragraphs (e) introductory text and (e)(2)(iii);
0
d. Adding paragraph (e)(3);
0
e. Revising paragraphs (f), (g), (h) introductory text, and (i); and
0
f. Adding paragraphs (j) through (m) as follows:


Sec.  63.525  Compliance and performance testing.

    (a) The owner or operator of any existing affected BLR source 
shall, in order to demonstrate compliance with the applicable emission 
limits, determine the emission rate from all process vent, storage 
tank, and wastewater system emission points using the methods described 
below. Except as specified in paragraph (l) of this section, compliance 
tests shall be performed under normal operating conditions. Beginning 
no later than the compliance dates specified in Sec.  63.521(c), 
conduct subsequent performance tests no later than 60 calendar months 
after the previous performance test.
    (1) Except as specified in paragraph (m) of this section, the owner 
or operator shall use the EPA test methods from 40 CFR part 60, listed 
in paragraphs (a)(1) (i) through (iii) of this section, to determine 
emissions from process vents. Testing of process vents on equipment 
operating as part of a continuous process will consist of conducting 
three 1-hour runs. Gas stream volumetric flow rates shall be measured 
every 15 minutes during each 1-hour run. Organic HAP or TOC 
concentration shall be determined from samples collected in an 
integrated sample over the duration of each 1-hour test run, or from 
grab samples collected simultaneously with the flow rate measurements 
(every 15 minutes). If an integrated sample is collected for laboratory 
analysis, the sampling rate shall be adjusted proportionally to reflect 
variations in flow rate. If the flow of gaseous emissions is 
intermittent, determination of emissions from process vents shall be 
performed according to the methods specified in paragraph (e) of this 
section. For process vents with continuous gas streams, the emission 
rate used to determine compliance shall be the average emission rate of 
the 3 test runs. For process vents with intermittent emission streams, 
the calculated emission rate or the emission rate from a single test 
run may be used to determine compliance.
    (i) Method 1 or 1A of appendix A-1 to 40 CFR part 60 as 
appropriate, shall be used for selection of the sampling sites if the 
flow measuring device is a pitot tube. A traverse shall be conducted 
before and after each 1-hour sampling period. No traverse is necessary 
when using Method 2A or 2D of appendix A-2 to 40 CFR part 60 to 
determine flow rate.
    (ii) Method 2, 2A, 2C or 2D of appendix A-1 to part 60 of this 
chapter, as appropriate, shall be used for the determination of gas 
stream volumetric flow rate. If Method 2 or 2C is used, the velocity 
measurements shall be made at a single point, in conjunction with the 
traverse, to establish an average velocity across the stack.
    (iii) Method 25A and/or Methods 18 and 25A of appendices A-6 and A-
7 to 40 CFR part 60, as appropriate, must be used to determine the 
concentration of HAP in the streams. ASTM D6420-18 (incorporated by 
reference, see Sec.  63.14) may also be used in lieu of Method 18, if 
the target compounds are all known and are all listed in Section 1.1 of 
ASTM D6420-18 as measurable; ASTM D6420-18 must not be used for methane 
and ethane; and ASTM D6420-18 may not be used as a total VOC method.
    (iv) Initial determination of de minimis status for process vents 
may be made by engineering assessment, as specified in Sec.  
63.526(a)(1)(iv).
    (2) Emissions from wastewater treatment systems shall be determined 
in accordance with the methods described in 40 CFR part 63, appendix C.
    (3) Emissions from storage tanks shall be calculated in accordance 
with the methods specified in Sec.  63.150(g)(3).
    (b) * * *
    (1) The production-based emission rate for process vents shall be 
calculated by dividing the average emission rate by the average 
production rate.
* * * * *

[[Page 43271]]

    (d) * * *
    (3) To demonstrate compliance with the process vent dioxins and 
furans emission limit, the owner or operator must use the procedures of 
paragraph (m) of this section.
    (e) The owner or operator of any existing, new, or reconstructed 
WSR source that is subject to the emission limit for process vents, 
storage tanks, and wastewater systems shall demonstrate compliance by 
determining emissions for all process vent, storage tank, and 
wastewater systems emission points using the methods described in this 
section. The owner or operator of any existing, new, or reconstructed 
WSR source that is subject to the process vent dioxins and furans 
emission limit must demonstrate compliance by following the procedures 
in paragraph (e)(3) of this section. Beginning no later than the 
compliance dates specified in Sec.  63.521(c), conduct subsequent 
performance tests no later than 60 calendar months after the previous 
performance test.
* * * * *
    (2) * * *
* * * * *
    (iii) Method 25A and/or Methods 18 and 25A of appendices A-6 and A-
7 to 40 CFR part 60, as appropriate, must be used to determine the 
concentration of HAP in the streams. ASTM D6420-18 (incorporated by 
reference, see Sec.  63.14) may also be used in lieu of Method 18, if 
the target compounds are all known and are all listed in Section 1.1 of 
ASTM D6420-18 as measurable; ASTM D6420-18 must not be used for methane 
and ethane; and ASTM D6420-18 may not be used as a total VOC method.
* * * * *
    (3) To demonstrate compliance with the process vent dioxins and 
furans emission limit, the owner or operator must use the procedures of 
paragraph (m) of this section. Testing shall be performed for each unit 
operation.
    (f) The owner or operator of any affected WSR source that is 
subject to the emissions limit for process vents, storage tanks, and 
wastewater systems shall calculate emissions from storage tanks in 
accordance with the methods specified in Sec.  63.150(g)(3).
    (g) The owner or operator of any affected WSR source that is 
subject to the emission limit for process vents, storage tanks, and 
wastewater systems shall calculate emissions from wastewater treatment 
systems (if applicable) in accordance with the methods described in 40 
CFR part 63, appendix C.
    (h) The owner or operator of any affected WSR source that is 
subject to the emission limit for process vents, storage tanks, and 
wastewater systems shall calculate the average amount of WSR product 
manufactured per batch, using data from performance tests or from 
emission calculations, as applicable, to determine the average WSR 
production per-batch production data for an annual period representing 
normal operating conditions.
* * * * *
    (i) The owner or operator of any affected BLR source or any 
affected WSR source that is subject to the requirements of subpart H of 
this part must demonstrate the ability of its specific program to meet 
the compliance requirements therein to achieve initial compliance.
    (j) For each existing, new, or reconstructed affected BLR and WSR 
source, beginning no later than the compliance dates specified in Sec.  
63.521(c), owners and operators of sources as defined in Sec.  63.520 
shall comply with the requirements of this subpart at all times, except 
during periods of nonoperation of the source (or specific portion 
thereof) resulting in cessation of the emissions to which this subpart 
applies.
    (k) For each existing, new, or reconstructed affected BLR and WSR 
source, beginning no later than the compliance dates specified in Sec.  
63.521(c), at all times, owners and operators must operate and maintain 
any source, including associated air pollution control equipment and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions. The general duty 
to minimize emissions does not require owners and operators to make any 
further efforts to reduce emissions if levels required by the 
applicable standard have been achieved. Determination of whether a 
source is operating in compliance with operation and maintenance 
requirements will be based on information available to the 
Administrator which may include, but is not limited to, monitoring 
results, review of operation and maintenance procedures, review of 
operation and maintenance records, and inspection of the source.
    (l) For each existing, new, or reconstructed affected BLR and WSR 
source, beginning no later than the compliance dates specified in Sec.  
63.521(c), the owner or operator may not conduct performance tests 
during periods of malfunction. Owners and operators must record the 
process information that is necessary to document operating conditions 
during the test and include in such record an explanation to support 
that such conditions represent normal operation. Upon request, owners 
and operators must make available to the Administrator such records as 
may be necessary to determine the conditions of performance tests.
    (m) Except as specified in paragraph (m)(7) of this section, to 
demonstrate compliance with the process vent dioxins and furans 
emission limit, the owner or operator must conduct a performance test 
using the procedures in paragraphs (m)(1) through (m)(6) of this 
section. Conduct subsequent performance tests no later than 60 calendar 
months after the previous performance test.
    (1) The performance test must consist of three test runs. Collect 
at least 3 dry standard cubic meters of gas per test run.
    (2) Use Method 1 or 1A of 40 CFR part 60, appendix A-1 to select 
the sampling sites at the sampling location. The sampling location must 
be at the outlet of the final control device.
    (3) Determine the gas volumetric flowrate using Method 2, 2A, 2C, 
or 2D of 40 CFR part 60, appendix A-2.
    (4) Use Method 4 of 40 CFR part 60, appendix A-3 to convert the 
volumetric flowrate to a dry basis.
    (5) Measure the concentration of each tetra- through octa-
chlorinated dioxin and furan congener emitted using Method 23 at 40 CFR 
part 60, appendix A-7.
    (i) For each dioxin and furan congener, multiply the congener 
concentration by its corresponding toxic equivalency factor specified 
in table 2 to this subpart. For determination of toxic equivalency, 
zero may be used for congeners with a concentration less than the 
estimated detection limit (EDL). For congeners with estimated maximum 
pollutant concentration (EMPC) results, if the value is less than the 
EDL, zero may be used. Otherwise, the EMPC value must be used in the 
calculation of toxic equivalency.
    (ii) Sum the products calculated in accordance with paragraph 
(m)(5)(i) of this section to obtain the total concentration of dioxins 
and furans emitted in terms of toxic equivalency.
    (6) The concentration of dioxins and furans shall be corrected to 3 
percent oxygen. Use Method 3A of 40 CFR part 60, appendix A to 
determine the oxygen concentration (%O2d). Method 3A of 40 
CFR part 60, appendix A must be run concurrently with Method 23 of 40 
CFR part 60, appendix A-7. The concentration corrected to 3 percent 
oxygen (Cc) shall be computed using the following equation:

[[Page 43272]]

[GRAPHIC] [TIFF OMITTED] TR16MY24.067

Where:

Cc = Concentration of dioxins and furans corrected to 3 
percent oxygen, dry basis, nanograms per standard cubic meter.
Cm = Concentration of dioxins and furans, dry basis, 
nanograms per standard cubic meter.
%O2d = Concentration of oxygen, dry basis, percent by 
volume.

    (7) An owner or operator is not required to conduct a performance 
test when either a boiler or process heater burning hazardous waste, or 
hazardous waste incinerator, is used for which the owner or operator:
    (A) Has been issued a final permit under part 270 of this chapter 
and complies with the requirements of 40 CFR part 266, subpart H;
    (B) Has certified compliance with the interim status requirements 
of part 266, subpart H, of this chapter;
    (C) Meets the requirement specified in paragraph (g)(7)(i)(E) of 
this section, and has submitted a Notification of Compliance under 
Sec.  63.1207(j) and complies with the requirements of subpart EEE of 
this part; or
    (D) Meets the requirement specified in paragraph (g)(7)(i)(E) of 
this section, complies with subpart EEE of this part, and will submit a 
Notification of Compliance under Sec.  63.1207(j) by the date the owner 
or operator would have been required to submit the initial performance 
test report for this subpart.
    (E) The owner and operator may not waive performance testing 
pursuant to Sec.  63.1207(d)(4) and each performance test required by 
Sec.  63.1207(d) must show compliance with the dioxins and furans 
emission limit specified in Sec.  63.523(e) and Sec.  63.524(a)(3) and 
(b)(3), as applicable.

0
158. Amend Sec.  63.526 by:
0
 a. Revising paragraphs (a) introductory text, (a)(2), (3) and (4);
0
b. Adding paragraph (a)(7);
0
c. Revising paragraphs (b) introductory text, (b)(1)(i), (b)(2), (3), 
and (4);
0
d. Adding paragraph (b)(7); and
0
e, Revising paragraphs (c) and (d).
    The additions and revisions read as follows:


Sec.  63.526  Monitoring requirements.

    (a) The owner or operator of any existing, new, or reconstructed 
affected BLR source shall provide evidence of continued compliance with 
the standard. During each compliance demonstration, maximum or minimum 
operating parameters, as appropriate, shall be established for 
processes and control devices that will indicate the source is in 
compliance. If the operating parameter to be established is a maximum, 
the value of the parameter shall be the average of the maximum values 
from each of the three test runs. If the operating parameter to be 
established is a minimum, the value of the parameter shall be the 
average of the minimum values from each of the three test runs. 
Parameter values for process vents with intermittent emission streams 
shall be determined as specified in paragraph (b)(1) of this section. 
The owner or operator shall operate processes and control devices 
within these parameters to ensure continued compliance with the 
standard. A de minimis level is specified in paragraph (a)(1) of this 
section. Monitoring parameters are specified for various process vent 
control scenarios in paragraphs (a) (2) through (7) of this section.
* * * * *
    (2) For affected sources using water scrubbers, the owner or 
operator shall establish a minimum scrubber water flow rate as a site-
specific operating parameter which must be measured and recorded every 
15 minutes. The affected source will be considered to be out of 
compliance if the scrubber water flow rate, averaged over any 
continuous 24-hour period, is below the minimum value established 
during the most recent compliance demonstration.
    (3) For affected sources using condensers, the owner or operator 
shall establish the maximum condenser outlet gas temperature as a site-
specific operating parameter which must be measured and recorded every 
15 minutes. The affected source will be considered to be out of 
compliance if the condenser outlet gas temperature, averaged over any 
continuous 24-hour period, is greater than the maximum value 
established during the most recent compliance demonstration.
    (4) For affected sources using carbon adsorbers or having 
uncontrolled process vents, the owner or operator shall establish a 
maximum outlet HAP concentration as the site-specific operating 
parameter which must be measured and recorded every 15 minutes. The 
affected source will be considered to be out of compliance if the 
outlet HAP concentration, averaged over any continuous 24-hour period, 
is greater than the maximum value established during the most recent 
compliance demonstration.
* * * * *
    (7) For affected sources using sorbent injection, the owner or 
operator shall establish both a minimum sorbent injection rate and 
minimum carrier gas flow rate flow rate as site-specific operating 
parameters which must be measured and recorded every 15 minutes. The 
affected source will be considered to be out of compliance if the 
sorbent injection rate or the carrier gas flow rate flow rate, averaged 
over any continuous 24-hour period, is below the minimum values 
established during the most recent compliance demonstration.
    (b) The owner or operator of any existing, new, or reconstructed 
affected WSR source that is subject to the emission limit for process 
vents, storage tanks, and wastewater systems and/or is subject to the 
dioxins and furans emission limit for process vents shall provide 
evidence of continued compliance with the standard. As part of each 
compliance demonstrations for batch process vents, test data or 
compliance calculations shall be used to establish a maximum or minimum 
level of a relevant operating parameter for each unit operation. The 
parameter value for each unit operation shall represent the worst case 
value of the operating parameter from all episodes in the unit 
operation. The owner or operator shall operate processes and control 
devices within these parameters to ensure continued compliance with the 
standard.
    (1) * * *
    (i) If testing is used to demonstrate compliance, the appropriate 
parameter shall be monitored during all batch emission episodes in the 
unit operation.
* * * * *
    (2) Affected sources with condensers on process vents shall 
establish the maximum condenser outlet gas temperature as a site-
specific operating parameter, which must be measured every 15 minutes, 
or at least once for batch emission episodes less than 15 minutes in 
duration. The affected source will be considered to be out of 
compliance if the maximum condenser outlet gas temperature, averaged 
over the duration of the batch emission episode or unit operation, is 
greater than the value established during the most recent compliance 
demonstration.

[[Page 43273]]

    (3) For affected sources using water scrubbers, the owner or 
operator shall establish a minimum scrubber water flow rate as a site-
specific operating parameter which must be measured and recorded every 
15 minutes, or at least once for batch emission episodes less than 15 
minutes in duration. The affected source will be considered to be out 
of compliance if the scrubber water flow rate, averaged over the 
duration of the batch emission episode or unit operation, is below the 
minimum flow rate established during the most recent compliance 
demonstration.
    (4) For affected sources using carbon adsorbers or having 
uncontrolled process vents, the owner or operator shall establish a 
maximum outlet HAP concentration as the site-specific operating 
parameter which must be measured and recorded every 15 minutes, or at 
least once for batch emission episodes of duration shorter than 15 
minutes. The affected source will be considered to be out of compliance 
if the outlet HAP concentration, averaged over the duration of the 
batch emission episode or unit operation, is greater than the value 
established during the most recent compliance demonstration.
* * * * *
    (7) For affected sources using sorbent injection, the owner or 
operator shall establish both a minimum sorbent injection rate and 
minimum carrier gas flow rate flow rate as site-specific operating 
parameters which must be measured and recorded every 15 minutes. The 
affected source will be considered to be out of compliance if the 
sorbent injection rate or the carrier gas flow rate flow rate, averaged 
over any continuous 24-hour period, is below the minimum values 
established during the most recent compliance demonstration.
    (c) Periods of time when monitoring measurements exceed the 
parameter values do not constitute a violation if they occur during a 
startup, shutdown, or malfunction, and the facility is operated in 
accordance with Sec.  63.6(e)(1). For each existing, new, or 
reconstructed affected BLR and WSR source, on and after July 15, 2027, 
this paragraph no longer applies.
    (d) The owner or operator of any affected WSR source that is 
subject to the requirements of subpart H of this part shall meet the 
monitoring requirements of subpart H of this part.

0
159. Amend Sec.  63.527 by revising paragraphs (b), (c) introductory 
text and (d), and adding paragraphs (f) and (g) as follows:


Sec.  63.527  Recordkeeping requirements.

* * * * *
    (b) The owner or operator of any affected WSR source subject to the 
emission limit for process vents, storage tanks, and wastewater systems 
and/or subject to the dioxins and furans emission limit for process 
vents shall keep records of values of equipment operating parameters 
specified to be monitored under Sec.  63.526(b) or specified by the 
Administrator. The records that shall be kept are the average values of 
operating parameters, determined for the duration of each unit 
operation. Records shall be kept in accordance with the requirements of 
applicable paragraphs of Sec.  63.10, as specified in the General 
Provisions applicability table in this subpart. The owner or operator 
shall keep records up-to-date and readily accessible. In the event of 
an excursion, the owner or operator must keep records of each 15-minute 
reading for the entire unit operation in which the excursion occurred.
    (c) The owner or operator of any affected BLR source, as well the 
owner or operator of any affected WSR source that is subject to the 
emission limit for process vents, storage tanks, and wastewater 
systems, who demonstrates that certain process vents are below the de 
minimis cutoff for continuous monitoring specified in Sec.  
63.526(a)(1)(i), shall maintain up-to-date, readily accessible records 
of the following information to document that a HAP emission rate of 
less than one pound per year is maintained:
* * * * *
    (d) The owner or operator of any affected BLR source, as well as 
the owner or operator of any affected WSR source subject to the leak 
detection and repair program specified in subpart H of this part, shall 
implement the recordkeeping requirements outlined therein. All records 
shall be retained for a period of 5 years, in accordance with the 
requirements of 40 CFR 63.10(b)(1).
* * * * *
    (f) For each existing, new, or reconstructed affected BLR and WSR 
source, beginning no later than the compliance dates specified in Sec.  
63.521(c), the owner or operator of any affected BLR source, as well 
the owner or operator of any affected WSR source subject to the 
emission limit for process vents, storage tanks, and wastewater 
systems, must keep the records specified in paragraphs (f)(1) through 
(3) of this section each pressure relief device, as defined in Sec.  
63.522.
    (1) The start and end time and date of each pressure release to the 
atmosphere.
    (2) An estimate of the mass quantity in pounds of each organic HAP 
released.
    (3) Records of any data, assumptions, and calculations used to 
estimate of the mass quantity of each organic HAP released during the 
event.
    (g) For each existing, new, or reconstructed affected BLR and WSR 
source, beginning no later than the compliance dates specified in Sec.  
63.521(c), the owner or operator of any affected BLR source, as well 
the owner or operator of any affected WSR source subject to the 
emission limit for process vents, storage tanks, and wastewater 
systems, must keep the records specified in paragraphs (g)(1) through 
(3) of this section for each maintenance vent release. A process vent 
is considered a maintenance vent if the process vent is only used as a 
result of startup, shutdown, maintenance, or inspection of equipment 
where equipment is emptied, depressurized, degassed, or placed into 
service.
    (1) Identification of the maintenance vent and the equipment served 
by the maintenance vent.
    (2) The date and time the maintenance vent was opened to the 
atmosphere.
    (3) An estimate of the mass in pounds of organic HAP released 
during the entire atmospheric venting event.

0
160. Revise and republish Sec.  63.528 to read as follows:


Sec.  63.528  Reporting requirements.

    (a) The owner or operator of any affected BLR source, as well as 
the owner or operator of any affected WSR source that is subject to the 
emission limit for process vents, storage tanks, and wastewater systems 
and/or is subject to the dioxins and furans emission limit for process 
vents, shall comply with the reporting requirements of applicable 
paragraphs of Sec.  63.10, as specified in the General Provisions 
applicability table in this subpart. The owner or operator shall also 
submit to the Administrator, as part of the quarterly excess emissions 
and continuous monitoring system performance report and summary report 
required by Sec.  63.10(e)(3), the following recorded information. On 
and after July 15, 2027 or once the reporting template for this subpart 
has been available on the CEDRI website for 1 year, whichever date is 
later, owners and operators must submit all subsequent reports 
following the procedure specified in Sec.  63.9(k), except any medium 
submitted through mail must be sent to the attention of the Polymers 
and Resins Sector Lead. Owners and operators must use the appropriate 
electronic report template on the CEDRI website (https://

[[Page 43274]]

www.epa.gov/electronic-reporting-air-emissions/cedri) for this subpart. 
The date report templates become available will be listed on the CEDRI 
website. Unless the Administrator or delegated state agency or other 
authority has approved a different schedule for submission of reports 
under Sec.  63.9(i) and Sec.  63.10(a), the report must be submitted by 
the deadline specified in this subpart, regardless of the method in 
which the report is submitted. If a report is submitted via CEDRI, the 
certifier's electronic signature during the submission process replaces 
the requirements in Sec.  63.10(e)(3)(v), Sec.  63.10(e)(3)(vi)(L), and 
Sec.  63.10(e)(3)(vi)(M) to submit the date of the report and the name, 
title, and signature of the responsible official who is certifying the 
accuracy of the report.
    (1) Reports of monitoring data, including 15-minute monitoring 
values as well as daily average values or per-unit operation average 
values, as applicable, of monitored parameters for all operating days 
or unit operations when the average values were outside the ranges 
established in the Notification of Compliance Status or operating 
permit, including reports specified in paragraph (a)(4) of this 
section.
    (2) Reports of the duration of periods when monitoring data is not 
collected for each excursion caused by insufficient monitoring data, 
including reports specified in paragraph (a)(4) of this section. An 
excursion means any of the three cases listed in paragraph (a)(2)(i) or 
(a)(2)(ii) of this section. For a control device where multiple 
parameters are monitored, if one or more of the parameters meets the 
excursion criteria in paragraph (a)(2)(i) or (a)(2)(ii) of this 
section, this is considered a single excursion for the control device. 
In the report, include the identification of the source, start date, 
start time, duration in hours, and monitored parameter(s) meeting the 
excursion criteria.
    (i) When the period of control device operation is 4 hours or 
greater in an operating day and monitoring data are insufficient to 
constitute a valid hour of data, as defined in paragraph (a)(2)(iii) of 
this section, for at least 75 percent of the operating hours.
    (ii) When the period of control device operation is less than 4 
hours in an operating day and more than one of the hours during the 
period of operation does not constitute a valid hour of data due to 
insufficient monitoring data.
    (iii) Monitoring data are insufficient to constitute a valid hour 
of data, as used in paragraphs (a)(2)(i) and (ii) of this section, if 
measured values are unavailable for any of the 15-minute periods within 
the hour.
    (3) Whenever a process change, as defined in Sec.  63.115(e), is 
made that causes the emission rate from a de minimis emission point to 
become a process vent with an emission rate of one pound per year or 
greater, the owner or operator shall submit a report within 180 
calendar days after the process change. The report may be submitted as 
part of the next summary report required under Sec.  63.10(e)(3). The 
report shall include:
    (i) A description of the process change; and
    (ii) The results of the recalculation of the emission rate.
    (4) For each existing, new, or reconstructed affected BLR and WSR 
source, beginning no later than the compliance dates specified in Sec.  
63.521(c), for each excursion that is not an excused excursion, the 
report must include a list of the affected sources or equipment, the 
monitored parameter, an estimate of the quantity in pounds of each 
regulated pollutant emitted over any emission limit, a description of 
the method used to estimate the emissions, the cause of the excursion 
(including unknown cause, if applicable), as applicable, and the 
corrective action taken. Include the start date, start time, and 
duration in hours of each excursion.
    (5) For pressure relief device subject to Sec.  63.527(f), report 
each pressure release to the atmosphere, including pressure relief 
device identification name or number, the start date, start time, and 
duration (in minutes) of the pressure release; and an estimate of the 
mass quantity in pounds of each organic HAP released.
    (6) For heat exchangers subject to Sec.  63.104 of subpart F of 
this part, the information specified in Sec.  63.104(f)(2) of subpart F 
of this part.
    (b) The owner or operator of any affected BLR source, as well as 
the owner or operator of any affected WSR source who is subject to the 
leak detection and repair program specified in subpart H of this part, 
shall implement the reporting requirements outlined therein. Copies of 
all reports shall be retained as records for a period of 5 years, in 
accordance with the requirements of 40 CFR 63.10(b)(1).
    (c) The owner or operator of any affected BLR source, as well as 
the owner or operator of any affected WSR source that is subject to the 
emission limit for process vents, storage tanks, and wastewater systems 
shall include records of all monitoring parameters in the Notification 
of Compliance Status and summary reports required by subpart A of this 
part.
    (d) Beginning no later than July 15, 2024, owners and operators 
must submit performance test reports in accordance with this paragraph. 
Unless otherwise specified in this subpart, within 60 days after the 
date of completing each performance test required by this subpart, 
owners and operators must submit the results of the performance test 
following the procedures specified in Sec.  63.9(k). Data collected 
using test methods supported by the EPA's Electronic Reporting Tool 
(ERT) as listed on the EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at 
the time of the test must be submitted in a file format generated using 
the EPA's ERT. Alternatively, owners and operators may submit an 
electronic file consistent with the extensible markup language (XML) 
schema listed on the EPA's ERT website. Data collected using test 
methods that are not supported by the EPA's ERT as listed on the EPA's 
ERT website at the time of the test must be included as an attachment 
in the ERT or alternate electronic file.

0
161. Amend Sec.  63.529 by revising paragraph (c) introductory text, 
and adding paragraph (c)(5) as follows:


Sec.  63.529  Implementation and enforcement.

* * * * *
    (c) The authorities that cannot be delegated to State, local, or 
Tribal agencies are as specified in paragraphs (c)(1) through (5) of 
this section.
* * * * *
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.

0
162. Amend table 1 to subpart W by:
0
a. Revising the header row;
0
b. Revising entry ``Sec.  63.6(e)(1)(i)'';
0
c. Adding entries ``Sec.  63.6(e)(1)(ii)'', ``Sec.  63.6(e)(1)(iii)'', 
``63.6(e)(2)'', and ``63.6(e)(3)';
0
d. Revising entry ``Sec.  63.6(g)'';
0
e. Adding entry ``Sec.  63.7(a)(4)''; and
0
f. Revising entries ``Sec.  63.7(e)(1)'', ``Sec.  63.7(g)(1)'', ``Sec.  
63.8(c)(1)(i)'', ``Sec.  63.8(c)(1)(iii)'', ``Sec.  63.9(k)'', ``Sec.  
63.10(d)(2)'', ``Sec.  63.10(d)(5)'' and ``Sec.  63.10(e)(3)''.
    The revisions and additions read as follows:

[[Page 43275]]



                                     Table 1 to Subpart W of Part 63--General Provisions Applicability to Subpart W
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Applies to subpart W
                                      ---------------------------------------------------------------------------------------
              Reference                                                                    WSR equipment leak standard, and             Comment
                                                 BLR                      WSR              BLR equipment leak  standard (40
                                                                                               CFR part 63, subpart H)
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                      * * * * * * *
Sec.   63.6(e)(1)(i).................                                       See Comment                                       Yes, before July 15, 2027.
                                                                                                                               No, beginning on and
                                                                                                                               after July 15, 2027. See
                                                                                                                               Sec.   63.525(k) for
                                                                                                                               general duty requirement.
Sec.   63.6(e)(1)(ii)................                                       See Comment                                       Yes, before July 15, 2027.
                                                                                                                               No, beginning on and
                                                                                                                               after July 15, 2027.
Sec.   63.6(e)(1)(iii)...............  Yes....................  Yes....................  Yes................................
63.6(e)(2)...........................  N/A....................  N/A....................  N/A................................  Reserved.
63.6(e)(3)...........................                                       See Comment                                       Yes, before July 15, 2027.
                                                                                                                               No, beginning on and
                                                                                                                               after July 15, 2027.
 
                                                                      * * * * * * *
Sec.   63.6(g).......................  Yes....................  Yes....................  Yes................................  Affected sources have the
                                                                                                                               opportunity to
                                                                                                                               demonstrate other
                                                                                                                               alternatives to the
                                                                                                                               Administrator.
 
                                                                      * * * * * * *
Sec.   63.7(a)(4)....................  Yes....................  Yes....................  Yes................................
 
                                                                      * * * * * * *
Sec.   63.7(e)(1)....................           Yes, before July 15, 2027. No, beginning on and after July 15, 2027.          See Sec.   63.525(l).
                                                                                                                               Subpart W also contains
                                                                                                                               test methods specific to
                                                                                                                               BLR and WSR sources.
 
                                                                      * * * * * * *
Sec.   63.7(g)(1)....................  Yes....................  Yes....................  No.................................  Subpart H specifies
                                                                                                                               performance test
                                                                                                                               reporting. Additionally,
                                                                                                                               this subpart specifies
                                                                                                                               how and when the
                                                                                                                               performance test results
                                                                                                                               are reported for BLR and
                                                                                                                               WSR.
Sec.   63.8(b)(3)....................  Yes....................  Yes....................  Yes................................
Sec.   63.8(c)(1)(i).................           Yes, before July 15, 2027. No, beginning on and after July 15, 2027.
 
                                                                      * * * * * * *
Sec.   63.8(c)(1)(iii)...............           Yes, before July 15, 2027. No, beginning on and after July 15, 2027.
 
                                                                      * * * * * * *
Sec.   63.9(k).......................  Yes....................  Yes....................  Yes................................
 
                                                                      * * * * * * *
Sec.   63.10(d)(2)...................  No.....................  No.....................  No.................................  This subpart and Subpart H
                                                                                                                               specify performance test
                                                                                                                               reporting requirements.
 
                                                                      * * * * * * *
Sec.   63.10(d)(5)...................           Yes, before July 15, 2027. No, beginning on and after July 15, 2027.
 
                                                                      * * * * * * *
Sec.   63.10(e)(3)...................  Yes....................  Yes....................  No.................................  Except that on and after
                                                                                                                               July 15, 2027, the
                                                                                                                               reports shall be
                                                                                                                               submitted according to
                                                                                                                               and in the format
                                                                                                                               required by Sec.
                                                                                                                               63.528(a).
 
                                                                      * * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------


0
163. Add table 2 to subpart W to read as follows:

       Table 2 to Subpart W of part 63--Toxic Equivalency Factors
------------------------------------------------------------------------
                                                     Toxic  equivalency
             Dioxin and Furan Congener                     factor
------------------------------------------------------------------------
1,2,3,7,8-pentachlorodibenzo-p-dioxin.............                     1
1,2,3,4,7,8-hexachlorodibenzo-p-dioxin............                   0.1
1,2,3,7,8,9-hexachlorodibenzo-p-dioxin............                   0.1
1,2,3,6,7,8-hexachlorodibenzo-p-dioxin............                   0.1

[[Page 43276]]

 
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin.........                  0.01
octachlorodibenzo-p-dioxin........................                0.0003
2,3,7,8-tetrachlorodibenzofuran...................                   0.1
2,3,4,7,8-pentachlorodibenzofuran.................                   0.3
1,2,3,7,8-pentachlorodibenzofuran.................                  0.03
1,2,3,4,7,8-hexachlorodibenzofuran................                   0.1
1,2,3,6,7,8-hexachlorodibenzofuran................                   0.1
1,2,3,7,8,9-hexachlorodibenzofuran................                   0.1
2,3,4,6,7,8-hexachlorodibenzofuran................                   0.1
1,2,3,4,6,7,8-heptachlorodibenzofuran.............                  0.01
1,2,3,4,7,8,9-heptachlorodibenzofuran.............                  0.01
Octachlorodibenzofuran............................                0.0003
------------------------------------------------------------------------

0
164. Add Method 327 to appendix A of part 63 to read as follows:

Method 327--Fugitive and Area Source Measurement of Selected Volatile 
Organic Hazardous Air Pollutants Using Specially Prepared Canisters

1.0 Scope and Application

    1.1 This method describes the sampling and analysis of emissions 
from fugitive and area sources collected using specially prepared 
canisters and analyzed using a gas chromatograph (GC) coupled with a 
low- or high-resolution mass spectrometer (MS) for the determination of 
the airborne concentration of selected volatile organic hazardous air 
pollutants (oHAPs) such as ethylene oxide or vinyl chloride.
    1.2 Applicability. The use of this method is strictly intended for 
determining airborne concentrations of selected speciated oHAPs to 
determine compliance with a fenceline emission standard and/or work 
practices when specified by the applicable regulation. This method 
includes data quality objectives (DQOs) specific to the measurement of 
airborne concentrations of speciated oHAPs and must not be used for 
other compliance purposes (i.e., measurements from ducted sources).
    1.3 The analytical approach for this method uses a GC coupled with 
a low- or high-resolution MS, which may consist of a linear quadrupole, 
ion trap, or time-of-flight (TOF) system. Speciated oHAPs are 
identified by a combination of the retention times (RTs) and the 
associated mass spectra by comparing observed fragmentation patterns to 
reference spectral patterns and relative ion abundances established 
during calibration. For the speciated oHAPs, the intensity of the 
observed quantitation ion in the unknown sample is compared with the 
system response to the same ion for known amounts of the compound.
    1.4 The sampling and analytical approach included in this method is 
based on previously published EPA guidance in Compendium Method TO-15A, 
which describes the sampling and analytical procedures for measuring 
volatile organic compounds (VOCs) in ambient air.

2.0 Summary of Method

    2.1 In this method, a whole air sample is collected through a 
particulate filter with a flow control device into an evacuated, 
specially prepared canister for a length of time specified by the 
applicable regulation, typically 24 hours. After the air sample is 
collected, the canister valve is closed, the canister pressure is 
measured, and the canister is transported to the laboratory for 
analysis. Upon receipt at the laboratory, the sample collection 
information is verified, the canister pressure is measured, and the 
canister is stored at ambient laboratory temperature until analysis. 
For analysis, a known volume of the sample is directed from the 
canister into a preconcentrator to collect speciated oHAPs from the 
sample aliquot and to allow the majority of bulk gases (e.g., nitrogen, 
oxygen, argon, and carbon dioxide) and water vapor to be vented.
    2.2 The laboratory, field laboratory, and field personnel must have 
experience with sampling trace-level oHAPs using specially prepared 
canisters and with operating preconcentrator/GC/multidetector 
instrumentation (e.g., MS) for trace-level analysis.
    2.3 This method is performance-based and includes a description of 
the equipment, instruments, operations, and acceptance and performance 
criteria. EPA developed these criteria to ensure the collection of 
high-quality data. Laboratories must develop their own standard 
operating procedure (SOP) documents describing the equipment, equipment 
management, targeted compounds, procedures, and quality assurance (QA) 
activities specific to that laboratory, instrumentation, and 
potentially specific for the targeted analyte.
    2.4 The key steps of this method required for the collection of 
each sample include stringent leak testing under stop flow, using 
certified and clean canisters, using certified sampling devices, 
collecting accurate field data, and collecting field blanks and 
duplicates. The key steps of this method required for sample analysis 
include the analysis of blanks, use of high-quality reference 
standards, and initial and ongoing calibration checks of the 
instruments used.

3.0 Definitions

    3.1 Absolute pressure means the pressure measured with reference to 
absolute zero pressure, usually expressed in units of kilopascal (kPa) 
absolute or pounds per square inch absolute (psia).
    3.2 Analytical batch means the batch of samples analyzed over a 24-
hour period beginning with the daily instrument tune performance check.
    3.2 Collocated precision means the precision determined from the 
analyzed concentrations of samples collected simultaneously from the 
same air mass using two discrete canisters and collected through two 
separate sampling devices with separate inlets. This determines the 
precision of the method including the sampling and analysis processes. 
Collocated precision is determined by calculating the absolute relative 
percent difference (RPD) for the collocated measurements (the absolute 
value of the difference between the two collocated sample results 
divided by their average value and expressed as a percentage).
    3.3 Continuing calibration verification sample (CCV) means single

[[Page 43277]]

level calibration samples run conducted periodically to confirm that 
the analytical system continues to generate sample results within 
acceptable agreement to the current calibration curve.
    3.4 Cryogen means a refrigerant used to obtain sub-ambient 
temperatures in the preconcentrator and/or the GC oven. Typical 
cryogens are liquid nitrogen (boiling point [BP] -195.8 [deg]C), liquid 
argon (BP -185.7 [deg]C), and liquid carbon dioxide (BP -79.5 [deg]C).
    3.5 Deionized water means ASTM Type I water or equivalent.
    3.6 Diluent gas means hydrocarbon-free (HCF) synthetic ``zero'' 
air.
    3.7 Dynamic dilution means a technique for preparing calibration 
mixtures in which standard gas(es) from pressurized cylinders are 
continuously blended with a diluent gas (such as humidified HCF zero 
air) in a mixing chamber or manifold so that a flowing stream of 
calibration mixture is created.
    3.8 Gauge pressure means the pressure measured with reference to 
the surrounding atmospheric pressure, usually expressed in units of kPa 
or inches of mercury (Hg). Gauge pressure is zero-referenced against 
ambient air pressure; zero is equal to the local atmospheric 
(barometric) pressure, which is nominally 101.3 kPa (29.92 in. Hg or 
14.7 psia) at sea level.
    3.9 Mass spectrometer means an instrument that ionizes molecules 
and atoms (typically into electrically charged fragments), separates 
these ions according to their mass-to-charge ratio (m/z or m/e), and 
responds to the impact of the ions based on their population. MS 
systems suitable for this method include quadrupole, ion trap, and TOF 
detectors. Quadrupole and ion trap MS operating modes (i.e., full-scan, 
selected ion monitoring [SIM], and selected ion storage [SIS] modes) 
can be selected to optimize the ion mass collection range.
    3.10 Mechanical Flow Controlling Device (MFCD) means a device that 
is used to ensure constant flow to an evacuated canister to near 
ambient pressure. MCFD are designed to maintain a constant pressure 
drop (and thus a constant flow rate) across a restrictive orifice by 
allowing a constant leak rate of sample into the canister as the 
canister vacuum decreases to near ambient pressure without power.
    3.11 Nominal concentration means a requested, target, or named 
concentration that approximates the true, reference, or certified 
concentration. For example, a nominal 200 parts per trillion by volume 
(pptv) standard may have an actual certified concentration of 206 pptv.
    3.12 Preconcentrator means a device used to concentrate the target 
compound(s) while the bulk gases are effectively removed. The target 
compound(s) are then desorbed and injected into a GC-MS system.
    3.13 Quantitative accuracy means the degree of measurement accuracy 
required to measure the concentration of an identified compound, within 
a given tolerance of uncertainty, with an analytical system.
    3.14 Replicate precision means the precision determined from 
repeated analysis of a gas sample from one canister, which may be 
evaluated by calculating the absolute RPD for pairwise measurements (N 
= 2) or by determining the relative standard deviation (RSD) for 
replicate measurements where N >= 3. Replicate analyses are used to 
determine precision of the analysis processes and do not provide 
information on sampling precision.
    3.15 Second Source Calibration Verification (SSCV) Standard means a 
humidified calibration standard prepared from a calibration stock gas 
procured from a separate supplier. An SSCV can only be prepared with a 
calibration stock from the same supplier if it is unavailable from 
another supplier and is prepared from a different lot of source 
material as the primary calibration stock.
    3.16 Static dilution means a technique for preparing calibration 
mixtures in which standard and diluent gases are added to a fixed-
volume vessel or chamber at a known ratio. Standard and diluent gas 
amounts may be measured gravimetrically, by volume, and/or by pressure 
differential from pressurized cylinders or as neat materials and 
blended with a known amount of diluent gas (such as humidified zero 
air) in a mixing chamber or manifold.
    3.17 Target concentration means desired, estimated, or approximate 
concentration (see ``nominal concentration'' above).
    3.18 Theoretical concentration means a reference concentration 
derived by applying measurements performed with calibrated instruments 
with known tolerances to a certified reference standard concentration 
value. Measurements of the target compound(s) concentrations are to be 
determined using a calibration that is developed based on theoretical 
concentrations.
    3.19 Time-of-flight (TOF) mass spectrometry means a MS method that 
determines the ion's mass-to-charge ratio by measuring the time the ion 
takes to reach the detector.
    3.20 Wetted surfaces mean the surfaces of the flow path, canister, 
valving, pumps, etc., that contact the gas undergoing collection, 
mixing, transfer, or analysis.

4.0 Interferences

    4.1 Sample Collection. There are potential physical interferents 
which could impact the ability to properly time-integrate the sampling, 
such as leaks of the sampling system or introduction of foreign 
material (e.g., particulate matter [PM], insect nests, spider webs). 
These interferences are mitigated by closely following the sampling 
protocols included in this method (e.g., leak check procedures and 
sampling system requirements).
    4.2 Canister Sampling Media Interferences. Each canister will have 
its own specific performance characteristics and appropriate cleaning, 
sampling, and handling procedures are required for attainment of 
acceptable initial and ongoing method performance. Failure to adhere to 
the cleaning and certification requirements included in this method may 
lead to the following interference issues:
    (1) Incomplete deactivation of canister interior surfaces (e.g., 
canister welds) may result in active sites for adsorption or surfaces 
that facilitate the decomposition of labile VOCs to form other VOCs 
within the canister. Other potential sources of active sites include 
canister valves, valve stems, and ferrules. Damage to the canister 
interior that exposes untreated surfaces may also result in active 
sites.
    (2) Entrained PM deposited in the canister sampling pathway can 
adsorb VOCs making them unavailable in the canister gas phase which 
interferes with collected samples. Such trapped VOCs can potentially 
desorb later and result in the inability to achieve canister 
cleanliness performance specifications and/or contaminate subsequent 
canister sampling events. Additionally, organic PM can react with co-
sampled ozone or other oxidative species to form target VOCs. PM can 
also clog tiny openings in critical or restrictive orifices, which 
impacts collection flow rates.
    (3) Under certain conditions, the composition of an air sample may 
change upon its introduction into the canister and over time such that 
the air in the canister no longer represents the air sampled. Such 
changes may be caused by interactions of the VOCs with the interior 
canister surface or between chemicals in the air matrix. The activity 
of the interior canister surface is unique to each canister and is 
based on several factors, including variability in canister 
manufacturing defects, differences in

[[Page 43278]]

canister surface deactivation treatments, the presence of PM and co-
collected moisture in the canister, and artifacts from reactions of 
VOCs on the canister walls.
    (4) Condensed water within the canister can result in corrosion of 
the interior surface of canisters with weak or deficient coatings and 
can result in the partitioning of hydrophilic polar VOCs to liquid 
water. Under such circumstances, concentrations of these analytes in 
the gas phase will be biased low until the condensation is eliminated 
by reduction of the canister pressure below the vapor saturation 
pressure of water.
    4.3 Analytical Interferences. Contamination within the analytical 
system may come from several sources including, but not limited to, 
off-gassing of materials within the sample introduction or 
preconcentrator flow path, carryover from high-concentration samples or 
standards, and solvent vapors within the laboratory.
    (1) Active sites within the sample introduction or preconcentration 
flow path are often caused by use of improper materials or degradation 
of deactivated surfaces.
    (2) Impurities in source materials or diluent gases for internal 
standard (IS) gas mixtures may result in contamination of target VOCs.
    (3) Water and the delivery systems used to humidify canisters or 
diluent gas streams may contaminate the canister contents or humidified 
gases.
    (4) Moisture in the sample gas may interfere with VOC analysis by 
GC-MS. Poor or inconsistent water management during preconcentration 
can cause peak broadening and RT shifts that can result in peak 
misidentification, particularly for hydrophilic polar compounds. Water 
management systems that use semipermeable fluoropolymer membranes 
remove oxygenated and polar VOCs from the sample matrix and exhibit 
memory effects for several VOCs. VOCs entrained in the fluoropolymer 
membrane can convert to ketones and alcohols, which are transported 
across the membrane bidirectionally such that these ketones and 
alcohols can contaminate the sample stream and VOCs in the sample 
stream can be adsorbed into the fluoropolymer and removed from the 
sample stream.
    (5) Carbon dioxide in the collected sample can coelute with more 
volatile VOCs eluting early in the GC-MS run and interfere with their 
quantitation.
    (6) Artifacts in chromatograms, such as silanol compounds formed 
from the breakdown of silicon-ceramic linings of canisters and siloxane 
compounds from the breakdown of the stationary phase in an analytical 
column, can interfere with identification and quantitation of less 
volatile VOCs.
    (7) Be cognizant of compounds that interfere with target analytes 
when operating in MS modes that do not provide full-scan ion spectra 
(i.e., selected ion monitoring [SIM] and selected ion storage [SIS]). 
Such interfering coeluting compounds may share common ions, may have 
similar mass spectra, and may be difficult or impossible to separate 
from target VOCs.

5.0 Safety

    This method does not address all the safety concerns associated 
with its use. It is the responsibility of the user of this standard to 
establish appropriate field and laboratory safety and health practices 
prior to use.

6.0 Equipment and Supplies

    6.1 Specially Prepared Canisters. You must use specially prepared 
canisters at least 6 liters in volume that are suitable for trace gas 
analysis of the target compounds, such that they meet the requirements 
in Section 8.3 of this method. Canisters must be able to withstand 
numerous cycles of evacuation to high vacuum of 0.0067 kPa (0.002 in. 
Hg) and pressurization to 377 kPa (40 pounds per square inch gauge, 
psig).
    6.2 Valves. You must use canisters with valves that are designed 
specifically for trace level measurements. The wetted portions of the 
valve must, at a minimum, be constructed of chromatographic-grade 
stainless steel (preferably type 316), and the valve seal surfaces must 
be metal to metal to minimize absorption and off-gassing of VOCs and 
other potential contaminants. It is recommended that valve designs have 
minimal internal volume and surface area to minimize the risk of 
contamination.
    6.3 Canister Cleaning System. You must use a canister cleaning 
system that includes the following components.
    6.3.1 Manifold constructed of chromatographic-grade stainless-steel 
tubing and connections for multiple canisters.
    6.3.2 Oil-free vacuum pump capable of achieving vacuum of 
approximately 3.4 kPa absolute (1 in. Hg absolute or 0.5 psia).
    6.3.3 High-vacuum pump for achieving a final canister vacuum of 
approximately 0.0067 kPa (0.002 in. Hg) or less.
    6.3.4 Heating oven that can contain the canister and allow heating 
of the valve. The oven is also used to bake sampling system components.
    6.3.5 Humidification system, such as humidifier impinger or 
bubbler, capable of achieving relative humidity (RH) of at least 50% in 
the cannister.
    6.3.6 Programmable controller for selecting temperature and cycle 
time and for manually or automatically switching between evacuation and 
pressurization.
    6.3.7 A pressure release valve to minimize the likelihood of system 
over pressurization.
    6.3.8 Tubing and connections constructed of borosilicate glass, 
quartz glass, or chromatographic-grade stainless-steel (minimum type 
316 or silicon-ceramic coated) to minimize dead volume of the system. 
You must not use butyl rubber or perfluoroalkoxy (PFA) materials. If 
needed for connections or seals, minimize the use of Viton and Teflon 
to avoid adsorption and/or off-gassing of compounds of interest or 
introduction of other potential interferences.
    6.3.9 Purge gas such as HCF zero air or ultra-high purity (UHP)-
grade cylinder nitrogen or liquid nitrogen dewar headspace.
    6.3.10 Charcoal scrubber, catalytic oxidizer, or other systems for 
eliminating trace contaminants from the purge gas.
    6.4 Sampling Device. The sampling device consists of the following 
equipment and for the purpose of this method, the sampling device 
consists of the aggregation of equipment in this section. The sampling 
device must be individually named with an alpha-numeric serial number 
that is unique.
    6.4.1 A stainless-steel particulate filter with pore size of 2 to 7 
micrometers ([mu]m) installed on the sampling device inlet.
    6.4.2 Sampling Probe. The internal volume of the sample probe must 
be less than 1% of the volume collected by the sample container with an 
inverted inlet (e.g., sampling cane to prevent the entry of water 
droplets) consisting of only chromatographic-grade stainless steel 
(including silicon-ceramic lined steel) placed 1.5 to 3 meters (4.9 to 
9.8 feet) above the ground.
    6.4.3 You must use an MFCD to regulate the flow at a constant flow 
rate over the 24-hour collection period into an evacuated stainless-
steel canister.
    6.4.4 Canister Sampling Timers (Optional). A device with an inert 
valve that can be programmed to automatically start and stop canister 
sampling periods
    6.5 Vacuum/Pressure Gauges.
    6.5.1 Field Pressure Measurement Gauge. A vacuum/pressure gauge or 
pressure transducer with an accuracy of 0.25% full scale 
calibrated over the

[[Page 43279]]

range of use for the application with sufficient resolution to permit 
precise measurement of pressure differentials must be used for field 
sampling purposes. The accuracy of the vacuum gauge must be measured 
verified on an annual basis against a National Institute of Standards 
and Technology (NIST)-certified standard.
    6.5.2 Laboratory Canister Pressure Measurement Gauge. A vacuum/
pressure gauge or pressure transducer with an accuracy of 0.1% full scale or 0.13 kPa, whichever is smaller, calibrated 
over the range of use for the application with sufficient resolution to 
permit precise measurement of canister pressure must be used for 
pressurizing field samples with HCF zero air or ultrapure nitrogen for 
analysis. The accuracy of the vacuum gauge must be measured verified on 
an annual basis against a NIST-certified standard for analysis.
    6.6 Gas Regulators. Regulators for high-pressure cylinders of 
dilution gas, stock standard gases, and internal standard gases must be 
constructed of non-reactive material, such as high-purity stainless 
steel, and may be lined with an appropriate material that is inert to 
the targeted VOC (e.g., silicon-ceramic). Do not use regulators that 
contain PFA materials (e.g., for seals and diaphragms) and avoid using 
regulators that contain Teflon products such as polytetr-
rafluoroethylene (PTFE) and flouroethylenepropylene(FEP), where 
possible, to minimize memory effects. All regulators must be rated for 
the pressure and flow expected during use. Regulators must be dedicated 
to a specific task and labeled for use (e.g., do not use the same 
regulator on a high-concentration stock VOC standard cylinder and a 
low-concentration stock VOC cylinder).

    Note: Some new regulators (e.g., stainless steel regulators) 
should be sufficiently passivated prior to use to prevent potential 
sample loss.

    6.7 Reference Flow Meters.
    6.7.1 A flow meter (e.g., a calibrated mass flow meter (MFM), a 
volumetric reference standard, or other similar measurement device) 
calibrated to measurement range appropriate to measure continuous flow 
must be used. The flow meter must not interfere with the flow 
measurement (i.e., the pressure drop across the flow meter may affect 
the flow being measured).
    6.7.2 Reference flow meters must be calibrated on an annual basis 
and be able to measure within 2% of the predicted values 
(e.g., cubic centimeters per minute) against a NIST-traceable 
volumetric standard.
    6.8 Tubing and Fittings. Connecting tubing and fittings for 
dilution and standard gases must be constructed of chromatographic-
grade stainless steel (e.g., 316 type), which includes silicon-ceramic-
treated stainless steel. Connections must be metal to metal. Lines may 
need to be heated to ensure that there is no condensation. You must not 
use PTFE thread sealants or Buna-N rubber components on any wetted 
surface in a sampling and analytical system.
    6.9 Analytical Instrumentation. Conduct analyses under this method 
using any combination of preconcentrator, GC, and MS provided the 
equipment meets the performance specifications of this method.
    6.9.1 Gas Chromatographic-Mass Spectrometric (GC-MS) System.
    6.9.1.1 Gas Chromatograph. The GC used for analysis under this 
method must allow temperature programming with quick and accurate 
temperature ramping. If needed for separation of very light VOCs from 
the targeted oHAPs, the GC must be capable of sub-ambient cooling 
(e.g., -50 [deg]C). Carrier gas connections must be constructed of 
stainless-steel or copper tubing.
    6.9.1.2 Chromatographic Column. The capillary chromatographic 
column must be capable of achieving separation of target compounds and 
any potential interferences per Section 4 and maintaining retention 
time stability as required in Section 9.
    6.9.1.3 Mass Spectrometer. The MS may be a linear quadrupole, ion 
trap, or TOF unit, and must have minimum resolution of 1 atomic mass 
unit (amu) or less. The MS must be capable of analyzing the desired 
mass range every 1 second or less and operate with an acquisition rate 
such that at least 12 measurements are performed over a typical 
chromatographic peak. Quadrupole and ion trap systems employing 
electron impact (EI) ionization mode must provide nominal 70 volt (V) 
electron energy in EI mode to produce a bromofluorobenzene (BFB) mass 
spectrum that meets all the instrument performance acceptance criteria 
as specified in this method.
    6.10 Calibration Gas Standard Preparation Equipment. This section 
discusses the equipment needed to prepare working-level standards for 
calibrating the GC-MS by dilution of a higher concentration stock 
standard gas.
    6.10.1 Dynamic Dilution System Instrumentation.
    6.10.1.1 The dynamic dilution system must include, at a minimum, 
calibrated electronic mass flow controllers (MFCs) for the diluent gas 
and each standard gas to be diluted, a humidifier for the diluent gas, 
and a manifold or mixing chamber where the diluent and standard gases 
can be sufficiently combined before introduction to the preconcentrator 
or canister. The gas dilution system must produce calibration gases 
whose measured values are within 2% of the predicted 
values. The predicted values are calculated based on the certified 
concentration of the supply gas (protocol gases, when available, are 
recommended for their accuracy) and the gas flow rates (or dilution 
ratios) through the gas dilution system.
    6.10.1.2 Connection tubing for the dynamic dilution system must be 
constructed of chromatographic-grade or silicon-ceramic-coated 
stainless steel. Mixing chambers or manifolds must be constructed of 
chromatographic-grade or silicon-ceramic-coated stainless steel, 
borosilicate, or quartz glass.
    6.10.1.3 The gas dilution system must be recalibrated at least once 
per two calendar years using NIST-traceable primary flow standards with 
an uncertainty <=0.25%. You must report the results of the calibration 
whenever the dilution system is used, listing the date of the most 
recent calibration, the due date for the next calibration, calibration 
point, reference flow device (device identification [ID], serial number 
[SN], and acceptance criteria.
    6.10.1.4 The gas dilution system must be verified to be non-biasing 
under HFC zero air and known standards at least one per calendar year 
for each reactive target compounds (e.g., ethylene oxide and vinyl 
chloride). Zero air must be flowed through all applicable MFCs, tubing, 
and manifold used and verified to not be detectable for the target 
compounds. Additionally, a known standard within the calibration range 
of the analytical system for each target compound must be flowed 
through all applicable MFCs, tubing, and manifold to allow 
equilibration and verified to not bias the standard by 15% 
of the concentrations in the reference sample. The equilibration time 
for the bias verification must be used at a minimum for the development 
of standards.
    6.10.1.5 The gas dilution system MFCs used must be verified 
quarterly, at a minimum, per Section 3.2 of Method 205 using any 
available protocol gas and corresponding reference method.
    6.10.2 Static Dilution System Instrumentation.
    6.10.2.1 The static dilution system must include, at a minimum, a 
calibrated pressure transducer or pressure gauge to measure the partial 
pressures of each standard gas to be diluted and the balance gas, and a

[[Page 43280]]

manifold to introduce the gases into the working standard canister or 
vessel. Pressure transducer(s) or pressure gauge(s) used for static 
dilution must have an accuracy of 0.1% full scale or 0.13 
kPa, whichever is smaller, calibrated over the range of use for the 
application with sufficient resolution to permit precise measurement of 
pressure differentials.
    6.10.2.2 Connection tubing for the static dilution system must be 
constructed of chromatographic-grade or silicon-ceramic-coated 
stainless steel. Manifolds must be constructed of chromatographic-grade 
or silicon-ceramic-coated stainless steel, borosilicate, or quartz 
glass.
    6.10.2.3 The static gas dilution system must be recalibrated once 
per calendar year using NIST-traceable primary pressure gauge with an 
uncertainty <=0.1%. You must report the results of the calibration 
whenever the dilution system is used, listing the date of the most 
recent calibration, the due date for the next calibration, calibration 
point, reference flow device (ID, S:N ratio), and acceptance criteria.
    6.10.2.4 The gas dilution system must be verified to be non-biasing 
under HFC zero air and known standards at least one per calendar year 
for each reactive target compounds (e.g., ethylene oxide and vinyl 
chloride). Zero air must be flowed through all applicable tubing and 
manifold used and verified to not be detectable for the target 
compounds. Additionally, a known standard within the calibration range 
of the analytical system for each target compound must be flowed 
through all applicable tubing and manifold into the standard canister 
or vessel and verified to not bias the standard by 15% of 
the concentrations in the reference sample.
    6.11 Calibrated Hygrometer.
    6.11.1 The calibrated hygrometer must be capable of a 1% RH 
resolution with a yearly calibration to a NIST-traceable accuracy of 
3% RH within the range of 20% to 80% RH.
    6.11.2 The calibration hydrometer calibration must be verified 
weekly or per use (whichever is less stringent) at a single point that 
is approximatively 40 to 50% RH to within 5% using a second 
calibrated hygrometer or a saturated salt solution.

7.0 Reagent and Standards

    7.1 You must use only NIST-certified or NIST-traceable calibration 
standards, standard reference materials, and reagents that are stable 
through certification and recertification for the tests and procedures 
required by this method. You must use standards and reagents within 
their expiration period and evaluate working-level standards prepared 
in canisters within 30 days of preparation. The concentrations of the 
target compounds in the mixture must be commensurate with the 
anticipated dilution factor achievable by the laboratory needed to 
dilute the mixture to the desired working range. You must retain and 
report the gas standard certificates of analysis.
    7.2 Carrier Gas. Use helium, hydrogen, or nitrogen as the carrier 
gas in the GC. Carrier gas must be ultrapure (99.999% pure or better).
    7.3 HCF Zero Air. Purchase HCF zero air in high-pressure cylinders 
from reputable gas vendors or prepare HCF zero air by passing ambient 
air through molecular sieves, catalytic oxidizers, and subsequent 
charcoal filters or similar substrate. HFC zero air must contain 
impurities less than 20 pptv or undetected (whichever is more 
stringent) per compound of interest.
    7.5 Nitrogen. Use ultrapure (99.999% pure or better) nitrogen from 
cylinders procured from commercial gas vendors or from the headspace 
gas from a liquid nitrogen dewar.
    7.6 Cryogens. Cryogens (e.g., liquid nitrogen, liquid argon, and 
liquid carbon dioxide) specified by the instrument manufacturer, if 
needed.
    7.7 Water for Canister Humidification. ASTM Type I (resistivity 
>=18 megaohm-centimeter [M[ohm][middot]cm]) or equivalent.

8.0 Sample Collection and Preparation

    This section presents the sample collection and handling procedures 
of this method with the initial and ongoing performance evaluation of 
materials used in sampling and analysis. This method allows the user to 
choose the materials used for sampling. You must record the exact 
materials used when conducting this method and include that information 
in any report associated with sampling according to this method.
    8.1 Sampling Device Performance Tests. Prior to initial field 
deployment and as directed in this section, you must verify that all 
equipment used to conduct this method meets the performance criteria 
specified in this section. The primary objectives of the performance 
tests in this section are to characterize the sampling system and to 
verify that the sampling system used meets the criteria in the method. 
The sampling system performance tests include the following:
    (a) Flow control verification test,
    (b) Flow control flow check,
    (c) Sampling device leak check,
    (d) Sampling device bias check, and
    (e) Sampling device standard check.
    8.1.1 Flow Control Verification Test. Prior to initial field 
deployment and at least every twelve months, you must verify that the 
sampling device's ability to control flow to the canister is 
acceptable. Assemble an evacuated canister with the sampling device 
including filter connected to a certified flow meter. Figure 1 of 
Section 17 of this method provides an illustration of the apparatus for 
characterizing the flow control device.
    8.1.1.1 Open the evacuated canister, monitor and record (manually 
or electronically) the canister pressure downstream of the flow control 
device and the flow upstream of the flow control device on an hourly 
basis over the period of 24-hours.
    8.1.1.2 The flow control verification test is considered acceptable 
when the sampling apparatus maintains a constant flow rate for 24-hours 
and until at least 75% of the canister volume is collected, which is 
equivalent to approximately 28 kPa (7 in. Hg or 4 psia) below 
atmospheric pressure.
    8.1.1.3 Record the average flow rate during this test. This value 
will be the reference flow rate for the sampling device until the next 
verification test. Maintain the results as part of a laboratory record 
associated with the sampling device.
    8.1.2 Flow Control Flow Check. Prior to and after each field 
sampling event, establish or verify the flow rate of the sampling 
apparatus. This verification must occur in the field prior to and after 
each field event.
    8.1.2.1 Assemble an evacuated canister and the sampling device 
connected to a certified flow meter in the same manner used for the 
flow control verification test discussed above.
    8.1.2.2 Open the evacuated canister, allow sufficient time for the 
system to stabilize, and record the flowrate upstream of the flow 
control device. Collect two additional flow rate measurements.
    8.1.2.3 Calculate the average flowrate. The flow control flow check 
is considered valid if within 10% of the reference flow 
rate.
    8.1.2.4 If the flow rate has changed and is outside the desired 
range, you must either adjust or replace the controller and repeat the 
flow check.
    8.1.3 Sampling Device Leak Check. You must demonstrate the sampling 
device and sampling system are leak-free immediately before you begin 
sampling.
    8.1.3.1 Install the sampling device on an evacuated canister 
equipped with

[[Page 43281]]

a MFCD and tightly cap the inlet to the sampling device.
    8.1.3.2 Open the canister valve fully, and then re-close the valve 
and observe the vacuum/pressure gauge for a minimum of 2 minutes.
    8.1.3.3 If you observe an increase in pressure, the sampling device 
does not qualify as leak-free. If no changes are observed, record the 
data and time of the leak check on the Field Data Page (see Figure 4 in 
Section 17 of this method for an example).
    8.1.4 Sampling Device Bias Check. You must demonstrate that 
sampling device is non-biasing under zero-air and known-standard 
conditions. For the procedures in Sections 8.1.5 and 8.1.6 of this 
method, you must use only canisters that have been qualified as 
specified in Section 8.3 of this method.
    8.1.5 Sampling Device Zero-Air Challenge. You must conduct the 
sampler bias test at least every twelve months, and after cleaning, 
replacement of components, or collection of potentially contaminating 
samples. The volume of air analyzed for the zero-air and reference 
standard gas must be consistent with the laboratory's typical canister 
sample injection volume or nominal volume.
    8.1.5.1 Provide humidified (>40% RH) HCF zero air through the 
sampling device into the canister, and then analyze the sample 
according to Section 11 of this method and record the concentration 
measurement and maintain the results as part of a laboratory record 
associated with the sampling device.
    8.1.5.2 The results must show that the concentration of the target 
compounds in the zero-air challenge sample collected through the 
sampling unit is not greater than 20 pptv higher than the native 
concentration of the target compounds in the reference sample (sample 
of zero-air collected upstream of the sampling device) or not detected 
at 22.1 psi absolute (152 kPa absolute) whichever is more stringent. If 
a sampling device does not meet this performance criteria, take action 
to remove the contamination attributable to the sampling unit (e.g., 
purging with humidified HCF zero air overnight or longer) and repeat 
the zero-air challenge. You must not use a sampling device that has not 
met the standards in this section.

    Note: If extended purging durations are not adequate to 
eliminate contaminants, then disassemble and clean according to 
Section 8.4 of this method. If the unit cannot be cleaned to meet 
the specifications, retire the unit from use or repurpose for source 
sampling.

    8.1.6 Sampling Device Standard Check. You must conduct the sampling 
device standard check prior to initial use and at least every twelve 
months, and after replacement of components, or collection of 
potentially contaminating samples. For the procedures specified below, 
you must use only canisters that have been qualified as specified in 
Section 8.3 of this method.
    8.1.6.1 Collect a humidified (>40% RH) known-standard challenge gas 
through the sampling device and into a canister. The challenge gas must 
contain the target oHAPs at 100 to 500 pptv each and you must choose 
the selected challenge concentration considering the expected measured 
concentration at the deployment location(s).
    8.1.6.2 Analyze the sample according to Section 11 of this method 
and record the concentration measurement and maintain the results as 
part of a laboratory record associated with the sampling device. The 
results must demonstrate that each oHAP in the sample collected through 
the sampling device must be within 15% of the 
concentrations in the reference sample. For compounds exceeding this 
criterion, you must take steps to eliminate the bias (e.g., cleaning as 
specified in Section 8.6.1 of this method or replacement of compromised 
parts) and repeat the known-standard challenge.
    8.1.6.3 Following successful completion of the known-standard 
challenge, flush the sampling device or system with humidified (>50% 
RH) HCF zero-air or ultrapure nitrogen until the device meets the 
criteria specified in Section 8.1.5.2 prior field deployment.
    8.2 Qualification of Analytical Instrumentation. Prior to initial 
use and as directed in this section, you must verify that the 
analytical equipment used in performing this method meets the 
performance criteria in this section. The primary objectives of these 
performance tests are to characterize the analytical instrumentation 
and verify that the analytical instrumentation meets the criteria in 
this method. The analytical instrumentation performance tests consist 
of the following:
    (a) Analytical zero-air verification,
    (b) Analytical known-standard challenge for analytical 
instrumentation, and
    (c) Autosampler verification.
    8.2.1 Analytical Zero-Air Verification. Prior to initial use and as 
part of an instrument's annual calibration, you must demonstrate that 
the analytical instrumentation (preconcentrator, GC-MS system, and all 
connections) is non-biasing under zero-air. The volume of air analyzed 
must be consistent with the laboratory's nominal injection volume.
    8.2.1.1 Use the analytical instrumentation to analyze humidified 
(40 to 50% RH) HCF zero air from a known clean source (e.g., certified 
clean canister, clean cylinder gas, zero-air generator) at the 
installation prior to initial use of the instrument.
    8.2.1.2 Examine chromatograms for interferences and other 
chromatographic artifacts such as nontarget peak responses, large peaks 
or rises in the chromatogram due to undifferentiated compounds, and 
baseline anomalies. The analysis must show that the concentration of 
any detected target compounds in the zero-air challenge sample is <20 
pptv or undetected (whichever is more stringent) per compound of 
interest.
    8.2.1.3 If you identify exceedances of target compounds in the 
zero-air challenge, take steps (e.g., analyzing replicates of 
humidified clean gas until the contamination is eliminated) to remove 
the contamination attributable to the analytical instrumentation by 
following the manufacturer's instructions.
    8.2.1.4 You must repeat the analytical zero-air verification to 
ensure that you have mitigated any problems before using the analytical 
instrumentation.
    8.2.2 Analytical Known-Standard Challenge for Analytical 
Instrumentation. Prior to initial use and as part of an instrument's 
annual calibration, you must demonstrate that the analytical 
instrumentation (preconcentrator, GC-MS system, and all connections) is 
non-biasing under known standards. The volume of air analyzed must be 
consistent with the laboratory's nominal canister sample injection 
volume.
    8.2.2.1 Analyze a humidified (40 to 50% RH) reference standard in 
duplicate containing all target compounds at approximately 100 to 500 
pptv each, chosen in consideration of the expected concentration at the 
deployment locations.
    8.2.2.2 The results must demonstrate that the target compounds in 
the sample collected through the sampling device are within 15% of the expected concentrations in the sample.
    8.2.2.3 Compounds demonstrating poor response as indicated by peak 
absence or minimal peak area may be a result of active sites in the 
analytical system, cold spots in transfer lines, gas impurities, 
improper choice of preconcentrator sorbent traps or GC columns, system 
leaks, and/or poor moisture management. If you identify problems, 
consult the instrument

[[Page 43282]]

manufacturer to determine the necessary steps to eliminate the bias.
    8.2.3 Autosampler Verification. Prior to initial use and as part of 
an instrument's annual calibration, you must demonstrate that the auto 
sampling equipment is non-biasing under zero-air.
    8.2.3.1 If you use an autosampler to facilitate analysis of 
multiple canisters, you must test all ports, transfer lines, and 
connections of the autosampler after you have calibrated the analytical 
system and prior to conducting the canister, sampling device and system 
qualifications, or upon replacement of transfer lines or after analysis 
of potentially contaminating samples.
    8.2.3.2 Connect humidified (40 to 50% RH) HCF zero air to each port 
and verify that the concentration for each target compound is <20 pptv 
or undetected (whichever is more stringent) per compound of interest 
using the procedures in Section 11 of this method.
    8.2.3.3 After the zero-air test, challenge each port of the 
autosampler with a reference standard (approximately 100 to 500 pptv) 
to verify that the autosampler is not causing bias using the procedures 
in Section 11 of this method). The concentration of each target 
compound must be within 15% of the theoretical 
concentration of the reference standard.
    8.3 Qualification of Canisters. Prior to initial use and as 
directed in this section, sampling canisters must meet the performance 
criteria in this section. The primary objectives of these performance 
tests are to ensure canisters are well characterized and to verify they 
are non-biasing. The performance criteria in this section are specific 
to the application of fenceline measurements for regulatory purposes at 
stationary sources. The performance test consists of the following:
    (a) Canister design,
    (b) Canister leak check,
    (c) Canister zero-air verification, and
    (d) Canister known-standard verification.
    8.3.1 Canister Design.
    8.3.1.1 You must use specially prepared canisters at least 6-liters 
volume in size that are suitable for trace gas analysis of the target 
compounds. The canister must include a fixed on/off valve made from 
chromatographic-grade stainless with metal valve seal surfaces. Each 
canister must also include a permanent alpha-numeric serial number for 
identification purposes. Alternative canister volumes may be used, 
subject to approval by the Administrator.

    Note: Specially prepared canisters are commercially available 
with a modest range of options for surface preparation of the 
canister interior surfaces, valves, and connections. Currently, 
canister interior surfaces are typically passivated by 
electropolishing or coating with a silicon-ceramic film. EPA does 
not require a specific treatment or design and any canister type may 
be used for this method contingent on meeting the performance 
criteria in this section; however, silicon-ceramic coated canisters 
have demonstrated superior performance when used to sample reactive 
compounds, (e.g., ethylene oxide).

    8.3.1.2 Canisters should be handled with care to ensure that the 
interior canister surface is not compromised, the valve-to-canister 
connection remains intact, and weld integrity is maintained. Excessive 
torque on unbraced canister valve stems when making connections may 
cause damage and potentially leaks in the valve stem weld or at the 
ferrule sealing the canister valve and canister stem. Shocks resulting 
in dents to the surface of the canister may damage welds or create 
small cracks in the interior canister surface that may expose active 
sites. You must not use any canister with dents or compromised welds.
    8.3.1.3 You must maintain a record of the results for all canisters 
used for this method. It is recommended that you evaluate the results 
for any potential trends that could result in erroneous data.
    8.3.2 Canister Leak Check. You must qualify each canister as being 
acceptably leak-tight to ensure sample validity. Qualify new canisters 
before initial use and qualify all canisters used for sampling at least 
annually.
    8.3.2.1 Leak Check. In conducting the canister leak check, you can 
either evacuate the canister to high vacuum <=0.0067 kPa absolute 
(0.002 in. Hg or 0.001 psia) or pressurize the canister with clean fill 
gas to >203 kPa absolute (60 in. Hg or 29.4 psia).
    8.3.2.2 After establishing the target pressure in the canister, 
close the valve and attach a vacuum/pressure gauge.
    8.3.2.3 Open the valve and record the initial pressure reading.
    8.3.2.4 Close the valve, remove the vacuum/pressure gauge, and 
loosely cap the canister using a cap fitting to ensure that leakage 
through the valve is accurately assessed while avoiding potential entry 
of debris into the valve during storage.
    8.3.2.5 After a minimum of two days in storage, reinstall the 
vacuum/pressure gauge, open the valve, and record the canister pressure 
reading.
    8.3.2.6 Determine the pressure decay rate as the absolute value of 
the difference between the initial and post-storage canister pressures. 
You must remove the canister from service if the pressure decay rate 
exceeds 0.69 kPa/storage day (0.2 in. Hg or 0.1 psia/storage day).
    8.3.3 Canister Zero-Air Verification. You must qualify each 
canister as being acceptably non-biasing under zero-air conditions to 
ensure sample validity. Qualify new canisters before initial use and 
qualify all canisters used for sampling at least once every 18 months.
    8.3.3.1 Pressurize the clean evacuated canister with humidified 
(>50% RH) HCF zero air to 152 kPa absolute (22.1 psia). Do not use 
ultrapure nitrogen to pressurize the canister because the inert 
nitrogen atmosphere does not permit reactions within the canister that 
may occur under sampling conditions.

    Note: Canister Zero-Air Verifications must also be performed 
after canister disassembly and/or replacement of components. Also, 
more frequent zero-air verifications may be appropriate when 
canisters are used in areas with higher ambient VOC concentrations 
or for collection of potentially contaminating samples.

    8.3.3.2 Allow the canister to equilibrate for a minimum of 24 
hours.
    8.3.3.3 After the equilibration period, conduct an initial 
cleanliness analysis as specified in Section 8.4 of this method.
    8.3.3.4 Store the canister for a holding period equal to or 
exceeding the typical laboratory holding time, nominally 8 days from 
the canister fill date.
    8.3.3.5 After the holding period, conduct a subsequent cleanliness 
analysis as specified in Section 8.5 of this method.
    8.3.3.6 The results of both the initial and subsequent cleanliness 
analysis must meet the cleanliness criteria specified in Section 8.5 of 
this method to be used for sampling. You must reclean and retest 
canisters that fail the zero-air challenge.

    Note: If necessary, use more aggressive cleaning techniques such 
as water rinses or other rinses as specified by manufacturers. If a 
canister continues to fail the zero-air challenges, remove the 
canister from service.

    8.3.4 Canister Known-Standard Verification. You must qualify each 
canister as being acceptably non-biasing under known-standard 
conditions to ensure sample validity. Qualify new canisters before 
initial use and qualify all canisters used for sampling at least every 
18 months.
    8.3.4.1 Fill the clean evacuated canister with a humidified (40 to 
50% RH) standard gas in HCF zero air with each target compound at 
approximately 100 to 500 pptv. Choose the selected challenge 
concentration based on the

[[Page 43283]]

concentration expected to be measured during the sampling event.
    8.3.4.2 Allow the canister to equilibrate for a minimum of 24 
hours.
    8.3.4.3 After the equilibration period, conduct an initial analysis 
according to Section 11 of this method.
    8.3.4.4 Store the canister for a holding period equal to or 
exceeding the typical laboratory holding time, nominally 8 days from 
the canister fill date.
    8.3.4.5 After the holding period, conduct a subsequent analysis.
    8.3.4.6 The results of both the initial and subsequent analysis 
must show that the measured concentrations of the target analytes are 
within 30% of the theoretical spiked concentration for each 
target compound. You must reclean and retest canisters that fail the 
known-standard verification.
    8.4 Canister Cleaning. Clean canisters using repeated cycles of 
evacuation and pressurization. Table 1 in Section 17 of this method 
summarizes the canister cleaning procedures.
    8.4.1 Gas Source for Canister Cleaning, Pressurization, and 
Flushing.
    8.4.1.1 Verify, by direct analysis, the cleanliness of the purge 
gas upon initial setup. The analysis must show that the concentration 
of the individual target compounds is <=20 pptv or undetected 
(whichever is more stringent) per compound of interest at 101.3 kPa 
absolute (29.92 in. Hg or 14.7 psia).
    8.4.1.2 Humidify the purge gas to >50% RH and measure the humidity 
by placing a calibrated hygrometer probe in the humidified gas stream.
    8.4.1.3 If using a bubbler-type humidifier, ensure that the 
downstream pressure is lower than the humidifier upstream pressure to 
avoid backflow of the water.
    8.4.2 Pre-Evacuation of Canisters. You may need to repeat the pre-
evacuation process for canisters that contain VOCs at higher 
concentrations.
    8.4.2.1 Pre-evacuate canisters to be cleaned prior to connection to 
the canister cleaning system. To reduce the potential for contamination 
of the system, attach the canisters to an oil-free roughing pump and 
evacuate to approximately 7 kPa absolute (28 in. Hg vacuum or 1.0 psia) 
with the exhaust of the pump directed to a fume hood or passed through 
a charcoal trap.
    8.4.2.2 Refill canisters to ambient pressure with HCF zero air.
    8.4.2.3 Attach the canisters to the cleaning system after 
completing the pre-evacuation and refilling steps.
    8.4.3 Canister Heating During Cleaning.
    8.4.3.1 Heat canisters by placing them in an enclosed oven during 
cleaning to facilitate removal of compounds. Do not use heat bands or 
heating jackets.
    8.4.3.2 Table 1 of Section 17 of this method specifies the 
temperatures to use for canister cleaning procedures.
    8.4.4 Canister Evacuation and Pressurization Cycling.
    8.4.4.1 Evacuate canisters to minimally 7 kPa absolute (28 in. Hg 
vacuum or 1 psia) and maintain this vacuum for a at least 1 minute.
    8.4.4.2 Pressurize canisters to 414kPa absolute (<=30 psig) with 
humidified (>50% RH) HCF zero air and maintain this pressure for a 
minimum of 1 minute.
    8.4.4.3 Repeat the cycle of canister evacuation and pressurization 
specified in Sections 8.4.4.1 and 8.4.4.2 of this method at least 5 
times. You may need to perform 10 to 20 cycle repetitions or use other 
ancillary procedures to remove stubborn interferents or oxygenated 
compounds such as ketones, alcohols, and aldehydes (U.S. EPA, 2016b).
    8.5 Verification of Canister Cleanliness Prior to Sample 
Collection.
    8.5.1 After cleaning, pressurize each canister from the batch with 
humidified HCF zero air and maintain that pressure for at least 24 
hours.
    8.5.2 Connect each canister to the analytical system and measure 
the concentration of each target compound according to the procedures 
in Section 11 of this method.
    8.5.3 The canister background concentration for each target 
compound must be <=20 pptv (0.02 ppbv) or undetected (whichever is more 
stringent) when a canister is filled to 22.1 psi absolute (152 kPa 
absolute).
    8.5.4 Canisters that meet the blank criteria are suitable to be 
evacuated for use. If a canister fails to meet the criteria, you must 
not use that canister until it has been re-cleaned and has met the 
requirements in Section 8.5.3 of this method.
    8.5.5 Prior to field deployment, evacuate canisters to <=0.0067 kPa 
(<=0.002 in. Hg or 0.001 psia).
    8.6 Cleaning of Sampling Components.
    8.6.1 Follow the manufacturer's instructions for cleaning 
components such as flow controllers and sampling unit parts, when 
necessary.

    Note: Disassembly of such instruments may void warranties or 
calibrations.

    8.6.1.1 Flush the sampling units with humidified HCF zero air to 
remove contamination for at least 15 minutes.
    8.6.1.2 Disassemble sampling components and visually inspect for 
cracks, abrasions, and residue prior to sonicating in deionized water 
for at least 30 minutes.
    8.6.1.3 After flushing/sonication, rinse the components with clean 
deionized water and dry the components in an enclosed oven set to at 
least 50 [deg]C for a minimum of 12 hours.
    8.6.1.4 Following drying, reinspect components for defects, 
reassemble, and flush the sampler with humidified HCF zero air or 
ultrapure nitrogen for at least 12 hours.

    Note: To avoid damage to deactivated stainless-steel components 
due to oxidation in the presence of oxygen-containing atmospheres 
(e.g., HCF zero air), you should not heat components treated with 
silicon-ceramic coatings above 80 [deg]C unless evacuated or under 
an inert atmosphere (e.g., nitrogen).

    8.7 Sample Collection. Persons collecting field samples should be 
familiar with all aspects of this sampling protocol. It is suggested 
that those collecting these measurements for regulatory purposes 
develop site-specific SOPs to ensure samples are collected consistently 
and those doing the sampling are sufficiently trained on this method 
and the SOP.
    8.7.1 Pre-Sampling Activities.
    8.7.1.1 Clean canisters and verify that the canisters meet 
cleanliness and vacuum criteria specified in Sections 8.3 through 8.5 
of this method.
    8.7.1.2 If canisters were previously cleaned and stored under 
pressure while awaiting use, you must evacuate the canisters prior to 
field deployment. If canisters were stored under vacuum, you must 
verify that the canisters continue to meet vacuum threshold 
requirements.
    8.7.1.3 Clean and verify the cleanliness and flowrates of sample 
devices that you will use for sampling and ensure that a clean 
particulate filter is placed in the inlet of the sampling device.
    8.7.1.4 Establish sample codes (unique identifiers) and develop 
field data page and/or chain of custody (COC)/sample collection data 
form(s).
    8.7.1.5 If shipping equipment into the field, make sure you have 
the proper number of canisters and sampling devices for the number of 
samples required for the sampling location and QC samples, allowing for 
sufficient timing for samples to arrive at the site.
    8.7.1.6 Develop a unique sampling location ID. The sampling 
location must meet any requirements set in the applicable regulation 
and be in a secure location that protects the canister and sampling 
inlet from unwanted tampering or damage. The sampling location must 
also be located away from

[[Page 43284]]

the immediate vicinity of any biasing sources (e.g., outdoor smoking 
areas; vehicle exhaust; heating, ventilation, and air conditioning 
units/building exhaust; outdoor fuel storage areas; shelter roofing 
materials; or exhaust from other sample collection devices). In 
general, horizontal distances should be >10 meters (m) from biasing 
sources.
    8.7.2 Sample Setup Activities.
    8.7.2.1 You must place the canister in a location that protects the 
canister and sampling inlet from unwanted tampering, damage, or theft.
    8.7.2.2 Protect the canister and sampling inlets by placing the 
canister under shelter, if possible. Do not restrict air flow around 
inlets and do not locate inlets under building overhangs.
    8.7.2.3 Do not place the canister near vegetation or structures 
that block or significantly restrict air flow to the MFCD inlet or 
manifold. Ensure that rain cannot be drawn directly into the MFCD, and 
the inlet heights must be approximately 1.5 to 3 m above ground level.
    8.7.3 Sample Setup and Deployment. Perform the following steps at 
the time of sample setup and deployment.
    8.7.3.1 Based on the applicable standard, determine the appropriate 
number and placement of sampling locations at the fenceline. The 
applicable standard will define the sampling schedule (e.g., one 
sampling event over a 5-day period) and the sampling period. All 
sampling locations must initiate sampling within 60 minutes of each 
other.
    8.7.3.2 You must document all activities associated with sampling 
on the field data page. (See Figure 4 in Section 17 of this method for 
an example field data page.) You may choose to use this field data page 
as the COC, or you may choose to establish a separate COC form. The 
chain of custody will accompany the canisters during shipment and 
collection to document sample handling and transport.
    8.7.3.4 Verify that each canister has been blanked within the last 
30 days. Label each canister with a sample ID code and record the 
canister and sample ID on the field data page. You must not use a use a 
canister for sampling that has not been blanked within 30 days of 
sampling.
    8.7.3.5 Verify the sample device is in working order and calibrate/
verify the flow rate setting, if applicable, with a reference flow 
meter. Record the sample device ID, expected flowrate, and the 
reference flowrate if calibrated/verified in the field, including the 
reference flow meter if applicable.
    8.7.3.6 Attach the sampling device to the canister and locate at 
the appropriate sampling location. Record the sampling location ID, 
latitude, longitude, date, and time that you installed the canister on 
the field data page.
    8.7.3.7 Measure and record the canister vacuum using the field 
pressure measurement gauge, and verify that the canister has not leaked 
and has sufficient vacuum to collect the sample. You must replace the 
canister if the initial pressure is not within -1 in. Hg absolute zero 
(-3.39 kPa or 0.5 psi).
    8.7.3.8 Conduct leak checks as specified in Section 8.3.2 of this 
method and record the results on the field data page.
    8.7.3.9 Open the canister valve. Record the date and time that you 
opened the valve as the start time, and record the initial canister 
vacuum/pressure and any other comments such as unusual events or 
conditions that may impact sample results on the field data page.
    8.7.3.10 Sample for the period as defined in the applicable 
standard (e.g., 24 hours +/-1 hour).
    8.7.3.11 At the end of the sampling period, close the valve. Record 
the date and time that you closed the valve as the end time.
    8.7.3.12 Remove the sampling device and attach the field pressure 
measurement gauge.
    8.7.3.13 Open the canister valve and measure and record the final 
canister vacuum/pressure and any other comments such as unusual events 
or conditions that may impact sample results on the field data page. 
Flag any canisters with a final pressure greater than -3 in. Hg gauge 
pressure (10.2 kPag or -1.5 psig).
    8.7.3.14 Disconnect the field canister pressure measurement gauge 
and replace with a cap.
    8.7.3.15 If applicable, verify the sample device is still in 
working order and verify the flow rate setting with a reference flow 
meter. Record the final flowrate on the field data page.
    8.7.4 Field Duplicates. For each sampling day, you must include the 
collection of a separate co-located sample for at least one sampling 
location. The collocated duplicate must be sampled using a discrete 
MFCD. The collection of the field duplicates must follow the same 
procedure and occur at the same time as the co-located field sample.
    8.7.5 Canister Field Blanks. For each sample day, you must collect 
canister field blanks. A canister blank is prepared by filling a 
canister with humidified clean diluent gas (prepared in the same manner 
as the method blank (MB) described in Section 9.3.2 of this method) to 
approximately 15 in. Hg  1 in. Hg . Record the pressure and 
transport to the field site(s) to accompany field-collected canisters. 
Canister field blanks are to be treated identically to field-collected 
samples in the field and laboratory including pressure checks, MFCD 
leak checks, etc. The field blanks are analyzed by interspersing them 
among the field samples.
    8.7.6 Canister Field Spike. For each sample day, you must collect a 
canister field spike. A canister field spike is prepared by filling a 
canister with humidified standard gas at a concentration in the lower 
third of the calibration curve for the target compound to approximately 
-15 in. Hg  1 in. Hg. The field spike canister is 
transported to the field site to accompany field-collected canisters 
and treated identically to field-collected samples in the field and 
laboratory, including pressure checks, MFCD leak checks, etc. The field 
spikes are analyzed by interspersing them among the field samples. 
Field spike acceptance criteria should be within 30% of the 
theoretical spiked concentrations.
    8.7.7 Prepare and secure the canisters for transport. You must ship 
canisters in protective hard-shell boxes and/or sturdy cardboard boxes 
to ensure canister longevity. Do not use boxes that have lost integrity 
or rigidity.
    8.8 Method Detection Limit (MDL) Determination. Determine the MDL 
under the analytical conditions selected (see Section 11 of this 
method) using the procedures in this section.
    8.8.1 Prepare at least seven blank samples according to the 
procedures Section 9.3.2 of this method using sampling media (i.e., 
canisters) that have been deployed in the field, and cleaned per 
Section 8.4 of this method. The blank samples must be prepared in at 
least three batches on three separate calendar dates and analyzed on 
three separate calendar dates according to the procedures in Section 11 
of this method.
    8.8.2 Prepare at least seven spike samples according to the 
procedures in either Section 10.2 or 10.3 of this method, at a 
concentration of the target compound within a factor of five of the 
expected detection limits. The spike samples must be prepared in at 
least three batches on three separate calendar dates and analyzed on 
three separate calendar dates according to the procedures in Section 11 
of this method.
    8.8.3 Compute the standard deviation for the replicate blank 
samples concentrations and multiply

[[Page 43285]]

this value by 3.14 to determine the blank MDL (MDLb).
    8.8.4 Compute the standard deviation for the replicate spike sample 
concentrations and multiply this value by 3.14 to determine the spike 
MDL (MDLs).
    8.8.5 Select the greater of MDLb or MDLs as the MDL for the 
compound of interest. The results must demonstrate that the method is 
able to detect analytes such as ethylene oxide at concentrations less 
than 20 pptv and at least 1/10th of the lowest concentration of 
interest (i.e., action-level), whichever is larger. If the MDL does not 
meet the concentration requirement, perform corrective action and 
repeat the MDL determination.
    8.8.6 MDL determinations must be repeated at least annually or 
whenever significant changes have been made to the sampling or 
analytical system.

    Note: The MDL calculation is based on single-tailed 99th 
percentile t static at six degrees of freedom. Additional blank or 
spike samples would increase the degrees of freedom.

9.0 Quality Control

    Table 9-1 in this section lists the quality control (QC) parameters 
and performance specifications for this method.
    9.1 Second Source Calibration Verification (SSCV) Standard.
    9.1.1 Prepare a humidified SSCV standard in a canister at a 
concentration in the lower third of the calibration curve. The SSCV 
standard must contain all compounds in the calibration mixture. The 
SSCV standard must be prepared independently from the calibration 
standards using a certified secondary source calibration standard.
    9.1.2 Analyze the SSCV after the initial calibration (ICAL). 
Recovery of each target oHAP in the SSCV standard must be within 30% of the theoretical concentration.
    9.2 Continuing Calibration Verification (CCV) Standard. Prepare a 
humidified CCV standard as a dilution of a certified standard in a 
canister at a concentration in the lower third of the calibration 
curve. This certified standard must be prepared from the same standard 
used for the ICAL standards.
    9.2.1 Analyze a CCV for each target oHAP prior to analyzing 
samples, after every 10 sample injections, and at the end of the 
analytical sequence. Prepare a humidified CCV standard as a dilution of 
a certified standard in a canister at a concentration in the lower 
third of the calibration curve. This certified standard must be 
prepared from the cylinder used for the ICAL standards.
    9.2.2 The internal standard (IS) area responses for each CCV 
standard must meet the criteria outlined in Section 10.8.1.5 of this 
method, and the quantitated concentrations of the target compounds for 
each CCV standard must be within 30% of the theoretical 
concentrations as determined using Equation 4 in Section 12 of this 
method.
    9.2.3 If the CCV is not within specifications, you must invalidate 
any results after the last successful CCV. You must investigate and 
address CCV failures and initiate corrective actions, including, for 
example, reanalyzing the CCV, preparing and analyzing a new CCV or 
standard canister, and performing a new ICAL.
    9.3 Blank Analyses. Analysis of all blanks must demonstrate each 
target compound is <20 pptv 14.7 psia or undetected (whichever is more 
stringent) per compound of interest. Unless otherwise stated, the 
volume used for analysis of blanks must match the volume of sample to 
be analyzed.
    9.3.1 Instrument Blanks (IB). Analyze an IB at the beginning of the 
sequence and prior to analysis of the ICAL standard and daily CCV 
standard.
    9.3.2 Method Blanks (MB). Analyze a laboratory MB prior to and 
following the ICAL in an ICAL sequence and prior to analyzing the CCV 
standard. The MB consists of a canister filled with humidified (40 to 
50% RH) clean diluent gas and is analyzed via the same instrument 
method as the standards and field samples in the analytical sequence. 
Your MB must be the same diluent used for sample dilution.
    9.3.3 Canister Field Blank. Analyze the canister field blank as 
part of the same analytical sequence as the accompanying field samples.
    9.3.4 Calibration Blank (CB). Analyze the CB when the ICAL is 
established and when preparing any new CCV standard using the same 
instrument method that was used for standards and field samples when 
establishing the ICAL. The CB consists of a canister filled with the 
humidified (40 to 50% RH) clean diluent gas sourced through the 
dilution system employed to prepare standards. For laboratories that do 
not employ a dynamic or automated static dilution system, the CB 
consists of a humidified (40 to 50% RH) canister of the gas used to 
dilute the calibration standard.
    9.4 Duplicate samples must be analyzed and reported as part of this 
method. They are used to evaluate sampling and/or analytical precision.
    9.4.1 Field Duplicate. The level of agreement between duplicate 
field samples is a measure of the precision achievable for the entire 
sampling and analysis. Analyze the field duplicate during the same 
analytical sequence as the accompanying field sample. The RPD of the 
precision measurements should agree within 30% when both 
measurements are >=5 times the MDL. Flag associated results to indicate 
if the RPD indicates poor method precision.
    9.4.2 Replicate Analysis. The level of agreement between replicate 
samples is a measure of precision achievable for the analysis. Analyze 
at least one replicate analysis for each set of field-collected 
samples. The RPD of the precision measurements should agree within 
25% when both measurements are >=5 times the MDL. Flag 
associated results to indicate if the RPD indicates poor method 
precision.

                                          Table 9-1--Quality Control Parameters and Performance Specifications
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Parameter                  Description and details           Required frequency              Acceptance criteria         Corrective action
--------------------------------------------------------------------------------------------------------------------------------------------------------
Analytical zero-air verification..  Test of instrumentation to      At installation prior to        Analysis must show that any     Take steps to remove
                                     demonstrate cleanliness         initial use of the              detected target compounds in    contamination
                                     (positive bias) by analyzing    instrument.                     the zero-air challenge sample   attributable to the
                                     humidified zero air;                                            are at response levels that     analytical
                                     performed by connecting the                                     are expected to be <20 pptv     instrumentation by
                                     clean humidified gas sample                                     or not detected.                following the
                                     to the pre concentrator to                                                                      manufacturer's
                                     verify that the analytical                                                                      instructions (e.g.,
                                     instrument and all                                                                              analyzing
                                     connections are sufficiently                                                                    replicates of
                                     clean.                                                                                          humidified clean
                                                                                                                                     gas).

[[Page 43286]]

 
Analytical known-standard           Test to demonstrate that the    At installation prior to        Verifies that all target        Check for cold spots
 challenge for analytical            analytical instrumentation      initial use of the instrument   compounds are detected by the   in transfer line,
 instrumentation.                    (preconcentrator and GC-MS      and with instrument's annual    system, that they respond       gas impurities,
                                     system) is not causing loss     calibration.                    consistently upon repeated      sorbent traps, GC
                                     of compounds (negative bias).                                   injection, and that they        column, system
                                                                                                     exhibit sufficient response     leaks, and/or poor
                                                                                                     to be quantifiable at low       moisture
                                                                                                     concentrations (see Section     management. Consult
                                                                                                     8.2.2 of this method).          instrument
                                                                                                                                     manufacturer for
                                                                                                                                     steps to eliminate
                                                                                                                                     bias, as necessary.
Zero-air challenge of autosamplers  After establishing the ICAL,    Prior to initial use, upon      Each target VOC's               (1) Heat and purge
 associated with analytical          each port of the autosampler    replacement of transfer         concentration must be <20       any lines, and/or
 instrument systems.                 is tested to demonstrate        lines, or after analysis of     pptv or preferably not         (2) Rinse with
                                     cleanliness (positive bias)     potentially contaminating       detected (see Section 8.2.3     deionized water,
                                     by analyzing humidified zero    samples.                        of this method).                dry, and purge any
                                     air; performed by connecting                                                                    lines that fail.
                                     the clean humidified gas
                                     sample to the port to verify
                                     that transfer lines and all
                                     connections are sufficiently
                                     clean.
Known-standard challenge of         After establishing the ICAL,    Prior to initial use and upon   Each target VOC's               (1) Heat and purge
 autosamplers associated with        each port of the autosampler    replacement of transfer         concentration within 15% of theoretical       (2) Rinse with
                                     standard (approximately 100                                     concentration (see Section      deionized water,
                                     to 500 pptv) to demonstrate                                     8.2.3 of this method).          dry, and purge any
                                     that the autosampler is not                                                                     lines that fail.
                                     causing bias (typically loss
                                     of compounds or negative
                                     bias).
Canister leak check...............  Verification that canisters     Prior to initial use and        A pressure change >=0.69 kPa/   (1) Remove from
                                     are leak-free by performing a   annually thereafter.            day (see Section 8.3.2 of       service, and
                                     pressure decay test of a                                        this method).                  (2) Repair canister
                                     canister pressurized to                                                                         connections and/or
                                     approximately 203 kPa                                                                           valve.
                                     absolute (29.4 psia) over the
                                     course of two days.
Canister zero-air verification....  Test of canisters to determine  Initially upon receipt in the   Upon initial analysis after a   (1) Clean and retest
                                     that they are and remain        laboratory and every 18         minimum of 24 hours and after   canisters that fail
                                     acceptably clean (show          months thereafter.              7 days, each target VOC's       the zero-air
                                     acceptably low positive bias)                                   concentration <=20 pptv at      verification.
                                     over the course of 7 days, by                                   152 kPa absolute (22.1 psia).  (2) Remove canisters
                                     filling with humidified zero                                                                    from service that
                                     air (not nitrogen).                                                                             cannot pass the
                                                                                                                                     zero-air
                                                                                                                                     verification after
                                                                                                                                     the cleaning
                                                                                                                                     process.
Known-standard challenge of         Test of canisters to determine  Initially upon receipt in the   Upon initial analysis after a   (1) Clean and retest
 canisters for qualification.        bias by filling with a known    laboratory and every 18         minimum of 24 hours and         canisters that fail
                                     reference standard              months thereafter.              subsequent analysis at 30       the zero-air
                                     (approximately 100 to 500                                       days or typical laboratory      verification.
                                     pptv) prepared in humidified                                    holding time, each target      (2) Remove canisters
                                     zero air (not nitrogen) and                                     VOC's concentration must        from service that
                                     analyzing.                                                      remain within 30%   cannot pass the
                                                                                                     of theoretical concentration    zero-air
                                                                                                     (see Section 8.3.4 of this      verification after
                                                                                                     method).                        the cleaning
                                                                                                                                     process.
Zero-air challenge of sampling      Assessment of positive bias of  Prior to initial field          Analysis must show that the     (1) Take steps to
 devices.                            sampling system by collecting   deployment and every twelve     target compounds in the zero-   remove the
                                     humidified zero air through     months thereafter, following    air challenge sample            contamination
                                     the sampling device/system      maintenance (component          collected through the           attributable to the
                                     and comparing it to the         replacement), or after          sampling unit are not >20       sampling unit
                                     reference sample collected      collection of potentially       pptv higher than the            (e.g., purging with
                                     upstream of the sampling        contaminating samples.          concentration in the            HCF zero air
                                     device/system.                                                  reference sample (see Section   overnight or
                                                                                                     8.1.5 of this method).          longer).
                                                                                                                                    (2) Disassemble and
                                                                                                                                     clean. See Section
                                                                                                                                     8.6 of this method.
Flow control flow check...........  Verification of the mechanical  Prior to and after each field   Flow measurement must           (1) Recalibrate or
                                     flow control device (MFCD)      sampling event                  demonstrate that the MFCD       use a different
                                     flow rate.                                                      flow rate is within 10% of the calibrated     sampling event as
                                                                                                     flow setting.                   appropriate.
                                                                                                                                    (2) Flag any
                                                                                                                                     sample(s) collected
                                                                                                                                     with a failing post-
                                                                                                                                     flow control flow
                                                                                                                                     check.
Known-standard challenge of         Assessment of bias of sampling  Prior to initial field          Each target VOC's               (1) Take steps to
 sampling devices/systems.           system by collecting a known    deployment and at least every   concentration within 15% of concentrations     contamination
                                     (approximately 100 to 500       following maintenance           in the reference sample.        attributable to the
                                     pptv) through the sampling      (component replacement), or                                     sampling unit
                                     device/system and comparing     after collection of                                             (e.g., purging with
                                     it to the reference standard    potentially contaminating                                       HCF zero air
                                     collected upstream of the       samples or damaging sample                                      overnight or
                                     sampling device/system.         matrices that may impact the                                    longer).
                                                                     activity of the flow path                                      (2) Disassemble and
                                                                     surfaces.                                                       clean. See Section
                                                                                                                                     8.6 of this method.
Purge gas check...................  Analysis of canister cleaning   Verified upon initial setup     Each target VOC's               Replace hydrocarbon
                                     purge gas to ensure             and in the event of changes     concentration <20 pptv (see     trap, catalytic
                                     contaminants are acceptably     in gas sourcing or after the    Section 8.4.1 of this           oxidizer,
                                     low.                            replacement of scrubbers such   method).                        contaminated
                                                                     as hydrocarbon traps and                                        tubing, etc.
                                                                     moisture traps, or following
                                                                     maintenance of zero-air
                                                                     generator.

[[Page 43287]]

 
Canister cleaning blank check.....  Analysis of a sample of         Every canister from each batch  Upon analysis 24 hours after    (1) Reclean
                                     humidified diluent gas in a     of cleaned canisters.           filling, each target VOC's      canister, and/or
                                     canister after cleaning to                                      concentration must meet the    (2) Disassemble and
                                     ensure acceptably low levels                                    canister blank acceptance       clean the
                                     of VOCs in the cleaned                                          criterion .(i.e., <=20 pptv     components
                                     canisters.                                                      at 152 kPa absolute, 22.1       according to
                                                                                                     psia) (see Section 8.5 of       Section 8.6 of this
                                                                                                     this method).                   method.
Holding time......................  Duration from end of sample     Each field-collected or         <=8 days                        (1) Reprepare any
                                     collection or canister          laboratory QC (standard or                                      lab standard or
                                     preparation to analysis.        blank) canister.                                                blank.
                                                                                                                                    (2) Flag the results
                                                                                                                                     of any sample
                                                                                                                                     analyzed outside of
                                                                                                                                     holding time.
Bromofluorobenzene instrument tune  Injection of 1 to 2 nanograms   Prior to ICAL and prior to      Abundance criteria for BFB      (1) Retune, and/or
 performance check.                  (ng) BFB for tune               analysis of each day's          listed in Table 5 in Section   (2) Perform
                                     verification of quadrupole or   analytical batch.               17 of this method (see          maintenance.
                                     ion trap MS detector.                                           Section 10.7.2 of this
                                                                                                     method)
Retention time (RT)...............  RT of each IS and target        All qualitatively identified    IS compounds and target oHAP    Flag data for
                                     compound.                       compounds and internal          within 2 seconds    possible
                                                                     standards.                      of most recent calibration      invalidation.
                                                                                                     check.
Samples--internal standards (IS)..  Deuterated or other compounds   All laboratory QC samples, and  Area response for each IS       Flag data for
                                     not typically found in          field-collected samples.        compound must be within 30% of the average        invalidation.
                                     samples to monitor instrument                                   response as determined from
                                     response and assess matrix                                      the most recent calibration
                                     effects.                                                        check.
Initial calibration (ICAL)........  Analysis of a minimum of five   Before sample analysis,         Average Relative Response       (1) Repeat
                                     calibration levels covering     following failed BFB tune       Factor (RRF) <=30% RSD and      calibration
                                     approximately 20 to 5000        check (as applicable), failed   each calibration level within   standard analysis.
                                     pptv.                           IS criteria, or failed CCV      30% of             (2) Repeat linearity
                                                                     criteria; annually, or when     theoretical concentration;      check.
                                                                     changes/maintenance to the      Relative Retention Times       (3) Prepare new
                                                                     instrument affect calibration   (RRTs) for target peaks         calibration
                                                                     response.                       within 0.06 units from mean     standards as
                                                                                                     RRT.                            necessary and
                                                                                                                                     repeat analysis.
Second source calibration           Analysis of a secondary source  Immediately after each ICAL.    Measured concentrations of      (1) Repeat SSCV
 verification (SSCV).                standard in the lower third                                     VOCs must be within 30% of theoretical       (2) Reprepare and
                                     verify ICAL accuracy for each                                   concentration (see Section      reanalyze SSCV
                                     target analyte.                                                 9.1 of this method).            standard.
Continuing calibration              Analysis of a known standard    Prior to analyzing samples in   Measured concentrations of      (1) Repeat CCV
 verification (CCV).                 in the lower third of the       an analytical sequence and at   VOCs within 30%     analysis.
                                     calibration curve to verify     the end of a sequence, unless   of theoretical concentration   (2) Repeat ICAL.
                                     ongoing instrument              the sequence begins with an     (see Section 9.2 of this
                                     calibration for each target     ICAL; and after every 10        method).
                                     analyte.                        sample injections.
Instrument blank (IB).............  Analysis of an injection where  Prior to ICAL and at the        Each target VOC's               (1) Repeat IB
                                     no sample or standard is        beginning of an analytical      concentration must be <20       analysis.
                                     introduced to the               sequence.                       pptv (see Section 9.3.1 of     (2) Bakeout
                                     preconcentrator to                                              this method).                   preconcentrator
                                     preliminarily demonstrate the                                                                   system and repeat
                                     carrier gas and instrument                                                                      IB analysis.
                                     are sufficiently clean to                                                                      (3) Replace
                                     begin analysis.                                                                                 contaminated tubing/
                                                                                                                                     traps as needed.
Method blank (MB).................  Canister filled with clean,     Prior to and following the      This must demonstrate           (1) Repeat analysis.
                                     humidified diluent gas;         ICAL and daily following the    acceptably low carryover in    (2) Reprepare the MB
                                     indicates that target VOCs      IB/BFB and prior to the         the analytical system prior     canister and
                                     and potential interferences     initial daily CCV/SSCV.         to analysis of samples; each    reanalyze.
                                     are at acceptably low levels                                    target VOC's concentration     (3) Check the system
                                     in the system as a whole; the                                   must be <20 pptv (see Section   for leaks.
                                     MB is to help assess overall                                    9.3.2 of this method).
                                     quality of the data.
Calibration blank (CB)............  Canister filled with clean,     Prepare one CB with each set    CB must be sufficiently clean   (1) Reanalyze CB.
                                     humidified diluent gas          of calibration standard         such that little or no         (2) Reprepare CB and
                                     sourced through the standard    canisters and analyze with      positive bias is imparted to    ICAL canister
                                     preparation dilution system;    each ICAL                       the calibration (see Section    standards.
                                     indicates that diluent gas                                      9.3.3 of this method).
                                     and dilution apparatus do not
                                     contribute target VOCs,
                                     imparting a positive bias to
                                     the ICAL
Method precision..................  Duplicate samples: precision    Applicable to the collection    Precision <=30% RPD of target   (1) Check for
                                     is determined from the          of samples: one per sampling    VOCs in the compared samples    preconcentrator
                                     analyzed concentrations of      day.                            when both measurements are >=   volume measurement
                                     collocated samples.                                             fivefold MDL (see Section 9.4   error.
                                                                                                     of this method).               (2) Reanalyze
                                                                                                                                     primary sample and
                                                                                                                                     collocated
                                                                                                                                     duplicate.
                                                                                                                                    (3) Flag data for
                                                                                                                                     possible
                                                                                                                                     invalidation.
Instrument precision..............  Precision is determined from    One replicate analysis to be    Precision <=25% RPD for target  (1) Check for
                                     repeated analyses of a sample   performed with each sampling    VOCs when both measurements     preconcentrator
                                     from a single canister;         day.                            are >= fivefold MDL (see        volume measurement
                                     replicate analyses are used                                     Section 9.4 of this method).    error.
                                     to determine precision of the                                                                  (2) Reanalyze
                                     analysis processes and do not                                                                   primary sample and
                                     provide information on                                                                          collocated
                                     sampling precision.                                                                             duplicate.
                                                                                                                                    (3) Flag data for
                                                                                                                                     possible
                                                                                                                                     invalidation.

[[Page 43288]]

 
Preconcentrator leak check........  Pressurize or evacuate the      Each canister connected to the  <3.4 kPa (0.5 psi) change per   Check the tightness
                                     canister connection to verify   instrument prior to analysis.   minute or as recommended by     of all fittings and
                                     as leak-free.                                                   the manufacturer (see Section   recheck.
                                                                                                     11.4.2 of this method).
--------------------------------------------------------------------------------------------------------------------------------------------------------

10.0 Calibration and Standardization

    10.1 Humidification of Canisters.
    10.1.1 Calculate the volume of water you must add to standard and 
blank canisters to achieve 40 to 50% RH at ambient laboratory 
temperature. (See Equation 6 in Section 12 of this method).
    10.1.2 Use a bubbler or impinger within the dilution gas stream, 
add water to the canister, or use a combination of these two methods to 
add the calculated volume of deionized water to the canister necessary 
to achieve internal RH of approximately 40 to 50% at ambient laboratory 
temperature. For direct injection of water into a canister with a 
syringe, install a high-pressure PTFE-sealed septum on the canister. 
For canisters that are to be connected to a gas source for 
pressurization via a dynamic or static dilution system, you can add the 
deionized water to the valve opening of the evacuated canister prior to 
connecting to the dilution system. Do not add water to the canister 
using a syringe via rubber septum or other materials that may introduce 
target or interfering compounds.
    10.2 Dynamic Dilution.
    10.2.1 Gas Dilution System. The gas dilution system must produce 
calibration gases whose measured concentration values are within 2% of the predicted values. The predicted values are calculated 
based on the certified concentration of the supply gas (Protocol gases, 
when available, are recommended for their accuracy) and the gas flow 
rates (or dilution ratios) through the gas dilution system.
    10.2.2 The gas dilution system must be calibrated and verified per 
Section 6.10.1 of this method.
    10.2.3 Standards Preparation by Dynamic Dilution.
    10.2.3.1 Prior to use, power on the dynamic dilution system and 
allow the diluent and stock gases to flow through the respective MFC at 
operating flow rates. Allow gases to flow for at least the minimum time 
used during the yearly bias check in Section 6.10.1.3 of this method, 
to ensure the concentrations of the oHAPs in the blended gas are stable 
prior to transferring to the humidified canister (or directly to the 
preconcentrator).
    10.2.3.2 You must prepare humidified (40 to 50% RH) standards in 
canisters from low concentration to high concentration. When changing 
stock gas flow rate(s) to prepare a different concentration, allow the 
calibration gas sufficient time to flow through the system prior to 
preparation of the working calibration canister (or delivering the 
working standard directly to the preconcentrator).
    10.2.3.3 The final pressure of the calibration standard canister 
must not exceed the maximum pressure permitted by the preconcentrator.
    10.2.2.4 Calculate the final concentration of the diluted standard 
using Equation 7 in Section 12 of this method.
    10.3 Static Dilution.
    10.3.1 Static Gas Dilution System. The gas dilution system shall 
produce calibration gases whose measured values are within 2% of the predicted values. The predicted values are calculated 
based on the certified concentration of the supply gases (Protocol 
gases, when available, are recommended for their accuracy) and their 
partial pressure measurements (or dilution ratios) in the prepared 
standard canister.
    10.3.2 Static Dilution by Addition of Partial Pressures into a 
Canister.
    10.3.2.1 Connect a pressure transducer or gauge to an evacuated 
canister to monitor the canister pressure as you add gases. The 
pressure transducer or gauge must meet the requirements in Section 6.5 
of this method.
    10.3.2.2 Add stock and diluent gases separately through a manifold 
or by direct connection of the gas to the standard canister or vessel.
    10.3.2.3 Measure the canister pressure before and after standard 
and diluent gases are bled into the canister and input these pressures 
into the calculation of the dilution factor and final concentrations.
    10.3.2.4 Calculate the final concentration of each target compound 
in the diluted standard using Equation 8 in Section 12 of this method.
    10.4 Storage of Standards. Standards prepared in canisters at 
ambient laboratory conditions must be stored in locations that are free 
of potential contaminants for up to 7 days.
    10.5 Pre-Concentration System Operation. Condition preconcentrator 
traps when first installed to eliminate contaminants that act as 
interferences or chromatographic artifacts, per manufacturer 
recommendation. After the recommended conditioning procedure is 
completed, analyze the IBs and MBs to verify the preconcentrator system 
meets the method criteria.

    Note:  For preconcentrator traps that contain multiple types of 
sorbent beds, the oven temperature must not exceed the lowest 
conditioning temperature of the sorbents contained in the trap.

    10.6 GC-MS System. Optimize GC conditions for compound separation 
and sensitivity as indicated by baseline separation for the targeted 
compounds by establishing GC carrier gas flow rates, oven temperature 
program, and instrument run time based on the manufacturer's 
recommendations and customize, as needed, to separate the desired 
target oHAPs.
    10.7 MS Tuning/Optimizing and Verification.
    10.7.1 General. Tune/optimize the MS (quadrupole, ion trap, or TOF 
MS) to demonstrate acceptable performance across the selected ion mass 
range according to the manufacturer's specifications upon initial 
installation of the instrument and following significant preventive 
maintenance or repair activities that impact the performance of the GC-
MS system (e.g., cleaning the ion source or analyzer; trimming or 
replacing the capillary column; and adjusting MS tune or optimization 
parameters).
    10.7.2 BFB Tuning Check. Before the ICAL and at least once during 
every 24-hour period of analyzing samples, blanks, or calibration 
standards thereafter, you must conduct a BFB tuning check for linear 
quadrupole or ion trap MS instruments. The BFB tuning check may be 
combined with the IB.
    10.7.2.1 Introduce 1 to 2 ng of BFB into the preconcentrator and 
analyze the standard using the preconcentrator parameters established 
and used for the analysis of calibration standards, QC samples, and 
field samples. You must also use the method integration and analysis 
parameters employed for

[[Page 43289]]

routine analysis of standards, QC samples, and field samples.
    10.7.2.2 The BFB tuning check must show that the GC-MS system meets 
the mass spectral ion abundance criteria listed in Table 2 in Section 
17 of this method for the target compounds before you can use the 
system for any analysis. If the GC-MS system cannot meet the BFB tuning 
criteria, adjust the tuning of the MS or take corrective actions. You 
must not use this system until the abundance criteria has been met.
    10.8 Internal Standards and Calibration.
    Method users must meet acceptance criteria for the calibration and 
QC listed in the following section for the suite of target compounds.
    10.8.1 Selection and Use of Internal Standards (IS).
    10.8.1.1 Select IS compound(s) to be used for oHAP analysis. At a 
minimum, you must use a single IS compound. IS compounds must have 
similar retention times to the compounds being detected. Typical IS 
compounds include bromochloromethane; 1,4-difluorobenzene; 
chlorobenzene-d5; 1,2-dichloroethane-d4; hexane-d14; toluene-d8; and 
1,2-dichlorobenzene-d4.
    10.8.1.2 If using purchased IS stock gases, evaluate the IS upon 
receipt for the presence of contaminants that may interfere with the 
quantitation of target compounds by analyzing increasing volumes of the 
IS (e.g., 25, 50, 100, 250 milliliters [mL]) and examining the results 
for compound contaminants whose responses increase proportionally with 
the increasing volume of IS analyzed. Do not use IS gas standards that 
fail the MB acceptance criteria.
    10.8.1.3 You must add the IS through a dedicated non-sample port in 
the preconcentrator at the same concentration for each injection (e.g., 
standard, sample, blank) to monitor instrument sensitivity and assess 
potential matrix effects. Choose the concentration of IS added to each 
injection such that the peak area response for the IS compound 
approximates the area responses for target compounds in the lower half 
of the calibration curve range, but that minimally provides a peak that 
is on scale and does not exceed the area response of the highest 
calibration standard.
    10.8.1.4 Internal Standard Retention Time (RT). Each IS compound in 
each sample injection must be within 2 seconds of the RT 
for each IS compound in the most recent calibration.
    10.8.1.5 Internal Standard Response. The area response for each IS 
compound in each injection (e.g., calibration standard, field sample, 
blank, CCV) must be within 30% of the mean area response of 
the IS compound determined from the ICAL determined using Equation 10 
in Section 12 of this method or most recent calibration check, 
whichever is most appropriate.
    10.8.1.6 Choose the quantitation ion for each IS compound as the 
most abundant ion (base peak) unless there is a spectral interference 
from a coeluting or nearby compound or interference that impacts the 
quantitation of the base peak. In such cases, select another abundant 
ion that is distinguishable from the other compounds for quantitation.
    10.8.1.7 You must invalidate then reanalyze any samples for which 
the IS area response differs by more than 30% from the mean IS area 
response.
    10.8.2 Establishing Calibration. Calibrate the GC-MS initially, 
annually, whenever CCV standards exceed acceptance criteria, or when 
the system is out of control as indicated by IS responses. Prior to 
calibration, analyze a sufficient number of humidified (40 to 50% RH) 
HCF zero air blanks or humidified check standards to verify that 
instrument sensitivity is stable, as indicated by IS response.
    10.8.2.1 Preparation for Calibration.
    10.8.2.1.1 Prepare the calibration curve by preparing standards 
that bracket the expected concentration levels at the sampling 
location(s).
    10.8.2.1.2 You must include at least five levels in the ICAL to 
approximate concentrations of target oHAPs expected at the deployment 
location(s), including one level within a factor of five of the 
detection limits of the compounds of interest, and another level within 
10% of the compound specific action-level, as defined in the applicable 
standard.

    Note:  To establish the calibration curve, the theoretical 
concentrations of the working calibration standards must be 
calculated using the certified concentration from the gas vendor or 
neat standard provider. Certificates of analysis for stock standard 
gas mixtures typically include both a nominal (or ``requested'') 
concentration (e.g., 100 ppbv) for each analyte and a certified 
concentration (e.g., 108 ppbv), which should be within a specified 
tolerance (e.g., 10%). These tolerances may 
permit the certified concentration to differ from the nominal 
concentration by 10% to 20%, resulting in final theoretical 
concentration errors for the working-level standards when the 
nominal concentration is input into standard concentration 
calculations instead of the certified concentration. Calibration 
standards prepared with neat materials must account for the standard 
purity when calculating the working standard concentrations.

    10.8.2.2 Calibration Curve.
    10.8.2.2.1 Following analysis of all calibration standards, prepare 
a calibration curve for each target analyte by determining the relative 
response factor (RRF) of each concentration level. Following data 
acquisition for the calibration standards, calculate the RRF of each 
target compound in each calibration level using Equation 10 in Section 
12 of this method.
    10.8.2.2.2 Choose the quantitation ion for each target compound as 
the most abundant ion (base peak) unless there is a spectral 
interference from a coeluting or nearby compound or interference that 
impacts the quantitation of the base peak. In such cases, select 
another abundant ion that is distinguishable from the other compounds 
for quantitation.
    10.8.2.2.3 The %RSD of the RRFs of the ICAL levels for each target 
compound using Equation 17 in Section 12. The %RSD must be <=30% for 
the ICAL to be considered acceptable.
    10.8.2.2.4 The calculated concentration for each target compound(s) 
at each calibration level must be within 30% of the 
theoretical concentration when quantitated against the resulting 
calibration curve.

11.0 Analytical Procedures

    11.1 Measurement of Canister Receipt Pressure.
    11.1.1 Upon receipt at the laboratory, review the sample collection 
information documented on the field data page and/or COC form(s) for 
completeness and accuracy. Compare the canister label with the sample 
collection data sheet and verify that the canister and sample IDs are 
correct.
    11.1.2 Measure and record the canister pressure using a calibrated 
vacuum/pressure gauge or transducer. The measured canister absolute 
pressure must be within 3.5 kPa (1 in. Hg or 0.5 psi) of 
that measured upon collection in the field. Pressure differences 
exceeding this criterion indicate the canister has leaked and you must 
flag the results as invalid.
    11.2 Dilution of Canister Samples. A canister must be pressurized 
to provide sufficient pressure for removing an aliquot from the 
canister for analysis. Pressurize the canister with diluent gas to a 
pressure less than or equal to the final pressure of the standard gas 
canisters.

    Note:  Minimum sample pressures will depend on the size of the 
canister and the capability of the preconcentrator to remove the 
desired aliquot of the sample and will be indicated by the 
instrument manufacturer.

    11.2.2 Measure the canister pressure using a calibrated vacuum/
pressure gauge or pressure transducer just prior to dilution and 
immediately following

[[Page 43290]]

dilution and calculate the canister dilution correction factor (DFC) 
from the two absolute pressure readings (see Equation 12 in Section 12 
of this method).
    11.2.3 You must allow diluted canisters to equilibrate for a 
minimum of 12 hours before analysis.
    11.3 Sample Preconcentration. Draw a measured aliquot of the whole 
air sample (typically 100 to 1000 mL) from the sample canister by 
vacuum through a preconcentrator to minimize the moisture and bulk 
atmospheric gases (e.g., oxygen, nitrogen, argon, and carbon dioxide) 
from the sample aliquot prior to introduction of the target compounds 
to the GC.

    Note:  Preconcentrator instrument manufacturers will typically 
indicate the optimum factory default settings for the sample aliquot 
volume, trapping time, trapping temperature, gas flows, and 
additional preconcentration parameters. Adjust each of these 
variables as needed for the target compounds.

    11.4 Sample Analysis. You must analyze samples using the same 
acquisition methods you used for establishing calibration (i.e., 
preconcentrator operation parameters, GC oven program, MS parameters, 
and integration methods). Field-collected samples and QC samples must 
be at ambient laboratory temperature for analysis. You must use 
approximately the same sample aliquot volume for all samples unless 
dilution is required. Adjustment of this sample aliquot volume requires 
adjustment of a dilution factor to account for the difference in 
relative analyzed volume, as discussed in Section 11.4.4 of this 
method.
    11.4.1 Leak Check of Preconcentrator Connections.
    11.4.1.1 Prior to beginning an analytical sequence, including an 
ICAL sequence, verify each canister connection as leak-free through the 
preconcentrator.
    11.4.1.2 During the leak check, connect canisters to the 
autosampler or sample introduction lines and maintain the canister 
valves in the closed position.
    11.4.1.3 Evacuate each port of the autosampler or sample 
introduction line and monitor for a change in pressure for 1 minute. 
The pressure must not change by more than 0.5 psig/minute.
    11.4.1.4 If a sample line fails the leak check, implement 
corrective actions (e.g., rechecking the tightness of all fittings) and 
then retest. Do not perform analysis using any canister connection that 
does not pass the leak check.
    11.4.1.5 Following the successful leak check, evacuate all 
autosampler ports or sample introduction lines, open the canister 
valves, and document the leak check results in the analysis records.
    11.4.2 Sample Introduction.
    11.4.2.1 Prior to each sample analysis sequence, you must connect 
each sample canister to the preconcentration unit through a port and 
verify each canister as having a leak-free connection.
    11.4.2.2 Accurately measure the sample aliquot volume for analysis 
by metering the sample with an MFC or with the combination of a fixed-
volume vessel and a pressure transducer. Sample introduction volume 
measurements must be made by the same device as the calibration 
standards to ensure that analyzed volumes of samples and standards are 
consistent.
    11.4.3 Analysis of Field Samples. Perform the following steps for 
readying the system and performing the GC-MS analytical sequence. Once 
these checks meet criteria (summarized in Table 9-1 of this method), 
verify the instrument calibration by analysis of a CCV and begin sample 
analysis.
    11.4.3.1 Perform an air/water check of the MS prior to any analyses 
to ensure that the system is acceptably leak-free.
    11.4.3.2 Conduct a thorough system bakeout per the manufacturer's 
instructions for the preconcentrator and ramp the GC column 
temperature.
    11.4.3.3 Analyze a preliminary IB or perform the BFB instrument 
tuning check.
    11.4.3.4 Analyze a laboratory MB to demonstrate that the system is 
acceptably clean and that each target compound is <20 pptv or 
undetected (whichever is more stringent) per compound of interest.
    11.4.3.5 Analyze a CCV to verify the instrument calibration.
    11.4.3.6 Analyze field samples and additional CCV standards (every 
10 samples) and MBs to complete the sequence, ending with a CCV, as 
discussed in Section 9.2 of this method.
    11.4.4 Sample Dilution. If the on-column concentration of any 
compound in any sample exceeds the calibration range, you must dilute 
the sample for reanalysis by either reducing the sample aliquot volume 
for an effective dilution or adding diluent gas to the sample canister 
to physically dilute the sample.
    11.5 Compound Identification.
    11.5.1 After completing data acquisition, examine each 
chromatogram. Chromatographic peaks for the target compounds must be 
appropriately resolved, and integration must not include peak shoulders 
or inflections indicative of a coelution. If a peak has not been 
integrated properly, you may choose to manually integrate the peak. If 
a peak has been manually integrated, you must flag the results and 
report how and why the peak was manually integrated.

    Note:  Deconvolution techniques may be available to the operator 
to help resolve compound coelutions, depending on the particular 
instrument and chromatography software package that is in use.

    11.5.2 Identify target compounds qualitatively based on their RT 
and the relative abundance of their characteristic ions from the MS by 
satisfying the following four criteria. If any of the four criteria are 
not met, the compound cannot be positively identified.

    Note:  Target compounds detected below the lowest calibration 
standard are estimated and may not be able to satisfy all four 
criteria.

    11.5.2.1 The RT of the compound must be within the RT window of 
2 seconds of the most recent calibration check.
    11.5.2.2 The relative abundance ratio of qualifier ion response to 
target ion response for at least one qualifier ion must be within 
30% of the average relative abundance ratio from the ICAL.
    11.5.2.3 The S:N ratio of the target and qualifier ions must be 
>3:1.
    11.5.2.4 The target and qualifier ion peaks must be co-maximized 
(i.e., peak apexes within one scan of each other).
    11.6 Compound Quantitation. After determining the peak areas, 
initiate the quantitation process using the software package of choice 
to provide quantitative results compound using the RRF of the daily CCV 
for each target compound to quantitate the samples for the analytical 
batch.
    11.6.2 Dilution Correction Factors.
    11.6.2.1 Calculate an instrument dilution correction factor (DFI) 
if you analyzed an aliquot from the sample canister that is different 
from the typical analysis volume (as described in Section 11.4.4 of 
this method for performing effective dilution) using Equation 14 in 
Section 12 of this method.
    11.6.2.2 Use Equation 15 in Section 12 of this method to determine 
the final concentration of each target compound in air by multiplying 
the instrument-detected concentration by the dilution factor from 
sample pressurization (DFC) (see Section 11.2 of this method) and the 
DFI.

    Note:  The MDL reported with the final concentration data will 
be corrected by multiplying the MDL by the DFC and DFI applied to 
the sample concentrations.


[[Page 43291]]



12.0 Data Analysis and Calculations

    12.1 Canister Final Air/Nitrogen Volume (Vcalc).
    [GRAPHIC] [TIFF OMITTED] TR16MY24.068
    
Where:

Pclean = absolute pressure of canister cleaning batch 
blank, kPa absolute.
Pstd = 152.3 kPa absolute, standard atmospheric pressure.
Vcan = volume of the canister (mL) at standard conditions 
(101.3 kPa absolute and 25 [deg]C).

    12.2 Acceptable Blank Canister Concentration Criterion 
(Cacc).
[GRAPHIC] [TIFF OMITTED] TR16MY24.069

Where:

Cacc = acceptance limit concentration at measured 
canister pressure (pptv).
Catm = 20 pptv, acceptance limit concentration at 
standard atmospheric pressure.
Pref = 152 kPa absolute, reference pressure.
Pclean = absolute pressure of cleaned canister, kPa 
absolute.

    12.3 Percent Difference of the Measured Concentration of Each 
Target Compound in the CCV Standard (%DCCV) from the 
Theoretical Concentration.
[GRAPHIC] [TIFF OMITTED] TR16MY24.070

Where:

%DCCV = percent difference of the measured concentration 
of each target compound in the CCV standard from the theoretical 
concentration.
CCCV = measured concentration of the CCV for each target 
compound (pptv).
Ctheoretical = theoretical concentration of the CCV for 
each target compound (pptv).

    12.4 Percent Recovery (%RecoveryCCV).
    [GRAPHIC] [TIFF OMITTED] TR16MY24.071
    
Where:

%RecoveryCCV = percent recovery of measured versus actual 
concentration.
    Ctheoretical = theoretical concentration of the CCV 
for each target compound (pptv).

    12.5 Relative Percent Difference (RPD).
    [GRAPHIC] [TIFF OMITTED] TR16MY24.072
    
Where:

RPD = relative percent difference.
X1 = target compound concentration measured in first 
measurement of the precision pair (pptv).
X2 = target compound concentration measured in second 
measurement of the precision pair (pptv).

    12.6 Water Volume to Add to Canister (Vw).
    [GRAPHIC] [TIFF OMITTED] TR16MY24.073
    
Where:

Dsat = saturation vapor density of water (mg/[mu]L) at 
ambient laboratory temperature (refer to Table 3 in Section 17 of 
this method).
RHd = desired RH level expressed as a decimal.
Vc = nominal internal volume of canister (L).
Pc = final absolute canister pressure (kPa absolute).
Ps = standard ambient pressure (101.3 kPa absolute).
Dw = density of water (1 mg/[mu]L).

    Note:  The equation assumes the density of water to be 1 g/mL 
and that 100% of the added water to the canister is in the gas 
phase. The equation does not correct the density of water for the 
ambient temperature.


[[Page 43292]]


    12.7 Final Concentration of the Diluted Standard (Cf)--
Dynamic Dilution.
[GRAPHIC] [TIFF OMITTED] TR16MY24.074

Where:

Cf = final concentration of the diluted standard.
Cs = certified concentration of stock standard (pptv).
Fd = flow of diluent gas (mL/min).
Fs = flow of stock standard (mL/min).

    Note:  If you combine multiple gas standards for dilution, the 
equation denominator is the sum of all gas flows combined for 
preparing the dilution.

    12.8 Final Concentration of the Diluted Standard (Cf)--
Static Dilution.
[GRAPHIC] [TIFF OMITTED] TR16MY24.075

Where:

Cs = certified concentration of stock standard (pptv).
Psa = absolute pressure of canister after adding standard 
gas (kPa).
Psb = absolute pressure of canister before adding 
standard gas (kPa).
Pf = final absolute pressure of canister after adding 
standard and diluent gases (kPa).

    12.9 Average Retention Time (RT).
    [GRAPHIC] [TIFF OMITTED] TR16MY24.076
    
Where:

RT = average RT for the IS compound (min).
RTi = RT for the IS compound for each calibration level 
(min).
n = number of units used to generate a sum.

    12.10 Relative Response Factor (RRF).
    [GRAPHIC] [TIFF OMITTED] TR16MY24.077
    
Where:

As = peak area for quantitation ion of the target 
compound.
AIS = peak area for quantitation ion of the assigned IS 
compound.
Cs = certified concentration of stock standard (pptv).
CIS = concentration of the assigned IS compound (pptv).

    12.11 Average Area Response for the Given IS Compound (Y).
    [GRAPHIC] [TIFF OMITTED] TR16MY24.078
    
Where:

Yi = area response for an IS compound at calibration 
concentration i.
n = number of units used to generate a sum.

    12.12 Dilution factor for sample pressurization (DFC).
    [GRAPHIC] [TIFF OMITTED] TR16MY24.079
    
Where:

Pd = pressure of the canister following dilution (kPa).
Pi = absolute pressure of the canister immediately 
preceding dilution (kPa).

    12.13 Instrument-Detected Analyte Concentration (CD) in 
pptv.
[GRAPHIC] [TIFF OMITTED] TR16MY24.080

Where:

CD = instrument-detected analyte concentration (pptv).
AIS = peak area for quantitation ion of the assigned IS 
compound.

    12.14 Instrument Dilution Correction Factor (DFI).

[[Page 43293]]

[GRAPHIC] [TIFF OMITTED] TR16MY24.081

Where:

Vnom = The laboratory's typical canister sample injection 
volume (mL).
Vinj = The actual volume of any given sample injection 
(mL).

    12.15 Concentration of the Target Compound in Air (CF).

CF = CD [middot] DFI [middot] DFC Eq. 15

Where:

CD = measured concentration of the target compound in the 
canister as analyzed sample.

    12.16 Standard Deviation of the Response Factors (SDRF).
    [GRAPHIC] [TIFF OMITTED] TR16MY24.082
    
    12.17 Percent Relative Deviation (%RSD).

%RSD = SDRRF / RRF x 100 Eq. 17

13.0 Method Performance

    Table 9-1 of this method lists the QC parameters and performance 
specifications for this method. The method performance will be 
determined by the specific performance of each specific target 
compound, laboratory, and the associated equipment.

14.0 Pollution Prevention

    [Reserved].

15.0 Waste Management

    [Reserved].

16.0 References

1. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume II, Ambient Air Quality Monitoring Program, U.S. 
Environmental Protection Agency, EPA-454/B-17-001, January 2017.
2. Technical Assistance Document for the National Air Toxics Trends 
Stations Program, Revision 4, U.S. Environmental Protection Agency, 
July 2022.
3. Clean Air Act Amendments of 1990, U.S. Congress, Washington, DC, 
November 1990.
4. Method D1356, Standard Terminology Relating to Sampling and 
Analysis of Atmospheres.
5. Method E355-96, Standard Practice for Gas Chromatography Terms 
and Relationships.
6. Method D5466, Standard Test Method for Determination of Volatile 
Organic Compounds in Atmospheres (Canister Sampling Methodology).
7. Agilent Technologies, Inc. (2017, July 11). Innovative Cryogen-
Free Ambient Air Monitoring in Compliance with US EPA Method TO-15. 
Application Note 081, 5991-2829EN. Available at https://www.agilent.com/cs/library/applications/5991-2829EN.pdf (accessed 
September 21, 2019).
8. ASTM International. (2014). Active Standard ASTM E2655-14: 
Standard Guide for Reporting Uncertainty of Test Results and Use of 
the Term Measurement Uncertainty in ASTM Test Methods. West 
Conshohocken, PA: ASTM International. doi: 10.1520/E2655-14.
9. Boyd, R.K., Basic, C., & Bethem, R.A. (2008). Trace Quantitative 
Analysis by Mass Spectrometry, Figure 6.7, p. 260. Hoboken, NJ: John 
Wiley and Sons.
10. Brown, J. (2013, October 22). Choosing the Right Adsorbent for 
your Thermal Desorption Gas Chromatography Applications. Presented 
at the Separation Science Webinar for Supelco. Available at https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Supelco/Posters/1/Adsorbent-Selection-TD-GC-Apps.pdf (accessed September 21, 2019).
11. Code of Federal Regulations, 40 CFR part 58 Appendices D and E, 
Network Design Criteria for Ambient Air Quality Monitoring. 
Available at https://www.govinfo.gov/app/details/CFR-2012-title40-vol6/CFR-2012-title40-vol6-part58-appD (accessed September 22, 
2019).
12. Code of Federal Regulations, 40 CFR part 136 Appendix B, 
Definition and Procedure for the Determination of the Method 
Detection Limit, Revision 2. Available at https://www.govinfo.gov/app/search/%7B%22query%22%3A%2240%20CFR%20Part%20136%20Appendix%20B%2C%20Revision%202%22%2C%22offset%22%3A0%7D (accessed September 23, 2019).
13. Code of Federal Regulations, 40 CFR 173.306 (g), Limited 
quantities of compressed gases. Available at https://www.govinfo.gov/app/search/%7B%22query%22%3A%2249%20CFR%20%C2%A7173.306%20(g)%22%2C%22offset%22%
3A0%7D (accessed September 23, 2019).
14. Coutant, R.W. (1992). Theoretical Evaluation of the Stability of 
Volatile Organic Chemicals and Polar Volatile Organic Chemicals in 
Canisters. Report EPA/600/R-92/055 prepared under contract 68-DO-
0007 for U.S. EPA by Battelle, Columbus, OH.
15. Entech Instruments. (2015, August 25). 3-Stage Preconcentration: 
Why 3-Stage Preconcentration is Superior for TO-14A and TO-15 Air 
Methods. Available at http://www.entechinst.com/3-stage-preconcentration-is-superior-for-to-14a-and-to-15-air-methods/# 
(accessed September 21, 2019).
16. Herrington, J.S. (2013, August 5). TO-15 Canister Relative 
Humidity: Part II (Examples and Calculations) [Blog post]. Available 
at https://blog.restek.com/?p=7766 (accessed September 21, 2019).
17. Keith, L.H. (1991). Environmental Sampling and Analysis: A 
Practical Guide. Boca Raton, FL: CRC Press, pp. 93-119.
18. Kelly T.J., & Holdren, M.W. (1995). Applicability of canisters 
for sample storage in the determination of hazardous air pollutants. 
Atmospheric Environment, 29(19), 2595-2608. doi: 10.1016/1352-
2310(95)00192-2.
19. McClenny, W.A., Schmidt, S.M., & Kronmiller, K.G. (1999). 
Variation of the relative humidity of air released from canisters 
after ambient sampling. Journal of the Air & Waste Management 
Association, 49(1), 64-69. doi:10.1080/10473289.1999.10463774.
20. Nave, C.R. (2017). Relative Humidity. HyperPhysics website, 
Department of Physics and Astronomy, Georgia State University, 
Atlanta, GA. Available at http://hyperphysics.phy-astr.gsu.edu/hbase/Kinetic/relhum.html#c3 (accessed September 21, 2019).
21. Ochiai, N., Daishima, S., & Cardin, D.B. (2003). Long-term 
measurement of volatile organic compounds in ambient air by 
canister-based one-week sampling method. Journal of Environmental 
Monitoring, 5(6), 997-1003. doi:10.1039/b307777m.
22. Ochiai, N., Tsuji, A., Nakamura, N., Daishima, S., & Cardin, 
D.B. (2002). Stabilities of 58 volatile organic compounds in fused-
silica-lined and SUMMA polished canisters under various humidified 
conditions. Journal of Environmental Monitoring, 4(6), 879-889.
23. Restek. (2010). A Guide to Whole Air Canister Sampling: 
Equipment Needed and Practical Techniques for Collecting Air 
Samples. Technical Guide. Literature Catalog # EVTG1073A. Available 
at http://www.restek.com/pdfs/EVTG1073A.pdf (accessed September 21, 
2019).
24. U.S. Environmental Protection Agency (EPA). (2017). Quality 
Assurance Handbook for Air Pollution Measurement Systems, Volume II, 
Ambient Air Quality Monitoring Program, EPA-454/B-17-001. Research 
Triangle Park, NC: EPA Office of Air

[[Page 43294]]

Quality Planning and Standards, Air Quality Assessment Division. 
Available at https://www3.epa.gov/ttnamti1/files/ambient/pm25/qa/Final%20Handbook%20Document%201_17.pdf (accessed September 23, 
2019).
25. U.S. Environmental Protection Agency (EPA). (2016a). Definition 
and Procedure for the Determination of the Method Detection Limit, 
Revision 2. U.S. EPA Office of Water, EPA 821-R-16-006. Available at 
https://www.epa.gov/sites/production/files/2016-12/documents/mdl-procedure_rev2_12-13-2016.pdf (accessed September 21, 2019).
26. U.S. Environmental Protection Agency (EPA). (2016b). EPA NATTS 
Proficiency Testing Results Calendar Year 2016 Quarter 1--Referee 
Results from EPA Region V. Available from U.S. EPA, Office of Air 
Quality Planning and Standards (OAQPS), Ambient Air Monitoring 
Group, Mail Code C304-06, Research Triangle Park, NC 27711.
27. U.S. Environmental Protection Agency (EPA). (2015). OSWER 
Technical Guide for Assessing and Mitigating the Vapor Intrusion 
Pathway from Subsurface Vapor Sources to Indoor Air. EPA Office of 
Solid Waste and Emergency Response (OSWER) Publication 9200.2-154. 
Available at https://www.epa.gov/vaporintrusion/technical-guide-assessing-and-mitigating-vapor-intrusion-pathway-subsurface-vapor 
(accessed September 22, 2019).
28. Wang, D.K., & Austin, C.C. (2006). Determination of complex 
mixtures of volatile organic compounds in ambient air: canister 
methodology. Analytical and Bioanalytical Chemistry, 386(4), 1099-
1120. doi:10.1007/s00216-006-0466-6.
29. Batelle. (2016). Technical Assistance Document for the National 
Air Toxics Trends Stations Program, Revision 3. Prepared for U.S. 
EPA by Battelle, Columbus, OH. Available at https://www3.epa.gov/ttn/amtic/files/ambient/airtox/NATTS%20TAD%20Revision%203_FINAL%20October%202016.pdf (accessed 
September 22, 2019).
30. Daughtrey, E.H. Jr., Oliver, K.D., Jacumin, H.H. Jr., & 
McClenny, W.A. (2004, April 20-22). Supplement to EPA Compendium 
Method TO-15--Reduction of Method Detection Limits to Meet Vapor 
Intrusion Monitoring Needs. Presented at Symposium on Air Quality 
Measurement Methods and Technology, Research Triangle Park, NC. 
Available at https://cfpub.epa.gov/si/si_public_record_report.cfm?Lab=NERL&dirEntryId=76137 (accessed 
September 22, 2019).
31. Entech Instruments. (2019). Articles and documents. Available at 
https://www.entechinst.com/technical-library/application-notes-applets-chromatograms/ (accessed September 23, 2019).
32. Kelly, T., Gordon, S., Mukund, R., & Hays, M. (1994). Ambient 
Measurement Methods and Properties of the 189 Clean Air Act 
Hazardous Air Pollutants. Report EPA/600/R-94/187 prepared under 
contract 68-DO-0007, work assignment 44, for U.S. EPA by Battelle, 
Columbus, OH.
33. Kelly, T.J., Callahan, P.J., Pleil, J., & Evans, G.F. (1993). 
Method development and field measurements for polar volatile organic 
compounds in ambient air. Environmental Science & Technology, 27(6), 
1146-1153.
34. McClenny, W.A., Oliver, K.D., & Daughtrey, E.H. Jr. (1995). 
Analysis of VOCs in ambient air using multisorbent packings for VOC 
accumulation and sample drying. Journal of the Air & Waste 
Management Association, 45(10), 792-800.
35. Morris, C., Berkley, R., & Bumgarner, J. (1983). Preparation of 
multicomponent volatile organic standards using static dilution 
bottles. Analytical Letters, 16(20), 1585-1593.
36. Oliver, K.D., Adams, J.R., Daughtrey, E.H., McClenny, W.A., 
Yoong, M.J., Pardee, M.A., Almasi, E.B., & Kirshen, N.A. (1996). 
Technique for monitoring toxic VOCs in air: Sorbent 
preconcentration, closed-cycle cooler cryofocusing, and GC/MS 
analysis. Environmental Science & Technology, 30(6), 1939-1945.
37. Pleil, J.D., & Lindstrom, A.B. (1995). Collection of a single 
alveolar exhaled breath for volatile organic compound analysis. 
American Journal of Industrial Medicine, 28(1), 109-121.
38. Pleil, J.D., McClenny, W.A., Holdren, M.W., Pollack, A.J., & 
Oliver, K.D. (1993). Spatially resolved monitoring for volatile 
organic compounds using remote sector sampling. Atmospheric 
Environment, Part A, 27(5), 739-747.
39. Pollack, A.J., Holdren, M.W., & McClenny, W.A. (1991). Multi-
adsorbent preconcentration and gas chromatographic analysis of air 
toxics with an automated collection/analytical system. Journal of 
the Air & Waste Management Association, 41(9), 1213-1217.
40. Restek. (2019). Restek Technical Library: Air Sampling. 
Available at https://www.restek.com/Technical-Resources/Technical-Library/Air-Sampling (accessed September 23, 2019).
41. Stephenson, J., Allen, F., & Slagle, T. (1990). Analysis of 
volatile organics in air via water methods. In Proceedings of the 
1990 EPA/AWMA International Symposium: Measurement of Toxic and 
Related Air Pollutants, EPA 600/9-90-026. Research Triangle Park, 
NC: U. S. Environmental Protection Agency.
42. U.S. Environmental Protection Agency (EPA). (1997). Method TO-
14A: Determination of volatile organic compounds (VOCs) in ambient 
air using specially prepared canisters with subsequent analysis by 
gas chromatography, EPA 600/625/R-96/010b. In Compendium of Methods 
for the Determination of Toxic Organic Compounds in Ambient Air, 
Second Edition. Cincinnati, OH: U.S. EPA Center for Environmental 
Research Information, Office of Research and Development.
43. Whitaker, D.A., Fortmann, R.C., & Lindstrom, A.B. (1995). 
Development and testing of a whole-air sampler for measurement of 
personal exposure to volatile organic compounds. Journal of Exposure 
Analysis & Environmental Epidemiology, 5(1), 89-100.

17.0 Tables, Diagrams, Flow Charts, etc.

                                                          Table 1--Canister Cleaning Parameters
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                              Minimum number of
            Canister type                Pre-evacuate canister       Suggested maximum          Humidity          pressure/             Cycle time
                                                                 canister temperature \a\                     evacuation cycles
--------------------------------------------------------------------------------------------------------------------------------------------------------
All..................................  Yes.....................  80 [deg]C...............                50%                  5  Varies by system.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Higher purge gas temperatures may be required depending on the canister type--do not exceed the manufacturer's recommended maximum temperatures for
  component parts such as valves and gauges.


        Table 2--BFB Tuning Check Key Ions and Abundance Criteria
------------------------------------------------------------------------
            Mass                      Ion abundance criteria \a\
------------------------------------------------------------------------
50..........................  8.0% to 40.0% of m/z 95.
75..........................  30.0% to 66.0% of m/z 95.
95..........................  Base peak, 100% relative abundance.
96..........................  5.0% to 9.0% of m/z 95.
173.........................  <2.0% of m/z 174.
174.........................  50.0% to 120.0% of m/z 95.

[[Page 43295]]

 
175.........................  4.0% to 9.0% of m/z 174.
176.........................  93.0% to 101.0% of m/z 174.
177.........................  5.0% to 9.0% of m/z 176.
------------------------------------------------------------------------
\a\ All ion abundances must be normalized to m/z 95, the nominal base
  peak, even though the ion abundance of m/z 174 may be up to 120% that
  of m/z 95.


     Table 3--Water Saturation Vapor Density at Various Temperatures
------------------------------------------------------------------------
                                                       Water saturation
                Temperature ([deg]C)                  vapor density (mg/
                                                            L) \a\
------------------------------------------------------------------------
15..................................................                12.8
16..................................................                13.6
17..................................................                14.4
18..................................................                15.3
19..................................................                16.3
20..................................................                17.3
21..................................................                18.3
22..................................................                19.4
23..................................................                20.6
24..................................................                21.8
25..................................................                23.1
26..................................................                24.4
27..................................................                25.9
28..................................................                27.3
29..................................................                28.9
30..................................................                30.5
31..................................................                32.2
32..................................................                34.0
33..................................................                35.8
------------------------------------------------------------------------
\a\ Values are generated according to the following formula (Nave,
  2017): vapor density (mg/L) = 5.018 + 0.32321 * T + 8.1847 x 10-3 * T
  \2\ + 3.1243 x 10-4 * T\3\, where: T = temperature in [deg]C.

  [GRAPHIC] [TIFF OMITTED] TR16MY24.083
  
Figure 1. Apparatus for Characterizing the Flow Control Device

[[Page 43296]]

[GRAPHIC] [TIFF OMITTED] TR16MY24.084

Figure 2. Mechanical Flow Control Device
[GRAPHIC] [TIFF OMITTED] TR16MY24.085

Figure 3. Method 327 Sampler

[[Page 43297]]

[GRAPHIC] [TIFF OMITTED] TR16MY24.086

Figure 4. Example Field Data Page

[FR Doc. 2024-07002 Filed 5-15-24; 8:45 am]
 BILLING CODE 6560-50-P