[Federal Register Volume 88, Number 79 (Tuesday, April 25, 2023)]
[Proposed Rules]
[Pages 25080-25205]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-07188]
[[Page 25079]]
Vol. 88
Tuesday,
No. 79
April 25, 2023
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; Proposed Rule
Federal Register / Vol. 88, No. 79 / Tuesday, April 25, 2023 /
Proposed Rules
[[Page 25080]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 60 and 63
[EPA-HQ-OAR-2022-0730; FRL-9327-01-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: Proposed rule.
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SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing
amendments to the New Source Performance Standards (NSPS) that apply to
the Synthetic Organic Chemical Manufacturing Industry (SOCMI) and 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
Industries (P&R I and P&R II). The EPA is proposing decisions resulting
from the Agency's technology review of the HON, P&R I, and P&R II, and
its eight-year review of the NSPS that apply to the SOCMI. The EPA is
also proposing 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 proposing to strengthen the
emission standards for ethylene oxide (EtO) emissions and chloroprene
emissions after considering the results of a risk assessment for the
HON and Neoprene Production processes subject to P&R I. Lastly, the EPA
is proposing to remove exemptions from standards for periods of
startup, shutdown, and malfunction (SSM), to add work practice
standards for such periods where appropriate, and to add provisions for
electronic reporting. We estimate that the proposed amendments to the
NESHAP would reduce hazardous air pollutants (HAP) emissions (excluding
EtO and chloroprene) from the SOCMI, P&R I, and P&R II sources by
approximately 1,123 tons per year (tpy), reduce EtO emissions from HON
processes by approximately 58 tpy, and reduce chloroprene emissions
from Neoprene Production processes in P&R I by approximately 14 tpy. We
also estimate that these proposed 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. Lastly, we estimate that the
proposed amendments to the NSPS would reduce VOC emissions from the
SOCMI source category by approximately 1,609 tpy.
DATES:
Comments. Comments must be received on or before June 26, 2023.
Under the Paperwork Reduction Act (PRA), comments on the information
collection provisions are best assured of consideration if the Office
of Management and Budget (OMB) receives a copy of your comments on or
before May 25, 2023.
Public hearing: The EPA will hold a virtual public hearing on May
16, 2023. See SUPPLEMENTARY INFORMATION for information on the public
hearing.
ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2022-0730, by any of the following methods:
Federal eRulemaking Portal: https://www.regulations.gov/
(our preferred method). Follow the online instructions for submitting
comments.
Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2022-0730 in the subject line of the message.
Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2022-0730.
Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Docket ID No. EPA-HQ-OAR-2022-0730, Mail Code 28221T, 1200
Pennsylvania Avenue NW, Washington, DC 20460.
Hand/Courier Delivery: EPA Docket Center, WJC West
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004.
The Docket Center's hours of operation are 8:30 a.m.-4:30 p.m., Monday-
Friday (except Federal Holidays).
Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received may be posted without change
to https://www.regulations.gov/, including any personal information
provided. For detailed instructions on sending comments and additional
information on the rulemaking process, see the SUPPLEMENTARY
INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Mr. Andrew Bouchard, Sector Policies
and Programs Division (E143-01), Office of Air Quality Planning and
Standards, U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina 27711; telephone number: (919) 541-4036; and email
address: [email protected].
SUPPLEMENTARY INFORMATION:
Participation in virtual public hearing. The public hearing will be
held via virtual platform on May 16, 2023. The hearing will convene at
11:00 a.m. Eastern Time (ET) and will conclude at 7:00 p.m. ET. The EPA
may close a session 15 minutes after the last pre-registered speaker
has testified if there are not additional speakers. The EPA will
announce further details on the virtual public hearing website 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. If the EPA receives a high volume of registrations
for the public hearing, we may continue the public hearing on May 17,
2023.
The EPA will begin pre-registering speakers for the hearing no
later than 1 business day following the publication of this document in
the Federal Register. The EPA will accept registrations on an
individual basis. To register to speak at the virtual hearing, please
use the online registration form available at any of the following
websites: 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, or https://www.epa.gov/stationary-sources-air-pollution/epoxy-resins-production-and-non-nylon-polyamides-national-emission; or contact the public
hearing team at (888) 372-8699 or by email at
[email protected]. The last day to pre-register to speak at the
hearing will be May 10, 2023. Prior to the hearing, the EPA will post a
general agenda that will list pre-registered speakers in approximate
order 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-
[[Page 25081]]
non-nylon-polyamides-national-emission.
The EPA will make every effort to follow the schedule as closely as
possible on the day of the hearing; however, please plan for the
hearings to run either ahead of schedule or behind schedule.
Each commenter will have 4 minutes to provide oral testimony. The
EPA encourages commenters to submit a copy of their oral testimony as
written comments to the rulemaking docket.
The EPA may ask clarifying questions during the oral presentations
but will not respond to the presentations at that time. Written
statements and supporting information submitted during the comment
period will be considered with the same weight as oral testimony and
supporting information presented at the public hearing.
Please note that any updates made to any aspect of the hearing will
be posted online 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. While the EPA expects the
hearing to go forward as set forth above, please monitor these websites
or contact the public hearing team at (888) 372-8699 or by email at
[email protected] to determine if there are any updates. The
EPA does not intend to publish a document in the Federal Register
announcing updates.
If you require the services of a translator or a special
accommodation such as audio description, please pre-register for the
hearing with the public hearing team and describe your needs by May 2,
2023. The EPA may not be able to arrange accommodations without
advanced notice.
Docket. The EPA has established a docket for this rulemaking under
Docket ID No. EPA-HQ-OAR-2022-0730. All documents in the docket are
listed in https://www.regulations.gov/. 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. With the exception of such material, publicly available docket
materials are available electronically in https://www.regulations.gov/
or in hard copy at the EPA Docket Center, Room 3334, WJC West Building,
1301 Constitution Avenue NW, Washington, DC. The Public Reading Room is
open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
legal holidays. 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.
Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2022-0730. The EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at https://www.regulations.gov/, including any personal
information provided, unless the comment includes information claimed
to be CBI or other information whose disclosure is restricted by
statute. Do not submit electronically to https://www.regulations.gov/
any information that you consider to be CBI or other information whose
disclosure is restricted by statue. This type of information should be
submitted as discussed below.
The EPA may publish any comment received to its public docket.
Multimedia submissions (audio, video, etc.) must be accompanied by a
written comment. The written comment is considered the official comment
and should include discussion of all points you wish to make. The EPA
will generally not consider comments or comment contents located
outside of the primary submission (i.e., on the Web, cloud, or other
file sharing system). For additional submission methods, the full EPA
public comment policy, information about CBI or multimedia submissions,
and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
The https://www.regulations.gov/ website allows you to submit your
comment anonymously, which means the EPA will not know your identity or
contact information unless you provide it in the body of your comment.
If you send an email comment directly to the EPA without going through
https://www.regulations.gov/, your email address will be automatically
captured and included as part of the comment that is placed in the
public docket and made available on the internet. If you submit an
electronic comment, the EPA recommends that you include your name and
other contact information in the body of your comment and with any
digital storage media you submit. If the EPA cannot read your comment
due to technical difficulties and cannot contact you for clarification,
the EPA may not be able to consider your comment. Electronic files
should not include special characters or any form of encryption and be
free of any defects or viruses. For additional information about the
EPA's public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
Submitting CBI. Do not submit information containing CBI to the EPA
through https://www.regulations.gov/. Clearly mark the part or all of
the information that you claim to be CBI. For CBI information on any
digital storage media that you mail to the EPA, note the docket ID,
mark the outside of the digital storage media as CBI, and identify
electronically within the digital storage media the specific
information that is claimed as CBI. In addition to one complete version
of the comments that includes information claimed as CBI, you must
submit a copy of the comments that does not contain the information
claimed as CBI directly to the public docket through the procedures
outlined in Instructions above. If you submit any digital storage media
that does not contain CBI, mark the outside of the digital storage
media clearly that it does not contain CBI and note the docket ID.
Information not marked as CBI will be included in the public docket and
the EPA's electronic public docket without prior notice. Information
marked as CBI will not be disclosed except in accordance with
procedures set forth in 40 Code of Federal Regulations (CFR) part 2.
Our preferred method to receive CBI is for it to be transmitted
electronically using email attachments, File Transfer Protocol, or
other online file sharing services (e.g., Dropbox, OneDrive, Google
Drive). Electronic submissions must be transmitted directly to the
Office of Air Quality Planning and Standards (OAQPS) CBI Office at the
email address [email protected] and, as described above, should include
clear CBI markings and note the docket ID. 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.
If sending CBI information through the postal service, please send it
to the following address: OAQPS Document Control Officer (C404-02),
OAQPS, U.S. Environmental Protection Agency, Research Triangle Park,
North Carolina 27711, Attention Docket ID No. EPA-HQ-OAR-2022-0730. The
mailed CBI material should be double wrapped and clearly marked. Any
CBI markings should not show through the outer envelope.
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Preamble acronyms and abbreviations. Throughout this preamble the
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. 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
ADAF age-dependent adjustment factor
AEGL acute exposure guideline levels
AERMOD American Meteorological Society/EPA Regulatory Model
dispersion modeling system
AIHA American Industrial Hygiene Association
AMEL alternative means of emission limitation
APCD air pollution control device
ATSDR Agency for Toxic Substances and Disease Registry
1-BP 1-bromopropane
BAAQMD Bay Area Air Quality Management District
BACT Best Available Control Technology
BLR basic liquid epoxy resins
BPT benefit per-ton
BSER best system of emissions reduction
BTU British thermal units
CAA Clean Air Act
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CMAS Chemical Manufacturing Area Sources
CMPU chemical manufacturing process unit
CO carbon monoxide
CO2 carbon dioxide
EAV equivalent annual value
ECHO Enforcement and Compliance History Online
EFR external floating roof
EIS Emission Information System
EJ environmental justice
EMACT Ethylene Production MACT
EPA Environmental Protection Agency
EPPU elastomer product process unit
ERPG emergency response planning guidelines
ERT Electronic Reporting Tool
EtO Ethylene Oxide
FID flame ionization detector
GACT generally available control technologies
HAP hazardous air pollutant(s)
HCl hydrochloric acid
HEM Human Exposure Model
HF hydrofluoric acid
HON Hazardous Organic NESHAP
HQ hazard quotient
HQREL hazard quotient reference exposure level
HRVOC highly reactive volatile organic compound
ICR information collection request
IFR internal floating roof
IRIS Integrated Risk Information System
ISA Integrated Science Assessment
ISO International Standards Organization
km kilometer
kPa kilopascals
LAER Lowest Achievable Emission Rate
lb/hr pound per hour
LDAR leak detection and repair
LDSN leak detection sensor network
LEL lower explosive limit
MACT maximum achievable control technology
MPGF multi-point ground flare
MIR maximum individual lifetime [cancer] risk
MON Miscellaneous Organic Chemical Manufacturing NESHAP
MTVP maximum true vapor pressure
NAAQS National Ambient Air Quality Standard
NAICS North American Industry Classification System
NEI National Emissions Inventory
NESHAP national emission standards for hazardous air pollutants
NHVcz net heating value in the combustion zone gas
NHVdil net heating value dilution parameter
NHVvg net heating value in the vent gas
NOAEL No Observed Adverse Effects Level
NOX nitrogen oxides
N2O nitrous oxide
NRDC Natural Resources Defense Council
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OAR Office of Air and Radiation
OECA Office of Enforcement and Compliance Assurance's
OEL open-ended valves or lines
OGI optical gas imaging
OLD Organic Liquids Distribution
OMB Office of Management and Budget
OSHA Occupational Safety and Health Administration
P&R I Group I Polymers and Resins NESHAP
P&R II Group II Polymers and Resins NESHAP
PDF portable document format
PM2.5 particulate matter 2.5
POM polycyclic organic matter
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 devices
PV present value
RACT Reasonably Available Control Technology
RDL representative detection limit
REL Reference Exposure Level
RFA Regulatory Flexibility Act
RfC reference concentration
RIA Regulatory Impact Analysis
RTR Risk and Technology Reviews
SCAQMD South Coast Air Quality Management District
scmm standard cubic meter per minute
scf standard cubic foot
SOCMI Synthetic Organic Chemical Manufacturing Industry
SO2 sulfur dioxide
SSM startup, shutdown, and malfunction
TAC Texas Administrative Code
TCEQ Texas Commission on Environmental Quality
TOC total organic carbon
TOSHI target organ-specific hazard index
tpy tons per year
TRE total resource effectiveness
TRIM Total Risk Integrated Methodology
UF uncertainty factor
UMRA Unfunded Mandates Reform Act
UPL upper prediction limit
URE unit risk estimate
U.S.C. United States Code
USGS U.S. Geological Survey
VOC volatile organic compound(s)
WSR wet strength resins
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?
II. Background
A. What is the statutory authority for this action?
B. What are the source categories and how do the current
standards regulate emissions?
C. What data collection activities were conducted to support
this action?
D. What other relevant background information and data are
available?
E. How do we consider risk in our decision-making?
F. How do we estimate post-MACT risk posed by the source
category?
G. How does the EPA perform the NESHAP technology review and
NSPS review?
III. Proposed Rule Summary and Rationale
A. What are the results of the risk assessment and analyses?
B. What are our proposed decisions regarding risk acceptability,
ample margin of safety, and adverse environmental effect?
C. What are the results and proposed decisions based on our CAA
section 112(d)(6) technology review and CAA section 111(b)(1)(B)
NSPS reviews, and what are the rationale for those decisions?
D. What actions related to CAA section 112(d)(2) and (3) are we
taking in addition to those identified in the CAA sections 112(f)(2)
and (d)(6) risk and technology reviews and CAA section 111(b)(1)(B)
NSPS reviews?
E. What other actions are we proposing, and what is the
rationale for those actions?
F. What compliance dates are we proposing, and what is the
rationale for the proposed compliance dates?
IV. Summary of Cost, Environmental, and Economic Impacts
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. What analysis of children's environmental health did we
conduct?
V. Request for Comments
VI. Statutory and Executive Order Reviews
[[Page 25083]]
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and 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
I. General Information
A. Executive Summary
1. Purpose of the Regulatory Action
The source categories that are the subject of this proposal are the
SOCMI and various polymers and resins source categories. The SOCMI
source category includes chemical manufacturing processes producing
commodity chemicals while the polymers and resins 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 CFR part 63,
subparts F, G, and H. In 1994, the EPA finalized MACT standards in
subparts F, G, and H for SOCMI processes (59 FR 19454),\1\ and
conducted a residual risk and technology review for these NESHAP in
2006 (71 FR 76603). In 1995, the EPA finalized MACT standards in P&R II
(40 CFR part 63, subpart W) for epoxy resin and non-nylon polyamide
resin manufacturing processes (60 FR 12670) and completed a residual
risk and technology review for these standards in 2008 (73 FR 76220).
In 1996, the EPA finalized MACT standards in P&R I (40 CFR part 63,
subpart U) for elastomer manufacturing processes in the SOCMI source
category (61 FR 46906) and completed residual risk and technology
reviews 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 reflects 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 Clean Air Act (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 non-air 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 emission 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 8 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
standards for a source category do not provide ``an ample margin of
safety to protect public health,'' the EPA must 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 proposed 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. In
addition, the EPA is proposing 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
and of which the Agency has granted reconsideration pursuant to section
307(d)(7)(B) of the CAA. These proposed amendments are primarily
included in the new NSPS subpart VVb; the EPA is not proposing to make
these changes in subparts VV and VVa because, in light of the time that
has passed since the promulgation of these two subparts, the EPA finds
it inappropriate to now change the obligations of sources subject to
these subparts after all these years. The proposed amendments to the
HON (NESHAP subparts F, G, H, and I), P&R I (NESHAP subpart U), and P&R
II (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 section 112(d).
Also, 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 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
[[Page 25084]]
unacceptable residual cancer risk caused by chloroprene emissions from
affected sources producing neoprene subject to P&R I.\2\ 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. 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 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.
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\2\ As discussed further in section III.B of this preamble,
chloroprene emissions from HON processes do not on their own present
unacceptable cancer risk.
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2. Summary of the Major Provisions of the Regulatory Action in Question
The most significant amendments that we are proposing are described
briefly below. However, all of our proposed amendments, including
amendments to remove exemptions for periods of SSM, are discussed in
detail with rationale in section III of this preamble.
a. HON
We are proposing 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 proposing:
Compliance dates for all of the proposed HON requirements
(see proposed 40 CFR 63.100(k)(10) through (12); and section III.F of
this preamble).
to move all of 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 proposed 40 CFR 63.101; and
section III.E.5.a of this preamble).
a new definition for ``in ethylene oxide service'' (for
equipment leaks, heat exchange systems, process vents, storage vessels,
and wastewater) (see proposed 40 CFR 63.101; and section III.B.2.a of
this preamble).
new operating and monitoring requirements for flares; and
a requirement 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 (see proposed 40 CFR 63.108; and section III.B.2.a.vi of this
preamble).
sampling and analysis procedures for owners and operators
to demonstrate that process equipment does, or does not, meet the
proposed definition of being ``in ethylene oxide service'' (see
proposed 40 CFR 63.109; and section III.B.2.a.vii of this preamble).
For heat exchange systems, we are proposing:
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 parts per million by volume
(ppmv) or greater (see proposed 40 CFR 63.104(g) through (j); and
section III.C.1 of this preamble).
to require owners or 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 (see proposed 40 CFR 63.104(g)(6) and
(h)(6); and section III.B.2.a.iii of this preamble).
that the current leak monitoring requirements for heat
exchange systems at 40 CFR 63.104(b) may be used 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 proposed 40 CFR 63.104(l); and section III.C.1 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 proposing:
To remove 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 require 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 proposed 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, whichever is less stringent (see proposed 40
CFR 63.101 and 40 CFR 63.113(a)(1) and (2); and section III.C.3.a of
this preamble).
to remove the total resource effectiveness (TRE) concept
in its entirety (see proposed 40 CFR 63.113(a)(4); and section
III.C.3.a of this preamble).
to add 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
proposed 40 CFR 63.113(a)(5); and section III.D.5. of this preamble).
that owners and operators 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 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 (see proposed 40 CFR 63.113(j), 40 CFR 63.108, and
40 CFR 63.124; and section III.B.2.a.i of this preamble).\3\
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\3\ We are also proposing to remove the option to allow use of a
design evaluation in lieu of performance testing to demonstrate
compliance for controlling various emission sources in ethylene
oxide service. In addition, owners or operators that choose to
control emissions with a non-flare control device would be required
to conduct an initial performance test on each control device in
ethylene oxide service to verify performance at the required level
of control, and would also be required to conduct periodic
performance testing on non-flare control devices in ethylene oxide
service every 5 years (see proposed 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
[[Page 25085]]
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 (see proposed
40 CFR 63.113(k); and section III.D.4.a of this preamble).
that owners and operators of process vents in EtO service
would not be allowed to use the proposed maintenance vent work practice
standards; instead, owners and operators would be prohibited from
releasing more than 1.0 ton of EtO from all maintenance vents combined
in any consecutive 12-month period (see proposed 40 CFR 63.113(k)(4);
and section III.B.2.a.v of this preamble).
For storage vessels, we are proposing:
That owners and operators 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 (see proposed 40
CFR 63.119(a)(5), 40 CFR 63.108, and 40 CFR 63.124; and section
III.B.2.a.i 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., less than 10 percent of the LEL) and all
standing liquid has been removed from the vessel to the extent
practicable (see proposed 40 CFR 63.119(a)(6); and section III.D.4.b of
this preamble).
to define pressure vessel and 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 (see proposed 40 CFR 63.101); and require initial and
annual performance testing using EPA Method 21 of 40 CFR part 60,
appendix A-7 to demonstrate no detectable emissions (i.e., would be
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 proposed 40 CFR 63.119(a)(7); and section
III.D.6 of this preamble).
to require 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 the deck cover would be required to be equipped with a
gasket between the cover and the deck (see proposed 40 CFR
63.119(b)(5)(ix); and section III.C.2 of this preamble).
controls for guidepoles for all storage vessels equipped
with an IFR (see proposed 40 CFR 63.119(b)(5)(x), (xi), and (xii); and
section III.C.2 of this preamble).
a work practice standard that would apply 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 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 while working losses are controlled)
(see proposed 40 CFR 63.119(e)(7); and section III.D.4.c of this
preamble).
to revise 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 proposed Table
5 to subpart G; and section III.C.2 of this preamble).
to revise the Group 1 stored-liquid maximum true vapor
pressure (MTVP) of total organic HAP threshold (for storage vessels at
existing sources) from greater than or equal to 13.1 kilopascals (kPa)
to greater than or equal to 6.9 kPa (see proposed Table 5 to subpart G;
and section III.C.2 of this preamble).
For transfer racks, we are proposing:
To remove the exemption for transfer operations that load
``at an operating pressure greater than 204.9 kilopascals'' from the
definition of transfer operation (see proposed 40 CFR 63.101; and
section III.D.8 of this preamble).
For wastewater streams, we are proposing:
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 ppm by weight at any flow rate) (see proposed 40 CFR
63.132(c)(1)(iii) and (d)(1)(ii); and section III.B.2.a.iv of this
preamble).
to prohibit owners and operators from injecting wastewater
into or disposing of water through any heat exchange system in a
chemical manufacturing process unit (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
proposed 40 CFR 63.104(k); and section III.B.2.a.iv of this preamble).
For closed vent systems, we are proposing:
That owners and operators may not bypass an air pollution
control device (APCD) at any time (see proposed 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 proposed 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 section III.D.3 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 the HON, we are proposing 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 proposing:
That all connectors in EtO service would be required to be
monitored monthly at a leak definition of 100 ppm with no skip period,
and delay of repair would not be allowed (see proposed 40 CFR
63.174(a)(3), (b)(3)(vi), and (g)(3), and 40 CFR 63.171(f); and section
III.B.2.a.ii of this preamble).
that all gas/vapor and light liquid valves in EtO service
would be required to be monitored monthly at a leak definition of 100
ppm with no skip period, and delay of repairs would not be allowed (see
proposed 40 CFR 63.168(b)(2)(iv) and (d)(5), and 40 CFR 63.171(f); and
section III.B.2.a.ii of this preamble).
that all light liquid pumps in EtO service would be
required to be monitored monthly at a leak definition of 500 ppm, and
delay of repairs would not be allowed (see proposed 40 CFR
63.163(a)(1)(iii), (b)(2)(iv), (c)(4), and (e)(7), and 40 CFR
63.171(f); and section III.B.2.a.ii of this preamble).
a work practice standard for pressure relief devices
(PRDs) that vent to the atmosphere that would require owners and
operators to implement at least three prevention measures, perform root
cause analysis and corrective action in the event that a PRD
[[Page 25086]]
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 proposed 40 CFR 63.165(e); and
section III.D.2 of this preamble).
that all surge control vessels and bottoms receivers would
be required to meet the requirements we are proposing for process vents
(see proposed 40 CFR 63.170(b); and section III.D.7 of this preamble).
that owners and operators may not bypass an APCD at any
time (see proposed 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 proposed 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 section III.D.3 of this preamble).
to add a fenceline monitoring standard that requires
owners and operators to monitor for any of 6 specific HAP they emit
(i.e., benzene, 1,3-butadiene, ethylene dichloride, vinyl chloride,
EtO, and chloroprene) and conduct root cause analysis and corrective
action upon exceeding the annual average concentration action level set
forth for each HAP (see proposed 40 CFR 63.184; and section III.C.7 of
this preamble).
b. P&R I
As detailed in section II.B.2 of this preamble, P&R I (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
proposing amendments to P&R I for heat exchange systems, process vents,
storage vessels, wastewater, and equipment leaks. For NESHAP subpart U,
we are proposing:
Compliance dates for all of the proposed P&R I
requirements (see proposed 40 CFR 63.481(n) and (o); and section III.F
of this preamble).
new operating and monitoring requirements for flares (see
proposed 40 CFR 63.508; and section III.D.1 of this preamble).
removing provisions to assert an affirmative defense to
civil penalties (see proposed 40 CFR 63.480(j)(4); and section III.E.2
of this preamble).
to reference the same fenceline monitoring requirements
that we are proposing 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 proposed definition of being ``in
chloroprene service'' (see proposed 40 CFR 63.509; and section
III.B.2.b.iv of this preamble).
A facility-wide chloroprene emissions cap of 3.8 tpy in
any consecutive 12-month period for all neoprene production emission
sources (see proposed 40 CFR 63.483(a)(10); and section III.B.2.b.v of
this preamble).
For heat exchange systems, we are proposing:
To add the same requirements (except for EtO standards)
listed in section I.A.2.a.i of this preamble that we are proposing for
heat exchange systems subject to the HON to also apply to heat exchange
systems subject to P&R I (see proposed 40 CFR 63.502(n)(7); and section
III.C.1 of this preamble).
For continuous front-end process vents, we are proposing:
That owners and operators 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 (see proposed 40 CFR 63.485(y),
and 40 CFR 63.510; and sections III.B.2.b.i of this preamble).\5\
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\5\ We are also proposing to remove 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 would be 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 would also be required to conduct periodic
performance testing on non-flare control devices in chloroprene
service every 5 years (see proposed 40 CFR 63.510).
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to add the same requirements (except for EtO standards)
listed in section I.A.2.a.ii of this preamble that we are proposing for
process vents subject to the HON to also apply to continuous front-end
process vents subject to P&R I (see proposed 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 section
III.C.3 of this preamble).
that continuous front-end process vents in chloroprene
service would not be allowed to use the proposed maintenance vent work
practice standards; instead, owners and operators would be prohibited
from releasing more than 1.0 ton of chloroprene from all maintenance
vents combined in any consecutive 12-month period (see proposed 40 CFR
63.485(z); and section III.B.2.b.iii of this preamble).
to add an emission standard of 0.054 ng/dscm at 3 percent
oxygen (toxic equivalency basis) for dioxins and furans from
chlorinated continuous front-end process vents (see proposed 40 CFR
63.485(x); and section III.D.5. of this preamble).
For batch front-end process vents, we are proposing:
To remove 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 are currently 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 would be required to reduce emissions of organic HAP from
these process vents using a flare meeting the proposed 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 proposed 40 CFR 63.482, 40 CFR
63.487I(1)(iv), 40 CFR 63.488(d)(2), (e)(4), (f)(2), and (g)(3); and
section III.C.3 of this preamble).
to add the same chloroprene standards that we are
proposing for continuous front-end process for batch front-end process
vents at affected sources producing neoprene (see proposed 40 CFR
63.487(j); and section III.B.2.b.i of this preamble).
to add the same work practice standards that we are
proposing for maintenance vents as described for HON to P&R I (see
proposed 40 CFR 63.487(i); and section III.D.4.a of this preamble).
that batch front-end process vents in chloroprene service
would not be allowed to use the proposed maintenance vent work practice
standards; instead, owners and operators would be prohibited from
releasing more than 1.0 tons of chloroprene from all maintenance vents
combined in any consecutive 12-month period (see proposed 40 CFR
63.487(i)(4); and section III.B.2.b.v of this preamble).
to add an emission standard of 0.054 ng/dscm at 3 percent
oxygen
[[Page 25087]]
(toxic equivalency basis) for dioxins and furans from chlorinated batch
front-end process vents (see proposed 40 CFR 63.487(a)(3) and (b)(3);
and section III.D.5. of this preamble).
For storage vessels, we are proposing:
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 99.9 percent by weight or to a concentration less than 1 ppmv
for each storage vessel vent (see proposed 40 CFR 63.484(u) and 40 CFR
63.510; and section III.B.2.b.i of this preamble).\6\
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\6\ See footnote 5.
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to add the same requirements (except for EtO standards)
listed in section I.A.2.a.ii of this preamble that we are proposing for
storage vessels subject to the HON except the proposed requirements
would apply to storage vessels subject to P&R I (see proposed 40 CFR
63.484(t); and section III.C.2 of this preamble).
For wastewater streams, we are proposing:
To revise 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 parts per
million by weight (ppmw) at any flow rate) (see proposed 40 CFR
63.501(a)(10)(iv); and section III.B.2.b.ii of this preamble).
to prohibit owners and operators from injecting wastewater
into or disposing of water through any heat exchange system in an
elastomer product process unit (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 proposed 40 CFR 63.502(n)(8); and section III.B.2.b.ii of
this preamble).
For equipment leaks and fenceline monitoring, we are proposing:
To add the same requirements (except for EtO standards)
listed in section I.A.2.a.iii of this preamble that we are proposing
for equipment leaks subject to the HON except the proposed requirements
would apply to equipment leaks subject to P&R I (see proposed 40 CFR
63.502(a)(1) through (a)(6); and sections III.D.2 and III.D.3 of this
preamble).
to cross-reference P&R I facilities to the same fenceline
monitoring standard in the HON (see proposed 40 CFR 63.184) that
requires owners and operators to monitor for any of 6 specific HAP they
emit (i.e., benzene, 1,3-butadiene, ethylene dichloride, vinyl
chloride, EtO, and chloroprene) and conduct root cause analysis and
corrective action upon exceeding the annual average concentration
action level set forth for each HAP (see section III.C.7 of this
preamble).
c. P&R II
The most significant amendments that we are proposing for P&R II
(40 CFR part 63, subpart W) are to add requirements for heat exchange
systems (see proposed 40 CFR 63.523(d) and 40 CFR 63.524(c); and
section III.D.9 of this preamble) and require 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 proposed 40 CFR
63.524(a)(3) and (b)(3); and section III.D.10 of this preamble). We are
also proposing to add 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 P&R I (see proposed 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)).
d. NSPS Subparts III, NNN, and RRR
We are proposing to amend the applicability of NSPS subparts III,
NNN, and RRR so that they would 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 would be subject to the new proposed NSPS subparts IIIa, NNNa,
and RRRa (see section A.2.e of this preamble).
e. NSPS Subparts IIIa, NNNa, and RRRa
Rather than comply with a TRE concept which is currently used in
NSPS subparts III, NNN, and RRR, we are proposing in new NSPS subparts
IIIa, NNNa, and RRRa to require owners and operators to reduce
emissions of total organic carbon (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, whichever is less stringent,
or combust the emissions in a flare meeting the same operating and
monitoring requirements for flares that we are proposing for flares
subject to the HON. We are also proposing to 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. In addition, we are proposing the
same work practice standards for maintenance vents that we are
proposing for HON process vents, and the same monitoring requirements
that we are proposing for HON process vents for adsorbers that cannot
be regenerated and regenerative adsorbers that are regenerated offsite
(see section III.C.3.b of this preamble).
f. NSPS Subpart VVa
We are proposing to amend the applicability of the existing NSPS
subpart VVa so that it would apply to only 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 would be subject to the
new proposed NSPS subpart VVb.
g. NSPS Subpart VVb
We are proposing 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 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 section III.C.6.b of this preamble). For each of these two
additional requirements, we are also proposing 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, (referred to as the RIA in this
document) is available in the docket, and is also briefly summarized in
section VI of this preamble.
B. Does this action apply to me?
The source categories that are the subject of this proposal include
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
[[Page 25088]]
Polymers and Resins Production source categories covered in P&R I and
P&R II (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 is 325212, and for P&R II 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 proposed action is likely to
affect. The proposed standards, once promulgated, will be directly
applicable to the affected sources and/or affected facilities. Federal,
state, local, and tribal government entities would not be affected by
this proposed action.
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\7\ P&R I includes 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). P&R II includes two listed source categories that
use epichlorohydrin feedstock (Epoxy Resins Production and Non-Nylon
Polyamides Production).
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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 P&R I and resins produced
with epichlorohydrin feedstock in P&R II have many similar emission
sources with SOCMI sources and are discussed further in section II.B of
this preamble.
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\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.
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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 for this source
category, the EPA considered emission sources associated with unit
processes, storage and handling equipment, fugitive emission sources,
and secondary sources.
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\9\ For readability, we also refer to this as the SOCMI source
category for purposes of the NSPS.
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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 action is available on the internet. Following signature by the
EPA Administrator, the EPA will post a copy of this proposed 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 of the proposal and key
technical documents at these same websites.
A memorandum showing the edits that would be necessary to
incorporate the changes to: 40 CFR part 60, subparts VV, VVa, III, NNN,
RRR; 40 CFR part 63, subparts F, G, H and I (HON), U (P&R I), and W
(P&R II); and 40 CFR part 60, new subparts VVb, IIIa, NNNa, and RRRa
proposed in this action are available in the docket (Docket ID No. EPA-
HQ-OAR-2022-0730). Following signature by the EPA Administrator, the
EPA also will post a copy of these documents to 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.
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. Generally, the first stage involves establishing technology-
based standards and the second stage involves evaluating those
standards that are based on MACT to determine whether additional
standards are needed to address any remaining risk associated with HAP
emissions. This second stage is commonly referred to as the ``residual
risk review.'' In addition to the residual risk review, the CAA also
requires the EPA to review standards set under CAA section 112 every 8
years and revise the standards as necessary taking into account any
``developments in practices, processes, and control technologies.''
This review is commonly referred to as the ``technology review.'' When
the two reviews are combined into a single rulemaking, it is commonly
referred to as the ``risk and technology review.'' The discussion that
follows identifies the most relevant statutory sections and briefly
explains the contours of the methodology used to implement these
statutory requirements. A more comprehensive discussion appears in the
document titled CAA Section 112 Risk and Technology Reviews: Statutory
Authority and Methodology, in the docket for this rulemaking.
In the first stage of the CAA section 112 standard setting process,
the EPA promulgates technology-based standards under CAA section 112(d)
for categories of sources identified as emitting one or more of the HAP
listed in CAA section 112(b). Sources of HAP emissions are either major
sources or area sources, and CAA section 112 establishes different
requirements for major source standards and area source standards.
``Major sources'' are those that emit or have the potential to emit 10
tpy or more of a single HAP or 25 tpy or more of any combination of
HAP. All other sources are ``area sources.'' For major sources, CAA
section 112(d)(2) provides that the technology-based NESHAP must
reflect the maximum degree of emission reductions of HAP achievable
(after considering cost, energy requirements, and non-air quality
health and environmental impacts). These standards are commonly
referred to as MACT standards. CAA section 112(d)(3) also establishes a
minimum control level for MACT standards, known as the MACT ``floor.''
In certain instances, as provided in CAA section 112(h), the EPA may
set work practice standards in lieu of numerical emission standards.
[[Page 25089]]
The EPA must also consider control options that are more stringent than
the floor. Standards more stringent than the floor are commonly
referred to as beyond-the-floor standards. For area sources, CAA
section 112(d)(5) gives the EPA discretion to set standards based on
generally available control technologies or management practices (GACT
standards) in lieu of MACT standards.
The second stage in standard-setting focuses on identifying and
addressing any remaining (i.e., ``residual'') risk pursuant to CAA
section 112(f). For source categories subject to MACT standards,
section 112(f)(2) of the CAA requires the EPA to determine whether
promulgation of additional standards is needed to provide an ample
margin of safety to protect public health or to prevent an adverse
environmental effect. Section 112(d)(5) of the CAA provides that this
residual risk review is not required for categories of area sources
subject to GACT standards. Section 112(f)(2)(B) of the CAA further
expressly preserves the EPA's use of the two-step approach for
developing standards to address any residual risk and the Agency's
interpretation of ``ample margin of safety'' developed in the 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 (Benzene NESHAP) (54 FR 38044, September 14, 1989). The EPA
notified Congress in the Residual Risk Report that the Agency intended
to use the 1989 Benzene NESHAP approach in making CAA section 112(f)
residual risk determinations (EPA-453/R-99-001, p. ES-11). The EPA
subsequently adopted this approach in its residual risk determinations
and the United States Court of Appeals for the District of Columbia
Circuit upheld the EPA's interpretation that CAA section 112(f)(2)
incorporates the approach established in the 1989 Benzene NESHAP. See
Natural Resources Defense Council (NRDC) v. EPA, 529 F.3d 1077, 1083
(D.C. Cir. 2008).
The approach incorporated into the CAA and used by the EPA to
evaluate residual risk and to develop standards under CAA section
112(f)(2) is a two-step approach. In the first step, the EPA determines
whether risks are acceptable. This determination ``considers all health
information, including risk estimation uncertainty, and includes a
presumptive limit on maximum individual lifetime [cancer] risk (MIR)
\10\ of approximately 1 in 10 thousand.'' (54 FR 38045). If risks are
unacceptable, the EPA must determine the emissions standards necessary
to reduce risk to an acceptable level without considering costs. In the
second step of the approach, 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. The EPA must promulgate 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.
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\10\ Although defined as ``maximum individual risk,'' MIR refers
only to cancer risk. MIR, one metric for assessing cancer risk, is
the estimated risk if an individual were exposed to the maximum
level of a pollutant for a lifetime.
---------------------------------------------------------------------------
CAA section 112(d)(6) 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 8 years. In conducting this
review, which we call the ``technology review,'' the EPA is not
required to recalculate the MACT floors that were established in
earlier rulemakings. NRDC v. EPA, 529 F.3d at 1084; 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 MACT standards for listed air toxics known to be
emitted from major source categories, 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 (LEAN) v. EPA, 955 F.3d 1088 (D.C. Cir. 2020).
The EPA conducted a residual risk and technology review 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 residual risk and technology review 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 residual risk and
technology review 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); and 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).
This action constitutes another CAA section 112(d)(6) technology
review for the HON, P&R I, and P&R II. 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 P&R I. 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 standards for affected sources producing neoprene subject to
P&R I, the EPA retains discretion to revisit its residual risk reviews
where the Agency deems that is warranted. See, e.g., Fed. Commc'ns
Comm'n v. Fox Television Stations, Inc., 556 U.S. 502, 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)
(in residual risk review for EtO, EPA asserting its ``authority 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
[[Page 25090]]
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 section 112(f). In particular, the EPA is concerned about
the cancer risks posed from the SOCMI (i.e., HON) 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.\11\ The EPA's
2006 risk and technology review (RTR) could not have had the benefit of
this updated URE at the time it was conducted, but if it had would have
necessarily resulted in different conclusions about risk acceptability
and the HON's provision of 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 and, therefore,
no cancer risk was attributed to chloroprene emissions in either of
those risk reviews. The EPA's 2006 and 2008 RTRs could not have had the
benefit of this new URE at the time they were conducted, but if they
had would have necessarily resulted in different conclusions about risk
acceptability and P&R I's provision of an ample margin of safety to
protect public health. The development of the EPA's IRIS inhalation URE
for chloroprene was concluded in 2010, which allows us to assess cancer
risks posed by chloroprene for the first time. Thus, we are conducting
this analysis in this action. 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 P&R I.
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.\12\ 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 P&R I, stating that we intend to
conduct a human health risk assessment concurrently with the section
112(d)(6) review.\13\ This proposed rulemaking is partly undertaken to
take action 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 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.
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\11\ 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.
\12\ See letter dated September 15, 2021, from Joseph Goffman to
Kathleen Riley, Emma Cheuse, and Adam Kron which is available in the
docket for this rulemaking.
\13\ See letter dated March 4, 2022, from Joseph Goffman to Emma
Cheuse, Deena Tumeh, Michelle Mabson, Maryum Jordan, and Dorian
Spence which is available in the docket for this rulemaking.
---------------------------------------------------------------------------
2. NSPS
The EPA's authority for this proposed rule related to NSPS 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 non-air 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 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
[[Page 25091]]
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. Pursuant to CAA section
111(b)(1)(B), the standards of performance or revisions thereof shall
become effective upon promulgation.
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 proposed 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 proposed action under section 111(b)(1)(B)
described above, this action includes proposed amendments to the NSPS
for VOC from equipment leaks in SOCMI based on its reconsideration of
certain aspects of NSPS subparts VV and VVa that were raised in an
administrative petition and of which the Agency has granted
reconsideration 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, 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
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.\14\ 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 take final action on the issues of
which 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.
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\14\ Note that this action does not respond to the
reconsideration of NSPS subparts GGG and GGGa, as the EPA is not
reviewing those subparts in this action.
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In the June 2, 2008, actions, the EPA indicated that it would be
publishing a Federal Register notice in response to the petition;
therefore, the purpose of today's notice is to formally respond to the
issues raised in the petition with respect to NSPS subparts VV and VVa.
This proposed action presents the EPA's proposed 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
proposing amendments that address the stay on issue (1) in the
petition. See section III.E.4 of this preamble for details about these
proposed amendments.
B. What are the source categories and how do the current standards
regulate emissions?
The source categories that are the subject of this proposal are the
SOCMI source category subject to the HON and 11 Polymers and Resins
Production source categories subject to P&R I and P&R II. 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 current 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 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,\15\ 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
[[Page 25092]]
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.
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\15\ See Table 1 to NESHAP subpart F.
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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 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, whichever is less stringent; or achieve and maintain a TRE
index value \16\ greater than 1.0.\17\
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\16\ See section III.C.3.a of this preamble for a description of
the TRE index value and how the concept is currently used in the
HON.
\17\ 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.
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Group 1 transfer racks must reduce emissions of total
organic HAP by 98 percent by weight or to an exit concentration of 20
ppmv, whichever is less stringent; 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.
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 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
P&R I generally follows and refers to the requirements of the HON,
with additional requirements for batch process vents. Generally, P&R I
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
[[Page 25093]]
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 P&R I 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 P&R I. 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 P&R I. 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 P&R I.
3. P&R II
P&R II regulates HAP emissions from two source categories, Epoxy
Resins Production (also referred to as basic liquid epoxy resins or
BLR) and Non-Nylon Polyamides Production (also referred to as wet
strength resins or WSR). P&R II takes a different regulatory and format
approach from P&R I 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 P&R II 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. Owners and operators
of an affected facility must 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, whichever is less stringent;
combust the emissions in a flare meeting 40 CFR 60.18(b); or maintain a
TRE index value \18\ greater than 1.0 without use of VOC emission
control devices.
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\18\ See section III.C.3.b of this preamble for a description of
the TRE index value and how the concept is currently used in NSPS
Subpart III.
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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. Owners and operators of an affected
facility must 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,
[[Page 25094]]
whichever is less stringent; combust the emissions in a flare meeting
40 CFR 60.18(b); or maintain a TRE index value \19\ greater than 1.0
without use of VOC emission control devices.
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\19\ See section III.C.3.b of this preamble for a description of
the TRE index value and how the concept is currently used in NSPS
Subpart NNN.
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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. Owners and operators of an affected facility
must 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, whichever is less stringent; combust the emissions in
a flare meeting 40 CFR 60.18(b); or maintain a TRE index value \20\
greater than 1.0 without use of VOC emission control devices.
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\20\ See section III.C.3.b of this preamble for a description of
the TRE index value and how the concept is currently used in NSPS
Subpart RRR.
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C. What data collection activities were conducted to support this
action?
The EPA used several data sources to determine the facilities that
are subject to the NESHAP and NSPS discussed in section II.B of this
preamble. We identified facilities in the 2017 National Emissions
Inventory (NEI) and the Toxics Release Inventory system having a
primary facility NAICS code beginning with 325, Chemical Manufacturing.
We also used information from the 2006 HON RTR, the 2008 and 2011 P&R
RTRs, other internal chemical sector facility lists from the EPA's
recent petrochemical sector RTR rulemakings (e.g., Miscellaneous
Organic Chemical Manufacturing NESHAP (MON), Organic Liquids
Distribution (Non-Gasoline) NESHAP (OLD), Ethylene Production MACT
standards (EMACT), and Petroleum Refinery MACT 1 standards (the
Petroleum Refinery Sector rule)), and the Office of Enforcement and
Compliance Assurance's (OECA) Enforcement and Compliance History Online
(ECHO) tool (https://echo.epa.gov). To inform our reviews of our
emission standards, we reviewed the EPA's Reasonably Available Control
Technology (RACT)/Best Available Control Technology (BACT)/Lowest
Achievable Emission Rate (LAER) Clearinghouse and regulatory
development efforts for similar sources published after the rules that
are subject to this proposal were developed. The EPA also reviewed air
permits to determine facilities subject to the HON, and P&R I and P&R
II. We also met with industry representatives from the American
Chemistry Council, American Fuel & Petrochemical Manufacturers, and
Vinyl Institute to collect data and discuss industry practices.
In June 2021 and January 2022, the EPA issued requests, pursuant to
CAA section 114, to collect information from HON facilities (one being
also subject to P&R I and several being also subject to NSPS subparts
III, NNN, and/or RRR) owned and operated by nine entities (i.e.,
corporations). Many of the entities chosen have facilities that
produce, use, and emit EtO or chloroprene, which are pollutants with
considerable concern for cancer risk for the SOCMI and Neoprene
Production source categories. This effort focused on gathering
comprehensive information about process equipment, control
technologies, point and fugitive emissions, and other aspects of
facility operations. Companies submitted responses (and follow-up
responses) to the EPA between March 2022 and December 2022 (for the
January 2022 request). Additionally, as part of the January 2022 CAA
section 114 requests, the EPA requested stack testing for certain
emission sources (e.g., pollutants for vent streams associated with
each EtO production line). Also, the EPA required, as part of the
January 2022 CAA section 114 request, that facilities conduct fugitive
emission testing (i.e., fenceline monitoring) for benzene, 1,3-
butadiene, chloroprene, EtO, ethylene dichloride, or vinyl chloride.
The results of the January 2022 requests were submitted to the EPA
during the summer and fall of 2022. For the one facility that received
a CAA section 114 request in June 2021, the EPA has received responses
(and follow-up responses) from them in the fall and winter of 2021, and
also began receiving fenceline monitoring data for chloroprene and 1,3-
butadiene in January 2022 (and is continuing to receive this data).\21\
The EPA has used the collected information to fill data gaps, establish
the baseline emissions and control levels for purposes of the
regulatory reviews, identify the most effective control measures, and
estimate the public health and environmental and cost impacts
associated with the regulatory options considered and reflected in this
proposed action. The information not claimed as CBI by respondents is
available in the document titled Data Received From Information
Collection Request for Chemical Manufacturers, in the docket for this
action, Docket ID No. EPA-HQ-OAR-2022-0730. A list of facilities
located in the United States that are part of the SOCMI source category
with processes subject to the HON, P&R I, P&R II, and/or the SOCMI NSPS
(40 CFR part 60, subparts VVa, III, NNN, and RRR), 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, in the docket for this action, Docket ID No. EPA-HQ-OAR-
2022-0730.
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\21\ As fenceline monitoring data continues to be gathered for
this facility, it is being posted on the following web page: https://www.epa.gov/la/denka-air-monitoring-data-summaries.
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D. What other relevant background information and data are available?
As mentioned above, today's action includes proposed amendments to
the current flare requirements in the SOCMI NSPS for air oxidation
reactors, distillation columns, and reactor processes, and NESHAP for
the HON and P&R I. In proposing these amendments, we relied on certain
technical reports and memoranda that the EPA developed for flares used
as APCDs in the Petroleum Refinery Sector residual risk and technology
review and NSPS rulemaking (80 FR 75178, December 1, 2015). The
Petroleum Refinery sector docket is at Docket ID No. EPA-HQ-OAR-2010-
0682. For completeness of the rulemaking record for today's action and
for ease of reference in finding these items in the publicly available
petroleum refinery sector rulemaking docket, we are including the most
relevant flare related technical support documents in the docket for
this proposed action (Docket ID No. EPA-HQ-OAR-2022-0730) and including
a list of all documents used to inform the 2015 flare provisions in the
Petroleum Refinery Sector residual risk and technology review and NSPS
rulemaking in the document titled Control Option Impacts for Flares
Located in the SOCMI Source Category
[[Page 25095]]
that Control Emissions from Processes Subject to HON and for Flares
that Control Emissions from Processes Subject to Group I and Group II
Polymers and Resins NESHAPs, which is available in the docket for this
rulemaking.
We are also relying on data gathered to support the RTRs for the
EMACT standards, MON, and OLD NESHAP, as well as memoranda documenting
the technology reviews for those processes. Many of the emission
sources for ethylene production facilities, MON facilities, and OLD
facilities are similar to HON, P&R I, and P&R II facilities, and
several of the control options analyzed for the HON, and P&R I and P&R
II, were also analyzed for the RTRs for the EMACT standards, MON, and
OLD NESHAP. The memoranda and background technical information can be
found in the Ethylene Production RTR rulemaking docket, Docket ID No.
EPA-HQ-OAR-2017-0357; the MON RTR rulemaking docket, Docket ID No. EPA-
HQ-OAR-2018-0746; and the OLD RTR rulemaking docket, Docket ID No. EPA-
HQ-OAR-2018-0074.
Additional information related to the promulgation and subsequent
amendments of the NSPS subparts VVa, III, NNN, and RRR, the HON, and
P&R I and P&R II is available in Docket ID Nos. A-80-25, A-81-22, A-83-
29, A-90-19, EPA-HQ-OAR-2002-0026, EPA-HQ-OAR-2002-0281, EPA-HQ-OAR-
2002-0284, EPA-HQ-OAR-2002-0475, EPA-HQ-OAR-2006-0699, EPA-HQ-OAR-2007-
0211, and EPA-HQ-OAR-2010-0600.
Lastly, the EPA acknowledges that there is also some unique ambient
community monitoring data available for chloroprene concentrations near
the Neoprene Production facility that was developed since 2016
separately from this rulemaking process.\22\ This unique ambient
community monitoring data includes data gathered by the EPA and the
Louisiana Department of Environmental Quality and consists of short-
term, 24-hour cannister sampling data gathered over various days
throughout a four-year period both before and after the Neoprene
Production facility installed controls to reduce emissions of
chloroprene. The data generally indicate that concentrations in the
community have decreased over time, but the current levels corroborate
the need for further reductions.
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\22\ https://www.epa.gov/la/denka-air-monitoring-data-summaries.
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Consistent with our usual practice in developing proposed rules
under CAA section 112(f)(2), the EPA has conducted its risk assessment
based on modeling of current allowable and/or actual emissions and
projected future emissions. The EPA has not relied on the unique
ambient community monitoring data for the Neoprene Production facility:
(1) In assessing the remaining risk from chloroprene emissions from the
SOCMI or Neoprene Production source categories after compliance with
existing emission standards or (2) in projecting future risks that
would remain after compliance with the proposed standards here.
Consequently, the unique ambient community monitoring data is not part
of our rulemaking record.
The EPA relies on modeling, which is not dependent on the
availability (or lack thereof) of monitoring data, to perform our risk
assessments when developing residual risk analyses under CAA section
112(f)(2). Modeling provides the EPA with the ability and flexibility
to estimate risks for all populations living near the sources across an
impacted industrial source category, and to estimate various risk
metrics, such as the MIR, cancer incidence, and number of people above
specific risk thresholds. Modeling also allows the EPA to assess the
risks that will remain after the implementation of proposed controls.
With these caveats in mind, the EPA seeks comment on the relevance (if
any) of the unique ambient community monitoring data to the EPA's
rulemaking.
E. How do we consider risk in our decision-making?
As discussed in section II.A.1 of this preamble and in the 1989
Benzene NESHAP, in evaluating and developing standards under CAA
section 112(f)(2), our longstanding and consistent policy is that we
apply a two-step approach to determine whether or not risks are
acceptable and to determine if the standards provide an ample margin of
safety to protect public health. As explained in the 1989 Benzene
NESHAP, ``the first step judgment on acceptability cannot be reduced to
any single factor'' and, thus, ``[t]he Administrator believes that the
acceptability of risk under section 112 is best judged on the basis of
a broad set of health risk measures and information.'' (54 FR 38046).
Similarly, with regard to the ample margin of safety determination,
``the Agency again considers all of the health risk and other health
information considered in the first step. Beyond that information,
additional factors relating to the appropriate level of control will
also be considered, including cost and economic impacts of controls,
technological feasibility, uncertainties, and any other relevant
factors.'' Id.
The 1989 Benzene NESHAP approach provides flexibility regarding
factors the EPA may consider in making determinations and how the EPA
may weigh those factors for each source category. The EPA conducts a
risk assessment that provides estimates of the MIR posed by emissions
of HAP that are carcinogens from each source in the source category,
the hazard index (HI) for chronic exposures to HAP with the potential
to cause noncancer health effects, and the hazard quotient (HQ) for
acute exposures to HAP with the potential to cause noncancer health
effects.\23\ The assessment also provides estimates of the distribution
of cancer risk within the exposed populations, cancer incidence, and an
evaluation of the potential for an adverse environmental effect. The
scope of the EPA's risk analysis is consistent with the explanation in
EPA's response to comments on our policy under the 1989 Benzene NESHAP:
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\23\ The MIR is defined as the cancer risk associated with a
lifetime of exposure at the highest concentration of HAP where
people are likely to live. The HQ is the ratio of the potential HAP
exposure concentration to the noncancer dose-response value; the HI
is the sum of HQs for HAP that affect the same target organ or organ
system.
The policy chosen by the Administrator permits consideration of
multiple measures of health risk. Not only can the MIR figure be
considered, but also incidence, the presence of non-cancer health
effects, and the uncertainties of the risk estimates. In this way,
the effect on the most exposed individuals can be reviewed as well
as the impact on the general public. These factors can then be
weighed in each individual case. This approach complies with the
Vinyl Chloride mandate that the Administrator ascertain an
acceptable level of risk to the public by employing his expertise to
assess available data. It also complies with the Congressional
intent behind the CAA, which did not exclude the use of any
particular measure of public health risk from the EPA's
consideration with respect to CAA section 112 regulations, and
thereby implicitly permits consideration of any and all measures of
health risk which the Administrator, in his judgment, believes are
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appropriate to determining what will ``protect the public health''.
(54 FR 38057). Thus, the level of the MIR is only one factor to be
weighed in determining acceptability of risk. The 1989 Benzene NESHAP
explained that ``an MIR of approximately one in 10 thousand should
ordinarily be the upper end of the range of acceptability. As risks
increase above this benchmark, they become presumptively less
acceptable under CAA section 112, and would be weighed with the other
health
[[Page 25096]]
risk measures and information in making an overall judgment on
acceptability. Or, the Agency may find, in a particular case, that a
risk that includes an MIR less than the presumptively acceptable level
is unacceptable in the light of other health risk factors.'' Id. at
38045. In other words, risks that include an MIR above 100-in-1 million
may be determined to be acceptable, and risks with an MIR below that
level may be determined to be unacceptable, depending on all of the
available health information. Similarly, with regard to the ample
margin of safety analysis, the EPA stated in the 1989 Benzene NESHAP
that: ``EPA believes the relative weight of the many factors that can
be considered in selecting an ample margin of safety can only be
determined for each specific source category. This occurs mainly
because technological and economic factors (along with the health-
related factors) vary from source category to source category.'' Id. at
38061. We also consider the uncertainties associated with the various
risk analyses, as discussed earlier in this preamble, in our
determinations of acceptability and ample margin of safety.
The EPA notes that it has not considered certain health information
to date in making residual risk determinations. At this time, we do not
attempt to quantify the HAP risk that may be associated with emissions
from other facilities that do not include the source category under
review, mobile source emissions, natural source emissions, persistent
environmental pollution, or atmospheric transformation in the vicinity
of the sources in the category.
The EPA understands the potential importance of considering an
individual's total exposure to HAP in addition to considering exposure
to HAP emissions from the source category and facility. We recognize
that such consideration may be particularly important when assessing
noncancer risk, where pollutant-specific exposure health reference
levels (e.g., reference concentrations (RfCs)) are based on the
assumption that thresholds exist for adverse health effects. For
example, the EPA recognizes that, although exposures attributable to
emissions from a source category or facility alone may not indicate the
potential for increased risk of adverse noncancer health effects in a
population, the exposures resulting from emissions from the facility in
combination with emissions from all of the other sources (e.g., other
facilities) to which an individual is exposed may be sufficient to
result in an increased risk of adverse noncancer health effects. In May
2010, the Science Advisory Board (SAB) advised the EPA ``that RTR
assessments will be most useful to decision makers and communities if
results are presented in the broader context of aggregate and
cumulative risks, including background concentrations and contributions
from other sources in the area.'' \24\
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\24\ Recommendations of the SAB Risk and Technology Review
Methods Panel are provided in their report, which is available at:
https://www.epa.gov/sites/default/files/2021-02/documents/epa-sab-10-007-unsigned.pdf.
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In response to the SAB recommendations, the EPA incorporates
cumulative risk analyses into its RTR risk assessments. The Agency: (1)
Conducts facility-wide assessments, which include source category
emission points, as well as other emission points within the
facilities; (2) combines exposures from multiple sources in the same
category that could affect the same individuals; and (3) for some
persistent and bioaccumulative pollutants, analyzes the ingestion route
of exposure. In addition, the RTR risk assessments consider aggregate
cancer risk from all carcinogens and aggregated noncancer HQs for all
noncarcinogens affecting the same target organ or target organ system.
Although we are interested in placing source category and facility-
wide HAP risk in the context of total HAP risk from all sources
combined in the vicinity of each source, we note there are
uncertainties of doing so. Estimates of total HAP risk from emission
sources other than those that we have studied in depth during this RTR
review would have significantly greater associated uncertainties than
the source category or facility-wide estimates.
F. How do we estimate post-MACT risk posed by the source category?
In this section, we provide a complete description of the types of
analyses that we generally perform during the risk assessment process.
In some cases, we do not perform a specific analysis because it is not
relevant. For example, in the absence of emissions of HAP known to be
persistent and bioaccumulative in the environment (PB-HAP), we would
not perform a multipathway exposure assessment. Where we do not perform
an analysis, we state that we do not and provide the reason. While we
present all of our risk assessment methods, we only present risk
assessment results for the analyses actually conducted (see section
III.B of this preamble).
The EPA conducts a risk assessment that provides estimates of the
MIR for cancer posed by the HAP emissions from each source in the
source category, the HI for chronic exposures to HAP with the potential
to cause noncancer health effects, and the HQ for acute exposures to
HAP with the potential to cause noncancer health effects. The
assessment also provides estimates of the distribution of cancer risk
within the exposed populations, cancer incidence, and an evaluation of
the potential for an adverse environmental effect. The eight sections
that follow this paragraph describe how we estimated emissions and
conducted the risk assessment. The docket for this rulemaking contains
the following documents which provide more information on the risk
assessment inputs and models: Residual Risk Assessment for the SOCMI
Source Category in Support of the 2023 Risk and Technology Review
Proposed Rule and Residual Risk Assessment for the Polymers & Resins I
Neoprene Production Source Category in Support of the 2023 Risk and
Technology Review Proposed Rule. The methods used to assess risk (as
described in the eight primary steps below) are consistent with those
described by the EPA in the document reviewed by a panel of the EPA's
SAB in 2009; \25\ and described in the SAB review report issued in
2010. They are also consistent with the key recommendations contained
in that report.
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\25\ U.S. EPA. Risk and Technology Review (RTR) Risk Assessment
Methodologies: For Review by the EPA's Science Advisory Board with
Case Studies--MACT I Petroleum Refining Sources and Portland Cement
Manufacturing, June 2009. EPA-452/R-09-006. https://www3.epa.gov/airtoxics/rrisk/rtrpg.html.
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1. How did we estimate actual emissions and identify the emissions
release characteristics?
As previously discussed, we updated the risk assessment in this
action for the SOCMI and Neoprene Production source categories because
these source categories have sources that emit EtO and/or chloroprene.
The SOCMI and Neoprene Production source category facility lists were
developed as described in section II.C of this preamble and consist of
207 HON facilities and one neoprene production facility.\26\ For the
207 HON facilities, only 195 had reported HAP emissions in the 2017
NEI, and we note that two facilities included in the 207 are new/under
construction and were not operating in 2017. The emissions modeling
input files were developed using the EPA's 2017 NEI. However, in a few
instances where facility-specific
[[Page 25097]]
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 2018 NEI). 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. For further details on the
assumptions and methodologies used to estimate actual emissions, see
Appendix 1 of the document titled Residual Risk Assessment for the
SOCMI Source Category in Support of the 2023 Risk and Technology Review
Proposed Rule, which is available in the docket for this rulemaking.
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\26\ The one neoprene production facility also has collocated
HON emissions sources from the production of chloroprene.
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2. How did we estimate MACT-allowable emissions?
The available emissions data in the RTR emissions dataset include
estimates of the mass of HAP emitted during a specified annual time
period. These ``actual'' emission levels are often lower than the
emission levels allowed under the requirements of the current MACT
standards. The emissions allowed under the MACT standards are referred
to as the ``MACT-allowable'' emissions. We discussed the consideration
of both MACT-allowable and actual emissions in the final Coke Oven
Batteries RTR (70 FR 19992, 19998-19999, April 15, 2005) and in the
proposed and final HON RTR (71 FR 34421, 34428, June 14, 2006, and 71
FR 76603, 76609, December 21, 2006, respectively). In those actions, we
noted that assessing the risk at the MACT-allowable level is inherently
reasonable since that risk reflects the maximum level facilities could
emit and still comply with national emission standards. We also
explained that it is reasonable to consider actual emissions, where
such data are available, in both steps of the risk analysis, in
accordance with the 1989 Benzene NESHAP approach. (54 FR 38044.)
For this analysis, we have determined that the actual emissions
data are reasonable estimates of the MACT-allowable emissions levels
for the SOCMI source category, as we are not generally aware of any
situations in which a facility is conducting additional work practices
or operating a control device such that it achieves a far greater
emission reduction than required by the NESHAP. For the Neoprene
Production source category, we do know that some emission sources
(e.g., process vents) are being controlled beyond the current level of
the NESHAP standards. However, because there is only one facility in
the source category and because we are proposing to require these same
control requirements in this action, we consider these to be part of
the baseline actual emissions. We are also not aware of the neoprene
production facility over-controlling fugitive emission sources, which
tend to be the predominant risk drivers for this source category. We
note that because of the difficulty and uncertainty around comparing
fugitive emissions reported in emission inventories (i.e., assumptions
and engineering calculations are generally used for fugitive emissions
in emissions inventories since it is not practicable to measure them
due to technological and economic limitations) to the MACT standards
for both the SOCMI and Neoprene Production source categories and
whether facilities are better controlling these emissions sources since
they tend to drive risks, a separate assessment of risk for allowable
emissions appears unnecessary given the finding that risks are
unacceptable based on actual emissions (see section III.B of this
preamble). For further details on the assumptions and methodologies
used to estimate MACT-allowable emissions, see Appendix 1 of the
document titled Residual Risk Assessment for the SOCMI Source Category
in Support of the 2023 Risk and Technology Review Proposed Rule, which
is available in the docket for this rulemaking.
3. How do we conduct dispersion modeling, determine inhalation
exposures, and estimate individual and population inhalation risk?
Both long-term and short-term inhalation exposure concentrations
and health risk from the source category addressed in this proposal
were estimated using the Human Exposure Model (HEM).\27\ The HEM
performs three primary risk assessment activities: (1) Conducting
dispersion modeling to estimate the concentrations of HAP in ambient
air, (2) estimating long-term and short-term inhalation exposures to
individuals residing within 50 kilometers (km) (~31 miles) of the
modeled sources, and (3) estimating individual and population-level
inhalation risk using the exposure estimates and quantitative dose-
response information.
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\27\ For more information about HEM, go to https://www.epa.gov/fera/risk-assessment-and-modeling-human-exposure-model-hem.
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a. Dispersion Modeling
The EPA's American Meteorological Society/EPA Regulatory Model
dispersion modeling system (AERMOD), used by the HEM, is one of the
EPA's preferred models for assessing air pollutant concentrations from
industrial facilities.\28\ To perform the dispersion modeling and to
develop the preliminary risk estimates, HEM draws on three data
libraries. The first is a library of meteorological data, which is used
for dispersion calculations. This library includes hourly surface and
upper air observations for years ranging from 2016-2019 from over 800
meteorological stations, selected to provide coverage of the United
States and Puerto Rico. A second library of United States Census Bureau
census block \29\ internal point locations and populations provides the
basis of human exposure calculations (U.S. Census, 2010). In addition,
for each census block, the census library includes the elevation and
controlling hill height, which are also used in dispersion
calculations. A third library of pollutant-specific dose-response
values is used to estimate health risk. These are discussed below.
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\28\ U.S. EPA. Revision to the Guideline on Air Quality Models:
Adoption of a Preferred General Purpose (Flat and Complex Terrain)
Dispersion Model and Other Revisions (70 FR 68218, November 9,
2005).
\29\ A census block is the smallest geographic area for which
census statistics are tabulated.
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b. Risk From Chronic Exposure to HAP
In developing the risk assessment for chronic exposures, we use the
estimated annual average ambient air concentrations of each HAP emitted
by each source in the source category. The HAP air concentrations at
each nearby census block centroid located within 50 km (~31 miles) of
the facility are a surrogate for the chronic inhalation exposure
concentration for all the people who reside in that census block. A
distance of 50 km is consistent with both the analysis supporting the
1989 Benzene NESHAP (54 FR 38044) and the limitations of Gaussian
dispersion models, including AERMOD.
For each facility, we calculate the MIR as the cancer risk
associated with a continuous lifetime (24 hours per day, 7 days per
week, 52 weeks per year, 70 years) exposure to the maximum
concentration at the centroid of each inhabited census block. We
calculate individual cancer risk by multiplying the estimated lifetime
exposure to the
[[Page 25098]]
ambient concentration of each HAP (in micrograms per cubic meter
([mu]g/m\3\) by its URE. The URE is an upper-bound estimate of an
individual's incremental risk of contracting cancer over a lifetime of
exposure to a concentration of 1 microgram of the pollutant per cubic
meter of air. For residual risk assessments, we generally use UREs from
the EPA's IRIS. For carcinogenic pollutants without IRIS values, we
look to other reputable sources of cancer dose-response values, often
using California EPA (CalEPA) UREs, where available. In cases where
new, scientifically credible dose-response values have been developed
in a manner consistent with EPA guidelines and have undergone a peer
review process similar to that used by the EPA, we may use such dose-
response values in place of, or in addition to, other values, if
appropriate. The pollutant-specific dose-response values used to
estimate health risk are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
To estimate individual lifetime cancer risks associated with
exposure to HAP emissions from each facility in the source category, we
sum the risks for each of the carcinogenic HAP \30\ emitted by the
modeled facility. We estimate cancer risk at every census block within
50 km of every facility in the source category. The MIR is the highest
individual lifetime cancer risk estimated for any of those census
blocks. In addition to calculating the MIR, we estimate the
distribution of individual cancer risks for the source category by
summing the number of individuals within 50 km of the sources whose
estimated risk falls within a specified risk range. We also estimate
annual cancer incidence by multiplying the estimated lifetime cancer
risk at each census block by the number of people residing in that
block, summing results for all of the census blocks, and then dividing
this result by a 70-year lifetime.
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\30\ The EPA's 2005 Guidelines for Carcinogen Risk Assessment
classifies carcinogens as: ``carcinogenic to humans,'' ``likely to
be carcinogenic to humans,'' and ``suggestive evidence of
carcinogenic potential.'' These classifications also coincide with
the terms ``known carcinogen, probable carcinogen, and possible
carcinogen,'' respectively, which are the terms advocated in the
EPA's Guidelines for Carcinogen Risk Assessment, published in 1986
(51 FR 33992, September 24, 1986). In August 2000, the document,
Supplemental Guidance for Conducting Health Risk Assessment of
Chemical Mixtures (EPA/630/R-00/002), was published as a supplement
to the 1986 document. Copies of both documents can be obtained from
https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=20533&CFID=70315376&CFTOKEN=71597944. Summing
the risk of these individual compounds to obtain the cumulative
cancer risk is an approach that was recommended by the EPA's SAB in
their 2002 peer review of the EPA's National Air Toxics Assessment
(NATA) titled NATA--Evaluating the National-scale Air Toxics
Assessment 1996 Data--an SAB Advisory, available at https://
yosemite.epa.gov/sab/sabproduct.nsf/
214C6E915BB04E14852570CA007A682C/$File/ecadv02001.pdf.
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To assess the risk of noncancer health effects from chronic
exposure to HAP, we calculate either an HQ or a target organ-specific
hazard index (TOSHI). We calculate an HQ when a single noncancer HAP is
emitted. Where more than one noncancer HAP is emitted, we sum the HQ
for each of the HAP that affects a common target organ or target organ
system to obtain a TOSHI. The HQ is the estimated exposure divided by
the chronic noncancer dose-response value, which is a value selected
from one of several sources. The preferred chronic noncancer dose-
response value is the EPA RfC, defined as ``an estimate (with
uncertainty spanning perhaps an order of magnitude) of a continuous
inhalation exposure to the human population (including sensitive
subgroups) that is likely to be without an appreciable risk of
deleterious effects during a lifetime'' (https://iaspub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&vocabName=IRIS%20Glossary). In cases where an RfC
from the EPA's IRIS is not available or where the EPA determines that
using a value other than the RfC is appropriate, the chronic noncancer
dose-response value can be a value from the following prioritized
sources, which define their dose-response values similarly to the EPA:
(1) The Agency for Toxic Substances and Disease Registry (ATSDR)
Minimal Risk Level (https://www.atsdr.cdc.gov/mrls/); (2) the CalEPA
Chronic Reference Exposure Level (REL) (https://oehha.ca.gov/air/crnr/notice-adoption-air-toxics-hot-spots-program-guidance-manual-preparation-health-risk-0); or (3) as noted above, a scientifically
credible dose-response value that has been developed in a manner
consistent with the EPA guidelines and has undergone a peer review
process similar to that used by the EPA. The pollutant-specific dose-
response values used to estimate health risks are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
c. Risk From Acute Exposure to HAP That May Cause Health Effects Other
Than Cancer
For each HAP for which appropriate acute inhalation dose-response
values are available, the EPA also assesses the potential health risks
due to acute exposure. For these assessments, the EPA makes
conservative assumptions about emission rates, meteorology, and
exposure location. As part of our efforts to continually improve our
methodologies to evaluate the risks that HAP emitted from categories of
industrial sources pose to human health and the environment,\31\ we
revised our treatment of meteorological data to use reasonable worst-
case air dispersion conditions in our acute risk screening assessments
instead of worst-case air dispersion conditions. This revised treatment
of meteorological data and the supporting rationale are described in
more detail in the documents titled Residual Risk Assessment for the
SOCMI Source Category in Support of the 2023 Risk and Technology Review
Proposed Rule and Residual Risk Assessment for the Polymers & Resins I
Neoprene Production Source Category in Support of the 2023 Risk and
Technology Review Proposed Rule, and in Appendix 5 of the report:
Technical Support Document for Acute Risk Screening Assessment, which
are available in the docket for this rulemaking. This revised approach
has been used in this proposed rule and in all other RTR rulemakings
proposed on or after June 3, 2019.
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\31\ See, e.g., U.S. EPA. Screening Methodologies to Support
Risk and Technology Reviews (RTR): A Case Study Analysis (Draft
Report, May 2017. (https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html).
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To assess the potential acute risk to the maximally exposed
individual, we use the peak hourly emission rate for each emission
point,\32\ reasonable worst-case air dispersion conditions (i.e., 99th
percentile), and the point of highest off-site exposure. Specifically,
we assume that peak emissions from the source category and reasonable
worst-case air dispersion conditions co-occur
[[Page 25099]]
and that a person is present at the point of maximum exposure.
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\32\ In the absence of hourly emission data, we develop
estimates of maximum hourly emission rates by multiplying the
average actual annual emissions rates by a factor (either a
category-specific factor or a default factor of 10) to account for
variability. This is documented in 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, and in Appendix 5 of the
report: Technical Support Document for Acute Risk Screening
Assessment. All three of these documents are available in the docket
for this rulemaking.
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To characterize the potential health risks associated with
estimated acute inhalation exposures to a HAP, we generally use
multiple acute dose-response values, including acute RELs, acute
exposure guideline levels (AEGLs), and emergency response planning
guidelines (ERPG) for 1-hour exposure durations, if available, to
calculate acute HQs. The acute HQ is calculated by dividing the
estimated acute exposure concentration by the acute dose-response
value. For each HAP for which acute dose-response values are available,
the EPA calculates acute HQs.
An acute REL is defined as ``the concentration level at or below
which no adverse health effects are anticipated for a specified
exposure duration.'' \33\ Acute RELs are based on the most sensitive,
relevant, adverse health effect reported in the peer-reviewed medical
and toxicological literature. They are designed to protect the most
sensitive individuals in the population through the inclusion of
margins of safety. Because margins of safety are incorporated to
address data gaps and uncertainties, exceeding the REL does not
automatically indicate an adverse health impact. AEGLs represent
threshold exposure limits for the general public and are applicable to
emergency exposures ranging from 10 minutes to 8 hours.\34\ They are
guideline levels for ``once-in-a-lifetime, short-term exposures to
airborne concentrations of acutely toxic, high-priority chemicals.''
Id. at 21. The AEGL-1 is specifically defined as ``the airborne
concentration (expressed as ppm (parts per million) or mg/m\3\
(milligrams per cubic meter)) of a substance above which it is
predicted that the general population, including susceptible
individuals, could experience notable discomfort, irritation, or
certain asymptomatic nonsensory effects. However, the effects are not
disabling and are transient and reversible upon cessation of
exposure.'' The document also notes that ``Airborne concentrations
below AEGL-1 represent exposure levels that can produce mild and
progressively increasing but transient and nondisabling odor, taste,
and sensory irritation or certain asymptomatic, nonsensory effects.''
Id. AEGL-2 are defined as ``the airborne concentration (expressed as
parts per million or milligrams per cubic meter) of a substance above
which it is predicted that the general population, including
susceptible individuals, could experience irreversible or other
serious, long-lasting adverse health effects or an impaired ability to
escape.'' Id.
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\33\ CalEPA issues acute RELs as part of its Air Toxics Hot
Spots Program, and the 1-hour and 8-hour values are documented in
Air Toxics Hot Spots Program Risk Assessment Guidelines, Part I, The
Determination of Acute Reference Exposure Levels for Airborne
Toxicants, which is available at https://oehha.ca.gov/air/general-info/oehha-acute-8-hour-and-chronic-reference-exposure-level-rel-summary.
\34\ National Academy of Sciences, 2001. Standing Operating
Procedures for Developing Acute Exposure Levels for Hazardous
Chemicals, page 2. Available at https://www.epa.gov/sites/production/files/2015-09/documents/sop_final_standing_operating_procedures_2001.pdf. Note that the
National Advisory Committee for Acute Exposure Guideline Levels for
Hazardous Substances ended in October 2011, but the AEGL program
continues to operate at the EPA and works with the National
Academies to publish final AEGLs (https://www.epa.gov/aegl).
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ERPGs are developed, by the American Industrial Hygiene Association
(AIHA), for emergency planning and are intended to be health-based
guideline concentrations for single exposures to chemicals. The ERPG-1
is the maximum airborne concentration, established by AIHA, below which
it is believed that nearly all individuals could be exposed for up to 1
hour without experiencing other than mild transient adverse health
effects or without perceiving a clearly defined, objectionable odor.
Similarly, the ERPG-2 is the maximum airborne concentration,
established by AIHA, below which it is believed that nearly all
individuals could be exposed for up to one hour without experiencing or
developing irreversible or other serious health effects or symptoms
which could impair an individual's ability to take protective action.
An acute REL for 1-hour exposure durations is typically lower than
its corresponding AEGL-1 and ERPG-1. Even though their definitions are
slightly different, AEGL-1s are often the same as the corresponding
ERPG-1s, and AEGL-2s are often equal to ERPG-2s. The maximum HQs from
our acute inhalation screening risk assessment typically result when we
use the acute REL for a HAP. In cases where the maximum acute HQ
exceeds 1, we also report the HQ based on the next highest acute dose-
response value (usually the AEGL-1 and/or the ERPG-1).
For the SOCMI and Neoprene Production source categories, we did not
use a default acute emissions multiplier of 10, but rather, we used
process level-specific acute emissions multipliers, generally ranging
from a factor of 2 to 10 as was done in past chemical and petrochemical
residual risk reviews such as for the 2015 the Petroleum Refinery
Sector rule, 2020 MON RTR, 2020 EMACT RTR, and 2020 OLD NESHAP RTR,
where similar emission sources and standards exist. These refinements
are discussed more fully in Appendix 1 of the document titled Residual
Risk Assessment for the SOCMI Source Category in Support of the 2023
Risk and Technology Review Proposed Rule, which is available in the
docket for this rulemaking.
In our acute inhalation screening risk assessment, acute impacts
are deemed negligible for HAP for which acute HQs are less than or
equal to 1, and no further analysis is performed for these HAP. In
cases where an acute HQ from the screening step is greater than 1, we
assess the site-specific data to ensure that the acute HQ is at an off-
site location. For these source categories, the data refinements
employed consisted of reviewing satellite imagery of the locations of
the maximum acute HQ values to determine if the maximum was off
facility property. For any maximum value that was determined to be on
facility property, the next highest value that was off facility
property was used. These refinements are discussed more fully in the
documents titled Residual Risk Assessment for the SOCMI Source Category
in Support of the 2023 Risk and Technology Review Proposed Rule and
Residual Risk Assessment for the Polymers & Resins I Neoprene
Production Source Category in Support of the 2023 Risk and Technology
Review Proposed Rule, which are available in the docket for this
rulemaking.
4. How do we conduct the multipathway exposure and risk screening
assessment?
The EPA conducts a tiered screening assessment examining the
potential for significant human health risks due to exposures via
routes other than inhalation (i.e., ingestion). We first determine
whether any sources in the source categories emit any HAP known to be
persistent and bioaccumulative in the environment, as identified in the
EPA's Air Toxics Risk Assessment Library (see Volume 1, Appendix D, at
https://www.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library).
For the Neoprene Production source category, we did not identify
emissions of any PB-HAP in the reported emissions inventory. Because we
did not identify reported PB-HAP emissions, we could not undertake the
three-tier human health risk screening assessment of PB-HAP that we
discuss below and which was conducted for the SOCMI source category.
However, for dioxins we used the results of the SOCMI source category
human health screening assessment at facilities with higher dioxin
emission rates than the
[[Page 25100]]
ones proposed for the Neoprene Production source category to
qualitatively assess the potential for human health risks.
For the SOCMI source category, we identified PB-HAP emissions of
arsenic compounds, cadmium compounds, dioxins, polycyclic organic
matter (POM), and mercury, so we proceeded to the next step of the
evaluation. Except for lead, the human health risk screening assessment
for PB-HAP consists of three progressive tiers. In a Tier 1 screening
assessment, we determine whether the magnitude of the facility-specific
emissions of PB-HAP warrants further evaluation to characterize human
health risk through ingestion exposure. To facilitate this step, we
evaluate emissions against previously developed screening threshold
emission rates for several PB-HAP that are based on a hypothetical
upper-end screening exposure scenario developed for use in conjunction
with the EPA's Total Risk Integrated Methodology.Fate, Transport, and
Ecological Exposure (TRIM.FaTE) model. The PB-HAP with screening
threshold emission rates are arsenic compounds, cadmium compounds,
chlorinated dibenzodioxins and furans, mercury compounds, and POM.
Based on the EPA estimates of toxicity and bioaccumulation potential,
these pollutants represent a conservative list for inclusion in
multipathway risk assessments for RTR rules. (See Volume 1, Appendix D
at https://www.epa.gov/sites/production/files/2013-08/documents/volume_1_reflibrary.pdf.) In this assessment, we compare the facility-
specific emission rates of these PB-HAP to the screening threshold
emission rates for each PB-HAP to assess the potential for significant
human health risks via the ingestion pathway. We call this application
of the TRIM.FaTE model the Tier 1 screening assessment. The ratio of a
facility's actual emission rate to the Tier 1 screening threshold
emission rate is a ``screening value.''
We derive the Tier 1 screening threshold emission rates for these
PB-HAP (other than lead compounds) to correspond to a maximum excess
lifetime cancer risk of 1-in-1 million (i.e., for arsenic compounds,
polychlorinated dibenzodioxins and furans, and POM) or, for HAP that
cause noncancer health effects (i.e., cadmium compounds and mercury
compounds), a maximum HQ of 1. If the emission rate of any one PB-HAP
or combination of carcinogenic PB-HAP in the Tier 1 screening
assessment exceeds the Tier 1 screening threshold emission rate for any
facility (i.e., the screening value is greater than 1), we conduct a
second screening assessment, which we call the Tier 2 screening
assessment. The Tier 2 screening assessment separates the Tier 1
combined fisher and farmer exposure scenario into fisher, farmer, and
gardener scenarios that retain upper-bound ingestion rates.
In the Tier 2 screening assessment, the location of each facility
that exceeds a Tier 1 screening threshold emission rate is used to
refine the assumptions associated with the Tier 1 fisher and farmer
exposure scenarios at that facility. A key assumption in the Tier 1
screening assessment is that a lake and/or farm is located near the
facility. As part of the Tier 2 screening assessment, we use a U.S.
Geological Survey (USGS) database to identify actual waterbodies within
50 km (~31 miles) of each facility and assume the fisher only consumes
fish from lakes within that 50 km zone. We also examine the differences
between local meteorology near the facility and the meteorology used in
the Tier 1 screening assessment. We then adjust the previously-
developed Tier 1 screening threshold emission rates for each PB-HAP for
each facility based on an understanding of how exposure concentrations
estimated for the screening scenario change with the use of local
meteorology and the USGS lakes database.
In the Tier 2 farmer scenario, we maintain an assumption that the
farm is located within 0.5 km (~0.3 miles) of the facility and that the
farmer consumes meat, eggs, dairy, vegetables, and fruit produced near
the facility. We may further refine the Tier 2 screening analysis by
assessing a gardener scenario to characterize a range of exposures,
with the gardener scenario being more plausible in RTR evaluations.
Under the gardener scenario, we assume the gardener consumes home-
produced eggs, vegetables, and fruit products at the same ingestion
rate as the farmer. The Tier 2 screen continues to rely on the high-end
food intake assumptions that were applied in Tier 1 for local fish
(adult female angler at 99th percentile fish consumption \35\) and
locally grown or raised foods (90th percentile consumption of locally
grown or raised foods for the farmer and gardener scenarios \36\). If
PB-HAP emission rates do not result in a Tier 2 screening value greater
than 1, we consider those PB-HAP emissions to pose risks below a level
of concern. If the PB-HAP emission rates for a facility exceed the Tier
2 screening threshold emission rates, we may conduct a Tier 3 screening
assessment.
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\35\ Burger, J. 2002. Daily consumption of wild fish and game:
Exposures of high end recreationists. International Journal of
Environmental Health Research, 12:343-354.
\36\ U.S. EPA. Exposure Factors Handbook 2011 Edition (Final).
U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/
052F, 2011.
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There are several analyses that can be included in a Tier 3
screening assessment, depending upon the extent of refinement
warranted, including validating that the lakes are fishable, locating
residential/garden locations for urban and/or rural settings,
considering plume-rise to estimate emissions lost above the mixing
layer, and considering hourly effects of meteorology and plume-rise on
chemical fate and transport (a time-series analysis). If necessary, the
EPA may further refine the screening assessment through a site-specific
assessment.
In evaluating the potential multipathway risk from emissions of
lead compounds, rather than developing a screening threshold emission
rate, we compare maximum estimated chronic inhalation exposure
concentrations to the level of the current National Ambient Air Quality
Standard (NAAQS) for lead.\37\ Values below the level of the primary
(health-based) lead NAAQS are considered to have a low potential for
multipathway risk.
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\37\ In doing so, the EPA notes that the legal standard for a
primary NAAQS--that a standard is requisite to protect public health
and provide an adequate margin of safety (CAA section 109(b))--
differs from the CAA section 112(f) standard (requiring, among other
things, that the standard provide an ``ample margin of safety to
protect public health''). However, the primary lead NAAQS is a
reasonable measure of determining risk acceptability (i.e., the
first step of the 1989 Benzene NESHAP analysis) since it is designed
to protect the most susceptible group in the human population--
children, including children living near major lead emitting
sources. 73 FR 67002/3; 73 FR 67000/3; 73 FR 67005/1. In addition,
applying the level of the primary lead NAAQS at the risk
acceptability step is conservative, since that primary lead NAAQS
reflects an adequate margin of safety.
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For further information on the multipathway assessment approach,
see the documents titled Residual Risk Assessment for the SOCMI Source
Category in Support of the 2023 Risk and Technology Review Proposed
Rule and Residual Risk Assessment for the Polymers & Resins I Neoprene
Production Source Category in Support of the 2023 Risk and Technology
Review Proposed Rule, which are available in the docket for this
rulemaking.
5. How do we assess risks considering emissions control options?
In addition to assessing baseline inhalation risks and screening
for potential multipathway risks, we also estimate risks considering
the potential
[[Page 25101]]
emission reductions that would be achieved by the control options under
consideration. In these cases, the expected emission reductions are
applied to the specific HAP and emission points in the RTR emissions
dataset to develop corresponding estimates of risk and incremental risk
reductions.
6. How do we conduct the environmental risk screening assessment?
a. Adverse Environmental Effect, Environmental HAP, and Ecological
Benchmarks
The EPA conducts a screening assessment to examine the potential
for an adverse environmental effect as required under section
112(f)(2)(A) of the CAA. Section 112(a)(7) of the CAA defines ``adverse
environmental effect'' as ``any significant and widespread adverse
effect, which may reasonably be anticipated, to wildlife, aquatic life,
or other natural resources, including adverse impacts on populations of
endangered or threatened species or significant degradation of
environmental quality over broad areas.''
The EPA focuses on eight HAP, which are referred to as
``environmental HAP,'' in its screening assessment: six PB-HAP and two
acid gases. The PB-HAP included in the screening assessment are arsenic
compounds, cadmium compounds, dioxins/furans, POM, mercury (both
inorganic mercury and methyl mercury), and lead compounds. The acid
gases included in the screening assessment are hydrochloric acid (HCl)
and hydrofluoric acid (HF).
HAP that persist and bioaccumulate are of particular environmental
concern because they accumulate in the soil, sediment, and water. The
acid gases, HCl and HF, are included due to their well-documented
potential to cause direct damage to terrestrial plants. In the
environmental risk screening assessment, we evaluate the following four
exposure media: terrestrial soils, surface water bodies (includes
water-column and benthic sediments), fish consumed by wildlife, and
air. Within these four exposure media, we evaluate nine ecological
assessment endpoints, which are defined by the ecological entity and
its attributes. For PB-HAP (other than lead), both community-level and
population-level endpoints are included. For acid gases, the ecological
assessment evaluated is terrestrial plant communities.
An ecological benchmark represents a concentration of HAP that has
been linked to a particular environmental effect level. For each
environmental HAP, we identified the available ecological benchmarks
for each assessment endpoint. We identified, where possible, ecological
benchmarks at the following effect levels: probable effect levels,
lowest-observed-adverse-effect level, and no-observed-adverse-effect
level. In cases where multiple effect levels were available for a
particular PB-HAP and assessment endpoint, we use all of the available
effect levels to help us to determine whether ecological risks exist
and, if so, whether the risks could be considered significant and
widespread.
For further information on how the environmental risk screening
assessment was conducted, including a discussion of the risk metrics
used, how the environmental HAP were identified, and how the ecological
benchmarks were selected, see Appendix 9 of the documents titled
Residual Risk Assessment for the SOCMI Source Category in Support of
the 2023 Risk and Technology Review Proposed Rule and Residual Risk
Assessment for the Polymers & Resins I Neoprene Production Source
Category in Support of the 2023 Risk and Technology Review Proposed
Rule, which are available in the docket for this rulemaking.
b. Environmental Risk Screening Methodology
For the environmental risk screening assessment, the EPA first
determined whether any facilities in the SOCMI and Neoprene Production
source categories emitted any of the environmental HAP. For the
Neoprene Production source category, we did not identify reported
emissions of any of the six environmental HAP included in the screen.
Because we did not identify reported environmental HAP emissions from
the neoprene source category, we could not proceed to the second step
of the evaluation as discussed below for the HON. However, for dioxins
we used the results of the SOCMI source category environmental risk
screening assessment at facilities with higher dioxin emission rates
than the ones proposed for the Neoprene Production source category to
qualitative assess the potential for adverse environmental effects.
For the SOCMI source category, we identified reported emissions of
arsenic compounds, cadmium compounds, dioxins, POM, and mercury.\38\
Because one or more of the environmental HAP evaluated are emitted by
at least one facility in the SOCMI source category, we proceeded to the
second step of the evaluation.
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\38\ We note that in many instances, we did not have sufficient
information to parse out emissions from HON processes from facility-
wide emissions inventories, thus we took a conservative approach and
modeled facility-wide emissions as if they were all from the SOCMI
source category.
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c. PB-HAP Methodology
The environmental screening assessment includes six PB-HAP, arsenic
compounds, cadmium compounds, dioxins/furans, POM, mercury (both
inorganic mercury and methyl mercury), and lead compounds. With the
exception of lead, the environmental risk screening assessment for PB-
HAP consists of three tiers. The first tier of the environmental risk
screening assessment uses the same health-protective conceptual model
that is used for the Tier 1 human health screening assessment.
TRIM.FaTE model simulations were used to back-calculate Tier 1
screening threshold emission rates. The screening threshold emission
rates represent the emission rate in tons of pollutant per year that
results in media concentrations at the facility that equal the relevant
ecological benchmark. To assess emissions from each facility in the
category, the reported emission rate for each PB-HAP was compared to
the Tier 1 screening threshold emission rate for that PB-HAP for each
assessment endpoint and effect level. If emissions from a facility do
not exceed the Tier 1 screening threshold emission rate, the facility
``passes'' the screening assessment, and, therefore, is not evaluated
further under the screening approach. If emissions from a facility
exceed the Tier 1 screening threshold emission rate, we evaluate the
facility further in Tier 2.
In Tier 2 of the environmental screening assessment, the screening
threshold emission rates are adjusted to account for local meteorology
and the actual location of lakes in the vicinity of facilities that did
not pass the Tier 1 screening assessment. For soils, we evaluate the
average soil concentration for all soil parcels within a 7.5-km radius
for each facility and PB-HAP. For the water, sediment, and fish tissue
concentrations, the highest value for each facility for each pollutant
is used. If emission concentrations from a facility do not exceed the
Tier 2 screening threshold emission rate, the facility ``passes'' the
screening assessment and typically is not evaluated further. If
emissions from a facility exceed the Tier 2 screening threshold
emission rate, we evaluate the facility further in Tier 3.
As in the multipathway human health risk assessment, in Tier 3 of
the environmental screening assessment, we examine the suitability of
the lakes
[[Page 25102]]
around the facilities to support life and remove those that are not
suitable (e.g., lakes that have been filled in or are industrial
ponds), adjust emissions for plume-rise, and conduct hour-by-hour time-
series assessments. If these Tier 3 adjustments to the screening
threshold emission rates still indicate the potential for an adverse
environmental effect (i.e., facility emission rate exceeds the
screening threshold emission rate), we may elect to conduct a more
refined assessment using more site-specific information. If, after
additional refinement, the facility emission rate still exceeds the
screening threshold emission rate, the facility may have the potential
to cause an adverse environmental effect.
To evaluate the potential for an adverse environmental effect from
lead, we compared the average modeled air concentrations (from HEM-3)
of lead around each facility in the source category to the level of the
secondary NAAQS for lead. The secondary lead NAAQS is a reasonable
means of evaluating environmental risk because it is set to provide
substantial protection against adverse welfare effects which can
include ``effects on soils, water, crops, vegetation, man-made
materials, animals, wildlife, weather, visibility and climate, damage
to and deterioration of property, and hazards to transportation, as
well as effects on economic values and on personal comfort and well-
being.''
d. Acid Gas Environmental Risk Methodology
The environmental screening assessment for acid gases evaluates the
potential phytotoxicity and reduced productivity of plants due to
chronic exposure to HF and HCl. The environmental risk screening
methodology for acid gases is a single-tier screening assessment that
compares modeled ambient air concentrations (from AERMOD) to the
ecological benchmarks for each acid gas. To identify a potential
adverse environmental effect (as defined in section 112(a)(7) of the
CAA) from emissions of HF and HCl, we evaluate the following metrics:
the size of the modeled area around each facility that exceeds the
ecological benchmark for each acid gas, in acres and square km; the
percentage of the modeled area around each facility that exceeds the
ecological benchmark for each acid gas; and the area-weighted average
screening value around each facility (calculated by dividing the area-
weighted average concentration over the 50-km modeling domain by the
ecological benchmark for each acid gas). For further information on the
environmental screening assessment approach, see Appendix 9 of the
documents titled Residual Risk Assessment for the SOCMI Source Category
in Support of the 2023 Risk and Technology Review Proposed Rule and
Residual Risk Assessment for the Polymers & Resins I Neoprene
Production Source Category in Support of the 2023 Risk and Technology
Review Proposed Rule, which are available in the docket for this
rulemaking.
7. How do we conduct facility-wide assessments?
To put the source category risks in context, we typically examine
the risks from the entire ``facility,'' where the facility includes all
HAP-emitting operations within a contiguous area and under common
control. In other words, we examine the HAP emissions not only from the
source category emission points of interest, but also emissions of HAP
from all other emission sources at the facility for which we have data.
For these source categories, we conducted the facility-wide assessment
using a dataset compiled from the 2017 NEI and other emissions
information discussed in section II.C of this preamble. Once a quality
assured source category dataset was available, it was placed back with
the remaining records from the emissions inventory for that facility
(which in most instances was 2017 NEI data). The facility-wide file was
then used to analyze risks due to the inhalation of HAP that are
emitted ``facility-wide'' for the populations residing within 50 km
(~31 miles) of each facility, consistent with the methods used for the
source category analysis described above. For these facility-wide risk
analyses, the modeled source category risks were compared to the
facility-wide risks to determine the portion of the facility-wide risks
that could be attributed to the source category addressed in this
proposal. We also specifically examined the facility that was
associated with the highest estimate of risk and determined the
percentage of that risk attributable to the source category of
interest. The documents titled Residual Risk Assessment for the SOCMI
Source Category in Support of the 2023 Risk and Technology Review
Proposed Rule and Residual Risk Assessment for the Polymers & Resins I
Neoprene Production Source Category in Support of the 2023 Risk and
Technology Review Proposed Rule, available through the docket for this
rulemaking, provide the methodology and results of the facility-wide
analyses, including all facility-wide risks and the percentage of
source category contribution to facility-wide risks.
8. How do we conduct community-based risk assessments?
In addition to the source category and facility-wide risk
assessments, we also assessed the combined inhalation cancer risk from
all local stationary sources of HAP for which we have emissions data.
Specifically, we combined the modeled impacts from the facility-wide
assessment (which includes category and non-category sources) with
other nearby stationary point source model results. The facility-wide
emissions used in this assessment are discussed in section II.C of this
preamble. For the other nearby point sources, we used AERMOD model
results with emissions based primarily on the 2018 NEI. After combining
these model results, we assessed cancer risks due to the inhalation of
all HAP emitted by point sources for the populations residing within 10
km (~6.2 miles) of HON facilities. In the community-based risk
assessment, the modeled source category and facility-wide cancer risks
were compared to the cancer risks from other nearby point sources to
determine the portion of the risks that could be attributed to the
source category addressed in this proposal. The document titled
Residual Risk Assessment for the SOCMI Source Category in Support of
the 2023 Risk and Technology Review Proposed Rule, which is available
in the docket for this rulemaking, provides the methodology and results
of the community-based risks analyses.
9. How do we consider uncertainties in risk assessment?
Uncertainty and the potential for bias are inherent in all risk
assessments, including those performed for this proposal. Although
uncertainty exists, we believe that our approach, which used
conservative tools and assumptions, ensures that our decisions are
health and environmentally protective. A brief discussion of the
uncertainties in the RTR emissions datasets, dispersion modeling,
inhalation exposure estimates, and dose-response relationships follows
below. Also included are those uncertainties specific to our acute
screening assessments, multipathway screening assessments, and our
environmental risk screening assessments. A more thorough discussion of
these uncertainties is included in the documents titled Residual Risk
Assessment for the SOCMI Source Category in Support of the 2023 Risk
and Technology Review
[[Page 25103]]
Proposed Rule and Residual Risk Assessment for the Polymers & Resins I
Neoprene Production Source Category in Support of the 2023 Risk and
Technology Review Proposed Rule, which are available in the docket for
this rulemaking. If a multipathway site-specific assessment was
performed for these source categories, a full discussion of the
uncertainties associated with that assessment can be found in Appendix
11 of that document, Site-Specific Human Health Multipathway Residual
Risk Assessment Report.
a. Uncertainties in the RTR Emissions Datasets
Although the development of the RTR emissions datasets involved
quality assurance/quality control processes, the accuracy of emissions
values will vary depending on the source of the data, the degree to
which data are incomplete or missing, the degree to which assumptions
made to complete the datasets are accurate, errors in emission
estimates, and other factors. The emission estimates considered in this
analysis generally are annual totals for certain years, and they do not
reflect short-term fluctuations during the course of a year or
variations from year to year. The estimates of peak hourly emission
rates for the acute effects screening assessment were based on an
emission adjustment factor applied to the average annual hourly
emission rates, which are intended to account for emission fluctuations
due to normal facility operations.
b. Uncertainties in Dispersion Modeling
We recognize there is uncertainty in ambient concentration
estimates associated with any model, including the EPA's recommended
regulatory dispersion model, AERMOD. In using a model to estimate
ambient pollutant concentrations, the user chooses certain options to
apply. For RTR assessments, we select some model options that have the
potential to overestimate ambient air concentrations (e.g., not
including plume depletion or pollutant transformation). We select other
model options that have the potential to underestimate ambient impacts
(e.g., not including building downwash). Other options that we select
have the potential to either under- or overestimate ambient levels
(e.g., meteorology and receptor locations). On balance, considering the
directional nature of the uncertainties commonly present in ambient
concentrations estimated by dispersion models, the approach we apply in
the RTR assessments should yield unbiased estimates of ambient HAP
concentrations. We also note that the selection of meteorology dataset
location could have an impact on the risk estimates. As we continue to
update and expand our library of meteorological station data used in
our risk assessments, we expect to reduce this variability.
c. Uncertainties in Inhalation Exposure Assessment
Although every effort is made to identify all of the relevant
facilities and emission points, as well as to develop accurate
estimates of the annual emission rates for all relevant HAP, the
uncertainties in our emission inventory likely dominate the
uncertainties in the exposure assessment. Some uncertainties in our
exposure assessment include human mobility, using the centroid of each
census block, assuming lifetime exposure, and assuming only outdoor
exposures. For most of these factors, there is neither an under nor
overestimate when looking at the maximum individual risk or the
incidence, but the shape of the distribution of risks may be affected.
With respect to outdoor exposures, actual exposures may not be as high
if people spend time indoors, especially for very reactive pollutants
or larger particles. For all factors, we reduce uncertainty when
possible. For example, with respect to census-block centroids, we
analyze large blocks using aerial imagery and adjust locations of the
block centroids to better represent the population in the blocks. We
also add additional receptor locations where the population of a block
is not well represented by a single location.
d. Uncertainties in Dose-Response Relationships
There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from
chronic exposures and noncancer effects from both chronic and acute
exposures. Some uncertainties are generally expressed quantitatively,
and others are generally expressed in qualitative terms. We note, as a
preface to this discussion, a point on dose-response uncertainty that
is stated in the EPA's 2005 Guidelines for Carcinogen Risk Assessment;
namely, that ``the primary goal of EPA actions is protection of human
health; accordingly, as an Agency policy, risk assessment procedures,
including default options that are used in the absence of scientific
data to the contrary, should be health protective'''(the EPA's 2005
Guidelines for Carcinogen Risk Assessment, page 1-7). This is the
approach followed here as summarized in the next paragraphs.
Cancer UREs used in our risk assessments are those that have been
developed to generally provide an upper bound estimate of risk.\39\
That is, they represent a ``plausible upper limit to the true value of
a quantity'' (although this is usually not a true statistical
confidence limit). In some circumstances, the true risk could be as low
as zero; however, in other circumstances the risk could be greater.\40\
Chronic noncancer RfC and reference dose values represent chronic
exposure levels that are intended to be health-protective levels. To
derive dose-response values that are intended to be ``without
appreciable risk,'' the methodology relies upon an uncertainty factor
(UF) approach,\41\ which considers uncertainty, variability, and gaps
in the available data. The UFs are applied to derive dose-response
values that are intended to protect against appreciable risk of
deleterious effects.
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\39\ IRIS glossary (https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary).
\40\ An exception to this is the URE for benzene, which is
considered to cover a range of values, each end of which is
considered to be equally plausible, and which is based on maximum
likelihood estimates.
\41\ See A Review of the Reference Dose and Reference
Concentration Processes, U.S. EPA, December 2002, and Methods for
Derivation of Inhalation Reference Concentrations and Application of
Inhalation Dosimetry, U.S. EPA, 1994.
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Many of the UFs used to account for variability and uncertainty in
the development of acute dose-response values are quite similar to
those developed for chronic durations. Additional adjustments are often
applied to account for uncertainty in extrapolation from observations
at one exposure duration (e.g., 4 hours) to derive an acute dose-
response value at another exposure duration (e.g., 1 hour). Not all
acute dose-response values are developed for the same purpose, and care
must be taken when interpreting the results of an acute assessment of
human health effects relative to the dose-response value or values
being exceeded. Where relevant to the estimated exposures, the lack of
acute dose-response values at different levels of severity should be
factored into the risk characterization as potential uncertainties.
Uncertainty also exists in the selection of ecological benchmarks
for the environmental risk screening assessment. We established a
hierarchy of preferred benchmark sources to allow selection of
benchmarks for each environmental HAP at each ecological assessment
endpoint. We searched for
[[Page 25104]]
benchmarks for three effect levels (i.e., no-effects level, threshold-
effect level, and probable effect level), but not all combinations of
ecological assessment/environmental HAP had benchmarks for all three
effect levels. Where multiple effect levels were available for a
particular HAP and assessment endpoint, we used all of the available
effect levels to help us determine whether risk exists and whether the
risk could be considered significant and widespread.
Although we make every effort to identify appropriate human health
effect dose-response values for all pollutants emitted by the sources
in this risk assessment, some HAP emitted by these source categories
are lacking dose-response assessments. Accordingly, these pollutants
cannot be included in the quantitative risk assessment, which could
result in quantitative estimates understating HAP risk. To help to
alleviate this potential underestimate, where we conclude similarity
with a HAP for which a dose-response value is available, we use that
value as a surrogate for the assessment of the HAP for which no value
is available. To the extent use of surrogates indicates appreciable
risk, we may identify a need to increase priority for an IRIS
assessment for that substance. We additionally note that, generally
speaking, HAP of greatest concern due to environmental exposures and
hazard are those for which dose-response assessments have been
performed, reducing the likelihood of understating risk. Further, HAP
not included in the quantitative assessment are assessed qualitatively
and considered in the risk characterization that informs the risk
management decisions, including consideration of HAP reductions
achieved by various control options.
For a group of compounds that are unspeciated (e.g., groups of
compounds that we do not know the exact composition of like glycol
ethers), we conservatively use the most protective dose-response value
of an individual compound in that group to estimate risk. Similarly,
for an individual compound in a group (e.g., ethylene glycol diethyl
ether) that does not have a specified dose-response value, we also
apply the most protective dose-response value from the other compounds
in the group to estimate risk.
e. Uncertainties in Acute Inhalation Screening Assessments
In addition to the uncertainties highlighted above, there are
several factors specific to the acute exposure assessment that the EPA
conducts as part of the risk review under section 112 of the CAA. The
accuracy of an acute inhalation exposure assessment depends on the
simultaneous occurrence of independent factors that may vary greatly,
such as hourly emissions rates, meteorology, and the presence of a
person. In the acute screening assessment that we conduct under the RTR
program, we assume that peak emissions from the source category and
reasonable worst-case air dispersion conditions (i.e., 99th percentile)
co-occur. We then include the additional assumption that a person is
located at this point at the same time. Together, these assumptions
represent a reasonable worst-case actual exposure scenario. In most
cases, it is unlikely that a person would be located at the point of
maximum exposure during the time when peak emissions and reasonable
worst-case air dispersion conditions occur simultaneously.
f. Uncertainties in the Multipathway and Environmental Risk Screening
Assessments
For each source category, we generally rely on site-specific levels
of PB-HAP or environmental HAP emissions to determine whether a refined
assessment of the impacts from multipathway exposures is necessary or
whether it is necessary to perform an environmental screening
assessment. This determination is based on the results of a three-
tiered screening assessment that relies on the outputs from models--
TRIM.FaTE and AERMOD--that estimate environmental pollutant
concentrations and human exposures for five PB-HAP (dioxins, POM,
mercury, cadmium, and arsenic) and two acid gases (HF and HCl). For
lead, we use AERMOD to determine ambient air concentrations, which are
then compared to the secondary NAAQS standard for lead. Two important
types of uncertainty associated with the use of these models in RTR
risk assessments and inherent to any assessment that relies on
environmental modeling are model uncertainty and input uncertainty.\42\
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\42\ In the context of this discussion, the term ``uncertainty''
as it pertains to exposure and risk encompasses both variability in
the range of expected inputs and screening results due to existing
spatial, temporal, and other factors, as well as uncertainty in
being able to accurately estimate the true result.
---------------------------------------------------------------------------
Model uncertainty concerns whether the model adequately represents
the actual processes (e.g., movement and accumulation) that might occur
in the environment. For example, does the model adequately describe the
movement of a pollutant through the soil? This type of uncertainty is
difficult to quantify. However, based on feedback received from
previous EPA SAB reviews and other reviews, we are confident that the
models used in the screening assessments are appropriate and state-of-
the-art for the multipathway and environmental screening risk
assessments conducted in support of RTRs.
Input uncertainty is concerned with how accurately the models have
been configured and parameterized for the assessment at hand. For Tier
1 of the multipathway and environmental screening assessments, we
configured the models to avoid underestimating exposure and risk. This
was accomplished by selecting upper-end values from nationally
representative datasets for the more influential parameters in the
environmental model, including selection and spatial configuration of
the area of interest, lake location and size, meteorology, surface
water, soil characteristics, and structure of the aquatic food web. We
also assume an ingestion exposure scenario and values for human
exposure factors that represent reasonable maximum exposures.
In Tier 2 of the multipathway and environmental screening
assessments, we refine the model inputs to account for meteorological
patterns in the vicinity of the facility versus using upper-end
national values, and we identify the actual location of lakes near the
facility rather than the default lake location that we apply in Tier 1.
By refining the screening approach in Tier 2 to account for local
geographical and meteorological data, we decrease the likelihood that
concentrations in environmental media are overestimated, thereby
increasing the usefulness of the screening assessment. In Tier 3 of the
screening assessments, we refine the model inputs again to account for
hour-by-hour plume-rise and the height of the mixing layer. We can also
use those hour-by-hour meteorological data in a TRIM.FaTE run using the
screening configuration corresponding to the lake location. These
refinements produce a more accurate estimate of chemical concentrations
in the media of interest, thereby reducing the uncertainty with those
estimates. The assumptions and the associated uncertainties regarding
the selected ingestion exposure scenario are the same for all three
tiers.
For the environmental screening assessment for acid gases, we
employ a single-tiered approach. We use the modeled air concentrations
and compare those with ecological benchmarks.
For all tiers of the multipathway and environmental screening
assessments,
[[Page 25105]]
our approach to addressing model input uncertainty is generally
cautious. We choose model inputs from the upper end of the range of
possible values for the influential parameters used in the models, and
we assume that the exposed individual exhibits ingestion behavior that
would lead to a high total exposure. This approach reduces the
likelihood of not identifying high risks for adverse impacts.
Despite the uncertainties, when individual pollutants or facilities
do not exceed screening threshold emission rates (i.e., screen out), we
are confident that the potential for adverse multipathway impacts on
human health is very low. On the other hand, when individual pollutants
or facilities do exceed screening threshold emission rates, it does not
mean that impacts are significant, only that we cannot rule out that
possibility and that a refined assessment for the site might be
necessary to obtain a more accurate risk characterization for the
source category.
The EPA evaluates the following HAP in the multipathway and/or
environmental risk screening assessments, where applicable: arsenic,
cadmium, dioxins/furans, lead, mercury (both inorganic and methyl
mercury), POM, HCl, and HF. These HAP represent pollutants that can
cause adverse impacts either through direct exposure to HAP in the air
or through exposure to HAP that are deposited from the air onto soils
and surface waters and then through the environment into the food web.
These HAP represent those HAP for which we can conduct a meaningful
multipathway or environmental screening risk assessment. For other HAP
not included in our screening assessments, the model has not been
parameterized such that it can be used for that purpose. In some cases,
depending on the HAP, we may not have appropriate multipathway models
that allow us to predict the concentration of that pollutant. The EPA
acknowledges that other HAP beyond these that we are evaluating may
have the potential to cause adverse effects and, therefore, the EPA may
evaluate other relevant HAP in the future, as modeling science and
resources allow.
G. How does the EPA perform the NESHAP technology review and NSPS
review?
1. NESHAP Technology Review
Our technology review primarily focuses on the identification and
evaluation of developments in practices, processes, and control
technologies that have occurred since the previous HON, P&R I, and P&R
II technology reviews were promulgated. Where we identify such
developments, we analyze their technical feasibility, estimated costs,
energy implications, and non-air environmental impacts. We also
consider the emission reductions associated with applying each
development. This analysis informs our decision of whether it is
``necessary'' to revise the CAA section 112 emissions standards. In
addition, we consider the appropriateness of applying controls to new
sources versus retrofitting existing sources. For this exercise, we
consider any of the following to be a ``development'':
Any add-on control technology or other equipment that was
not identified and considered during development of the original MACT
standards;
Any improvements in add-on control technology or other
equipment (that were identified and considered during development of
the original MACT standards) that could result in additional emissions
reduction;
Any work practice or operational procedure that was not
identified or considered during development of the original MACT
standards;
Any process change or pollution prevention alternative
that could be broadly applied to the industry and that was not
identified or considered during development of the original MACT
standards; and
Any significant changes in the cost (including cost
effectiveness) of applying controls (including controls the EPA
considered during the development of the original MACT standards).
In addition to reviewing the practices, processes, and control
technologies that were considered at the time we originally developed
the HON, P&R I, and P&R II, we review a variety of data sources in our
investigation of potential practices, processes, or controls to
consider. We also review the NESHAP and the available data to determine
if there are any unregulated emissions of HAP within the source
categories, and evaluate these data for use in developing new emission
standards. When reviewing MACT standards, we also address regulatory
gaps, such as missing standards for listed air toxics known to be
emitted from the source category. See sections II.C and II.D of this
preamble for information on the specific data sources that were
reviewed as part of the technology review.
2. NSPS Review
As noted in the section II.A.2 of this preamble, CAA section 111
requires the EPA, at least every 8 years to review and, if appropriate
revise the standards of performance applicable to new, modified, and
reconstructed sources. If the EPA determines that it is appropriate to
review the standards of performance, the revised standards must reflect
the degree of emission limitation achievable through the application of
the BSER considering the cost of achieving such reduction and any non-
air quality health and environmental impact and energy requirements.
CAA section 111(a)(1).
In reviewing an NSPS to determine whether it is ``appropriate'' to
revise the standards of performance, the EPA evaluates the statutory
factors, which may include consideration of the following information:
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.
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.
In evaluating whether the cost of a particular system of emission
reduction is reasonable, the EPA considers various costs associated
with the particular air pollution control measure or a level of
control, including capital costs and operating costs, and the emission
reductions that the control measure or particular level of control can
achieve. The Agency considers these costs in the context of the
industry's overall capital expenditures and revenues. The Agency also
considers cost-effectiveness analysis as a useful metric and a means of
evaluating whether a given control achieves emission reduction at a
reasonable cost. A cost-effectiveness analysis allows comparisons of
relative costs and outcomes (effects) of two or more options. In
general, cost-effectiveness is a measure of the
[[Page 25106]]
outcomes produced by resources spent. In the context of air pollution
control options, cost effectiveness typically refers to the annualized
cost of implementing an air pollution control option divided by the
amount of pollutant reductions realized annually.
After the EPA evaluates the statutory factors, the EPA compares the
various systems of emission reductions and determines which system is
``best,'' and therefore represents the BSER. The EPA then establishes a
standard of performance that reflects the degree of emission limitation
achievable through the implementation of the BSER. In doing this
analysis, the EPA can determine whether subcategorization is
appropriate based on classes, types, and sizes of sources, and may
identify a different BSER and establish different performance standards
for each subcategory. The result of the analysis and BSER determination
leads to standards of performance that apply to facilities that begin
construction, reconstruction, or modification after the date of
publication of the proposed standards in the Federal Register. Because
the NSPS reflect the BSER under conditions of proper operation and
maintenance, in doing its review, the EPA also evaluates and determines
the proper testing, monitoring, recordkeeping and reporting
requirements needed to ensure compliance with the emission standards.
See section II.C of this preamble for information on the specific
data sources that were reviewed as part of this action.
III. Proposed Rule Summary and Rationale
A. What are the results of the risk assessment and analyses?
As previously discussed, we conducted risk assessments for the
SOCMI and Neoprene Production (within P&R I) source categories. We
previously identified EtO as a cancer risk driver from facilities with
HON-subject processes in the first risk assessment we conducted in
2006. However, the EPA's IRIS inhalation URE for EtO was revised in
2016,\43\ based on new data, showing EtO to be more carcinogenic than
previously understood (i.e., resulting in a URE 60 times greater than
the previous URE over a 70-year lifetime). Additionally, the EPA's IRIS
inhalation URE for chloroprene was finalized in 2010 (there was no
previous URE).\44\ Chloroprene is emitted from some HON-subject
processes (e.g., chloroprene production, other chlorinated SOCMI
chemical production processes), but is mostly emitted from neoprene
production processes subject to P&R I. We briefly present results of
the risk assessments below and in more detail in the documents titled
Residual Risk Assessment for the SOCMI Source Category in Support of
the 2023 Risk and Technology Review Proposed Rule and Residual Risk
Assessment for the Polymers & Resins I Neoprene Production Source
Category in Support of the 2023 Risk and Technology Review Proposed
Rule, which are available in the docket for this rulemaking.
---------------------------------------------------------------------------
\43\ 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.
\44\ 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.
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1. Chronic Inhalation Risk Assessment Results
a. SOCMI Source Category
The results of the chronic baseline inhalation cancer risk
assessment, which are estimated using modeling and is the case for all
risk results presented here and in subsequent sections, indicate that,
based on estimates of current actual and allowable emissions, the MIR
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 based on actual and allowable emission
levels is 2 excess cancer cases per year. EtO emissions contribute 89
percent of the total cancer incidence. 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 87,000 people, and the population exposed to cancer risk
greater than or equal to 1-in-1 million is approximately 7.2 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. See Table 1 of this preamble for a summary of the
HON inhalation risk assessment results.
Table 1--SOCMI Source Category Inhalation Risk Assessment Results Based on Actual and Allowable Emissions \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Estimated population at increased
Number of individual risk of cancer Estimated annual Refined maximum
Risk assessment facilities cancer risk (- -------------------------------------- cancer incidence Maximum chronic screening acute
\2\ in-1 million) (cases per year) noncancer TOSHI noncancer HQ
\3\ >100-in-1 million >=1-in-1 million
--------------------------------------------------------------------------------------------------------------------------------------------------------
SOCMI Source Category......... 195 2,000 87,000 (50 km)... 7.2 million (50 2 2 (maleic HQREL = 3
km). anhydride). (chlorine).
2 (chlorine).... HQREL = 3
(acrolein).
Facility-wide \4\............. 195 2,000 95,000 (50 km)... 8.9 million (50 2 4 (chlorine,
km). acrylic acid,
and
acrylonitrile).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Actual emissions equal allowable emissions; therefore, actual risks equal allowable risks.
\2\ There are 207 HON facilities; however, only 195 of these facilities are included in the risk assessment based on available data, which corresponds
to 222 Emission Information System (EIS) facility IDs.
\3\ Maximum individual excess lifetime cancer risk due to HAP emissions.
\4\ See ``Facility-Wide Risk Results'' in section III.A.5 of this preamble for more details on this risk assessment.
[[Page 25107]]
b. Neoprene Production Source Category
The results of the chronic baseline inhalation cancer risk
assessment indicate that, based on estimates of current actual and
allowable emissions, the MIR posed by the Neoprene Production source
category within P&R I is 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).\45\
The total estimated cancer incidence based on actual and allowable
emission levels is 0.05 excess cancer cases per year, or 1 cancer case
every 20 years. Within 50 km (~31 miles) of the one facility in this
source category, the population exposed to cancer risks greater than
100-in-1 million for actual and allowable emissions is approximately
2,100 people, and the population exposed to cancer risks greater than
or equal to 1-in-1 million is approximately 690,000 people. In
addition, the maximum modeled chronic noncancer TOSHI for the source
category based on actual and allowable emissions is estimated to be
0.05 (for respiratory effects) from chloroprene emissions. See Table 2
of this preamble for a summary of the neoprene production inhalation
risk assessment results.
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\45\ We note that chloroprene (and all other HAP) emissions from
HON processes co-located at the neoprene production facility result
in an MIR of 90-in-1 million.
Table 2--Neoprene Production Source Category Inhalation Risk Assessment Results Based on Actual and Allowable Emissions \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Estimated population at increased
Number of individual risk of cancer Estimated annual Maximum
Risk assessment facilities cancer risk (- -------------------------------------- cancer incidence Maximum chronic screening acute
\2\ in-1 million) (cases per year) noncancer TOSHI noncancer HQ
\3\ >100-in-1 million >=1-in-1 million
--------------------------------------------------------------------------------------------------------------------------------------------------------
Neoprene Production Source 1 500 2,100 (50 km).... 690,000 (50 km).. 0.05 0.05 HQREL = 0.3
Category. (chloroprene). (chloroform).
Facility-wide \4\............. 1 600 2,300 (50 km).... 890,000 (50 km).. 0.06 0.3 (chlorine)..
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Actual emissions equal allowable emissions; therefore, actual risks equal allowable risks.
\2\ Number of facilities evaluated in the risk analysis.
\3\ Maximum individual excess lifetime cancer risk due to HAP emissions.
\4\ See ``Facility-Wide Risk Results'' in section III.A.5 of this preamble for more details on this risk assessment.
2. Screening Level Acute Risk Assessment Results
a. SOCMI Source Category
As presented in Table 1 of this preamble, the estimated worst-case
off-site acute exposures to emissions from the SOCMI source category
result in a maximum modeled acute noncancer HQ of 3 based on the RELs
for chlorine and acrolein. HON process emissions from two other
facilities result in acute noncancer HQs of 2 based on the RELs for
formaldehyde and chloroform. Detailed information about the assessment,
including evaluation of the screening-level acute risk assessment
results, is provided in the main body and Appendix 10 of the document
titled Residual Risk Assessment for the SOCMI Source Category in
Support of the 2023 Risk and Technology Review Proposed Rule, which is
available in the docket for this rulemaking.
b. Neoprene Production Source Category
As presented in Table 2 of this preamble, the estimated worst-case
acute exposures to emissions from the Neoprene Production source
category result in a maximum modeled acute noncancer HQ of 0.3 based on
the REL for chloroform. Detailed information about the assessment is
provided in the document titled Residual Risk Assessment for the
Polymers & Resins I Neoprene Production Source Category in Support of
the 2023 Risk and Technology Review Proposed Rule, which is available
in the docket for this rulemaking.
3. Multipathway Risk Screening Results
a. SOCMI Source Category
For the SOCMI source category, 71 facilities emitted at least 1 PB-
HAP, including arsenic, cadmium, dioxins, mercury, and POMs.\46\
Emissions of these PB-HAP from each facility were compared to the
respective pollutant-specific Tier 1 screening emission thresholds. The
Tier 1 screening analysis indicated 9 facilities exceeded the Tier 1
emission threshold for arsenic, 3 facilities for cadmium, 9 facilities
for dioxins, 9 facilities for mercury, and 20 facilities for POM.
---------------------------------------------------------------------------
\46\ Note that while the multipathway risk screening results
includes metals (e.g., arsenic, cadmium, mercury, arsenic) and POMs,
the EPA in most instances used a conservative approach and modeled
whole facility emissions inventories for the SOCMI source category.
This means that emissions from other source categories were included
for this analysis, and we have no information suggesting that metals
or POMs are emitted from HON processes. See Appendix 1 of the
document titled Residual Risk Assessment for the SOCMI Source
Category in Support of the 2023 Risk and Technology Review Proposed
Rule, which is available in the docket for this rulemaking for more
details about development of the risk modeling file.
---------------------------------------------------------------------------
For facilities that exceeded the Tier 1 multipathway screening
threshold emission rate for one or more PB-HAP, we used additional
facility site-specific information to perform a Tier 2 multipathway
risk screening assessment. The Tier 2 assessment resulted in a maximum
Tier 2 noncancer screening value of 60 from methyl mercury and 2 for
cadmium based on the fisher scenario and a cancer screening value of
100 from POM for the gardener scenario. The Tier 2 assessment indicated
the maximum arsenic and dioxin cancer screening values were 30 and 2,
respectively, for the gardener scenario, and therefore no further
screening was performed.
For mercury and cadmium, a Tier 3 screening assessment was
conducted for the fisher scenario while a Tier 3 screening assessment
was conducted for POM for the gardener scenario. In the Tier 3
screening for the fisher scenario, lakes near the facilities were
reviewed on aerial photographs to ensure they were accessible for
fishing. Any lakes not accessible were removed from the assessment.
After conducting the Tier 3 assessment, the screening values for
mercury and cadmium remained at 60 and 2, respectively.
The Tier 3 gardener scenario was refined by identifying the
location of the residence most impacted by POM emissions from the
facility as opposed to the worst-case near-field location used in the
Tier 2 assessment. Based on these Tier 3 refinements to the gardener
scenario, the maximum Tier 3 cancer screening value for POM was 20.
An exceedance of a screening threshold emission rate in any of the
tiers cannot be equated with a risk value or an HQ (or HI). Rather, it
represents
[[Page 25108]]
a high-end estimate of what the risk or hazard may be. For example, a
screening value of 2 for a non-carcinogen can be interpreted to mean
that the Agency is confident that the HQ would be lower than 2.
Similarly, a Tier 2 cancer screening value of 7 means that we are
confident that the cancer risk is lower than 7-in-1 million. Our
confidence comes from the conservative, or health-protective,
assumptions encompassed in the screening tiers: the Agency chooses
inputs from the upper end of the range of possible values for the
influential parameters used in the screening tiers, and the Agency
assumes that the exposed individual exhibits ingestion behavior that
would lead to a high total exposure.
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 2 screening results to site-
specific risk estimates for five previously assessed source categories.
These are the five source categories, assessed over the past 4 years,
which had characteristics that make them most useful for interpreting
the HON screening results. For these source categories, the EPA
assessed fisher and/or gardener risks for arsenic, cadmium, and/or
mercury by conducting site-specific assessments. The EPA used AERMOD
for modeling air dispersion and Tier 2 screens that used multi-facility
aggregation of chemical loading to lakes where appropriate. These
assessments indicated that cancer and noncancer site-specific risk
values were at least 50 times lower than the respective Tier 2
screening values for the assessed facilities, with the exception of
noncancer risks for cadmium for the gardener scenario, where the
reduction was at least 10 times (refer to EPA Docket ID: EPA-HQ-OAR-
2017-0015 and EPA-HQ-OAR-2019-0373 for a copy of these reports).\47\
---------------------------------------------------------------------------
\47\ EPA Docket records (EPA-HQ-OAR-2017-0015): Appendix 11 of
the Residual Risk Assessment for the Taconite Manufacturing Source
Category in Support of the Risk and Technology Review 2019 Proposed
Rule; Appendix 11 of the Residual Risk Assessment for the Integrated
Iron and Steel Source Category in Support of the Risk and Technology
Review 2019 Proposed Rule; Appendix 11 of the Residual Risk
Assessment for the Portland Cement Manufacturing Source Category in
Support of the 2018 Risk and Technology Review Final Rule; Appendix
11 of the Residual Risk Assessment for the Coal and Oil-Fired EGU
Source Category in Support of the 2018 Risk and Technology Review
Proposed Rule; and EPA Docket: (EPA-HQ-OAR-2019-0373): Appendix 11
of the Residual Risk Assessment for Iron and Steel Foundries Source
Category in Support of the 2019 Risk and Technology Review Proposed
Rule.
---------------------------------------------------------------------------
Based on our review of these analyses, if the Agency was to perform
a site-specific assessment for the SOCMI Source Category, the Agency
would expect similar magnitudes of decreases from the Tier 2 SVs. As
such, given the conservative nature of the screens and the level of
additional refinements that would go into a site-specific multipathway
assessment, were one to be conducted, we are confident that the HQ for
ingestion exposure, specifically cadmium and mercury through fish
ingestion, is at or below 1. For POM, the maximum cancer risk under the
rural gardener scenario would likely decrease to below 1-in-1 million.
Further details on the Tier 3 screening assessment can be found in
Appendix 10-11 of Residual Risk Assessment for the SOCMI Source
Category in Support of the 2023 Risk and Technology Review Proposed
Rule.
In evaluating the potential for multipathway risk from emissions of
lead, we compared modeled annual lead concentrations to the primary
NAAQS for lead (0.15 [micro]g/m\3\). The highest annual lead
concentration of 0.004 [micro]g/m\3\ is well below the NAAQS for lead,
indicating low potential for multipathway risk of concern due to lead
emissions.
Detailed information about the assessment is provided in the
document titled Residual Risk Assessment for the SOCMI Source Category
in Support of the 2023 Risk and Technology Review Proposed Rule, which
is available in the docket for this rulemaking.
b. Neoprene Production Source Category
As mentioned above, we did not identify reported PB-HAP emissions
from the Neoprene Production source category, and we could not
undertake the three-tier human health risk screening assessment that
was conducted for the SOCMI source category. However, we note that we
would expect dioxins likely to be formed by combustion controls used to
control chlorinated chemicals such as chloroprene from this source
category. As no facility exceeded a Tier 2 screening value for dioxins
in the HON multipathway risk screening assessment, including 4 HON
facilities with dioxin emission rates higher than the standard being
proposed for dioxins for the Neoprene Production source category (and 1
HON facility with a dioxins emission rate approximately 20 times higher
than the proposed Neoprene Production emission limit), we would expect
multipathway risk from dioxins from the Neoprene Production source
category to screen lower than they are for the SOCMI source category
after compliance with the proposed dioxin limit occurs.
4. Environmental Risk Screening Results
a. SOCMI Source Category
As described in section III.A of this preamble, we conducted a
screening assessment for adverse environmental effects for the SOCMI
source category. The environmental screening assessment included the
following HAP: arsenic, cadmium, dioxin, methyl mercury, divalent
mercury, and POMs.\48\
---------------------------------------------------------------------------
\48\ Note that while the environmental risk screening results
includes metals (e.g., arsenic, cadmium, mercury, arsenic) and POMs,
the EPA in most instances used a conservative approach and modeled
whole facility emissions inventories for the SOCMI source category.
This means that emissions from other source categories were included
for this analysis, and we have no information suggesting that metals
or POMs are emitted from HON processes. See Appendix 1 of the
document titled Residual Risk Assessment for the SOCMI Source
Category in Support of the 2023 Risk and Technology Review Proposed
Rule, which is available in the docket for this rulemaking for more
details about development of the risk modeling file.
---------------------------------------------------------------------------
In the Tier 1 screening analysis for PB-HAP (other than lead, which
was evaluated differently), arsenic emissions had no exceedances for
any ecological benchmark. The maximum Tier 1 screening value was 200
for methyl mercury emissions for the surface soil No Observed Adverse
Effects Level (NOAEL) avian ground insectivores benchmark. The other
pollutants (cadmium, dioxins, POMs, divalent mercury, methyl mercury)
had Tier 1 screening values above various benchmarks. Therefore, a Tier
2 screening assessment was performed for cadmium, dioxins, POMs,
divalent mercury, and methyl mercury emissions.
In the Tier 2 screen, cadmium, dioxins, and POM emissions did not
exceed any ecological benchmark. The following Tier 2 screening values
were exceeded for methyl mercury emissions: a screening value of 5 for
the fish-eating birds NOAEL benchmark (specifically for the small duck
called the merganser), a screening value of 2 for the maximum allowable
toxicant level for the merganser, and a screening value of 3 for avian
ground insectivores (woodcock). The following Tier 2 screening values
were exceeded for divalent mercury emissions: a screening value of 4
for a sediment threshold level and a screening value of 2 for an
invertebrate threshold level. All of the Tier 2 exceedances for the
merganser and sediment benchmarks are the result of emissions from 3
facilities acting on the same lake. The invertebrate and
[[Page 25109]]
insectivore soil benchmarks are the result of emissions from 1
facility.
Since there were Tier 2 exceedances, we conducted a Tier 3
environmental risk screen. In the Tier 3 environmental risk screen, we
looked at aerial photos of the lake being impacted by mercury emissions
from the three HON-subject facilities. The aerial photos show that the
``lake'' is located in an industrialized area, has been channelized,
and largely filled/drained. Therefore, it was determined that this
``lake'' would not support a fish population. We also looked at aerial
photos of the facility that was driving the invertebrate and
insectivore Tier 2 soil exceedances due to mercury emissions. The
aerial photos show that the facility is located in a heavily
industrialized area with the nearest ``natural areas'' being located
more than 1500 meters from the facility. We re-calculated the soil
screening values with the industrial areas removed and calculated a
maximum Tier 3 soil screen value for mercury of 1.
We did not estimate any exceedances of the secondary lead NAAQS.
The highest annual lead concentration of 0.004 [micro]g/m\3\ is well
below the NAAQS for lead, indicating low potential for environmental
risk of concern due to lead emissions.
We also conducted an environmental risk screening assessment
specifically for acid gases (i.e., HCl and HF) for the SOCMI source
category. For HCl and HF, the average modeled concentration around each
facility (i.e., the average concentration of all off-site data points
in the modeling domain) did not exceed any ecological benchmark. In
addition, each individual modeled concentration of HCl and HF (i.e.,
each off-site data point in the modeling domain) was below the
ecological benchmarks for all facilities.
Based on the results of the environmental risk screening analysis,
we do not expect an adverse environmental effect as a result of HAP
emissions from this source category. Detailed information about the
assessment is provided in the document titled Residual Risk Assessment
for the SOCMI Source Category in Support of the 2023 Risk and
Technology Review Proposed Rule, which is available in the docket for
this rulemaking.
b. Neoprene Production Source Category
As mentioned above, 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 note that no facility exceeded a Tier 2 screening value for
dioxins in the HON environmental risk screening assessment, including 4
HON facilities with dioxin emission rates higher than those being
proposed for the Neoprene Production source category and 1 HON facility
with a dioxin emission rate approximately 20 times higher than the
proposed emission limits for the Neoprene Production source category.
Furthermore, we conducted an environmental risk screening
assessment for acid gases (i.e., HCl and HF) for the Neoprene
Production source category; however, there were no reported emissions
of HF at this facility. For HCl, the average modeled concentration
around the facility (i.e., the average concentration of all off-site
data points in the modeling domain) did not exceed any ecological
benchmark. In addition, each individual modeled concentration of HCl
(i.e., each off-site data point in the modeling domain) was below the
ecological benchmarks for the facility. Detailed information about the
assessment is provided in the document titled Residual Risk Assessment
for the Polymers & Resins I Neoprene Production Source Category in
Support of the 2023 Risk and Technology Review Proposed Rule, which is
available in the docket for this rulemaking.
5. Facility-Wide Risk Results
a. HON Facilities
We conducted an assessment of facility-wide (or ``whole facility'')
risk as described above to characterize the source category risk in the
context of whole facility risk. We estimated whole facility risks using
the NEI-based data described in section III.C of this preamble. The
maximum lifetime individual cancer risk posed by the 195 modeled
facilities (there are 207 HON facilities; however, only 195 of these
facilities are included in the risk assessment based on available data,
which corresponds to 222 EIS facility IDs) 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. EtO
emissions contribute 81 percent and chloroprene emissions contribute 3
percent of the total cancer incidence. 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
95,000 people, and the population exposed to cancer risk greater than
or equal to 1-in-1 million is approximately 8.9 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.
b. Neoprene Production Facility
We also performed a facility-wide assessment for the facility in
the Neoprene Production source category to characterize the source
category risk in the context of whole facility risk. Note that this
facility was also included the HON facility-wide risk assessment
because it has HON sources as well as neoprene production sources (see
section III.A.5.a of this preamble). The maximum lifetime individual
cancer risk posed by the one neoprene production facility based on
whole facility emissions is 600-in-1 million driven by 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). The total estimated cancer incidence
based on facility-wide emission levels is 0.06 excess cancer cases per
year, or 1 case approximately every 17 years. Within 50 km (~31 miles)
of the Neoprene Production facility, the population exposed to cancer
risk greater than 100-in-1 million for facility-wide emissions is
approximately 2,300 people, and the population exposed to cancer risk
greater than or equal to 1-in-1 million is approximately 890,000
people. The maximum chronic noncancer TOSHI posed by whole facility
emissions is estimated to be 0.3 (for respiratory effects) due to
chlorine emissions.
6. Community-Based Risk Assessment
We also conducted a community-based risk assessment for HON-subject
[[Page 25110]]
facilities (which includes the one neoprene production facility). The
goal of this assessment is to estimate cancer risk from HAP emitted
from all local stationary point sources for which we have emissions
data. We estimated the overall inhalation cancer risk due to emissions
from all stationary point sources impacting census blocks within 10 km
(~6.2 miles) of the 195 HON facilities. Specifically, we combined the
modeled impacts from category and non-category HAP sources at HON
facilities, as well as other stationary point source HAP emissions.
Within 10 km of HON-subject facilities, we identified 2,700 non-source
category facilities that could potentially also contribute to HAP
inhalation exposures.
We first looked at what the maximum risk is for communities around
SOCMI facilities. The results indicate that the community-level maximum
individual cancer risk is the same as in the source category MIR and
maximum risk for the facility-wide assessment, 2,000-in-1 million. The
assessment estimated that essentially all (greater than 99.9 percent)
of the MIR is attributable to emissions from the SOCMI source category.
We then looked at what the communities' risks are from all emissions
sources for which we had data. Within 10 km, the population exposed to
cancer risks greater than 100-in-1 million from all nearby emissions is
approximately 104,000. For comparison, approximately 87,000 people have
cancer risks greater than 100-in-1 million due to HON emissions and
approximately 95,000 people have cancer risks greater than 100-in-1
million due to HON facility-wide emissions (see Table 3 of this
preamble). The overall cancer incidence for this exposed population
(i.e., populations with risks greater than 100-in-1 million living
within 10 km of HON facilities) is 0.5, with 91 percent of the cancer
incidence from HON processes, 7 percent from non-HON processes at HON
facilities (a total of 98 percent from HON facilities), and 2 percent
from other nearby stationary point sources that are not HON facilities.
The population exposed to cancer risks greater than or equal to 1-
in-1 million in the community-based assessment is approximately 5.8
million people. For comparison, approximately 2.8 million people have
cancer risks greater than or equal to 1-in-1 million due to HON process
emissions and approximately 3.2 million people have cancer risks
greater than 1-in-1 million due to HON facility-wide emissions (see
Table 3 of this preamble). The overall cancer incidence for this
exposed population (i.e., people with risks greater than or equal to 1-
in-1 million and living within 10 km of HON facilities) is 2, with 69
percent of the incidence due to emissions from HON processes, 16
percent from emissions of non-HON processes at HON facilities (that is,
a total of 85 percent from emissions from HON facilities) and 15
percent from emissions from other nearby stationary sources that are
not HON facilities.
After the controls proposed in this action are implemented for both
the SOCMI and Neoprene Production source categories (see section
III.B.2), the community-level maximum individual cancer risk will be
reduced to the same as the facility-wide assessment, 1,000-in-1
million, from non-HON processes emitting ethylene oxide at a single
facility. The assessment estimated that 98 percent of the MIR is
attributable to emissions from non-HON processes at a HON facility. The
population (within 10 km of HON facilities) exposed to cancer risks
greater than 100-in-1 million from all nearby emissions will be
significantly reduced from 104,000 people to 4,200 people; a 96 percent
reduction from the baseline. The populations exposed to cancer risks
greater than 100-in-1 million from the SOCMI source category and
facility-wide emissions are similarly reduced, from 87,000 people to 0
for source category emissions and from 95,000 to 2,500 for facility-
wide emissions (see Table 3 of this preamble). Furthermore, the overall
cancer incidence for this exposed population is expected to be reduced
from 0.5 to 0.02. The percentage of the cancer incidence due to
emissions of HON processes is reduced from 91 percent to 9 percent. The
percentage of the cancer incidence due to emissions of non-HON
processes at HON facilities and emissions from other nearby stationary
sources proportionately shifts to 57 percent and 34 percent
respectively. EtO emissions across these sources remain the largest
source of incidence, accounting for 89 percent of the overall cancer
incidence for this exposed population.
The post-control population exposed to cancer risks greater than or
equal to 1-in-1 million, 5.8 million people, would remain approximately
the same as the baseline. In comparison, after the controls proposed in
this action, the number of people with risks greater than or equal to
1-in-1 million due to source category emissions would reduce from 2.8
million to 2.5 million and due to facility-wide emissions from 3.2
million to 3.1 million (see Table 3 of this preamble). The lack of
change from the baseline is largely due to the impacts from non-HON
processes at HON facilities and from other nearby stationary sources
maintaining the risks greater than or equal to 1-in-1 million for the
exposed population. However, the overall cancer incidence for this
exposed population is expected to be reduced from 2 to 0.7. The
percentage of the cancer incidence from HON processes is expected to
decrease from 69 to 38 percent. The cancer incidence from non-HON
processes at HON facilities and from other nearby stationary sources
are expected to proportionately shift to 29 percent and 32 percent,
respectively.
Overall, the proposed emission reductions in this rule provide a
substantial reduction in risks to the communities living around HON
facilities. The number of people at cancer risks greater than 100-in-1
million is reduced from 104,000 people to 4,200 people, a 96 percent
reduction. EtO emissions are by far the largest source of remaining
risk in the community-based risk assessment, accounting for 85 percent
across all sources. Moving forward, the EPA expects to continue to
address EtO emissions for other chemical sector source categories.
Table 3--Inhalation Cancer Risk Assessment Results for Communities Living Within 10 km of HON Facilities
----------------------------------------------------------------------------------------------------------------
Maximum Estimated population at increased risk of cancer
individual ------------------------------------------------------
Risk assessment cancer risk (-in-
1 million) >100-in-1 million >=1-in-1 million
----------------------------------------------------------------------------------------------------------------
Baseline (Pre-Control)
----------------------------------------------------------------------------------------------------------------
SOCMI Source Category.................. 2,000 87,000 (10 km)............ 2.8 million (10 km).
Facility-wide.......................... 2,000 95,000 (10 km)............ 3.2 million (10 km).
Community.............................. 2,000 104,000 (10 km)........... 5.8 million (10 km).
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[[Page 25111]]
After Implementation of Proposed Controls (Post-Control)
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SOCMI Source Category.................. 100 0 (10 km)................. 2.5 million (10 km).
Facility-wide \1\...................... 1,000 2,500 (10 km)............. 3.1 million (10 km).
Community.............................. 1,000 4,200 (10 km)............. 5.8 million (10 km).
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\1\ Facility-wide post-control risks include proposed controls for the SOCMI and Neoprene Production source
categories.
B. What are our proposed decisions regarding risk acceptability, ample
margin of safety, and adverse environmental effect?
1. Risk Acceptability Under the Current MACT Standards
As noted in section II.D of this preamble, we weigh a wide range of
health risk measures and factors in our risk acceptability
determination, including the cancer MIR, the number of persons in
various cancer and noncancer risk ranges, cancer incidence, the maximum
noncancer TOSHI, the maximum acute noncancer HQ, the extent of
noncancer risks, the distribution of cancer and noncancer risks in the
exposed population, and risk estimation uncertainties (54 FR 38044,
September 14, 1989).
Under the current MACT standards for the SOCMI source category, the
risk results indicate that the MIR is 2,000-in-1 million, driven by
emissions of EtO, and well above 100-in-1 million, which is the
presumptive limit of acceptability. The estimated incidence of cancer
due to inhalation exposures is 2 excess cancer case per year. The
population estimated to be exposed to cancer risks greater than 100-in-
1 million is approximately 87,000, and the population estimated to be
exposed to cancer risks greater than or equal to 1-in-1 million is
approximately 7.2 million. The estimated maximum chronic noncancer
TOSHI from inhalation exposure for this source category is 2 for
neurological effects. The acute risk screening assessment of reasonable
worst-case inhalation impacts indicates a maximum acute HQ of 3.
Under the current MACT standards for the Neoprene Production source
category, the risk results indicate that the MIR is 500-in-1 million,
driven by emissions of chloroprene, and is above 100-in-1 million, the
presumptive limit of acceptability. The estimated incidence of cancer
due to inhalation exposures is 0.05 excess cancer case per year. The
population estimated to be exposed to cancer risks greater than 100-in-
1 million is approximately 2,100, and the population estimated to be
exposed to cancer risks greater than or equal to 1-in-1 million is
approximately 690,000 million. The estimated maximum chronic noncancer
TOSHI from inhalation exposure for this source category is 0.05 for
neurological effects, indicating low likelihood of adverse noncancer
effects from long-term inhalation exposures. The acute risk screening
assessment of reasonable worst-case inhalation impacts indicates a
maximum acute HQ of 0.3. Therefore, we conclude that adverse effects
from acute exposure to emissions from this category are not
anticipated.
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. As noted in section II.A
of this preamble, when 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. Therefore, pursuant to CAA section 112(f)(2), we are proposing
certain standards for emission sources of EtO in the HON and certain
standards for emission sources of chloroprene from the Neoprene
Production source category that are more protective than the current
HON and P&R I MACT standards.
2. Proposed Controls To Address Unacceptable Risks
As previously discussed, we conducted risk assessments of the SOCMI
and Neoprene Production source categories because the 2016 revisions to
the EPA's IRIS inhalation URE for EtO and the 2010 development of the
EPA's IRIS inhalation URE for chloroprene showed that both these
pollutants are more toxic than previously known.
For the SOCMI source category, we identified EtO as the cancer risk
driver from HON sources. 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.
From our residual risk assessment, eight facilities with emissions of
EtO from various HON processes have cancer risks above 100-in-1
million, and many different emission sources drive risk at these
facilities. Thus, in order to reduce emissions of EtO from HON
processes, the EPA is proposing more stringent control requirements for
process vents, storage vessels, equipment leaks, heat exchange systems,
wastewater, maintenance vents, flares, and PRDs that emit or have the
potential to emit EtO. As discussed later in this preamble, we are
proposing that these requirements that will reduce risk to an
acceptable level also provide an ample margin of safety to protect
public health, and that no additional requirements are needed to
prevent an adverse environmental effect.
For the Neoprene Production source category, we identified
chloroprene as the HAP cancer risk driver from the only facility in the
Neoprene Production source category. Thus, in order to reduce risk
posed by emissions from
[[Page 25112]]
neoprene production processes to an acceptable level, the EPA is
proposing more stringent control requirements for process vents,
storage vessels, wastewater, maintenance vents, and PRDs that emit or
have the potential to emit chloroprene. Also, as discussed later in
this preamble, we are proposing that these requirements that will
reduce risk to an acceptable level also provide an ample margin of
safety to protect public health, and that no additional requirements
are needed to prevent an adverse environmental effect.
We discuss the control options we evaluated for reducing EtO
emissions from HON processes in section III.B.2.a of this preamble and
discuss the control options we evaluated for reducing chloroprene
emissions from P&R I processes producing neoprene in section III.B.2.b
of this preamble.
a. EtO Controls for HON Processes
i. Process Vents and Storage Vessels
Emissions of EtO can occur from several types of gas streams
associated with HON processes, such as distillation columns, evaporator
vents, and vacuum operations, as well as during vapor displacements and
heating losses. HON storage vessels are used to store liquid and
gaseous feedstocks for use in a process, as well as to store liquid and
gaseous products from a process. EtO is typically stored under pressure
as a liquified gas, but may also be found in small amounts in
atmospheric storage vessels storing liquid products that are formed
with ethylene oxide as a reactant in their production. Typical
emissions from atmospheric storage tanks occur from working and
breathing losses while pressure vessels are considered closed systems
and, if properly maintained and operated, should have virtually no
emissions. In some instances, pressurized vessels also could use a
blanket of inert gas, most often nitrogen, to maintain a non-
decomposable vapor space, and continuous purge of vapor space from non-
loading operations could also lead to emissions from storage vessels.
The current HON standards divide process vents into Group 1 process
vents, which require control, and Group 2 process vents, which
generally do not require controls provided they do not exceed Group 1
thresholds. All HON Group 1 and Group 2 process vents are continuous.
The Group 1 and Group 2 designations for process vents are based on
volumetric flow rate, total organic HAP concentration, and the TRE
index value.\49\ The current HON standard requires uncontrolled Group 1
process vents to reduce total organic HAP emissions by 98 percent by
weight by venting emissions through a closed vent system to any
combination of control devices or to vent emissions through a closed
vent system to a flare. We provide more details about process vents in
our technology review discussion (see section III.C.3 of this
preamble).
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\49\ See section III.C.3.a of this preamble for a description of
the TRE index value and how the concept is currently used in the
HON.
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Similarly, the current HON standards divide storage vessels into
Group 1 storage vessels, which require control, and Group 2 storage
vessels, which generally do not require controls provided they do not
exceed Group 1 thresholds. The Group 1 and Group 2 designation for
storage vessels is based on the volume of the storage vessel and MTVP
of the material stored. Group 1 storage vessels are those with
capacities between 75 m\3\ and 151 m\3\ and a MTVP greater than or
equal to 13.1 kPa, and those with capacities greater than or equal to
151 m\3\ and a MTVP greater than or equal to 5.2 kPa. The current HON
standards require Group 1 storage vessels to reduce total HAP emissions
by 95 percent (or 90 percent if the storage vessel was installed on or
before December 31, 1992) by venting emissions through a closed vent
system to any combination of control devices or to vent emissions
through a closed vent system to a flare. Owners and operators of Group
1 storage vessels storing a liquid with a MTVP of total organic HAP
less than 76.6 kPa are also allowed to reduce organic HAP by utilizing
an IFR, an EFR, an EFR converted to an IFR, routing the emissions to a
process or a fuel gas system, or vapor balancing. For Group 1 storage
vessels storing a liquid with a MTVP of total organic HAP greater than
or equal to 76.6 kPa, owners and operators can reduce organic HAP
emissions by 95 percent by venting emissions through a closed vent
system to any combination of control devices, control emissions by
routing them to a process or a fuel gas system, or by using vapor
balancing. Pressure vessels (operating in excess of 204.9 kPa without
emissions to the atmosphere) may also store materials with EtO. For
storage vessels, the HON allows use of a design evaluation instead of a
performance test to determine the percent reduction of control devices
for any quantity of total uncontrolled organic HAP emissions being sent
to the control device. We provide more details about storage vessels in
our technology review discussion (see section III.C.2 of this preamble)
Results of our risk assessment indicate that two HON facilities
present cancer risks greater than 100-in-1 million just from EtO
emissions from process vent sources. At one of the two facilities, EtO
risk from process vent emission sources emitted through PRDs is
approximately 75 percent of the facility's total SOCMI source category
risk of 2000-in-1 million. At the other facility, EtO risk from process
vent emission sources is approximately 20 percent of the facility's
total SOCMI source category risk of 500-in-1 million. Additionally, EtO
from storage vessels accounts for approximately 70-in-1 million of the
source category MIR of 2,000-in-1 million risk. To understand how to
best address risk within the SOCMI source category, we reviewed
information from our CAA section 114 request for this rulemaking (see
section II.C of this preamble) and identified six facilities that
measured EtO emissions from 14 emission points associated with process
vents and storage vessels. The information gathered for these emission
points indicates that HON sources with EtO emissions from process vents
and storage vessels typically use combustion devices (e.g., thermal
oxidizers) to control EtO emissions. Of these 14 emission points, seven
are controlled by either a thermal incinerator, regenerative thermal
oxidizer, vapor combustion unit, or catalytic oxidation unit; three are
controlled by a scrubber; and the remaining four are uncontrolled.
Based on results from the risk assessment, we determined that the
current MACT standards for HON process vents and storage vessels do not
result in sufficient reductions of EtO emissions to reduce risk to an
acceptable level, and, therefore, we evaluated available control
technologies with a higher level of control, as discussed below.
In the MON final RTR (see 85 FR 49084, August 12, 2020), the EPA
evaluated options to control EtO emissions from process vents and
storage tanks ``in ethylene oxide service'' \50\ regardless of whether
the emission source is classified as Group 1 or Group 2. To reduce EtO
emissions from MON process vents and storage
[[Page 25113]]
tanks in EtO service, the EPA finalized a requirement to either: (1)
Vent 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 process vent and storage tank
vent (or, for multiple process vents, to less than 5 lb/yr for all
combined process vents); or (2) vent emissions through a closed-vent
system to a flare meeting the flare operating requirements discussed in
section III.D.1 of this preamble.
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\50\ In the MON, a process vent in ethylene oxide service means
each batch and continuous 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 would emit uncontrolled, ethylene oxide
emissions greater than or equal to 5 lb/yr (2.27 kg/yr); a storage
vessel in ethylene oxide service means a storage tank of any
capacity and vapor pressure storing a liquid that is at least 0.1
percent by weight of ethylene oxide.
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We are proposing the same ``in ethylene oxide service'' definitions
as used in MON. For process vents, we are proposing 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 are proposing 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 are proposing 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 are also proposing 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.
We are proposing the same MON EtO-specific requirements \51\ in the
HON for HON process vents and storage vessels ``in ethylene oxide
service,'' except that we are proposing to add a requirement that if a
combustion device is used to comply with the concentration standard,
then the concentration must be corrected to 3 percent oxygen to
determine compliance.\52\ Accordingly, to help reduce risk from the
SOCMI source category to an acceptable level, we are proposing that HON
process vents in EtO service either reduce emissions of EtO by: (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 process vent, or to less than 5
pounds per year for all combined process vents; or (2) venting
emissions through a closed vent system to a flare meeting the proposed
flare operating requirements discussed in section III.D.1 of this
preamble (see proposed 40 CFR 63.113(j)). To help reduce risks from the
SOCMI source category to an acceptable level, we are proposing that HON
storage vessels in EtO service either reduce emissions of EtO by: (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 tank vent; or (2)
venting emissions through a closed-vent system to a flare meeting the
proposed flare operating requirements discussed in section III.D.1 of
this preamble (see proposed 40 CFR 63.119(a)(5)). Additionally, we
propose removing the option to allow use of a design evaluation in lieu
of performance testing to demonstrate compliance for storage vessels in
EtO service to ensure that the required level of control is achieved
(see proposed 40 CFR 63.124(a)(1)(i) and (b)(3)). We are also proposing
that after promulgation of the rule, owners or operators that choose to
control emissions with a non-flare control device conduct an initial
performance test according to proposed 40 CFR 63.124 on each existing
control device in EtO service and on each newly installed control
device in EtO service to verify performance at the required level of
control. Additionally, we are proposing at 40 CFR 63.124(b) that owners
or operators conduct periodic performance testing on non-flare control
devices in EtO service every 5 years. Additional information on these
evaluated control options to reduce EtO risk from HON process vents and
storage vessels is found in the document 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, which is available in the docket for this action.
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\51\ See 40 CFR 63.2493.
\52\ We are proposing the concentration correction requirement
because, unlike MON sources with ethylene oxide which were using
scrubber controls, HON sources are generally using combustion
controls for ethylene oxide and a concentration correction for
combustion controls assures dilution with air is not an additional
strategy that facilities could use to bypass control requirements.
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ii. Equipment Leaks
Emissions of EtO from equipment leaks occur in the form of gases or
liquids that escape to the atmosphere through connection points (e.g.,
threaded fittings) or through the moving parts of valves, pumps,
compressors, PRDs, and certain types of process equipment. The
applicable equipment is those components, including pumps, compressors,
agitators, PRDs, sampling collection systems, OEL, valves, and
connectors 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. The equipment leak HON requirements vary by
equipment (component) type but require LDAR using monitoring with EPA
Method 21 of appendix A-7 to 40 CFR part 60 at certain frequencies
(e.g., monthly, quarterly, every 2 quarters, annually) and have varying
leak definitions (e.g., 500 ppm, 1,000 ppm, 10,000 ppm) depending on
the type of service (e.g., gas and vapor service or in light liquid
service). The LDAR requirements for components in heavy liquid service
include sensory monitoring and the use of EPA Method 21 monitoring if a
leak is identified. We provide more details about equipment leaks in
our technology review discussion (see section III.C.6 of this
preamble).
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 equipment leak
emissions of EtO come from these three pieces of equipment. We
identified options to further strengthen LDAR practices for these three
pieces of equipment, including by lowering the leak definitions and/or
requiring more frequent monitoring with EPA Method 21 of 40 CFR part
60, appendix A-7, to find more equipment leaks faster and fix them.
For gas/vapor and light liquid connectors in EtO service, we
identified three options: (1) Require connector monitoring at a leak
definition of 500 ppm with annual monitoring and no reduction in
monitoring frequency (i.e., no skip periods), (2) require connector
monitoring at a leak definition of 100 ppm with annual monitoring and
no reduction in monitoring frequency, and
[[Page 25114]]
(3) require connector monitoring at a leak definition of 100 ppm with
monthly monitoring and no reduction in monitoring frequency.
For light liquid pumps in EtO service, we identified three options:
(1) Lower the leak definition from 1,000 ppm to 500 ppm with monthly
monitoring, (2) lower the leak definition from 1,000 ppm to 100 ppm
with monthly monitoring, or (3) require the use of leakless pumps
(i.e., canned pumps, magnetic drive pumps, diaphragm pumps, pumps with
tandem mechanical seals, pumps with double mechanical seals) with
annual monitoring with a leak definition of any reading above
background concentration levels.
For gas/vapor and light liquid valves in EtO service, we identified
two options: (1) Require a leak definition of 500 ppm with monthly
monitoring and no reduction in monitoring frequency, or (2) lower the
leak definition from 500 ppm to 100 ppm with monthly monitoring and no
reduction in monitoring frequency.
Due to the high residual risk for some of the facilities from
equipment leaks of EtO and the potential need for greater emission
reduction to meet an acceptable level of risk for the SOCMI source
category, we also evaluated a more stringent option that combines
several of the component options. We evaluated the combined option of
requiring monthly monitoring for valves (in gas/vapor and light liquid
service), connectors (in gas/vapor and light liquid service), and pumps
(light liquid service) in EtO service at a leak definition of 100 ppm
for valves and connectors and 500 ppm for pumps using EPA Method 21 of
40 CFR part 60, appendix A-7. This combined option also does not allow
equipment in EtO service to be monitored less frequently with skip
periods nor allow facilities to take advantage of the delay of repair
provisions. Increasing the monitoring frequency to monthly was analyzed
for connectors because they are the most numerous equipment components
at chemical facilities, and they contribute the most to the baseline
emissions from leaking equipment at the EtO emitting facilities.
For the component specific control options, we calculated the EtO
baseline emissions and emissions after implementation of controls for
each facility using average VOC emission rates for each component, and
the component counts and the EtO weight percent of the process from the
responses to the EPA's CAA section 114 request. For the combined option
of monthly monitoring of gas and light liquid valves and connectors at
100 ppm and light liquid pumps at 500 ppm, we do not have emission
factors to estimate reductions for increased monitoring frequencies for
connectors. Where no simplified emission factor method exists to
determine potential reductions of applying the option, we estimated
emissions reductions based on the approach used in other rules,\53\
where detailed leak data was available or where a leak distribution
could be assumed. The equipment leaks model uses a Monte Carlo analysis
to estimate emissions from EtO facility equipment leaks. A detailed
discussion of the model is found in the memorandum Analysis of Control
Options for Equipment Leaks to Reduce Residual Risk of Ethylene Oxide
in the SOCMI Source Category for Processes Subject to HON, which is
available in the docket for this action.
---------------------------------------------------------------------------
\53\ Gas Plant Equipment Leak Monte Carlo Model Code and
Instructions. October 21, 2021. EPA Docket No. EPA-HQ-OAR-2021-0317.
Control Options for Equipment Leaks at Gasoline Distribution
Facilities. October 20, 2021. EPA Docket No. EPA-HQ-OAR-2020-0371.
---------------------------------------------------------------------------
We are proposing the same ``in ethylene oxide service'' definition
for equipment as used in MON.\54\ For equipment leaks, we are proposing
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 HON equipment in EtO
service, in order to achieve greater emissions reductions to help meet
an acceptable level of risk for the SOCMI source category, we are
proposing 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 (see proposed 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 (see proposed 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
(see proposed 40 CFR 63.168(b)(2)(iv) and 40 CFR 63.168(d)(5)).
Additional information on all evaluated control options to reduce EtO
risk from HON equipment leaks is found in the document titled Analysis
of Control Options for Equipment Leaks to Reduce Residual Risk of
Ethylene Oxide in the SOCMI Source Category for Processes Subject to
HON, which is available in the docket for this action.
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\54\ See 40 CFR 63.2550.
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iii. Heat Exchange Systems
Emissions of EtO from heat exchange systems occur when a heat
exchanger's internal tubing material corrodes or cracks, allowing some
process fluids to mix or become entrained with the cooling water.
Pollutants (e.g., EtO) in the process fluids may subsequently be
released from the cooling water into the atmosphere when the water is
exposed to air (e.g., in a cooling tower for closed-loop systems or
trenches/ponds in a once-through system). Heat exchange systems subject
to the HON are required to monitor for leaks of process fluids into
cooling water and take actions to repair leaks within 45 days if they
are detected (and facilities may delay the repair of leaks if they meet
certain criteria). The current HON MACT standard for heat exchange
systems allows the use of any method listed in 40 CFR part 136 to be
used to sample cooling water for leaks for the HAP listed in Table 4 to
subpart F (recirculating systems) and Table 9 to subpart G (once-
through systems) (and other representative substances such as TOC or
VOC that can indicate the presence of a leak can also be used). In
addition, the HON allows facilities to monitor for leaks using a
surrogate indicator of leaks (e.g., ion specific electrode monitoring,
pH, conductivity), provided that certain criteria in 40 CFR 63.104(c)
are met. We provide more details about heat exchange systems in our
technology review discussion (see section III.C.1 of this preamble).
Results from our risk assessment indicate that EtO leaks from heat
exchange systems result in risks of 400-in-1 million at one facility
and 90-in-1 million at another. The HON heat exchange system technology
review (see section III.C.1 of this preamble) identified use of the
Modified El Paso Method as a development in practice for heat exchange
systems at HON-subject facilities. Specifically, we identified the
following control option for heat exchange systems: quarterly
monitoring with the Modified El Paso Method, using a leak action level
defined as a total strippable hydrocarbon concentration (as methane) in
the stripping gas of 6.2 ppmv (and not allowing delay of repair of
leaks for more than 30 days where a total strippable hydrocarbon
concentration (as methane) in the stripping gas of 62 ppmv or higher is
found). This option would also require follow-up monitoring at the same
monitoring location where the leak was identified to ensure that any
leaks found were fixed. For heat exchange systems, we are proposing to
define ``in ethylene oxide
[[Page 25115]]
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. To address the risk from EtO
emissions due to HON heat exchange system leaks, we evaluated the
following option for HON heat exchange systems ``in ethylene oxide
service'': (A) require use of the Modified El Paso Method (see section
III.C.1 of this preamble), (B) increase the Modified El Paso Method
monitoring frequency from quarterly to weekly, (C) reduce the allowed
amount of repair time from 45 days after finding a leak to 15 days from
the sampling date, and (D) prohibit delay of repair. We anticipate this
option would reduce EtO emissions from leaking heat exchange systems by
93 percent because leaks would be identified and repaired quicker, and
this is needed to help reduce risk from the SOCMI source category. For
this reason, we are proposing to require weekly monitoring for leaks
for heat exchange systems in EtO service using the Modified El Paso
Method (see proposed 40 CFR 63.104(g)(6)), and if a leak is found, we
are proposing 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 (see proposed
40 CFR 63.104(h)(6)). Additional information on this evaluated control
option to reduce EtO risk from HON heat exchange systems is found 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, which is available in the docket
for this action.
iv. Wastewater
EtO is emitted into the air from wastewater collection, storage,
and treatment systems that are uncovered or open to the atmosphere
through volatilization of the compound at the liquid surface. Emissions
occur by diffusive or convective means, or both. Diffusion occurs when
organic pollutant concentrations at the water surface are much higher
than ambient concentrations. The organic pollutants volatilize, or
diffuse into the air, to reach equilibrium between the aqueous and
vapor phases. Convection occurs when air flows over the water surface,
sweeping organic vapors from the water surface into the air. The rate
of volatilization is related directly to the speed of the air flow over
the water surface.
The current HON standards divide wastewater streams into Group 1
wastewater streams, which require controls, and Group 2 wastewater
streams, which generally do not require controls provided they do not
exceed Group 1 thresholds. The Group 1 and Group 2 designations for
wastewater streams are based on volumetric flow rate and total annual
average organic HAP concentration. The HON specifies performance
standards for treating Group 1 wastewater streams using open or closed
biological treatment systems or using a design steam stripper with vent
control. For APCDs (e.g., thermal oxidizers) used to control emissions
from collection system components, steam strippers, or closed
biological treatment, the HON provides owners or operators several
compliance options, including 95 percent destruction efficiency, a 20
ppmv outlet concentration, or design specifications for temperature and
residence time. We provide more details about wastewater streams in our
technology review discussion (see section III.C.5 of this preamble).
Results from our risk assessment indicate that EtO emissions from
wastewater result in risks of 200-in-1 million at one facility and 70-
in-1 million at another. For wastewater, we are proposing 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 part per million by weight at any flow
rate. To help reduce the risk from EtO emissions to an acceptable
level, we are proposing that owners and operators of HON sources manage
and treat any wastewater streams that are ``in ethylene oxide service''
(see proposed 40 CFR 63.132(c)(1)(iii) and (d)(1)(ii)) as they would a
Group 1 wastewater stream. Additional information on this evaluated
control option to reduce EtO risk from HON wastewater streams is found
in 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, which is available in the docket
for this action.
Finally, we are aware of at least two HON-subject facilities that
reported EtO emissions from heat exchange systems due to disposing EtO
entrained water (e.g., condensate water, quench and glycol bleeds) into
their cooling water. While these are not ``leaks'' from heat exchange
systems, this water is being combined with water in heat exchange
systems that should actually be considered a potential source of
wastewater, as it contains EtO. One of these facilities reported
approximately 2.5 tpy EtO were released to the atmosphere in 2017 from
this activity; the other facility reported about 0.5 tpy EtO emissions
(for 2017) from a similar activity. In order to help reduce risk from
the SOCMI source category to an acceptable level, and in an effort to
eliminate these types of EtO emissions from wastewater being injected
into heat exchange systems, we are also proposing 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 (see proposed 40 CFR
63.104(k)).
v. Maintenance Vents
We are proposing the new term ``maintenance vent'' for process
vents that are only used as a result of startup, shutdown, maintenance,
or inspection of equipment where equipment is emptied, depressurized,
degassed, or placed into service. We provide more details about
maintenance vents in section III.D.4 of this preamble. We identified
three HON-subject facilities that reported EtO emissions from
maintenance vents in their 2017 NEI from HON processes that use and
emit EtO. We determined that, in order to help reduce EtO risk from the
SOCMI source category to an acceptable level, facilities would need to
limit their amount of EtO being emitted through maintenance vents
(i.e., equipment openings). For this reason, we are proposing 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 (see proposed 40 CFR 63.113(k)(4)). We based this proposed limit
on the largest amount of EtO emissions reported in the 2017 NEI for all
maintenance vents combined at any single HON-subject facility (i.e.,
one facility reported about 1 ton of EtO from maintenance activities
which corresponded to 80-in-1 million risk). Facilities could use a
portable thermal oxidizer to control excess EtO emissions from their
maintenance vents in order to meet the proposed 1.0 tpy EtO maintenance
vent limit; \55\ however,
[[Page 25116]]
based on the 2017 NEI, we anticipate that all HON-subject facilities
with processes that use and emit EtO can already meet this proposed
emissions limit without additional control.
---------------------------------------------------------------------------
\55\ We surmised that a portable thermal oxidizer is a
reasonable control option for maintenance vents because it would
require a significant effort to identify and characterize each
potential release point to install permanent APCDs.
---------------------------------------------------------------------------
vi. Flares
We determined that to achieve an acceptable level of risk,
facilities need to limit the amount of ethylene oxide they are emitting
from flaring from all HON emission sources at their facility, even
after applying the control options for the other HON emission sources
that we evaluated to reduce risk to an acceptable level. This
determination is supported by the fact that there is one facility with
a risk of 500-in-1 million from flaring EtO and another facility with
risk of 90-in-1 million as a result of this same operation. Therefore,
we are proposing a requirement 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
(see proposed 40 CFR 63.108(p)).
We identified nine HON-subject facilities that reported the use of
flares in their 2017 NEI to control EtO emissions from HON processes
that use and emit EtO. Two of these facilities each reported about two
times more EtO emissions from their flares than the reported EtO
emissions from all the other seven HON-subject facilities combined.
Based on this reported emissions data, the highest risk source for
flaring emitted a combined total of 2.87 tpy of EtO from its flares. In
order to reduce the HON risk to an acceptable level, the EtO emissions
from all flares would need to be less than or equal to 0.40 tpy (in
addition to complying with other standards designed to reduce risk to
an acceptable level). Assuming 98 percent flare control efficiency and
back-calculating an EtO waste gas flare load, the maximum inlet load to
all flares combined would need to be 20 tpy. Using the reported EtO
emissions of 2.87 tpy from the highest emitting facility, we estimate
that the facility's current combined total EtO load to flares is about
143.5 tpy, and that the facility would need to reduce the combined
total EtO load to their flares by about 124 tpy to meet the EtO load
limit of 20 tpy. For these reasons, we are proposing a requirement 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 (see proposed
40 CFR 63.108(p)) to get to an acceptable level of risk from all HON
emission sources at a facility. A more thorough discussion of this
analysis is included in the document titled Analysis of Control Options
for Flares to Reduce Residual Risk of Ethylene Oxide in the SOCMI
Source Category for Processes Subject to HON, which is available in the
docket for this action.
vii. PRDs
The HON currently regulates PRDs through equipment leak provisions
that are applied only after the pressure release event relief occurs
(i.e., conduct monitoring with EPA Method 21 of Appendix A-7 to 40 CFR
part 60 after each pressure release using a leak definition of 500 ppm)
to ensure they are properly reseated and not leaking after a PRD
release occurs; however, these provisions do not apply to an emissions
release from a PRD (see section III.D.2 of this preamble for more
detail). As previously discussed in section III.B.2.a.i of this
preamble, we are aware of some instances where PRD releases of EtO
emissions occurred for gas streams that would otherwise be treated as
process vents. These PRD releases contribute to a large portion of the
2000-in-1 million MIR (i.e., 75 percent) that we are proposing is
unacceptable. While the EPA is proposing to set work practice standards
for PRD releases (see section III.D.2 of the preamble), in order to
help reduce risk from the SOCMI source category to an acceptable level
we are also proposing 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.
viii. Summary
For process vents, storage vessels, equipment leaks, heat exchange
systems, wastewater, maintenance vents, flares, and PRDs, we considered
the control options described above for reducing EtO risk from the
SOCMI source category that are associated with processes subject to the
HON. To reduce risk from the source category to an acceptable level, we
propose to require 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'' (defined in this
proposal). We are also proposing requirements to reduce EtO emissions
from maintenance vents, flares, and PRDs. For process vents and storage
vessels in EtO service, we are proposing 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 are proposing 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 are proposing 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 are proposing to revise
the Group 1 wastewater stream threshold for sources to include
wastewater streams in EtO service. For maintenance vents, we are
proposing 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 are proposing 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 are
proposing that any atmospheric PRD release is a violation of the
standard.
In all cases, we are proposing that if information exists that
suggests EtO could be present in these processes, then the emission
source is considered to be in EtO service unless sampling and analysis
is performed to demonstrate that the emission source does not meet the
definition of being in EtO service. We are proposing sampling and
analysis procedures at 40 CFR 63.109. Examples of information that
could suggest EtO is present in a process 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.
Based on the proposed applicability thresholds, we expect that up
to 17 facilities will be affected by one or more
[[Page 25117]]
of the proposed EtO-specific standards; and we anticipate that all of
these facilities will be subject to the process vent, storage vessel,
equipment leak, wastewater, and PRD provisions. We do not expect any
facility to be impacted by the proposed 1.0 tpy maintenance vent EtO
emission limit, and only two facilities will be affected by the
proposed 20 tpy EtO flare load limit, although all facilities will be
required to comply with these standards.
b. Chloroprene Controls for P&R I Neoprene Production Processes
i. Process Vents and Storage Vessels
Results from our risk assessment indicate that for the Neoprene
Production source category, 65 percent of the risk presented by
neoprene production processes (i.e., 300-in-1 million) and 12 of the
17.5 tpy of chloroprene in the reported emissions inventory are from
emissions associated with reaction processes and supporting equipment,
and storage vessels at the one neoprene production facility.
Specifically, 58 percent of the risk is associated with emissions from
the polymer building wall fans housing much of the operations for
creating neoprene, of which most of the emissions are from the opening
of the polymer reactors and straining of coagulate generated after the
batch polymerization occurs to make neoprene; 5 percent of the risk is
from emissions from unstripped emulsion storage vessels as they are
being opened and/or degassed; and 2 percent of the risk is from
emissions from the wash belt dryers. An additional 18 percent of the
risk is from wastewater sources, which are discussed in III.B.2.b.ii of
this preamble.
For process vents, we are proposing to define ``in chloroprene
service'' in P&R I 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, we are proposing to define ``in
chloroprene service'' in P&R I at 40 CFR 63.482 to mean 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, which would require control of the unstripped
resin storage vessels and emissions from opening or degassing of these
sources. Additionally, we are proposing 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 are proposing to require emissions from
process vents and storage vessels in chloroprene service be routed to a
closed vent system to a non-flare control device that reduces
chloroprene by greater or equal to 99.9 percent by weight, or to a
concentration less than 1 ppmv for each process vent or storage vessel
vent, or less than 5 pounds per year for all combined process vents.
(see proposed 40 CFR 63.484(u)(1), 40 CFR 63.485(y)(1), and 40 CFR
63.487(j)(1)). Our proposed approach would require control of process
vent emissions from batch polymer reactors that the one neoprene
facility has already voluntarily controlled (but that are not currently
required to be controlled in P&R I) and that are considered in the
baseline emissions of our risk assessment. These proposed standards
would also capture emissions from the emulsion storage vessels,
strainers, and wash belt dryers. We 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). We costed
out permanent total enclosures, a thermal oxidizer, and ductwork and
associated support equipment using the procedures in EPA's Control Cost
Manual. Enclosing and routing vapors to a thermal oxidizer is expected
to achieve at least 99.9 percent reduction in chloroprene emissions
from the storage vessels and wash belt dryers. Due the openness of the
polymer building and other emission sources that could contribute to
emissions coming from the polymer building overall, we estimate that 90
percent of the chloroprene emissions will be collected in the
enclosures and be reduced by at least 99.9 percent in the thermal
oxidizer. The result of the control option is to reduce chloroprene
emissions and risk from the polymer building, unstripped resin emulsion
storage vessels, and the wash belt dryers from 12 tpy to 0.7 tpy.
Because of concerns that some of these emission sources may not
necessarily be considered process vents or emissions regulated for
storage vessels (e.g., since we are assuming permanent total enclosures
will be needed to collect these emissions since they could be
fugitive), we are also proposing a facility-wide chloroprene emissions
cap for all neoprene production emission sources as a backstop, the
result of which is based on our post-control emissions and risk for all
neoprene emission sources emitting chloroprene that are reported in the
emissions inventory and which is discussed in section III.B.2.b.v of
this preamble.
Additional information on this evaluated control option to reduce
chloroprene risk from fugitives from polymer batch reactors, emulsion
storage vessels, strainers, and wash belt dryers with affected P&R I
sources producing neoprene is found in the document titled 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, which is available in the docket for this action.
ii. Wastewater
Chloroprene is emitted into the air from wastewater collection,
storage, and treatment systems that are uncovered or open to the
atmosphere through volatilization of the compound at the liquid
surface. Emissions occur by diffusive or convective means, or both.
Diffusion occurs when organic concentrations at the water surface are
much higher than ambient concentrations. The organics volatilize, or
diffuse into the air, to reach equilibrium between aqueous and vapor
phases. Convection occurs when air flows over the water surface,
sweeping organic vapors from the water surface into the air. The rate
of volatilization is related directly to the speed of the air flow over
the water surface.
Similar to the HON, as discussed in section III.B.2.a.iv of this
preamble, the current P&R I standards divide wastewater streams into
Group 1 wastewater streams, which require controls, and Group 2
wastewater streams, which generally do not require controls provided
they remain below Group 1 thresholds. The Group 1 and Group 2
designations for wastewater streams are based on volumetric flow rate
and total annual average organic HAP concentration. P&R I specifies
performance standards for treating Group 1 wastewater streams using
open or closed biological treatment systems or using a design steam
stripper with vent control. For APCDs (e.g., thermal oxidizers) used to
control emissions from collection system components, steam strippers,
or closed biological treatment, P&R I provides owners or
[[Page 25118]]
operators several compliance options, including 95 percent destruction
efficiency, a 20 ppmv outlet concentration, or design specifications
for temperature and residence time. We provide more details about
wastewater streams in our technology review.
Results from our risk assessment indicate that, for the Neoprene
Production source category, 18 percent of the risk (i.e., 80-in-1
million) and 2.6 of the 17.5 tpy of chloroprene in the reported
emissions inventory are from emissions associated with wastewater. For
wastewater, we are proposing to define ``in chloroprene service'' in
P&R I 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 address the risk from chloroprene
emissions related to wastewater associated with affected P&R I sources
producing neoprene, we are proposing that owners and operators manage
and treat any existing wastewater streams that are ``in chloroprene
service'' (see proposed 40 CFR 63.501(a)(10)(iv)) as they would a Group
1 wastewater stream. Additional information on this evaluated control
option to reduce chloroprene risk from wastewater streams associated
with affected P&R I sources producing neoprene is found 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, which is available in the docket for this action.
Finally, for consistency with our proposal for the HON to eliminate
EtO emissions from wastewater being injected into heat exchange systems
(see section III.B.2.a.iv of this preamble), we are also proposing 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 (see proposed 40 CFR 63.502(n)(8)). The result
of all these wastewater controls will reduce chloroprene emissions from
wastewater from 2.6 tpy to 0.18 tpy in the reported emissions
inventory.
iii. Maintenance Vents
We are proposing at 40 CFR 63.485(x) and 40 CFR 63.487(i) the new
term ``maintenance vent'' for process vents that are only used as a
result of startup, shutdown, maintenance, or inspection of equipment
where equipment is emptied, depressurized, degassed, or placed into
service. We provide more details about maintenance vents in section
III.D.4 of this preamble as well. We evaluated the option of limiting
the amount of chloroprene that a neoprene production facility can emit
annually through maintenance vents (i.e., equipment openings). Using
their reported emissions, we determined that in order to reduce the
neoprene source category risk to an acceptable level, the one neoprene
production facility would need to (in addition to complying with other
standards designed to reduce chloroprene risk) maintain its combined
total chloroprene maintenance vent emission releases at less than or
equal to 1.0 tpy. For this reason, we are proposing a requirement that
owners and operators cannot release more than 1.0 tons of chloroprene
from all maintenance vents combined in any consecutive 12-month period
(see proposed 40 CFR 63.485(z) and 40 CFR 63.487(i)(4)). We note that,
based on reported emissions, the neoprene production facility is
already meeting this proposed 1.0 tpy chloroprene maintenance vent
limit from its neoprene processes.\56\
---------------------------------------------------------------------------
\56\ From reported Neoprene Unit Condition XVII permitted
emissions.
---------------------------------------------------------------------------
iv. PRDs
P&R I currently regulates PRDs through equipment leak provisions
that are applied only after the pressure release event relief occurs
(i.e., conduct monitoring with EPA Method 21 of Appendix A-7 to 40 CFR
part 60 after each pressure release using a leak definition of 500 ppm)
to ensure they are properly reseated and not leaking after a PRD
release occurs; however, these provisions do not apply to an emissions
release from a PRD (see section III.D.2 of this preamble for more
detail). While we are not aware of PRD releases occurring from the
Neoprene Production source category, we are concerned that allowing
them could compound already unacceptable risk. Thus, while the EPA is
proposing to set work practice standards for PRD releases (see section
III.D.2 of the preamble), given the high potential risk posed by
chloroprene from PRD releases, we are also proposing at 40 CFR
63.165(e)(3)(v)(D) (by way of proposed 40 CFR 63.502(a)(2)) that any
release event from PRDs in chloroprene service in the Neoprene
Production source category facilities is a violation of the standard.
This is the same provision that we finalized in the MON for PRDs in EtO
service (see 40 CFR 63.2493(d)(4)(iv)), and that we are proposing for
HON PRDs in EtO service, to ensure that these emissions are controlled
and do not bypass controls.
v. Summary
For process vents, storage vessels, wastewater, maintenance vents,
and PRDs, we considered the control options described above for
reducing chloroprene risk from the Neoprene Production source category.
To reduce risk from the source category to an acceptable level, we
propose to require control of chloroprene for: (1) Process vents, (2)
storage vessels, and (3) wastewater ``in chloroprene service'' (defined
in this proposal). We are also proposing requirements to reduce
chloroprene emissions from maintenance vents and PRDs. For process
vents and storage vessels in chloroprene service, we are proposing
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 are proposing to revise the Group
1 wastewater stream threshold for sources to include wastewater streams
in chloroprene service. For maintenance vents, we are proposing 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 are proposing that
any atmospheric PRD release is a violation of the standard. Lastly, in
order to ensure reductions in emissions and risk given that many
sources within the neoprene process are fugitive in nature, we are also
proposing a facility-wide chloroprene emissions cap for all neoprene
production emission sources as a backstop. After application of the
proposed controls to address unacceptable risk for process vents,
storage vessels, wastewater, maintenance vents, and PRDs, and including
remaining sources of emissions in the emissions inventory (e.g.,
equipment leaks), we are proposing at 40 CFR 63.483(a)(10) a facility-
wide chloroprene emissions cap of 3.8 tpy in any consecutive 12-month
period for all neoprene production emission sources.
In all cases, we are proposing that if information exists that
suggests chloroprene could be present in these processes, then the
emission source is considered to be in chloroprene service unless
sampling and analysis is performed to demonstrate that the
[[Page 25119]]
emission source does not meet the definition of being in chloroprene
service. We are proposing sampling and analysis procedures at 40 CFR
63.509. Examples of information that could suggest chloroprene is
present in a process stream include calculations based on safety data
sheets, material balances, process stoichiometry, or previous test
results provided that the results are still relevant to the current
operating conditions.
Based on the proposed applicability thresholds, we expect that only
one facility (i.e., the neoprene production facility) will be affected
by the proposed chloroprene-specific standards, and we anticipate that
this facility will be subject to the process vent, storage vessel,
wastewater, maintenance vent, and PRD provisions.
3. Determination of Risk Acceptability After Proposed Emission
Reductions
As noted in sections II.A.1 and II.E of this preamble and in the
1989 Benzene NESHAP, the EPA sets standards under CAA section 112(f)(2)
using a two-step approach, with an analytical first step to determine
whether risks are acceptable. This determination ``considers 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 38044, 38045/col. 1, September
14, 1989). In the 1989 Benzene NESHAP, the EPA explained that ``[i]n
establishing a presumption for MIR, rather than a rigid line for
acceptability, the Agency intends to weigh it with a series of other
health measures and factors'' (id., at 38045/ col. 3). ``As risks
increase above this benchmark, they become presumptively less
acceptable under section 112, and would be weighed with the other
health risk measures and information in making an overall judgement on
acceptability'' (id.).
a. SOCMI
Presented in the Table 4 of this preamble are the levels of
emissions control proposed to address unacceptable risks for the SOCMI
source category. This includes reducing emissions of EtO for HON
processes and requiring more stringent controls for process vents,
storage vessels, equipment leaks, heat exchange systems, wastewater,
maintenance vents, flares, and PRDs without considering costs.
Table 4--Nationwide EtO Risk Impact Control Options for the SOCMI Source
Category
------------------------------------------------------------------------
Percent
Emission source Description of reduction of EtO
proposed option emissions
------------------------------------------------------------------------
Process Vent Controls \1\..... Control emissions 99.9 percent.
through a closed-vent
system to a non-flare
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.
Storage Vessel Controls \1\... Control emissions 99.9 percent.
through a closed-vent
system to a non-flare
control device that
reduces EtO by
greater than or equal
to 99.9 percent by
weight or to a
concentration less
than 1 ppmv.
Equipment Leak Controls....... Monthly M21 monitoring 70-74 percent.
of valves and
connectors with a 100
ppm leak definition
and monthly
monitoring of pumps
at 500 ppm leak
definition without
skip periods or delay
of repair for these
pieces of equipment
that are in EtO
service.
Heat Exchange Systems Controls Weekly monitoring for 93 percent.
leaks using the
Modified El Paso
Method and repair of
leaks required no
later than 15 days
after date of weekly
sampling occurs.
Wastewater Controls........... Control all wastewater 98 percent.
with a total annual
average concentration
of EtO greater than
or equal to 1 ppmw at
any flow rate as if
it were Group 1
wastewater.
Maintenance Vent Emission Cap. 1.0 tpy limit......... Proposing to
limit to
existing level
in emissions
inventory.
Flare Load Limit.............. 20 tpy limit on amount Site specific
of EtO that could be and would
sent to a flare. likely require
two facilities
to use a 99.9
percent control
rather than a
flare achieving
98 percent.
PRD releases.................. Work practice Assumed 99.9
standards make percent
atmospheric releases control, as it
from PRDs in EtO would be
service a violation controlled as a
from the standard. process vent.
------------------------------------------------------------------------
\1\ Flares may also be used up to the flare load limit, though we do not
expect this to occur given facilities would need to meet these more
stringent control requirements after reaching the 20 tpy load limit.
For the SOCMI source category, after implementation of the proposed
controls to address unacceptable risks, the MIR is reduced to 100-in-1
million (down from 2,000-in-1 million) with no facilities or
populations exposed to risk levels greater than 100-in-1 million. The
total population exposed to risk levels greater than or equal to 1-in-1
million living within 50 km (~31 miles) of a facility would be reduced
from 7.2 million people to 5.7 million people. The total estimated
cancer incidence of 2 drops to 0.4 excess cancer cases per year. The
maximum modeled chronic noncancer TOSHI for the source category remains
unchanged. It 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 remain
unchanged, with a maximum modeled acute HQ of 3 based on the RELs for
chlorine and acrolein. Table 5 of this preamble summarizes the
reduction in cancer risks based on the proposed controls.
[[Page 25120]]
Table 5--Cancer Risks After Implementation of Proposed Control for the SOCMI Source Category
----------------------------------------------------------------------------------------------------------------
MIR (x-in-1 Population (>=1- Population (>100-
Control scenario million) in-1 million) in-1 million) Cancer incidence
----------------------------------------------------------------------------------------------------------------
Pre-Control Baseline............... 2,000 7,200,000 87,000 2
Post-Control....................... 100 5,700,000 0 0.4
----------------------------------------------------------------------------------------------------------------
As noted earlier in this section, the EPA considers an MIR of
``approximately 1-in-10 thousand'' (i.e., 100-in-1 million) to be the
presumptive limit of acceptability (54 FR 38045, September 14, 1989)
and the proposed controls lower the MIR to 100-in-1 million. This is a
significant reduction from the pre-control MIR of 2,000-in-1 million.
For noncancer effects, the EPA has not established under section 112 of
the CAA a numerical range for risk acceptability as it has with
carcinogens, nor has it determined that there is a bright line above
which acceptability is denied. However, the Agency has established
that, as exposure increases above a reference level (as indicated by a
HQ or TOSHI greater than 1), confidence that the public will not
experience adverse health effects decreases and the likelihood that an
effect will occur increases.
In considering the potential implications of HIs above 1 (and equal
to 2) for chlorine and maleic anhydride emissions, we note the basis
and development of the underlying noncancer health benchmarks. Both
chlorine and maleic anhydride are portal of entry irritants that, with
sufficient exposure, act as potent irritants of the eyes and
respiratory tract. Chronic exposure in human workers has been
associated with airflow obstruction and asthma-like attacks, indicating
a potential for people with asthma to have greater sensitivity to
effects of these pollutants. The health benchmarks for chlorine and
maleic anhydride represent exposure levels at (and below) which there
is not likely to be appreciable risk of deleterious effects over a
lifetime exposure, including for sensitive groups; however, the EPA has
not estimated an exposure level at and above which an appreciable risk
of deleterious effects would be expected.
In the case of chlorine, the sensitive effect on which the
benchmark is based is an increased risk of nasal lesions. The chronic
exposure level at which this effect, which was observed in an
experimental animal study, is estimated is 0.004 mg/m\3\.\57\ \58\ In
the case of maleic anhydride, the sensitive effect is the occurrence of
mild hyperplasia in the nasal epithelium.59 60 The chronic
exposure level at which this effect, which was observed in several
experimental animal studies, is estimated is 0.021 mg/m\3\. To derive
the chronic health benchmarks, both of these human equivalent exposure
values were divided by 30 to account for the potential for people to be
more sensitive than animals and for some population groups, such as
people with asthma, to be more sensitive than the general population.
---------------------------------------------------------------------------
\57\ Agency for Toxic Substances and Disease Registry (ATSDR).
2010. Toxicological profile for Chlorine. Atlanta, GA: U.S.
Department of Health and Human Services, Public Health Service.
\58\ Klonne DR, Ulrich CE, Riley MG, et al. 1987. One-year
inhalation toxicity study of chlorine in Rhesus monkeys (Macaca
mulatta). Fundam Appl Toxicol 9:557-572.
\59\ Office of Environmental Health Hazard Assessment (OEHHA).
2008. Technical Supporting Document for Noncancer RELs, Appendix D3.
\60\ Short RD, Minor JL, Winston JM, Seifter J, and Lee C. 1978.
Inhalation of ethylene dibromide during gestation by rats and mice.
Toxicol. Appl. Pharmacol. 46:173-182.
---------------------------------------------------------------------------
For both chlorine and maleic hydride, we note the small size of the
HI (2) in relation to the total uncertainty factor of 30 used in
derivation of both health benchmarks. In so doing, we also note a
somewhat reduced confidence in a conclusion that exposure at these
levels is without appreciable risk due to uncertainty, particularly for
sensitive populations. Finally, we note that the population exposed to
a TOSHI greater than 1 is relatively small (83 people).
Therefore, considering all health information, including risk
estimation uncertainty, the EPA proposes that the resulting risks after
implementation of the proposed controls for the SOCMI source category
detailed in Section III.B.2.a. would be acceptable. We solicit comment
on all the proposed control requirements to reduce risk to an
acceptable level for the SOCMI source category.
b. Neoprene Production
Presented in Table 6 of this preamble are the levels of emissions
control proposed to address unacceptable risks for the Neoprene
Production source category. This includes emission reductions of
chloroprene from process vents, storage vessels, wastewater,
maintenance vents, and PRDs without considering costs, as well as a
facility-wide emissions cap for chloroprene from all Neoprene
Production emission sources.
Table 6--Nationwide Chloroprene Risk Impact Control Options for the
Neoprene Production Source Category
------------------------------------------------------------------------
Percent
Description of reduction of
Emission source proposed option chloroprene
emissions
------------------------------------------------------------------------
Process Vent Controls......... Control emissions 99.9 percent.
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. This includes
also capturing and
controlling emissions
from opening of the
polymer reactors and
strainers.
Storage Vessel Controls....... Control emissions 99.9 percent.
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. This
includes also
capturing and
controlling emissions
from opening and/or
degassing of the
unstripped resin
emulsion tanks.
[[Page 25121]]
Wastewater Controls........... Control all wastewater 93 percent.
with a total annual
average concentration
of chloroprene
greater than or equal
to 10 ppmw at any
flow rate as if it
were Group 1
wastewater.
Maintenance Vent Emission Cap. 1.0 tpy limit......... Proposing to
limit to
existing level
in emissions
inventory.
PRD releases.................. Work practice None were
standards make reported in
atmospheric releases emissions
from PRDs in inventory,
chloroprene service a proposing
violation from the standard to
standard. ensure this
remains the
case.
Facility-wide emissions cap 3.8 tpy limit, which 79 percent.
for chloroprene from all is a backstop to
Neoprene Production emission ensure reductions in
sources. emissions and risk
given that many
sources within the
neoprene process are
fugitive.
------------------------------------------------------------------------
For the Neoprene Production source category, after implementation
of the proposed controls to address unacceptable risks, the MIR is
reduced to 100-in-1 million (down from 500-in-1 million) with zero
people exposed to risk levels greater than 100-in-1 million. The total
population exposed to risk levels greater than or equal to 1-in-1
million living within 50 km (~31 miles) of the facility would be
reduced from 690,000 people to 48,000 people. The total estimated
cancer incidence of 0.05 drops to 0.008 excess cancer cases per year.
Table 7 of this preamble summarizes the reduction in cancer risks based
on the proposed controls.
Table 7--Nationwide Risk Impacts After Implementation of Proposed Controls for the Neoprene Production Source
Category
----------------------------------------------------------------------------------------------------------------
MIR (x-in-1 Population (>=1- Population (>100-
Control scenario million) in-1 million) in-1 million) Cancer incidence
----------------------------------------------------------------------------------------------------------------
Pre-Control Baseline................ 500 690,000 2,100 0.05
Post-Control........................ 100 48,000 0 0.008
----------------------------------------------------------------------------------------------------------------
Again, as noted earlier in this section, the EPA considers an MIR
of ``approximately 1-in-10 thousand'' (i.e., 100-in-1 million) to be
the presumptive limit of acceptability (54 FR 38045, September 14,
1989) and the proposed controls lower the MIR to 100-in-1 million, a
significant reduction in the pre-control MIR of 500-in-1 million.
Therefore, after implementation of the proposed controls for the
Neoprene Production source category detailed in Section III.B.2.a. and
considering all health information, including risk estimation
uncertainty, the EPA proposes that the resulting risks would be
acceptable for the Neoprene Production source category. We solicit
comment on all the proposed control requirements to reduce risk to an
acceptable level for the source category.
4. Ample Margin of Safety Analysis
The second step in the residual risk decision framework is a
determination of whether the emission standards proposed to achieve an
acceptable risk level provide an ample margin of safety to protect
public health, or whether more stringent emission standards would be
required for this purpose. In making this determination, we considered
the health risk and other health information considered in our
acceptability determination, along with additional factors not
considered in the risk acceptability step, including costs and economic
impacts of controls, technological feasibility, uncertainties, and
other relevant factors, consistent with the approach of the 1989
Benzene NESHAP. Table 8 of this preamble presents the summary of costs
and EtO emission reductions we estimated for the proposed control
requirements to get the risks to an acceptable level for the SOCMI
source category. 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; and
Analysis of Control Options for Flares to Reduce Residual Risk of
Ethylene Oxide in the SOCMI Source Category for Processes Subject to
HON, which are available in the docket for this rulemaking. We note
that for two fugitive EtO emission sources (i.e., equipment leaks and
wastewater), emission reductions (and subsequent cost-effectiveness
values for EtO) differ from reductions expected to occur from reported
emissions inventories due to use of model plants, engineering
assumptions made to estimate baseline emissions, and uncertainties in
how fugitive emissions may have been calculated for reported
inventories compared to our model plants analyses (and are documented
in the aforementioned technology review memorandum).
[[Page 25122]]
Table 8--Nationwide EtO Emission Reductions and Cost Impacts for Control Options Considered for HON Processes
----------------------------------------------------------------------------------------------------------------
Total capital Total EtO emission Cost
Control option investment annualized reductions effectiveness
(MM$) costs (MM$/yr) (tpy) ($/ton EtO)
----------------------------------------------------------------------------------------------------------------
A--Process Vent & Storage Vessel Controls....... 10.2 5.28 32.0 165,000
B--Equipment Leak Controls...................... 0.18 3.53 42.3 83,500
C--Heat Exchange System Controls................ 0.043 0.19 6.06 31,400
D--Wastewater Controls.......................... 65.8 41.1 396 103,800
E--Maintenance Vent Emission Cap \1\............ 0.017 0.0027 0 N/A
F--Flare Load Limit............................. 0.28 0.46 5.04 91,300
---------------------------------------------------------------
Total (A + B + C + D + E + F)............... 76.5 50.6 481 105,000
----------------------------------------------------------------------------------------------------------------
\1\ We anticipate that all facilities with HON processes that use and emit EtO can already meet the proposed
maintenance vent emissions limit without additional control, thus only minimal costs are included.
Table 9 of this preamble presents the summary of costs and
chloroprene emission reductions we estimated for the proposed control
options to get the risks to an acceptable level for the Neoprene
Production source category. 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 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, which are available in
the docket for this rulemaking. We note that chloroprene emission
reductions from wastewater (and subsequent cost-effectiveness values
for chloroprene from wastewater) differ from reductions expected to
occur from reported emissions inventories due to use of model plants,
engineering assumptions made to estimate baseline emissions, and
uncertainties in how fugitive emissions may have been calculated for
reported inventories compared to our model plants analysis (and are
documented in the aforementioned memorandum).
Table 9--Nationwide Chloroprene Emission Reductions and Cost Impacts for Control Options Considered for P&R I
Processes Producing Neoprene
----------------------------------------------------------------------------------------------------------------
Chloroprene Cost
Total capital Total emission effectiveness
Control option investment annualized reductions ($/ton
(MM$) costs (MM$/yr) (tpy) chloroprene)
----------------------------------------------------------------------------------------------------------------
A--Process Vent, Storage Vessel, & Maintenance 10.1 2.80 11.3 247,800
Vent Controls..................................
B--Wastewater Controls.......................... 5.84 7.56 17.7 427,000
---------------------------------------------------------------
Total (A + B)............................... 15.9 10.4 29.0 359,000
----------------------------------------------------------------------------------------------------------------
For the ample margin of safety analyses, we evaluated the cost and
feasibility of available control technologies that could be applied to
HON processes and neoprene production processes to reduce risks
further, considering all of the health risks and other health
information considered in the risk acceptability determination
described above and the additional information that can be considered
only in the ample margin of safety analysis (i.e., costs and economic
impacts of controls, technological feasibility, uncertainties, and
other relevant factors). We note that the EPA previously made a
determination that the standards for the SOCMI source category and
Neoprene Production source category provide an ample margin of safety
to protect public health, and that the most significant changes since
that determination were 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 these two
pollutants since EtO, even after application of controls needed to get
risks to an acceptable level, drives cancer risk and cancer incidence
(i.e., 60 percent of remaining cancer incidence is from EtO) for the
SOCMI source category and almost all the remaining cancer risk and
cancer incidence (i.e., 99.995 percent of remaining cancer incidence)
is from chloroprene for the Neoprene Production source category.
For the SOCMI source category, no other control options for EtO
were identified beyond those proposed to reduce risks to an acceptable
level. Furthermore, the proposed EtO controls for process vents,
storage vessels, equipment leaks, heat exchange systems, wastewater,
and PRDs to reduce risks to an acceptable level are far more stringent
than other options we identified to control HAP generally (i.e., see
sections III.C and III.D of this preamble).
For chloroprene emissions from HON-subject sources, we identified
control options for equipment leaks and maintenance activities in our
review of these standards (see sections III.C.6 and III.D.4 of this
preamble). These controls would likely reduce the cancer incidence and
number of people exposed to risks greater than or equal to 1. However,
the overall source category risk reductions would be relatively small.
Only approximately 3 percent of the SOCMI source category cancer
incidence after the proposed controls in section III.B.2 to reduce
risks to an acceptable level is due to chloroprene emissions. Also, of
the 5.7 million people with cancer risks greater than or equal to 1-in-
1 million after the proposed controls to reduce risks to an
[[Page 25123]]
acceptable level, approximately 48,000 people (or 0.8 percent of the
total) have risks greater than or equal to 1-in-1 million due to
chloroprene emissions from the SOCMI source category. However, as
described in sections III.C.6 and III.D.4, the options we evaluated for
equipment leaks and maintenance activities beyond the standards
currently in the HON (or that are being proposed for maintenance
activities) are not cost-effective.
For the Neoprene Production source category, we did not identify
control options for chloroprene emissions from process vents, storage
vessels, wastewater, maintenance vents, and PRDs that reduced emissions
beyond those proposed in section III.B.2 to reduce risks to an
acceptable level. We also considered other potential sources of
chloroprene, in particular heat exchange systems and equipment leaks.
For heat exchange systems, no chloroprene emissions were reported in
the emissions inventory from this source and as such, no risk
reductions would be realized by requiring more stringent controls. For
equipment leaks, additional control options were identified that could
reduce risks further from this source and are discussed as part our
technology review (see section III.C.6 of this preamble). The options
would reduce chloroprene equipment leak emissions by 10-20 percent.
Approximately 14 percent of the Neoprene Production source category
cancer incidence after the proposed controls in section III.B.2 to
reduce risks to an acceptable level is due to chloroprene emissions
from equipment leaks. Also, of the 48,000 people with cancer risks
greater than or equal to 1-in-1 million after the proposed controls to
reduce risks to an acceptable level, approximately 16,000 people (or 34
percent of the total) have risks greater than or equal to 1-in-1
million due to chloroprene emissions from equipment leaks. Therefore, a
10-20 percent reduction in equipment leak emissions would reduce the
cancer incidence by approximately 1 to 4 percent and the number of
people with cancer risks greater than or equal to 1-in-1 million by
approximately 2,000 to 3,000 people (3 to 7 percent of the total).
However, as described in sections III.C and III.D, the options we
evaluated for equipment leaks are not cost-effective.
In summary, based on our ample margin of safety analysis, we
propose that controls to reduce EtO emissions at HON processes and
chloroprene emissions at neoprene production processes to get risks to
an acceptable level would also provide an ample margin of safety to
protect public health. We also note the proposed changes to the flare
requirements, proposed standards for dioxins/furans, and proposed
standards to remove SSM exemptions (or provide alternative standards in
limited instances) that are in this proposed action and that we are
proposing under CAA sections 112(d)(2) and (3) will achieve additional
reductions in emissions and further strengthen our conclusions that the
standards continue to provide an ample margin of safety to protect
public health for the SOCMI and Neoprene Production source categories.
5. Adverse Environmental Effects
Based on our screening assessment of environmental risk presented
in section III.A.4 of this preamble, we did not identify any areas of
concern with respect to environmental risk. Therefore, we have
determined that HAP emissions from the source categories do not result
in an adverse environmental effect, and we are proposing 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.
C. What are the results and proposed decisions based on our CAA section
112(d)(6) technology review and CAA section 111(b)(1)(B) NSPS reviews,
and what are the rationale for those decisions?
In addition to the proposed EtO- and chloroprene-specific
requirements discussed in section III.B.2 of this preamble, under CAA
section 112(d)(6) we also evaluated developments in practices,
processes, and control technologies for heat exchange systems, storage
vessels, process vents, transfer racks, wastewater, and equipment leaks
for processes subject to the HON, P&R I, and P&R II (see sections
III.C.1 through III.C.6 of this preamble, respectively). Under CAA
section 111(b)(1)(B), for the review of NSPS subpart VVa, we evaluated
BSER for equipment leaks (see section III.C.6.b of this preamble); and
for the review of NSPS subparts III, NNN, and RRR we evaluated BSER for
process vents associated with air oxidation units, distillation
operations, and reactor processes, respectively (see section III.C.3.b
of this preamble). We analyzed costs and emissions reductions for each
emission source (e.g., process vents) by each rule. For NSPS, we
determined cost-effectiveness, cost per ton of emissions reduced, on a
VOC basis. For NESHAP, we determined cost-effectiveness on a HAP basis
from the VOC emissions. We also evaluated fenceline monitoring as a
development in practices considered under CAA section 112(d)(6) for the
purposes of managing fugitive emissions from sources subject to the HON
and P&R I (see section III.C.7 of this preamble).
1. Standards for Heat Exchange Systems
Heat exchangers are devices or collections of devices used to
transfer heat from process fluids to another process fluid (typically
water) without intentional direct contact of the process fluid with the
cooling fluid (i.e., non-contact heat exchanger). There are two types
of heat exchange systems: Closed-loop recirculation systems and once-
through systems. Closed-loop recirculation systems use a cooling tower
to cool the heated water leaving the heat exchanger and then return the
newly cooled water to the heat exchanger for reuse. Once-through
systems typically use surface freshwater (e.g., from rivers) as the
influent cooling fluid to the heat exchangers, and the heated water
leaving the heat exchangers is then discharged from the facility. At
times, the internal tubing material of a heat exchanger can corrode or
crack, allowing some process fluids to mix or become entrained with the
cooling water. Pollutants in the process fluids may subsequently be
released from the cooling water into the atmosphere when the water is
exposed to air (e.g., in a cooling tower for closed-loop systems or
trenches/ponds in a once-through system). The term ``heat exchange
system'' is defined in HON and P&R I at 40 CFR 63.101 and 40 CFR 63.482
(which references 40 CFR 63.101) as 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.
However, the HON and P&R I do not describe a heat exchanger, closed-
loop recirculation system, or once-through cooling system as part of
its definition of ``heat exchange system''. Therefore, we are proposing
to revise the definition of ``heat exchange system'' at 40 CFR 63.101
and 40 CFR 63.482 (which references 40 CFR 63.101) to mean 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). This is
consistent with the definition of ``heat exchange system'' used in the
MON. We are also
[[Page 25124]]
proposing (as is done in the MON) to make clear in this definition
that: (1) For closed-loop recirculation systems, the heat exchange
system consists of a cooling tower, all CMPU heat exchangers that are
in organic HAP service (for HON) or all EPPU heat exchangers that are
in organic HAP service (for P&R I), serviced by that cooling tower, and
all water lines to and from these process unit heat exchangers.; (2)
for once-through systems, the heat exchange system consists of all heat
exchangers that are in organic HAP service, servicing an individual
CMPU (for HON) or EPPU (for P&R I) and all water lines to and from
these heat exchangers; (3) sample coolers or pump seal coolers are not
considered heat exchangers for the purpose of this proposed definition
and are not part of the heat exchange system; and (4) intentional
direct contact with process fluids results in the formation of a
wastewater. This proposed definition would also apply to heat exchange
systems in ethylene oxide service as described in section III.B.2.iii
of this preamble.
The HON and P&R I include an LDAR program for owners or operators
of certain heat exchange systems which meets the requirements of 40 CFR
63.104 (National Emission Standards for Organic Hazardous Air
Pollutants from the Synthetic Organic Chemical Manufacturing Industry).
The LDAR program specifies that heat exchange systems be monitored for
leaks of process fluids into cooling water and that owners or operators
take actions to repair detected leaks within 45 days. Owners or
operators may delay the repair of leaks if they meet the applicable
criteria in 40 CFR 63.104. The current HON and P&R I MACT standards for
heat exchange systems allow the use of any method listed in 40 CFR part
136 to be used to sample cooling water for leaks for the HAP listed in
Table 4 to subpart F (for HON) or Table 5 to 40 CFR 63, subpart U (for
P&R I) (recirculating systems) and Table 9 to subpart G (for HON) or
Table 5 to 40 CFR 63, subpart U (for P&R I) (once-through systems) (and
other representative substances such as TOC or VOC that can indicate
the presence of a leak can also be used). A leak in the heat exchange
system is detected if the exit mean concentration of HAP (or other
representative substance) in the cooling water is at least 1 ppmw or 10
percent greater than (using a one-sided statistical procedure at the
0.05 level of significance) the entrance mean concentration of HAP (or
other representative substance) in the cooling water. Furthermore, the
HON and P&R I allow owners or operators to monitor for leaks using a
surrogate indicator of leaks (e.g., ion-specific electrode monitoring,
pH, conductivity), provided that certain criteria in 40 CFR 63.104(c)
are met. The HON and P&R I initially require 6 months of monthly
monitoring for existing heat exchange systems. Thereafter, the
frequency can be reduced to quarterly. The leak monitoring frequencies
are the same whether water sampling and analysis or surrogate
monitoring is used to identify leaks.
Our technology review identified one development in LDAR practices
and processes for heat exchange systems, the use of the Modified El
Paso Method \61\ to monitor for leaks. The Modified El Paso Method,
which is included in the MON, EMACT standards, and the Petroleum
Refinery Sector rule, was identified in our review of the RACT/BACT/
LAER clearinghouse database. It is also required by the Texas
Commission on Environmental Quality (TCEQ) for facilities complying
with their highly reactive volatile organic compound (HRVOC) rule
(i.e., 30 Texas Administrative Code (TAC) Chapter 115, Subchapter H,
Division 3). The Modified El Paso Method measures a larger number of
compounds than the current methods required in the HON and P&R I and is
more effective in identifying leaks. For heat exchange system LDAR
programs, the compliance monitoring option, leak definition, and
frequency of monitoring for leaks are all important considerations
affecting emission reductions by identifying when there is a leak and
when to take corrective actions to repair the leak. Therefore, we
evaluated the Modified El Paso Method for use at HON and P&R I
facilities, including an assessment of appropriate leak definitions and
monitoring frequencies.
---------------------------------------------------------------------------
\61\ 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
(FID) 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.
---------------------------------------------------------------------------
In order to identify an appropriate Modified El Paso Method leak
definition for HON-subject facilities, we identified four rules, TCEQ's
HRVOC rule, the MON, the EMACT standards, and the Petroleum Refinery
Sector rule, all of which incorporate this monitoring method and have
leak definitions corresponding to the use of this methodology. We also
reviewed data submitted in response to a CAA section 114 request for
the Ethylene Production RTR where facilities performed sampling using
the Modified El Paso Method.
The TCEQ's HRVOC rule, the MON, the EMACT standards, and the
Petroleum Refinery Sector rule have leak definitions of total
strippable hydrocarbon concentration (as methane) in the stripping gas
ranging from 3.1 ppmv to 6.2 ppmv. In addition, sources subject to the
MON, the EMACT standards, or the Petroleum Refinery Sector rule may not
delay the repair of leaks for more than 30 days where, during
subsequent monitoring, a total strippable hydrocarbon concentration (as
methane) in the stripping gas of 62 ppmv or higher is found. In
reviewing the Ethylene Production RTR CAA section 114 data, a clear
delineation in the hydrocarbon mass emissions data was noticed at 6.1
ppmv of total strippable hydrocarbon (as methane) in the stripping gas.
In addition, given that both the leak concentration and water
recirculation rate of the heat exchange system are key variables
affecting the hydrocarbon mass emissions from heat exchange systems,
the overall Ethylene Production RTR CAA section 114 data for all heat
exchange systems sampled generally showed lower hydrocarbon mass
emissions for leaks at or below 6.1 ppmv of total strippable
hydrocarbon (as methane) in the stripping gas compared to leaks found
above 6.1 ppmv of total strippable hydrocarbon (as methane) in the
stripping gas. Taking into account the range of actionable leak
definitions in use by other rules that require use of the Modified El
Paso Method currently (i.e., 3.1 ppmv-6.2 ppmv of total strippable
hydrocarbon (as methane) in the stripping gas), and the magnitude of
emissions for leaks as a result of total strippable hydrocarbon (as
methane) in the stripping gas above 6.1 ppmv compared to leaks
identified in the CAA section 114 sampling data as a result of other
actionable leak definitions, we chose to evaluate a leak definition at
the upper end of identified actionable leak definitions in our
analysis. Thus, the Modified El Paso Method leak definition we
evaluated was 6.2 ppmv of total strippable hydrocarbon concentration
(as methane) in the stripping gas for both new and existing heat
exchange systems, along with not allowing delay of repair of leaks for
more than 30 days where, during subsequent monitoring, a total
strippable hydrocarbon concentration (as methane) in the stripping gas
of 62 ppmv or higher is found.
We determined an appropriate leak monitoring frequency by reviewing
the
[[Page 25125]]
current monitoring frequencies that HON and P&R I facilities are
subject to, along with frequencies for the TCEQ's HRVOC rule, the MON,
the EMACT standards, and the Petroleum Refinery Sector rule, and
information gathered in the Ethylene Production RTR CAA section 114
survey. As a first step, we reviewed whether it was still reasonable to
specify more frequent monitoring for a 6-month period after repair of
leaks. Our review of the Ethylene Production RTR CAA section 114 data
showed that no leaks were identified during the 6-month period post
repair for any of the facilities that reported leak emissions in their
heat exchange system compliance data. Thus, we find that re-monitoring
once after repair of a leak, at the monitoring location where the leak
was identified, is sufficient from a continuous compliance perspective
to demonstrate a successful repair. The monitoring frequencies
currently required by the HON and P&R I when no leaks are found were,
thus, considered the base frequencies (i.e., quarterly monitoring for
existing and new heat exchange systems). Once we determined the base
frequencies, we next considered more stringent monitoring frequencies.
Both the Petroleum Refinery Sector rule, which includes monthly
monitoring for existing sources, under certain circumstances, and the
TCEQ HRVOC rule, which includes continuous monitoring provisions for
existing and new sources, have more stringent monitoring frequencies.
However, the incremental HAP cost effectiveness to change from
quarterly to monthly monitoring and monthly to continuous monitoring
was found to be $40,000/ton and $500,000/ton, respectively. We conclude
that these costs are not reasonable for HON and P&R I facilities. Thus,
we chose to evaluate quarterly monitoring for existing and new heat
exchange systems (i.e., the base monitoring frequency currently in the
rule).
Based on this technology review, we identified the following
control option for heat exchanger systems as a development in practice
that can be implemented at a reasonable cost: Quarterly monitoring for
existing and new heat exchange systems (after an initial 6 months of
monthly monitoring) with 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 then estimated the impacts of this control option assuming that
all 207 HON facilities and 19 P&R I facilities (10 of which are
collocated with HON facilities) would be affected by requiring the use
of the Modified El Paso Method. As part of our analysis, we assumed
owners or operators conducting quarterly monitoring for three or more
of these heat exchange systems would elect to purchase a stripping
column and FID analyzer and perform in-house Modified El Paso
monitoring (because the total annualized costs for in-house Modified El
Paso monitoring are less than the costs for contracted services). In
addition, we assumed repairs could be performed by plugging a specific
heat exchanger tube, and if a heat exchanger is leaking to the extent
that it needs to be replaced, then it is effectively at the end of its
useful life. Therefore, we determined that the cost of replacing a heat
exchanger is an operational cost that would be incurred by the facility
as a result of routine maintenance and equipment replacement, and it is
not attributable to the control option.
Table 10 of this preamble presents the nationwide impacts for
requiring owners or operators at HON facilities (including 10 P&R I
facilities collocated with HON facilities) 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. Table 11 of
this preamble presents the nationwide impacts for requiring owners or
operators at P&R I facilities (not collocated with HON facilities) 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. See 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, which is available in the docket for this
rulemaking, for details on the assumptions and methodologies used in
this analysis.
Based on the costs and emission reductions for the identified
control option, we are proposing to revise the HON and P&R I for heat
exchange systems pursuant to CAA section 112(d)(6). We are proposing at
40 CFR 63.104(g)(4) \62\ to specify 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. Owners and operators would be required to repair the
leak to reduce the concentration or mass emissions rate to below the
leak action level as soon as practicable, but no later than 45 days
after identifying the leak. We are also proposing 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). This
would apply to both monitoring heat exchange systems and individual
heat exchangers by replacing the use of any 40 CFR part 136 water
sampling method with the Modified El Paso Method and removing the
option that allows for use of a surrogate indicator of leaks. We are
also proposing at 40 CFR 63.104(h) and (i) that repair include re-
monitoring at the monitoring location where a leak is identified to
ensure that any leaks found are fixed. We are proposing that none of
these proposed requirements would apply to heat exchange systems that
have a maximum cooling water flow rate of 10 gallons per minute or less
because owners and operators of smaller heat exchange systems would be
disproportionally affected and forced to repair leaks with a much lower
potential HAP emissions rate than owners and operators of heat exchange
systems with larger recirculation rate systems. Finally, we are
proposing at 40 CFR 63.104(l) that the leak monitoring requirements for
heat exchange systems at 40 CFR 63.104(b) may be used in limited
instances, instead of using the Modified El Paso Method to monitor for
leaks. We still maintain that the Modified El Paso Method is the
preferred method to monitor for leaks in heat exchange systems and are
proposing that the requirements of 40 CFR 63.104(b) may only be used if
99 percent by weight or more of all the organic compounds that could
potentially leak into the cooling water have a Henry's Law Constant
less than 5.0E-6 atmospheres per mole per cubic meter (atm-m\3\/mol) at
25[deg] Celsius. We selected this threshold based on a review of
Henry's Law Constants for the HAP listed in Table 4 to subpart F of 40
[[Page 25126]]
CFR part 63, as well as the water-soluble organic compounds listed in a
recent alternative monitoring request from a MON facility.\63\ Henry's
Law Constants are available from the EPA at https://comptox.epa.gov/dashboard/. Examples of HAP that have a Henry's Law Constant of less
than 5.0E-6 atm-m\3\/mol at 25[deg] Celsius are aniline, 2-
chloroacetophenone, diethylene glycol diethyl ether, diethylene glycol
dimethyl ether, dimethyl sulfate, 2,4-dinitrotoluene, 1,4-dioxane,
ethylene glycol monoethyl ether acetate, ethylene glycol monomethyl
ether acetate, methanol, and toluidine. Many of these HAP also have
very high boiling points, with most above 300 Fahrenheit, which means
they will generally stay in the cooling water and not be emitted to the
atmosphere. We solicit comment on all of the proposed requirements
related to heat exchange systems.
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\62\ We note that each of the HON citations mentioned in this
paragraph of this preamble are also applicable to P&R I facilities
pursuant to 40 CFR 63.502(n). In order for these proposed HON
citations to properly apply to P&R I facilities, we are proposing
substitution rule text at 40 CFR 63.502(n)(7).
\63\ In May 2021, EPA Region 4 received a request from Eastman
Chemical Company to perform alternative monitoring instead of the
Modified El Paso Method to monitor for leaks in Eastman's Tennessee
Operations heat exchange systems, which primarily have cooling water
containing soluble HAP with a high boiling point. Eastman
specifically identified two HAP, 1,4-dioxane and methanol, which do
not readily strip out of water using the Modified El Paso Method.
Eastman's application for alternative monitoring included
experimental data showing that the Modified El Paso Method would
likely not identify a leak of these HAP in heat exchange system
cooling water. Eastman conducted Modified El Paso Method monitoring
under controlled scenarios to determine how much methanol and 1,4-
dioxane would be detected. The scenarios included solutions of water
and either methanol or 1,4-dioxane at concentrations of 1 part per
million by weight (ppmw), 20 ppmw, and 100 ppmw (as measured using
water sampling methods allowed previously in the MON). The Modified
El Paso Method did not detect any methanol or 1,4-dioxane from the 1
ppmw and 20 ppmw solutions (i.e., methanol and 1,4-dioxane did not
strip out of the water in detectable amounts). The Modified El Paso
Method detected very little HAP from the 100 ppmw solutions, with a
maximum of only 0.17 percent of the 1,4-dioxane stripping out and
being detected.
Table 10--Nationwide Emissions Reductions and Cost Impact for Requiring the Modified El Paso Method for Heat Exchange Systems at HON Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total
Total VOC emission HAP emission HAP cost annualized HAP cost
Control option Total capital annualized table reductions effectiveness costs with effectiveness
investment ($) costs w/o reductions (tpy) w/o recovery recovery with recovery
credits ($/yr) (tpy) credits ($/ton) credits ($/yr) credits ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1................................ 770,000 228,000 934 93 2,440 (612,700) (6,560)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 11--Nationwide Emissions Reductions and Cost Impact for Requiring the Modified El Paso Method for Heat Exchange Systems at P&R I Facilities
[Not collocated with HON facilities]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total
Total VOC emission HAP emission HAP cost annualized HAP cost
Control option Total capital annualized reductions reductions effectiveness w/ costs with effectiveness
investment ($) costs w/o (tpy) (tpy) o recovery recovery with recovery
credits ($/yr) credits ($/ton) credits ($/yr) credits ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1................................ 48,300 9,900 33 3 3,050 (19,320) (5,940)
--------------------------------------------------------------------------------------------------------------------------------------------------------
2. Standards for Storage Vessels
Storage vessels are used to store liquid and gaseous feedstocks for
use in a process, as well as to store liquid and gaseous products from
a process. Most HON, P&R I, and P&R II storage vessels are designed for
operation at atmospheric or near atmospheric pressures; pressure
vessels are used to store compressed gases and liquefied gases.
Atmospheric storage vessels are typically cylindrical with a vertical
orientation, and they are constructed with either a fixed roof or a
floating roof. Some, generally small, atmospheric storage vessels are
oriented horizontally. Pressure vessels are either spherical or
horizontal cylinders.
The HON requires owners and operators control emissions from
storage vessels with capacities between 75 m\3\ and 151 m\3\ and a MTVP
greater than or equal to 13.1 kPa, and storage vessels with capacities
greater than or equal to 151 m\3\ and a MTVP greater than or equal to
5.2 kPa. Storage vessels meeting this criteria are considered Group 1
storage vessels. Owners and operators of HON Group 1 storage vessels
storing a liquid with a MTVP of total organic HAP less than 76.6 kPa
are required to reduce emissions of organic HAP by 95 percent (or 90
percent if the storage vessel was installed on or before December 31,
1992) 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.
Owners and operators of HON Group 1 storage vessels storing a liquid
with a MTVP of total organic HAP greater than or equal to 76.6 kPa are
required to reduce emissions of organic HAP by 95 percent (or 90
percent if the storage vessel was installed on or before December 31,
1992) utilizing a closed vent system and control device, or reduce
organic HAP emissions by routing the emissions to a process or a fuel
gas system, or vapor balancing. In general, HON storage vessels that do
not meet the MTVP and capacity thresholds described above are
considered Group 2 storage vessels and are not required to apply any
additional emission controls provided they remain under 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. Generally, the
P&R I standards for storage vessels refer to the provisions in the HON.
As such, owners and operators of Group 1 storage vessels subject to P&R
I are required to control these vessels as prescribed in the HON.
The P&R II standards for storage tanks (P&R II uses the term
``storage tank'' in lieu of ``storage vessel'' like the HON and P&R I)
do not specify any sort of stratification into groups. P&R II defines
``storage tank'' to mean tank or other vessel that is used to store
liquids that contain one or more HAP compounds.
[[Page 25127]]
As previously mentioned, 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) standard
for existing sources in both BLR (130 pounds) and WSR (10 pounds). For
new sources, BLR requires 98 percent reduction or an overall limit of
5,000 pounds of HAP per year. New WSR sources are limited to 7 pounds
of HAP per million pounds WSR produced.
As part of our technology review for HON and P&R I storage vessels,
we identified the following emission reduction options: (1) Revising
the capacity and MTVP thresholds of the HON and P&R I 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 kPa 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; (2) in
addition to requirements specified in option 1, requiring upgraded deck
fittings \64\ and controls for guidepoles for all storage vessels
equipped with an IFR as already required in 40 CR 63, subpart WW; and
(3) in addition to requirements specified in options 1 and 2, requiring
the conversion of EFRs to IFRs through use of geodesic domes. We did
not identify any control options for storage tanks subject to P&R II.
---------------------------------------------------------------------------
\64\ Require 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 the deck cover
would be required to be equipped with a gasket between the cover and
the deck.
---------------------------------------------------------------------------
We identified option 1 as a technologically feasible development in
practices, processes, and control technologies for storage vessels used
at HON and P&R I facilities because it reflects requirements for
similar storage vessels that are located at chemical manufacturing
facilities subject to the MON. Option 2 is an improvement in practices
because these upgraded deck fittings and guidepole controls have been
required by other regulatory agencies and other EPA regulatory action
(e.g., Petroleum Refinery Sector rulemaking) since promulgation of the
HON and P&R I and are being used by some of the sources covered by the
SOCMI source category. Finally, we consider option 3 to be a
development in control technology because we found that some storage
vessels with EFRs have installed geodesic domes since promulgation of
the HON and P&R I.
We used information about storage vessel capacity, design, and
stored materials that industry provided to the EPA in response to our
CAA section 114 request (see section II.C of this preamble) to evaluate
the impacts of all three of the options presented. We identified eight
HON storage vessels and two P&R I storage vessels from our CAA section
114 request that would be impacted by option 1; extrapolating this data
to all 207 HON facilities and 19 P&R I facilities (10 of which are
collocated with HON facilities), we estimated costs and emissions
reductions for 63 HON storage vessels and 4 P&R I storage vessels that
would be impacted by option 1. This same distribution would apply to
option 2. For option 3, we identified five HON EFR storage vessels and
zero P&R I EFR storage vessels from our CAA section 114 request that
would be impacted; extrapolating this data to all 207 HON facilities
and 19 P&R I facilities (10 of which are collocated with HON
facilities) we estimated costs and emissions reductions for 159 HON EFR
storage vessels and 5 P&R I EFR storage vessels \65\ that would be
impacted by option 3.
---------------------------------------------------------------------------
\65\ Although no EFR tanks were reported for P&R I as part of
our CAA section 114 request, we assumed five P&R I EFR storage
vessels based on the number of HON average EFR storage vessels per
HON CMPU that were reported.
---------------------------------------------------------------------------
Table 12 of this preamble presents the nationwide impacts for the
three options considered for HON facilities (including 10 P&R I
facilities collocated with HON facilities). Table 13 of this preamble
presents the nationwide impacts for the three options considered for
P&R I facilities (not collocated with HON facilities). See 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, which is available in the docket for this rulemaking, for
details on the assumptions and methodologies used in this analysis,
including the calculations we used to account for additional HON and
P&R I facilities that did not receive a CAA section 114 request.
We determined that option 2 (which includes option 1) is cost
effective and we are proposing, pursuant to CAA section 112(d)(6), to
revise the Group 1 storage capacity criterion (for HON and P&R I
storage vessels at existing sources) from between 75 m\3\ and 151 m\3\
to between 38 m\3\ and 151 m\3\ (see proposed Table 5 to subpart G),
and require upgraded deck fittings and controls for guidepoles for all
storage vessels equipped with an IFR as already required in 40 CR 63,
subpart WW (see proposed 40 CFR 63.119(b)(5)(ix), (x), (xi), and
(xii)). Considering the emissions reductions and high incremental cost
effectiveness, we determined that storage vessel option 3 is not cost
effective and are not proposing to revise the HON and P&R I to reflect
the requirements of this option pursuant to CAA section 112(d)(6). We
solicit comment on the proposed revisions for storage vessels.
Table 12--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for Storage Vessels at HON Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
HAP incremental
Total VOC emission HAP emission HAP cost cost
Control option Total capital annualized reductions reductions effectiveness effectiveness
investment ($) costs ($/yr) (tpy) (tpy) ($/ton) (from Option 1)
($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.................................................... 1,727,000 327,400 58.0 40.6 8,070 .................
2.................................................... 2,191,500 415,500 68.2 47.7 8,710 12,400
3.................................................... 28,916,200 4,065,700 84.3 59.0 68,880 N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 25128]]
Table 13--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for Storage Vessels at P&R I Facilities
[Not collocated with HON facilities]
--------------------------------------------------------------------------------------------------------------------------------------------------------
HAP incremental
Total VOC emission HAP emission HAP cost cost
Control option Total capital annualized reductions reductions effectiveness effectiveness
investment ($) costs ($/yr) (tpy) (tpy) ($/ton) (from Option 1)
($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.................................................... 109,000 20,700 3.7 2.6 7,960 .................
2.................................................... 131,000 24,800 4.1 2.9 8,550 13,700
3.................................................... 912,200 128,300 2.7 1.9 67,500 N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
3. Standards for Process Vents
A process vent is a gas stream that is discharged during the
operation of a particular unit operation (e.g., separation processes,
purification processes, mixing processes, reaction processes). The gas
stream(s) may be routed to other unit operations for additional
processing (e.g., a gas stream from a reactor that is routed to a
distillation column for separation of products), sent to one or more
recovery devices, sent to a process vent header collection system
(e.g., blowdown system) and APCD (e.g., flare, thermal oxidizer, carbon
adsorber), and/or vented to the atmosphere. Process vents may be
generated from continuous and/or batch operations,\66\ as well as from
other intermittent types of operations (e.g., maintenance operations).
If process vents are required to be controlled prior to discharge to
the atmosphere to meet an applicable emissions standard, then they are
typically collected and routed to an APCD through a closed vent system.
---------------------------------------------------------------------------
\66\ P&R I and P&R II regulate process vents from both
continuous and batch operations. The HON and NSPS subparts III, NNN,
and RRR only regulate process vents if some, or all, of the gas
stream originates as a continuous flow.
---------------------------------------------------------------------------
NSPS subparts III, NNN, and RRR regulate gas streams from air
oxidation reactors, distillation columns, and other reactor processes,
respectively. Importantly, the NSPS subparts III, NNN, and RRR formed
the basis for the HON process vent MACT standards in that to be
considered a HON process vent, some or all of the gas stream must
originate as a continuous flow from an air oxidation reactor,
distillation unit, or other reactor process during operation of a CMPU.
P&R I regulates batch front-end process vents, continuous front-end
process vents, and aggregate batch vent streams from condensers,
distillation units, reactors, or other unit operations within an EPPU.
Generally, process vents subject to NSPS subparts III, NNN, or RRR, or
the HON and/or P&R I are grouped based on the flow rate, HAP
concentration, and a TRE index value.\67\ P&R II defines a process vent
as a point of emission from a unit operation, such as condenser vents,
vacuum pumps, steam ejectors and atmospheric vents from reactors and
other process vessels; and no further stratification into groups for
applicability is specified.
---------------------------------------------------------------------------
\67\ TRE is discussed in more detail below in section III.C.3.a
of this preamble (for NESHAP) and section III.C.3.b of this preamble
(for NSPS).
---------------------------------------------------------------------------
The results of our CAA section 112(d)(6) technology review for
process vents associated with HON, P&R I, and P&R II processes are
discussed in section III.C.3.a of this preamble. The results of our CAA
111(b)(1)(B) review for process vents subject to NSPS subparts III,
NNN, or RRR are discussed in section III.C.3.b of this preamble.
a. HON, P&R I, and P&R II
As previously mentioned, the HON standards divide process vents
into Group 1 process vents, which require controls, and Group 2 process
vents, which generally do not require controls provided they remain
below Group 1 thresholds. A Group 1 HON process vent is a process vent
for which the vent stream flow rate is greater than or equal to 0.005
scmm, the total organic HAP concentration is greater than or equal to
50 ppmv, and the TRE index value is less than or equal to 1.0
(according to the determination procedures at 40 CFR 63.115). The TRE
index value is a measure of the supplemental total resource requirement
per unit VOC (or HAP) reduction. It takes into account all the
resources which are expected to be used in VOC (or HAP) control by
thermal oxidation and provides a dimensionless measure of resource
burden based on cost effectiveness. Resources include supplemental
natural gas, labor, and electricity. Additionally, if the off-gas
contains halogenated compounds, resources will also include caustic and
scrubbing and quench makeup water. For the HON and P&R I, the TRE index
value is derived from the cost effectiveness associated with HAP
control by a flare or thermal oxidation, and is a function of vent
stream flowrate, vent stream net heating value, hourly emissions, and a
set of coefficients. The TRE index value was first introduced in an EPA
document titled: Guideline Series for Control of Volatile Organic
Compound (VOC) Emissions from Air Oxidation Processes in Synthetic
Organic Chemical Manufacturing Industry (SOCMI) (see EPA-450/3-84-015,
December 1984). The EPA incorporated the TRE concept into the original
HON (see 59 FR 19468, April 22, 1994) and the original P&R I rulemaking
(see 61 FR 46906, September 5, 1996). The TRE index value is used in 40
CFR 63 subpart G and 40 CFR 63 subpart U as an alternative mode of
compliance for process vent regulations. The TRE index value can also
trigger monitoring, recordkeeping, and reporting requirements. In
general, as previously mentioned for the HON and P&R I, continuous
process vents with a TRE index value equal to or less than 1.0 are
required to be controlled. For additional details regarding the TRE
index value (including the equation and coefficients used to calculate
the TRE index value for the HON and P&R I), 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, which is available in the docket
for this rulemaking.
The HON standards require uncontrolled Group 1 process vents to
reduce total organic HAP \68\ emissions by 98 percent by weight by
venting emissions through a closed vent system to any combination of
control devices or by venting emissions through a closed
[[Page 25129]]
vent system to a flare.\69\ The P&R I standards for continuous front-
end process vents use the same Group 1 flow rate, HAP concentration,
and TRE index value threshold criterion as the HON; refer to the same
provisions in the HON for group determination (i.e., owners and
operators of continuous front-end process vents subject to P&R I
determine whether control is required based on the flow rate, HAP
concentration, and TRE index value using the same HON determination
procedures at 40 CFR 63.115); and require the same level as control as
the HON (i.e., reduce total organic HAP \70\ emissions by 98 percent by
weight by venting emissions through a closed vent system to any
combination of control devices or by venting emissions through a closed
vent system to a flare).\71\
---------------------------------------------------------------------------
\68\ For HON, organic HAP refers to chemicals listed in Table 2
to NESHAP subpart F.
\69\ See also, footnote 16, for halogenated vent streams that
are Group 1.
\70\ For P&R I, organic HAP refers to chemicals listed in Table
5 to NESHAP subpart U.
\71\ See also, footnote 16, for halogenated vent streams that
are Group 1.
---------------------------------------------------------------------------
The P&R I standards do not refer to the HON for batch front-end
process vents. The P&R I group determination for batch front-end vents
is based on annual HAP emissions and annual average batch vent flow
rate. Group 1 batch front-end process vent means a batch front-end
process vent releasing annual organic HAP emissions greater than or
equal to 11,800 kg/yr (26,014 lb/yr) and with a cutoff flow rate
greater than or equal to the annual average batch vent flow rate.\72\
The cutoff flow rate is calculated in accordance with 40 CFR 63.488(f).
Annual organic HAP emissions and annual average batch vent flow rate
are determined at the exit of the batch unit operation, as described in
40 CFR 63.488(a)(2). Annual organic HAP emissions are determined as
specified in 40 CFR 63.488(b), and annual average batch vent flow rate
is determined as specified in 40 CFR 63.488(e).
---------------------------------------------------------------------------
\72\ P&R I also contains standards for halogenated batch process
vents.
---------------------------------------------------------------------------
The P&R II standards for process vents do not specify any sort of
stratification into groups. However, the rule does have different
performance testing requirements depending on whether the process vent
is part of a continuous process \73\ or if flow of gaseous emissions is
intermittent. As previously mentioned, 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) standard for existing sources in both BLR (130 pounds)
and WSR (10 pounds). For new sources, BLR requires 98 percent reduction
or an overall limit of 5,000 pounds of HAP per year. New WSR sources
are limited to 7 pounds of HAP per million pounds WSR produced.
---------------------------------------------------------------------------
\73\ P&R II defines ``continuous process'' to mean a process
where the inputs and outputs flow continuously throughout the
duration of the process. Continuous processes are typically steady-
state.
---------------------------------------------------------------------------
As part of our technology review for HON and P&R I continuous
process vents, we identified the following emission reduction options:
(1) Remove the TRE concept in its entirety, remove the 50 ppmv and
0.005 scmm Group 1 process vent thresholds, and redefine a HON Group 1
process vent and P&R I Group 1 continuous front-end process vent
(require control) as any process vent that emits greater than or equal
to 1.0 lb/hr of total organic HAP; (2) the same requirements specified
in option 1, but redefine a HON Group 1 process vent and P&R I Group 1
continuous front-end process vent (require control) as any process vent
that emits greater than or equal to 0.10 lb/hr of total organic HAP;
and (3) keep the TRE concept and keep the 50 ppmv and 0.005 scmm Group
1 process vent thresholds, but change the TRE index value threshold
from 1.0 to 5.0. We did not identify any control options for P&R II
process vents.
We identified options 1 and 2 as developments in practices,
processes, and control technologies for multiple reasons. First, we
identified at least one 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. Second, based
on the responses to our CAA section 114 request, we observed that some
facilities are voluntarily controlling continuous process vents that
are not required by the HON and P&R I to be controlled per the results
of the TRE index value calculation. Of the 13 HON facilities that
received the CAA section 114 request, at least three facilities
confirmed they were voluntarily controlling some of their Group 2
process vents. We expect other HON and P&R I facilities will do this
too because some facilities stated in their response to the CAA section
114 request that, pursuant to 40 CFR 63.113(h), many of their process
vents are voluntarily designated as Group 1 process vents ``so that TRE
calculations are not required.'' In other words, some facilities are
likely electing to control certain process vents that have TRE index
values greater than 1.0. Third, based on the responses to our CAA
section 114 request, we observed that facilities are routing multiple
continuous process vents to a single APCD. This is significant because
the current use of the TRE index value is only based on controlling a
single process vent with a single APCD, an unrealistic scenario when
compared to how chemical manufacturing facilities actually control
their process vents. It is much more likely that a facility routes
numerous process vents to the same APCD. Finally, also based on
responses to our CAA section 114 request, one facility provided over
300 pages of modeled runs that were used to help the facility determine
certain characteristics of their continuous HON and P&R I process vents
for inputs to TRE index value calculations. The facility had originally
included these modeled runs with their Notification of Compliance
Status report; we reviewed this information and concluded that
determining a TRE index value for certain process vent streams is often
theoretical, can be extremely complicated, and is uncertain. In
addition, because the TRE index value is largely a theoretical
characterization tool, it can be very difficult to enforce. In order to
calculate a TRE index value, owners and operators must determine
numerous input values; and without the correct amount of process
knowledge, verifying inputs can be problematic.
We identified option 3 as a development in practices, processes,
and control technologies because we determined that another chemical
manufacturing NESHAP (i.e., the MON) contains a TRE index value
threshold criteria (i.e., less than or equal to 1.9) that is more
stringent than the HON and P&R I TRE index value threshold criteria
(i.e., less than or equal to 1.0). Additionally, we identified one
particular state rule that uses a more stringent TRE index value
threshold than the HON and P&R I TRE index value threshold
criteria.\74\ This state rule requires owners and operators of air
oxidation processes to control any process vent stream or combination
of process vent streams with a TRE index value less than or equal to
6.0.\75\
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\74\ See Illinois Title 35: Subtitle B: Chapter I: Subchapter C:
Parts 218 and 219 (i.e., Organic Material Emission Standards And
Limitations For The Chicago Area Subpart V: Batch Operations And Air
Oxidation Processes; and Organic Material Emission Standards And
Limitations For The Metro East Area Subpart V: Batch Operations And
Air Oxidation Processes).
\75\ Although the TRE equation for Illinois Title 35: Subtitle
B: Chapter I: Subchapter C: Parts 218 and 219 has a different set of
TRE coefficients than that of the HON and P&R I, we examined
multiple scenarios and determined that a process vent not required
to be controlled by the HON or P&R I could still be required to be
controlled by this Illinois rule. For example, a halogenated process
vent with a net heating value of 100 MJ/scm, a flowrate of 0.82 scm/
min, a TOC mass flow rate of 9 kg/hr, and a HAP mass flow rate of 1
kg/hr would yield a TRE of 3.87 using the HON and/or the P&R I TRE
equation (and 3.87 is above the HON and P&R I index value thresholds
of 1.0 so no control would be required); however, this same stream
would yield a TRE of 5.28 using the Illinois rule TRE equation (and
5.28 is below the Illinois rule TRE index value threshold of 6.0, so
control is required).
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[[Page 25130]]
To evaluate impacts of all three of the options presented, we used
information from about 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. Using vent stream flowrates, vent stream net heating values,
and 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,\76\ we first calculated a cost
effectiveness 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). Using this subset
of Group 2 continuous process vents, we extrapolated a set of
distributions and parameters that we could apply to all 207 HON
facilities and 19 P&R I facilities in order to evaluate impacts of all
three of the options presented for continuous HON and P&R I process
vents, noting that six of the 23 Group 2 continuous process vents are
already voluntarily controlled even though the HON and P&R I do not
require them to be. For Group 2 continuous process vents already
voluntarily being controlled, we assumed owners and operators use
existing APCDs. For Group 2 process vents not already being voluntarily
controlled, we assumed owners and operators would need to install an
APCD; therefore, we estimated costs to install a thermal oxidizer using
the EPA's control cost template.\77\ We estimated that 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 nine are not currently
controlled) would be impacted by option 1 (i.e., control process vents
with a total organic HAP emission rate greater than 1.0 lb/hr). For
option 2 (i.e., control process vents with a total organic HAP emission
rate greater than 0.10 lb/hr), 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. For option 3 (i.e., control process vents with a TRE index
value less than or equal to 5.0), we estimated that 16 HON facilities
operating 64 HON Group 2 process vents (32 of which are already
voluntarily controlled and 32 that are not currently controlled) and 3
P&R I facilities operating nine P&R II Group 2 continuous front-end
process vents (in which all 9 are not currently controlled) would be
impacted.
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\76\ EPA, 2002. EPA Control Cost Manual, Sixth Edition. January
2002. Publication Number EPA/452/B-02-001.
\77\ Refer to the file ``Incinerators and Oxidizers Calculation
Spreadsheet (note: updated on 1/16/2018) (xlsm)'' which follows the
methodology from the sixth edition of the EPA Air Pollution Control
Cost Manual and can be found at the following website: https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution.
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Table 14 of this preamble presents the nationwide impacts for the
three options considered for continuous process vents at HON
facilities. Table 15 of this preamble presents the nationwide impacts
for the three options considered for continuous process vents at P&R I
facilities. We determined that option 1 is cost effective and we are
proposing, pursuant to CAA section 112(d)(6), to remove the TRE concept
in its entirety from the HON and P&R I. We are also proposing, pursuant
to CAA section 112(d)(6), to remove the 50 ppmv and 0.005 scmm Group 1
process vent thresholds from the HON Group 1 process vent definition
and P&R I Group 1 continuous front-end process vent definition, and
instead require owners and operators of HON or P&R I process vents that
emit greater than or equal to 1.0 lb/hr of total organic HAP to reduce
emissions of organic HAP using a flare meeting the proposed operating
and monitoring requirements for flares (see section III.D.1 of this
preamble); or reduce emissions of total organic HAP or TOC by 98
percent by weight or to an exit concentration of 20 ppmv, whichever is
less stringent. We are not proposing to revise the HON and P&R I to
reflect the requirements of process vent options 2 and 3 pursuant to
CAA section 112(d)(6). We determined that process vent option 2 is not
cost effective, and while we believe option 3 is cost effective, it
would require keeping the TRE concept in the rule which for reasons
explained above is not desired. We solicit comment on the proposed
revisions for process vents for the HON and P&R I.
Table 14--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for Continuous Process
Vents at HON Facilities
----------------------------------------------------------------------------------------------------------------
Total VOC emission HAP emission HAP cost
Control option Total capital annualized reductions reductions effectiveness
investment ($) costs ($/yr) (tpy) (tpy) ($/ton)
----------------------------------------------------------------------------------------------------------------
1............................... 1,218,000 3,150,000 436 436 7,200
2............................... 5,732,000 10,329,000 809 533 19,400
3............................... 1,493,000 3,208,000 441 441 7,300
----------------------------------------------------------------------------------------------------------------
[[Page 25131]]
Table 15--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for Continuous Process
Vents at P&R I Facilities
----------------------------------------------------------------------------------------------------------------
Total VOC emission HAP emission HAP cost
Control option Total capital annualized reductions reductions effectiveness
investment ($) costs ($/yr) (tpy) (tpy) ($/ton)
----------------------------------------------------------------------------------------------------------------
1............................... 198,000 586,000 51.0 51.0 11,500
2............................... 557,000 1,242,000 80.1 72.4 17,200
3............................... 215,000 590,000 54.8 54.8 10,800
----------------------------------------------------------------------------------------------------------------
As part of our technology review for P&R I batch front-end process
vents, we identified the following emission reduction option: revise
the P&R I control threshold for batch front-end process vents from
26,014 lb/yr on an individual vent basis to 10,000 lb/yr on an
aggregate vent basis. We identified this option as a development in
practices, processes, and control technologies based on our comparison
of the batch process vent requirements in the NESHAP for Chemical
Manufacturing Area Sources (CMAS) compared to those in P&R I. We note
that CMAS regulates batch process vents from nine area source
categories in the chemical manufacturing sector. Owners and operators
of a CMAS CMPU with collective uncontrolled organic HAP emissions
greater than or equal to 10,000 lb/yr from all batch process vents
associated with an affected CMPU must meet emission limits for organic
HAP emissions. GACT for batch process vents is defined in the CMAS
NESHAP as 85 percent control for existing batch process units (and 90
percent for new units) that have uncontrolled organic HAP emissions
equal to or greater than 10,000 lb/yr. As mentioned in the CMAS NESHAP
rulemaking,\78\ this applicability threshold of 10,000 lb/yr per batch
process was also used in the MON and provides indicia of the size of a
CMPU because the MON applies to major sources of HAP. The EPA used
information from the baseline facility MON database and determined that
costs to meet an 85 percent control requirement for existing CMAS CMPUs
with uncontrolled organic HAP emissions equal to or greater than 10,000
lb/yr were reasonable ($8,700/ton). We also note that, based on a
response to our CAA section 114 request, a facility (the only facility
that received the CAA section 114 request and is subject to P&R I)
reported to the EPA that it is controlling its five batch front-end
process vents even though P&R I does not require these vents to be
controlled.\79\
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\78\ See 74 FR 56008, October 29, 2009.
\79\ As previously mentioned, the P&R I control threshold for
batch front-end process vents is on an individual vent basis; and
each of the batch front-end process vents at this facility releases
annual organic HAP emissions less than 11,800 kg/yr (26,014 lb/yr)
which is below the control threshold of P&R I.
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To evaluate impacts of the option presented for P&R I batch front-
end process vents, we used information from the batch process vent
impacts analysis for the CMAS final rule.\80\ We selected the 90
percent control option model plant shown in Table 3 of this impacts
analysis for sources subject to P&R I (instead of the 85 percent
control option model plant shown in Table 2 of the impacts analysis) to
prevent backsliding of the current P&R I requirements which reflect
MACT instead of the GACT standards of CMAS. We assumed that all
facilities subject to P&R I have batch process vents that would require
control under the option evaluated (i.e., under the option to change
the Group 1 batch front-end process vent threshold to 10,000 lb/yr on
an aggregate vent basis), but as previously mentioned, one facility is
already voluntarily controlling their batch front-end process vents. As
a result, we estimated impacts to the remaining 18 facilities subject
to P&R I.
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\80\ RTI, 2009. Revised Impacts Analysis for Batch Process Vents
Chemical Manufacturing Area Source NESHAP. October 14, 2009. EPA
Docket No. EPA-HQ-OAR-2008-0334-0075.
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Table 16 of this preamble presents the nationwide impacts for the
option considered for batch front-end process vents at P&R I
facilities. We determined that this option is cost effective and we are
proposing, pursuant to CAA section 112(d)(6), to remove 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 in P&R I at 40 CFR
63.482 (these thresholds are currently determined on an individual
batch process vent basis). Instead, owners and operators of batch
front-end process vents that release a total of 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 would be required to reduce
emissions of organic HAP from these process vents using a flare meeting
the proposed operating and monitoring requirements for flares (see
section III.D.1 of this preamble); or reduce emissions of organic HAP
or 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). We solicit comment on the proposed revisions for batch process
vents for P&R I.
Table 16--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for Batch Front-End Process Vents at P&R I Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total VOC emission HAP emission HAP cost
Control option Total capital annualized reductions reductions effectiveness
investment ($) costs ($/yr) (tpy) (tpy) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.................................................................. 811,000 650,700 105 105 6,200
--------------------------------------------------------------------------------------------------------------------------------------------------------
We did not identify any developments in practices, processes, or
control technologies for P&R II process vents that would achieve a
greater HAP emission reduction beyond the emission reduction already
required by P&R II. Therefore, we are not proposing any changes to P&R
II for this emission
[[Page 25132]]
process group based on our technology review.
For further details on all of our assumptions and methodologies we
used in these analyses, 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, which is available in the docket for this
rulemaking.
b. NSPS Subparts III, NNN, and RRR
As previously mentioned, this action presents the EPA's review of
the requirements of 40 CFR part 60, subparts III, NNN, and RRR pursuant
to CAA section 111(b)(1)(B). As described in section II.G.2 of this
preamble, the statutory review of these NSPS focused on whether there
are any emission reduction techniques that are used in practice that
achieve greater emission reductions than those currently required by
these NSPS and whether any of these developments in practices have
become the BSER. Based on this review, we have determined that the BSER
for reducing VOC emissions from these SOCMI processes remain
combustion, and the current standards 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, or use of a flare as an APCD continue to reflect
the BSER. However, we are proposing to remove the alternative of
maintaining a TRE index value greater than 1 without the use of control
device. In addition, we are proposing additional requirements to
provide greater assurance of compliance with the standards. We are also
proposing standards that would apply 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. The rationales for
each of these proposed actions are presented in more detail below.
Pursuant to CAA section 111(a), the proposed NSPS included in this
action would apply to facilities that begin construction,
reconstruction, or modification after April 25, 2023 (see section
III.F.2 of this preamble).
NSPS subparts III, NNN, and RRR regulate vent streams \81\ from:
SOCMI air oxidation units for which construction, reconstruction, or
modification commenced after October 21, 1983 that use air (or a
combination of air and oxygen) as an oxidizing agent to produce one or
more of the chemicals listed in 40 CFR 60.617; SOCMI distillation
operations for which construction, reconstruction, or modification
commenced after December 30, 1983 which produce any of the chemicals
listed in 40 CFR 60.667 as a product; and SOCMI reactor processes for
which construction, reconstruction, or modification commenced after
June 29, 1990 which operate as part of a process unit which produces
any of the chemicals listed in 40 CFR 60.707 as a product. The SOCMI
NSPS subparts III, NNN, and RRR regulate VOC emissions in the form of
TOC. In promulgating these rules, the EPA determined that, for sources
with a TRE index value equal to or less than 1.0, the BSER is the use
of thermal incineration or flare achieving 98 percent by weight control
efficiency or a concentration of 20 ppmv on a dry basis corrected to 3
percent oxygen. At the time of promulgation, the EPA stated that any
control technology can be used to meet BSER as long as it can be
demonstrated that the selected control technology is at least as
effective as BSER at reducing VOC emissions. For affected facilities
with a TRE index value greater than 1.0, BSER is no control and sources
are required to maintain a TRE index value greater than 1.0. As
previously mentioned, the TRE index value is a measure of the
supplemental total resource requirement per unit VOC (or HAP for
NESHAP) reduction (see section III.C.3.a of this preamble). It takes
into account all the resources which are expected to be used in VOC (or
HAP) control by thermal oxidation and provides a dimensionless measure
of resource burden based on cost effectiveness. Resources include
supplemental natural gas, labor, and electricity. Additionally, if the
off-gas contains halogenated compounds, resources will also include
caustic and scrubbing and quench makeup water. For the SOCMI NSPS
subparts III, NNN, and RRR, the TRE index value is derived from the
cost effectiveness associated with VOC control thermal oxidation, and
is a function of vent stream flowrate, vent stream net heating value,
hourly emissions, and a set of coefficients. The TRE index value was
first introduced in an EPA document titled: Guideline Series for
Control of Volatile Organic Compound (VOC) Emissions from Air Oxidation
Processes in Synthetic Organic Chemical Manufacturing Industry (SOCMI)
(see EPA-450/3-84-015, December 1984). In general, similar to the HON
and P&R I, process vents with a TRE index value equal to or less than
1.0 are required to be controlled under SOCMI NSPS III, NNN and RRR.
For additional details regarding the TRE index value (including the
equation and coefficients used to calculate the TRE index value for the
SOCMI NSPS subparts III, NNN, and RRR), 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, which is available in the docket for this rulemaking.
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\81\ 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
(for NSPS subpart III); any gas stream discharged directly from a
distillation facility to the atmosphere or indirectly to the
atmosphere after diversion through other process equipment (for NSPS
subpart NNN); and any gas stream discharged directly from a reactor
process to the atmosphere or indirectly to the atmosphere after
diversion through other process equipment (for NSPS subpart RRR). In
all cases, the vent stream excludes relief valve discharges and
equipment leaks.
---------------------------------------------------------------------------
We reviewed the RACT/BACT/LAER clearinghouse database, other
subsequent EPA, state, and local regulatory development efforts related
to process vents, and responses to our CAA section 114 request for
advances in process operations, design or efficiency improvements, or
other systems of emission reduction.
While we find no change in the BSER for reducing VOC emissions from
air oxidation units, distillation operations, and reactor processes, we
are proposing certain revisions to the current standards. First, we are
proposing to remove the option of maintaining a TRE index value greater
than 1 as an alternative to controlling emissions. We are proposing
this change based on the following observations we made with respect to
the NSPS TRE index. We observed that some facilities subject to NSPS
subpart III, NNN, and/or RRR are voluntarily controlling process vents
even though such control is not required under the applicable NSPS
because their calculated NSPS TRE index value is greater than 1. At
least three HON facilities that are also subject to at least one of the
three process vent NSPS confirmed in response to our CAA section 114
request, that they were voluntarily controlling some of their Group 2
process vents even though control is not required under either the HON
or the applicable NSPS. We expect
[[Page 25133]]
other facilities that are subject to the HON and at least one of the
NSPS subparts III, NNN, and RRR will do this too because some
facilities stated in their response to the CAA section 114 request
that, pursuant to 40 CFR 63.113(h), many of their process vents are
voluntarily designated as HON Group 1 process vents ``so that TRE
calculations are not required.'' In other words, some facilities are
likely electing to control certain process vents that have TRE index
values greater than 1.0. In addition, based on the responses to our CAA
section 114 request, we observed that facilities are routing multiple
process vents to a single APCD. This is significant because the current
use of the TRE index value is only based on controlling a single
process vent with a single APCD, an unrealistic scenario when compared
to how chemical manufacturing facilities actually control their process
vents. It is much more likely that a facility routes numerous process
vents to the same APCD. For the reason stated above, we no longer
believe that TRE index value accurately represents the BSER, and
because a single APCD can control emissions from multiple process
vents, control could be cost-effective even at a TRE index value of
greater than 1. Finally, also based on responses to our CAA section 114
request, one HON and P&R I facility (that is also subject to all three
process vent NSPS) provided over 300 pages of modeled runs that were
used to help the facility determine certain characteristics of their
process vents for inputs to HON and P&R I TRE index value calculations.
We reviewed this information and concluded that determining a TRE index
value for certain process vent streams is often theoretical, can be
extremely complicated, and is uncertain. In addition, because the TRE
index value is largely a theoretical characterization tool, it can be
very difficult to enforce. In order to calculate a TRE index value,
owners and operators must determine numerous input values; and without
the correct amount of process knowledge, verifying inputs can be
problematic. We evaluated the cost of requiring that a facility control
all process vents irrespective of its TRE index value and the average
cost per facility is provided in Table 17 of this preamble. In
addition, given the complexity of chemical manufacturing facilities and
their use of APCDs (e.g., integrated with numerous emission sources
subject to various chemical manufacturing related NSPS and NESHAP), we
found the cost to be cost effective based on the cost-effectiveness we
evaluated for four different NSPS triggering scenarios described
further below (see Table 18 of this preamble). For the reasons stated
above, we believe that proposing to remove the option to maintain a
greater than 1 TRE index value as an alternative to emission reduction
under NSPS subparts IIIa, NNNa, and RRRa make practical and enforceable
sense. In other words, for NSPS subparts IIIa, NNNa, and RRRa, we are
proposing owners and operators reduce emissions of total organic carbon
(TOC) (minus methane and ethane) from all vent streams of an affected
facility (i.e., SOCMI air oxidation unit processes, distillation
operations, reactor processes for which construction, reconstruction,
or modification 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,
whichever is less stringent, or combust the emissions in a flare
meeting more stringent operating and monitoring requirements for flares
(we discuss these flare requirements further below in this section)
(see proposed 40 CFR 612a(a), 40 CFR 60.662a(a), and 40 CFR
60.702a(a)).
We are also proposing to tighten up the requirements for flares.
All three NSPS subparts allow the use of a flare in accordance with the
flare general provisions at 40 CFR 60.18 as an alternative to meeting
the numeric standards. The EPA had previously believed flares could
achieve 98 percent emission reduction if it were operated in accordance
with 40 CFR 60.18. See, e.g., 55 FR 26913. Because the NSPS reflect the
BSER under conditions of proper operation and maintenance, in doing its
review, we also evaluate and determine the proper testing, monitoring,
recordkeeping and reporting requirements needed to ensure compliance
with the emission standards. In doing so, in our review of several
chemical and petrochemical sector related NESHAP, such as MON, the
EMACT standards, and Petroleum Refineries NESHAP, we identified new
operating and monitoring requirements for flares that are different
than those specified in 40 CFR 60.18.\82\ The EPA included these flare
requirements in recent RTR rulemakings in order to ensure flares used
as APCDs achieve 98 percent HAP destruction efficiencies and these
flare requirements are also being proposed for HON and P&R I (this is
discussed in detail in section III.D.1 of this preamble). We evaluated
the costs of these improved flared requirements and the average cost
per facility is provided in Table 17 of this preamble. In addition,
given the complexity of chemical manufacturing facilities and their use
of APCDs (e.g., integrated with numerous emission sources subject to
various chemical manufacturing related NSPS and NESHAP), we found the
cost to be cost effective based on the cost-effectiveness we evaluated
for four different NSPS triggering scenarios described further below
(see Table 18 of this preamble). In light of the above, we are
proposing to include in the new NSPS subparts the same operating and
monitoring requirements for flares that we are proposing for flares
subject to the HON and P&R I (see proposed 40 CFR 619a, 40 CFR 60.669a,
and 40 CFR 60.709a).
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\82\ In general the differences include: new requirements to
operate pilot flame systems continuously and that flares operate
with no visible emissions (except for periods not to 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; new
requirements related to flare tip velocity and the combustion zone
gas; and new work practice standards related to the visible
emissions and velocity limits during periods when the flare is
operated above its smokeless capacity (e.g., periods of emergency
flaring). For the specific flare requirements, refer to: 40 CFR
63.1103(e)(4) (EMACT standards), 40 CFR 63.2450(e)(5) (MON), and 40
CFR 63.670 and 40 CFR 63.671 (Petroleum Refinery Sector rule).
---------------------------------------------------------------------------
Third, we are proposing to amend the definition of vent streams
such that the emission standards would also apply to PRD emissions.
Currently, the NSPS subparts III, NNN, and RRR exclude ``relief valve
discharges'' from the definition of vent stream (see 40 CFR 60.611, 40
CFR 60.661, and 40 CFR 60.701) and therefore, emissions from PRDs \83\
are currently excluded from emissions standards in these NSPS. However,
the preambles to the proposed and final subparts were silent on the
reason for this exclusion in the definition of a ``vent stream.''
Further, in reviewing the RACT/BACT/LAER clearinghouse database, we
identified at least one SOCMI facility that has requirements for
reactor process vents such that no PRD may emit directly to the
atmosphere under any circumstance, and the capture system must be
inspected regularly to verify integrity. In light of the above, we are
proposing to the ``vent stream'' definition to remove the exclusion of
``relief valve discharge.''
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\83\ The acronym ``PRD'' means pressure relief device and is
common vernacular to describe a variety of devices regulated as
relief valve discharges.
---------------------------------------------------------------------------
Fourth, we are proposing to expressly prohibit emissions from
affected facilities bypassing an APCD at any time. In our review of
several chemical and petrochemical sector related NESHAP, none of the
rules allow regulated emissions from a process vent to bypass an APCD
at any time, and if a bypass is used, it is considered a
[[Page 25134]]
violation and the owner or operator is required to estimate and report
the quantity of regulated emissions released.\84\ The EPA included
these requirements for bypasses in recent RTR rulemakings because
bypassing an APCD could result in a release of regulated emissions from
a process vent into the atmosphere.\85\ Currently, the NSPS subparts
III and NNN do not contain any requirements for bypass lines, and NSPS
subpart RRR only requires owners and operators to document when a vent
stream being routed to an APCD is diverted through a bypass line
resulting in emissions to the atmosphere; therefore, it is unclear
whether the current standards prohibit bypassing an APCD, which could
result in a release of otherwise regulated emissions from a process
vent into the atmosphere. We are therefore proposing in NSPS subparts
IIIa, NNNa, and RRRa that an owner or operator may not bypass the APCD
at any time, that a bypass is a violation (see proposed 40 CFR
60.612a(b)(2), 40 CFR 60.662a(b)(2), and 40 CFR 60.702a(b)(2)), and
that owners and operators must estimate and report the quantity of TOC
released should any such violation occur (see proposed 40 CFR
60.615a(d)(1) and (2), 40 CFR 60.665a(d)(1) and (2), and 40 CFR
60.705a(d)(1) and (2)).
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\84\ See 40 CFR 63.1103(e)(6), 40 CFR 63.1109(g), and 40 CFR
63.1110(e)(6) (EMACT standards); 40 CFR 63.2450(e)(6), 40 CFR
63.2520(e)(12), and 40 CFR 63.2525(n) (MON); and 40 CFR 63.644(c),
40 CFR 63.660(i)(2), and 40 CFR 63.655(g)(6)(iii) and (i)(4)
(Petroleum Refinery Sector rule).
\85\ See 85 FR 40386, July 6, 2020 (EMACT standards), 85 FR
49084, August 12, 2020 (MON), and 80 FR 75178, December 1, 2015
(Petroleum Refinery Sector rule).
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Also, we are proposing in the new NSPS subparts additional control
device requirements for adsorbers when such APCD is used to meet the
emission standards in the applicable NSPS. In our review of the MON, we
identified requirements for adsorbers that cannot be regenerated and
regenerative adsorbers that are regenerated offsite (see 40 CFR
63.2450(e)(7)). The MON requires owners and operators of this type of
APCD to use dual adsorbent beds in series and conduct daily monitoring
because the use of a single bed does not ensure continuous compliance
unless the bed is replaced well before breakthrough.\86\ The EPA
included these requirements in their recent RTR rulemaking for MON in
order to ensure owners and operators monitor for performance
deterioration for these specific types of APCDs and these requirements
are also being proposed for HON and P&R I (see section III.E.5.b of
this section for additional information about this). Currently, the
NSPS subparts III, NNN, and RRR do not contain any requirements for
adsorbers that cannot be regenerated and regenerative adsorbers that
are regenerated offsite. We evaluated the cost of these requirements
for adsorbers and the average cost per facility is provided in Table 17
of this preamble. In addition, given the complexity of chemical
manufacturing facilities and their use of APCDs (e.g., integrated with
numerous emission sources subject to various chemical manufacturing
related NSPS and NESHAP), we found the cost to be cost effective based
on the cost-effectiveness we evaluated for four different NSPS
triggering scenarios described further below (see Table 18 of this
preamble); therefore, in order to ensure that continuous compliance is
achieved for NSPS subpart IIIa, NNNa, and RRRa facilities at all times
when controlling VOC emissions (i.e., for those facilities that choose
to use adsorbers that cannot be regenerated and regenerative adsorbers
that are regenerated offsite as BSER to meet the 98-percent control or
a 20 ppmv TOC outlet concentration emission standard), we are proposing
to include at 40 CFR 60.613a(a)(6), 40 CFR 60.663a(a)(6), and 40 CFR
60.703a(a)(6) the same monitoring requirements for adsorbers that
cannot be regenerated and regenerative adsorbers that are regenerated
offsite that we are proposing for the HON and P&R I.
---------------------------------------------------------------------------
\86\ According to the MON, ``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.
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Lastly, consistent with Sierra Club v. EPA, 551 F.3d 1019 (D.C.
Cir. 2008),\87\ we are proposing standards for periods of startup and
shutdown, which are currently not subject to the emission standards in
NSPS subparts III, NNN and RRR. For this effort, we identified, as part
of our review of the RACT/BACT/LAER clearinghouse database, some SOCMI
facilities in Texas that have specific requirements related to
maintenance, startup, and shutdown for equipment and vessel openings
related to process vents (i.e., opening air oxidation unit processes,
distillation operations, and reactor processes) and we found that these
requirements are included in several SOCMI related NESHAP (i.e., EMACT
standards, the MON, and/or the petroleum refineries NESHAP) (we discuss
these requirements further below in this section of the preamble).
Given that many SOCMI processes that are subject to the SOCMI NSPS are
also located at chemical plants subject to these related NESHAP and
these facilities use the same APCDs to comply with all of these rules
(to reduce both VOC and HAP emissions), we also examined the process
vent provisions from each of these rules. Review of the NESHAP
standards mentioned above revealed several related requirements that
did not exist at the time the EPA promogulated NSPS subparts III, NNN,
and RRR.
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\87\ In Sierra Club, the court vacated the SSM exemption
contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1). The court
explained that under section 302(k) of the CAA, emissions standards
or limitations must be continuous in nature and that an SSM
exemption violates this requirement. The EPA believes the reasoning
in Sierra Club applies equally to section 111 standards.
---------------------------------------------------------------------------
As previously mentioned in our review of the RACT/BACT/LAER
clearinghouse database and as found in our review of in several
chemical and petrochemical sector related NESHAP,\88\ the EPA has
included a work practice standard for maintenance vents requiring
owners and operators to meet certain conditions before they open
equipment to the atmosphere, including opening equipment to the
atmosphere that are related to NSPS process vents (e.g., air oxidation
units, distillation operations, and reactor processes). This work
practice standard requires 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 pounds 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.\89\ We evaluated the cost
associated with this work practice standard and the average cost per
facility is provided in Table 17 of this preamble. In addition, given
the complexity of chemical manufacturing facilities and their use of
APCDs (e.g., integrated with numerous emission
[[Page 25135]]
sources subject to various chemical manufacturing related NSPS and
NESHAP), we found the cost to be cost effective based on the cost-
effectiveness we evaluated for four different NSPS triggering scenarios
described further below (see Table 18 of this preamble). We determined
that these work practice standards for maintenance vents (i.e.,
equipment openings related to process vents) is a technique used in
practice that achieves emission reductions 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. 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.'' Equipment openings related to process vents
are not ``emitted through a conveyance designed and constructed to emit
or capture such pollutant'' (see CAA section 111(h)(2)) and it is not
possible to characterize each of these potential release points. For
these reasons (which are the same reasons we discuss in section
III.D.4.a of this preamble for including a work practice standard for
maintenance activities in the HON and P&R I), we are proposing these
work practice standards for maintenance vents in NSPS subparts IIIa,
NNNa, and RRRa as the standards reflecting the BSER during periods of
startup and shutdown (see proposed 40 CFR 612a(c), 40 CFR 60.662a(c),
and 40 CFR 60.702a(c)).
---------------------------------------------------------------------------
\88\ See 40 CFR 63.1103(e)(5) (EMACT standards), 40 CFR
63.2450(v) (MON), and 40 CFR 63.642(c) (Petroleum Refinery Sector
rule).
\89\ The EPA added these equipment opening requirements in the
recent RTR to be consistent with Sierra Club.
---------------------------------------------------------------------------
As mentioned above, we analyzed cost and emission reductions as
part of our evaluation of each of the options considered above. We used
the average cost and emission reductions that we determined for process
vents subject to the HON to evaluate the costs, emission reductions,
and cost-effectiveness of each of the options considered above for NSPS
subparts IIIa, NNNa, and RRRa. Table 17 of this preamble summarizes
these average HON cost and emission reductions.
Table 17--Average Cost and Emission Reductions for Process Vents Subject to the HON Used for the Suite of
Proposed Process Vent Requirements Evaluated for the NSPS Subparts IIIa, NNNa, and RRRa
----------------------------------------------------------------------------------------------------------------
Total annual VOC emission
Description Total capital Total annual cost w/recovery reductions
investment ($) cost ($/yr) credits ($/yr) (tpy)
----------------------------------------------------------------------------------------------------------------
Flare monitoring requirements \1\............. 3,752,200 789,200 789,200 93
Maintenance vent requirements \2\............. .............. 460 460 ..............
Revising the standard from a TRE calculation 39,300 98,400 98,400 9.1
to control of all vent streams \3\...........
Adsorber monitoring (carbon cannisters) \4\... 26,500 2,500 2,500 0.21
----------------------------------------------------------------------------------------------------------------
\1\ For additional details, see the document titled Control Option Impacts for Flares Located in the SOCMI
Source Category that Control Emissions from Processes Subject to HON and for Flares that Control Emissions
from Processes Subject to Group I and Group II Polymers and Resins NESHAPs, which is available in the docket
for this rulemaking.
\2\ For additional details, see the document titled Review of Regulatory Alternatives for Certain Vent Streams
in the SOCMI Source Category that are Associated with Processes Subject to HON and Processes Subject to Group
I and Group II Polymers and Resins NESHAPs, which is available in the docket for this rulemaking.
\3\ For additional details, 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, which is available in the docket for this rulemaking.
\4\ For additional details, see the document titled Analysis of Monitoring Costs and Dual Bed Costs for Non-
Regenerative Carbon Adsorbers Used in the SOCMI Source Category that are Associated with Processes Subject to
HON and for Non-Regenerative Carbon Adsorbers that are Associated with Processes Subject to Group I Polymers
and Resins NESHAP, which is available in the docket for this rulemaking.
We also evaluated the costs of requiring the suite of proposed
requirements described above to SOCMI nationwide. We conducted an
analysis to estimate how many non-HON NSPS affected facilities are
expected/projected to be subject to the suite of proposed process vent
requirements presented above. Given that we are proposing these same
suite of process vent requirements for HON facilities, we only
considered non-HON NSPS affected facilities here under CAA section 111
so as to not double count cost and emission reductions from affected
facilities that are subject to both these SOCMI NSPS and the HON. An
affected facility can become subject to SOCMI NSPS subpart IIIa, NNNa,
or RRRa under one of the following scenarios: (1) The affected facility
is at a new greenfield facility; (2) the affected facility is a new
affected facility at an existing plant site; (3) an existing affected
facility is modified; or (4) an existing affected facility triggers the
reconstruction requirements. For scenario 1 (i.e., affected facility is
at a new greenfield facility), we assumed only one non-HON greenfield
facility will trigger NSPS subpart IIIa, NNNa, or RRRa over the next 5
years (we do not expect any non-HON greenfield facilities, but to be
comprehensive in our analysis, we assumed one). For comprehensiveness,
we also assumed this greenfield facility would not be subject to the
EMACT standards, MON, and Petroleum Refinery Sector rule; and the
facility will use one flare and one non-flare APCD to control all their
process vents from SOCMI NSPS unit operations. We used facility
responses to our CAA section 114 request to help us determine the
number of facilities that could potentially trigger scenarios 2, 3, and
4.
For scenario 2 (i.e., new affected facilities constructed at
existing plant sites), we estimate six new affected facilities will be
built and be subject to new requirements in a new NSPS subpart IIIa,
NNNa, or RRRa over the next 5 years. Facilities responding to our CAA
section 114 request had 500 unit operations subject to either NSPS
subpart III, NNN, or RRR; and only one of these unit operations was new
construction in the last 5 years and not subject to the HON. We
determined that there are currently 284 SOCMI facilities subject to
either NSPS subpart III, NNN, or RRR; and 196 of these are non-HON-
subject facilities.\90\ Based on responses
[[Page 25136]]
to our CAA section 114 request, HON facilities have on average 45 unit
operations per facility. Assuming non-HON facilities are smaller, we
estimate that non-HON facilities subject to either NSPS subpart III,
NNN, or RRR have 15 unit operations per facility. Assuming the same
distribution of new construction for non-HON facilities, we estimate
that six new affected facilities (one new unit operation per non-HON
facility subject to either NSPS subpart III, NNN, or RRR), would have
been constructed in the last 5 years (1/500*15*196). This analysis
assumes that the same number of unit operations that were constructed
in the last 5 years would be constructed in the next 5 years. We then
assumed two of the six new affected facilities (or about 33 percent)
are collocated at a petroleum refinery, MON, and/or EMACT facility.
Therefore, two of the six unit operations would already be complying
with requirements in the NSPS (because of the NESHAP); and we also
assumed that of the remaining four new unit operations, two will not
use a flare to comply with the NSPS.
---------------------------------------------------------------------------
\90\ As of March 2022, according to the OECA's ECHO tool, there
were 284 facilities located in the United States that are
potentially 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, which is available in the docket for this
rulemaking.
---------------------------------------------------------------------------
For Scenarios 3 and 4 (i.e., existing facility is modified or
reconstructed), we estimate 12 existing affected facilities will
trigger new requirements in a new NSPS subpart IIIa, NNNa, or RRRa over
the next 5 years due to modification or reconstruction. As mentioned
previously, facilities responding to our CAA section 114 request had
500 unit operations subject to either III, NNN, or RRR; however, only
two of these unit operations were modified or reconstructed in the last
5 years and not subject to the HON. Using similar procedure as
described above for scenario 2, we estimate that 12 modified or
reconstructed affected facilities (one modified or reconstructed unit
operation per non-HON facility subject to the NSPS), would have been
modified or reconstructed in the last 5 years (2/500*15*196). This
analysis assumes that the same number of unit operations that were
modified or reconstructed in the last 5 years would be modified or
reconstructed in the next 5 years. We then assumed four of the 12 (or
about 33 percent) modified or reconstructed affected facilities are
collocated at a refinery, MON, and/or EMACT facility. Therefore, four
of the 12 unit operations are already complying with requirements in
the NSPS (because of the NESHAP); and we also, assumed that of the
remaining eight modified or reconstructed unit operations, four will
not use a flare to comply with the NSPS.
Table 18 of this preamble below presents the nationwide impacts for
the suite of proposed process vent requirements presented above that we
considered for vent streams subject to new NSPS subparts IIIa, NNNa,
and RRRa. The cost-effectiveness for the suite of process vent
requirements evaluated under this NSPS review is $4,570 per ton VOC
(cost-effectiveness w/recovery credits), which we consider to be cost
effective. 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, which is available
in the docket for this rulemaking, for details on the assumptions and
methodologies used in this analysis.
For the reasons stated above, pursuant to CAA section 111(b)(1)(B),
we are proposing new SOCMI NSPS to: (1) Remove the TRE index value
concept in its entirety and require all process vents from an affected
facility be controlled; (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) prohibit an owner or operator from
bypassing the APCD at any time, and to report any such violation
(including the quantity of TOC released to the atmosphere); (4) require
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) require 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) add control device
operational and monitoring requirements for adsorbers that cannot be
regenerated and regenerative adsorbers that are regenerated offsite
(see section III.E.5.b of this preamble). We are proposing that
affected facilities that are constructed, reconstructed, or modified
after April 25, 2023 would be subject to these proposed requirements in
NSPS subparts IIIa, NNNa, and/or RRRa.
Table 18--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for Non-HON Vent
Streams Triggering NSPS Subparts IIIa, NNNa, and/or RRRa
----------------------------------------------------------------------------------------------------------------
Cost-
Total annual VOC emission effectiveness
Scenario Total capital Total annual cost w/ reductions w/recovery
investment ($) cost ($/yr) recovery (tpy) credits ($/ton
credits ($/yr) VOC)
----------------------------------------------------------------------------------------------------------------
Scenario 1 (i.e., one affected 1,665,300 461,000 461,000 93 4,960
facility at a new greenfield
facility)......................
Scenario 2 (i.e., new affected 7,609,500 1,780,000 1,780,000 392 4,540
facility at six existing
facilities)....................
Scenarios 3 and 4 (i.e., 12 15,192,500 3,558,000 3,558,000 783 4,540
existing affected facilities
modified or triggers the
reconstruction requirements)...
-------------------------------------------------------------------------------
Total....................... 24,467,300 5,799,800 5,799,800 1,269 4,570
----------------------------------------------------------------------------------------------------------------
4. Standards for Transfer Racks
We did not identify any developments in practices, processes, or
control technologies for HON transfer racks that would achieve a
greater HAP emission reduction beyond the emission reduction already
required by the HON. Therefore, under CAA section 112(d)(6) we are not
proposing any changes to the
[[Page 25137]]
HON for this emission process group based on our technology review.\91\
We note, however, that under CAA section 112(d)(2) and (3) we are
proposing changes to the applicability threshold for HON transfer racks
to fill a regulatory gap in the current HON (see section III.D.8 of
this preamble).
---------------------------------------------------------------------------
\91\ P&R I and P&R II sources do not have transfer racks as
emission sources.
---------------------------------------------------------------------------
5. Standards for Wastewater
As previously mentioned, HAP are emitted into the air from
wastewater collection, storage, and treatment systems that are
uncovered or open to the atmosphere through volatilization of organic
compounds at the liquid surface. Emissions occur by diffusive or
convective means, or both. Diffusion occurs when organic concentrations
at the water surface are much higher than ambient concentrations. The
organics volatilize, or diffuse into the air, to reach equilibrium
between aqueous and vapor phases. Convection occurs when air flows over
the water surface, sweeping organic vapors from the water surface into
the air. The rate of volatilization is related directly to the speed of
the air flow over the water surface.
The HON defines wastewater to mean water that: (1) Contains either:
(i) an annual average concentration of Table 9 (to NESHAP subpart G)
compounds of at least 5 ppmw and has an annual average flow rate of
0.02 liter per minute (lpm) or greater or (ii) an annual average
concentration of Table 9 (to NESHAP subpart G) compounds of at least
10,000 ppmw at any flow rate, and that (2) is discarded from a CMPU
that meets all of the criteria specified in 40 CFR 63.100 (b)(1)
through (3). Wastewater is process wastewater or maintenance
wastewater. For process and maintenance wastewaters and certain liquid
streams in open systems within a CMPU, the HON defines Group 1
wastewater streams at existing sources as having: either a total annual
average concentration of Table 9 (to NESHAP subpart G) compounds
greater than or equal to 10,000 ppmw at any flow rate; or a total
annual average concentration of compounds in Table 9 to NESHAP subpart
G greater than or equal to 1,000 ppmw, and the annual average flow rate
is greater than or equal to 10 liter per minute. NESHAP subpart G
provides owners and operators several control options for wastewater
tanks, surface impoundments, containers, individual drain systems, and
oil-water separators. NESHAP subpart G also specifies performance
standards for treating wastewater streams using open or closed
biological treatment systems or using a design steam stripper with vent
control. For APCDs (e.g., thermal oxidizers) used to control emissions
from collection system components, steam strippers, or closed
biological treatment, NESHAP subpart G provides owners or operators
several compliance options, including 95-percent destruction
efficiency, a 20 ppmv outlet concentration, or design specifications
for temperature and residence time.
P&R I defines wastewater similarly to how the term is defined in
the HON, except instead of referring to Table 9 (to NESHAP subpart G)
compounds, P&R I refers to Table 5 (to NESHAP subpart U) compounds. The
standards for wastewater in NESHAP subpart U refer to the provisions in
NESHAP subpart G. Generally, the P&R I Group 1 wastewater threshold is
the same as in the HON, except P&R I refers to compounds that meet the
definition of organic HAP in 40 CFR 63.482 in addition to those listed
in table 9 of NESHAP subpart G, and P&R I exempts wastewater that
pertain solely and exclusively to organic HAP listed on table 8 of
NESHAP subpart G).
P&R II defines wastewater as aqueous liquid waste streams exiting
equipment at an affected source. No further stratification into groups
for applicability is specified. As previously mentioned, process vents,
storage tanks, and wastewater systems \92\ combined are regulated
according to a production-based emission rate (e.g., pounds HAP per
million pounds BLR or WSR produced) standard for existing sources in
both BLR (130 pounds) and WSR (10 pounds). For new sources, BLR sources
require 98 percent reduction or an overall limit of 5,000 pounds of HAP
per year. New WSR sources are limited to 7 pounds of HAP per million
pounds WSR produced.
---------------------------------------------------------------------------
\92\ P&R II defines a wastewater system as a system made up of a
drain system and one or more waste management units; and a
wastewater management unit means any component, piece of equipment,
structure, or transport mechanism used in storing, treating, or
disposing of wastewater streams, or conveying wastewater between
storage, treatment, or disposal operations.
---------------------------------------------------------------------------
As part of our CAA section 112(d)(6) technology review for HON and
P&R I wastewater streams, we evaluated tightening the HON and P&R I
wastewater Group 1 applicability thresholds. Specifically, we evaluated
the option (option 1) to require owners and operators to manage and
treat existing wastewater streams with total annual average
concentration of Table 9 (to NESHAP subpart G) compounds (for HON) and
Table 5 (to NESHAP subpart U) compounds (for P&R I) greater than or
equal to 1,000 ppmw at any flow rate; or greater than or equal to 10
ppmw at a flow rate of 10 lpm or greater. We did not identify any
control options for P&R II wastewater streams.
Table 19 of this preamble presents the nationwide costs and impacts
for the wastewater stream control option considered for HON facilities.
Table 20 of this preamble presents the nationwide costs and impacts for
the wastewater stream control option considered for P&R I facilities.
For details on the assumptions and methodologies used in this analysis,
see the document titled Clean Air Act Section 112(d)(6) Technology
Review for Wastewater Streams Located in the SOCMI Source Category that
are Associated with Processes Subject to HON and for Wastewater Streams
that are Associated with Processes Subject to Group I and II Polymers
and Resins NESHAP, which is available in the docket for this
rulemaking.
We determined that the option to revise wastewater stream Group 1
threshold applicability (i.e., to require control of existing
wastewater streams with total annual average concentration of Table 9
to subpart G compounds (for HON) or Table 5 to 40 CFR 63, subpart U
compounds (for P&R I) greater than or equal to 1,000 ppmw at any flow
rate; or greater than or equal to 10 ppmw at a flow rate of 10 lpm or
greater) is not cost effective based on the costs and emission
reductions presented. Therefore, we are not proposing to revise the HON
and P&R I to reflect the requirements of this option pursuant to CAA
section 112(d)(6). Also, we did not identify any developments in
practices, processes, or control technologies for P&R II wastewater
that would achieve a greater HAP emission reduction beyond the emission
reduction already required by P&R II. Therefore, we are not proposing
any changes to P&R II for this emission process group based on our
technology review.
[[Page 25138]]
Table 19--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for Wastewater Streams at HON Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total VOC emission HAP emission HAP cost
Control option Total capital annualized reductions reductions effectiveness
investment ($) costs ($/yr) (tpy) (tpy) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.................................................................. 504,766,000 210,739,500 2,755 2,755 76,500
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 20--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for Wastewater Streams at P&R I Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total VOC emission HAP emission HAP cost
Control option Total capital annualized reductions reductions effectiveness
investment ($) costs ($/yr) (tpy) (tpy) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.................................................................. 46,847,800 22,548,200 220 220 102,500
--------------------------------------------------------------------------------------------------------------------------------------------------------
6. Standards for Equipment Leaks
As previously mentioned, emissions of VOC and HAP from equipment
leaks occur in the form of gases or liquids that escape to the
atmosphere through many types of connection points (e.g., threaded
fittings) or through the moving parts of certain types of process
equipment during normal operation. Equipment regulated by the HON, P&R
I, and P&R II includes agitators, compressors, connectors,
instrumentation systems, OEL, PRDs, pumps, sampling collection systems,
and valves \93\ 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. The results of our CAA section 112(d)(6)
technology review for equipment leaks associated with HON, P&R I, and
P&R II processes are discussed in section III.C.6.a of this preamble.
Equipment regulated by NSPS subpart VVa includes connectors,
compressors, PRDs, pumps, sampling collection systems, OEL, and valves
that contain or contact material that are 10 percent by weight or more
of VOC, operate 300 hours per year or more, and are not in vacuum
service. The results of our CAA 111(b)(1)(B) review for equipment leaks
subject to NSPS subpart VVa are discussed in section III.C.6.b of this
preamble.
---------------------------------------------------------------------------
\93\ We believe P&R II contains a typographical error in that
valves are currently excluded from the definition of equipment leaks
at 40 CFR 63.522; see section III.D.10 of this preamble for our
rationale for this conclusion and our proposal to address this
issue.
---------------------------------------------------------------------------
a. HON, P&R I, and P&R II
The HON, P&R I, and P&R II standards for BLR, require owners or
operators to meet the control requirements of NESHAP subpart H which
contains the MACT standard for equipment leaks, including LDAR
provisions and other control requirements. Subpart H was also
identified in P&R II as the appropriate level of control for facilities
producing WSR, but additional compliance options were allowed in the
P&R II rule for WSR sources. We are proposing to no longer allow the
additional compliance options for WSR sources, and to require that all
sources comply with the HON equipment leaks regulations (see section
III.D.10 of this preamble for further details about this proposed
amendment). 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 generally must be conducted using EPA Method 21 in
appendix A-7 to 40 CFR part 60 or other approved equivalent monitoring
techniques. The equipment leak HON, P&R I, and P&R II requirements vary
by equipment (component) type but require LDAR using monitoring with
EPA Method 21 of appendix A-7 to 40 CFR part 60 at certain frequencies
(e.g., monthly, quarterly, every 2 quarters, annually) and have varying
leak definitions (e.g., 500 ppm, 1,000 ppm, 10,000 ppm) depending on
the type of service (e.g., gas and vapor service or in light liquid
service). The LDAR requirements for components in heavy liquid service
include sensory monitoring (e.g., visual, audible, olfactory).
The practices, processes, and control technologies considered
during MACT development for equipment leaks at HON, P&R I, and P&R II
facilities included LDAR. To identify developments for the technology
review, we reviewed responses to our CAA section 114 request, the BACT/
LAER database, and evaluated other federal regulations (i.e., the
Petroleum Refinery Sector rule, MON, and NSPS subpart VVa) and state
regulations (i.e., the Texas fugitive emissions rules \94\ applicable
to petrochemical processes). Also, the EPA conducted a general analysis
in a 2011 equipment leaks study \95\ to identify the latest
developments in practices, processes, and control technologies for
equipment leaks at chemical manufacturing facilities and petroleum
refineries and estimated the impacts of applying those practices,
processes, and control technologies to model facilities. We used this
2011 equipment leaks analysis as a reference for conducting the
technology review for equipment leaks at HON, P&R I, and P&R II
facilities.
---------------------------------------------------------------------------
\94\ 30 TAC 115, subchapters D and H, Division 3.
\95\ Hancy. 2011. Memorandum from Hancy, C., RTI International
to Howard, J., EPA/OAQPS. Analysis of Emissions Reduction Techniques
for Equipment Leaks. December 21, 2011. EPA Docket ID No. EPA-HQ-
OAR-2010-0869.
---------------------------------------------------------------------------
Our technology review for equipment leaks of HAP (e.g., broader
than the EtO discussed in section II.B.2.a.ii of this preamble)
identified several developments in LDAR practices and processes: (1)
Lowering the leak definition for valves in light liquid service from
500 ppm to 100 ppm with monthly monitoring and skip periods; (2) in
addition to requirements specified in option 1, lowering the leak
definition for valves in gas and vapor service from 500 ppm to 100 ppm
with monthly monitoring and skip periods; and (3) in addition to
requirements specified in option 2, lowering the leak definition for
pumps in light liquid service from 1,000 ppm to 500 ppm with monthly
monitoring. For all other component types, we did not identify
developments in LDAR practices and processes in the chemical
sector.\96\
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\96\ We note that while other technologies such as optical gas
imaging and sensor networks may be considered developments in
monitoring for equipment leaks, the EPA did not evaluate these
options further as we have insufficient information on how use of
such monitoring technology compares to current EPA Method 21
practices for chemical sector sources and we are soliciting comment
on these technologies. See section V of this preamble for more
details.
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[[Page 25139]]
Emissions reductions were estimated for the new developments that
we identified using component counts and emission factors. The
component counts were derived using data provided to the EPA in
response to our CAA section 114 request (see section II.C of this
preamble). We developed model component counts for 207 HON facilities,
19 P&R I facilities (and 10 of the P&R I facilities are collocated with
HON processes), and 5 P&R II facilities (and 3 of the P&R II facilities
are collocated with HON processes). We then multiplied the number of
nationwide HON, P&R I, and P&R II processes \97\ by the model component
counts to estimate the nationwide component counts. Subsequently,
baseline emissions and emissions after implementation of the controls
for each component were calculated using these nationwide component
counts and emission factors and leak frequencies for the chemical
manufacturing industry from the 2011 equipment leaks study.
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\97\ We used information from the 2006 RTR HON proposal preamble
(see pg. 34434: https://www.govinfo.gov/content/pkg/FR-2006-06-14/pdf/06-5219.pdf) to estimate the number of HON CMPUs nationwide. In
2006, the EPA estimated 729 CMPUs nationwide from 238 HON facilities
based off information from the American Chemistry Council. We scaled
this data to 207 HON facilities [(207 x 729)/238 = 634]. For P&R I
facilities we assumed 1 EPPU per facility resulting in 19 EPPU's.
For P&R II facilities we assumed each facility had 1 process unit
associated with either WSR or BLR processes resulting in 5 process
units total.
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Costs were then calculated for the baseline and control options,
which reflect the cost to implement an LDAR program for each component.
Note that the difference between the costs for the baseline and control
options is the incremental cost to comply with the controls.
Furthermore, because the control options result in chemicals in process
lines not leaking and therefore, not being lost, we present costs both
with and without this consideration. To estimate savings in chemicals
not being emitted (i.e., lost) due to the equipment leak control
options, we applied a recovery credit of $900 per ton of VOC to the
emission reductions in the analyses.
We calculated the VOC and HAP cost effectiveness by dividing the
incremental annual costs by the emissions reductions. Table 21 of this
preamble presents the nationwide costs and impacts for the suite of
equipment leak control options considered for HON facilities (including
10 P&R I facilities and 3 P&R II facilities collocated with HON
facilities). Table 22 of this preamble presents the nationwide costs
and impacts for the suite of equipment leak control options considered
for P&R I facilities (not collocated with HON facilities). Table 23 of
this preamble presents the nationwide costs and impacts for the suite
of equipment leak control options considered for P&R II facilities (not
collocated with HON facilities). For details on the assumptions and
methodologies used in this analysis, see the document titled Clean Air
Act Section 112(d)(6) Technology Review for Equipment Leaks Located in
the SOCMI Source Category that are Associated with Processes Subject to
HON and for Equipment Leaks that are Associated with Processes Subject
to Group I and II Polymers and Resins NESHAP, which is available in the
docket for this rulemaking.
Based on the costs and emission reductions for each of the options,
we determined that none of them are cost effective. Therefore, we are
not proposing to revise the HON, P&R I, and P&R II to reflect the
requirements of these options pursuant to CAA section 112(d)(6).
Table 21--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for HON Equipment Not in EtO Service
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average
Total Total Average HAP Average HAP incremental
Total capital annualized annualized HAP emission cost cost HAP cost
Control option investment ($) costs w/o costs with reductions effectiveness effectiveness effectiveness
credits ($/yr) credits ($/yr) (tpy) with credits w/o credits ($/ with credits
($/ton) ton) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1....................................... 2,079,000 538,400 393,000 16 25,000 34,000 ..............
2....................................... 3,637,000 872,000 672,000 22 31,000 40,000 47,000
3....................................... 4,926,00 1,325,000 1,105,000 24 46,000 55,000 217,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 22--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for P&R I Equipment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average
Total Total HAP cost HAP cost incremental
Total capital annualized annualized HAP emission effectiveness effectiveness HAP cost
Control option investment ($) costs w/o costs with reductions with credits w/o credits ($/ effectiveness
credits ($/yr) credits ($/yr) (tpy) ($/ton) ton) with credits
($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1....................................... 62,300 16,100 11,700 0.48 24,000 34,000 ..............
2....................................... 109,000 26,200 20,200 0.67 30,000 39,000 45,000
3....................................... 148,000 40,500 33,900 0.73 46,000 55,000 228,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 25140]]
Table 23--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for P&R II Equipment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average
Total Total HAP cost HAP cost incremental
Total capital annualized annualized HAP emission effectiveness effectiveness HAP cost
Control option investment ($) costs w/o costs with reductions with credits w/o credits ($/ effectiveness
credits ($/yr) credits ($/yr) (tpy) ($/ton) ton) with credits
($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1....................................... 16,400 4,300 3,200 0.13 25,000 33,000 ..............
2....................................... 28,700 7,000 5,400 0.18 30,000 39,000 44,000
3....................................... 39,400 10,700 8,900 0.19 47,000 56,000 350,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
b. NSPS Subpart VVa
This action presents the EPA's review of the requirements of 40 CFR
part 60, subpart VVa pursuant to CAA section 111(b)(1)(B). As described
in section II.G.2 of this preamble, the statutory review of these NSPS
focused on whether there are any emission reduction techniques that are
used in practice that achieve greater emission reductions than those
currently required by these NSPS and whether any of these developments
in practices have become the BSER. Based on this review, we have
determined that the BSER for reducing VOC emissions from equipment
leaks from SOCMI processes remain work practice standards based on
LDAR. However, we have 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.
We are proposing 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. The rationale for this
proposed action is presented in more detail below. Pursuant to CAA
section 111(a), the proposed NSPS included in this action would apply
to facilities that begin construction, reconstruction, or modification
after April 25, 2023 (see section III.F.2 of this preamble).
NSPS subpart VVa regulates equipment leaks from SOCMI affected
facilities whose construction, reconstruction, or modification
commenced after November 7, 2006. NSPS subpart VVa addresses fugitive
emissions of VOC from SOCMI affected facilities. Fugitive emissions are
emissions caused by leaks in processing equipment. NSPS subpart VVa
defines the affected facility as the ``group of all equipment within a
process unit,'' with equipment meaning ``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.'' In other words, the
affected facility is the collection of all the valves, pumps, etc.,
within a process unit. For the purpose of NSPS subpart VVa, the process
units are those components assembled to produce any of the chemicals
listed in 40 CFR 60.489a of subpart VVa. In promulgating NSPS subpart
VVa, the EPA determined that BSER is work practice standards for
equipment leaks based on LDAR and other control requirements. The
standards apply to connectors, compressors, PRDs, pumps, sampling
collection systems, OEL, and valves in VOC service. A piece of
equipment is in VOC service if it contains or contacts a fluid that is
at least 10 percent by weight or more of 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. These standards are generally the
same as those for HON equipment leaks, except the standards apply to
VOC instead of HAP, and the connector monitoring requirements in VVa
were stayed.\98\
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\98\ See 73 FR 31372, June 2, 2008.
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For our review of NSPS subpart VVa, we reviewed the RACT/BACT/LAER
clearinghouse database, and other EPA, state, and local regulatory
development efforts related to equipment leaks to determine advances in
process operations, design or efficiency improvements, or other systems
of emission reduction. The 2011 equipment leaks study (see section
III.C.6.a of the preamble) considered a 100 ppm leak definition, and we
identified at least one regulation, in the Bay Area Air Quality
Management District (BAAQMD), that requires gas and light liquid valves
to meet a 100 ppm leak definition. Additionally, in recent consent
decrees, the EPA has required low-emitting gas and light liquid valves
be used.\99\ Low-emitting valves use low emission packing in the valve
stem to reduce emissions below 100 ppm, but even these low-emitting
valves can eventually leak over time, as valve packing can deteriorate
as valves get used more and more. Discussions with valve manufacturers
have also shown that low-emitting valves are comparable in cost to
normal valves and are considered by at least one manufacturer to be the
valve standard commonly used by their customers. Because low-emitting
valves do not continually keep leaks below 100 ppm, the EPA did not
consider these valves as best system of emission reduction. Instead,
the EPA evaluated BSER based on LDAR at different leak definitions.
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\99\ https://www.epa.gov/sites/default/files/2013-09/documents/dowchemical-cd.pdf.
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We also evaluated the HON equipment leak requirements as many NSPS
process units are already complying with such requirements. The HON
equipment leak standards require monitoring connectors at a leak
definition of 500 ppm annually, with reduced monitoring frequency with
good performance. These are the same requirements as the stayed VVa
connector monitoring requirements.
Based on the information gathered from our review of NSPS subpart
VVa, we evaluated the following two control options. Option 1 was
lowering the leak definition for gas and light liquid valves from 500
ppm to 100 ppm. Option 2 was Option 1 plus adding connector monitoring
requirements from the stayed 2006 subpart VVa final rule, which is also
consistent with the current HON requirements.
For both options considered, we calculated the average costs and
cost effectiveness on an affected facility basis. Table 24 of this
preamble summarizes these average costs, cost-effectiveness, and
emissions reductions on an affected facility basis. For
[[Page 25141]]
additional details, see the document titled CAA 111(b)(1)(B) review for
the SOCMI Equipment Leaks NSPS Subpart VVa which is available in the
docket for this rulemaking.
Table 24--Average Cost and Environmental Impacts for Equipment Leak Options per Affected Facility
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total annual Cost-effectiveness w/recovery
Total capital Total annual cost w/ VOC emission credits ($/ton VOC)
Control option investment ($) cost ($/yr) recovery reductions -------------------------------
credits ($/yr) (tpy) Average Incremental
--------------------------------------------------------------------------------------------------------------------------------------------------------
Option 1: Gas and LL valve monitoring monthly at a leak 10,100 2,360 1,780 0.64 2,780 N/A
definition of 100 ppm, with skip periods \1\...........
Option 2: Option 1 plus connector monitoring annually at 208,300 38,800 30,500 9 3,390 3,400
a leak definition of 500 ppm, with skip periods........
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Skip periods refers to reduced monitoring frequency, i.e., skipping monitoring during some periods due to good performance.
We are proposing to determine Option 2 to be cost-effective for
new, modified, and reconstructed sources. Many SOCMI facilities are
already complying with these requirements. Based on the results of our
analysis, we are proposing BSER for NSPS subpart VVb to be NSPS subpart
VVa plus revising the equipment leak standards in a new subpart VVb to
lower the leak definition for gas and light liquid valves from 500 ppm
to 100 ppm and include requirements for connectors consistent with the
HON requirements.
We conducted an analysis to estimate how many affected facilities
are expected/projected to be subject to the proposed equipment leak
requirements presented above. An affected facility can become subject
to NSPS subpart VVb under one of the following scenarios: (1) The
affected facility is at a new greenfield facility; (2) the affected
facility is a new affected facility at an existing plant site; (3) an
existing affected facility is modified; or (4) an existing affected
facility triggers the reconstruction requirements. For scenario 1
(i.e., affected facility is at a new greenfield facility), we assumed
only one greenfield facility, with two process units, will trigger NSPS
subpart VVb over the next 5 years. We used facility responses to our
CAA section 114 request to help us determine the number of facilities
that could potentially trigger scenarios 2, 3, and 4.
For scenario 2 (i.e., new affected facilities constructed at
existing plant sites), we assessed information from facilities
responding to the EPA's CAA section 114 request. The responses to the
CAA section 114 request showed 34 affected facilities subject to NSPS
subparts VV or VVa. One of the affected facilities was a new
construction in the last 5 years. The OECA's ECHO tool (https://echo.epa.gov) indicates there are currently 592 SOCMI facilities
subject to subpart VV or VVa. We assumed an average of two affected
facilities per plant site. Assuming the same distribution of new
construction, 34 new affected facilities would have been constructed in
the last 5 years for all SOCMI facilities. The analysis assumes that
the same number of affected facilities that were constructed in the
last 5 years would be constructed in the next 5 years.
For scenario 3 (i.e., existing facility is modified) and scenario 4
(i.e., existing facility triggers reconstruction requirements),
facilities responding to the EPA's CAA section 114 request did not
report any modified or reconstructed facilities in the last 5 years or
in the last 10 years. Eight of the 34 affected facilities discussed in
scenario 2 indicated either modification or reconstruction since their
construction, ranging back to the 1940's. We assumed the eight affected
facilities were modifications because the reconstruction requirements
are less likely to be triggered. For scenario 3 we assumed that at
least one affected facility would be modified in the next 5 years,
likely by addition of new unit operations that would increase the
number of components. We also assumed that no affected facilities will
trigger the reconstruction requirements in scenario 4.
Table 25 of this preamble presents the nationwide impacts for the
Option 2. See the document titled CAA 111(b)(1)(B) review for the SOCMI
Equipment Leaks NSPS Subpart VVa, which is available in the docket for
this rulemaking, for details on the assumptions and methodologies used
in this analysis. We are proposing that affected facilities that are
constructed, reconstructed, or modified after April 25, 2023 would be
subject to these proposed requirements in NSPS subpart VVb. We solicit
comment on all of the proposed requirements related to standards for
equipment leaks in new NSPS subpart VVb.
Table 25--Nationwide Emissions Reductions and Cost Impacts of Control Options Considered for Affected Facilities
Triggering NSPS Subpart VVb
----------------------------------------------------------------------------------------------------------------
Cost-
Total annual VOC emission effectiveness
Scenario Total capital Total annual cost w/ reductions w/recovery
investment ($) cost ($/yr) recovery (tpy) credits ($/ton
credits ($/yr) VOC)
----------------------------------------------------------------------------------------------------------------
Scenario 1 (i.e., two affected 416,600 77,500 60,900 18 3,380
facilities at a new greenfield
facility)......................
Scenario 2 (i.e., 34 new 7,081,700 1,317,900 1,035,800 313 3,310
affected facilities)...........
Scenarios 3 and (i.e., one 208,300 38,800 30,500 9 3,390
modified existing affected
facility)......................
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[[Page 25142]]
Total....................... 7,706,600 1,434,200 1,127,200 340 3,320
----------------------------------------------------------------------------------------------------------------
7. Standards for Fenceline Monitoring
Fenceline monitoring refers to the placement of monitors along the
perimeter of a facility to measure pollutant concentrations. Coupled
with requirements for root cause analysis and corrective action upon
triggering an actionable level, this work practice standard is a
development in practices considered under CAA section 112(d)(6) for the
purposes of managing fugitive emissions. The measurement of these
pollutant concentrations and comparison to concentrations estimated
from mass emissions via dispersion modeling is used to ground-truth
emission estimates from a facility's emissions inventory. If
concentrations at the fenceline are greater than expected, the likely
cause is that there are underreported or unknown emission sources
affecting the monitors. In addition to the direct indication that
emissions may be higher than inventories would suggest, fenceline
monitoring provides information on the location of potential emissions
sources because it provides complete spatial coverage of a facility.
Further, when used with a mitigation strategy, such as root cause
analysis and corrective action upon exceedance of an action level,
fenceline monitoring can be effective in reducing emissions and
reducing the uncertainty associated with emissions estimation and
characterization. Finally, public reporting of fenceline monitoring
data provides public transparency and greater visibility, leading to
more focus and effort in reducing emissions. Fenceline monitoring has
not yet been required or considered in prior rulemaking actions or
regulations governing SOCMI, P&R I or P&R II HAP emissions, but has
been required for Petroleum Refineries in 40 CFR part 63, subpart CC
(see 40 CFR 63.658). As such we evaluated the application of fenceline
monitoring as a development in practices, processes, and control
technologies pursuant to CAA section 112(d)(6). As further explained
below, our evaluation only focuses on HON and P&R I facilities that
use, produce, store, or emit benzene, 1,3-butadiene, chloroprene,
ethylene dichloride, EtO, or vinyl chloride.
Fenceline monitoring has been successfully applied to the petroleum
refineries source category as a technique to manage and reduce benzene
emissions from fugitive emissions sources such as storage vessels,
wastewater treatment systems, and leaking equipment. In 2015, the EPA
promulgated the RTR for the petroleum refineries source category and
required that refineries install and operate fenceline monitors
following EPA Reference Method 325 A/B to monitor benzene emissions.
The 2015 rule (80 FR 75178) required that refineries install and begin
operating passive diffusive tube monitors by 2018 and report benzene
emissions monitoring data to the EPA beginning in 2019.\100\
Additionally, the 2015 rule required that refineries conduct a root
cause analysis to identify sources of high fenceline monitoring
readings (i.e., above an annual action level) and then develop a
corrective action plan to address the sources and reduce emissions to a
level that will bring fenceline monitoring concentrations below the
action level.\101\ To date, the EPA has received fenceline monitoring
data for more than four years.\102\ These data show that petroleum
refinery fenceline concentrations have dropped by an average of 30
percent since the inception of the monitoring program requirements.
These results illustrate that fenceline monitoring is an effective tool
in reducing emissions and preserving emission reductions on an ongoing
basis for these sources.
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\100\ See 40 CFR 63.658(a) and 40 CFR 63.655(h)(8).
\101\ 40 CFR 63.658(f)-(h).
\102\ Quarterly fenceline monitoring reports are available
through the EPA's WebFIRE database at https://cfpub.epa.gov/webfire/. The EPA has also developed a dashboard to improve public
access to this data. The dashboard is available at https://awsedap.epa.gov/public/extensions/Fenceline_Monitoring/Fenceline_Monitoring.html?sheet=MonitoringDashboard.
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The majority of emissions from sources covered by the HON and P&R I
are fugitive in nature and are often difficult to characterize and
quantify. In order to assess the effect of emissions for purposes of
risk characterization, we rely on the assumption that reported
emissions are accurate. Thus, if the reported inventories are accurate,
all facilities should be able to meet the fenceline concentration
action levels considering the controls we are proposing. Further,
fenceline monitoring provides the facility and the EPA with an
understanding of where the concentrations of toxic HAP exceed expected
concentrations and provide a path for owners and operators to further
identify the root causes of such exceedances and to mitigate emissions
from these sources. For facilities regulated by the HON or P&R I, the
EPA identified six specific HAP that we determined were the most
appropriate, useful, and suitable for inclusion on the fenceline
monitoring program. These compounds were identified as cancer risk
drivers in the prior RTRs for the HON and P&R I conducted in 2006 (HON)
and 2008 and 2011 (P&R I) or identified as cancer risk drivers in the
residual risk reviews proposed in this action, and each is emitted
(largely as fugitive emissions) from processes at HON and P&R I
sources.\103\ As part of our CAA section 114 request, we also collected
fenceline monitoring data for these compounds at various facilities and
often found them to be present in concentrations that were higher than
our modeling of reported emissions inventories would predict.\104\
Although the model to monitor averages are not quantitatively
comparable because they are based on different time periods (i.e., an
annual average versus 7 sampling periods), the monitored concentrations
typically exceeded concentrations established by the modeling; in some
cases, by multiple orders of magnitude. This is an indicator that
reported emissions may be underestimated. Therefore, in this action,
the EPA is proposing at 40 CFR 63.184 to implement a fenceline
monitoring
[[Page 25143]]
program under CAA section 112(d)(6) to limit fugitive emissions. We are
proposing 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. A brief summary of the proposed fenceline sampling
requirements and our rationale for selecting the corrective action
concentration levels are provided below. We solicit comment on the
proposed standards for fenceline monitoring.
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\103\ P&R II sources do not emit any of these six pollutants.
\104\ See model to monitor comparison in the document entitled
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, which is available in the docket for this rulemaking.
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Developments in monitoring technology and practices. The EPA
reviewed the available literature and identified two different methods
for monitoring fugitive emissions of benzene, 1,3-butadiene,
chloroprene, ethylene dichloride, EtO, and vinyl chloride around a
chemical facility. These methods include: (1) Passive diffusive tube
monitoring networks for the measurement of benzene, 1,3-butadiene,
chloroprene, and ethylene dichloride; and (2) Canister monitoring
networks for the measurement of EtO and vinyl chloride. We considered
these monitoring methods as developments in practices under CAA section
112(d)(6) for purposes of managing fugitive emission sources at
chemical manufacturing facilities.
Fenceline passive diffusive tube monitoring networks employ a
series of diffusive tube samplers at set intervals along the fenceline
to measure a time-integrated \105\ ambient air concentration at each
sampling location. A diffusive tube sampler consists of a small tube
filled with an adsorbent, selected based on the pollutant(s) of
interest, and capped with a specially designed cover with small holes
that allow ambient air to diffuse into the tube at a small, fixed rate.
Diffusive tube samplers have been demonstrated to be a cost-effective,
accurate technique for measuring concentrations of pollutants (e.g.,
benzene) resulting from fugitive emissions in a number of studies
106 107 as well as in the petroleum refining sector.\108\ In
addition, diffusive samplers are used in the European Union to monitor
and maintain air quality, as described in European Union directives
2008/50/EC and Measurement Standard EN 14662-4:2005 for benzene. The
International Organization for Standardization developed a standard
method for diffusive sampling (ISO/FDIS 16017-2). In recent years, the
EPA has expanded the use of diffusive sorbent tubes through our CAA
Section 114 authority to evaluate fenceline concentrations of HAP in
addition to benzene, such as chloroprene and 1,3-butadiene. To support
these efforts, the EPA used existing uptake rates included in EPA
Methods 325A/B at 40 CFR part 63, Appendix A, and when necessary,
developed new uptake rates.\109\ Therefore, the EPA is proposing to
require fenceline monitoring of benzene, chloroprene, 1,3-butadiene,
and ethylene dichloride measured with 14-day sampling periods using
diffusive tube samplers in accordance with EPA Methods 325A/B at 40 CFR
part 63, Appendix A. The EPA notes that based on recent studies, we
will be incorporating new sorbents and revised uptake rates for certain
pollutants in an upcoming revision to EPA Method 325B.\110\
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\105\ Time-integrated sampling refers to the collection of a
sample at a controlled rate. The sample provides an average
concentration over the sample period. For the diffusive tube
samplers, the controlled rate of sampling is dictated by the uptake
rate. The uptake rate is the amount of a compound that can be
absorbed by a particular sorbent over time during the sampling
period.
\106\ McKay, J., M. Molyneux, G. Pizzella, V. Radojcic.
Environmental Levels of Benzene at the Boundaries of Three European
Refineries, prepared by the CONCAWE Air Quality Management Group's
Special Task Force on Benzene Monitoring at Refinery Fenceline (AQ/
STF-45), Brussels, June 1999.
\107\ Thoma, E.D., M.C. Miller, K.C. Chung, N.L. Parsons, B.C.
Shine. 2011. Facility Fenceline Monitoring using Passive Samplers,
J. Air & Waste Manage Assoc. 61: 834-842.
\108\ See EPA-HQ-OAR-2010-0682; fenceline concentration data
collected for the petroleum refining sector rulemaking can be
accessed via the Benzene Fenceline Monitoring Dashboard at https://awsedap.epa.gov/public/extensions/Fenceline_Monitoring/Fenceline_Monitoring.html?sheet=MonitoringDashboard.
\109\ Docket Reference to ``Method 325B Addendum A, Evaluation
of Chloroprene Uptake Rate Report.''
\110\ Markes International Ltd. Uptake Rate Tests: Tests for a
range of compounds onto four sorbent types over periods of 1 and 2
weeks. September 27, 2022.
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In this action, the EPA is proposing a new EPA reference method to
monitor the concentration of EtO and vinyl chloride from facility
fenceline locations, EPA Method 327 to 40 CFR part 63, Appendix A. EPA
Method 327 is a canister sampling and analysis method that provides
procedures for measuring trace levels of targeted VOC (including
organic HAP) in ambient air. It draws upon the guidance in Method TO-
15A \111\ for canister sampling and further develops this guidance into
a robust method specific for fenceline monitoring, defining required
data quality objectives, and incorporating existing best practices into
the method. In EPA Method 327, ambient air samples are collected using
specially prepared and pre-cleaned evacuated stainless-steel canisters.
For analysis, a known volume of air is directed from the canister to a
pre-concentrator, and the targeted VOC from the sample are measured
using a gas chromatograph-mass spectrometer (GC-MS). The EPA is
proposing to require fenceline monitoring of EtO and vinyl chloride
with 24-hour sampling periods once every 5 days using canister sampling
in accordance with EPA Method 327 at 40 CFR part 63, appendix A. This
monitoring frequency is necessary to ensure that all onsite processes
are monitored regularly and approaches the time-integrated sampling of
EPA Methods 325A/B, while still maintaining the cost effectiveness of
implementing a canister monitoring network. A sampling frequency of
every five days will also help to reduce the possibility of only
monitoring emission spikes such that the annual average concentration
is indicative of the actual average emissions from the site.
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\111\ https://www.epa.gov/sites/default/files/2019-12/documents/to-15a_vocs.pdf.
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The EPA considered requiring EPA Method 327 for monitoring ethylene
dichloride, because ethylene dichloride is almost always going to be
monitored alongside vinyl chloride. Because vinyl chloride is monitored
with EPA Method 327, monitoring ethylene dichloride with EPA Method 327
would simplify the monitoring and increase the cost effectiveness of
implementing the fenceline monitoring program. However, in this action
EPA has chosen to require EPA Methods 325A/B for monitoring ethylene
dichloride because based on the available data, at least one vinyl
chloride monomer facility reported emissions of chloroprene, which
would require that facility to monitor for chloroprene with EPA Methods
325A/B. Because monitoring with EPA Methods 325A/B is more continuous
than with EPA Method 327 and the results with EPA Methods 325A/B
generally have less variability, monitoring with EPA Methods 325A/B is
the preferred approach. We are however soliciting comment on whether we
should allow the use of EPA Method 327 for monitoring fenceline
concentration of ethylene dichloride for sites that have to monitor
fenceline concentrations of vinyl chloride but do not have to monitor
fenceline concentrations of chloroprene, benzene, or 1,3-butadiene.
While EPA Method 327 is based on Method TO-15A, there are notable
differences between the two methods. EPA Method 327 addresses some of
the challenges encountered while performing sampling and analysis of
EtO with Method TO-15A by incorporating best practices into the method.
EPA Method 327 also is written
[[Page 25144]]
to mandate actions within the method as opposed to providing guidance
on how the method should be performed. The major differences between
Method TO-15A and Method 327 include the following, but are not limited
to:
Updated sample cleanliness requirements and removal of the
option for glass bottles and non-rigid containers.
invalidation of samples that do not meet initial and final
canister pressure requirements.
requirement to examine chromatograms for potential
interferences, with a strong recommendation for the use of full scan
ion spectra MS mode during analysis.
requirements for certification and recertification of
standards to ensure the quality and stability of the standards.
requirements for one field blank and one field duplicate
for each sampling period.
requirement for the field blank diluent gas to be
humidified zero air.
maximum allowed sample holding time of 7 days.
requirement to drift correct measured values based on
continuous calibration verification criteria according to the
procedures in EPA Method 325B.
To achieve the lowest possible detection limits with canister
sampling, the EPA has determined that it is necessary to mandate these
best practices within EPA Method 327. Although facilities were asked to
follow these best practices in the CAA section 114 request, the data
submitted in response to the request indicated there are sampling and
analysis issues that still need to be addressed, especially in regard
to measuring EtO.
While the EPA acknowledges that there are some drawbacks of time-
integrated sampling, including the lack of immediate feedback on the
acquired data and the loss of short-term temporal information, our
experience with the fenceline monitoring program in the petroleum
refining sector has proven that these systems are capable of achieving
meaningful emissions reductions by allowing earlier detection of
significant fugitive emissions than conventional source-specific
monitoring, such as through a periodic leak detection program with EPA
Method 21 of 40 CFR part 60, appendix A-7. Additionally, time-
integrated monitoring systems are generally lower-cost and require less
labor than time-resolved \112\ monitoring systems; they generally have
lower detection capabilities as well. Time-resolved monitoring stations
have been used for a variety of pollutants in a variety of settings and
the methods are well-established. However, compared to the passive
diffusive tube monitoring stations or canister sampling, time-resolved
monitoring stations are more expensive, more labor-intensive, and
generally require highly-trained staff to operate. The EPA acknowledges
the state of technology is advancing and that the capabilities of these
systems will continue to improve and that the costs will likely
decrease. Therefore, we are providing a pathway for an owner or
operator to request use of other types of monitoring networks to
demonstrate compliance with the fenceline standards through a request
for an alternative test method under the provisions of 40 CFR 63.7(f).
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\112\ Time resolved monitoring involves sampling within short
timeframes (generally on the magnitude of minutes to hours) in order
to see the variation in concentration of a compound in near real
time.
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Siting, design, and sampling requirements for fenceline monitors.
The EPA is proposing that fenceline monitors be deployed to measure
fenceline concentrations of benzene, 1,3-butadiene, chloroprene,
ethylene dichloride, EtO, and vinyl chloride at chemical manufacturing
facilities subject to the HON or P&R I. A primary requirement for a
fenceline monitoring system is that it provides adequate spatial
coverage for determination of representative pollutant concentrations
at the boundary of the facility. In an ideal scenario, fenceline
monitors would be placed so that any fugitive plume originating within
the facility would have a high probability of intersecting one or more
monitors, regardless of wind direction. Therefore, we are proposing
that for passive diffuse tube monitoring of benzene, 1,3-butadiene,
chloroprene, and ethylene dichloride, facilities determine the
appropriate number and location of fenceline sampling monitors using
the siting method requirements described in EPA Method 325A of 40 CFR
part 63, Appendix A. Sample collection and analysis of the passive
tubes would be performed according to EPA Methods 325A and 325B of 40
CFR part 63, appendix A.
For canister monitoring of EtO and vinyl chloride, the EPA is
proposing that each facility would place 8 canisters evenly spaced on
the monitoring perimeter. The monitoring perimeter may be the facility
fenceline or may be inside the facility fenceline as long as all
sources of the monitored compound(s) are contained within the
perimeter. Because we recognize that the spatial coverage provided by
this arrangement is less than that provided under EPA Method 325A, the
EPA is also proposing that facilities would be required to move the
canister sampling locations with alternating sampling periods in order
to ensure complete spatial coverage of the facility. For facilities
with emission sources of monitored pollutants that are not contained
within one contiguous area, the EPA is proposing that these secondary
areas would be monitored as well, with the number of canisters on the
secondary area dictated by the size of the area. The proposed
requirements for siting the canisters are described in NESHAP subpart H
(see proposed 40 CFR 63.184). While we recognize that EPA Method 325A
contains an option for siting passive tubes by determining the
geographic center of the facility and spacing the tubes based on
measured angles from the center point, the EPA has chosen not to
provide a similar approach for the canisters in order to simplify the
siting of the canisters. We request comment on the proposed approach
for siting the canisters and whether we should provide an alternative
siting approach based on measured angles from the center point.
For each sampling period (2-week period for passive tubes or 24-
hour period for canisters), the facility would determine a delta c,
calculated as the lowest sample value for the compound of interest
subtracted from the highest sample value for the compound of interest.
This approach is intended to subtract out the estimated contribution
from background emissions that do not originate from the facility. The
delta c for the most recent year of samples (26 sampling periods for
passive tubes and 73 sampling periods for canisters) would be averaged
to calculate an annual average delta c. The annual average delta c
would be determined on a rolling basis, meaning that it is updated with
every new sample (i.e., for passive tubes, every 2 weeks a new annual
average delta c is determined from the most recent 26 sampling periods
and for canisters, every 5 days a new annual average delta c is
determined from the most recent 73 sampling periods). This rolling
annual average delta c would be calculated for each compound of
interest and compared against a concentration action level for each
pollutant.
Action levels and rationale. As mentioned above, the EPA is
proposing to require facilities subject to the HON and P&R I to take
corrective action to reduce fugitive emissions if monitored fenceline
concentrations exceed a specific concentration action level on a
[[Page 25145]]
rolling annual average basis.\113\ For benzene, 1,3-butadiene, ethylene
dichloride, and vinyl chloride, we selected the proposed fenceline
action levels by modeling fenceline HAP concentrations using the
emissions inventories used in the residual risk assessment of the
facility-wide review of the SOCMI source category and Neoprene
Production source category (e.g., 2017 NEI), assuming that those
reported emissions represented full compliance with all proposed HON or
P&R I requirements, adjusted for additional control requirements we are
proposing in this action.\114\ We estimated the long-term fenceline
post-control HAP concentrations at each facility using the post-control
facility-wide emissions inventory and the EPA's HEM. Concentrations
were estimated by the model at a set of polar grid receptors centered
on each facility, as well as surrounding census block centroid
receptors extending from the facility outward to 50 km (~31 miles). For
purposes of this modeling analysis, we assumed that the nearest off-
site polar grid receptor was the best representation of each facility's
fenceline concentration in the post-control case, unless there was a
census block centroid nearer to the fenceline than the nearest off-site
polar grid receptor or an actual receptor was identified from review of
the site map. In those instances, we estimated the fenceline
concentration as the concentration at the census block centroid. Only
receptors (either the polar or census block) that were estimated to be
outside the facility fenceline were considered in determining the
maximum HAP concentration level for each facility. After modeling each
facility, we then selected the maximum annual average benzene, 1,3-
butadiene, ethylene dichloride, and vinyl chloride fenceline
concentration modeled at any facility as the action level for that HAP.
Thus, if the reported inventories are accurate, all facilities should
be able to meet the fenceline concentration action levels. We note that
this analysis does not correlate to any particular metric related to
risk. The maximum annual average HAP concentrations modeled at the
fenceline for any facility, rounded to one significant figure, were 9
micrograms per cubic meter ([mu]g/m\3\, benzene),\115\ 3 [mu]g/m\3\
(1,3-butadiene), 4 [mu]g/m\3\ (ethylene dichloride), and 3 [mu]g/m\3\
(vinyl chloride). Therefore, the EPA is proposing these fenceline
concentrations as action levels for these four HAP.
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\113\ Calculated every two weeks for benzene, 1,3-butadiene,
ethylene dichloride, and chloroprene. Calculated every five days for
ethylene oxide and vinyl chloride.
\114\ We note that 10 of the 19 facilities with P&R I processes
also have HON processes.
\115\ Since we are considering facility-wide emissions, an
action level of 9 [mu]g/m\3\ was chosen for benzene since the
refinery who set the action level in 2015 for that source category
is also a HON facility.
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Due to current limitations in method detection limits for EtO and
chloroprene, and the concerns for cancer risk driven by these two
pollutants, we selected the proposed fenceline action levels to be
equal to three times the representative detection limit (RDL) for these
two pollutants, as this is the minimum concentration that can be
measured with reasonable certainty. The RDL is based on the results of
the best performing testing companies and laboratories using the most
sensitive analytical procedures. A multiplication factor of three is
used to reduce the imprecision of the method until the imprecision in
the sampling and analysis is similar to the precision of other EPA
methods. The RDL for chloroprene was determined to be 0.09 [mu]g/m\3\,
and the RDL for EtO was determined to be 0.07 [mu]g/m\3\. Therefore,
the EPA is proposing action levels of 0.3 [mu]g/m\3\ for chloroprene
and 0.2 [mu]g/m\3\ for EtO. We acknowledge that these proposed
concentrations are lower than the fenceline modeled concentrations for
EtO and chloroprene from facilities in the SOCMI and Neoprene
Production source categories after implementation of our proposed
standards; 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 set the action levels
of chloroprene and EtO at facility boundaries as low as possible
(considering method detection limitations) to ensure emission
reductions anticipated from implementation of controls used to meet the
proposed standards and to achieve additional HAP emission reductions.
Though we have not proposed to prescribe additional specific controls
to the existing inventories because remaining emissions are fugitive in
nature and less certain in terms of frequency of events and
characterization of emissions, there are still measures that are likely
available that could be employed to address emission sources in a more
directed manner. For example, identifying and reducing emissions from
sources such as maintenance events that could not be accounted for in
the post control modeling exercise would be effective in achieving
additional emission reductions. In addition to proposing this fenceline
monitoring work practice standard under CAA section 112(d)(6)
reflecting developments in practices, processes, and control
technologies, we also request comment on whether it would be
appropriate, in the final rulemaking, to promulgate these proposed
fenceline monitoring work practice standards, including the proposed
fenceline 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. Making such
a determination might be warranted, for example, in light of the fact
that we considered the facility-wide risk as an additional factor not
considered in the source category-specific risk acceptability decisions
for the SOCMI and Neoprene Production source categories that are both
the subject of this single combined rulemaking action.
For further details of the analysis, 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, which is
available in the docket for this rulemaking.
Non-source category emissions. This proposed approach also
considers the possibility that offsite sources could contribute to
modeled concentrations at a facility's fenceline. Additionally, non-HON
and non-P&R I sources could be located within facility property
boundaries that also contribute to monitor readings. In this proposal,
we are allowing the subtraction of offsite interfering sources (as they
are not within the control of the owner or operator) through site
specific monitoring plans, but we are not providing this option for
onsite, non-source category emissions. The action levels above were
based on facility-wide emissions, and therefore these non-source
category sources have been considered in their development. Applying
the fenceline standard to the whole facility will also limit emissions
of toxic HAP from all sources and provide more certainty in decisions
being made on whether the entire facility emissions align with what is
expected from the EPA's analysis. It will also provide assurances to
fenceline communities that emission reductions are achieved and
maintained. This is important in the chemical sector, where there could
be numerous source
[[Page 25146]]
categories that can be collocated within a larger facility, and have
common tank farms, wastewater systems, heat exchangers, APCDs, fuel gas
systems, etc., that may be assigned or apportioned to various source
categories.
Corrective action requirements. The proposed fenceline monitoring
provisions would require the initiation of root cause analysis upon
exceeding the annual average concentration as determined on a rolling
average every sampling period. The root cause analysis is an assessment
conducted through a process of investigation to determine the primary
underlying cause and other contributing causes of an exceedance of the
action level. The root cause analysis would be required to be initiated
within 5 days of determining that an updated annual average
concentration of a target pollutant exceeds the applicable action
level. A root cause analysis must be conducted following each 14-day
sampling period in which the annual average concentration(s) remain
above the action level to determine whether the monitoring results and
associated data indicate additional sources of emissions contributing
to concentrations remaining above the action level. If the owner or
operator cannot determine the root cause of the exceedance within 30
days of determining there was an exceedance of an action level, the
owner or operator would be required to use real-time sampling
techniques (e.g., mobile gas chromatographs) to determine the root
cause of the exceedance.
If the underlying causes of the action level exceedance are deemed
to be from sources under the control of the owner or operator, the
owner or operator would be required to take corrective action to
address the underlying cause of the exceedance and to bring
concentrations back below the action level as expeditiously as
possible. Completion of the root cause analysis and initial corrective
action would be required within 45 days of determining that there was
an exceedance of an action level. If the owner or operator requires
longer than 45 days to implement the corrective actions identified by
the root cause analysis, the owner or operator would be required to
submit a corrective action plan no later than 60 days after completion
of the root cause analysis.
After completion of the initial corrective action, if the delta c
for the next sampling period for samples collected by EPA Methods 325A/
B or the next three sampling periods for samples collected by EPA
Method 327 \116\ are below the action level, then the corrective action
is assumed to have fixed the problem, and the owner and/or operator
would have no further obligation for additional corrective action.
However, if the delta c for the subsequent sampling periods after
initial corrective action is over the action level, then the owner or
operator would have to submit a corrective action plan and schedule for
implementing design, operation, and maintenance changes to eliminate as
quickly as possible and prevent recurrence of the primary cause and
other contributing causes to the exceedance of the action level in
order to reduce annual average concentrations below the action level.
The owner or operator would be required to include the implementation
of real-time sampling techniques to locate the primary and other
contributing causes of the exceedance in the corrective action plan.
While the action level(s) are based on annual average concentrations,
once an action level is exceeded, each sampling period that exceeds the
action level contributes to the delta c remaining above the action
level. An investigation must be conducted following these high biweekly
periods to determine the root cause and, if appropriate, to correct the
root cause expeditiously in order to bring the annual average delta c
below the action level.
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\116\ The EPA is proposing that three sample periods must remain
below the action level for samples taken by EPA Method 327 because
three is equal to the number of samples that would be taken during
one sample period for EPA Methods 325A/B. Requiring three sample
periods also ensures that a sample will have been taken at every
monitoring location at the site following the completion of the
corrective action.
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Costs associated with fenceline monitoring requirements. We
estimated costs to monitor for benzene, 1,3-butadiene, chloroprene, and
ethylene dichloride at the fenceline using final rule costs for passive
diffusive tube monitoring using the medium model plant costs for the
2015 Petroleum Refinery Sector final rule (80 FR 75178, December 1,
2015) and scaled costs to 2021 dollars. For EtO and vinyl chloride, we
estimated fenceline monitoring costs for 8 summa cannisters around the
fenceline every 5 days. We also note that there a number of HON
facilities that are either collocated with refineries who are already
conducting passive diffusion tube fenceline monitoring for benzene as
well as some HON facilities under consent decree conducting fenceline
monitoring for benzene with passive diffusion tubes, so costs to add
laboratory analysis for a second analyte under this action are minimal
(i.e., $1,300 more per year) for these facilities, and why monitoring
scenario 2 in the table below for the HON is less costly than
monitoring scenario 1 even though more facilities fall into the
monitoring scenario 2 category. In total for this proposed rulemaking
package, we estimate nationwide impacts for fenceline monitoring to be
$9,881,000 for total capital investment and $33,310,000 per year for
total annualized cost, and estimate that 126 of the 207 HON facilities
and 12 of the 19 P&R I facilities would be required to conduct
fenceline monitoring as they emit at least one of the six HAP of
interest. Tables 26 and 27 provide the breakdown of estimated
nationwide costs for fenceline monitoring as applied to all HON and P&R
I sources. Note that ten facilities have collocated sources subject to
multiple NESHAP (i.e., the HON and P&R I) and would be required to
conduct fenceline monitoring under both rules, therefore where this
occurred, we assigned costs and included the facility under the SOCMI
source category for impacts to avoid double counting. For further
information, see the document titled Clean Air Act Section 112(d)(6)
Technology Review for Fenceline Monitoring located in the SOCMI Source
Category that are Associated with Processes Subject to HON and for
Fenceline Monitoring that are Associated with Processes Subject to
Group I Polymers and Resins NESHAP, which is available in the docket
for this rulemaking.
[[Page 25147]]
Table 26--Nationwide Cost Impacts of Fenceline Monitoring for HON
----------------------------------------------------------------------------------------------------------------
Total
Number Monitoring option Total capital annualized
Monitoring scenario facilities description investment ($) costs (million
impacted $/yr)
----------------------------------------------------------------------------------------------------------------
1.................................. 35 Passives only (1 analyte).. 4,016,000 2,141,000
2.................................. 46 Passives only (2 analytes). 2,295,000 1,282,000
3.................................. 9 Cannisters only............ 115,500 5,366,000
4.................................. 16 Cannisters and passives (1 1,606,000 10,397,000
analyte).
5.................................. 20 Cannisters and passives (2 1,721,000 12,869,000
analytes).
----------------------------------------------------------------------------------------------------------------
Table 27--Nationwide Cost Impacts of Fenceline Monitoring for P&R I
----------------------------------------------------------------------------------------------------------------
Number Total
Monitoring scenario facilities Monitoring option Total capital annualized
impacted description investment ($) costs ($/yr)
----------------------------------------------------------------------------------------------------------------
1.................................. 1 Cannisters and passives (2 114,700 659,000
analytes).
2.................................. 1 Cannisters only............ 12,800 596,000
----------------------------------------------------------------------------------------------------------------
Additional requirements of the fenceline monitoring program. The
EPA is proposing at 40 CFR 63.182(e) that fenceline data be reported on
a quarterly basis. Each report would contain the results for each
sample where the field portion of sampling is completed by the end of
the quarter, as well as for associated field and method blanks (i.e.,
each report would contain data for at least 6, 2-week sampling periods
and 18 canister sampling periods). These data would be reported
electronically to the EPA within 45 days of the end of each quarterly
period. See section III.E.3 of this preamble for further discussion on
electronic reporting and section III.F.1 of this preamble for further
discussion on the compliance dates we are proposing.
D. What actions related to CAA section 112(d)(2) and (3) are we taking
in addition to those identified in the CAA sections 112(f)(2) and
(d)(6) risk and technology reviews and CAA section 111(b)(1)(B) NSPS
reviews?
In addition to the proposed actions discussed in this section III.B
of this preamble to reduce risk from EtO emission sources (from HON
processes) and chloroprene emission sources (from P&R I affected
sources producing neoprene), and our proposed actions discussed in this
section III.C of this preamble on NESHAP technology reviews, we are
also proposing other requirements for the HON, P&R I, and P&R II based
on analyses performed pursuant to CAA section 112(d)(2) and (3),\117\
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.
We are proposing to: (1) Add new monitoring and operational
requirements for HON and P&R I flares, (2) add 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), (3) clarify regulatory provisions for vent control bypasses
for certain HON and P&R I vent streams (i.e., closed vent systems
containing bypass lines), (4) add dioxins and furans emission limits to
the HON, P&R I, and P&R II, (5) add new monitoring requirements for HON
and P&R I pressure vessels, (6) add new emission standards for HON &
P&R I surge control vessels and bottoms receivers, (7) revise the
applicability threshold for HON transfer racks, (8) add requirements to
P&R II for heat exchange systems, and (9) add requirements to P&R II
for WSR sources and equipment leaks. See the subsections below for
specific details regarding these proposed actions, and for which rules
(i.e., HON, P&R I, and/or P&R II) we are proposing these actions.
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\117\ The EPA has authority under CAA section 112(d)(2) and (3)
to set MACT standards for previously unregulated emission points.
The EPA also retains the discretion to revise a MACT standard under
the authority of CAA section 112(d)(2) and (3) (see Portland Cement
Ass'n v. EPA, 665 F.3d 177, 189 (D.C. Cir. 2011)), such as when it
identifies an error in the original standard. See also Medical Waste
Inst. v. EPA, 645 F.3d 420, 426 (D.C. Cir. 2011) (upholding the EPA
action establishing MACT floors, based on post-compliance data, when
originally-established floors were improperly established).
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1. Flares
The EPA is proposing under CAA section 112(d)(2) and (3) to amend
the operating and monitoring requirements for flares used as APCDs in
the SOCMI and P&R I source categories because we have determined that
the current requirements for flares are not adequate to ensure the
level of destruction efficiency needed to conform with the MACT
standards in the HON and P&R I.\118\ As previously mentioned in section
III.C.3.b of this preamble, we are also proposing these same operating
and monitoring requirements for flares for NSPS subparts IIIa, NNNa,
and RRRa under CAA section 111(b)(1)(B). Flares are commonly used
within the SOCMI and P&R I source categories. The requirements
applicable to flares, which are used to control emissions from various
emission sources (e.g., process vents, storage vessels, transfer racks,
equipment leaks, wastewater streams), are set forth in the General
Provisions to 40 CFR part 63 and are cross-referenced in the HON and
P&R I. In general, flares used as APCDs are expected to achieve 98
percent HAP destruction efficiencies when designed and operated
according to the requirements in the General Provisions. Studies on
flare performance,\119\ however, indicate that these General Provision
requirements are inadequate to ensure proper performance of flares at
refineries and other petrochemical facilities (including SOCMI
facilities), particularly when either assist steam or assist air is
used. In addition, over the last decade, flare minimization efforts at
these facilities have led to an increasing number of flares operating
at well below their
[[Page 25148]]
design capacity, and while these efforts have resulted in reduced
flaring of gases, situations of over assisting with either steam or air
have become exacerbated, leading to the degradation of flare combustion
efficiency. Many HON and P&R I facilities operate directly downstream
from refineries and other petrochemical plants (e.g., ethylene
production plants) and, consequently, likely burn similar types of
waste gas constituents to a refinery or petrochemical plant (e.g.,
olefins and hydrogen). Given that flares at petrochemical plants, SOCMI
facilities, and a polymers and resins plant were also included in the
flare dataset that formed the underlying basis of the new standards for
refinery flares, we are proposing to apply the finalized suite of
operational and monitoring requirements for refinery flares \120\ to
those flares in the SOCMI source category that control emissions from
HON and P&R I processes. Therefore, these proposed amendments at 40 CFR
63.108 (for HON) and 40 CFR 63.508 (for P&R I) will ensure that
continuous compliance with the CAA section 112(d)(2) and (3) standards
is achieved for HON and P&R I facilities that use flares as APCDs to
meet the MACT standards at all times when controlling HAP emissions.
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\118\ 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.
\119\ For a list of studies, refer to the technical report
titled Parameters for Properly Designed and Operated Flares, in
Docket ID Item No. EPA-HQ-OAR-2010-0682-0191.
\120\ See 40 CFR 63.670 and 40 CFR 63.671 (originally finalized
in 80 FR 75178 on December 1, 2015; and amended in 81 FR 45232 on
July 13, 2016, in 83 FR 60696 on November 26, 2018, and in 85 FR
6064 on February 4, 2020).
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The General Provisions of 40 CFR 63.11(b) specify that flares be:
(1) Steam-assisted, air-assisted, or non-assisted; (2) operated at all
times when emissions may be vented to them; (3) designed for and
operated with no visible emissions (except for periods not to exceed a
total of 5 minutes during any 2 consecutive hours); and (4) operated
with the presence of a pilot flame at all times. These General
Provisions also specify both the minimum heat content of gas combusted
in the flare and maximum exit velocity at the flare tip. The General
Provisions specify monitoring for the presence of the pilot flame and
the operation of a flare with no visible emissions. We are proposing to
revise the General Provisions table to NESHAP subpart F (Table 3) and
the General Provisions table to NESHAP subpart U (Table 1), entries for
40 CFR 63.8(a)(4) and 40 CFR 63.11 such that these provisions do not
apply to flares because we are proposing to replace these provisions
with new standards we are proposing for flares used to comply with the
MACT standards in the HON and P&R I.
In 2012, the EPA compiled information and test data collected on
flares and summarized its preliminary findings on operating parameters
that affect flare combustion efficiency in a technical report titled
Parameters for Properly Designed and Operated Flares, in Docket ID Item
No. EPA-HQ-OAR-2010-0682-0191.\121\ The EPA submitted this report,
along with a charge statement and a set of charge questions, to an
external peer review panel.\122\ The panel, consisting of individuals
representing a variety of backgrounds and perspectives (i.e., industry,
academia, environmental experts, and industrial flare consultants),
concurred with the EPA's assessment that the following three primary
factors affect flare performance: (1) The flow of the vent gas to the
flare; (2) the amount of assist media (e.g., steam or air) added to the
flare; and (3) the combustibility of the vent gas/assist media mixture
in the combustion zone (i.e., the net heating value, lower
flammability, and/or combustibles concentration) at the flare tip. In
response to peer review comments, the EPA performed a validation and
usability analysis on all available test data as well as a failure
analysis on potential parameters discussed in the technical report as
indicators of flare performance. The peer review comments are in the
document titled Peer Review of Parameters for Properly Designed and
Operated Flares, available in Docket ID Item No. EPA-HQ-OAR-2010-0682-
0193, which has been incorporated into the docket for this rulemaking.
These analyses resulted in a change to the population of test data that
the EPA used and helped form the basis for the flare operating limits
promulgated in the 2015 Petroleum Refinery Sector MACT final rule at 40
CFR part 63, subpart CC (80 FR 75178).\123\ We are also relying on the
same analyses and proposing the same operating limits for flares used
as APCDs in the SOCMI source category that control emissions from HON
processes (hereafter referred to as ``HON flares''). The Agency
believes, given the results from the various data analyses conducted
for the Petroleum Refinery Sector rule, that the operating limits
promulgated for flares used in the petroleum refinery sector are also
appropriate and reasonable for HON flares, and will ensure that these
flares meet the HAP destruction and removal efficiency at all times.
Therefore, we are proposing at 40 CFR 63.108 (for HON processes) and 40
CFR 63.508 (for P&R I processes) to replace all flare requirements
throughout the HON \124\ and P&R I \125\ with the Petroleum Refinery
Sector rule flare definitions and requirements in 40 CFR part 63,
subpart CC, with certain clarifications and exemptions discussed in
this section of the preamble, 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 flares in the SOCMI source
category, 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.
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\121\ See section II.D of this preamble, which addresses the
incorporation by reference of certain docket files such as this one
into the docket for this rulemaking.
\122\ These documents can also be found at https://www.epa.gov/stationary-sources-air-pollution/review-peer-review-parameters-properly-designed-and-operated-flares.
\123\ See the document titled Flare Performance Data: Summary of
Peer Review Comments and Additional Data Analysis for Steam-Assisted
Flares, in Docket ID Item No. EPA-HQ-OAR-2010-0682-0200 for a more
detailed discussion of the data quality and analysis; the document
titled Petroleum Refinery Sector Rule: Operating Limits for Flares,
in Docket ID Item No. EPA-HQ-OAR-2010-0682-0206 for a more detailed
discussion of the failure analysis and the document titled Flare
Control Option Impacts for Final Refinery Sector Rule, in Docket ID
Item No. EPA-HQ-OAR-2010-0682-0748 for additional analyses on flare
performance standards based on public comments received on the
proposed Petroleum Refinery Sector rule.
\124\ Refer to proposed 40 CFR 63.108(a)(1) through (a)(22) for
a list of HON provisions that would no longer apply.
\125\ Refer to proposed 40 CFR 63.508(a)(1) through (a)(32) for
a list of P&R I provisions that would no longer apply.
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The remainder of this section of the preamble includes a discussion
of requirements that we are proposing for HON and P&R I flares, along
with impacts and costs associated with these proposed revisions.
Specifically, this action proposes that HON and P&R I flares operate
pilot flame systems continuously and that flares operate with no
visible emissions (except for periods not to 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. In addition, this
action proposes to consolidate measures related to flare tip velocity
and proposes new operational and monitoring requirements related to the
combustion zone gas. Further, in keeping with the elimination of the
SSM exemption as discussed in section III.E.1 of this preamble, this
action proposes a work practice standard related to the visible
emissions during periods when the flare is operated above its smokeless
capacity (e.g., periods of emergency flaring). Currently, the MACT
standards in the HON and P&R I cross-reference the General Provisions
at 40 CFR
[[Page 25149]]
63.11(b) for the operational requirements for flares used as APCD. This
proposal eliminates cross-references to the General Provisions and
instead specifies all new operational and monitoring requirements that
are intended to apply to flares used as APCDs in the HON and P&R I
standards. We are also proposing to include provisions at 40 CFR
63.110(j) that address compliance with the proposed operating and
monitoring requirements for flares in lieu of flare-related
requirements of any other 40 CFR part 60, 61, or 63 rule.
a. Pilot Flames
The HON and P&R I reference the flare requirements in 40 CFR
63.11(b), which specify that a flare used as an APCD should operate
with a pilot flame present at all times. Pilot flames are proven to
improve flare flame stability, and even short durations of an
extinguished pilot could cause a significant reduction in flare
destruction efficiency. In this proposal, we are proposing to remove
the cross-reference to the General Provisions for HON and P&R I flares
and instead cross-reference 40 CFR part 63, subpart CC, to include in
the HON the existing provision that flares operate with a pilot flame
at all times and be continuously monitored for a pilot flame using a
thermocouple or any other equivalent device. We are also proposing to
add a continuous compliance measure that would consider each 15-minute
block when there is at least 1 minute where no pilot flame is present
when regulated material is routed to the flare as a deviation from the
standard. Refer to 40 CFR 63.108 (for HON), 40 CFR 63.508 (for P&R I),
and 40 CFR 63.670(b) and (g) for these proposed requirements. See
section III.D.1.e of this preamble for our rationale for proposing to
use a 15-minute block averaging period for determining continuous
compliance. We solicit comment on the proposed revisions for flare
pilot flames.
b. Visible Emissions
The HON and P&R I reference 40 CFR 63.11(b), which specifies that a
flare used as an APCD should operate with visible emissions for no more
than 5 minutes in a 2-hour period. Owners or operators of these flares
are required to conduct an initial performance demonstration for
visible emissions using Method 22 of Appendix A-7 to 40 CFR part 60
(``Method 22''). We are proposing to remove the cross-reference to the
General Provisions for HON and P&R I flares and instead cross-reference
40 CFR part 63, subpart CC, to include this same limitation on visible
emissions. We are also proposing to clarify that the initial 2-hour
visible emissions demonstration should be conducted the first time
regulated materials are routed to the flare.
With regard to continuous compliance with the visible emissions
limitation, we are proposing daily visible emissions monitoring for HON
and P&R I flares whenever regulated material is routed to the flare and
also visible emissions monitoring whenever visible emissions are
observed from the flare. On days that the flare receives regulated
material, we are proposing that owners or operators of HON and P&R I
flares monitor visible emissions at a minimum of once per day while the
flare is receiving regulated material using an observation period of 5
minutes and Method 22. Additionally, whenever regulated material is
routed to a flare and there are visual emissions from the flare, we are
proposing that another 5-minute visible emissions observation period be
performed using Method 22, even if the minimum required daily visible
emission monitoring has already been performed. For example, if an
employee observes visible emissions, the owner or operator of the flare
would perform a 5-minute Method 22 observation to check for compliance
upon initial observation or notification of such event. In addition, in
lieu of daily visible emissions observations performed using Method 22,
we are proposing that owners and operators be allowed to use video
surveillance cameras. We believe that video surveillance cameras would
be at least as effective as the proposed daily 5-minute visible
emissions observations using Method 22.
We are also proposing to extend the observation period for a HON or
P&R I flare to 2 hours whenever visible emissions are observed for
greater than 1 continuous minute during any of the 5-minute observation
periods. Refer to 40 CFR 63.108 (for HON), 40 CFR 63.508 (for P&R I),
and 40 CFR 63.670(c) and (h) for these proposed requirements. We
acknowledge that operating a flare near the incipient smoke point (the
point at which black smoke begins to form within the flame) results in
good combustion at the flare tip; however, smoking flares can
contribute significantly to emissions of particulate matter that is 2.5
micrometers in diameter or smaller (PM2.5). Thus, while
increasing the allowable period for visible emissions may be useful
from an operational perspective, we do not believe the allowable period
for visible emissions should be increased to more than 5 minutes in any
2-hour period. We solicit comment on the proposed allowable period for
visible emissions from flares.
As discussed later in this section, we are proposing additional
operational and monitoring requirements for HON and P&R I flares that
we expect will result in owners or operators of CMPUs installing
equipment that can be used to fine-tune and control the amount of
assist steam or air introduced at the flare tip such that combustion
efficiency of the flare will be maximized. These monitoring and control
systems will assist these flare owners or operators to operate near the
incipient smoke point without exceeding the visible emissions limit.
While combustion efficiency may be highest at the incipient smoke
point, it is not significantly higher than the combustion efficiency
achieved by the proposed operating limits discussed in section
III.D.1.d of this preamble. As seen in the performance curves for
flares, there is very limited improvement in flare performance beyond
the performance achieved at the proposed operating limits (see document
titled Petroleum Refinery Sector Rule: Operating Limits for Flares, in
Docket ID Item No. EPA-HQ-OAR-2010-0682-0206, which has been
incorporated into the docket for this rulemaking). We solicit comments
and data on appropriate periods of visible emissions that would
encourage operation at the incipient smoke point.
In addition, we are proposing that the owner or operator establish
the smokeless capacity of each HON and P&R I flare based on design
specification of the flare, and that the visible emissions limitation
only apply when the flare vent gas flow rate is below its smokeless
capacity. We are proposing a work practice standard for the limited
times (i.e., during emergency releases) when the flow to a flare
exceeds the smokeless capacity of the flare, based on comments the EPA
received on the proposed Petroleum Refinery Sector rule. Refer to 40
CFR 63.108 (for HON), 40 CFR 63.508 (for P&R I), and 40 CFR 63.670(o)
for these proposed provisions. In the Petroleum Refinery Sector final
rule, the EPA explained that numerous comments on the proposal
suggested that flares are not designed to meet the visible emissions
requirements when operated beyond their smokeless capacity (80 FR
75178). According to commenters, flares are typically designed to
operate in a smokeless manner at 20 to 30 percent of full hydraulic
load. Thus, they claimed, flares have two different design capacities:
A ``smokeless capacity'' to handle normal operations and typical
process variations and a ``hydraulic load capacity'' to handle very
large volumes
[[Page 25150]]
of gases discharged to the flare as a result of an emergency shutdown.
According to commenters, this is inherent in all flare designs and has
not previously been an issue because flare operating limits did not
apply during malfunction events.
For this proposed work practice standard, owners or operators would
need to develop a flare management plan for HON and P&R I flares that
identifies procedures for limiting discharges to the flare as a result
of process upsets or malfunctions that cause the flare to exceed its
smokeless capacity. In addition, for any flare that exceeds both the
smokeless design capacity and visible emissions limit, we are proposing
that owners or operators would need to conduct a specific root cause
analysis and take corrective action to prevent the recurrence of a
similarly caused event (similar to the prevention measures we are
proposing in this rule to minimize the likelihood of a PRD release, see
section III.D.2.a of this preamble). We are proposing that if the root
cause analysis indicates that the exceedance of the visible emissions
limit is caused by operator error or poor maintenance, then the
exceedance would be considered a deviation from the work practice
standard. We are also proposing that a second event within a rolling 3-
year period from the same root cause on the same equipment would be
considered a deviation from the standard. Finally, we are proposing
that a third visible emissions limit exceedance occurring from the same
flare in a rolling 3-year period would be a deviation from the work
practice standard, regardless of the cause.
In several of the EPA's previous impact analyses (for petroleum
refinery flares and ethylene production flares),\126\ the EPA
established the number of events in a given time period that would be
the ``backstop'' (i.e., a violation of the standard). In each of these
analyses, the EPA evaluated four different timing alternatives (2 in 5
years; 2 in 3 years; 3 in 5 years; and 3 in 3 years) based on the
number of existing flares evaluated over a 20-year period, and
ultimately the EPA concluded that 3 events in 3 years would be
``achievable'' for the average of the best performing flares. We see no
reason why this would be any different for HON and P&R I flares. Even
if a best-performing flare ``typically'' only has one event every seven
years, the fact that these events are random by nature (unpredictable,
not under the direct control of the owner or operator) makes it
difficult to use a 5-year time span. Based on this analysis, three
events in 3 years would appear to be ``achievable'' for the average of
the best performing flares.
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\126\ See EPA-HQ-OAR-2010-0682-0793, EPA-HQ-OAR-2010-0682-0794,
and EPA-HQ-OAR-2017-0357-0017.
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c. Flare Tip Velocity
This action consolidates provisions related to flare tip velocity
for HON and P&R I flares. The HON and P&R I reference the flare
provisions in 40 CFR 63.11(b), which specify maximum flare tip
velocities based on flare type (non-assisted, steam-assisted, or air-
assisted) and the net heating value of the flare vent gas. Based on
data provided to EPA in response to our CAA section 114 request (see
section II.C of this preamble), 10 of the 18 flares that HON and P&R I
facilities reported using as APCDs are either steam- or air-assisted
(see the document titled Control Option Impacts for Flares Located in
the SOCMI Source Category that Control Emissions from Processes Subject
to HON and for Flares that Control Emissions from Processes Subject to
Group I and Group II Polymers and Resins NESHAPs, which is available in
the docket for this rulemaking). Maximum flare tip velocities are
required to ensure that the flame does not ``lift off'' the flare
(i.e., a condition where a flame separates from the tip of the flare
and there is space between the flare tip and the bottom of the flame),
which could cause flame instability and/or potentially result in a
portion of the flare gas being released without proper combustion. We
are proposing to remove the cross-reference to the General Provisions
for HON and P&R I flares and instead cross-reference 40 CFR part 63,
subpart CC, to consolidate the provisions for maximum flare tip
velocity into the HON and P&R I as a single equation, irrespective of
flare type (i.e., steam-assisted, air-assisted, or non-assisted). Refer
to 40 CFR 63.108 (for HON), 40 CFR 63.508 (for P&R I), and 40 CFR
63.670(d), (i), and (k) for these proposed provisions.
Based on analysis conducted for the Petroleum Refinery Sector rule,
the EPA identified air-assisted test runs with high flare tip
velocities that had high combustion efficiencies (see the document
titled Petroleum Refinery Sector Rule: Evaluation of Flare Tip Velocity
Requirements, in Docket ID Item No. EPA-HQ-OAR-2010-0682-0212). These
test runs exceeded the maximum flare tip velocity limits for air-
assisted flares using the linear equation in 40 CFR 63.11(b)(8). When
these test runs were compared with the test runs for non-assisted and
steam-assisted flares, air-assisted flares appeared to have the same
operating envelope as the non-assisted and steam-assisted flares.
Therefore, for air-assisted HON and P&R I flares, we are proposing the
use of the same equation that non-assisted and steam-assisted flares
currently use to establish the flare tip velocity operating limit. We
are also proposing that the owner or operator determine the flare tip
velocity on a 15-minute block average basis. See section III.D.1.e of
this preamble for our rationale for proposing to use a 15-minute block
averaging period for determining continuous compliance.
Finally, we are also proposing not to include the provision for the
special flare tip velocity equation in the General Provisions at 40 CFR
63.11(b)(6)(i)(A) for non-assisted HON and P&R I flares with hydrogen
content greater than 8 percent. This equation, which was developed
based on limited data from a chemical manufacturer, has very limited
applicability for flares used as APCDs in the SOCMI source category
because it only provides an alternative for non-assisted flares with
large quantities of hydrogen. Available data indicates that
approximately 50 percent of the flares used at HON and P&R I facilities
are either steam-assisted or air-assisted, which seems to indicate that
approximately 50 percent are non-assisted flares. Instead, we are
proposing compliance alternatives that we believe provide a better way
for HON and P&R I flares with high hydrogen content to comply with the
rule while ensuring proper destruction performance of the flare (see
section III.D.1.d of this preamble for the proposed compliance
alternatives). Therefore, for non-assisted HON and P&R I flares with
hydrogen content greater than 8 percent that are used as ACPDs, we are
not proposing to include this special flare tip velocity equation as a
compliance alternative. We request comment on the need to include this
equation.
d. Net Heating Value of the Combustion Zone Gas
The current provisions for flares in 40 CFR 63.11(b) specify that
the flare vent gas meet a minimum net heating value of 200 British
thermal units per standard cubic foot (Btu/scf) for non-assisted flares
and 300 Btu/scf for air- and steam-assisted flares. The HON and P&R I
reference these provisions, but neither the General Provisions nor the
HON or P&R I include specific requirements for monitoring the net
heating value of the flare vent gas. Moreover, recent flare testing
results indicate that meeting a minimum net heating value limit alone
does not address instances when the flare may be
[[Page 25151]]
over-assisted because it only considers the net heating value of the
gas being combusted in the flare and nothing else (e.g., no assist
media). However, many industrial flares use steam or air as an assist
medium to protect the design of the flare tip, promote turbulence for
the mixing, induce air into the flame, and operate with no visible
emissions. Using excessive steam or air results in dilution and cooling
of flared gases and can lead to operating a flare outside its stable
flame envelope, reducing the destruction efficiency of the flare. In
extreme cases, over-steaming or excess aeration can snuff out a flame
and allow regulated material to be released into the atmosphere without
complete combustion. As previously noted, because available data
indicate that a preponderance of all HON and P&R I flares are either
steam- or air-assisted, it is critical that we ensure the assist media
is accounted for in some form. Recent flare test data have shown that
the best way to account for situations of over-assisting is to consider
the gas mixture properties at the flare tip in the combustion zone when
evaluating the ability to combust efficiently. As discussed in the
introduction to this section, the external peer review panel concurred
with our assessment that the combustion zone properties at the flare
tip are critical parameters to know in determining whether a flare will
achieve good combustion. The General Provisions, however, solely rely
on the net heating value of the flare vent gas, and we have determined
that is not sufficient for the flares at issue.
In this proposal, in lieu of requiring compliance with the
operating limits for net heating value of the flare vent gas in the
General Provisions, we are proposing to cross-reference 40 CFR part 63,
subpart CC, to include in the HON and P&R I a single minimum operating
limit for the net heating value in the combustion zone gas (NHVcz) of
270 Btu/scf during any 15-minute period for steam-assisted, air-
assisted, and non-assisted HON and P&R I flares. Refer to 40 CFR 63.108
(for HON), 40 CFR 63.508 (for P&R I), and 40 CFR 63.670I and (m) for
these proposed provisions. The Agency believes, given the results from
the various data analyses conducted for the Petroleum Refinery Sector
rule, that this NHVcz operating limit promulgated for flares in the
Petroleum Refinery Sector source category is also appropriate and
reasonable and will ensure HON and P&R I flares meet the HAP
destruction efficiencies in the standard at all times when operated in
concert with the other proposed flare provisions (e.g., pilot flame,
visible emissions, and flare tip velocity requirements) (see the
memoranda titled: Petroleum Refinery Sector Rule: Operating Limits for
Flares and Flare Control Option Impacts for Final Refinery Sector Rule,
in Docket ID Item No. EPA-HQ-OAR-2010-0682-0206 and EPA-HQ-OAR-2010-
0682-0748, respectively). In addition, we are proposing that owners or
operators may use a corrected heat content of 1,212 Btu/scf for
hydrogen, instead of 274 Btu/scf, to demonstrate compliance with the
NHVcz operating limit for HON and P&R I flares; however, owners or
operators who wish to use the corrected hydrogen heat content must have
a system capable of monitoring for the hydrogen content in the flare
vent gas. The 1,212 Btu/scf value is based on a comparison between the
lower flammability limit and net heating value of hydrogen compared to
light organic compounds and has been used in several consent decrees
issued by the EPA. Based on analyses conducted for the Petroleum
Refinery Sector rule (see the document titled Flare Control Option
Impacts for Final Refinery Sector in Docket ID Item No. EPA-HQ-OAR-
2010-0682-0748), the EPA determined that using a 1,212 Btu/scf value
for hydrogen greatly improves the correlation between combustion
efficiency and the combustion zone net heating value over the entire
array of data.
Furthermore, in addition to the NHVcz operating limit, we are
proposing a net heating value dilution parameter (NHVdil) for certain
HON and P&R I flares that operate with perimeter assist air. Refer to
40 CFR 63.108 (for HON), 40 CFR 63.508 (for P&R I), and 40 CFR
63.670(f) and (n) for these proposed provisions. For air-assisted
flares, use of too much perimeter assist air can lead to poor flare
performance. Furthermore, based on our analysis of the air-assisted
flare datasets (see the document titled Petroleum Refinery Sector Rule:
Operating Limits for Flares, in Docket ID Item No. EPA-HQ-OAR-2010-
0682-0206), we determined a NHVdil of 22 British thermal units per
square foot is necessary to ensure that there is enough combustible
material available to adequately combust the gas and pass through the
flammability region and also ensure that degradation of flare
performance from excess aeration does not occur. We found that
including the flow rate of perimeter assist air in the calculation of
the NHVcz does not identify all instances of excess aeration and could
(in some instances) even allow facilities to send very dilute vent
gases to the flare that would not combust (i.e., vent gases below their
lower flammability limit could be sent to flare). Instead, the data
suggest that the diameter of the flare tip, in concert with the amount
of perimeter assist air (and other parameters used to determine NHVcz),
provide the inputs necessary to calculate whether this type of flare is
over-assisted. This dilution parameter is consistent with the
combustion theory that the more time the gas spends in the flammability
region above the flare tip, the more likely it will combust. Also,
because both the volume of the combustion zone (represented by the
diameter) and how quickly this gas is diluted to a point below the
flammability region (represented by perimeter assist air flow rate)
characterize this time, it is logical that we propose such a parameter.
We also found that some assist steam lines are purposely designed
to entrain air into the lower or upper steam at the flare tip; and for
flare tips with an effective tip diameter of 9 inches or more, there
are no flare tip steam induction designs that can entrain enough assist
air to cause a flare operator to have a deviation from the NHVdil
operating limit without first deviating from the NHVcz operating limit.
Therefore, we are proposing to allow owners or operators of HON and P&R
I flares whose only assist air is from perimeter assist air entrained
in lower and upper steam at the flare tip and with a flare tip diameter
of 9 inches or greater to comply only with the NHVcz operating limit.
Steam-assisted flares with perimeter assist air and an effective tip
diameter of less than 9 inches would remain subject to the requirement
to account for the amount of assist air intentionally entrained within
the calculation of NHVdil. However, we recognize that this assist air
cannot be directly measured, but the quantity of air entrained is
dependent on the assist steam rate and the design of the steam tube's
air entrainment system. Therefore, we are proposing provisions to
specify that owners or operators of these smaller diameter steam-
assisted HON flares use the steam flow rate and the maximum design air-
to-steam ratio of the steam tube's air entrainment system for
determining the flow rate of this assist air. Using the maximum design
ratio will tend to over-estimate the assist air flow rate, which is
conservative with respect to ensuring compliance with the NHVdil
operating limit.
Finally, we are proposing that owners or operators record and
calculate 15-minute block average values for these parameters. Our
rationale for selecting a
[[Page 25152]]
15-minute block averaging period is provided in section III.D.1.e of
this preamble. We solicit comment on the proposed revisions related to
NHVcz.
e. Data Averaging Periods for Flare Gas Operating Limits
Except for the visible emissions operating limits as described in
section III.D.1.b of this preamble, we are proposing to use a 15-minute
block averaging period for each proposed flare operating parameter
(i.e., presence of a pilot flame, flare tip velocity, and NHVcz) to
ensure that HON and P&R I flares are operated within the appropriate
operating conditions. We consider a short averaging time to be the most
appropriate for assessing proper flare performance because flare vent
gas flow rates and composition can change significantly over short
periods of time. Furthermore, because destruction efficiency can fall
precipitously when a flare is controlling vent gases below (or outside)
the proposed operating limits, short time periods where the operating
limits are not met could seriously impact the overall performance of
the flare. Refer to the Petroleum Refinery Sector rule preambles (79 FR
36880 and 80 FR 75178) for further details supporting why we believe a
15-minute averaging period is appropriate.
Given the short averaging times for the operating limits, we are
proposing special calculation methodologies to enable owners or
operators to use ``feed forward'' calculations to ensure compliance
with the operating limits on a 15-minute block average for HON and P&R
I flares. Specifically, we propose using the results of the
compositional analysis determined just prior to a 15-minute block
period for the next 15-minute block average. Owners or operators of HON
and P&R I flares will then know the vent gas properties for the
upcoming 15-minute block period and can adjust assist gas flow rates
relative to vent gas flow rates to comply with the proposed operating
limits. In other words, ``feed forward'' means that owners or operators
would use the net heating value in the vent gas (NHVvg) going into the
flare in one 15-minute period to adjust the assist media (i.e., steam
or air) and/or the supplemental gas in the next 15-minute period, as
necessary, to calculate an NHVcz limit of 270 Btu/scf or greater using
the proposed equation. We recognize that when a subsequent measurement
value is determined, the instantaneous NHVcz based on that
compositional analysis and the flow rates that exist at the time may
not be above 270 Btu/scf. We are proposing that this is not a deviation
from the operating limit. Rather, we propose that the owner or operator
is only required to make operational adjustments based on that
information to achieve, at a minimum, the net heating value limit for
the subsequent 15-minute block average. We are, however, proposing that
failure to make adjustments to assist media or supplemental natural gas
using the NHVvg from the previous period in the equation provided for
calculating an NHVcz limit of 270 Btu/scf, would be a deviation from
the operating limit. Alternatively, because the owner or operator could
directly measure the NHVvg on a more frequent basis, such as with a
calorimeter (and optional hydrogen analyzer), the process control
system is able to adjust more quickly, and the owner or operator can
make adjustments to assist media or supplemental natural gas more
quickly. In this manner, the owner or operator is not limited by
relying on NHVvg data that may not represent the current conditions. We
are, therefore, also proposing that the owner or operator may opt to
use the NHVvg in such instances from the same period to comply with the
operating limit. For examples of ``feed forward'' calculations, please
see Attachment 3 of the document titled Flare Control Option Impacts
for Final Refinery Sector Rule, in Docket ID Item No. EPA-HQ-OAR-2010-
0682-0748.
We are also proposing to clarify that when determining compliance
with the flare tip velocity and combustion zone operating limits
specified in 40 CFR 63.670(d) and (e), the initial 15-minute block
period starts with the 15-minute block that includes a full 15 minutes
of the flaring event. In other words, we are proposing to clarify that
the owner or operator demonstrate compliance with the velocity and
NHVcz requirements starting with the block that contains the fifteenth
minute of a flaring event; and 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. We solicit comment
on these proposed revisions.
f. Flares in Dedicated Service
In lieu of requiring the composition of the vent gas and the NHVvg
to be continuously monitored, we are proposing an alternative
monitoring approach for HON and P&R I flares that are in dedicated
service that have consistent composition and flow. We believe that
these types of flares, which have limited flare vent gas streams, do
not need to have the same type of ongoing monitoring requirements as
those with more variable waste streams. Thus, we are proposing an
option that owners or operators can use to demonstrate compliance with
the operating requirements for HON and P&R I flares that are in
dedicated service to a specific emission source, such as a transfer
rack operation consistently loading the same material. We are proposing
that owners or operators will need to submit an application for the use
of this alternative compliance option. We are proposing that the
application include a description of the system, characterization of
the vent gases that could be routed to the flare based on a minimum of
seven grab samples (14 daily grab samples for continuously operated
flares), and specification of the net heating value that will be used
for all flaring events (based on the minimum net heating value of the
grab samples). In other words, for HON and P&R I flares that are in
dedicated service, we are proposing that the minimum NHVvg determined
from the grab samples could be used in the equation at 40 CFR
63.670(m)(1) for all flaring events to determine NHVcz. We are also
proposing to allow engineering estimates to characterize the amount of
gas flared and the amount of assist gas introduced into the system. For
example, we believe that the use of fan curves to estimate air assist
rates would be acceptable. We propose that flare owners or operators
would use the net heating value determined from the initial sampling
phase and measured or estimated flare vent gas and assist gas flow
rates, if applicable, to demonstrate compliance with the standards.
Refer to 40 CFR 63.108 and 40 CFR 63.670(j)(6) for these proposed
provisions. Finally, for owners and operators that must comply with the
continuous monitoring requirements, we are proposing additional
clarifications and requirements at 40 CFR 63.108 when using a gas
chromatograph or mass spectrometer for compositional analysis. We
solicit comment on the proposed revisions related to flares in
dedicated service.
g. Pressure-Assisted Multi-Point Flares
The EPA is also proposing to add requirements into the HON (but not
P&R I) for pressure-assisted multi-point flares given that these types
of APCD are used to control waste gases from processes subject to the
HON during SSM. Pressure-assisted flares are conceptually similar, yet
technically different in both design and operation compared to more
traditional elevated flare tip designs (e.g., steam-assisted, air-
assisted, and non-assisted flare tips). Pressure-assisted flares
operate by taking advantage of the pressure upstream of
[[Page 25153]]
the flare tip to create a condition whereby air is drawn into contact
and mixed with high exit velocity flared gas, resulting in smokeless
flare operation and emissions reductions at least equivalent to those
of traditional flare types, if properly designed and operated.
Pressure-assisted flares can be used in a single flare burner type
layout or in staged arrays with many identical flare burners. These
staged arrays can be elevated or at ground level; however, we are only
aware of ground level staged array systems, that are commonly referred
to as multi-point ground flares (MPGFs), at six facilities used as
APCDs in the SOCMI source category that control emissions from HON
processes.\127\ MPGFs have multiple (e.g., hundreds) flare burners at
ground level. The flare burners in a MPGF are designed with a staging
system that opens and closes staging valves according to gas pressure
in the flare header such that the stages, and accompanying flare
burners for those stages, are activated to control emissions as the
flare vent gas flow and pressure increase in the flare header, or are
deactivated as the flare vent gas flow and pressure decrease in the
flare header. The flare burners in a MPGF are typically lit with a
pilot flame system where the first burners on a stage are lit by the
pilot flame and the flame propagates (i.e., cross-lights) down the
stage to the remaining burners on the stage (similar to how burners on
a gas grill would light). The MPGF system is surrounded by a panel type
fence to allow air in for combustion as well as to protect nearby
workers from the radiant heat of the flare system.
---------------------------------------------------------------------------
\127\ One HON flare was reported as a pressure-assisted ground
flare in response to our CAA section 114 request. Based on this
information, in addition to information from alternative means of
emission limitation requests (see Docket ID No. EPA-HQ-OAR-2014-
0738), we estimate there are 6 pressure-assisted MPGF located in the
SOCMI source category that control emissions from processes subject
to the HON.
---------------------------------------------------------------------------
MPGF are often used as secondary flares to control large emissions
events that result during periods of SSM. With the elimination of the
SSM exemption (see section III.E.1 of this preamble for additional
discussion), proposing requirements for this unique flare type for HON
flares is an important consideration given that some facilities
currently use them as APCD. Based on our review of recently approved
alternative means of emission limitation (AMEL) requests for MPGF and
the underlying data analyses that supported those decisions (see
section II.D of this preamble), MPGF can achieve reductions in VOC and
organic HAP at least equivalent to those from traditional elevated
flares; however, different operating requirements are needed for these
flare types to ensure a high level of control is achieved given that
the individual flare burners are designed to operate at high velocities
(i.e., up to sonic velocity). Important considerations for proper
design and operation of MPGF center around the following: (1) Flare
flame stability, (2) pilot flame presence and its interplay with proper
cross-lighting, (3) operation of the MPGF with no visible emissions,
and (4) monitoring of certain parameters of the MPGF and the vent gases
it controls for purposes of compliance assurance.
In reviewing the initial MPGF AMEL requests by Dow Chemical and
ExxonMobil (80 FR 8023-8030, February 13, 2015), the Agency noted two
general conclusions from the test data supporting the AMEL requests
that were consistent with 1985 studies \128\ conducted by the EPA on
pressure-assisted flares. The first general conclusion was that flare
head design can influence the flame stability curve. The second general
conclusion was that stable flare flames and high (greater than 98-99
percent) combustion and destruction efficiencies are attained when
flares are operated within operating envelopes specific to each flare
burner and gas mixture tested. Operation beyond the edge of the
operating envelope can result in rapid flame de-stabilization and a
decrease in combustion and destruction efficiencies. In reviewing all
the available data in the MPGF AMEL docket (i.e., Docket ID No. EPA-HQ-
OAR-2014-0738), we found these two general observations were still
valid conclusions. The data clearly show that for some test runs flare
flameouts occurred, meaning the flares were not operated within the
proper envelope to produce a stable flame. In reviewing these data, we
observed that all flare flameouts occurred for the various burners/
waste gas mixtures tested below an NHVcz of 800 Btu/scf. Thus, we
selected a minimum NHVcz of 800 Btu/scf to ensure the MPGF at
facilities in the SOCMI source category that control emissions from HON
processes are operated within the proper envelope to produce a stable
flame and achieve high destruction efficiencies at least equivalent to
those as the underlying HON MACT standards. Above this level, no flare
flameouts are observed, and high combustion/destruction efficiencies at
least equivalent to those as the underlying HON MACT standards are
achieved. Thus, to that end, we are proposing to not allow use of the
``feed forward'' calculation approach (discussed in section III.D.1.e
of this preamble) to demonstrate compliance with the NHVcz limit of 800
Btu/scf.
---------------------------------------------------------------------------
\128\ Pohl, J. and N. Soelberg. 1985. Evaluation of the
efficiency of industrial flares: Flare head design and gas
composition. EPA-600/2-85-106. Prepared for U.S. EPA Office of Air
Quality Planning and Standards.
---------------------------------------------------------------------------
Another unique characteristic of MPGF is that they may use a cross-
lighting pilot flame system as a means of ignition to initially combust
the waste gases sent to the flare burners on a particular staged array.
Thus, we also reviewed the equipment-specific set-ups in the test data
that allowed for successful cross-lighting of MPGF. Based on review of
the data, it appears that one option would be for facilities to conduct
performance demonstrations to demonstrate successful cross-lighting on
a minimum of three burners (i.e., as outlined in the Framework for
Streamlining Approval of Future Pressure-Assisted MPGF AMEL Requests,
81 FR 23480, April 21, 2016). However, given the data before us in the
MPGF AMEL docket, and rather than requiring facilities to conduct a
performance demonstration, it appears that an equipment standard that
sets an upper limit on the distance between burners of 6 feet will
ensure a successful cross-lighting on a stage of burners in a MPGF.
Furthermore, in reviewing the site-specific AMEL standards that
facilities are complying with for MPGF,\129\ we believe these same
site-specific standards, if applied to all MPGF in the specified
subset, would demonstrate at least equivalent emissions reductions to
the underlying HON MACT standards as well as demonstrate at least
equivalent reductions to the new operational and monitoring
requirements we are proposing for more traditional, elevated flare
tips. Therefore, we are proposing at 40 CFR 63.108(i) that owners or
operators of MPGF at facilities in the SOCMI source category that
control emissions from HON processes: (1) Maintain an NHVcz greater
than or equal to 800 Btu/scf over a short averaging period (i.e., 15-
minutes); (2) continuously monitor the NHVcz and flare vent gas flow
rate; (3) continuously monitor for the presence of a pilot flame, and
if cross-lighting is occurring on a particular stage of burners,
ensuring that each stage of burners that cross-lights must have at
least two pilots with at least one continuously lit and capable of
igniting all regulated material
---------------------------------------------------------------------------
\129\ 80 FR 52426, August 31, 2015; 81 FR 23480, April 21, 2016;
and 82 FR 27822, June 19, 2017.
---------------------------------------------------------------------------
[[Page 25154]]
that is routed to that stage of burners; (4) operate the MPGF with no
visible emissions (except for 5 minutes during any 2 consecutive
hours); (5) maintain a distance of no greater than 6 feet between any
two burners on a stage of burners that use cross-lighting; \130\ and
(6) monitor to ensure the staging valves for each stage of the MPGF
operate properly so that the flare will control vent gases within the
range of the tested conditions based on the flare manufacturer's
recommendations.
---------------------------------------------------------------------------
\130\ We are proposing that this burner-to-burner distance is
the distance when measured from the center of one burner to the next
burner.
---------------------------------------------------------------------------
Finally, although we are unaware of any HON facilities that use
multi-point elevated flares in the specified flare subset, we recognize
that an owner or operator may elect to use this type of flare design in
the future. Given the design similarities of a multi-point elevated
flare when compared to a MPGF (i.e., each flare type uses pressure-
assisted burners with staged arrays), we determined that our analyses
of the test data (including our review of approved AMEL requests)
related to MPGF that control waste gases could also apply to multi-
point elevated flares in the specified subset that combust waste gases.
Therefore, we are proposing that owners and operators of multi-point
elevated flares meet the same requirements that we are proposing for
MPGF. In other words, the proposed requirements discussed in this
section of the preamble would apply to all pressure-assisted multi-
point flares (i.e., MPGF and multi-point elevated flares) at facilities
in the SOCMI source category that control emissions from HON processes.
We are soliciting comment on whether this approach is appropriate, and
whether test data are available for multi-point elevated flares that
control waste gases from HON facilities. Also, given that some owners
and operators of CMPUs are currently operating under an approved AMEL,
and these owners and operators are likely to have already installed
more sophisticated equipment (e.g., a gas chromatograph) than what is
required to comply with these proposed requirements for pressure-
assisted multi-point flares, we are proposing that pressure-assisted
multi-point flares subject to an approved AMEL may continue to comply
with the approved AMEL in lieu of these proposed requirements for
pressure-assisted multi-point flares. We also are soliciting comment on
whether we should extend allowance of this option to P&R I facilities,
as many sources are collocated with HON and may use this same type of
control device as a backup. As we are currently unaware of any P&R I
facilities using pressure-assisted multi-point flares, we solicit
comment whether test data are available for these flare types that
control waste gases from P&R I processes.
h. Impacts of the Proposed Flare Operating and Monitoring Requirements
The EPA expects that the newly proposed requirements for flares
used as APCDs in the SOCMI source category discussed in this section
will affect all flares at HON and P&R I processes. Based on facility
responses to our CAA section 114 request, we estimate that there are
345 flares of traditional elevated flare tip designs (e.g., steam-
assisted, air-assisted, and non-assisted flare tips) operating at HON
CMPUs that receive flare vent gas flow on a regular basis (i.e., other
than during periods of SSM). We estimate that there are 31 flares of
traditional elevated flare tip designs operating at P&R I EPPUs that
receive flare vent gas flow on a regular basis. Also, based on facility
responses to our CAA section 114 request and information received from
AMEL requests (see section II.D of this preamble), we estimate there
are six pressure-assisted MPGF used to control waste gases from
processes subject to the HON during SSM. Costs were estimated for each
flare for a given facility, considering current monitoring systems
already installed on each individual flare. Given that the same type of
equipment is used for flares in the SOCMI source category and for the
petroleum refinery sector, costs for any additional monitoring systems
needed were estimated based on installed costs received from petroleum
refineries and, if installed costs were unavailable, costs were
estimated based on vendor-purchased equipment. The baseline emission
estimate and the emission reductions achieved by the proposed rule were
estimated based on current vent gas and steam flow data submitted by
industry representatives. The results of the impact estimates are
summarized in Table 28 of this preamble for Flares in the SOCMI Source
Category that control emissions from HON processes including P&R I & II
flares collocated with HON processes. The results of the impact
estimates are summarized in Table 29 of this preamble for Flares in the
SOCMI source category that control emissions from P&R I processes. We
note that the requirements for HON and P&R I flares that we are
proposing will ensure compliance with the MACT standards in the HON and
P&R I when flares are used as an APCD. Because we are not changing the
underlying MACT standards in the HON and P&R I, we did not include any
of the estimated excess emissions from flares in the summary of total
estimated emissions reductions for this action. However, we estimate
that the proposed operational and monitoring requirements have the
potential to reduce excess emissions from HON flares (including from
P&R I flares collocated with HON processes) by approximately 4,717 tpy
of HAP and 19,325 tpy of VOC; and from P&R I flares (not collocated
with HON processes) by approximately 141 tpy of HAP and 564 tpy of VOC.
The VOC compounds are non-methane, non-ethane total hydrocarbons.
According to the emissions inventory file we used to assess residual
risk (see section II.F.1 of this preamble), there are approximately 80
individual HAP compounds included in the emission inventory for flares,
but many of these are emitted in trace quantities. Almost half of the
HAP emissions from flares are attributable to hexane, benzene, and
methanol, followed by 1,3-butadiene and vinyl acetate. For more detail
on the impact estimates, see the document titled Control Option Impacts
for Flares Located in the SOCMI Source Category that Control Emissions
from Processes Subject to HON and for Flares that Control Emissions
from Processes Subject to Group I and Group II Polymers and Resins
NESHAPs, which is available in the docket for this rulemaking. As
previously mentioned in section III.C.3.b of this preamble, we are also
proposing these same flare operating and monitoring requirements for
NSPS subpart IIIa, NNNa, and RRRa under CAA section 111(b)(1)(B).
[[Page 25155]]
Table 28--Nationwide Cost Impacts for Flares in the SOCMI Source
Category That Control Emissions From HON Processes Including P&R I
Flares Collocated With HON Processes
------------------------------------------------------------------------
Total
Total capital annualized
Control description investment costs (million
(million $) $/yr)
------------------------------------------------------------------------
Flare Operational and Monitoring 323.1 67.8
Requirements...........................
Work Practice Standards for Flares 3.34 0.79
Operating Above Their Smokeless
Capacity...............................
-------------------------------
Total............................... 326.4 68.7
------------------------------------------------------------------------
Table 29--Nationwide Cost Impacts for Flares in the SOCMI Source
Category That Control Emissions From P&R I Processes
------------------------------------------------------------------------
Total
Total capital annualized
Control description investment costs
(million $) (million $/yr)
------------------------------------------------------------------------
Flare Operational and Monitoring 6.93 1.46
Requirements...........................
Work Practice Standards for Flares 0.08 0.02
Operating Above Their Smokeless
Capacity...............................
-------------------------------
Total............................... 7.01 1.48
------------------------------------------------------------------------
2. PRDs
The HON defines several terms applicable to process vents at 40 CFR
63.101 and 40 CFR 63.107; similarly, P&R I defines several terms
applicable to process vents at 40 CFR 63.482. The current HON
definition of ``process vent'' excludes a ``relief valve discharge,''
(see 40 CFR 63.107(h)(1)) and the term ``process vent'' in P&R I at 40
CFR 63.482 excludes ``pressure releases.'' Instead, these MACT
standards in the HON and P&R I recognize HON relief valve discharges
and P&R I pressure releases to be the result of malfunctions. The
acronym ``PRD'' means pressure relief device and is common vernacular
to describe the variety of devices regulated as pressure relief valves
(to provide clarity, see the end of this section for our proposed
revision to the definition of ``pressure relief device'' for the HON
and P&R I, our proposed definition of ``relief valve'' for the HON and
P&R I, and our proposal to add a definition in P&R II for ``pressure
relief device''). PRDs are designed to remain closed during normal
operation. Typically, the Agency considers PRD releases as the result
of an overpressure in the system caused by operator error, a
malfunction such as a power failure or equipment failure, or other
unexpected cause that results in immediate venting of gas from process
equipment to avoid safety hazards or equipment damage. The discussion
that follows within this section of the preamble primarily focuses on
the HON and P&R I because any release of HAP to the atmosphere from a
P&R II PRD should already be accounted for when determining compliance
with the production-based emission rate MACT standard (e.g., pounds HAP
per million pounds BLR or WSR produced).
The HON and P&R I currently regulate PRDs when they are seated
through equipment leak provisions that are applied only after the
pressure release event occurs (i.e., conduct monitoring with EPA Method
21 of appendix A-7 to 40 CFR part 60 after each pressure release using
a leak definition of 500 ppm); however, these provisions do not apply
to an emissions release from a PRD. In addition, the HON and P&R I
follow the EPA's pre-2008 practice of exempting SSM events from
otherwise applicable emission standards. Consequently, with PRD
releases treated as unplanned, nonroutine, and the result of
malfunctions, the HON and P&R I did not restrict PRD releases to the
atmosphere but instead treated them in the same manner as malfunctions
subject to the SSM exemption provision. In Sierra Club v. EPA, 551 F.3d
1019 (D.C. Cir. 2008), the Court determined that the SSM exemption
violates the CAA. We have previously explained the relationship between
this ruling and PRDs in other rulemakings revising section 112
standards (see, e.g., 85 FR 6067, February 4, 2020, and 85 FR 40386,
July 6, 2020). Section III.E.1 of this preamble contains additional
discussions on the removal of the SSM exemption provision for the SOCMI
and P&R I source categories. As a result, we evaluated the MACT
standards in the HON and P&R I for PRD HAP releases to the atmosphere
to ensure a standard continuously applies during these malfunction
events, consistent with the Sierra Club decision.
CAA section 112(d)(1) specifies that the EPA may ``distinguish
among classes, types, and sizes of sources'' when establishing
standards. (In establishing standards under CAA section 112(d), the EPA
may ``distinguish among classes, types, and sizes of sources within a
category or sub-category.'' CAA section 112(d)(1). See Sierra Club v.
EPA, 479 F.3d 875, 885 (D.C. Cir. 2007)). We are proposing two
subcategories of PRDs for the MACT standard in the HON and P&R I to
distinguish between classes of PRDs: (1) PRDs designed to vent through
a closed-vent system to a control device or to a process, fuel gas
system, or drain system (referred to as PRDs that vent to a control
system); and (2) PRDs designed to vent to the atmosphere, if a release
were to occur. We are proposing to subcategorize PRDs by class because
of design differences between the numerous PRDs at HON and P&R I
facilities that vent to a control system and that vent to the
atmosphere. Currently, HON and P&R I facilities are required to
evaluate PRDs as part of their risk management and process safety
management programs. When implementing these programs, facilities
identify PRDs that they intend to control as compared to those they
elect not to control (and that have the potential to vent to the
atmosphere if a release were to occur). Facilities do not control
certain PRDs because of technical or site-specific safety
considerations, such as PRDs that release chemicals that could be
incompatible with vent streams in downstream controls.
[[Page 25156]]
We evaluated each subcategory of PRDs separately to ensure that a
standard continuously applies. Essentially, PRDs that vent to a control
system are already complying with the process vent standards and are,
thus, presumably, already appropriately controlled. However, PRDs that
vent to atmosphere do not meet the current continuous process vent
standards. Therefore, we examined how to regulate PRDs that vent to
atmosphere under CAA section 112(d)(2) and (3). CAA section 112(h)(1)
states that the Administrator may prescribe a work practice standard or
other requirements, consistent with the provisions of CAA sections
112(d) or (f), in those cases where, in the judgment of the
Administrator, it is not feasible to enforce an emission standard. CAA
section 112(h)(2)(B) further defines the term ``not feasible'' in this
context to apply when ``the application of measurement technology to a
particular class of sources is not practicable due to technological and
economic limitations.'' As detailed here, we identified as the MACT
level of control work practice standards to regulate PRDs that vent to
atmosphere under CAA section 112(h), and are proposing such work
practice standards at proposed 40 CFR 63.165(e) (for HON) and proposed
40 CFR 63.502(a)(1) and (a)(2) (which references 40 CFR 63.165, for P&R
I) that are intended to reduce the number of PRD releases and will
incentivize owners or operators to eliminate the causes of PRD releases
to the atmosphere.
No HON or P&R I facility is subject to numeric emission limits for
PRDs that vent to the atmosphere.\131\ Further, we do not believe it is
appropriate to subject PRDs that vent to the atmosphere to numeric
emission limits due to technological and economical limitations that
make it impracticable to measure emissions from such PRDs. CAA section
112(h)(1) states that the EPA may prescribe a work practice standard or
other requirement, consistent with the provisions of CAA sections
112(d) or (f), in those cases where, in the judgment of the
Administrator, it is not feasible to enforce an emission standard. CAA
section 112(h)(2)(B) further defines the term ``not feasible'' in this
context as meaning that ``the application of measurement technology to
a particular class of sources is not practicable due to technological
and economic limitations.'' We consider it appropriate to establish a
work practice standard for PRDs that vent to atmosphere as provided in
CAA section 112(h), because the application of a measurement
methodology for PRDs that vent to atmosphere is not practicable due to
technological and economic limitations. First, it is not practicable to
use a measurement methodology for PRD releases that vent to atmosphere.
PRDs are designed to remain closed during normal operations and release
emissions only during nonroutine and unplanned events, and the venting
time can be very short and may vary widely in composition and flow
rate. These unique event characteristics make it infeasible to collect
a grab sample of the gases when a PRD release occurs, and a single grab
sample would also likely not account for potential variation in vent
gas composition. Additionally, it would not be cost-effective to
construct an appropriate conveyance and install and operate continuous
monitoring systems for each individual PRD that vents to atmosphere in
order to attempt to quantitatively measure a release event that may
occur only a few times in a 3-year period. (See U.S. Sugar Corp. v.
EPA, 830 F.3d 579, 664-67 (2016).) Further, we have not identified any
available, technically feasible CEMS that can accurately determine a
mass release quantity of VOC or HAP given the flow, composition, and
composition variability of potential PRD releases that vent to the
atmosphere from CMPUs or EPPUs. Rather, we have identified only
monitoring systems capable of alerting an owner or operator when a PRD
release occurs. Consequently, we have concluded that it is appropriate
to establish a work practice standard for PRDs that vent to the
atmosphere as provided in CAA section 112(h).
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\131\ As previously mentioned, P&R II is different from the HON
and P&R I because P&R II 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, P&R II does not
exclude PRD releases from its production-based emission rate MACT
standard.
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We also reviewed information about HON and P&R I facilities to
determine how the best performers are minimizing emissions from PRDs
that vent to the atmosphere. We first reviewed the requirements in the
EPA's Chemical Accident Prevention Provisions (40 CFR part 68) and
Occupational Safety and Health Administration's (OSHA) Process Safety
Management rule (29 CFR 1910.119). These rules focus on planning for
and minimizing or preventing scenarios which would result in releases
of chemicals. For example, as stated in Appendix C to the OSHA rule,
``Process safety management is the proactive identification, evaluation
and mitigation or prevention of chemical releases that could occur as a
result of failures in process, procedures or equipment.'' The rules are
applicable to any equipment in the process, and relief valves are
identified in each rule as an applicable source to evaluate. The EPA
and OSHA rules have similar requirements, except that the applicability
determinations are unique to each rule. Owners or operators are subject
to the EPA's Chemical Accident Prevention Provisions at 40 CFR part 68
if a process has more than a threshold quantity of a regulated
substance. Regulated substances and their thresholds are listed at 40
CFR 68.130. Owners or operators are subject to OSHA's Process Safety
Management rule at 29 CFR 1910.119 if a process involves either a
chemical that is at or above specified threshold quantities (listed in
appendix A to 29 CFR 1910.119) or a Category 1 flammable gas (as
defined in 29 CFR 1910.1200(c)) or flammable liquid with a flashpoint
below 100 degrees Fahrenheit. HON and P&R I facilities may be subject
to the Chemical Accident Prevention Provisions rule, as identified in
their title V permit (40 CFR 68.215 requires permits to list part 68 as
an applicable requirement, if subject). As a result, we further
reviewed this rule for consideration in developing the work practice
standard.
The EPA's Chemical Accident Prevention Provisions require a
prevention program. Facilities subject to the HON or P&R I would fall
under prevention program 3. Prevention program 3 includes the
following: Documentation of process safety information, conducting a
hazard analysis, documentation of operating procedures, employee
training, on-going maintenance, and incident investigations. The
process safety information documented must include information
pertaining to the hazards of the regulated substances in the process,
the technology of the process, and the process equipment (including
relief valves). When conducting the hazard analysis, facilities must
identify, evaluate, and control the hazards in the process; controls
may consider the application of detection methodologies (e.g., process
monitoring and control instrumentation) to provide early warning of
releases. The operating procedures must address multiple operating
scenarios (e.g., normal operations, startup, emergency shutdown) and
provide instructions for safely conducting process activities.
Conducting the hazard analysis and
[[Page 25157]]
documenting operating procedures are similar to prevention measures,
discussed below, though we note a specific number of measures or
controls is not specified for the program 3 prevention program.
Incident investigations must document the factors that contributed to
an incident and any resolutions and corrective actions (incident
investigations are consistent with root cause analysis and corrective
action, discussed below). Facilities are also required to document this
information in a Risk Management Plan that must be updated at least
every 5 years.
Next, we considered that some companies operating HON and P&R I
facilities also own and operate petroleum refineries and may have
established company-wide best practices as a result of specific state
and federal requirements. For example, petroleum refineries and
chemical plants located in certain counties in California are subject
to and complying with specific requirements for PRDs such as the Bay
Area Air Quality Management District (BAAQMD) Rule 8-28-304 and South
Coast Air Quality Management District (SCAQMD) Rule 1173. The BAAQMD
rule requires implementation of three prevention measures, and both
rules require root cause analysis and corrective action for certain
PRDs. These rules also formed the basis of the work practice standards
promulgated at 40 CFR 63.648(j) for PRD releases at petroleum
refineries in the Petroleum Refinery Sector RTR performed by the EPA
(80 FR 75178, December 1, 2015).
Considering our review of the EPA's Chemical Accident Prevention
Provisions and company-wide best practices that HON and P&R I
facilities may have implemented, we expect that the best performing HON
and P&R I facilities have implemented a program for PRDs that vent to
the atmosphere 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.
In fact, we confirmed this to be true for HON facilities based on
facility responses to our CAA section 114 request. We used this
information as the basis of the work practice standards that we are
proposing at 40 CFR 63.165(e) (for HON) and 40 CFR 63.502(a)(1) and (2)
(which references 40 CFR 63.165, for P&R I). Examples of prevention
measures include the following: Flow indicators, level indicators,
temperature indicators, pressure indicators, routine inspection and
maintenance programs, operator training, inherently safer designs,
safety instrumentation systems, deluge systems, and staged relief
systems where the initial PRD discharges to a control system.
We are also proposing a limit on the number of PRD releases that
can take place within a 3-yr period. Any PRD releases in excess of the
limit would result in a deviation from the work practice standard for
PRDs that vent to the atmosphere. We believe setting criteria to
determine a deviation is necessary for the work practice to be
effective. We considered limits on the number of PRD releases in both
3- and 5-year periods. Based on a Monte Carlo analysis of random rare
events (as conducted for the Petroleum Refinery Sector rule \132\), we
note that it is quite likely to have two or three events in a 5-year
period when a long time horizon (e.g., 20 years) is considered.
Therefore, we are proposing to limit the number of PRD releases from a
single PRD to either one, two, or three (depending on the root cause)
in a 3-year period as the basis of a deviation from the work practice
standard. We are proposing that it is a deviation from the work
practice standard if a single PRD that vents to atmosphere has two
releases within a 3-year period due to the same root cause. We believe
that this provision will help ensure that root cause/corrective actions
are conducted effectively. Otherwise, we are proposing that it is a
deviation from the work practice standard if a single PRD that vents to
the atmosphere has three releases within a 3-year period for any
reason. In addition, we are proposing that any PRD release for which
the root cause was determined to be operator error or poor maintenance
is a deviation from the work practice standard. Refer to proposed 40
CFR 63.165(e)(3)(v) (for HON) and proposed 40 CFR 63.502(a)(1) and (2)
(which references 40 CFR 63.165, for P&R I) for these proposed
provisions. Based on our cost assumptions, the nationwide capital cost
for complying with the PRD work practice requirements for the HON is
$13.7 million and the annualized capital costs is $7.1 million; and for
P&R I is $0.41 million and the annualized capital costs is $0.12
million.
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\132\ See 80 FR 75217, December 1, 2015.
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In addition, we believe that it is appropriate to exclude certain
types of PRDs that have very low/no potential to emit based on their
type of service, size, and/or pressure from the proposed work practice
standard for PRD releases that vent to atmosphere, provided they are
subject to other continuously applicable emission standards. Both the
Chemical Accident Prevention Provisions and the California petroleum
refinery PRD rules also exempt or impose simpler requirements for
certain PRDs. We are proposing at 40 CFR 63.165(e)(5) (for HON) and 40
CFR 63.502(a)(1) and (2) (which references 40 CFR 63.165, for P&R I)
that the following types of PRDs would not be subject to the work
practice standard for PRDs that vent to the atmosphere, but instead
would be covered by other continuously applicable emission
standards:\133\ (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
closed vent system to a control device or back into the process, to the
fuel gas system, or to a drain system. Each of the types of PRDs that
we are proposing would not be subject to the work practice standard are
discussed in greater detail here. With regard to PRDs in heavy liquid
service, any HAP release to the atmosphere from a PRD in heavy liquid
service would have a visual indication of a leak and any repairs to the
valve would have to be further inspected and, if necessary, repaired
under the existing equipment leak provisions. Therefore, we are
proposing that PRDs in heavy liquid service need not be additionally
subject to the work practice standard. In addition, we are proposing
that PRDs designed solely to release due to liquid thermal expansion
would not be subject to the work practice standard. We expect that
releases from these thermal relief valves would be insignificant.
Finally, we are also proposing that pilot-operated PRDs (where
emissions can be released to the atmosphere through a pilot discharge
vent) and balanced bellow PRDs (where emissions can be released to the
atmosphere through a bonnet vent) would not be subject to the work
practice standard, if the primary release valve associated with the
pilot-operated or balanced bellows PRD is vented through a closed vent
system to a control device or back into the process, to the fuel gas
system, or to a drain system. Pilot-operated and balanced bellows PRDs
are primarily used for pressure relief when the back pressure of the
discharge vent may be high or variable. Conventional PRDs act on a
differential pressure between the process gas and the discharge vent.
If the discharge vent pressure increases, the vessel pressure at which
the PRD will open increases, potentially leading
[[Page 25158]]
to vessel over-pressurization that could cause vessel failure. Balanced
bellows PRDs use a bellow to shield the pressure relief stem and top
portion of the valve seat from the discharge vent pressure. A balanced
bellows PRD will not discharge gas to the atmosphere during a release
event, except for leaks through the bonnet vent due to bellows failure
or fatigue. Pilot-operated PRDs use a small pilot safety valve that
discharges to the atmosphere to effect actuation of the primary valve
or piston, which then discharges to a control system. Balanced bellows
or pilot operated PRDs are considered a reasonable and necessary means
to safely control the primary PRD release.
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\133\ Pursuant to 40 CFR 63.165(a), each pressure relief device
in organic HAP gas or vapor service must continue to be operated
with an instrument reading of less than 500 ppm above background.
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For all PRDs in organic HAP service, owners or operators would
still be required to comply with the LDAR provisions, as they are
currently applicable. Therefore, all PRDs that vent to the atmosphere
would still perform LDAR to ensure the PRD properly reseats if a
release does occur, and PRDs that vent to control systems would still
be exempt from LDAR requirements given that if a release were to occur
from this specific class of PRDs, it would vent to a closed vent system
and control device.
Finally, to ensure compliance with the proposed work practice
standard for PRDs that vent to the atmosphere, we are also proposing at
40 CFR 63.165(e)(3) (for HON) and 40 CFR 63.502(a)(1) and (2) (which
references 40 CFR 63.165, for P&R I) that sources monitor these 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. Pressure release events from PRDs that
vent to the atmosphere have the potential to emit large quantities of
HAP. When a pressure release occurs, it is important to identify and
mitigate it as quickly as possible. For purposes of estimating the
costs of this requirement, we assumed that operators would install
electronic monitors on PRDs that vent to atmosphere to identify and
record the time and duration of each pressure release. However, we are
proposing to allow owners and operators to use a range of methods to
satisfy these requirements, including the use of a parameter monitoring
system (that may already be in place) on the process operating pressure
that is sufficient to indicate that a pressure release has occurred as
well as record the time and duration of that pressure release. Based on
our cost assumptions, the nationwide capital cost of installing these
electronic monitors for the HON is $3.1 million and the annualized
capital costs are $0.41 million; and for P&R I is $0.09 million and the
annualized capital costs are $0.01 million.
We also considered requiring all PRDs to be vented to a control
device as a beyond-the-floor requirement. While this would provide
additional emission reductions beyond those we are establishing as the
MACT floor, these reductions come at significant costs. For example,
the EPA estimated that the capital cost for controlling MON PRDs ranged
from $2,540 million to $5,070 million, and the annualized cost ranged
from $330 million to $660 million; and the incremental cost
effectiveness for requiring control of all MON PRDs that vent to the
atmosphere compared to the requirements described above exceeded $80
million per ton of HAP reduced (see 84 FR 69182, December 17, 2019).
Consequently, we conclude that this is not a cost-effective option.
The EPA is also proposing a requirement that any future installed
pilot-operated PRDs be the non-flowing type. As previously noted, under
CAA section 112(d)(1), the EPA may ``distinguish among classes, types,
and sizes of sources'' when establishing standards. There are two
designs of pilot-operated PRDs: flowing and non-flowing. When a flowing
pilot-operated PRD is actuated, the pilot discharge vent continuously
releases emissions; however, when a non-flowing pilot-operated PRD is
actuated, the pilot discharge vent does not vent continuously. Although
we expect pilot discharge vent emissions to be minimal for both
designs, limiting the future use of flowing pilot-operated PRDs is
warranted to prevent continuous release of emissions. Therefore, we are
proposing at 40 CFR 63.165(e)(8) (for HON) and 40 CFR 63.502(a)(1) and
(2) (which references 40 CFR 63.165, for P&R I) to require future
installation and operation of non-flowing pilot-operated PRDs at all
affected sources.
We are also proposing at 40 CFR 63.101 (for HON) and 40 CFR 63.482
(for P&R I) to clarify the definitions of ``pressure release,''
``pressure relief device,'' and ``relief valve.'' We are proposing to
define ``pressure release'' as 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. We are proposing to define ``pressure relief
device'' as 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.
We are proposing to define ``relief valve'' as a type of pressure
relief device that is designed to re-close after the pressure relief.
For clarity, we are also proposing for P&R II the same definition of
``pressure relief device'' that we are proposing for the HON and P&R I
because P&R II currently does not define this term. Although we are not
proposing for P&R II the same work practice standard for PRDs that vent
to the atmosphere that we are proposing for the HON and P&R I (because
as explained earlier in this section of the preamble any release of HAP
to the atmosphere from a P&R II pressure relief device should already
be accounted for when determining compliance with the production-based
emission rate MACT standard), we are proposing at 40 CFR 63.527(f) and
40 CFR 63.528(a)(6), that owners and operators keep records and report
the start and end time and date of each pressure release to the
atmosphere, an estimate of the mass quantity in pounds of each organic
HAP released, as well as any data, assumptions, and calculations used
to estimate of the mass quantity of each organic HAP released during
the event. These proposed records and reports for P&R II will assist
stakeholders in determining compliance with the production-based
emission rate MACT standard.
We solicit comment on all of the proposed revisions for PRDs. See
the document titled Review of Regulatory Alternatives for Certain Vent
Streams in the SOCMI Source Category that are Associated with Processes
Subject to HON and Processes Subject to Group I and Group II Polymers
and Resins NESHAPs, in the docket for this rulemaking for details on
the assumptions and methodologies used in this analysis.
3. Closed Vent System Containing Bypass Lines
For a closed-vent system containing bypass lines that can divert
the stream away from the APCD to the atmosphere, the HON and P&R I
require the owner or operator to either: (1) Install, maintain, and
operate a continuous parametric monitoring system for flow on the
bypass line that is capable of detecting whether a vent stream flow is
present at least once every 15 minutes or (2) secure the bypass line
valve in the
[[Page 25159]]
non-diverting position with a car-seal or a lock-and-key type
configuration. Under option (2), the owner or operator is also required
to inspect the seal or closure mechanism at least once per month to
verify the valve is maintained in the non-diverting position (e.g., see
40 CFR 63.114(d)(2) for more details). To ensure standards apply to HON
and P&R I emission sources at all times, we are proposing 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 P&R I) that an owner or operator may not
bypass the APCD at any time, that a bypass is a violation (see proposed
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 P&R I)), and owners and operators must estimate and
report the quantity of organic HAP released. We are proposing this
revision because bypassing an APCD could result in a release of
regulated organic HAP to the atmosphere and to be consistent with
Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), where the Court
determined that standards under CAA section 112(d) must provide for
compliance at all times. These requirements are consistent with CAA
section 112(d) controls and reflect the MACT floor. We did not identify
any additional options beyond this (i.e., beyond-the-floor options) for
minimizing emissions from closed-vent systems that are used to comply
with the emission standards. We are also proposing that the use of a
cap, blind flange, plug, or second valve on an OEL (following the
requirements specified in 40 CFR 60.482-6(a)(2), (b), and (c) or
following requirements codified in another regulation that are the same
as 40 CFR 60.482-6(a)(2), (b), and (c)) is sufficient to prevent a
bypass. We solicit comment on these proposed revisions.
4. Maintenance Activities
The EPA is proposing that emission limits apply at all times
consistent with Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008). We
recognize that this proposed change for vent streams that are
periodically discharged will affect certain maintenance activities such
as those that require equipment openings, and we consider maintenance
activities a separate class of startup and shutdown emissions because
there must be a point in time when the equipment can be opened, and any
remaining emissions are vented to the atmosphere. We also acknowledge
that it would require a significant effort to identify and characterize
each of these potential release points (e.g., for permitting purposes).
CAA section 112(h)(1) states that the Administrator may prescribe a
work practice standard or other requirements, consistent with the
provisions of CAA sections 112(d) or (f), in those cases where, in the
judgment of the Administrator, it is not feasible to enforce an
emission standard. We are proposing work practices instead of numeric
emission limits for maintenance activities because it is ``not feasible
to prescribe or enforce an emission standard'' for these emissions.
Maintenance activities are not ``emitted through a conveyance designed
and constructed to emit or capture such pollutant'' (see CAA section
112(h)(2)(A)) and it is not possible to characterize each of these
potential release points. The discussion that follows within this
section of the preamble primarily focuses on the HON and P&R I because
any release to the atmosphere from P&R II maintenance activities should
already be accounted for when determining compliance with the
production-based emission rate MACT standard (e.g., pounds HAP per
million pounds BLR or WSR produced).
a. Equipment Openings (Excluding Storage Vessel Degassing)
We reviewed state permit conditions and determined the best
performers' permits specify that they meet certain conditions before
they open equipment to the atmosphere. The conditions include
thresholds regarding the LEL and the mass of gas that may be emitted.
These requirements are consistent with CAA section 112(d) controls and
reflect the level of performance analogous to a MACT floor. Therefore,
we are proposing a work practice standard 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 P&R
I), that prior to opening process equipment to the atmosphere during
maintenance events, the equipment first be drained and purged to a
closed system so that the hydrocarbon content is less than or equal to
10 percent of the LEL. For those situations where 10-percent LEL cannot
be demonstrated, we are proposing at 40 CFR 63.113(k)(1)(ii) (for HON),
and at 40 CFR 63.485(x) and 40 CFR 63.487(i)(1)(ii) (for P&R I), that
the equipment may be opened and vented to the atmosphere if 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. We are proposing this 5 psig threshold to acknowledge that a
certain minimum pressure must exist for the flare header system (or
other similar control system) to operate properly. We are also
proposing at 40 CFR 63.113(k)(1)(iii) (for HON), and at 40 CFR
63.485(x) and 40 CFR 63.487(i)(1)(iii) (for P&R I), that equipment may
be opened when there is less than 50 pounds of VOC that may be emitted
to the atmosphere.
We also acknowledge that installing a blind flange to prepare
equipment for maintenance may be necessary and by doing so, the owner
or operator may not be able to meet the proposed maintenance vent
conditions mentioned above (e.g., a valve used to isolate the equipment
will not seat fully, so organic material may continually leak into the
isolated equipment). To limit the emissions during the blind flange
installation, we are proposing at 40 CFR 63.113(k)(1)(iv) (for HON),
and at 40 CFR 63.485(x) and 40 CFR 63.487(i)(1)(iv) (for P&R I),
depressurizing the equipment to 2 psig or less prior to equipment
opening and maintaining pressure of the equipment where purge gas
enters the equipment at or below 2 psig during the blind flange
installation. The low allowable pressure limit will reduce the amount
of process gas that will be released during the initial equipment
opening, and the ongoing 2 psig pressure requirement will limit the
purge gas rate. Together, these proposed provisions will limit the
emissions during blind flange installation and will result in
comparable emissions allowed under the proposed maintenance vent
conditions mentioned above. We expect these situations to be rare and
that the owner or operator would remedy the situation as soon as
practical (e.g., replace the isolation valve or valve seat during the
next turnaround in the example provided above). Therefore, we are only
proposing that this alternative maintenance vent limit be used under
those situations where the proposed primary limits (i.e., hydrocarbon
content is less than or equal to 10 percent of the LEL, pressure is
less than or equal to 5 psig, or VOC is less than 50 pounds) are not
achievable and blinding of the equipment is necessary. We did not
identify any additional options beyond those identified above (i.e.,
beyond-the-floor options) for controlling emissions from equipment
openings.
We expect that all HON and P&R I facilities already have standard
procedures in place when performing equipment openings (at the very
least for safety reasons). As such, the only costs incurred are for
recordkeeping
[[Page 25160]]
after each non-conforming event. We are proposing that owners or
operators document each circumstance under which the alternative
maintenance vent limit is used, providing an explanation as to why
other criteria could not be met prior to equipment blinding and an
estimate of the emissions that occurred during the equipment blinding
process. For the HON, we calculated the annual costs to be $94,250 per
year. For P&R I, we calculated the annual costs to be $8,650 per year.
We solicit comment on the proposed revisions related to maintenance
activities. For additional details and discussion, see the document
titled Review of Regulatory Alternatives for Certain Vent Streams in
the SOCMI Source Category that are Associated with Processes Subject to
HON and Processes Subject to Group I and Group II Polymers and Resins
NESHAPs, which is available in the docket for this rulemaking. As
previously mentioned in section III.C.3.b of this preamble, we are also
proposing these same maintenance vent standards for NSPS subpart IIIa,
NNNa, and RRRa under CAA section 111(b)(1)(B).
b. Storage Vessel Degassing
With the proposed removal of SSM requirements, a standard specific
to storage vessel degassing does not exist when storage vessels are
using control devices to comply with the requirements in 40 CFR
63.119(a)(2) (for HON) and 40 CFR 63.484(a) (for P&R I, which
references 40 CFR 63.119). We acknowledge that storage vessel degassing
is similar to maintenance vents (e.g., equipment openings) and that
there must be a point in time when the storage vessel can be opened and
any emissions vented to the atmosphere. We reviewed available data to
determine how the best performers are controlling storage vessel
degassing emissions.
We are aware of three regulations regarding storage vessel
degassing, two in the state of Texas and the third for the SCAQMD in
California. Texas has degassing provisions in the TAC \134\ and through
permit conditions,\135\ while Rule 1149 contains the SCAQMD degassing
provisions.\136\ 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.
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\134\ See 30 TAC Chapter 115, Subchapter F, Division 3,
available at https://texreg.sos.state.tx.us/public/readtac%24ext.ViewTAC?tac_view=5&ti=30&pt=1&ch=115&sch=F&div=3&rl=Y.
\135\ See https://www.tceq.texas.gov/assets/public/permitting/air/Guidance/NewSourceReview/mss/chem-mssdraftconditions.pdf.
\136\ See http://www.aqmd.gov/docs/default-source/rule-book/reg-xi/rule-1149.pdf.
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HON and P&R I facilities located in Texas are subject to the permit
conditions, but no HON or P&R I facility is subject to the SCAQMD rule.
Of the 207 currently operating HON facilities, 78 are in Texas (four of
which are collocated with P&R I processes). Of the 19 currently
operating P&R I facilities, 6 are in Texas (including the four
collocated with HON processes). Therefore, the Texas permit conditions
relying on storage vessel degassing until 10 percent of the LEL is
achieved reflect what the best performers have implemented for storage
vessel degassing, and we considered this information as the MACT floor
for both new and existing HON and P&R I sources.
We reviewed Texas permit condition 6 (applicable to floating roof
storage vessels) and permit condition 7 (applicable to fixed roof
storage vessels) for key information that could be implemented to form
the basis of a standard for storage vessel degassing. The Texas permit
conditions require control of degassing emissions for floating roof and
fixed roof storage vessels until the vapor space concentration is less
than 10 percent of the LEL. The permit conditions also specify that
facilities can also degas a storage vessel until they meet a VOC
concentration of 10,000 ppmv, but we do not consider 10,000 ppmv to be
equivalent to or as stringent as the compliance option to meet 10
percent of the LEL and are not including this as a compliance option.
We also do not expect the best performers would be using this
concentration for compliance because the Texas permit conditions allow
facilities to calibrate their LEL monitor using methane. Storage
vessels may be vented to the atmosphere once the storage vessel
degassing concentration threshold is met (i.e., less than 10 percent of
the LEL) and all standing liquid has been removed from the vessel to
the extent practicable. We are proposing that these requirements are
considered MACT floors for both new and existing HON and P&R I sources;
therefore, we are proposing these requirements at 40 CFR 63.119(a)(6)
(for HON) and 40 CFR 63.484(a) and (t) (which references 40 CFR 63.119,
for P&R I). Additionally, in petitions for reconsideration that the EPA
recently received on the MON, EMACT standards, the Petroleum Refinery
Sector rule, and OLD NESHAP, petitioners asserted that it is necessary
to make connections to a temporary control device to control the
floating roof storage vessel degassing emissions, which may require
opening the storage vessel to make these connections. While we do not
believe the current language precludes a facility from taking this
step, we are revising the standard to include related language for
clarity. Therefore, we are proposing that a floating roof storage
vessel may be opened prior to degassing to set up equipment (i.e., make
connections to a temporary control device), but this must be done in a
limited manner and must not actively purge the storage vessel while
connections are made.
We calculated the impacts due to controlling storage vessel
degassing emissions by evaluating the population of storage vessels
that are subject to control under 40 CFR 63.119(a)(2) (for HON) and 40
CFR 63.484(a) (for P&R I, which references 40 CFR 63.119), and not
located in Texas. Storage vessels regulated by the HON or P&R I in
Texas would already be subject to the degassing requirements, and there
would not be additional costs or emissions reductions for these
facilities. We estimated there are an average of four Group 1 HON
storage vessels per CMPU and two Group 1 P&R I storage vessels per
EPPU. We applied these counts to the number of HON and P&R I processes
that are not located in Texas, resulting in 1,580 HON storage vessels
and 26 P&R I storage vessels newly applicable to vessel degassing
requirements. Based on a review of facility responses to our CAA
section 114 request, most storage vessels are degassed an average of
once every 13 years. Using this average and the population of storage
vessels that are not in Texas, we estimated 122 HON storage vessel
degassing events and two P&R I storage vessel degassing events would be
newly subject to control each year. Controlling HON storage vessel
degassing would reduce HAP emissions by 106 tpy, with a total annual
cost of approximately $751,500. Controlling P&R I storage vessel
degassing would reduce HAP emissions by 1.70 tpy, with
[[Page 25161]]
a total annual cost of approximately $12,300. See the document titled
Degassing Cost and Emissions Impacts for Storage Vessels Located in the
SOCMI Source Category that are Associated with Processes Subject to HON
and for Storage Vessels Subject to Either the Group I Polymers and
Resins NESHAP or Group II Polymers and Resins NESHAP, which is
available in the docket for this rulemaking, for details on the
assumptions and methodologies used in this analysis. We also considered
options beyond-the-floor, but we did not identify and are not aware of
storage vessel degassing control provisions more stringent than those
discussed above and being proposed in this rule; therefore, no beyond-
the-floor option was evaluated.
c. Planned Routine Maintenance for Storage Vessels
Although the HON and P&R I currently allow owners and operators to
disconnect the fixed roof vessel vent from the closed vent system and
control device, fuel gas system, or process equipment for up to 240
hours per year during planned, routine maintenance (see 40 CFR
63.119(e)(3) through (5) (for HON) and 40 CFR 63.484(a) (for P&R I)),
we are proposing 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). The removal of the 240-hr
exemption provisions except for vessel breathing losses is based upon
our position that removal is needed to satisfy Sierra Club v. EPA, 551
F.3d 1019 (D.C. Cir. 2008). These requirements are consistent with CAA
section 112(d) controls and reflect the MACT floor, as all working loss
emissions from storage vessels would be controlled during these
periods, ensuring a CAA section 112 standard is in place at this time.
We note that in 2018, the EPA finalized these same work practice
standards for the Amino/Phenolic Resins NESHAP (83 FR 51842, October
15, 2018). To evaluate the impacts of this proposed change to the HON
and P&R I, we assumed owners and operators would install a secondary
control device system (to control emissions from vessels during periods
of planned routine maintenance of the primary control device) and that
activated carbon canisters would be chosen as the method of control.
Based on vendor quotes, we determined that the total capital cost of a
55-gallon activated carbon drum with two connections, including piping
and duct work, is approximately $1,040. Following the guidelines of the
EPA's Seventh Edition OAQPS Control Cost Manual,\137\ we estimate that
the annual cost per CMPU or EPPU is $180. We also used information
about fixed roof storage vessels (including stored materials) that
industry provided to EPA in response to our CAA section 114 request
(see section II.C of this preamble). We estimate that there could be up
to 4 fixed roof storage vessels per CMPU requiring emissions control
under the HON. We multiplied this estimate (4) by the total HON
processes nationwide (634) and approximated that there are 2,536 fixed
roof storage vessels requiring emissions control under the HON
nationwide. For P&R I, we assumed that each P&R I facility has two
fixed roof storage vessels per EPPU that are subject to control.\138\
We also assumed that each facility has one P&R process. Using these
assumptions, we approximated that there are 38 fixed roof storage
vessels requiring emissions control under P&R I nationwide. We then
estimated that the highest amount of HAP emissions that would be
expected to occur from a HON or P&R I fixed roof storage vessel during
the 240 hours of planned routine maintenance would be 19.3 pounds, if
the emissions are not controlled. These emissions were based on the
largest vessel capacity and highest vapor pressure material stored in a
vessel that was reported in response to our CAA section 114 request,
and estimated using the emission estimation procedures from Chapter 7
of EPA's Compilation Of Air Pollutant Emission Factors,\139\ assuming
that only breathing losses would occur during this period. We assumed
that activated carbon canisters would achieve a 95 percent reduction in
HAP emissions, which would reduce emissions per vessel by 18.3 lbs HAP.
Based on our cost and emissions assumptions, the nationwide capital
cost for removal of the 240-hr exemption provisions (except for vessel
breathing losses) for the HON is $2.64 million and the annualized
capital costs is $0.46 million; and for P&R I is $0.04 million and the
annualized capital costs is about $0.01 million. See the document
titled Cost and Emissions Impacts for 240 Hour Planned Routine
Maintenance Work Practice Standard on Storage Vessels Located in the
SOCMI Source Category that are Associated with Processes Subject to HON
and for Storage Vessels Subject to the Group I Polymers and Resins
NESHAP, which is available in the docket for this rulemaking, for
details on the assumptions and methodologies used in this analysis.
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\137\ Air Pollution Control Cost Manual--Section 3: VOC
Controls; Section 3.1: VOC Recapture Controls, Carbon Adsorbers
Calculation Spreadsheet. Retrieved from https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution. October 2018.
\138\ This assumption is based on the median between four and
zero because our HON average is four, and the one facility that
received the CAA section 114 request and is subject to both the HON
and P&R I, reported zero Group 1 storage vessels subject to P&R I.
\139\ 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.
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As a beyond-the-floor control option, we considered requiring
owners and operators to also control breathing losses from storage
vessels during periods of planned routine maintenance of the emission
control system. However, this option is expected to be not cost
effective. For example, the EPA estimated a cost of $62,400 per ton of
HAP emissions reduced in their analysis conducted for this same option
in the Amino/Phenolic Resins NESHAP (82 FR 40103, August 24, 2017).
5. Dioxins and Furans Emission Limits
The HON, P&R I, and P&R II do not currently regulate emissions of
polychlorinated dibenzo-p-dioxins (dioxins) and polychlorinated
dibenzofurans (furans). Dioxins and furans can be formed when
chlorinated compounds are present and combusted in, for example, a
thermal oxidizer. HON facilities that release dioxins and furans
include those that manufacture chlorinated SOCMI chemicals (e.g.,
chloroform, chloroprene, ethylene dichloride, methyl chloride,
trichloroethylene, vinyl chloride). While the HON has 207 facilities
and 634 CMPUs, we estimated that at least 18 HON facilities and 34
CMPUs manufacture these chlorinated compounds and would have emissions
of dioxins and furans. As neoprene production facilities and
epichlorohydrin elastomer facilities in P&R I use, produce, or emit
chlorinated chemicals and all P&R II facilities use epichlorohydrin as
a feedstock, they can also produce and emit dioxins and furans through
combustion controls. Since dioxins and furans are currently an
unregulated pollutant in these NESHAP, we are proposing dioxins and
furans MACT standards under CAA section 112(d)(2) and (3) for the HON,
P&R I, and P&R II.
The MACT standard setting process starts with determining the level
of HAP emissions limitation that is currently achieved by the best-
controlled similar source (for new source standards) or by the average
of the best-performing
[[Page 25162]]
sources (for existing source standards). Specifically for categories
with 30 or more sources, the MACT floor for existing sources must be at
least as stringent as the average emissions limitation achieved by the
best performing 12 percent of existing sources for which the EPA has
emissions information. For source categories with fewer than 30
sources, the MACT floor for existing sources is the average emission
limitation achieved by the best performing five sources. See CAA
sections 112(d)(2)-(3)(A) and (B). We applied the upper prediction
limit (UPL) and information on the RDL to calculate the MACT floor.
Once the UPL is calculated for new sources and existing sources, the
UPL must be compared to the three times the RDL value as a final step
to assess variability. If the three times the RDL value is greater than
the UPL, then three times the RDL is selected as the MACT floor
emission level.
Dioxins and furans stack test data are available for nine HON
facilities, and we assessed this data to conduct our MACT analyses and
develop the emission limits for the HON sources. Multiple stack tests
included values below the detection level for certain dioxins and
furans congeners. Therefore, we evaluated the RDL and calculated a
three times the RDL value of 0.054 ng/dscm at 3 percent oxygen (toxic
equivalency basis). Since the HON has well over 30 sources (i.e., 634
CMPUs), we calculated the existing source UPL using data from the top
two facilities (i.e., nine times 12 percent rounds up to two) and
calculated the new source UPL using data from the best performer. The
existing source UPL was calculated as 0.032 ng/dscm at 3 percent oxygen
(toxic equivalency basis) and the new source UPL equaled 0.031 ng/dscm
at 3 percent oxygen (toxic equivalency basis). For both existing
sources and new sources, the three times the RDL value for dioxins and
furans was greater than the calculated UPL. As such, we are proposing
at 40 CFR 63.113(a)(5) that the dioxins and furans emissions limit for
HON facilities is the three times the RDL value of 0.054 ng/dscm at 3
percent oxygen (toxic equivalency basis). To ensure compliance with
this limit, we are proposing performance testing requirements that
include the use of Method 23 of 40 CFR part 60, appendix A-7 at 40 CFR
63.116(h). We are also proposing a definition for the term ``dioxins
and furans'' at 40 CFR 63.101 to mean total tetra--through
octachlorinated dibenzo-p-dioxins and dibenzofurans. Finally, we are
proposing owners and operators comply with the same monitoring,
recordkeeping, and reporting requirements that are already required for
compliance with the current process vent standards. We did not identify
additional controls or perform a beyond-the-floor analysis for reducing
dioxins and furans emissions further because the proposed emission
limit is based on the detection limit of the method and represents the
lowest concentration of dioxins and furans that can be measured;
therefore no further reductions can be achieved that are measurable. We
solicit comment on the proposed standards for dioxins and furans for
the HON, P&R I, and P&R II. For details on the emission limit
calculations, see the document titled Dioxins and Furans MACT Floor in
the SOCMI Source Category for Processes Subject to HON and Processes
Subject to Group I and Group II Polymers and Resins NESHAPs, which is
available in the docket for this rulemaking.
Dioxins and furans stack test data are not available for P&R I and
P&R II facilities, and in our review of reported emissions inventories,
none of these facilities reported emissions of these pollutants from
these source categories. However, given that neoprene production
facilities and epichlorohydrin facilities in P&R I and all facilities
in P&R II have chlorinated chemicals that could be controlled with
combustion controls, the mechanism of formation of dioxins and furans
is the same as for HON sources controlling chlorinated SOCMI chemicals.
Given that no facilities are reporting emissions of these pollutants in
their inventories, we believe that the best performing sources that
would constitute the MACT floor would have emissions below three times
the RDL, which would be the lowest MACT emission standard the EPA would
set due to measurement limitations. Thus, we are proposing dioxins and
furans emissions limits for P&R I and P&R II facilities using,
producing, or emitting chlorinated chemicals that are the same as we
are proposing for the HON (i.e., 0.054 ng/dscm at 3 percent oxygen,
toxic equivalency basis). We are proposing the dioxins and furans
emission limit for P&R I at 40 CFR 63.485(x) (which points to 40 CFR
63.113(a)(5) for continuous front-end process vents) and 40 CFR
63.487(a)(3) and (b)(3) (for batch front-end process vents); and the
P&R II emission limit at 40 CFR 63.523(e) (for process vents associated
with each existing, new, or reconstructed affected 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). To ensure compliance
with the proposed limit, we are proposing performance testing
requirements that include the use of Method 23 of 40 CFR part 60,
appendix A-7 at 40 CFR 63.485(x) (which points to 40 CFR 63.116(h) for
P&R I continuous front-end process vents) and 40 CFR 63.490(g) (for P&R
I batch front-end process vents) and 63.525(m) (for P&R II sources). We
are also proposing a definition for the term ``dioxins and furans'' at
40 CFR 63.482 (for P&R I sources) and 40 CFR 63.522 (for P&R II
sources) to mean total tetra--through octachlorinated dibenzo-p-dioxins
and dibenzofurans. Finally, we are proposing owners and operators
comply with the same monitoring, recordkeeping, and reporting
requirements that are already required for compliance with the current
process vent standards. We solicit comment on the types of emission
controls used and stack test data for emissions of dioxins and furans
from the P&R I and P&R II source categories.
To evaluate the cost impacts of the proposed emissions limits, we
assumed select facilities would install a condenser prior to the
existing control device (e.g., thermal oxidizer) to remove chlorinated
compounds from the stream and prevent the formation of dioxins and
furans in the thermal oxidizer. Of the nine HON facilities with stack
test data, two facilities do not meet the proposed emission limit and
would need to install a condenser to reduce dioxins and furans
emissions.\140\ For the twelve HON facilities that do not have stack
test data available, we assumed that five facilities would not meet the
emission limits and would need to install a condenser to reduce their
emissions. We assumed the one P&R I facility with dioxins and furans
emissions in the risk modeling file and all five P&R II facilities
would need to install a condenser to meet the dioxins and furans
emissions limit. Based on our cost assumptions, the nationwide costs to
comply with the dioxins and furans emissions limits are $3.9 million in
capital costs and $2.3 million in annual costs for the HON; $0.56
million in capital costs and $0.33 million in annual costs for P&R I;
and $2.8 million
[[Page 25163]]
in capital costs and $1.6 million in annual costs for P&R II.
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\140\ Note that four facilities do not meet the dioxins and
furans emission limit in our dataset, however two of the four
facilities are subject to 40 CFR part 63, subpart HHHHHHH, and are
complying with a 0.051 ng/dscm at 3 percent oxygen, toxic
equivalency basis, limit for PVC-combined process vents and are
using the same control device for emissions from HON processes.
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We solicit comment on all aspects of the proposed emissions limits
for dioxins and furans. See the document titled Dioxins and Furans MACT
Floor in the SOCMI Source Category for Processes Subject to HON and
Processes Subject to Group I and Group II Polymers and Resins NESHAPs,
which is available in the docket for this rulemaking, for details on
the assumptions and methodologies used in the analyses.
6. Pressure Vessels
We are proposing new requirements for pressure vessels that are
associated with processes subject to the HON or P&R I. The EPA is
proposing to define pressure vessel at 40 CFR 63.101 (for HON) and 40
CFR 63.482 (for P&R I) 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.'' To
eliminate any ambiguity in applicability or control requirements, the
EPA is also proposing 40 CFR 63.101 (for HON) and 40 CFR 63.482 (for
P&R I) 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.\141\ This long-
standing exemption is ambiguous with respect to what ``without
emissions to the atmosphere'' means. For example, most pressure vessels
have relief devices that allow for venting when pressure exceeds
setpoints. In many cases, these vents are routed to control devices;
however, control devices are not completely effective (e.g., achieve 98
percent control), and therefore there are emissions to the atmosphere
from these pressure vessels, even if they are controlled. There are
also instances where other components in pressure systems may allow for
fugitive releases because of leaks from fittings or cooling systems.
All of these events arguably are ``emissions to the atmosphere'' and
therefore it is likely that even if this exemption were maintained,
owners and operators of pressure vessels would still have uncertainty
regarding whether or not they were subject to substantive requirements.
Therefore, the proposed revisions remove the ambiguity associated with
the exemption and set standards intended to limit emissions to the
atmosphere from pressure vessels. Given that we have seen large
emission events from PRDs on pressure vessels (e.g., a 155 tpy 1,3-
butadiene atmospheric PRD release was documented from a HON pressure
vessel in 2015),\142\ we are also proposing at 40 CFR 63.119(a)(7)(v)
and 40 CFR 63.484(t) that any atmospheric PRD release from a pressure
vessel is a deviation of the PRD work practice standards (see section
III.D.2 of this preamble for more information on the proposed PRD work
practice standards).
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\141\ We note that P&R II does not have a pressure vessel
exemption in its definition of storage tank (see 40 CR 63.522).
\142\ See the Appendix to the document titled Cost and Emissions
Impacts for Pressure Vessels Located in the SOCMI Source Category
that are Associated with Processes Subject to HON and for Pressure
Vessels Subject to the Group I Polymers and Resins NESHAP, which is
available in the docket for this rulemaking.
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We are proposing LDAR requirements at 40 CFR 63.119(a)(7) (for HON)
and 40 CFR 63.484(t) (for P&R I) that are based on similar no-
detectable emission requirements required for closed vent systems in
most chemical sector NESHAP. These requirements are consistent with CAA
section 112(d) controls and reflect the MACT floor. As such, these
proposed requirements 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 of 40 CFR part 60, Appendix A-7;
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). The proposed standards recognize that pressure vessels
can be designed with appropriate capture and containment systems for
leak interfaces and pressure vessel PRDs such that the owner or
operator can avoid ``willful'' deviations. We also did not identify any
additional options beyond those identified above (i.e., beyond-the-
floor options) for minimizing emissions to the atmosphere from pressure
vessels.
Based on facility responses to our CAA section 114 request, we
estimate that there could be up to one pressure vessel per every two
CMPUs for a total of 317 pressure vessels requiring emissions control
under the HON nationwide (1 pressure vessel per 2 CMPUs x 634 CMPUs =
317 pressure vessels). We also estimate that there are nine P&R I
facilities that each have one pressure vessel (for a total of nine
pressure vessels requiring emissions control under P&R I nationwide)
given that: (1) We are aware of three P&R I facilities within the
polybutadiene rubber source category that each have a pressure vessel,
(2) there are five P&R I facilities that make styrene butadiene rubber
and are therefore likely to each have one 1,3-butadiene pressure
vessel, and (3) we are aware of one other pressure vessel (storing EtO)
located at a P&R I facility producing epichlorohydrin elastomer. Using
information from a 2012 analysis that identified developments for
storage vessels at chemical manufacturing facilities and petroleum
refineries,\143\ we estimate a total HAP emission reduction of 244 tpy
for all affected pressure vessels associated with processes subject to
the HON and 6.9 tpy HAP for pressure vessels subject to P&R I; the
nationwide capital cost for the proposed pressure vessel LDAR
requirements for the HON is about $78,000 and the annualized capital
costs is $73,000, and for P&R I the nationwide capital cost is $2,200
and the annualized capital costs is about $2,000. See the document
titled Cost and Emissions Impacts for Pressure Vessels Located in the
SOCMI Source Category that are Associated with Processes Subject to HON
and for Pressure Vessels Subject to the Group I Polymers and Resins
NESHAP, which is available in the docket for this rulemaking, for
details on the assumptions and methodologies used in this analysis. We
solicit comment on the proposed revisions for pressure vessels.
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\143\ Randall, 2012. Memorandum from Randall, D., RTI
International to Parsons, N., EPA/OAQPS. Survey of Control
Technology for Storage Vessels and Analysis of Impacts for Storage
Vessel Control Options. January 20, 2012. EPA Docket No. EPA-HQ-OAR-
2010-0871.
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7. Surge Control Vessels and Bottoms Receivers
The HON and P&R I define a surge control vessel to mean feed drums,
recycle drums, and intermediate vessels. Surge control vessels are used
within a CMPU or an EPPU when in-process storage, mixing, or management
of flow rates or volumes is needed to assist in production of a
product. The HON and P&R I define a bottoms receiver as a tank that
collects distillation bottoms before the stream is sent for storage or
for further downstream processing. Surge control vessels and bottoms
receivers are not considered storage vessels under the HON and P&R I
because they are covered by the equipment leak provisions. Although
these emissions sources are regulated under the equipment leak
provisions (i.e., NESHAP subpart H), the equipment leak requirements
point back to the storage vessel requirements in NESHAP subpart G.
Owners and operators of surge
[[Page 25164]]
control vessels and bottoms receivers are required to comply with the
HON storage vessel requirements in NESHAP subpart G (i.e., use a
floating roof or route emissions to closed vent system and control to
get 95 percent control) provided the surge control vessel or bottoms
receiver meets certain capacity and vapor pressure requirements. For
HON and P&R I surge control vessels and bottoms receivers at existing
sources, storage vessel control requirements apply if the capacity is
between 75 m\3\ and 151 m\3\ and the MTVP is greater than or equal to
13.1 kPa, or the capacity is greater than or equal to 151 m\3\ and the
MTVP is greater than or equal to 5.2 kPa. For HON and P&R I surge
control vessels and bottoms receivers at new sources, storage vessel
control requirements apply if the capacity is between 38 m\3\ and 151
m\3\ and the MTVP is greater than or equal to 13.1 kPa, or the capacity
is greater than or equal to 151 m\3\ and the MTVP is greater than or
equal to 0.7 kPa. The HON and P&R I exclude all other surge control
vessels and bottoms receivers from emissions control requirements.
We are proposing at 40 CFR 63.170(b) (for HON) and 40 CFR 63.485(d)
(for P&R I) 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 (see section III.D.1 of this preamble); or reduce emissions of
total organic HAP or TOC by 98 percent by weight or to an exit
concentration of 20 ppmv, whichever is less stringent. These
requirements are consistent with CAA section 112(d) controls and
reflect the MACT floor.\144\ Emissions from surge control vessels and
bottoms receivers are characteristic of process vents, not emissions
from storage vessels. 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. We did not identify
any additional options beyond those identified above (i.e., beyond-the-
floor options) for controlling emissions from surge control vessels and
bottoms receivers. We solicit comment on the proposed revisions for
surge control vessels and bottoms receivers.
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\144\ They also represent the level of control found to be cost-
effective for process vents and that we are proposing for HON
process vents under technology review in section III.C.3 of this
preamble.
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8. Transfer Operations (for HON)
Generally, transfer operations refer to the equipment (e.g.,
transfer racks) that are used to transfer materials (primarily liquid
products) from the facility, typically from storage vessels, into
transport vehicles, portable cargo units, and marine vessels that are
used to carry the material to another site or location. The combination
of the transfer rack, storage vessel, connecting piping, and equipment
used/on the connecting piping are typically part of the process unit or
affected source in existing regulations. The HON regulates transfer
operations at 40 CFR 63.126 through 40 CFR 63.130. Transfer operations
are defined in the HON at 40 CFR 63.101 to mean the loading, into a
tank truck or railcar, of organic liquids that contain one or more of
the organic HAP listed in table 2 to NESHAP subpart F from a transfer
rack; and transfer operations do not include loading at an operating
pressure greater than 204.9 kPa. Transfer racks are also defined in the
HON at 40 CFR 63.101. Under the HON, transfer racks mean the collection
of loading arms and loading hoses, at a single loading rack, that are
assigned to a CMPU subject to NESHAP subpart F according to the
procedures specified in 40 CFR 63.100(h) and are used to fill tank
trucks and/or railcars with organic liquids that contain one or more of
the organic HAP listed in table 2 to NESHAP subpart F. A transfer rack
includes the associated pumps, meters, shutoff valves, relief valves,
and other piping and valves, but does not include: (1) Racks, arms, or
hoses that only transfer liquids containing organic HAP as impurities;
(2) racks, arms, or hoses that vapor balance during all loading
operations; or (3) racks transferring organic liquids that contain
organic HAP only as impurities.
In general, when the equipment and operations are physically
separate (i.e., do not share common piping, valves, and other
equipment), the transfer racks are considered separate transfer racks.
Transfer rack emissions depend on several factors, including the
physical and chemical characteristics of the liquid being loaded, the
quantity of material loaded, and the loading conditions. Primarily,
these characteristics boil down to the volatility (or vapor pressure)
and molecular weight of the liquid being transferred, the temperature
and pressure conditions of the transfer operation, the loading method
employed (e.g., submerged loading versus splash loading), and the
volume of material transferred. In addition, during the loading of
liquid into transport vehicles, VOC and HAP vapors present in the
transport vehicle are displaced by the liquid being loaded. The vapors
in the transport vehicle include either vapors generated as the liquid
is being loaded, and/or vapors remaining from residual commodity or
liquid from the previous load (if present). For uncontrolled
operations, transfer rack emissions typically occur at the loading
hatch or opening of the transport vehicle. Emissions can also occur
from leaks in the transport vehicle. The rate at which these VOC and
HAP are emitted varies depending on which type of transport vehicle is
being loaded (tank truck or railcar), whether the transport vehicle was
empty before filling or refilled while still containing a heel and
vapors, the physical and chemical characteristics of the liquid being
loaded, and the type of loading method used.
Owners and operators of each HON transfer rack that annually loads
greater than or equal to 0.65 million liters of liquid products that
contain organic HAP with a rack weighted average vapor pressure greater
than or equal to 10.3 kPa are required to equip each transfer rack 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, whichever is less stringent. The HON also allows multiple other
options to control emissions from applicable transfer racks, including:
use of a flare, or collecting emissions for use in the process, a fuel
gas system, or a vapor balance system. However, as previously
mentioned, the HON excludes transfer racks with an operating pressure
greater than 204.9 kPa from these requirements. While we recognize that
these high operating pressure transfer racks are likely being
controlled by owners and operators, the HON does not currently require
them to be controlled on the presupposition that transfer racks with an
operating pressure greater than 204.9 kPa do not leak emissions to the
atmosphere. We consider the lack of control requirements for transfer
racks with an operating pressure greater than 204.9 kPa to be a gap in
the current HON. As such, we are proposing to remove the 204.9 kPa
operating pressure exemption from the definition of transfer operations
at 40 CFR 63.101 on the premise that, just like pressure vessels (as
discussed in section III.D.6 of this preamble), these high operating
pressure transfer racks can have
[[Page 25165]]
emissions to the atmosphere. Considering this, owners and operators
would be required to equip each transfer rack with an operating
pressure greater than 204.9 kPa 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 parts per million by volume,
whichever is less stringent. These requirements are consistent with CAA
section 112(d) controls and reflect the MACT floor, and we did not
identify any additional options beyond this (i.e., beyond-the-floor
options) for controlling emissions from these transfer racks.
We anticipate that the proposed removal of the 204.9 kPa operating
pressure exemption from the definition of transfer operations would not
impose a cost increase because we believe that owners and operators are
already controlling emissions from transfer racks with an operating
pressure greater than 204.9 kPa. For example, as discussed in an EPA
published document regarding sources of EtO,\145\ EtO is normally
shipped in 38,000 and 76,000 liter (10,000 and 20,000 gallon) railroad
tank cars, which are normally loaded directly from plant storage
vessels. The transfer generally occurs at about 350 kPa. At most
facilities, displaced vapors from the filling of tank cars and storage
vessels are either recycled to the process or scrubbed prior to
incineration or flaring. When the vapors are scrubbed, the liquid
effluent from the scrubber is routed to the desorber for EtO recovery.
Emissions of EtO from storage and loading are assumed to be nearly zero
if either control approach is used. We solicit comment on the proposed
removal of the 204.9 kPa operating pressure exemption from the
definition of transfer operations and whether our assumption that these
types of transfer racks are already being controlled is reasonable.
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\145\ EPA. Locating And Estimating Air Emissions From Sources Of
Ethylene Oxide. September 1986. EPA-450/4-84-007L.
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9. Heat Exchange Systems (for P&R II)
P&R II currently does not regulate HAP emissions from heat exchange
systems. However, as previously discussed in sections III.B.2.a.iii and
III.C.1 of this preamble, the internal tubing material of a heat
exchanger can corrode or crack, allowing some process fluids to mix or
become entrained with the cooling water. Pollutants in the process
fluids may subsequently be released from the cooling water into the
atmosphere when the water is exposed to air (e.g., in a cooling tower
for closed-loop systems or trenches/ponds in a once-through system).
For this reason, we are proposing under CAA section 112(d)(2) and (3)
to include in P&R II the same LDAR program for heat exchange systems as
in the HON and P&R I, and we are proposing the same changes to this
LDAR program for P&R II that we are proposing in this action for the
HON and P&R I (see section III.C.1 of this preamble). Specifically, we
are proposing at 40 CFR 63.522 to revise the definition of ``affected
source'' to include heat exchange systems; and we are proposing the
same definition of ``heat exchange systems'' for P&R II that is already
used in the HON and P&R I to mean ``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.''
We reviewed publicly available air permits for the five facilities
subject to either the BLR or WSR standards in P&R II and found that
some of these facilities do have heat exchange systems. In reviewing
air permits, three of the five facilities subject to P&R II are
collocated with HON sources. Furthermore, we also anticipate that the
heat exchange systems used at these sources are small (<10,000 gallons
per minute) and would likely be sent to large, integrated cooling
towers subject to other NESHAP, like the HON, that are already
conducting water sampling at the cooling tower for leaks. Additionally,
we expect that most water used by heat exchange systems in P&R II
processes are likely from water jacketed reactors that either have
large pressure differentials (i.e., >35 kPa) between the cooling water
side and process side or have intervening cooling fluids between the
process and cooling water such that leaks of HAP would not occur in
heat exchange systems that would lead to air emissions. Given this, we
assumed that adding requirements for heat exchange systems would
already be accounted for in the HON or that heat exchange systems would
not be required to conduct such monitoring at P&R II sources because
they meet criteria that exempt heat exchange systems with no potential
for air emissions from the LDAR requirements. Thus, conducting an LDAR
program consistent with what is in the HON constitutes what the best
performers are doing and is the MACT floor level of control for P&R II
facilities. We note that even if a P&R II facility were to incur a cost
to implement a LDAR program for a heat exchange system, we would expect
this cost to be small (i.e., $4,300 in total capital investment and
$4,500/yr in total annualized cost) per the costs for a single heat
exchange system conducting El Paso monitoring and that this work
practice standard would be cost-effective for P&R II sources as a
beyond-the-floor control option. Thus, we are proposing that P&R II
sources comply with the same standard as we are proposing for HON and
P&R I heat exchange systems as part of our technology review (see
section III.C.1 of this preamble). For further information, see 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, which is available in the docket for this rulemaking.
We are proposing at 40 CFR 63.523(d) (for BLR manufacturers) and 40
CFR 63.524(c) (for WSR manufacturers) that owners and operators of each
affected source comply with the requirements of 40 CFR 63.104 for heat
exchange systems, except we are proposing to require 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 are also proposing
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). This would apply to both monitoring heat exchange systems and
individual heat exchangers by replacing the use of any 40 CFR part 136
water sampling method with the Modified El Paso Method and removing the
option that allows for use of a surrogate indicator of leaks. We are
also proposing 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 are proposing that none of these proposed
requirements would apply to heat exchange systems that have a maximum
cooling water flow rate of 10 gallons per minute or less. We solicit
[[Page 25166]]
comment on the proposed standards for heat exchange systems for P&R II.
10. WSR Sources and Equipment Leaks (for P&R II)
P&R II currently contains an alternative standard for WSR sources
that establishes a regulatory gap in the rule at 40 CFR 63.524(a) and
(b). The alternative standard allows owners and operators of WSR
sources to choose between complying with a production-based emission
limit for process vents, storage tanks, and wastewater systems, or the
requirements of NESHAP subpart H to control emissions from equipment
leaks. In other words, owners and operators of WSR sources are
currently not required to control emissions from all of their P&R II
emission sources.\146\ In the original proposed rulemaking, the EPA
stated that: ``Because no existing facility in the WSR source category
controls equipment leak emissions, the MACT floor for the equipment
leaks portion of the source represents an uncontrolled situation.''
\147\ Instead, the EPA promulgated the alternative standard for WSR
sources and said ``an alternative standard was specified that allows
facilities to implement the requirements of subpart H to control
emissions from equipment leaks. The alternative standard is much more
cost effective, and will result in a greater overall HAP emission
reduction. However, the alternative standard is not being required
because the cost was considered to be too high to justify requiring
more control than that achieved at the MACT floor. Section 112(d) of
the Clean Air Act requires standards to be set at a level no less
stringent than the MACT floor but requires consideration of the cost of
achieving further reductions before requiring reductions beyond the
MACT floor.'' \148\ We are proposing to address this regulatory gap by
requiring owners and operators of existing, new, or reconstructed
affected 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 proposed 40 CFR 63.524(a)(3) and
(b)(3)). We are also proposing to remove several introductory phrases
in P&R II that currently indicate the alternative standard is optional;
and instead, we are proposing to replace these phrases with text that
indicate the alternative standard is no longer optional, but required
(see proposed 40 CFR 63.525(e) through (i), 40 CFR 63.526(b) and (d),
and 40 CFR 63.527(b) through (d)). As previously mentioned, the EPA
determined that no WSR source was originally complying with the
requirements of NESHAP subpart H; instead, these WSR sources were
originally complying with the production-based emission limit for
process vents, storage tanks, and wastewater systems. However, a review
of the publicly available permits for the two WSR sources indicates
that they are currently complying with the equipment leak requirements
of the HON; thus, we believe the requirements are consistent with CAA
section 112(d) controls, reflect the MACT floor, and there are no
additional costs from this change. We also did not identify any
additional options beyond those identified above (i.e., beyond-the-
floor options) for reducing emissions from WSR sources. We solicit
comment on our proposal to require owners and operators of existing,
new, or reconstructed affected 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, and whether
our assumption that the affected WSR sources are already complying with
both standards is reasonable.
---------------------------------------------------------------------------
\146\ This alternative standard is not an option for BLR
sources; therefore, there is no regulatory gap in P&R II for BLR
sources. Instead, owners and operators of BLR sources are subject to
both a production-based emission limit for process vents, storage
tanks, and wastewater systems, and the requirements of NESHAP
subpart H to control emissions from equipment leaks (see 40 CFR
63.523).
\147\ See 59 FR 25387, May 16, 1994.
\148\ See 60 FR 12670, March 8, 1995.
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In addition, the definition of equipment leaks in P&R II at 40 CFR
63.522 excludes ``valves'' in the list of components; therefore, P&R II
currently does not regulate HAP emissions from leaking valves. We
believe this is a typographical error in P&R II and the EPA has always
intended to include valves as part of the equipment leaks LDAR program
requirements in P&R II. We note that in the original P&R II proposal
(see 59 FR 25387, May 16, 1994), the EPA referred to equipment leak
emission points using a phrase implying valve inclusivity (i.e., ``such
as pumps and valves''). Additionally, the BLR and WSR model plants used
to assess impacts of implementing the LDAR requirements in P&R II
included valve component counts; \149\ and no adverse comment was
received on this topic between proposal and final rulemaking for P&R
II. As previously mentioned, emissions of HAP from equipment leaks
occur in the form of gases or liquids that escape to the atmosphere
through many types of connection points (including valves). For this
reason, we are proposing under CAA section 112(d)(2) and (3) 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 P&R I 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. Specifically, our proposal would require owners or operators
to meet the control requirements for valves in NESHAP subpart H (see
section III.C.6.a of this preamble for a more detailed description of
the MACT standard for equipment leaks). A review of the publicly
available permits for P&R II sources indicates that P&R II facilities
are already complying with the equipment leak requirements of the HON
(which include LDAR requirements for valves), so we believe there are
no additional cost or emissions reduction from this proposed
typographical correction. We solicit comment on the proposed revisions
for equipment leaks from WSR sources in P&R II.
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\149\ See Appendix G of the document titled Hazardous Air
Pollutants From Epoxy Resins And Non-nylon Polyamide Resins
Production (Docket ID A-92-37, Item II-A-008).
---------------------------------------------------------------------------
E. What other actions are we proposing, and what is the rationale for
those actions?
In addition to the proposed actions on the CAA 111(b)(1)(B) and
112(d)(6) reviews discussed in section III.A of this preamble, we are
proposing to remove exemptions in the HON, P&R I, and P&R II from the
requirement to comply during periods of SSM; similarly, we are
proposing standards in NSPS subparts VVb, IIIa, NNNa, and RRRa that
apply at all times. We are also proposing to remove the affirmative
defense provisions from P&R I that were adopted in 2011. In addition,
we are proposing changes to the HON, P&R I, and P&R II recordkeeping
and reporting requirements to require the use of electronic reporting
of performance test reports and periodic reports; and we are proposing
similar standards in NSPS subparts VVb, IIIa, NNNa, and RRRa. We are
also proposing in the HON, P&R I, and P&R II to correct section
reference errors and make other minor editorial revisions. Finally, in
response to a petition for reconsideration, we are proposing to amend
NSPS subpart VVa; and although not part of the petition for
reconsideration, we are also proposing to clarify (in NSPS subpart VVa)
the
[[Page 25167]]
calibration drift assessment and correct the incorporations by
reference. Our rationale and proposed changes related to all of these
issues are discussed below.
1. SSM
In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C.
Cir. 2008), the United States Court of Appeals for the District of
Columbia Circuit (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 exemption
contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that
under section 302(k) of the CAA, 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) are null and void and any cross
reference to those provisions have no effect.
In March 2021, the EPA issued a rule \150\ to reflect the court
vacatur that revised the Part 63 General Provisions to remove the SSM
exemptions at 40 CFR 63.6(f)(1) and (h)(1). In this action, we are
proposing to eliminate references in the HON, P&R I, and P&R II to
these SSM exemptions in the General Provisions that are null and void
and are no longer printed in the CFR, remove any additional SSM
exemptions or references to SSM exemptions in the HON, P&R I, and P&R
II, and remove any cross-references in the HON, P&R I, and P&R II to
provisions in 40 CFR part 63 (General Provisions) that are unnecessary,
inappropriate or redundant in the absence of the SSM exemption.\151\
See section III.E.1.a of this preamble for our proposed amendments to
the HON, P&R I, and P&R II related to the SSM exemptions. The EPA has
attempted to ensure that the general provisions we are proposing to
override are inappropriate, unnecessary, or redundant in the absence of
the SSM exemption. We specifically seek comment on whether we have
successfully done so.
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\150\ U.S. EPA, Court Vacatur of Exemption From Emission
Standards During Periods of Startup, Shutdown, and Malfunction. (86
FR 13819, March 11, 2021).
\151\ We note that on April 21, 2011 (see 77 FR 22566), the EPA
finalized amendments to eliminate the SSM exemption in P&R I;
however, for consistency with the SSM related amendments that we are
proposing for the HON and P&R II, we are also proposing (as detailed
in this section of this preamble) additional amendments to P&R I
related to the SSM exemption that were not addressed in the April
21, 2011, P&R I rule.
---------------------------------------------------------------------------
Additionally, the EPA has determined the reasoning in the court's
decision in Sierra Club applies equally to CAA 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.\152\ Therefore, we are proposing standards in NSPS subparts VVb,
IIIa, NNNa, and RRRa that apply at all times, and more specifically
during periods of SSM, to match the proposed revised SSM provisions in
the HON, P&R I, and P&R II. The NSPS general provisions in 40 CFR
60.8(c) currently exempt non-opacity emission standards during periods
of SSM. We are proposing in NSPS subparts VVb, IIIa, NNNa, and RRRa
specific requirements \153\ that override the general provisions for
SSM. See section E.1.b of this preamble for our proposed standards
related to the SSM exemptions for NSPS subparts VVb, IIIa, NNNa, and
RRRa.
---------------------------------------------------------------------------
\152\ See, e.g., 88 FR 11556 (Feb. 23, 2023) (removing SSM
exemptions from NSPS for lead acid battery manufacturing plants); 87
FR 73708 (Dec. 1, 2022) (proposing to remove 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).
\153\ See proposed 40 CFR 60.482-1b, 40 CFR 60.612a, 40 CFR
60.662a, and 40 CFR 60.702a, respectively.
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a. Proposed Elimination of the SSM Exemption in the HON, P&R I, and P&R
II
We are proposing the elimination of the vacated exemption provision
and several revisions to Table 3 to subpart F of part 63 (the General
Provisions Applicability Table to subparts F, G, and H of 40 CFR part
63, hereafter referred to as the ``General Provisions table to HON''),
Table 1 to subpart U of part 63 (the General Provisions Applicability
Table to subpart U of 40 CFR part 63, hereafter referred to as the
``General Provisions table to P&R I''), and Table 1 to subpart W of
part 63 (the General Provisions Applicability Table to subpart W of 40
CFR part 63, hereafter referred to as the ``General Provisions table to
P&R II'') as is explained in more detail below. For example, we are
proposing to eliminate the incorporation of the General Provisions'
requirement that the source develop an SSM plan. We also are proposing
to eliminate and revise certain recordkeeping and reporting
requirements related to the SSM exemption. The EPA has attempted to
ensure that the provisions we are proposing to eliminate are
inappropriate, unnecessary, or redundant in the absence of the SSM
exemption.
For the HON and P&R II, we are proposing (as already required in
P&R I at 40 CFR 63.480(j)) that emissions from startup and shutdown
activities be included when determining if all the standards are being
met. As currently proposed in 40 CFR 63.102(e) and 40 CFR.525(j),
compliance with the emission limitations (including operating limits)
in the HON and P&R II is required ``at all times.'' We solicit comment
on whether owners and operators of affected sources subject to the HON
or P&R II will be able to comply with the standards during these times.
We also note that we are proposing standards for maintenance activities
that occur during periods of startup and shutdown (see section III.D.4
of this preamble). Emission reductions for storage vessel, process
vent, transfer rack, and wastewater operations (as well as other
emission sources) are typically achieved by routing vapors to an APCD
such as a flare, thermal oxidizer, or carbon adsorber. It is common
practice in this source category to start an APCD prior to startup of
the emissions source it is controlling, so the APCD would be operating
before emissions are routed to it. We expect APCDs would be operating
during startup and shutdown events in a manner consistent with normal
operating periods, and that these APCDs will be operated to maintain
and meet the monitoring parameter operating limits set during the
performance test.
Periods of startup, normal operations, and shutdown are all
predictable and routine aspects of a source's operations. Malfunctions,
in contrast, are neither predictable nor routine. Instead, they are, by
definition, sudden, infrequent, and not reasonably preventable failures
of emissions control, process, or monitoring equipment. (40 CFR 60.2
and 40 CFR 63.2) (definition of ``malfunction''). 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 D.C.
Circuit in U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016).
Therefore, the standards that apply during normal operation apply
during periods of malfunction.
Although no statutory language compels the EPA to set standards for
malfunctions, the EPA has the discretion to do so where feasible. For
example, in the Petroleum Refinery Sector RTR, the EMACT standards, and
[[Page 25168]]
the MON, the EPA established a work practice standard for unique types
of malfunction that result in releases from PRDs or emergency flaring
events because the EPA had information to determine that such work
practices reflected the level of control that applies to the best
performers (see 80 FR 75178, December 1, 2015, 85 FR 40386, July 6,
2020, and 85 FR 49084, August 12, 2020, respectively). The EPA will
consider whether circumstances warrant setting 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. We also encourage commenters to provide any such
information. These are discussed further in section III.D.1 and III.D.2
of this preamble.
We are also proposing the following revisions to the General
Provisions table to HON, the General Provisions table to P&R I, and the
General Provisions table to P&R II as detailed below.
i. General Duty
We are proposing to revise the General Provisions table to the HON
entry for 40 CFR 63.6(e) by adding a footnote to the ``yes'' entry in
column 2 to clarify that the row for the ``63.6(e)'' entry would no
longer be applicable beginning 3 years after publication of the final
rule in the Federal Register because the General Provisions table to
HON already contains other entries that breakdown the specific
paragraphs of 63.6(e) that are applicable to the HON. Some of the
language in section 63.6(e) is no longer necessary or appropriate in
light of the elimination of the SSM exemption. Section 63.6(e)(1)(i)
describes the general duty to minimize emissions and section 63.6(e)(3)
describes requirements for an SSM plan. We are proposing instead to add
general duty regulatory text at 40 CFR 63.102(f) (for HON) and 40 CFR
63.525(k) (for P&R II) that reflects the general duty to minimize
emissions while eliminating the reference to periods covered by an SSM
exemption. The current language in 40 CFR 63.6(e)(1)(i) characterizes
what the general duty entails during periods of SSM. With the
elimination of the SSM exemption, there is no need to differentiate
between normal operations, startup and shutdown, and malfunction events
in describing the general duty. We are also proposing to revise the
General Provisions table to P&R II entry for 40 CFR 63.6(e)(1)(i) by
adding a separate row for 40 CFR 63.6(e)(1)(i) and changing the ``yes''
in columns 2, 3, and 4 to a ``no'' in which 40 CFR 63.6(e)(1)(i) would
no longer be applicable beginning 3 years after publication of the
final rule in the Federal Register. Section 63.6(e)(1)(i) imposes
requirements that are not necessary with the elimination of the SSM
exemption or are redundant with the general duty requirement being
added at 40 CFR 63.102(f) and 40 CFR 63.525(k). Therefore, the language
the EPA is proposing for 40 CFR 63.102(f) and 40 CFR 63.525(k) does not
include the language from 40 CFR 63.6(e)(1). We note that the EPA
already added a similar general duty provision to P&R I at 40 CFR
63.483(a) (see 77 FR 22566, April 21, 2011); however, we are proposing
to correct a referencing error in the General Provisions table to P&R I
entry for 40 CFR 63.6(e)(1)(i) by changing ``Sec. 63.483(a)(1)'' to
``Sec. 63.483(a)''. We are also proposing revisions at 40 CFR
63.483(a) to be consistent with the general duty requirement we are
proposing to add to 40 CFR 63.102(f) and 40 CFR 63.525(k).We are also
proposing to revise the General Provisions table to HON entry for 40
CFR 63.6(e)(1)(ii) by changing the ``yes'' in column 2 to a ``no'' in
which 40 CFR 63.6(e)(1)(ii) would no longer be applicable beginning 3
years after publication of the final rule in the Federal Register. We
are proposing similar revisions for the General Provisions table to P&R
II by adding a separate row for 40 CFR 63.6(e)(1)(ii) and changing the
``yes'' in columns 2, 3, and 4 to a ``no'' in which 40 CFR
63.6(e)(1)(ii) would no longer be applicable beginning 3 years after
publication of the final rule in the Federal Register. We note that the
EPA already made a similar revision to the General Provisions table to
P&R I (see 77 FR 22566, April 21, 2011).
ii. SSM Plan
As noted in the previous paragraph, the proposed revisions to the
General Provisions table to the HON and the General Provisions table to
P&R II for 40 CFR 63.6(e) will also remove provisions that require an
SSM plan. We are proposing to revise the General Provisions table to
HON entries for 40 CFR 63.6(e)(3)(i), 63.6(e)(3)(i)(B), (C),
63.6(e)(3)(ii) and (vi) through (ix) by changing the ``yes'' in column
2 to a ``no'' in which these provisions would no longer be applicable
beginning 3 years after publication of the final rule in the Federal
Register. We are proposing similar revisions for the General Provisions
table to P&R II by adding a separate row for 40 CFR 63.6(e)(3) and
changing the ``yes'' in columns 2, 3, and 4 to a ``no'' in which 40 CFR
63.6(e)(3) would no longer be applicable beginning 3 years after
publication of the final rule in the Federal Register. We note that the
EPA already made a similar revision to the General Provisions table to
P&R I (see 77 FR 22566, April 21, 2011). Generally, the paragraphs
under 40 CFR 63.6(e)(3) require development of an SSM plan and specify
SSM recordkeeping and reporting requirements related to the SSM plan.
As noted, the EPA is proposing to remove the SSM exemptions. Therefore,
affected units are subject to an emission standard during such events.
The applicability of a standard during such events will ensure that
sources have ample incentive to plan for and achieve compliance and
thus the SSM plan requirements are no longer necessary.
iii. Compliance With Standards
We are proposing to clarify the comment in the General Provisions
table to HON entry for 40 CFR 63.6(f)(1) to include a reference to the
new proposed general duty requirements at 40 CFR 63.102(e). We are also
proposing to add a separate row for 40 CFR 63.7(a)(4) to the General
Provisions tables to the HON, P&R I, and P&R II to make 40 CFR
63.7(a)(4) applicable to each of these NESHAP for when an owner or
operator intends to assert a claim of force majeure.
iv. Performance Testing
We are proposing to revise the General Provisions table to HON
entry for 40 CFR 63.7(e)(1) by changing the ``yes'' in column 2 to a
``no'' in which 40 CFR 63.7(e)(1) would no longer be applicable
beginning 3 years after publication of the final rule in the Federal
Register. Section 63.7(e)(1) describes performance testing
requirements. We are proposing a similar revision to the General
Provisions table to P&R II entry for 40 CFR 63.7(e)(1) by changing the
``yes'' in columns 2, 3, and 4 to a ``no'' in which 40 CFR 63.7(e)(1)
would no longer be applicable beginning 3 years after publication of
the final rule in the Federal Register. We note that the EPA already
made a similar revision to the General Provisions table to P&R I (see
77 FR 22566, April 21, 2011). The EPA is instead proposing to add a
performance testing requirement at 40 CFR 63.103(b)(3)(ii) (for HON),
40 CFR 63.504(a)(1)(iii) (for P&R I), and 40 CFR 63.525(l) (for P&R
II). The performance testing requirements we are proposing differ from
the General Provisions performance testing provisions in several
respects. The regulatory text does not include the language in 40 CFR
63.7(e)(1) that restated the SSM
[[Page 25169]]
exemption and language that precluded startup and shutdown periods from
being considered ``representative'' for purposes of performance
testing. The proposed performance testing provisions will exclude
periods of startup or shutdown as representative conditions for
conducting performance testing. As in 40 CFR 63.7(e)(1), performance
tests conducted under this subpart should not be conducted during
malfunctions because conditions during malfunctions are often not
representative of normal operating conditions. The EPA is proposing to
add language that requires the owner or operator to 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. Section 63.7(e)(1) requires that
the owner or operator make such records ``as may be necessary to
determine the condition of the performance test'' available to the
Administrator upon request but does not specifically require the
information to be recorded. The regulatory text the EPA is proposing to
add to this provision builds on that requirement and makes explicit the
requirement to record the information.
v. Monitoring
We are proposing to revise the General Provisions tables to the HON
and P&R I entries for 40 CFR 63.8(c)(1)(i) and (iii) by changing the
``yes'' in column 2 to a ``no'' in which 40 CFR 63.8(c)(1)(i) and (iii)
would no longer be applicable beginning 3 years after publication of
the final rule in the Federal Register. We are proposing similar
revisions for the General Provisions table to P&R II entries for 40 CFR
63.8(c)(1)(i) and (iii) by changing the ``yes'' in columns 2, 3, and 4
to a ``no'' in which 40 CFR 63.8(c)(1)(i) and (iii) would no longer be
applicable beginning 3 years after publication of the final rule in the
Federal Register. The cross-references to the general duty and SSM plan
requirements in those subparagraphs are not necessary in light of other
requirements of 40 CFR 63.8 that require good air pollution control
practices (40 CFR 63.8(c)(1)).
vi. Reporting
We are proposing to revise the General Provisions table to the HON
entry for 40 CFR 63.10(d)(5) by changing the ``yes'' in column 2 to a
``no'' in which 40 CFR 63.10(d)(5) would no longer be applicable
beginning 3 years after publication of the final rule in the Federal
Register. We are proposing similar revisions for the General Provisions
table to P&R II entry for 40 CFR 63.10(d)(5) by changing the ``yes'' in
columns 2, 3, and 4 to a ``no'' in which 40 CFR 63.10(d)(5) would no
longer be applicable beginning 3 years after publication of the final
rule in the Federal Register. We note that the EPA already made a
similar revision to the General Provisions table to P&R I (see 77 FR
22566, April 21, 2011). Section 63.10(d)(5) describes the reporting
requirements for SSM. To replace the General Provisions reporting
requirement, the EPA is proposing to add reporting requirements to 40
CFR 63.152(c)(2)(ii)(F) (for HON), 40 CFR 63.506(e)(6)(iii)(C) (for P&R
I), and 40 CFR 63.528(a)(4) (for P&R II). The replacement language
differs from the General Provisions requirement in that it eliminates
periodic SSM reports as a stand-alone report. We are proposing language
that requires sources that fail to meet an applicable standard at any
time to report the information concerning such events in the periodic
report already required under the HON, P&R I, and P&R II. We are
proposing that the report must contain the cause of such events
(including unknown cause, if applicable), a list of the affected source
or equipment, an estimate of the quantity of each regulated pollutant
emitted over any emission limit, and a description of the method used
to estimate the emissions. Examples of such methods would include
product-loss calculations, mass balance calculations, measurements when
available, or engineering judgment based on known process parameters.
The EPA is proposing this requirement to ensure that there is adequate
information to determine compliance, to allow the EPA to determine the
severity of the failure to meet an applicable standard, and to provide
data that may document how the source met the general duty to minimize
emissions during a failure to meet an applicable standard.
We will no longer require owners or operators to determine whether
actions taken to correct a malfunction are consistent with an SSM plan,
because plans would no longer be required. The proposed amendments at
63.10(d)(5), therefore, eliminate the cross-reference to 40 CFR
63.10(d)(5)(i) that contains the description of the previously required
SSM report format and submittal schedule from this section. These
specifications are no longer necessary because the events will be
reported in otherwise required reports with similar format and
submittal requirements.
The proposed amendments at 63.10(d)(5) will also eliminate the
cross-reference to 40 CFR 63.10(d)(5)(ii). Section 63.10(d)(5)(ii)
describes an immediate report for startups, shutdown, and malfunctions
when a source failed to meet an applicable standard but did not follow
the SSM plan. We will no longer require owners or operators to report
when actions taken during a startup, shutdown, or malfunction were not
consistent with an SSM plan, because plans would no longer be required.
b. Proposal of NSPS Subparts VVb, IIIa, NNNa, and RRRa Without SSM
Exemptions
We are proposing standards in the NSPS subparts VVb, IIIa, NNNa,
and RRRa that apply at all times. For NSPS VVb, we are proposing that
the work practice standards will apply at all times, including during
SSM. For NSPS subparts IIIa, NNNa, and RRRa, these standards include
the performance standards when the affected facilities are operational
and work practice standards that will apply during periods of startup
and shutdown (including when maintenance and inspection activities are
being conducted). The NSPS general provisions in 40 CFR 60.8(c) contain
an exemption from non-opacity standards. Therefore, we are also
proposing in NSPS subparts VVb, IIIa, NNNa, and RRRa specific
requirements at 40 CFR 60.482-1b, 40 CFR 60.612a, 40 CFR 60.662a, and
40 CFR 60.702a, respectively that override the general provisions for
SSM. Accordingly, our proposed NSPS subparts VVb, IIIa, NNNa, and RRRa
would include standards that apply at all times, including during
periods of startup and shutdown.
Periods of startup, normal operations, and shutdown are all
predictable and routine aspects of a source's operations. Malfunctions,
in contrast, are neither predictable nor routine. Instead they are, by
definition, sudden, infrequent, and not reasonably preventable failures
of emissions control, process, or monitoring equipment. (40 CFR 60.2).
The EPA interprets CAA section 111 as not requiring emissions that
occur during periods of malfunction to be factored into development of
CAA section 111 standards. Nothing in CAA section 111 or in case law
requires that the EPA consider malfunctions when determining what
standards of performance reflect the degree of emission limitation
``achievable through the application of the best system of emission
reduction'' that the EPA determines is adequately demonstrated. While
the EPA accounts for variability in setting emissions standards, the
EPA is not required to treat a malfunction in
[[Page 25170]]
the same manner as the type of variation in performance that occurs
during routine operations of a source. A malfunction is a failure of
the source to perform in a ``normal or usual manner'' (40 CFR 60.2),
and no statutory language compels the EPA to consider such events in
setting section 111 standards of performance. The EPA's approach to
malfunctions when interpreting analogous language under CAA section 112
has been upheld as reasonable by the D.C. Circuit in U.S. Sugar Corp.
v. EPA, 830 F.3d 579, 606-610 (D.C. Cir. 2016) (affirming as reasonable
the EPA's approach to setting ``achievable'' standards under section
112 as measured by the ``best controlled similar source'' without
considering malfunctions, instead accounting for them in its
enforcement discretion).
Also, as previously discussed, although no statutory language
compels the EPA to set standards for malfunctions, the EPA has the
discretion to do so where feasible. The EPA is proposing to establish
work practice standards for unique types of malfunction that result in
releases from emergency flaring events because the EPA had information
to determine that such work practices reflected the level of control
that applies to the BSER. The EPA will consider whether circumstances
warrant setting standards for a particular type of malfunction in the
SOCMI NSPS rules, and, if so, whether the EPA has sufficient
information to identify the relevant best performing sources and
establish a standard for such malfunctions. We also encourage
commenters to provide any such information. These are discussed further
in sections III.D.1, III.C.3.b, and III.C.6.b of this preamble.
2. Affirmative Defense (Related to P&R I)
As part of one of the P&R I RTR rulemakings (see 77 FR 22566, April
21, 2011), the EPA included the ability to assert an affirmative
defense to civil penalties for violations caused by malfunctions (see
40 CFR 63.480(j)(4)) in an effort to create a system that incorporated
some flexibility, recognizing that there is a tension, inherent in many
types of air regulation, to ensure adequate compliance while
simultaneously recognizing that despite the most diligent of efforts,
emission standards may be violated under circumstances entirely beyond
the control of the source.\154\ Although the EPA recognized that its
case-by-case enforcement discretion provides sufficient flexibility in
these circumstances, it included the affirmative defense provision to
provide a more formalized approach and more regulatory clarity. See
Weyerhaeuser Co. v. Costle, 590 F.2d 1011, 1057-58 (D.C. Cir. 1978)
(holding that an informal case-by-case enforcement discretion approach
is adequate); but see Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73
(9th Cir. 1977) (requiring a more formalized approach to consideration
of ``upsets beyond the control of the permit holder.''). Under the
EPA's regulatory affirmative defense provisions, if a source could
demonstrate in a judicial or administrative proceeding that it had met
the requirements of the affirmative defense in the regulation, civil
penalties would not be assessed. However, the court vacated the
affirmative defense in one of the EPA's CAA section 112 regulations.
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 court found that the EPA
lacked authority to establish an affirmative defense for private civil
suits and held that under the CAA, the authority to determine civil
penalty amounts in such cases lies exclusively with the courts, not the
EPA. Specifically, the court found: ``As the language of the statute
makes clear, the courts determine, on a case-by-case basis, whether
civil penalties are `appropriate.''' See NRDC, 749 F.3d at 1063
(``[U]nder this statute, deciding whether penalties are `appropriate'
in a given private civil suit is a job for the courts, not
EPA.'').\155\ In light of NRDC, the EPA is proposing to remove all of
the regulatory affirmative defense provisions from P&R I at 40 CFR
480(j)(4) in its entirety and all other rule text that references these
provisions (i.e., the reference to ``Sec. 63.480(j)(4)'' in 40 CFR
63.506(b)(1)(i)(A) and (b)(1)(i)(B)). As explained above, if a source
is unable to comply with emissions standards as a result of a
malfunction, the EPA may use its case-by-case enforcement discretion to
provide flexibility, as appropriate. Further, as the court recognized,
in an EPA or citizen enforcement action, the court has the discretion
to consider any defense raised and determine whether penalties are
appropriate. Cf. NRDC, 749 F.3d at 1064 (arguments that violation was
caused by unavoidable technology failure can be made to the courts in
future civil cases when the issue arises). The same is true for the
presiding officer in EPA administrative enforcement actions.\156\
---------------------------------------------------------------------------
\154\ We note that the HON and P&R II do not include affirmative
defense rule text.
\155\ The court's reasoning in NRDC focuses on civil judicial
actions. The court noted that ``EPA's ability to determine whether
penalties should be assessed for CAA violations extends only to
administrative penalties, not to civil penalties imposed by a
court.'' Id.
\156\ Although the NRDC case does not address the EPA's
authority to establish an affirmative defense to penalties that are
available in administrative enforcement actions, we are not
including such an affirmative defense in the proposed rule. As
explained above, such an affirmative defense is not necessary.
Moreover, assessment of penalties for violations caused by
malfunctions in administrative proceedings and judicial proceedings
should be consistent. Cf. CAA section 113(e) (requiring both the
Administrator and the court to take specified criteria into account
when assessing penalties).
---------------------------------------------------------------------------
3. Electronic Reporting
The EPA is proposing that owners and operators of SOCMI processes
located at chemical plants submit electronic copies of required
performance test reports, flare management plans, and periodic reports
(including fenceline monitoring reports) through the EPA's Central Data
Exchange (CDX) using the Compliance and Emissions Data Reporting
Interface (CEDRI) (see proposed 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 P&R I), and 40 CFR 63.528(a) and (d) (for P&R II), 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)). We note that for NSPS VV, VVa, III, NNN, and RRR, we
are only proposing to change the format of the reporting requirements
to require electronic reporting (i.e., we are not proposing any new
data elements). A description of the electronic data submission process
is provided in the document titled Electronic Reporting Requirements
for New Source Performance Standards (NSPS) and National Emission
Standards for Hazardous Air Pollutants (NESHAP) Rules, available in the
docket for this action.
The proposed rules require that performance test results collected
using test methods that are supported by the
[[Page 25171]]
EPA's Electronic Reporting Tool (ERT) as listed on the ERT website
\157\ 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. Flare management plans would be uploaded as a PDF file.
---------------------------------------------------------------------------
\157\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------
For periodic reports (including fenceline monitoring reports), the
proposed rules require that owners and operators use an appropriate
spreadsheet template to submit information to CEDRI. A draft version of
the proposed templates for these reports is included in the docket for
this action.\158\ The EPA specifically requests comment on the content,
layout, and overall design of the templates. For NSPS subpart VV, VVa,
III, NNN, and RRR, we are proposing owners and operators begin using
the templates one year after the final rule is published in the Federal
Register or once the reporting template for the subpart has been
available on the CEDRI website for 1 year, whichever date is later. For
NSPS subparts VVb, IIIa, NNNa, and RRRa, we are proposing owners and
operators begin using the templates 60 days after the final rule is
published in the Federal Register or once the reporting template for
the subpart has been available on the CEDRI website for 1 year,
whichever date is later. For HON, P&R I, and P&R II, we are proposing
owners and operators begin using the templates for periodic reports
other than fenceline reports three years after the final rule is
published in the Federal Register, or once the reporting template for
the subpart has been available on the CEDRI website for 1 year,
whichever date is later. Owners and operators would begin using the
templates for fenceline monitoring reports starting when the first
fenceline monitoring report is due.
---------------------------------------------------------------------------
\158\ See Part_60_Subpart_VV_60.487(a)_Semiannual_Report.xlsx,
Part_60_Subpart_III_60.615_Semiannual_Report.xlsx,
Part_60_Subpart_NNN_60.665_Report.xlsx,
Part_60_Subpart_RRR_60.705_Report.xlsx,
Part_63_Subpart_G_63.152(c)_Periodic_Report.xlsx,
Part_63_Subpart_H_63.182(d)_Periodic_Report.xlsx,
Part_63_Subpart_H_63.182(e)_Fenceline_Quarterly_Report.xlsx,
Part_63_Subpart_U_63.506(e)(6)_Periodic_Report.xlsx, and
Part_63_Subpart_W_63.528(a)_Periodic_Report.xlsx, available in the
docket for this action.
---------------------------------------------------------------------------
Additionally, the EPA has identified two broad circumstances in
which electronic reporting extensions may be provided. These
circumstances are: (1) Outages of the EPA's CDX or CEDRI which preclude
an owner or operator from accessing the system and submitting required
reports and (2) force majeure events, which are defined as events that
will be or have been caused by circumstances beyond the control of the
affected facility, its contractors, or any entity controlled by the
affected facility that prevent an owner or operator from complying with
the requirement to submit a report electronically. Examples of force
majeure events are acts of nature, acts of war or terrorism, or
equipment failure or safety hazards beyond the control of the facility.
The EPA is providing these potential extensions in NSPS subparts VVb,
IIIa, NNNa, and RRRa (see proposed 40 CFR 60.487b (h) and (i), 40 CFR
60.615a (j) and (k), 40 CFR 60.665a(l) and (m), and 40 CFR 60.705(m)
and (n), respectively) to protect owners and operators from
noncompliance in cases where they cannot successfully submit a report
by the reporting deadline for reasons outside of their control. In both
circumstances, the decision to accept the claim of needing additional
time to report is within the discretion of the Administrator, and
reporting should occur as soon as possible. These potential extensions
are not necessary to add to the HON, P&R I, and P&R II because they
were recently added to 40 CFR part 63, subpart A, General Provisions at
40 CFR 63.9(k).
The electronic submittal of the reports addressed in these proposed
rulemakings will increase the usefulness of the data contained in those
reports, is in keeping with current trends in data availability and
transparency, will further assist in the protection of public health
and the environment, will improve compliance by facilitating the
ability of regulated facilities to demonstrate compliance with
requirements and by facilitating the ability of delegated state, local,
tribal, and territorial air agencies and the EPA to assess and
determine compliance, and will ultimately reduce burden on regulated
facilities, delegated air agencies, and the EPA. Electronic reporting
also eliminates paper-based, manual processes, thereby saving time and
resources, simplifying data entry, eliminating redundancies, minimizing
data reporting errors, and providing data quickly and accurately to the
affected facilities, air agencies, the EPA, and the public. Moreover,
electronic reporting is consistent with the EPA's plan \159\ to
implement Executive Order 13563 and is in keeping with the EPA's
Agency-wide policy \160\ developed in response to the White House's
Digital Government Strategy.\161\ For more information on the benefits
of electronic reporting, see the document titled Electronic Reporting
Requirements for New Source Performance Standards (NSPS) and National
Emission Standards for Hazardous Air Pollutants (NESHAP) Rules,
referenced earlier in this section.
---------------------------------------------------------------------------
\159\ EPA's Final Plan for Periodic Retrospective Reviews,
August 2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
\160\ E-Reporting Policy Statement for EPA Regulations,
September 2013. Available at: https://www.epa.gov/sites/production/files/2016-03/documents/epa-ereporting-policy-statement-2013-09-30.pdf.
\161\ Digital Government: Building a 21st Century Platform to
Better Serve the American People, May 2012. Available at: https://obamawhitehouse.archives.gov/sites/default/files/omb/egov/digital-government/digital-government.html.
---------------------------------------------------------------------------
4. NSPS Subpart VVa Reconsideration Issues
In January 2008, the EPA received one petition for reconsideration
of the NSPS subpart VVa rulemaking pursuant to CAA section 307(d)(7)(B)
from the following petitioners: American Chemistry Council, American
Petroleum Institute, and National Petrochemical and Refiners
Association (now the American Fuel and Petrochemical Manufacturers).
See section II.A.3 of this preamble for additional details about this
petition for reconsideration. On June 2, 2008, the EPA indicated (73 FR
31372) that it would be publishing a Federal Register notice in
response to the petition for reconsideration on: (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 at 40 CFR 60.481a and 40 CFR 60.482-
1a(g); (3) the monitoring of connectors in subpart VVa at 40 CFR
60.482-11a; and (4) the definition of capital expenditure in subpart
VVa at 40 CFR 60.481a. These provisions were stayed pending resolution
of the reconsideration.\162\ This action does not respond to the
reconsideration of NSPS subparts GGG and GGGa, as the EPA is not
reviewing those subparts in this action and instead is only proposing
to address issues 1 through 4 for subparts VV and VVa.
---------------------------------------------------------------------------
\162\ The EPA only granted reconsideration of issues 2 through 4
in their March 4, 2008 letter to petitioners, however, we are
proposing reconsideration on issue 1 (the clarification of the
definition of process unit) as well because of its reliance on issue
2 (the assignment of shared storage vessels to specific process
units).
---------------------------------------------------------------------------
On November 16, 2007, the EPA promulgated amendments to the NSPS
subpart VV as well as new equipment leak requirements in NSPS subpart
VVa.
[[Page 25172]]
As part of the rulemaking, the EPA finalized a definition for ``process
unit'' that included a phrase that a process unit ``includes all
equipment as defined in this subpart'' which was intended to clarify
what equipment was covered by the rule. However, petitioners stated
that the ``EPA must reconsider its `clarification' of the definition of
process unit'' because ``the new process unit definition is
inconsistent with the originally promulgated definition.'' The
petitioners alleged that the new definition ``substantially expands''
the definition of process unit, thereby expanding applicability of the
NSPS ``to equipment not previously subject to those requirements.''
They also state that because the EPA characterized this change as a
``clarification,'' we failed to solicit and consider public comments on
the impacts of this requirement for both existing and new SOCMI
facilities. After further review, the November 16, 2007, definition is
imprecise with respect to the usage of the terms ``equipment'' versus
``components.'' Equipment is a separately defined term and should not
be included within the definition of process unit to establish
applicability. The reader instead should be able to refer to 40 CFR
60.480(a) (for NSPS subpart VV) and 40 CFR 60.480a(a) (for NSPS subpart
VVa) for applicability and designation of the affected facility and
refer to 40 CFR 60.481 (for NSPS subpart VV) and 40 CFR 60.481a (for
NSPS subpart VVa) for definitions of terms used within the
applicability section. Therefore, we are proposing to revert back to
the same definition for ``process unit'' that is currently being used
in NSPS subpart VV and NSPS subpart VVa according to the stay
requirements. For NSPS subpart VV, we are proposing that ``process
unit'' means components assembled to produce, as intermediate or final
products, one or more of the chemicals listed in 40 CFR 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. For NSPS subpart VVa, we are proposing that ``process
unit'' means components assembled to produce, as intermediate or final
products, one or more of the chemicals listed in 40 CFR 60.489a of this
part. A process unit can operate independently if supplied with
sufficient feed or raw materials and sufficient storage facilities for
the product. These proposed definitions for ``process unit'' for NSPS
subparts VV and VVa avoid accidentally retroactively expanding coverage
of NSPS subparts VV and VVa to previously uncovered facilities.
Also, as part of the November 16, 2007 rulemaking, the EPA
finalized procedures at 40 CFR 60.482-1(g) (for NSPS subpart VV) and 40
CFR 60.482-1a(g) (for NSPS subpart VVa) intended to clarify how to
assign storage vessels that are shared among multiple process units to
a specific process unit. The EPA also revised the process unit
definition at 40 CFR 60.481 (for NSPS subpart VV) and 40 CFR 60.481a
(for NSPS subpart VVa) because of its reliance upon the new provision
on the allocation of shared storage vessels. Petitioners stated that
the EPA did not propose its method for addressing shared storage
vessels in the proposed rules published November 7, 2006, giving no
opportunity for public comment. The petitioners alleged that the
allocation of shared storage vessels is a new requirement ``that cannot
lawfully be imposed, with or without notice and comment, on existing
sources.'' After further review, we are proposing that a method for
assigning shared storage vessels to specific process units is not
needed. Therefore, we are proposing 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). For sources subject to NSPS subparts VV and VVa, any
storage vessel that is located within the battery limits \163\ of a
process unit is already associated with that process unit; therefore,
allocation is not necessary. We are soliciting comment on this proposed
decision, specifically regarding situations when allocation would be
necessary.
---------------------------------------------------------------------------
\163\ Statements made in the 1981 proposal preamble (46 FR 1136,
January 5, 1981) provide our clear intent of the components included
in the definition of process unit. First, the EPA specifically
stated that ``[a] process unit includes intermediate storage or
surge tanks and all fluid transport equipment connecting the
reaction, separation and purification devices.'' 46 FR 1139. This
statement clarified that the definition includes components
indirectly but still integrally involved in ``producing'' the
chemical (i.e., not a reaction, separation or purification unit
operation). Second, EPA stated: ``All equipment within the battery
limits is included'' but that ``offsite fluid transport and storage
facilities are excluded.'' Id. These terms, ``within the battery
limits'' and ``offsite,'' are industry terms of art used throughout
the SOCMI and petroleum refining industry. ``Within the battery
limits'' refers to the boundary around the components assembled to
perform a specific process function or to produce a product, whereas
``offsite'' refers to locations outside the fence line of a
facility. By using these terms, the EPA was emphasizing that all
components are part of the ``process unit'' if contained within the
battery limit boundary, but are not part of the process unit if
located ``offsite.'' Id.
---------------------------------------------------------------------------
In the November 16, 2007, rulemaking, the EPA finalized new
connector monitoring requirements for SOCMI units. Petitioners stated
that the ``EPA must reconsider its new connector monitoring
requirements for SOCMI units, as the regulated community was denied
notice of and an opportunity to comment on this requirement.'' The
Petitioners stated that the ``EPA expanded the definition of connector
in the final rule without notice and an opportunity to comment.'' The
EPA agrees that it did not include these new requirements and this new
definition in its proposal published on November 7, 2006. Therefore, we
are proposing to remove the connector monitoring provisions from NSPS
subpart VVa at 40 CFR 60.482-11a in their entirety. Instead, we are
reproposing connector monitoring provisions in NSPS subpart VVb (see
section III.C.6.b of this preamble).
Lastly, in the November 16, 2007 rulemaking, the EPA finalized a
definition of ``capital expenditure'' in NSPS subpart VVa. Petitioners
stated that the ``EPA must reconsider its new definition of `capital
expenditure' in subpart VVa, which was never proposed and which
retroactively triggers `modification' status for facility changes
commenced since November 7, 2006.'' The petitioners' concern was
specifically limited to the retroactive application, and not
application after November 16, 2007, and they did not seek
reconsideration with respect to the change in the definition of capital
expenditure generally. Therefore, we are proposing 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 (as is currently
required in NSPS subpart VVa due to the stayed provisions).
Specifically, we are proposing that the value of ``X'' in the capital
expenditure definition in 40 CFR 60.481a be 1982 minus the year of
construction for owners or operators that start a new, reconstructed,
or modified affected source prior to November 16, 2007, because using
any more recent year than 1982 as ``X'' in the equation would require
owners and operators to determine former (historical) capital
expenditures in order to meet modification and reconstruction
requirements. This would not be practical given that a significant
amount of time has passed since the capital expenditure provisions were
stayed. However, we are proposing to update the definition of ``capital
expenditure'' in NSPS subpart VVb for evaluating changes that occur at
existing SOCMI facilities after April 25, 2023. We are proposing that
the value of ``X'' in the
[[Page 25173]]
capital expenditure definition in 40 CFR 60.481b be 2023 minus the year
of construction, where the date of original construction was after
January 6, 1982, but before January 1, 2023. Where the date of original
construction was on or after January 1, 2023, but on or before April
25, 2023, we are proposing the value of X be 1.
5. Technical and Editorial Changes
We are proposing several technical amendments and definition
revisions to improve the clarity and enforceability of certain
provisions in the HON, P&R I, and P&R II, and NSPS subpart VVa. These
additional proposed revisions and our rationale for the proposed
revisions are described in this section.
a. HON Definition Sections
In an effort to remove redundancy and improve consistency, we are
proposing to move all of 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 (i.e., 40 CFR 63.101). We are
proposing new text in 40 CFR 63.111 to point to 40 CFR 63.101, as
follows: ``All terms used in this subpart shall have the meaning given
them in the Act and in subpart F of this part.'' We are proposing new
text in 40 CFR 63.161 to point to 40 CFR 63.101, as follows: ``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.'' We are also proposing to revise certain
terms that have minor differences between their definition in these
subparts. See Table 30 for additional details. These proposed changes
will resolve inconsistencies that lead to interpretation issues between
each of these subparts. We are not proposing to combine the definitions
from NESHAP subpart I into the definitions section of NESHAP subpart F
because those definitions are specifically for negotiated non-SOCMI
processes.
Table 30--Proposed Definition Changes To Resolve Minor Differences Between NESHAP F, G, and H
----------------------------------------------------------------------------------------------------------------
Proposed revised
Current definition in NESHAP subpart Current definition in Current definition in definition in NESHAP
F NESHAP subpart G NESHAP subpart H subpart F
----------------------------------------------------------------------------------------------------------------
None................................. Closed-vent system Closed-vent system Closed-vent system
means a system that is means a system that is means a system that is
not open to the not open to the not open to the
atmosphere and is atmosphere and that is atmosphere and is
composed of piping, composed of hard- composed of piping,
ductwork, connections, piping, ductwork, ductwork, connections,
and, if necessary, connections and, if and, if necessary,
flow inducing devices necessary, flow- flow inducing devices
that transport gas or inducing devices that that transport gas or
vapor from an emission transport gas or vapor vapor from an emission
point to a control from a piece or pieces point to a control
device. of equipment to a device.
control device or back
into a process.
Control device means any combustion Control device means Control device means Control device means
device, recovery device, or any combustion device, any equipment used for any combustion device,
recapture device. Such equipment recovery device, or recovering, recovery device, or
includes, but is not limited to, recapture device. Such recapturing, or recapture device. Such
absorbers, carbon adsorbers, equipment includes, oxidizing organic equipment includes,
condensers, incinerators, flares, but is not limited to, hazardous air but is not limited to,
boilers, and process heaters. For absorbers, carbon pollutant vapors. Such absorbers, carbon
process vents (as defined in this adsorbers, condensers, equipment includes, adsorbers, condensers,
section), recapture devices are incinerators, flares, but is not limited to, incinerators, flares,
considered control devices but boilers, and process absorbers, carbon boilers, and process
recovery devices are not considered heaters. For process adsorbers, condensers, heaters. For process
control devices. For a steam vents, recapture flares, boilers, and vents, recapture
stripper, a primary condenser is not devices are considered process heaters. devices are considered
considered a control device. control devices but control devices but
recovery devices are recovery devices are
not considered control not considered control
devices, and for a devices, and for a
steam stripper, a steam stripper, a
primary condenser is primary condenser is
not considered a not considered a
control device. control device.
None................................. First attempt at repair First attempt at repair First attempt at repair
means to take action means to take action means to take action
for the purpose of for the purpose of for the purpose of
stopping or reducing stopping or reducing stopping or reducing
leakage of organic leakage of organic leakage of organic
material to the material to the material to the
atmosphere. atmosphere, followed atmosphere, followed
by monitoring as by monitoring as
specified in Sec. specified in Sec.
63.180 (b) and (c), as 63.180 (b) and (c), as
appropriate, to verify appropriate, to verify
whether the leak is whether the leak is
repaired, unless the repaired, unless the
owner or operator owner or operator
determines by other determines by other
means that the leak is means that the leak is
not repaired. not repaired.
Initial start-up means the first time None................... Initial start-up means Initial start-up means
a new or reconstructed source begins the first time a new the first time a new
production, or, for equipment added or reconstructed or reconstructed
or changed as described in Sec. source begins source begins
63.100 (l) or (m) of this subpart, production. Initial production, or, for
the first time the equipment is put start-up does not equipment added or
into operation. Initial start-up include operation changed as described
does not include operation solely solely for testing in Sec. 63.100 (l)
for testing equipment. For purposes equipment. Initial or (m) of this
of subpart G of this part, initial start-up does not subpart, the first
start-up does not include subsequent include subsequent time the equipment is
start-ups (as defined in this start-ups (as defined put into operation.
section) of chemical manufacturing in this section) of Initial start-up does
process units following malfunctions process units not include operation
or shutdowns or following changes in following malfunctions solely for testing
product for flexible operation units or process unit equipment. For
or following recharging of equipment shutdowns. purposes of subpart G
in batch operation. For purposes of of this part, initial
subpart H of this part, initial start-up does not
start-up does not include subsequent include subsequent
start-ups (as defined in Sec. start-ups (as defined
63.161 of subpart H of this part) of in this section) of
process units (as defined in Sec. chemical manufacturing
63.161 of subpart H of this part) process units
following malfunctions or process following malfunctions
unit shutdowns. 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 Sec. 63.161 of
subpart H of this
part) of process units
(as defined in Sec.
63.161 of subpart H of
this part) following
malfunctions or
process unit
shutdowns.
[[Page 25174]]
None................................. Process unit has the Process unit means a Process unit means a
same meaning as chemical manufacturing chemical manufacturing
chemical manufacturing process unit as process unit as
process unit as defined in subpart F defined in subpart F
defined in this of this part, a of this part, a
section. process subject to the process subject to the
provisions of subpart provisions of subpart
I of this part, or a I of this part, or a
process subject to process subject to
another subpart in 40 another subpart in 40
CFR part 63 that CFR part 63 that
references this references this
subpart. subpart.
Surge control vessel means feed Surge control vessel Surge control vessel Surge control vessel
drums, recycle drums, and means feed drums, means feed drums, means feed drums,
intermediate vessels. Surge control recycle drums, and recycle drums, and recycle drums, and
vessels are used within a chemical intermediate vessels. intermediate vessels. intermediate vessels.
manufacturing process unit when in- Surge control vessels Surge control vessels Surge control vessels
process storage, mixing, or are used within a are used within a are used within a
management of flow rates or volumes chemical manufacturing process unit (as chemical manufacturing
is needed to assist in production of process unit when in- defined in the process unit when in-
a product. process storage, specific subpart that process storage,
mixing, or management references this mixing, or management
of flow rates or subpart) when in- of flow rates or
volumes is needed to process storage, volumes is needed to
assist in production mixing, or management assist in production
of a product. of flow rates or of a product.
volumes is needed to
assist in production
of a product.
----------------------------------------------------------------------------------------------------------------
Finally, we are also proposing editorial changes that clarify
reference citations in the definitions (to properly point to the
correct HON subpart) for ``annual average concentration,'' ``annual
average flow rate,'' ``closed biological treatment process,''
``compliance date,'' ``connector,'' ``continuous record,'' ``equipment
leak,'' ``group 1 process vent,'' ``group 1 storage vessel,'' ``group 1
wastewater stream,'' ``group 2 process vent,'' ``halogenated vent
stream,'' ``in organic hazardous air pollutant service,'' ``in volatile
organic compound service,'' ``instrumentation system,'' ``point of
determination,'' ``process vent,'' ``process wastewater stream,''
``recovery device,'' ``reference control technology for storage
vessels,'' ``reference control technology for wastewater,''
``repaired,'' ``table 8 compound,'' ``table 9 compound,'' ``total
resource effectiveness index value,'' ``treatment process,''
``wastewater,'' and ``wastewater stream''.
b. Monitoring for Adsorbers That Cannot Be Regenerated and Regenerative
Adsorbers That Are Regenerated Offsite
We are proposing to add 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 P&R I) for adsorbers that cannot be
regenerated and regenerative adsorbers that are regenerated offsite
because the HON and P&R I do not currently include specific monitoring
requirements for this type of APCD.\164\ We are proposing owners and
operators of this type of APCD use dual adsorbent beds in series. We
have prescribed a dual bed system because the use of a single bed does
not ensure continuous compliance unless the bed is replaced
significantly before breakthrough.\165\ The proposed monitoring
requirements for non-regenerative adsorbers fulfill the EPA's
obligation to establish monitoring requirements to ensure continuous
compliance with the emission limits (e.g., 98-percent control or a 20
ppm TOC outlet concentration) when owners or operators are using these
types of control devices to comply with the standards. A dual bed
system will allow one bed to be saturated before it is replaced and,
therefore, makes efficient use of the adsorber bed without exceeding
the emission limits.
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\164\ We did not find any P&R II facilities that have processes
controlled by adsorbers.
\165\ We are proposing to define the term ``breakthrough'' at 40
CFR 63.101 (for HON) and 40 CFR 63.482 (for P&R I) to mean the time
when the level of HAP or TOC detected is at the highest
concentration allowed to be discharged from an adsorber system.
---------------------------------------------------------------------------
Similar to regenerative adsorbers, in order to monitor performance
deterioration, we are proposing measurements of HAP or TOC using a
portable analyzer or chromatographic analysis for non-regenerative
absorbers. We are proposing that these measurements be taken on the
outlet of the first adsorber bed in series using a sample port; and
they be taken monthly (if the bed has at least two months of the bed
design life remaining), weekly (if the bed has between two months and
two weeks of bed design life remaining), or daily (once the bed has
less than two weeks of bed design life remaining). Also, owners and
operators would be required to establish an average adsorber bed life
from a design evaluation as well as conduct monitoring no later than 3
days after a bed is put into service as the first bed to confirm that
it is functioning properly.
We used the EPA's cost algorithms to estimate the cost of a second
carbon adsorber bed for two adsorber scenarios. In the first scenario,
the EPA estimated the cost of a replaceable-canister type adsorber
holding 180 lbs of carbon. The total capital investment of the second
bed (including installation and auxiliary equipment) is about $6,000,
and the total annual cost is about $800. In the second scenario, we
estimated the cost of an adsorber that holds 3,000 lbs of carbon and in
which the carbon is removed and replaced by fresh carbon when needed.
The total capital investment of the second bed (including installation
and auxiliary equipment) is about $26,600, and the total annual cost is
about $2,250. We assumed no additional labor would be required for
operation and maintenance of the second adsorber bed compared to
operating and maintaining a single bed adsorber. A more thorough
discussion of this analysis is included in the document titled Analysis
of Monitoring Costs and Dual Bed Costs for Non-Regenerative Carbon
Adsorbers Used in the SOCMI Source Category that are Associated with
Processes Subject to HON and for Non-Regenerative Carbon Adsorbers that
are Associated with Processes Subject to Group I Polymers and Resins
NESHAP, which is available in the docket for this rulemaking.
We anticipate that the use of two beds in series and the use of
monitoring will maximize the life of each bed and reduce adsorber media
replacement costs. In both scenarios described above, we assumed that
the first bed would be replaced when it reached breakthrough (i.e., its
equilibrium capacity, which is when the adsorption zone of the bed
reaches the bed outlet and the volatile
[[Page 25175]]
concentration in the exhaust begins to rise) based on monitoring at the
outlet of the first bed. At that time, the owner or operator would
divert the flow from the first to the second bed, the canisters or
carbon would be replaced in the first bed, and it would then be
returned to service as the second bed in the series. We did not include
the cost of replacing the canisters or the carbon in the annual costs
because the amount of carbon used would not increase as a result of
using a second bed in series. We anticipate that having two beds in
series and performing monitoring at the outlet of the first bed will
reduce the amount of adsorber media (e.g., activated carbon) used by
facilities because they will not have to replace the adsorber media
until it reaches equilibrium capacity. With only a single bed and no
monitoring, facilities would need to replace the adsorber media more
frequently based on the estimated working capacity of the bed (which is
a fraction of the equilibrium capacity) so as to maintain compliance
and to avoid exceeding outlet concentration limits.
As previously mentioned in section III.C.3.b of this preamble, we
are also proposing these same monitoring requirements for NSPS subpart
IIIa, NNNa, and RRRa under CAA section 111(b)(1)(B). The EPA
acknowledges that these proposed requirements could be considered under
CAA section 112(d)(6) because of the specification to have two adsorber
beds in series, instead of as a proposed change to the monitoring
requirements. However, our rationale for why a second bed is needed
would not be any different if we described these proposed changes under
CAA section 112(d)(6) instead of as a monitoring change. These changes
are being proposed because the current HON and P&R I contain no
monitoring requirements for non-regenerative adsorbers.
c. Calibration Drift Assessment (Related to NSPS Subpart VVa)
We are proposing several corrections to the calibration drift
assessment requirements in NSPS subpart VVa at 40 CFR 60.485a(b)(2).
These amendments are being proposed to: (1) Correct a regulatory
citation to read ``Sec. 60.486a(e)(8)'' instead of ``Sec.
60.486a(e)(7)''; (2) remove 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)
provide 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) provide 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 note that we are proposing
these same calibration drift assessment requirements in NSPS subpart
VVb at 40 CFR 60.485b(b)(2).
d. Control of Sweep, Purge, and Inert Blankets From IFRs
The EPA is proposing 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 (see proposed 40 CFR 63.119(b)(7)).
e. Overlap Provisions
The EPA is proposing to 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 proposed 40 CFR 63.110(h)) because
revisions being proposed in the HON are and not reflective of the same
standards and associated monitoring, recordkeeping, and reporting
requirements for certain control devices such as flares. In addition,
requiring all facilities to have the same set of monitoring,
recordkeeping, and reporting requirements allows for better
enforceability of the rule by the EPA.
Also, the EPA is proposing to 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 proposed 40 CFR 63.110(i) and 40 CFR
60.160(g)) because our proposed requirements for HON processes (i.e.,
requirements we are proposing for heat exchange systems, storage
vessels, process vents, transfer racks, wastewater, and equipment
leaks) are more stringent than those required by 40 CFR part 65.
f. Other Editorial Corrections
The EPA is proposing additional changes that address technical and
editorial corrections for the HON as follows:
The EPA is proposing to remove the word ``Organic'' before
Hazardous Air Pollutants from the 40 CFR part 63 titles of subparts F
through I to reflect the acronym NESHAP more accurately and for
consistency in naming convention across all 40 CFR part 63 subparts;
and
The EPA is proposing to add the phrase ``and Fenceline
Monitoring for All Emission Sources'' to the title of NESHAP subpart H
to reflect the contents of the NESHAP more accurately. The EPA is
proposing to include fenceline monitoring standards in NESHAP subpart H
(see section III.C.7 of this preamble).
6. Listing of 1-bromopropane as a HAP
On January 5, 2022, the EPA published in the Federal Register (87
FR 393) a final rule amending the list of HAP under the CAA to add 1-
bromopropane (1-BP) in response to public petitions previously granted
by the EPA. For the source categories covered by the HON, P&R I, and
P&R II, we do not believe that the inclusion of 1-BP as an organic HAP
would have any effect on the MACT standards. First, 1-BP is not a SOCMI
chemical. Furthermore, we have no information showing that 1-BP is
used, produced, or emitted to make any SOCMI chemicals regulated by the
HON, and we are unaware of any information showing that it is used,
produced, or emitted in the production of any of the polymers and
resins processes covered by the P&R I or P&R II. Accordingly, we
believe there is no further action required by the EPA needed to
address emissions of 1-BP from these source categories. We solicit
comment on this approach, and should new information submitted to the
EPA show that 1-BP is emitted from these source categories, the EPA
will consider this information in the context of developing any MACT
standards that may be needed to address emissions of 1-BP. We also note
that in many instances in the HON and P&R I, many MACT emission
standards allow facilities to comply with a total organic compound
concentration standard (e.g., 20 ppmv), which could adequately regulate
emissions of 1-BP should we receive additional information that it is
emitted from these source categories.
F. What compliance dates are we proposing, and what is the rationale
for the proposed compliance dates?
1. HON, P&R I, and P&R II
The proposed amendments to the HON, P&R I, and P&R II in this
rulemaking for adoption under CAA section 112(d)(2) and (3) (see
section III.D of this preamble) and CAA section 112(d)(6) (see section
III.C of this preamble) are subject to the compliance deadlines
outlined in the CAA under section 112(i). The proposed amendments to
the HON and P&R I in
[[Page 25176]]
this rulemaking for adoption under CAA section 112(f) (see section
III.C of this preamble) are subject to the compliance deadlines
outlined in the CAA under section 112(f)(4).
For all of the requirements we are proposing under CAA sections
112(d)(2), (3), and (d)(6), we are proposing that all existing affected
sources and all affected sources that were new sources under the
current HON and P&R I (i.e., they commenced construction or
reconstruction after December 31, 1992 (for HON) or after June 12, 1995
(for P&R I), and on or before April 25, 2023), must comply with all of
the amendments no later than 3 years after the effective date of the
final rule, or upon startup, whichever is later. For existing sources,
CAA section 112(i) provides that the compliance date shall be as
expeditious as practicable, but no later than 3 years after the
effective date of the standard. (``Section 112(i)(3)'s three-year
maximum compliance period applies generally to any emission standard .
. . promulgated under [section 112].'' Association of Battery Recyclers
v. EPA, 716 F.3d 667, 672 (D.C. Cir. 2013)). In determining what
compliance period is as expeditious as practicable, we consider the
amount of time needed to plan and construct projects and change
operating procedures. 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 would be required to comply with
these requirements within 60 days after the publication of the final
amendments to the HON, P&R I, and P&R II standards or upon startup,
whichever is later.
For all of the requirements we are proposing under CAA sections
112(f), we are proposing a compliance date of 2 years after the
effective date of the final rule, or upon startup, whichever is later
for all existing affected sources and for all affected sources that
were new sources under the current HON and P&R I (i.e., they commenced
construction or reconstruction after December 31, 1992 (for HON) or
after June 12, 1995 (for P&R I), and on or before April 25, 2023, to
comply with the proposed EtO requirements (for HON) and the proposed
chloroprene requirements (for P&R I affected sources producing
neoprene). For all new affected sources that commence construction or
reconstruction after April 25, 2023, we are proposing owners or
operators comply with the EtO requirements (for HON) and the
chloroprene requirements (for P&R I affected sources producing
neoprene) within 60 days after the publication date of the final rule
(or upon startup, whichever is later).
a. Rationale for Proposed Compliance Dates of Proposed CAA Section
112(d)(2) and (3) Amendments
We are proposing new operating and monitoring requirements for the
HON and P&R I under CAA section 112(d)(2) and (3). We anticipate that
these requirements would require the installation of new flare
monitoring equipment, and we project most CMPUs and EPPUs would install
new control systems to monitor and adjust assist gas (air or steam)
addition rates. Similar to the addition of new control equipment, these
new monitoring requirements for flares would require engineering
evaluations, solicitation and review of vendor quotes, contracting and
installation of the equipment, and operator training. Installation of
new monitoring and control equipment on flares will require the flare
to be taken out of service. Depending on the configuration of the
flares and flare header system, taking the flare out of service may
also require a significant portion of the CMPU or EPPU to be shutdown.
Therefore, for all existing affected sources, and all new affected
sources under the current HON and P&R I that commenced construction or
reconstruction after December 31, 1992 (for HON) or after June 12, 1995
(for P&R I), and on or before April 25, 2023, we are proposing that it
is necessary to provide 3 years after the publication date of the final
rule (or upon startup, whichever is later) for owners or operators to
comply with the new operating and monitoring requirements for flares.
For all new affected sources that commence construction or
reconstruction after April 25, 2023, we are proposing owners or
operators comply with the new operating and monitoring requirements for
flares within 60 days after the publication date of the final rule (or
upon startup, whichever is later).
Under CAA section 112(d)(2) and (3), we are proposing new vent
control requirements for bypasses for the HON and P&R I. These
requirements would typically require the addition of piping and
potentially new control requirements. As these vent controls would most
likely be routed to the flare, we are proposing, for all existing
affected sources, and all new affected sources under the current HON
and P&R I that commenced construction or reconstruction after December
31, 1992 (for HON) or after June 12, 1995 (for P&R I), and on or before
April 25, 2023, to provide 3 years after the publication date of the
final rule (or upon startup, whichever is later) for owners or
operators to allow coordination of these bypass modifications with the
installation of the new monitoring equipment for the flares. For all
new affected sources that commence construction or reconstruction after
April 25, 2023, we are proposing owners or operators comply with the
new vent control requirements for bypasses within 60 days after the
publication date of the final rule (or upon startup, whichever is
later).
For atmospheric PRD in HAP service, we are establishing a work
practice standard in the HON and P&R I that requires a process hazard
analysis and implementation of a minimum of three redundant measures to
prevent atmospheric releases. Alternately, owners or operators may
elect to install closed-vent systems to route these PRDs to a flare,
drain (for liquid thermal relief valves), or other control system. We
anticipate that sources will need to identify the most appropriate
preventive measures or control approach; design, install, and test the
system; install necessary process instrumentation and safety systems;
and may need to time installations with equipment shutdown or
maintenance outages. Therefore, for all existing affected sources, and
all new affected sources under the current HON and P&R I that commenced
construction or reconstruction after December 31, 1992 (for HON) or
after June 12, 1995 (for P&R I), and on or before April 25, 2023, we
are proposing a compliance date of 3 years from the publication date of
the final rule (or upon startup, whichever is later) for owners or
operators to comply with the work practice standards for atmospheric
PRD releases. For all new affected sources that commence construction
or reconstruction after April 25, 2023, we are proposing owners or
operators comply with the work practice standards for atmospheric PRD
releases within 60 days after the publication date of the final rule
(or upon startup, whichever is later).
We are also establishing work practice standards in the HON and P&R
I for maintenance activities. We anticipate sources will need time to
review and update their standard operating procedures for maintenance
activities; identify the most appropriate preventive measures or
control approaches; design, install, and test the control systems; and
install necessary process instrumentation and safety systems if so
required. Therefore, for all existing affected sources, and all new
affected sources under the current HON and P&R I that commenced
construction or reconstruction after December 31, 1992
[[Page 25177]]
(for HON) or after June 12, 1995 (for P&R I), and on or before April
25, 2023, we are proposing a compliance date of 3 years from the
publication date of the final rule (or upon startup, whichever is
later) for owners or operators to comply with the work practice
standards for maintenance activities. For all new affected sources that
commence construction or reconstruction after April 25, 2023, we are
proposing owners or operators comply with the work practice standards
for maintenance activities within 60 days after the publication date of
the final rule (or upon startup, whichever is later).
Under CAA section 112(d)(2) and (3), we are also proposing new
dioxins and furans emission limits for the HON, P&R I, and P&R II. The
proposed provisions may require additional time to plan, purchase, and
install equipment for dioxins and furans control. Therefore, for all
existing affected sources, and all new affected sources under the
current HON, P&R I, and P&R II that commenced construction or
reconstruction after December 31, 1992 (for HON), or after May 16, 1994
(for P&R II), or after June 12, 1995 (for P&R I), and on or before
April 25, 2023, we are proposing a compliance date of 3 years from the
publication date of the final rule (or upon startup, whichever is
later) for owners or operators to comply with the dioxins and furans
emission limits. For all new affected sources that commence
construction or reconstruction after April 25, 2023, we are proposing
owners or operators comply with the dioxins and furans emission limits
within 60 days after the publication date of the final rule (or upon
startup, whichever is later).
Other amendments we are proposing under CAA section 112(d)(2) and
(3) include LDAR requirements for HON and P&R I pressure vessels,
process vent control requirements for certain HON and P&R I surge
control vessels and bottoms receivers, control requirements for certain
HON transfer racks with an operating pressure greater than 204.9 kPa,
and a LDAR program for P&R II heat exchange systems for BLR and WSR
sources and equipment leaks for WSR sources in P&R II. Any of these
proposed provisions may require additional time to plan, purchase, and
install equipment for emissions control; and even if not, the EPA
recognizes the confusion that multiple different compliance dates for
individual requirements would create and the additional burden such an
assortment of dates would impose. Therefore, for all existing affected
sources, and all new affected sources under the current rules that
commenced construction or reconstruction after December 31, 1992 (for
HON), or after May 16, 1994 (for P&R II), or after June 12, 1995 (for
P&R I), and on or before April 25, 2023, we are proposing a compliance
date of 3 years from the publication date of the final rule (or upon
startup, whichever is later) for owners or operators to comply with
these other proposed amendments. For all new affected sources that
commence construction or reconstruction after April 25, 2023, we are
proposing owners or operators comply with these other proposed
amendments within 60 days after the publication date of the final rule
(or upon startup, whichever is later).
b. Rationale for Proposed Compliance Dates of Proposed CAA Section
112(d)(6) Amendments
As a result of our technology review for HON and P&R I heat
exchange systems, we are proposing to replace the existing HON and P&R
I leak definition and monitoring method with a new leak definition and
monitoring method. We project some owners and operators would require
engineering evaluations, solicitation and review of vendor quotes,
contracting and installation of monitoring equipment, and operator
training. In addition, facilities will need time to read and understand
the amended rule requirements and update standard operating procedures.
Therefore, we are proposing that all existing affected sources, and all
new affected sources under the current rules that commenced
construction or reconstruction after December 31, 1992 (for HON) or
after June 12, 1995 (for P&R I), and on or before April 25, 2023, must
comply with the new monitoring requirements for heat exchange systems
no later than 3 years from the publication date of the final rule (or
upon startup, whichever is later). For all new affected sources that
commence construction or reconstruction after April 25, 2023, we are
proposing owners or operators comply with the new monitoring
requirements for heat exchange systems within 60 days after the
publication date of the final rule (or upon startup, whichever is
later).
Under our technology review for HON and P&R I storage vessels under
CAA section 112(d)(6), we are revising HON and P&R I to reflect more
stringent storage vessel capacity and MTVP thresholds. We project that
some owners and operators will need to install new control equipment on
certain storage vessels because of the proposed applicability
revisions. The addition of new control equipment would require
engineering design, solicitation, and review of vendor quotes, and
contracting and installation of the equipment, which would need to be
timed with process unit outage and operator training. Therefore, we are
proposing that all existing affected sources, and all new affected
sources under the current rules that commenced construction or
reconstruction after December 31, 1992 (for HON) or after June 12, 1995
(for P&R I), and on or before April 25, 2023, must comply with the new
storage vessel requirements no later than 3 years from the publication
date of the final rule (or upon startup, whichever is later). For all
new affected sources that commence construction or reconstruction after
April 25, 2023, we are proposing owners or operators comply with the
new storage vessel requirements within 60 days after the publication
date of the final rule (or upon startup, whichever is later).
We are also proposing, pursuant to CAA section 112(d)(6), to remove
the 50 ppmv and 0.005 scmm Group 1 process vent thresholds from the HON
Group 1 process vent definition and P&R I Group 1 continuous front-end
process vent definition, and instead require owners and operators of
HON or P&R I process vents that emit greater than or equal to 1.0 lb/hr
of total organic HAP 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, whichever is less stringent.
Additionally, as a result of our technology review for P&R I batch
front-end process vents, we are proposing owners and operators of batch
front-end process vents that release a total of 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 would be required to reduce
emissions of organic HAP from these process vents using a flare meeting
the proposed operating and monitoring requirements for flares; or
reduce emissions of organic HAP or 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). We project that some owners and
operators will need to install new control equipment and/or new hard-
piping or duct work for certain process vents because of the proposed
applicability revisions. The addition of new control equipment would
require engineering design, solicitation, and review of vendor quotes,
and contracting and installation of the equipment, which would need to
be timed with process unit outage and
[[Page 25178]]
operator training. Therefore, we are proposing that all existing
affected sources, and all new affected sources under the current rules
that commenced construction or reconstruction after December 31, 1992
(for HON) or after June 12, 1995 (for P&R I), and on or before April
25, 2023, must comply with the new process vent requirements no later
than 3 years from the publication date of the final rule (or upon
startup, whichever is later). For all new affected sources that
commence construction or reconstruction after April 25, 2023, we are
proposing owners or operators comply with the new process vent
requirements within 60 days after the publication date of the final
rule (or upon startup, whichever is later).
Compliance dates for the fenceline monitoring provisions proposed
under CAA section 112 (d)(6) consider the amount of time that it will
take owners and operators to develop their siting plans and secure the
capabilities to conduct the monitoring and analyze the results. For
fenceline monitoring, the compliance timeline also must consider the
timeline for controls to be installed and operational before root cause
analysis and application of corrective measures can take place.
However, the actual monitoring can and must begin at least a year
before to develop the annual average concentration baseline. Therefore,
we are proposing that owners and operators of all existing sources and
all new affected sources under the current rules that commenced
construction or reconstruction after December 31, 1992 (for HON) or
after June 12, 1995 (for P&R I), and on or before April 25, 2023 must
begin fenceline monitoring one year after the publication date of the
final rule and must perform root cause analysis and apply corrective
action requirements upon exceedance of an annual average concentration
action level starting 3 years after the publication date of the final
rule (i.e., such that by after two years after the publication date of
this rule, facilities will have installed controls to reduce EtO and
chloroprene (as discussed in section III.F.1.c of this preamble) and be
able to compare 1 year of data to the annual average concentration
action level by year 3). For all new affected sources that commence
construction or reconstruction after April 25, 2023, we are proposing
owners or operators begin fenceline monitoring within 60 days after the
publication date of the final rule (or upon startup, whichever is
later). We are also proposing to require quarterly reporting of
fenceline results beginning 1 year after monitoring begins.
c. Rationale for Proposed Compliance Dates of Proposed CAA Section
112(f) Amendments
As previously mentioned in this preamble, we are proposing under
CAA section 112(f), new provisions considering results of the risk
assessments to address emissions of EtO from equipment leaks, flares,
heat exchange systems, maintenance vents, process vents, storage
vessels, and wastewater at HON processes; and emissions of chloroprene
from continuous front-end process vents, batch front-end process vents,
maintenance vents, storage vessels, and wastewater associated with
neoprene production processes subject to P&R I. The proposed provisions
will require additional time to plan, purchase, and install equipment
for EtO or chloroprene control. For example, for HON process vents in
EtO service, if the 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 will need to be installed. Therefore,
we are proposing a compliance date of 2 years after the publication
date of the final rule, or upon startup, whichever is later for all
existing affected sources, and all new affected sources under the
current rules that commenced construction or reconstruction after
December 31, 1992 (for HON) or after June 12, 1995 (for P&R I), and on
or before April 25, 2023 to comply with the proposed EtO and
chloroprene requirements. For all new affected sources that commence
construction or reconstruction after April 25, 2023, we are proposing
owners or operators comply with the EtO and chloroprene requirements
within 60 days after the publication date of the final rule (or upon
startup, whichever is later).
d. Rationale for Proposed Compliance Dates of Other Proposed Amendments
We are proposing to change the HON, P&R I, and P&R II requirements
for SSM by removing the exemption from the requirements to meet the
standard during SSM periods, proposing alternative standards where
needed, and by removing the requirement to develop and implement an SSM
plan. In addition, we are proposing to remove all of the regulatory
affirmative defense provisions from P&R I. We are also proposing
electronic reporting requirements for the HON, P&R I, and P&R II. For
details on these proposed amendments, see section III.E of this
preamble. Except for the removal of the affirmative defense provisions
in P&R I, we are positing that facilities would need some time to
successfully accomplish these revisions, including time to read and
understand the amended rule requirements, to evaluate their operations
to ensure that they can meet the standards during periods of startup
and shutdown, as defined in the rule, and make any necessary
adjustments, including making adjustments to standard operating
procedures, and to convert reporting mechanisms to install necessary
hardware and software. As previously mentioned, the EPA recognizes the
confusion that multiple different compliance dates for individual
requirements would create and the additional burden such an assortment
of dates would impose. From our assessment of the timeframe needed for
compliance with the entirety of the proposed revisions to SSM
requirements as well as the new proposed electronic reporting
requirements for flare management plans, compliance reports, and
performance evaluation reports, the EPA considers a period of 3 years
after the publication date of the final rule to be the most expeditious
compliance period practicable and, thus, is proposing that all affected
sources be in compliance with these revised requirements upon initial
startup or within 3 years of the publication date of the final rule,
whichever is later. However, we are proposing to provide 60 days after
the publication date of the final rule (or upon startup, whichever is
later) for owners or operators of all affected sources to comply with
the requirement to report electronically. We are also proposing to
provide 60 days after the publication date of the final rule (or upon
startup, whichever is later) for owners or operators of P&R I affected
sources to comply with the removal of the affirmative defense
provisions.
2. NSPS Subparts VVb, IIIa, NNNa, RRRa
We are proposing that all sources of equipment leaks in the SOCMI
(regulated under 40 CFR part 60, subpart VVb) and all SOCMI air
oxidation unit processes, distillation operations, and reactor
processes (regulated under 40 CFR part 60, subparts IIIa, NNNa, and
RRRa, respectively), that commenced construction, reconstruction, or
modification on or after April 25, 2023, would need to meet the
requirements of the new NSPS upon startup of the new, reconstructed or
modified facility or 60
[[Page 25179]]
days after publication of the final rule, whichever is later. This
proposed compliance schedule is consistent with the requirements in
section 111 of the CAA and the Congressional Review Act.
IV. Summary of Cost, Environmental, and Economic Impacts
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 three
years. The OECA's ECHO 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, which is available in the docket for this rulemaking. We
estimated that there would 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 estimated there would 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 would trigger NSPS subpart
VVa reconstruction requirements).
B. What are the air quality impacts?
This proposed action would reduce HAP and VOC emissions 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. Considering reported emissions inventories
for EtO and chloroprene, we estimate that the proposed amendments to
the NESHAP would reduce overall HAP emissions from the SOCMI source
category by approximately 1,009 tpy, reduce overall HAP emissions from
the P&R I source categories by approximately 185 tpy, and reduce
overall HAP 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 proposed monitoring requirements; we estimate
flare excess emissions reductions of 4,858 tpy HAP and 19,889 tpy VOC.
Based on our analysis of the proposed actions described in sections
III.C.3.b and III.C.6.b of this preamble for the NSPS, we estimate that
the proposed amendments to the NSPS would reduce VOC emissions from the
SOCMI source category by approximately 1,609 tpy. Emission reductions
and secondary impacts (e.g., emission increases associated with
supplemental fuel or additional electricity) by rule are listed below.
1. HON
For the HON, the EPA estimates HAP and VOC emission reductions of
approximately 1,009 and 1,817 tpy, respectively. The EPA estimates
these reductions include an approximate 58 tpy reduction in EtO
emissions (from reported emissions inventories). The EPA also estimates
that the proposed action would result in additional emissions of 714
tpy of carbon monoxide (CO), 609,761 tpy of carbon dioxide
(CO2), 277 tpy of nitrogen oxides (NOX)
(including 5.3 tpy of nitrous oxide (N2O)), 12.7 tpy of
particulate matter, 1.0 tpy of sulfur dioxide (SO2), and a
reduction of 20,177 tpy of methane emissions. More information about
the estimated emission reductions and secondary impacts of this
proposed action for the HON can be found in the RIA accompanying this
proposal and in the documents referenced in sections III.B through
III.D of this preamble.
2. P&R I
For P&R I, the EPA estimates HAP and VOC emission reductions of
approximately 185 and 199 tpy, respectively. The EPA estimates these
reductions include an approximate 14 tpy reduction in chloroprene
emissions (from reported emissions inventories). The EPA also estimates
that the proposed 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,
0.4 tpy of SO2, and a reduction of 2,018 tpy of methane
emissions. More information about the estimated emission reductions and
secondary impacts of this proposed action for P&R I can be found in the
RIA accompanying this proposal and in the documents referenced in
sections III.B through III.D of this preamble.
3. P&R II
For P&R II, the EPA estimates 1 tpy of HAP and VOC emission
reductions. The EPA also estimates that the proposed action would not
have any secondary pollutant impacts. More information about the
estimated emission reductions and secondary impacts of this proposed
action for P&R II can be found in the RIA accompanying this proposal
and in the documents referenced in sections III.B through III.D of this
preamble.
4. NSPS Subpart VVb
For the proposed NSPS subpart VVb, the EPA estimates VOC emission
reductions of approximately 340 tpy. The EPA estimates that the
proposed action would not have any secondary pollutant impacts. More
information about the estimated emission reductions and secondary
impacts of this proposed action for NSPS subpart VVb can be found in
the RIA accompanying this proposal and in the document titled CAA
111(b)(1)(B) review for the SOCMI Equipment Leaks NSPS Subpart VVa,
which is available in the docket for this rulemaking.
5. NSPS Subparts IIIa, NNNa, and RRRa
For the proposed NSPS subparts IIIa, NNNa, and RRRa, the EPA
estimates VOC emission reductions of approximately 1,269 tpy. The EPA
estimates that the proposed 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), and a reduction
of 757 tpy of methane emissions. More information about the estimated
emission reductions and secondary impacts of this proposed action for
NSPS subparts IIIa, NNNa, and RRRa can be found in the RIA accompanying
this proposal 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, which is available
in the docket for this rulemaking.
C. What are the cost impacts?
This proposed action would cumulatively cost (in 2021 dollars)
approximately $501 million in total capital costs and $190 million per
year in total annualized costs (including product recovery), based on
our analysis of the proposed action described in sections III.B through
III.D of this preamble. Costs by rule are listed below.
1. HON
For the HON, the EPA estimates this proposed action would cost
approximately $441 million in total capital costs and $166 million per
year in total annualized costs (including product recovery). More
information about the estimated cost of this
[[Page 25180]]
proposed action for the HON can be found in the documents referenced in
sections III.B through III.D of this preamble.
2. P&R I
For P&R I, the EPA estimates this proposed action would cost
approximately $25 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 proposed action for P&R I
can be found in the documents referenced in sections III.B through
III.D of this preamble.
3. P&R II
For P&R II, the EPA estimates this proposed action would 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 proposed action for P&R II
can be found in the documents referenced in sections III.B through
III.D of this preamble.
4. NSPS Subpart VVb
For the proposed NSPS subpart VVb, the EPA estimates this proposed
action would 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 proposed
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,
which is available in the docket for this rulemaking.
5. NSPS Subparts IIIa, NNNa, and RRRa
For the proposed NSPS subparts IIIa, NNNa, and RRRa, the EPA
estimates this proposed action would cost approximately $24 million in
total capital costs and $5.8 million per year in total annualized costs
(including product recovery). More information about the estimated cost
of this proposed 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, which is available in the
docket for this rulemaking.
D. What are the economic impacts?
The EPA conducted economic impact analyses for this proposal, in a
document titled Regulatory Impact Analysis, which is available in the
docket for this action. The economic impact analyses contain two parts.
The economic impacts of the proposal 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 VVb, IIIa, NNNa, and RRRa facilities
while presuming no impact on consumers. We estimate the average small
entity impacted by the proposal will incur total annualized costs of
0.46 percent of their revenue, with none exceeding 1.5 percent, not
considering product recovery from compliance. With product recovery,
the EPA estimates that the average small entity impacted by the
proposal will incur total annualized costs of 0.43 percent of their
revenue, with none exceeding 1.3 percent. We estimate that 20 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 a credit.
In addition, we provide an economic impact analysis using costs of
the HON and Polymers and Resins 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 proposed rules. There are seven chemical
products included in the economic impact analysis--butadiene, styrene,
acetone, acrylonitrile, ethylene dichloride, ethylene glycol, and
ethylene oxide. 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 Polymers and Resins 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 RIA for this proposed rulemaking.
E. What are the benefits?
The emissions controls required by these rules are expected to
reduce emissions of a number of HAP. 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:
ethylene oxide (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
proposal is projected to reduce ethylene oxide emissions from HON
processes by approximately 58 tons per year (tpy) and reduce
chloroprene emissions from Neoprene Production processes in P&R I by
approximately 14 tpy. We also estimate that the proposed amendments to
the NESHAP would reduce other HAP emissions (excluding ethylene oxide
and chloroprene) from the SOCMI, P&R I, and P&R II source categories by
approximately 1,123 tpy. We also estimate that the proposed 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 proposed
amendments to the NSPS in this rulemaking.
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 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 proposed action.
The emission controls installed to comply with these proposed 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
[[Page 25181]]
Assessment for Ozone (Ozone ISA) \166\ as summarized in the Technical
Support Document for the Final Revised Cross State Air Pollution Rule
Update.\167\ 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.
---------------------------------------------------------------------------
\166\ 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.
\167\ 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.
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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.
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. 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
(i.e., negative effects) from additional CO2 and
NOX emissions, which occur with the HON, P&R I and NSPS
IIIa, NNNa, and RRRa, but not P&R II or NSPS VVb since there are no
additional CO2 emissions as a result of these two proposed
rules.
1. HON
The present value (PV) of the net monetized benefits (monetized
health benefits plus monetized climate benefits minus climate
disbenefits) for the proposed amendments for the HON are $103.4 million
at the 3 percent discount rate to $78.4 million at the 7 percent
discount rate and $715.4 million at the 3 percent discount rate to
$495.4 million at the 7 percent discount rate. The equivalent annual
value (EAV) of the benefits for the proposed amendments for the HON are
$8.6 million at the 3 percent discount rate to $7.9 million at the 7
percent discount rate and $60.1 million at the 3 percent discount rate
to $53.1 million at the 7 percent discount rate.
2. P&R I
The PV of the net monetized benefits (monetized health benefits
plus monetized climate benefits minus monetized climate disbenefits)
for the proposed amendments for P&R I are minus $37.8 million at the 3
percent discount rate to minus $38.6 million at the 7 percent discount
rate and minus $17.5 million at the 3 percent discount rate to minus
$24.5 million at the 7 percent discount rate. The EAV of the benefits
for the proposed amendments for P&R I are minus $0.8 million at the 3
percent discount rate to minus $1.6 million at the 7 percent discount
rate and minus $1.5 million at the 3 percent discount rate to minus
$1.7 million at the 7 percent discount rate.
3. P&R II
The PV of the net monetized benefits (monetized health benefits
plus monetized climate benefits minus monetized climate disbenefits)
for the proposed amendments for P&R II 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
Because the estimated emissions reductions due to this proposed
rule are relatively small and because we cannot be confident of the
location of new facilities that would be subject to the proposed NSPS
subpart VVb, the EPA elected to use the benefit per-ton (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 proposed NSPS. Thus, all
monetized benefits are human health benefits from VOC reductions.
The PV of the net monetized benefits (monetized health benefits
only) for the proposed NSPS subpart VVb are $1.2 million at the 3
percent discount rate to $0.9 million at the 7 percent discount rate
and $11 million at the 3 percent discount rate to $7.5 million at the 7
percent discount rate. The EAV of the benefits for the proposed 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
Because the estimated emissions reductions due to this rule are
relatively small and because we cannot be confident of the location of
new facilities that would be subject to the proposed NSPS subparts
IIIa, NNNa, and RRRa, 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. 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 proposed NSPS.
The PV of the net monetized benefits (monetized health benefits
plus monetized climate benefits minus monetized climate disbenefits)
for the proposed NSPS subparts IIIa, NNNa, and RRRa are $11.4 million
at the 3 percent discount rate to $10.0 million at the 7 percent
discount rate and $47.8 million at the 3 percent discount rate to $34.8
million at the 7 percent discount rate. The EAV of the benefits for the
proposed NSPS subparts IIIa, NNNa, and RRRa are $1.0 million at the 3
percent discount rate to $0.9 million at the 7 percent discount rate
and $4.1 million at the 3 percent discount rate to $3.6 million at the
7 percent discount rate.
F. What analysis of environmental justice did we conduct?
Executive Order 12898 directs EPA to identify the populations of
concern who are most likely to experience unequal burdens from
environmental harms, which are specifically minority populations
(people of color), low-
[[Page 25182]]
income populations, and Indigenous peoples (59 FR 7629, February 16,
1994). Additionally, Executive Order 13985 is intended to advance
racial equity and support underserved communities through Federal
government actions (86 FR 7009, January 20, 2021). For this action,
pursuant to these Executive Orders, the EPA conducted an assessment of
the impacts that would result from the proposed rule amendments, if
promulgated, on communities with environmental justice (EJ) concerns.
However, this assessment did not inform the technical and scientific
determinations made to support the proposed rule amendments in this
action. The EPA defines EJ as ``the fair treatment and meaningful
involvement of all people regardless of race, color, national origin,
or income, with respect to the development, implementation, and
enforcement of environmental laws, regulations, and policies.'' \168\
The EPA further defines fair treatment to mean that ``no group of
people should bear a disproportionate burden of environmental harms and
risks, including those resulting from the negative environmental
consequences of industrial, governmental, and commercial operations or
programs and policies.'' In recognizing that people of color and low-
income populations often bear an unequal burden of environmental harms
and risks, the EPA continues to consider ways of protecting them from
adverse public health and environmental effects of air pollution. For
purposes of analyzing regulatory impacts, the EPA relies upon its June
2016 ``Technical Guidance for Assessing Environmental Justice in
Regulatory Analysis,'' \169\ 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 minority populations, low-income populations, and/or
Indigenous peoples; (2) exacerbate existing disproportionate impacts on
minority populations, low-income populations, and/or Indigenous
peoples; or (3) present opportunities to address existing
disproportionate impacts on minority populations, low-income
populations, and/or Indigenous peoples through this action under
development.
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\168\ https://www.epa.gov/environmentaljustice.
\169\ See https://www.epa.gov/environmentaljustice/technical-guidance-assessing-environmental-justice-regulatory-analysis.
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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
considered in this proposal. Specifically, the EPA analyzed how
demographics and risk are distributed both pre- and post-control,
enabling us to address the core questions that are posed in the EPA's
2016 Technical Guidance for Assessing Environmental Justice in
Regulatory Analysis. In conducting this analysis, we considered key
variables highlighted in the guidance including ``minority populations
(people of color and Hispanic or Latino), low-income populations, and/
or indigenous peoples.'' 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) Facilities, which is available in the docket for this
action.
To examine the potential for EJ concerns, the EPA conducted a
baseline proximity analysis, baseline risk-based analysis (i.e., before
implementation of any controls proposed by this action), and post-
control risk-based analysis (i.e., after implementation of the controls
proposed by this 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 proposed by this 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
proposed by this action (``post-control''). In this preamble, we focus
on the 10 km radius for the demographic analysis because it encompasses
all the facility 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 proximity 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) Facilities,
which is available in the docket for this action.
Under the risk-based demographic analysis, the total population,
population percentages, and population count for each demographic group
for the entire U.S. population is shown in the column titled
``Nationwide Average for Reference'' in Tables 31 through 33 of this
preamble of this document. These national data are provided as a frame
of reference to compare the results of the baseline proximity analysis,
the baseline risk-based analyses, and the post-control risk-based
analyses.
The results of the proximity demographic 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 African American is
more than double the national average 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 risk-based
demographic analysis, which focuses on populations that have higher
cancer risks, suggests that Hispanic/Latinos and African Americans are
overrepresented at all cancer risk levels greater than 1-in-1 million.
In addition, linguistic isolation increases as the Hispanic/Latino
population increases. At all risk levels, in most cases, populations
living around facilities where the percentage of the population below
the poverty level is 1.5 to 2 times the national average also are above
the national average for African American, Native American, Hispanic/
Latino, or Other/Multiracial. The post-control risk-based demographic
analysis shows that the controls under consideration in this proposal
would reduce the number of people who are exposed to cancer risks
resulting from SOCMI source category emissions 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 significantly, which will
[[Page 25183]]
improve human health of current and future populations that live near
these facilities. After the control has been implemented, there will be
no people who are exposed to cancer risks greater than 100-in-1 million
resulting from SOCMI source category emissions. 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 31 through 33 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. These baseline proximity results are repeated in
Tables 31 through 33 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 African American
(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 31 through 33 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 31
of this preamble), greater than or equal to 50-in-1 million (Table 32
of this preamble), and greater than 100-in-1 million (Table 33 of this
preamble). The risk analysis indicated that emissions from the source
category, prior to the controls we are proposing, expose 2.8 million
people living near 111 facilities to a cancer risk greater than or
equal to 1-in-1 million, 342,000 people living near 21 facilities to a
cancer risk greater than or equal to 50-in-1 million, and 87,000 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 African American (25 percent, 692,000 people)
is well above the average percentage of the national population that is
African American (12 percent). The African American population living
within 10 km of two facilities in Louisiana account for about a quarter
of the total African American 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 proposed controls 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 Native
American 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 Native American 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, 513K 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 342,000 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 African
American with baseline cancer risk greater than or equal to 50-in-1
million resulting from SOCMI source category emissions (19 percent,
65,000 people) is above the national average (12 percent) but is
significantly lower than the percent of the population that is African
American 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 African Americans 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 African Americans with risks greater
than or equal to 50-in-1
[[Page 25184]]
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 (24 percent, 83,000 people) is 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 account
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 Native American 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 that have a percent Native American 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 (14 percent), over 25 years
old without a high school diploma (15 percent), or are linguistically
isolated (5 percent) are similar 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 88,000 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
African American with baseline cancer risk greater than 100-in-1
million resulting from SOCMI source category emissions (15 percent) is
just above the national average (12 percent). The percentage of the
African American 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 (25 percent, 22,000 people) is above the national average (19
percent) and is similar to the share of the population with cancer
risks resulting from SOCMI source category emissions greater than or
equal to 50-in-1 million (24 percent, 83,000 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 Native
American 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.
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 Hispanics
or Latinos are disproportionally overrepresented at all cancer risk
levels. Specifically, the percent 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 a million and 100 in a million risk levels.
Similarly, the African American population is disproportionately
overrepresented at all cancer risk levels in the baseline risk
analysis. The percentage of African American individuals with risks
greater than or equal to 1-in-1 million resulting from SOCMI source
category emissions is twice the national average and 1.25 times the
national average for the percentage with risks greater than 100-in-1
million. 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 populations that is African American, Native
American, Hispanic/Latino, or Other/Multiracial residents 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 31 of this preamble), greater than or
equal to 50-in-1 million (Table 32 of this preamble), and greater than
100-in-1 million (Table 33 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 are in the columns
titled ``Post-Control'' of Tables 31 through 33 of this preamble. In
this analysis, we evaluated how all of the proposed controls and
emission reductions for HON processes described in this action affect
the distribution of risks. This enables us to characterize the post-
control risks and to evaluate whether the proposed action creates or
mitigates potential EJ 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 31 of this
preamble) is reduced from 2.8 million people in the baseline to
approximately 2.5 million people after implementation of the proposed
HON controls. 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 31 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.
[[Page 25185]]
Specifically, percentage of the population with risks greater than or
equal to 1-in-1 million resulting from SOCMI source category emissions
that is African American remains high at 23 percent in the post-control
scenario, but the number of African Americans with risks at or above 1-
in-1 million is reduced by over 100,000 people from 692,000 in the
baseline to 583,000 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 (37 percent versus 19 percent), but the
number of Hispanic/Latino individuals with risks at or above 1-in-1
million is reduced by about 40,000 people from 958,000 in the baseline
to 917,000 in the post-control scenario.
The percent of the population that is Native American 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 Native American population that is more than 2
times the national average. However, the number of Native Americans
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 56,000, from 513,000 to 457,000. 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 50,000, from 561,000 to 513,000. 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 higher in the post-control scenario (9 percent), but the
number of individuals is reduced by 14,000 compared to the baseline,
from 228,000 to 214,000.
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 32
of this preamble) is reduced significantly from 342,000 people in the
baseline to 29,000 after implementation of the proposed controls. 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 African American
decreased in the post-control scenario and is equal to the national
average (12 percent). The number of African Americans with risks at or
above 50-in-1 million is reduced from 65,000 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 24 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
83,000 in the baseline to 9,000 post-control.
Overall, the percent of the population that is Native American 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 Native Americans with risks greater than or equal to 50-in-1
million resulting from SOCMI source category emissions is reduced from
700 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 (14 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 49,000 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
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 33 of this preamble) is
reduced from over 87,000 individuals in the baseline to zero
individuals after application of the proposed SOCMI controls.
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 under consideration in this proposal would
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 2.5 million
people), populations of African Americans, Hispanics/Latinos, 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
342,000 to 29,000), but the population of African Americans 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 87,000 people to 0 people).
[[Page 25186]]
Table 31--Source Category: Comparison of Baseline and Post-Control Demographics of Populations With Cancer Risk
Greater Than or Equal to 1-in-1 Million Resulting From SOCMI Source Category Emissions Living Within 10 km of
Facilities to the National Average and Proximity Demographics
----------------------------------------------------------------------------------------------------------------
Baseline proximity Cancer risk >=1-in-1 million within 10
analysis for pop. km of HON facilities
Demographic group Nationwide average living within 10 ---------------------------------------
for reference km of HON
facilities Baseline Post-control
----------------------------------------------------------------------------------------------------------------
Total Population................ 328M.............. 9,271,798......... 2,798,319......... 2,512,518.
Number of Facilities............ .................. 195............... 111............... 111.
----------------------------------------------------------------------------------------------------------------
Race and Ethnicity by Percent [number of people]
----------------------------------------------------------------------------------------------------------------
White........................... 60 [197M]......... 47 [4.4M]......... 37 [1.04M]........ 37 [919K].
African American................ 12 [40M].......... 25 [2.35M]........ 25 [692K]......... 23 [583K].
Native American................. 0.7 [2M].......... 0.2 [20K]......... 0.2 [6K].......... 0.2 [5K].
Hispanic or Latino (includes 19 [62M].......... 22 [2M]........... 34 [958K]......... 37 [917K].
white and nonwhite).
Other and Multiracial........... 8 [27M]........... 5 [493K].......... 4 [101K].......... 4 [89K].
----------------------------------------------------------------------------------------------------------------
Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level............. 13 [44M].......... 19 [1.75M]........ 18 [513K]......... 18 [457K].
Above Poverty Level............. 87 [284M]......... 81 [7.5M]......... 82 [2.3M]......... 82 [2.1M].
----------------------------------------------------------------------------------------------------------------
Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High 12 [40M].......... 16 [1.5M]......... 20 [561K]......... 20 [513K].
School Diploma.
Over 25 and with a High School 88 [288M]......... 84 [7.8M]......... 80 [2.2M]......... 80 [2M].
Diploma.
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated......... 5 [18M]........... 5 [510K].......... 8 [228K].......... 9 [214K].
----------------------------------------------------------------------------------------------------------------
Notes:
There are 207 HON facilities; however, only 195 of these facilities are included in the proximity
analysis based on available data, which corresponds to 222 EIS facility IDs.
Nationwide population and demographic percentages are based on Census' 2015-2019 American Community
Survey (ACS) 5-year block group averages. Total population count within 10 km is based on 2010 Decennial
Census block population.
To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
unable to estimate population and demographics for that facility.
The sum of individual populations with a demographic category may not add up to total due to rounding.
Table 32--Source Category: Comparison of Baseline and Post-Control Demographics of Populations With Cancer Risk
Greater Than or Equal to 50-in-1 Million Resulting From SOCMI Source Category Emissions Living Within 10 km of
Facilities to the National Average and Proximity Demographics
----------------------------------------------------------------------------------------------------------------
Baseline proximity Cancer risk >=1-in-1 million within 10
analysis for pop. km of HON facilities
Demographic group Nationwide average living within 10 ---------------------------------------
for reference km of HON
facilities Baseline Post-control
----------------------------------------------------------------------------------------------------------------
Total Population................ 328M.............. 9,271,798......... 341,638........... 29,355.
Number of Facilities............ .................. 195............... 21................ 13.
----------------------------------------------------------------------------------------------------------------
Race and Ethnicity by Percent [number of people]
----------------------------------------------------------------------------------------------------------------
White........................... 60 [197M]......... 47 [4.4M]......... 52 [177K]......... 54 [16K].
African American................ 12 [40M].......... 25 [2.35M]........ 19 [65K].......... 12 [4K].
Native American................. 0.7 [2M].......... 0.2 [20K]......... 0.2 [660]......... 0.3 [81].
Hispanic or Latino (includes 19 [62M].......... 22 [2M]........... 24 [83K].......... 29 [9K] .
white and nonwhite).
Other and Multiracial........... 8 [27M]........... 5 [493K].......... 5 [17K]........... 4 [1.2K].
----------------------------------------------------------------------------------------------------------------
Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level............. 13 [44M].......... 19 [1.75M]........ 14 [49K].......... 11 [3.3K].
Above Poverty Level............. 87 [284M]......... 81 [7.5M]......... 86 [293K]......... 89 [26K].
----------------------------------------------------------------------------------------------------------------
Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High 12 [40M].......... 16 [1.5M]......... 15 [50K].......... 12 [4K].
School Diploma.
Over 25 and with a High School 88 [288M]......... 84 [7.8M]......... 85 [291K]......... 88 [26K].
Diploma.
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated......... 5 [18M]........... 5 [510K].......... 5 [15K]........... 3 [766].
----------------------------------------------------------------------------------------------------------------
Notes:
There are 207 HON facilities; however, only 195 of these facilities are included in the proximity
analysis based on available data, which corresponds to 222 EIS facility IDs.
Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
averages. Total population count within 10 km is based on 2010 Decennial Census block population.
To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
unable to estimate population and demographics for that facility.
[[Page 25187]]
The sum of individual populations with a demographic category may not add up to total due to rounding.
Table 33--Source Category: Comparison of Baseline and Post-Control Demographics of Populations With Cancer Risk
Greater Than 100-in-1 Million Resulting From SOCMI Source Category Emissions Living Within 10 km of Facilities
to the National Average and Proximity Demographics
----------------------------------------------------------------------------------------------------------------
Baseline proximity Cancer risk >=1-in-1 million within 10
analysis for pop. km of HON facilities
Demographic group Nationwide average living within 10 ---------------------------------------
for reference km of HON
facilities Baseline Post-control
----------------------------------------------------------------------------------------------------------------
Total Population................ 328M.............. 9,271,798......... 87,464............ 0
Number of Facilities............ .................. 195............... 8................. 0
----------------------------------------------------------------------------------------------------------------
Race and Ethnicity by Percent [number of people]
----------------------------------------------------------------------------------------------------------------
White........................... 60 [197M]......... 47 [4.4M]......... 54 [47K]..........
African American................ 12 [40M].......... 25 [2.35M]........ 15 [13K]..........
Native American................. 0.7 [2M].......... 0.2 [20K]......... 0.2 [202].........
Hispanic or Latino (includes 19 [62M].......... 22 [2M]........... 25 [22K]..........
white and nonwhite).
Other and Multiracial........... 8 [27M]........... 5 [493K].......... 6 [5.5K]..........
----------------------------------------------------------------------------------------------------------------
Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level............. 13 [44M].......... 19 [1.75M]........ 14 [12K]..........
Above Poverty Level............. 87 [284M]......... 81 [7.5M]......... 86 [75K]..........
----------------------------------------------------------------------------------------------------------------
Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High 12 [40M].......... 16 [1.5M]......... 14 [12K]..........
School Diploma.
Over 25 and with a High School 88 [288M]......... 84 [7.8M]......... 86 [75K]..........
Diploma.
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated......... 5 [18M]........... 5 [510K].......... 5 [4K]............
----------------------------------------------------------------------------------------------------------------
Notes:
There are 207 HON facilities; however, only 195 of these facilities are included in the proximity
analysis based on available data, which corresponds to 222 EIS facility IDs.
Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
averages. Total population count within 10 km is based on 2010 Decennial Census block population.
To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
unable to estimate population and demographics for that facility.
The sum of individual populations with a demographic category may not add up to total due to rounding.
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 assessment includes all sources of HAP emissions at each facility
as reported in the NEI (described in section III.C of this preamble).
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 proposed in this 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) Facilities, which is available in the docket for this
action.
The whole-facility demographic analysis post-control results are
shown in Table 34 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 proposed reductions, 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, 78,000 people living around 24
facilities to a cancer risk greater than or equal to 50-in-1 million,
and 2,500 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
500,000 additional people with risks greater than or equal to 1-in-1
million, 29,000 additional people with risks greater than or equal to
50-in-1 million, and 2,500 additional people with risks greater than
100-in-1 million. With the exception of a smaller percentage of
affected Hispanic/Latino individuals (37 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 category population with risks greater than or equal to
1-in-1 million in the post-
[[Page 25188]]
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. The SOCMI 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
2,500 people with post-control risks greater than 100-in-million. The
increased cancer risk for most of these 2,500 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 African American
(29 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 (21 percent,500 individuals),
and the percent of the population that is over 25 years old without a
high school diploma (25 percent, 600 individuals) are above the
national average (13 percent and 12 percent, respectively).
Table 34--Whole Facility: Whole-Facility Post-Control Demographics for HON Facilities by Risk Level for
Populations Living Within 10 km of Facilities
----------------------------------------------------------------------------------------------------------------
Post-control cancer risk for populations within 10 km
Demographic group Nationwide -----------------------------------------------------------
>=1-in-1 million >=50-in-1 million >100-in-1 million
----------------------------------------------------------------------------------------------------------------
Total Population................ 328M.............. 3,119,955......... 78,144............ 2,498.
Number of Facilities............ .................. 140............... 24................ 4.
----------------------------------------------------------------------------------------------------------------
Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White........................... 60 [197M]......... 39 [1.2M]......... 57 [45K].......... 53 [1.3K].
African American................ 12 [40M].......... 24 [760K]......... 14 [11K].......... 29 [727].
Native American................. 0.7 [2M].......... 0.2 [6.5K]........ 0.2 [174]......... 0.0 [1].
Hispanic or Latino (includes 19 [62M].......... 33 [1M]........... 25 [20K].......... 17 [434].
white and nonwhite).
Other and Multiracial........... 8 [27M]........... 4 [113K].......... 4 [3K]............ 1 [22] .
----------------------------------------------------------------------------------------------------------------
Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level............. 13 [44M].......... 18 [576K]......... 14 [11K].......... 21 [531].
Above Poverty Level............. 87 [284M]......... 82 [2.5M]......... 86 [67K].......... 79 [2K] .
----------------------------------------------------------------------------------------------------------------
Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High 12 [40M].......... 20 [614K]......... 16 [12.5K]........ 25 [619].
School Diploma.
Over 25 and with a High School 88 [288M]......... 80 [2.5M]......... 84 [66K].......... 75 [2K].
Diploma.
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated......... 5 [18M]........... 8 [236K].......... 3 [3K]............ 2 [43].
----------------------------------------------------------------------------------------------------------------
Notes:
Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
averages. Total population count within 10 km is based on 2010 Decennial Census block population.
To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
unable to estimate population and demographics for that facility.
The sum of individual populations with a demographic category may not add up to total due to rounding.
3. Neoprene Production Source Category Demographics
For the Neoprene Production source category, the EPA examined the
potential for the one neoprene production facility to pose EJ concerns
to communities both in the baseline and under the control option
considered in this proposal. Specifically, the EPA analyzed how
demographics and risk are distributed both pre- and post-control,
enabling us to address the core questions that are posed in the EPA's
2016 Technical Guidance for Assessing Environmental Justice in
Regulatory Analysis. In conducting this analysis, we considered key
variables highlighted in the guidance including minority populations
(people of color and Hispanic or Latino), low-income populations, and/
or indigenous peoples. 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
Facilities, available in the docket for this action.
To examine the potential for EJ concerns in the pre-control
baseline, the EPA conducted a baseline proximity analysis, baseline
risk-based analysis, and post-control 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
proposed rule. 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 African
[[Page 25189]]
American 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 African
Americans are disproportionally overrepresented at all cancer risk
levels resulting from Neoprene Production source category emissions
(Percent African Americans ranges 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 under consideration for Neoprene Production source category in
this proposal 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 demographics of this
population in the post-control risk-based analysis are similar to the
baseline population. 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 90 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 35 through 37 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 live within 5
km of the one neoprene facility. The results of the proximity
demographic analysis indicate that the percent of the population that
is African American (56 percent, 16,000 people) is more than four times
the national average (12 percent). The percent 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 35 through 37 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 35 of this preamble), greater than or equal to
50-in-1 million (Table 36 of this preamble), and greater than 100-in-1
million Table 37 of this preamble) in the absence of the reductions we
are proposing.
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 African American (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 proposing, 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 African
Americans; that percent is almost 6 times the national average (68
percent versus 12 percent nationally). The percent of the population
that is below the poverty line is more than double the national average
(27 percent versus 13 percent nationally), and the percent 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 facility with a cancer risk resulting from Neoprene Production
source category emissions greater than 100-in-1 million. The percent of
the population that is African American with baseline cancer risk
greater than 100-in-1 million (85 percent, 1,753 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 African Americans are
disproportionally overrepresented at all cancer risk levels.
Specifically, at all risk levels, the percent of the population that is
African American 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 35 of this preamble), greater than or equal to
50-in-1 million (Table 36 of this preamble), and greater than 100-in-1
million (Table 37 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
[[Page 25190]]
analysis are in the columns titled ``Post-Control'' of Tables 35
through 37 of this preamble. In this analysis, we evaluated how all of
the proposed controls and emission reductions for the Neoprene
Production source category described in this action affect the
distribution of risks. This enables us to characterize the post-control
risks and to evaluate whether the proposed action creates or mitigates
potential EJ 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 35 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 35 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 African American (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 48,000.
The risk analysis indicated that the number of people living within
5 km of the facility and exposed to risks resulting from Neoprene
Production source category emissions greater than or equal to 50-in-1
million (Table 36 of this preamble) is reduced significantly from about
13,000 people in the baseline to 700 people after implementation of the
proposed controls. This represents more than a 90 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 36 of this preamble) is almost entirely
African American (99 percent). The number of African Americans with
risks greater than or equal to 50-in-1 million is reduced from about
9,000 in the baseline to 700 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 200 people
post-control.
The risk analysis indicated that the number of people living within
5 km of the facility and exposed to risks resulting from Neoprene
Production source category emissions greater than 100-in-1 million
(Table 37 of this preamble) is reduced from over 2,000 people in the
baseline to zero people after application of the proposed controls.
Therefore, for the post-control risk-based demographics, no people with
risks resulting from Neoprene Production source category emissions
above 100-in-1 million.
In summary, as shown in the post-control risk-based demographic
analysis, the controls under consideration in this proposal 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, African Americans 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 90 percent at all
distances. In the post-control population with risks greater than or
equal to 50-in-1 million, African Americans 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.
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 proposed in this 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 category risk and Neoprene Production category risk at
this facility. Based on whole-facility emissions, there are a total of
about 47,000 people living within 10 km (~6.2 miles) with risks greater
than or equal to 1-in-1 million after controls, which is unchanged from
the baseline. There are 86,000 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 893,000
people in the baseline. The population within 10 km with post-control
whole-facility risks of greater than or equal to 1-in-1 million is 55
percent African American, and 19 percent are below the poverty level.
Based on whole-facility emissions there are a total of about 2,000
people remaining after controls living within 10 km and 50 km of the
neoprene facility with risks greater than or equal to 50-in-1 million
(a reduction of 83 percent from the baseline of 16,000 people). This
population is 83 percent African American and 32 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 10 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 African American, and 33 percent are
below the poverty level. We note that as further discussed in section
III.C.7 of this preamble, the EPA is proposing a 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 100-in-1 million and
that 0 people (rather than 300 people as shown in this analysis) will
remain with risks greater than 100-in-1 million.
[[Page 25191]]
Table 35--Source Category: Comparison of Baseline and Post-Control Demographics of Populations With Cancer Risk
Greater Than or Equal to 1-in-1 Million Living Within 5 km of the Neoprene Production Facility to the National
Average and the Proximity Demographics
----------------------------------------------------------------------------------------------------------------
Total Cancer risk >=1-in-1
population million within 5 km of
living neoprene facility
Demographic group Nationwide within 5 -------------------------
km of
neoprene Baseline Post-
facility control
----------------------------------------------------------------------------------------------------------------
Total population............................................ 328M 28,571 28,571 28,571.
Number of Facilities........................................ ........... 1 1 1.
----------------------------------------------------------------------------------------------------------------
Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White....................................................... 60 [197M] 35 [10K] 35 [10K] 35 [10K].
African American............................................ 12 [40M] 56 [16K] 56 [16K] 56 [16K].
Native American............................................. 0.7 [2M] 0.0 0.0 0.0.
Hispanic or Latino (includes white and nonwhite)............ 19 [62M] 5 [1.5K] 5 [1.5K] 5 [1.5K].
Other and Multiracial....................................... 8 [27M] 3 [900] 3 [900] 3 [900].
----------------------------------------------------------------------------------------------------------------
Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level......................................... 13 [44M] 23 [6.5K] 23 [6.5K] 23 [6.5K].
Above Poverty Level......................................... 87 [284M] 77 [22K] 77 [22K] 77 [22K].
----------------------------------------------------------------------------------------------------------------
Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma................... 12 [40M] 16 [4.6K] 16 [4.6K] 16 [4.6K].
Over 25 and with a High School Diploma...................... 88 [288M] 84 [24K] 84 [24K] 84 [24K].
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated..................................... 5 [18M] 1 [300] 1 [300] 1 [300].
----------------------------------------------------------------------------------------------------------------
Notes:
Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
averages. Total population count within 5 km is based on 2010 Decennial Census block population.
To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
unable to estimate population and demographics for that facility.
The sum of individual populations with a demographic category may not add up to total due to rounding.
Table 36--Source Category: Comparison of Baseline and Post-Control Demographics of Populations With Cancer Risk
Greater Than or Equal to 50-in-1 Million Living Within 5 km of the Neoprene Facility to the National Average and
the Proximity Demographics
----------------------------------------------------------------------------------------------------------------
Total Cancer risk >=50-in-1
population million within 5 km of
living the neoprene facility
Demographic group Nationwide within 5 -------------------------
km of the
neoprene Baseline Post-
facility control
----------------------------------------------------------------------------------------------------------------
Total Population............................................ 328M 28,571 12,801 727.
Number of Facilities........................................ ........... 1 1 1.
----------------------------------------------------------------------------------------------------------------
Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White....................................................... 60 [197M] 35 [10K] 26 [3.3K] 1 [<100].
African American............................................ 12 [40M] 56 [16K] 68 [8.6K] 99 [700].
Native American............................................. 0.7 [2M] 0.0 0.0 0.0 .
Hispanic or Latino (includes white and nonwhite)............ 19 [62M] 5 [1.5K] 4 [500] 0 .
Other and Multiracial....................................... 8 [27M] 3 [900] 2 [200] 0 .
----------------------------------------------------------------------------------------------------------------
Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level......................................... 13 [44M] 23 [6.5K] 27 [3.4K] 33 [200].
Above Poverty Level......................................... 87 [284M] 77 [22K] 73 [9.3K] 67 [500].
----------------------------------------------------------------------------------------------------------------
Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma................... 12 [40M] 16 [4.6K] 18 [2.3K] 12 [<100].
Over 25 and with a High School Diploma...................... 88 [288M] 84 [24K] 82 [10.5K] 88 [600].
----------------------------------------------------------------------------------------------------------------
[[Page 25192]]
Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated..................................... 5 [18M] 1 [300] 1 [<100] 0 .
----------------------------------------------------------------------------------------------------------------
Notes:
Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
averages. Total population count within 5 km is based on 2010 Decennial Census block population.
To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
unable to estimate population and demographics for that facility.
The sum of individual populations with a demographic category may not add up to total due to rounding.
Table 37--Source Category: Comparison of Baseline and Post-Control Demographics of Populations With Cancer Risk
Greater Than 100-in-1 Million Living Within 5 km of the Neoprene Facility to the National Average and the
Proximity Demographics
----------------------------------------------------------------------------------------------------------------
Total Cancer risk >100-in-1
population million within 5 km of
living the neoprene facility
Demographic group Nationwide within 5 -------------------------
km of the
neoprene Baseline Post-
facility control
----------------------------------------------------------------------------------------------------------------
Total population............................................ 328M 28,571 2,052 0
Number of Facilities........................................ ........... 1 1 0
----------------------------------------------------------------------------------------------------------------
Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White....................................................... 60 [197M] 35 [10K] 11 [200] 0
African American............................................ 12 [40M] 56 [16K] 85 [1.8K] 0
Native American............................................. 0.7 [2M] 0.0 0.0 0.0
Hispanic or Latino (includes white and nonwhite)............ 19 [62M] 5 [1.5K] 3 [<100] 0
Other and Multiracial....................................... 8 [27M] 3 [900] 0 0
----------------------------------------------------------------------------------------------------------------
Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level......................................... 13 [44M] 23 [6.5K] 31 [600] 0
Above Poverty Level......................................... 87 [284M] 77 [22K] 69 [1.4K] 0
----------------------------------------------------------------------------------------------------------------
Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma................... 12 [40M] 16 [4.6K] 14 [300] 0
Over 25 and with a High School Diploma...................... 88 [288M] 84 [24K] 86 [1.8K] 0
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated..................................... 5 [18M] 1 [300] 0 0
----------------------------------------------------------------------------------------------------------------
Notes:
Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
averages. Total population count within 5 km is based on 2010 Decennial Census block population.
To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
unable to estimate population and demographics for that facility.
The sum of individual populations with a demographic category may not add up to total due to rounding.
4. P&R I and P&R II Source Categories Demographics
As stated above, for P&R I and P&R II, other than the Neoprene
Production source category within P&R I, we have not conducted a risk
assessment for this proposal. Therefore, to examine the potential for
any EJ 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 10 km (~6.2 miles) of the
[[Page 25193]]
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 Hazardous Organic
NESHAP (HON) Facilities, which is available in the docket for this
action.
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: African American
(37 percent versus 12 percent nationally), Hispanic/Latino (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: Native
American (0.9 percent versus 0.7 percent nationally), Hispanic/Latino
(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 38 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, which is available
in the docket for this action.
Table 38--Proximity Demographic Assessment Results for Polymers and Resins I and II Facilities
----------------------------------------------------------------------------------------------------------------
P&R I: population P&R II: population
Demographic group Nationwide average for within 5 km of 18 within 5 km of 5
reference facilities facilities
----------------------------------------------------------------------------------------------------------------
Total Population..................... 328M................... 627,823................ 124,050
----------------------------------------------------------------------------------------------------------------
Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White................................ 60 [197M].............. 35 [218K].............. 62 [76K].
African American..................... 12 [40M]............... 37 [234K].............. 5 [7K].
Native American...................... 0.7 [2M]............... 0.2 [1K]............... 0.9 [1K].
Hispanic or Latino (includes white 19 [62M]............... 24 [150K].............. 27 [34K].
and nonwhite).
Other and Multiracial................ 8 [27M]................ 4 [24K]................ 5 [6K].
----------------------------------------------------------------------------------------------------------------
Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.................. 13 [44M]............... 24 [150K].............. 13 [16K].
Above Poverty Level.................. 87 [284M].............. 76 [478K].............. 87 [108K].
----------------------------------------------------------------------------------------------------------------
Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School 12 [40M]............... 21 [130K].............. 13 [16K].
Diploma.
Over 25 and with a High School 88 [288M].............. 79 [498K].............. 87 [108K].
Diploma.
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.............. 5 [18M]................ 7 [43K]................ 2 [3K].
----------------------------------------------------------------------------------------------------------------
Notes:
Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
averages. Total population count within 10 km is based on 2010 Decennial Census block population.
To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
The sum of individual populations with a demographic category may not add up to total due to rounding.
5. Proximity Demographics Analysis for NSPS Subpart VVb
Consistent with the EPA's commitment to integrating EJ in the
Agency's actions, and following the directives set forth in multiple
Executive Orders as well as CAA section 111(b)(1)(B), the Agency has
carefully considered the impacts of the proposed NSPS subpart VVb on
communities with EJ concerns. The proposed 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.
Executive Order 12898 directs the EPA to identify the populations
of concern who are most likely to experience unequal burdens from
environmental harms; specifically, minority populations, low-income
populations, and indigenous peoples (59 FR 7629, February 16, 1994).
Additionally, Executive Order 13985 is intended to advance racial
equity and support underserved communities through Federal government
actions (86 FR 7009, January 20, 2021). The EPA defines EJ as ``the
fair treatment and meaningful involvement of all people regardless of
race, color, national origin, or income with respect to the
development, implementation, and enforcement of environmental laws,
regulations, and policies.'' \170\ The EPA further defines the term
fair treatment to mean that ``no group of people should bear a
disproportionate burden of environmental harms and risks, including
those resulting from the negative environmental consequences of
industrial, governmental, and commercial operations or programs and
policies.'' In recognizing that minority and low-income populations
often bear an unequal burden of environmental harms and risks, the EPA
continues to consider ways of protecting them from adverse public
health and environmental effects of air pollution.
---------------------------------------------------------------------------
\170\ See footnote 168.
---------------------------------------------------------------------------
The locations of the new, modified, and reconstructed sources that
will become subject to NSPS subpart VVb are not known. Therefore, to
examine
[[Page 25194]]
the potential for any EJ issues that might be associated with the
proposed NSPS subpart VVb, we performed a proximity demographic
analysis for 575 existing facilities that are currently subject to NSPS
subparts VV or VVa. These 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 African American is
double the national average (24 percent versus 12 percent). 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
African American 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.
Table 39--Proximity Demographic Assessment Results for Existing Facilities Subject to NSPS Subparts VV and VVa
----------------------------------------------------------------------------------------------------------------
Population within 50 km Population within 5 km
Demographic group Nationwide of 575 facilities of 575 facilities
----------------------------------------------------------------------------------------------------------------
Total Population..................... 328,016,242............ 140,946,443............ 8,084,246
----------------------------------------------------------------------------------------------------------------
Race and Ethnicity by Percent
----------------------------------------------------------------------------------------------------------------
White................................ 60..................... 62..................... 50
African American..................... 12..................... 15..................... 24
Native American...................... 0.7.................... 0.4.................... 0.4
Hispanic or Latino (includes white 19..................... 15..................... 20
and nonwhite).
Other and Multiracial................ 8...................... 8...................... 5
----------------------------------------------------------------------------------------------------------------
Income by Percent
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.................. 13..................... 14..................... 20
Above Poverty Level.................. 87..................... 86..................... 80
----------------------------------------------------------------------------------------------------------------
Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School 12..................... 12..................... 17
Diploma.
Over 25 and with a High School 88..................... 88..................... 83
Diploma.
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated by Percent
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.............. 5...................... 5...................... 6
----------------------------------------------------------------------------------------------------------------
Notes:
The nationwide population count and all demographic percentages are based on the Census' 2015-2019
American Community Survey five-year block group averages and include Puerto Rico. Demographic percentages
based on different averages may differ. The total population counts are based on the 2010 Decennial Census
block populations.
To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
category for these analyses. A person is identified as one of five racial/ethnic categories above: White,
African American, Native American, Other and Multiracial, or Hispanic/Latino. A person who identifies as
Hispanic or Latino is counted as Hispanic/Latino for this analysis, regardless of what race this person may
have also identified as in the Census.
The proposed 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. NSPS subpart VVb will
result in reduced VOC emissions by requiring the same requirements in
NSPS subpart VVa plus requiring 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. For each of these requirements, we are proposing skip periods
for good performance.
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, which is
available in the docket for this action.
6. Proximity Demographics Analysis for NSPS Subparts IIIa, NNNa, and
RRRa
Consistent with the EPA's commitment to integrating EJ in the
Agency's actions, and following the directives set forth in multiple
Executive Orders as well as CAA section 111(b)(1)(B), the Agency has
carefully considered the impacts of the proposed NSPS subparts IIIa,
NNNa, and RRRa on communities with EJ concerns. The proposed 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.
Executive Order 12898 directs the EPA to identify the populations
of concern who are most likely to experience unequal burdens from
environmental harms; specifically, minority populations, low-income
populations, and indigenous peoples (59 FR 7629, February 16, 1994).
Additionally, Executive Order 13985 is intended to advance racial
equity and support underserved communities through Federal government
actions (86 FR 7009, January 20, 2021). The EPA defines EJ as ``the
fair treatment and meaningful involvement of all people regardless of
race, color, national origin, or income with respect to the
development, implementation, and
[[Page 25195]]
enforcement of environmental laws, regulations, and policies.'' \171\
The EPA further defines the term fair treatment to mean that ``no group
of people should bear a disproportionate burden of environmental harms
and risks, including those resulting from the negative environmental
consequences of industrial, governmental, and commercial operations or
programs and policies.'' In recognizing that minority and low-income
populations often bear an unequal burden of environmental harms and
risks, the EPA continues to consider ways of protecting them from
adverse public health and environmental effects of air pollution.
---------------------------------------------------------------------------
\171\ See footnote 168.
---------------------------------------------------------------------------
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 examine the potential for any EJ issues that might
be associated with the proposed subparts, we performed a proximity
demographic analysis for 266 existing facilities that are currently
subject to NSPS subpart III, NNN, or RRR. These represent facilities
that might modify or reconstruct in the future and become subject to
the proposed 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 African American is
almost double the national average (23 percent versus 12 percent). In
addition, the percent 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 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 African American 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.
Table 40--Proximity Demographic Assessment Results for Existing Facilities Subject to NSPS Subparts III, NNN, or
RRR
----------------------------------------------------------------------------------------------------------------
Population
within 50 km Population
Demographic group Nationwide of 266 within 5 km of
facilities 266 facilities
----------------------------------------------------------------------------------------------------------------
Total Population................................................ 328,016,242 96,017,770 4,624,154
----------------------------------------------------------------------------------------------------------------
Race and Ethnicity by Percent
----------------------------------------------------------------------------------------------------------------
White........................................................... 60 59 48
African American................................................ 12 18 23
Native American................................................. 0.7 0.4 0.4
Hispanic or Latino (includes white and nonwhite)................ 19 15 23
Other and Multiracial........................................... 8 7 5
----------------------------------------------------------------------------------------------------------------
Income by Percent
----------------------------------------------------------------------------------------------------------------
Below Poverty Level............................................. 13 14 20
Above Poverty Level............................................. 87 86 80
----------------------------------------------------------------------------------------------------------------
Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma....................... 12 12 17
Over 25 and with a High School Diploma.......................... 88 88 83
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated by Percent
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated......................................... 5 5 6
----------------------------------------------------------------------------------------------------------------
Notes:
The nationwide population count and all demographic percentages are based on the Census' 2015-2019
American Community Survey five-year block group averages and include Puerto Rico. Demographic percentages
based on different averages may differ. The total population counts are based on the 2010 Decennial Census
block populations.
To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
category for these analyses. A person is identified as one of five racial/ethnic categories above: White,
African American, Native American, Other and Multiracial, or Hispanic/Latino. A person who identifies as
Hispanic or Latino is counted as Hispanic/Latino for this analysis, regardless of what race this person may
have also identified as in the Census.
The proposed 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
proposed NSPS subparts IIIa, NNNa, and RRRa will result in reduced VOC
emissions by requiring all vent streams from an affected facility to be
controlled, 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, and prohibiting an owner or operator from bypassing the APCD
at any time, and if a bypass is used, it is considered a violation. In
addition, we are proposing the same operating and monitoring
requirements for flares that we are proposing for flares subject to the
HON, the same work practice standards for maintenance vents that we are
[[Page 25196]]
proposing for HON process vents, and the same monitoring requirements
that we are proposing for HON process vents for adsorbers that cannot
be regenerated and regenerative adsorbers that are regenerated offsite
(see section III.C.3.b of this preamble).
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, which is
available in the docket for this action.
G. What analysis of children's environmental health did we conduct?
This action proposes to address risk from, among other HAP, EtO and
chloroprene. In addition, the EPA's Policy on Children's Health \172\
also applies to this action. Accordingly, we have evaluated the
environmental health or safety effects of EtO and chloroprene emissions
and exposures on children.
---------------------------------------------------------------------------
\172\ Children's Health Policy Available at: https://www.epa.gov/children/childrens-health-policy-and-plan.
---------------------------------------------------------------------------
Because EtO and chloroprene are mutagenic (i.e., they can damage
DNA), children are expected to be more susceptible to their harmful
effects. To take this into account, as part of the risk assessment in
support of this rulemaking, the EPA followed its guidelines \173\ and
applied age-dependent adjustment factors (ADAFs) for childhood
exposures (from birth up to 16 years of age). With the ADAF applied to
account for greater susceptibility of children, the adjusted EtO
inhalation URE is 5 x 10-\3\ per [micro]g/m\3\ and the
adjusted chloroprene inhalation URE is 4.8 x 10-\4\ per
[micro]g/m\3\. It should be noted that, because EtO and chloroprene are
mutagenic, emission reductions proposed in this preamble will be
particularly beneficial to children. The results of the risk assessment
are contained in sections III.A and B of this preamble and further
documented in the risk reports, Residual Risk Assessment for the SOCMI
Source Category in Support of the 2023 Risk and Technology Review
Proposed Rule and Residual Risk Assessment for the Polymers & Resins I
Neoprene Production Source Category in Support of the 2023 Risk and
Technology Review Proposed Rule, which are available in the docket for
this rulemaking.
---------------------------------------------------------------------------
\173\ 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.
---------------------------------------------------------------------------
V. Request for Comments
We solicit comments on this proposed action. In addition to general
comments on this proposed action, we are also interested in additional
data that may improve the analyses. We are specifically interested in
receiving any information regarding developments in practices,
processes, and control technologies that reduce emissions. We are also
interested in receiving information on costs, emissions, and product
recovery and we request comment on how to address the non-monetized
costs and benefits of the proposed rule. We request comment on data and
approaches to monetize the health benefits of reducing exposure to
ethylene oxide, chloroprene, benzene, 1,3-butadiene, ethylene
dichloride, vinyl chloride, chlorine, maleic anhydride, and acrolein.
For our production estimates, we request comment on the assumptions of
the simulation model and their consistency with market conditions and
dynamics. We welcome specific comment on impacts on downstream
industries and markets, including prices for medical supplies, foods,
microchips, semiconductors, gasoline, or other products. In addition,
we request estimates of any potential loss of production while bringing
facilities into compliance and forgone returns due to displaced
investment. Finally, the EPA attempted to ensure that the SSM
provisions we are proposing to eliminate are inappropriate,
unnecessary, or redundant in the absence of the SSM exemption and are
specifically seeking comment on whether we have successfully done so.
With respect to EtO emissions from equipment leaks, given the
uncertainty of emissions from these fugitive sources and that they
drive risk for a number of HON facilities (i.e., seven HON facilities
present >=100-in-1 million cancer risk from emissions of EtO from
equipment leaks at HON processes), the EPA is also soliciting comment
on whether additional control options should be considered for
equipment leaks beyond those discussed in section III.B.2.a.ii of this
preamble, which proposes that valves, connectors, and pumps in EtO
service be monitored monthly using EPA Method 21 of 40 CFR part 60,
appendix A-7, with leak definitions of 100 ppm, 100 ppm, and 500 ppm,
respectively. In particular, the EPA is aware of a number of additional
technologies used by other regulated industries that could be
implemented to monitor and/or reduce leaks of EtO, including requiring
use of ``leakless'' (i.e., low-emitting) equipment for valves and pumps
in EtO service, use of optical gas imaging (OGI) (i.e., use of a
thermal infrared camera) to find large leaks faster, and use of leak
detection sensor networks (LDSNs) that could potentially identify leaks
of EtO at HON facilities.\174\ OGI refers to the creation of images of
gas emissions through thermal infrared cameras. While the application,
specification, and target gases of an OGI instrument may differ, the
general function of an OGI camera is to detect the infrared energy of
the target gas and filter out the light outside of the infrared
frequency range to create an image of the target gas plume. In the
context of leak detection, a hand-held OGI camera can create a video
image of a plume of gas emanating from a leak. A LDSN comprises a
network of leak detection sensor nodes installed to provide coverage of
all LDAR applicable components in a process unit and an accompanying
analytics platform for identifying potential leak source locations. A
short-term excursion of an individual sensor's output above a set
baseline level would indicate a possible leak. Facilities can
investigate the possible leak within the potential leak source
location. The network, analytics platform, and detection response
framework are generally designed to enable timely detection of
significant emissions so that facilities can more rapidly mitigate
leaks.
---------------------------------------------------------------------------
\174\ See, e.g., 40 CFR 60.18(g), 40 CFR 61.65(b)(8), 40 CFR
63.11(c), and 40 CFR 63.11956; U.S. Envtl. Prot. Agency, Standards
of Performance for New, Reconstructed, and Modified Sources and
Emissions Guidelines for Existing Sources: Oil and Natural Gas
Sector Climate Review, 87 FR 74,702 (Dec. 6, 2022); Notice of Final
for Approval of Alternative Means of Emission Limitation (88 FR
8844, February 10, 2023).
---------------------------------------------------------------------------
As EPA does not have sufficient information to evaluate potential
additional HAP reductions that may be realized by these technologies in
the chemical sector, we solicit comment on the emissions reductions
that have been or could be achieved by use of ``leakless'' valves and
pumps, use of OGI, and use of LDSNs, the costs and cost-effectiveness
of applying these technologies, including any cost-effectiveness
comparisons of applying the technologies for different components and
at different frequencies, and any relevant available data and studies.
We also request comment on whether and how the application of these
technologies would reduce risk, and whether and how EPA should consider
application of these technologies to reinforce or enhance the proposed
[[Page 25197]]
equipment leak control requirements. EPA also requests comments on ways
to streamline approval of alternative LDAR programs, use of remote
sensing techniques, use of sensor networks, or other alternatives for
detection of equipment leaks.
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 13563: Improving Regulation and Regulatory Review
Under section 3(f)(1) of Executive Order 12866, this action is a
significant regulatory action that was submitted to the Office of
Management and Budget (OMB) for review. Any changes made in response to
recommendations received as part of Executive Order 12866 review have
been documented in the docket. The EPA prepared an analysis of the
potential costs and benefits associated with this action. This
analysis, the Regulatory Impact Analysis, is available in the docket
for this action.
To satisfy requirements of E.O. 12866, the EPA projected the
emissions reductions, costs, and benefits that may result from these
proposed rulemakings. These results are presented in detail in the
regulatory impact analysis (RIA) accompanying this proposal developed
in response to E.O. 12866. We present these results for each of the 10
subparts included in this proposed action, and also cumulatively. This
action is economically significant according to E.O. 12866 due to the
proposed amendments to the HON. The RIA focuses on the elements of the
proposed rulemaking that are likely to result in quantifiable cost or
emissions changes compared to a baseline without the proposal that
incorporates changes to regulatory requirements. We estimated the cost,
emissions, and benefits for the 2024 to 2038 period. We show the PV and
EAV of costs, benefits, and net benefits of this action in 2021
dollars.
The initial analysis year in the RIA is 2024 because we assume the
large majority of impacts associated with the proposed rulemakings will
begin in that year. The NSPS will take effect immediately upon the
effective date of the final rule (i.e., 60 days after publication of
the final rule in the Federal Register) and impact sources constructed
after publication of the proposed rule, but these impacts are much
lower than those of the other three NESHAP rulemakings in this action.
The other three rules, all under the provisions of CAA section 112,
will also take effect 60 days after publication of the final rule in
the Federal Register, but not require compliance with new requirements
in some cases until three years after the effective date). Therefore,
their impacts (at least the great majority of them) will begin in 2024.
The final analysis year for benefits and costs is 2038, which allows us
to provide 15 years of projected impacts after all of these rules are
assumed to require compliance.
The cost analysis presented in the RIA reflects a nationwide
engineering analysis of compliance cost and emissions reductions, of
which there are two main components. The first component is a set of
representative or model plants for each regulated facility, segment,
and control option. The characteristics of the model plant include
typical equipment, operating characteristics, and representative
factors including baseline emissions and the costs, emissions
reductions, and product recovery resulting from each control option.
The second component is a set of projections of data for affected
facilities, distinguished by vintage, year, and other necessary
attributes (e.g., precise content of material in storage vessels).
Impacts are calculated by setting parameters on how and when affected
facilities are assumed to respond to a particular regulatory regime,
multiplying data by model plant cost and emissions estimates,
differencing from the baseline scenario, and then summing to the
desired level of aggregation. In addition to emissions reductions, some
control options result in product recovery, which can then be sold
where possible. Where applicable, we present projected compliance costs
with and without the projected revenues from product recovery.
The EPA expects health benefits due to the emissions reductions
projected under these proposed rulemakings. We expect that HAP emission
reductions will improve health and welfare associated with exposure by
those affected by these emissions. In addition, the EPA expects that
VOC emission reductions that will occur concurrent with the reductions
of HAP emissions will improve air quality and are likely to improve
health and welfare associated with exposure to ozone, PM2.5,
SO2, and HAP. The EPA also expects disbenefits from
secondary increases of CO2, NOX, CO, and benefits
from reductions in methane emissions associated with the control
options included in the cost analysis. We estimate the social benefits
of GHG reductions expected to occur as a result of the proposed
standards using estimates of the social cost of greenhouse gases (SC-
GHG),\175\ specifically using the social cost of carbon (SC-
CO2), social cost of methane (SC-CH4), and social
cost of nitrous oxide (SC-N2O). The SC-GHG is the monetary
value of the net harm to society associated with a marginal increase in
GHG emissions in a given year, or the benefit of avoiding that
increase. In principle, SC-GHG includes the value of all climate change
impacts (both negative and positive), including (but not limited to)
changes in net agricultural productivity, human health effects,
property damage from increased flood risk and natural disasters,
disruption of energy systems, risk of conflict, environmental
migration, and the value of ecosystem services. The SC-GHG, therefore,
reflects the societal value of reducing emissions of the gas in
question by one metric ton and is the theoretically appropriate value
to use in conducting benefit-cost analyses of policies that affect GHG
emissions. In practice, data and modeling limitations naturally
restrain the ability of SC-GHG estimates to include all the important
physical, ecological, and economic impacts of climate change, such that
the estimates are a partial accounting of climate change impacts and
will therefore tend to be underestimates of the marginal benefits of
abatement. The EPA and other Federal agencies began regularly
incorporating SC-GHG estimates in their benefit-cost analyses conducted
under Executive Order (E.O.) 12866 \176\ since 2008, following a Ninth
Circuit Court of Appeals remand of a rule for failing to monetize the
benefits of reducing GHG emissions in that rulemaking process. We
conduct such
[[Page 25198]]
an analysis to monetize the benefits of reducing GHG emissions (or
disbenefits, if these emissions increase) for this proposal as the EPA
has done for recent rulemakings (e.g., the recently promulgated Good
Neighbor rule).
---------------------------------------------------------------------------
\175\ Estimates of the social cost of greenhouse gases are gas-
specific (e.g., social cost of carbon (SC-CO2), social
cost of methane (SC-CH4), social cost of nitrous oxide
(SC-N2O)), but collectively they are referenced as the
social cost of greenhouse gases (SC-GHG).
\176\ Presidents since the 1970s have issued executive orders
requiring agencies to conduct analysis of the economic consequences
of regulations as part of the rulemaking development process. E.O.
12866, released in 1993 and still in effect today, requires that for
all significant regulatory actions, an agency provide an assessment
of the potential costs and benefits of the regulatory action, and
that this assessment include a quantification of benefits and costs
to the extent feasible. Many statutes also require agencies to
conduct at least some of the same analyses required under E.O.
12866, such as the Energy Policy and Conservation Act, which
mandates the setting of fuel economy regulations. For purposes of
this action, monetized climate benefits are presented for purposes
of providing a complete benefit-cost analysis under E.O. 12866 and
other relevant executive orders. The estimates of change in GHG
emissions and the monetized benefits associated with those changes
play no part in the record basis for this action.
---------------------------------------------------------------------------
Discussion of the monetized and non-monetized benefits and climate
disbenefits can be found in Chapter 4 of the RIA which is available in
the docket for this rulemaking.
Tables 41 through 45 of this preamble present the emission changes,
and PV and EAV of the projected monetized benefits, compliance costs,
and net benefits over the 2024 to 2038 period under the proposed
rulemaking for each subpart. Table 46 of this preamble presents the
same results for the cumulative impact of these rulemakings. All
discounting of impacts presented, except for compliance costs, uses
discount rates of 3 and 7 percent.
Table 41--Monetized Benefits, Costs, and Net Benefits of the Proposed HON Amendments, 2024 Through 2038
[Dollar estimates in millions of 2021 dollars] \a\
----------------------------------------------------------------------------------------------------------------
3 Percent discount rate 7 Percent discount rate
-------------------------------------------------------------------------------
PV EAV PV EAV
----------------------------------------------------------------------------------------------------------------
Benefits \b\.................... $78 and $690...... $6.5 and $58...... $53 and $470...... $5.8 and $51.
Climate Disbenefits (3 percent) $(25.4)........... $(2.1)............ $(25.4)........... $(2.1).
\c\.
Net Compliance Costs \d\........ $1,385............ $116.............. $922.............. $101.
Compliance Costs................ $1,393............ $117.............. $927.............. $102.
Value of Product Recovery....... $8................ $1................ $5................ $0.8.
Net Benefits.................... $(1,280) and $(107) and $(56).. $(844) and $(427). $(93) and $(48).
$(670).
----------------------------------------------------------------------------------------------------------------
Nonmonetized Benefits: HAP emissions reductions of 5,726 tpy including 58 tpy reduction in ethylene oxide
emissions. Health effects of reduced exposure to ethylene oxide and also chloroprene, benzene, 1,3-butadiene,
vinyl chloride, ethylene dichloride, chlorine, maleic anhydride, and acrolein.
----------------------------------------------------------------------------------------------------------------
\a\ Values rounded to two significant figures. Totals may not appear to add correctly due to rounding. Short
tons are standard English tons (2,000 pounds).
\b\ Monetized benefits include ozone related health benefits associated with reductions in VOC emissions. The
health benefits are associated with several point estimates and are presented at real discount rates of 3 and
7 percent. The two benefits estimates are separated by the word ``and'' to signify that they are two separate
estimates. The estimates do not represent lower- and upper-bound estimates. Benefits from annual HAP
reductions and VOC reductions outside of the ozone season remain unmonetized and are thus not reflected in the
table. Climate benefits and disbenefits are estimated at a real discount rate of 3 percent. The unmonetized
effects also include disbenefits resulting from the secondary impact of an increase in CO emissions. Please
see Chapter 4 of the RIA for more discussion of the health and climate benefits and disbenefits.
\c\ Climate benefits and disbenefits are based on changes (decreases and increases) in CO2, methane and N2O
emissions and are calculated using four different estimates of the social cost of carbon (SC-GHG) (model
average at 2.5 percent, 3 percent, and 5 percent discount rates; 95th percentile at 3 percent discount rate).
For the presentational purposes of this table, we show the benefits and disbenefits associated with the
average SC-GHG at a 3 percent discount rate, but the Agency does not have a single central SC-GHG point
estimate. We emphasize the importance and value of considering the disbenefits calculated using all four SC-
GHG estimates. As discussed in Chapter 4 of the RIA, a consideration of climate disbenefits calculated using
discount rates below 3 percent, including 2 percent and lower, is also warranted when discounting
intergenerational impacts. The use of parentheses surrounding a number denotes a negative value for that
number. For climate disbenefits, a negative disbenefit is a benefit (and thus a positive value).
\d\ Net compliance costs are the rulemaking costs minus the value of recovered product. A negative net
compliance costs occurs when the value of the recovered product exceeds the compliance costs.
Table 42--Monetized Benefits, Compliance Costs, and Net Benefits of the Proposed P&R I Amendments, 2024 Through
2038
[Dollar estimates in millions of 2021 dollars] \a\
----------------------------------------------------------------------------------------------------------------
3 Percent discount rate 7 Percent discount rate
-------------------------------------------------------------------------------
PV EAV PV EAV
----------------------------------------------------------------------------------------------------------------
Benefits \b\.................... $2.6 and $23...... $0.22 and $1.9.... $1.8 and $16...... $0.19 and $1.7.
Climate Disbenefits (3 percent) $40.5............. $3.4.............. $40.5............. $3.4.
\c\.
Net Compliance Costs \d\........ $121.............. $10............... $78............... $8.6.
Compliance Costs................ $122.............. $10.2............. $79............... $8.7.
Value of Product Recovery....... $1................ $0.2.............. $1................ $0.1.
Net Benefits.................... $(159) and $(139). $(13) and $(12)... $(116) and $(103). $(12) and $(10).
----------------------------------------------------------------------------------------------------------------
Nonmonetized Benefits: HAP emissions reductions 326 tpy including 14 tpy reduction in chloroprene emissions.
Health effects of reduced exposure to chloroprene and benzene, 1,3-butadiene, vinyl chloride, ethylene
dichloride, chlorine, maleic anhydride, and acrolein.
----------------------------------------------------------------------------------------------------------------
\a\ Values rounded to two significant figures. Totals may not appear to add correctly due to rounding. Short
tons are standard English tons (2,000 pounds).
\b\ Monetized benefits include ozone related health benefits associated with reductions in VOC emissions. The
health benefits are associated with several point estimates and are presented at real discount rates of 3 and
7 percent. The two benefits estimates are separated by the word ``and'' to signify that they are two separate
estimates. The estimates do not represent lower- and upper-bound estimates and should not be summed. Benefits
from annual HAP reductions and VOC reductions outside of the ozone season remain unmonetized and are thus not
reflected in the table.
[[Page 25199]]
\c\ Climate benefits and disbenefits are based on changes (decreases and increases) in CO2, methane and N2O
emissions and are calculated using four different estimates of the social cost of carbon (SC-GHG) (model
average at 2.5 percent, 3 percent, and 5 percent discount rates; 95th percentile at 3 percent discount rate).
For the presentational purposes of this table, we show the benefits and disbenefits associated with the
average SC-GHG at a 3 percent discount rate, but the Agency does not have a single central SC-GHG point
estimate. We emphasize the importance and value of considering the disbenefits calculated using all four SC-
GHG estimates. As discussed in Chapter 4 of the RIA, a consideration of climate disbenefits calculated using
discount rates below 3 percent, including 2 percent and lower, is also warranted when discounting
intergenerational impacts. The use of parentheses surrounding a number denotes a negative value for that
number.
\d\ Net compliance costs are the rulemaking costs minus the value of recovered product. A negative net
compliance costs occurs when the value of the recovered product exceeds the compliance costs.
Table 43--Monetized Benefits, Compliance Costs, Emission Reductions and Net Benefits of the Proposed P&R II
Amendments, 2024 Through 2038
[Dollar estimates in millions of 2021 dollars] \a\
----------------------------------------------------------------------------------------------------------------
3 Percent discount rate 7 Percent discount rate
-------------------------------------------------------------------------------
PV EAV PV EAV
----------------------------------------------------------------------------------------------------------------
Benefits \b\.................... <$0.1............. <$0.1............. <$0.1............. <$0.1.
Net Compliance Costs \c\........ $4................ $0.4.............. $3................ $0.4
Compliance Costs................ $4................ $0.4.............. $3................ $0.4
Value of Product Recovery....... $0................ $0................ $0................ $0
Net Benefits.................... $(4).............. $(0.4)............ $(3).............. $(0.4).
----------------------------------------------------------------------------------------------------------------
Nonmonetized Benefits: HAP emissions reductions 1 tpy. Health effects of reduced exposure to epichlorohydrin.
----------------------------------------------------------------------------------------------------------------
\a\ Values rounded to two significant figures. Totals may not appear to add correctly due to rounding. Short
tons are standard English tons (2,000 pounds).
\b\ Monetized benefits include ozone related health benefits associated with reductions in VOC emissions. The
health benefits are associated with several point estimates and are presented at real discount rates of 3 and
7 percent. The two benefits estimates are separated by the word ``and'' to signify that they are two separate
estimates. The estimates do not represent lower- and upper-bound estimates. Benefits from VOC reductions
outside of the ozone season remain unmonetized and are thus not reflected in the table.
\c\ Net compliance costs are the rulemaking costs minus the value of recovered product. A negative net
compliance costs occurs when the value of the recovered product exceeds the compliance costs.
Table 44--Monetized Benefits, Costs, and Net Benefits of Proposed NSPS Subpart VVb, 2024 Through 2038
[Dollar estimates in millions of 2021 dollars] \a\
----------------------------------------------------------------------------------------------------------------
3 Percent discount rate 7 Percent discount rate
-------------------------------------------------------------------------------
PV EAV PV EAV
----------------------------------------------------------------------------------------------------------------
Benefits \b\.................... $1.2 and $11...... $0.10 and $0.93... $0.85 and $7.5.... $0.09 and $0.82.
Net Compliance Costs \c\........ $11............... $0.9.............. $8................ $0.9.
Compliance Costs................ $13.3............. $1.1.............. $9.7.............. $1.1.
Value of Product Recovery....... $2.3.............. $0.2.............. $1.7.............. $0.2.
Net Benefits.................... $(9.8) and $0..... $(0.8) and $0.03.. $(7.15) and $(0.5) $(0.81) and
$(0.08).
----------------------------------------------------------------------------------------------------------------
\a\ Values rounded to two significant figures. Totals may not appear to add correctly due to rounding. Short
tons are standard English tons (2,000 pounds).
\b\ Monetized benefits include ozone related health benefits associated with reductions in VOC emissions. The
health benefits are associated with several point estimates and are presented at real discount rates of 3 and
7 percent. The two benefits estimates are separated by the word ``and'' to signify that they are two separate
estimates. The estimates do not represent lower- and upper-bound estimates. Benefits from HAP reductions and
VOC reductions outside of the ozone season remain unmonetized and are thus not reflected in the table. There
are no climate benefits and disbenefits for this proposed rule.
\c\ Net compliance costs are the rulemaking costs minus the value of recovered product. A negative net
compliance costs occurs when the value of the recovered product exceeds the compliance costs.
Table 45--Monetized Benefits, Costs, and Net Benefits of Proposed NSPS Subparts IIIa, NNNa, and RRRa, 2024
Through 2038
[Dollar estimates in millions of 2021 dollars] \a\
----------------------------------------------------------------------------------------------------------------
3 Percent discount rate 7 Percent discount rate
-------------------------------------------------------------------------------
PV EAV PV EAV
----------------------------------------------------------------------------------------------------------------
Benefits \b\.................... $4.6 and $41...... $0.39 and $3.5.... $3.2 and $28...... $0.35 and $3.0.
Climate Disbenefits (3 percent) $(6.8)............ $(0.57)........... $(6.8)............ $(0.57).
\c\.
Net Compliance Costs \d\........ $56............... $4.7.............. $40............... $4.4.
Compliance Costs................ $56............... $4.7.............. $40............... $4.4.
Value of Product Recovery....... $0................ $0................ $0................ $0.
Net Benefits.................... $(45) and $(8).... $(3.7) and $(0.6). $(30) and $(5).... $(3.5) and $(0.8).
----------------------------------------------------------------------------------------------------------------
\a\ Values rounded to two significant figures. Totals may not appear to add correctly due to rounding. Short
tons are standard English tons (2,000 pounds).
[[Page 25200]]
\b\ Monetized benefits include ozone related health benefits associated with reductions in VOC emissions. The
health benefits are associated with several point estimates and are presented at real discount rates of 3 and
7 percent. The two benefits estimates are separated by the word ``and'' to signify that they are two separate
estimates. The estimates do not represent lower- and upper-bound estimates. Benefits from HAP reductions and
VOC reductions outside of the ozone season remain unmonetized and are thus not reflected in the table. Climate
disbenefits are estimated at a real discount rate of 3 percent. The unmonetized effects also include
disbenefits resulting from the secondary impact of an increase in CO emissions. Please see Chapter 4 of the
RIA for more discussion of the climate disbenefits.
\c\ Climate disbenefits (inclusive of benefits) are based on changes (increases) in CO2 and N2O emissions and
decreases in methane emissions and are calculated using four different estimates of the social cost of carbon
(SC-GHG) (model average at 2.5 percent, 3 percent, and 5 percent discount rates; 95th percentile at 3 percent
discount rate). For the presentational purposes of this table, we show the disbenefits associated with the
average SC-GHG at a real 3 percent discount rate, but the Agency does not have a single central SC-GHG point
estimate. We emphasize the importance and value of considering the disbenefits calculated using all four SC-
GHG estimates. Please see Table 4-11 of the RIA for the full range of SC-GHG estimates. As discussed in
Chapter 4 of the RIA, a consideration of climate benefits and disbenefits calculated using discount rates
below 3 percent, including 2 percent and lower, is also warranted when discounting intergenerational impacts.
\d\ Net compliance costs are the rulemaking costs minus the value of recovered product. A negative net
compliance costs occurs when the value of the recovered product exceeds the compliance costs. A number in
parentheses denotes a negative value.
Table 46--Cumulative Monetized Benefits, Costs, Emission Reductions and Net Benefits of the Proposed
Rulemakings, 2024 Through 2038
[Dollar estimates in millions of 2021 dollars] \a\
----------------------------------------------------------------------------------------------------------------
3 Percent discount rate 7 Percent discount rate
-------------------------------------------------------------------------------
PV EAV PV EAV
----------------------------------------------------------------------------------------------------------------
Benefits \b\.................... $81 and $730...... $6.8 and $61...... $56 and $490...... $6.1 and $54.
Climate Disbenefits (3 percent) $8.2.............. $0.7.............. $8.2.............. $0.7.
\c\.
Net Compliance Costs \d\........ $1,579............ $132.............. $1,052............ $121.
Compliance Costs................ $1,590............ $133.4............ $1,059.7.......... $122.1.
Value of Product Recovery....... $11............... $1.4.............. $7.7.............. $1.1.
Net Benefits.................... $(1,506) and $(126) and $(71).. $(1,100) and $(110) and $(63).
$(857). $(570).
----------------------------------------------------------------------------------------------------------------
Nonmonetized Benefits: HAP emissions reductions of 6,053 tons of HAP. Health effects of reduced exposure to
ethylene oxide, chloroprene, benzene, 1,3-butadiene, vinyl chloride, ethylene dichloride, chlorine, maleic
anhydride, acrolein, and epichlorohydrin.
----------------------------------------------------------------------------------------------------------------
\a\ Values rounded to two significant figures. Totals may not appear to add correctly due to rounding. Short
tons are standard English tons (2,000 pounds).
\b\ Monetized benefits include ozone related health benefits associated with reductions in VOC emissions. The
health benefits are associated with several point estimates and are presented at real discount rates of 3 and
7 percent. The two benefits estimates are separated by the word ``and'' to signify that they are two separate
estimates. The estimates do not represent lower- and upper-bound estimates. Benefits from HAP reductions and
VOC reductions outside of the ozone season remain unmonetized and are thus not reflected in the table. Climate
disbenefits (inclusive of benefits) are estimated at a real discount rate of 3 percent. The unmonetized
effects also include disbenefits resulting from the secondary impact of an increase in CO emissions. Please
see Chapter 4 of the RIA for more discussion of the climate disbenefits.
\c\ Climate disbenefits are based on changes (increases) in CO2 and N2O emissions and decreases in methane
emissions and are calculated using four different estimates of the social cost of carbon (SC-GHG) (model
average at 2.5 percent, 3 percent, and 5 percent discount rates; 95th percentile at 3 percent discount rate).
For the presentational purposes of this table, we show the disbenefits associated with the average SC-GHG at a
3 percent discount rate, but the Agency does not have a single central SC-GHG point estimate. We emphasize the
importance and value of considering the disbenefits calculated using all four SC-GHG estimates. Please see
Table 4-11 of the RIA for the full range of SC-GHG estimates. As discussed in Chapter 4 of the RIA, a
consideration of climate disbenefits calculated using discount rates below 3 percent, including 2 percent and
lower, is also warranted when discounting intergenerational impacts.
\d\ Net compliance costs are the rulemaking costs minus the value of recovered product. A negative net
compliance costs occurs when the value of the recovered product exceeds the compliance costs.
B. Paperwork Reduction Act (PRA)
1. HON
The information collection activities in this proposed rule have
been submitted for approval to the OMB under the PRA. The ICR document
that the EPA prepared has been assigned EPA ICR number 2753.01. You can
find a copy of the ICR in the docket for this rule, and it is briefly
summarized here.
The EPA is proposing 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 proposing to add requirements pertaining to EtO emissions from
flares, process vents, storage vessels, heat exchange systems,
equipment leaks, and wastewater; and dioxins and furans emissions from
process vents. In addition, the EPA is proposing 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 83,600 hours (per year) to comply with the proposed
amendments in the HON. Burden is defined at 5 CFR 1320.3(b).
Total estimated cost: average annual cost is $70,900,000
(per year) which includes $62,700,000 annualized capital and operations
and maintenance costs, to comply with the proposed amendments in the
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.
Submit your comments on the Agency's need for this information, the
[[Page 25201]]
accuracy of the provided burden estimates, and any suggested methods
for minimizing respondent burden to the EPA using the docket identified
at the beginning of this rule. You may also send your ICR-related
comments to OMB's Office of Information and Regulatory Affairs via
email to [email protected], Attention: Desk Officer for the
EPA. Since OMB is required to make a decision concerning the ICR
between 30 and 60 days after receipt, OMB must receive comments no
later than May 25, 2023. The EPA will respond to any ICR-related
comments in the final rule.
2. P&R I
The information collection activities in this proposed rule have
been submitted for approval to the OMB under the PRA. The ICR document
that the EPA prepared has been assigned EPA ICR number 2410.06. You can
find a copy of the ICR in the docket for this rule, and it is briefly
summarized here.
The EPA is proposing amendments to P&R I 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 proposing to add 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 proposing amendments to P&R I 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 P&R I.
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 proposed
amendments in P&R I. Burden is defined at 5 CFR 1320.3(b).
Total estimated cost: average annual cost is $3,480,000
(per year) which includes $2,680,000 annualized capital and operations
and maintenance costs, to comply with the proposed amendments in P&R I.
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.
Submit your comments on the Agency's need for this information, the
accuracy of the provided burden estimates, and any suggested methods
for minimizing respondent burden to the EPA using the docket identified
at the beginning of this rule. You may also send your ICR-related
comments to OMB's Office of Information and Regulatory Affairs via
email to [email protected], Attention: Desk Officer for the
EPA. Since OMB is required to make a decision concerning the ICR
between 30 and 60 days after receipt, OMB must receive comments no
later than May 25, 2023. The EPA will respond to any ICR-related
comments in the final rule.
3. P&R II
The information collection activities in this proposed rule have
been submitted for approval to the OMB under the PRA. The ICR document
that the EPA prepared has been assigned EPA ICR number 1681.11. You can
find a copy of the ICR in the docket for this rule, and it is briefly
summarized here.
The EPA is proposing amendments to P&R II to add requirements
pertaining to: heat exchange systems, PRDs, dioxins and furans
emissions from process vents, and maintenance vents. In addition, the
EPA is proposing amendments to P&R II 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 P&R II.
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 proposed
amendments in P&R II. 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 proposed amendments in P&R
II.
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.
Submit your comments on the Agency's need for this information, the
accuracy of the provided burden estimates, and any suggested methods
for minimizing respondent burden to the EPA using the docket identified
at the beginning of this rule. You may also send your ICR-related
comments to OMB's Office of Information and Regulatory Affairs via
email to [email protected], Attention: Desk Officer for the
EPA. Since OMB is required to make a decision concerning the ICR
between 30 and 60 days after receipt, OMB must receive comments no
later than May 25, 2023. The EPA will respond to any ICR-related
comments in the 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 proposed rule have
been submitted for approval to the OMB under the PRA. The ICR document
that the EPA prepared has been assigned EPA ICR number 2755.01. You can
find a copy of the ICR in the docket for this rule, and it is briefly
summarized here.
The EPA is proposing in a new NSPS subpart VVb the same
requirements in NSPS subpart VVa plus requiring that
[[Page 25202]]
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. In addition, the EPA is
proposing to remove SSM provisions (the standards apply at all times),
add requirements for electronic reporting of periodic reports, and make
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 $4,540,000
(per year) which includes $4,000,000 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.
Submit your comments on the Agency's need for this information, the
accuracy of the provided burden estimates, and any suggested methods
for minimizing respondent burden to the EPA using the docket identified
at the beginning of this rule. You may also send your ICR-related
comments to OMB's Office of Information and Regulatory Affairs via
email to [email protected], Attention: Desk Officer for the
EPA. Since OMB is required to make a decision concerning the ICR
between 30 and 60 days after receipt, OMB must receive comments no
later than May 25, 2023. The EPA will respond to any ICR-related
comments in the final rule.
6. NSPS Subpart IIIa
The information collection activities in this proposed rule have
been submitted for approval to the OMB under the PRA. The ICR document
that the EPA prepared has been assigned EPA ICR number 2756.01. You can
find a copy of the ICR in the docket for this rule, and it is briefly
summarized here.
The EPA is proposing 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 allow the alternative of maintaining a TRE
index value greater than 1 without the use of a control device);
exclude SSM provisions (and instead, the standards apply at all times);
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 the NSPS. Burden is defined at 5 CFR 1320.3(b).
Total estimated cost: average annual cost is $3,820,000
(per year) which includes $3,800,000 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.
Submit your comments on the Agency's need for this information, the
accuracy of the provided burden estimates, and any suggested methods
for minimizing respondent burden to the EPA using the docket identified
at the beginning of this rule. You may also send your ICR-related
comments to OMB's Office of Information and Regulatory Affairs via
email to [email protected], Attention: Desk Officer for the
EPA. Since OMB is required to make a decision concerning the ICR
between 30 and 60 days after receipt, OMB must receive comments no
later than May 25, 2023. The EPA will respond to any ICR-related
comments in the final rule.
7. NSPS Subpart NNNa
The information collection activities in this proposed rule have
been submitted for approval to the OMB under the PRA. The ICR document
that the EPA prepared has been assigned EPA ICR number 2757.01. You can
find a copy of the ICR in the docket for this rule, and it is briefly
summarized here.
The EPA is proposing 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 allow the alternative of maintaining a TRE
index value greater than 1 without the use of a control device);
exclude SSM provisions (and instead, the standards apply at all times);
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 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 288 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 $4,460,000
(per year) which includes $4,430,000 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.
Submit your comments on the Agency's need for this information, the
accuracy of the provided burden
[[Page 25203]]
estimates, and any suggested methods for minimizing respondent burden
to the EPA using the docket identified at the beginning of this rule.
You may also send your ICR-related comments to OMB's Office of
Information and Regulatory Affairs via email to
[email protected], Attention: Desk Officer for the EPA. Since
OMB is required to make a decision concerning the ICR between 30 and 60
days after receipt, OMB must receive comments no later than May 25,
2023. The EPA will respond to any ICR-related comments in the final
rule.
8. NSPS Subpart RRRa
The information collection activities in this proposed rule have
been submitted for approval to the OMB under the PRA. The ICR document
that the EPA prepared has been assigned EPA ICR number 2759.01. You can
find a copy of the ICR in the docket for this rule, and it is briefly
summarized here.
The EPA is proposing 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 allow the alternative of maintaining a TRE
index value greater than 1 without the use of a control device);
exclude SSM provisions (and instead, the standards apply at all times);
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 the NSPS. Burden is defined at 5 CFR 1320.3(b).
Total estimated cost: average annual cost is $3,820,000
(per year) which includes $3,800,000 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.
Submit your comments on the Agency's need for this information, the
accuracy of the provided burden estimates, and any suggested methods
for minimizing respondent burden to the EPA using the docket identified
at the beginning of this rule. You may also send your ICR-related
comments to OMB's Office of Information and Regulatory Affairs via
email to [email protected], Attention: Desk Officer for the
EPA. Since OMB is required to make a decision concerning the ICR
between 30 and 60 days after receipt, OMB must receive comments no
later than May 25, 2023. The EPA will respond to any ICR-related
comments in the final rule.
C. Regulatory Flexibility Act (RFA)
I certify that each of the proposed 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 proposed amendments to the
HON, the Agency has determined that all small entities affected by this
action, estimated to be 10, 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 ten 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 proposed amendments to P&R I, one small entity is impacted and its
impact is costs less than 0.5 percent of revenues. For the proposed
amendments to P&R II, no small entities are impacted. Details of the
analysis for each proposed rule are presented in the Regulatory Impact
Analysis for this action, which is found in the docket.
D. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. The action imposes no enforceable duty on any state,
local or tribal governments or the private sector.
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
This action is subject to Executive Order 13045 because it is an
economically 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. Accordingly, we have evaluated the
environmental health or safety effects of EtO and chloroprene emissions
on children. The results of this evaluation are contained in sections
II.E and F, III.A and B, and IV.G of this preamble and further
documented in the risk reports, Residual Risk Assessment for the SOCMI
Source Category in Support of the 2023 Risk and Technology Review
Proposed Rule and Residual Risk Assessment for the Polymers & Resins I
Neoprene Production Source Category in Support of the 2023 Risk and
Technology Review Proposed Rule, which are available in the docket.
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 proposed action
would not reduce crude oil supply, fuel production, coal production,
natural gas production, or electricity production. We estimate that
this proposed 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
[[Page 25204]]
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 Regulatory Impact Analysis for this
proposed rulemaking.
I. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR
Part 51
This action involves technical standards. Therefore, the EPA
conducted searches for the HON, P&R I, and P&R II through the Enhanced
National Standards Systems Network (NSSN) 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 reference 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 1A, 2A, 2D, 2F, 2G, 21, 22, 25D, 27, 305, 316, 624, 624.1, 625,
1624 and 1625. Three voluntary consensus standards were identified as
an acceptable alternative to EPA Methods 3B, 18, and 320 for the
purposes of this proposed rule, as follows.
The EPA proposes to use the 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 subpart RRR and NESHAP subpart G) for the
manual procedures only and not the instrumental procedures. 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 American
National Standards Institute (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. 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.
Also, the EPA proposes to use the 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 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. We are proposing that 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 on-site
analysis of extracted, unconditioned, and unsaturated (at the
instrument) gas samples from stationary sources.
In addition, the EPA proposes to use the VCS ASTM D6348-12e1,
``Determination of Gaseous Compounds by Extractive Direct Interface
Fourier Transform (FTIR) Spectroscopy'' as an acceptable alternative to
EPA Method 320 (referenced in NESHAP subparts F, G, and U) with caveats
requiring inclusion of selected annexes to the standard as mandatory.
ASTM D6348-03(2010) was determined to be equivalent to EPA Method 320
with caveats. ASTM D6348-12e1 is a revised version of ASTM D6348-
03(2010) and includes a new section on accepting the results from the
direct measurement of a certified spike gas cylinder, but lacks the
caveats placed on the ASTM D6348-03(2010) version. The VCS ASTM D6348-
12e1 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
D6348-12e, we are proposing the following conditions must be met: (1)
The test plan preparation and implementation in the Annexes to ASTM D
6348-03, Sections A1 through A8 are mandatory; and (2) in ASTM D6348-03
Annex A5 (Analyte Spiking Technique), the percent (%) R must be
determined for each target analyte (Equation A5.5). We are proposing
that 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). We are proposing that 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 two ASTM methods (ASTM D6420-18 and ASTM D6348-12e1) are
available at ASTM International, 1850 M Street NW, Suite 1030,
Washington, DC 20036. 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.
The search identified 13 VCS that were potentially applicable for
this rule in lieu of EPA reference methods. After reviewing the
available standards, EPA determined that 13 candidate VCS (ASTM D3154-
00 (2006), ASTM D3464-96 (2007), ASTM 3796-90 (2004), ISO 10780:1994,
ASME B133.9- 1994 (2001), ANSI/ASME PTC 19-10-198-Part 10, National
Institute of Occupational Safety and Health (NIOSH) Method 2010
``Amines, Aliphatic'', ASTM D6060-96 (2009), ISO 14965:2000(E), EN
12619 (1999), EN 1911-1,2,3 (1998), ASTM D6735-01 (2009), ASTM D4855-97
(2002)) identified for measuring emissions of pollutants or their
surrogates subject to emission standards in the rule would not be
practical due to lack of equivalency, documentation, validation
[[Page 25205]]
data and other important technical and policy considerations.
Additional information for the VCS search and determinations can be
found in the document titled: Voluntary Consensus Standard Results for
National Emission Standards for Hazardous Air Pollutants From the
Synthetic Organic Chemical Manufacturing Industry, which is available
in the docket for this action. The EPA welcomes comments on this aspect
of the proposed rulemaking and, specifically, invites the public to
identify potentially applicable VCS and to explain why such standards
should be used in this regulation.
We are also proposing amendments to 40 CFR part 60, subpart A and
40 CFR part 63, subpart A to address incorporations by reference. We
are proposing that 40 CFR 60.485(g)(5) and 40 CFR 60.485a(g)(5) be
added to 40 CFR 60.17--``Incorporations by Reference'' paragraph
(a)(184) 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
Executive Order 12898 (59 FR 7629, February 16, 1994) directs
federal agencies, to the greatest extent practicable and permitted by
law, to make environmental justice part of their mission by identifying
and addressing, as appropriate, disproportionately high and adverse
human health or environmental effects of their programs, policies, and
activities on minority populations (people of color and/or Indigenous
peoples) and low-income populations.
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 people of color, low-income people, and/or Indigenous
peoples. 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 African American (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 African American (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 proposed regulation, 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 IV.F
for an analysis that characterizes populations living in proximity of
facilities and risks prior to the proposed regulation.
The EPA believes that this action is likely to reduce existing
disproportionate and adverse effects on people of color, low-income
populations and/or Indigenous peoples. This action proposes to
establish standards for EtO emission sources at HON processes and
chloroprene emission sources at neoprene production processes. This
action also proposes amendments to correct and clarify 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, address flare
combustion efficiency, and require fenceline monitoring for pollutants
that drive cancer risks for HON and neoprene production sources. As a
result of these proposed 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 sections III.A and B 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 EJ concerns by
engaging in outreach activities to communities we expect to be impacted
by chemical plants emitting EtO \177\ and by requiring the neoprene
production facility to take a number of actions to reduce and monitor
for fenceline concentrations of chloroprene.\178\ The EPA is also
proposing that HON and P&R I facilities conduct fenceline monitoring
for a number of HAP (i.e., EtO, chloroprene, benzene, 1,3-butadiene,
ethylene dichloride and vinyl chloride) and report these data
electronically to the EPA so that it can be made public and provide
fenceline communities with greater access to information about
potential emissions impacts.
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\177\ https://www.epa.gov/hazardous-air-pollutants-ethylene-oxide/inspector-general-follow-ethylene-oxide-0.
\178\ https://www.epa.gov/la/laplace-st-john-baptist-parish-louisiana.
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The information supporting this Executive Order review is contained
in section IV.F of this preamble, as well as in the technical reports,
Analysis of Demographic Factors for Populations Living Near Hazardous
Organic NESHAP (HON) Facilities, Analysis of Demographic Factors for
Populations Living Near Neoprene Production Facilities, 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.
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.
[FR Doc. 2023-07188 Filed 4-24-23; 8:45 am]
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