[Federal Register Volume 89, Number 66 (Thursday, April 4, 2024)]
[Rules and Regulations]
[Pages 23840-23873]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-05906]



[[Page 23839]]

Vol. 89

Thursday,

No. 66

April 4, 2024

Part IV





Environmental Protection Agency





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40 CFR Part 63





National Emission Standards for Hazardous Air Pollutants: Ethylene 
Production, Miscellaneous Organic Chemical Manufacturing, Organic 
Liquids Distribution (Non-Gasoline), and Petroleum Refineries 
Reconsideration; Final Action; Final Rule

  Federal Register / Vol. 89, No. 66 / Thursday, April 4, 2024 / Rules 
and Regulations  

[[Page 23840]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2022-0787; FRL-9846-02-OAR]
RIN 2060-AV80


National Emission Standards for Hazardous Air Pollutants: 
Ethylene Production, Miscellaneous Organic Chemical Manufacturing, 
Organic Liquids Distribution (Non-Gasoline), and Petroleum Refineries 
Reconsideration

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final action; reconsideration of final rule.

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SUMMARY: On July 6, 2020, the U.S. Environmental Protection Agency (EPA 
or the Agency) finalized the residual risk and technology review (RTR) 
conducted for the Ethylene Production source category, which is part of 
the Generic Maximum Achievable Control Technology Standards National 
Emission Standards for Hazardous Air Pollutants (NESHAP); on July 7, 
2020, the EPA finalized the RTR conducted for the Organic Liquids 
Distribution (Non-Gasoline) NESHAP; and on August 12, 2020, the EPA 
finalized the RTR conducted for the Miscellaneous Organic Chemical 
Manufacturing NESHAP. Amendments to the Petroleum Refinery Sector 
NESHAP were most recently finalized on February 4, 2020. Subsequently, 
the EPA received and granted various petitions for reconsideration on 
these NESHAP for, among other things, the provisions related to the 
work practice standards for pressure relief devices (PRDs), emergency 
flaring, and degassing of floating roof storage vessels. This action 
finalizes proposed amendments to remove the force majeure exemption for 
PRDs and emergency flaring, incorporate clarifications for the 
degassing requirements for floating roof storage vessels, and address 
other corrections and clarifications.

DATES: This final action is effective on April 4, 2024. The 
incorporation by reference of certain material listed in this rule was 
approved by the Director of the Federal Register as of August 12, 2020.

ADDRESSES: The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2022-0787. 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 form. With the exception of such material, publicly available 
docket materials are available either electronically in https://www.regulations.gov/ or in hard copy at the EPA Docket Center, WJC West 
Building, Room Number 3334, 1301 Constitution Avenue NW, Washington, 
DC. The Public Reading Room hours of operation are from 8:30 a.m. to 
4:30 p.m. Eastern Standard Time (EST), Monday through Friday. The 
telephone number for the Public Reading Room is (202) 566-1744, and the 
telephone number for the EPA Docket Center is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: For questions about this final action, 
contact U.S. EPA, Attn: Mr. Michael Cantoni, Sector Policies and 
Programs Division, Mail Drop: E143-01, 109 T.W. Alexander Drive, P.O. 
Box 12055, RTP, North Carolina 27711; telephone number: (919) 541-5593; 
and email address: [email protected].

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

atm-m3/mol atmospheres per mole per cubic meter
ACC American Chemistry Council
AFPM American Fuel and Petrochemical Manufacturers
AMEL alternative means of emissions limitation
API American Petroleum Institute
CAA Clean Air Act
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CEMS continuous emission monitoring systems
CFR Code of Federal Regulations
CRA Congressional Review Act
EMACT Ethylene Production MACT
EPA Environmental Protection Agency
GMACT Generic Maximum Achievable Control Technology
HAP hazardous air pollutant(s)
ICR Information Collection Request
LEL lower explosive limit
MACT maximum achievable control technology
MCPU miscellaneous organic chemical manufacturing process unit
MON Miscellaneous Organic Chemical Manufacturing NESHAP
NAICS North American Industry Classification System
NESHAP national emission standards for hazardous air pollutants
NHV net heating value
NOCS notification of compliance status
NTTAA National Technology Transfer and Advancement Act
OLD Organic Liquids Distribution (Non-Gasoline)
OMB Office of Management and Budget
ppm parts per million
ppmv parts per million by volume
psi pounds per square inch
PRA Paperwork Reduction Act
PRD pressure relief device
RFA Regulatory Flexibility Act
RTR risk and technology review
TCEQ Texas Commission on Environmental Quality
UMRA Unfunded Mandates Reform Act

    Organization of this document. The information in this preamble is 
organized as follows:

I. General Information
    A. What is the source of authority for the reconsideration 
action?
    B. Does this action apply to me?
    C. Where can I get a copy of this document and other related 
information?
II. Background
    A. Ethylene Production
    B. Organic Liquids Distribution (Non-Gasoline)
    C. Miscellaneous Organic Chemical Manufacturing
    D. Petroleum Refineries
III. Final Action
    A. Pressure Relief Devices and Emergency Flaring
    B. Storage Vessel Degassing
    C. Other EMACT Standards Technical Corrections and 
Clarifications
    D. Other OLD NESHAP Technical Corrections and Clarifications
    E. Other MON Technical Corrections and Clarifications
    F. Other Petroleum Refinery MACT 1 Technical Corrections and 
Clarifications
    G. What compliance dates are we finalizing?
IV. Summary of Cost, Environmental, and Economic Impacts
    A. What are the affected facilities?
    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?
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 14094: Modernizing Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That

[[Page 23841]]

Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act (NTTAA) and 
1 CFR Part 51
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations and Executive Order 14096: Revitalizing Our Nation's 
Commitment to Environmental Justice for All
    K. Congressional Review Act (CRA)

I. General Information

A. What is the source of authority for the reconsideration action?

    The statutory authority for this action is provided by sections 112 
and 307(d)(7)(B) of the Clean Air Act (CAA) (42 U.S.C. 7412 and 
7607(d)(7)(B)).

B. Does this action apply to me?

    Table 1 of this preamble lists the NESHAP and associated regulated 
industrial source categories that are the subject of this action. Table 
1 is not intended to be exhaustive, but rather provides a guide for 
readers regarding the entities that this action is likely to affect. 
The final standards will be directly applicable to the affected 
sources. Federal, State, local, and Tribal government entities are not 
affected by this action. Each of the source categories covered by this 
action were 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), 
as well as the National Emission Standards for Hazardous Air 
Pollutants; Revision of Initial List of Categories of Sources and 
Schedule for Standards Under Sections 112(c) and (e) of the Clean Air 
Act Amendments of 1990 (61 FR 28197; June 4, 1996), as presented here.

 Table 1--NESHAP and Industrial Source Categories Affected by This Final
                                 Action
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         Source category                NESHAP          NAICS \1\ code
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Ethylene Production.............  40 CFR part 63,     325110.
                                   subparts XX and
                                   YY.
Organic Liquids Distribution      40 CFR part 63,     3222, 3241, 3251,
 (Non-Gasoline).                   subpart EEEE.       3252, 3259, 3261,
                                                       3361, 3362, 3399,
                                                       4247, 4861. 4869,
                                                       4931, 5622.
Miscellaneous Organic Chemical    40 CFR part 63,     3251, 3252, 3253,
 Manufacturing.                    subpart FFFF.       3254, 3255, 3256,
                                                       and 3259, with
                                                       several
                                                       exceptions.
Petroleum Refineries............  40 CFR part 63,     324110.
                                   subpart CC.
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\1\ North American Industry Classification System (NAICS).

    The Ethylene Production source category includes any chemical 
manufacturing process unit in which ethylene and/or propylene are 
produced by separation from petroleum refining process streams or by 
subjecting hydrocarbons to high temperatures in the presence of steam. 
The ethylene production unit includes the separation of ethylene and/or 
propylene from associated streams such as a C4 product,\1\ 
pyrolysis gasoline, and pyrolysis fuel oil. The ethylene production 
unit does not include the manufacture of Synthetic Organic Chemical 
Manufacturing Industry (SOCMI) chemicals such as the production of 
butadiene from the C4 stream and aromatics from pyrolysis 
gasoline.
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    \1\ The C4 product stream is a hydrocarbon product 
stream from an ethylene production unit consisting of compounds with 
four carbon atoms (i.e., butanes, butenes, butadienes).
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    The Organic Liquids Distribution (Non-Gasoline) source category 
includes, but is not limited to, those activities associated with the 
storage and distribution of organic liquids other than gasoline, at 
sites which serve as distribution points from which organic liquids may 
be obtained for further use and processing. The distribution activities 
include the storage of organic liquids in storage tanks not subject to 
other 40 CFR part 63 standards and transfers into or out of the tanks 
from or to cargo tanks, containers, and pipelines.
    Following the initial source category listings, the Agency combined 
21 of the 174 originally defined source categories, and other organic 
chemical processes which were not included in the original 174 source 
category list, into one source category called the ``Miscellaneous 
Organic Chemical Processes'' source category.\2\ The Agency later 
divided the ``Miscellaneous Organic Chemical Processes'' source 
category into two new source categories called the ``Miscellaneous 
Organic Chemical Manufacturing'' source category and the 
``Miscellaneous Coating Manufacturing'' source category.\3\ The 
Miscellaneous Organic Chemical Manufacturing source category includes 
any facility engaged in the production of benzyltrimethylammonium 
chloride, carbonyl sulfide chelating agents, chlorinated paraffins, 
ethylidene norbornene, explosives, hydrazine, photographic chemicals, 
phthalate plasticizers, rubber chemicals, symmetrical 
tetrachloropyridine, oxybisphenoxarsine/1,3-diisocyanate, alkyd resins, 
polyester resins, polyvinyl alcohol, polyvinyl acetate emulsions, 
polyvinyl butyral, polymerized vinylidene chloride, polymethyl 
methacrylate, maleic anhydride copolymers, or any other organic 
chemical processes not covered by another maximum available control 
technology (MACT) standard. Many of these organic chemical processes 
involve similar process equipment, similar emission points and control 
equipment, and are in many cases co-located with other source 
categories.
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    \2\ 61 FR 57602 (Nov. 7, 1996).
    \3\ 64 FR 63035 (Nov. 18, 1999).
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    The Petroleum Refineries sector includes two source categories. The 
Petroleum Refineries MACT 1 source category includes any facility 
engaged in producing gasoline, naphthas, kerosene, jet fuels, 
distillate fuel oils, residual fuel oils, lubricants, or other products 
from crude oil or unfinished petroleum derivatives. The refinery 
process units in this source category include, but are not limited to, 
thermal cracking, vacuum distillation, crude distillation, 
hydroheating/hydrorefining, isomerization, polymerization, lube oil 
processing, and hydrogen production. The Petroleum Refineries MACT 2--
Catalytic Cracking (Fluid and Other) Units, Catalytic Reforming Units, 
and Sulfur Recovery Units source category includes any facility engaged 
in producing gasoline, naphthas, kerosene, jet fuels, distillate fuel 
oils, residual fuel oils, lubricants, or other products from crude oil 
or unfinished petroleum derivates.

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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 final action will also be available on the internet. Following 
signature by the EPA Administrator, the EPA will post a copy of this 
final action at https://www.epa.gov/stationary-sources-air-pollution/petroleum-refinery-sector-rule-risk-and-technology-review-and-new, 
https://www.epa.gov/stationary-sources-air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-black-hydrogen, https://www.epa.gov/stationary-sources-air-pollution/miscellaneous-organic-chemical-manufacturing-national-emission, and https://www.epa.gov/stationary-sources-air-pollution/organic-liquids-distribution-national-emission-standards-hazardous. Following publication in the Federal Register, the 
EPA will post the Federal Register version and key technical documents 
at these same websites.
    Copies of all comments received on the proposed rulemaking 
(National Emission Standards for Hazardous Air Pollutants: Ethylene 
Production, Miscellaneous Organic Chemical Manufacturing, Organic 
Liquids Distribution (Non-Gasoline), and Petroleum Refineries 
Reconsideration) \4\ are available at the EPA Docket Center Public 
Reading Room. Comments are also available electronically through 
https://www.regulations.gov/ by searching Docket ID No. EPA-HQ-OAR-
2022-0787.
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    \4\ 88 FR 25574 (Apr. 27, 2023).
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    Redline strikeout versions of each rule showing the edits that 
incorporate the changes finalized in this action are presented in the 
documents titled: Final Regulatory Text Edits for Subpart EEEE, Final 
Regulatory Text Edits for Subpart FFFF, Final Regulatory Text Edits for 
Subpart YY, and Final Regulatory Text Edits for Subpart CC, available 
in the docket for this action (Docket ID No. EPA-HQ-OAR-2022-0787).

II. Background

    Following the EPA's finalization of the risk and technology reviews 
for the Ethylene Production (or EMACT), Organic Liquids Distribution 
(Non-Gasoline) (OLD), and Miscellaneous Organic Chemical Manufacturing 
(MON) NESHAP in 2020, the EPA also received petitions for 
reconsideration of these actions. The EPA also received a petition for 
reconsideration of the Petroleum Refinery Sector NESHAP raising some of 
the same issues.
    To address selected issues for which we granted reconsideration and 
to provide other technical corrections, the EPA is finalizing revisions 
to the EMACT standards, OLD NESHAP, MON, and Petroleum Refineries 
NESHAP. The EPA is finalizing revisions to the work practice standards 
for PRDs and emergency flaring related to force majeure provisions in 
the EMACT standards, MON, and Petroleum Refineries NESHAP, and is 
finalizing standards for the degassing of storage vessels in the EMACT 
standards, OLD NESHAP, and MON. The EPA is also adding requirements for 
pressure-assisted flares and mass spectrometers to the Petroleum 
Refineries NESHAP to align this rule with other more recent chemical 
sector rules and eliminate the need to request site-specific 
alternative means of emission limitations (AMELs) for these units. In 
addition, the EPA is finalizing other technical corrections, 
clarifications, and correction of typographical errors in all rules. As 
explained in the proposed rule, the EPA requested comment only on 
specific issues identified in the document and explained that it would 
not address other issues or provisions of these final rules not 
specifically address in the proposed rule.

A. Ethylene Production

    The MACT standards for the Ethylene Production source category 
(herein called the EMACT standards) are contained in the Generic 
Maximum Achievable Control Technology (GMACT) NESHAP, which also 
includes MACT standards for several other source categories. The EMACT 
standards were promulgated on July 12, 2002,\5\ and codified at 40 CFR 
part 63, subparts XX and YY. As promulgated in 2002, and further 
amended,\6\ the EMACT standards regulate hazardous air pollutant (HAP) 
emissions from ethylene production units located at major sources. An 
ethylene production unit is a chemical manufacturing process unit in 
which ethylene and/or propylene are produced by separation from 
petroleum refining process streams or by subjecting hydrocarbons to 
high temperatures in the presence of steam. The EMACT standards define 
the affected source as all storage vessels, ethylene process vents, 
transfer racks, equipment, waste streams, heat exchange systems, and 
ethylene cracking furnaces and associated decoking operations that are 
associated with each ethylene production unit located at a major source 
as defined in CAA section 112(a)(1).
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    \5\ 67 FR 46258 (Jul. 12, 2002).
    \6\ 70 FR 19266 (Apr. 13, 2005); 85 FR 40386 (Jul. 6, 2020).
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    Following promulgation of the EMACT standards in July 2020, the EPA 
received two petitions for reconsideration in September 2020. The EPA 
received a joint petition from the American Chemistry Council (ACC) and 
the American Fuel & Petrochemical Manufacturers (AFPM). The EPA also 
received a petition from Earthjustice (on behalf of RISE St. James, 
Louisiana Bucket Brigade, Louisiana Environmental Action Network, Texas 
Environmental Justice Advocacy Services, Air Alliance Houston, 
Community In-Power & Development Association, Clean Air Council, Center 
for Biological Diversity, Environmental Integrity Project, and Sierra 
Club). Copies of the petitions are provided in the docket for this 
action (see Docket Item No. EPA-HQ-OAR-2022-0787-0005 and EPA-HQ-OAR-
2022-0787-0006). ACC/AFPM's petition requested that the EPA reconsider 
certain aspects of the final action including, among other things, the 
storage vessel degassing provisions, ethylene cracking furnace burner 
repair provisions, and ethylene cracking furnace isolation valve 
inspections. Earthjustice's petition requested that the EPA reconsider 
certain aspects of the final rule including, among other things, the 
force majeure and exemption allowances in the work practice standards 
for PRDs and emergency flaring. ACC/AFPM and Earthjustice also raised 
other issues that are not addressed in this rulemaking.
    On April 19, 2022, the EPA informed the petitioners, ACC/AFPM, and 
Earthjustice that it would grant reconsideration of the provisions 
addressing the work practice standards for PRDs, emergency flaring, and 
degassing of floating roof storage vessels, under CAA section 
307(d)(7)(B). The EPA also informed the petitioners of the continuing 
review of all issues raised in their petitions. A copy of the letter to 
the petitioners is available in the docket for this action (see Docket 
Item No. EPA-HQ-OAR-2022-0787-0022).
    The EPA proposed the reconsideration of the EMACT standards to 
address these issues along with other technical corrections and 
clarifications and requested public comment.\7\
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    \7\ 88 FR 25574 (Apr. 27, 2023).
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    With the exception of out-of-scope comments, this final preamble 
provides summaries and responses to all comments received regarding the 
proposed reconsideration of the EMACT standards. Comments on the 
proposed

[[Page 23843]]

reconsideration of the EMACT standards that we consider out of scope 
for this reconsideration rulemaking include comments on the standards 
for PRDs and emergency flaring that discuss topics other than the force 
majeure provisions.

B. Organic Liquids Distribution (Non-Gasoline)

    The Organic Liquids Distribution (Non-Gasoline) (herein called OLD) 
NESHAP is codified at 40 CFR part 63, subpart EEEE.\8\ Organic liquids 
are any crude oils downstream of the first point of custody transfer 
and any non-crude oil liquid that contains at least 5 percent by weight 
of any combination of the 98 HAP listed in table 1 of 40 CFR part 63, 
subpart EEEE. For the purposes of the OLD NESHAP, as promulgated in 
2004, and further amended,\9\ organic liquids do not include gasoline, 
kerosene (No. 1 distillate oil), diesel (No. 2 distillate oil), 
asphalt, and heavier distillate oil and fuel oil, fuel that is consumed 
or dispensed on the plant site, hazardous waste, wastewater, ballast 
water, or any non-crude liquid with an annual average true vapor 
pressure less than 0.7 kilopascals (0.1 pounds per square inch (psi)). 
Emission sources controlled by the OLD NESHAP are storage tanks, 
transfer operations, transport vehicles while being loaded, and 
equipment leak components (valves, pumps, and sampling connections) 
that have the potential to leak at major sources.
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    \8\ 69 FR 5038 (Feb. 3, 2004).
    \9\ 71 FR 42898 (Jul. 28, 2006); 73 FR 21825 (Apr. 23, 2008); 73 
FR 40977 (Jul. 17, 2008), and 85 FR 40740 (Jul. 7, 2020).
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    The EPA received three petitions for reconsideration for the OLD 
NESHAP in September 2020. The EPA received petitions from Stoel Rives 
LLP (on behalf of Alyeska Pipeline Company), the American Petroleum 
Institute (API) and AFPM, and Earthjustice (on behalf of California 
Communities Against Toxics, Coalition for a Safe Environment, and 
Sierra Club). Copies of the petitions are provided in the docket for 
this rulemaking (see Docket Item No. EPA-HQ-OAR-2022-0787-0015, EPA-HQ-
OAR-2022-0787-0023, and EPA-HQ-OAR-2022-0787-0004). API/AFPM and Stoel 
Rives LLP (on behalf of Alyeska Pipeline Company) requested that the 
EPA reconsider its final action and specifically raised the issue of 
storage vessel degassing. In their respective petitions, API/AFPM, 
Stoel Rives, and Earthjustice also raised other issues that are not 
being addressed in this rulemaking.
    On September 8, 2021, the EPA informed petitioners Stoel Rives, 
API/AFPM, and Earthjustice that it would grant reconsideration on 
certain issues, including the work practice standards for storage 
vessel degassing that apply broadly, under CAA section 307(d)(7)(B). 
Other issues for which EPA granted voluntary reconsideration in the 
September 8, 2021, letter (e.g., work practice standards for venting 
from conservation vents on the Valdez Marine Terminal's crude oil fixed 
roof tanks and fenceline monitoring) are still being reviewed and are 
not part of this action. The EPA also stated in the letter to the 
petitioners that it is continuing to review all issues raised in the 
petitions. A copy of the letter to petitioners is available in the 
docket for this action (see Docket Item No. EPA-HQ-OAR-2022-0787-0016).
    On April 27, 2023, the EPA proposed to reconsider, and requested 
comment on, the OLD NESHAP to address storage vessel degassing along 
with other technical corrections and clarifications.\10\
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    \10\ 88 FR 25574 (Apr. 27, 2023).
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    With the exception of out-of-scope comments, this final preamble 
provides summaries and responses to all comments received regarding the 
proposed reconsideration of the OLD NESHAP. Comments on the proposed 
reconsideration of the OLD NESHAP that we consider out of scope for 
this reconsideration rulemaking include comments on the standards for 
PRDs and emergency flaring that discuss topics other than the force 
majeure provisions and comments on requirements for temporary control 
devices.

C. Miscellaneous Organic Chemical Manufacturing

    The NESHAP for the Miscellaneous Organic Chemical Manufacturing 
source category (herein called MON) is codified at 40 CFR part 63, 
subpart FFFF.\11\ As promulgated in 2003, and further amended,\12\ the 
MON regulates HAP emissions from miscellaneous organic chemical 
manufacturing process units (MCPUs) located at major sources. A 
miscellaneous organic chemical manufacturing process unit (MCPU) 
includes a miscellaneous organic chemical manufacturing process, as 
defined in 40 CFR 63.2550(i), and must meet the following criteria: it 
manufactures any material or family of materials described in 40 CFR 
63.2435(b)(1); it processes, uses, or generates any of the organic HAP 
described in 40 CFR 63.2435(b)(2); and, except for certain process 
vents that are part of a chemical manufacturing process unit, as 
identified in 40 CFR 63.100(j)(4), the MCPU is not an affected source 
or part of an affected source under another subpart of 40 CFR part 63. 
An MCPU also includes any assigned storage tanks and transfer racks; 
equipment in open systems that is used to convey or store water having 
the same concentration and flow characteristics as wastewater; and 
components such as pumps, compressors, agitators, PRDs, sampling 
connection systems, open-ended valves or lines, valves, connectors, and 
instrumentation systems that are used to manufacture any material or 
family of materials described in 40 CFR 63.2435(b)(1). Sources of HAP 
emissions regulated by the MON include the following: process vents, 
storage tanks, transfer racks, equipment leaks, wastewater streams, and 
heat exchange systems.
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    \11\ 68 FR 63852 (Nov. 10, 2003).
    \12\ 70 FR 38562 (July 1, 2005); 71 FR 40316 (Jul. 14, 2006); 
and 85 FR 49084 (Aug. 12, 2020).
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    Following promulgation of the MON in August 2020, the EPA received 
five petitions for reconsideration between October and December 2020. 
The EPA received petitions from the ACC (who submitted two petitions), 
the Texas Commission on Environmental Quality (TCEQ), Huntsman 
Petrochemical, LLC, and Earthjustice (on behalf of RISE St. James, 
Louisiana Bucket Brigade, Louisiana Environmental Action Network, Texas 
Environmental Justice Advocacy Services, Air Alliance Houston, Ohio 
Valley Environmental Coalition, Blue Ridge Environmental Defense 
League, Environmental Justice Health Alliance for Chemical Policy 
Reform, Sierra Club, Environmental Integrity Project, and Union of 
Concerned Scientists). Copies of the petitions are provided in the 
docket for this rulemaking (see Docket Item Nos. EPA-HQ-OAR-2022-0787-
0007, EPA-HQ-OAR-2022-0787-0009, EPA-HQ-OAR-2022-0787-0010, EPA-HQ-OAR-
2022-0787-0027, and EPA-HQ-OAR-2022-0787-0008). ACC's petitions 
requested that the EPA reconsider certain aspects of the final rule 
including, among other things, the storage vessel degassing provisions 
and requirements for ethylene oxide sources. Earthjustice's petition 
requested that the EPA reconsider certain aspects of the final rule 
including, among other things, the force majeure and exemption 
allowances for PRDs and emergency flaring. TCEQ, ACC, and Huntsman 
Petrochemical's petitions requested that the EPA reassess the MON risk 
assessment for issues around ethylene oxide risks. The EPA addressed 
ACC, TCEQ, and Huntsman Petrochemical's

[[Page 23844]]

reconsideration petitions in a separate rulemaking.\13\ Earthjustice 
and ACC also raised other issues that are not being addressed in this 
rulemaking.
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    \13\ 87 FR 77985 (Dec. 21, 2022).
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    On June 17, 2021, the EPA sent a letter to petitioners informing 
them that it is continuing to review all issues raised in the 
petitions. A copy of the letter to petitioners is available in the 
docket for this action (see Docket Item No. EPA-HQ-OAR-2022-0787-0017).
    On April 27, 2023, the EPA proposed the reconsideration of the MON 
to address these issues along with other technical corrections and 
clarifications and requested public comment.\14\
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    \14\ 88 FR 25574 (Apr. 27, 2023).
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    With the exception of out-of-scope comments, this final preamble 
provides summaries and responses to all comments received regarding the 
proposed reconsideration of the MON. Comments on the proposed 
reconsideration of the MON that we consider out of scope for this 
reconsideration rulemaking include:
     Comments on the standards for PRDs and emergency flaring 
that discuss topics other than the force majeure provisions, including 
releases from PRDs in ethylene oxide service and PRD monitoring.
     Comments on surge control vessel or bottoms receiver 
vents.
     Comments on maintenance vent provisions.
     Comments on conservation vent provisions.

D. Petroleum Refineries

    The EPA finalized amendments to the petroleum refinery sector rules 
as the result of an RTR.\15\ These amendments included, among other 
provisions, adding work practice requirements to Petroleum Refinery 
MACT 1 (40 CFR part 63, subpart CC) for PRDs and flares in 40 CFR 
63.648(j) and 63.670(o), respectively. These provisions specifically 
provide requirements for owners and operators to follow in the event of 
an atmospheric PRD release or emergency flaring event including 
performing root cause analysis for each event and implementing 
corrective action(s) in accordance with the rule requirements.
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    \15\ 80 FR 75178 (Dec. 1, 2015).
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    The EPA received three petitions to reconsider the December 2015 
final rule. Two petitions were filed on January 19, 2016, and February 
1, 2016, jointly by API and the AFPM. In response to API/AFPM's January 
19, 2016, petition for reconsideration, the EPA issued a proposal on 
February 9, 2016,\16\ and a final rule on July 13, 2016.\17\ The third 
petition was filed on February 1, 2016, by Earthjustice on behalf of 
Air Alliance Houston, California Communities Against Toxics, the Clean 
Air Council, the Coalition for a Safe Environment, the Community In-
Power & Development Association, the Del Amo Action Committee, the 
Environmental Integrity Project, the Louisiana Bucket Brigade, the 
Sierra Club, the Texas Environmental Justice Advocacy Services, and 
Utah Physicians for a Healthy Environment. In their petition, 
Earthjustice claimed that several aspects of the revisions to the 
Petroleum Refinery MACT 1 were not proposed; therefore, the public was 
precluded from commenting on the altered provisions during the public 
comment period, including, among other provisions, the work practice 
standard for PRDs and emergency flaring.
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    \16\ 81 FR 6814 (Feb. 9, 2016).
    \17\ 81 FR 45232 (Jul. 13, 2016).
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    On June 16, 2016, the EPA informed petitioners it would grant 
reconsideration on issues where petitioners claimed they had not been 
provided an opportunity to comment. Subsequently, the EPA proposed the 
reconsideration of the Petroleum Refinery MACT 1 to address issues for 
which reconsideration was granted in the June 16, 2016, letters.\18\ 
The EPA solicited public comment on five issues in the proposal related 
to the work practice standard for PRDs, the work practice standard for 
emergency flaring events, and the assessment of risk as modified based 
on implementation of these PRD and emergency flaring work practice 
standards. On February 4, 2020, the EPA issued a final action \19\ 
setting forth its decisions on each of the five issues.
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    \18\ 81 FR 71661 (Oct. 18, 2016).
    \19\ 85 FR 6064 (Feb. 4, 2020).
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    On April 6, 2020, Earthjustice submitted a petition for 
reconsideration of the February 2020 final action on behalf of Air 
Alliance Houston, California Communities Against Toxics, Clean Air 
Council, Coalition For A Safe Environment, Community In-Power & 
Development Association, Del Amo Action Committee, Environmental 
Integrity Project, Louisiana Bucket Brigade, Sierra Club, Texas 
Environmental Justice Advocacy Services, and Utah Physicians for a 
Healthy Environment (see Docket Item No. EPA-HQ-OAR-2022-0787-0029). 
The petition for reconsideration requested that the EPA reconsider five 
issues in the February 4, 2020, final rule: (1) The EPA's rationale 
that the PRD standards and emergency flaring standards are continuous; 
(2) the EPA's rationale for the PRD standards under CAA sections 
112(d)(2) and (3); (3) the EPA's rationale for separate work practice 
standards for flares operating above the smokeless capacity; (4) the 
EPA's rationale for risk acceptability and risk determination; and (5) 
the EPA's analysis and rationale in its assessment of acute risk. The 
EPA initially denied the April 6, 2020, petition for reconsideration 
\20\ and provided detailed responses to each of the five issues raised 
in the April 2020 petition in a September 3, 2020, letter, which is 
available in the Petroleum Refinery rulemaking docket (see Docket Item 
No. EPA-HQ-OAR-2010-0682-0999). After further consideration, on April 
19, 2022, EPA informed petitioners that it would undertake 
reconsideration on select provisions related to the work practice 
standard for PRDs and emergency flaring (see Docket Item No. EPA-HQ-
OAR-2022-0787-0003). Specifically, the EPA is reconsidering the 
inclusion of the force majeure allowances in the PRD and emergency 
flaring work practice standard. As noted in our April 19, 2022, letter, 
we may reconsider additional issues in the future.
---------------------------------------------------------------------------

    \20\ 85 FR 67665 (April 6, 2020).
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    On April 27, 2023, the EPA proposed the reconsideration of 
Petroleum Refinery MACT 1 to address the PRD and emergency flaring work 
practice standard along with other technical corrections and 
clarifications and requested public comment.\21\
---------------------------------------------------------------------------

    \21\ 88 FR 25574 (Apr. 27, 2023).
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    With the exception of out-of-scope comments, this final preamble 
provides summaries and responses to all comments received regarding the 
proposed reconsideration of the Petroleum Refinery MACT 1. Comments on 
the proposed reconsideration of the Petroleum Refinery MACT 1 that we 
consider out of scope for this reconsideration rulemaking include 
comments on the standards for PRDs and emergency flaring that discuss 
topics other than the force majeure provisions.

III. Final Action

    In this section of the preamble, the EPA sets forth its final 
decisions on the issues for which reconsideration was granted and on 
which the EPA solicited comment in the April 27, 2023, proposed 
rule.\22\ We also present the Agency's rationale for the decisions. The 
EPA is finalizing revisions to the work practice standards for PRDs and 
emergency flaring related to force majeure provisions in the EMACT

[[Page 23845]]

standards, MON, and Petroleum Refinery MACT 1 and is also finalizing 
clarifications for the degassing of storage vessels in the EMACT 
standards, OLD NESHAP, and MON. In addition, the EPA is finalizing 
requirements for pressure-assisted flares and mass spectrometers in the 
Petroleum Refinery MACT 1 to align this rule with other more recent 
chemical sector rules and to eliminate the need to request site 
specific alternative means of emission limitations (AMELs) for these 
units. Also, the EPA is finalizing other technical corrections, 
clarifications, and correction of typographical errors in all rules. 
The sections below provide a brief summary of each topic as well as 
summaries and responses to the comments received on each topic.
---------------------------------------------------------------------------

    \22\ 88 FR 25574 (Apr. 27, 2023).
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A. Pressure Relief Devices and Emergency Flaring

    Topic summary: Petroleum Refinery MACT 1, EMACT standards, and the 
MON include work practice standards for PRDs and emergency flaring. 
These provisions specifically provide requirements for owners and 
operators to follow in the event of an atmospheric PRD release or 
emergency flaring event including performing root cause analysis for 
each event and implementing corrective action(s) in accordance with the 
rule requirements. The atmospheric PRD release and emergency flaring 
provisions specify the conditions which result in a violation of the 
work practice standards. The owner or operator is required to track the 
number of events by emission unit and root cause. An atmospheric PRD 
release or emergency flaring event for which the root cause is 
determined to be poor maintenance or operator error is a violation of 
the WPS. Two atmospheric PRD releases or two emergency flaring events 
from the same emission unit which are determined to be the result of 
the same root cause in a 3-year period is a violation of the work 
practice standard. Finally, three atmospheric PRD releases or three 
emergency flaring events from the same emission unit regardless of the 
root cause is a violation of the work practice standard (also referred 
to as ``the `three strikes' provisions''). Notably, if the root cause 
is determined to be due to a force majeure event, as defined in 40 CFR 
63.641, 40 CFR 63.1103(e)(2), and 40 CFR 63.2550, it does not count 
towards the criteria for a violation of the WPS. However, in 
reconsidering these provisions, the EPA has recognized that despite the 
term force majeure being carefully defined, the force majeure allowance 
in the work practice standards may present difficulties for determining 
compliance. It may also represent a provision that some facility owners 
or operators may seek to use to avoid incurring violations and pursuing 
potentially disruptive corrective actions. During the root cause 
analysis and corrective action process, owners or operators maintain 
discretion when categorizing and reporting the root cause of 
atmospheric PRD releases and emergency flaring events, thereby placing 
the onus on the EPA to determine whether the definition of force 
majeure was appropriately applied.
    In light of these concerns, we reviewed periodic reports from 
refineries in Texas and Louisiana obtained through the EPA Regional 
Office (Docket ID No. EPA-HQ-OAR-2022-0787-0021 and EPA-HQ-OAR-2022-
0787-0025). Based on the data available, we concluded that the 
frequency of these types of releases is lower than originally expected. 
We also found that by removing the force majeure allowance, the rule is 
strengthened, and compliance becomes easier to assess as it is 
determined purely based on the count of events by emission unit and 
root cause. As such, the EPA proposed to remove the force majeure 
provisions from the PRD and emergency flaring work practice standards. 
See section III.A. of the preamble to the proposed rule for additional 
details.\23\
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    \23\ 88 FR 25580 (Apr. 27, 2023).
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    Comments: A commenter supported the proposed decision to remove 
force majeure provisions from the PRD and emergency flaring work 
practice standards. The commenter stated that the EPA's evaluation of 
refinery periodic reports appropriately concluded the provisions are 
not needed and that compliance with the provisions would become easier 
for facilities and for the EPA to evaluate. The commenter further 
stated the force majeure provisions should be removed because they are 
unlawful and mean that an emission standard does not apply at all times 
for PRDs and flaring. The commenter contended that to ensure that 
standards apply at all times for PRDs, the EPA must specify that any 
uncontrolled release from a PRD is a violation of the standard. For a 
standard to apply at all times for flaring, the commenter asserted that 
the EPA has not shown how a flare will comply with the net heating 
value of the combustion zone limit and achieve 98 percent destruction 
while smoking.
    Other commenters opposed the proposed decision to remove force 
majeure provisions from the PRD and emergency flaring work practice 
standards. Some of these commenters argued that the EPA evaluated too 
narrow of a dataset to identify force majeure events. They stated that 
evaluating data over a longer period is necessary, due to the 
infrequent nature of force majeure events. They also emphasized that 
the review was not representative of all affected source categories, 
because only data from petroleum refineries were analyzed. Furthermore, 
one commenter contended that considering the frequency of events was 
not an adequate basis for removing the provisions.
    Some commenters stated it was not appropriate to remove the force 
majeure provisions because these events are beyond the control of a 
facility and a facility should not be held liable for PRD releases or 
smoking flares during these events. A commenter argued that considering 
the difficulty of enforcing the standard is not a rational basis to 
remove force majeure provisions. The commenter also noted the fact that 
few force majeure events were identified indicates that facilities are 
not abusing the provisions. A commenter stated that removing the force 
majeure provisions could create resource burdens for local authorities 
if there is an increase in violations.
    Response: After consideration of the comments submitted, the EPA is 
finalizing the revisions as proposed and removing the force majeure 
allowance from the criteria for a violation of the work practice 
standards for atmospheric PRD releases and emergency flaring events. 
Commenters indicated that the basis for the EPA's conclusion that the 
force majeure exemption was rarely used was because it only took into 
consideration three years of data. However, this 3-year period is the 
period for which the work practice standards were in effect for 
refineries and thus we believe that this is the best available data 
from which to draw conclusions on the efficacy and necessity of the 
elements of the work practice standards (Standards under CAA section 
112 are to reflect emissions limitations ``for which the Administrator 
has emissions information.''). Although some commenters indicate that 
there were major weather events that could have caused relief events 
from PRDs or flare smoking events, they did not provide any detailed 
information on whether any PRD or flare smoking events actually 
occurred from these weather events.
    In addition, as the EPA has consistently explained, in the event 
that a source fails to comply with the

[[Page 23846]]

applicable CAA section 112 standards, the EPA would determine an 
appropriate response based on, among other things, the good faith 
efforts of the source to minimize emissions during the violative 
periods, including preventative and corrective actions, as well as root 
cause analyses to ascertain and rectify excess emissions. Thus, while 
this action removes the force majeure provisions from the PRD and 
emergency flaring work practice standards, the EPA will continue to 
evaluate violations on a case-by-case basis and determine whether an 
enforcement action is appropriate. If the EPA determines in a 
particular case that enforcement action against a source for violation 
of a standard is warranted, the source can raise any and all defenses 
in that enforcement action and the federal district court will 
determine what, if any, relief is appropriate. The same is true for 
citizen enforcement actions.
    Regarding the comment that the work practice standards do not 
provide continuous standards, we disagree with this comment. We have 
previously addressed this issue and the EPA's position that the force 
majeure provisions do not make the standards non-continuous has not 
changed. We addressed this in the preamble to the proposed rule \24\ 
where we explained that we had previously addressed this in a September 
2020 letter to Earthjustice (Docket Item No. EPA-HQ-OAR-2010-0682-
0999). Components of both the PRD management provisions and emergency 
flaring provisions apply at all times; not all components of the 
standard must apply at all times for the standard to be continuous.
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    \24\ 88 FR 25574, 25580 (Apr. 27, 2023).
---------------------------------------------------------------------------

    Therefore, in this final action for Petroleum Refinery MACT 1, the 
EPA is removing the force majeure allowance from the criteria for a 
violation of the work practice standard for atmospheric PRD releases 
and emergency flaring events in 40 CFR 63.648(j)(3) and 63.670(o)(7). 
We are also amending the reporting requirements for the event-specific 
work practice standard data in 40 CFR 63.655(g)(10)(iv) and (11)(iv) to 
require these data to be reported electronically through the EPA's 
Central Data Exchange (CDX) using the Compliance and Emissions Data 
Reporting Interface (CEDRI). As further discussed in section III.G. of 
this preamble, we are finalizing that the removal of the force majeure 
provisions is effective 60 days after the effective date of the final 
rule.
    For flares, the EMACT standards and MON cross reference the 
petroleum refinery flare provisions at 40 CFR 63.670. Therefore, the 
revisions to 40 CFR 63.670(o)(7) for emergency flaring events are 
incorporated into the requirements for these regulations.
    The EPA is also revising the EMACT standards and the MON consistent 
with our proposal. We are removing the force majeure allowance from the 
criteria for a violation of the work practice standard for atmospheric 
PRD releases in 40 CFR 63.1107(h)(3) and 63.2480(e)(3) going forward. 
However, we are not removing the term force majeure from the list of 
defined terms in 40 CFR 63.1103(e)(2) and 63.2550. As further discussed 
in section III.G. of this preamble, we are finalizing that the removal 
of the force majeure provisions is effective 60 days after the 
effective date of the final rule. Lastly, the EPA is finalizing new 
reporting requirements for the EMACT standards at 40 CFR 
63.1110(a)(10)(iii) to require electronic reporting, through the CDX 
using CEDRI, of the event-specific work practice standard data in 40 
CFR 63.1110(e)(4)(iv) and 63.1110(e)(8)(iii). We note that the MON 
already has a more general compliance report template for electronic 
reporting, see 40 CFR 63.2520(e), which will automatically incorporate 
electronic reporting of the event-specific work practice standard data.

B. Storage Vessel Degassing

    Topic summary: The EMACT standards, OLD NESHAP, and MON currently 
include a work practice standard for storage vessel degassing to 
control emissions from shutdown operations (see 40 CFR 63.1103(e)(10), 
40 CFR 63.2346(a)(6), and 40 CFR 63.2470(f), respectively). An 
opportunity to comment on the storage vessel degassing provisions was 
not previously provided because, based on comments received for all 
three rules, the provisions were included in the final 2020 rules but 
not in the rules proposed in 2019. Therefore, the EPA re-proposed in 
2023 what was finalized for each rule in 2020. The EPA also proposed 
additional revisions based on petitioners' arguments to address 
degassing of floating roof storage vessels. The requirements, as 
finalized in the 2020 rules, 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 lower explosive limit (LEL)) and 
all standing liquid has been removed from the vessel to the extent 
practicable. The requirements are applicable to all storage vessels 
(regardless of roof type) that are subject to control requirements in 
each of the rules. We based the degassing standard on Texas permit 
conditions, which represented the MACT floor.\25\ Specifically, permit 
condition 6 (applicable to floating roof storage vessels) and permit 
condition 7 (applicable to fixed roof storage vessels) formed the basis 
of the storage vessel degassing standard.
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    \25\ Texas Permit Conditions are available at: https://www.tceq.texas.gov/assets/public/permitting/air/Guidance/NewSourceReview/mss/chem-mssdraftconditions.pdf.
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    The petitioners stated that while they did identify the Texas 
permit conditions as a reference in their comments to the 2019 proposed 
rules, certain key information was not incorporated into the final 2020 
EMACT standards, OLD NESHAP, and MON for the degassing of floating roof 
storage vessels. Additionally, the petitioners argued that they did not 
request additional work practices for floating roof storage vessels for 
which owners and operators already elect to comply with the floating 
roof storage vessels requirements in 40 CFR part 63, subpart WW 
because, even with the removal of the shutdown exemption, the 
petitioners contended that it is still possible to comply with the 
subpart WW provisions.
    The EPA disagreed with the petitioners' claims that a separate 
standard for floating roof storage vessel degassing is not needed due 
to the removal of the shutdown exemption. Rather, we determined that we 
must set a storage vessel degassing standard that applies to storage 
vessels under CAA section 112. We also determined that storage vessel 
degassing is a unique shutdown activity with operations and emissions 
that are completely different from normal storage vessel operations, 
and 40 CFR part 63, subpart WW does not address degassing emissions 
from floating roof storage vessels.
    Because the EPA determined that a standard is necessary for 
degassing of all storage vessels (regardless of roof type), the EPA 
reviewed the Texas permit conditions again to determine if revisions to 
the degassing standard for floating roof storage vessels in the EMACT 
standards, OLD NESHAP, and MON are appropriate. Based upon this review, 
we proposed and are now finalizing 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 operators must not actively purge the storage vessel 
while connections are made. See section III.B. of the preamble to the 
proposed rule for additional details on the storage vessel degassing 
revisions.\26\
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    \26\ 88 FR 25581 (Apr. 27, 2023).

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[[Page 23847]]

    Comments: Several commenters supported the storage vessel degassing 
requirements in the 2023 proposal, including having a separate 
requirement for floating roof storage vessels. However, some commenters 
requested clarification on certain aspects of the rule text. A 
commenter requested clarification on whether the phrase ``must not be 
actively degassed'' (from the rule text) and ``not actively purge'' 
(from the preamble) have the same meaning for floating roof storage 
vessels. The commenter also requested confirmation that breathing 
emissions following a floating roof landing and before commencing 
degassing operations are not a deviation of the standard. A commenter 
stated that not providing a timeframe for degassing creates ambiguity 
and encouraged the EPA to use the same 24-hour window as the Texas 
permit conditions for consistency. Another commenter recommended the 
EPA incorporate a requirement based on the maintenance vent standard, 
which would allow active purging if the pressure in the storage vessel 
is 2 pounds per square inch gauge or less. A commenter recommended that 
the EPA incorporate additional recordkeeping and reporting requirements 
for storage vessel degassing, such as recording and reporting 
information from the vapor space concentration measurements. A 
commenter also requested the EPA further define degassing.
    Response: After consideration of the comments submitted, we are 
finalizing the storage vessel degassing requirements as proposed, 
including the separate requirement for floating roof storage vessels. 
We do confirm that the phrase ``must not be actively degassed'' (from 
the rule text) and ``not actively purge'' (from the preamble) have the 
same meaning for purposes of the floating roof storage vessel degassing 
provisions. We are also aware that the Texas permit condition 6.B 
provides a 24-hour window to start controlled degassing after the 
floating roof storage vessel has been drained, and that the storage 
vessel may be opened during this period only to set up for degassing 
and cleaning. However, we determined at proposal that the 24-hour 
window stipulates how long a floating roof storage vessel can be landed 
before it needs to be filled again or degassed, but it does not have a 
direct bearing on the underlying control standard for degassing 
operations. As such, we are not revising the final rule to incorporate 
the 24-hour window into the storage vessel degassing standard.
    We agree with the commenter that emissions as a result of vapor 
space expansion (i.e., breathing emissions) following landing of a 
floating roof and prior to commencing degassing operations do not 
constitute a bypass or deviation of the standards. We note that this 
work practice standard for storage vessel degassing applies ``during 
storage vessel shutdown operations (i.e., emptying and degassing of a 
storage vessel).''
    We also do not agree that incorporating a requirement similar to 
the maintenance vent standard is appropriate for storage vessel 
degassing. The intent of the standard is to control degassing emissions 
to the level of the MACT floor, which in this case is the use of 
controls to minimize emissions until the vapor space concentration 
reaches 10 percent of the LEL.
    We do not believe that additional clarity on the definition of 
degassing is warranted as this process is well understood. Storage 
vessel degassing has always been in the rules as part of the definition 
of ``Shutdown'' (i.e., Shutdown also applies to emptying and degassing 
storage vessels). In addition, there have been many commenters on each 
of the rules over the past four years providing feedback regarding 
storage vessel degassing; during this time no clarifications regarding 
the definition of degassing were needed.
    We are finalizing clarifications to the storage vessel degassing 
standards for the EMACT standards at 40 CFR 63.1103(e)(10), the OLD 
NESHAP at 40 CFR 63.2346(a)(6), and the MON at 40 CFR 63.2470(f).
    We also want to clarify that the overlap provisions in the MON and 
OLD NESHAP for storage vessels do not apply with respect to 
demonstrating compliance with the storage vessel degassing 
standards.\27\ While these overlap provisions (e.g., 40 CFR part 60, 
subpart Kb; 40 CFR part 61, subpart Y) do include storage vessel 
standards that facilities subject to the MON and OLD NESHAP may comply 
with for storage vessels during normal operation, they do not include 
an equivalent alternative standard to the storage vessel degassing 
standards that were finalized in 2020 and that are being clarified in 
this final action. As such, facilities subject to the MON and OLD 
NESHAP must always comply with the storage vessel degassing standards 
included therein even if complying with these overlap provisions.
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    \27\ The EMACT standards require owners or operators to comply 
specifically with the EMACT standards where overlap may exist for 
various storage vessel control requirements (see 40 CFR 
63.1100(g)(1)); thus, it is not necessary to clarify that the 
storage vessel degassing standards always apply in this NESHAP.
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C. Other EMACT Standards Technical Corrections and Clarifications

    The EPA is finalizing additional revisions for the EMACT standards 
that address other technical corrections and clarifications and correct 
typographical errors. We received comments on some of the revisions 
that were proposed for the EMACT standards. In this section, we provide 
comment summaries and responses for the EMACT standards topics where 
comments were received. We also include revisions to the EMACT 
standards that were not proposed but for which commenters provided 
technical clarifications to the rule and the EPA is finalizing. Table 2 
of this preamble shows the revisions to the EMACT standards for which 
no comments were received, and that the EPA is finalizing as proposed. 
Although we briefly summarize these items below, refer to section 
III.C.1. of the preamble to the proposed rule for additional 
details.\28\
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    \28\ 88 FR 25582 (Apr. 27, 2023).
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    Topic summary, delay of burner repair provisions (40 CFR 
63.1103(e)(7)(i)): A petitioner argued that requiring an ethylene 
cracking furnace to implement the delay of burner repair provisions 
finalized in the 2020 final rule is impracticable and is inconsistent 
with what the best performers are doing. The petitioner stated that a 
significant amount of preparation is needed to shutdown an ethylene 
cracking furnace and that no source can comply with the delay of burner 
repair provisions as written. Accordingly, where a burner cannot be 
repaired without an ethylene cracking furnace shutdown, owners or 
operators would have to decoke their ethylene cracking furnaces 
immediately (i.e., within 1 day of identifying flame impingement), 
leading to more decoking events and subsequently more emissions from 
the decoking of ethylene cracking furnaces.
    An opportunity to comment on the delay of burner repair provisions 
was not previously provided because the provisions were included in the 
final 2020 rule but not in the 2019 proposed rule. Therefore, the EPA 
re-proposed at 40 CFR 63.1103(e)(7)(i) what was finalized along with 
the following revisions for delay of burner repair.
    The EPA proposed to remove the requirement that the owner or 
operator may only delay burner repair beyond 1 calendar day if a 
shutdown for repair would cause greater emissions than the potential 
emissions from delaying repair. We agreed that this requirement

[[Page 23848]]

if left in place would lead to more decoking events and more emissions 
from decoking of ethylene cracking furnaces. Instead of evaluating 
emissions to determine whether delay of repair is allowed, the EPA 
proposed that delay of repair beyond 1 calendar day is allowed if the 
repair cannot be completed during normal operations, the burner cannot 
be shutdown without significantly impacting the furnace heat 
distribution and firing rate, and action is taken to reduce flame 
impingement as much as possible during continued operation. We also 
maintained that if a delay of repair is required to fully resolve 
burner flame impingement, repair must be completed following the next 
planned decoking operation (and before returning the ethylene cracking 
furnace back to normal operation) or during the next ethylene cracking 
furnace complete shutdown (when the ethylene cracking furnace firebox 
is taken completely offline), whichever is earlier.
    Comments: A few commenters supported the proposed revision to the 
ethylene cracking furnace delay of burner repair requirements. They 
indicated that the proposed language provided needed flexibility. 
However, some of the commenters recommended additional revisions to the 
language to add specificity regarding when burner repair is allowed. 
Specifically, the commenters asked for an allowance to delay repairs 
until the next planned shutdown if a complete furnace shutdown is 
required to complete the repair.
    Response: We disagree with the commenters that additional 
allowances for burner repair are warranted and are finalizing the 
revisions as proposed. We proposed the revisions to the delay of repair 
language to provide flexibility and acknowledge the industry's general 
practice for burner inspection and repair. However, allowing facilities 
to protract burner repair to a further point in time, which may be 
years in the future for the next ethylene cracking furnace complete 
shutdown, goes against the purpose of the burner inspection and repair 
provisions which is to stop flame impingement and minimize decoking 
emissions. Additionally, the decoking of ethylene cracking furnaces has 
always been included in the definition of Shutdown in the regulatory 
text of the EMACT standards and has always been considered a shutdown 
operation. The EPA is finalizing the delay of burner repair provisions 
as proposed and owners or operators must repair the burner following 
the next decoking event or complete shutdown, whichever is earlier.
    Topic summary, isolation valve inspection and repair (40 CFR 
63.1103(e)(8)(i)): A petitioner requested that the EPA revise the 
requirement to rectify poor isolation prior to continuing decoking 
operations. The petitioner argued that certain isolation valve repairs 
must be completed after the ethylene cracking furnace is shutdown, 
which consequently requires decoking the ethylene cracking furnace. The 
petitioner said that if a furnace is not decoked prior to shutdown, 
damage can occur to the furnace tubes and could pose a safety issue. In 
addition, the petitioner noted that some isolation valves serve gas 
streams from multiple ethylene cracking furnaces, and there may be 
instances when all furnaces would need to be decoked and shutdown to 
properly rectify the isolation valve issue. The petitioner argued that 
allowing for some flexibility is necessary for facilities to operate 
properly and to avoid damaging equipment.
    We agreed with the petitioner and proposed language at 40 CFR 
63.1103(e)(8)(i) to allow facilities to wait and rectify isolation 
valve issues after a decoking operation, provided that the owner or 
operator can reasonably demonstrate that damage to the radiant tube(s) 
or ethylene cracking furnace would occur if the repair was attempted 
prior to completing a decoking operation and/or prior to the ethylene 
cracking furnace being shutdown.
    Comments: Some commenters supported the proposed revision to the 
ethylene cracking furnace isolation valve inspection and repair 
requirements. They indicated that the proposed language was consistent 
with industry practices. The commenters also recommended additional 
revisions to emphasize that the company must be able to make the 
determination regarding whether to delay repair if the radiant tubing 
or ethylene cracking furnace could be damaged.
    Response: The EPA acknowledges the commenters' support and is 
revising the proposed language in response to the comments. We agree 
that the owner or operator does not need to directly demonstrate to the 
regulating authority that damage would occur to the radiant tubes or 
ethylene cracking furnace before using the allowance to delay repair. 
We are clarifying in 40 CFR 63.1103(e)(8)(i) that the owner or operator 
can make the determination that damage could occur in order to avail 
themselves of this delay of repair allowance.
    Topic summary, removal of electronic reporting requirements (40 CFR 
63.1100(b), 63.1103(e)(4)(iii), and 63.1110(a)(10)(i), (ii), (iii), and 
(iv)): Instructions for submitting reports electronically through 
CEDRI, including instructions for submitting CBI and asserting a claim 
of EPA system outage or force majeure, were recently added to 40 CFR 
63.9(k); \29\ therefore, text related to these requirements was no 
longer necessary in the EMACT standards. As such, we removed 
duplication and pointed directly to 40 CFR 63.9(k) when required to 
submit certain reports to CEDRI.
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    \29\ 85 FR 73885 (Nov. 19, 2020).
---------------------------------------------------------------------------

    Comment: A commenter agreed with the revisions to point to 40 CFR 
63.9(k) directly, but also stated that an additional reference to this 
citation is warranted in 40 CFR 63.1100(b).
    Response: We agree with the commenter and are referencing 40 CFR 
63.9(k) in the last sentence of 40 CFR 63.1100(b). We are also 
finalizing the edits at 40 CFR 63.1103(e)(4)(iii) and 
63.1110(a)(10)(i), (ii), (iii), and (iv), as proposed.
    Topic summary, LEL clarification (40 CFR 63.1103(e)(5), 
63.1103(e)(10), 63.1109(f), 63.1110(e)(5)): These provisions reference 
the term ``LEL'' for the purposes of determining compliance. We did not 
propose revisions for this term, but commenters provided feedback 
stating that it was being misused.
    Comments: Commenters stated that we were misusing the term LEL in 
certain rule provisions for maintenance vents and storage vessel 
degassing (e.g., 40 CFR 63.1103(e)(5), 40 CFR 63.1103(e)(10)). 
Commenters stated the LEL was a fixed physical property of a vapor 
mixture and thus, is neither changed nor measured. According to 
commenters, LEL refers to a specific concentration value for a 
particular mixture. For example, when opening a maintenance vent, 
commenters elaborated that you measure the concentration of the vapor 
and then you can compare that concentration to the LEL. The commenter 
thought the rule text incorrectly implied that you measured the LEL of 
the vapor. The commenters requested that the EPA clarify that the 
concentration of the vapors in equipment for maintenance vents (and the 
vapor space concentration for storage vessel degassing) must be less 
than 10 percent of the LEL and that facilities are to measure the 
concentration, not the LEL.
    Response: We agree with commenters that the rule text referring to 
the LEL was used incorrectly for certain

[[Page 23849]]

maintenance vent and storage vessel degassing provisions and that the 
LEL cannot be changed for a vapor. We are revising the rule text to 
make clear that facilities measure the vapor concentration and then 
compare that concentration value to the LEL of the vapor to determine 
if the concentration is less than 10 percent of the LEL.

  Table 2--Summary of Revisions to 40 CFR Part 63, Subpart YY for Which
                       the EPA Received No Comment
------------------------------------------------------------------------
           Provision              Issue summary        Final revision
------------------------------------------------------------------------
40 CFR 63.1110(e)(4)(iii).....  Provision          The EPA is replacing
                                 contains a         ``Sec.
                                 typographical      63.1109(e)(7)'' with
                                 error.             ``Sec.
                                                    63.1109(e)(6)'' to
                                                    correct the
                                                    typographical error.
40 CFR 63.1102(c)(11),          Provisions         The EPA is replacing
 (d)(2)(ii), and (e)(2)(iii).    contain a          ``Sec.
                                 typographical      63.1108(a)(4)(i)''
                                 error.             with ``Sec.
                                                    63.1108(a)(4)'' to
                                                    correct a
                                                    typographical error
                                                    that we made while
                                                    removing startup,
                                                    shutdown, and
                                                    malfunction
                                                    exemptions.
------------------------------------------------------------------------

D. Other OLD NESHAP Technical Corrections and Clarifications

    There are additional revisions that we are finalizing for the OLD 
NESHAP to address other technical corrections and clarifications and to 
correct typographical errors. We did not receive comments on all of the 
revisions that were proposed for the OLD NESHAP. Table 3 of this 
preamble shows the revisions to the OLD NESHAP for which no comments 
were received and the EPA is finalizing as proposed. Table 4 of this 
preamble shows revisions to the OLD NESHAP which were not proposed but 
where commenters provided technical clarifications to the rule, which 
the EPA is finalizing. Refer to section III.C.2. of the preamble to the 
proposed rule for additional details.\30\
---------------------------------------------------------------------------

    \30\ 88 FR 25584 (Apr. 27, 2023).

 Table 3--Summary of Revisions to 40 CFR Part 63, Subpart EEEE for Which
                       the EPA Received No Comment
------------------------------------------------------------------------
          Provision               Issue summary        Final revision
------------------------------------------------------------------------
40 CFR 63.2346(a)(6)........  Provision contains a  The EPA is replacing
                               typographical error.  ``items 3 through 6
                                                     of table 2 to this
                                                     subpart'' with
                                                     ``items 2 through 6
                                                     of table 2 to this
                                                     subpart'' to
                                                     correct the
                                                     typographical
                                                     error.
40 CFR 63.2346(e)...........  Provision contains a  The EPA is replacing
                               typographical error.  ``storage vessels''
                                                     with ``storage
                                                     tanks'' to correct
                                                     the typographical
                                                     error.
40 CFR 63.2378(e)(3)........  Provision needing     The EPA is adding
                               technical             the word
                               clarifications.       ``planned'' in
                                                     front of ``routine
                                                     maintenance'' in
                                                     the last sentence
                                                     of the provision in
                                                     order to further
                                                     clarify the
                                                     provision only
                                                     applies to periods
                                                     of planned routine
                                                     maintenance. We are
                                                     also replacing
                                                     ``storage vessel''
                                                     with ``storage
                                                     tank'' in the last
                                                     sentence of the
                                                     provision to
                                                     correct a
                                                     typographical
                                                     error.
40 CFR 63.2378(e)(4)........  Provision needing     To create
                               technical             consistency in the
                               clarifications.       time period during
                                                     which the bypass
                                                     provision applies
                                                     (i.e., the level of
                                                     material in the
                                                     storage vessel must
                                                     not be increased
                                                     during the same
                                                     time period that
                                                     breathing loss
                                                     emissions bypass
                                                     the fuel gas system
                                                     or process), we are
                                                     deleting ``to
                                                     perform routine
                                                     maintenance'' from
                                                     the last sentence
                                                     of 40 CFR
                                                     63.2378(e)(4). We
                                                     are also replacing
                                                     ``storage vessel''
                                                     with ``storage
                                                     tank'' in the last
                                                     sentence of the
                                                     provision to
                                                     correct a
                                                     typographical
                                                     error.
40 CFR 63.2382(d)(3);         Provisions needing    The EPA is removing
 63.2386(f), (g), (h), (i),    technical             duplication and
 and (j); and 63.2406.         clarifications or     pointing directly
                               removal.              to 40 CFR 63.9(k)
                                                     when required to
                                                     submit certain
                                                     reports to CEDRI.
                                                     Specifically,
                                                     instructions for
                                                     submitting reports
                                                     electronically
                                                     through CEDRI,
                                                     including
                                                     instructions for
                                                     submitting CBI and
                                                     asserting a claim
                                                     of EPA system
                                                     outage or force
                                                     majeure, were
                                                     recently added to
                                                     40 CFR 63.9(k) (85
                                                     FR 73885; November
                                                     19, 2020);
                                                     therefore, text
                                                     related to these
                                                     requirements was no
                                                     longer necessary in
                                                     the OLD NESHAP.
------------------------------------------------------------------------


[[Page 23850]]


 Table 4--Summary of Revisions to 40 CFR Part 63, Subpart EEEE That Were
      Not Proposed But Are Being Finalized Based on Commenter Input
------------------------------------------------------------------------
          Provision               Issue summary        Final revision
------------------------------------------------------------------------
40 CFR 63.2346(a)(6)........  In comments on the    While commenters did
                               EMACT standards,      not specifically
                               MON, and Petroleum    point out revisions
                               Refinery MACT 1,      to the OLD NESHAP,
                               commenters stated     we are finalizing
                               that we were          revisions to 40 CFR
                               misusing the term     63.2346(a)(6) for
                               LEL in certain rule   consistency.
                               language provisions   Specifically, we
                               for maintenance       are clarifying that
                               vents and storage     the owner or
                               vessel degassing.     operator must
                               See the comment       determine the
                               summary and           concentration of
                               response in section   the vapor space as
                               III.C. of this        opposed to
                               preamble for          determining the LEL
                               additional details.   of the vapor space.
Table 12 to Subpart EEEE of   Provisions needing    40 CFR 63.7(a)(4) is
 Part 63.                      technical             not cited in the
                               clarifications.       general provisions
                                                     applicability
                                                     table. We are
                                                     referencing 40 CFR
                                                     63.7(a)(4) in this
                                                     table and stating
                                                     it applies to the
                                                     OLD NESHAP.
------------------------------------------------------------------------

E. Other MON Technical Corrections and Clarifications

    This section of the preamble presents revisions we are finalizing 
to the MON heat exchange system requirements along with additional 
revisions that we are finalizing for the MON to address other technical 
corrections and clarifications and to correct typographical errors. We 
did not receive comments on some of the revisions that were proposed 
for the MON. In this section, we provide comment summaries and 
responses for the MON topics where comments were received. We also 
include revisions to the MON which were not proposed but where 
commenters provided technical clarifications to the rule, which the EPA 
is finalizing. Following this, table 5 of this preamble shows the 
revisions to the MON for which no comments were received, and the EPA 
is finalizing as proposed. We briefly summarize these items below; see 
section III.C.3. of the preamble to the proposed rule for additional 
details.\31\
---------------------------------------------------------------------------

    \31\ 88 FR 25584 (Apr. 27, 2023).
---------------------------------------------------------------------------

    Topic summary, leak monitoring requirements for heat exchange 
systems with soluble HAP (40 CFR 63.2490(e)): 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 (see Docket Item No. EPA-HQ-OAR-2022-0787-0028). Eastman 
requested that the previous water sampling requirements for heat 
exchange system leaks provided in the MON, which ultimately references 
40 CFR 63.104(b) (i.e., use of any EPA-approved method listed in 40 CFR 
part 136 as long as the method is sensitive to concentrations as low as 
10 parts per million (ppm) and the same method is used for both 
entrance and exit samples), be allowed for cooling water containing 
certain soluble HAP in lieu of using the Modified El Paso Method. 
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. 
Based upon a review of the information provided by Eastman, we proposed 
that water sampling of heat exchange systems may be used but only if 99 
percent by weight or more of all the organic compounds that could 
potentially leak in the cooling water have a Henry's Law Constant less 
than a certain threshold (i.e., 5.0E-6 atmospheres per mole per cubic 
meter (atm-m\3\/mol) at 25[deg] Celsius). See section III.C.3. of the 
preamble to the proposed rule for additional details.\32\
---------------------------------------------------------------------------

    \32\ 88 FR 25584 (Apr. 27, 2023).
---------------------------------------------------------------------------

    Comments: Some commenters supported the proposed revisions to allow 
for water sampling of heat exchange systems, instead of the Modified El 
Paso Method, in limited instances. However, each of the commenters also 
argued that the EPA must revise the proposed language to add 
specificity regarding the compounds for which the water sampling 
alternative could be used. The commenters stated that the requirement 
should only apply to heat exchange systems with 99 percent by weight or 
more of organic HAP compounds that meet certain thresholds instead of 
just 99 percent by weight or more of organic compounds that meet 
certain thresholds. The commenters contended that because the rule 
serves to identify leaks of HAP, specifying that the threshold applies 
only to organic HAP is necessary. The commenters were concerned the 
proposed revisions could lead to expenditures fixing leaks that do not 
contain HAP. A commenter also requested the EPA clarify whether small 
heat exchange systems with a cooling water flow rate of 10 gallons per 
minute or less are required to use the Modified El Paso Method.
    Response: After considering the comments submitted, the EPA is 
finalizing the monitoring revisions as proposed to allow for water 
sampling of heat exchange systems in limited instances. We disagree 
with the commenters' request to revise the language to specify ``HAP'' 
compounds for the 99 percent by weight requirement. The proposed 
revisions do not impact what heat exchangers are subject to monitoring; 
rather they help determine what type of monitoring is allowed (i.e., 
Modified El Paso Method or water sampling), and the existing language 
already includes specificity regarding HAP compounds. The definition of 
heat exchange system states that the heat exchange system must be in 
organic HAP service (i.e., contain at least 5 percent by weight of 
total organic HAP) in order to be subject to the heat exchange system 
monitoring requirements. Additionally, 40 CFR 63.104(b) is clear that 
owners and operators must monitor for ``the presence of one or more 
organic hazardous air pollutants or other representative substances 
whose presence in cooling water indicates a leak.'' The introductory 
text of 40 CFR 63.2490(e), which says: ``you may monitor the cooling 
water for leaks according to the requirements in Sec.  63.104(b) in 
lieu of using the Modified El Paso Method,'' is also only intended to 
specify what type of monitoring is required.
    Regarding small heat exchange systems with a cooling water flow 
rate of 10 gallons per minute or less, we believe that further 
clarification to the rule is not needed. The 10 gallons per

[[Page 23851]]

minute threshold provided in 40 CFR 63.2490(d) only applies to the 
Modified El Paso Method monitoring requirements in 40 CFR 63.2490(d). 
As such, heat exchange systems with a cooling water flow rate of 10 
gallons per minute or less are still subject to the requirements of 40 
CFR 63.104, as they have been historically, and must continue complying 
as they always have.
    In summary, the EPA is finalizing at 40 CFR 63.2490(e) that the 
leak monitoring requirements for heat exchange systems at 40 CFR 
63.104(b) may be used in limited instances (i.e., 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) 
instead of using the Modified El Paso Method to monitor for leaks. 
While we are finalizing that the leak monitoring and leak definition 
requirements at 40 CFR 63.104(b) may be used in limited instances, we 
did not propose nor finalize that other provisions of 40 CFR 63.104 
apply. Instead, for example, facilities that use water sampling to 
detect leaks must still comply with the recordkeeping and reporting 
requirements of 40 CFR 63.2520(e)(16) and 40 CFR 63.2525(r). We are 
finalizing revisions at 40 CFR 63.2520(e)(16) and 40 CFR 63.2525(r) to 
specify this.
    Topic summary, PRDs with rupture disks (40 CFR 63.2480(e)(2)(ii) 
and (e)(2)(iii)): For PRDs with rupture disks, a petitioner pointed out 
that EPA agreed in their response to comment document (see docket item 
EPA-HQ-OAR-2018-0746-0200 in the MON RTR docket) to delete the second 
sentence (i.e., the requirement to conduct monitoring if rupture disks 
are replaced) from 40 CFR 63.2480(e)(2)(ii) and (e)(2)(iii). However, 
the final rule (85 FR 49084, August 12, 2020) did not reflect these 
deletions. We agreed that the language diverges from what 40 CFR part 
63, subpart UU required for PRDs. Therefore, we proposed to correct 
this error by deleting the second sentence from 40 CFR 
63.2480(e)(2)(ii) and (e)(2)(iii).
    Comments: A commenter supported the proposed revision to the 
monitoring requirements for PRDs with rupture disks and stated the 
revision provides consistency with other rules.
    Response: The EPA acknowledges the commenter's support, and we are 
finalizing the revisions as proposed.
    Topic summary, scrubber testing and monitoring requirements (40 CFR 
63.2493(a)(2)(vi) and (b)(4)): A petitioner requested clarification of 
scrubber monitoring parameters and the types of scrubbers that are 
applicable to certain requirements at 40 CFR 63.2493(a)(2)(vi) and 
(b)(4). The petitioner stated that the rule is only applicable to 
scrubbers that use an acid solution and reactant tank, but that other 
types of scrubbers are used in instances when ethylene oxide is present 
in small amounts. The petitioner requested the pH monitoring parameter 
be revised to account for other types of scrubbers. The petitioner also 
requested the temperature of the ``scrubber liquid'' be monitored 
instead of the temperature of the ``water.''
    Scrubbers that use an acid solution and reactant tank are the 
primary focus of the scrubber monitoring requirements because this type 
of scrubber liquid is necessary to specifically control ethylene oxide. 
As such, we did not propose to revise the monitoring parameters to 
apply more broadly, such as to scrubbers that use water as the 
scrubbing liquid. We proposed clarifying language that the monitoring 
requirements at 40 CFR 63.2493(a)(2)(vi) and (b)(4) are applicable to 
scrubbers ``with a reactant tank.'' We agreed with the petitioner 
regarding temperature monitoring and proposed a correction that the 
temperature of the ``scrubber liquid'' must be monitored. We also 
proposed clarifying language at 40 CFR 63.2493(a)(2)(viii) and (b)(6), 
that if a facility uses a scrubber without a reactant tank that 
provides control of ethylene oxide, the facility may establish site-
specific operating parameters.
    Comments: Commenters supported the proposed revision to the 
scrubber testing and monitoring requirements for scrubbers controlling 
ethylene oxide. In addition, a commenter recommended that the EPA only 
allow scrubbers with reactant tanks and acid solutions to control 
ethylene oxide. Another commenter also requested that the EPA allow any 
scrubber to control ethylene oxide by developing site-specific 
operating parameters, regardless of the amount of control the scrubber 
provides. This commenter stated they understood the proposal allows for 
site-specific operating parameters only if the scrubber provides 
incidental control of ethylene oxide.
    Response: We acknowledge the commenters' support and are finalizing 
the revisions as proposed. The EPA notes that in the proposed 
regulatory text changes for the MON, we did not use the phrase 
``incidental control.'' We are clarifying provisions at 40 CFR 
63.2493(a)(2)(viii) and (b)(6), which would allow an owner or operator 
who uses a scrubber without a reactant tank to request appropriate 
operating parameters from the Administrator. In the preamble of the 
proposed rule, we noted that this option would be available to 
facilities using scrubbers for incidental control, because it is likely 
that a scrubber needing to control a significant quantity of ethylene 
oxide emissions would need to be equipped with a reactant tank. It is 
unlikely that a water scrubber could provide adequate control of 
significant ethylene oxide emissions.
    Consistent with our long-standing approach of allowing regulated 
industries to determine how to meet numeric emission limits, the EPA is 
not requiring the use of acid scrubbers for the control of ethylene 
oxide. Currently, scrubbers with acid solutions are likely the only 
scrubber technology that can achieve significant control of ethylene 
oxide; however, we also acknowledge that there are some facilities with 
ethylene oxide emissions that are very low and almost meet the outlet 
concentration limit without control. These owners and operators should 
be able to use any control device that can allow them to achieve the 
emission standard. Additionally, there could be a development of new 
scrubbing technologies for ethylene oxide in the future that use a 
configuration other than acid solutions and a reactant tank. We do not 
want to limit the development of these technologies by limiting the 
control devices that owners and operators must use.
    Topic summary, storage tank ethylene oxide concentration (40 CFR 
63.2492(b)): A petitioner requested that an alternative to sampling and 
analysis of storage tank materials should be allowed, to determine if a 
storage tank is in ethylene oxide service. The petitioner stated that 
information already exists for some storage tanks to show that the 
ethylene oxide concentration in the material stored is less than 0.1 
percent by weight (sometimes significantly so) and that it is 
unnecessary to require sampling and analysis. We agreed with the 
petitioner and proposed to amend 40 CFR 63.2492(b) to allow 
calculations to be performed to show that the ethylene oxide 
concentration is less than 0.1 percent by weight of the material stored 
in the storage tank, provided the calculations rely on information 
specific to the material stored. This may include using, for example, 
specific concentration information from safety data sheets.
    Comments: Commenters supported the proposed revision to allow 
calculations to determine the ethylene oxide concentration of the fluid 
stored in a storage tank. A commenter also

[[Page 23852]]

recommended that the EPA expand this requirement and allow the use of 
engineering judgement and process knowledge to determine the 
concentration, similar to what is allowed to determine the ethylene 
oxide content for equipment leaks.
    Another commenter did not support the proposed revision to allow 
calculations to determine the ethylene oxide concentration of the fluid 
stored in a storage tank. The commenter argued that calculations 
introduce uncertainty and are often underestimated.
    A commenter also noted that proposed 40 CFR 63.2492(b)(i) and 
(b)(ii) should be renumbered to 40 CFR 63.2492(b)(1) and (b)(2).
    Response: We are finalizing the revisions to allow calculations to 
determine the ethylene oxide concentration of the fluid stored in a 
storage tank as proposed. We disagree with the commenter's request to 
add more flexibility to the alternative approach in 40 CFR 
63.2492(b)(2) for storage tanks to be consistent with the equipment 
leaks provision at 40 CFR 63.2492(c)(2). The rule is already clear 
regarding determining whether storage tanks are ``in ethylene oxide 
service.'' In order to determine the requirements for storage tanks in 
ethylene oxide service, facilities must look at both the definition of 
``in ethylene oxide service'' and the requirements in 40 CFR 63.2492 
together. The definition of ``in ethylene oxide service'' lets the 
owner or operator designate a storage tank based on process knowledge; 
however, if an owner or operator wants to say a storage tank is not in 
ethylene oxide service, they must use the procedures in 40 CFR 
63.2492(b). The rule at 40 CFR 63.2492(b)(2) already explicitly allows 
for an owner or operator to calculate the concentration of ethylene 
oxide of the fluid stored in a storage tank if information specific to 
the fluid stored is available which includes data based on safety data 
sheets.
    We do agree with the commenter that the proposed numbering was 
incorrect and are finalizing the revisions at 40 CFR 63.2492(b)(1) and 
(b)(2).
    We are also changing the phrasing of ``sampling and analysis is 
performed as specified in Sec.  63.2492'' to ``the procedures specified 
in Sec.  63.2492 are performed'' within the definition of ``in ethylene 
oxide service'' for storage tanks. This language more clearly aligns 
with the revised requirements at 40 CFR 63.2492(b).
    Topic summary, delay of repair provisions for equipment in ethylene 
oxide service (40 CFR 63.2493(d)(1)(iii) and 63.2493(d)(2)(iii)): A 
petitioner requested the EPA clarify whether delay of repair provisions 
apply to equipment in ethylene oxide service. The petitioner noted that 
in the response to comments for the final rule, the EPA stated that 
delay of repair provisions do not apply. However, the petitioner 
further noted the final rule language did not reflect this. We proposed 
to revise 40 CFR 63.2493(e) to specify that the delay of repair 
provisions of 40 CFR part 63, subparts H and UU and 40 CFR part 65, 
subpart F do not apply for all equipment in ethylene oxide service.
    Comments: Commenters did not support the proposed revision to 
remove the delay of repair provisions for equipment in ethylene oxide 
service. The commenters contended that removing the delay of repair 
provisions would increase emissions, because the emissions due to 
shutdowns can be higher than the leak emissions due to invoking delay 
of repair. This is particularly true if few components are leaking. A 
commenter emphasized that companies consider both worker safety and 
emissions when evaluating leaks and noted some companies have ambient 
air monitors for ethylene oxide. The commenters stated the number of 
components in ethylene oxide service that leak is low, and that this is 
supported by data submitted by chemical manufacturing facilities (which 
are similar to MON facilities) to the EPA which indicated no leaking 
connectors, valves, or pumps in ethylene oxide service. The commenters 
also stated the delay of repair provisions provide important 
flexibility for companies and allow them to operate without disruptions 
to their operations.
    Another commenter supported the proposed revision to remove the 
delay of repair provisions for equipment in ethylene oxide service.
    Response: We partly erred when stating at proposal that the MON 
included delay of repair provisions for equipment in ethylene oxide 
service. The final 2020 MON included specific repair requirements for 
pumps and connectors in ethylene oxide service at 40 CFR 
63.2493(d)(1)(iii) and 63.2493(d)(2)(iii), respectively. These 
requirements stipulated that a leak must be repaired within 15 days 
after it is detected. No exceptions were provided for the 15-day 
timeframe, which means there were no exceptions for delay of repair. 
Other equipment in ethylene oxide service (e.g., valves) do not have 
ethylene oxide-specific requirements in the MON like connectors and 
pumps, and it was our intent that delay of repair provisions still 
apply for this other equipment (i.e., reducing ethylene oxide emissions 
from connectors and pumps was determined to be necessary for the 2020 
rule, and thus delay of repair was not provided for them). As such, we 
are not revising the MON to exclude delay of repair provisions for 
equipment other than connectors and pumps in ethylene oxide service and 
are not finalizing the revision that was proposed at 40 CFR 
63.2493(e)(17). We are maintaining the existing requirements at 40 CFR 
63.2493(d)(1)(iii) and 63.2493(d)(2)(iii), with one additional 
revision. We are finalizing a revision that allows for the delay of 
repair for connectors and pumps in ethylene oxide service if the 
equipment is isolated from the process and does not remain in ethylene 
oxide service.
    Topic summary, LEL clarification (40 CFR 63.2450(v), 63.2470(f), 
63.2520(e)(14), 63.2525(p)): Maintenance vent and storage vessel 
degassing provisions reference the term LEL to determine compliance. We 
did not propose revisions to this term, but commenters provided 
feedback stating it was being misused.
    Comments: Commenters stated that we were misusing the term LEL in 
certain rule language provisions for maintenance vents and storage 
vessel degassing (e.g., 40 CFR 63.2450(v), 40 CFR 63.2470(f)). 
Commenters stated the LEL was a fixed physical property of a vapor 
mixture and thus does not change nor is it measured. It refers to a 
specific concentration value for a particular mixture. For example, 
commenters explained that, when opening a maintenance vent, the 
concentration of the vapor is measured and then compared to the LEL. 
The rule text incorrectly implied that the LEL of the vapor is 
measured. The commenters requested that the EPA clarify that the 
concentration of the vapors in equipment for maintenance vents (and the 
vapor space concentration for storage vessel degassing) must be less 
than 10 percent of the LEL and that facilities are to measure the 
concentration, not the LEL.
    Response: We agree with commenters that the rule text referring to 
the LEL was used incorrectly for certain maintenance vent and storage 
vessel degassing provisions and that the LEL cannot be changed for a 
vapor. We are revising the rule text to be clear that facilities 
measure the vapor concentration and then compare that concentration 
value to the LEL of the vapor to determine if the concentration is less 
than 10 percent of the LEL.

[[Page 23853]]



 Table 5--Summary of Revisions to 40 CFR Part 63, Subpart FFFF for Which
                       the EPA Received No Comment
------------------------------------------------------------------------
          Provision               Issue summary        Final revision
------------------------------------------------------------------------
40 CFR 63.2450(e)(6)(i).....  Provision contains a  The EPA is replacing
                               typographical error.  the reference to 40
                                                     CFR 63.148(h)(3)
                                                     with a reference to
                                                     40 CFR 63.148(i)(3)
                                                     to correct the
                                                     typographical
                                                     error.
40 CFR 63.2450(e)(7)........  A petitioner          The EPA is
                               requested that the    clarifying that 40
                               EPA clarify whether   CFR 63.2470(c)(3),
                               certain adsorber      40 CFR
                               provisions            63.2520(d)(6) and
                               referenced within     (e)(13), 40 CFR
                               40 CFR 63.983 and     63.2525(o), and the
                               other related         provisions
                               requirements and      referenced within
                               exceptions (i.e.,     40 CFR 63.983 all
                               40 CFR                apply (in addition
                               63.2470(c)(3), 40     to 40 CFR
                               CFR 63.2520(d)(6)     63.2450(e)(4) and
                               and (e)(13), and 40   (e)(6)) if
                               CFR 63.2525(o))       facilities reduce
                               apply to this         organic HAP
                               paragraph. The        emissions by
                               petitioner also       venting emissions
                               pointed out that it   through a closed-
                               is not clear          vent system to an
                               whether a             adsorber(s) that
                               supplement to the     cannot be
                               notification of       regenerated or a
                               compliance status     regenerative
                               (NOCS) report is      adsorber(s) that is
                               needed, and if        regenerated
                               necessary, what       offsite. We are
                               information should    also clarifying in
                               be provided.          40 CFR
                                                     63.2450(e)(1) that
                                                     40 CFR
                                                     63.2450(e)(1) does
                                                     not apply when
                                                     complying with 40
                                                     CFR 63.2450(e)(7).
                                                    As part of this
                                                     clarification, we
                                                     are also finalizing
                                                     a new requirement
                                                     at 40 CFR
                                                     63.2520(d)(6) for
                                                     adsorbers subject
                                                     to the requirements
                                                     of 40 CFR
                                                     63.2450(e)(7)
                                                     requiring a
                                                     supplement to the
                                                     NOCS report within
                                                     150 days after the
                                                     first applicable
                                                     compliance date. We
                                                     are finalizing that
                                                     the supplement to
                                                     the NOCS report
                                                     must describe
                                                     whether the
                                                     adsorber cannot be
                                                     regenerated or is a
                                                     regenerative
                                                     adsorber(s) that is
                                                     regenerated
                                                     offsite; and
                                                     specify the
                                                     breakthrough limit
                                                     and adsorber bed
                                                     life that was
                                                     established during
                                                     the initial
                                                     performance test or
                                                     design evaluation
                                                     of the adsorber.
                                                     Finally, we are
                                                     revising the
                                                     introduction
                                                     paragraph of 40 CFR
                                                     63.2520 as well as
                                                     the requirement in
                                                     40 CFR 63.2515(d)
                                                     to update the
                                                     reference to 40 CFR
                                                     63.2520(d)(6).
40 CFR 63.2460(c)(9)........  Provision contains a  The EPA is replacing
                               typographical error.  the phrase ``in
                                                     paragraphs
                                                     (c)(9)(i) through
                                                     (vi) of this
                                                     section'' with ``in
                                                     paragraphs
                                                     (c)(9)(i) through
                                                     (iv) of this
                                                     section'' to
                                                     correct the
                                                     typographical
                                                     error.
40 CFR 63.2480(a)...........  Provision contains a  The EPA is replacing
                               typographical error.  the phrase ``For
                                                     each light liquid
                                                     pump, valve, and
                                                     connector in
                                                     ethylene oxide
                                                     service'' with
                                                     ``For each light
                                                     liquid pump,
                                                     pressure relief
                                                     device, and
                                                     connector in
                                                     ethylene oxide
                                                     service'' to
                                                     correct the
                                                     typographical
                                                     error.
40 CFR 63.2480(f)(18)(iii)..  Provision contains a  The EPA is replacing
                               typographical error.  ``Sec.
                                                     63.181(b)(2)(i)''
                                                     with ``Sec.
                                                     63.181(b)(3)(i)''
                                                     to correct the
                                                     typographical
                                                     error.
40 CFR 63.2480(f)(18)(vi)...  A petitioner          We agree with the
                               contended that the    petitioner that the
                               reference to          provision should be
                               information           revised to clarify
                               required to be        that the reporting
                               reported under 40     requirement is
                               CFR                   specific to the
                               63.182(d)(2)(xiv)     recently
                               is too broad and      promulgated PRD
                               should be more        requirements.
                               narrowly described    Therefore, we are
                               as ``information in   finalizing language
                               Sec.   63.165(a)      that reads ``The
                               required to be        information in Sec.
                               reported under 40       63.165(a)
                               CFR                   required to be
                               63.182(d)(2)(xiv)''   reported under 40
                               in order to clarify   CFR
                               that the reporting    63.182(d)(2)(xiv)
                               requirement is        is now required to
                               specific to the       be reported under
                               recently              Sec.
                               promulgated PRD       63.2520(e)(15)(i)
                               requirements.         through (iii).''
40 CFR 63.2480(f)(18)(x)....  Provision contains a  The EPA is replacing
                               typographical error.  ``Sec.
                                                     63.1022(a)(1)(v)''
                                                     with ``Sec.
                                                     63.1023(a)(1)(v)''
                                                     to correct the
                                                     typographical
                                                     error.
40 CFR 63.2480(f)(18)(xiii).  A petitioner          We agree with the
                               contended that the    petitioner that the
                               reference to          provision should be
                               information           revised to clarify
                               required to be        that the reporting
                               reported under 40     requirement is
                               CFR 63.1039(b)(4)     specific to the
                               is too broad and      recently
                               should be more        promulgated PRD
                               narrowly described    requirements.
                               as ``information in   Therefore, we are
                               Sec.   63.1030(b)     finalizing language
                               required to be        that reads ``The
                               reported under 40     information in Sec.
                               CFR 63.1039(b)(4)''     63.1030(b)
                               in order to clarify   required to be
                               that the reporting    reported under 40
                               requirement is        CFR 63.1039(b)(4)
                               specific to the       is now required to
                               recently              be reported under
                               promulgated PRD       Sec.
                               requirements.         63.2520(e)(15)(i)
                                                     and (ii).''
40 CFR 63.2493(b)(2)........  A petitioner          We agree with the
                               requested that the    petitioner that 40
                               EPA include           CFR 63.2493(b)(2)
                               introductory          only applies if the
                               language to clarify   facility chooses to
                               that the              route emissions to
                               requirements apply    a non-flare control
                               only if the           device and chooses
                               facility chooses to   to comply with the
                               route emissions to    1 ppmv standard via
                               a non-flare control   CEMS. Therefore, we
                               device and chooses    are adding
                               to comply with the    introductory text
                               1 parts per million   at 40 CFR
                               volume (ppmv)         63.2493(b)(2) that
                               standard via          clarifies this.
                               continuous emission
                               monitoring systems
                               (CEMS).
40 CFR 63.2493(d)(3)........  A petitioner          We agree with the
                               contended that the    petitioner to
                               reference to          revise the
                               ``affected source''   provision for
                               should be revised     consistency with
                               to ``MCPU'' to be     Table 6 to Subpart
                               consistent with the   FFFF of part 63;
                               second column of      therefore, we are
                               Table 6 to Subpart    replacing
                               FFFF of Part 63.      ``affected source''
                                                     with ``MCPU''.
40 CFR 63.2493(d)(4)(v).....  Provision contains a  The EPA is replacing
                               typographical error.  ``Sec.
                                                     63.2445(h)'' with
                                                     ``Sec.
                                                     63.2445(i)'' to
                                                     correct the
                                                     typographical
                                                     error.

[[Page 23854]]

 
40 CFR 63.2520(d)...........  A petitioner pointed  We acknowledge there
                               out that the EPA      was an
                               indicated in the      inconsistency in
                               preamble to the       what we said in the
                               final rule (85 FR     preamble about
                               49084; August 12,     electronic
                               2020) that            reporting NOCS
                               electronic            reports versus what
                               reporting is          we required in the
                               required at 40 CFR    2020 final rule.
                               63.2520(d) for the    However, the
                               NOCS report;          inconsistency is
                               however, the final    irrelevant because
                               rule does not         in this rulemaking,
                               contain this          we are finalizing
                               requirement. The      at 40 CFR
                               petitioner            63.2520(d) to
                               requested that the    require NOCS
                               EPA clarify that      reports be
                               this was a            submitted
                               misstatement in the   electronically
                               preamble language     through the EPA's
                               and that the NOCS     CDX CEDRI. The
                               report is not         requirement to
                               required to be        submit NOCS reports
                               submitted             electronically will
                               electronically.       increase the ease
                                                     and efficiency of
                                                     data submittal and
                                                     data accessibility.
40 CFR 63.2525(o)...........  A petitioner          In the 2020 final
                               requested that the    rule, we
                               EPA update the        inadvertently did
                               recordkeeping         not revise the
                               requirements for      recordkeeping
                               adsorbers that        requirements to
                               cannot be             reflect the
                               regenerated and for   associated
                               regenerative          monitoring
                               adsorbers that are    requirements in 40
                               regenerated offsite   CFR 63.2450(e)(7)
                               to reflect the        (for adsorbers that
                               monitoring            cannot be
                               requirements in the   regenerated and for
                               final rule (85 FR     regenerative
                               49084; August 12,     adsorbers that are
                               2020).                regenerated
                               Specifically, the     offsite). We are
                               petitioner            correcting this by
                               requested that the    revising 40 CFR
                               EPA revise 40 CFR     63.2525(o)(1) and
                               63.2525(o)(1) to      (2) and removing
                               require that you      the requirement at
                               must keep records     40 CFR
                               of the breakthrough   63.2525(o)(4) in
                               limit and bed life    its entirety, as
                               for each adsorber     recommended by the
                               established           petitioner.
                               according to 40 CFR   However, we are not
                               63.2450(e)(7)(i);     revising 40 CFR
                               revise 40 CFR         63.2525(o)(3) as
                               63.2525(o)(2) to      requested by the
                               require that you      petitioner. We are
                               keep records of       keeping the
                               each outlet HAP or    language of 40 CFR
                               TOC concentration     63.2525(o)(3) as-
                               measured according    is, which aligns
                               to 40 CFR             with the language
                               63.2450(e)(7)(ii)     used in 40 CFR
                               and (e)(7)(iii);      63.2450(e)(7)(iii)(
                               and revise 40 CFR     B).
                               2525(o)(3) to
                               require records of
                               the date and time
                               each adsorber is
                               replaced. The
                               petitioner also
                               requested the EPA
                               remove the
                               requirement at 40
                               CFR 63.2525(o)(4)
                               in its entirety.
40 CFR 63.2520(e)(2)........  Provision contains a  The EPA is
                               typographical error.  correcting the
                                                     spelling of
                                                     ``paragraph.''
40 CFR 63.2450(e)(5)(iv),     Provisions needing    The EPA is removing
 63.2520(e), (f), (g), (h),    technical             duplication and
 and (i).                      clarifications or     pointing directly
                               removal.              to 40 CFR 63.9(k)
                                                     when required to
                                                     submit certain
                                                     reports to CEDRI.
                                                     Specifically,
                                                     instructions for
                                                     submitting reports
                                                     electronically
                                                     through CEDRI,
                                                     including
                                                     instructions for
                                                     submitting CBI and
                                                     asserting a claim
                                                     of EPA system
                                                     outage or force
                                                     majeure, were
                                                     recently added to
                                                     40 CFR 63.9(k) (85
                                                     FR 73885; November
                                                     19, 2020),
                                                     therefore, text
                                                     related to these
                                                     requirements is no
                                                     longer necessary in
                                                     the MON.
------------------------------------------------------------------------

F. Other Petroleum Refinery MACT 1 Technical Corrections and 
Clarifications

    There are additional revisions that we are finalizing for the 
Petroleum Refinery MACT 1 to address other technical corrections and 
clarifications and to correct typographical errors. Refer to section 
III.C.4. of the preamble to the proposed rule for the additional 
details.\33\
---------------------------------------------------------------------------

    \33\ 88 FR 25587 (Apr. 27, 2023).
---------------------------------------------------------------------------

    Issue summary, pressure-assisted flares (40 CFR 63.641, 63.655, and 
63.670): We proposed amendments to Petroleum Refinery MACT 1 that are 
consistent with flaring provisions in other recent rules (i.e., EMACT 
standards) that adopted the Petroleum Refinery MACT 1 flare 
requirements but addressed additional issues, such as adding provisions 
for pressure-assisted flares. The proposed amendments include adding 
pressure-assisted flares to the definition of the term ``flare'' in 40 
CFR 63.641 and adding appropriate requirements for pressure-assisted 
flares in 40 CFR 63.670. These amendments are consistent with the EPA's 
intention that all types of flares, including pressure-assisted flares, 
are covered by the provisions in Petroleum Refinery MACT 1. The 
proposed amendments for pressure-assisted flares include pilot flame 
standards and requirements for cross-lighting in 40 CFR 63.670(b), 
pressure monitoring in 40 CFR 63.670(d)(3), higher combustion zone 
operating limits in 40 CFR 63.670(e), and requirements to use only the 
direct calculation methods for determining the flare vent gas net 
heating value according to 40 CFR 63.670(l)(5)(ii). We also proposed 
reporting and recordkeeping requirements specific to pressure-assisted 
flares in 40 CFR 63.655(g)(11)(iii) and (i)(9)(vi), respectively.
    Comment: Two commenters supported the proposed revisions for 
pressure-assisted flare requirements. A commenter stated the proposed 
revisions would reduce burden on the regulated facilities, permitting 
authorities, and the EPA. Another commenter requested clarification on 
whether existing AMELs would be affected and whether owners and 
operators could still request an AMEL in the future.
    Response: The EPA acknowledges the commenters' support and we are 
finalizing the revisions as proposed. We confirm that owners and 
operators can still request an AMEL to demonstrate appropriate flare 
combustion efficiency, if so desired by an owner or operator. The 
proposed revisions did not impact the AMEL requirements of 40 CFR 
63.670(r). We also confirm that existing AMELs are unaffected by the 
proposed revisions to the NESHAP requirements.
    Topic summary, flare gas composition monitoring requirements (40 
CFR 63.671): To provide additional flexibility to the monitoring 
requirements for flare gas composition as required by 40 CFR 63.670(j), 
we proposed to add mass spectrometry as a method in 40 CFR 63.671. The 
current provisions in 40 CFR 63.671 could be interpreted to suggest 
that gas chromatographs must be used for flare

[[Page 23855]]

gas compositional analysis. This was not our intent. We recognize that 
there are some methods, like mass spectrometry, which can determine 
flare gas composition without the use of a gas chromatograph. We 
proposed to add specific requirements for calibration and operation of 
mass spectrometers that parallel the requirements for gas 
chromatographs.
    Comment: One commenter provided specific rule text edits to 
multiple provisions within 40 CFR 63.671(e) and (f). The commenter 
recommended including language specific to ``gas chromatograph'' in 40 
CFR 63.671(e); adding reference to the seven-day calibration error test 
period in 40 CFR 63.671(e)(4); stipulating that net heating value (NHV) 
calculations must use individual component properties in Table 12 to 40 
CFR part 63, subpart CC in 63.671(e)(4)(ii); removing ``without the use 
of gas chromatography'' in 40 CFR 63.671(f); adding specificity on 
using low, mid, and high-level calibration gas cylinders in 40 CFR 
63.671(f)(2); and revising the calibration requirements for ``net 
heaving value by mass spectrometer'' in Table 13 to 40 CFR part 63, 
subpart CC.
    Response: First, we noted that there was no difference between the 
regulatory language from the commenter and the proposed rule revisions 
for 40 CFR 63.671(e), therefore no changes were considered for this 
provision.
    Next, we considered the commenter recommended revisions to 40 CFR 
63.671(e)(4). It appears this suggested revision is intended to clarify 
that consistent with Performance Specification 9, an initial 
calibration error test must occur over a 7-day period followed by daily 
calibration with mid-level calibration standard for each analyte and 
quarterly performance audits. We have finalized clarifying language in 
40 CFR 63.671(e)(4) consistent with our understanding of the 
commenter's intent as follows, ``The owner or operator must initially 
determine the average instrument calibration error the during the 7-Day 
Calibration Error Test Period and subsequently perform daily 
calibration and quarterly audits using either the compound-specific 
calibration error method provided in paragraph (i) of this section or 
using the NHV method provided in paragraph (ii) of this section.''
    The commenter also suggested a clarifying edit to the definition of 
equation term ``NHV measured'' to specify that NHV calculations are to 
be made based on the individual component properties listed in Table 
12. We find that the suggested edit improves clarity that the 
individual components and respective properties are contained in Table 
12 to 40 CFR part 63, subpart CC, and have finalized this edit 
consistent with the commenter's suggestion.
    We are not finalizing any amendments to the proposed new 
introductory paragraph in 40 CFR 63.671(f) as per the commenter's 
recommendation to strike ``without the use of gas chromatography.'' 
This language provides the clarification that the provisions in 40 CFR 
63.671(f) are limited in applicability to continuous mass spectrometers 
that do not use gas chromatography. We are, however, finalizing the 
commenter's recommended revision to 40 CFR 63.671(f)(2) to add the 
characterizing language (i.e., low-, mid-, high-) relative to the 
calibration gas cylinders as this language is consistent with 
Performance Specification 9 specific in sections 7.1.1-7.1.3.
    Finally, we are finalizing the proposed amendments to Table 13 to 
40 CFR part 63, subpart CC, as proposed, by cross referencing 
Performance Specification 9 rather than referring to the requirements 
in 40 CFR 63.671(e)(4) and (f). Performance Specification 9 includes 
additional requirements than are listed in 40 CFR 63.671(e)(4) and (f). 
For example, in section 10.2 of Performance Specification 9, if the 
instrument average response varies by more than 10 percent of the 
certified concentration value of the cylinder for an analyte, the owner 
or operator must immediately inspect the instrument making any 
necessary adjustments and conduct an initial multi-point calibration in 
accordance with section 10.1. We intended for affected sources to 
comply fully with the calibration and quality control requirements in 
Performance Specification 9 and thus are maintaining the cross 
reference in Table 13 to 40 CFR part 63, subpart CC.
    Topic summary, Alternate Test Method for flare fuel measurements 
(40 CFR 63.671(e)): The EPA approved an Alternate Test Method to use 
NHV in place of component heat content (i.e., British thermal units 
``BTU'') for select quality control criteria in 40 CFR part 63, subpart 
CC flare fuel measurements (herein referred to as ALT-131) in December 
2018. See 84 FR 7363, 7364 (March 4, 2019).
    Comment: The commenter requested that the EPA clarify whether the 
ability to use this approved Alternate Method 131 is affected by this 
rulemaking.
    Response: We confirm that the approval of ALT-131 will be 
unaffected by this rulemaking and facilities can continue to utilize 
ALT-131 for compliance with flare measurement requirements in 40 CFR 
63.671(e) and by reference, 40 CFR part 60, appendix B, Performance 
Specification 9 (PS 9) for determining NHV.
    Topic summary, LEL clarification (40 CFR 63.643(c), 63.655(g)(13), 
63.655(i)(12)): Maintenance vent provisions reference the term LEL to 
determine compliance. We did not propose revisions to this term but 
commenters provided feedback stating it was being misused.
    Comments: Commenters stated that we were misusing the term LEL in 
certain rule language provisions for maintenance vents (e.g., 40 CFR 
63.643(c)(1)). Commenters stated the LEL was a fixed physical property 
of a vapor mixture and thus does not change nor is it measured. It 
refers to a specific concentration value for a particular mixture. For 
example, when opening a maintenance vent, commenters elaborated that 
you measure the concentration of the vapor and then you can compare 
that concentration to the LEL. The rule text incorrectly implied that 
the LEL of the vapor is measured. The commenters requested that the EPA 
clarify that the concentration of the vapors in equipment for 
maintenance vents must be less than 10 percent of the LEL and that 
facilities are to measure the concentration, not the LEL.
    Response: We agree with commenters that the rule text referring to 
the LEL was used incorrectly for certain maintenance vent and storage 
vessel degassing provisions and that the LEL cannot be changed for a 
vapor. We are revising the rule text to be clear that facilities 
measure the vapor concentration and then compare that concentration 
value to the LEL of the vapor to determine if the concentration is less 
than 10 percent of the LEL.

G. What compliance dates are we finalizing?

    We are finalizing new compliance dates for certain revisions to the 
EMACT standards, OLD NESHAP, MON, and Petroleum Refinery MACT 1. We did 
not propose new compliance dates for the EMACT standards, OLD NESHAP, 
and MON because the rules that were promulgated in 2020 had still not 
come into full effect at the time of proposal in April 2023. The 
compliance dates were also not stayed as part of this reconsideration 
action. The compliance dates for the 2020 rules have now passed and 
owners and operators must have been complying with the EMACT standards 
by July 6, 2023, the OLD NESHAP by July 7, 2023, and the MON by August 
12, 2023. Most of the revisions we are finalizing do not

[[Page 23856]]

impose substantial new requirements, but rather either provide clarity 
to the rules for owners and operators or are alternative requirements. 
As such, we are providing new compliance dates for the EMACT standards, 
OLD NESHAP, and MON for revisions related to the removal of the force 
majeure provisions only and are not changing the compliance dates for 
any other revisions to these rules.
    For the removal of the force majeure provisions from the PRD and 
emergency flaring work practice standards for each rule and for most 
actions that we are finalizing for the Petroleum Refinery MACT 1, 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 to make any necessary adjustments, including 
adjusting standard operating procedures and converting reporting 
mechanisms to install necessary hardware and software. The EPA 
recognizes the confusion that multiple 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 revised requirements, the EPA considers a period of 
60 days after the effective date of the final rule to be the most 
expeditious compliance period practicable. Therefore, for the EMACT 
Standards, OLD NESHAP, MON, and Petroleum Refinery MACT 1, we are 
finalizing that the force majeure provisions shall be fully removed 
from the PRD and emergency flaring work practice standards as of 60 
days after the effective date of the final rule. For the Petroleum 
Refinery MACT 1, we are also finalizing that affected sources must be 
in compliance with most other revisions upon initial startup or within 
60 days of the effective date of the final rule, whichever is later.
    We are finalizing that petroleum refinery owners or operators may 
comply with the new operating and monitoring requirements for flares 
upon initial startup or by the effective date of the final rule, 
whichever is later. We believe that compliance with the flare 
requirements immediately upon finalizing the rule is necessary to 
ensure that pressure-assisted flares are appropriately operated.

IV. Summary of Cost, Environmental and Economic Impacts

A. What are the affected facilities?

    In our final RTRs, we estimated the following:
    There are 26 facilities subject to the EMACT standards that are 
currently operating and five additional facilities under construction. 
A complete list of known facilities in the EMACT standards is available 
in Appendix A of the memorandum, Review of the RACT/BACT/LAER 
Clearinghouse Database for the Ethylene Production Source Category (see 
Docket Item No. EPA-HQ-OAR-2017-0357-0008 in the EMACT RTR docket).
    There are 173 OLD NESHAP facilities currently operating and four 
additional OLD NESHAP facilities under construction. A complete list of 
known OLD NESHAP facilities is available in Appendix A of the 
memorandum, National Impacts of the 2020 Risk and Technology Review 
Final Rule for the Organic Liquids Distribution (Non-Gasoline) Source 
Category (see Docket Item No. EPA-HQ-OAR-2018-0746-0069 in the OLD 
NESHAP RTR docket).
    There are 201 MON facilities currently operating. A complete list 
of known MON facilities is available in Appendix 1 of the memorandum, 
Residual Risk Assessment for the Miscellaneous Organic Chemical 
Manufacturing Source Category in Support of the 2019 Risk and 
Technology Review Proposed Rule (see Docket Item No. EPA-HQ-OAR-2018-
0746-0011 in the MON RTR docket).
    Additionally, based on the Energy Information Administration's 2021 
Refinery Capacity Report, there are 129 operable petroleum refineries 
in the United States (U.S.) and the U.S. territories, all of which are 
expected to be major sources of HAP emissions.

B. What are the air quality impacts?

    We did not estimate baseline emissions or emissions reductions for 
the revisions. None of the revisions have a direct and quantifiable 
impact on emissions because they are minor revisions to existing 
requirements.

C. What are the cost impacts?

    We expect minimal to no cost impacts due to the revisions. There 
could be minor costs for affected facilities related to reading the 
rule, making minor updates to operating procedures in some limited 
cases, and making minor adjustments to reporting systems. A few 
revisions provide slightly greater flexibility and could yield minor 
cost savings. Any potential costs or cost savings are expected to be 
negligible.

D. What are the economic impacts?

    No economic impacts are anticipated due to the revisions because 
any potential cost impacts are expected to be very minor.

E. What are the benefits?

    The proposed revisions are not expected to yield air quality 
benefits because emissions will not be affected. However, the revisions 
should improve clarity, monitoring, compliance, and implementation of 
the rules for the affected source categories.

F. What analysis of environmental justice did we conduct?

    The revisions are not expected to impact emissions and therefore we 
did not conduct an environmental justice analysis. However, 
environmental justice analyses were conducted for the final 2020 rules 
for the EMACT standards, OLD NESHAP, and MON.\34\
---------------------------------------------------------------------------

    \34\ 85 FR 40415 (Jul. 6, 2020); 85 FR 40757 (Jul. 7, 2020); and 
85 FR 49129 (Aug. 12, 2020).
---------------------------------------------------------------------------

V. Statutory and Executive Order Reviews

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

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

    This action is not a significant regulatory action as defined in 
Executive Order 12866, as amended by Executive Order 14094, and was 
therefore not subject to a requirement for Executive Order 12866 
review.

B. Paperwork Reduction Act (PRA)

    This action does not impose any new information collection burden 
under the PRA for the EMACT standards, OLD NESHAP, MON, or the 
Petroleum Refinery MACT 1. We finalized certain technical revisions, 
including new electronic reporting provisions for the PRD and emergency 
flaring work practice standard, but the technical revisions do not 
result in changes to the information collection burden. The final 
amendments require facilities to submit the work practice related data 
using an EPA provided spreadsheet template electronically through CDX 
using CEDRI. These data would not be expected to also be included in a 
facility's submission to the delegated State authority and/or EPA 
Regional Office such that no duplication is expected. The amendments to 
the mode of reporting of the work practice

[[Page 23857]]

standard-related data are not expected to change the current burden 
under the PRA and we did not revise the information collection request 
(ICR) for the rules. The Office of Management and Budget (OMB) has 
previously approved the information collection activities contained in 
the existing regulations at 40 CFR part 63, subpart YY and has assigned 
OMB control number 2060-0489; 40 CFR part 63, subpart EEEE and has 
assigned OMB control number 2060-0539; 40 CFR part 63, subpart FFFF and 
has assigned OMB control number 2060-0533; and 40 CFR part 63, subpart 
CC and has assigned OMB control number 2060-0340.

C. Regulatory Flexibility Act (RFA)

    I certify that 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 already 
identified in the 2020 final rules for the EMACT standards, OLD NESHAP, 
MON, and the 2015 final rule for Petroleum Refineries. The amendments 
to 40 CFR part 63, subparts CC, YY, EEEE, and FFFF would only minimally 
change the existing requirements for all entities. There could be minor 
costs for affected facilities related to reading the final rule, making 
minor updates to operating procedures in some limited cases, and making 
minor adjustments to reporting systems. A few revisions provide 
slightly greater flexibility and could yield minor cost savings. Any 
potential costs or cost savings are negligible.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more as described in UMRA, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. While this action 
creates an enforceable duty on the private sector, the annual cost does 
not exceed $100 million or more.

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. It will not have substantial new direct effects 
on Tribal governments, on the relationship between the Federal 
Government and Indian Tribes, or on the distribution of power and 
responsibilities between the Federal Government and Indian Tribes, as 
specified in Executive Order 13175. Thus, Executive Order 13175 does 
not apply to this action.

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

    Executive Order 13045 directs federal agencies to include an 
evaluation of the health and safety effects of the planned regulation 
on children in Federal health and safety standards and explain why the 
regulation is preferable to potentially effective and reasonably 
feasible alternatives. This action is not subject to Executive Order 
13045 because it is not a significant regulatory action under section 
3(f)(1) of Executive Order 12866, and because the EPA does not believe 
the environmental health or safety risks addressed by this action 
present a disproportionate risk to children.

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

    This action is not subject to Executive Order 13211, because it is 
not a significant regulatory action under Executive Order 12866.

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

    This rulemaking involves technical standards. The EPA has decided 
to use Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 3B, 4, 5, 18, 21, 22, 25, 
25A, 27, and 29 of 40 CFR part 60, appendix A; 301, 316, and 320 of 40 
CFR part 63, appendix A; and 602 and 624 of 40 CFR part 136, appendix 
A.
    While the EPA identified candidate VCS as being potentially 
applicable, the Agency decided not to use the VCS identified. The use 
of voluntary consensus standards 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 data 
and other important technical and policy considerations. Additional 
information for the VCS search and determinations can be found in the 
memorandum, Voluntary Consensus Standard Results for National Emission 
Standards for Hazardous Air Pollutants: for Ethylene Production, 
Miscellaneous Organic Chemical Manufacturing, Organic Liquids 
Distribution (Non-Gasoline), and Petroleum Refineries, which is 
available in the docket for this action.
    The following standards appear in the amendatory text of this 
document and were previously approved for the locations in which they 
appear: SW-846-5031, SW-846-8260D, and SW-846-5030B.

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

    The EPA believes that this type of action does not concern human 
health or environmental conditions and therefore cannot be evaluated 
with respect to potentially disproportionate and adverse effects on 
communities with environmental justice concerns. As discussed in 
section IV.F. of this preamble, the revisions are not expected to 
impact emissions, and thus, no changes to human health or environmental 
conditions are expected.
    Although this action does not concern human health or environmental 
conditions, the EPA identified and addressed environmental justice 
concerns when conducting analyses for the final 2020 rules for the 
EMACT standards, OLD NESHAP, and MON. Further information regarding 
these environmental justice analyses is available at 85 FR 40415 (July 
6, 2020), 85 FR 40757 (July 7, 2020), and 85 FR 49129 (August 12, 
2020), respectively.

K. Congressional Review Act (CRA)

    This action is subject to the CRA, and the EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the United States. This action is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects in 40 CFR Part 63

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

Michael S. Regan,
Administrator.

    For the reasons stated in the preamble, the Environmental 
Protection Agency amends part 63 of title 40, chapter I, of the Code of 
Federal Regulations as follows:

[[Page 23858]]

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

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

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

Subpart CC--National Emission Standards for Hazardous Air 
Pollutants From Petroleum Refineries

0
2. Amend Sec.  63.641 by revising the entry ``Flare'' to read as 
follows:


Sec.  63.641  Definitions.

* * * * *
    Flare means a combustion device lacking an enclosed combustion 
chamber that uses an uncontrolled volume of ambient air to burn gases. 
For the purposes of this rule, the definition of flare includes, but is 
not necessarily limited to, pressure-assisted flares, air-assisted 
flares, steam-assisted flares, and non-assisted flares.
* * * * *

0
3. Amend Sec.  63.643 by revising and republishing paragraphs (c)(1) 
and (2) to read as follows:


Sec.  63.643  Miscellaneous process vent provisions.

* * * * *
    (c) * * *
    (1) Prior to venting to the atmosphere, process liquids are removed 
from the equipment as much as practical and the equipment is 
depressured to a control device meeting requirements in paragraphs 
(a)(1) or (2) of this section, a fuel gas system, or back to the 
process until one of the following conditions, as applicable, is met.
    (i) The concentration of the vapor in the equipment served by the 
maintenance vent is less than 10 percent of its lower explosive limit 
(LEL).
    (ii) If there is no ability to measure the concentration of the 
vapor in the equipment based on the design of the equipment, the 
pressure in the equipment served by the maintenance vent is reduced to 
5 pounds per square inch gauge (psig) or less. Upon opening the 
maintenance vent, active purging of the equipment cannot be used until 
the concentration of the vapors in the maintenance vent (or inside the 
equipment if the maintenance is a hatch or similar type of opening) is 
less than 10 percent of its LEL.
    (iii) The equipment served by the maintenance vent contains less 
than 72 pounds of total volatile organic compounds (VOC).
    (iv) If the maintenance vent is associated with equipment 
containing pyrophoric catalyst (e.g., hydrotreaters and hydrocrackers) 
and a pure hydrogen supply is not available at the equipment at the 
time of the startup, shutdown, maintenance, or inspection activity, the 
concentration of the vapor in the equipment must be less than 20 
percent of its LEL, except for one event per year not to exceed 35 
percent of its LEL.
    (v) If, after applying best practices to isolate and purge 
equipment served by a maintenance vent, none of the applicable 
criterion in paragraphs (c)(1)(i) through (iv) of this section can be 
met prior to installing or removing a blind flange or similar equipment 
blind, the pressure in the equipment served by the maintenance vent is 
reduced to 2 psig or less. Active purging of the equipment may be used 
provided the equipment pressure at the location where purge gas is 
introduced remains at 2 psig or less.
    (2) Except for maintenance vents complying with the alternative in 
paragraph (c)(1)(iii) of this section, the owner or operator must 
determine the concentration of the vapor or, if applicable, equipment 
pressure using process instrumentation or portable measurement devices 
and follow procedures for calibration and maintenance according to 
manufacturer's specifications.
* * * * *

0
4. Amend Sec.  63.648 by revising paragraphs (j)(3)(iv), (j)(3)(v)(B) 
and (C), (j)(6) introductory text, and (j)(6)(ii) to read as follows:


Sec.  63.648  Equipment leak standards.

* * * * *
    (j) * * *
    (3) * * *
    (iv) The owner or operator shall determine the total number of 
release events that occurred during the calendar year for each affected 
pressure relief device separately. Prior to June 3, 2024, the owner or 
operator shall also determine the total number of release events for 
each pressure relief device for which the root cause analysis concluded 
that the root cause was a force majeure event, as defined in this 
subpart.
    (v) * * *
    (B) Prior to June 3, 2024, a second release event not including 
force majeure events from a single pressure relief device in a 3 
calendar year period for the same root cause for the same equipment. On 
and after June 3, 2024, a second release event from a single pressure 
relief device in a 3 calendar year period for the same root cause for 
the same equipment.
    (C) Prior to June 3, 2024, a third release event not including 
force majeure events from a single pressure relief device in a 3 
calendar year period for any reason. On and after June 3, 2024, a third 
release event from a single pressure relief device in a 3 calendar year 
period for any reason.
* * * * *
    (6) Root cause analysis and corrective action analysis. A root 
cause analysis and corrective action analysis must be completed as soon 
as possible, but no later than 45 days after a release event. Special 
circumstances affecting the number of root cause analyses and/or 
corrective action analyses are provided in paragraphs (j)(6)(i) through 
(iii) of this section.
* * * * *
    (ii) Prior to June 3, 2024, you may conduct a single root cause 
analysis and corrective action analysis for a single emergency event 
that causes two or more pressure relief devices to release, regardless 
of the equipment served, if the root cause is reasonably expected to be 
a force majeure event, as defined in this subpart.
* * * * *

0
5. Amend Sec.  63.655 by:
0
a. Revising paragraphs (g) introductory text, (g)(10) introductory 
text, (g)(10)(iv), (g)(11) introductory text, (g)(11)(iii) and (iv), 
and (g)(13)(iii);
0
b. Adding paragraph (i)(9)(vi); and
0
c. Revising paragraphs (i)(11)(ii), (i)(12)(ii), (i)(12)(iii), 
(i)(12)(v), and (i)(12)(vi).
    The addition and revisions read as follows:


Sec.  63.655  Reporting and recordkeeping requirements.

* * * * *
    (g) The owner or operator of a source subject to this subpart shall 
submit Periodic Reports no later than 60 days after the end of each 6-
month period when any of the information specified in paragraphs (g)(1) 
through (7) of this section or paragraphs (g)(9) through (14) of this 
section is collected. The first 6-month period shall begin on the date 
the Notification of Compliance Status report is required to be 
submitted. A Periodic Report is not required if none of the events 
identified in paragraphs (g)(1) through (7) of this section or 
paragraphs (g)(9) through (14) of this section occurred during the 6-
month period unless emissions averaging is utilized. Quarterly reports 
must be submitted for emission points included in emission averages, as 
provided in paragraph (g)(8) of this section. An owner or operator may 
submit reports required by other regulations in place of or as part of 
the Periodic Report required by this paragraph (g) if the reports 
contain the

[[Page 23859]]

information required by paragraphs (g)(1) through (14) of this section. 
The Periodic Report must contain company identifier information 
(including the company name and address), the beginning and ending 
dates of the time period covered by the report, and the information 
specified in paragraphs (g)(1) through (14) of this section, and it 
must be submitted in accordance with Sec.  63.10(a) of this part. On or 
after April 4, 2024, upon initial startup, or once the form has been 
available on the CEDRI website for six months, whichever date is later, 
owners or operators must submit all subsequent Periodic Reports in 
accordance with Sec.  63.10(a) of this part except for the items in 
paragraphs (g)(10)(iv) and (11)(iv) of this section. The items in 
paragraphs (g)(10)(iv) and (11)(iv) of this section must be submitted 
using the appropriate electronic report template on the CEDRI website 
(https://www.epa.gov/electronic-reporting-air-emissions/cedri) for this 
subpart and following the procedure specified in Sec.  63.9(k), except 
any medium submitted through mail must be sent to the attention of the 
Refinery Sector lead. The date report templates become available will 
be listed on the CEDRI website. Unless the Administrator or delegated 
state agency or other authority has approved a different schedule for 
submission of reports, the report must be submitted by the deadline 
specified in this subpart, regardless of the method in which the report 
is submitted.
* * * * *
    (10) For pressure relief devices subject to the requirements Sec.  
63.648(j), Periodic Reports must include the information specified in 
paragraphs (g)(10)(i) through (iv) of this section. Owners or operators 
must submit the Periodic Report in accordance with Sec.  63.10(a) of 
this part. On or after April 4, 2024 or once the report template for 
this subpart has been available on the CEDRI website for six months, 
whichever date is later, owners or operators must submit subsequent 
Periodic Reports in accordance with Sec.  63.10(a) of this part except 
for the items in paragraph (iv) of this section. The items in paragraph 
(iv) of this section must be submitted using the appropriate electronic 
report template on the CEDRI website for this subpart and following the 
procedures specified in Sec.  63.9(k), except any medium submitted 
through mail must be sent to the attention of the Refinery Sector lead. 
The date report templates become available will be listed on the CEDRI 
website. Unless the Administrator or delegated state agency or other 
authority has approved a different schedule for submission of reports, 
the report must be submitted by the deadline specified in this subpart, 
regardless of the method in which the report is submitted.
* * * * *
    (iv) For each pressure release to the atmosphere during the 
reporting period from a pressure relief device in organic HAP service 
subject to Sec.  63.648(j)(3), report the following information:
    (A) Pressure relief device identification name or number.
    (B) The start time and date of the pressure release.
    (C) The duration of the pressure release (in hours).
    (D) An estimate of the mass quantity of each organic HAP released 
(in pounds).
    (E) The results of any root cause analysis and corrective action 
analysis completed during the reporting period, including the 
corrective actions implemented during the reporting period and, if 
applicable, the implementation schedule for planned corrective actions 
to be implemented subsequent to the reporting period.
    (11) For flares subject to Sec.  63.670, Periodic Reports must 
include the information specified in paragraphs (g)(11)(i) through (iv) 
of this section. Owners or operators must submit the Periodic Report in 
accordance with Sec.  63.10(a) of this part. On or after April 4, 2024 
or once the report template for this subpart has been available on the 
CEDRI website for six months, whichever date is later, owners or 
operators must submit subsequent Periodic Reports in accordance with 
Sec.  63.10(a) of this part except for the items in paragraph (iv) of 
this section. The items in paragraph (iv) of this section must be 
submitted using the appropriate electronic report template on the CEDRI 
website and following the procedures specified in Sec.  63.9(k), except 
any medium submitted through mail must be sent to the attention of the 
Refinery Sector lead. The date report templates become available will 
be listed on the CEDRI website. Unless the Administrator or delegated 
State agency or other authority has approved a different schedule for 
submission of reports, the report must be submitted by the deadline 
specified in this subpart, regardless of the method in which the report 
is submitted.
* * * * *
    (iii) The 15-minute block periods for which the applicable 
operating limits specified in Sec.  63.670(d) through (f) are not met. 
Indicate the date and time for the period, the type of deviation (e.g., 
flare tip velocity, valve position for pressure-assisted flares, 
combustion zone net heating value, or net heating value dilution 
parameter) and the flare tip velocity, if applicable, and the net 
heating value operating parameter(s) determined following the methods 
in Sec.  63.670(k) through (n) as applicable.
    (iv) An indication whether there were any flaring events meeting 
the criteria in Sec.  63.670(o)(3) that occurred during the reporting 
period. If there were flaring events meeting the criteria in Sec.  
63.670(o)(3), report the following information for each such flaring 
event:
    (A) Flare identification name or number.
    (B) The type of flaring event.
    (C) The start and stop time and date of the flaring event.
    (D) The length of time (in minutes) for which emissions were 
visible from the flare during the event.
    (E) The periods of time that the flare tip velocity exceeds the 
maximum flare tip velocity determined using the methods in Sec.  
63.670(d)(2) and the maximum 15-minute block average flare tip velocity 
recorded during the event.
    (F) Results of the root cause and corrective actions analysis 
completed during the reporting period, including the corrective actions 
implemented during the reporting period and, if applicable, the 
implementation schedule for planned corrective actions to be 
implemented subsequent to the reporting period.
* * * * *
    (13) * * *
    (iii) The lower explosive limit, vessel pressure, or mass of VOC in 
the equipment, as applicable, at the start of atmospheric venting. If 
the 5 psig vessel pressure option in Sec.  63.643(c)(1)(ii) was used 
and active purging was initiated while the concentration of the vapors 
was 10 percent or greater of its LEL, also include the concentration of 
the vapors at the time active purging was initiated.
* * * * *
    (i) * * *
    (9) * * *
    (vi) On and after April 4, 2024, for pressure-assisted flares, 
retain records of pressure and valve positions as required in Sec.  
63.670(d)(3) for a minimum of 2 years, records of when valve position 
was not correct for measured pressure for 5 years, and records of a 
cross-light performance demonstration as specified in Sec.  
63.670(b)(2) for 5 years.
* * * * *
    (11) * * *
    (ii) Records of the number of releases during each calendar year 
and, prior to June 3, 2024, the number of those releases for which the 
root cause was determined to be a force majeure event.

[[Page 23860]]

Keep these records for the current calendar year and the past five 
calendar years.
* * * * *
    (12) * * *
    (ii) If complying with the requirements of Sec.  63.643(c)(1)(i) 
and the concentration of the vapor at the time of the vessel opening 
exceeds 10 percent of its LEL, identification of the maintenance vent, 
the process units or equipment associated with the maintenance vent, 
the date of maintenance vent opening, and the concentration of the 
vapor at the time of the vessel opening.
    (iii) If complying with the requirements of Sec.  63.643(c)(1)(ii) 
and either the vessel pressure at the time of the vessel opening 
exceeds 5 psig or the concentration of the vapor at the time of the 
active purging was initiated exceeds 10 percent of its LEL, 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, the date of maintenance vent 
opening, the pressure of the vessel or equipment at the time of 
discharge to the atmosphere and, if applicable, the concentration of 
the vapors in the equipment when active purging was initiated.
* * * * *
    (v) If complying with the requirements of Sec.  63.643(c)(1)(iv), 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, records documenting the lack of a 
pure hydrogen supply, the date of maintenance vent opening, and the 
concentration of the vapors in the equipment at the time of discharge 
to the atmosphere for each applicable maintenance vent opening.
    (vi) If complying with the requirements of Sec.  63.643(c)(1)(v), 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, records documenting actions taken 
to comply with other applicable alternatives and why utilization of 
this alternative was required, the date of maintenance vent opening, 
the equipment pressure and concentration of the vapors in the equipment 
at the time of discharge, an indication of whether active purging was 
performed and the pressure of the equipment during the installation or 
removal of the blind if active purging was used, the duration the 
maintenance vent was open during the blind installation or removal 
process, and records used to estimate the total quantity of VOC in the 
equipment at the time the maintenance vent was opened to the atmosphere 
for each applicable maintenance vent opening.

0
6. Amend Sec.  63.670 by:
0
a. Revising paragraphs (b) and (d) introductory text;
0
b. Adding paragraph (d)(3);
0
c. Revising paragraphs (e), (l)(5) introductory text, (o)(4)(iv), 
(o)(6), and (o)(7)(ii) through (o)(7)(v).
    The addition and revisions read as follows:


Sec.  63.670  Requirements for flare control devices.

* * * * *
    (b) Pilot flame presence. The owner or operator shall operate each 
flare with a pilot flame present on an individual burner or stage of 
burners at all times when regulated material is routed to the flare. 
Each 15-minute block during which there is at least one minute where no 
pilot flame on an individual burner or stage of burners is present when 
regulated material is routed to the flare is a deviation of the 
standard. Deviations in different 15-minute blocks from the same event 
are considered separate deviations. The owner or operator shall monitor 
for the presence of a pilot flame on an individual burner or stage of 
burners as specified in paragraph (g) of this section. Beginning on 
April 4, 2024, pressure-assisted flares using stages of burners that 
cross-light must also comply with paragraphs (b)(1) and (2) of this 
section.
    (1) Each stage of burners that cross-lights in the pressure-
assisted flare must have at least two pilots with at least one 
continuously lit and capable of igniting all regulated material that is 
routed to that stage of burners.
    (2) Unless the owner or operator of a pressure-assisted flare 
chooses to conduct a cross-light performance demonstration as specified 
in this paragraph, the owner or operator must ensure that if a stage of 
burners on the flare uses cross-lighting, that the distance between any 
two burners in series on that stage is no more than 6 feet when 
measured from the center of one burner to the next burner. A distance 
greater than 6 feet between any two burners in series may be used 
provided the owner or operator complies with the requirements in 
paragraphs (b)(2)(i) through (iii) of this section.
    (i) You must conduct a performance demonstration that confirms the 
pressure-assisted flare will cross-light a minimum of three burners and 
the spacing between the burners and location of the pilot flame must be 
representative of the projected installation.
    (ii) The compliance demonstration must be approved by the 
permitting authority and a copy of this approval must be maintained 
onsite.
    (iii) The compliance demonstration report must include the 
information in paragraphs (b)(2)(iii)(A) through (K) of this section.
    (A) A protocol describing the test methodology used, associated 
test method QA/QC parameters.
    (B) The waste gas composition and NHVcz of the gas tested.
    (C) The velocity of the waste gas tested.
    (D) The pressure-assisted multi-point flare burner tip pressure.
    (E) The time, length, and duration of the test.
    (F) Records of whether a successful cross-light was observed over 
all of the burners and the length of time it took for the burners to 
cross-light.
    (G) Records of maintaining a stable flame after a successful cross-
light and the duration for which this was observed.
    (H) Records of any smoking events during the cross-light.
    (I) Waste gas temperature.
    (J) Meteorological conditions (e.g., ambient temperature, 
barometric pressure, wind speed and direction, and relative humidity) 
during the demonstration.
    (K) An indication whether there were any observed flare flameouts 
and if so, the number and duration of each flare flameout.
* * * * *
    (d) Flare tip velocity. Except as provided in paragraph (d)(3) of 
this section for pressure-assisted flares, for each flare, the owner or 
operator shall comply with either paragraph (d)(1) or (2) of this 
section, provided the appropriate monitoring systems are in-place, 
whenever regulated material is routed to the flare for at least 15-
minutes and the flare vent gas flow rate is less than the smokeless 
design capacity of the flare.
* * * * *
    (3) Pressure-assisted flares are not subject to the flare tip 
velocity limits in either paragraph (d)(1) or (2) of this section. In 
lieu of the flare tip velocity limits, beginning on April 4, 2024, the 
owner or operator of a pressure-assisted flare must install and operate 
pressure monitor(s) on the main flare header, as well as a valve 
position indicator monitoring system for each staging valve to ensure 
that the flare operates within the proper range of conditions as 
specified by the manufacturer. The pressure monitor must meet the 
requirements in Table 13 of this subpart.

[[Page 23861]]

    (e) Combustion zone operating limits. The owner or operator shall 
operate the flare to maintain the net heating value of flare combustion 
zone gas (NHVcz) at or above the applicable limits in 
paragraphs (e)(1) and (2) of this section determined on a 15-minute 
block period basis when regulated material is routed to the flare for 
at least 15-minutes. The owner or operator shall monitor and calculate 
NHVcz as specified in paragraph (m) of this section.
    (1) For all flares other than pressure-assisted flares, 270 British 
thermal units per standard cubic feet (Btu/scf).
    (2) Beginning on April 4, 2024, for each pressure-assisted flare, 
800 Btu/scf.
* * * * *
    (l) * * *
    (5) When a continuous monitoring system is used as provided in 
paragraph (j)(1) or (3) of this section and, if applicable, paragraph 
(j)(4) of this section, the owner or operator of a flare other than a 
pressure-assisted flare may elect to determine the 15-minute block 
average NHVvg using either the calculation methods in 
paragraph (l)(5)(i) of this section or the calculation methods in 
paragraph (l)(5)(ii) of this section. The owner or operator may choose 
to comply using the calculation methods in paragraph (l)(5)(i) of this 
section for some non-pressure-assisted flares at the petroleum refinery 
and comply using the calculation methods (l)(5)(ii) of this section for 
other flares. However, for each non-pressure-assisted flare, the owner 
or operator must elect one calculation method that will apply at all 
times, and use that method for all continuously monitored flare vent 
streams associated with that flare. If the owner or operator intends to 
change the calculation method that applies to a flare, the owner or 
operator must notify the Administrator 30 days in advance of such a 
change. For pressure-assisted flares, beginning on April 4, 2024, the 
owner or operator must use the calculation method in paragraph 
(l)(5)(ii) of this section.
* * * * *
    (o) * * *
    (4) * * *
    (iv) Prior to June 3, 2024, you may conduct a single root cause 
analysis and corrective action analysis for a single event that causes 
two or more flares to have a flow event meeting the criteria in 
paragraph (o)(3)(i) or (ii) of this section, regardless of the 
configuration of the flares, if the root cause is reasonably expected 
to be a force majeure event, as defined in this subpart.
* * * * *
    (6) The owner or operator shall determine the total number of 
events for which a root cause and corrective action analyses was 
required during the calendar year for each affected flare separately 
for events meeting the criteria in paragraph (o)(3)(i) of this section 
and those meeting the criteria in paragraph (o)(3)(ii) of this section. 
For the purpose of this requirement, a single root cause analysis 
conducted for an event that met both of the criteria in paragraphs 
(o)(3)(i) and (ii) of this section would be counted as an event under 
each of the separate criteria counts for that flare. Additionally, if a 
single root cause analysis was conducted for an event that caused 
multiple flares to meet the criteria in paragraph (o)(3)(i) or (ii) of 
this section, that event would count as an event for each of the flares 
for each criteria in paragraph (o)(3) of this section that was met 
during that event. Prior to June 3, 2024, the owner or operator shall 
also determine the total number of events for which a root cause and 
correct action analyses was required and the analyses concluded that 
the root cause was a force majeure event, as defined in this subpart.
    (7) * * *
    (ii) Prior to June 3, 2024, two visible emissions exceedance events 
meeting the criteria in paragraph (o)(3)(i) of this section that were 
not caused by a force majeure event from a single flare in a 3 calendar 
year period for the same root cause for the same equipment. On and 
after June 3, 2024, two visible emissions exceedance events meeting the 
criteria in paragraph (o)(3)(i) of this section from a single flare in 
a 3 calendar year period for the same root cause for the same 
equipment.
    (iii) Prior to June 3, 2024, two flare tip velocity exceedance 
events meeting the criteria in paragraph (o)(3)(ii) of this section 
that were not caused by a force majeure event from a single flare in a 
3 calendar year period for the same root cause for the same equipment. 
On and after June 3, 2024, two flare tip velocity exceedance events 
meeting the criteria in paragraph (o)(3)(ii) of this section from a 
single flare in a 3 calendar year period for the same root cause for 
the same equipment.
    (iv) Prior to June 3, 2024, three visible emissions exceedance 
events meeting the criteria in paragraph (o)(3)(i) of this section that 
were not caused by a force majeure event from a single flare in a 3 
calendar year period for any reason. On and after June 3, 2024, three 
visible emissions exceedance events meeting the criteria in paragraph 
(o)(3)(i) of this section from a single flare in a 3 calendar year 
period for any reason.
    (v) Prior to June 3, 2024, three flare tip velocity exceedance 
events meeting the criteria in paragraph (o)(3)(ii) of this section 
that were not caused by a force majeure event from a single flare in a 
3 calendar year period for any reason. On and after June 3, 2024, three 
flare tip velocity exceedance events meeting the criteria in paragraph 
(o)(3)(ii) of this section from a single flare in a 3 calendar year 
period for any reason.
* * * * *

0
7. Amend Sec.  63.671 by:
0
a. Revising paragraph (e) introductory text; and
0
b. Adding paragraphs (e)(4) and (f).
    The additions and revision read as follows:


Sec.  63.671  Requirements for flare monitoring systems.

* * * * *
    (e) Additional requirements for gas chromatographs. For monitors 
used to determine compositional analysis for net heating value per 
Sec.  63.670(j)(1) that include a gas chromatograph, the gas 
chromatograph must also meet the requirements of paragraphs (e)(1) 
through (4) of this section.
* * * * *
    (4) Beginning on April 4, 2024, the owner or operator must 
initially determine the average instrument calibration error during the 
Seven (7)-Day Calibration Error Test Period and subsequently perform 
daily calibration and quarterly audits using either the compound-
specific calibration error (CE) method provided in paragraph (i) of 
this section or using the net heating value (NHV) method provided in 
paragraph (ii) of this section.
    (i) The average instrument CE for each calibration compound at any 
calibration concentration must not differ by more than 10 percent from 
the certified cylinder gas value. The CE for each component in the 
calibration blend must be calculated using the following equation:

Where:
[GRAPHIC] [TIFF OMITTED] TR04AP24.000

Where:

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

    (ii) The CE for NHV at any calibration level must not differ by 
more than 10 percent from the certified cylinder gas value. The CE for 
must be calculated using the following equation:
[GRAPHIC] [TIFF OMITTED] TR04AP24.001

Where:

NHVmeasured = Average instrument response (Btu/scf). NHV 
calculations must be based on the individual component properties in 
table 12 of this subpart.

[[Page 23862]]

NHVa = Certified cylinder gas value (Btu/scf).

    (f) Additional requirements for continuous process mass 
spectrometers. Beginning on April 4, 2024, for continuous process mass 
spectrometers used to determine compositional analysis for net heating 
value per Sec.  63.670(j)(1) without the use of gas chromatography, the 
continuous process mass spectrometer must also meet the requirements of 
paragraphs (f)(1) through (7) of this section.
    (1) You must meet the calibration gas requirements in paragraph 
(e)(2) of this section. You may augment the minimum list of calibration 
gas components found in paragraph (e)(2) of this section with compounds 
found during a pre-survey or known to be in the gas through process 
knowledge.
    (2) Calibration gas cylinders (i.e., low-, mid-, and high-levels) 
must be certified to an accuracy of 2 percent and traceable to National 
Institute of Standards and Technology (NIST) standards.
    (3) For unknown gas components that have similar analytical mass 
fragments to calibration compounds, you may report the unknowns as an 
increase in the overlapped calibration gas compound. For unknown 
compounds that produce mass fragments that do not overlap calibration 
compounds, you may use the response factor for the nearest molecular 
weight hydrocarbon in the calibration mix to quantify the unknown 
component's net heating value of flare vent gas (NHVvg).
    (4) You may use the response factor for n-pentane to quantify any 
unknown components detected with a higher molecular weight than n-
pentane.
    (5) You must perform an initial calibration to identify mass 
fragment overlap and response factors for the target compounds.
    (6) You must meet applicable requirements in Table 13 of this 
subpart for Net Heating Value by Mass Spectrometer.
    (7) The owner or operator must estimate the instrument calibration 
error in accordance with paragraph (e)(4) of this section.

0
8. Amend appendix to subpart CC of part 63 by revising table 13 to read 
as follows:

Appendix to Subpart CC of Part 63--Tables

* * * * *

     Table 13--Calibration and Quality Control Requirements for CPMS
------------------------------------------------------------------------
                                Minimum accuracy         Calibration
          Parameter               requirements          requirements
------------------------------------------------------------------------
Temperature.................  1         Conduct calibration
                               percent over the      checks at least
                               normal range of       annually; conduct
                               temperature           calibration checks
                               measured, expressed   following any
                               in degrees Celsius    period of more than
                               (C), or 2.8 degrees   24 hours throughout
                               C, whichever is       which the
                               greater.              temperature
                                                     exceeded the
                                                     manufacturer's
                                                     specified maximum
                                                     rated temperature
                                                     or install a new
                                                     temperature sensor.
                                                    At least quarterly,
                                                     inspect all
                                                     components for
                                                     integrity and all
                                                     electrical
                                                     connections for
                                                     continuity,
                                                     oxidation, and
                                                     galvanic corrosion,
                                                     unless the CPMS has
                                                     a redundant
                                                     temperature sensor.
                                                    Record the results
                                                     of each calibration
                                                     check and
                                                     inspection.
                                                    Locate the
                                                     temperature sensor
                                                     in a position that
                                                     provides a
                                                     representative
                                                     temperature; shield
                                                     the temperature
                                                     sensor system from
                                                     electromagnetic
                                                     interference and
                                                     chemical
                                                     contaminants.
Flow Rate for All Flows       5         Conduct a flow
 Other Than Flare Vent Gas.    percent over the      sensor calibration
                               normal range of       check at least
                               flow measured or      biennially (every
                               1.9 liters per        two years); conduct
                               minute (0.5 gallons   a calibration check
                               per minute),          following any
                               whichever is          period of more than
                               greater, for liquid   24 hours throughout
                               flow.                 which the flow rate
                                                     exceeded the
                                                     manufacturer's
                                                     specified maximum
                                                     rated flow rate or
                                                     install a new flow
                                                     sensor.
                              5         At least quarterly,
                               percent over the      inspect all
                               normal range of       components for
                               flow measured or      leakage, unless the
                               280 liters per        CPMS has a
                               minute (10 cubic      redundant flow
                               feet per minute),     sensor.
                               whichever is
                               greater, for gas
                               flow.
                              5         Record the results
                               percent over the      of each calibration
                               normal range          check and
                               measured for mass     inspection.
                               flow.
                                                    Locate the flow
                                                     sensor(s) and other
                                                     necessary equipment
                                                     (such as
                                                     straightening
                                                     vanes) in a
                                                     position that
                                                     provides
                                                     representative
                                                     flow; reduce
                                                     swirling flow or
                                                     abnormal velocity
                                                     distributions due
                                                     to upstream and
                                                     downstream
                                                     disturbances.
Flare Vent Gas Flow Rate....  20        Conduct a flow
                               percent of flow       sensor calibration
                               rate at velocities    check at least
                               ranging from 0.03     biennially (every
                               to 0.3 meters per     two years); conduct
                               second (0.1 to 1      a calibration check
                               feet per second).     following any
                                                     period of more than
                                                     24 hours throughout
                                                     which the flow rate
                                                     exceeded the
                                                     manufacturer's
                                                     specified maximum
                                                     rated flow rate or
                                                     install a new flow
                                                     sensor.
                              5         At least quarterly,
                               percent of flow       inspect all
                               rate at velocities    components for
                               greater than 0.3      leakage, unless the
                               meters per second     CPMS has a
                               (1 feet per second).  redundant flow
                                                     sensor.
                                                    Record the results
                                                     of each calibration
                                                     check and
                                                     inspection.
                                                    Locate the flow
                                                     sensor(s) and other
                                                     necessary equipment
                                                     (such as
                                                     straightening
                                                     vanes) in a
                                                     position that
                                                     provides
                                                     representative
                                                     flow; reduce
                                                     swirling flow or
                                                     abnormal velocity
                                                     distributions due
                                                     to upstream and
                                                     downstream
                                                     disturbances.

[[Page 23863]]

 
Pressure....................  5         Review pressure
                               percent over the      sensor readings at
                               normal operating      least once a week
                               range or 0.12         for straightline
                               kilopascals (0.5      (unchanging)
                               inches of water       pressure and
                               column), whichever    perform corrective
                               is greater.           action to ensure
                                                     proper pressure
                                                     sensor operation if
                                                     blockage is
                                                     indicated.
                                                    Using an instrument
                                                     recommended by the
                                                     sensor's
                                                     manufacturer, check
                                                     gauge calibration
                                                     and transducer
                                                     calibration
                                                     annually; conduct
                                                     calibration checks
                                                     following any
                                                     period of more than
                                                     24 hours throughout
                                                     which the pressure
                                                     exceeded the
                                                     manufacturer's
                                                     specified maximum
                                                     rated pressure or
                                                     install a new
                                                     pressure sensor.
                                                    At least quarterly,
                                                     inspect all
                                                     components for
                                                     integrity, all
                                                     electrical
                                                     connections for
                                                     continuity, and all
                                                     mechanical
                                                     connections for
                                                     leakage, unless the
                                                     CPMS has a
                                                     redundant pressure
                                                     sensor.
                                                    Record the results
                                                     of each calibration
                                                     check and
                                                     inspection.
                                                    Locate the pressure
                                                     sensor(s) in a
                                                     position that
                                                     provides a
                                                     representative
                                                     measurement of the
                                                     pressure and
                                                     minimizes or
                                                     eliminates
                                                     pulsating pressure,
                                                     vibration, and
                                                     internal and
                                                     external corrosion.
Net Heating Value by          2         Specify calibration
 Calorimeter.                  percent of span.      requirements in
                                                     your site specific
                                                     CPMS monitoring
                                                     plan. Calibration
                                                     requirements should
                                                     follow
                                                     manufacturer's
                                                     recommendations at
                                                     a minimum.
                                                    Temperature control
                                                     (heated and/or
                                                     cooled as
                                                     necessary) the
                                                     sampling system to
                                                     ensure proper year-
                                                     round operation.
                                                    Where feasible,
                                                     select a sampling
                                                     location at least
                                                     two equivalent
                                                     diameters
                                                     downstream from and
                                                     0.5 equivalent
                                                     diameters upstream
                                                     from the nearest
                                                     disturbance. Select
                                                     the sampling
                                                     location at least
                                                     two equivalent duct
                                                     diameters from the
                                                     nearest control
                                                     device, point of
                                                     pollutant
                                                     generation, air in-
                                                     leakages, or other
                                                     point at which a
                                                     change in the
                                                     pollutant
                                                     concentration or
                                                     emission rate
                                                     occurs.
Net Heating Value by Gas      As specified in       Follow the procedure
 Chromatograph.                Performance           in Performance
                               Specification 9 of    Specification 9 of
                               40 CFR part 60,       40 CFR part 60,
                               appendix B.           appendix B, except
                                                     that a single daily
                                                     mid-level
                                                     calibration check
                                                     can be used (rather
                                                     than triplicate
                                                     analysis), the
                                                     multi-point
                                                     calibration can be
                                                     conducted quarterly
                                                     (rather than
                                                     monthly), and the
                                                     sampling line
                                                     temperature must be
                                                     maintained at a
                                                     minimum temperature
                                                     of 60 [deg]C
                                                     (rather than 120
                                                     [deg]C).
Net Heating Value by Mass     As specified in       Follow the procedure
 Spectrometer.                 Performance           in Performance
                               Specifications 9 of   Specification 9 of
                               40 CFR part 60,       40 CFR part 60,
                               appendix B.           appendix B,
                                                     including
                                                     performing an
                                                     initial multi-point
                                                     calibration check
                                                     at three
                                                     concentrations
                                                     following the
                                                     procedure in
                                                     section 10.1 of
                                                     Performance
                                                     Specification 9,
                                                     except that the
                                                     multi-point
                                                     calibration can be
                                                     conducted quarterly
                                                     (rather than
                                                     monthly), and the
                                                     sampling line
                                                     temperature must be
                                                     maintained at a
                                                     minimum temperature
                                                     of 60 [deg]C
                                                     (rather than 120
                                                     [deg]C).
Hydrogen analyzer...........  2         Specify calibration
                               percent over the      requirements in
                               concentration         your site specific
                               measured or 0.1       CPMS monitoring
                               volume percent,       plan. Calibration
                               whichever is          requirements should
                               greater.              follow
                                                     manufacturer's
                                                     recommendations at
                                                     a minimum.
                                                    Where feasible,
                                                     select the sampling
                                                     location at least
                                                     two equivalent duct
                                                     diameters from the
                                                     nearest control
                                                     device, point of
                                                     pollutant
                                                     generation, air in-
                                                     leakages, or other
                                                     point at which a
                                                     change in the
                                                     pollutant
                                                     concentration
                                                     occurs.
------------------------------------------------------------------------


[[Page 23864]]

Subpart YY--National Emission Standards for Hazardous Air 
Pollutants Air Pollutants for Source Categories: Generic Maximum 
Achievable Control Technology Standards

0
9. Amend Sec.  63.1100 by revising paragraphs (b) and (g)(7)(iii) to 
read as follows:


Sec.  63.1100  Applicability.

* * * * *
    (b) Subpart A requirements. The following provisions of subpart A 
of this part (General Provisions), Sec. Sec.  63.1 through 63.5, and 
Sec. Sec.  63.12 through 63.15, apply to owners or operators of 
affected sources subject to this subpart. For sources that reclassify 
from major source to area source status, the applicable provisions of 
Sec.  63.9(j) and (k) apply. Beginning no later than the compliance 
dates specified in Sec.  63.1102(c), for ethylene production affected 
sources, Sec. Sec.  63.7(a)(4), (c), (e)(4), and (g)(2), Sec.  63.9(k), 
and 63.10(b)(2)(vi) also apply.
* * * * *
    (g) * * *
    (7) * * *
    (iii) Beginning no later than the compliance dates specified in 
Sec.  63.1102(c), flares subject to the requirements in 40 CFR part 63, 
subpart CC and used as a control device for an emission point subject 
to the requirements in Table 7 to Sec.  63.1103(e) are only required to 
comply with the flare requirements in 40 CFR part 63, subpart CC.

0
10. Amend Sec.  63.1102 by revising paragraphs (c)(11), (d)(2)(ii), and 
(e)(2)(iii) to read as follows:


Sec.  63.1102  Compliance schedule.

* * * * *
    (c) * * *
    (11) The requirements in Sec.  63.1108(a)(4), (b)(1)(ii), (b)(2), 
and (b)(4)(ii)(B).
* * * * *
    (d) * * *
    (2) * * *
    (ii) The compliance requirements specified in Sec.  63.1108(a)(4), 
(b)(1)(ii), (b)(2), and (b)(4)(ii)(B).
* * * * *
    (e) * * *
    (2) * * *
    (iii) The compliance requirements specified in Sec.  63.1108(a)(4), 
(b)(1)(ii), (b)(2), and (b)(4)(ii)(B).
* * * * *

0
11. Amend Sec.  63.1103 by:
0
a. Revising paragraphs (e)(4)(iii), (e)(4)(vii)(B), (e)(5)(i)(A), 
(e)(5)(i)(B), (e)(5)(ii), and (e)(7)(i);
0
b. Removing paragraphs (e)(7)(i)(A) and (e)(7)(i)(B);
0
c. Revising paragraphs (e)(8)(i) and (e)(10) introductory text; and
0
d. Adding paragraph (e)(10)(iv).
    The addition and revisions read as follows:


Sec.  63.1103  Source category-specific applicability, definitions, and 
requirements.

* * * * *
    (e) * * *
    (4) * * *
    (iii) Instead of complying with Sec.  63.670(o)(2)(iii) of subpart 
CC, if required to develop a flare management plan and submit it to the 
Administrator, then the owner or operator must also submit all versions 
of the plan in portable document format (PDF) to the EPA following the 
procedure specified in Sec.  63.9(k), except any medium submitted 
through U.S. mail must be sent to the attention of the Ethylene 
Production Sector Lead.
* * * * *
    (vii) * * *
    (B) The owner or operator must comply with the NHVcz requirements 
in Sec.  63.670(e)(2) of subpart CC;
* * * * *
    (5) * * *
    (i) * * *
    (A) The concentration of the vapor in the equipment served by the 
maintenance vent is less than 10 percent of its lower explosive limit 
(LEL).
    (B) If there is no ability to measure the concentration of the 
vapor in the equipment based on the design of the equipment, the 
pressure in the equipment served by the maintenance vent is reduced to 
5 pounds per square inch gauge (psig) or less. Upon opening the 
maintenance vent, active purging of the equipment cannot be used until 
the concentration of the vapors in the maintenance vent (or inside the 
equipment if the maintenance is a hatch or similar type of opening) is 
less than 10 percent of its LEL.
* * * * *
    (ii) Except for maintenance vents complying with the alternative in 
paragraph (e)(5)(i)(C) of this section, the owner or operator must 
determine the concentration of the vapor or, if applicable, equipment 
pressure using process instrumentation or portable measurement devices 
and follow procedures for calibration and maintenance according to 
manufacturer's specifications.
* * * * *
    (7) * * *
    (i) During normal operations, conduct daily inspections of the 
firebox burners and repair all burners that are impinging on the 
radiant tube(s) as soon as practical, but not later than 1 calendar day 
after the flame impingement is found. The owner or operator may delay 
burner repair beyond 1 calendar day provided the repair cannot be 
completed during normal operations, the burner cannot be shutdown 
without significantly impacting the furnace heat distribution and 
firing rate, and action is taken to reduce flame impingement as much as 
possible during continued operation. If a delay of repair is required 
to fully resolve burner flame impingement, repair must be completed 
following the next planned decoking operation (and before returning the 
ethylene cracking furnace back to normal operations) or during the next 
ethylene cracking furnace complete shutdown (when the ethylene cracking 
furnace firebox is taken completely offline), whichever is earlier. An 
inspection may include, but is not limited to: visual inspection of the 
radiant tube(s) for localized bright spots (this may be confirmed with 
a temperature gun), use of luminescent powders injected into the burner 
to illuminate the flame pattern, or identifying continued localized 
coke buildup that causes short runtimes between decoking cycles. A 
repair may include, but is not limited to: Taking the burner out of 
service, replacing the burner, adjusting the alignment of the burner, 
adjusting burner configuration, making burner air corrections, 
repairing a malfunction of the fuel liquid removal equipment, or adding 
insulation around the radiant tube(s).
* * * * *
    (8) * * *
    (i) Prior to decoking operation, inspect the applicable ethylene 
cracking furnace isolation valve(s) to confirm that the radiant tube(s) 
being decoked is completely isolated from the ethylene production 
process so that no emissions generated from decoking operations are 
sent to the ethylene production process. If poor isolation is 
identified, then the owner or operator must rectify the isolation issue 
prior to continuing decoking operations to prevent leaks into the 
ethylene production process, unless the owner or operator determines 
that damage to the radiant tube(s) or ethylene cracking furnace could 
occur if the repair was attempted prior to completing a decoking 
operation and/or prior to the ethylene cracking furnace being shut 
down.
* * * * *
    (10) Storage vessel degassing. Beginning no later than the 
compliance dates specified in Sec.  63.1102(c), for each storage vessel 
subject to paragraph (b) or (c) of Table 7 to Sec.  63.1103(e), the 
owner or operator must comply with

[[Page 23865]]

paragraphs (e)(10)(i) through (iv) of this section during storage 
vessel shutdown operations (i.e., emptying and degassing of a storage 
vessel) until the vapor space concentration in the storage vessel is 
less than 10 percent of the LEL. The owner or operator must determine 
the concentration using process instrumentation or portable measurement 
devices and follow procedures for calibration and maintenance according 
to manufacturer's specifications.
* * * * *
    (iv) For floating roof storage vessels, the storage vessel may be 
opened to set up equipment (e.g., making connections to a temporary 
control device) for the shutdown operations but must not be actively 
degassed during this time period.
* * * * *

0
12. Amend Sec.  63.1107 by revising paragraphs (h)(3)(iv), (h)(3)(v)(B) 
and (C), (h)(6) introductory text, and (h)(6)(ii) to read as follows:


Sec.  63.1107  Equipment leaks.

* * * * *
    (h) * * *
    (3) * * *
    (iv) The owner or operator must determine the total number of 
release events that occurred during the calendar year for each affected 
pressure relief device separately. Prior to June 3, 2024, the owner or 
operator must also determine the total number of release events for 
each pressure relief device for which the root cause analysis concluded 
that the root cause was a force majeure event, as defined in Sec.  
63.1103(e)(2).
    (v) * * *
    (B) Prior to June 3, 2024, a second release event not including 
force majeure events from a single pressure relief device in a 3-
calendar year period for the same root cause for the same equipment. On 
and after June 3, 2024, a second release event from a single pressure 
relief device in a 3-calendar year period for the same root cause for 
the same equipment.
    (C) Prior to June 3, 2024, a third release event not including 
force majeure events from a single pressure relief device in a 3-
calendar year period for any reason. On and after June 3, 2024, a third 
release event from a single pressure relief device in a 3-calendar year 
period for any reason.
* * * * *
    (6) Root cause analysis and corrective action analysis. A root 
cause analysis and corrective action analysis must be completed as soon 
as possible, but no later than 45 days after a release event. Special 
circumstances affecting the number of root cause analyses and/or 
corrective action analyses are provided in paragraphs (h)(6)(i) through 
(iii) of this section.
* * * * *
    (ii) Prior to June 3, 2024, you may conduct a single root cause 
analysis and corrective action analysis for a single emergency event 
that causes two or more pressure relief devices to release, regardless 
of the equipment served, if the root cause is reasonably expected to be 
a force majeure event, as defined in Sec.  63.1103(e)(2).
* * * * *

0
13. Amend Sec.  63.1109 by revising paragraphs (f)(2), (3), and (5), 
and (i)(2) to read as follows:


Sec.  63.1109  Recordkeeping requirements.

* * * * *
    (f) * * *
    (2) If complying with the requirements of Sec.  63.1103(e)(5)(i)(A) 
and the concentration of the vapor at the time of the vessel opening 
exceeds 10 percent of its LEL, records that identify the maintenance 
vent, the process units or equipment associated with the maintenance 
vent, the date of maintenance vent opening, and the concentration of 
the vapor at the time of the vessel opening.
    (3) If complying with the requirements of Sec.  63.1103(e)(5)(i)(B) 
and either the vessel pressure at the time of the vessel opening 
exceeds 5 psig or the concentration of the vapor at the time of the 
active purging was initiated exceeds 10 percent of its LEL, records 
that identify the maintenance vent, the process units or equipment 
associated with the maintenance vent, the date of maintenance vent 
opening, the pressure of the vessel or equipment at the time of 
discharge to the atmosphere and, if applicable, the concentration of 
the vapors in the equipment when active purging was initiated.
* * * * *
    (5) If complying with the requirements of Sec.  
63.1103(e)(5)(i)(D), identification of the maintenance vent, the 
process units or equipment associated with the maintenance vent, 
records documenting actions taken to comply with other applicable 
alternatives and why utilization of this alternative was required, the 
date of maintenance vent opening, the equipment pressure and 
concentration of the vapors in the equipment at the time of discharge, 
an indication of whether active purging was performed and the pressure 
of the equipment during the installation or removal of the blind if 
active purging was used, the duration the maintenance vent was open 
during the blind installation or removal process, and records used to 
estimate the total quantity of VOC in the equipment at the time the 
maintenance vent was opened to the atmosphere for each applicable 
maintenance vent opening.
* * * * *
    (i) * * *
    (2) Records of the number of releases during each calendar year 
and, prior to June 3, 2024, the number of those releases for which the 
root cause was determined to be a force majeure event. Keep these 
records for the current calendar year and the past five calendar years.
* * * * *

0
14. Amend Sec.  63.1110 by revising paragraphs (a)(10), (e)(4)(iii), 
(e)(4)(iv)(A) and (B), (e)(5)(iii), and (e)(8)(iii) to read as follows:


Sec.  63.1110  Reporting requirements.

    (a) * * *
    (10)(i) Beginning no later than the compliance dates specified in 
Sec.  63.1102(c) for ethylene production affected sources, specified in 
Sec.  63.1102(d) for cyanide chemicals manufacturing affected sources, 
and specified in Sec.  63.1102(e) for carbon black production affected 
sources, within 60 days after the date of completing each performance 
test required by this subpart or applicability assessment required by 
Sec.  63.1103(f)(3)(iv), the owner or operator must submit the results 
of the performance test or applicability assessment following the 
procedures specified in Sec.  63.9(k). Data collected using test 
methods supported by the EPA's Electronic Reporting Tool (ERT) as 
listed on the EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of 
the test must be submitted in a file format generated through the use 
of the EPA's ERT. Alternatively, you may submit an electronic file 
consistent with the extensible markup language (XML) schema listed on 
the EPA's ERT website. Data collected using test methods that are not 
supported by the EPA's ERT as listed on the EPA's ERT website at the 
time of the test must be included as an attachment in the ERT or 
alternate electronic file.
    (ii) Beginning no later than the compliance dates specified in 
Sec.  63.1102(c) through (e), the owner or operator must submit all 
subsequent Notification of Compliance Status reports required under 
paragraph (a)(4) of this section in portable document format (PDF) 
format to the EPA

[[Page 23866]]

following the procedure specified in Sec.  63.9(k). All subsequent 
Periodic Reports required under paragraph (a)(5) of this section must 
be submitted to the EPA via CEDRI using the appropriate electronic 
report template on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for this subpart and following the 
procedure specified in Sec.  63.9(k) beginning no later than the 
compliance dates specified in Sec.  63.1102(c) through (e) or once the 
report template has been available on the CEDRI website for 1 year, 
whichever date is later. The date report templates become available 
will be listed on the CEDRI website. Unless the Administrator or 
delegated State agency or other authority has approved a different 
schedule for submission of reports under Sec.  63.9(i) and Sec.  
63.10(a) of subpart A, the report must be submitted by the deadline 
specified in this subpart, regardless of the method in which the report 
is submitted. Any medium submitted through mail under Sec.  63.9(k) for 
a Notification of Compliance Status report or Periodic Report must be 
sent to the attention of the Ethylene Production Sector Lead, Cyanide 
Chemicals Manufacturing Sector Lead, or Carbon Black Production Sector 
Lead, as appropriate.
    (iii) Beginning no later than the compliance date specified in 
Sec.  63.1102(c) or once the report template for this subpart has been 
available on the CEDRI website for six months, whichever date is later, 
the items in Sec.  63.1110(e)(4)(iv) and Sec.  63.1110(e)(8)(iii) must 
be submitted to the EPA via CEDRI as specified in Sec.  63.9(k) using 
the appropriate electronic report template on the CEDRI website for 
reporting that information. The report submitted to CEDRI must also 
contain company identifier information (including the company name and 
address) and the beginning and ending dates of the time period covered 
by the report. Once you begin submitting Periodic Reports to CEDRI in 
accordance with paragraph (a)(10)(ii) of this section, the items in 
Sec.  63.1110(e)(4)(iv) and Sec.  63.1110(e)(8)(iii) must be included 
in those Periodic Reports instead of submitting the information using 
the separate template.
* * * * *
    (e) * * *
    (4) * * *
    (iii) The periods specified in Sec.  63.1109(e)(6). Indicate the 
date and start time for the period, and the net heating value operating 
parameter(s) determined following the methods in Sec.  63.670(k) 
through (n) of subpart CC as applicable.
    (iv) * * *
    (A) Flare identification name or number and the start and stop time 
and date of the flaring event.
    (B) The length of time (in minutes) that emissions were visible 
from the flare during the event.
* * * * *
    (5) * * *
    (iii) The LEL, vessel pressure, or mass of VOC in the equipment, as 
applicable, at the start of atmospheric venting. If the 5 psig vessel 
pressure option in Sec.  63.1103(e)(5)(i)(B) was used and active 
purging was initiated while the concentration of the vapor was 10 
percent or greater of its LEL, also include the concentration of the 
vapors at the time active purging was initiated.
* * * * *
    (8) * * *
    (iii) For pressure relief devices in organic HAP service subject to 
Sec.  63.1107(h)(3), report each pressure release to the atmosphere, 
including pressure relief device identification name or number; start 
date and start time and duration (in hours) of the pressure release; an 
estimate (in pounds) of the mass quantity of each organic HAP released; 
the results of any root cause analysis and corrective action analysis 
completed during the reporting period, including the corrective actions 
implemented during the reporting period; and, if applicable, the 
implementation schedule for planned corrective actions to be 
implemented subsequent to the reporting period.
* * * * *

Subpart EEEE--National Emission Standards for Hazardous Air 
Pollutants: Organic Liquids Distribution (Non-Gasoline)

0
15. Amend Sec.  63.2346 by:
0
a. Revising paragraph (a)(6) introductory text;
0
b. Adding paragraph (a)(6)(iv); and
0
c. Revising paragraph (e).
    The addition and revisions read as follows:


Sec.  63.2346  What emission limitations, operating limits, and work 
practice standards must I meet?

    (a) * * *
    (6) Beginning no later than the compliance dates specified in Sec.  
63.2342(e), tank emissions during storage tank shutdown operations 
(i.e., emptying and degassing of a storage tank) for each storage tank 
at an affected source storing organic liquids that meets the tank 
capacity and liquid vapor pressure criteria for control in items 2 
through 6 of Table 2 to this subpart, or items 1 through 3 of Table 2b 
to this subpart, you must comply with paragraphs (a)(6)(i) through (iv) 
of this section during tank emptying and degassing until the vapor 
space concentration in the tank is less than 10 percent of the lower 
explosive limit (LEL). The owner or operator must determine the 
concentration using process instrumentation or portable measurement 
devices and follow procedures for calibration and maintenance according 
to manufacturer's specifications.
* * * * *
    (iv) For floating roof storage tanks, the storage tank may be 
opened to set up equipment (e.g., making connections to a temporary 
control device) for the shutdown operations but must not be actively 
degassed during this time period.
* * * * *
    (e) Operating limits. For each high throughput transfer rack, you 
must meet each operating limit in Table 3 to this subpart for each 
control device used to comply with the provisions of this subpart 
whenever emissions from the loading of organic liquids are routed to 
the control device. Except as specified in paragraph (k) of this 
section, for each storage tank and low throughput transfer rack, you 
must comply with paragraph (l) of this section and the requirements for 
monitored parameters as specified in subpart SS of this part, for 
storage tanks and, during the loading of organic liquids, for low 
throughput transfer racks, respectively. Alternatively, you may comply 
with the operating limits in table 3 to this subpart.
* * * * *

0
16. Amend Sec.  63.2378 by revising and republishing paragraph (e) to 
read as follows:


Sec.  63.2378  How do I demonstrate continuous compliance with the 
emission limitations, operating limits, and work practice standards?

* * * * *
    (e) Beginning no later than the compliance dates specified in Sec.  
63.2342(e), paragraphs (b) through (d) of this section no longer apply. 
Instead, you must be in compliance with each emission limitation, 
operating limit, and work practice standard specified in paragraph (a) 
of this section at all times, except during periods of nonoperation of 
the affected source (or specific portion thereof) resulting in 
cessation of the emissions to which this subpart applies and must 
comply with the requirements specified in paragraphs

[[Page 23867]]

(e)(1) through (4) of this section, as applicable. Equipment subject to 
the work practice standards for equipment leak components in Table 4 to 
this subpart, item 4 are not subject to this paragraph (e).
    (1) Except as specified in paragraphs (e)(3) and (4) of this 
section, the use of a bypass line at any time on a closed vent system 
to divert a vent stream to the atmosphere or to a control device not 
meeting the requirements specified in paragraph (a) of this section is 
an emissions standards deviation.
    (2) If you are subject to the bypass monitoring requirements of 
Sec.  63.983(a)(3), then you must continue to comply with the 
requirements in Sec.  63.983(a)(3) and the recordkeeping and reporting 
requirements in Sec. Sec.  63.998(d)(1)(ii) and 63.999(c)(2), in 
addition to Sec.  63.2346(l), the recordkeeping requirements specified 
in Sec.  63.2390(g), and the reporting requirements specified in Sec.  
63.2386(c)(12).
    (3) Periods of planned routine maintenance of a control device used 
to control storage tank breathing loss emissions, during which the 
control device does not meet the emission limits in Table 2 or 2b to 
this subpart, must not exceed 240 hours per year. The level of material 
in the storage tank shall not be increased during periods that the 
closed-vent system or control device is bypassed to perform planned 
routine maintenance.
    (4) If you elect to route emissions from storage tanks to a fuel 
gas system or to a process, as allowed by Sec.  63.982(d), to comply 
with the emission limits in Table 2 or 2b to this subpart, the total 
aggregate amount of time during which the breathing loss emissions 
bypass the fuel gas system or process during the calendar year without 
being routed to a control device, for all reasons (except product 
changeovers of flexible operation units and periods when a storage tank 
has been emptied and degassed), must not exceed 240 hours. The level of 
material in the storage tank shall not be increased during periods that 
the fuel gas system or process is bypassed.
* * * * *

0
17. Amend Sec.  63.2382 by revising paragraph (d)(3) to read as 
follows:


Sec.  63.2382  What notifications must I submit and when and what 
information should be submitted?

* * * * *
    (d) * * *
    (3) Submitting Notification of Compliance Status. Beginning no 
later than the compliance dates specified in Sec.  63.2342(e), you must 
submit all subsequent Notification of Compliance Status reports in 
portable document format (PDF) format to the EPA following the 
procedure specified in Sec.  63.9(k), except any medium submitted 
through mail must be sent to the attention of the Organic Liquids 
Distribution Sector Lead.

0
18. Amend Sec.  63.2386 by:
0
a. Revising paragraphs (f), (g), and (h); and
0
b. Removing paragraphs (i) and (j).
    The revisions read as follows:


Sec.  63.2386  What reports must I submit and when and what information 
is to be submitted in each?

* * * * *
    (f) Beginning no later than the compliance dates specified in Sec.  
63.2342(e), you must submit all Compliance reports to the EPA following 
the procedure specified in Sec.  63.9(k), except any medium submitted 
through U.S. mail must be sent to the attention of the Organic Liquids 
Distribution Sector Lead. You must use the appropriate electronic 
report template on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for this subpart. The date report 
templates become available will be listed on the CEDRI website. Unless 
the Administrator or delegated state agency or other authority has 
approved a different schedule for submission of reports under 
Sec. Sec.  63.9(i) and 63.10(a), the report must be submitted by the 
deadline specified in this subpart, regardless of the method in which 
the report is submitted.
    (g) Beginning no later than the compliance dates specified in Sec.  
63.2342(e), you must start submitting performance test reports in 
accordance with this paragraph. Unless otherwise specified in this 
subpart, within 60 days after the date of completing each performance 
test required by this subpart, you must submit the results of the 
performance test following the procedures specified in Sec.  63.9(k). 
Data collected using test methods supported by the EPA's Electronic 
Reporting Tool (ERT) as listed on the EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test must be submitted in a file format 
generated through the use of the EPA's ERT. Alternatively, you may 
submit an electronic file consistent with the XML schema listed on the 
EPA's ERT website. Data collected using test methods that are not 
supported by the EPA's ERT as listed on the EPA's ERT website at the 
time of the test must be included as an attachment in the ERT or 
alternate electronic file.
    (h) Beginning no later than the compliance dates specified in Sec.  
63.2342(e), you must start submitting performance evaluation reports in 
accordance with this paragraph. Unless otherwise specified in this 
subpart, within 60 days after the date of completing each CEMS 
performance evaluation (as defined in Sec.  63.2) that includes a 
relative accuracy test audit (RATA), you must submit the results of the 
performance evaluation following the procedures specified in Sec.  
63.9(k). The results of performance evaluations of CEMS measuring RATA 
pollutants that are supported by the EPA's ERT as listed on the EPA's 
ERT website at the time of the evaluation must be submitted in a file 
format generated through the use of the EPA's ERT. Alternatively, you 
may submit an electronic file consistent with the XML schema listed on 
the EPA's ERT website. The results of performance evaluations of CEMS 
measuring RATA pollutants that are not supported by the EPA's ERT as 
listed on the EPA's ERT website at the time of the evaluation must be 
included as an attachment in the ERT or alternate electronic file.


Sec.  63.2406  [Amended]

0
19. Amend Sec.  63.2406 by removing the definition of ``Force majeure 
event''.

0
20. Amend table 12 to subpart EEEE of part 63 by:
0
a. Adding the entry ``63.7(a)(4)'' in numerical order; and
0
b. Revising the entry ``63.9(k)''.
    The addition and revision read as follows:

Table 12 to Subpart EEEE of Part 63--Applicability of General 
Provisions to Subpart EEEE

* * * * *

[[Page 23868]]



----------------------------------------------------------------------------------------------------------------
               Citation                        Subject             Brief description     Applies to subpart EEEE
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Sec.   63.7(a)(4)....................  Force Majeure--          Requirements to claim a  Yes.
                                        Performance Testing      delay in conducting a
                                        Delay.                   performance test due
                                                                 to force majeure.
 
                                                  * * * * * * *
Sec.   63.9(k).......................  Electronic reporting     Procedure to report      Yes.
                                        procedures.              electronically for
                                                                 notifications and
                                                                 reports.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

Subpart FFFF--National Emission Standards for Hazardous Air 
Pollutants: Miscellaneous Organic Chemical Manufacturing

0
21. Amend Sec.  63.2450 by revising paragraphs (e)(1), (e)(5)(iv), 
(e)(5)(viii)(B), (e)(6)(i), (e)(7) introductory text, (v)(1)(i), 
(v)(1)(ii), and (v)(2) to read as follows:


Sec.  63.2450  What are my general requirements for complying with this 
subpart?

* * * * *
    (e) * * *
    (1) Except when complying with Sec.  63.2485 or paragraph (e)(7) of 
this section, if you reduce organic HAP emissions by venting emissions 
through a closed-vent system to any combination of control devices 
(except a flare) or recovery devices, you must meet the requirements of 
paragraph (e)(4) of this section, and the requirements of Sec.  
63.982(c) and the requirements referenced therein.
* * * * *
    (5) * * *
    (iv) Instead of complying with paragraph (o)(2)(iii) of Sec.  
63.670 of subpart CC, if required to develop a flare management plan 
and submit it to the Administrator, then you must also submit all 
versions of the plan in portable document format (PDF) to the EPA 
following the procedure specified in Sec.  63.9(k), except any medium 
submitted through mail must be sent to the attention of the 
Miscellaneous Organic Chemical Manufacturing Sector Lead.
* * * * *
    (viii) * * *
    (B) You must comply with the NHVcz requirements in paragraph (e)(2) 
of Sec.  63.670 of subpart CC;
* * * * *
    (6) * * *
    (i) If you are subject to the bypass monitoring requirements of 
Sec.  63.148(f) of subpart G, then you must continue to comply with the 
requirements in Sec.  63.148(f) of subpart G and the recordkeeping and 
reporting requirements in Sec. Sec.  63.148(j)(2) and (3) of subpart G, 
and Sec.  63.148(i)(3) of subpart G, in addition to the applicable 
requirements specified in Sec.  63.2485(q), the recordkeeping 
requirements specified in Sec.  63.2525(n), and the reporting 
requirements specified in Sec.  63.2520(e)(12).
* * * * *
    (7) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), if you reduce organic HAP emissions by venting emissions 
through a closed-vent system to an adsorber(s) that cannot be 
regenerated or a regenerative adsorber(s) that is regenerated offsite, 
then you must comply with paragraphs (e)(4) and (6) of this section, 
Sec.  63.2470(c)(3), Sec. Sec.  63.2520(d)(6) and (e)(13), Sec.  
63.2525(o), the requirements in Sec.  63.983 including the requirements 
referenced therein, and you must install a system of two or more 
adsorber units in series and comply with the requirements specified in 
paragraphs (e)(7)(i) through (iii) of this section.
* * * * *
    (v) * * *
    (1) * * *
    (i) The vapor in the equipment served by the maintenance vent has a 
concentration less than 10 percent of its lower explosive limit (LEL) 
and has an outlet concentration less than or equal to 20 ppmv hydrogen 
halide and halogen HAP.
    (ii) If there is no ability to measure the concentration of the 
vapor in the equipment based on the design of the equipment, the 
pressure in the equipment served by the maintenance vent is reduced to 
5 pounds per square inch gauge (psig) or less. Upon opening the 
maintenance vent, active purging of the equipment cannot be used until 
the concentration of the vapors in the maintenance vent (or inside the 
equipment if the maintenance is a hatch or similar type of opening) is 
less than 10 percent of its LEL.
* * * * *
    (2) Except for maintenance vents complying with the alternative in 
paragraph (v)(1)(iii) of this section, you must determine the 
concentration of the vapor or, if applicable, equipment pressure using 
process instrumentation or portable measurement devices and follow 
procedures for calibration and maintenance according to manufacturer's 
specifications.
* * * * *

0
22. Amend Sec.  63.2460 by revising paragraph (c)(9) introductory text 
to read as follows:


Sec.  63.2460  What requirements must I meet for batch process vents?

* * * * *
    (c) * * *
    (9) Requirements for a biofilter. If you use a biofilter to meet 
either the 95-percent reduction requirement or outlet concentration 
requirement specified in Table 2 to this subpart, you must meet the 
requirements specified in paragraphs (c)(9)(i) through (iv) of this 
section.
* * * * *

0
23. Amend Sec.  63.2470 by revising paragraph (f) introductory text and 
adding paragraph (f)(4) to read as follows:


Sec.  63.2470  What requirements must I meet for storage tanks?

* * * * *
    (f) Storage tank degassing. Beginning no later than the compliance 
dates specified in Sec.  63.2445(g), for each storage tank subject to 
item 1 of Table 4 to this subpart, you must comply with paragraphs 
(f)(1) through (4) of this section during storage tank shutdown 
operations (i.e., emptying and degassing of a storage tank) until the 
vapor space concentration in the storage tank is less than 10 percent 
of the LEL. You must determine the concentration using process 
instrumentation or portable measurement devices and follow procedures 
for calibration and maintenance according to manufacturer's 
specifications.
* * * * *

[[Page 23869]]

    (4) For floating roof storage tanks, the storage tank may be opened 
to set up equipment (e.g., making connections to a temporary control 
device) for the shutdown operations but must not be actively degassed 
during this time period.

0
24. Amend Sec.  63.2480 by revising paragraphs (a), (e)(2)(ii), 
(e)(2)(iii), (e)(3)(iv), (e)(3)(v)(B), (e)(3)(v)(C), (e)(6)(ii), 
(f)(18)(iii), (f)(18)(vi), (f)(18)(x), and (f)(18)(xiii) to read as 
follows:


Sec.  63.2480  What requirements must I meet for equipment leaks?

    (a) You must meet each requirement in table 6 to this subpart that 
applies to your equipment leaks, except as specified in paragraphs (b) 
through (f) of this section. For each light liquid pump, pressure 
relief device, and connector in ethylene oxide service as defined in 
Sec.  63.2550(i), you must also meet the applicable requirements 
specified in Sec. Sec.  63.2492 and 63.2493(d) and (e).
* * * * *
    (e) * * *
    (2) * * *
    (ii) If the pressure relief device includes a rupture disk, either 
comply with the requirements in paragraph (e)(2)(i) of this section 
(and do not replace the rupture disk) or install a replacement disk as 
soon as practicable after a pressure release, but no later than 5 
calendar days after the pressure release.
    (iii) If the pressure relief device consists only of a rupture 
disk, install a replacement disk as soon as practicable after a 
pressure release, but no later than 5 calendar days after the pressure 
release. You must not initiate startup of the equipment served by the 
rupture disk until the rupture disc is replaced.
    (3) * * *
    (iv) You must determine the total number of release events that 
occurred during the calendar year for each affected pressure relief 
device separately. Prior to June 3, 2024, you must also determine the 
total number of release events for each pressure relief device for 
which the root cause analysis concluded that the root cause was a force 
majeure event, as defined in Sec.  63.2550.
    (v) * * *
    (B) Prior to June 3, 2024, a second release event not including 
force majeure events from a single pressure relief device in a 3 
calendar year period for the same root cause for the same equipment. On 
and after June 3, 2024, a second release event from a single pressure 
relief device in a 3 calendar year period for the same root cause for 
the same equipment.
    (C) Prior to June 3, 2024, a third release event not including 
force majeure events from a single pressure relief device in a 3 
calendar year period for any reason. On and after June 3, 2024, a third 
release event from a single pressure relief device in a 3 calendar year 
period for any reason.
* * * * *
    (6) * * *
    (ii) Prior to June 3, 2024, you may conduct a single root cause 
analysis and corrective action analysis for a single emergency event 
that causes two or more pressure relief devices to release, regardless 
of the equipment served, if the root cause is reasonably expected to be 
a force majeure event, as defined in Sec.  63.2550.
* * * * *
    (f) * * *
    (18) * * *
    (iii) In Sec.  63.181(b)(3)(i), replace the reference to Sec.  
63.165(a) with Sec.  63.2480(e)(1).
* * * * *
    (vi) The information in Sec.  63.165(a) required to be reported 
under Sec.  63.182(d)(2)(xiv) is now required to be reported under 
Sec.  63.2520(e)(15)(i) through (iii).
* * * * *
    (x) The reference to Sec.  63.1030(c) in Sec.  63.1023(a)(1)(v) no 
longer applies. Instead comply with the Sec.  63.2480(e)(1) and (2).
* * * * *
    (xiii) The information in Sec.  63.1030(b) required to be reported 
under Sec.  63.1039(b)(4) is now required to be reported under Sec.  
63.2520(e)(15)(i) and (ii).
* * * * *

0
25. Amend Sec.  63.2490 by:
0
a. Revising paragraphs (a), (d) introductory text, and (d)(4)(iii) 
introductory text; and
0
b. Adding paragraph (e).
    The addition and revisions read as follows:


Sec.  63.2490  What requirements must I meet for heat exchange systems?

    (a) You must comply with each requirement in Table 10 to this 
subpart that applies to your heat exchange systems, except as specified 
in paragraphs (b) through (e) of this section.
* * * * *
    (d) Unless one or more of the conditions specified in Sec.  
63.104(a)(1), (2), (5), and (6) or paragraph (e) of this section are 
met, beginning no later than the compliance dates specified in Sec.  
63.2445(g), the requirements of Sec.  63.104 as specified in Table 10 
to this subpart and paragraphs (b) and (c) of this section no longer 
apply. Instead, you must monitor the cooling water for the presence of 
total strippable hydrocarbons that indicate a leak according to 
paragraph (d)(1) of this section, and if you detect a leak, then you 
must repair it according to paragraphs (d)(2) and (3) of this section, 
unless repair is delayed according to paragraph (d)(4) of this section. 
At any time before the compliance dates specified in Sec.  63.2445(g), 
you may choose to comply with the requirements in this paragraph (d) in 
lieu of the requirements of Sec.  63.104 as specified in Table 10 to 
this subpart and paragraphs (b) and (c) of this section. The 
requirements in this paragraph (d) do not apply to heat exchange 
systems that have a maximum cooling water flow rate of 10 gallons per 
minute or less.
* * * * *
    (4) * * *
    (iii) The delay of repair action level is a total strippable 
hydrocarbon concentration (as methane) in the stripping gas of 62 ppmv 
or, for heat exchange systems with a recirculation rate of 10,000 
gallons per minute or less, the delay of repair action level is a total 
hydrocarbon mass emissions rate (as methane) of 1.8 kg/hr. The delay of 
repair action level is assessed as described in paragraph 
(d)(4)(iii)(A) or (B) of this section, as applicable.
* * * * *
    (e) If 99 percent by weight or more of the organic compounds that 
could leak into the heat exchange system are water soluble and have a 
Henry's Law Constant less than 5.0E-6 at 25 degrees Celsius 
(atmospheres-cubic meters/mol) and none of the conditions specified in 
Sec.  63.104(a)(1), (2), (5), and (6) are met, beginning no later than 
the compliance dates specified in Sec.  63.2445(g), you may monitor the 
cooling water for leaks according to the requirements in Sec.  
63.104(b) in lieu of using the Modified El Paso Method. If you detect a 
leak according to Sec.  63.104(b), then you must repair it according to 
paragraph (e)(1) of this section, unless repair is delayed according to 
paragraph (e)(2) of this section.
    (1) If a leak is detected using the methods described in paragraph 
(e) of this section, you must repair the leak as soon as practicable, 
but no later than 45 days after identifying the leak, except as 
specified in paragraph (e)(2) of this section. Repair must include re-
monitoring at the monitoring location where the leak was identified to 
verify that the criteria in Sec.  63.104(b)(6) is no longer met. 
Actions that can be taken to

[[Page 23870]]

achieve repair include but are not limited to:
    (i) Physical modifications to the leaking heat exchanger, such as 
welding the leak or replacing a tube;
    (ii) Blocking the leaking tube within the heat exchanger;
    (iii) Changing the pressure so that water flows into the process 
fluid;
    (iv) Replacing the heat exchanger or heat exchanger bundle; or
    (v) Isolating, bypassing, or otherwise removing the leaking heat 
exchanger from service until it is otherwise repaired.
    (2) You may delay repair when the conditions in Sec.  63.104(e) are 
met.

0
26. Amend Sec.  63.2492 by revising paragraph (b) to read as follows:


Sec.  63.2492  How do I determine whether my process vent, storage 
tank, or equipment is in ethylene oxide service?

* * * * *
    (b) For storage tanks, you must determine the concentration of 
ethylene oxide of the fluid stored in the storage tanks by complying 
with the requirements in paragraph (b)(1) or (2) of this section.
    (1) You must measure the concentration of ethylene oxide of the 
fluid stored in the storage tanks using Method 624.1 of 40 CFR part 
136, appendix A, or preparation by Method 5031 and analysis by Method 
8260D (both incorporated by reference, see Sec.  63.14) in the SW-846 
Compendium. In lieu of preparation by SW-846 Method 5031, you may use 
SW-846 Method 5030B (incorporated by reference, see Sec.  63.14), as 
long as: You do not use a preservative in the collected sample; you 
store the sample with minimal headspace as cold as possible and at 
least below 4 degrees C; and you analyze the sample as soon as 
possible, but in no case longer than 7 days from the time the sample 
was collected. If you are collecting a sample from a pressure vessel, 
you must maintain the sample under pressure both during and following 
sampling.
    (2) Unless specified by the Administrator, you may calculate the 
concentration of ethylene oxide of the fluid stored in the storage 
tanks if information specific to the fluid stored is available. 
Information specific to the fluid stored includes concentration data 
from safety data sheets.
* * * * *

0
27. Amend Sec.  63.2493 by revising paragraphs (a)(2)(vi) introductory 
text, (a)(2)(vi)(C), (a)(2)(viii), (b)(2), (b)(4) introductory text, 
(b)(4)(iv), (b)(6), (d)(1)(iii), (d)(2)(iii), (d)(3), (d)(4)(v), and 
(e) introductory text to read as follows:


Sec.  63.2493  What requirements must I meet for process vents, storage 
tanks, or equipment that are in ethylene oxide service?

* * * * *
    (a) * * *
    (2) * * *
    (vi) If you vent emissions through a closed-vent system to a 
scrubber with a reactant tank, then you must establish operating 
parameter limits by monitoring the operating parameters specified in 
paragraphs (a)(2)(vi)(A) through (C) of this section during the 
performance test.
* * * * *
    (C) Temperature of the scrubber liquid entering the scrubber 
column. The temperature may be measured at any point after the heat 
exchanger and prior to entering the top of the scrubber column. 
Determine the average inlet scrubber liquid temperature as the average 
of the test run averages.
* * * * *
    (viii) If you vent emissions through a closed-vent system to a 
control device other than a flare, scrubber with a reactant tank, or 
thermal oxidizer, then you must notify the Administrator of the 
operating parameters that you plan to monitor during the performance 
test prior to establishing operating parameter limits for the control 
device.
* * * * *
    (b) * * *
    (2) If you choose to reduce emissions of ethylene oxide by venting 
emissions through a closed-vent system to a non-flare control device 
that reduces ethylene oxide to less than 1 ppmv as specified in Table 
1, 2, or 4 to this subpart, and you choose to comply with paragraph 
(a)(3)(i) of this section, then continuously monitor the ethylene oxide 
concentration at the exit of the control device using an FTIR CEMS 
meeting the requirements of Performance Specification 15 of 40 CFR part 
60, appendix B, and Sec.  63.2450(j). If you use an FTIR CEMS, you do 
not need to conduct the performance testing required in paragraph 
(b)(3) of this section or the operating parameter monitoring required 
in paragraphs (b)(4) through (6) of this section.
* * * * *
    (4) If you vent emissions through a closed-vent system to a 
scrubber with a reactant tank, then you must comply with Sec.  
63.2450(e)(4) and (6) and the requirements in Sec.  63.983, and you 
must meet the operating parameter limits specified in paragraphs 
(b)(4)(i) through (v) of this section.
* * * * *
    (iv) Maximum temperature of the scrubber liquid entering the 
scrubber column, equal to the average temperature measured during the 
most recent performance test. Compliance with the inlet scrubber liquid 
temperature operating limit must be determined continuously on a 1-hour 
block basis. Use a temperature sensor with a minimum accuracy of 1 percent over the normal range of the temperature measured, 
expressed in degrees Celsius, or 2.8 degrees Celsius, whichever is 
greater.
* * * * *
    (6) If you vent emissions through a closed-vent system to a control 
device other than a flare, scrubber with a reactant tank, or thermal 
oxidizer, then you must comply with Sec.  63.2450(e)(4) and (6) and the 
requirements in Sec.  63.983, and you must monitor the operating 
parameters identified in paragraph (a)(2)(viii) of this section and 
meet the established operating parameter limits to ensure continuous 
compliance. The frequency of monitoring and averaging time will be 
determined based upon the information provided to the Administrator.
* * * * *
    (d) * * *
    (1) * * *
    (iii) When a leak is detected, it must be repaired as soon as 
practicable, but not later than 15 calendar days after it is detected. 
Delay of repair of pumps for which leaks have been detected is allowed 
for pumps that are isolated from the process and that do not remain in 
ethylene oxide service.
    (2) * * *
    (iii) When a leak is detected, it must be repaired as soon as 
practicable, but not later than 15 calendar days after it is detected. 
Delay of repair of connectors for which leaks have been detected is 
allowed for connectors that are isolated from the process and that do 
not remain in ethylene oxide service.
    (3) For each light liquid pump or connector in ethylene oxide 
service that is added to an MCPU, and for each light liquid pump or 
connector in ethylene oxide service that replaces a light liquid pump 
or connector in ethylene oxide service, you must initially monitor for 
leaks within 5 days after initial startup of the equipment.
    (4) * * *
    (v) Replace all references to Sec.  63.2445(g) with Sec.  
63.2445(i).
    (e) Non-applicable referenced provisions. The referenced provisions 
specified in paragraphs (e)(1) through (16) of this section do not 
apply when demonstrating compliance with this section.
* * * * *

[[Page 23871]]


0
28. Amend Sec.  63.2515 by revising paragraph (d) to read as follows:


Sec.  63.2515  What notifications must I submit and when?

* * * * *
    (d) Supplement to Notification of Compliance Status. You must also 
submit supplements to the Notification of Compliance Status as 
specified in Sec.  63.2520(d)(3) through (6).

0
29. Amend Sec.  63.2520 by:
0
a. Revising paragraph (d) introductory text;
0
b. Adding paragraph (d)(6);
0
c. Revising paragraphs (e) introductory text, (e)(2), (e)(14)(iii), 
(e)(16), (f) and (g); and
0
d. Removing paragraphs (h) and (i).
    The addition and revisions read as follows:


Sec.  63.2520  What reports must I submit and when?

* * * * *
    (d) Notification of compliance status report. You must submit a 
notification of compliance status report according to the schedule in 
paragraph (d)(1) of this section, and the notification of compliance 
status report must contain the information specified in paragraphs 
(d)(2) through (6) of this section.
* * * * *
    (6) For adsorbers subject to the requirements of Sec.  
63.2450(e)(7), you must also submit the information listed in 
paragraphs (d)(6)(i) and (ii) of this section in a supplement to the 
Notification of Compliance Status within 150 days after the first 
applicable compliance date.
    (i) Whether the adsorber cannot be regenerated or is a regenerative 
adsorber(s) that is regenerated off site.
    (ii) The breakthrough limit and adsorber bed life established 
during the initial performance test or design evaluation of the 
adsorber.
    (e) Compliance report. The compliance report must contain the 
information specified in paragraphs (e)(1) through (17) of this 
section. On and after August 12, 2023 or once the reporting template 
for this subpart has been available on the CEDRI website for 1 year, 
whichever date is later, you must submit all subsequent reports 
following the procedure specified in Sec.  63.9(k), except any medium 
submitted through mail must be sent to the attention of the 
Miscellaneous Organic Chemical Manufacturing Sector Lead. You must use 
the appropriate electronic report template on the CEDRI website 
(https://www.epa.gov/electronic-reporting-air-emissions/cedri) for this 
subpart. The date report templates become available will be listed on 
the CEDRI website. Unless the Administrator or delegated state agency 
or other authority has approved a different schedule for submission of 
reports under Sec. Sec.  63.9(i) and 63.10(a) of subpart A, the report 
must be submitted by the deadline specified in this subpart, regardless 
of the method in which the report is submitted.
* * * * *
    (2) Statement by a responsible official with that official's name, 
title, and signature, certifying the accuracy of the content of the 
report. If your report is submitted via CEDRI, the certifier's 
electronic signature during the submission process replaces the 
requirement in this paragraph (e)(2).
* * * * *
    (14) * * *
    (iii) The lower explosive limit in percent, vessel pressure in 
psig, or mass in pounds of VOC in the equipment, as applicable, at the 
start of atmospheric venting. If the 5 psig vessel pressure option in 
Sec.  63.2450(v)(1)(ii) was used and active purging was initiated while 
the concentration of the vapor was 10 percent or greater of its LEL, 
also include the concentration of the vapors at the time active purging 
was initiated.
* * * * *
    (16) For each heat exchange system subject to Sec.  63.2490(d) or 
(e), beginning no later than the compliance dates specified in Sec.  
63.2445(g), the reporting requirements of Sec.  63.104(f)(2) no longer 
apply; instead, the compliance report must include the information 
specified in paragraphs (e)(16)(i) through (v) of this section.
    (i) The number of heat exchange systems at the plant site subject 
to the monitoring requirements in Sec.  63.2490(d) or (e) during the 
reporting period;
    (ii) The number of heat exchange systems subject to the monitoring 
requirements in Sec.  63.2490(d) or (e) at the plant site found to be 
leaking during the reporting period;
    (iii) For each monitoring location where a leak was identified 
during the reporting period, identification of the monitoring location 
(e.g., unique monitoring location or heat exchange system ID number), 
the measured total strippable hydrocarbon concentration or total 
hydrocarbon mass emissions rate (if complying with Sec.  63.2490(d)) or 
the measured concentration of the monitored substance(s) (if complying 
with Sec.  63.2490(e)), the date the leak was first identified, and, if 
applicable, the date the source of the leak was identified;
    (iv) For leaks that were repaired during the reporting period 
(including delayed repairs), identification of the monitoring location 
associated with the repaired leak, the total strippable hydrocarbon 
concentration or total hydrocarbon mass emissions rate (if complying 
with Sec.  63.2490(d)) or the measured concentration of the monitored 
substance(s) (if complying with Sec.  63.2490(e)) measured during re-
monitoring to verify repair, and the re-monitoring date (i.e., the 
effective date of repair); and
    (v) For each delayed repair, identification of the monitoring 
location associated with the leak for which repair is delayed, the date 
when the delay of repair began, the date the repair is expected to be 
completed (if the leak is not repaired during the reporting period), 
the total strippable hydrocarbon concentration or total hydrocarbon 
mass emissions rate (if complying with Sec.  63.2490(d)) or the 
measured concentration of the monitored substance(s) (if complying with 
Sec.  63.2490(e)) and date of each monitoring event conducted on the 
delayed repair during the reporting period, and an estimate in pounds 
of the potential total hydrocarbon emissions or monitored substance(s) 
emissions over the reporting period associated with the delayed repair.
* * * * *
    (f) Performance test reports. Beginning no later than October 13, 
2020, you must submit performance test reports in accordance with this 
paragraph (f). Unless otherwise specified in this subpart, within 60 
days after the date of completing each performance test required by 
this subpart, you must submit the results of the performance test 
following the procedures specified in Sec.  63.9(k). Data collected 
using test methods supported by the EPA's Electronic Reporting Tool 
(ERT) as listed on the EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at 
the time of the test must be submitted in a file format generated 
through the use of the EPA's ERT. Alternatively, you may submit an 
electronic file consistent with the extensible markup language (XML) 
schema listed on the EPA's ERT website. Data collected using test 
methods that are not supported by the EPA's ERT as listed on the EPA's 
ERT website at the time of the test must be included as an attachment 
in the ERT or alternate electronic file.
    (g) CEMS relative accuracy test audit (RATA) Performance evaluation 
reports. Beginning no later than October 13, 2020, you must start 
submitting CEMS RATA performance evaluation reports in accordance with 
this paragraph (g).

[[Page 23872]]

Unless otherwise specified in this subpart, within 60 days after the 
date of completing each continuous monitoring system performance 
evaluation (as defined in Sec.  63.2) that includes a RATA, you must 
submit the results of the performance evaluation following the 
procedures specified in Sec.  63.9(k). The results of performance 
evaluations of CEMS measuring RATA pollutants that are supported by the 
EPA's ERT as listed on the EPA's ERT website at the time of the 
evaluation must be submitted in a file format generated through the use 
of the EPA's ERT. Alternatively, you may submit an electronic file 
consistent with the XML schema listed on the EPA's ERT website. The 
results of performance evaluations of CEMS measuring RATA pollutants 
that are not supported by the EPA's ERT as listed on the EPA's ERT 
website at the time of the evaluation must be included as an attachment 
in the ERT or alternate electronic file.

0
30. Amend Sec.  63.2525 by:
0
a. Revising paragraphs (o), (p)(2), (p)(3), (p)(5), (q)(2), (r)(1), 
(r)(4)(iv) introductory text, (r)(4)(iv)(B) and (r)(4)(iv)(C); and
0
b. Adding paragraph (r)(4)(iv)(D).
    The addition and revisions read as follows:


Sec.  63.2525  What records must I keep?

* * * * *
    (o) For each nonregenerative adsorber and regenerative adsorber 
that is regenerated offsite subject to the requirements in Sec.  
63.2450(e)(7), you must keep the applicable records specified in 
paragraphs (o)(1) through (3) of this section.
    (1) Breakthrough limit and bed life established according to Sec.  
63.2450(e)(7)(i).
    (2) Each outlet HAP or TOC concentration measured according to 
Sec. Sec.  63.2450(e)(7)(ii) and (e)(7)(iii).
    (3) Date and time you last replaced the adsorbent.
    (p) * * *
    (2) If complying with the requirements of Sec.  63.2450(v)(1)(i) 
and the concentration of the vapor at the time of the vessel opening 
exceeds 10 percent of its LEL, identification of the maintenance vent, 
the process units or equipment associated with the maintenance vent, 
the date of maintenance vent opening, and the concentration of the 
vapor at the time of the vessel opening.
    (3) If complying with the requirements of Sec.  63.2450(v)(1)(ii) 
and either the vessel pressure at the time of the vessel opening 
exceeds 5 psig or the concentration of the vapor at the time of the 
active purging was initiated exceeds 10 percent of its LEL, 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, the date of maintenance vent 
opening, the pressure of the vessel or equipment at the time of 
discharge to the atmosphere and, if applicable, the concentration of 
the vapors in the equipment when active purging was initiated.
* * * * *
    (5) If complying with the requirements of Sec.  63.2450(v)(1)(iv), 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, records documenting actions taken 
to comply with other applicable alternatives and why utilization of 
this alternative was required, the date of maintenance vent opening, 
the equipment pressure and concentration of the vapors in the equipment 
at the time of discharge, an indication of whether active purging was 
performed and the pressure of the equipment during the installation or 
removal of the blind if active purging was used, the duration the 
maintenance vent was open during the blind installation or removal 
process, and records used to estimate the total quantity of VOC in the 
equipment at the time the maintenance vent was opened to the atmosphere 
for each applicable maintenance vent opening.
    (q) * * *
    (2) Records of the number of releases during each calendar year 
and, prior to June 3, 2024, the number of those releases for which the 
root cause was determined to be a force majeure event. Keep these 
records for the current calendar year and the past 5 calendar years.
* * * * *
    (r) * * *
    (1) Monitoring data required by Sec.  63.2490(d) and (e) that 
indicate a leak, the date the leak was detected, or, if applicable, the 
basis for determining there is no leak.
* * * * *
    (4) * * *
    (iv) An estimate of the potential total hydrocarbon emissions (if 
you monitor the cooling water for leaks according to Sec.  
63.2490(d)(1)) or monitored substance(s) emissions (if you monitor the 
cooling water for leaks according to Sec.  63.2490(e)) from the leaking 
heat exchange system or heat exchanger for each required delay of 
repair monitoring interval following the procedures in paragraphs 
(r)(4)(iv)(A) through (D) of this section.
* * * * *
    (B) For delay of repair monitoring intervals prior to repair of the 
leak, calculate the potential total hydrocarbon emissions or monitored 
substance(s) emissions for the leaking heat exchange system or heat 
exchanger for the monitoring interval by multiplying the mass emissions 
rate, determined in Sec.  63.2490(d)(1)(iii)(B) or paragraph 
(r)(4)(iv)(A) or (D) of this section, by the duration of the delay of 
repair monitoring interval. The duration of the delay of repair 
monitoring interval is the time period starting at midnight on the day 
of the previous monitoring event or at midnight on the day the repair 
would have had to be completed if the repair had not been delayed, 
whichever is later, and ending at midnight of the day the of the 
current monitoring event.
    (C) For delay of repair monitoring intervals ending with a repaired 
leak, calculate the potential total hydrocarbon emissions or monitored 
substance(s) emissions for the leaking heat exchange system or heat 
exchanger for the final delay of repair monitoring interval by 
multiplying the duration of the final delay of repair monitoring 
interval by the mass emissions rate determined for the last monitoring 
event prior to the re-monitoring event used to verify the leak was 
repaired. The duration of the final delay of repair monitoring interval 
is the time period starting at midnight of the day of the last 
monitoring event prior to re-monitoring to verify the leak was repaired 
and ending at the time of the re-monitoring event that verified that 
the leak was repaired.
    (D) If you monitor the cooling water for leaks according to Sec.  
63.2490(e), you must calculate the mass emissions rate by determining 
the mass flow rate of the cooling water at the monitoring location 
where the leak was detected. Cooling water mass flow rates may be 
determined using direct measurement, pump curves, heat balance 
calculations, or other engineering methods. Once determined, multiply 
the mass flow rate of the cooling water by the concentration of the 
measured substance(s).
* * * * *

0
31. Amend Sec.  63.2550 by revising the entry ``In ethylene oxide 
service'' to read as follows:


Sec.  63.2550  What definitions apply to this subpart?

* * * * *
    In ethylene oxide service means the following:
    (1) For equipment leaks, any equipment that contains or contacts a 
fluid (liquid or gas) that is at least 0.1 percent by weight of 
ethylene oxide. If information exists that suggests ethylene

[[Page 23873]]

oxide could be present in equipment, the equipment is considered to be 
``in ethylene oxide service'' unless sampling and analysis is performed 
as specified in Sec.  63.2492 to demonstrate that the equipment does 
not meet the definition of being ``in ethylene oxide service''. 
Examples of information that could suggest ethylene oxide could be 
present in equipment, include calculations based on safety data sheets, 
material balances, process stoichiometry, or previous test results 
provided the results are still relevant to the current operating 
conditions.
    (2) For process vents, 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). If 
information exists that suggests ethylene oxide could be present in a 
batch or continuous process vent, then the batch or continuous process 
vent is considered to be ``in ethylene oxide service'' unless an 
analysis is performed as specified in Sec.  63.2492 to demonstrate that 
the batch or continuous process vent does not meet the definition of 
being ``in ethylene oxide service''. Examples of information that could 
suggest ethylene oxide could be present in a batch or continuous 
process vent, include calculations based on safety data sheets, 
material balances, process stoichiometry, or previous test results 
provided the results are still relevant to the current operating 
conditions.
    (3) For storage tanks, storage tanks of any capacity and vapor 
pressure storing a liquid that is at least 0.1 percent by weight of 
ethylene oxide. If knowledge exists that suggests ethylene oxide could 
be present in a storage tank, then the storage tank is considered to be 
``in ethylene oxide service'' unless the procedures specified in Sec.  
63.2492 are performed to demonstrate that the storage tank does not 
meet the definition of being ``in ethylene oxide service''. The 
exemptions for ``vessels storing organic liquids that contain HAP only 
as impurities'' and ``pressure vessels designed to operate in excess of 
204.9 kilopascals and without emissions to the atmosphere'' listed in 
the definition of ``storage tank'' in this section do not apply for 
storage tanks that may be in ethylene oxide service. Examples of 
information that could suggest ethylene oxide could be present in a 
storage tank, 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.
* * * * *

0
32. Revise table 10 to subpart FFFF of part 63 to read as follows:

Table 10 to Subpart FFFF of Part 63--Work Practice Standards for Heat 
Exchange Systems

    As required in Sec.  63.2490, you must meet each requirement in the 
following table that applies to your heat exchange systems:

------------------------------------------------------------------------
            For each . . .                       You must . . .
------------------------------------------------------------------------
Heat exchange system, as defined in    a. Comply with the requirements
 Sec.   63.101.                         of Sec.   63.104 and the
                                        requirements referenced therein,
                                        except as specified in Sec.
                                        63.2490(b) and (c); or
                                       b. Comply with the requirements
                                        in Sec.   63.2490(d); or
                                       c. Comply with the requirements
                                        in Sec.   63.2490(e).
------------------------------------------------------------------------


0
33. Amend table 12 to subpart FFFF of part 63 by revising entry 
``63.9(k)'' to read as follows:

Table 12 to Subpart FFFF of Part 63--Applicability of General 
Provisions to Subpart FFFF

* * * * *

------------------------------------------------------------------------
           Citation                     Subject            Explanation
------------------------------------------------------------------------
 
                              * * * * * * *
Sec.   63.9(k)................  Electronic reporting    Yes.
                                 procedures.
 
                              * * * * * * *
------------------------------------------------------------------------

[FR Doc. 2024-05906 Filed 4-3-24; 8:45 am]
BILLING CODE 6560-50-P