Rule2024-07002
New Source Performance Standards for the Synthetic Organic Chemical Manufacturing Industry and National Emission Standards for Hazardous Air Pollutants for the Synthetic Organic Chemical Manufacturing Industry and Group I & II Polymers and Resins Industry
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
May 16, 2024
Effective
July 15, 2024
Issuing agencies
Environmental Protection Agency
Abstract
This action finalizes amendments to the New Source Performance Standards (NSPS) that apply to the Synthetic Organic Chemical Manufacturing Industry (SOCMI) and amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) that apply to the SOCMI (more commonly referred to as the Hazardous Organic NESHAP or HON) and Group I and II Polymers and Resins (P&R I and P&R II, respectively) Industries. The EPA is finalizing decisions resulting from the Agency's technology review of the HON and the P&R I and P&R II NESHAP, and its review of the NSPS that apply to the SOCMI. The EPA is also finalizing amendments to the NSPS for equipment leaks of volatile organic compounds (VOC) in SOCMI based on its reconsideration of certain issues raised in an administrative petition for reconsideration. Furthermore, the EPA is finalizing emission standards for ethylene oxide (EtO) emissions and chloroprene emissions after considering the results of a risk assessment for the HON and for Neoprene Production processes subject to the P&R I NESHAP, and is finalizing a fenceline monitoring work practice standard for certain hazardous air pollutants (HAP). Lastly, the EPA is finalizing the removal of exemptions from standards for periods of startup, shutdown, and malfunction (SSM), adding work practice standards for such periods where appropriate, finalizing standards for previously unregulated HAP, and adding provisions for electronic reporting of performance test reports and periodic reports.
Full Text
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[Federal Register Volume 89, Number 96 (Thursday, May 16, 2024)]
[Rules and Regulations]
[Pages 42932-43297]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-07002]
[[Page 42931]]
Vol. 89
Thursday,
No. 96
May 16, 2024
Part II
Environmental Protection Agency
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40 CFR Parts 60 and 63
New Source Performance Standards for the Synthetic Organic Chemical
Manufacturing Industry and National Emission Standards for Hazardous
Air Pollutants for the Synthetic Organic Chemical Manufacturing
Industry and Group I & II Polymers and Resins Industry; Final Rule
Federal Register / Vol. 89, No. 96 / Thursday, May 16, 2024 / Rules
and Regulations
[[Page 42932]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 60 and 63
[EPA-HQ-OAR-2022-0730; FRL-9327-02-OAR]
RIN 2060-AV71
New Source Performance Standards for the Synthetic Organic
Chemical Manufacturing Industry and National Emission Standards for
Hazardous Air Pollutants for the Synthetic Organic Chemical
Manufacturing Industry and Group I & II Polymers and Resins Industry
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This action finalizes amendments to the New Source Performance
Standards (NSPS) that apply to the Synthetic Organic Chemical
Manufacturing Industry (SOCMI) and amendments to the National Emission
Standards for Hazardous Air Pollutants (NESHAP) that apply to the SOCMI
(more commonly referred to as the Hazardous Organic NESHAP or HON) and
Group I and II Polymers and Resins (P&R I and P&R II, respectively)
Industries. The EPA is finalizing decisions resulting from the Agency's
technology review of the HON and the P&R I and P&R II NESHAP, and its
review of the NSPS that apply to the SOCMI. The EPA is also finalizing
amendments to the NSPS for equipment leaks of volatile organic
compounds (VOC) in SOCMI based on its reconsideration of certain issues
raised in an administrative petition for reconsideration. Furthermore,
the EPA is finalizing emission standards for ethylene oxide (EtO)
emissions and chloroprene emissions after considering the results of a
risk assessment for the HON and for Neoprene Production processes
subject to the P&R I NESHAP, and is finalizing a fenceline monitoring
work practice standard for certain hazardous air pollutants (HAP).
Lastly, the EPA is finalizing the removal of exemptions from standards
for periods of startup, shutdown, and malfunction (SSM), adding work
practice standards for such periods where appropriate, finalizing
standards for previously unregulated HAP, and adding provisions for
electronic reporting of performance test reports and periodic reports.
DATES: This final rule is effective on July 15, 2024. The incorporation
by reference (IBR) of certain publications listed in the rule is
approved by the Director of the Federal Register as of July 15, 2024.
The incorporation by reference of certain other material listed in the
rule was approved by the Director of the Federal Register as of October
17, 2000 and November 16, 2007.
ADDRESSES: The U.S. Environmental Protection Agency (EPA) has
established a docket for this action under Docket ID No. EPA-HQ-OAR-
2022-0730. All documents in the docket are listed on the <a href="https://www.regulations.gov/">https://www.regulations.gov/</a> website. Although listed, some information is not
publicly available, e.g., Confidential Business Information (CBI) or
other information whose disclosure is restricted by statute. Certain
other material, such as copyrighted material, is not placed on the
internet and will be publicly available only in hard copy form.
Publicly available docket materials are available either electronically
through <a href="https://www.regulations.gov/">https://www.regulations.gov/</a>, or in hard copy at the EPA Docket
Center, WJC West Building, Room Number 3334, 1301 Constitution Ave. NW,
Washington, DC. The Public Reading Room hours of operation are 8:30
a.m. to 4:30 p.m. Eastern Standard Time, Monday through Friday. The
telephone number for the Public Reading Room is (202) 566-1744, and the
telephone number for the EPA Docket Center is (202) 566-1742.
FOR FURTHER INFORMATION CONTACT: For questions about the HON and SOCMI
NSPS, contact U.S. EPA, Attn: Mr. Andrew Bouchard, Mail Drop: Sector
Policies and Programs Division (E143-01), 109 T.W. Alexander Drive,
P.O. Box 12055, RTP, North Carolina 27711; telephone number: (919) 541-
4036; and email address: <a href="/cdn-cgi/l/email-protection#e0828f958388819284ce818e84928597a0859081ce878f96"><span class="__cf_email__" data-cfemail="9dfff2e8fef5fceff9b3fcf3f9eff8eaddf8edfcb3faf2eb">[email protected]</span></a>. For questions about
the P&R I and P&R II NESHAP, contact U.S. EPA, Attn: Ms. Njeri Moeller,
Mail Drop: Sector Policies and Programs Division (E143-01), 109 T.W.
Alexander Drive, P.O. Box 12055, RTP, North Carolina 27711; telephone
number: (919) 541-1380; and email address: <a href="/cdn-cgi/l/email-protection#d6bbb9b3babab3a4f8b8bcb3a4bf96b3a6b7f8b1b9a0"><span class="__cf_email__" data-cfemail="cca1a3a9a0a0a9bee2a2a6a9bea58ca9bcade2aba3ba">[email protected]</span></a>. For
specific information regarding the risk modeling methodology, contact
U.S. EPA, Attn: Mr. Matthew Woody, Mail Drop: Health and Environmental
Impacts Division (C539-02), 109 T.W. Alexander Drive, P.O. Box 12055,
RTP, North Carolina 27711; telephone number: (919) 541-1535; and email
address: <a href="/cdn-cgi/l/email-protection#bccbd3d3d8c592d1ddc8c8d4d9cbfcd9ccdd92dbd3ca"><span class="__cf_email__" data-cfemail="21564e4e45580f4c405555494456614451400f464e57">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Preamble acronyms and abbreviations. We use multiple acronyms and
terms in this preamble. While this list may not be exhaustive, to ease
the reading of this preamble and for reference purposes, the EPA
defines the following terms and acronyms here:
ACS American Community Survey
AERMOD American Meteorological Society/EPA Regulatory Model
dispersion modeling system
ANSI American National Standards Institute
APCD air pollution control device
API American Petroleum Institute
ASME American Society of Mechanical Engineers
BACT best available control technology
BLR basic liquid epoxy resins
BPT benefit per-ton
BSER best system of emissions reduction
BTEX benzene, toluene, ethylbenzene, and xylenes
CAA Clean Air Act
CBI confidential business information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CMPU chemical manufacturing process unit
CO carbon monoxide
CO<INF>2</INF> carbon dioxide
CPI consumer price index
CRA Congressional Review Act
EAV equivalent annual value
ECHO Enforcement and Compliance History Online
EFR external floating roof
EIS Emission Information System
EPA Environmental Protection Agency
EPPU elastomer product process unit
ERT Electronic Reporting Tool
EtO ethylene oxide
FTIR fourier transform infrared
HAP hazardous air pollutant(s)
HON Hazardous Organic NESHAP
HQ hazard quotient
HQ<INF>REL</INF> hazard quotient reference exposure level
IBR incorporation by reference
ICR information collection request
IFR internal floating roof
IRIS Integrated Risk Information System
ISA Integrated Science Assessment
km kilometer
LAER lowest achievable emissions rate
lb/hr pound per hour
lb/yr pound per year
LDAR leak detection and repair
LDEQ Louisiana Department of Environmental Quality
LEL lower explosive limit
MACT maximum achievable control technology
MDL method detection limit
MERP monomer emission reduction project
MIR maximum individual lifetime [cancer] risk
MON Miscellaneous Organic Chemical Manufacturing NESHAP
MTVP maximum true vapor pressure
NAICS North American Industry Classification System
NAAQS National Ambient Air Quality Standards
NATTS National Air Toxic Trends Station
NEI National Emissions Inventory
NESHAP national emission standards for hazardous air pollutants
NO<INF>X</INF> nitrogen oxides
N<INF>2</INF>O nitrous oxide
[[Page 42933]]
NPDES national pollutant discharge elimination system
NRDC Natural Resources Defense Council
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
NYSDEC New York State Department of Environmental Conservation
OAR Office of Air and Radiation
OEL open-ended valves or lines
OGI optical gas imaging
OIG Office of Inspector General
OMB Office of Management and Budget
P&R I Group I Polymers and Resins
P&R II Group II Polymers and Resins
PDF portable document format
PMPU polyether polyol manufacturing process unit
POM polycyclic organic matter
ppbv parts per billion by volume
ppm parts per million
ppmv parts per million by volume
ppmw parts per million by weight
PRA Paperwork Reduction Act
psig pounds per square inch gauge
PRD pressure relief device
PV present value
RACT reasonably available control technology
RDL representative detection limit
REL reference exposure level
RFA Regulatory Flexibility Act
RIA Regulatory Impact Analysis
RTO regenerative thermal oxidizer
RTR risk and technology review
SCAQMD South Coast Air Quality Management District
scfm standard cubic feet per minute
scmm standard cubic meter per minute
SOCMI Synthetic Organic Chemical Manufacturing Industry
SO<INF>2</INF> sulfur dioxide
SSM startup, shutdown, and malfunction
TAC Texas Administrative Code
TCEQ Texas Commission on Environmental Quality
TCI total capital investment
TOC total organic compounds
TOSHI target organ-specific hazard index
tpy tons per year
TRE total resource effectiveness
TRI Toxics Release Inventory
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
U.S.C. United States Code
VCS voluntary consensus standards
VOC volatile organic compound(s)
WSR wet strength resins
WWTP wastewater treatment plant
Background information. On April 25, 2023, the EPA proposed
amendments to the NSPS that apply to the SOCMI, and amendments to the
HON and P&R I and P&R II NESHAP. In this action, we are finalizing
decisions and revisions for the rule. We summarize some of the more
significant comments we timely received regarding the proposed rule and
provide our responses in this preamble. A summary of all other public
comments on the proposal and the EPA's responses to those comments is
available in the document titled Summary of Public Comments and
Responses for New Source Performance Standards for the Synthetic
Organic Chemical Manufacturing Industry and National Emission Standards
for Hazardous Air Pollutants for the Synthetic Organic Chemical
Manufacturing Industry and Group I & II Polymers and Resins Industry,
Docket ID No. EPA-HQ-OAR-2022-0730. A ``track changes'' version of the
regulatory language that incorporates the changes in this action is
available in the docket.
Organization of this document.
The information in this preamble is organized as follows:
I. General Information
A. Executive Summary
B. Does this action apply to me?
C. Where can I get a copy of this document and other related
information?
D. Judicial Review and Administrative Reconsideration
II. Background
A. What is the statutory authority for this action?
B. What are the source categories and how did the previous
standards regulate emissions?
C. What changes did we propose in our April 25, 2023, proposal?
III. What is included in this final rule?
A. What are the final rule amendments based on the risk review
for the SOCMI and Neoprene Production source categories NESHAP?
B. What are the final rule amendments based on the technology
review for the SOCMI, P&R I, and P&R II source categories NESHAP
pursuant to CAA section 112(d)(6) and NSPS reviews for the SOCMI
source category pursuant to CAA section 111(b)(1)(B)?
C. What are the final rule amendments pursuant to CAA sections
112(d)(2) and (3), and 112(h) for the SOCMI, P&R I, and P&R II
source categories?
D. What are the final rule amendments addressing emissions
during periods of SSM?
E. What are the final amendments addressing the NSPS Subparts VV
and VVa reconsideration?
F. What other changes have been made to the NESHAP and NSPS?
G. What are the effective and compliance dates of the standards?
IV. What is the rationale for our final decisions and amendments for
the SOCMI, P&R I, and P&R II source categories?
A. Residual Risk Review for the SOCMI and Neoprene Production
Source Categories NESHAP
B. Technology Review for the SOCMI, P&R I, and P&R II Source
Categories NESHAP and NSPS Review for the SOCMI Source Category
C. Amendments Pursuant to CAA Section 112(d)(2) and (3) and
112(h) for the SOCMI, P&R I, and P&R II Source Categories NESHAP
D. Amendments Addressing Emissions During Periods of SSM
E. Amendments Addressing NSPS Subparts VV and VVa
Reconsideration
F. Other Amendments to the NESHAP and NSPS
V. Summary of Cost, Environmental, and Economic Impacts and
Additional Analyses Conducted
A. What are the affected sources?
B. What are the air quality impacts?
C. What are the cost impacts?
D. What are the economic impacts?
E. What are the benefits?
F. What analysis of environmental justice did we conduct?
G. Children's Environmental Health
VI. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 14094: Modernizing Regulatory Review
B. Paperwork Reduction Act (PRA)
C. Regulatory Flexibility Act (RFA)
D. Unfunded Mandates Reform Act (UMRA)
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination with
Indian Tribal Governments
G. Executive Order 13045: Protection of Children from
Environmental Health Risks and Safety Risks
H. Executive Order 13211: Actions Concerning Regulations that
Significantly Affect Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act (NTTAA) and
1 CFR part 51
J. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations and Executive Order 14096: Revitalizing Our Nation's
Commitment to Environmental Justice for All
K. Congressional Review Act (CRA)
I. General Information
A. Executive Summary
1. Purpose of the Regulatory Action
The source categories that are the subject of this final action are
the SOCMI and various polymers and resins manufacturing source
categories. The SOCMI source category includes chemical manufacturing
processes producing commodity chemicals while the polymers and resins
manufacturing source categories covered in this action include
elastomers production processes and resin production processes that use
epichlorohydrin feedstocks (see sections I.B and II.B of this preamble
for detailed information about these source categories). The EPA has
previously promulgated maximum achievable control technology (MACT)
standards for certain processes in the SOCMI source category in the HON
rulemaking at 40 Code of Federal Regulations (CFR) part 63, subparts F,
G, and H. In 1994, the EPA finalized MACT standards in subparts F, G,
and
[[Page 42934]]
H for SOCMI processes (59 FR 19454),\1\ and the Agency completed a
residual risk and technology review (RTR) for these NESHAP in 2006 (71
FR 76603). In 1995, the EPA finalized MACT standards in the P&R II
NESHAP (40 CFR part 63, subpart W) for epoxy resin and non-nylon
polyamide resin manufacturing processes (60 FR 12670), and the Agency
completed a residual RTR for these standards in 2008 (73 FR 76220). In
1996, the EPA finalized MACT standards in the P&R I NESHAP (40 CFR part
63, subpart U) for various elastomer manufacturing processes (61 FR
46906), and the Agency completed residual RTRs for these standards in
2008 and 2011 (73 FR 76220 and 76 FR 22566).
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\1\ Around the same time, the EPA set MACT standards for
equipment leaks from certain non-SOCMI processes at chemical plants
regulated under 40 CFR part 63, subpart I (59 FR 19587).
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The EPA has also promulgated NSPS for certain processes in the
SOCMI source category. In 1983, the EPA finalized NSPS (40 CFR part 60,
subpart VV) for equipment leaks of VOC in SOCMI (48 FR 48328). In 1990,
the EPA finalized NSPS (40 CFR part 60, subparts III and NNN) for VOC
from air oxidation unit processes and distillation operations (55 FR
26912 and 55 FR 26931). In 1993, the EPA finalized NSPS (40 CFR part
60, subpart RRR) for VOC from reactor processes (58 FR 45948). In 2007,
the EPA promulgated NSPS (40 CFR part 60, subpart VVa) for VOC from
certain equipment leaks (72 FR 64883), which reflect the EPA's review
and revision of the standards in 40 CFR part 60, subpart VV.
The statutory authority for this action is sections 111, 112,
301(a)(1), and 307(d)(7)(B) of the CAA. Section 111(b)(1)(B) of the CAA
requires the EPA to promulgate standards of performance for new sources
in any category of stationary sources that the Administrator has listed
pursuant to 111(b)(1)(A). Section 111(a)(1) of the CAA provides that
these performance standards are to ``reflect[ ] the degree of emission
limitation achievable through the application of the best system of
emission reduction which (taking into account the cost of achieving
such reduction and any nonair quality health and environmental impact
and energy requirements) the Administrator determines has been
adequately demonstrated.'' We refer to this level of control as the
best system of emissions reduction or ``BSER.'' Section 111(b)(1)(B) of
the CAA requires the EPA to ``at least every 8 years, review and, if
appropriate, revise'' the NSPS.
For NESHAP, CAA section 112(d)(2) requires the EPA to establish
MACT standards for listed categories of major sources of HAP. Section
112(d)(6) of the CAA requires the EPA to review standards promulgated
under CAA section 112, and revise them ``as necessary (taking into
account developments in practices, processes, and control
technologies),'' no less often than every eight years following
promulgation of those standards. This is referred to as a ``technology
review'' and is required for all standards established under CAA
section 112. Section 112(f) of the CAA requires the EPA to assess the
risk to public health remaining after the implementation of MACT
emission standards promulgated under CAA section 112(d)(2). If the MACT
standards for a source category do not provide ``an ample margin of
safety to protect public health,'' the EPA must also promulgate health-
based standards for that source category to further reduce risk from
HAP emissions.
Section 301(a)(1) of the CAA authorizes the Administrator to
prescribe such regulations as are necessary to carry out his functions
under the CAA. Section 307(d)(7)(B) of the CAA requires the
reconsideration of a rule only if the person raising an objection to
the rule can demonstrate that it was impracticable to raise such
objection during the period for public comment or if the grounds for
the objection arose after the comment period (but within the time
specified for judicial review), and if the objection is of central
relevance to the outcome of the rule.
The final new NSPS for SOCMI equipment leaks, air oxidation unit
processes, distillation operations, and reactor processes (i.e., NSPS
subparts VVb, IIIa, NNNa, and RRRa, respectively) are based on the
Agency's review of the current NSPS (subparts VVa, III, NNN, and RRR)
pursuant to CAA section 111(b)(1)(B), which requires that the EPA
review the NSPS every eight years and, if appropriate, revise them. In
addition, the EPA is finalizing amendments to the NSPS for equipment
leaks of VOC in SOCMI based on its reconsideration of certain aspects
of subparts VV and VVa that were raised in an administrative petition
which the Agency granted pursuant to section 307(d)(7)(B) of the CAA.
The final amendments to the HON (NESHAP subparts F, G, H, and I), the
P&R I NESHAP (NESHAP subpart U), and the P&R II NESHAP (NESHAP subpart
W) are based on the Agency's review of the current NESHAP (subparts F,
G, H, I, U, and W) pursuant to CAA sections 112(d) and (f).
Due to the development of the EPA's Integrated Risk Information
System (IRIS) inhalation unit risk estimate (URE) for chloroprene in
2010, the EPA conducted a second CAA section 112(f) risk review for the
SOCMI source category and Neoprene Production source category. In the
first step of the CAA section 112(f)(2) determination of risk
acceptability for this rulemaking, the use of the 2010 chloroprene risk
value resulted in the EPA identifying unacceptable cancer risk driven
by chloroprene emissions from the sole affected source producing
neoprene subject to the P&R I NESHAP.\2\ Consequently, the final
amendments to the P&R I NESHAP address the EPA review of additional
control technologies, beyond those analyzed in the technology review
conducted for the P&R I source category, to address the unacceptable
risk and achieve an ample margin of safety to protect public health at
that affected source.
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\2\ As discussed in section III.B of the proposal preamble (see
88 FR 25080, April 25, 2023), chloroprene emissions from HON
processes do not on their own present unacceptable cancer risk from
the SOCMI source category.
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Additionally, in 2016, the EPA updated the IRIS inhalation URE for
EtO. In the first step of the CAA section 112(f)(2) determination of
risk acceptability for this rulemaking, the use of the updated 2016 EtO
risk value resulted in the EPA identifying unacceptable cancer risk
driven by EtO emissions from HON processes. Consequently, the final
amendments to the HON also address the EPA review of additional control
technologies, beyond those analyzed in the technology review conducted
for the SOCMI source category, to address the unacceptable risk and
achieve an ample margin of safety to protect public health at SOCMI and
P&R I affected sources.
2. Summary of the Major Provisions of the Regulatory Action In Question
The most significant amendments that we are finalizing are
described briefly below. However, all of our final amendments,
including amendments to remove exemptions for periods of SSM, are
discussed in detail with rationale in section IV of this preamble or in
the document titled Summary of Public Comments and Responses for New
Source Performance Standards for the Synthetic Organic Chemical
Manufacturing Industry and National Emission Standards for Hazardous
Air Pollutants for the Synthetic Organic Chemical Manufacturing
Industry and Group I & II Polymers and Resins Industry, which is
available in the docket for this rulemaking.
[[Page 42935]]
a. HON
We are finalizing amendments to the HON for heat exchange systems,
process vents, storage vessels, transfer racks, wastewater, and
equipment leaks.
i. NESHAP Subpart F
<bullet> As detailed in section II.B.1.a of this preamble, NESHAP
subpart F contains provisions to determine which chemical manufacturing
processes at a facility are subject to the HON, monitoring requirements
for HAP (i.e., HAP listed in Table 4 of NESHAP subpart F) that may leak
into cooling water from heat exchange systems, and requirements for
maintenance wastewater. For NESHAP subpart F, we are finalizing:
<bullet> compliance dates for all of the HON requirements in this
action (see 40 CFR 63.100(k)(10) through (12); and section III.G of
this preamble).
<bullet> the moving of all the definitions from NESHAP subparts G
and H (i.e., 40 CFR 63.111 and 40 CFR 63.161, respectively) into the
definition section of NESHAP subpart F (see 40 CFR 63.101; and sections
III.F and IV.F of this preamble).
<bullet> a new definition for ``in ethylene oxide service'' (for
equipment leaks, heat exchange systems, process vents, storage vessels,
and wastewater) (see 40 CFR 63.101; and sections III.A and IV.A of this
preamble).
<bullet> new operating and monitoring requirements for flares (see
40 CFR 63.108; and sections III.C and IV.C of this preamble).
<bullet> sampling and analysis procedures for owners and operators
to demonstrate that process equipment does, or does not, meet the
definition of being ``in ethylene oxide service'' (see 40 CFR 63.109;
and sections III.A and IV.A of this preamble).
For heat exchange systems, we are finalizing:
<bullet> requirements that owners or operators must use the
Modified El Paso Method and repair leaks of total strippable
hydrocarbon concentration (as methane) in the stripping gas of 6.2
parts per million by volume (ppmv) or greater (see 40 CFR 63.104(g)
through (j); and sections III.B.1 and IV.B of this preamble).
<bullet> requirements for heat exchange systems in EtO service that
owners or operators must conduct more frequent leak monitoring (weekly
instead of quarterly) and repair leaks of total strippable hydrocarbon
concentration (as methane) in the stripping gas of 6.2 ppmv or greater
within 15 days from the sampling date (in lieu of the previous 45-day
repair requirement after receiving results of monitoring indicating a
leak in the HON), and delay of repair is not allowed unless the
equipment can be isolated such that it is no longer in EtO service (see
40 CFR 63.104(g)(6) and (h)(6); and sections III.A.1 and IV.A of this
preamble).
<bullet> a provision allowing use of the previous leak monitoring
requirements for heat exchange systems at 40 CFR 63.104(b) in limited
instances in lieu of using the Modified El Paso Method for heat
exchange systems cooling process fluids that will remain in the cooling
water if a leak occurs (see 40 CFR 63.104(l); and sections III.B.1 and
IV.B of this preamble).
ii. NESHAP Subpart G
As detailed in section II.B.1.b of this preamble, NESHAP subpart G
contains requirements for process vents, storage vessels, transfer
racks, wastewater streams, and closed vent systems.
For process vents, we are finalizing:
<bullet> the removal of the 50 ppmv and 0.005 standard cubic meter
per minute (scmm) Group 1 process vent thresholds from the Group 1
process vent definition, and instead we are requiring owners and
operators of process vents that emit greater than or equal to 1.0 pound
per hour (lb/hr) of total organic HAP to reduce emissions of organic
HAP using a flare meeting the operating and monitoring requirements for
flares in NESHAP subpart F; or reduce emissions of total organic HAP or
total organic compounds (TOC) by 98 percent by weight or to an exit
concentration of 20 ppmv, (see 40 CFR 63.101 and 40 CFR 63.113(a)(1)
and (2); and sections III.B.1 and IV.B of this preamble).
<bullet> the removal of the total resource effectiveness (TRE)
concept in its entirety (see 40 CFR 63.113(a)(4); and sections III.B.1
and IV.B of this preamble).
<bullet> an emission standard of 0.054 nanograms per dry standard
cubic meter (ng/dscm) at 3 percent oxygen (toxic equivalency basis) for
dioxins and furans from chlorinated process vents (see 40 CFR
63.113(a)(5); and sections III.C and IV.C of this preamble).
<bullet> requirements that owners and operators must reduce
emissions of EtO from process vents in EtO service by either: (1)
Venting emissions through a closed-vent system to a control device that
reduces EtO by greater than or equal to 99.9 percent by weight, to a
concentration less than 1 ppmv for each process vent, or to less than 5
pound per year (lb/yr) for all combined process vents per chemical
manufacturing process unit (CMPU); or (2) venting emissions through a
closed-vent system to a flare meeting the operating and monitoring
requirements for flares in NESHAP subpart F (see 40 CFR 63.113(j), 40
CFR 63.108, and 40 CFR 63.124; and sections III.A.1 and IV.A of this
preamble).\3\
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\3\ We are also removing the option to allow use of a design
evaluation in lieu of performance testing to demonstrate compliance
for controlling various emission sources in EtO service. In
addition, owners or operators that choose to control emissions with
a non-flare control device are required to conduct an initial
performance test on each control device in EtO service to verify
performance at the required level of control, and are required to
conduct periodic performance testing on non-flare control devices in
EtO service every 5 years (see 40 CFR 63.124).
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<bullet> a work practice standard for maintenance vents requiring
that, prior to opening process equipment to the atmosphere, the
equipment must either: (1) Be drained and purged to a closed system so
that the hydrocarbon content is less than or equal to 10 percent of the
lower explosive limit (LEL); (2) be opened and vented to the atmosphere
only if the 10-percent LEL cannot be demonstrated and the pressure is
less than or equal to 5 pounds per square inch gauge (psig), provided
there is no active purging of the equipment to the atmosphere until the
LEL criterion is met; (3) be opened when there is less than 50 lbs of
VOC that may be emitted to the atmosphere; or (4) for installing or
removing an equipment blind, depressurize the equipment to 2 psig or
less and maintain pressure of the equipment where purge gas enters the
equipment at or below 2 psig during the blind flange installation,
provided none of the other work practice standards can be met (see 40
CFR 63.113(k); and sections III.C and IV.C of this preamble).
<bullet> requirements that owners and operators of process vents in
EtO service are allowed to use the maintenance vent work practice
standards; however, owners and operators are prohibited from releasing
more than 1.0 ton of EtO from all maintenance vents combined on a
facility basis in any consecutive 12-month period (see 40 CFR
63.113(k)(4); and sections III.A.1 and IV.A of this preamble).
For storage vessels, we are finalizing:
<bullet> requirements that owners and operators must reduce
emissions of EtO from storage vessels in EtO service by either: (1)
Venting emissions through a closed-vent system to a control device that
reduces EtO by greater than or equal to 99.9 percent by weight or to a
concentration less than 1 ppmv for each storage vessel vent; or (2)
venting emissions through a closed-vent system to a flare meeting the
operating and monitoring requirements for flares in NESHAP subpart F
(see 40 CFR 63.119(a)(5), 40 CFR 63.108, and 40 CFR
[[Page 42936]]
63.124; and sections III.A.1 and IV.A of this preamble).\4\
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\4\ See footnote 3.
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<bullet> a work practice standard to allow storage vessels to be
vented to the atmosphere once a storage vessel degassing concentration
threshold is met (i.e., once a storage vessel degassing organic HAP
concentration of 5,000 ppmv as methane is met, or until the vapor space
concentration is less than 10 percent of the LEL) and all standing
liquid has been removed from the vessel to the extent practicable (see
40 CFR 63.119(a)(6); and sections III.C and IV.C of this preamble).
<bullet> a definition for ``pressure vessel'' and removing the
exemption for ``pressure vessels designed to operate in excess of 204.9
kilopascals and without emissions to the atmosphere'' from the
definition of storage vessel (see 40 CFR 63.101); and requirements for
initial and annual performance testing of pressure vessels that are
considered Group 1 storage vessels using EPA Method 21 of 40 CFR part
60, appendix A-7 to demonstrate no detectable emissions (i.e., required
to meet a leak definition of 500 parts per million (ppm) at each point
on the pressure vessel where total organic HAP could potentially be
emitted) (see 40 CFR 63.119(a)(7); and sections III.C and IV.C of this
preamble).
<bullet> requirements that all openings in an internal floating
roof (IFR) (except those for automatic bleeder vents (vacuum breaker
vents), rim space vents, leg sleeves, and deck drains) be equipped with
a deck cover; and that the deck cover be equipped with a gasket between
the cover and the deck (see 40 CFR 63.119(b)(5)(ix); and sections
III.B.1 and IV.B of this preamble).
<bullet> control requirements for guidepoles for all storage
vessels equipped with an IFR (see 40 CFR 63.119(b)(5)(x), (xi), and
(xii); and sections III.B.1 and IV.B of this preamble).
<bullet> a work practice standard that applies during periods of
planned routine maintenance of a control device, fuel gas system, or
process equipment that is normally used for compliance with the storage
vessel emissions control requirements; owners and operators are not
permitted to fill the storage vessel during these periods (such that
working losses are controlled and the vessel only emits HAP to the
atmosphere due to breathing losses for a limited amount of time) (see
40 CFR 63.119(e)(7); and sections III.C and IV.C of this preamble).
<bullet> revisions to the Group 1 storage capacity criterion (for
storage vessels at existing sources) from between 75 cubic meters
(m\3\) and 151 m\3\ to between 38 m\3\ and 151 m\3\ (see Table 5 to
subpart G; and sections III.B.1 and IV.B of this preamble).
<bullet> revisions to the Group 1 stored-liquid maximum true vapor
pressure (MTVP) of total organic HAP threshold (for storage vessels at
existing and new sources) from greater than or equal to 13.1
kilopascals to greater than or equal to 6.9 kilopascals (see Tables 5
and 6 to subpart G; and sections III.B.1 and IV.B of this preamble).
For transfer racks, we are finalizing:
<bullet> removing the exemption for transfer operations that load
``at an operating pressure greater than 204.9 kilopascals'' from the
definition of transfer operation (see 40 CFR 63.101; and sections III.C
and IV.C of this preamble).
For wastewater streams, we are finalizing:
<bullet> revisions to the Group 1 wastewater stream threshold to
include wastewater streams in EtO service (i.e., wastewater streams
with total annual average concentration of EtO greater than or equal to
1 parts per million by weight (ppmw) at any flow rate) (see 40 CFR
63.132(c)(1)(iii) and (d)(1)(ii); and sections III.A and IV.A of this
preamble).
<bullet> requirements prohibiting owners and operators from
injecting wastewater into or disposing of water through any heat
exchange system in a CMPU meeting the conditions of 40 CFR 63.100(b)(1)
through (3) if the water contains any amount of EtO, has been in
contact with any process stream containing EtO, or the water is
considered wastewater as defined in 40 CFR 63.101 (see 40 CFR
63.104(k); and sections III.A and IV.A of this preamble).
For closed vent systems, we are finalizing:
<bullet> requirements that owners and operators may not bypass an
air pollution control device (APCD) at any time (see 40 CFR
63.114(d)(3), 40 CFR 63.127(d)(3), and 40 CFR 63.148(f)(4)), that a
bypass is a violation, and that owners and operators must estimate and
report the quantity of organic HAP released (see 40 CFR 63.118(a)(5),
40 CFR 63.130(a)(2)(iv), 40 CFR 63.130(b)(3), 40 CFR 63.130(d)(7), and
40 CFR 63.148(i)(3)(iii) and (j)(4); and sections III.C and IV.C of
this preamble).
iii. NESHAP Subparts H and I
As detailed in sections II.B.1.c and II.B.1.d of this preamble,
NESHAP subparts H and I contain requirements for equipment leaks. Also,
due to space limitations in NESHAP subpart F, we are finalizing
fenceline monitoring (i.e., monitoring along the perimeter of the
facility's property line) in NESHAP subpart H for all emission sources.
For equipment leaks and fenceline monitoring, we are finalizing:
<bullet> requirements that all connectors in EtO service be
monitored monthly at a leak definition of 100 ppm with no skip period,
and delay of repair is not allowed unless the equipment can be isolated
such that it is no longer in EtO service (see 40 CFR 63.174(a)(3),
(b)(3)(vi), and (g)(3), and 40 CFR 63.171(f); and sections III.A and
IV.A of this preamble).
<bullet> requirements that all gas/vapor and light liquid valves in
EtO service be monitored monthly at a leak definition of 100 ppm with
no skip period, and delay of repair is not allowed unless the equipment
can be isolated such that it is no longer in EtO service (see 40 CFR
63.168(b)(2)(iv) and (d)(5), and 40 CFR 63.171(f); and sections III.A
and IV.A of this preamble).
<bullet> requirements that all light liquid pumps in EtO service be
monitored monthly at a leak definition of 500 ppm, and delay of repair
is not allowed unless the equipment can be isolated such that it is no
longer in EtO service (see 40 CFR 63.163(a)(1)(iii), (b)(2)(iv),
(c)(4), and (e)(7), and 40 CFR 63.171(f); and sections III.A and IV.A
of this preamble).
<bullet> a work practice standard for pressure relief devices
(PRDs) that vent to the atmosphere that require owners and operators to
implement at least three prevention measures, perform root cause
analysis and corrective action in the event that a PRD does release
emissions directly to the atmosphere, and monitor PRDs using a system
that is capable of identifying and recording the time and duration of
each pressure release and of notifying operators that a pressure
release has occurred (see 40 CFR 63.165(e); and sections III.C and IV.C
of this preamble).
<bullet> requirements that all surge control vessels and bottoms
receivers meet the requirements we are finalizing for process vents
(see 40 CFR 63.170(b); and sections III.C and IV.C of this preamble).
<bullet> requirements that owners and operators may not bypass an
APCD at any time (see 40 CFR 63.114(d)(3), 40 CFR 63.127(d)(3), and 40
CFR 63.148(f)(4)), that a bypass is a violation, and that owners and
operators must estimate and report the quantity of organic HAP released
(see 40 CFR 63.118(a)(5), 40 CFR 63.130(a)(2)(iv), 40 CFR 63.130(b)(3),
40 CFR 63.130(d)(7), and 40 CFR 63.148(i)(3)(iii) and (j)(4); and
sections III.C and IV.C of this preamble).
<bullet> fenceline monitoring work practice standards requiring
owners and operators to monitor for any of six
[[Page 42937]]
specific HAP (i.e., benzene, 1,3-butadiene, ethylene dichloride, vinyl
chloride, EtO, and chloroprene) if their affected source uses,
produces, stores, or emits any of them, and conduct root cause analysis
and corrective action upon exceeding annual average concentration
action levels set forth for each HAP (see 40 CFR 63.184; and sections
III.B.1 and IV.B of this preamble).
b. P&R I NESHAP
As detailed in section II.B.2 of this preamble, the P&R I NESHAP
(40 CFR part 63, subpart U) generally follows and refers to the
requirements of the HON, with additional requirements for batch process
vents. We are finalizing amendments to the P&R I NESHAP for heat
exchange systems, process vents, storage vessels, wastewater, and
equipment leaks. For NESHAP subpart U, we are finalizing:
<bullet> compliance dates for all of the requirements in this
action related to the P&R I NESHAP (see 40 CFR 63.481(n) and (o); and
section III.G of this preamble).
<bullet> new operating and monitoring requirements for flares (see
40 CFR 63.508; and sections III.C and IV.C of this preamble).
<bullet> the removal of the provisions to assert an affirmative
defense to civil penalties (see 40 CFR 63.480(j)(4); and sections III.D
and IV.D of this preamble).
<bullet> the same fenceline monitoring requirements that we are
finalizing in Subpart H for HON sources.
<bullet> sampling and analysis procedures for owners and operators
of affected sources producing neoprene to demonstrate that process
equipment does, or does not, meet the definition of being ``in
chloroprene service'' (see 40 CFR 63.509; and sections III.A and IV.A
of this preamble).
For heat exchange systems, we are finalizing:
<bullet> the same requirements (except for EtO standards) listed in
section I.A.2.a.i of this preamble that we are finalizing for heat
exchange systems subject to the HON to also apply to heat exchange
systems subject to the P&R I NESHAP (see 40 CFR 63.502(n)(7); and
sections III.B.1 and IV.B of this preamble).
For continuous front-end process vents, we are finalizing:
<bullet> the requirement that owners and operators must reduce
emissions of chloroprene from continuous front-end process vents in
chloroprene service at affected sources producing neoprene by venting
emissions through a closed-vent system to a non-flare control device
that reduces chloroprene by greater than or equal to 98 percent by
weight, to a concentration less than 1 ppmv for each process vent, or
to less than 5 lb/yr for all combined process vents per elastomer
product process unit (EPPU) (see 40 CFR 63.485(y), and 40 CFR 63.510;
and sections III.A and IV.A of this preamble).\5\
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\5\ We are also removing the option to allow use of a design
evaluation in lieu of performance testing to demonstrate compliance
for controlling various emission sources in chloroprene service. In
addition, owners or operators are required to conduct an initial
performance test on each non-flare control device in chloroprene
service to verify performance at the required level of control, and
are required to conduct periodic performance testing on non-flare
control devices in chloroprene service every 5 years (see 40 CFR
63.510).
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<bullet> the same requirements (except for EtO standards) listed in
section I.A.2.a.ii of this preamble that we are finalizing for process
vents subject to the HON to also apply to continuous front-end process
vents subject to the P&R I NESHAP (see 40 CFR 63.482, 40 CFR
63.485(l)(6), (o)(6), (p)(5), and (x), 40 CFR 63.113(a)(1) and (2), 40
CFR 63.113(a)(4), 40 CFR 63.113(k), 40 CFR 63.114(a)(5)(v); and
sections III.B.1 and IV.B of this preamble).
<bullet> requirements that owners and operators of continuous
front-end process vents in chloroprene service are allowed to use the
maintenance vent work practice standards; however, owners and operators
are prohibited from releasing more than 1.0 ton of chloroprene from all
maintenance vents combined on a facility basis in any consecutive 12-
month period (see 40 CFR 63.485(z); and sections III.A and IV.A of this
preamble).
<bullet> the same dioxins and furans emission standard that we are
finalizing for process vents subject to the HON of 0.054 ng/dscm at 3
percent oxygen (toxic equivalency basis) to also apply to chlorinated
continuous front-end process vents (see 40 CFR 63.485(x); and sections
III.C and IV.C of this preamble).
For batch front-end process vents, we are finalizing:
<bullet> the removal of the annual organic HAP emissions mass flow
rate, cutoff flow rate, and annual average batch vent flow rate Group 1
process vent thresholds from the Group 1 batch front-end process vent
definition (these thresholds were previously determined on an
individual batch process vent basis). Instead, owners and operators of
batch front-end process vents that release total annual organic HAP
emissions greater than or equal to 4,536 kilograms per year (kg/yr)
(10,000 pounds per year (lb/yr)) from all batch front-end process vents
combined are required to reduce emissions of organic HAP from these
process vents using a flare meeting the operating and monitoring
requirements for flares; or reduce emissions of organic HAP or total
organic carbon (TOC) by 90 percent by weight (or to an exit
concentration of 20 ppmv if considered an ``aggregate batch vent
stream'' as defined by the rule) (see 40 CFR 63.482, 40 CFR
63.487(e)(1)(iv), 40 CFR 63.488(d)(2), (e)(4), (f)(2), and (g)(3); and
sections III.B.1 and IV.B of this preamble).
<bullet> the same chloroprene standards that we are finalizing for
continuous front-end process for batch front-end process vents at
affected sources producing neoprene (see 40 CFR 63.487(j); and sections
III.A and IV.A of this preamble).
<bullet> the same work practice standards that we are finalizing
for maintenance vents as described for HON to the P&R I NESHAP (see 40
CFR 63.487(i); and sections III.C and IV.C of this preamble).
<bullet> requirements that owners and operators of batch front-end
process vents in chloroprene service are allowed to use the maintenance
vent work practice standards; however, owners and operators are
prohibited from releasing more than 1.0 ton of chloroprene from all
maintenance vents combined on a facility basis in any consecutive 12-
month period (see 40 CFR 63.487(i)(4); and sections III.A and IV.A of
this preamble).
<bullet> the same dioxins and furans emission standard that we are
finalizing for process vents subject to the HON of 0.054 ng/dscm at 3
percent oxygen (toxic equivalency basis) to also apply to chlorinated
batch front-end process vents (see 40 CFR 63.487(a)(3) and (b)(3); and
sections III.C and IV.C of this preamble).
For back-end process vents, we are finalizing:
<bullet> a requirement that owners and operators reduce emissions
of chloroprene from back-end process vents in chloroprene service at
affected sources producing neoprene by venting emissions through a
closed-vent system to a non-flare control device that reduces
chloroprene by greater than or equal to 98 percent by weight, to a
concentration less than 1 ppmv for each process vent, or to less than 5
lb/yr for all combined process vents (see 40 CFR 63.494(a)(7); and
sections III.A and IV.A of this preamble).
For storage vessels, we are finalizing:
<bullet> the requirement that owners and operators reduce emissions
of chloroprene from storage vessels in chloroprene service at affected
sources producing neoprene by venting emissions through a closed-vent
system to a non-flare control device that reduces chloroprene by
greater than or equal to 98 percent by weight or to a
[[Page 42938]]
concentration less than 1 ppmv for each storage vessel vent (see 40 CFR
63.484(u) and 40 CFR 63.510; and sections III.A and IV.A of this
preamble).\6\
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\6\ See footnote 5.
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<bullet> the same requirements (except for EtO standards) listed in
section I.A.2.a.ii of this preamble that we are finalizing for storage
vessels subject to the HON except the requirements apply to storage
vessels subject to the P&R I NESHAP (see 40 CFR 63.484(t); and sections
III.B.1 and IV.B of this preamble).
For wastewater streams, we are finalizing:
<bullet> the Group 1 wastewater stream threshold to include
wastewater streams in chloroprene service at affected sources producing
neoprene (i.e., wastewater streams with total annual average
concentration of chloroprene greater than or equal to 10 ppmw at any
flow rate) (see 40 CFR 63.501(a)(10)(iv); and sections III.A and IV.A
of this preamble).
<bullet> requirements prohibiting owners and operators from
injecting wastewater into or disposing of water through any heat
exchange system in an EPPU if the water contains any amount of
chloroprene, has been in contact with any process stream containing
chloroprene, or the water is considered wastewater as defined in 40 CFR
63.482 (see 40 CFR 63.502(n)(8); and sections III.A and IV.A of this
preamble).
For equipment leaks and fenceline monitoring, we are finalizing:
<bullet> the same requirements (except for EtO standards) listed in
section I.A.2.a.iii of this preamble that we are finalizing for
equipment leaks subject to the HON except the requirements apply to
equipment leaks subject to the P&R I NESHAP (see 40 CFR 63.502(a)(1)
through (a)(6); and sections III.C and IV.C of this preamble).
<bullet> the cross-reference in the P&R I NESHAP to the fenceline
monitoring work practice standards in the HON (see 40 CFR 63.502)
requiring owners and operators to monitor for any of six specific HAP
(i.e., benzene, 1,3-butadiene, ethylene dichloride, vinyl chloride,
EtO, and chloroprene) if their affected source uses, produces, stores,
or emits any of them, and conduct root cause analysis and corrective
action upon exceeding annual average concentration action levels set
forth for each HAP (see sections III.B.1 and IV.B of this preamble),
plus a lower annual average concentration action level for chloroprene
applicable to neoprene production source category (see sections III.A
and IV.A of this preamble).
c. P&R II NESHAP
The most significant amendments that we are finalizing for the P&R
II NESHAP (40 CFR part 63, subpart W) are requirements for heat
exchange systems (see 40 CFR 63.523(d) and 40 CFR 63.524(c); and
sections III.C and IV.C of this preamble) and requirements for owners
and operators of wet strength resins (WSR) sources to comply with both
the equipment leak standards in the HON and the HAP emissions
limitation for process vents, storage tanks, and wastewater systems
(see 40 CFR 63.524(a)(3) and (b)(3); and sections III.C and IV.C of
this preamble). We are also finalizing the same dioxin and furan
emission standard of 0.054 ng/dscm at 3 percent oxygen (toxic
equivalency basis) for chlorinated process vents as in the HON and the
P&R I NESHAP (see 40 CFR 63.523(e) (for process vents associated with
each existing, new, or reconstructed affected basic liquid epoxy resins
(BLR) source), 40 CFR 63.524(a)(3) (for process vents associated with
each existing affected WSR source), and 40 CFR 63.524(b)(3) (for
process vents associated with each new or reconstructed affected WSR
source); and see sections III.C and IV.C of this preamble).
d. NSPS Subparts III, NNN, and RRR
We are amending the applicability of NSPS subparts III, NNN, and
RRR so that they only apply to sources constructed, reconstructed, or
modified on or before April 25, 2023. Affected facilities that are
constructed, reconstructed, or modified after April 25, 2023, are
subject to the new NSPS subparts IIIa, NNNa, and RRRa.
e. NSPS Subparts IIIa, NNNa, and RRRa
Rather than comply with a TRE concept which is used in NSPS
subparts III, NNN, and RRR, we are finalizing in new NSPS subparts
IIIa, NNNa, and RRRa a requirement for owners and operators to reduce
emissions of TOC (minus methane and ethane) from all vent streams of an
affected facility (i.e., SOCMI air oxidation unit processes,
distillation operations, and reactor processes for which construction,
reconstruction, or modification occurs after April 25, 2023) by 98
percent by weight or to a concentration of 20 ppmv on a dry basis
corrected to 3 percent oxygen, or combust the emissions in a flare
meeting the same operating and monitoring requirements for flares that
we are finalizing for flares subject to the HON. We are finalizing a
mass-based exemption criterion of 0.001 lb/hr TOC (for which emission
controls are not required) in new NSPS subparts IIIa and NNNa. We are
also not including a relief valve discharge exemption in the definition
of ``vent stream'' in new NSPS subparts IIIa, NNNa, and RRRa; instead,
any relief valve discharge to the atmosphere of a vent stream is a
violation of the emissions standard. In addition, we are finalizing in
new NSPS subparts IIIa, NNNa, and RRRa the same work practice standards
for maintenance vents that we are finalizing for HON process vents, and
the same monitoring requirements that we are finalizing for HON process
vents for adsorbers that cannot be regenerated and regenerative
adsorbers that are regenerated offsite (see sections III.B.2 and IV.B
of this preamble).
f. NSPS Subpart VVa
We are amending certain aspects of NSPS subparts VV and VVa to
address issues raised in an administrative petition which the Agency
granted pursuant to section 307(d)(7)(B) of the CAA. In addition, we
are amending the applicability of the existing NSPS subpart VVa so that
it applies to sources constructed, reconstructed, or modified after
November 6, 2006, and on or before April 25, 2023. Affected facilities
that are constructed, reconstructed, or modified after April 25, 2023,
are subject to the new NSPS subpart VVb.
g. NSPS Subpart VVb
We are finalizing in a new NSPS subpart VVb the same requirements
in NSPS subpart VVa plus a requirement that all gas/vapor and light
liquid valves be monitored quarterly at a leak definition of 100 ppm
and all connectors be monitored once every 12 months at a leak
definition of 500 ppm (see sections III.B.2 and IV.B of this preamble).
For each of these two additional requirements, we are also finalizing
skip periods for good performance.
3. Costs and Benefits
Pursuant to E.O. 12866, the EPA prepared an analysis of the
potential costs and benefits associated with this action. This
analysis, titled Regulatory Impact Analysis for the Final New Source
Performance Standards for the Synthetic Organic Chemical Manufacturing
Industry and National Emission Standards for Hazardous Air Pollutants
for the Synthetic Organic Chemical Manufacturing Industry and Group I &
II Polymers and Resins Industry (referred to as the RIA in this
document), is available in the docket, and is also briefly summarized
in section V of this preamble. The assessment of costs and benefits
described herein and in the RIA is
[[Page 42939]]
presented solely for the purposes of complying with E.O. 12866 and to
provide the public with a complete depiction of the impacts of this
final action. The EPA notes that analysis of costs and benefits in the
RIA is distinct from the determinations finalized in this action under
CAA sections 111 and 112, which are based on the statutory factors the
EPA is required to consider under those sections.
B. Does this action apply to me?
Regulated entities. Categories and entities potentially regulated
by this action are the SOCMI source category (and whose facilities,
sources and processes we often refer to as ``HON facilities,'' ``HON
sources,'' and ``HON processes'' for purposes of the NESHAP) and
several Polymers and Resins Production source categories covered in the
P&R I and P&R II NESHAP (see section II.B of this preamble for detailed
information about the source categories).\7\ The North American
Industry Classification System (NAICS) code for SOCMI facilities begins
with 325, for P&R I facilities is 325212, and for P&R II facilities is
325211. The list of NAICS codes is not intended to be exhaustive, but
rather provides a guide for readers regarding the entities that this
final action is likely to affect.
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\7\ The P&R I NESHAP includes MACT standards for nine listed
elastomer production source categories (i.e., Butyl Rubber
Production, Epichlorohydrin Elastomers Production, Ethylene-
Propylene Elastomers Production, Hypalon<SUP>TM</SUP> Production,
Neoprene Production, Nitrile Butadiene Rubber Production,
Polybutadiene Rubber Production, Polysulfide Rubber Production, and
Styrene-Butadiene Rubber and Latex Production). The P&R II NESHAP
includes MACT standards for two listed source categories that use
epichlorohydrin feedstock (Epoxy Resins Production and Non-Nylon
Polyamides Production).
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As defined in the Initial List of Categories of Sources Under
Section 112(c)(1) of the Clean Air Act Amendments of 1990 (see 57 FR
31576, July 16, 1992) and Documentation for Developing the Initial
Source Category List, Final Report (see EPA-450/3-91-030, July 1992),
the SOCMI source category is any facility engaged in ``manufacturing
processes that produce one or more of the chemicals [listed] that
either: (1) Use an organic HAP as a reactant or (2) produce an organic
HAP as a product, co-product, by-product, or isolated intermediate.''
\8\ In the development of NESHAP for this source category, the EPA
considered emission sources associated with: equipment leaks (including
leaks from heat exchange systems), process vents, transfer racks,
storage vessels, and wastewater collection and treatment systems. The
elastomer production source categories in the P&R I NESHAP and resins
produced with epichlorohydrin feedstock in the P&R II NESHAP have many
similar emission sources with SOCMI sources and are discussed further
in section II.B of this preamble.
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\8\ The original list of chemicals is located in Appendix A
(beginning on page A-71) of EPA-450/3-91-030 dated July 1992.
Alternatively, the most recent list of chemicals is documented in
the HON applicability rule text at 40 CFR 63.100(b)(1) and (2). The
original list of organic HAPs for the SOCMI source category is
located in Table 3.1 of Section 3.0 of EPA-450/3-91-030.
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The EPA Priority List (40 CFR 60.16, 44 FR 49222, August 21, 1979)
included ``Synthetic Organic Chemical Manufacturing'' \9\ as a source
category for which standards of performance were to be promulgated
under CAA section 111. In the development of NSPS subparts VVa, III,
NNN, and RRR for this source category, the EPA considered emission
sources associated with unit processes, storage and handling equipment,
fugitive emission sources, and secondary sources.
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\9\ For readability, we also refer to this as the SOCMI source
category for purposes of the NSPS.
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To determine whether your facility is affected, you should examine
the applicability criteria in the appropriate NESHAP or NSPS. If you
have any questions regarding the applicability of any aspect of these
NESHAP and NSPS, please contact the appropriate person listed in the
preceding FOR FURTHER INFORMATION CONTACT section of this preamble.
C. Where can I get a copy of this document and other related
information?
In addition to being available in the docket, an electronic copy of
this final action will also be available on the internet. Following
signature by the EPA Administrator, the EPA will post a copy of this
final action at: <a href="https://www.epa.gov/stationary-sources-air-pollution/synthetic-organic-chemical-manufacturing-industry-organic-national">https://www.epa.gov/stationary-sources-air-pollution/synthetic-organic-chemical-manufacturing-industry-organic-national</a>,
<a href="https://www.epa.gov/stationary-sources-air-pollution/group-i-polymers-and-resins-national-emission-standards-hazardous">https://www.epa.gov/stationary-sources-air-pollution/group-i-polymers-and-resins-national-emission-standards-hazardous</a>, and <a href="https://www.epa.gov/stationary-sources-air-pollution/epoxy-resins-production-and-non-nylon-polyamides-national-emission">https://www.epa.gov/stationary-sources-air-pollution/epoxy-resins-production-and-non-nylon-polyamides-national-emission</a>. Following publication in
the Federal Register, the EPA will post the Federal Register version
and key technical documents at these same websites.
Additional information is available on the RTR website at <a href="https://www.epa.gov/stationary-sources-air-pollution/risk-and-technology-review-national-emissions-standards-hazardous">https://www.epa.gov/stationary-sources-air-pollution/risk-and-technology-review-national-emissions-standards-hazardous</a>. This information
includes an overview of the RTR program and links to project websites
for the RTR source categories.
D. Judicial Review and Administrative Reconsideration
Under CAA section 307(b)(1), judicial review of this final action
is available only by filing a petition for review in the United States
Court of Appeals for the District of Columbia Circuit (the Court) by
July 15, 2024. Under CAA section 307(b)(2), the requirements
established by these final rules may not be challenged separately in
any civil or criminal proceedings brought to enforce the requirements.
Section 307(d)(7)(B) of the CAA further provides that only an
objection to a rule or procedure which was raised with reasonable
specificity during the period for public comment (including any public
hearing) may be raised during judicial review. This section also
provides a mechanism for the EPA to reconsider the rule if the person
raising an objection can demonstrate to the Administrator that it was
impracticable to raise such objection within the period for public
comment or if the grounds for such objection arose after the period for
public comment (but within the time specified for judicial review) and
if such objection is of central relevance to the outcome of the rule.
Any person seeking to make such a demonstration should submit a
Petition for Reconsideration to the Office of the Administrator, U.S.
EPA, Room 3000, WJC South Building, 1200 Pennsylvania Ave. NW,
Washington, DC 20460, with a copy to both the person(s) listed in the
preceding FOR FURTHER INFORMATION CONTACT section, and the Associate
General Counsel for the Air and Radiation Law Office, Office of General
Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania Ave. NW,
Washington, DC 20460.
II. Background
A. What is the statutory authority for this action?
1. NESHAP
The statutory authority for this action related to NESHAP is
provided by sections 112 and 301 of the CAA, as amended (42 U.S.C. 7401
et seq.). Section 112 of the CAA establishes a two-stage regulatory
process to develop standards for emissions of HAP from stationary
sources. ``Major sources'' are those that emit, or have the potential
to emit, any single HAP at a rate of 10 tpy or more, or 25 tpy or more
of any combination of HAP. For major sources,
[[Page 42940]]
these standards are commonly referred to as MACT standards and must
reflect the maximum degree of emission reductions of HAP achievable
(after considering cost, energy requirements, and non-air quality
health and environmental impacts). In developing MACT standards, CAA
section 112(d)(2) directs the EPA to consider the application of
measures, processes, methods, systems, or techniques, including, but
not limited to, those that reduce the volume of or eliminate HAP
emissions through process changes, substitution of materials, or other
modifications; enclose systems or processes to eliminate emissions;
collect, capture, or treat HAP when released from a process, stack,
storage, or fugitive emissions point; are design, equipment, work
practice, or operational standards; or any combination of the above.
The MACT standards may take the form of design, equipment, work
practice or operational standards where the EPA first determines either
that (1) a pollutant cannot be emitted through a conveyance designed
and constructed to emit or capture the pollutant, or that any
requirement for, or use of, such a conveyance would be inconsistent
with law; or (2) the application of measurement methodology to a
particular class of sources is not practicable due to technological and
economic limitations. CAA section 112(h)(1)-(2).
For these MACT standards, the statute specifies certain minimum
stringency requirements, which are referred to as MACT floor
requirements, and which may not be based on cost considerations. See
CAA section 112(d)(3). For new sources, the MACT floor cannot be less
stringent than the emission control achieved in practice by the best-
controlled similar source. The MACT standards for existing sources can
be less stringent than floors for new sources, but they cannot be less
stringent than the average emission limitation achieved by the best-
performing 12 percent of existing sources in the category or
subcategory (or the best-performing five sources for categories or
subcategories with fewer than 30 sources). In developing MACT
standards, we must also consider control options that are more
stringent than the floor under CAA section 112(d)(2). We may establish
standards more stringent than the floor, based on the consideration of
the cost of achieving the emissions reductions, any non-air quality
health and environmental impacts, and energy requirements.
In the second stage of the regulatory process, the CAA requires the
EPA to undertake two different analyses, which we refer to as the
technology review and the residual risk review. Under the technology
review, we must review the technology-based standards and revise them
``as necessary (taking into account developments in practices,
processes, and control technologies)'' no less frequently than every 8
years, pursuant to CAA section 112(d)(6). In conducting this review,
the EPA is not required to recalculate the MACT floors that were
established in earlier rulemakings. Natural Resources Defense Council
(NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008); Association of
Battery Recyclers, Inc. v. EPA, 716 F.3d 667 (D.C. Cir. 2013). The EPA
may consider cost in deciding whether to revise the standards pursuant
to CAA section 112(d)(6). The EPA is required to address regulatory
gaps, such as missing standards for listed air toxics known to be
emitted from the source category, and any new MACT standards must be
established under CAA sections 112(d)(2) and (3), or, in specific
circumstances, CAA sections 112(d)(4) or (h). Louisiana Environmental
Action Network v. EPA, 955 F.3d 1088 (D.C. Cir. 2020). Under the
residual risk review, we must evaluate the risk to public health
remaining after application of the technology-based standards and
revise the standards, if necessary, to provide an ample margin of
safety to protect public health or to prevent, taking into
consideration costs, energy, safety, and other relevant factors, an
adverse environmental effect. The residual risk review is required
within 8 years after promulgation of the MACT standards, pursuant to
CAA section 112(f). In conducting the residual risk review, if the EPA
determines that the current standards provide an ample margin of safety
to protect public health, it is not necessary to revise the MACT
standards pursuant to CAA section 112(f).\10\ For more information on
the statutory authority for this rule, see 88 FR 25080, April 25, 2023.
Often, the CAA section 112(d)(6) technology review and the CAA section
112(f)(2) residual risk review are combined into a single rulemaking
action, commonly called a ``risk and technology review'' (RTR).
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\10\ The Court has affirmed this approach of implementing CAA
section 112(f)(2)(A): NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir.
2008) (``If EPA determines that the existing technology-based
standards provide an 'ample margin of safety,' then the Agency is
free to readopt those standards during the residual risk
rulemaking.'').
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The EPA conducted a combined RTR for the HON in 2006, concluding
that there was no need to revise the HON under the provisions of either
CAA section 112(f) or 112(d)(6). As part of the residual risk review,
the EPA conducted a risk assessment and, based on the results of the
risk assessment, determined that the then-current level of control
called for by the existing MACT standards both reduced HAP emissions to
levels that presented an acceptable level of risk and provided an ample
margin of safety to protect public health (see 71 FR 76603, December
21, 2006 for additional details). In 2008, the EPA conducted a combined
RTR for four of the P&R I source categories (including the Polysulfide
Rubber Production, Ethylene-Propylene Elastomers Production, Butyl
Rubber Production, and Neoprene Production source categories) and all
P&R II source categories (Epoxy Resins Production and Non-Nylon
Polyamides Production source categories). In 2011, the EPA completed
the combined RTR for the remaining five P&R I source categories
(Epichlorohydrin Elastomers Production, Hypalon\TM\ Production,
Polybutadiene Rubber Production, Styrene-Butadiene Rubber and Latex
Production, and Nitrile Butadiene Rubber Production). The EPA concluded
in these actions that there was no need to revise standards for any of
the nine P&R I source categories and two P&R II source categories under
the provisions of either CAA section 112(f) or 112(d)(6) (see 73 FR
76220, December 16, 2008 and 77 FR 22566, April 21, 2011 for additional
details).\11\
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\11\ We note that in the April 21, 2011, rulemaking (see 77 FR
22566), the EPA finalized amendments to eliminate the SSM exemption
in the P&R I NESHAP; however, for consistency with the SSM related
amendments that we are finalizing for the HON and the P&R II NESHAP,
we are also finalizing (as detailed in section IV.D of this
preamble) additional amendments to the P&R I NESHAP related to the
SSM exemption that were not addressed in the April 21, 2011, P&R I
rule.
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This action constitutes another CAA section 112(d)(6) technology
review for the HON and the P&R I and P&R II NESHAP. This action also
constitutes an updated CAA section 112(f) risk review based on new
information for the HON and for affected sources producing neoprene
subject to the P&R I NESHAP. We note that although there is no
statutory CAA obligation under CAA section 112(f) for the EPA to
conduct a second residual risk review of the HON or of standards for
affected sources producing neoprene subject to the P&R I NESHAP, the
EPA retains discretion to revisit its residual risk reviews where the
Agency deems that to be warranted. See, e.g., Fed. Commc'ns Comm'n v.
Fox Television Stations, Inc., 556 U.S. 502,
[[Page 42941]]
515 (2009); Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins.
Co., 463 U.S. 29, 42 (1983); Ethylene Oxide Emissions Standards for
Sterilization Facilities; Final Decision, 71 FR 17712, 17715 col. 1
(April 7, 2006) (asserting authority, in residual risk review for EtO,
for EPA ``to revisit (and revise, if necessary) any rulemaking if there
is sufficient evidence that changes within the affected industry or
significant improvements to science suggests the public is exposed to
significant increases in risk as compared to the risk assessment
prepared for the rulemaking (e.g., CAA section 301).'').
Here, the specific changes to health information related to certain
pollutants emitted by these unique categories led us to determine that
it is appropriate, in this case, to conduct these second residual risk
reviews under CAA section 112(f). In particular, the EPA is concerned
about the cancer risks posed by the SOCMI source category due to the
EPA's 2016 updated IRIS inhalation URE for EtO, which shows EtO to be
significantly more toxic than previously known.\12\ This updated URE
was not available in 2006, when the EPA conducted its last RTR, but if
this URE had been available, the EPA would almost undoubtedly have
reached different conclusions about risk acceptability and the need to
modify the standards to provide an ample margin of safety to protect
public health. Similarly, for chloroprene, when the EPA conducted the
first residual risk assessment for the SOCMI and Neoprene Production
source categories, there was no inhalation URE for chloroprene.
Therefore, in those risk reviews, the EPA attributed no cancer risk to
chloroprene. The EPA concluded development of the IRIS inhalation URE
for chloroprene in 2010. That URE allows us to assess, for the first
time, the cancer risks posed by chloroprene. Had the EPA had the
benefit of this new URE at the time it conducted the 2006 and 2008
RTRs, the URE would almost undoubtedly have impacted our conclusions
about risk acceptability and the P&R I standards' provision of an ample
margin of safety to protect public health. Instead, we are conducting
that analysis in this action.
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\12\ U.S. EPA. Evaluation of the Inhalation Carcinogenicity of
Ethylene Oxide (CASRN 75-21-8) In Support of Summary Information on
the Integrated Risk Information System (IRIS). December 2016. EPA/
635/R-16/350Fa. Available at: <a href="https://cfpub.epa.gov/ncea/iris/iris_documents/documents/toxreviews/1025tr.pdf">https://cfpub.epa.gov/ncea/iris/iris_documents/documents/toxreviews/1025tr.pdf</a>. See also, 87 FR
77985 (Dec. 21, 2022), Reconsideration of the 2020 National Emission
Standards for Hazardous Air Pollutants: Miscellaneous Organic
Chemical Manufacturing Residual Risk and Technology Review, Final
action; reconsideration of the final rule.
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In order to ensure our standards provide an ample margin of safety
to protect public health following the new IRIS inhalation UREs for EtO
and chloroprene, we are exercising our discretion and conducting risk
assessments in this action for HON sources and for affected sources
producing neoprene subject to the P&R I NESHAP. Finally, we note that
on September 15, 2021, the EPA partially granted a citizen
administrative petition requesting that the EPA conduct a second
residual risk review under CAA section 112(f)(2) for the HON, stating
our intent to conduct a human health risk assessment concurrently with
the section 112(d)(6) review.\13\ Likewise, on March 4, 2022, the EPA
partially granted another citizen administrative petition requesting
that the EPA also conduct a second residual risk review under CAA
section 112(f) for the Neoprene Production source category in the P&R I
NESHAP, stating that we intend to conduct a human health risk
assessment concurrently with the section 112(d)(6) review.\14\ This
final rulemaking is partly undertaken in response to those citizen
administrative petitions. In sum, even though we do not have a
mandatory duty to conduct repeated residual risk reviews under CAA
section 112(f)(2), we have the authority to revisit any rulemaking if
there is: (1) Significant new scientific information suggesting the
public is exposed to higher risks from facilities subject to the HON
and the P&R I and P&R II NESHAP than previously realized, as compared
to the previous risk assessments prepared for earlier rulemakings, or
(2) sufficient evidence that changes within the affected industry are
exposing the public to new risks.
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\13\ See letter dated September 15, 2021, from Joseph Goffman to
Kathleen Riley, Emma Cheuse, and Adam Kron (see Docket Item No. EPA-
HQ-OAR-2022-0730-0047).
\14\ See letter dated March 4, 2022, from Joseph Goffman to Emma
Cheuse, Deena Tumeh, Michelle Mabson, Maryum Jordan, and Dorian
Spence (see Docket Item No. EPA-HQ-OAR-2022-0730-0048).
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2. NSPS
The EPA's authority for the final NSPS rules is CAA section 111,
which governs the establishment of standards of performance for
stationary sources. Section 111(b)(1)(A) of the CAA requires the EPA
Administrator to list categories of stationary sources that in the
Administrator's judgment cause or contribute significantly to air
pollution that may reasonably be anticipated to endanger public health
or welfare. The EPA must then issue performance standards for new (and
modified or reconstructed) sources in each source category pursuant to
CAA section 111(b)(1)(B). These standards are referred to as new source
performance standards, or NSPS. The EPA has the authority to define the
scope of the source categories, determine the pollutants for which
standards should be developed, set the emission level of the standards,
and distinguish among classes, types, and sizes within categories in
establishing the standards.
CAA section 111(b)(1)(B) requires the EPA to ``at least every 8
years review and, if appropriate, revise'' NSPS. However, the
Administrator need not review any such standard if the ``Administrator
determines that such review is not appropriate in light of readily
available information on the efficacy'' of the standard. When
conducting a review of an existing performance standard, the EPA has
the discretion and authority to add emission limits for pollutants or
emission sources not currently regulated for that source category.
In setting or revising a performance standard, CAA section
111(a)(1) provides that performance standards are to reflect ``the
degree of emission limitation achievable through the application of the
BSER which (taking into account the cost of achieving such reduction
and any nonair quality health and environmental impact and energy
requirements) the Administrator determines has been adequately
demonstrated.'' The term ``standard of performance'' in CAA section
111(a)(1) makes clear that the EPA is to determine both the BSER for
the regulated sources in the source category and the degree of emission
limitation achievable through application of the BSER. The EPA must
then, under CAA section 111(b)(1)(B), promulgate standards of
performance for new sources that reflect that level of stringency. CAA
section 111(h)(1) authorizes the Administrator to promulgate ``a
design, equipment, work practice, or operational standard, or
combination thereof'' if in his or her judgment, ``it is not feasible
to prescribe or enforce a standard of performance.'' CAA section
111(h)(2) provides the circumstances under which prescribing or
enforcing a standard of performance is ``not feasible,'' such as, when
the pollutant cannot be emitted through a conveyance designed to emit
or capture the pollutant, or when there is no practicable measurement
methodology for the particular class of sources. CAA section 111(b)(5)
precludes the EPA from prescribing a particular technological system
that must be used
[[Page 42942]]
to comply with a standard of performance. Rather, sources can select
any measure or combination of measures that will achieve the standard.
Pursuant to the definition of new source in CAA section 111(a)(2),
standards of performance apply to facilities that begin construction,
reconstruction, or modification after the date of publication of the
proposed standards in the Federal Register. Under CAA section
111(a)(4), ``modification'' means any physical change in, or change in
the method of operation of, a stationary source which increases the
amount of any air pollutant emitted by such source or which results in
the emission of any air pollutant not previously emitted. Changes to an
existing facility that do not result in an increase in emissions are
not considered modifications. Under the provisions in 40 CFR 60.15,
reconstruction means the replacement of components of an existing
facility such that: (1) The fixed capital cost of the new components
exceeds 50 percent of the fixed capital cost that would be required to
construct a comparable entirely new facility; and (2) it is
technologically and economically feasible to meet the applicable
standards.
In the development of NSPS for the SOCMI source category, the EPA
considered emission sources associated with unit processes, storage and
handling equipment, fugitive emission sources, and secondary sources.
In 1983, the EPA promulgated NSPS for VOC from equipment leaks in SOCMI
(40 CFR part 60, subpart VV). In 1990, the EPA promulgated NSPS (40 CFR
part 60, subparts III and NNN) for VOC from air oxidation unit
processes and distillation operations in the SOCMI (55 FR 26912 and 55
FR 26931). In 1993, the EPA promulgated NSPS (40 CFR part 60, subpart
RRR) for VOC from reactor processes in the SOCMI (58 FR 45948). In
2007, based on its review of NSPS subpart VV, the EPA promulgated
certain amendments to NSPS subpart VV and new NSPS (40 CFR part 60,
subpart VVa) for VOC from certain equipment leaks in the SOCMI (72 FR
64883). This final action presents the required CAA 111(b)(1)(B) review
of the NSPS for the air oxidation unit processes (subpart III),
distillation operations (subpart NNN), reactor processes (subpart RRR),
and equipment leaks (subpart VVa).
3. Petition for Reconsideration
In addition to the final action under CAA section 111(b)(1)(B)
described above, this action includes final amendments to the NSPS
subparts VV and VVa (NSPS for VOC from equipment leaks in SOCMI) based
on its reconsideration of certain aspects of these NSPS subparts that
were raised in an administrative petition which the Agency granted
pursuant to section 307(d)(7)(B) of the CAA. In January 2008, the EPA
received one petition for reconsideration of the NSPS for VOC from
equipment leaks in SOCMI (40 CFR part 60, subparts VV and VVa) and the
NSPS for equipment leaks in petroleum refineries (40 CFR part 60,
subparts GGG and GGGa) pursuant to CAA section 307(d)(7)(B) from the
following petitioners: American Chemistry Council, American Petroleum
Institute (API), and National Petrochemical and Refiners Association
(now the American Fuel and Petrochemical Manufacturers). A copy of the
petition and subsequent EPA correspondence granting reconsideration is
provided in the docket for this rulemaking (see Docket No. EPA-HQ-OAR-
2022-0730). The petitioners primarily requested that the EPA reconsider
four provisions in those rules: (1) The clarification of the definition
of process unit in subparts VV, VVa, GGG, and GGGa; (2) the assignment
of shared storage vessels to specific process units in subparts VV,
VVa, GGG, and GGGa; (3) the monitoring of connectors in subpart VVa;
and (4) the definition of capital expenditure in subpart VVa.\15\ The
rationale for this request is provided in the petition. The petitioners
also requested that the EPA stay the effectiveness of these provisions
of the rule pending resolution of their petition for reconsideration.
On March 4, 2008, the EPA sent a letter to the petitioners informing
them that the EPA was granting their request for reconsideration on
issues (2) through (4) above. The letter also indicated that the EPA
was not taking action on the first issue related to the definition of
process unit. Finally, the letter indicated that the EPA was granting a
90-day stay of the provisions of the rules under reconsideration (see
CAA section 307(d)(7)(B)), as well as the clarification of the
definition of process unit, because of its reliance upon the new
provision on the allocation of shared storage vessels. On June 2, 2008,
the EPA published three actions in the Federal Register relative to
extending the 90-day stay. Specifically, the EPA published a direct
final rule (73 FR 31372) and a parallel proposal (73 FR 31416) in the
Federal Register to extend the stay until we took final action on the
issues of which the EPA granted reconsideration. Under the direct final
rule, the stay would take effect 30 days after the close of the comment
period on the proposed stay if no adverse comments were received. The
third notice published that same day was an interim final rule
extending the 90-day stay at the time for an additional 60 days so that
the stay would not expire before the direct final rule could take
effect (73 FR 31376). The EPA did not receive adverse comments on the
proposed stay and, as a result, the stay became effective August 1,
2008.
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\15\ Note that this final action does not respond to the
petition for reconsideration of NSPS subparts GGG and GGGa, as the
EPA is not reviewing those subparts in this action.
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In the three June 2, 2008 actions, the EPA indicated that it would
be publishing a Federal Register notice in response to the petition;
this action constitutes such notice and formally responds to the issues
raised in the petition with respect to NSPS subparts VV and VVa. This
final action presents the EPA's revisions to the NSPS for VOC from
equipment leaks in SOCMI based on the EPA's reconsideration of issues
(2) through (4) in the petition. We are also finalizing amendments that
address the stay on issue (1) in the petition. See sections III.E and
IV.E of this preamble for details about these final amendments.
B. What are the source categories and how did the previous standards
regulate emissions?
The source categories that are the subject of this final action are
the SOCMI source category subject to the HON and 11 Polymers and Resins
Production source categories subject to the P&R I and P&R II NESHAP.
This final action also addresses equipment leaks in the SOCMI and SOCMI
air oxidation unit processes, distillation operations, and reactor
processes. The NESHAP and NSPS included in this action that regulate
emission sources from the SOCMI and Polymers and Resins Production
source categories are described below.
1. HON
The sources affected by the HON include heat exchange systems and
maintenance wastewater located at SOCMI facilities that are regulated
under NESHAP subpart F; process vents, storage vessels, transfer racks,
and wastewater streams located at SOCMI facilities that are regulated
under NESHAP subpart G; equipment leaks associated with SOCMI processes
regulated under NESHAP subpart H; and equipment leaks from certain non-
SOCMI processes at chemical plants regulated under NESHAP subpart I. As
[[Page 42943]]
previously mentioned, these four NESHAP are more commonly referred
together as the HON.
In general, the HON applies to CMPUs that: (1) Produce one of the
listed SOCMI chemicals,\16\ and (2) either use as a reactant or produce
a listed organic HAP in the process. A CMPU means the equipment
assembled and connected by pipes or ducts to process raw materials and
to manufacture an intended product. A CMPU consists of more than one
unit operation. A CMPU includes air oxidation reactors and their
associated product separators and recovery devices; reactors and their
associated product separators and recovery devices; distillation units
and their associated distillate receivers and recovery devices;
associated unit operations; associated recovery devices; and any feed,
intermediate and product storage vessels, product transfer racks, and
connected ducts and piping. A CMPU includes pumps, compressors,
agitators, PRDs, sampling connection systems, open-ended valves or
lines (OEL), valves, connectors, instrumentation systems, and control
devices or systems. A CMPU is identified by its primary product.
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\16\ See Table 1 to NESHAP subpart F.
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a. NESHAP Subpart F
NESHAP subpart F contains provisions to determine which chemical
manufacturing processes at a SOCMI facility are subject to the HON.
Table 1 of NESHAP subpart F contains a list of SOCMI chemicals, and
Table 2 of NESHAP subpart F contains a list of organic HAP regulated by
the HON. In general, if a process both: (1) Produces one of the listed
SOCMI chemicals and (2) either uses as a reactant or produces a listed
organic HAP in the process, then that SOCMI process is subject to the
HON. Details on how to determine which emission sources (i.e., heat
exchange systems, process vents, storage vessels, transfer racks,
wastewater, and equipment leaks) are part of a chemical manufacturing
process are also contained in NESHAP subpart F. NESHAP subpart F also
contains monitoring requirements for HAP (i.e., HAP listed in Table 4
of NESHAP subpart F) that may leak into cooling water from heat
exchange systems. Additionally, NESHAP subpart F requires sources to
prepare a description of procedures for managing maintenance wastewater
as part of a SSM plan.
b. NESHAP Subpart G
NESHAP subpart G contains the standards for process vents, transfer
racks, storage vessels, and wastewater at SOCMI facilities; it also
includes emissions averaging provisions. NESHAP subpart G provides an
equation representing a site-specific allowable overall emission limit
for the combination of all emission sources subject to the HON at a
SOCMI facility. Existing sources must demonstrate compliance using one
of two approaches: the point-by-point compliance approach or the
emissions averaging approach. New sources are not allowed to use
emissions averaging, but rather must demonstrate compliance using the
point-by-point approach. Under the point-by-point approach, the owner
or operator would apply control to each Group 1 emission source. A
Group 1 emission source is a point which meets the control
applicability criteria, and the owner or operator must reduce emissions
to specified levels; whereas a Group 2 emission source is one that does
not meet the criteria and no additional emission reduction is required.
Under the emissions averaging approach, an owner or operator may elect
to control different groups of emission sources to different levels
than specified by the point-by-point approach, as long as the overall
emissions do not exceed the overall allowable emission level. For
example, an owner or operator can choose not to control a Group 1
emission source (or to control the emission source with a less
effective control technique) if the owner or operator over-controls
another emission source. For the point-by-point approach, NESHAP
subpart G contains the following standards:
<bullet> Group 1 process vents must reduce emissions of organic HAP
using a flare meeting 40 CFR 63.11(b); reduce emissions of total
organic HAP or TOC by 98 percent by weight or to an exit concentration
of 20 ppmv; \17\ or achieve and maintain a TRE index value \18\ greater
than 1.0.\19\
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\17\ The phrase ``whichever is less stringent'' was originally
used as part of this NESHAP standard; however, we have determined
the phrase does not serve any meaningful purpose and are removing it
in this final action. For specific details about this editorial
correction, refer to section 4.3 of the document titled Summary of
Public Comments and Responses for New Source Performance Standards
for the Synthetic Organic Chemical Manufacturing Industry and
National Emission Standards for Hazardous Air Pollutants for the
Synthetic Organic Chemical Manufacturing Industry and Group I & II
Polymers and Resins Industry, which is available in the docket for
this rulemaking.
\18\ See section III.C.3.a of the preamble to the proposed rule
(88 FR 25080, April 25, 2023) for a description of the TRE index
value and how the concept is currently used in the HON.
\19\ Halogenated vent streams (as defined in NESHAP subpart G)
from Group 1 process vents may not be vented to a flare and must
reduce the overall emissions of hydrogen halides and halogens by 99
percent (or 95 percent for control devices installed prior to
December 31, 1992) or reduce the outlet mass emission rate of total
hydrogen halides and halogens to less than 0.45 kg/hr.
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<bullet> Group 1 transfer racks must reduce emissions of total
organic HAP by 98 percent by weight or to an exit concentration of 20
ppmv; \20\ or reduce emissions of organic HAP using a flare meeting 40
CFR 63.11(b), using a vapor balancing system, or by routing emissions
to a fuel gas system or to a process.
---------------------------------------------------------------------------
\20\ See footnote 17.
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<bullet> Group 1 storage vessels must reduce emissions of organic
HAP using a fixed roof tank equipped with an IFR; using an external
floating roof (EFR); using an EFR tank converted to a fixed roof tank
equipped with an IFR; by routing emissions to a fuel gas system or to a
process; or reduce emissions of organic HAP by 95 percent by weight
using a closed vent system (i.e., vapor collection system) and control
device, or combination of control devices (or reduce emissions of
organic HAP by 90 percent by weight using a closed vent system and
control device if the control device was installed before December 31,
1992).
<bullet> Group 1 process wastewater streams and equipment managing
such streams at both new and existing sources must meet control
requirements for: (1) Waste management units including wastewater
tanks, surface impoundments, containers, individual drain systems, and
oil-water separators; (2) treatment processes including the design
steam stripper, biological treatment units, or other treatment devices;
and (3) closed vent systems and control devices such as flares,
catalytic incinerators, etc. Existing sources are not required to meet
control requirements if Group 1 process wastewater streams are included
in a 1 megagram per year source-wide exemption allowed by NESHAP
subpart G.
<bullet> In general, Group 2 emission sources are not required to
apply any additional emission controls (provided they remain below
Group 1 thresholds); however, they are subject to certain monitoring,
reporting, and recordkeeping requirements to ensure that they were
correctly determined to be Group 2 and that they remain Group 2.
c. NESHAP Subpart H
NESHAP subpart H contains the standard for equipment leaks at SOCMI
facilities, including leak detection and repair (LDAR) provisions and
other control requirements. Equipment regulated includes pumps,
compressors, agitators, PRDs, sampling connection
[[Page 42944]]
systems, OEL, valves, connectors, surge control vessels, bottoms
receivers, and instrumentation systems in organic HAP service. A piece
of equipment is in organic HAP service if it contains or contacts a
fluid that is at least 5 percent by weight organic HAP. Depending on
the type of equipment, the standards require either periodic monitoring
for and repair of leaks, the use of specified equipment to minimize
leaks, or specified work practices. Monitoring for leaks must be
conducted using EPA Method 21 in appendix A-7 to 40 CFR part 60 or
other approved equivalent monitoring techniques.
d. NESHAP Subpart I
NESHAP subpart I provides the applicability criteria for certain
non-SOCMI processes subject to the negotiated regulation for equipment
leaks. Regulated equipment is the same as that for NESHAP subpart H.
2. P&R I NESHAP
The P&R I NESHAP generally follows and refers to the requirements
of the HON, with additional requirements for batch process vents.
Generally, the P&R I NESHAP applies to EPPUs and associated equipment.
Similar to a CMPU in the HON, an EPPU means a collection of equipment
assembled and connected by hard-piping or duct work used to process raw
materials and manufacture elastomer product. The EPPU includes unit
operations, recovery operations, process vents, storage vessels, and
equipment that are covered by equipment leak standards and produce one
of the elastomer types listed as an elastomer product, including: butyl
rubber, epichlorohydrin elastomer, ethylene propylene rubber, halobutyl
rubber, Hypalon<SUP>TM</SUP>, neoprene, nitrile butadiene latex,
nitrile butadiene rubber, polybutadiene rubber/styrene butadiene rubber
by solution, polysulfide rubber, styrene butadiene latex, and styrene
butadiene rubber by emulsion. An EPPU consists of more than one unit
operation. An EPPU includes, as ``equipment,'' pumps, compressors,
agitators, PRDs, sampling connection systems, OEL, valves, connectors,
surge control vessels, bottoms receivers, instrumentation systems, and
control devices or systems.
The emissions sources affected by the P&R I NESHAP include heat
exchange systems and maintenance wastewater at P&R I facilities
regulated under NESHAP subpart F; storage vessels, transfer racks, and
wastewater streams at P&R I facilities regulated under NESHAP subpart
G; and equipment leaks at P&R I facilities regulated under NESHAP
subpart H. Process vents are also regulated emission sources but,
unlike the HON, these emissions sources are subdivided into front and
back-end process vents in the P&R I NESHAP. The front-end are unit
operations prior to and including the stripping operations. These are
further subdivided into continuous front-end process vents regulated
under NESHAP subpart G and batch front-end process vents that are
regulated according to the requirements within the P&R I NESHAP. Back-
end unit operations include filtering, coagulation, blending,
concentration, drying, separating, and other finishing operations, as
well as latex and crumb storage. The requirements for back-end process
vents are not subcategorized into batch or continuous and are also
found within the P&R I NESHAP.
3. P&R II NESHAP
The P&R II NESHAP regulates HAP emissions from two source
categories, Epoxy Resins Production (also referred to as BLR) and Non-
Nylon Polyamides Production (also referred to as WSR). The P&R II
NESHAP takes a different regulatory and format approach from the P&R I
NESHAP but still refers to HON provisions for a portion of the
standards. BLR are resins made by reacting epichlorohydrin and
bisphenol A to form diglycidyl ether of bisphenol-A. WSR are polyamide/
epichlorohydrin condensates which are used to increase the tensile
strength of paper products.
The emission sources affected by the P&R II NESHAP are all HAP
emission points within a facility related to the production of BLR or
WSR. These emission points include process vents, storage tanks,
wastewater systems, and equipment leaks. Equipment includes connectors,
pumps, compressors, agitators, PRDs, sampling connection systems, OEL,
and instrumentation system in organic HAP service. Equipment leaks are
regulated under the HON (i.e., NESHAP subpart H).
Process vents, storage tanks, and wastewater systems combined are
regulated according to a production-based emission rate (e.g., pounds
HAP per million pounds BLR or WSR produced). For existing sources, the
rate shall not exceed 130 pounds per 1 million pounds of BLR produced
and 10 pounds per 1 million pounds of WSR produced. For new sources,
BLR requires all uncontrolled emissions to achieve 98 percent reduction
or limits the total emissions to 5,000 pounds of HAP per year. New WSR
sources are limited to 7 pounds of HAP per 1 million pounds of WSR
produced.
4. NSPS Subpart VVa
NSPS subpart VVa contains VOC standards for leaks from equipment
within a process unit for which construction, reconstruction, or
modification commenced after November 7, 2006. Under NSPS subpart VVa,
equipment means each pump, compressor, PRD, sampling connection system,
OEL, valve, and flange or other connector in VOC service and any
devices or systems required by the NSPS. Process units consist of
components assembled to produce, as intermediate or final products, one
or more of the chemicals listed in 40 CFR 60.489. A process unit can
operate independently if supplied with sufficient feed or raw materials
and sufficient storage facilities for the product. The standards in
NSPS subpart VVa include LDAR provisions and other control
requirements. A piece of equipment is in VOC service if it contains or
contacts a fluid that is at least 10 percent by weight VOC. Depending
on the type of equipment, the standards require either periodic
monitoring for and repair of leaks, the use of specified equipment to
minimize leaks, or specified work practices. Monitoring for leaks must
be conducted using EPA Method 21 in appendix A-7 to 40 CFR part 60 or
other approved equivalent monitoring techniques.
5. NSPS Subpart III
NSPS subpart III regulates VOC emissions from SOCMI air oxidation
reactors for which construction, reconstruction, or modification
commenced after October 21, 1983. For the purpose of NSPS subpart III,
air oxidation reactors are devices or process vessels in which one or
more organic reactants are combined with air, or a combination of air
and oxygen, to produce one or more organic compounds. The affected
facility is designated as a single air oxidation reactor with its own
individual recovery system (if any) or the combination of two or more
air oxidation reactors and the common recovery system they share that
produces one or more of the chemicals listed in 40 CFR 60.617 as a
product, co-product, by-product, or intermediate. The BSER for reducing
VOC emissions from SOCMI air oxidation units was identified as
combustion (e.g., incineration, flares) and the standard of performance
requires owners and operators of an affected facility to reduce
emissions of TOC (minus methane and ethane) by 98 percent by weight or
to a concentration of 20 ppmv on a dry basis corrected to
[[Page 42945]]
3 percent oxygen; \21\ combust the emissions in a flare meeting 40 CFR
60.18(b); or maintain a TRE index value \22\ greater than 1.0 without
use of VOC emission control devices.
---------------------------------------------------------------------------
\21\ The phrase ``whichever is less stringent'' was originally
used as part of this NSPS standard; however, we have determined the
phrase does not serve any meaningful purpose and are removing it in
this final action. For specific details about this editorial
correction, refer to section 5.1 of the document titled Summary of
Public Comments and Responses for New Source Performance Standards
for the Synthetic Organic Chemical Manufacturing Industry and
National Emission Standards for Hazardous Air Pollutants for the
Synthetic Organic Chemical Manufacturing Industry and Group I & II
Polymers and Resins Industry, which is available in the docket for
this rulemaking.
\22\ See section III.C.3.b of the preamble to the proposed rule
(88 FR 25080, April 25, 2023) for a description of the TRE index
value and how the concept is used in NSPS subpart III.
---------------------------------------------------------------------------
6. NSPS Subpart NNN
NSPS subpart NNN regulates VOC emissions from SOCMI distillation
operations for which construction, reconstruction, or modification
commenced after December 30, 1983. For the purpose of NSPS subpart NNN,
distillation operations are operations separating one or more feed
stream(s) into two or more exit stream(s), each exit stream having
component concentrations different from those in the feed stream(s);
and the separation is achieved by the redistribution of the components
between the liquid and vapor-phase as they approach equilibrium within
a distillation unit. The affected facility is designated as a single
distillation column with its own individual recovery system (if any) or
the combination of two or more distillation columns and the common
recovery system they share that is part of a process unit that produces
any of the chemicals listed in 40 CFR 60.667 as a product, co-product,
by-product, or intermediate. The BSER for reducing VOC emissions from
SOCMI distillation operations was identified as combustion (e.g.,
incineration, flares) and the standard of performance requires owners
and operators of an affected facility to reduce emissions of TOC (minus
methane and ethane) by 98 percent by weight or to a concentration of 20
ppmv on a dry basis corrected to 3 percent oxygen; \23\ combust the
emissions in a flare meeting 40 CFR 60.18(b); or maintain a TRE index
value \24\ greater than 1.0 without use of VOC emission control
devices.
---------------------------------------------------------------------------
\23\ See footnote 21.
\24\ See section III.C.3.b of the preamble to the proposed rule
(88 FR 25080, April 25, 2023) for a description of the TRE index
value and how the concept is used in NSPS subpart NNN.
---------------------------------------------------------------------------
7. NSPS Subpart RRR
NSPS subpart RRR regulates VOC emissions from SOCMI reactor
processes for which construction, reconstruction, or modification
commenced after June 29, 1990. For the purpose of NSPS subpart RRR,
reactor processes are unit operations in which one or more chemicals,
or reactants other than air, are combined or decomposed in such a way
that their molecular structures are altered and one or more new organic
compounds are formed. The affected facility is designated as a single
reactor process with its own individual recovery system (if any) or the
combination of two or more reactor processes and the common recovery
system they share that is part of a process unit that produces any of
the chemicals listed in 40 CFR 60.707 as a product, co-product, by-
product, or intermediate. The BSER for reducing VOC emissions from
SOCMI reactor processes was identified as combustion (e.g.,
incineration, flares) and the standard of performance requires owners
and operators of an affected facility to reduce emissions of TOC (minus
methane and ethane) by 98 percent by weight or to a concentration of 20
ppmv on a dry basis corrected to 3 percent oxygen; \25\ combust the
emissions in a flare meeting 40 CFR 60.18(b); or maintain a TRE index
value \26\ greater than 1.0 without use of VOC emission control
devices.
---------------------------------------------------------------------------
\25\ See footnote 21.
\26\ See section III.C.3.b of the preamble to the proposed rule
(88 FR 25080, April 25, 2023) for a description of the TRE index
value and how the concept is used in NSPS subpart RRR.
---------------------------------------------------------------------------
C. What changes did we propose in our April 25, 2023, proposal?
1. NESHAP
a. Proposed Actions Related to CAA Section 112(f) Risk Assessment
To reduce risk from the SOCMI source category to an acceptable
level, we proposed under CAA section 112(f) to require (in the HON)
control of EtO emissions from: (1) Process vents, (2) storage vessels,
(3) equipment leaks, (4) heat exchange systems, and (5) wastewater ``in
ethylene oxide service'' (see 88 FR 25080, April 25, 2023, for our
proposed definition of ``in ethylene oxide service''). We also proposed
requirements to reduce EtO emissions from maintenance vents, flares,
and PRDs.
<bullet> For process vents and storage vessels in EtO service, we
proposed owners and operators reduce emissions of EtO by either: (1)
Venting emissions through a closed-vent system to a control device that
reduces EtO by greater than or equal to 99.9 percent by weight, to a
concentration less than 1 ppmv for each process vent and storage
vessel, or to less than 5 lb/yr for all combined process vents; or (2)
venting emissions through a closed-vent system to a flare meeting the
proposed operating and monitoring requirements for flares in NESHAP
subpart F.
<bullet> For equipment leaks in EtO service, we proposed the
following combined requirements: monitoring of connectors in gas/vapor
and light liquid service at a leak definition of 100 ppm on a monthly
basis with no reduction in monitoring frequency and no delay of repair;
light liquid pump monitoring at a leak definition of 500 ppm monthly;
and gas/vapor and light liquid valve monitoring at a leak definition of
100 ppm monthly with no reduction in monitoring frequency and no delay
of repair.
<bullet> For heat exchange systems in EtO service, we proposed to
require owners or operators to conduct more frequent leak monitoring
(weekly instead of quarterly) and repair leaks within 15 days from the
sampling date (in lieu of the current 45-day repair requirement after
receiving results of monitoring indicating a leak), and delay of repair
would not be allowed.
<bullet> For wastewater in EtO service, we proposed to revise the
Group 1 wastewater stream threshold for sources to include wastewater
streams in EtO service.
<bullet> For maintenance vents, we proposed a requirement that
owners and operators cannot release more than 1.0 ton of EtO from all
maintenance vents combined in any consecutive 12-month period.
<bullet> For flares, we proposed a requirement that owners and
operators can send no more than 20 tons of EtO to all of their flares
combined from all HON emission sources at a facility in any consecutive
12-month period.
<bullet> For PRDs in EtO service, we proposed that any atmospheric
PRD release is a violation of the standard.
To reduce risk from the Neoprene Production source category to an
acceptable level, we proposed under CAA section 112(f) to require (in
the P&R I NESHAP) control of chloroprene for: (1) Process vents, (2)
storage vessels, and (3) wastewater ``in chloroprene service'' (see 88
FR 25080, April 25, 2023, for our proposed definition of ``in
chloroprene service''). We also proposed requirements to reduce
chloroprene emissions from maintenance vents and PRDs.
<bullet> For process vents and storage vessels in chloroprene
service, we
[[Page 42946]]
proposed owners and operators reduce emissions of chloroprene by
venting emissions through a closed-vent system to a control device that
reduces chloroprene by greater than or equal to 99.9 percent by weight,
to a concentration less than 1 ppmv for each process vent and storage
vessel, or to less than 5 lb/yr for all combined process vents.
<bullet> For wastewater in chloroprene service, we proposed to
revise the Group 1 wastewater stream threshold for sources to include
wastewater streams in chloroprene service.
<bullet> For maintenance vents, we proposed a requirement that
owners and operators cannot release more than 1.0 ton of chloroprene
from all maintenance vents combined in any consecutive 12-month period.
<bullet> For PRDs in chloroprene service, we proposed that any
atmospheric PRD release is a violation of the standard.
<bullet> We also proposed a facility-wide chloroprene emissions cap
for all neoprene production emission sources as a backstop.
Based on our ample margin of safety analysis, we proposed that the
controls to reduce EtO emissions at HON processes and chloroprene
emissions at neoprene production processes to get risks to an
acceptable level (described in this section of the preamble) would also
provide an ample margin of safety to protect public health. We also
proposed that HAP emissions from the source categories do not result in
an adverse environmental effect, and that it is not necessary to set a
more stringent standard to prevent, taking into consideration costs,
energy, safety, and other relevant factors, an adverse environmental
effect.
b. Proposed Actions Related to CAA Section 112(d)(6) Technology Review
Pursuant to the CAA section 112(d)(6) technology review for the HON
and the P&R I, and P&R II NESHAP, we proposed that no revisions to the
current standards beyond the fenceline monitoring work practice
standard discussed below and those proposed under CAA section 112(f)
are necessary for transfer racks, wastewater streams, and equipment
leaks; however, we did propose additional changes under CAA section
112(d)(6) for heat exchange systems, storage vessels and process vents.
<bullet> For HON and P&R I heat exchange systems, we proposed
requirements that owners or operators must use the Modified El Paso
Method and repair leaks of total strippable hydrocarbon concentration
(as methane) in the stripping gas of 6.2 ppmv or greater. The P&R II
NESHAP currently does not regulate HAP emissions from heat exchange
systems.
<bullet> For HON and P&R I storage vessels, we proposed to revise
applicability thresholds to require existing storage vessels between 38
m\3\ (10,000 gal) and 151 m\3\ (40,000 gal) with a vapor pressure >=6.9
kilopascals to add control, and also require upgraded deck fittings and
controls for guidepoles for all IFR storage vessels. For P&R II storage
vessels, we proposed that no revisions to the current standards are
necessary.
<bullet> For HON and P&R I process vents, we proposed to: (1)
Remove the TRE concept in its entirety; (2) remove 50 ppmv and 0.005
scmm Group 1 process vent thresholds; and (3) redefine a Group 1
process vent (require control) as any process vent that emits >=1.0 lb/
hr of total organic HAP. For P&R II process vents, we proposed that no
revisions to the current standards are necessary.
Under CAA section 112(d)(6), we also proposed a fenceline
monitoring work practice standard requiring owners and operators to
monitor for any of six specific HAP (i.e., benzene, 1,3-butadiene,
ethylene dichloride, vinyl chloride, EtO, and chloroprene) if their
site uses, produces, stores, or emits any of them, and conduct root
cause analysis and corrective action upon exceeding the annual average
concentration action level set forth for each HAP. We also requested
public comments on whether to promulgate the fenceline monitoring work
practice standards, including the proposed action levels for EtO and
chloroprene, under the second step of the CAA section 112(f)(2)
residual risk decision framework to provide an ample margin of safety
to protect public health in light of facility-wide risks.
c. Proposed Actions Related to CAA Section 112(d)(2) and (3), and
112(h)
We proposed other requirements for the HON and P&R I and P&R II
NESHAP based on analyses performed pursuant to CAA sections 112(d)(2)
and (3), and 112(h), and that are consistent with Sierra Club v. EPA,
551 F.3d 1019 (D.C. Cir. 2008), ensuring that CAA section 112 standards
apply continuously, including:
<bullet> new monitoring and operational requirements for flares in
the HON and P&R I NESHAP;
<bullet> work practice standards for periods of SSM for certain HON
and P&R I vent streams (i.e., PRD releases, maintenance vents, and
planned routine maintenance of storage vessels);
<bullet> regulatory provisions for vent control bypasses for
certain HON and P&R I vent streams (i.e., closed vent systems
containing bypass lines);
<bullet> dioxins and furans emission limits in the HON and the P&R
I and P&R II NESHAP;
<bullet> new monitoring requirements for HON and P&R I pressure
vessels;
<bullet> new emission standards for HON & P&R I surge control
vessels and bottoms receivers;
<bullet> a revised applicability threshold for HON transfer racks;
<bullet> requirements in the P&R II NESHAP for heat exchange
systems;
<bullet> requirements in the P&R II NESHAP for WSR sources and
equipment leaks;
<bullet> to require owners and operators that use a sweep, purge,
or inert blanket between the IFR and fixed roof of a storage vessel to
route emissions through a closed vent system and control device;
<bullet> to remove exemptions in the HON and the P&R I and P&R II
NESHAP from the requirement to comply during periods of SSM; and
<bullet> to remove affirmative defense provisions from the P&R I
NESHAP that were adopted in 2011.
d. Other Proposed Actions
In addition to the actions described in the sections above related
to NESHAP, we also proposed:
<bullet> changes to the HON and the P&R I and P&R II NESHAP
recordkeeping and reporting requirements to require the use of
electronic reporting of performance test reports and periodic reports;
<bullet> restructuring of all HON definitions;
<bullet> monitoring requirements for adsorbers that cannot be
regenerated and regenerative adsorbers that are regenerated offsite;
<bullet> to require subsequent performance testing on non-flare
control devices no later than 60 calendar months after the previous
performance test; and
<bullet> to correct section reference errors and make other minor
editorial revisions.
2. NSPS
a. Proposed Actions Related to CAA Section 111(b)(1)(B) Review
Pursuant to the CAA section 111(b)(1)(B) reviews for the SOCMI NSPS
rules, we proposed new NSPS for equipment leaks (NSPS subpart VVb) and
process vents associated with air oxidation units (NSPS subpart IIIa),
distillation operations (NSPS subpart NNNa), and reactor processes
(NSPS subpart RRRa).
<bullet> For NSPS subpart VVb, we proposed the same requirements in
[[Page 42947]]
NSPS subpart VVa plus a requirement that all gas/vapor and light liquid
valves be monitored monthly at a leak definition of 100 ppm and all
connectors be monitored once every 12 months at a leak definition of
500 ppm.
<bullet> For NSPS subparts IIIa, NNNa, and RRRa, we proposed the
same requirements in NSPS subparts III, NNN, and RRR, except we
proposed to: (1) Eliminate the TRE concept in its entirety (including
the removal of the alternative of maintaining a TRE index value greater
than 1 without the use of control device and the limited applicability
exemptions) and instead require owners and operators to reduce
emissions of TOC (minus methane and ethane) from all vent streams of an
affected facility (i.e., SOCMI air oxidation unit processes,
distillation operations, and reactor processes for which construction,
reconstruction, or modification commences after April 25, 2023) by 98
percent by weight or to a concentration of 20 ppmv on a dry basis
corrected to 3 percent oxygen, or combust the emissions in a flare
meeting the same operating and monitoring requirements for flares that
we proposed for flares subject to the HON; (2) eliminate the relief
valve discharge exemption from the definition of ``vent stream'' such
that any relief valve discharge to the atmosphere of a vent stream is a
violation of the emissions standard; (3) require the same work practice
standards for maintenance vents that we proposed for HON process vents;
and (4) require the same monitoring requirements that we proposed for
HON process vents for adsorbers that cannot be regenerated and
regenerative adsorbers that are regenerated offsite.
b. Proposed Actions Related to NSPS Subparts VV and VVa Reconsideration
In response to the January 2008 petition for reconsideration we
proposed: (1) Definitions for ``process unit'' for NSPS subparts VV and
VVa; (2) to remove the requirements in 40 CFR 60.482-1(g) (for NSPS
subpart VV) and 40 CFR 60.482-1a(g) (for NSPS subpart VVa) that are
related to a method for assigning shared storage vessels to specific
process units; (3) to remove the connector monitoring provisions from
NSPS subpart VVa at 40 CFR 60.482-11a in their entirety and instead,
include connector monitoring provisions in NSPS subpart VVb; and (4) to
revise the ``capital expenditure'' definition in NSPS subpart VVa at 40
CFR 60.481a to reflect the definition used in NSPS subpart VV at 40 CFR
60.481 for owners or operators that start a new, reconstructed, or
modified affected source prior to November 16, 2007.
c. Other Proposed Actions
In addition to the actions described in the sections above related
to the CAA section 111(b)(1)(B) reviews for the SOCMI NSPS rules and
the NSPS subparts VV and VVa reconsideration, we also proposed:
<bullet> standards in NSPS subparts VVb, IIIa, NNNa, and RRRa that
apply at all times;
<bullet> the use of electronic reporting of performance test
reports and periodic reports;
<bullet> several corrections to the calibration drift assessment
requirements in NSPS subpart VVa; and
<bullet> to require subsequent performance testing on non-flare
control devices no later than 60 calendar months after the previous
performance test.
III. What is included in this final rule?
This action finalizes the EPA's determinations pursuant to the
applicable provisions of CAA section 112 for the SOCMI source category
and various polymers and resins source categories and amends the HON
and P&R I and P&R II NESHAP based on those determinations. In addition,
this action finalizes determinations of our review of the SOCMI NSPS
rules pursuant to CAA section 111(b)(1)(B). This actions also finalizes
other changes to the NESHAP, including adding requirements and
clarifications for periods of SSM and bypasses; revising the operating
and monitoring requirements for flares; adding provisions for
electronic reporting; and other editorial and technical changes.
Additionally, this action finalizes amendments to NSPS subparts VV and
VVa in response to the January 2008 petition for reconsideration. This
action also reflects several changes to the April 25, 2023 proposal (88
FR 25080), in consideration of comments received during the public
comment period as described in section IV of this preamble.
A. What are the final rule amendments based on the risk review for the
SOCMI and Neoprene Production source categories NESHAP?
Consistent with the proposal, the EPA determined that the risks for
the SOCMI and Neoprene Production source categories under the previous
MACT standards are unacceptable. When risks are unacceptable, the EPA
must determine the emissions standards necessary to reduce risk to an
acceptable level. As such, the EPA is promulgating final amendments to
the HON pursuant to CAA section 112(f)(2) that require control of EtO
for: (1) Process vents, (2) storage vessels, (3) equipment leaks, (4)
heat exchange systems, and (5) wastewater ``in ethylene oxide
service.'' We are also finalizing requirements to reduce EtO emissions
from maintenance vents and PRDs. As discussed in section IV.A of this
preamble, implementation of these controls will reduce risk to an
acceptable level and provide an ample margin of safety to protect
public health from source category emissions points. In addition, the
fenceline monitoring requirements being finalized in this action will
further reduce whole-facility EtO and chloroprene emissions at
facilities with HON and Neoprene Production processes, with
consequential reductions in risks from these pollutants. In general, we
are finalizing all of the EtO related requirements as proposed (for
HON), except: we are not finalizing (in response to persuasive comments
received during the public comment period) the proposed requirement at
40 CFR 63.108(p) that would prohibit owners and operators from sending
more than 20 tons of EtO to all of their flares combined in any
consecutive 12-month period. In addition to the primary CAA section
112(d)(6)-based fenceline monitoring program action levels that we are
finalizing for all six HAP that reflect compliance with the source
category-specific emissions limits for SOCMI and P&R I source category
processes (see section III.B.1 of this preamble), we are also
finalizing separately, in the P&R I NESHAP for Neoprene Production
sources, an additional secondary action level under CAA section
112(f)(2) for fenceline monitoring of chloroprene emissions. This
secondary action level for chloroprene for facilities with Neoprene
Production sources is the same action level that was proposed. The
primary chloroprene action level, which applies to sources subject to
40 CFR subpart H in the HON, is higher than what was proposed, but
reflects the modeled emissions concentrations expected to result from
compliance with the other emission standards adopted in the final rule,
as we discussed in the proposed rule. See 88 FR at 25145/col. 2. The
secondary chloroprene action level will further reduce whole-facility
risks caused by such emissions from facilities with Neoprene Production
sources, consistent with the goal to provide an ample margin of safety
to protect public health. For this reason, for facilities with Neoprene
Production sources we are promulgating the secondary chloroprene action
level we had proposed under CAA section 112(d)(6)
[[Page 42948]]
under our CAA section 112(f)(2) authority, as we requested comment on
in the proposed rule. See id., at 25145/col. 3.
Also, based on comments received on the proposed rulemaking, we are
clarifying in this final action that:
<bullet> we mean ``the procedures specified in Sec. 63.109''
instead of ``sampling and analysis'' within the definitions of ``in
ethylene oxide service'' for storage vessels, equipment leaks, and heat
exchange systems (see 40 CFR 63.101);
<bullet> the sampling site for determining whether an emissions
source is in EtO service is after the last recovery device (if any
recovery devices are present) but prior to the inlet of any control
device that is present and prior to release to the atmosphere (see 40
CFR 63.109(a));
<bullet> owners and operators can use good engineering judgment to
determine the percent of EtO of the process fluid cooled by the heat
exchange system similar to what we are allowing for equipment leaks in
40 CFR 63.109(c)(2) (see 40 CFR 63.109(e));
<bullet> the 5 lb/yr EtO mass threshold for combined process vents
in EtO service is on a CMPU-by-CMPU basis (see 40 CFR 63.113(j)(2), 40
CFR 63.124(a)(4) and (a)(4)(iii), and within the definition of ``in
ethylene oxide service'' for process vents);
<bullet> owners and operators may delay repair of equipment leaks
in EtO service, and heat exchange systems in EtO service, indefinitely
as long as there is no longer an active EtO leak once the equipment is
isolated and not in EtO service (see 40 CFR 63.104(h)(6) and 40 CFR
63.171(b));
<bullet> we mean ``process wastewater'' instead of ``wastewater''
in 40 CFR 63.132(c)(1)(iii) and (d)(1)(ii);
<bullet> owners and operators can demonstrate compliance with the
standards for wastewater in EtO service if the concentration of EtO is
reduced, by removal or destruction, to a level less than 1 ppmw as
determined in the procedures specified in 40 CFR 63.145(b) (see 40 CFR
63.138(b)(3) and (c)(3)); and
<bullet> owners and operators can use test methods specified in 40
CFR 63.109(d) for analysis of EtO in wastewater (see 40 CFR
63.144(b)(5)(i)).
Additionally, the EPA is promulgating final amendments to the P&R I
NESHAP for Neoprene Production sources pursuant to CAA section
112(f)(2) that require control of chloroprene for: (1) Process vents,
(2) storage vessels, (3) wastewater ``in chloroprene service.'' We are
also finalizing requirements to reduce chloroprene emissions from
maintenance vents and PRDs. As discussed in section IV.A of this
preamble, implementation of these controls will reduce risk to an
acceptable level and provide an ample margin of safety to protect
public health from the Neoprene Production source category. In general,
we are finalizing all of the chloroprene related requirements as
proposed (for Neoprene Production sources in the P&R I NESHAP), except
in response to persuasive comments received during the public comment
period: (1) We are not finalizing the facility-wide chloroprene
emissions cap at 40 CFR 63.483(a)(10) that would prohibit owners and
operators from emitting 3.8 tpy of chloroprene in any consecutive 12-
month period from all neoprene production emission sources; (2) we are
revising the performance standard from a 99.9 percent by weight
reduction requirement to a 98 percent by weight reduction requirement
for storage vessels in chloroprene service (see 40 CFR 63.484(u) and 40
CFR 53.510), continuous front-end process vents in chloroprene service
(see 40 CFR 63.485(y) and 40 CFR 53.510), and batch front-end process
vents in chloroprene service (see 40 CFR 63.487(j)); (3) we are
finalizing a requirement that owners and operators reduce emissions of
chloroprene from back-end process vents in chloroprene service at
affected sources producing neoprene by venting emissions through a
closed-vent system to a non-flare control device that reduces
chloroprene by greater than or equal to 98 percent by weight, to a
concentration less than 1 ppmv for each process vent, or to less than 5
lb/yr for all combined process vents (see 40 CFR 63.494(a)(7)); and (4)
we are finalizing in the primary CAA section 112(d)(6)-based fenceline
monitoring program action levels for all six HAP addressed in the
proposal that reflect compliance with the source category-specific
emissions limits for SOCMI and P&R I source category processes, and
which subject sources are largely already meeting (see section III.B.1
of this preamble). Separately, we are also setting an additional
secondary action level under CAA section 112(f)(2) for fenceline
monitoring of chloroprene emissions. This standard will further reduce
whole-facility risks caused by such emissions, consistent with the goal
to provide an ample margin of safety to protect public health. Also,
based on comments received on the proposed rulemaking, we are
clarifying in this final action that:
<bullet> we mean ``the procedures specified in Sec. 63.509''
instead of ``sampling and analysis'' within the definitions of ``in
chloroprene service'' for storage vessels (see 40 CFR 63.482);
<bullet> the sampling site for determining whether an emissions
source is in chloroprene service is after the last recovery device (if
any recovery devices are present) but prior to the inlet of any control
device that is present and prior to release to the atmosphere (see 40
CFR 63.509(a)); and
<bullet> the 5 lb/yr chloroprene mass threshold for combined
process vents in chloroprene service is on a EPPU-by-EPPU basis (see
the definition of ``in chloroprene service'' for process vents).
Section IV.A.3 of this preamble provides a summary of key comments
we received on the CAA section 112(f) provisions and our responses.
B. What are the final rule amendments based on the technology review
for the SOCMI, P&R I, and P&R II source categories NESHAP pursuant to
CAA section 112(d)(6) and NSPS reviews for the SOCMI source category
pursuant to CAA section 111(b)(1)(B)?
1. NESHAP
For transfer racks, wastewater streams, and equipment leaks in the
SOCMI, P&R I, and P&R II source categories, the EPA is finalizing its
proposed determination in the technology review that there are no
developments in practices, processes, and control technologies that
warrant revisions to the MACT standards beyond those needed under CAA
section 112(f) or for other purposes besides section 112(d)(6).
Therefore, with the exception of the fenceline monitoring standards
that are discussed further below, we are not finalizing revisions to
the MACT standards for these emission sources under CAA section
112(d)(6).
For heat exchange systems, we determined that there are
developments in practices, processes, and control technologies that
warrant revisions to the MACT standards for heat exchange systems in
the SOCMI, P&R I, and P&R II source categories. Therefore, to satisfy
the requirements of CAA section 112(d)(6), we are revising the MACT
standards, consistent with the proposed rule (88 FR 25080, April 25,
2023), to include revisions to the heat exchange system requirements to
require owners or operators to use the Modified El Paso Method and
repair leaks of total strippable hydrocarbon concentration (as methane)
in the stripping gas of 6.2 ppmv or greater. We are also finalizing, as
proposed, that owners and operators may use the current leak monitoring
requirements for heat exchange systems at 40 CFR 63.104(b) in lieu of
using the Modified El Paso Method provided that 99 percent by weight or
more of the
[[Page 42949]]
organic compounds that could leak into the heat exchange system are
water soluble and have a Henry's Law Constant less than 5.0E-6
atmospheres-cubic meters/mol at 25 degrees Celsius. See 40 CFR
63.104(g) through (j) and (l) (for HON), 40 CFR 63.502(n)(7) (for the
P&R I NESHAP), and 40 CFR 63.523(d) and 40 CFR 63.524(c) (for the P&R
II NESHAP).
For storage vessels, we did not identify any control options for
storage tanks subject to the P&R II NESHAP. However, we determined that
there are developments in practices, processes, and control
technologies that warrant revisions to the MACT standards for storage
vessels in the SOCMI and P&R I source categories. Therefore, to satisfy
the requirements of CAA section 112(d)(6), we are revising the MACT
standards, consistent with the proposed rule (88 FR 25080, April 25,
2023), to include revisions to the storage vessel applicability
threshold to require both existing and new storage vessels between 38
m\3\ and 151 m\3\ with a vapor pressure greater than or equal to 6.9
kilopascals to reduce emissions of organic HAP by 95 percent utilizing
a closed vent system and control device, or reduce organic HAP
emissions either by utilizing an IFR, an EFR, or by routing the
emissions to a process or a fuel gas system, or vapor balancing. We are
also finalizing, as proposed, requirements that all openings in an IFR
(except those for automatic bleeder vents (vacuum breaker vents), rim
space vents, leg sleeves, and deck drains) be equipped with a deck
cover; and that the deck cover be equipped with a gasket between the
cover and the deck; and control requirements for guidepoles for all
storage vessels equipped with an IFR. See Tables 5 and 6 to subpart G,
and 40 CFR 63.119(b)(5)(ix), (x), (xi), and (xii) (for HON) and 40 CFR
63.484(t) (for the P&R I NESHAP).
For process vents, we did not identify any control options for
process vents subject to the P&R II NESHAP. However, we determined that
there are developments in practices, processes, and control
technologies that warrant revisions to the MACT standards for process
vents in the SOCMI and P&R I source categories. Therefore, to satisfy
the requirements of CAA section 112(d)(6), we are revising the MACT
standards, consistent with the proposed rule (88 FR 25080, April 25,
2023), to include revisions to the process vent applicability threshold
to redefine a HON Group 1 process vent and P&R I Group 1 continuous
front-end process vent (i.e., to require control) as any process vent
that emits greater than or equal to 1.0 lb/hr of total organic HAP. We
are also removing, as proposed, the TRE concept in its entirety, and
removing, as proposed, the 50 ppmv and 0.005 scmm Group 1 process vent
thresholds. See 40 CFR 63.101 and 40 CFR 63.113(a)(1), (2), and (4)
(for HON) and 40 CFR 63.482 and 40 CFR 63.485(l)(6), (o)(6), (p)(5),
and (x) (for the P&R I NESHAP). To satisfy the requirements of CAA
section 112(d)(6), we are also revising the MACT standards, consistent
with the proposed rule (88 FR 25080, April 25, 2023), to include
revisions to the process vent applicability threshold to redefine a P&R
I Group 1 batch front-end process vent as process vents that release
total annual organic HAP emissions greater than or equal to 4,536 kg/yr
(10,000 lb/yr) from all batch front-end process vents combined. See 40
CFR 63.482, 40 CFR 63.487(e)(1)(iv), 40 CFR 63.488(d)(2), (e)(4),
(f)(2), and (g)(3) (for the P&R I NESHAP).
Also, to satisfy the requirements of CAA section 112(d)(6), we are
revising the MACT standards, consistent with the proposed rule (88 FR
25080, April 25, 2023), to include a fenceline monitoring work practice
standard for the SOCMI and P&R I source categories, requiring owners
and operators to monitor for any of six specific HAP (i.e., benzene,
1,3-butadiene, ethylene dichloride, vinyl chloride, EtO, and
chloroprene) if their affected source uses, produces, stores, or emits
any of them, and to conduct root cause analysis and corrective action
upon exceeding the annual average concentration action level set forth
for each HAP. However, based on comments received on the proposed
rulemaking, we are amending the fenceline monitoring work practice
standards in the final rule adopted under CAA section 112(d)(6) to
include the action level of 0.8 ug/m\3\ for chloroprene, which reflects
compliance with the source category-specific emissions limits for P&R I
source category processes. The action levels for benzene, 1,3-
butadiene, ethylene dichloride, EtO, and vinyl chloride will also
correspond to the modeled concentrations resulting from compliance with
the process emission standards promulgated in the final rule and/or
levels that HON-subject sources are largely already meeting.
Separately, we are also setting an additional secondary action level of
0.3 ug/m\3\ for chloroprene under CAA section 112(f)(2), because this
standard will further reduce elevated risks from facility-wide
emissions of this pollutant consistent with the goal to provide an
ample margin of safety to protect public health. See 40 CFR 63.184 (for
HON) and 40 CFR 63.502 (for the P&R I NESHAP). In addition, the final
rule includes burden reduction measures to allow owners and operators
to skip fenceline measurement periods for specific monitors with a
history of measurements that are at or below certain specified action
levels. We have also made a clarification that fenceline monitoring is
required for owners and operators with affected sources that produce,
store, or emit one or more of the target analytes; and we have reduced
the requirements in the final rule for the minimum detection limit of
alternative measurement approaches (for fenceline monitoring). In
addition, we have made clarifications on the calculation of delta c
([Delta]c) \27\ when a site-specific monitoring plan is used to correct
monitoring location concentrations due to offsite impacts, and we have
made a change in the required method detection limit for alternative
test methods from an order of magnitude below the action level to one-
third of the action level. Finally, with the exception of fenceline
monitoring of chloroprene at P&R I affected sources producing neoprene,
discussed below, we have changed the compliance date to begin fenceline
monitoring from 1 to 2 years after the effective date of the final
rule. For P&R I affected sources producing neoprene, we have changed
the compliance date for fenceline monitoring of chloroprene to begin no
later than October 15, 2024, or upon startup, whichever is later,
subject to the owner or operator seeking the EPA's authorization of an
extension of up to 2 years from July 15, 2024.
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\27\ Delta c, notated as [Delta]c, represents the concentration
difference between the highest measured concentration and lowest
measured concentration for a set of samples in one sampling period.
The sampling period [Delta]c values are averaged over 1 year to
create an annual average; the annual average [Delta]c is compared to
the action level.
---------------------------------------------------------------------------
Section III.G.1 of this preamble provides a more detailed
discussion of the effective and compliance dates for the requirements
we are finalizing in this action for the HON and the P&R I NESHAP.
Section IV.B.3 of this preamble provides a summary of key comments we
received on the CAA section 112(d)(6) provisions and our responses.
2. NSPS
The EPA is finalizing, as proposed, a determination that the BSER
for reducing VOC emissions from SOCMI air oxidation units, distillation
operations, and reactor processes remains combustion (e.g.,
incineration, flares), and we are also maintaining that the standard of
performance of 98
[[Page 42950]]
percent reduction of TOC (minus methane and ethane), or reduction of
TOC (minus methane and ethane) to an outlet concentration of 20 ppmv on
a dry basis corrected to 3 percent oxygen, continues to reflect the
BSER for NSPS subparts IIIa, NNNa, and RRRa. While we are finalizing no
changes in the BSER for reducing VOC emissions from SOCMI air oxidation
units, distillation operations, and reactor processes, we determined
that there are certain advances in process operations that were not
identified or considered during development of the original NSPS
subparts III, NNN, and RRR (for SOCMI air oxidation units, distillation
operations, and reactor processes, respectively), which warrant
revisions to the requirements for process vents in the SOCMI source
category. Therefore, pursuant to CAA section 111(b)(1)(B), we are
finalizing revised process vent requirements in new NSPS subparts IIIa,
NNNa, and RRRa (for SOCMI air oxidation unit processes, distillation
operations, and reactor processes for which construction,
reconstruction, or modification commenced after April 25, 2023),
consistent with the proposed rule (88 FR 25080, April 25, 2023). In
particular, we are finalizing for NSPS subparts IIIa, NNNa and RRRa, as
proposed, the removal of the entire TRE concept (including the removal
of the alternative of maintaining a TRE index value greater than 1
without the use of control device and the limited applicability
exemptions) such that owners and operators of affected facilities (for
which construction, reconstruction, or modification commences after
April 25, 2023) are required to reduce emissions of TOC (minus methane
and ethane) from all vent streams of an affected facility by 98 percent
by weight or to a concentration of 20 ppmv on a dry basis corrected to
3 percent oxygen, or combust the emissions in a flare. The EPA is also
finalizing, as proposed, that affected sources that combust the
emissions in a flare meet the same operating and monitoring
requirements for flares that we are finalizing for flares subject to
the HON. However, based on comments received on the proposed
rulemaking, we are finalizing a mass-based exemption criteria of 0.001
lb/hr TOC (for which emission controls are not required) in new NSPS
subparts IIIa and NNNa. Also, as proposed, we are not including in the
final NSPS subparts IIIa, NNNa, and RRRa a relief valve discharge
exemption in the definition of ``vent stream''; instead, any relief
valve discharge to the atmosphere of a vent stream is a violation of
the emissions standard. In addition, we are finalizing, as proposed,
the same work practice standards for maintenance vents that we are
finalizing for HON process vents, and, as proposed, the same monitoring
requirements that we are finalizing for HON process vents for adsorbers
that cannot be regenerated and regenerative adsorbers that are
regenerated offsite.
For equipment leaks, we determined that there are techniques used
in practice related to LDAR of certain equipment that achieve greater
emission reductions than those currently required by NSPS subpart VVa.
Therefore, pursuant to the requirements of CAA section 111(b)(1)(B), we
are finalizing revised equipment leak requirements in new NSPS subpart
VVb (for facilities that commence construction, reconstruction, or
modification after April 25, 2023), consistent with the proposed rule
(88 FR 25080, April 25, 2023). We are finalizing that BSER for gas and
light liquid valves is the same monitoring in an LDAR program as NSPS
subpart VVa, but now at a leak definition of 100 ppm, and BSER for
connectors is monitoring in the LDAR program at a leak definition of
500 ppm and monitored annually, with reduced frequency for good
performance. In a change from the proposed rule, we are finalizing a
definition of ``capital expenditure'' in NSPS subpart VVb to use a
formula that better reflects the trajectory of inflation.
Section IV.B.3 of this preamble provides a summary of key comments
we received on the proposed provisions pursuant to CAA section
111(b)(1)(B) and our responses.
C. What are the final rule amendments pursuant to CAA sections
112(d)(2) and (3), and 112(h) for the SOCMI, P&R I, and P&R II source
categories?
Consistent with Sierra Club v. EPA 551 F. 3d 1019 (D.C. Cir. 2008)
and the April 25, 2023, proposal (88 FR 25080), we are revising
monitoring and operational requirements for flares to ensure HON and
P&R I flares meet the MACT standards at all times when controlling HAP
emissions.\28\ See 40 CFR 63.108 (for HON) and 40 CFR 63.508 (for the
P&R I NESHAP). In addition, we are finalizing provisions and
clarifications as proposed for periods of SSM and bypasses, including:
---------------------------------------------------------------------------
\28\ P&R II sources do not use flares as APCDs as they are
making resins from chlorinated chemicals (i.e., epichlorohydrin
feedstocks), and chlorinated chemicals are not controlled with
flares.
---------------------------------------------------------------------------
<bullet> PRD releases (see 40 CFR 63.165(e) (for HON) and 40 CFR
63.502(a) (for the P&R I NESHAP));
<bullet> bypass lines on closed vent systems (see 40 CFR
63.114(d)(3), 40 CFR 63.118(a)(5), 40 CFR 63.127(d)(3), 40 CFR
63.130(a)(2)(iv), (b)(3), and (d)(7), and 40 CFR 63.148(f)(4),
(i)(3)(iii), and (j)(4) (for HON and the P&R I NESHAP) as well as 40
CFR 63.480(d)(3), 40 CFR 63.491(e)(6), 40 CFR 63.497(d)(3), and
63.498(d)(5)(v) (for the P&R I NESHAP));
<bullet> maintenance vents and equipment openings (excluding
storage vessel degassing) (see 40 CFR 63.113(k) (for HON) 40 CFR
63.485(x) and 40 CFR 63.487(i) (for the P&R I NESHAP));
<bullet> storage vessel degassing (see 40 CFR 63.119(a)(2) (for
HON) and 40 CFR 63.484(a) (for the P&R I NESHAP)); and
<bullet> planned routine maintenance for storage vessels (see 40
CFR 63.119(e)(3) through (5) (for HON) and 40 CFR 63.484(a) (for the
P&R I NESHAP)).
However, in response to comments received on the proposed
rulemaking for storage vessel degassing, we are: (1) Clarifying in the
final rule at 40 CFR 63.119(a)(6) that the storage vessel degassing
work practice standard applies to all Group 1 storage vessels,
including storage vessels in EtO service, and (2) revising the storage
vessel degassing work practice standard in the final rule at 40 CFR
63.119(a)(6) to allow storage vessels to be vented to the atmosphere
once a storage vessel degassing organic HAP concentration of 5,000 ppmv
as methane is met, or until the vapor space concentration is less than
10 percent of the LEL. In addition, in response to comments received on
the proposed rulemaking for planned routine maintenance of storage
vessels, we are clarifying in the final rule at 40 CFR 63.119(f)(3)
that the 240-hour planned routine maintenance provisions also apply for
breathing losses for fixed rood roof vessels routed to a fuel gas
system or to a process.
To address regulatory gaps, we are also finalizing the emission
limits as proposed for polychlorinated dibenzo-p-dioxins (dioxins) and
polychlorinated dibenzofurans (furans) for HON, P&R I, and P&R II
facilities (see 40 CFR 63.113(a)(5) (for HON), 40 CFR 63.485(x) and 40
CFR 63.487(a)(3) and (b)(3) (for the P&R I NESHAP), and 40 CFR
63.523(e), 40 CFR 63.524(a)(3), and 40 CFR 63.524(b)(3) (for the P&R II
NESHAP)). We are also finalizing the requirements as proposed for
transfer operations (see 40 CFR 63.101 (for HON)), heat exchange
systems (40 CFR 63.523(d) and 40 CFR 63.524(c) (for the P&R II
NESHAP)), and WSR sources and equipment leaks (see 40 CFR 63.524(a)(3)
and (b)(3) (for the P&R II NESHAP)). In addition, we are finalizing the
requirements as proposed for pressure vessels (see 40 CFR 63.119(a)(7)
(for HON) and 40 CFR 63.484(t) (for the P&R I NESHAP)), surge
[[Page 42951]]
control and bottoms receivers (see 40 CFR 63.170(b) (for HON) and 40
CFR 63.485(d) (for the P&R I NESHAP)), but with a few changes in the
final rule in response to persuasive comments received during the
public comment period.
In response to comments received on the proposed rulemaking for
pressure vessels, we are:
<bullet> clarifying that the pressure vessel requirements at 40 CFR
63.119(a)(7) only apply to pressure vessels that are considered Group 1
storage vessels;
<bullet> clarifying that if the equipment is not a connector, gas/
vapor or light liquid valve, light liquid pump, or PRD in ETO service
and the equipment is on a pressure vessel located at a HON or P&R I
facility, then that particular equipment is not subject to HON subpart
H, but rather the equipment is subject to the pressure vessel
requirements we proposed and are finalizing in 40 CFR 63.119(a)(7);
<bullet> clarifying that unsafe and difficult/inaccessible to
monitor provisions in 40 CFR 63.168(h) and (i) (for valves in gas/vapor
service and in light liquid service) and in 40 CFR 63.174(f) and (h)
(for connectors in gas/vapor service and in light liquid service) still
apply to valves and connectors when complying with 40 CFR 63.119(a)(7);
and
<bullet> replacing the word ``deviation'' with ``violation'' in the
final rule text at 40 CFR 63.119(a)(7).
In response to comments received on the proposed rulemaking for
surge control and bottoms receivers, we are adding language in the
``C'' and ``Q'' terms of the equations at 40 CFR 63.115(g)(3)(ii) and
(g)(4)(iv) to allow the use of engineering calculations to determine
concentration or flow rate only in situations where measurements cannot
be taken with EPA reference methods. We are also adding reference
methods for measuring flow rate at 40 CFR 63.115(g)(3)(ii) and 40 CFR
63.115(g)(4)(iv).
Finally, we are finalizing, as proposed, that owners and operators
that use a sweep, purge, or inert blanket between the IFR and fixed
roof of a storage vessel are required to route emissions through a
closed vent system and control device (see 40 CFR 63.119(b)(7)).
However, based on comments received on the proposed rulemaking, we are
clarifying in the final rule that 40 CFR 63.119(b)(7) applies only if a
continuous sweep, purge, or inert blanket is used between the IFR and
fixed roof that causes a pressure/vacuum vent to remain continuously
open to the atmosphere where uncontrolled emissions are greater than or
equal to 1.0 lb/hr of total organic HAP.
Section IV.C.3 of this preamble provides a summary of key comments
we received on the CAA sections 112(d)(2), (d)(3), and (h) provisions
and our responses.
D. What are the final rule amendments addressing emissions during
periods of SSM?
1. NESHAP
We are finalizing the proposed amendments to the HON and the P&R I
and P&R II NESHAP to remove and revise provisions related to SSM. In
its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir.
2008), the Court vacated portions of two provisions in the EPA's CAA
section 112 regulations governing the emissions of HAP during periods
of SSM. Specifically, the Court vacated the SSM exemptions contained in
40 CFR 63.6(f)(1) and (h)(1), holding that under section 302(k) of the
CAA, emissions standards or limitations must be continuous in nature,
and that the SSM exemptions violated the CAA's requirement that some
CAA section 112 standards apply at all times. We are finalizing, as
proposed, a requirement that the standards apply at all times (see 40
CFR 63.102(e) (for HON) and 40 CFR.525(j) (for the P&R II NESHAP)),
consistent with the Sierra Club decision. We determined that facilities
in the SOCMI and P&R II source categories can meet the applicable MACT
standards at all times, including periods of startup and shutdown. We
note that on April 21, 2011 (see 77 FR 22566), the EPA finalized
amendments to eliminate the SSM exemption in the P&R I NESHAP; however,
for consistency with the SSM-related amendments that we are finalizing
for the HON and the P&R II NESHAP, we are also finalizing, as proposed,
additional amendments to the P&R I NESHAP related to the SSM exemption
that were not addressed in the April 21, 2011, P&R I rule.
As discussed in the proposal preamble, the EPA interprets CAA
section 112 as not requiring emissions that occur during periods of
malfunction to be factored into development of CAA section 112
standards, although the EPA has the discretion to set standards for
malfunction periods where feasible. Where appropriate, and as discussed
in section III.C of this preamble, we are also finalizing alternative
standards for certain emission points during periods of SSM to ensure a
CAA section 112 standard applies ``at all times.'' Other than for those
specific emission points discussed in section III.C of this preamble,
the EPA determined that no additional standards are needed to address
emissions during periods of SSM and that facilities in the SOCMI and
P&R II source categories can meet the applicable MACT standards at all
times, including periods of startup and shutdown.
We are also finalizing, as proposed, revisions to the HON and P&R
II General Provisions tables (Table 3 to subpart F of part 63 and Table
1 to subpart W of part 63, respectively) to eliminate requirements that
include rule language providing an exemption for periods of SSM. We
note that the EPA already made a similar revision to the General
Provisions table to the P&R I NESHAP (see 77 FR 22566, April 21, 2011).
Additionally, we are finalizing our proposal to eliminate language
related to SSM that treats periods of startup and shutdown the same as
periods of malfunction. Finally, we are finalizing our proposal to
revise reporting and recordkeeping requirements for deviations as they
relate to exemptions for periods of SSM. These revisions are consistent
with the requirement in 40 CFR 63.102(e) and 40 CFR.525(j) that the
standards apply at all times. We are also finalizing, as proposed, a
revision to the performance testing requirements. The final performance
testing provisions prohibit performance testing during SSM because
these conditions are not representative of normal operating conditions.
The final rule also requires, as proposed, that operators maintain
records to document that operating conditions during the test represent
normal operations. In light of NRDC v. EPA, 749 F.3d 1055 (D.C. Cir.,
2014) (vacating affirmative defense provisions in the CAA section 112
rule establishing emission standards for Portland cement kilns), the
EPA is also removing, as proposed, all of the regulatory affirmative
defense provisions from the P&R I NESHAP at 40 CFR 480(j)(4) in its
entirety and all other rule text that references these provisions
(i.e., the definition of affirmative defense in 40 CFR 63.482(b) and
the reference to ``Sec. [thinsp]63.480(j)(4)'' in 40 CFR
63.506(b)(1)(i)(A) and (b)(1)(i)(B)); and we did not receive any
comments in opposition to these amendments.
The legal rationale and detailed revisions for SSM periods and the
affirmative defense provision that we are finalizing here are set forth
in the proposal preamble (see 88 FR 25080, April 25, 2023).
2. NSPS
The EPA has determined the reasoning in the court's decision in
Sierra Club applies equally to CAA
[[Page 42952]]
section 111 because the definition of ``emission'' or ``standard'' in
CAA section 302(k), and the embedded requirement for continuous
standards, also applies to the NSPS.\29\ Therefore, we are finalizing,
as proposed, standards in NSPS subparts VVb, IIIa, NNNa, and RRRa that
apply at all times, and more specifically during periods of SSM. The
NSPS general provisions in 40 CFR 60.8(c) currently exempt non-opacity
emission standards during periods of SSM. We are finalizing, as
proposed, specific requirements in NSPS subparts IIIa, NNNa, and RRRa
that override the general provisions for SSM (see 40 CFR 60.612a, 40
CFR 60.662a, and 40 CFR 60.702a, respectively).
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\29\ See, e.g., 88 FR 11556 (Feb. 23, 2023) (removing SSM
exemptions from NSPS for lead acid battery manufacturing plants); 88
FR 80594 (Nov. 20, 2023) (removing SSM exemptions from NSPS for
secondary lead smelters); 77 FR 49490 (Aug. 16, 2012) (removing SSM
exemptions from NSPS for oil and natural gas sector).
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E. What are the final amendments addressing the NSPS Subparts VV and
VVa reconsideration?
In response to the January 2008 petition for reconsideration, we
are finalizing, as proposed: (1) Definitions for ``process unit'' for
NSPS subparts VV and VVa; (2) removal of the requirements in 40 CFR
60.482-1(g) (for NSPS subpart VV) and 40 CFR 60.482-1a(g) (for NSPS
subpart VVa) that are related to a method for assigning shared storage
vessels to specific process units; and (3) removal of the connector
monitoring provisions from NSPS subpart VVa at 40 CFR 60.482-11a in
their entirety. However, based on comments received on the proposed
rulemaking, we are revising the value of ``X'' in the capital
expenditure equation of NSPS subpart VVa to correct an erroneous
phrasing that attached the value of ``X'' in the percent Y equation to
the date of construction, reconstruction and modification (as opposed
to date of physical or operational change). In the final rule, we have
revised the ``capital expenditure'' definition in NSPS subpart VVa at
40 CFR 60.481a such that for owners or operators that made a physical
or operational change to their existing facility prior to November 16,
2007, the percent Y is determined from the following equation: Y = 1.0
- 0.575 log X, where the value of ``X'' is 1982 minus the year of
construction, and for owners or operators that made a physical or
operational change to their existing facility on or after November 16,
2007, the percent Y is determined from the following equation: Y = 1.0
- 0.575 log X, where the value of ``X'' is 2006 minus the year of
construction. Section IV.E.3 of this preamble provides a summary of key
comments we received on the NSPS subparts VV and VVa reconsideration
issues and our responses.
F. What other changes have been made to the NESHAP and NSPS?
This rule also finalizes, as proposed, revisions to several other
NESHAP and NSPS requirements. We describe these revisions in this
section as well as other proposed provisions that have changed since
proposal.
To increase the ease and efficiency of data submittal and data
accessibility, we are finalizing, as proposed, a requirement that
owners or operators submit electronic copies of certain required
performance test reports, flare management plans, and periodic reports
(including fenceline monitoring reports for HON and the P&R I NESHAP)
through the EPA's Central Data Exchange (CDX) using the Compliance and
Emissions Data Reporting Interface (CEDRI) (see 40 CFR 63.108(e), 40
CFR 63.152(c) and (h), and 40 CFR 63.182(d) and (e) (for HON), 40 CFR
63.506(e)(6), and (i)(3) (for the P&R I NESHAP), and 40 CFR 63.528(a)
and (d) (for the P&R II NESHAP), 40 CFR 60.486(l), and 60.487(a) and
(g) through (i) (for NSPS subpart VV), 40 CFR 60.486a(l), and
60.487a(a) and (g) through (i) (for NSPS subpart VVa), 40 CFR
60.486b(l), and 60.487b(a) and (g) through (i) (for NSPS subpart VVb),
40 CFR 60.615(b), (j), (k), and (m) through (o) (for NSPS subpart III),
40 CFR 60.615a(b), (h) through (l), and (n), and 40 CFR 619a(e) (for
NSPS subpart IIIa), 40 CFR 60.665(b), (l), (m), and (q) through (s)
(for NSPS subpart NNN), 40 CFR 60.665a(b), (h), (k) through (n), and
(p), and 40 CFR 669a(e) (for NSPS subpart NNNa), 40 CFR 60.705(b), (l),
(m), and (u) through (w) (for NSPS subpart RRR), and 40 CFR 60.705a(b),
(k) through (o), and (v), and 40 CFR 709a(e) (for NSPS subpart RRRa)).
A description of the electronic data submission process is provided in
the memorandum, Electronic Reporting Requirements for New Source
Performance Standards (NSPS) and National Emission Standards for
Hazardous Air Pollutants (NESHAP) Rules (see Docket Item No. EPA-HQ-
OAR-2022-0730-0002). The final rule requires that performance test
results collected using test methods that are supported by the EPA's
Electronic Reporting Tool (ERT) as listed on the ERT website \30\ at
the time of the test be submitted in the format generated through the
use of the ERT or an electronic file consistent with the xml schema on
the ERT website, and other performance test results be submitted in
portable document format (PDF) using the attachment module of the ERT.
For periodic reports (including fenceline monitoring reports), the
final rule requires that owners or operators use the appropriate
spreadsheet template to submit information to CEDRI. We have made minor
clarifying edits to the spreadsheet templates based on comments
received during the public comment period. The final version of the
templates for these reports are located on the CEDRI website.\31\ The
final rule requires that flare management plans be submitted as a PDF
upload in CEDRI. Furthermore, we are finalizing, as proposed,
provisions in the NSPS that allow facility operators the ability to
seek extensions for submitting electronic reports for circumstances
beyond the control of the facility, i.e., for a possible outage in the
CDX or CEDRI or for a force majeure event in the time just prior to a
report's due date, as well as the process to assert such a claim. For a
more detailed discussion of these final amendments, see section III.E.3
of the proposal preamble (see 88 FR 25080, April 25, 2023), as well as
sections IV.F and VI.B of this preamble.
---------------------------------------------------------------------------
\30\ <a href="https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert">https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert</a>.
\31\ <a href="https://www.epa.gov/electronic-reporting-air-emissions/cedri">https://www.epa.gov/electronic-reporting-air-emissions/cedri</a>.
---------------------------------------------------------------------------
Also, we are finalizing, as proposed, the restructuring of all HON
definitions from NESHAP subparts G and H (i.e., 40 CFR 63.111 and 40
CFR 63.161, respectively) into the definition section of NESHAP subpart
F (i.e., 40 CFR 63.101). To consolidate differences between certain
definitions in these subparts, we are also finalizing the amendments we
proposed in Table 30 of the proposal preamble (88 FR 25080, April 25,
2023), with only minor changes based on comments received on the
proposed rulemaking. The comments and our specific responses to these
items can be found in the document titled Summary of Public Comments
and Responses for New Source Performance Standards for the Synthetic
Organic Chemical Manufacturing Industry and National Emission Standards
for Hazardous Air Pollutants for the Synthetic Organic Chemical
Manufacturing Industry and Group I & II Polymers and Resins Industry,
which is available in the docket for this rulemaking.
In addition, we are finalizing requirements, as proposed, at 40 CFR
63.114(a)(5)(v), 40 CFR 63.120(d)(1)(iii), 40 CFR 63.127(b)(4), and 40
CFR
[[Page 42953]]
63.139(d)(5) (for HON), and 40 CFR 63.484(t), 40 CFR 63.485(x), and 40
CFR 63.489(b)(10) (for the P&R I NESHAP) for owners or operators using
adsorbers that cannot be regenerated and regenerative adsorbers that
are regenerated offsite to use dual (two or more) adsorbent beds in
series and conduct monitoring of HAP or TOC on the outlet of the first
adsorber bed in series using a sample port and a portable analyzer or
chromatographic analysis. However, we have clarified in the proposed
rule text in this final action that the monitoring plan provisions in
40 CFR 63.120(d)(2) and (3) do not apply to HON sources subject to the
monitoring provisions in 40 CFR 63.120(d)(1)(iii); and the monitoring
plan provisions in 40 CFR 63.120(d)(2) and (3) do not apply to P&R I
sources subject to the monitoring provisions in 40 CFR
63.120(d)(1)(iii) (via 40 CFR 63.484(t) and 40 CFR 63.485(x)). The
comments and our specific responses to these items can be found in the
document titled Summary of Public Comments and Responses for New Source
Performance Standards for the Synthetic Organic Chemical Manufacturing
Industry and National Emission Standards for Hazardous Air Pollutants
for the Synthetic Organic Chemical Manufacturing Industry and Group I &
II Polymers and Resins Industry, which is available in the docket for
this rulemaking.
We are also finalizing, as proposed, several corrections to the
calibration drift assessment requirements in NSPS subpart VVa at 40 CFR
60.485a(b)(2). These amendments include: (1) Correcting a regulatory
citation to read ``Sec. 60.486a(e)(8)'' instead of ``Sec.
60.486a(e)(7)''; (2) removing the extraneous sentence ``Calculate the
average algebraic difference between the three meter readings and the
most recent readings and the most recent calibration value.''; (3)
providing clarity in the mathematical step of the assessment by
replacing the sentence ``Divide this algebraic difference by the
initial calibration value and multiply by 100 to express the
calibration drift as a percentage.'' with ``Divide the arithmetic
difference of the initial and post-test calibration response by the
corresponding calibration gas value for each scale and multiply by 100
to express the calibration drift as a percentage.''; and (4) providing
clarity by making other minor textural changes to the provisions
related to the procedures for when a calibration drift assessment shows
negative or positive drift of more than 10 percent. We did not receive
any comments in opposition of these amendments.
In addition, we are finalizing, as proposed, the requirement in the
HON and the P&R I and P&R II NESHAP, and NSPS subparts IIIa, NNNa, and
RRRa to conduct subsequent performance testing on non-flare control
devices no later than 60 calendar months after the previous performance
test. The comments and our specific response to this item can be found
in the document titled Summary of Public Comments and Responses for New
Source Performance Standards for the Synthetic Organic Chemical
Manufacturing Industry and National Emission Standards for Hazardous
Air Pollutants for the Synthetic Organic Chemical Manufacturing
Industry and Group I & II Polymers and Resins Industry, which is
available in the docket for this rulemaking.
Also, we are finalizing, as proposed to: (1) Remove the provisions
that allow compliance with certain portions of 40 CFR part 264, subpart
AA or CC in lieu of portions of NESHAP subpart G (see 40 CFR
63.110(h)); and (2) remove the provisions that allow compliance with
certain portions of 40 CFR part 65 in lieu of portions of NESHAP
subparts G and H (see 40 CFR 63.110(i) and 40 CFR 60.160(g)). In
addition, based on comments received on the proposed rulemaking, we
are: (1) Revising 40 CFR 63.160(b)(1) and (c)(1) in the final rule such
that compliance with HON subpart H constitutes compliance with NSPS
subpart VVa provided the owner or operator continues to comply with 40
CFR 60.480a(e)(2)(i); and (2) revising 40 CFR 63.160(b)(1) and (c)(1)
in the final rule such that compliance with HON subpart H constitutes
compliance with NSPS subpart VVb provided the owner or operator
continues to comply with 40 CFR 60.480b(e)(2)(i). We have also revised
40 CFR 60.480b(e)(2)(i) in the final rule to require compliance with 40
CFR 60.482-7b (i.e., the standards for gas and light liquid valves in
NSPS subpart VVb) in addition to the requirements of 40 CFR 60.485b(d),
(e), and (f), and 40 CFR 60.486b(i) and (j). The comments and our
specific responses to these items can be found in the document titled
Summary of Public Comments and Responses for New Source Performance
Standards for the Synthetic Organic Chemical Manufacturing Industry and
National Emission Standards for Hazardous Air Pollutants for the
Synthetic Organic Chemical Manufacturing Industry and Group I & II
Polymers and Resins Industry, which is available in the docket for this
rulemaking.
Finally, we are finalizing all of the revisions that we proposed
for clarifying text or correcting typographical errors, grammatical
errors, and cross-reference errors. These editorial corrections and
clarifications are discussed in section III.E.5.f of the proposal
preamble (see 88 FR 25080, April 25, 2023). We are also including
several additional minor clarifying edits in the final rule based on
comments received during the public comment period. The comments and
our specific responses to these items can be found in the document
titled Summary of Public Comments and Responses for New Source
Performance Standards for the Synthetic Organic Chemical Manufacturing
Industry and National Emission Standards for Hazardous Air Pollutants
for the Synthetic Organic Chemical Manufacturing Industry and Group I &
II Polymers and Resins Industry, which is available in the docket for
this rulemaking.
G. What are the effective and compliance dates of the standards?
1. HON and the P&R I and P&R II NESHAP
For all of the requirements we are finalizing under CAA sections
112(d)(2), (3), and (6), and 112(h) (except for the removal of
affirmative defense provisions in the P&R I NESHAP and fenceline
monitoring requirements in HON and the P&R I NESHAP), all existing
affected sources and all affected sources that were new sources under
the previous HON and P&R I NESHAP (i.e., sources that commenced
construction or reconstruction after December 31, 1992 (for HON) or
after June 12, 1995 (for the P&R I NESHAP), and on or before April 25,
2023), must comply with all of the amendments no later than July 15,
2027, or upon startup, whichever is later. For existing sources, CAA
section 112(i) provides that the compliance date for standards
promulgated under section 112(d) shall be as expeditious as
practicable, but no later than 3 years after the effective date of the
standard. Association of Battery Recyclers v. EPA, 716 F.3d 667, 672
(D.C. Cir. 2013) (``Section 112(i)(3)'s three-year maximum compliance
period applies generally to any emission standard . . . promulgated
under [section 112].''). We agree with the commenters (see section 11.1
of the document titled Summary of Public Comments and Responses for New
Source Performance Standards for the Synthetic Organic Chemical
Manufacturing Industry and National Emission Standards for Hazardous
Air Pollutants for the Synthetic Organic Chemical Manufacturing
Industry and
[[Page 42954]]
Group I & II Polymers and Resins Industry, which is available in the
docket for this rulemaking) that 3 years is needed for owners and
operators to implement the requirements we are finalizing under CAA
sections 112(d)(2), (3), and (6). For example, for process vents, if an
affected source has uncontrolled process vents that emit greater than
or equal to 1.0 lb/hr of total organic HAP, then a new control system,
such as a thermal oxidizer with piping, ductwork, etc., may need to be
installed (due to the removal of the TRE concept in its entirety in the
final rule). Also, additional permits (e.g., New Source Review and/or a
Title V permit modifications) may be required for new emission control
equipment. Moreover, 3 years is needed to understand the final rule
changes; revise site guidance and compliance programs; ensure
operations can meet the standards during startup and shutdown; update
operation, maintenance, and monitoring plans; upgrade emission capture
and control systems; install new flare monitoring equipment; and
install new process control systems. As provided in CAA section 112(i)
and 5 U.S.C. 801(3), all new affected sources that commenced
construction or reconstruction after April 25, 2023, are required to
comply with all requirements under CAA sections 112(d)(2), (3), (6),
and 112(h) (including fenceline monitoring) by July 15, 2024 or upon
startup, whichever is later. We are also finalizing, as proposed, that
owners or operators of P&R I affected sources must comply with the
removal of the affirmative defense provisions 60 days after the
publication date of the final rule (or upon startup, whichever is
later). We provided additional rationale for these compliance dates in
the preamble to the proposed rule (88 FR 25080, April 25, 2023).
In a change from the proposed rule, we have extended the compliance
date for fenceline monitoring (with the exception of fenceline
monitoring of chloroprene at P&R I affected sources producing neoprene,
which is discussed later in this section) from 1 to 2 years. Owners and
operators of all existing sources, and all affected sources that were
new under the current rules--i.e., sources that commenced construction
or reconstruction after December 31, 1992 (for HON) or after June 12,
1995 (for the P&R I NESHAP), and on or before April 25, 2023--must
begin fenceline monitoring 2 years after the effective date of the
final rule and, starting 3 years after the effective date of the final
rule, must perform root cause analysis and apply corrective action
requirements upon exceedance of an annual average concentration action
level. We extended the timeline for fenceline monitoring from 1 to 2
years based on comments received, which indicated that EPA Method 327
will require laboratories to increase their capacity to meet the
requirements for fenceline monitoring. We consider this expanded
timeline to be necessary to allow commercial labs to conduct the needed
method development, expand capacity, and develop the logistics needed
to meet the requirements in the final rule. We also agree with
commenters' other assertions that more time is needed to read and
assess the new fenceline monitoring requirements; prepare sampling and
analysis plans; develop and submit site-specific monitoring plans;
identify representative, accessible, and secure monitoring locations
for offsite monitors and obtain permission from the property owner to
both place and routinely access the monitors; make any necessary
physical improvements to fencelines to be able to site monitors,
including construction of access roads, physical fencing, and potential
drainage improvements; and obtain approval of any necessary capital
expenditures. We consider 2 years to be necessary to allow for all of
these things. For additional details, see section 11.1 of the document
titled Summary of Public Comments and Responses for New Source
Performance Standards for the Synthetic Organic Chemical Manufacturing
Industry and National Emission Standards for Hazardous Air Pollutants
for the Synthetic Organic Chemical Manufacturing Industry and Group I &
II Polymers and Resins Industry, which is available in the docket for
this rulemaking.
For all of the requirements we are finalizing under CAA sections
112(f) for the HON, we are finalizing as proposed, except we are
clarifying that the compliance dates we proposed are from the effective
date of the rule rather than the publication date of the proposal. In
other words, all existing affected sources and all affected sources
that were new sources under the previous HON (i.e., sources that
commenced construction or reconstruction after December 31, 1992, and
on or before April 25, 2023) must comply with the EtO requirements no
later than July 15, 2026, or upon startup, whichever is later. As
explained in the April 25, 2023, proposed rule (88 FR 25080, 25176),
CAA section 112(f)(4) prescribes the compliance date for emission
standards issued under CAA section 112(f). Ass'n of Battery Recyclers
v. EPA, 716 F.3d 667, 672 (D.C. Cir. 2013) (``[S]ection 112(f)(4)'s
two-year maximum applies more specifically to standards `under this
subsection,' i.e., section 112(f).''). For existing sources, the
earliest compliance date for CAA section 112(f) standards is 90 days.
However, the compliance period can be extended up to 2 years if the EPA
finds that more time is needed for the installation of controls. 42
U.S.C. 7412(f)(4)(B). The EPA finds that the new EtO provisions under
CAA section 112(f) will require additional time to plan, purchase, and
install emission control equipment. For example, for process vents, if
an affected source cannot demonstrate 99.9-percent control of EtO
emissions, or reduce EtO emissions to less than 1 ppmv (from each
process vent) or 5 pounds per year (for all combined process vents),
then a new control system, such as a scrubber with piping, ductwork,
feed tanks, etc., may need to be installed. Similarly, this same
scenario (i.e., installation of a new control system, such as a
scrubber with piping, ductwork, feed tanks, etc) may be necessary for
storage vessels in order to reduce EtO emissions by greater than or
equal to 99.9 percent by weight or to a concentration less than 1 ppmv.
Likewise, a new steam stripper may be needed control wastewater with a
total annual average concentration of EtO greater than or equal to 1
ppmw. Additionally, we agree with commenters (see section 11.1 of the
document titled Summary of Public Comments and Responses for New Source
Performance Standards for the Synthetic Organic Chemical Manufacturing
Industry and National Emission Standards for Hazardous Air Pollutants
for the Synthetic Organic Chemical Manufacturing Industry and Group I &
II Polymers and Resins Industry, which is available in the docket for
this rulemaking) that additional permits may be required for these new
emission control equipment (e.g., New Source Review and/or a Title V
permit modifications). In other words, sufficient time is needed to
properly engineer the project, obtain capital authorization and
funding, procure the equipment, obtain permits, and construct and
start-up the equipment. Therefore, we are finalizing a compliance date
of 2 years after the effective date of the final rule for all existing
affected sources to meet the EtO requirements. All new affected sources
that commence construction or reconstruction after April 25, 2023, are
required to comply with the EtO requirements for the HON by July 15,
2024 or upon startup, whichever is later.
[[Page 42955]]
This compliance schedule is consistent with the compliance deadlines
outlined in the CAA under section 112(f)(4) and the CRA. We provided
additional rationale for these compliance dates in the preamble to the
proposed rule (88 FR 25080, April 25, 2023).
In a change from the proposed rule, the EPA is shortening the
compliance deadline for affected sources producing neoprene, due to the
EPA's finding that chloroprene emissions from the only such source pose
an imminent and substantial endangerment under CAA section 303, 42
U.S.C. 7603. United States v. Denka Performance Elastomer, LLC, et al.,
No. 2:23-cv-00735 (E.D. La. filed Feb. 28, 2023). All existing affected
sources producing neoprene and all affected sources producing neoprene
that were new sources under the previous P&R I NESHAP (i.e., sources
that commenced construction or reconstruction after June 12, 1995, and
on or before April 25, 2023) must comply with the chloroprene
requirements we are finalizing under CAA section 112(f) for the P&R I
NESHAP (see sections III.B.1 and IV.A.3.e of this preamble for a
details about these chloroprene requirements) no later than October 15,
2024,\32\ or upon startup, whichever is later. However, such sources
may seek the EPA's approval of a waiver from the 90-day compliance
deadline and obtain a compliance date of up to July 15, 2026 if they
demonstrate to the Administrator's satisfaction that ``such period is
necessary for the installation of controls'' and that steps will be
taken during the waiver period to assure that the public health of
persons will be protected from any imminent endangerment. See 42 U.S.C.
112(f)(4)(B); 40 CFR 63.6(i)(4)(ii).\33\
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\32\ The compliance date is 90 days after the effective date of
this final action due to the Congressional Review Act.
\33\ We are revising the General Provisions table to the P&R II
NESHAP entry for 40 CFR 63.6(e)(1)(i) by changing the ``No'' to
``Yes'' for affected sources producing neoprene. EPA is also
retaining authority to grant or deny requests for extensions of the
compliance date under 40 CFR 63.6(i)(4)(ii) at 40 CFR 63.507(c)(6),
and is not delegating that authority to states.
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All new affected sources that commence construction or
reconstruction after April 25, 2023, are required to comply with the
chloroprene requirements for P&R I affected sources producing neoprene
no later than by July 15, 2024 or upon startup, whichever is later.
This compliance schedule is consistent with the compliance deadlines
outlined in the CAA under section 112(f)(4) and the CRA, 5 U.S.C. 801.
2. NSPS Subparts VV, VVa, VVb, III, IIIa, NNN, NNNa, RRR, RRRa
All sources of equipment leaks in the SOCMI (regulated under NSPS
subpart VVb) and all SOCMI air oxidation unit processes, distillation
operations, and reactor processes (regulated under NSPS subparts IIIa,
NNNa, and RRRa, respectively), that commenced construction,
reconstruction, or modification on or after April 25, 2023, must meet
the requirements of the new NSPS upon startup of the new, reconstructed
or modified facility or by July 15, 2024, whichever is later. This
compliance schedule is consistent with the requirements in section 111
of the CAA and the CRA.
Also, for NSPS subparts VV, VVa, III, NNN, and RRR, we are
finalizing, as proposed, the change in format of the reporting
requirements to require electronic reporting (i.e., we are not
finalizing any new data elements); and owners and operators must begin
submitting performance test reports electronically beginning on July
15, 2024 and semiannual reports on and after July 15, 2025 or once the
report template for the subpart has been available on the CEDRI website
(<a href="https://www.epa.gov/electronic-reporting-air-emissions/cedri">https://www.epa.gov/electronic-reporting-air-emissions/cedri</a>) for 1
year, whichever date is later. For NSPS subparts IIIa, NNNa, and RRRa,
we are finalizing, as proposed, that owners and operators must submit
performance test reports electronically within 60 days after the date
of completing each performance test, and for NSPS subparts VVb, IIIa,
NNNa, and RRRa, semiannual reports on and after July 15, 2024 or once
the report template for the subpart has been available on the CEDRI
website (<a href="https://www.epa.gov/electronic-reporting-air-emissions/cedri">https://www.epa.gov/electronic-reporting-air-emissions/cedri</a>)
for 1 year, whichever date is later.
IV. What is the rationale for our final decisions and amendments for
the SOCMI, P&R I, and P&R II source categories?
For each issue, this section provides a description of what we
proposed and what we are finalizing for the issue, the EPA's rationale
for the final decisions and amendments, and a summary of key comments
and responses. For all comments not discussed in this preamble, comment
summaries and the EPA's responses can be found in the document titled
Summary of Public Comments and Responses for New Source Performance
Standards for the Synthetic Organic Chemical Manufacturing Industry and
National Emission Standards for Hazardous Air Pollutants for the
Synthetic Organic Chemical Manufacturing Industry and Group I & II
Polymers and Resins Industry, which is available in the docket for this
rulemaking.
A. Residual Risk Review for the SOCMI and Neoprene Production Source
Categories NESHAP
1. What did we propose pursuant to CAA section 112(f) for the SOCMI and
Neoprene Production source categories?
a. SOCMI Source Category
Pursuant to CAA section 112(f), the EPA conducted a residual risk
review and presented the results of this review, along with our
proposed decisions regarding risk acceptability and ample margin of
safety, in the April 25, 2023, proposed rule for the SOCMI source
category subject to HON (88 FR 25080). The results of the risk
assessment for the proposal are presented briefly in Table 1 of this
preamble. More detail is in the residual risk technical support
document, Residual Risk Assessment for the SOCMI Source Category in
Support of the 2023 Risk and Technology Review Proposed Rule (see
Docket Item No. EPA-HQ-OAR-2022-0730-0085).
[[Page 42956]]
[GRAPHIC] [TIFF OMITTED] TR16MY24.004
The results of the proposed chronic baseline inhalation cancer risk
assessment at proposal indicated that, based on estimates of current
actual and allowable emissions, the maximum individual lifetime cancer
risk posed by the source category was 2,000-in-1 million driven by EtO
emissions from PRDs (74 percent) and equipment leaks (20 percent). At
proposal, the total estimated cancer incidence from this source
category was estimated to be 2 excess cancer cases per year.
Approximately 7.2 million people were estimated to have cancer risks
above 1-in-1 million from HAP emitted from the facilities in this
source category. At proposal, the estimated maximum chronic noncancer
target organ-specific hazard index (TOSHI) for the source category was
2 for respiratory effects at two different facilities (from maleic
anhydride emissions at one facility and chlorine emissions at another
facility).
As shown in Table 1 of this preamble, the worst-case acute hazard
quotient (HQ) (based on the reference exposure level (REL)) at proposal
was 3 based on the RELs for chlorine and acrolein. In addition, at
proposal, the multipathway risk screening assessment resulted in a
maximum Tier 3 cancer screening value (SV) of 60 for mercury and 2 for
cadmium for the fisher scenario, and 20 for polycyclic organic matter
(POM) for the gardener scenario. At proposal, no site-specific
assessment using TRIM.FaTE (which incorporates AERMOD deposition,
enhanced soil/water run-off calculations, and model boundary
identification) was deemed necessary. The EPA determined that it is not
necessary to go beyond the Tier 3 lake analysis or conduct a site-
specific assessment for cadmium, mercury, or POM. The EPA compared the
Tier 3 screening results to site-specific risk estimates for five
previously assessed source categories and concluded that if the Agency
was to perform a site-specific assessment for the SOCMI source
category, the HQ for ingestion exposure, specifically cadmium and
mercury through fish ingestion, is at or below 1; and for POM, the
maximum cancer risk under the rural gardener scenario would likely
decrease to below 1-in-1 million. Also, at proposal, the highest annual
average lead concentration of 0.004 micrograms per cubic meter ([mu]g/
m\3\) was well below the National Ambient Air Quality Standards (NAAQS)
for lead, indicating low potential for multipathway risk of concern due
to lead emissions.
At proposal, the maximum lifetime individual cancer risk posed by
the 195 modeled facilities, based on whole-facility emissions, was
2,000-in-1 million, with EtO emissions from PRDs (74 percent) and
equipment leaks (20 percent) from SOCMI source category emissions
driving the risk. Regarding the noncancer risk assessment, the maximum
chronic noncancer hazard index (HI) posed by whole-facility emissions
was estimated to be 4 (for respiratory effects) due mostly (98 percent)
to emissions from 2 facilities.
We weighed all health risk measures and factors, including those
shown in Table 1 of this preamble, in our risk acceptability
determination and proposed that the risks posed by the SOCMI source
category under the current MACT provisions are unacceptable (section
III.B of the proposal preamble, 88 FR 25080, April 25, 2023). At
proposal, we identified EtO as the driver of the unacceptable risk and
evaluated several options to control EtO emissions from (1) process
vents, (2) storage vessels, (3) equipment leaks, (4) heat exchange
systems, and (5) wastewater ``in ethylene oxide service.''
[[Page 42957]]
We also proposed requirements to reduce EtO emissions from maintenance
vents, flares, and PRDs.
For process vents, we proposed to define ``in ethylene oxide
service'' in the HON at 40 CFR 63.101 to mean each process vent in a
process that, when uncontrolled, contains a concentration of greater
than or equal to 1 ppmv undiluted EtO, and when combined, the sum of
all these process vents would emit uncontrolled EtO emissions greater
than or equal to 5 pounds per year (2.27 kilograms per year).
For storage vessels of any capacity and vapor pressure, we proposed
to define ``in ethylene oxide service'' in the HON at 40 CFR 63.101 to
mean that the concentration of EtO of the stored liquid is at least 0.1
percent by weight. Additionally, we proposed that unless specified by
the Administrator, owners and operators may calculate the concentration
of EtO of the fluid stored in a storage vessel if information specific
to the fluid stored is available such as concentration data from safety
data sheets. We also proposed that the exemption for ``vessels storing
organic liquids that contain organic hazardous air pollutants only as
impurities'' listed in the definition of ``storage vessel'' at 40 CFR
63.101 does not apply for storage vessels in EtO service.
For the EtO equipment leak provisions, we proposed to define ``in
ethylene oxide service'' in the HON at 40 CFR 63.101 to mean any
equipment that contains or contacts a fluid (liquid or gas) that is at
least 0.1 percent by weight of EtO.
For heat exchange systems, we proposed to define ``in ethylene
oxide service'' in the HON at 40 CFR 63.101 to mean each heat exchange
system in a process that cools process fluids (liquid or gas) that are
0.1 percent or greater by weight of EtO.
For wastewater, we proposed to define ``in ethylene oxide service''
in the HON at 40 CFR 63.101 to mean each wastewater stream that
contains total annual average concentration of EtO greater than or
equal to 1 ppmw at any flow rate.
To reduce risks from process vents in EtO service, we proposed
requirements at 40 CFR 63.113(j) to reduce emissions of EtO by either
(1) venting emissions through a closed-vent system to a control device
that reduces EtO by greater than or equal to 99.9 percent by weight, to
a concentration less than 1 ppmv for each process vent, or to less than
5 lb/yr for all combined process vents; or (2) venting emissions
through a closed-vent system to a flare meeting the flare operating
requirements discussed in section III.B.4.a.i of the proposal preamble
(88 FR 25080, April 25, 2023).
To reduce risks from storage vessels in EtO service, we proposed a
requirement at 40 CFR 63.119(a)(5) to reduce emissions of EtO by either
(1) venting emissions through a closed-vent system to a control device
that reduces EtO by greater than or equal to 99.9 percent by weight or
to a concentration less than 1 ppmv for each storage vessel vent; or
(2) venting emissions through a closed-vent system to a flare meeting
the flare operating requirements discussed in section IV.A.1 of the
proposal preamble (84 FR 69182, December 17, 2019).
To reduce risks from equipment leaks in EtO service, we proposed
the following combined requirements: monitoring of connectors in gas/
vapor and light liquid service at a leak definition of 100 ppm on a
monthly basis with no reduction in monitoring frequency or delay of
repair (at 40 CFR 63.174(a)(3) and 40 CFR 63.174(b)(3)(vi)); light
liquid pump monitoring at a leak definition of 500 ppm monthly (at 40
CFR 63.163(b)(2)(iv)); and gas/vapor and light liquid valve monitoring
at a leak definition of 100 ppm monthly with no reduction in monitoring
frequency or delay of repair (at 40 CFR 63.168(b)(2)(iv) and 40 CFR
63.168(d)(5)).
To reduce risks from EtO emissions due to heat exchange system
leaks, we proposed at 40 CFR 63.104(g)(6) to require weekly monitoring
for leaks for heat exchange systems in EtO service using the Modified
El Paso Method, and if a leak is found, we proposed at 40 CFR
63.104(h)(6) that owners and operators must repair the leak to reduce
the concentration or mass emissions rate to below the applicable leak
action level as soon as practicable, but no later than 15 days after
the sample was collected with no delay of repair allowed.
To reduce risks from wastewater in EtO service, we proposed at 40
CFR 63.132(c)(1)(iii) and (d)(1)(ii) that owners and operators of HON
sources manage and treat any wastewater streams that are ``in ethylene
oxide service.'' We also proposed at 40 CFR 63.104(k) to prohibit
owners and operators from injecting water into or disposing of water
through any heat exchange system in a CMPU meeting the conditions of 40
CFR 63.100(b)(1) through (3) if the water contains any amount of EtO,
has been in contact with any process stream containing EtO, or the
water is considered wastewater as defined in 40 CFR 63.101.
In addition, we proposed at 40 CFR 63.165(e)(3)(v)(D) that any
release event from a PRD in EtO service is a violation of the standard
to ensure that these process vent emissions are controlled and do not
bypass controls. Also, in order to help reduce EtO risk from the SOCMI
source category to an acceptable level, we proposed: (1) A requirement
at 40 CFR 63.113(k)(4) that owners and operators cannot release more
than 1.0 ton of EtO from all maintenance vents combined in any
consecutive 12-month period; and (2) a requirement at 40 CFR 63.108(p)
that owners and operators can send no more than 20 tons of EtO to all
of their flares combined in any consecutive 12-month period from all
HON emission sources at a facility.
After implementation of the proposed controls for: (1) Process
vents, (2) storage vessels, (3) equipment leaks, (4) heat exchange
systems, and (5) wastewater ``in ethylene oxide service,'' as well as
implementation of the proposed requirements to reduce EtO emissions
from maintenance vents, flares, and PRDs, we proposed that the
resulting risks would be acceptable for the SOCMI source category. We
determined at proposal that estimated post-control risks would be
reduced to 100-in-1 million (down from 2,000-in-1 million) with no
individuals exposed to risk levels greater than 100-in-1 million from
HAP emissions from HON processes (see section III.B.2 of the proposal
preamble, 88 FR 25080, April 25, 2023).
We then considered whether the existing MACT standards provide an
ample margin of safety to protect public health and whether, taking
into consideration costs, energy, safety, and other relevant factors,
additional standards are required to prevent an adverse environmental
effect. We noted that the EPA previously made a determination that the
standards for the SOCMI source category provided an ample margin of
safety to protect public health, and that the most significant change
since that determination was the revised 2016 IRIS inhalation URE for
EtO and new 2010 IRIS inhalation URE for chloroprene. As such, we
focused our ample margin of safety analysis on cancer risk for EtO and
chloroprene, since these pollutants, even after application of controls
needed to get risks to an acceptable level, drive cancer risk and
cancer incidence (i.e., 60 percent of remaining cancer incidence is
from EtO) for the SOCMI source category. The ample margin of safety
analysis for the SOCMI source category identified no other control
options for EtO beyond those proposed to reduce risks to an acceptable
level. For chloroprene emissions from HON-subject sources, we
identified control
[[Page 42958]]
options for equipment leaks and maintenance activities; however, the
options evaluated were found not to be cost-effective (see sections
III.C.6 and III.D.4 of the proposal preamble, 88 FR 25080, April 25,
2023). Therefore, we proposed that the requirements that we proposed to
achieve acceptable risk would also provide an ample margin of safety to
protect public health (section III.B.3 of the proposal preamble, 88 FR
25080, April 25, 2023).
b. Neoprene Production Source Category
Pursuant to CAA section 112(f), the EPA conducted a residual risk
review and presented the results of this review, along with our
proposed decisions regarding risk acceptability and ample margin of
safety, in the April 25, 2023, proposed rule for the Neoprene
Production source category subject to the P&R I NESHAP (88 FR 25080).
The results of the risk assessment for the proposal are presented
briefly in Table 2 of this preamble. More detail is in the residual
risk technical support document, Residual Risk Assessment for the
Polymers & Resins I Neoprene Production Source Category in Support of
the 2023 Risk and Technology Review Proposed Rule (see Docket Item No.
EPA-HQ-OAR-2022-0730-0095).
[GRAPHIC] [TIFF OMITTED] TR16MY24.005
The results of the proposed chronic baseline inhalation cancer risk
assessment at proposal indicated that, based on estimates of current
actual and allowable emissions, the MIR posed by the source category
was 500-in-1 million, driven by chloroprene emissions from maintenance
vents (67 percent), storage vessels (11 percent), wastewater (8
percent), and equipment leaks (4 percent). At proposal, the total
estimated cancer incidence from this source category was estimated to
be 0.05 excess cancer cases per year, or 1 cancer case every 20 years.
Approximately 690,000 people were estimated to have cancer risks above
1-in-1 million from HAP emitted from this source category. At proposal,
the estimated maximum chronic noncancer TOSHI for the source category
was 0.05 for respiratory effects from chloroprene emissions.
As shown in Table 2 of this preamble, the worst-case acute HQ at
proposal was 0.3 based on the REL for chloroform. In addition, at
proposal, we did not undertake the three-tier human health risk
screening ass
[…truncated; see source link]Indexed from Federal Register on May 16, 2024.
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