[Federal Register Volume 90, Number 9 (Wednesday, January 15, 2025)]
[Proposed Rules]
[Pages 3734-3752]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-31227]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 60
[EPA-HQ-OAR-2024-0358; FRL-12031-01-OAR]
RIN 2060-AW35
Reconsideration of Standards of Performance for New,
Reconstructed, and Modified Sources and Emissions Guidelines for
Existing Sources: Oil and Natural Gas Sector Climate Review
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing
amendments to the New Source Performance Standards and Emission
Guidelines for Existing Sources for the Crude Oil and Natural Gas
Source Category in response to petitions for reconsideration.
Specifically, this action proposes discrete technical changes to two
different aspects of the rules. First, this action proposes discrete
technical changes to the temporary flaring provisions for associated
gas in certain situations. Second, this action proposes discrete
technical changes to the vent gas net heating value (NHV) continuous
monitoring requirements and alternative performance test (sampling
demonstration) option for flares and enclosed combustion devices. In a
letter dated May 6, 2024, the EPA notified petitioners and the public
that the Agency granted reconsideration on these two aspects of the
March 8, 2024 (89 FR 16820) final rule. These amendments neither
propose changes to any other aspect of the final rule, nor propose to
alter the substance of any emission standards within the final rule.
Also, in this action, the EPA proposes to make formatting changes to
the regulatory text to meet the required formatting standards of the
Office of the Federal Register.
DATES: Comments. Comments must be received on or before March 3, 2025.
Public Hearing. If anyone contacts us requesting a public hearing
on or before January 20, 2025, we will hold a virtual public hearing.
Please refer to the SUPPLEMENTARY INFORMATION for information on
requesting and registering for a public hearing.
ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2024-0358, by any of the following methods:
Federal eRulemaking Portal: https://www.regulations.gov
(our preferred method). Follow the online instructions for submitting
comments.
Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2024-0358 in the subject line of the message.
Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Docket ID No. EPA-HQ-OAR-2024-0358, Mail Code 28221T, 1200
Pennsylvania Avenue NW, Washington, DC 20460.
Hand/Courier Delivery: EPA Docket Center, WJC West
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004.
The Docket Center's hours of operation are 8:30 a.m.-4:30 p.m., Monday-
Friday (except Federal Holidays).
Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received may be posted without change
to https://www.regulations.gov, including any personal information
provided. For detailed instructions on sending comments and additional
information on the rulemaking process, see the SUPPLEMENTARY
INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Frank Benjamin-Eze, Sector Policies
and Programs Division (E143-05), Office of Air Quality Planning and
Standards, U.S. Environmental Protection Agency, 109 T.W. Alexander
Drive, P.O. Box 12055 RTP, North Carolina 27711; telephone number:
(919) 541-3753; and email address: [email protected].
Additional questions may be directed to the following email address:
[email protected].
SUPPLEMENTARY INFORMATION:
Participation in virtual public hearing. To request a virtual
public hearing, contact the public hearing team at (888) 372-8699 or by
email at [email protected]. If requested, the virtual public
hearing will be held via virtual platform. The EPA will announce the
date of the hearing and further details on the virtual public hearing
at https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-operations. The hearing will convene at 11:00 a.m. Eastern Time (ET)
and will conclude at 4:00 p.m. ET. The EPA may close a session 15
minutes after the last pre-registered speaker has testified if there
are not additional speakers.
The EPA will begin pre-registering speakers for the hearing no
later than 1 business day after a request has been received. To
register to speak at the virtual hearing, please use the online
registration form available at https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-operations or contact the public hearing
team at (888) 372-8699 or by email at [email protected]. The
last day to pre-register to speak at the hearing will be January 27,
2025. Prior to the hearing, the EPA will post a general agenda that
will list pre-registered speakers at: https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-operations.
The EPA will make every effort to follow the schedule as closely as
possible on the day of the hearing; however, please plan for the
hearings to run either ahead of schedule or behind schedule. Each
commenter will have 4 minutes to provide oral testimony. The EPA
encourages commenters to submit a copy of their oral testimony as
written comments to the rulemaking docket. The EPA may ask clarifying
questions during the oral presentations but will not respond to the
presentations at that time. Written statements and supporting
information submitted during the comment period will be considered with
the same weight as oral testimony and supporting information presented
at the public hearing.
Please note that any updates made to any aspect of the hearing will
be posted online at https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-operations. While the EPA expects the hearing to go
forward as set forth above, please monitor these websites or contact
the public hearing team at (888) 372-8699 or by email at
[email protected] to
[[Page 3735]]
determine if there are any updates. The EPA does not intend to publish
a document in the Federal Register announcing updates.
If you require the services of a translator or a special
accommodation such as audio description, please pre-register for the
hearing with the public hearing team and describe your needs by January
22, 2025. The EPA may not be able to arrange accommodations without
advance notice.
Docket. The EPA has established a docket for this rulemaking under
Docket ID No. EPA-HQ-OAR-2024-0358. All documents in the docket are
listed in the Regulations.gov index. Although listed in the index, 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 as pdf
versions that can only be accessed on the EPA computers in the docket
office reading room. Certain data bases and physical items cannot be
downloaded from the docket but may be requested by contacting the
docket office at (202) 566-1744. The docket office has up to 10
business days to respond to these requests. With the exception of such
material, publicly available docket materials are available
electronically in Regulations.gov.
Written Comments. Submit your comments, identified by Docket ID No.
EPA-HQ-OAR-2024-0358, at https://www.regulations.gov (our preferred
method), or the other methods identified in the ADDRESSES section. Once
submitted, comments cannot be edited or removed from the docket. The
EPA may publish any comment received to its public docket. Do not
submit to the EPA's docket at https://www.regulations.gov any
information you consider to be CBI or other information whose
disclosure is restricted by statute. This type of information should be
submitted as discussed in the Submitting CBI section of this document.
Multimedia submissions (audio, video, etc.) must be accompanied by
a written comment. The written comment is considered the official
comment and should include discussion of all points you wish to make.
The EPA will generally not consider comments or comment contents
located outside of the primary submission (i.e., on the Web, cloud, or
other file sharing system). Please visit https://www.epa.gov/dockets/commenting-epa-dockets for additional submission methods; the full EPA
public comment policy; information about CBI or multimedia submissions;
and general guidance on making effective comments.
The https://www.regulations.gov website allows you to submit your
comment anonymously, which means the EPA will not know your identity or
contact information unless you provide it in the body of your comment.
If you send an email comment directly to the EPA without going through
https://www.regulations.gov, your email address will be automatically
captured and included as part of the comment that is placed in the
public docket and made available on the internet. If you submit an
electronic comment, the EPA recommends that you include your name and
other contact information in the body of your comment and with any
digital storage media you submit. If the EPA cannot read your comment
due to technical difficulties and cannot contact you for clarification,
the EPA may not be able to consider your comment. Electronic files
should not include special characters or any form of encryption and be
free of any defects or viruses.
Submitting CBI. Do not submit information containing CBI to the EPA
through https://www.regulations.gov. Clearly mark the part or all of
the information that you claim to be CBI. For CBI information on any
digital storage media that you mail to the EPA, note the docket ID,
mark the outside of the digital storage media as CBI, and identify
electronically within the digital storage media the specific
information that is claimed as CBI. In addition to one complete version
of the comments that includes information claimed as CBI, you must
submit a copy of the comments that does not contain the information
claimed as CBI directly to the public docket through the procedures
outlined in the Written Comments section of this document. If you
submit any digital storage media that does not contain CBI, mark the
outside of the digital storage media clearly that it does not contain
CBI and note the docket ID. Information not marked as CBI will be
included in the public docket and the EPA's electronic public docket
without prior notice. Information marked as CBI will not be disclosed
except in accordance with procedures set forth in 40 Code of Federal
Regulations (CFR) part 2.
Our preferred method to receive CBI is for it to be transmitted
electronically using email attachments, File Transfer Protocol (FTP),
or other online file sharing services (e.g., Dropbox, OneDrive, Google
Drive). Electronic submissions must be transmitted directly to the
Office of Air Quality Planning and Standards (OAQPS) CBI Office at the
email address [email protected], and as described above, should include
clear CBI markings and note the docket ID. If assistance is needed with
submitting large electronic files that exceed the file size limit for
email attachments, and if you do not have your own file sharing
service, please email [email protected] to request a file transfer
link. If sending CBI information through the postal service, please
send it to the following address: OAQPS Document Control Officer (C404-
02), OAQPS, U.S. Environmental Protection Agency, 109 T.W. Alexander
Drive P.O. Box 12055 RTP, North Carolina 27711, Attention Docket ID No.
EPA-HQ-OAR-2024-0358. The mailed CBI material should be double wrapped
and clearly marked. Any CBI markings should not show through the outer
envelope.
Preamble acronyms and abbreviations. Throughout this document the
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. We
use multiple acronyms and terms in this preamble. While this list may
not be exhaustive, to ease the reading of this preamble and for
reference purposes, the EPA defines the following terms and acronyms
here:
AGR Acid gas removal
AMP Alternative Monitoring Plan
API American Petroleum Institute
ASTM American Society for Testing and Materials
BPV back pressure valve
BSER best system of emission reduction
Btu/lb British thermal units per pound
Btu/scf British thermal units per standard cubic feet
[deg]C degrees Celsius
CAA Clean Air Act
CBI Confidential Business Information
CFR Code of Federal Regulations
CO2 carbon dioxide
CRA Congressional Review Act
CVS closed vent systems
EG emission guidelines
EJ environmental justice
EOR enhanced oil recovery
EPA Environmental Protection Agency
FR Federal Register
ft3 cubic feet
GC gas chromatograph
GHG greenhouse gas
GHGRP Greenhouse Gas Reporting Program
ICR information collection request
MACT maximum achievable control technology
MS mass spectrometer
NAICS North American Industry Classification System
NHV net heating value
NHVcz combustion zone NHV
NHVdil NHV dilution parameter
NHVS net heating values
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
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O2 oxygen
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PRA Paperwork Reduction Act
RFA Regulatory Flexibility Act
RIA regulatory impact analysis
RLSO redline strike out
scf standard cubic feet
TAR Tribal Authority Rule
UMRA Unfunded Mandates Reform Act
U.S. United States
VISR Video Imaging Spectro-Radiometry
VOC volatile organic compound(s)
Organization of this document. The information in this preamble is
organized as follows:
I. General Information
A. Does this action apply to me?
B. Where can I get a copy of this document and other related
information?
II. Statutory Background and Regulatory History
A. Statutory Background of CAA Sections 111(b), 111(d), and
General Implementing Regulations
B. What is the regulatory history and background of NSPS and EG
for the Crude Oil and Natural Gas Source Category?
III. Summary and Rationale of Proposed Amendments to NSPS OOOOb and
EG OOOOc
A. Temporary Flaring Provisions for Associated Gas in Certain
Situations
B. Vent Gas Net Heating Value (NHV) Continuous Monitoring
Requirements and Alternative Performance Test (Sampling
Demonstration) Option for Flares and Enclosed Combustion Devices
IV. How do these proposed amendments impact the implementation of EG
OOOOc?
V. Summary of Cost, Environmental, and Economic Impacts
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
I. General Information
A. Does this action apply to me?
The source category that is the subject of this proposal is the
Crude Oil and Natural Gas Source Category regulated under Clean Air Act
(CAA) section 111, New Source Performance Standards (NSPS) and Emission
Guidelines (EG). The 2022 North American Industry Classification System
(NAICS) code for the source category is summarized in table 1. The
NAICS codes serve as a guide for readers outlining the entities that
this proposed action is likely to affect. The NSPS codified in 40 CFR
part 60, subpart OOOOb, are directly applicable to affected facilities
that begin construction, reconstruction, or modification after December
6, 2022. As shown in table 1, Federal, State, and local government
entities would not be affected by the NSPS action.
Table 1--Industrial Source Categories Affected by NSPS Action
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Examples of regulated
Category NAICS code entities
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Industry......................... 211120 Crude Petroleum
Extraction.
211130 Natural Gas Extraction.
221210 Natural Gas
Distribution.
486110 Pipeline Distribution of
Crude Oil.
486210 Pipeline Transportation
of Natural Gas.
Federal Government............... . . . . Not affected.
State and Local Government....... . . . . Not affected.
Tribal Government................ 921150 American Indian and
Alaska Native Tribal
Governments.
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This table is not intended to be exhaustive but rather provides a
guide for readers regarding entities likely to be affected by the NSPS
action. Other types of entities not listed in the table could also be
affected by these NSPS action. To determine whether your entity is
affected by any of the NSPS action, you should carefully examine the
applicability criteria found in the final NSPS rule. If you have
questions regarding the applicability of the NSPS rule to a particular
entity, consult the person listed in the FOR FURTHER INFORMATION
CONTACT section, your State air pollution control agency with delegated
authority for NSPS, or your EPA Regional Office.
The issuance of the CAA section 111(d) EG in March of 2024 did not
impose binding requirements directly on existing sources. The EG
codified in 40 CFR part 60, subpart OOOOc, applies to States in the
development, submittal, and implementation of State plans to establish
performance standards to reduce emissions of GHGs from designated
facilities that are existing sources on or before December 6, 2022.
Under the Tribal Authority Rule (TAR), eligible Tribes may seek
approval to implement a plan under CAA section 111(d) in a manner
similar to a State. See 40 CFR part 49, subpart A. Tribes may, but are
not required to, seek approval for treatment in a manner similar to a
State for purposes of developing a Tribal implementation plan (TIP)
implementing the EG codified in 40 CFR part 60, subpart OOOOc. The TAR
authorizes Tribes to develop and implement their own air quality
programs, or portions thereof, under the CAA. However, it does not
require Tribes to develop a CAA program. Tribes may implement programs
that are most relevant to their air quality needs. If a Tribe does not
seek and obtain the authority from the EPA to establish a TIP, the EPA
has the authority to establish a Federal CAA section 111(d) plan for
designated facilities that are located in areas of Indian country.\1\ A
Federal plan would apply to all designated facilities located in the
areas of Indian country covered by the Federal plan unless and until
the EPA approves a TIP applicable to those facilities.
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\1\ See the EPA's website, https://www.epa.gov/tribal/tribes-approved-treatment-state-tas, for information on those Tribes that
have treatment as a state for specific environmental regulatory
programs, administrative functions, and grant programs.
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B. Where can I get a copy of this document and other related
information?
In addition to being available in the docket, at Docket ID No. EPA-
HQ-OAR-2024-0358 located at https://www.regulations.gov/, an electronic
copy of this action is available on the internet at https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-operations.
In accordance with 5 U.S.C. 553(b)(4), a brief summary of this proposed
rule may be found at www.regulations.gov, Docket ID No. EPA-HQ-OAR-
2024-0358. Following publication in the Federal Register, the EPA will
post the Federal Register version of the proposal and key technical
documents at this same website.
A memorandum showing the edits that would be necessary to
incorporate the changes to 40 CFR part 60 subpart OOOOb and 40 CFR part
60 subpart OOOOc proposed in this action is available in the docket
(Docket ID No. EPA-HQ-OAR-2024-0358). Following signature by the EPA
Administrator, the EPA also will post a copy of this document to
https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-operations.
II. Statutory Background and Regulatory History
A. Statutory Background of CAA Sections 111(b), 111(d), and General
Implementing Regulations
The EPA's authority for this rulemaking is CAA section 111, 42
U.S.C. 7411,which governs the establishment of standards of performance
for stationary sources. This CAA section requires the EPA to list
source categories to be regulated, establish standards of performance
for air pollutants emitted by new sources in that source category, and
establish EG for States to establish standards of performance for
certain pollutants emitted by existing sources in that source category.
For a comprehensive discussion of the statutory background of CAA
sections 111(b), 111(d), and general implementing regulations, refer to
the discussion provided in section IV.A (Statutory Background of the
CAA sections 111(b), 111(d), and General Implementing Regulations) of
the March 2024 final rule preamble. (89 FR 16846-16848; March 8, 2024).
B. What is the regulatory history and background of NSPS and EG for the
Crude Oil and Natural Gas Source Category?
On November 15, 2021, the EPA published a proposed rule (November
2021 Proposal) to mitigate climate-destabilizing pollution and protect
human health by reducing greenhouse gas (GHG) and volatile organic
compound (VOC) emissions from the oil and natural gas industry,\2\
specifically the Crude Oil and Natural Gas source
category.3 4 In the November 2021 Proposal, the EPA proposed
new and updated standards of performance under section 111(b) of the
CAA for GHGs (in the form of methane limitations) and VOC emissions
from new, modified, and reconstructed sources in this source category,
as well as revisions to standards of performance already codified at 40
CFR part 60, subparts OOOO and OOOOa. The EPA also proposed EG under
section 111(d) of the CAA for GHGs emissions (in the form of methane
limitations) from existing sources (designated facilities).\5\ The EPA
also proposed several related actions stemming from the joint
resolution of Congress, adopted on June 30, 2021, under the
Congressional Review Act (CRA), disapproving the EPA's final rule
titled, ``Oil and Natural Gas Sector: Emission Standards for New,
Reconstructed, and Modified Sources Review,'' September 14, 2020 (2020
Policy Rule). Lastly, in the November 2021 Proposal the EPA proposed a
protocol for optical gas imaging (OGI) under the part 60 general
provisions. The only portions of the November 2021 Proposal that are
relevant to this rulemaking are specific limited provisions of the NSPS
(OOOOb) and EG (OOOOc) identified in this proposal.
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\2\ The EPA characterizes the oil and natural gas industry
operations as being generally composed of 4 segments: (1) Extraction
and production of crude oil and natural gas (``oil and natural gas
production''), (2) natural gas processing, (3) natural gas
transmission and storage, and (4) natural gas distribution.
\3\ ``Standards of Performance for New, Reconstructed, and
Modified Sources and Emissions Guidelines for Existing Sources: Oil
and Natural Gas Sector Climate Review.'' Proposed rule (86 FR 63110;
November 15, 2021).
\4\ The EPA defines the Crude Oil and Natural Gas source
category to mean: (1) Crude oil production, which includes the well
and extends to the point of custody transfer to the crude oil
transmission pipeline or any other forms of transportation; and (2)
natural gas production, processing, transmission, and storage, which
include the well and extend to, but do not include, the local
distribution company custody transfer station, commonly referred to
as the ``city-gate.''
\5\ The term ``designated facility'' means ``any existing
facility which emits a designated pollutant and which would be
subject to a standard of performance for that pollutant if the
existing facility were an affected facility.'' See 40 CFR 60.21a(b).
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On December 6, 2022, the EPA published a supplemental proposed rule
(``December 2022 Supplemental Proposal'') that was composed of two main
additions.\6\ First, the EPA proposed updated, strengthened, and
expanded NSPS OOOOb standards compared to those proposed in November
2021 under CAA section 111(b) for GHGs (in the form of methane
limitations) and VOC emissions from new, modified, and reconstructed
facilities. Second, the EPA proposed updated, strengthened, and
expanded presumptive standards compared to those proposed for EG OOOOc
in the November 2021 Proposal as part of the CAA section 111(d) EG for
GHGs emissions (in the form of methane limitations) from designated
facilities. For purposes of EG OOOOc, the EPA also proposed the
implementation requirements for State plans developed to limit GHGs
pollution (in the form of methane limitations) from designated
facilities in the Crude Oil and Natural Gas source category under CAA
section 111(d).
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\6\ ``Standards of Performance for New, Reconstructed, and
Modified Sources and Emissions Guidelines for Existing Sources: Oil
and Natural Gas Sector Climate Review.'' Supplemental notice of
proposed rulemaking (87 FR 74702; December 6, 2022).
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On March 8, 2024, at 89 FR 16820 (hereafter, referred to as the
March 2024 final rule), the EPA published the final rule with multiple
separate actions to reduce air pollution emissions from the Crude Oil
and Natural Gas source category. First, the EPA finalized NSPS OOOOb
regulating GHG (in the form of a limitation on emissions of methane)
and VOCs emissions for the Crude Oil and Natural Gas source category
pursuant to CAA section 111(b)(1)(B). Second, the EPA finalized the EG
in OOOOc to limit GHGs. Third, the EPA finalized several related
actions (including final amendments to NSPS OOOOa) stemming from the
joint resolution of Congress, adopted on June 30, 2021, under the CRA,
disapproving the 2020 Policy Rule. Fourth, the EPA finalized a protocol
under the General Provisions for optical gas imaging (OGI). The final
rule became effective 60 days after publication, which was May 7, 2024.
After the publication of the March 2024 final rule, the EPA
identified, through its own internal reassessment of the regulatory
text, as well as through communications with stakeholders and the
Office of the Federal Register, erroneous cross-references and
typographical errors within the regulatory text. Through those same
processes, the EPA also identified the need for some minor wording
changes to clarify erroneous language (or, in some cases, erroneous
omissions) in the regulatory text, and to ensure that the
[[Page 3738]]
regulatory text aligns with the descriptions of the relevant provisions
in the final rule preamble and other parts of the regulation(s). The
EPA published an interim final rule (89 FR 62872; August 1, 2024) \7\
which made minor and non-substantive corrections to the March 2024
final rule in order to correct the identified inadvertent errors.
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\7\ Docket ID No. EPA-HQ-OAR-2021-0317-4057.
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Further, after the publication of the March 2024 final rule, the
EPA received multiple petitions \8\ for reconsideration. On May 6,
2024,\9\ we notified certain petitioners and the public that we granted
reconsideration on two narrow and discrete aspects of the March 2024
final rule: (1) The temporary flaring provisions for associated gas in
certain situations; and (2) the vent gas NHV continuous monitoring
requirements and alternative performance test (sampling demonstration)
option for flares and enclosed combustion devices. These issues were
raised in petitions for reconsideration from: (1) The American
Petroleum Institute (API) and the American Exploration and Production
Council (AXPC); \10\ (2) Second petition from API/AXPC; \11\ (3) The
Texas Oil & Gas Association (TXOGA); \12\ (4) GPA Midstream Association
(GPA Midstream); and (4) Environmental Integrity Project et. al.\13\
This action proposes amendments to the March 2024 final rule as a
result of our reconsideration of these two narrow issues.\14\
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\8\ See Docket No. EPA-HQ-OAR-2024-0358 for petitions for
reconsideration received.
\9\ See Docket No. EPA-HQ-OAR-2024-0358 for May 6, 2024, letter
granting reconsideration.
\10\ Letter to Michael S. Regan, EPA Administrator, from API and
AXPC. Re: Provisions in the EPA's Final Rule ``New Source
Performance Standards and Emission Guidelines for Crude Oil and
Natural Gas Facilities: Climate Review.'' Reconsideration of the
Final Rule. May 6, 2024. Hereinafter referred to as the ``May 2024
API and AXPC petition.''
\11\ Letter to Michael S. Regan, EPA Administrator, from TXOGA.
Request for Reconsideration of the EPA's Final Rule ``New Source
Performance Standards and Emission Guidelines for Crude Oil and
Natural Gas Facilities: Climate Review.'' May 7, 2024. Hereinafter
referred to as the ``May 2024 TXOGA petition.''
\12\ Letter to Michael S. Regan, EPA Administrator; Gautam
Srinivasan, Associate General Counsel, EPA; and Amy Hambrick, SPPD,
EPA; from GPA Midstream Association. GPA Midstream Association
Petition for Reconsideration and Request for Stay of Standards of
Performance for New, Reconstructed, and Modified Sources and
Emissions Guidelines for Existing Sources: Oil and Natural Gas
Sector Climate Review. May 2, 2024. Hereinafter referred to as the
``May 2024 GPA Midstream petition.''
\13\ Letter to Michael S. Regan, EPA Administrator, from Air
Alliance Houston; Clean Air Council; and Environmental Integrity
Project. Re: Petition for Reconsideration of the Standards of
Performance for New, Reconstructed, and Modified Sources and
Emissions Guidelines for Existing Sources: Oil and Natural Gas
Sector Climate Review; Final Rule, 89 FR 16,820 (March 8, 2024),
Docket No. EPA-HQ-OAR-2021-0317. May 7, 2024. Hereinafter referred
to as the ``May 2024 EIP, et al. petition.''
\14\ In the May 6, 2024, letter to petitioners, the EPA also
took the opportunity to clarify the applicable timeframe for
performance testing with respect to NHV sampling.
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III. Summary and Rationale of Proposed Amendments to NSPS OOOOb and EG
OOOOc
The amendments proposed in this action only relate to two narrow
aspects of the March 2024 final rule: (1) The temporary flaring
provisions for associated gas in certain situations; and (2) the vent
gas NHV continuous monitoring requirements and alternative performance
test (sampling demonstration) option for flares and enclosed combustion
devices. This proposal does not address, and therefore the EPA is not
reopening, any other aspects of the March 2024 final rule aside from
these two specific aspects. Further, the two issues addressed in this
proposal are separate and distinct from each other. Each of these two
issues concern different portions of the March 2024 final rule that do
not rely on the other. Also, in this action, the EPA proposes to make
formatting changes to the regulatory text to meet the required
formatting standards of the Office of the Federal Register.\15\
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\15\ To view the proposed formatting changes, see the full
redline strike out (RLSO) of the regulatory text located in the
public docket at EPA-HQ-OAR-2024-0358.
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A. Temporary Flaring Provisions for Associated Gas in Certain
Situations
The final NSPS OOOOb requirements, and EG OOOOc presumptive
standards (model rules), allow oil wells that are not routinely flaring
associated gas (i.e., oil wells that route associated gas to sales line
or equivalent alternative), to route associated gas to a flare or
control device temporarily in certain situations. During situations
where a malfunction or incident endangers the safety of operator
personnel or the public, and during repair, maintenance including blow
downs, a production test, or commissioning, owners and operators are
allowed to route to a flare or control device for 24 hours or less per
incident. Petitions for reconsideration include information that
suggest that 24 hours for temporary flaring may not be sufficient time
in these situations to troubleshoot and repair equipment. A summary of
the relevant promulgated provisions being reconsidered is presented in
section III.A.1, and specific concerns and supporting information
provided by petitioners and other industry representatives are
presented in section III.A.2 of this preamble. After consideration of
the petitioners' concerns and supporting information, the EPA is
proposing certain discrete changes to these particular requirements
finalized in the March 2024 final rule. The proposed changes are
presented in section III.A.3 of this preamble and the EPA's rationale
for those proposed changes is presented in section III.A.4 of this
preamble.
1. Summary of Promulgated Provisions Being Reconsidered
When developing the March 2024 final rule requirements for
associated gas, the EPA recognized that temporary situations may occur
beyond the reasonable control of an owner or operator that could make
it technically infeasible or unsafe to comply with the standard that
requires the associated gas be recovered and either routed into a gas
gathering flow line or collection system to a sales line, used as an
onsite fuel source, used for another useful purpose that a purchased
fuel or raw material would serve, or reinjected into the well or inject
the recovered gas into another well. Therefore, for all associated gas
wells subject to NSPS OOOOb and complying with one of these four
options, the final rule allows owners and operators to route the
associated gas to a flare or control device temporarily. 40 CFR
60.5377b(d). The EG also includes similar provisions as part of the
model rule at 40 CFR 60.5391c(c). The NSPS OOOOb final rule allow
temporary flaring for the following situations:
(1) During a malfunction or incident that endangers the safety of
operator personnel or the public, an owner or operator is allowed to
route to a flare or control device for 24 hours or less per incident.
(2) During repair, maintenance including blow downs, a production
test, or commissioning, an owner or operator is allowed to route to a
flare or control device for 24 hours or less per incident.
(3) During a temporary interruption in service from the gathering
or pipeline system, an owner or operator is allowed to route to a flare
or route to a control device for the duration of the temporary
interruption not to exceed 30 days per incident.
(4) During periods when the composition of the associated gas does
not meet pipeline specifications for sources, or when the composition
of the associated gas does not meet the quality requirements for use as
a fuel for sources, or when the composition of the associated gas does
not meet the quality requirements for another useful purpose, an owner
or operator is
[[Page 3739]]
allowed to route to a flare or control device until the associated gas
meets the required specifications or for 72 hours per incident,
whichever is less.
This proposed rule only concerns the first two situations listed
above: (1) Malfunction/safety, and (2) repair/maintenance. The EPA is
not reopening the other two situations listed. Specifically, the EPA is
proposing changes to the following regulatory text only: 40 CFR
60.5377b(d)(1) and (2), and 60.5391c(c)(1) and (2). To view the
proposed changes, see the full redline strike out (RLSO) of the
regulatory text located in the public docket at EPA-HQ-OAR-2024-0358.
2. Petitioner's Concerns and Supporting Information
The EPA received a petition for reconsideration of the March 2024
final rule from API-AXPC \16\ that included support for the EPA's
general approach finalized at 40 CFR 60.5377b(d) that allows temporary
flaring of associated gas for unique situations. However, petitioners
highlighted that there are certain oil and natural gas production
operations that are remote and spread out over many miles that are
prone to severe winter weather events that could prevent operators from
accessing these remote sites for longer than 24 hours. They provided,
for example, that seasonal weather in North Dakota may cause local
agencies to close roads whereby people and equipment would be prevented
from arriving at a location within 24 hours. They requested that the
EPA extend the temporary flaring provisions for malfunction and repair
or maintenance activity to 72 hours from 24 hours as finalized. They
added that the March 2024 final rule's specific timing restrictions for
flaring were not in the proposals and therefore they did not have the
opportunity to comment on the timelines finalized.
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\16\ April 2024 API and AXPC petition.
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The petitioners added that the March 2024 final rule preamble
includes language that they believe indicates that the EPA intended to
allow up to 72 hours for temporary flaring, ``. . .during repair,
maintenance including blowdowns, a packer leakage test, a production
test, or commissioning.'' \17\ Petitioners asking the EPA to reconsider
this issue interpreted that it was the EPA's intention that 72 hours be
allowed for temporary flaring, ``. . . during repair, maintenance
including blowdowns, a packer leakage test, a production test, or
commissioning,'' based on language in the final rule preamble.
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\17\ 89 FR 16820, at 16949.
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However, the EPA is now clarifying that the language cited by
Petitioners was an inadvertent error. Elsewhere in the final rule
preamble (e.g., Table 17--Situations and Durations where Associated Gas
May Temporarily be Routed to a Flare or Control Device) and the final
rule regulatory text correctly specify 24 hours as the allowance for
temporary routing to a flare or control device during repair and
maintenance. The final rule does allow for up to 72 hours in a
different scenario, if associated gas does not meet pipeline
specifications. In the March 2024 final rule, the EPA did not intend,
and the existing regulatory text does not permit, to allow up to 72
hours for repair and maintenance.
As a follow-up to their petition, API conducted a survey \18\ from
June through July 2024 with its members to understand the distribution
of temporary associated gas flaring duration due to malfunction or
maintenance and repair and submitted to the EPA for consideration. The
API survey-provided responses include information on duration, data
(month and year), and cause of temporary flaring events due to
malfunction or maintenance or repair based on readily available data
collected over 6 years (with 70 percent of the data collected within
the last 3 years). The API survey data set represents over 2,800 total
data points from six operators across three basins. The majority of the
information (92 percent of the data points) was from the Permian Basin,
with 6 percent and 2 percent from the Williston and San Juaquin Basins,
respectively. Overall, according to API, the results indicate that over
17 percent of events across the three basins required temporary flaring
greater than 24 hours per event and over 15 percent of events required
temporary flaring greater than 72 hours per event. Broken down by
basin, 12 percent of the events in the Permian Basin required temporary
flaring greater than 24 hours, and 11 percent required flaring
durations greater than 72 hours. For the Williston Basin, 92 percent of
events required flaring for greater than 24 hours and 78 percent
required flaring for greater than 72 hours. For the San Joaquin Basin,
7 percent of events required flaring greater than 24 hours and 0
percent required flaring greater than 72 hours. The average duration of
a temporary flaring event for all basins was reported to be 46 hours.
The average flaring event durations by basin were 26 hours for the
Permian Basin, 378 hours for the Williston Basin, and 8 hours for the
San Joaquin Basin. API reported that inclement weather is one of many
factors that contributes to the need for longer temporary flaring
durations, which is reflected in the longer durations in the Williston
Basin.\19\ They concluded that the data set supports their position
that a 24-hour limit is a potential issue across various causes of
temporary flaring including planned events, with geographically
dispersed sites presenting additional challenges to rapid response.
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\18\ API (Prepared for API by John Beath Environmental, LLC).
Operator Survey: Temporary Flaring. Slide Presentation and Excel
Workbook. July 2024.
\19\ The Williston Basin spans western North Dakota,
northwestern South Dakota, eastern Montana and into a southern
section of Canada.
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Additional takeaways from the survey data, according to API, are
that: (1) Operators are already making efforts to reduce the duration
of temporary flaring, with approximately 83 percent of flaring events
represented in the data set being less than 24 hours; and (2) API
believes that a 72-hour flaring limit would be more realistic, force
operational innovation, minimize emissions, and would reduce the
duration of roughly 15 percent of events. API acknowledged that
although the results of the survey may not be statistically
representative of the entire population (the entire industry in terms
of all wells with associated gas), they believe that the collected data
indicates that 72 hours is more appropriate than 24 hours as a national
standard for temporary flaring due to malfunction or planned repair and
maintenance.
The EPA had also received a briefing by Hess Corporation prior to
receiving the April 2024 API and AXPC petition on temporary flaring
concerns.\20\ Their briefing stressed that well sites are unmanned
facilities that are spread over hundreds of miles throughout North
Dakota. They stressed that seasonal conditions such as road
restrictions in spring and fall and extreme winter conditions can
prevent personnel and equipment from getting to site, and that it may
take days and up to over a week until access roads to a well site are
cleared of snow. They added that, if a maintenance crew is required for
repair, it can take multiple days even with equipment available. They
suggested that it would be more appropriate and achievable for the EPA
to allow 72
[[Page 3740]]
hours for temporary flaring due to safety and repair conditions.
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\20\ Hess Briefing for the EPA: Oil and Natural Gas Final
Methane Rule NSPS OOOOb and EG OOOOc. February 29, 2024, Slide
Presentation. See slides 19-23.
---------------------------------------------------------------------------
Hess Corporation provided two specific scenarios in their briefing
that they believe would require the need for flaring greater than 24
hours: (1) Back pressure valve (BPV) failure; and (2) frozen sales gas
piping on well site. Under the first scenario, they reported that it
can take over a week to fix a BPV where an operator cannot fix it
without involving others to perform corrective work and to obtain the
necessary parts. Under the second scenario, once a freeze is
identified, mitigation needs to be scheduled with a 3rd party and work
can entail over a day to remove snow to provide access to thaw piping.
In June of 2024, Hess Corporation presented an updated briefing
\21\ to the EPA on their concerns related to the temporary flaring
provisions which included additional supporting information for the
above-mentioned scenarios. For example, for the first scenario above,
Hess provided BPV failure notification to resolution timeline data
indicating that it takes anywhere from a half day to 8 days (with an
average resolution time of 3.2 days). Hess emphasized that weather-
related closures/restrictions that prevent personnel and repair
equipment from getting to a site, and well sites in North Dakota that
are unmanned facilities spread over hundreds of miles are both
instances that would prevent maintenance and repair within 24 hours as
required by the March 2024 final rule. Hess represented that their
operations in North Dakota span an area of roughly 7,200 square miles.
Thus, the company stated that even under normal business processes--
that incorporate efficiencies--maintenance and repair within 24 hours
is unlikely and infeasible in many instances, even without a reason
beyond an operator's control.
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\21\ Hess Briefing for the EPA: NSPS OOOOb Safety, Malfunction &
Repair Temporary Flaring Allowance. June 3, 2024. Slide
Presentation.
---------------------------------------------------------------------------
3. Summary of Proposed Changes
After consideration of the petitioners' concerns and supporting
information, the EPA is proposing to revise the temporary flaring
provisions for associated gas in certain situations finalized in the
March 2024 final rule. Specifically, these proposed revisions only
apply to situations during: (1) Malfunction/safety, and (2) repair/
maintenance. The EPA is proposing to extend the allowable time for
temporary flaring from 24 to 48 hours for malfunction, including for
reasons of safety, and during all repairs and maintenance.
Further, the EPA recognizes Petitioners' claim that there may be
some instances in which an owner or operator encounters a malfunction,
safety, repair, or maintenance event that requires routing to a flare
or control device beyond 48 hours. To address such instances, the EPA
is soliciting comment on allowing owners or operators of associated gas
affected facilities to route to a flare or control device for up to 72
hours if ``exigent circumstances'' exist. Such ``exigent
circumstances'' would include situations where an owner or operator
cannot physically access a site due to weather or other conditions
(e.g., road closures). In addition to extreme weather events/road
closures, the EPA is also soliciting comment on whether there are other
specific ``exigent circumstances'' where the EPA should consider
allowing an owner or operator to include as a basis of a ``exigent
circumstance'' claim requiring the need to route to a flare or control
device beyond the proposed 48-hour allowance for repairs and
malfunctions. The EPA also solicits comment on the records and reports
that should be required if the EPA were to include an allowance for
owners or operators of associated gas affected facilities to route to a
flare or control device for up to 72 hours for ``exigent
circumstances.'' Specifically, the EPA solicits comment on requiring an
owner or operator who must make use of the extended timeframe to
maintain records that include: (1) A written description of the
``exigent circumstance''; (2) the rationale for the need to route to a
flare or control device beyond 48 hours; (3) a description of the
measures taken to minimize temporary flaring/routing to a control
device; and (4) the duration of temporary flaring/routing to a control
device due to the identified ``exigent circumstance.'' Lastly, the EPA
solicits comment on requiring an owner or operator to include a summary
of their annual ``exigent circumstance'' recorded events in their
annual report.
The basis for the EPA's proposed changes and solicitations is
discussed in III.A.4 of this preamble.
4. Basis for Proposed Changes
The March 2024 final rule allows temporarily routing associated gas
to a flare or control device for 24 hours during situations where a
malfunction or incident endangers the safety of operator personnel or
the public, and during repair, maintenance including blow downs, a
production test, or commissioning. These provisions were based on
requirements of existing State rules, information from the World Bank
Global Flaring and Methane Reduction Partnership, and specific
recommendations provided by comments received on the proposal and
supplemental proposal.\22\
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\22\ 89 FR 16943 to 16944 and 89 FR 16948 to 16950.
---------------------------------------------------------------------------
As discussed in section III.A.2 of this preamble, industry
petitioners indicated that the 24-hour limitation for temporary routing
to a flare or control device in the final rule during situations where
a malfunction or incident endangers the safety of operator personnel or
the public, and during repair, maintenance including blow downs, a
production test, or commissioning, is not sufficient. They claim that a
72-hour timeframe for all these situations is more appropriate for
temporary routing to a flare or control device due to the unique
characteristics of some well sites, weather conditions, or a
combination of both.
The EPA considered this information, and examined the scenarios
provided by the petitioners where they claimed there was a need for
temporary routing to a flare or control device beyond 24 hours. First,
the information provided by petitioners is persuasive in demonstrating
that a blanket 24-hour limit on temporary flaring can pose compliance
challenges for certain owners and operators. While we still expect that
owners and operators can feasibly limit temporary flaring to less than
24 hours in a large majority of situations (and this is supported by
the API survey data cited above), we acknowledge that in certain
instances, fundamental aspects of well site operational schedules can
make this requirement challenging, particularly for remote unmanned
sites. The EPA understands that owners' and operators' operational
schedules outline the staffing and work shifts of oil and gas
operations, ensuring that personnel are available to monitor and
respond to issues within a designated timeframe while maintaining safe
and efficient operations. We recognize that challenges arise when
problems occur outside of an operator's working hours, such as during
night shifts, shift changes or when fewer staffs are present leading to
delays in identifying and addressing repairs and malfunctions. Hess has
shared information with the EPA highlighting how the 24 hour
operational schedule may not be sufficient for quick response in such
cases, particularly with the remote
[[Page 3741]]
nature of these sites.\23\ We also recognize that the gathering of
available parts and prioritization of corrective work to correct a
situation, such as the BPV failure example cited by Hess, could require
the need for routing to a flare or control device for a period greater
than 24 hours. Further, we also recognize that circumstances outside of
the control of the owner/operator, such as weather events, can also
impact the ability to address the situation within 24 hours.
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\23\ An example of the timeline challenges with well site
operational schedules is presented in slide 5 of Hess Briefing for
the EPA: NSPS OOOOb Safety, Malfunction & Repair Temporary Flaring
Allowance. June 3, 2024. Slide Presentation.
---------------------------------------------------------------------------
However, the EPA believes at this time that proposing to change the
requirement to allow temporary routing to a flare or control device for
up to 48 hours is likely to address most of the issues raised by the
petitioners. We maintain that equipment needs for failures should be
planned for in advance to minimize routing to a flare or control device
(i.e., owners and operators should plan to have equipment on hand for
failures on site), and that additional time beyond 48 hours should not
be necessary to address issues at remote sites since these sites are
typically accessible within a 24 hour period (except during certain
conditions e.g., seasonal weather, road closures that may prevent
operators from accessing the site). Therefore, we are proposing to
double the time frame for which temporary routing to a flare or control
device is allowed during situations where a malfunction or incident
endangers the safety of operator personnel or the public, and during
repair, maintenance including blow downs, a production test, or
commissioning, from 24 hours per event to 48 hours per event. This
timeframe is supported by API's survey, which found the average
duration of temporary flaring was 46 hours per event.
While the EPA is proposing to change the allowed duration for
temporarily routing associated gas to a flare or control device from 24
to 48 hours, we recognize that there is some information that could
support retaining the 24-hour time frame. As noted above, the API
survey indicated that 83 percent of the circumstances encountered that
required temporary flaring were resolved in 24 hours or less. Further,
Colorado 2 Colo. Code. Regs. sec. 4041:903 allow gas to be flared (or
vented during an upset condition), but for a period not to exceed 24
cumulative hours per event. In addition, information from New Mexico
\24\ indicates that only 11 percent of the total volume of gas flared
(from all sources, not only associated gas) results from flaring
activities with durations greater than 8 hours. We request information
and data on whether the proposed temporary flaring duration of 48 hours
has the potential to increase the amount of primary or secondary
emissions. The duration of flaring will vary by basin and by the reason
for flaring. We request that any data on changes in emissions due to
flaring specifically identify the basin, reasons for flaring, and
duration of the temporary flaring. We request that commenters consider
this information in submitting comments related to the proposed change
to 48 hours. We also request additional information to support the
proposal, or to support retaining the 24-hour period in the final rule.
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\24\ https://wwwapps.emnrd.nm.gov/OCD/OCDPermitting/Reporting/NaturalGasWaste/UpstreamNaturalGasWasteSummaryReportExpanded.aspx.
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While the EPA expects that the vast majority of temporary flaring
situations can be addressed within the 48-hour timeframe proposed in
these amendments, we recognize that incidents might not be resolved
within 48 hours due to circumstances beyond an owner or operator's
control. Examples of such ``exigent circumstances'' mentioned by the
petitioners include road closures and seasonal weather that could
prevent operators from accessing the site to conduct a necessary
repair. As discussed above, EPA is not proposing to allow temporary
flaring beyond 48 hours during such circumstances; however, we are
soliciting comment on the need to allow routing to a flare or control
device for up to 72 hours where a legitimate and supported ``exigent
circumstance'' claim is made. We solicit comment on what would
constitute an exigent circumstance and defining these incidences.
Relatedly, we are soliciting comment on the potential ``exigent
circumstances'' recordkeeping criteria explained above, and on when an
``exigent circumstance'' claim should be sent to the Agency (in the
annual report or otherwise). This longer time frame of up to 72 hours
for special situations is consistent with the duration recommended by
reconsideration petitioners. We acknowledge that such circumstances
represent real-life scenarios that are beyond an owner or operator's
control but seek more information on this as an option. See section
III.A.3 of this preamble for more explanation on our solicitation for
information.
B. Vent Gas Net Heating Value (NHV) Continuous Monitoring Requirements
and Alternative Performance Test (Sampling Demonstration) Option for
Flares and Enclosed Combustion Devices
A summary of the relevant promulgated provisions being reconsidered
related to the vent gas NHV continuous monitoring requirements and
alternative performance test (sampling demonstration) option for flares
and enclosed combustion devices is presented in section III.B.1, and
specific concerns and supporting information provided by petitioners
and other industry representatives are presented in section III.B.2 of
this preamble. After consideration of the petitioners' concerns and
supporting information, the EPA is proposing certain discrete changes
to these particular requirements finalized in the March 2024 final
rule. The proposed changes are presented in section III.B.3 of this
preamble and the EPA's rationale for those proposed changes is
presented in III.B.4 of this preamble.
1. Summary of Promulgated Provisions Being Reconsidered
The EPA finalized compliance requirements for continuous monitoring
and initial and periodic performance testing for flares and enclosed
combustion devices in the March 2024 final rule. Of relevance to this
proposal are the final requirements for those two control devices
regarding the NHV monitoring requirements and alternative performance
test (sampling demonstration) option. In the March 2024 final rule,
with exceptions for catalytic vapor incinerators, boilers and process
heaters, and enclosed combustors where temperature is an indicator of
destruction efficiency, all flares and enclosed combustors must
maintain the NHV of the gas sent to the device above a minimum NHV
value if the combustion device is pressure-assisted or uses no assist
gas. If an owner or operator uses a steam- or air-assisted enclosed
combustion device or flare, the owner or operator must maintain the
combustion zone NHV (NHVcz) above a minimum level. If the
owner or operator uses an air-assisted enclosed combustion device or
flare, the owner or operator must maintain the NHV dilution parameter
(NHVdil) above a minimum level. The NHVcz and
NHVdil parameter terms account for the reduction in heating
value caused by the introduction of air or steam. These
[[Page 3742]]
terms ensure that the assist gas does not overwhelm the heating value
provided by the vent gas to the point where proper combustion is no
longer occurring. Owners or operators also have the option to apply to
use an alternative test method that either demonstrates continuous
compliance with the combustion efficiency limit or directly
demonstrates continuous compliance with the NHVcz operating
limit and, if applicable, the NHVdil operating limit.
Associated gas from a well site affected facility was exempt from
NHV monitoring (i.e., assumed to always have high NHV) under the March
2024 final rule. For each enclosed combustor and flare used to control
gases other than associated gas from a well site affected facility, the
owner or operator must conduct continuous monitoring using a
calorimeter, gas chromatograph (GC), or mass spectrometer (MS) in order
to determine the NHV of the vent stream. As an alternative to
continuous monitoring of NHV, the owner or operator may conduct a
performance test to demonstrate the NHV of the vent stream consistently
exceeds the applicable NHV operating limit in one of two ways: (1)
Continuous sampling for 14 consecutive days plus ongoing (3 samples
every 5 years) sampling, or (2) manual sampling (twice daily for 14
consecutive days) plus ongoing (3) samples every 5 years) sampling. The
minimum collection time for each individual manually collected sample
must be at least one hour. If inlet gas flow is intermittent such that
collecting 28 samples in 14 days is infeasible, an owner or operator
must continue to collect samples beyond 14 days in order to collect a
minimum of 28 samples. Owners or operators also have the option to use
an alternative test method 25 26 that demonstrates
continuous compliance with the combustion efficiency limit; if there
are no values of the combustion efficiency measured by the alternative
test method over the 14-day period that are less than 95 percent, the
gas stream is considered to consistently exceed the applicable NHV
operating limit and the owner or operator is not required to
continuously monitor or conduct sampling of the NHV of the inlet gas to
the enclosed combustion device or flare. Owners or operators of steam-
assisted and air-assisted enclosed combustors and flares also must
monitor the vent gas and assist gas flow rates and calculate
NHVcz and NHVdil in accordance with the
provisions in 40 CFR 63.670 (i.e., the refinery maximum achievable
control technology rule, or Refinery MACT). Alternatively, owners or
operators of air-assisted flares may provide a one-time demonstration
based on maximum air assist rates, minimum waste gas flow rates (based
on back pressure regulator setting), and minimum NHV from the most
recent sampling rather than continuously monitor vent gas and assist
gas flow rates.
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\25\ Under the provisions outlined in 40 CFR 60.5412b(d) and
60.5415b(f)(1)(xi), sources can request to use an ``equivalent
method'' pursuant to 40 CFR 60.8(b)(2), or ``an alternative method
the results of which [the Administrator] has determined to be
adequate for indicating whether a specific source is in compliance''
pursuant to 40 CFR 60.8(b)(3). The EPA is currently accepting and
reviewing applications for alternative (ALT) test methods for NHV
monitoring in the oil and natural gas sector. See https://
www.epa.gov/emc/oil-and-gas-alternative-test-
methods#:~:text=The%20application%20portal%20can%20be,Air%20Emission%
20Measurement%20Center%20web page. Since the rule's publication date
of March 8, 2024, two alternative test method requests have been
approved by the EPA for use under NSPS subpart OOOOb: (1) ALT-156
Alternative Test Method to monitor the NHV of the flare combustion
zone at facilities Subject to NSPS OOOOb and (2) ALT-157 Alternative
Test Method for determining NHV from gas sent to an ECD or Flare
subject to NSPS OOOOb. A list of the EPA's approved alternative test
methods can be found at https://www.epa.gov/emc/broadly-applicable-approved-alternative-test-methods.
\26\ Per 40 CFR 60.8(b)(5), the EPA has more general authority
to approve alternative test methods involving ``shorter sampling
times and smaller sample volumes when necessitated by process
variables or other factors.''
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Finally, as discussed in section II.B of this preamble, the EPA
issued a letter on May 6, 2024, whereby the EPA clarified performance
testing deadlines with respect to the alternative NHV sampling
demonstration that owners or operators must meet in order to
demonstrate compliance with the applicable NSPS subpart OOOOb emission
standard. The EPA stated that as applied to the March 2024 final rule,
affected sources that were new, modified, or reconstructed after the
supplemental proposal (December 6, 2022), but before the rule's
effective date of May 7, 2024, have 180 calendar days after the
effective date of the rule to conduct performance (i.e., compliance)
testing. For NSPS subpart OOOOb sources that are new, modified or
reconstructed after the final rule's effective date of May 7, 2024, the
applicable monitoring requirements (including the 14-day NHV
performance test) must be completed within 180 calendar days after
initial startup of the source.
2. Petitioners' Concerns and Supporting Information
API and AXPC 27 28, TXOGA \29\, GPA Midstream \30\, and
EIP \31\ raised issues in their petitions relating to the March 2024
final rule requirements for the NHV compliance demonstration, which
consists of either monitoring the NHV content of the vent gas on a
continuous basis, or utilizing the alternative performance test option.
The April and May 2024 API and AXPC petitions, May 2024 TXOGA petition,
and May 2024 GPA Midstream Association petitions raised issues
regarding the need for the NHV compliance demonstration, technical
infeasibility of the demonstration, and compliance timing (including
supply chain issues). The May 2024 EIP, et. al. petition contended that
the EPA did not support its conclusion in the March 2024 final rule
that initial assessments of flares and other control devices, in lieu
of continuous monitoring, can capture the variability of NHV in the oil
and gas sector, and that no sampling or monitoring of NHV is needed
when only associated gas from wells is sent to control devices.
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\27\ April 2024 API and AXPC petition.
\28\ May 2024 API and AXPC petition.
\29\ May 2024 TXOGA petition.
\30\ May 2024 GPA Midstream petition.
\31\ May 2024 EIP, et al. petition.
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a. Need for NHV Compliance Demonstration
The April and May 2024 API and APXC and May 2024 GPA Midstream
petitions state that vent gases in this industry are not expected to
fall below the minimum NHV unless diluted by inert gases,\32\ and
therefore the NHV requirements in the March 2024 final rule are
unnecessary. The May 2024 GPA Midstream petition raised concerns with
operations in the midstream and stated that waste gas streams routed to
combustion devices have very high British thermal unit (Btu) values,
when compared to the minimum NHV values finalized in the March 2024
final rule, because these midstream gas streams consist of natural gas
and field gas with NHVs typically in excess of 1,000 Btu/standard cubic
feet (scf). Further, this petitioner stated that inert gases, such as
nitrogen, are rarely used at midstream sources and any water in the gas
is eliminated well before the control device. This petitioner also
cited to prior responses to public comments
[[Page 3743]]
from the EPA which acknowledged the NHV of the vent gas to a flare in
this sector is likely to be well above the minimum required NHV \33\
and questioned what it perceived as a change in the EPA's position \34\
in the March 2024 final rule. In a letter \35\ to the EPA dated July
31, 2024, GPA Midstream provided additional information, not previously
provided during the course of the prior rulemaking, regarding operating
scenarios in midstream operations where vent gases may have a lower NHV
than typical gathering, boosting, and processing operations. In this
same letter, GPA Midstream also provided new NHV data from gathering,
boosting, and processing vent gas streams routed to controls, along
with four new operating scenarios for the EPA's consideration, where
the NHV content in vent gas streams may be lower than normal:
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\32\ For the purposes of the NHV compliance provisions, inert
gases (or inerts) are gases that do not readily undergo combustion.
Inert gases consist of or contain high concentrations of nitrogen,
carbon dioxide (CO2), water, or other compounds that have
a net heating value of zero.
\33\ See RTC, Response II-17-46 and II-17-47.
\34\ See 89 FR 16966.
\35\ GPA Midstream--EPA 06/24/24 Meeting Follow-Up. Re: Response
to EPA Request for Additional Information regarding OOOOb GPA
Midstream Net Heating Value Case Scenarios and Data. (Attachment
Summarizing NHV Data Included as an Attachment). Hereinafter
referred to as the ``July 2024 GPA Midstream Letter.''
---------------------------------------------------------------------------
1. Combining acid gas removal (AGR) system amine regenerator still
column vent gas with affected facility vent gas streams--GPA Midstream
explained that AGR amine regenerator still column vent gases typically
are routed to an individual control device due to the low flow rate,
low pressure, and corrosive nature of the vent stream, and that the low
NHV of the stream typically requires supplemental gas for proper
control device operation. However, GPA Midstream explained it is
possible to combine the still column vent gas with other vent gas
streams, which would lower the NHV of the combined stream, primarily
due to the high CO2 content of the still column vent gas.
2. Combining glycol dehydration unit reboiler vent gas with
affected facility vent gas streams without water removal--GPA Midstream
explained that typically glycol dehydration unit reboiler vent gas is
routed through a condenser to remove liquids (including VOC and water
vapor) and then routed to a process or control device. However, it is
possible to combine the glycol dehydration unit reboiler gas, without
routing through a condenser, with other vent gases routed to common
control. The high water content of the reboiler vent gas stream could
lower the NHV of the combined vent gas streams.
3. Use of inert gases and entrainment in affected facility vent gas
stream--GPA Midstream explained that midstream operations usually do
not employ the use of inert gases such as nitrogen because if a blanket
gas is needed, its midstream operations use natural gas as it is
readily available and compatible with control devices due to the high
NHV. In instances where an inert gas such as nitrogen is used as a
blanket gas, this could cause lower NHV of the vent gas stream.
4. High water content in vent gas streams from storage vessels--
Finally, GPA Midstream explained that midstream operations employ the
use of storage vessels for storing hydrocarbons and produced water,
which typically have NHVs well above the thresholds required by the
March 2024 final rule. However, it is possible that some production
areas could have higher water content in the vent stream coming from
the storage vessels, which would lower the NHV. GPA Midstream notes
that in these cases, the high water content would increase the
probability that the storage vessel emissions thresholds for
applicability would not be exceeded. In any event, GPA Midstream
explained that in such scenarios, the NHVs are still above the lower
NHV thresholds of the rule.
GPA Midstream summarized that midstream operators would be aware of
the operating scenarios provided and should be allowed to use process
knowledge to assess whether the NHV could not meet the requirements of
the March 2024 final rule, and thus would require the use of
supplemental gas.
GPA Midstream also provided a new data set \36\ of sampled data and
modeled data from midstream operations, stating that the data indicate
that the vent gas streams are well above the NHV requirements of the
rule and hence should not require continuous NHV monitoring. GPA
Midstream further explained technical difficulties in collecting the
data, which are described in section III.B.b of this preamble.
---------------------------------------------------------------------------
\36\ July 2024 GPA Midstream Letter.
---------------------------------------------------------------------------
The April 2024 API and AXPC petition referred to an NHV data set
\37\ that they provided to the EPA after publication of the March 2024
final rule which included over 22,000 data points from 18 operators
across approximately 4,200 sites. The petitioners stated that this data
set showed that more than 99.5 percent of the time NHV values were at
least 800 Btu/scf and more than 99.9 percent of the time the NHV value
was at least 300 Btu/scf. API and AXPC further stated that the results
appeared consistent across five basins, representing 99 percent of the
data. While some sources with multiple data points showed variability,
the NHV was still well above 800 Btu/scf for those sources. API and
AXPC stated that all NHV data <= 900 Btu/scf in the survey were from
known scenarios where large amounts of inert gas(es) are expected. The
petitioners stated that operators know which scenarios or sites have
the potential for large amounts of inert gases to reduce the NHV of
vent streams below the required minimum; these known scenarios include:
(1) Sites in fields using water or CO2 flood Enhanced Oil
Recovery (EOR), and (2) produced water tanks not co-located with oil
tanks in certain dry gas plays.
---------------------------------------------------------------------------
\37\ API/AXPC-EPA 03/18/24 Meeting Follow-Up. Operator Survey:
Net Heating Value. API-AXPC Meeting Slide Presentation to the EPA.
(Attachment Summarizing NHV Data Included as an Attachment. Excel
Sheet Provided of Analysis of NHV Data Provided by Operators:
Supporting Data (Prepared by John Beath Environmental, LLC for API/
AXPC).)
---------------------------------------------------------------------------
The April 2024 API and AXPC petition also included a letter from
SPL, which stated it is the largest laboratory in the United States
(U.S.) specializing in the analysis of hydrocarbon products, processing
more than 225,000 natural gas samples each year. SPL stated that based
on its direct experience analyzing thousands of vent gas samples from
every major oil and gas producing region of the U.S. annually, it would
be exceptionally uncommon for the NHV content of vent gas to fall below
the threshold levels established by the March 2024 final rule. SPL
explained that vent gases are exceptionally heavy gases (relative to
air) that are typically depleted with respect to lighter hydrocarbon
molecules such as methane and ethane, and enriched in molecules like
propane, butane and pentane. As a result, SPL explained that these
heavy gases have a lower vapor pressure (relative to a methane-enriched
sales gas, for example) and therefore do not ``flash'' from the liquid
hydrocarbon stream until the final stage of separation. The vendor
provided NHV data for methane (909.4 Btu/ft\3\), propane, n-butane and
n-pentane (2,315 Btu/ft\3\, 3,000 Btu/ft\3\ and 3,707 Btu/ft\3\
respectively).\38\ Therefore, SPL explained that, unless there is a
source of inert gas diluting the vent gas stream (sources of inert gas
could be added by design, or, due to leaking equipment), there should
be no compositional reason the NHV of that gas would be under the
threshold set by the EPA.
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\38\ See: GPA 2145--``Table of Physical Properties for
Hydrocarbons and Other Compounds of Interest to the Natural Gas
Industry.''
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b. Technical Infeasibility
The April and May 2024 API and AXPC petitions, May 2024 TXOGA
[[Page 3744]]
petition, and May 2024 GPA Midstream petitions raised new issues
regarding the feasibility of conducting the sampling for the
alternative NHV performance test (sampling demonstration), given the
intermittent flow to control devices. The petitioners explained that in
some cases, flow to the control device may occur for as little as a few
minutes, making continuous monitoring or collection of single (or 28)
one-hour samples impossible. The May 2024 TXOGA petition also explained
that sampling equipment is not designed to operate in low temperatures
or with all types of gases.
The April 2024 API and AXPC petition pointed out that while the
March 2024 final rule reduced the number of required samples from 240
(as proposed in the December 6, 2022 supplemental rule) to 28, it did
not address the feasibility of collecting the samples. API and AXPC
also contended that extending the sampling duration from 10 to 14 days
added time and costs to an already technically infeasible option. As
noted above, these petitioners submitted information from SPL, a
laboratory that stated that the minimum one-hour sampling requirement
in the alternative performance test (sampling demonstration) option
goes against traditional norms for the collection of natural gas grab
samples and requires all sampling entities to deploy alternative
strategies which are not currently available. SPL explained that
typical methods for the collection of natural gas samples call for spot
sampling techniques that procure gas on very short (seconds to minutes)
timescales, but the one-hour requirement requires composite sampling
techniques typically used in custody-transfer applications (and
elsewhere) to be adapted to a more rugged and transportable setup. SPL
suggested that the EPA allow sample collection methods such as those
referenced in GPA 2166-22 instead. SPL also pointed out what it
considered to be several issues with the use of Summa canisters for
vent gas collection. SPL explained that Summa cannisters were designed
primarily for atmospheric gas sampling and that in order to collect 1-
hour samples by Summa cannister, restrictive flow metering devices will
be required, which rely on a restrictive orifice to meter the gas into
the Summa cannister. SPL explained that the potentially wet and dirty
nature of flare gas will rapidly foul these devices, resulting in
errors in collection and potential contamination bias. Instead, SPL
recommended that, for operators and laboratories to meet sample demand
in a reasonable manner, single cavity stainless steel constant volume
cylinders should be allowed for sample collection so long as they are
maintained according to the requirements set forth in 43 CFR 3175
(Onshore Oil and Gas Operations; Federal and Indian Oil and Gas Leases;
Measurement of Gas).
The May 2024 GPA Midstream petition explained that vent gas flow
from midstream sources to control devices tended to be sporadic and at
low pressure. They stated that intermittent flow was particularly an
issue for storage vessels that either have low flows generally or have
pressure control valves that only release short bursts of gas to
control devices. GPA Midstream stated it is not possible to achieve the
necessary flow rate for establishing a temperature limit, continuous
monitoring, or one-hour sampling without adding gas pressure. It
further explained that storage vessels will frequently be unable to add
sweep gas because the necessary headspace is limited; in situations
where facilities add gas, those situations will not be representative
of normal operating conditions. In the July 2024 GPA Midstream letter,
GPA Midstream provided further examples of sample collection issues. In
addition to the availability of sampling ports, discussed below, GPA
Midstream noted that closed vent systems (CVS) operate under a slight
vacuum or close to atmospheric pressure and temperature, which can draw
oxygen (O2) in with the vent stream sample. Also, because
vent gas samples are obtained at atmospheric pressures, explained GPA
Midstream, running the vent gas samples through the GC upon capture
causes issues due to liquids (e.g., water) condensing during analysis,
which often requires repairs to the GC.
The April 2024 API and AXPC petition contended that NHV monitoring
is not required in existing State regulations governing upstream flares
and combustion emissions control devices and that upstream operators
are not currently conducting NHV monitoring for operational or other
non-regulatory reasons.\39\ Thus, the petitioners argued that the NHV
monitoring at upstream flares and combustion emissions control devices
has not been demonstrated to be feasible or cost-effective.
---------------------------------------------------------------------------
\39\ API and AXPC specifically point to Colorado and New Mexico
as examples.
---------------------------------------------------------------------------
The April 2024 API and AXPC petition also expressed concerns that
the Refinery MACT-based NHVcz and NHVdil
requirements for devices which use steam- and air-assist and perimeter-
assist air, respectively, are overly burdensome because well sites,
central production facilities, and compressor stations are
fundamentally different than petroleum refineries. The petitioners
explained that the oil and natural gas production sector does not
operate at steady state conditions and equipment design must be
tailored to the conditions and fluid compositions supplied by the
reservoir. They added that hydrocarbon fluids (including oil,
condensate, and produced water) and natural gas are located thousands
of feet below the surface and must flow to the surface for separation.
API and AXPC explained that separation occurs in either a two- or
three-phase separator with intermittent pulses of produced water sent
from the bottom of the separator to its storage vessel, hydrocarbon
liquids from the middle to its storage vessel, and natural gas off the
top of the separator to the gathering system. These petitioners further
explained that as production declines, management of liquids can mean
that flow to the storage vessel can vary from essentially zero to high
flow rates and quickly back to zero rapidly and often. According to the
petitioners, the same is true for how vapors from the storage vessel
will be expected to flow to a control device since emissions occur from
flashing and working losses as liquid periodically flows into the
storage vessel from the separator. The petitioners explained that this
highly variable, non-steady state flow requires equipment to be sized
much larger than ideal steady state conditions would dictate and makes
flow measurement infeasible. The petitioners also provided that the
cost for Refinery MACT controls and monitoring equipment at refineries
are $1 million or more, with major ongoing costs. The petitioners
explained that these costs will be much greater at upstream facilities
without the necessary utilities and instrumentation resources available
for a large complex facility such as a refinery and it is unclear
whether instrumentation that is available that would work reliably
under these varying operating conditions.
The April and May API and AXPC and May 2024 GPA Midstream petitions
also raised issues with the alternative test method approval process,
stating that alternative test methods are costly to implement (and
unlikely to be used by small operators) and take time for agency
approval (and which is related to issues regarding compliance timing
discussed in section IV.B.2.c of this preamble). The May 2024 GPA
[[Page 3745]]
Midstream petition requested that the EPA revise the March 2024 final
rule to allow alternative test methods for air and steam-assisted
combustion devices, such as Video Imaging Spectro-Radiometry (VISR), as
the March 2024 final rule preamble and regulatory text conflict with
respect to what is allowable. Specifically, the petitioner cited to 89
FR 16968, which indicates that ``an owner or operator could request an
alternative test method to use a technology such as VISR that
continuously monitors combustion efficiency or a technology such as
Simplified VISR that continuously monitors NHVcz and
NHVdil,'' but noted that the associated monitoring
requirements at 40 CFR 60.5417b(d)(8)(iii)(H) appear to not allow
alternative test methods to continuously monitor NHVcz and
NHVdil.
The May 2024 GPA Midstream petition also stated that the EPA should
allow for compliance demonstration alternatives. This petitioner
explained that design evaluations using process simulation software
will be more than sufficient for midstream sources to document that
waste streams consistently exceed the EPA's minimum NHV values. The
petitioner repeated prior comments to the EPA \40\, that owners and
operators can perform and document source-specific design evaluations
to demonstrate that waste gas streams will consistently exceed the
required minimum NHV thresholds in a manner similar to the evaluations
used for condensers and carbon absorption units under 40 CFR
60.5413b(c). If the EPA does not allow for compliance demonstration
alternatives, the petitioner requested that the EPA allow for
alternative sampling locations. In the July 2024 GPA Midstream letter,
GPA Midstream explained that prior to NSPS OOOOb, operators were not
required to collect NHV data because process knowledge would support
the vent stream as having a high NHV. Because of this, CVS were not
designed to include sampling ports. In addition to the compliance
timing reasons discussed in section IV.B.2.c of this preamble relating
to ``hot taps,'' the petitioner requested that the EPA allow sampling
from existing access points, such as thief hatches, which would avoid
the compliance timing issues, unnecessary costs, and creation of a new
opening that would be another potential source of fugitive emissions.
The petitioner also requested that owners or operators be able to draw
samples from storage vessel headspace, as there are always vapors
present in the vessel headspace and it will be representative of the
vent gas routed to the control devices.
---------------------------------------------------------------------------
\40\ See GPA Midstream Comments on the Supplemental Proposed
Rule (February 13, 2023) at 42-43. See Docket ID No. EPA-HQ-OAR-
2021-0317.
---------------------------------------------------------------------------
The May 2024 API and AXPC petition also requested that the EPA
require a re-evaluation of the of the vent gas stream NHV only when
there are process or equipment changes that could result in a lowering
of the NHV and requested that the EPA provide guidance regarding the
analytical methods required for NHV sampling. The petitioners noted
that the March 2024 final rule requires the use of American Society for
Testing and Materials (ASTM) Method D1945-14 for NHV analysis but
stated that this method is not widely available for well sites,
centralized production facilities, compressor stations, and gas plants
since it evaluates components not typically found in vent gas from
these operations (e.g., helium). The petitioners requested that the EPA
revise the March 2024 final rule, or at a minimum provide guidance, to
allow the use of GPA 2261 and other appropriate alternative methods to
measure NHV. In support of this, the petitioner provided information
from SPL, which stated that ASTM D1945-14 is not widely available and
will require additional time for method development, as well as
purchase or modification of equipment.
c. Compliance Timing
In addition to the compliance timing issues discussed above
relating to alternative test method approval and test method capability
development, the May 2024 GPA Midstream petition raised the issue that
the March 2024 final rule does not provide adequate time to conduct the
testing after such an approval is granted. The petitioner explained
that while 40 CFR 60.5412b(d)(1) through (5) provides requirements for
how the alternative test is performed, it provides no period of time by
which it should be performed, unlike 40 CFR 60.5413b(b)(5)(i) which
specifies that performance testing is required within 180 days after
initial startup. The petitioner further notes that unlike continuous
monitoring, which can be installed prior to startup of a new source,
the alternative testing protocol requires the combustion device to
already be operating in order to determine the destruction efficiency
and inspect of visible emissions. The petitioner is concerned that the
March 2024 final rule can be read so that any period of operation
before or during the alternative testing (dating back to December 2022
for modified sources) may be a deviation. The petitioner requests that
the EPA allow 30 days after startup to perform alternative testing.
The May 2024 TXOGA and April 2024 API and AXPC petitions expressed
concerns about the availability of sampling vendors that can perform
the sampling. The May 2024 TXOGA petitioner also pointed out that
finding viable sampling periods cannot be predicted due to the
intermittent flow to the devices. The April 2024 API and AXPC petition
estimated that a single sampling crew can typically visit no more than
two or three sites in a day due to the geographically dispersed nature
of upstream operations. This same petitioner provided statements from
SPL stating that the number of samples required would be greater than
the capacity of labs to collect and process in the 60-day window and
that there are not enough gas chromatographs, sample cylinders, and
human resources to make compliance within 60 days a possibility.
The May 2024 GPA Midstream petition raised concerns with the
feasibility of meeting compliance timelines for installation of
sampling ports. The petitioner stated that the EPA has underestimated
the number of sources that would be considered ``modified'' under the
Final Rule, resulting in the need to install monitors and sampling
ports on thousands of sources in an impracticably short time.\41\ The
petitioner stated that it will take owners and operators several months
to procure continuous monitoring equipment and installation will take
additional time. The petitioner provided purchase quotations from
vendors which indicated that calorimeters would take eight to 12 weeks
for delivery and continuous monitoring devices would take up to 26
weeks; installation would require an additional 2 to 3 weeks.
Additional concerns expressed by the May 2024 GPA Midstream petition
were that installation of monitoring equipment or sampling ports on
existing control devices requires specialized ``hot tap'' work, which
they stated cannot be accomplished across the industry prior to the
deadline for compliance demonstrations, due to a limited number of
qualified contractors and the
[[Page 3746]]
need to properly time unit shutdowns for the hot tap work.
---------------------------------------------------------------------------
\41\ See GPA Midstream Comments on Supplemental Proposed Rule at
37-38 (need for additional compliance time for storage vessels); 42
(discussing supply chain shortages contributing to long lead times).
See Docket ID No. EPA-HQ-OAR-2021-0317.
---------------------------------------------------------------------------
d. Other
The May 2024 EIP, et. al. petition contended that the EPA did not
support the March 2024 final rule conclusion that initial assessments
of flares and other control devices, in lieu of continuous monitoring,
can capture the variability of NHVs in the oil and gas sector and
asserted that no sampling or monitoring at all is needed when only
associated gas from wells is sent to control devices.
3. Summary of Proposed Changes
The EPA is proposing to revise numerous aspects of the NHV
monitoring and testing provisions in the March 2024 final rule. The EPA
is proposing to expand the streams that are exempt from monitoring due
to high NHV content to include unassisted flares or enclosed combustion
devices at new sources and to include unassisted, air-assisted, and
steam-assisted flares or enclosed combustion devices at existing
sources. We are proposing that the NHV monitoring that is currently
required should continue to be required for all pressure-assisted, air-
assisted, and steam assisted flares or enclosed combustion devices at
new sources and for pressure-assisted flares or enclosed combustion
devices at existing sources. We are proposing to remove the general
exemption from NHV monitoring for associated gas from well site
affected facilities for any control device. For flares or enclosed
combustion devices that are subject only to a minimum NHV content in
the vent gas of 200 Btu/scf or 300 Btu/scf, we are proposing to require
NHV monitoring only in cases where inert gases are added, or for other
miscellaneous scenarios which decreases the NHV content of the inlet
stream gas to the enclosed combustion device or flare. These known
operational scenarios include combining AGR system amine regenerator
still column vent gas with affected facility vent gas, combining glycol
dehydration unit reboiler vent gas with affected facility vent gas
streams without water removal, high water content in vent streams from
certain storage vessels, and EOR sites in fields using water or
CO2 flooding. The EPA is proposing recordkeeping and
reporting to indicate whether the flare or enclosed combustion device
receives inert gases or other streams which may lower the NHV of the
combined stream, and if so, a description of the operating scenario(s)
which may lower the NHV of the combined stream through the introduction
of those inert gases or other streams.
In addition, when an owner or operator opts to meet the NHV
compliance demonstration by conducting the alternative performance test
via the NHV grab sampling option, the EPA is proposing revisions to
clarify that sampling may be conducted on ``the inlet gas which is
routed to the enclosed combustion device or flare'' [emphasis denotes
proposed revision]. The EPA intends that this revised phrasing will
clarify that sampling upstream of the inlet to the control device is
allowed, provided that the sample is representative of the gas inlet to
the control device. For example, sampling may be conducted from a
location on the control device piping header, provided the sampling
location is downstream of all waste gas inlets into the header. The EPA
is proposing to clarify that the NHV of the vent stream shall be
determined in Btu/scf, where standard conditions are 20 degrees Celsius
([deg]C), not Btu per pound (Btu/lb). If the composition is determined
in weight percent, those concentrations can be used, but they will need
to be converted to volume percent (equivalent to mole percent) based on
the molecular weight of the constituents. Other changes in this
proposal include specifying that the 14-day period for the performance
test (sampling demonstration) option shall be consecutive operating
days and that for the purposes of determining the hourly average for
continuous samples, the average shall be a block hourly average. The
EPA is not proposing to amend the sampling frequency (i.e., 2 samples
per day for 14 days with an ongoing demonstration of 3 samples every 5
years) for the performance test (sampling demonstration) option for
neither NSPS OOOOb nor EG OOOOc. However, the EPA is proposing to allow
for breaks for weekends and holidays which may occur during the 14-day
sampling period, such that the 14 days do not have to be consecutive.
The EPA is also proposing to retain the one-hour minimum sampling time
for the twice daily samples, except in cases where low or intermittent
flow makes one-hour sampling infeasible. In such a case, the EPA is
proposing to allow less than one-hour sampling times and proposing that
the sampling time used and the reason for the reduced sampling time
must be documented and reported. The EPA is proposing to more clearly
allow the use of the sampling methodology alternative to continuous
monitoring in 40 CFR 60.5417b(d)(8)(iii) for all types of air and steam
assisted flares or enclosed combustion devices. The EPA is proposing
these same changes in both NSPS OOOOb and EG OOOOc.
In addition, for NSPS OOOOb, the EPA is proposing to retain the
NHVcz and NHVdil monitoring requirements, but
more clearly including the provisions at 40 CFR 60.5417b(d)(8)(vi) to
allow the use of approved alternative test methods as provided in 40
CFR 60.5412b(d)(1)(i) and (ii) for continuous monitoring of
NHVcz and, if applicable, NHVdil. We are also
proposing to more fully delineate in 40 CFR 60.5417b(d)(8)(iv) when
flare flow or assist rates are not required to be monitored. On the
other hand, for EG OOOOc, the EPA is proposing to remove the
requirement to comply with and conduct monitoring for NHVcz
and NHVdil for air- and steam-assisted enclosed combustion
devices and flares used for existing sources. This series of proposed
revisions in EG OOOOc include changes in the initial compliance
requirements for air- or steam-assisted enclosed combustion devices or
flares in 40 CFR 60.5412c, the continuous compliance requirements for
these control devices in 40 CFR 60.5415c, and the continuous monitoring
requirements for these control devices in 40 CFR 60.5417c. We are
proposing under EG OOOOc that air- or steam-assisted enclosed
combustion devices or flares must meet a minimum NHV in the vent gas of
300 Btu/scf.
4. Basis for Proposed Changes
a. Proposed Revisions to Inlet Gas Streams Exempt From Monitoring
As discussed in section III.B of this preamble, based on new
information provided by petitioners regarding NHV characteristics of
sample streams, the EPA is proposing changes to the requirements in the
March 2024 final rule that would, if finalized, expand the scope of the
exclusion for the NHV continuous monitoring requirements and
alternative performance test (sampling demonstration) option so that
the following control devices would not be required to make any such
demonstration: unassisted flares or enclosed combustion devices at a
new source and for unassisted, air-assisted, or steam-assisted flares
or enclosed combustion devices at existing sources. New data submitted
in the April 2024 API and AXPC petition demonstrated that, for over
22,000 NHV data points, 99.5 percent of those data points showed that
the NHV was at least 800 Btu/scf and more than 99.9 percent of those
data points showed that NHV was at least 300 Btu/scf. Notably, these
data were consistent across different
[[Page 3747]]
basins.\42\ Data supplied in the July 2024 GPA Midstream letter
supported their prior petition submittals that gas streams in the
midstream consist of natural gas and field gas with NHV values greater
than 1,000 Btu/scf, with the exception of certain streams in which
inert gases or other known low-NHV streams were added. Because these
new data appear to demonstrate that the NHV of the vent gas is
consistently well above the 200 or 300 Btu/scf vent gas requirements
for these control devices when inerts are not present, and because
there are no combustion zone or dilution parameters for these control
devices, the EPA is proposing to determine that an expanded exclusion
from the monitoring requirements is appropriate.
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\42\ 99 percent of the data were from five basins: Permian,
Anadarko, Gulf Coast (Eagleford), Williston (Bakken), and Powder
River. See March 18, 2024, API/AXPC Slides in Docket ID No. EPA-HQ-
OAR-2024-0358.
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While we previously excluded monitoring for associated gas from the
NHV compliance demonstration requirements, some petitioners have now
identified instances where the NHV for associated gas streams could be
compromised. Specifically, the use of water or CO2 flooding
EOR could introduce significant inerts as part of the associated gas
produced and thereby lower NHV of the associated gas. We find the
information presented by the petitioners compelling and therefore
propose to conclude that the March 2024 final rule's exclusion of
associated gas from the NHV compliance demonstration requirements is
overly broad. Because the definition of associated gas in the March
2024 final rule does specifically exclude these inert gases that may be
released with the natural gas during the initial stage of separation
after the wellhead, there are cases where associated gas can have high
levels of inerts and low NHV. Therefore, we are proposing to remove
this exclusion for associated gas in its entirety. The proposed removal
of this exclusion would impact pressure-assisted flares and enclosed
combustion devices at both new and existing sources and air- and steam-
assisted flares and enclosed combustion devices at new sources.
The EPA is not proposing to exclude pressure-assisted flares or
enclosed combustion devices from the NHV compliance demonstration
requirements. For pressure-assisted flares or enclosed combustion
devices, the required minimum NHV of 800 Btu/scf is not significantly
higher than the NHV of methane, which is 896 Btu/scf (using standard
conditions of 68 [deg]F (20 [deg]C); this value is lower than the value
provided by SPL because they used 60 [deg]F as standard conditions).
Therefore, sources that contain primarily methane would not require
much dilution from inert components (e.g., nitrogen, CO2, or
air) to be below the 800 Btu/scf NHV threshold for pressure-assisted
flares or enclosed combustion devices. While the data provided by
petitioners indicated that the majority of samples had NHVs above 800
Btu/scf, we find that it is much easier for the NHV in the vent gas
samples from these control devices to decrease and approach the 800
Btu/scf NHV threshold and that, therefore, continuous NHV monitoring or
an alternative performance test (sampling demonstration) is still
warranted for pressure-assisted flares or enclosed combustion devices.
Accordingly, we are proposing to retain the requirement that, as
currently required in the March 2024 final rule, pressure-assisted
flares must either continuously monitor NHV or conduct the 14-day
performance test sampling demonstration in order to ensure that the
gases sent to those control devices have NHVs well above the regulatory
threshold.
For reasons described in section III.B.4.d of this preamble, the
EPA is proposing to retain the NHVcz and NHVdil
requirements for air- and steam assisted flares for sources subject to
NSPS subpart OOOOb. Because these parameters are not only dependent on
the NHV of the vent gas but also on the flow rate of the vent gas and
the assist gas, we propose that the NHV demonstration is necessary
(when continuous monitoring is not used) to determine a minimum NHV to
use in the assessments under 40 CFR 60.5417b(d)(8)(iv) and in the
calculation of the NHVcz and NHVdil parameters in
40 CFR 60.5417b(d)(8)(vi).
As demonstrated by the July 2024 GPA Midstream data set, the
addition of inert gases or streams from amine units or produced water
tanks can decrease the NHV content of the gas stream to the point that
the minimum NHV thresholds for non-pressure-assisted flares or enclosed
combustion devices may not be achieved. In addition to sources of inert
streams previously identified in the March 2024 final rule (i.e.,
streams from compressors in acid gas service and streams from EOR
facilities), the July 2024 GPA Midstream letter explained that other
operating scenarios can result in the addition of low-Btu value streams
into the vent gas stream, which lowers the overall NHV for the vent
stream. Therefore, we are proposing to require NHV monitoring for
unassisted flares and enclosed combustion devices at new sources and
for unassisted, air-assisted, and steam-assisted flares and enclosed
combustion devices at existing sources in cases where there are
contributions from inerts. In the example cases provided in section
III.B. of this preamble, the EPA expects that these operational
scenarios can be easily validated through the physical presence (or
absence) of process equipment, process piping, engineering analysis, or
process flow diagrams in order to determine when the owner or operator
should monitor the NHV of the stream. For example, in the case of the
AGR system amine regenerator still column vent gas, it would be easy to
trace process piping to determine if the vent stream was routed to a
dedicated control device or was combined with affected facility vent
gas streams. Similarly, for the glycol dehydration unit reboiler vent
gas, the lack of a process condenser would indicate that higher water
content (and lower Btu) reboiler vent gas streams was combined with
affected facility vent gas streams. The use of nitrogen as a blanket
gas can be readily determined through the presence of nitrogen storage,
supply systems, and process piping. Finally, regarding vent streams
from storage tanks with higher water content, the EPA expects that
tanks with water content high enough to depress overall NHV values
typically would not meet the applicability thresholds of the rule and
would not be combined with other vent streams routed to an enclosed
combustion device or flare. However, when gas streams from produced
water tanks are vented to control, vent lines from these tanks can be
traced to identify sources that require monitoring or sampling.
Regarding the concerns raised in the May 2024 EIP, et. al.
petition, since we are proposing to remove the general monitoring
exemption for when the only inlet gas stream to the enclosed combustion
device or flare is associated gas from a well affected facility, we
directly resolve one of the issues raised in that petition. We consider
the data submitted by the industry petitioners to support the proposed
exemption from monitoring for flares and enclosed combustion devices
subject to a vent gas NHV requirement of 200 or 300 Btu/scf (and not
subject to NHVcz and NHVdil requirement) when no
inerts are present because the results were consistently much higher
than these levels. The May 2024 EIP, et. al. petition also contended
that the EPA did not support its conclusion in the March 2024 final
rule that initial assessments of flares and other control devices, in
lieu of continuous monitoring, can capture the
[[Page 3748]]
variability of NHV in the oil and gas sector. We consider the data
submitted by the industry petitioners also supports that the NHV
demonstrations required for pressure-, air-, and steam-assisted control
devices would be adequate data to show that the NHV from those
demonstrations is well above the limits required by the rule and that
continuous monitoring is not needed. When inerts are added
intermittently or process operations change that may lower the NHV, the
proposed standards require re-demonstration with a new 14-day sampling
effort. The new demonstration would consider the variability associated
with these operations and determine a reasonable lower-range value to
use in the compliance assessments. As such, we propose to find that the
sampling requirements, with the revisions proposed, are robust and
sufficient for the demonstration and that continuous monitoring is not
needed when the demonstration shows the NHV value of the gas stream
being controlled is sufficiently high, when considering the range of
vent gas and assist gas flow rates, to meet the required standards.
The EPA is also requesting comment on the proposed removal of the
associated gas monitoring exemption and the proposed requirement for
continuous measurement or sampling requirements for pressure-assisted
flares and enclosed combustion devices at new and existing sources and
for air- and steam-assisted flares or enclosed combustion devices at
new sources. The EPA is requesting comment on whether there are other
known process or upset condition scenarios which may introduce inert
gases or other low-Btu streams into affected facility vent gas streams,
resulting in NHV values which could be below the thresholds in the
March 2024 final rule for flares and enclosed combustion devices
subject to the vent gas NHV requirements of 200 or 300 Btu/scf and
necessitating a determination of the NHV of the combined stream(s). The
EPA also is requesting comment on how the EPA can determine (e.g., the
presence or absence of certain process equipment or piping
configurations) that these scenarios are present at an affected
facility and, therefore, require NHV continuous monitoring or the use
of the sampling option to demonstrate that the mixed gas stream has
sufficient NHV content to afford proper combustion efficiencies.
b. Sampling Location and Duration for the Alternative Performance Test
The EPA is reconsidering the requirements in the March 2024 final
rule regarding the sampling duration for the alternative performance
test (sampling demonstration) option for the NHV compliance
demonstration, and is proposing to allow for shorter sampling times
when it is technically infeasible to collect a grab sample for a
minimum of one hour. While the March 2024 final rule included
provisions for sampling periods of longer than 14 days (where needed)
to collect a total of 28 samples, and the general provisions in 40 CFR
60.8(b)(5) also allow for ``shorter sampling times and smaller sample
volumes when necessitated by process variables or other factors,'' the
EPA finds compelling the petitioners' arguments and newly presented
supporting information regarding the potential instances of
intermittent flow of gas streams, which makes sampling for one hour
technically infeasible in those cases (e.g., intermittent flow from
sources with low pressure). As such, the EPA finds it appropriate to
propose additional flexibility in the final rule to fully address these
intermittent flow situations. Therefore, the EPA is proposing that
sampling must be conducted for a minimum of one hour, when technically
feasible. When it is not technically feasible to collect the sample for
a minimum of one hour, the owner or operator should collect the sample
for as long as possible, up to one hour. For samples taken during low
or intermittent flow events, the collection time and the reason for not
obtaining a full one-hour sample must be documented and reported with
the NHV sampling results. We request comment on the actual duration of
flow that is achievable in practice for those cases where sampling for
one hour is technically infeasible on low pressure and intermittent gas
streams, and why a one hour sample would be technically infeasible for
those cases.
Regarding the location for sampling, the EPA notes that, according
to the March 2024 final rule, the sample must be taken of the inlet gas
to the control device, but the gas need not be taken directly at the
inlet of the control device. We consider a sample within the control
device header system in a location after all vent streams sources have
been added to the control device header as an inlet gas sample. While
the EPA recognizes petitioners' concerns with installing sampling ports
or ``taps'' on these source types, the March 2024 final rule does not
specify a physical location where the sampling must occur. The EPA
therefore does not believe it is necessary to specify that sampling may
occur at another ``representative'' location or specify such
``representative'' locations. The EPA also notes that the General
Provisions in 40 CFR part 60 include procedures for alternatives to
monitoring, including alternative locations for monitoring, ``when the
owner or operator can demonstrate that installation at alternate
locations will enable accurate and representative measurements'' \43\--
these provisions already address site-specific issues with conducting
the alternative performance test (sampling demonstration) option.
Accordingly, the EPA is proposing not to change the current provisions
in the March 2024 final rule regarding sampling location for the NHV
grab sample option.
---------------------------------------------------------------------------
\43\ Per 40 CFR 60.5417b(d), requests for approval to monitor
different monitoring parameters can be made under the Alternative
Monitoring Plan (AMP) provisions in 40 CFR 60.13(i).
---------------------------------------------------------------------------
c. Methodologies for Compositional Analysis of the Gas Stream
The EPA is reconsidering the requirements in the March 2024 final
rule which limited the test method available for determining the
compositional analysis of the gas stream to ASTM-D1945-14 (R2019). The
EPA recognizes that other rules in which vent gases are analyzed, such
as 40 CFR part 63 subpart CC (Refinery MACT) and the Greenhouse Gas
Reporting Program (GHGRP) rule allow the use of other test methods. The
EPA is soliciting comment to expand the use of similar consensus-based
standards (e.g., GPA 2166 and GPA 2261) to consider if these additional
available methods would alleviate petitioners' concerns that ASTM-D1945
is not widely available and that testing laboratories do not have the
capacity currently to enable its use.
Regarding the units in which NHV is determined as prescribed in the
March 2024 final rule, the EPA does not disallow the use of measurement
methods that determine concentrations in terms of weight fractions, but
the weight fractions must be converted to volume fractions because the
calculations referenced therein from part 63 use Btu/scf (not Btu/lb).
Therefore, the EPA is not proposing to change the units in the March
2024 final rule, but rather proposing to clarify that NHV for
individual components must be determined in units of Btu/scf consistent
with the existing specification using published values of the component
NHV per mole at 25 [deg]C and 1 atmosphere and using 20 [deg]C as the
standard temperature for determining the volume corresponding to one
mole of vent gas. We noted that SPL reported
[[Page 3749]]
the NHV of common constituents in vent gas streams at the incorrect
temperature. Therefore, we are proposing to clarify that the standard
temperature for 40 CFR part 60 (at 40 CFR 60.18(f)(3)) is 20 [deg]C and
that the NHV values must be determined at this standard temperature.
These clarifications are proposed to ensure the NHV determinations are
conducted consistently and accurately. The EPA is requesting comment on
the proposed clarifications of the NHV units of measure and calculation
procedures.
We are also proposing to clarify that Tedlar bags may be used to
satisfy the grab sampling requirements, provided that the Tedlar bag
qualifies as an ``evacuated container'' as prescribed by section
8.2.1.1 of EPA Method 18. We request comment on the need to clarify
that Tedlar bags can be used and the limitation proposed on when Tedlar
bags can be used.
d. NHVcz and NHVdil for Air- and Steam-Assisted
Flares and Enclosed Combustion Devices at Existing and New Sources
The EPA is proposing to retain the NHVcz and
NHVdil requirements for air- and steam assisted flares for
sources subject to NSPS subpart OOOOb because, as noted in the November
2021 Proposal (86 FR 63246; November 15, 2021), the EPA had received
some data indicating air-assisted and steam-assisted flares have been
found operating outside of the conditions necessary to achieve at least
98 percent control efficiency on a continuous basis. We disagree with
petitioners that these NHV-related parameters are not appropriate for
assisted flares in the oil and gas industry because we had evidence of
poor-performing assisted flares in the oil and gas industry. The EPA
therefore proposes to conclude (as in the March 2024 final rule) that
sufficient evidence exists demonstrating poor destruction efficiencies
due to over-assisting a flare or enclosed combustion device, such that
NHV compliance demonstrations are necessary to show that these
particular control devices are meeting the requisite efficiency. The
EPA requests comment on the proposed retention of the NHVcz
and NHVdil provisions for new sources. The EPA is also
requesting comment on whether the NHVdil parameter is
appropriate for enclosed combustion devices with perimeter assist air
and the appropriate effective diameter to use in the calculation of
NHVdil, if it is retained, particularly for devices with
multiple burner tips within the enclosed combustion device.
Regarding petitioner GPA's statement that 40 CFR
60.5417b(d)(8)(iii)(H) appears to not allow alternative test methods to
continuously monitor NHVcz and NHVdil, we note
that the provisions at 40 CFR 60.5417b(d)(8)(iii) are specific to the
14-day alternative performance test (sampling demonstration) option and
do not apply to continuous monitoring. We did not include provisions
for a 14-day demonstration using continuous monitoring of
NHVcz and NHVdil because assist rates could be
changed and alter the control device's performance. Continuous
monitoring using alternative test methods is expressly provided for in
40 CFR 60.5412b(d) and 60.5415b(f)(1)(xi). Additionally, we propose to
clarify in 40 CFR 60.5417b(d)(8)(vi) that continuous monitoring of
NHVcz and, if applicable, NHVdil using an
approved alternative method as provided under 40 CFR 60.5412b(d)(1)(i)
and (ii) is allowed and that, when using this alternative test method,
you are not required to monitor NHV of the vent gas as specified in
paragraph (d)(8)(ii) of this section or monitor flow rates as specified
in paragraph (d)(8)(vi) of this section provided you can demonstrate
that the maximum flow rate to the flare cannot cause the flare tip
velocity to exceed 18.3 meter/second (60 feet/second). The EPA requests
comment on the proposed clarifications when using the alternative test
method to demonstrate continuous compliance and requests comment on
whether and how such monitoring could be used as part of the 14-day
sampling demonstration.
With respect to the monitoring requirements for NHVcz
and NHVdil for air- and steam-assisted flares at new
sources, the EPA acknowledges the petitioners' concerns but is not
proposing significant changes to this requirement for new sources
subject to NSPS subpart OOOOb. However, in reviewing these requirements
we note that the requirements in 40 CFR 60.1547b(d)(8)(vi) reference
NHV determinations using the lowest NHV result of the sampling
demonstration in 40 CFR 60.1547b(d)(8)(iii), but 40 CFR
60.1547b(d)(8)(iii) did not have provisions for steam-assisted nor for
certain air-assisted flares or enclosed combustion devices. Therefore,
we are proposing to clarify that 40 CFR 60.1547b(d)(8)(iii) can be used
for any steam- or air-assisted flare or enclosed combustion device, and
that the effective vent gas NHV to allow the use of the demonstration
is 300 Btu/scf when using continuous 14-day sampling or 360 Btu/scf
when using the 14-day grab sampling approach. This revision in 40 CFR
60.1547b(d)(8)(iii) is necessary considering the calculation provision
in 40 CFR 60.1547b(d)(8)(vi) and corrects an unintended error in the
March 2024 final rule. The EPA requests comment on the use of the
proposed use of the 14-day sampling demonstration in 40 CFR
60.1547b(d)(8)(iii) for air- and steam-assisted flares, particularly
those at new sources subject to NHVcz and NHVdil
requirements.
With the alternative sampling provisions being proposed in 40 CFR
60.5417b(d)(8)(iii) and the assessments outlined in 40 CFR
60.5417b(d)(8)(iv), we expect few facilities will have to install
continuous monitoring systems. Since monitoring is necessary to ensure
proper operation of these flares at new sources, and considering the
monitoring options provided by the proposed revisions will afford
sources additional flexibility when compared to the March 2024 final
rule, we are retaining the NHVcz and NHVdil
requirements in NSPS subpart OOOOb.
A provision to conduct monitoring for NHVcz and
NHVdil at existing sources was included in the March 2024
final rule subpart OOOOc model rule in error. The EPA did not conduct
Refinery MACT cost level monitoring for existing sources, and stated in
the preamble to the March 2024 final rule that monitoring of
NHVcz and NHVdil was not recommended as part of
the Emission Guidelines for existing sources due to concerns about
retrofitting existing flares to meet the requirements.\44\ The EPA is
proposing to correct this inadvertent error by removing the language in
the model rule to conduct monitoring of NHVcz and
NHVdil at existing sources and specifying the model rule for
these control systems is an NHV of 300 Btu/scf in the vent gas. The EPA
is requesting comment on the appropriateness of using an NHV of 300
Btu/scf in the vent gas for air- and steam-assisted flares or enclosed
combustion devices at existing sources for demonstrating compliance
with the combustion efficiency requirements for these control devices.
---------------------------------------------------------------------------
\44\ See 89 FR 16895 and 16967.
---------------------------------------------------------------------------
e. Miscellaneous Other Changes
In addition to the proposed changes described above, the EPA is
proposing to clarify that for the purposes of determining the hourly
average of the NHV for continuously sampled (i.e., sampled continuously
for 14 consecutive days) inlet streams, the hourly average shall be
determined on a block (and not a rolling) average. The
[[Page 3750]]
EPA is proposing this clarifying edit to ensure that all owners and
operators are using the same averaging timeframe and it is not left up
to interpretation as to whether the average should be a block average
or a rolling average. Block averages are required for other averaging
time periods in the March 2024 final rule and we consider this change
to be warranted for consistency and clarity. The EPA also is proposing
to clarify that the 14-day period for the continuous monitoring option
shall be consecutive operating days. However, for manual grab sampling,
the EPA is proposing to allow for breaks for weekends and holidays
which may occur during the 14-day representative grab sampling period,
such that these do not have to be consecutive. Consecutive operating
days are reasonable for continuous monitoring because these systems are
present continuously. However, manual grab sample collection requires
someone to be present at the site to collect samples each day, which,
if required to be done on consecutive days, would require collection on
weekends and potentially on holidays. The final requirements of the
March 2024 final rule already allows for sampling beyond the 14 days if
28 samples cannot be collected during that time frame. Allowing
additional flexibility for non-consecutive operating day sampling can
lengthen the time needed to collect samples and delay the conclusion of
the NHV determination, but it does not reduce the number of samples
required nor the representativeness of those samples. As such, we
consider it reasonable to provide some flexibility in the grab sampling
approach to allow twice daily sampling to determine the average NHV of
the gas stream for 14 operating days, with no sampling day to be spaced
more than 3 operating days apart from the previous sampling day.
Finally, the EPA is proposing to allow 60 days for conducting the
continuous NHV monitoring required by one of the options in 40 CFR
60.5417b(d)(8)(ii)(A) through (D) if the results of the periodic (3
samples every 5 years) sampling indicate that the NHV is less than 1.2
times the applicable threshold NHV level in the rule. The EPA considers
it necessary to specify a timeframe to install and operate the required
continuous monitors to provide owners and operators with regulatory
certainty for when this must occur. We consider 60 days to be an
expedited time schedule for the installation of continuous monitoring
systems, but we consider it a reasonable timeframe for installing
necessary grab sampling systems to automatically collect samples at
least once every 8 hours as provided in 40 CFR 60.5417b(d)(8)(ii)(D).
Facilities would be required to collect grab samples every 8 hours
until such time a continuous monitor can be installed, and installation
of such a system requires more than 60 days. We request comment on the
proposed 60-day compliance provision when a 5-year sampling event
indicates the vent stream is not sufficiently above the required NHV.
The EPA also is proposing a similar change to address compliance
timing pending the re-evaluation that must occur after a process change
that potentially reduces the NHV of the gas sent to an enclosed
combustion device or flare. For the same reasons as stated above (i.e.,
for continuous monitoring which must occur after the results of
periodic monitoring indicate the vent stream is not sufficiently above
the required NHV), the EPA is proposing that continuous monitoring
should commence within 60 days after the re-evaluation indicates that
the inlet gas stream does not meet the limits. The EPA also is
proposing to clarify, for both periodic testing and re-evaluations
which occur after a process change, that if the results of the grab
sampling indicate that the vent stream is not sufficiently above the
required NHV, continuous monitoring using a calorimeter, GC, MS, or
continuous grab sampling (i.e., once every 8 hours) sampling must
commence within the specified timeframe.
Finally, the EPA is proposing revisions to the provisions in 40 CFR
60.1547b(d)(8)(v), which include one-time assessments to be used in
lieu of installing vent gas flow monitors and, in the case of assisted
flares, assist gas flow monitors if certain provisions are met. While
we finalized provisions to unassisted flares to conduct an initial
determination to ensure the flare tip velocity is not exceeded under
worst-case flow provisions, this requirement was not included in the
March 2024 final rule for air-assisted flares, even though the velocity
limits apply. Therefore, we are proposing to add this maximum velocity
assessment to the existing provisions in 40 CFR 60.1547b(d)(8)(v)(D)
and (E) for air-assisted flares. This provision is not applicable to
enclosed combustion devices. In reviewing these provisions, we also
noted that there was no corresponding provision for steam-assisted
flares or enclosed combustion devices. This was an oversight in the
March 2024 final rule and we are proposing new provisions at 40 CFR
60.1547b(d)(8)(v)(F) similar to those for air-assisted devices that are
specific to steam-assisted flares or enclosed combustion devices. These
revisions are not needed in NSPS subpart OOOOc because these provisions
are specific to evaluations for flares complying with an
NHVcz or NHVdil parameter. The EPA requests
comment on these proposed provisions to ensure compliance with the
velocity operating limit and whether, for those devices that have
conducted NHV demonstrations, the velocity limit used in the assessment
should be based on the allowable velocity at the lowest NHV result from
the demonstration rather than being based on the default of 18.3
meters/second (60 feet/second).
IV. How do these proposed amendments impact the implementation of EG
OOOOc?
The EPA's proposed amendments discussed in section III (Summary and
Rationale of Proposed Amendments to NSPS OOOOb and EG OOOOc) of this
preamble in response to several petitions for reconsideration of
aspects of the 2024 NSPS and EG final rule would not significantly
impact the implementation of EG OOOOc or the State planning process.
Based on the EPA's reconsideration, the EPA is proposing amendments
that revise two narrow aspects of the EG's model rule: (1) The
associated gas temporary flaring provisions for certain situations and
(2) the NHV value continuous monitoring and alternative performance
test (sampling demonstration) provisions for certain combustion control
devices. The proposed amendments do not alter in any way the EPA's
identified best system of emission reduction (BSER) in the EG, the
EPA's identified degree of emissions limitation achievable via
application of that BSER, the timeline for State plan submittal, or
compliance timelines finalized under EG OOOOc. Any changes that a State
or Tribe may make to their plan as a result of this proposed action
will be minor such that the State or Tribe should be able to make such
changes before their plans are required to be submitted for approval.
As indicated in section I.A (Does this action apply to me?) of this
preamble, the issuance of the CAA section 111(d) final EG does not
impose binding requirements directly on existing sources. The EG
(codified in 40 CFR part 60, subpart OOOOc) applies to States in the
development, submittal, and implementation of State plans to establish
performance standards to reduce emissions of GHGs from designated
facilities that are existing sources on or before December 6, 2022.
Further, under the TAR, eligible Tribes
[[Page 3751]]
may seek approval to implement a plan under CAA section 111(d) in a
manner similar to a State, and Tribes are authorized under the TAR to
develop and implement their own air quality programs, or portions
thereof, under the CAA.
V. Summary of Cost, Environmental, and Economic Impacts
The proposed NSPS OOOOb and EG OOOOc discrete compliance
requirement revisions included in this action and discussed in section
III (Summary and Rationale of Proposed Amendments to NSPS OOOOb and EG
OOOOc) of this preamble do not alter the substantive requirements of
the final rule. The economic impacts and a qualitative discussion of
the environmental impacts are presented in the memorandum titled
Economic Impact Analysis for 2024 NSPS & EG Reconsideration. There are
no other quantifiable environmental (e.g., air quality, water, waste),
energy, or benefits beyond those already presented in accompanying
Regulatory Impact Analysis (RIA) for the March 8, 2024, Standards of
Performance for New, Reconstructed, and Modified Sources and Emissions
Guidelines for Existing Sources: Oil and Natural Gas Sector Climate
Review final rule (89 FR 16820). As such, a new environmental justice
(EJ) analysis was not conducted for this action.
VI. Statutory and Executive Order Reviews
Additional information about these statutes and Executive orders
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 14094: Modernizing Regulatory Review
This action is a ``significant regulatory action'' as defined in
Executive Order 12866, as amended by Executive Order 14094.
Accordingly, the EPA submitted this action to the Office of Management
and Budget (OMB) for Executive Order 12866 review. Documentation of any
changes made in response to the Executive Order 12866 review is
available in the docket for this action (see memorandum titled Economic
Impact Analysis for 2024 NSPS & EG Reconsideration).
B. Paperwork Reduction Act (PRA)
The information collection activities for NSPS OOOOb and EG OOOOc
were previously approved by OMB under the PRA as of June 28, 2024.
The EPA has revised the approved information collection request
(ICR) to include small changes to incorporate EPA's proposed
recordkeeping and reporting to indicate whether the flare or enclosed
combustion device receives inert gases or other streams which may lower
the NHV of the combined stream as proposed in section III.B of this
preamble. The EPA estimates an average of 48 respondents will be
affected by this proposed requirement over the three-year period (2023-
2025). The average annual burden for the recordkeeping and reporting
requirements for these owners and operators is estimated at 83 person-
hours, with an average annual cost of $4,374 over the three-year
period.
The EPA also revised the approved ICR to include burden estimates
for the maintenance of records that EPA is soliciting comment on.
Specifically, the EPA includes burden estimates in the revised ICR for
the records and annual reporting that would be required if EPA were to
allow for the use of the associated gas extended flaring allowance
under ``exigent circumstances'' as specified in section III.A of this
preamble. The incremental increase in burden that would be associated
with these recordkeeping and reporting requirements relative to the
baseline is estimated at 2 hours per event annually over the three-year
period (2024-2026) at an average annual cost of $120 per flaring event
over the three-year period. The occurrence of flaring that could
potentially be claimed due to ``exigent circumstances'' is unknown.
However, we expect that a maximum of 16 percent of flaring events could
potentially require an owner or operator to need to extend flaring
beyond 48 hours due to ``exigent circumstances''. The burden associated
with the two proposed reconsideration items under this action minimally
affect the ICR burden estimated for compliance with EG OOOOc. The
annual burden for this proposed additional collection of information
for the States would be less than 1 percent.
The approved ICR document that the EPA prepared was assigned OMB
Control No. 2060-0721 and EPA ICR No. 2523.07. You can find a copy of
the previously submitted ICR in Docket EPA-HQ-OAR-2021-0317. The
revised ICR document that the EPA prepared for this reconsideration
proposal has been assigned OMB Control No. 2060-0721 and EPA ICR No.
2523.08. You can find a copy of the revised ICR in Docket EPA-HQ-OAR-
2024-0358.
C. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. In
making this determination, the EPA concludes that the impact of concern
for this rule is any significant adverse economic impact on small
entities and that the Agency is certifying that this rule will not have
a significant economic impact on a substantial number of small entities
because the rule has reduced net regulatory burden on the small
entities subject to the rule. This action addresses two discrete
compliance requirement aspects of NSPS OOOOb and the model rules within
EG OOOOc based on petitions for reconsideration received on the March
2024 final rule requirements, providing additional flexibilities to
entities subject to the NSPS requirements and to the model rules within
EG OOOOc. We have therefore concluded that this action will have
reduced net regulatory burden for all directly regulated small
entities. For further details, see the document, Economic Impact
Analysis for 2024 NSPS & EG Reconsideration, in the docket.
D. Unfunded Mandates Reform Act (UMRA)
This action does not contain an unfunded mandate of $100 million or
more as described in UMRA, 2 U.S.C. 1531-1538, and does not
significantly or uniquely affect small governments. This action imposes
no enforceable duty on any State, local or Tribal governments or the
private sector. This action addresses two discrete compliance
requirement aspects of NSPS OOOOb and the model rules within EG OOOOc
based on petitions for reconsideration received on the March 2024 final
rule requirements.
E. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government. However,
the EPA recognizes that States will have a substantial interest in this
action and any future revisions to associated requirements. This action
addresses two discrete compliance requirement aspects of NSPS OOOOb and
the model rules within EG OOOOc based on petitions for reconsideration
received on the March 2024 final rule requirements.
[[Page 3752]]
F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This action does not have Tribal implications as specified in
Executive Order 13175. This action addresses two discrete compliance
requirement aspects of NSPS OOOOb and the model rules within EG OOOOc
based on petitions for reconsideration received on the March 2024 final
rule requirements. Thus, Executive Order 13175 does not apply to this
action.
G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive Order. The EPA believes that it is not
practicable to assess whether an environmental health risk or safety
risk affecting children may exist prior to this action. This action
addresses two discrete compliance requirement aspects of NSPS OOOOb and
the model rules within EG OOOOc based on petitions for reconsideration
received on the March 2024 final rule requirements and does not result
in any changes to the BSER of NSPS OOOOb or EG OOOOc. The EPA believes
that the EPA's Policy on Children's Health also does not apply.
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
This action is not a ``significant energy action'' because it is
not likely to have a significant adverse effect on the supply,
distribution or use of energy. Further, we have concluded that this
action is not likely to have any adverse energy effects because this
action addresses two discrete compliance requirement aspects of NSPS
OOOOb and the model rules within EG OOOOc based on petitions for
reconsideration received on the March 2024 final rule requirements and
does not result in any changes to the BSER of NSPS OOOOb or EG OOOOc.
I. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR
Part 51
This action does not involve any new technical standards.
Therefore, the NTTAA does not apply.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations and
Executive Order 14096: Revitalizing Our Nation's Commitment to
Environmental Justice for All
The EPA believes that it is not practicable to assess whether the
human health or environmental conditions that exist prior to this
action result in disproportionate and adverse effects on communities
with EJ concerns. This action addresses two discrete compliance
requirement aspects of NSPS OOOOb and the model rules within EG OOOOc
based on petitions for reconsideration received on the March 2024 final
rule requirements and does not result in any changes to the BSER of
NSPS OOOOb or EG OOOOc. The EPA lacks specific and representative data
on the frequency of temporary or emergency flaring, the number of
sources flaring, or the length of time temporary flaring occurs. This
data limitation prevents the EPA from estimating the impacts of an
extension of allowed flaring. The March 2024 final rule describes how
the rule will result in reductions in VOCs, which are an important
precursor contributing to ground-level ozone formation in many regions
of the country and reduce methane pollution that contributes to climate
change, which itself has substantial and adverse impacts on EJ
communities.\45\ The information supporting this Executive Order review
is contained in the docket for this action (see memorandum titled
Economic Impact Analysis for 2024 NSPS & EG Reconsideration).
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\45\ 89 FR 17031.
Michael S. Regan,
Administrator.
[FR Doc. 2024-31227 Filed 1-14-25; 8:45 am]
BILLING CODE 6560-50-P