[Federal Register Volume 88, Number 86 (Thursday, May 4, 2023)]
[Proposed Rules]
[Pages 28918-28984]
[FR Doc No: 2023-08732]

Vol. 88

Thursday,

No. 86

May 4, 2023

Part V

Environmental Protection Agency

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40 CFR Parts 52, 78, and 97

Revision and Promulgation of Air Quality Implementation Plans; Texas;
Regional Haze Federal Implementation Plan; Disapproval and Need for
Error Correction; Denial of Reconsideration of Provisions Governing
Alternative to Source-Specific Best Available Retrofit Technology
(BART) Determinations; Proposed Rule

Federal Register / Vol. 88, No. 86 / Thursday, May 4, 2023 / Proposed
Rules

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 ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52, 78, and 97

[EPA-R06-OAR-2016-0611; EPA-HQ-OAR-2016-0598; FRL-9771-01-R6]

Revision and Promulgation of Air Quality Implementation Plans;
Texas; Regional Haze Federal Implementation Plan; Disapproval and Need
for Error Correction; Denial of Reconsideration of Provisions Governing
Alternative to Source-Specific Best Available Retrofit Technology
(BART) Determinations

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: Pursuant to the Federal Clean Air Act (CAA or Act), the
Environmental Protection Agency (EPA) is proposing to withdraw the
existing Texas Sulfur Dioxide (SO2) Trading Program
provisions, which constitute the Federal implementation plan (FIP) the
EPA previously promulgated to address SO2 Best Available
Retrofit Technology (BART) requirements for EGUs in Texas that are not
adequately satisfied by the Texas Regional Haze State implementation
plan (SIP). In its place, the EPA proposes a FIP that establishes
SO2 limits on 12 Electric Generating Units (EGUs) located at
six Texas facilities to fulfill requirements of the Regional Haze Rule
for the installation and operation of BART for SO2. Based on
these proposed changes, we also propose to affirm the continued
validity of participation in the Cross-State Air Pollution Rule (CSAPR)
trading programs as a BART alternative. Therefore, the EPA is proposing
to deny a petition for reconsideration of our 2017 determination that
States that are participating in CSAPR can continue to rely on CSAPR
participation as a BART alternative. Finally, we are proposing to find
that our prior approval of the portion of the Texas Regional Haze SIP
that addresses the BART requirement for EGUs for Particulate Matter
(PM) was made in error and are proposing to correct that error by
proposing to disapprove that portion of the Texas Regional Haze SIP
through our authority under the CAA section 110(k)(6), and, as part of
a FIP, we are proposing PM BART limits for 12 EGUs located at six Texas
facilities.

DATES:
    Comments: Comments must be received on or before July 3, 2023.
    Virtual Public Hearing: The EPA will hold a virtual public hearing
to solicit comments on May 19, 2023. The last day to pre-register to
speak at the hearing will be on May 17, 2023. On May 18, 2023, the EPA
will post a general agenda for the hearing that will list pre-
registered speakers in approximate order at https://www.epa.gov/tx/texas-regional-haze-best-available-retrofit-technology-federal-implementation-plan-and-cross. If you require the services of a
translator or a special accommodation such as audio description/closed
captioning, please pre-register for the hearing and describe your needs
by May 11, 2023.
    For more information on the virtual public hearing, see
SUPPLEMENTARY INFORMATION.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R06-
OAR-2016-0611 to the Federal eRulemaking Portal: https://www.regulations.gov/ (our preferred method). For additional submission
methods, please contact the person identified in the FOR FURTHER
INFORMATION CONTACT section.
    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.
    Docket: The docket for this action is available electronically at
https://www.regulations.gov. Some information in the docket may not be
publicly available via the online docket due to docket file size
restrictions, such as certain modeling files, or content (e.g., CBI).
To request a copy of the modeling files, please send a request via
email to [email protected]">R6[email protected]. For questions about a
document in the docket please contact individual listed in the FOR
FURTHER INFORMATION CONTACT section.
    CBI: Do not submit information containing CBI to the EPA through
https://www.regulations.gov. To submit information claimed as CBI,
please contact the individual listed in the FOR FURTHER INFORMATION
CONTACT section. Clearly mark the part or all of the information that
you claim to be CBI. In addition to one complete version of the
comments that includes information claimed as CBI, you must submit a
copy of the comments that does not contain the information claimed as
CBI directly to the public docket through the procedures outlined in
Instructions earlier. 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. For the full EPA public comment policy, information about
CBI or multimedia submissions, and general guidance on making effective
comments, please visit https://www2.epa.gov/dockets/commenting-epa-dockets.
    To pre-register to attend or speak at the virtual public hearing,
please use the online registration form available at https://www.epa.gov/tx/texas-regional-haze-best-available-retrofit-technology-federal-implementation-plan-and-cross or contact us via email at
[email protected]. For more information on the virtual
public hearing, see SUPPLEMENTARY INFORMATION.

FOR FURTHER INFORMATION CONTACT: Michael Feldman, Air and Radiation
Division, SO2 and Regional Haze Section (ARSH),
Environmental Protection Agency, 1201 Elm St., Suite 500 Dallas, TX
75270; telephone number:<PHONE_NUMBER>; or via email:
[email protected].

SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' or ``our'' is used, we mean the EPA.
    There are two dockets supporting this action, EPA-R06-OAR-2016-0611
and EPA-HQ-OAR- EPA-HQ-OAR-2016-0598. Docket No. EPA-R06-OAR-2016-0611
contains information specific to BART requirements for Texas, including
this notice of proposed rulemaking and prior rulemakings related to
Texas BART, previous submittals from the State, and the Technical
Support Documents for this action. Docket No. EPA-HQ-OAR-2016-0598
contains previous actions and information related to CSAPR as a BART
alternative. All comments regarding this proposed action should be made
in Docket No. EPA-R06-OAR-2016-0611. For additional submission methods,
please email [email protected].

Virtual Public Hearing

    The EPA is holding a virtual public hearing to provide interested
parties the opportunity to present data, views, or arguments concerning
the proposal. The EPA will hold a virtual public hearing to solicit
comments on May 19, 2023. The hearing will convene in two sessions.
Session 1 will convene at 1 p.m. Central Time (CT) and will conclude at
3 p.m. CT, or 15 minutes after the last pre-registered presenter in
attendance has presented if there are no additional presenters. Session
2 will convene at 4 p.m. Central Time (CT) and will conclude at 7 p.m.
CT, or 15 minutes after the last pre-registered presenter in attendance
has presented if

there are no additional presenters. The EPA will announce further
details, including information on how to register for the virtual
public hearing, on the virtual public hearing website at https://www.epa.gov/tx/texas-regional-haze-best-available-retrofit-technology-federal-implementation-plan-and-cross. The EPA will begin pre-
registering speakers and attendees for the hearing upon publication of
this document in the Federal Register. To pre-register to attend or
speak at the virtual public hearing, please use the online registration
form available at https://www.epa.gov/tx/texas-regional-haze-best-available-retrofit-technology-federal-implementation-plan-and-cross or
contact us via email at [email protected]. The last day to
pre-register to speak at the hearing will be on May 17, 2023. On May
18, 2023, the EPA will post a general agenda for the hearing that will
list pre-registered speakers in approximate order at https://www.epa.gov/tx/texas-regional-haze-best-available-retrofit-technology-federal-implementation-plan-and-cross. Additionally, requests to speak
will be taken on the day of the hearing as time allows.
    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
hearing to run either ahead of schedule or behind schedule. Each
commenter will have approximately 3 to 5 minutes to provide oral
testimony. The EPA encourages commenters to provide the EPA with a copy
of their oral testimony electronically by including it in the
registration form or emailing it to [email protected]. 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 comments and supporting
information presented at the virtual public hearing. A transcript of
the virtual public hearing, as well as copies of oral presentations
submitted to the EPA, will be included in the docket for this action.
    The EPA is asking all hearing attendees to pre-register, even those
who do not intend to speak. The EPA will send information on how to
join the public hearing to pre-registered attendees and speakers.
    Please note that any updates made to any aspect of the hearing will
be posted online at https://www.epa.gov/tx/texas-regional-haze-best-available-retrofit-technology-federal-implementation-plan-and-cross.
While the EPA expects the hearing to go forward as set forth above,
please monitor our website or contact us via email at
[email protected] to determine if there are any updates.
The EPA does not intend to publish a document in the Federal Register
announcing updates.
    If you require the services of a translator or a special
accommodation such as audio description/closed captioning, please pre-
register for the hearing and describe your needs by May 11, 2023. The
EPA may not be able to arrange accommodations without advance notice.

Table of Contents

I. Executive Summary
II. Background
    A. Regional Haze
    B. BART
    C. Previous Actions Related to Texas BART and ``CSAPR Better-
Than-BART''
    D. Consultation With Federal Land Managers (FLMs)
III. Overview of Proposed Action
IV. Withdrawal of the Texas SO2 Trading Program as a BART
Alternative for SO2
    A. Legal Authority To Withdraw the Texas SO2 Trading
Program
    B. Basis for Withdrawing the Texas SO2 Trading
Program
V. CSAPR Participation as a BART Alternative
    A. Introduction
    B. Background
    C. Summary of the 2020 Petition for Reconsideration and
Associated Litigation
    D. Criteria for Granting a Mandatory Petition for
Reconsideration
    E. The EPA's Evaluation of the Petition for Reconsideration
VI. The EPA's Authority To Promulgate a FIP Addressing
SO2 and PM BART
    A. CAA Authority To Promulgate a FIP for SO2 BART
    B. Error Correction and CAA Authority To Promulgate a FIP--PM
BART
VII. BART Analysis for SO2 and PM
    A. Identification of Sources Subject to BART
    B. BART Five Factor Analysis
VIII. Weighing of the Five BART Factors and Proposed BART
Determinations
    A. SO2 BART for Coal-Fired Units With no
SO2 Controls
    B. SO2 BART for Coal-Fired Units With Existing
Scrubbers
    C. PM BART
IX. Proposed Action
    A. Regional Haze
    B. CSAPR Better-Than-BART
X. Environmental Justice Considerations
XI. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Overview
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    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 That Significantly Affect
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
    K. Determinations Under CAA Section 307(b)(1) and (d)

I. Executive Summary

    The CAA's visibility protection program was created in response to
a national goal set by Congress in 1977 to remedy and prevent
visibility impairment in certain national parks, such as Grand Canyon
National Park, and national wilderness areas, such as the Okefenokee
National Wildlife Refuge. Vistas in these areas are often obscured by
visibility impairment such as regional haze, which is caused by
emissions from numerous sources located over a wide geographic area.
    In response to this Congressional directive, the EPA promulgated
regulations to address visibility impairment in 1999. These
regulations, which are commonly referred to as the Regional Haze Rule,
established an iterative process for achieving Congress's national goal
by providing for multiple, approximately 10-year ``planning periods''
in which State air agencies must submit to EPA plans that address
sources of visibility-impairing pollution in their States. The first
State plans were due in 2007 for the planning period that ended in
2018. The second State plans were due in 2021 for the period that ends
in 2028. This proposal focuses on obligations from the first planning
period of the regional haze program.
    A central element of these first planning period State plans was
the requirement for certain older stationary sources to install the
Best Available Retrofit Technology (BART) for the purpose of making
reasonable progress towards Congress's national goal of eliminating
visibility impairment within our nation's most treasured lands. The
Regional Haze Rule provided two approaches a State could take to
fulfill its BART obligations: (1) conduct source-by-source evaluations
for covered sources, or (2) implement an alternative program, such as
an emissions trading program, that achieves greater reasonable progress
than source-by-source BART.

    One such BART alternative that 19 States have relied on for over a
decade to fulfill some or all of their BART obligations with respect to
visibility-impairing pollution from power plants is participation in
the EPA's Cross-State Air Pollution Rule (CSAPR), an emissions trading
program that was promulgated in 2011. Changes to the CSAPR program over
the years, particularly with respect to the status of the State of
Texas, have required the EPA to reexamine on several occasions whether
the program continues to achieve greater reasonable progress than
source-by-source BART for participating States. Most recently, after
removing Texas from certain aspects of the CSAPR program, the EPA
reaffirmed the viability of the CSAPR program as a BART alternative in
2017 and then again in 2020 when the EPA denied a petition for
reconsideration of the 2017 reaffirmation.
    Texas submitted its first State plan to address regional haze in
2009, relying at that time on the now-defunct predecessor program to
CSAPR to satisfy the BART requirement for its power plants.\1\ The EPA
disapproved this portion of Texas's plan in 2012. Texas is home to
numerous power plants, many of which operate without modern pollution
controls. As a result, several of these plants are among the highest
emitters of visibility-impairing pollutants, such as sulfur dioxide
(SO2), in the nation. These emissions cause or contribute to
visibility impairment in such iconic places as Big Bend National Park
and Guadalupe Mountains National Park in Texas, Salt Creek Wilderness
Area in New Mexico, Caney Creek Wilderness Area in Arkansas, and
Wichita Mountains Wilderness Area in Oklahoma. In 2017, the EPA
proposed to address the gap in Texas's plan by, among other things,
requiring source-by-source BART controls for SO2 emissions
from covered sources that would have significantly reduced these
emissions. The EPA never finalized this proposal, however. Instead, in
2017 (and again in 2020), the EPA promulgated an intrastate trading
program to govern SO2 emissions from Texas power plants,
based on a finding that the program would achieve greater reasonable
progress than source-by-source BART even though the program would allow
for increases in SO2 emissions (and thus increased
visibility impairment) instead of emission reductions.
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    \1\ https://www.tceq.texas.gov/airquality/sip/bart/haze_sip.html.
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    This proposal seeks to address both the BART requirements for
Texas's power plants and an outstanding petition that once again calls
into question the continued viability of the CSAPAR program as a BART
alternative for participating States due to the status of Texas, and
the complicated interactions between these two regulatory regimes.
Specifically, the EPA is proposing to withdraw the intrastate trading
program on the basis that it does not achieve greater reasonable
progress than source-by-source BART. In its place, the EPA is proposing
to promulgate source-by-source BART emission limits for covered sources
in Texas. If finalized, these emission limits would reduce emissions
from these sources by more than 80,000 tons of SO2
emissions, improving visibility across a wide range of the nation's
most scenic vistas. In addition, the EPA is proposing that these
changes to the Texas plan, if finalized, would allow the EPA to once
again reaffirm that the CSAPR program remains a viable BART alternative
for the 19 participating States. On that basis, the EPA is proposing to
deny the outstanding petition seeking to end these States' longstanding
reliance on the CSAPR program to satisfy their BART obligations for
power plants.

II. Background

A. Regional Haze

    Regional haze is visibility impairment that is produced by a
multitude of sources and activities which are located across a broad
geographic area. These sources and activities emit fine particulate
matter (PM2.5) (e.g., sulfates, nitrates, organic carbon,
elemental carbon, and soil dust) and its precursors (e.g., sulfur
dioxide (SO2), nitrogen oxides (NOX), and, in
some cases, ammonia (NH3) and volatile organic compounds
(VOCs)). Fine particle precursors react in the atmosphere to form
PM2.5, which, in addition to direct sources of PM
2.5, impairs visibility by scattering and absorbing light.
Visibility impairment (i.e., light scattering) reduces the clarity,
color, and visible distance that one can see. PM2.5 can also
cause serious health effects (including premature death, heart attacks,
irregular heartbeat, aggravated asthma, decreased lung function, and
increased respiratory symptoms) and mortality in humans, and
contributes to environmental effects such as acid deposition and
eutrophication.
    In section 169A of the 1977 Amendments to the Clean Air Act (CAA),
Congress created a program for protecting visibility in the nation's
national parks and wilderness areas. This section of the CAA
establishes as a national goal the prevention of any future, and the
remedying of any existing, anthropogenic impairment of visibility in
156 national parks and wilderness areas designated as mandatory Class I
areas.\2\ Congress added section 169B to the CAA in 1990 to address
regional haze issues, and the EPA promulgated the Regional Haze Rule
(RHR), codified at 40 CFR 51.308,\3\ on July 1, 1999.\4\ The RHR
established a requirement to submit a regional haze SIP, which applies
to all 50 States, the District of Columbia, and the Virgin Islands.\5\
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    \2\ Areas designated as mandatory Class I areas consist of
National Parks exceeding 6,000 acres, wilderness areas and national
memorial parks exceeding 5,000 acres, and all international parks
that were in existence on August 7, 1977. 42 U.S.C. 7472(a). In
accordance with section 169A of the CAA, the EPA, in consultation
with the Department of Interior, promulgated a list of 156 areas
where visibility is identified as an important value. 44 FR 69122
(November 30, 1979). The extent of a mandatory Class I area includes
subsequent changes in boundaries, such as park expansions. 42 U.S.C.
7472(a). Although States and Tribes may designate as Class I
additional areas which they consider to have visibility as an
important value, the requirements of the visibility program set
forth in section 169A of the CAA apply only to ``mandatory Class I
Federal areas.'' Each mandatory Class I Federal area is the
responsibility of a ``Federal Land Manager.'' 42 U.S.C. 7602(i).
When we use the term ``Class I area'' in this action, we mean a
``mandatory Class I Federal area.''
    \3\ In addition to the generally applicable regional haze
provisions at 40 CFR 51.308, the EPA also promulgated regulations
specific to addressing regional haze visibility impairment in Class
I areas on the Colorado Plateau at 40 CFR 51.309. The latter
regulations are not relevant here.
    \4\ See 64 FR 35714 (July 1, 1999). On January 10, 2017, the EPA
promulgated revisions to the RHR that apply for the second and
subsequent implementation periods. See 82 FR 3078 (Jan. 10, 2017).
    \5\ 40 CFR 51.300(b).
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    To address regional haze visibility impairment, the RHR established
an iterative planning process that requires States in which Class I
areas are located and States from which emissions may reasonably be
anticipated to cause or contribute to any impairment of visibility in a
Class I area to periodically submit SIP revisions to address regional
haze visibility impairment.\6\ Under the CAA, each SIP submission must
contain ``a long-term (ten to fifteen years) strategy for making
reasonable progress toward meeting the national goal,'' and the initial
round of SIP submissions also had to address the statutory requirement

that certain older, larger sources of visibility-impairing pollutants
install and operate the Best Available Retrofit Technology (BART), as
discussed further in Section II.B.\7\ States' first regional haze SIPs
were due by December 17, 2007, with subsequent SIP submissions
containing revised long-term strategies originally due July 31, 2018,
and every ten years thereafter.\8\
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    \6\ See 42 U.S.C. 7491(b)(2); 40 CFR 51.308(b) and (f); see also
64 FR 35768 (July 1, 1999). The EPA established in the RHR that all
States either have Class I areas within their borders or ``contain
sources whose emissions are reasonably anticipated to contribute to
regional haze in a Class I area;'' therefore, all States must submit
regional haze SIPs. See 64 FR 35721. In addition to each of the 50
States, the EPA also concluded that the Virgin Islands and District
of Columbia contain a Class I area and/or contain sources whose
emissions are reasonably anticipated to contribute regional haze in
a Class I area. See 40 CFR 51.300(b) and (d)(3).
    \7\ See 42 U.S.C. 7491(b)(2)(A); 40 CFR 51.308(d) and (e).
    \8\ See 40 CFR 51.308(b). The 2017 RHR revisions changed the
second period SIP due date from July 31, 2018, to July 31, 2021, and
maintained the existing schedules for the subsequent implementation
periods. See 40 CFR 51.308(f).
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B. BART

    Section 169A of the CAA directs States to evaluate the use of
retrofit controls at certain larger, older stationary sources to
address visibility impacts from these sources, whose emissions are
often uncontrolled or poorly controlled. Specifically, section
169A(b)(2) of the CAA requires States to revise their SIPs to contain
such measures as may be necessary to make reasonable progress towards
the national visibility goal, including a requirement that certain
categories of existing major stationary sources built between 1962 and
1977 procure, install, and operate BART as determined by the State
applying five statutory factors. On July 6, 2005, the EPA published the
Guidelines for BART Determinations Under the Regional Haze Rule at
Appendix Y to 40 CFR part 51 (BART Guidelines) to assist States in the
BART evaluation process. Under the RHR and the BART Guidelines, the
BART evaluation process consists of three steps: (1) An identification
of all BART-eligible sources in the State, (2) an assessment of whether
the BART-eligible sources are subject to BART (based on a determination
that each source or sources may reasonably be anticipated to cause or
contribute to any visibility impairment in a Class I area), and (3) a
determination of an emission limit reflecting BART after applying the
five statutory BART factors.\9\ In applying the BART factors for a
fossil fuel-fired electric generating plant with a total generating
capacity in excess of 750 megawatts, a State must use the approach set
forth in the BART Guidelines.\10\ A State is generally encouraged, but
not required, to follow the BART Guidelines for other types of
sources.\11\
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    \9\ See generally 40 CFR 51.308(e)(1); 40 CFR part 51, Appendix
Y.
    \10\ 42 U.S.C. 7491(b); 40 CFR 51.308(e)(1)(ii)(B).
    \11\ See 40 CFR part 51, Appendix Y. For additional details
regarding the three steps of the BART evaluation process, see, e.g.,
85 FR 47134, 47136-37 (August 4, 2020).
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    States must make source-specific BART determinations for all
``BART-eligible'' sources determined to be subject to BART. However, as
an alternative to making these ``source-specific'' BART determinations,
States may adopt an emissions trading program or other alternative
program for all or a portion of their BART-eligible sources, so long as
the alternative achieves greater reasonable progress towards improving
visibility than BART would for those sources, and the alternative meets
certain other requirements. Several options are available for making
BART-alternative demonstrations, and these are discussed in greater
detail in Section IV.B and Section V.\12\
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    \12\ See generally 40 CFR 51.308(e)(2)-(4).
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    States generally undertook the BART determination process during
the regional haze program's first implementation period. While the BART
requirement is considered a one-time requirement, BART-eligible
sources, including sources found subject to BART and for which a BART
emission limit was established, may need to be re-assessed for
additional controls in future implementation periods under the CAA's
reasonable progress provisions. Thus, the EPA has stated that States
should treat BART-eligible sources the same as other reasonable
progress sources going forward.\13\
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    \13\ See 81 FR 26942, 26947 (May 4, 2016).
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C. Previous Actions Related to Texas BART and ``CSAPR Better-Than-
BART''

    The procedural history leading up to this proposed action is set
forth in detail in this section. On March 31, 2009, Texas submitted a
regional haze SIP (the 2009 Regional Haze SIP) to the EPA that included
reliance on Texas's participation in trading programs under the Clean
Air Interstate Rule (CAIR) as an alternative to BART for SO2
and NOX emissions from Electric Generating Units (EGUs).\14\
This reliance was consistent with the EPA's regulations at the time
that Texas developed its 2009 Regional Haze SIP.\15\ However, at the
time Texas submitted its SIP to the EPA, the D.C. Circuit had remanded
CAIR (without vacatur).\16\ The court left CAIR and our CAIR FIPs in
place in order to ``temporarily preserve the environmental values
covered by CAIR'' until we could, by rulemaking, replace CAIR
consistent with the court's opinion. The EPA promulgated the Cross-
State Air Pollution Rule (CSAPR) to replace CAIR in 2011 \17\ (and
revised it in 2012).\18\ CSAPR established FIP requirements for sources
in a number of States, including Texas, to address the States'
interstate transport obligation under CAA section 110(a)(2)(D)(i)(I).
CSAPR addresses interstate transport of PM2.5 and ozone by
requiring affected EGUs in these States to participate in one or more
of the CSAPR trading programs, which establish emissions budgets that
apply to the EGUs' collective annual emissions of SO2 and
NOX, as well as emissions of NOX during ozone
season.\19\
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    \14\ CAIR required certain States, including Texas, to reduce
emissions of SO2 and NOX that contribute
significantly to downwind nonattainment of the 1997 NAAQS for fine
particulate matter and ozone. See 70 FR 25152 (May 12, 2005).
    \15\ See 70 FR 39104 (July 6, 2005).
    \16\ See North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008),
as modified, 550 F.3d 1176 (D.C. Cir. 2008).
    \17\ Federal Implementation Plans; Interstate Transport of Fine
Particulate Matter and Ozone and Correction of SIP Approvals, 76 FR
48208 (Aug. 8, 2011).
    \18\ CSAPR was amended three times in 2011 and 2012 to add five
States to the seasonal NOX program and to increase
certain State budgets. 76 FR 80760 (December 27, 2011); 77 FR 10324
(February 21, 2012); 77 FR 34830 (June 12, 2012).
    \19\ Ozone season for CSAPR purposes is May 1 through September
30.
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    Following the issuance of CSAPR, the EPA determined that CSAPR
would achieve greater reasonable progress towards improving visibility
than would source-specific BART in CSAPR States (a determination often
referred to as ``CSAPR Better-than-BART'').\20\ In the EPA's 2012
action promulgating CSAPR-Better-than-BART, the EPA used air quality
modeling to show that CSAPR met the two-pronged numerical test for a
BART alternative under 40 CFR 51.308(e)(3).\21\ In the same action, we
revised the Regional Haze Rule to allow States whose sources
participate in the CSAPR trading programs to rely on such participation
in lieu of requiring BART-eligible EGUs in the State to meet source-
specific emission limits reflective of BART controls as to the relevant
pollutant. In addition to allowing States to rely on CSAPR to address
BART requirements, the EPA issued limited disapprovals of a number of
States' regional haze SIPs, including the 2009 Regional Haze SIP
submittal from Texas, due to the States' reliance on CAIR, which had
been replaced by CSAPR.\22\ The EPA did not immediately promulgate a
FIP to address those aspects of the 2009 Regional Haze SIP submittal
from Texas subject to the

limited disapproval in order to allow more time for the EPA to assess
the remaining elements of the SIP.
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    \20\ 77 FR 33642 (June 7, 2012). This determination was upheld
by the D.C. Circuit. See Util. Air Regulatory Grp. v. EPA, 885 F.3d
714 (D.C. Cir. 2018).
    \21\ See generally 77 FR 33642 (June 7, 2012).
    \22\ Id.
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    In December 2014, we proposed an action to address the remaining
regional haze obligations for Texas.\23\ In that action, we proposed,
among other things, to rely on our CSAPR FIP requiring Texas sources'
participation in the CSAPR trading programs to satisfy the
NOX and SO2 BART requirements for Texas's BART-
eligible EGUs consistent with the 2012 revisions to the Regional Haze
Rule. We also proposed to approve the portions of the 2009 Texas
Regional Haze SIP addressing PM BART requirements for the State's BART-
eligible EGUs. Before that proposed rule was finalized, however, the
D.C. Circuit issued a decision on a number of challenges to CSAPR,
denying most claims, but remanding the CSAPR SO2 and/or
seasonal NOX emissions budgets of several States to the EPA
for reconsideration, including the Phase 2 SO2 and seasonal
NOX budgets for Texas.\24\ Due to the uncertainty arising
from the remand of Texas's CSAPR budgets, we did not finalize our
December 2014 proposal to rely on CSAPR to satisfy the SO2
and NOX BART requirements for Texas EGUs.\25\ Additionally,
because our proposed action on the PM BART provisions for EGUs was
dependent on how SO2 and NOX BART were satisfied,
we did not take final action on the PM BART elements of the 2009 Texas
Regional Haze SIP.\26\
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    \23\ 79 FR 74818 (Dec. 16, 2014).
    \24\ EME Homer City Generation, L.P. v. EPA (EME Homer City II),
795 F.3d 118, 132 (D.C. Cir. 2015). In 2012, several State,
industry, and other petitioners challenged CSAPR in the D.C.
Circuit, which stayed and then vacated the rule, ruling on only a
subset of petitioners' claims. See EME Homer City Generation, L.P.
v. EPA, 696 F.3d 7 (D.C. Cir. 2012). However, in April 2014 the
Supreme Court reversed the vacatur and remanded to the D.C. Circuit
for resolution of petitioners' remaining claims. See EPA v. EME
Homer City Generation, L.P., 572 U.S. 489 (2014). Following the
Supreme Court remand, the D.C. Circuit conducted further proceedings
to address petitioners' remaining claims. In July 2015, the court
issued a decision denying most of the claims but remanding the Phase
2 SO2 emissions budgets for Alabama, Georgia, South
Carolina, and Texas and the Phase 2 ozone-season NOX
budgets for eleven States to the EPA for reconsideration.
    \25\ 81 FR 296 (Jan. 5, 2016).
    \26\ In January 2016, we finalized action on the remaining
aspects of the December 2014 proposal. This final action
disapproved, among other things Texas's reasonable progress analysis
and Texas's long-term strategy. The EPA promulgated a FIP
establishing a new long-term strategy that consisted of
SO2 emission limits for 15 coal-fired EGUs at eight power
plants. 81 FR 296, 302 (Jan. 5, 2016). That rulemaking was
judicially challenged, however, and in July 2016, the Fifth Circuit
granted the petitioners' motion to stay the rule pending review.
Texas v. EPA, 829 F.3d 405 (5th Cir. 2016). On March 22, 2017,
following the submittal of a request by the EPA for a voluntary
remand of the parts of the rule under challenge, the Fifth Circuit
Court of Appeals remanded the rule in its entirety. (In this
rulemaking, we are not addressing those remanded requirements.)
March 22, 2017, Order, Texas v. EPA, 829 F.3d 405 (5th Cir. 2016)
(No. 16-60118).
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    On October 26, 2016, the EPA finalized an update to CSAPR to
address the interstate transport requirements of CAA section
110(a)(2)(D)(i)(I) with respect to the 2008 ozone NAAQS (CSAPR
Update).\27\ The EPA also responded to the D.C. Circuit's remand in EME
Homer City II of certain CSAPR seasonal NOX budgets in that
action.\28\ As to Texas, the EPA withdrew Texas's seasonal
NOX budget finalized in CSAPR to address the 1997 ozone
NAAQS. However, in that same action, the EPA promulgated a FIP with a
revised seasonal NOX budget for Texas to address the 2008
ozone NAAQS.\29\ Accordingly, Texas sources remain subject to CSAPR
seasonal NOX requirements.
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    \27\ 81 FR 74504 (Oct. 26, 2016).
    \28\ See generally EME Homer City II, 795 F.3d 118, (D.C. Cir.
2015).
    \29\ 81 FR 74504, 74524-25.
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    On November 10, 2016, in response to the D.C. Circuit's remand in
EME Homer II of Texas's CSAPR SO2 budget, we proposed to
withdraw the FIP provisions that required EGUs in Texas to participate
in the CSAPR trading programs for annual emissions of SO2
and NOX.\30\ The EPA indicated that if the withdrawal was
finalized, Texas would no longer be eligible under 40 CFR 51.308(e)(4)
to rely on participation of its EGUs in a CSAPR trading program as an
alternative to source-specific SO2 BART determinations.\31\
We also proposed to reaffirm the EPA's 2012 analytical demonstration
that CSAPR provides greater reasonable progress than BART despite the
changes in CSAPR's geographic scope to address the EME Homer City II
remand, including removal of Texas's EGUs from the CSAPR trading
program for SO2 emissions.\32\ On September 29, 2017, we
finalized the withdrawal of the FIP provisions for annual emissions of
SO2 and NOX for EGUs in Texas \33\ and affirmed
our proposed finding that the EPA's 2012 analytical demonstration
remains valid and that participation in the CSAPR trading programs as
amended continues to meet the Regional Haze Rule's criteria for an
alternative to BART.\34\ (We refer to this as the ``2017 Affirmation of
CSAPR Better-than-BART'' throughout this notice.) In the September 29,
2017, final rule we evaluated the potential emissions shifting that
could occur due to the withdrawal of Texas from the CSAPR trading
program for SO2 emissions. Based on this evaluation, we
determined that an increase in emissions in the remaining CSAPR States
participating in the SO2 trading program would be more than
offset by the favorable visibility impacts brought about by the reduced
emissions in Texas under presumptive source-specific SO2
BART for the State's BART-eligible EGUs.\35\ As discussed later in this
section, certain environmental organizations filed a petition for
reconsideration of this affirmation in November 2017.
---------------------------------------------------------------------------

    \30\ 81 FR 78954 (Nov. 10, 2016).
    \31\ Id. at 78956. The EPA also noted that because Texas EGUs
would continue to participate in a CSAPR trading program for ozone-
season NOX emissions, Texas would still be eligible under
40 CFR 51.308(e)(4) to rely on CSAPR participation as an alternative
to source-specific NOX BART determinations for the
covered sources. 81 FR at 78962.
    \32\ Id.
    \33\ Texas continues to participate in CSAPR for ozone season
NOX. See final action signed September 21, 2017,
available at regulations.gov in Docket No. EPA-HQ-OAR-2016-0598.
    \34\ 82 FR 45481 (September 29, 2017).
    \35\ Id. at 45493-94.
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    On January 4, 2017, we proposed a FIP to address the BART
requirements for Texas's BART-eligible EGUs. With respect to
NOX, we proposed to replace the 2009 Regional Haze SIP's
reliance on CAIR with reliance on our CSAPR FIP to address the
NOX BART requirements for EGUs.\36\ This portion of our
proposal was based on the CSAPR Update and our separate November 10,
2016, proposed finding that the EPA's actions in response to the D.C.
Circuit's remand would not adversely impact our 2012 demonstration that
participation in the CSAPR trading programs meets the Regional Haze
Rule's criteria for alternatives to BART.\37\ We noted that we could
not finalize this portion of our proposed FIP to address the
NOX BART requirements for EGUs unless and until we finalized
our proposed finding that CSAPR was still better than BART.\38\ (This
predicate finding was finalized on September 29, 2017.)
---------------------------------------------------------------------------

    \36\ 82 FR 912, 914-15 (Jan. 4, 2017).
    \37\ 81 FR 74504 (Nov. 10, 2016).
    \38\ 82 FR 912, 915 (Jan. 4, 2017).
---------------------------------------------------------------------------

    The January 4, 2017, proposed action addressing the SO2
BART requirements for Texas EGUs acknowledged that Texas sources would
no longer be participating in the CSAPR program for SO2, and
therefore, the remaining unfulfilled BART requirements for Texas's
BART-eligible EGUs would need to be fulfilled by either an approved SIP
or an EPA-issued FIP. The EPA proposed to satisfy these requirements
through a BART FIP,

which addressed the identification of BART-eligible EGU sources,
screening to identify which BART-eligible sources are ``subject-to-
BART'' (i.e., may reasonably be anticipated to cause or contribute to
any impairment of visibility in any Class I area), and source-by-source
determinations of SO2 BART controls as appropriate. We
proposed SO2 emission limits on 29 EGUs located at 14
facilities.
    In the January 2017 proposal, we also proposed to disapprove the
portion of the 2009 Texas Regional Haze SIP that made BART
determinations for PM from EGUs, on the grounds that the demonstration
in the 2009 Texas Regional Haze SIP relied on underlying assumptions as
to how the SO2 and NOX BART requirements for EGUs
were being met that were no longer valid with the proposed source-
specific SO2 requirements.\39\ The 2009 Texas Regional Haze
SIP included a pollutant-specific screening analysis for PM to
demonstrate that Texas EGUs were not subject to BART for PM. In a 2006
guidance document,\40\ the EPA stated that pollutant-specific screening
can be appropriate where a State is relying on a BART alternative to
address both NOX and SO2 BART. While we
previously proposed to approve the EGU BART determinations for PM in
the 2009 Texas Regional Haze SIP back in 2014, at that time, CSAPR was
an appropriate alternative for SO2 and NOX BART
requirements for EGUs. With the proposal to promulgate source-specific
SO2 BART requirements, however, SO2 BART would no
longer be addressed by a BART alternative. Thus, pollutant-specific
screening for PM was no longer appropriate. To address PM BART
requirements, we proposed to promulgate source-specific PM BART
requirements, which generally were based on existing practices and
control capabilities for those EGUs that we proposed to find subject to
BART. For coal-fired units, we proposed PM BART limits consistent with
PM emission limits in the Mercury and Air Toxics Standards (MATS) rule;
for gas-fired units, we proposed PM BART would be satisfied by making
the burning of pipeline-quality gas federally enforceable; and for oil-
fired units, we proposed that fuel-content requirements for
SO2 BART would also satisfy PM BART.\41\
---------------------------------------------------------------------------

    \39\ In the 2009 Regional Haze Texas SIP, emissions of both
SO2 and NOX from Texas's BART-eligible EGUs
were covered by participation in trading programs, which allowed
Texas to conduct a screening analysis of the visibility impacts from
PM emissions from such units in isolation. However, modeling on a
pollutant specific basis for PM is appropriate only in the narrow
circumstance of reliance on BART alternatives to satisfy both
NOX and SO2 BART. Due to the complexity and
nonlinear nature of atmospheric chemistry and chemical
transformation among pollutants, the EPA has not recommended
performing modeling on a pollutant-specific basis to determine
whether a source is subject to BART, except in the unique situation
described above. See discussion in Memorandum from Joseph Paisie to
Kay Prince, ``Regional Haze Regulations and Guidelines for Best
Available Retrofit Technology (BART) Determinations,'' July 19,
2006.
    \40\ See discussion in Memorandum from Joseph Paisie to Kay
Prince, ``Regional Haze Regulations and Guidelines for Best
Available Retrofit Technology (BART) Determinations,'' July 19,
2006.
    \41\ 82 FR at 936.
---------------------------------------------------------------------------

    The EPA received public comments on this 2017 proposal encouraging
the agency to consider other potentially viable methods of implementing
a BART alternative for SO2 in Texas, rather than finalizing
source-specific BART limits. Specifically, some commenters suggested to
the EPA the concept of a trading program as a BART alternative to
satisfy SO2 BART requirements. After considering these and
other public comments, rather than finalizing source-specific BART
limits for subject-to-BART EGUs in Texas, we issued a final action on
October 17, 2017, that addressed SO2 BART requirements for
all BART-eligible coal-fired units and a number of BART-eligible gas-
or gas/fuel oil-fired units through a BART alternative for
SO2--specifically, a new intrastate trading program (Texas
SO2 Trading Program). The remaining BART-eligible EGUs not
covered by the Texas SO2 Trading Program were determined to
be not subject to BART based on screening methods as described in our
January 2017 proposed rule and the associated BART Screening technical
support document (BART Screening TSD) for that action.\42\
---------------------------------------------------------------------------

    \42\ See document in regulations.gov at docket identification
number EPA-R06-OAR-2016-0611-0005.
---------------------------------------------------------------------------

    At the time, the EPA modeled the Texas SO2 Trading
Program after the CSAPR SO2 trading program. We determined
that the Texas SO2 Trading Program would achieve similar
emission reductions to CSAPR had the State continued to be subject to
the CSAPR trading program through a FIP or SIP. As such, we concluded
that the Texas program satisfied the clear-weight-of-evidence test
requirements for a BART alternative under 40 CFR 51.308(e)(2).\43\ As
finalized in October 2017, the Texas SO2 Trading Program
established an annual trading program budget of 238,393 tons allocated
to the covered units, as well as a Supplemental Allowance Pool budget
of 10,000 tons, for a total of up to 248,393 allowances potentially
available in each year on average.\44\ The Texas SO2 Trading
Program allowed ``banking'' of allowances for use in future years,
similar to the CSAPR trading programs, but unlike the CSAPR programs,
did not impose an ``assurance level'' above which annual emissions
would be penalized via a higher allowance-surrender ratio. The Texas
SO2 Trading Program did not include all EGUs that would have
been subject to CSAPR, but the EPA concluded that potential annual
emissions from the excluded units were relatively small (i.e., less
than 27,500 tons) and would not undermine its overall conclusion that
the Texas SO2 Trading Program was essentially equivalent in
design and stringency to the CSAPR program.\45\ In reaching that
conclusion, the EPA compared the annual average emission limit of
248,393 tons under the Texas SO2 Trading Program (combined
with estimated emissions for the non-covered EGUs) to a benchmark
figure of 317,100 tons of annual SO2 emissions evaluated for
EGUs in Texas in the 2012 CSAPR Better-Than-BART analysis.\46\
---------------------------------------------------------------------------

    \43\ 82 FR 48324, 48329-30, 48357 (Oct. 17, 2017). The EPA
initially determined that the Texas SO2 Trading Program
achieved greater reasonable progress than source-specific BART under
the clear-weight-of-evidence test in 40 CFR 51.308(e)(2), relying on
the EPA's national finding that CSAPR provides for greater
reasonable progress than BART and the fact that the Texas
SO2 Trading Program would achieve similar emission
reductions to CSAPR in Texas. See 82 FR at 48329-30.
    \44\ Id. at 48358.
    \45\ Id.
    \46\ Id. at 48359-60.
---------------------------------------------------------------------------

    In our final action on October 17, 2017, we also finalized our
January 2017 proposed determination that Texas's participation in
CSAPR's trading program for ozone-season NOX qualifies as an
alternative to source-specific NOX BART. Because Texas
continues to participate in CSAPR's trading program for ozone-season
NOX, we are not reopening this determination in this action.
Finally, because both NOX and SO2 were now once
again addressed by a BART alternative, we approved Texas's 2009
Regional Haze SIP's determination, based on a pollutant-specific
screening analysis, that Texas's EGUs are not subject to BART for PM.
    On November 28, 2017, Sierra Club and the National Parks
Conservation Association (NPCA) submitted a petition for partial
reconsideration of our September 2017 finding affirming that CSAPR
continues to satisfy requirements as a BART alternative.\47\

Among other things, the petitioners alleged that it was impracticable,
and indeed impossible, to comment on the relationship between the Texas
SO2 Trading Program and the CSAPR Better-than-BART analysis
in the final rule because the EPA did not finalize the Texas
SO2 Trading Program until after the final rule was signed
and the EPA had assumed presumptive source-specific SO2 BART
controls in the rulemaking record for the final rule.\48\ Petitioners
alleged, in particular, that the EPA's emissions shifting analysis
accounted for potential increases in emissions in remaining CSAPR
States of between 22,300 to 53,000 tons by assuming these emissions
would be offset by an estimated 127,300 tons of SO2 emission
reductions in Texas due to presumptive source-specific BART
controls.\49\ However, these petitioners alleged that this assumption
was proven false when the EPA promulgated the Texas SO2
Trading Program rather than source-specific BART.\50\ On this basis,
among other things, petitioners sought mandatory reconsideration of the
September 29, 2017 action under CAA section 307(d)(7)(B).
---------------------------------------------------------------------------

    \47\ Sierra Club and National Parks Conservation Association,
Petition for Partial Reconsideration of Interstate Transport of Fine
Particulate Matter: Revision of Federal Implementation Plan
Requirements for Texas; Final Rule; 82 FR 45481 (Sept. 29, 2017);
EPA-HQ-OAR-2016-0598; FRL-9968-46-OAR (submitted Nov. 28, 2017).
    \48\ Id. at 8-9.
    \49\ Id. at 13-14.
    \50\ Id.
---------------------------------------------------------------------------

    On December 15, 2017, the EPA received a separate petition from
Sierra Club, NPCA, and the Environmental Defense Fund (EDF) requesting
reconsideration of certain aspects of the October 2017 final rule
focused mainly on issues related to the Texas SO2 Trading
Program promulgated to address the SO2 BART requirement for
Texas EGUs.\51\ In response to the December 15, 2017, petition for
reconsideration and in light of the change in direction between the
EPA's proposed and final actions for SO2 BART in Texas, we
stated that we believed that certain aspects of the October 2017 final
rule could benefit from further public comment. Accordingly, on August
27, 2018, the EPA proposed to affirm in most respects the October 2017
final rule, including the Texas SO2 Trading Program, but
solicited public comment on certain issues including whether the Texas
SO2 Trading Program for certain EGUs in Texas met the
requirements for an alternative to BART for SO2 and our
approval of Texas's SIP determination that no sources are subject to
BART for PM.\52\
---------------------------------------------------------------------------

    \51\ Sierra Club, National Parks Conservation Association, and
Environmental Defense Fund Petition for Reconsideration of
Promulgation of Air Quality Implementation Plans; State of Texas;
Regional Haze and Interstate Visibility Transport Federal
Implementation Plan (Oct. 17, 2017) EPA-R06-OAR-2016-0611; FRL-9969-
07-Region 6 (submitted Dec. 15, 2017).
    \52\ 83 FR 43586, 43587.
---------------------------------------------------------------------------

    On November 14, 2019, partly in response to comments received on
its 2018 proposed affirmation, the EPA issued a supplemental proposal
to amend certain parts of the Texas SO2 Trading Program.\53\
The supplemental proposal included additional measures such as an
assurance level and penalty provisions. Specifically, these provisions
imposed a penalty surrender ratio of three-to-one on SO2
emissions exceeding a specified ``assurance level.'' \54\ The notice
also proposed a variability limit set at 7 percent of the trading
program budget (or 16,668 tons) and a resulting assurance level of 107
percent of the trading program budget (or 255,081 tons \55\) based on
the CSAPR methodology establishing such amounts for CSAPR States but
applied to Texas-specific data.\56\ The supplemental proposal also
included other minor changes with the goal of strengthening the overall
stringency of the program.\57\
---------------------------------------------------------------------------

    \53\ 84 FR 61850 (Nov. 14, 2019).
    \54\ Id. at 61853.
    \55\ In the final rule signed on June 29, 2020, we adjusted the
assurance level to 255,083 tons rather than the 255,081-ton
assurance level we proposed in the November 2019 supplemental
proposal. 85 FR 49170, 49183 (Aug. 12, 2020).
    \56\ The increment between a State's emissions budget and its
corresponding assurance level is referred to as a ``variability
limit,'' because the increment is designed to account for year-to-
year variability in electricity generation and associated emissions.
    \57\ 84 FR at 61855-56.
---------------------------------------------------------------------------

    On June 29, 2020, in two separate but concurrent actions, former
EPA Administrator Andrew Wheeler signed a final rule affirming, with
the proposed modifications from the supplemental proposal described
above, the Texas SO2 Trading Program as an alternative to
BART for SO2 for certain sources in Texas and signed a
letter denying the petition for reconsideration of the 2017 affirmation
of CSAPR Better-than-BART.\58\ Along with the denial of the petition,
the EPA also published in the docket the ``Cross-State Air Pollution
Rule (CSAPR) Better Than Best Available Retrofit Technology (BART)
Petition for Reconsideration Sensitivity Calculations'' \59\ to
demonstrate that, even accounting for the reduced stringency of the
Texas SO2 Trading Program as compared to source-specific
BART in Texas, and assuming a concomitant shift in SO2
emissions to remaining CSAPR States in the southeastern United States,
CSAPR remained a valid BART alternative.
---------------------------------------------------------------------------

    \58\ See 85 FR 49170 (Aug. 12, 2020) (affirming the Texas
SO2 Trading Program as an alternative to BART for certain
EGU sources in Texas). 85 FR 40286 (July 6, 2020) (providing notice
that the agency responded to a petition for partial reconsideration
of the 2017 affirmation of CSAPR better than BART).
    \59\ Docket document ID EPA-HQ-OAR-2016-0598-0034 available at
https://www.regulations.gov/docket/EPA-HQ-OAR-2016-0598.
---------------------------------------------------------------------------

    On August 28, 2020, the Sierra Club, NPCA, and Earthjustice
submitted a petition for partial reconsideration under CAA section
307(d)(7)(B) of the EPA's 2020 Denial of their November 2017 petition
for reconsideration (August 2020 petition).\60\ The petitioners alleged
that because the EPA presented the updated CSAPR Better-than-BART
sensitivity calculations for the first time in its 2020 denial of the
2017 Petition (and thus they were not afforded an opportunity to
comment), and because that updated analysis is of central relevance to
the September 2017 Final Rule, the EPA must reconsider both actions
under CAA section 307(d)(7)(B).\61\ The petitioners alleged that,
contrary to the EPA's conclusions in its 2020 Denial, the updated CSAPR
Better-than-BART analysis demonstrates that visibility improvement
under CSAPR is not equal to or greater than visibility improvement
under source-specific BART averaged over all 140 Class I areas, or the
60 eastern Class I areas covered by CSAPR.\62\ The August 2020 petition
will be discussed in further detail in Section V.
---------------------------------------------------------------------------

    \60\ Petition for Partial Reconsideration of Denial of Petition
for Reconsideration and Petition for Reconsideration of the
Interstate Transport of Fine Particulate Matter: Revision of Federal
Implementation Plan Requirements for Texas (Aug. 28, 2020), Docket
document ID EPA-HQ-OAR-2016-0598-0041, available in
www.regulations.gov.
    \61\ 2020 Pet. at 8.
    \62\ 2020 Pet. at 9.
---------------------------------------------------------------------------

    On October 13, 2020, we received a separate petition for partial
reconsideration from NPCA, Sierra Club, and Earthjustice, on our 2020
final rule affirming that the Texas SO2 Trading Program is a
valid alternative to SO2 BART requirements for Texas
EGUs.\63\ In the petition, Petitioner's allege that the EPA presented a
corrected sensitivity analysis for the first time on July 6, 2020, the
day the EPA published notice of its denial of the 2017 administrative
petition for reconsideration of the CSAPR Better-than-BART affirmation
and after the EPA signed the final rule affirming the Texas Regional
Haze BART FIP.

Specifically, the Petitioners alleged that the corrected sensitivity
analysis is the ``primary evidence'' for the EPA's conclusion that the
Texas SO2 Trading Program is a lawful and valid BART
alternative for SO2 under the Regional Haze Rule, and that
contrary to the EPA's assertions, the ``corrected'' analysis reveals
that the Texas SO2 Trading Program does not achieve greater
reasonable progress than source-specific BART, and therefore, is
arbitrary and contrary to the Clean Air Act and Regional Haze Rule.
Moreover, Petitioners contended that the corrected sensitivity analysis
demonstrates that visibility improvement under CSAPR, including the
Texas SO2 Trading Program, is not equal to or greater than
visibility improvement under source-specific BART averaged over all 140
Class I areas or the 60 eastern Class I areas generally within the
States covered under CSAPR. Because the EPA disclosed the updated
analysis for the first time on July 6, 2020, the Petitioners argued
that the grounds for the objections raised in this petition arose after
the period for public comment, which ended on January 13, 2020, for the
EPA's supplemental notice of proposed rulemaking (84 FR 61,850 (Nov.
14, 2019)). Thus, Petitioners alleged the petition met the requirements
for mandatory reconsideration under CAA section 307(d)(7)(B).
---------------------------------------------------------------------------

    \63\ Sierra Club, National Parks Conservation Association, and
Earthjustice Petition for Partial Reconsideration of Promulgation of
Air Quality Implementation Plans; State of Texas; Regional Haze and
Interstate Visibility Transport Federal Implementation Plan EPA-R06-
OAR-2016-0611 (dated Oct. 13, 2020).
---------------------------------------------------------------------------

    By letter dated June 22, 2021, the EPA acknowledged receipt of the
petition for partial reconsideration and, without conceding that the
conditions for mandatory reconsideration were necessarily met pursuant
to CAA section 307(d)(7)(B), the agency recognized that aspects of this
action warrant careful review, and potential modification, to ensure
our actions are fully consistent with the requirements of the Clean Air
Act and the Regional Haze Rule.\64\ The letter stated the EPA's intent
to reconsider certain aspects of the Texas Regional Haze BART action,
which we are proposing in this action.
---------------------------------------------------------------------------

    \64\ Letter from Joseph Goffman, Acting Assistant Administrator
Office of Air and Radiation, Re: Sierra Club and National Parks
Conservation Association, Petition for Partial Reconsideration of
Promulgation of Air Quality Implementation Plans; State of Texas;
Regional Haze and Interstate Visibility Transport Federal
Implementation Plan EPA-R06-OAR-2016-0611 (June 22, 2021) available
in Docket ID No. EPA-R06-OAR-2016-0611 or at https://www.epa.gov/system/files/documents/2021-07/tx-rh-bart-fip-response-signed_1.pdf.
---------------------------------------------------------------------------

D. Consultation With Federal Land Managers (FLMs)

    The Regional Haze Rule requires that a State, or the EPA if
promulgating a FIP, consult with FLMs before adopting and submitting a
required SIP or SIP revision or a required FIP or FIP revision. Under
40 CFR 51.308(i)(2), a State, or the EPA if promulgating a FIP, must
provide an opportunity for consultation no less than 60 days prior to
holding any public hearing or other public comment opportunity on a SIP
or SIP revision, or FIP or FIP revision, for regional haze. The EPA
must include a description of how it addressed comments provided by the
FLMs when considering a FIP or FIP revision. We consulted with the FLMs
(specifically, U.S. Fish and Wildlife Service, U.S. Forest Service, and
the National Park Service) on December 6, 2022. During the consultation
we provided an overview of our proposed actions. The FLMs signaled
support for our proposed action.\65\
---------------------------------------------------------------------------

    \65\ See ``Texas Regional Haze FLM Consultation 12-6-2022.xls''
in the docket for this action.
---------------------------------------------------------------------------

III. Overview of Proposed Action

    In this notice of proposed rulemaking, the EPA proposes an action
with several interrelated components. As more fully explained in the
following sections, on reconsideration, and due to concerns that our
justification for the Texas SO2 Trading Program rested on an
erroneous interpretation of our BART alternative regulations, we are
proposing to withdraw the Texas SO2 Trading Program and
instead propose source-specific BART limits for certain EGUs in Texas.
We are proposing to satisfy the Regional Haze Rule's SO2
BART requirements through conducting a source-specific BART analysis
for certain BART-eligible EGU sources identified in this action.
Additionally, based on our assessment of the effect of this proposed
action with regard to Texas BART (if finalized), we are proposing to
re-affirm our 2017 analytical demonstration that CSAPR remains a valid
BART alternative. Thus, in this action we propose to deny the 2020
petition for partial reconsideration of our 2020 denial of a petition
for reconsideration of that 2017 determination. Finally, we are
proposing to make an error correction under CAA section 110(k)(6) with
respect to our prior approval of the portion of the 2009 Texas Regional
Haze SIP that found that Texas's EGUs are not subject to BART for PM on
the grounds that our approval relied on underlying assumptions as to
how the SO2 and NOX BART requirements for EGUs
were being met that are no longer valid with the proposed withdrawal of
the Texas SO2 Trading Program. As such, we propose to
correct the error by disapproving Texas's 2009 Regional Haze SIP
submission related to PM BART and propose to satisfy PM BART by also
conducting a source-specific BART analysis for certain BART-eligible
EGU sources identified in this action. Unless expressly reopened in
this notice, the EPA is not reopening any other prior determinations
related to regional haze requirements in the State of Texas.

IV. Withdrawal of the Texas SO2 Trading Program as a BART Alternative
for SO2

    As previously stated, on August 12, 2020, the EPA published a final
rule affirming our 2017 final rule that the Texas SO2
Trading Program, with amendments, satisfied the requirements for a BART
alternative for SO2 under 40 CFR 51.308(e)(2).\66\ In this
action, we are proposing to find that the basis for the Texas
SO2 Trading Program as a BART alternative rested on an
erroneous interpretation of our BART alternative regulations. That
interpretation in turn produced an analytical basis for the BART
alternative that we now propose to find insufficient and in error. We
are proposing to withdraw the Texas SO2 Trading Program
under CAA section 110(k)(6) and our inherent authority to reconsider
prior actions.
---------------------------------------------------------------------------

    \66\ See generally 85 FR 49170.
---------------------------------------------------------------------------

A. Legal Authority To Withdraw the Texas SO2 Trading Program

1. The EPA's Error Correction Authority Under CAA 110(k)(6)
    The EPA proposes to correct its Texas Regional Haze BART FIP by
proposing to withdraw the Texas SO2 Trading Program and
proposing to instead conduct a source-specific BART analysis for the
BART-eligible EGUs included in the Texas SO2 Trading
Program. In this action, we are proposing to find that the Texas
SO2 Trading Program was promulgated on an erroneous basis,
constituting an error under CAA section 110(k)(6).
    Section 110(k)(6) of the CAA provides the EPA with the authority to
make corrections to actions on CAA implementation plans that are
subsequently found to be in error. Ass'n of Irritated Residents v. EPA,
790 F.3d 934, 948 (9th Cir. 2015) (110(k)(6) is a ``broad provision''
enacted to provide the EPA with an avenue to correct errors). The key
provisions of section 110(k)(6) are that the Administrator has the
authority to ``determine'' that the promulgation of a plan was ``in
error,'' and when the Administrator does so, may then revise the action
``as

appropriate,'' in the same manner as the prior action.\67\ Moreover,
CAA section 110(k)(6) ``confers discretion on the EPA to decide if and
when it will invoke the statute to revise a prior action.'' 790 F.3d at
948 (section 110(k)(6) grants the ``EPA the discretion to decide when
to act pursuant to that provision'').
---------------------------------------------------------------------------

    \67\ See 85 FR 73636, 73637 (Nov. 19, 2020).
---------------------------------------------------------------------------

    While CAA section 110(k)(6) provides the EPA with the authority to
correct its own ``error,'' nowhere does this provision or any other
provision in the CAA define what qualifies as ``error.'' Thus, the EPA
believes that the term should be given its plain language, everyday
meaning, which includes all unintentional, incorrect, or wrong actions
or mistakes.\68\ Under CAA section 110(k)(6), the EPA must make an
error determination and provide the ``the basis thereof.'' There is no
indication that this is a substantial burden for the Agency to meet. To
the contrary, the requirement is met if the EPA clearly articulates the
error and basis thereof. Ass'n of Irritated Residents v. EPA, 790 F.3d
at 948; see also 85 FR 73636, 73638.
---------------------------------------------------------------------------

    \68\ See 85 FR at 73637-38.
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2. The EPA's Inherent Authority To Reconsider Its Prior Action
    In addition to the error correction provision of CAA section
110(k)(6), the EPA also has the inherent administrative authority to
withdraw the Texas SO2 Trading Program and propose in its
place to conduct a source-specific BART analysis for the BART-eligible
EGUs included in the Texas SO2 Trading Program. This
authority lies in CAA section 301(a), read in conjunction with CAA
section 110 and case law holding that an agency has inherent authority
to reconsider its prior actions.\69\ Section 301(a) authorizes the EPA
``to prescribe such regulations as are necessary to carry out the
[EPA's] functions'' under the CAA. Reconsidering prior rulemakings,
when necessary, is part of the ``[EPA's] functions'' under the CAA--
considering the EPA's inherent authority as recognized under the case
law to do so--and as a result, CAA section 301(a) confers authority
upon the EPA to undertake this rulemaking. Moreover, CAA section
110(c)(1) provides the EPA with the authority to promulgate a FIP where
``the Administrator . . . disapproves a State implementation plan
submission in whole or in part.'' As such, the EPA's authority to
promulgate FIPs under the CAA necessarily provides it the inherent
authority to amend/withdraw FIPs.\70\
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    \69\ Trujillo v. General Electric Co., 621 F.2d 1084, 1086 (10th
Cir. 1980) (``Administrative agencies have an inherent authority to
reconsider their own decisions, since the power to decide in the
first instance carries with it the power to reconsider.'')
    \70\ See 76 FR 25177, 25181 (May 2011).
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    Additionally, it is well-established that the EPA has discretion to
revisit existing regulations. Specifically, agencies have inherent
authority to reconsider past decisions and to revise, replace, or
repeal a decision to the extent permitted by law and supported by a
reasoned explanation. FCC v. Fox Television Stations, Inc., 556 U.S.
502, 515 (2009) (``Fox''); Motor Vehicle Manufacturers Ass'n of the
United States, Inc. v. State Farm Mutual Automobile Insurance Co., 463
U.S. 29, 42 (1983) (``State Farm''); see also Encino Motorcars, LLC v.
Navarro, 579 U.S. 211, 221-22 (2016).
    As such, we find that our inherent ability to reconsider past
actions also provides us the authority to withdraw the Texas
SO2 Trading Program for the same reasons as under CAA
section 110(k)(6), as described in Section IV.B. That is, because the
Texas SO2 Trading Program rested on what we find to be an
improper interpretation of our BART alternative regulations, we are
proposing to withdraw the program and to conduct a source-specific BART
analysis for those EGUs currently participating in the program.
    The EPA acknowledges the potential for reliance interests to be
affected by our reconsideration of a prior rule. However, the EPA is
not aware of any substantial commitment of resources or capital, or
that the EGUs covered by the Texas SO2 Trading Program
undertook any significant decisions in reliance on participation in the
trading program. The Texas SO2 Trading Program established
an emissions budget that the covered sources were already operating
well below. Therefore, the requirements of the Texas SO2
Trading Program did not cause any sources to invest in new pollution
control technology or to undertake any other significant investments.
Further, because the Texas SO2 Trading Program rested on an
improper interpretation of our BART alternative regulations, we do not
think a reliance interest alone (even if there were such interests)
would be sufficient to overcome the need to return to a proper
interpretation of our BART regulations and proper implementation of the
BART program.

B. Basis for Withdrawing the Texas SO2 Trading Program

    We propose that, in attempting to demonstrate that the Texas
SO2 Trading Program satisfied the BART alternative
requirements in 40 CFR 51.308(e)(2), the EPA erroneously relied on its
previous determination that the CSAPR trading program is better-than-
BART nationwide, when in fact the Texas SO2 Trading Program
was a separate BART alternative program that was not a part of the
CSAPR program.\71\ Because the Texas SO2 Trading Program was
and is separate and distinct from CSAPR and functioned as an
independent BART alternative disconnected from any other BART
alternative, we propose that in conducting the comparative analysis
required by 51.308(e)(2)(i), the EPA should have compared the
visibility benefits of the Texas SO2 Trading Program in
isolation with the visibility benefits of source-specific BART controls
for the particular subject-to-BART sources that would have been
required in the absence of the BART alternative. We conducted no such
comparison in either the 2017 rule originally promulgating the Texas
SO2 Trading Program, nor in the 2020 action affirming the
Texas SO2 Trading Program with certain, minor amendments.
For purposes of determining whether it is appropriate to now withdraw
the Texas SO2 Trading Program as a BART alternative, we have
conducted an analysis comparing the Texas SO2 Trading
Program to source-specific BART for the relevant EGU BART sources. We
propose to find that source-specific BART controls substantially
outperform the Texas SO2 Trading Program in terms of
emission reductions and visibility improvement at the Class I areas
that are affected by the sources in Texas. As a result of this finding
of error, we are proposing to withdraw the Texas SO2 Trading
Program as a BART alternative for SO2 and propose in its
place to conduct a source-specific BART analysis for those BART-
eligible EGUs included in the Texas SO2 Trading Program.
---------------------------------------------------------------------------

    \71\ See 82 FR 48324, 48330 (Oct. 17, 2017).
---------------------------------------------------------------------------

1. BART Alternative Requirements
    The Regional Haze Rule's BART provisions generally direct States to
identify all BART-eligible sources; determine which of those BART-
eligible sources are subject to BART requirements based on whether the
sources emit air pollutants that may reasonably be anticipated to cause
or contribute to visibility impairment in a Class I area; determine
source-specific BART for each source that is subject to BART
requirements, based on an analysis taking specified factors into
consideration; and include emission limitations reflecting those BART
determinations in their SIPs. However, the Regional Haze Rule also
provides

each State with the flexibility to adopt an allowance trading program
or other alternative measure instead of requiring source-specific BART
controls, so long as the alternative measure is demonstrated to achieve
greater reasonable progress than BART toward the national goal of
achieving natural visibility conditions in Class I areas.
    States, or the EPA if promulgating a FIP, that opt to rely on an
alternative program in lieu of source-specific BART, must meet the
requirements under 40 CFR 51.308(e)(2) and, if applicable, (e)(3).
These requirements for alternative programs establish the criteria for
demonstrating that the alternative program will achieve greater
reasonable progress than would be achieved through the installation and
operation of BART (i.e., they establish the ``better-than-BART'' tests)
and are fundamental elements of any alternative program. To demonstrate
that the alternative program achieves greater reasonable progress than
source-specific BART, States, or the EPA if developing a FIP, must
demonstrate that the alternative meets the requirements, as applicable,
in 40 CFR 51.308(e)(2)(i) through (vi). Separately, under 40 CFR
51.308(e)(4), States whose sources participate in the CSAPR trading
program(s) may rely on such programs to satisfy BART as to the relevant
pollutants and sources without the need for any additional analysis
(discussed in more detail in Section V).
    Under 40 CFR 51.308(e)(2), the State, or the EPA, must conduct an
analysis of the best system of continuous emission control technology
available and the associated emission reductions achievable for each
source subject to BART covered by the alternative program, termed a
``BART benchmark.'' \72\ Where the alternative program has been
designed to meet requirements other than BART, simplifying assumptions
may be used to establish a BART benchmark.\73\ The BART benchmark is
the basis for comparison in the better-than-BART test for BART
alternatives. Under 40 CFR 51.308(e)(2)(i)(E), the State or the EPA
must provide a determination that the alternative program achieves
greater reasonable progress than BART under 40 CFR 51.308(e)(3). 40 CFR
51.308(e)(3), in turn, provides two different avenues, applicable under
specific circumstances, for determining whether the BART alternative
achieves greater reasonable progress than BART. If the distribution of
emissions under the alternative program is not substantially different
than under BART, and the alternative program results in greater
emissions reductions of each relevant pollutant than BART, then the
alternative program may be deemed to achieve greater reasonable
progress. On the other hand, if the distribution of emissions is
significantly different, the differences in visibility improvement
between BART and the alternative program must be determined by
conducting dispersion modeling for each impacted Class I area for the
best and worst 20 percent of days. This modeling demonstrates ``greater
reasonable progress'' if both of the following criteria are met: (1)
Visibility does not decline in any Class I area; and (2) there is
overall improvement in visibility when comparing the average
differences in visibility conditions between BART and the alternative
program across all the affected Class I areas.\74\
---------------------------------------------------------------------------

    \72\ 40 CFR 51.308(e)(2)(i)(C).
    \73\ 40 CFR 51.308(e)(2)(i)(C).
    \74\ 40 CFR 51.308(e)(3).
---------------------------------------------------------------------------

    Alternatively, pursuant to 40 CFR 51.308(e)(2)(i)(E), a third test
is available under which States may show that the BART alternative
achieves greater reasonable progress than BART ``based on the clear
weight of evidence.'' As stated in the EPA's revisions to the Regional
Haze Rule governing alternatives to source-specific BART
determinations, such demonstrations attempt to make use of all
available information and data which can inform a decision while
recognizing the relative strengths and weaknesses of that information
in arriving at the soundest decision possible.\75\ Factors which can be
used in a weight of evidence determination in this context may include,
but are not limited to, future projected emissions levels under the
program as compared to under BART, future projected visibility
conditions under the two scenarios, the geographic distribution of
sources likely to reduce or increase emissions under the program as
compared to BART sources, monitoring data and emissions inventories,
and sensitivity analyses of any models used. This array of information
and other relevant data may be of sufficient quality to inform the
comparison of visibility impacts between BART and the alternative
program. In showing that an alternative program is better than BART and
when there is confidence that the difference in visibility impacts
between BART and the alternative scenarios are expected to be large
enough, a weight of evidence comparison may be warranted in making the
comparison.
---------------------------------------------------------------------------

    \75\ 71 FR 60612, 60622 (Oct. 13, 2006).
---------------------------------------------------------------------------

    Under 40 CFR 51.308(e)(2)(iii) and (iv), all emission reductions
for the alternative program must take place during the period of the
first long-term strategy (i.e., the first planning period) for regional
haze and all the emission reductions resulting from the alternative
program must be surplus to those reductions resulting from measures
adopted to meet requirements of the CAA as of the baseline date of the
SIP.
2. The EPA Inappropriately Relied on CSAPR When Promulgating and
Affirming the Texas SO2 Trading Program in 2017 and 2020
    The EPA has long maintained that the CSAPR trading programs can
function as a BART alternative for the relevant covered visibility
pollutants for the EGU BART sources that are covered by the relevant
CSAPR trading program. The EPA promulgated CSAPR, a revised multistate
trading program to replace CAIR, in 2011 (and revised it in 2012).\76\
CSAPR established FIP requirements for several States, including Texas,
to address the States' interstate transport obligation under CAA
section 110(a)(2)(D)(i)(I). The EPA made the original CSAPR better-
than-BART determination in a 2012 rulemaking, codified at 40 CFR
51.308(e)(4), and subsequently reaffirmed that determination in a 2017
rulemaking.\77\ At the time of the 2012 rulemaking, Texas was part of
the CSAPR annual NOX and SO2 trading programs to
address interstate transport of PM2.5. Therefore, Texas was
among the States who could choose to meet BART obligations for their
EGUs through participation in the relevant CSAPR trading program. The
EPA subsequently withdrew Texas from CSAPR for purposes of addressing
interstate transport requirements for the PM2.5 NAAQS (i.e.,
Texas was withdrawn from the annual NOX and SO2
trading programs) in response to the D.C. Circuit Court's decision in
EME Homer City Generation, L.P. v. EPA.\78\ However, when the EPA
promulgated the Texas SO2 Trading Program, the Agency
reasoned that it could nonetheless

satisfy the Regional Haze Rule's BART alternative requirements by
demonstrating that SO2 emissions under the Texas
SO2 Trading Program were comparable to SO2
emissions anticipated from Texas had Texas remained in CSAPR.\79\
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    \76\ Federal Implementation Plans; Interstate Transport of Fine
Particulate Matter and Ozone and Correction of SIP Approvals, 76 FR
48208 (Aug. 8, 2011).
    \77\ 77 FR 33642 (June 7, 2012) (codified at 40 CFR
51.308(e)(4)). The final rule amended the Regional Haze Rule to
allow States whose EGUs participate in one of the CSAPR trading
programs for a given pollutant to rely on that participation as an
alternative to source-specific BART requirements); see also 82 FR
45481 (Sep 29, 2017) (affirming that CSAPR remained better than BART
nationwide after Texas and other States were removed from CSAPR for
PM).
    \78\ EME Homer City Generation, L.P. v. EPA, 795 F. 3d 118, 138
(D.C. Cir. 2015).
    \79\ 82 FR 48324, 48336 (Oct. 17, 2017).
---------------------------------------------------------------------------

    As we explained in our June 2020 affirmation of the Texas
SO2 Trading Program, annual SO2 emissions for
sources covered by the Texas SO2 Trading Program are
constrained by the annual budgets and an assurance level of 255,083
tons. The EPA then added to this amount an estimated 35,000 tons per
year of emissions from units not covered by the Texas SO2
Trading Program, but which would have been covered by the CSAPR
program. This yielded 290,083 tons of SO2, which was below
the 317,100-tons per year emissions level assumed for Texas sources
under CSAPR.\80\ Thus, rather than considering the Texas SO2
Trading Program in isolation as a BART alternative and comparing the
effects of that program to the effects of source-specific BART for the
relevant EGUs in Texas to determine whether it made ``greater
reasonable progress,'' the EPA instead relied on the CSAPR Better-than-
BART analysis as the basis for concluding that the Texas SO2
Trading Program provided greater reasonable progress than BART--even
though the Texas SO2 Trading Program was not connected in
any way to CSAPR and functioned as its own, independent BART
alternative.
---------------------------------------------------------------------------

    \80\ Promulgation of Air Quality Implementation Plans; State of
Texas; Regional Haze and Interstate Visibility Transport Federal
Implementation Plan 85 FR 49170, 49183 (Aug. 12, 2020).
---------------------------------------------------------------------------

    Such reliance is inconsistent with the requirements of the Regional
Haze Rule's requirements for a BART alternative in 40 CFR 51.308(e)(2),
which requires a comparison between the BART alternative and the BART
benchmark for the relevant sources.\81\ Because the Texas
SO2 Trading Program is an intrastate program, the effects of
that program should have been considered independently of CSAPR.
Indeed, participation in the CSAPR program in lieu of implementing BART
requirements is provided for under a separate provision of the Regional
Haze Rule, 40 CFR 51.308(e)(4). Thus, the EPA could only rely on the
analytical demonstrations made in the CSAPR better-than-BART
rulemakings had Texas remained in CSAPR.\82\ Once Texas was withdrawn
from CSAPR, the EPA could not rely on that provision as justification
that the Texas SO2 Trading Program made ``greater reasonable
progress'' than BART at Texas EGUs. Thus, whether the Texas
SO2 Trading Program provided similar or more reductions than
anticipated had Texas remained in CSAPR is irrelevant and fails to
demonstrate that it achieves greater reasonable progress than BART as
required by 40 CFR 51.308(e)(2).
---------------------------------------------------------------------------

    \81\ 40 CFR 51.308(e)(2).
    \82\ Even after the removal of Texas (and other States) from
CSAPR following the remand of certain CSAPR budgets in EME Homer
City Generation, Texas (and other States) had the option to
voluntarily participate in CSAPR to gain the benefit of addressing
BART obligations. Texas declined to adopt this approach.
---------------------------------------------------------------------------

    Furthermore, although the Texas SO2 Trading Program was
modeled after CSAPR in its design and operation, the two programs are
distinct. First, the sources covered under the Texas SO2
Trading Program do not include all the sources in Texas that were part
of the CSAPR trading program.\83\ Thus, the EPA had to rely on an
unenforceable emissions assumption of 35,000 tons per year from the
non-covered sources to allow for an apples-to-apples comparison between
the Texas program and the CSAPR program in terms of the universe of
sources analyzed.\84\ However, there was no obligation that the non-
covered sources would emit below that assumed level in perpetuity.
---------------------------------------------------------------------------

    \83\ See 85 FR 49170, 49184.
    \84\ 85 FR 49170, 49184.
---------------------------------------------------------------------------

    Second, CSAPR was designed as a regional trading program that
involved the participation of sources from many States over a wide
geographic area, as compared to the Texas SO2 Trading
Program, which is an intrastate trading program. As such, the Texas
SO2 Trading Program is limited to sources in Texas which
cannot trade allowances with sources in other States as is permitted
under CSAPR. Because of the scope of participation in CSAPR, in
demonstrating that CSAPR was Better-than-BART, the EPA was not required
by the rule to demonstrate that CSAPR achieves greater reasonable
progress than BART at every Class I area or in every State.\85\ Rather,
the EPA demonstrated that CSAPR achieved greater visibility improvement
than BART when visibility was averaged across all Class I areas.\86\ In
averaging visibility improvement from CSAPR across all the affected
Class I areas, the 2012 demonstration properly relied on the
substantial emission reductions anticipated to occur in the eastern
half of the country for which other States, which included Texas at the
time, could take advantage of without having to apply source-specific
BART.\87\ For example, SO2 emissions in Tennessee were
anticipated to be approximately 321,300 in a nationwide BART
scenario,\88\ but only approximately 66,700 under CSAPR.\89\ Similar
situations were also anticipated in several other States including Ohio
(546,700 tons of SO2 under a nationwide BART scenario
compared to only 190,000 tons under CSAPR); Indiana (454,500 tons of
SO2 under a nationwide BART scenario compared to only
202,900 tons under CSAPR); and Pennsylvania (222,600 tons of
SO2 under a BART scenario compared to only 134,500 tons
under CSAPR).\90\
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    \85\ See 77 FR at 33650.
    \86\ See e.g., 77 FR at 33650.
    \87\ Specifically, in the 2017 affirmation that CSAPR remains
better than BART after withdrawal of multiple States from CSAPR,
including Texas, we stated that the 2012 analytic demonstration
showed that the difference in emissions between the CSAPR scenario
plus BART elsewhere would lead to an overall reduction in
SO2 emission reductions for the overall modeled region of
773,000 tons as compared to application of source specific BART
nationwide. See memo entitled ``Sensitivity Analysis Accounting for
Increases in Texas and Georgia Transport Rule State Emissions
Budgets,'' Docket document ID No. EPA-HQ-OAR-2011-0729-0323 (May 29,
2012) (2012 CSAPR/BART sensitivity analysis memo), at 1-2, available
in the docket for this proposed action.
    \88\ For all BART-eligible EGUs in the Nationwide BART scenario
and for BART-eligible EGUs not subject to CSAPR for a particular
pollutant in the CSAPR + BART-elsewhere scenario, the modeled
emission rates were the presumptive EGU BART limits for
SO2 and NOX as specified in the BART
Guidelines (Appendix Y to 40 CFR part 51--Guidelines for BART
Determinations under the Regional Haze Rule), unless an actual
emission rate at a given unit with existing controls was lower, in
which case the lower emission rate was modeled. (For additional
details see Technical Support Document for Demonstration of the
Transport Rule as a BART Alternative, Docket document ID No. EPA-HQ-
OAR-2011-0729-0014 (December 2011) (2011 CSAPR/BART Technical
Support Document EPA-HQ-OAR-2011-0729-0014) in www.regulations.gov.
    \89\ See Technical Support Document for Demonstration of the
Transport Rule as a BART Alternative, Docket document ID No. EPA-HQ-
OAR-2011-0729-0014 (December 2011) (2011 CSAPR/BART Technical
Support Document EPA-HQ-OAR-2011-0729-0014), at table 2-4, also
available in the docket for this action at document ID EPA-R06-OAR-
2016-0611-0119.
    \90\ See Technical Support Document for Demonstration of the
Transport Rule as a BART Alternative, Docket ID No. EPA-HQ-OAR-2011-
0729-0014 (December 2011) (2011 CSAPR/BART Technical Support
Document), at table 2-4, available in www.regulations.gov, document
ID EPA-R06-OAR-2016-0611-0119.
---------------------------------------------------------------------------

    However, while CSAPR leads to greater emissions reductions overall
over the modeled region, we explained that for certain CSAPR States,
application of source-specific BART was projected to lead to greater
emission reductions than through participation in CSAPR. We explained
that this could occur in CSAPR States that have numerous BART-eligible
EGUs.\91\ One

such State where this was anticipated to occur was Texas. In the case
of Texas, the projected SO2 emissions from affected EGUs in
the modeled nationwide-BART scenario (139,300 tons per year) are
considerably lower than the projected SO2 emissions from the
affected EGUs in the CSAPR scenario (266,600 tons per year as modeled,
and up to approximately 317,100 tons, as addressed in the 2012 CSAPR/
BART sensitivity analysis memo).\92\ Thus, the application of
presumptive source-specific BART, instead of participation in the CSAPR
SO2 trading program, would have resulted in projected
emissions of 139,300 tons per year, a reduction in projected
SO2 emissions by between approximately 127,300 tons and
177,800 tons from the CSAPR SO2 trading program
emissions.\93\ As a result, a demonstration that the Texas
SO2 Trading Program achieves equivalent emissions reductions
as anticipated had Texas remained in CSAPR fails to demonstrate that
the Texas SO2 Trading Program achieves greater reasonable
progress than BART for the BART sources in Texas participating in the
Texas SO2 Trading Program. The comparison in estimated
emissions above strongly indicates this not to be the case.
---------------------------------------------------------------------------

    \91\ 81 FR 78954, 78962-63 (Nov. 10, 2016).
    \92\ 81 FR 78954, 78962-63 (Nov. 10, 2016).
    \93\ 81 FR 78954, 78962-63 (Nov. 10, 2016). As stated in both
the proposal and final rule withdrawing Texas from CSAPR
SO2 trading program, the 127,300-ton amount was described
as the minimum reduction in projected Texas SO2 emissions
because it did not reflect a 50,500-ton increase in the Texas
SO2 budget that occurred after the original CSAPR
scenario was modeled. If that budget increase had been reflected in
the original CSAPR scenario, modeled Texas EGU SO2
emissions in that scenario would likely have been higher,
potentially by the full 50,500-ton amount. The CSAPR budget increase
would have had no effect on Texas EGUs' modeled SO2
emissions under BART. Therefore, the 127,300-ton minimum estimate of
the reduction in projected Texas SO2 emissions caused by
removing Texas EGUs from CSAPR for SO2, which are
computed as the difference between Texas EGUs' collective emissions
in the original CSAPR scenario and the BART scenario, may be
understated by as much as 50,500 tons. See 82 FR at 45492; 81 FR at
78962-63.
---------------------------------------------------------------------------

    Thus, we propose that it was an error to allow the Texas
SO2 Trading Program to rely on a demonstration made for a
different and unconnected BART alternative (i.e., CSAPR) because it
failed to comport with the requirements in 40 CFR 51.308(e)(2).
Instead, the EPA should have assessed whether the Texas SO2
Trading Program provides for greater reasonable progress than BART for
those BART sources in Texas covered by the Texas SO2 Trading
Program.\94\
---------------------------------------------------------------------------

    \94\ See 40 CFR 51.308(e)(2), (e)(3).
---------------------------------------------------------------------------

3. The Texas SO2 Trading Program Does Not Achieve Greater
Reasonable Progress Than BART
    Because the 2017 Texas BART FIP and subsequent affirmation
improperly relied on CSAPR to support the validity of the Texas
SO2 Trading Program, there is no evidence in the record to
support a finding that the Texas SO2 Trading Program
provides for greater reasonable progress than BART when compared to the
proper BART benchmark (i.e., source specific BART for the sources in
Texas covered by the Texas SO2 Trading Program). Rather, the
relevant information indicates that had the Texas SO2
Trading Program been compared to the appropriate Texas-specific BART
benchmark, the analysis would have found that the Texas SO2
Trading Program does not provide for greater reasonable progress than
BART at the Class I areas affected by those sources.
    For purposes of determining whether it is appropriate to now
withdraw the Texas SO2 Trading Program as a BART
alternative, we have conducted an analysis comparing the effects of the
Texas SO2 Trading Program to source-specific BART for the
relevant EGU BART sources. The purpose of this analysis is not to
conduct a full re-evaluation of the Texas SO2 Trading
Program under each of the requirements of the BART-alternative
regulations of 40 CFR 51.308(e)(2). Rather, this analysis evaluates the
question of whether, even under conservative assumptions, the Texas
SO2 Trading Program, when compared to the proper BART
benchmark (source-specific BART for the relevant sources in Texas),
could possibly achieve greater reasonable progress. The analysis
confirms a stark disparity in outcomes, with the Texas SO2
Trading Program not securing any additional emission reductions and
even allowing for substantial SO2 emissions increases from
baseline levels while source-specific BART would achieve substantial
SO2 emissions decreases. We propose to find that the
installation and operation of source-specific BART controls
substantially outperform the Texas SO2 Trading Program in
terms of emission reductions and resulting visibility improvement at
the Class I areas that are affected by the sources in Texas, and that
the Texas SO2 Trading Program does not achieves greater
reasonable progress than BART as required by 40 CFR 51.308(e)(2).
    As we explained earlier in Section II and in our June 2020
affirmation of the Texas SO2 Trading Program as an
alternative to BART for SO2, annual SO2 emissions
for sources covered by the Texas SO2 Trading Program are
constrained by the annual budgets and an assurance level of 255,083
tons.\95\ The Texas SO2 Trading Program imposes a penalty
surrender ratio of three allowances for each ton of emissions in any
year in excess of the assurance level, which provides a disincentive
against emissions exceeding the assurance level. Added to this amount
is an estimated 35,000 tons per year of emissions from units not
covered by the Texas SO2 Trading Program, but which would
have been covered by the CSAPR program. This yields an estimated
290,083 tons of SO2 from all Texas EGUs. This is
significantly higher than the 139,300 tons per year estimated in the
nationwide BART only scenario for Texas EGUs in the 2012 CSAPR better
than BART demonstration. In other words, the presumptive BART scenario
developed for the 2012 demonstration would result in approximately
150,000 tons per year less SO2 emissions than the Texas
SO2 Trading Program scenario.
---------------------------------------------------------------------------

    \95\ 85 FR 49170, 49183 (Aug. 12, 2020).
---------------------------------------------------------------------------

    We note, however, that this comparison of emissions of the Texas
SO2 Trading Program and presumptive BART from the 2012 CSAPR
analysis does not account for recent facility shutdowns. Sandow,\96\
Big Brown,\97\ and Monticello \98\ retired in 2018. Welsh Unit 2
retired in 2016,\99\ and the J. T. Deely units retired at the end of
2018.\100\ While these retirements have resulted in overall emission
reductions, they have also resulted in a surplus of allowances that
serve to decrease or eliminate any
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    \96\ See letter dated February 14, 2018, from Kim Mireles of
Luminant to the TCEQ requesting to cancel certain air permits and
registrations for Sandow Steam Electric Station available in the
docket for this action at document ID EPA-R06-OAR-2016-0611-0143 for
Sandow Unit 4 and document ID EPA-R06-OAR-2016-0611-0134 for Sandow
Unit 5.
    \97\ See letter dated March 27, 2018, from Kim Mireles of
Luminant to the TCEQ requesting to cancel certain air permits and
registrations for Big Brown available in the docket for this action
at document ID EPA-R06-OAR-2016-0611-0130.
    \98\ See letter dated February 8, 2018, from Kim Mireles of
Luminant to the TCEQ requesting to cancel certain air permits and
registrations for Monticello available in the docket for this action
at document ID EPA-R06-OAR-2016-0611-0132.
    \99\ Welsh Unit 2 was retired on April 16, 2016, pursuant to a
Consent Decree (No. 4:10-cv-04017-RGK) and subsequently removed from
the Title V permit (permit no. O26). See ``TX197.183 Turk (Welsh)
Consent Decree 12.22.11'' (document ID EPA-R06-OAR-2016-0611-0138)
and ``TX187.129 AIR OP_O26-13404_Permits_Public_20160919_Project
File Folder_1410429 (document ID EPA-R06-OAR-2016-0611-0129) in the
docket for this action.
    \100\ See letters dated December 2021 from the TCEQ to Danielle
Frerich regarding the cancellation of air quality permits for the J.
T. Deely Units available in the docket for this action.

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regulatory pressure from the Texas SO2 Trading Program to
further decrease emissions from current levels. Under the Texas
SO2 Trading Program, retired units continue to be allocated
allowances for a period of five years.\101\ After that period, those
allowances are still allocated but to the supplemental allowance
pool.\102\ Sources participating in the Texas SO2 Trading
Program have flexibility to transfer allowances among multiple
participating units under the same owner/operator when planning
operations, and unused allowances can be banked for use in future
years.\103\ Furthermore, allowances are allocated from the supplemental
allowance pool each year if the reported emissions for an ownership
group exceeds the amount of allowances allocated to that group, with a
limit on these allocations in any year of 16,688 tons plus any
allowances added to the pool in that year from retired units. The
combination of allocations to retired units, banking of allowances, and
allocations from the supplemental allowance pool results in an excess
availability in allowances to cover the sources' emissions with the
only limitation being the assurance level.
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    \101\ 40 CFR 97.911(a)(2).
    \102\ 40 CFR 97.911(a)(2).
    \103\ See 45 FR at 49208.
---------------------------------------------------------------------------

    Because the Texas SO2 Trading Program contains both BART
and non-BART EGUs, we must establish emission estimates for both types
of units to compare the installation and operation of source-specific
BART for SO2 to the Texas SO2 Trading Program.
For the purposes of comparing the Texas SO2 Trading Program
to source-specific BART, we assume that all BART-eligible coal-fired
sources are subject to BART \104\ and that source-specific BART results
in emission reductions greater than or equal to those reductions
estimated based on a presumptive BART level of 0.15 lb/MMBtu.\105\
\106\ For the gas fired sources included in the Texas SO2
Trading Program, we assume that they are not subject to BART for
purposes of this analysis and thus treat them as non-BART sources.\107\
We note that an assumption of 95 percent control would result in lower
emissions than the 0.15 lb/MMBtu rate for all BART units, however, for
the purpose of this comparison, we are selecting a conservative (high)
estimate for presumptive BART limits to illustrate the large emission
reductions available through the installation and operation of BART
even at this conservatively high emission rate. We also note that the
assumption of 0.15 lb/MMBtu is more conservative than what was used for
these units in the 2012 CSAPR Better-than-BART analysis.
---------------------------------------------------------------------------

    \104\ This is consistent with our subject to BART screening
analysis below in Section VII.
    \105\ BART Guidelines, 70 FR 39104, 39131 (July 6, 2005). ``. .
., we are establishing a BART presumptive emission limit for coal-
fired EGUs greater than 200 MW in size without existing
SO2 control. These EGUs should achieve either 95 percent
SO2 removal, or an emission rate of 0.15 lb
SO2/MMBtu, unless a State determines that an alternative
control level is justified based on a careful consideration of the
statutory factors.''
    \106\ In Section VII of this proposed action, we evaluate and
identify which of the BART-eligible EGUs currently in the Texas
SO2 Trading Program are subject to BART sources as well
as the analysis of the five factors that inform the BART
determination for subject to BART sources. In Section VIII, we
provide our weighing of the factors and proposed determination on
source-specific BART requirements for these sources.
    \107\ We note that in Section VII we determined that W. A.
Parish Unit WAP4, which is gas fired, is subject to BART because it
is co-located with two other coal-fired BART units (Units WAP5 &
WAP6). Thus, in evaluating whether the BART-eligible units at W. A.
Parish were subject to BART we evaluated emissions from Units WAP4
with WAP5 & WAP6, which is consistent with the subject to BART
evaluation process as explained in Section VII. For Unit WAP4, we
are not assuming any further reductions due to application of BART
because of the inherently low levels of SO2 from firing
natural gas.
---------------------------------------------------------------------------

    To estimate emissions for BART sources, we multiplied the average
heat input from 2016-2020 by a presumptive BART emission rate of 0.15
lb/MMBtu.\108\ To obtain a conservative estimate for non-BART units, we
used the maximum annual emissions from the 2016-2020 period for each
unit. The use of the maximum annual emissions from the 2016-2020 period
for each non-BART unit provides a conservative assumption of emissions
anticipated from these units to represent a scenario in which they are
not participating in the Texas SO2 Trading Program. We then
added the estimated emissions from the BART units together with the
estimated emissions from the non-BART units to compare emissions
between the Texas SO2 Trading Program and BART. Sources that
have recently shutdown were not included in the analysis. In addition
to comparing emission levels under source-specific BART to the
assurance level of the Texas SO2 Trading Program, we also
consider the impact of source-specific BART on current emissions levels
under the program.
---------------------------------------------------------------------------

    \108\ The Fayette BART units (Units 1 and 2) are currently
operating well below 0.15 lb/MMBtu. For these units, the maximum
annual emissions from 2016-2020 were used in this comparison.
---------------------------------------------------------------------------

    Table 1 shows 2021 annual emissions in one column, and the other
column shows estimated emissions under the presumptive BART assumptions
plus the maximum annual emissions from the 2016-2020 period for those
non-BART units as described in the paragraph above. The 2021 emissions
are the most recent annual emissions available at the time of this
action and represent emissions under the Texas SO2 Trading
Program regulations, including the amended provisions in the 2020 final
action. Under these conservative assumptions, presumptive BART for
those BART-eligible units plus the maximum annual emissions from the
2016-2020 period for those non-BART units still results in an
approximately 32 percent reduction in total estimated emissions as
compared to actual emissions for these same sources as provided for
under the Texas SO2 Trading Program. This is a significant
reduction compared to actual emissions and far below the assurance
level of 255,083 tons per year. Additionally, in looking at only
subject-to-BART units, presumptive BART reduces emissions by more than
70,000 tons as compared to what those units are emitting under the
Texas SO2 Trading Program. The estimated emissions for the
BART sources under presumptive BART of 24,108 tons is also far below
the allowance allocations to these units of 96,487 tons of allowances
per year. As detailed in Section VIII, our determinations of source-
specific BART result in even larger emission reductions than what was
calculated here under these presumptive BART assumptions.

   Table 1--Comparison of Actual Emissions Under the Texas SO2 Trading
                   Program and Presumptive BART \109\
------------------------------------------------------------------------
                                                        Presumptive BART
                                                         emissions plus
                                       2021 Actual       max. emissions
                                     emissions (tons)     for non-BART
                                                             (tons)
------------------------------------------------------------------------
Total (SO2 Trading Program Units).            129,790             88,023
Total (Subject-to-BART units only)             96,601             24,108
------------------------------------------------------------------------

    Because the alternative program under review, the Texas
SO2 Trading Program, results in much higher emissions than
source-specific BART, we are proposing to find that the Texas
SO2 Trading Program does not meet the requirements of a BART
alternative under 40 CFR 51.308(e)(2). As discussed earlier, if the
distribution of emissions under the alternative program is not
substantially different than under BART, and the alternative program
results in greater emissions reductions of each relevant pollutant than
under BART, then the alternative program may be deemed to achieve
greater reasonable progress.\110\ The Texas SO2 Trading
Program under review does not result in greater emission reductions
than under BART. Rather, compared to the presumptive BART scenario,
emissions from sources covered by the Texas SO2 Trading
Program are similar or higher. Furthermore, the Texas SO2
Trading Program does not secure emission reductions at non-BART sources
in Texas to compensate for the higher than BART emissions at the Texas
BART sources. In these situations, a BART alternative program can only
achieve greater reasonable progress than BART when emission reductions
from non-BART sources are large enough (or the resulting visibility
benefits from those reductions are large enough) to compensate for
smaller emission reductions at BART sources than would be achieved
under source-specific BART.
---------------------------------------------------------------------------

    \109\ See ``Annual EI Texas thru 2021.xlsx'' available in the
docket for this action.
    \110\ 40 CFR 51.308(e)(2)(E), (e)(3).
---------------------------------------------------------------------------

    This finding that the Texas SO2 Trading Program, which
was designed to achieve a stringency level on par with CSAPR, does not
achieve greater reasonable progress than BART, when isolated to the
units in Texas, is not surprising, and it does not undermine the
continued validity of CSAPR as a BART-alternative in other States. As
discussed earlier in Section IV.B.2, the CSAPR program resulted in
large emission reductions anticipated to occur in the eastern half of
the country due to its coverage of both many BART sources and many non-
BART sources. However, this was not true for every State. Texas, for
instance, generally had higher emissions under the CSAPR BART
alternative compared to source-specific BART, since it had relatively
more BART-eligible sources compared to many other States in the eastern
United States. As discussed, Texas was removed from the CSAPR
SO2 trading program in September 2017, and therefore, cannot
rely on the reductions in the eastern half of the country brought about
by CSAPR because the Texas SO2 Trading Program is
independent of CSAPR. As an independent BART alternative, the Texas
SO2 Trading Program is deficient because it secures no
additional emission reductions from any non-BART sources and, as
demonstrated, the BART emission reductions that would need to be offset
are very large. Because the Texas SO2 Trading Program
secures no reductions (and in fact would have permitted significant
growth in emissions from current levels), the establishment of source-
specific BART emission limits would result in large additional emission
reductions by comparison that would result in comparatively greater
visibility benefits. Accordingly, the Texas SO2 Trading
Program does not provide for greater reasonable progress than the
installation and operation of BART, and therefore, fails to meet the
requirements for a BART alternative under the Regional Haze Rule. Thus,
we are proposing to withdraw the Texas SO2 Trading Program
and instead propose to satisfy the Regional Haze Rule's SO2
BART requirements through conducting a source-specific BART analysis
for certain BART-eligible EGU sources identified in Sections VII and
VIII of this action.

V. CSAPR Participation as a BART Alternative

A. Introduction

    If the proposed source-specific BART requirements in Texas are
finalized, the analytical basis within the EPA's withdrawal of Texas
from the CSAPR trading programs for annual NOX and
SO2 in September of 2017 will be restored (82 FR 45481).
Therefore, the EPA is proposing to find that, if this proposal to
implement source-specific BART requirements at certain EGUs in Texas is
finalized, the analytical basis for concluding that the implementation
of CSAPR in the remaining covered States will continue to meet the
criteria for a BART alternative for those States remains valid. Related
to this finding, the EPA is also proposing to deny a 2020
administrative petition for partial reconsideration brought by Sierra
Club, National Parks Conservation Association (NPCA), and Earthjustice
of the EPA's June 2020 denial of a 2017 petition to reconsider the
EPA's original September 2017 finding, the details of which are
provided in the next sections. Based on this analysis, the EPA is
affirming the current Regional Haze Rule provision allowing States
whose EGUs continue to participate in a CSAPR trading program for a
given pollutant to continue to rely on CSAPR participation as a BART
alternative for its BART-eligible EGUs for that pollutant. The public
is invited to comment on this proposed basis for denying the 2020
petition for partial reconsideration.

B. Background

1. CSAPR Better-Than-BART
a. General Background
    CSAPR (76 FR 48208; Aug. 8, 2011) implements a series of emissions
trading programs for sulfur dioxide (SO2) and nitrogen
oxides (NOX) across the eastern United States to address
interstate ozone and fine particulate (PM2.5) pollution
under CAA section 110(a)(2)(D)(i)(I) (the ``good neighbor
provision'').\111\ The EPA has issued regulations allowing the CSAPR
States to rely on participation in these trading programs in lieu of
requiring source-specific BART controls at their BART-eligible EGUs
covered by one or more of the CSAPR trading programs with respect to
the visibility pollutant at issue (i.e., NOX or
SO2). See

40 CFR 51.308(e)(4).\112\ This determination authorizing reliance on
CSAPR participation as a BART alternative is often referred to as
``CSAPR Better-Than-BART.'' \113\
---------------------------------------------------------------------------

    \111\ 42 U.S.C. 7410(a)(2)(D)(i)(I).
    \112\ The EPA had previously made a similar finding for the
predecessor to CSAPR, the Clean Air Interstate Rule (CAIR), and this
determination was upheld in UARG v. EPA, 471 F.3d 1333 (D.C. Cir.
2006) (UARG I).
    \113\ 77 FR 33642 (June 7, 2012).
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    In the EPA's 2012 action promulgating CSAPR Better-Than-BART, the
EPA used air quality modeling to show CSAPR met the two-pronged
numerical test for a BART alternative.\114\ To account for certain
CSAPR State-budget increases that were made after the initial modeling
was conducted, the 2012 CSAPR Better-Than-BART determination also
included a sensitivity analysis (2012 sensitivity analysis) that
examined the effect of those budget increases on the modeled visibility
impacts for the CSAPR scenario.\115\ In the 2012 action, the EPA found
that under a scenario analyzing the visibility benefits of CSAPR
(referred to as the ``CSAPR + BART-Elsewhere'' scenario), visibility
would not decline in any Class I area compared to a baseline scenario,
satisfying the first prong of the two-pronged BART-alternative test.
The EPA also found that the CSAPR + BART-Elsewhere scenario would
result in an overall improvement in visibility on average across
affected Class I areas, as compared to a scenario analyzing visibility
benefits resulting from ``presumptive'' BART limits at all BART-
eligible sources (referred to as the ``nationwide BART'' scenario),
satisfying the second prong of the two-pronged BART-alternative test.
The EPA's findings held true whether looking at the 60 Class I areas in
the eastern U.S. most heavily impacted by the sources subject to CSAPR
or looking at all 140 Class I areas in the continental United States.
The United States Court of Appeals for the D.C. Circuit (D.C. Circuit)
upheld this action in UARG v. EPA, 885 F.3d 714 (D.C. Cir. 2018) (UARG
II).
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    \114\ 40 CFR 51.308(e)(3); See generally 77 FR 33642 (June 7,
2012).
    \115\ See 77 FR 33642, 33651-52; This sensitivity analysis was
included in a technical memo accompanying the 2012 action. See
``Sensitivity Analysis Accounting for Increases in Texas and Georgia
Transport Rule State Budgets,'' Docket ID No. EPA-HQ-OAR-2011-0729
and in the docket for this action at document ID EPA-R06-OAR-2016-
0611-0113.
---------------------------------------------------------------------------

    To account for certain CSAPR State-budget increases that were made
after the initial modeling was conducted, the 2012 CSAPR Better-Than-
BART determination also included a sensitivity analysis (2012
sensitivity analysis) that examined the effect of those budget
increases on the modeled visibility impacts for the CSAPR + BART-
Elsewhere scenario.\116\ The EPA determined that the increases in
SO2 and NOX budgets were small enough that they
did not require a comprehensive set of new power sector and air quality
modeling. Instead, the 2012 sensitivity analysis applied a simple, but
very conservative adjustment factor to the existing quantitative air
quality modeling results to show that, even with the higher emissions
budgets, the CSAPR + BART-Elsewhere scenario was still projected to
show greater reasonable progress toward natural visibility than the
Nationwide BART scenario. Specifically, the 2012 sensitivity analysis
applied adjustments to visibility impacts in the CSAPR + BART-Elsewhere
scenario to account for increases in the SO2 budgets for
Texas and Georgia, since SO2-driven impacts were the most
important impacts in the analysis and Texas and Georgia had the largest
SO2 budget increases.
---------------------------------------------------------------------------

    \116\ See 77 FR 33642, 33651-52; This sensitivity analysis was
included in a technical memo accompanying the 2012 action. See
``Sensitivity Analysis Accounting for Increases in Texas and Georgia
Transport Rule State Budgets,'' Docket ID No. EPA-HQ-OAR-2011-0729
and in the docket for this action at document ID EPA-R06-OAR-2016-
0611-0113.
---------------------------------------------------------------------------

    The 2012 sensitivity analysis identified sets of Class I areas that
are most impacted by emissions in Texas (9 areas) and Georgia (7 areas)
and assumed that all of the modeled visibility improvement in those
sets of Class I areas is due to SO2 emissions reductions
from either Texas or Georgia, respectively. This methodology is highly
conservative because the projected SO2 emissions reductions
in Texas and Georgia represented only 4.4 percent and 1.8 percent,
respectively, of the total projected regional emissions reductions in
the CSAPR + BART-Elsewhere scenario, and the Class I areas most
impacted by Texas and Georgia emissions are also affected by the very
large emissions reductions projected from other States in the regional
CSAPR + BART-Elsewhere scenario. By assuming a linear relationship
between emissions increases in Texas and Georgia and visibility
degradation in those Class I areas, the EPA very conservatively
determined that even with the budget increases, the CSAPR + BART-
Elsewhere scenario was projected to achieve greater visibility
improvement than the Nationwide BART scenario on average across all 60
eastern Class I areas and all 140 nationwide Class I areas, thereby
satisfying the second prong of the two-pronged test under 40 CFR
51.308(e)(3). The sensitivity analysis also showed no visibility
degradation in the CSAPR + BART-Elsewhere scenario relative to the
baseline scenario at any Class I area, thereby satisfying the first
prong of the test.
b. The CSAPR Remand and the EPA's 2017 Affirmation of CSAPR Better-
Than-BART
    The original 2011 CSAPR action was largely upheld by the Supreme
Court in 2014.\117\ However, the case was remanded to the D.C. Circuit
to assess whether the EPA may have ``over-controlled'' certain States
for purposes of implementing the good neighbor provision. In EME Homer
City Generation, L.P. v. EPA, 795 F.3d 118 (D.C. Cir. 2015), based on
this potential for overcontrol, the court remanded certain State
budgets to the EPA, including Texas' SO2 budget, which the
EPA had established to address PM2.5 transport.
---------------------------------------------------------------------------

    \117\ EPA v. EME Homer City Generation, L.P., 572 U.S. 489
(2014).
---------------------------------------------------------------------------

    To address the remand, in November 2016, the EPA proposed to remove
Texas EGUs from the CSAPR SO2 Group 2 Trading Program as
well as the CSAPR NOX Annual Trading Program, which
similarly addressed PM2.5 transport.\118\ The EPA indicated
that if the withdrawal was finalized, Texas would no longer be eligible
under 40 CFR 51.308(e)(4) to rely on participation of its EGUs in a
CSAPR trading program as an alternative to source-specific
SO2 BART determinations.\119\ The EPA also provided a
proposed analysis (2016 proposed analysis) showing that the changes in
the geographic scope of CSAPR coverage since the EPA's original 2012
CSAPR Better-Than-BART determination, including the proposed withdrawal
of Texas EGUs from the CSAPR SO2 and annual NOX
trading programs, would not have altered the 2012 determination because
the changes would not have altered the EPA's analytical findings that
both prongs of the two-pronged test for a BART alternative under 40 CFR
51.308(e)(3) were satisfied.\120\
---------------------------------------------------------------------------

    \118\ See 81 FR 78954 (Nov. 10, 2016).
    \119\ Id. at 78956; the EPA also noted that because Texas EGUs
would continue to participate in a CSAPR trading program for ozone-
season NOX emissions, Texas would still be eligible under
40 CFR 51.308(e)(4) to rely on CSAPR participation as an alternative
to source-specific NOX BART determinations for the
covered sources. 81 FR at 78962.
    \120\ See id. at 78961-64.
---------------------------------------------------------------------------

    In September 2017, the EPA finalized the withdrawal of Texas EGUs
from the

CSAPR SO2 and annual NOX programs.\121\ In the
same action, the EPA also issued its final analysis (2017 final
analysis) showing that, even with Texas EGUs no longer participating in
these programs (and other changes in the geographic coverage of CSAPR),
the EPA's original 2012 analytical finding that CSAPR is better than
BART remained valid.\122\ In response to comments received on the 2016
proposed analysis, the EPA's 2017 final analysis included an evaluation
of the potential impact of emissions shifting under both prongs of the
two-pronged test for a BART alternative under 40 CFR 51.308(e)(3). This
analysis focused on the fact that if Texas sources were withdrawn from
the CSAPR SO2 Group 2 Trading Program, they would no longer
purchase up to 22,300 SO2 allowances from sources in other
Group 2 States, as had been projected in the CSAPR + BART-Elsewhere
scenario used in the 2012 CSAPR Better-Than-BART determination. As to
the first prong, the EPA explained that, relative to a baseline
scenario without CSAPR or BART, a revised CSAPR + BART-Elsewhere
scenario with an increased quantity of SO2 allowances
available for use by units in other Group 2 States would still show no
visibility degradation at any Class I area because, absent unusual
circumstances that the EPA showed were not expected to occur in this
case, all units in the remaining Group 2 States would still have
stronger incentives to control their SO2 emissions in the
revised CSAPR + BART-Elsewhere scenario (with some positive allowance
price) than in the baseline scenario (without any allowance
price).\123\
---------------------------------------------------------------------------

    \121\ See 82 FR 45481 (September 29, 2017).
    \122\ See id. at 45490-94.
    \123\ Id. at 45493.
---------------------------------------------------------------------------

    As to the second prong, the EPA assumed that the availability of
22,300 additional allowances would result in a 22,300-ton increase in
emissions in the remaining Group 2 States, but observed that the
potential adverse visibility impacts of those emissions would be more
than offset by the favorable visibility impacts of at least 127,300
tons of reduced emissions in Texas under presumptive source-specific
SO2 BART for the State's BART-eligible EGUs.\124\ In other
words, under the methodological framework the EPA devised in 2012 to
compare CSAPR with BART, see 77 FR 33648-49, the EPA concluded that the
``Transport Rule [CSAPR] + BART Elsewhere'' scenario would still
outperform the ``Nationwide BART'' scenario, even if Texas's EGU BART
sources fell under the ``BART Elsewhere'' category rather than the
CSAPR category. Thus, the EPA's conclusion that CSAPR satisfied the
second prong of the two-pronged test rested in part on assuming net
SO2 reductions of approximately 105,000 tons from
presumptive source-specific BART in Texas, after accounting for the
potential for shifting of 22,300 tons of emissions from Texas to the
remaining Group 2 States.\125\
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    \124\ Id. at 45493-94.
    \125\ 82 FR 45493-94.
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2. Promulgation and Affirmation of the Texas SO2 Trading
Program as a BART Alternative
    As explained in Section II.C, rather than finalize source-specific
BART SO2 emission limits for subject-to-BART EGUs in Texas
(as had been assumed in the September 2017 finding affirming CSAPR as
better than BART), the EPA took final action in October 2017
establishing an intrastate trading program for SO2 for