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Proposed Rule2024-23341

Air Quality State Implementation Plans; Partial Approval, Partial Disapproval and Promulgation; Texas; Regional Haze

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Published

October 15, 2024

Issuing agencies

Environmental Protection Agency

Abstract

The Environmental Protection Agency (EPA) is proposing to partially approve and partially disapprove the regional haze State implementation plan (SIP) revision submitted by Texas on July 20, 2021, under the Clean Air Act (CAA) and EPA's Regional Haze Rule (RHR) for the program's second implementation period. Texas's SIP submission addresses the requirement that states must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is taking this action pursuant to sections 110 and 169A of the Clean Air Act.

Full Text

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<title>Federal Register, Volume 89 Issue 199 (Tuesday, October 15, 2024)</title>
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[Federal Register Volume 89, Number 199 (Tuesday, October 15, 2024)]
[Proposed Rules]
[Pages 83338-83375]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-23341]

[[Page 83337]]

Vol. 89

Tuesday,

No. 199

October 15, 2024

Part V

Environmental Protection Agency

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40 CFR Part 52

Air Quality State Implementation Plans; Partial Approval, Partial
Disapproval and Promulgation; Texas; Regional Haze; Proposed Rule

Federal Register / Vol. 89 , No. 199 / Tuesday, October 15, 2024 /
Proposed Rules

[[Page 83338]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2021-0539; FRL-12282-01-R6]

Air Quality State Implementation Plans; Partial Approval, Partial
Disapproval and Promulgation; Texas; Regional Haze

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
partially approve and partially disapprove the regional haze State
implementation plan (SIP) revision submitted by Texas on July 20, 2021,
under the Clean Air Act (CAA) and EPA's Regional Haze Rule (RHR) for
the program's second implementation period. Texas's SIP submission
addresses the requirement that states must periodically revise their
long-term strategies for making reasonable progress towards the
national goal of preventing any future, and remedying any existing,
anthropogenic impairment of visibility, including regional haze, in
mandatory Class I Federal areas. The SIP submission also addresses
other applicable requirements for the second implementation period of
the regional haze program. The EPA is taking this action pursuant to
sections 110 and 169A of the Clean Air Act.

DATES: Written comments must be received on or before November 14,
2024.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R06-
OAR-2021-0539 at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the online
instructions for submitting comments. Once submitted, comments cannot
be edited or removed from <a href="http://Regulations.gov">Regulations.gov</a>. The EPA may publish any
comment received to its public docket. Do not submit electronically any
information you consider to be Confidential Business Information (CBI)
or other information whose disclosure is restricted by statute.
Multimedia submissions (audio, video, etc.) must be accompanied by a
written comment. The written comment is considered the official comment
and should include discussion of all points you wish to make. The EPA
will generally not consider comments or comment contents located
outside of the primary submission (i.e., on the web, cloud, or other
file sharing system). For additional submission methods, the full EPA
public comment policy, information about CBI or multimedia submissions,
and general guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>. For additional submission
methods, please contact the person identified in the FOR FURTHER
INFORMATION CONTACT section. For the full EPA public comment policy,
information about CBI or multimedia submissions, and general guidance
on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
Docket: The index to the docket for this action is available
electronically at <a href="http://www.regulations.gov">www.regulations.gov</a>. While all documents in the
docket are listed in the index, some information may not be publicly
available due to docket file size restrictions or content (e.g., CBI).

FOR FURTHER INFORMATION CONTACT: Jennifer Huser, U.S. Environmental
Protection Agency, Region 6, 1201 Elm St., Suite 500, Dallas, Texas
75270, at (214) 665-7347, or by email at <a href="/cdn-cgi/l/email-protection#ace4d9dfc9de82e6c9c2c2c5cac9deecc9dccd82cbc3da"><span class="__cf_email__" data-cfemail="6b231e180e1945210e0505020d0e192b0e1b0a450c041d">[email&#160;protected]</span></a>.

SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' or ``our'' is used, we mean the EPA.

Table of Contents

I. What action is the EPA proposing?
II. Background and Requirements for Regional Haze Plans
A. Regional Haze Background
B. Roles of Agencies in Addressing Regional Haze
III. Requirements for Regional Haze Plans for the Second
Implementation Period
A. Identification of Class I Areas
B. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
C. Long-Term Strategy for Regional Haze
D. Reasonable Progress Goals
E. Monitoring Strategy and Other State Implementation Plan
Requirements
F. Requirements for Periodic Reports Describing Progress Towards
the Reasonable Progress Goals
G. Requirements for State and Federal Land Manager Coordination
IV. The EPA's Evaluation of Texas's Regional Haze Submission for the
Second Implementation Period
A. Background on Texas's First Implementation Period SIP
Submission
B. Texas's Second Implementation Period SIP Submission and the
EPA's Evaluation
C. Identification of Class I Areas
1. Texas Class I Areas
2. Identification of Impacted Class I Areas Outside the State
D. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
E. Long-Term Strategy for Regional Haze
1. Source Selection
2. Four Factor Analysis
3. Additional Long-Term Strategy Requirements
F. Reasonable Progress Goals
G. Reasonably Attributable Visibility Impairment (RAVI)
H. Monitoring Strategy and Other Implementation Plan
Requirements
I. Requirements for Periodic Reports Describing Progress Towards
the Reasonable Progress Goals
J. Requirements for State and Federal Land Manager Coordination
V. Proposed Action
VI. Environmental Justice Considerations
VII. Statutory and Executive Order Reviews

I. What action is the EPA proposing?

On July 20, 2021, the Texas Commission on Environmental Quality
(TCEQ) submitted a plan (``2021 Texas Regional Haze Plan'' or ``Texas
RH SIP'') to the EPA to satisfy the regional haze program requirements
pursuant to CAA sections 169A and 40 CFR 51.308. The EPA is proposing
to partially approve and partially disapprove Texas's Regional Haze
plan for the second planning (implementation) period. Consistent with
section 110(k)(3) of the CAA, the EPA may partially approve portions of
a submittal if those elements meet all applicable requirements and may
disapprove the remainder so long as the elements are fully
separable.\1\ As required by section 169A of the CAA, the Federal RHR
calls for State and Federal agencies to work together to improve
visibility in 156 national parks and wilderness areas. The rule
requires the states, in coordination with the EPA, National Park
Service (NPS), U.S. Fish and Wildlife Service (FWS), Forest Service
(FS), and other interested parties, to develop and implement air
quality protection plans to reduce the pollution that causes visibility
impairment. Visibility impairing pollutants include fine and coarse
particulate matter (PM) (e.g., sulfates, nitrates, organic carbon,
elemental carbon, and soil dust) and their precursors (e.g., sulfur
dioxide (SO<INF>2</INF>), nitrogen oxides (NO<INF>X</INF>), and, in
some cases, volatile organic compounds (VOC) and ammonia
(NH<INF>3</INF>)). As discussed in further detail below, the EPA is
proposing to find that Texas has submitted a Regional Haze plan that
does not meet all the Regional Haze requirements for the second
planning period. For the reasons described in this document, the EPA is
proposing to approve the elements of Texas's plan related to
requirements contained in 40

[[Page 83339]]

CFR 51.308(f)(1), (f)(4), (f)(5),\2\ and (f)(6). The EPA is proposing
to disapprove the elements of Texas's plan related to requirements
contained in 40 CFR 51.308(f)(2), (f)(3), and (i). The State's
submission can be found in the docket for this action.
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\1\ See CAA section 110(k)(3) and July 1992 EPA memorandum
titled ``Processing of State Implementation Plan (SIP) Submittals''
from John Calcagni, at <a href="https://www.epa.gov/sites/default/files/2015-07/documents/procsip.pdf">https://www.epa.gov/sites/default/files/2015-07/documents/procsip.pdf</a>.
\2\ 40 CFR 51.308(f)(5) requires that the second planning period
SIP revision address the requirements listed in (g)(1) through
(g)(5).
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II. Background and Requirements for Regional Haze Plans

A. Regional Haze Background

In the 1977 CAA Amendments, Congress created a program for
protecting visibility in the nation's mandatory Class I Federal areas,
which include certain national parks and wilderness areas.\3\ CAA 169A.
The CAA establishes as a national goal the ``prevention of any future,
and the remedying of any existing, impairment of visibility in
mandatory class I Federal areas which impairment results from manmade
air pollution.'' CAA 169A(a)(1). The CAA further directs the EPA to
promulgate regulations to assure reasonable progress toward meeting
this national goal. CAA 169A(a)(4). On December 2, 1980, the EPA
promulgated regulations to address visibility impairment in mandatory
Class I Federal areas (hereinafter referred to as ``Class I areas'')
that is ``reasonably attributable'' to a single source or small group
of sources. (45 FR 80084, December 2, 1980). These regulations,
codified at 40 CFR 51.300 through 51.307, represented the first phase
of the EPA's efforts to address visibility impairment. In 1990,
Congress added section 169B to the CAA to further address visibility
impairment, specifically, impairment from regional haze. CAA 169B. The
EPA promulgated the RHR, codified at 40 CFR 51.308,\4\ on July 1, 1999.
(64 FR 35714, July 1, 1999). These regional haze regulations are a
central component of the EPA's comprehensive visibility protection
program for Class I areas.
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\3\ Areas statutorily designated as mandatory Class I Federal
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. CAA
162(a). There are 156 mandatory Class I areas. The list of areas to
which the requirements of the visibility protection program apply is
in 40 CFR part 81, subpart D.
\4\ 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 applicable only for specific jurisdictions' regional
haze plans submitted no later than December 17, 2007, and thus are
not relevant here.
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Regional haze is visibility impairment that is produced by a
multitude of anthropogenic sources and activities which are located
across a broad geographic area and that emit pollutants that impair
visibility. Visibility impairing pollutants include fine and coarse
particulate matter (PM) (e.g., sulfates, nitrates, organic carbon,
elemental carbon, and soil dust) and their precursors (e.g., sulfur
dioxide (SO<INF>2</INF>), nitrogen oxides (NO<INF>X</INF>), and, in
some cases, volatile organic compounds (VOC) and ammonia
(NH<INF>3</INF>)). Fine particle precursors react in the atmosphere to
form fine particulate matter (PM<INF>2.5</INF>), which impairs
visibility by scattering and absorbing light. Visibility impairment
reduces the perception of clarity and color, as well as visible
distance.\5\
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\5\ There are several ways to measure the amount of visibility
impairment, i.e., haze. One such measurement is the deciview, which
is the principal metric used by the RHR. Under many circumstances, a
change in one deciview will be perceived by the human eye to be the
same on both clear and hazy days. The deciview is unitless. It is
proportional to the logarithm of the atmospheric extinction of
light, which is the perceived dimming of light due to its being
scattered and absorbed as it passes through the atmosphere.
Atmospheric light extinction (b\ext\) is a metric used for
expressing visibility and is measured in inverse megameters (Mm\-
1\). The EPA's Guidance on Regional Haze State Implementation Plans
for the Second Implementation Period (``2019 Guidance'') offers the
flexibility for the use of light extinction in certain cases. Light
extinction can be simpler to use in calculations than deciviews,
since it is not a logarithmic function. See, e.g., 2019 Guidance at
16, 19, <a href="https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period">https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period</a>, The EPA Office of
Air Quality Planning and Standards, Research Triangle Park (August
20, 2019). The formula for the deciview is 10 ln (b\ext\)/10 Mm-1).
40 CFR 51.301.
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To address regional haze visibility impairment, the 1999 RHR
established an iterative planning process that requires both states in
which Class I areas are located and states ``the emissions from which
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 such impairment. CAA 169A(b)(2); \6\ see also 40 CFR
51.308(b), (f) (establishing submission dates for iterative regional
haze SIP revisions); (64 FR at 35768, July 1, 1999). 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,'' CAA 169A(b)(2)(B); 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). CAA 169A(b)(2)(A); 40 CFR
51.308(d), (e). States' first regional haze SIPs were due by December
17, 2007, 40 CFR 51.308(b), with subsequent SIP submissions containing
updated long-term strategies originally due July 31, 2018, and every
ten years thereafter. (64 FR at 35768, July 1, 1999). The EPA
established in the 1999 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.\7\ Id. at
35721.
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\6\ The RHR expresses the statutory requirement for states to
submit plans addressing out-of-state Class I areas by providing that
states must address visibility impairment ``in each mandatory Class
I Federal area located outside the State that may be affected by
emissions from within the State.'' 40 CFR 51.308(d), (f).
\7\ In addition to each of the fifty states, the EPA also
concluded that the Virgin Islands and District of Columbia must also
submit regional haze SIPs because they either contain a Class I area
or contain sources whose emissions are reasonably anticipated to
contribute regional haze in a Class I area. See 40 CFR 51.300(b),
(d)(3).
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Much of the focus in the first implementation period of the
regional haze program, which ran from 2007 through 2018, was on
satisfying states' BART obligations. First implementation period SIPs
were additionally required to contain long-term strategies for making
reasonable progress toward the national visibility goal, of which BART
is one component. The core required elements for the first
implementation period SIPs (other than BART) are laid out in 40 CFR
51.308(d). Those provisions required that states containing Class I
areas establish reasonable progress goals (RPGs) that are measured in
deciviews and reflect the anticipated visibility conditions at the end
of the implementation period including from implementation of states'
long-term strategies. The first planning period RPGs were required to
provide for an improvement in visibility for the most impaired days
over the period of the implementation plan and ensure no degradation in
visibility for the least impaired days over the same period. In
establishing the RPGs for any Class I area in a State, the State was
required to consider four statutory factors: the costs of compliance,
the time necessary for compliance, the energy and non-air quality
environmental impacts of compliance, and the remaining useful life of
any potentially affected sources. CAA 169A(g)(1); 40 CFR 51.308(d)(1).
States were also required to calculate baseline (using the five
year period of 2000-2004) and natural visibility conditions (i.e.,
visibility conditions without anthropogenic visibility

[[Page 83340]]

impairment) for each Class I area, and to calculate the linear rate of
progress needed to attain natural visibility conditions, assuming a
starting point of baseline visibility conditions in 2004 and ending
with natural conditions in 2064. This linear interpolation is known as
the uniform rate of progress (URP) and is used as a tracking metric to
help states assess the amount of progress they are making towards the
national visibility goal over time in each Class I area.\8\ 40 CFR
51.308(d)(1)(i)(B), (d)(2). The 1999 RHR also provided that States'
long-term strategies must include the ``enforceable emissions
limitations, compliance, schedules, and other measures as necessary to
achieve the reasonable progress goals.'' 40 CFR 51.308(d)(3). In
establishing their long-term strategies, states are required to consult
with other states that also contribute to visibility impairment in a
given Class I area and include all measures necessary to obtain their
shares of the emission reductions needed to meet the RPGs. 40 CFR
51.308(d)(3)(i), (ii). Section 51.308(d) also contains seven additional
factors states must consider in formulating their long-term strategies,
40 CFR 51.308(d)(3)(v), as well as provisions governing monitoring and
other implementation plan requirements. 40 CFR 51.308(d)(4). Finally,
the 1999 RHR required states to submit periodic progress reports--SIP
revisions due every five years that contain information on states'
implementation of their regional haze plans and an assessment of
whether anything additional is needed to make reasonable progress, see
40 CFR 51.308(g), (h)--and to consult with the Federal Land Manager(s)
\9\ (FLMs) responsible for each Class I area according to the
requirements in CAA 169A(d) and 40 CFR 51.308(i).
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\8\ The EPA established the URP framework in the 1999 RHR to
provide ``an equitable analytical approach'' to assessing the rate
of visibility improvement at Class I areas across the country. The
starting point for the URP analysis is 2004 and the endpoint was
calculated based on the amount of visibility improvement that was
anticipated to result from implementation of existing CAA programs
over the period from the mid-1990s to approximately 2005. Assuming
this rate of progress would continue into the future, the EPA
determined that natural visibility conditions would be reached in 60
years, or 2064 (60 years from the baseline starting point of 2004).
However, the EPA did not establish 2064 as the year by which the
national goal must be reached. 64 FR at 35731-32. That is, the URP
and the 2064 date are not enforceable targets but are rather tools
that ``allow for analytical comparisons between the rate of progress
that would be achieved by the state's chosen set of control measures
and the URP.'' (82 FR 3078, 3084, January 10, 2017).
\9\ The EPA's regulations define ``Federal Land Manager'' as
``the Secretary of the department with authority over the Federal
Class I area (or the Secretary's designee) or, with respect to
Roosevelt-Campobello International Park, the Chairman of the
Roosevelt-Campobello International Park Commission.'' 40 CFR 51.301.
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On January 10, 2017, the EPA promulgated revisions to the RHR, (82
FR 3078, January 10, 2017), that apply for the second and subsequent
implementation periods. The 2017 rulemaking made several changes to the
requirements for regional haze SIPs to clarify States' obligations and
streamline certain regional haze requirements. The revisions to the
regional haze program for the second and subsequent implementation
periods focused on the requirement that States' SIPs contain long-term
strategies for making reasonable progress towards the national
visibility goal. The reasonable progress requirements as revised in the
2017 rulemaking (referred to here as the 2017 RHR Revisions) are
codified at 40 CFR 51.308(f). Among other changes, the 2017 RHR
Revisions adjusted the deadline for States to submit their second
implementation period SIPs from July 31, 2018, to July 31, 2021,
clarified the order of analysis and the relationship between RPGs and
the long-term strategy, and focused on making visibility improvements
on the days with the most anthropogenic visibility impairment, as
opposed to the days with the most visibility impairment overall. The
EPA also revised requirements of the visibility protection program
related to periodic progress reports and FLM consultation. The specific
requirements applicable to second implementation period regional haze
SIP submissions are addressed in detail below.
The EPA provided guidance to the states for their second
implementation period SIP submissions in the preamble to the 2017 RHR
Revisions as well as in subsequent, stand-alone guidance documents. In
August 2019, the EPA issued ``Guidance on Regional Haze State
Implementation Plans for the Second Implementation Period'' (``2019
Guidance'').\10\ On July 8, 2021, the EPA issued a memorandum
containing ``Clarifications Regarding Regional Haze State
Implementation Plans for the Second Implementation Period'' (``2021
Clarifications Memo'').\11\ Additionally, the EPA further clarified the
recommended procedures for processing ambient visibility data and
optionally adjusting the URP to account for international anthropogenic
and prescribed fire impacts in two technical guidance documents: the
December 2018 ``Technical Guidance on Tracking Visibility Progress for
the Second Implementation Period of the Regional Haze Program'' (``2018
Visibility Tracking Guidance''),\12\ and the June 2020 ``Recommendation
for the Use of Patched and Substituted Data and Clarification of Data
Completeness for Tracking Visibility Progress for the Second
Implementation Period of the Regional Haze Program'' and associated
Technical Addendum (``2020 Data Completeness Memo'').\13\
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\10\ Guidance on Regional Haze State Implementation Plans for
the Second Implementation Period. <a href="https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period">https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period</a> The EPA Office of Air Quality Planning and
Standards, Research Triangle Park (August 20, 2019).
\11\ Clarifications Regarding Regional Haze State Implementation
Plans for the Second Implementation Period. <a href="https://www.epa.gov/system/files/documents/2021-07/clarifications-regarding-regional-haze-state-implementation-plans-for-the-second-implementation-period.pdf">https://www.epa.gov/system/files/documents/2021-07/clarifications-regarding-regional-haze-state-implementation-plans-for-the-second-implementation-period.pdf</a>. The EPA Office of Air Quality Planning and Standards,
Research Triangle Park (July 8, 2021).
\12\ Technical Guidance on Tracking Visibility Progress for the
Second Implementation Period of the Regional Haze Program. <a href="https://www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional">https://www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional</a> The EPA Office of Air
Quality Planning and Standards, Research Triangle Park. (December
20, 2018).
\13\ Recommendation for the Use of Patched and Substituted Data
and Clarification of Data Completeness for Tracking Visibility
Progress for the Second Implementation Period of the Regional Haze
Program. <a href="https://www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program">https://www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program</a> The EPA
Office of Air Quality Planning and Standards, Research Triangle Park
(June 3, 2020).
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As explained in the 2021 Clarifications Memo, the EPA intends the
second implementation period of the regional haze program to secure
meaningful reductions in visibility impairing pollutants that build on
the significant progress states have achieved to date. The Agency also
recognizes that analyses regarding reasonable progress are State-
specific and that, based on states' and sources' individual
circumstances, what constitutes reasonable reductions in visibility
impairing pollutants will vary from State-to-State. While there exist
many opportunities for states to leverage both ongoing and upcoming
emission reductions under other CAA programs, the Agency expects states
to undertake rigorous reasonable progress analyses that identify
further opportunities to advance the national visibility goal
consistent with the statutory and regulatory requirements. See
generally 2021 Clarifications Memo. This is consistent with Congress's
determination that a visibility protection program is needed in
addition to the CAA's National Ambient Air Quality Standards and
Prevention of Significant Deterioration programs, as

[[Page 83341]]

further emission reductions may be necessary to adequately protect
visibility in Class I areas throughout the country.\14\
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\14\ See, e.g., H.R. Rep No. 95-294 at 205 (``In determining how
to best remedy the growing visibility problem in these areas of
great scenic importance, the committee realizes that as a matter of
equity, the national ambient air quality standards cannot be revised
to adequately protect visibility in all areas of the country.''),
(``the mandatory class I increments of [the PSD program] do not
adequately protect visibility in class I areas'').
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B. Roles of Agencies in Addressing Regional Haze

Because the air pollutants and pollution affecting visibility in
Class I areas can be transported over long distances, successful
implementation of the regional haze program requires long-term,
regional coordination among multiple jurisdictions and agencies that
have responsibility for Class I areas and the emissions that impact
visibility in those areas. To address regional haze, states need to
develop strategies in coordination with one another, considering the
effect of emissions from one jurisdiction on the air quality in
another. Five regional planning organizations (RPOs),\15\ which include
representation from State and Tribal governments, the EPA, and FLMs,
were developed in the lead-up to the first implementation period to
address regional haze. RPOs evaluate technical information to better
understand how emissions from State and Tribal land impact Class I
areas across the country, pursue the development of regional strategies
to reduce emissions of particulate matter and other pollutants leading
to regional haze, and help states meet the consultation requirements of
the RHR.
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\15\ RPOs are sometimes also referred to as ``multi-
jurisdictional organizations,'' or MJOs. For the purposes of this
notice, the terms RPO and MJO are synonymous.
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The Central Regional Air Planning Association (CenRAP), one of the
five RPOs described above, that Texas was a member of during the first
planning period, was a collaborative effort of State governments,
Tribal governments, and Federal agencies established to initiate and
coordinate activities associated with the management of regional haze,
visibility, and other air quality issues in parts of the Great Plains,
Midwest, Southwest, and South Regions of the United States.
After the first planning period SIPs were submitted, the planning
was shifted to the Central State Air Resources Agencies (CenSARA).
CenSARA was established to promote the exchange of air quality
information, knowledge, experience, and data among and between
participating organizations and other interested parties. It supports
the membership with training and policy and technical projects. CenSARA
supports and promotes collaborative efforts of State governments to
initiate and coordinate activities associated with the management of
regional haze and other air quality issues in parts of the Great
Plains, Midwest, Southwest, and South Regions of the United States.
Member states include: Arkansas, Iowa, Kansas, Louisiana, Missouri,
Nebraska, Oklahoma, and Texas. Unlike CenRAP, CenSARA has solely State
and local government members. However, CenSARA does reach out to Tribal
and Federal partners. The Federal partners of CenSARA are the EPA, the
NPS, the FWS, and FS.

III. Requirements for Regional Haze Plans for the Second Implementation
Period

Under the CAA and EPA's regulations, all 50 States, the District of
Columbia, and the U.S. Virgin Islands are required to submit regional
haze SIPs satisfying the applicable requirements for the second
implementation period of the regional haze program by July 31, 2021.
Each state's SIP must contain a long-term strategy for making
reasonable progress toward meeting the national goal of remedying any
existing and preventing any future anthropogenic visibility impairment
in Class I areas. CAA 169A(b)(2)(B). To this end, Sec. 51.308(f) lays
out the process by which states determine what constitutes their long-
term strategies, with the order of the requirements in Sec.
51.308(f)(1) through (f)(3) generally mirroring the order of the steps
in the reasonable progress analysis \16\ and (f)(4) through (f)(6)
containing additional, related requirements. Broadly speaking, a State
first must identify the Class I areas within the State and determine
the Class I areas outside the State in which visibility may be affected
by emissions from the State. These are the Class I areas that must be
addressed in the state's long-term strategy. See 40 CFR 51.308(f),
(f)(2). For each Class I area within its borders, a State must then
calculate the baseline, current, and natural visibility conditions for
that area, as well as the visibility improvement made to date and the
URP. See 40 CFR 51.308(f)(1). Each State having a Class I area and/or
emissions that may affect visibility in a Class I area must then
develop a long-term strategy that includes the enforceable emission
limitations, compliance schedules, and other measures that are
necessary to make reasonable progress in such areas. A reasonable
progress determination is based on applying the four factors in CAA
section 169A(g)(1) to sources of visibility impairing pollutants that
the State has selected to assess for controls for the second
implementation period. Additionally, as further explained below, the
RHR at 40 CFR 51.3108(f)(2)(iv) separately provides five ``additional
factors'' \17\ that states must consider in developing their long-term
strategies. See 40 CFR 51.308(f)(2). A State evaluates potential
emission reduction measures for those selected sources and determines
which are necessary to make reasonable progress. Those measures are
then incorporated into the state's long-term strategy. After a State
has developed its long-term strategy, it then establishes RPGs for each
Class I area within its borders by modeling the visibility impacts of
all reasonable progress controls at the end of the second
implementation period, i.e., in 2028, as well as the impacts of other
requirements of the CAA. The RPGs include reasonable progress controls
not only for sources in the State in which the Class I area is located,
but also for sources in other states that contribute to visibility
impairment in that area. The RPGs are then compared to the baseline
visibility conditions and the URP to ensure that progress is being made
towards the statutory goal of preventing any future and remedying any
existing anthropogenic visibility impairment in Class I areas. 40 CFR
51.308(f)(2)-(3).
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\16\ The EPA explained in the 2017 RHR Revisions that we were
adopting new regulatory language in 40 CFR 51.308(f) that, unlike
the structure in 51.308(d), ``tracked the actual planning
sequence.'' (82 FR 3091, January 10, 2017).
\17\ The five ``additional factors'' for consideration in
section 51.308(f)(2)(iv) are distinct from the four factors listed
in CAA section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states
must consider and apply to sources in determining reasonable
progress.
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In addition to satisfying the requirements at 40 CFR 51.308(f)
related to reasonable progress, the regional haze SIP revisions for the
second implementation period must address the requirements in Sec.
51.308(g)(1) through (5) pertaining to periodic reports describing
progress towards the RPGs, 40 CFR 51.308(f)(5), as well as requirements
for FLM consultation that apply to all visibility protection SIPs and
SIP revisions. 40 CFR 51.308(i).
A State must submit its regional haze SIP and subsequent SIP
revisions to the EPA according to the requirements applicable to all
SIP revisions under the CAA and EPA's regulations. See CAA 169A(b)(2);
CAA 110(a). Upon EPA approval, a SIP is enforceable by the Agency and
the public under the CAA.

[[Page 83342]]

If EPA finds that a State fails to make a required SIP revision, or if
the EPA finds that a state's SIP is incomplete or disapproves the SIP,
the Agency must promulgate a federal implementation plan (FIP) that
satisfies the applicable requirements. CAA 110(c)(1).

A. Identification of Class I Areas

The first step in developing a regional haze SIP is for a State to
determine which Class I areas, in addition to those within its borders,
``may be affected'' by emissions from within the State. In the 1999
RHR, the EPA determined that all states contribute to visibility
impairment in at least one Class I area, 64 FR at 35720-22, and
explained that the statute and regulations lay out an ``extremely low
triggering threshold'' for determining ``whether States should be
required to engage in air quality planning and analysis as a
prerequisite to determining the need for control of emissions from
sources within their State.'' Id. at 35721.
A State must determine which Class I areas must be addressed by its
SIP by evaluating the total emissions of visibility impairing
pollutants from all sources within the State. While the RHR does not
require this evaluation to be conducted in any particular manner, EPA's
2019 Guidance provides recommendations for how such an assessment might
be accomplished, including by, where appropriate, using the
determinations previously made for the first implementation period.
2019 Guidance at 8-9. In addition, the determination of which Class I
areas may be affected by a state's emissions is subject to the
requirement in 40 CFR 51.308(f)(2)(iii) to ``document the technical
basis, including modeling, monitoring, cost, engineering, and emissions
information, on which the State is relying to determine the emission
reduction measures that are necessary to make reasonable progress in
each mandatory Class I Federal area it affects.''

B. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress

As part of assessing whether a SIP submission for the second
implementation period is providing for reasonable progress towards the
national visibility goal, the RHR contains requirements in Sec.
51.308(f)(1) related to tracking visibility improvement over time. The
requirements of this subsection apply only to states having Class I
areas within their borders; the required calculations must be made for
each such Class I area. EPA's 2018 Visibility Tracking Guidance \18\
provides recommendations to assist states in satisfying their
obligations under Sec. 51.308(f)(1); specifically, in developing
information on baseline, current, and natural visibility conditions,
and in making optional adjustments to the URP to account for the
impacts of international anthropogenic emissions and prescribed fires.
See 82 FR at 3103-05.
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\18\ The 2018 Visibility Tracking Guidance references and relies
on parts of the 2003 Tracking Guidance: ``Guidance for Tracking
Progress Under the Regional Haze Rule,'' which can be found at
<a href="https://www3.epa.gov/ttnamti1/files/ambient/visible/tracking.pdf">https://www3.epa.gov/ttnamti1/files/ambient/visible/tracking.pdf</a>.
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The RHR requires tracking of visibility conditions on two sets of
days: the clearest and the most impaired days. Visibility conditions
for both sets of days are expressed as the average deciview index for
the relevant five-year period (the period representing baseline or
current visibility conditions). The RHR provides that the relevant sets
of days for visibility tracking purposes are the 20% clearest (the 20%
of monitored days in a calendar year with the lowest values of the
deciview index) and 20% most impaired days (the 20% of monitored days
in a calendar year with the highest amounts of anthropogenic visibility
impairment).\19\ 40 CFR 51.301. A State must calculate visibility
conditions for both the 20% clearest and 20% most impaired days for the
baseline period of 2000-2004 and the most recent five-year period for
which visibility monitoring data are available (representing current
visibility conditions). 40 CFR 51.308(f)(1)(i), (iii). States must also
calculate natural visibility conditions for the clearest and most
impaired days,\20\ by estimating the conditions that would exist on
those two sets of days absent anthropogenic visibility impairment. 40
CFR 51.308(f)(1)(ii). Using all these data, states must then calculate,
for each Class I area, the amount of progress made since the baseline
period (2000-2004) and how much improvement is left to achieve to reach
natural visibility conditions.
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\19\ This notice also refers to the 20% clearest and 20% most
anthropogenically impaired days as the ``clearest'' and ``most
impaired'' or ``most anthropogenically impaired'' days,
respectively.
\20\ The RHR at 40 CFR 51.308(f)(1)(ii) contains an error
related to the requirement for calculating two sets of natural
conditions values. The rule says ``most impaired days or the
clearest days'' where it should say ``most impaired days and
clearest days.'' This is an error that was intended to be corrected
in the 2017 RHR Revisions but did not get corrected in the final
rule language. This is supported by the preamble text at 82 FR 3098:
``In the final version of 40 CFR 51.308(f)(1)(ii), an occurrence of
``or'' has been corrected to ``and'' to indicate that natural
visibility conditions for both the most impaired days and the
clearest days must be based on available monitoring information.''
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Using the data for the set of most impaired days only, states must
plot a line between visibility conditions in the baseline period and
natural visibility conditions for each Class I area to determine the
URP--the amount of visibility improvement, measured in deciviews, that
would need to be achieved during each implementation period to achieve
natural visibility conditions by the end of 2064. The URP is used in
later steps of the reasonable progress analysis for informational
purposes and to provide a non-enforceable benchmark against which to
assess a Class I area's rate of visibility improvement.\21\
Additionally, in the 2017 RHR Revisions, the EPA provided states the
option of proposing to adjust the endpoint of the URP to account for
impacts of anthropogenic sources outside the United States and/or
impacts of certain types of wildland prescribed fires. These
adjustments, which must be approved by the EPA, are intended to avoid
any perception that states should compensate for impacts from
international anthropogenic sources and to give states the flexibility
to determine that limiting the use of wildland-prescribed fire is not
necessary for reasonable progress. 82 FR 3107 footnote 116.
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\21\ Being on or below the URP is not a ``safe harbor''; i.e.,
achieving the URP does not mean that a Class I area is making
``reasonable progress'' and does not relieve a state from using the
four statutory factors to determine what level of control is needed
to achieve such progress. See, e.g., 82 FR at 3093.
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The EPA's 2018 Visibility Tracking Guidance can be used to help
satisfy the 40 CFR 51.308(f)(1) requirements, including in developing
information on baseline, current, and natural visibility conditions,
and in making optional adjustments to the URP. In addition, the 2020
Data Completeness Memo provides recommendations on the data
completeness language referenced in Sec. 51.308(f)(1)(i) and provides
updated natural conditions estimates for each Class I area.

C. Long-Term Strategy for Regional Haze

The core component of a regional haze SIP submission is a long-term
strategy that addresses regional haze in each Class I area within a
state's borders and each Class I area that may be affected by emissions
from the State. The long-term strategy ``must include the enforceable
emissions limitations, compliance schedules, and other measures that
are necessary to make reasonable progress, as determined pursuant to
(f)(2)(i) through (iv).'' 40

[[Page 83343]]

CFR 51.308(f)(2). The amount of progress that is ``reasonable
progress'' is based on applying the four statutory factors in CAA
section 169A(g)(1) in an evaluation of potential control options for
sources of visibility impairing pollutants, which is referred to as a
``four-factor'' analysis. The outcome of that analysis is the emission
reduction measures that a particular source or group of sources needs
to implement to make reasonable progress towards the national
visibility goal. See 40 CFR 51.308(f)(2)(i). Emission reduction
measures that are necessary to make reasonable progress may be either
new, additional control measures for a source, or they may be the
existing emission reduction measures that a source is already
implementing. See 2019 Guidance at 43; 2021 Clarifications Memo at 8-
10. Such measures must be represented by ``enforceable emissions
limitations, compliance schedules, and other measures'' (i.e., any
additional compliance tools) in a state's long-term strategy in its
SIP. 40 CFR 51.308(f)(2).
Section 51.308(f)(2)(i) provides the requirements for the four-
factor analysis. The first step of this analysis entails selecting the
sources to be evaluated for emission reduction measures; to this end,
the RHR requires states to consider ``major and minor stationary
sources or groups of sources, mobile sources, and area sources'' of
visibility impairing pollutants for potential four-factor control
analysis. 40 CFR 51.308(f)(2)(i). A threshold question at this step is
which visibility impairing pollutants will be analyzed. As EPA
previously explained, consistent with the first implementation period,
EPA generally expects that each State will analyze at least
SO<INF>2</INF> and NO<INF>X</INF> in selecting sources and determining
control measures. See 2019 Guidance at 12; 2021 Clarifications Memo at
4. A State that chooses not to consider at least these two pollutants
should demonstrate why such consideration would be unreasonable. 2021
Clarifications Memo at 4.
While states have the option to analyze all sources, the 2019
Guidance explains that ``an analysis of control measures is not
required for every source in each implementation period,'' and that
``[s]electing a set of sources for analysis of control measures in each
implementation period is . . . consistent with the Regional Haze Rule,
which sets up an iterative planning process and anticipates that a
State may not need to analyze control measures for all its sources in a
given SIP revision.'' 2019 Guidance at 9. However, given that source
selection is the basis of all subsequent control determinations, a
reasonable source selection process ``should be designed and conducted
to ensure that source selection results in a set of pollutants and
sources the evaluation of which has the potential to meaningfully
reduce their contributions to visibility impairment.'' 2021
Clarifications Memo at 3.
EPA explained in the 2021 Clarifications Memo that each State has
an obligation to submit a long-term strategy that addresses the
regional haze visibility impairment that results from emissions from
within that State. Thus, source selection should focus on the in-state
contribution to visibility impairment and be designed to capture a
meaningful portion of the state's total contribution to visibility
impairment in Class I areas. A State should not decline to select its
largest in-state sources on the basis that there are even larger out-
of-state contributors. 2021 Clarifications Memo at 4.\22\
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\22\ Similarly, in responding to comments on the 2017 RHR
Revisions the EPA explained that ``[a] state should not fail to
address its many relatively low-impact sources merely because it
only has such sources and another state has even more low-impact
sources and/or some high impact sources.'' Responses to Comments on
Protection of Visibility: Amendments to Requirements for State
Plans; Proposed Rule (81 FR 26942, May 4, 2016) at 87-88.
---------------------------------------------------------------------------

Thus, while states have discretion to choose any source selection
methodology that is reasonable, whatever choices they make should be
reasonably explained. To this end, 40 CFR 51.308(f)(2)(i) requires that
a state's SIP submission include ``a description of the criteria it
used to determine which sources or groups of sources it evaluated.''
The technical basis for source selection, which may include methods for
quantifying potential visibility impacts such as emissions divided by
distance metrics, trajectory analyses, residence time analyses, and/or
photochemical modeling, must also be appropriately documented, as
required by 40 CFR 51.308(f)(2)(iii).
Once a State has selected the set of sources, the next step is to
determine the emissions reduction measures for those sources that are
necessary to make reasonable progress for the second implementation
period.\23\ This is accomplished by considering the four factors--``the
costs of compliance, the time necessary for compliance, and the energy
and nonair quality environmental impacts of compliance, and the
remaining useful life of any existing source subject to such
requirements.'' CAA 169A(g)(1). The EPA has explained that the four-
factor analysis is an assessment of potential emission reduction
measures (i.e., control options) for sources; ``use of the terms
`compliance' and `subject to such requirements' in section 169A(g)(1)
strongly indicates that Congress intended the relevant determination to
be the requirements with which sources would have to comply to satisfy
the CAA's reasonable progress mandate.'' 82 FR at 3091. Thus, for each
source it has selected for four-factor analysis,\24\ a State must
consider a ``meaningful set'' of technically feasible control options
for reducing emissions of visibility impairing pollutants. Id. at 3088.
The 2019 Guidance provides that ``[a] State must reasonably pick and
justify the measures that it will consider, recognizing that there is
no statutory or regulatory requirement to consider all technically
feasible measures or any particular measures. A range of technically
feasible measures available to reduce emissions would be one way to
justify a reasonable set.'' 2019 Guidance at 29.
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\23\ The CAA provides that, ``[i]n determining reasonable
progress there shall be taken into consideration'' the four
statutory factors. CAA 169A(g)(1). However, in addition to four-
factor analyses for selected sources, groups of sources, or source
categories, a state may also consider additional emission reduction
measures for inclusion in its long-term strategy, e.g., from other
newly adopted, on-the-books, or on-the-way rules and measures for
sources not selected for four-factor analysis for the second
planning period.
\24\ ``Each source'' or ``particular source'' is used here as
shorthand. While a source-specific analysis is one way of applying
the four factors, neither the statute nor the RHR requires states to
evaluate individual sources. Rather, states have ``the flexibility
to conduct four-factor analyses for specific sources, groups of
sources or even entire source categories, depending on state policy
preferences and the specific circumstances of each state.'' 82 FR at
3088. However, not all approaches to grouping sources for four-
factor analysis are necessarily reasonable; the reasonableness of
grouping sources in any particular instance will depend on the
circumstances and the manner in which grouping is conducted. If it
is feasible to establish and enforce different requirements for
sources or subgroups of sources, and if relevant factors can be
quantified for those sources or subgroups, then states should make a
separate reasonable progress determination for each source or
subgroup. 2021 Clarifications Memo at 7-8.
---------------------------------------------------------------------------

EPA's 2021 Clarifications Memo provides further guidance on what
constitutes a reasonable set of control options for consideration: ``A
reasonable four-factor analysis will consider the full range of
potentially reasonable options for reducing emissions.'' 2021
Clarifications Memo at 7. In addition to add-on controls and other
retrofits (i.e., new emissions reduction measures for sources), EPA
explained that states should generally analyze efficiency improvements
for sources' existing measures as control options in their four-factor
analyses, as in many cases such improvements are reasonable given that
they typically involve only additional operation and maintenance

[[Page 83344]]

costs. Additionally, the 2021 Clarifications Memo provides that states
that have assumed a higher emissions rate than a source has achieved or
could potentially achieve using its existing measures should also
consider lower emissions rates as potential control options. That is, a
State should consider a source's recent actual and projected emission
rates to determine if it could reasonably attain lower emission rates
with its existing measures. If so, the State should analyze the lower
emission rate as a control option for reducing emissions. 2021
Clarifications Memo at 7. The EPA's recommendations to analyze
potential efficiency improvements and achievable lower emission rates
apply to both sources that have been selected for four-factor analysis
and those that have forgone a four-factor analysis on the basis of
existing ``effective controls.'' See 2021 Clarifications Memo at 5, 10.
After identifying a reasonable set of potential control options for
the sources it has selected, a State then collects information on the
four factors with regard to each option identified. The EPA has also
explained that, in addition to the four statutory factors, states have
flexibility under the CAA and RHR to reasonably consider visibility
benefits as an additional factor alongside the four statutory
factors.\25\ The 2019 Guidance provides recommendations for the types
of information that can be used to characterize the four factors (with
or without visibility), as well as ways in which states might
reasonably consider and balance that information to determine which of
the potential control options is necessary to make reasonable progress.
See 2019 Guidance at 30-36. The 2021 Clarifications Memo contains
further guidance on how states can reasonably consider modeled
visibility impacts or benefits in the context of a four-factor
analysis. 2021 Clarifications Memo at 12-13, 14-15. Specifically, the
EPA explained that while visibility can reasonably be used when
comparing and choosing between multiple reasonable control options, it
should not be used to summarily reject controls that are reasonable
given the four statutory factors. 2021 Clarifications Memo at 13.
Ultimately, while states have discretion to reasonably weigh the
factors and to determine what level of control is needed, Sec.
51.308(f)(2)(i) provides that a State ``must include in its
implementation plan a description of . . . how the four factors were
taken into consideration in selecting the measure for inclusion in its
long-term strategy.''
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\25\ See, e.g., Responses to Comments on Protection of
Visibility: Amendments to Requirements for State Plans; Proposed
Rule (81 FR 26942, May 4, 2016) (December 2016), Docket Number EPA-
HQ-OAR-2015-0531, U.S. Environmental Protection Agency at 186; 2019
Guidance at 36-37.
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As explained above, Sec. 51.308(f)(2)(i) requires states to
determine the emission reduction measures for sources that are
necessary to make reasonable progress by considering the four factors.
Pursuant to Sec. 51.308(f)(2), measures that are necessary to make
reasonable progress towards the national visibility goal must be
included in a state's long-term strategy and in its SIP.\26\ If the
outcome of a four-factor analysis is a new, additional emission
reduction measure for a source, that new measure is necessary to make
reasonable progress towards remedying existing anthropogenic visibility
impairment and must be included in the SIP. If the outcome of a four-
factor analysis is that no new measures are reasonable for a source,
continued implementation of the source's existing measures is generally
necessary to prevent future emission increases and thus to make
reasonable progress towards the second part of the national visibility
goal: preventing future anthropogenic visibility impairment. See CAA
169A(a)(1). That is, when the result of a four-factor analysis is that
no new measures are necessary to make reasonable progress, the source's
existing measures are generally necessary to make reasonable progress
and must be included in the SIP. However, there may be circumstances in
which a State can demonstrate that a source's existing measures are not
necessary to make reasonable progress. Specifically, if a State can
demonstrate that a source will continue to implement its existing
measures and will not increase its emissions rate, it may not be
necessary to have those measures in the long-term strategy to prevent
future emissions increases and future visibility impairment. The EPA's
2021 Clarifications Memo provides further explanation and guidance on
how states may demonstrate that a source's existing measures are not
necessary to make reasonable progress. See 2021 Clarifications Memo at
8-10. If the State can make such a demonstration, it need not include a
source's existing measures in the long-term strategy or its SIP.
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\26\ States may choose to, but are not required to, include
measures in their long-term strategies beyond just the emission
reduction measures that are necessary for reasonable progress. See
2021 Clarifications Memo at 16. For example, states with smoke
management programs may choose to submit their smoke management
plans to the EPA for inclusion in their SIPs but are not required to
do so. See, e.g., 82 FR at 3108-09 (requirement to consider smoke
management practices and smoke management programs under 40 CFR
51.308(f)(2)(iv) does not require states to adopt such practices or
programs into their SIPs, although they may elect to do so).
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As with source selection, the characterization of information on
each of the factors is also subject to the documentation requirement in
Sec. 51.308(f)(2)(iii). The reasonable progress analysis, including
source selection, information gathering, characterization of the four
statutory factors (and potentially visibility), balancing of the four
factors, and selection of the emission reduction measures that
represent reasonable progress, is a technically complex exercise, but
also a flexible one that provides states with bounded discretion to
design and implement approaches appropriate to their circumstances.
Given this flexibility, Sec. 51.308(f)(2)(iii) plays an important
function in requiring a State to document the technical basis for its
decision making so that the public and the EPA can comprehend and
evaluate the information and analysis the State relied upon to
determine what emission reduction measures must be in place to make
reasonable progress. The technical documentation must include the
modeling, monitoring, cost, engineering, and emissions information on
which the State relied to determine the measures necessary to make
reasonable progress. This documentation requirement can be met through
the provision of and reliance on technical analyses developed through a
regional planning process, so long as that process and its output has
been approved by all State participants. In addition to the explicit
regulatory requirement to document the technical basis of their
reasonable progress determinations, states are also subject to the
general principle that those determinations must be reasonably moored
to the statute.\27\ That is, a state's decisions about the emission
reduction measures that are necessary to make reasonable progress must
be consistent with the statutory goal of remedying existing and
preventing future visibility impairment.
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\27\ See Arizona ex rel. Darwin v. U.S. EPA, 815 F.3d 519, 531
(9th Cir. 2016); Nebraska v. U.S. EPA, 812 F.3d 662, 668 (8th Cir.
2016); North Dakota v. EPA, 730 F.3d 750, 761 (8th Cir. 2013);
Oklahoma v. EPA, 723 F.3d 1201, 1206, 1208-10 (10th Cir. 2013); cf.
also Nat'l Parks Conservation Ass'n v. EPA, 803 F.3d 151, 165 (3d
Cir. 2015); Alaska Dep't of Envtl. Conservation v. EPA, 540 U.S.
461, 485, 490 (2004).
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The four statutory factors (and potentially visibility) are used to
determine what emission reduction measures for selected sources must be
included in a state's long-term strategy

[[Page 83345]]

for making reasonable progress. Additionally, the RHR at 40 CFR
51.3108(f)(2)(iv) separately provides five ``additional factors'' \28\
that states must consider in developing their long-term strategies: (1)
Emission reductions due to ongoing air pollution control programs,
including measures to address reasonably attributable visibility
impairment; (2) measures to reduce the impacts of construction
activities; (3) source retirement and replacement schedules; (4) basic
smoke management practices for prescribed fire used for agricultural
and wildland vegetation management purposes and smoke management
programs; and (5) the anticipated net effect on visibility due to
projected changes in point, area, and mobile source emissions over the
period addressed by the long-term strategy. The 2019 Guidance provides
that a State may satisfy this requirement by considering these
additional factors in the process of selecting sources for four-factor
analysis, when performing that analysis, or both, and that not every
one of the additional factors needs to be considered at the same stage
of the process. See 2019 Guidance at 21. The EPA provided further
guidance on the five additional factors in the 2021 Clarifications
Memo, explaining that a State should generally not reject cost-
effective and otherwise reasonable controls merely because there have
been emission reductions since the first planning period owing to other
ongoing air pollution control programs or merely because visibility is
otherwise projected to improve at Class I areas. Additionally, states
generally should not rely on these additional factors to summarily
assert that the State has already made sufficient progress and,
therefore, no sources need to be selected or no new controls are needed
regardless of the outcome of four-factor analyses. 2021 Clarifications
Memo at 13.
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\28\ The five ``additional factors'' for consideration in
section 51.308(f)(2)(iv) are distinct from the four factors listed
in CAA section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states
must consider and apply to sources in determining reasonable
progress.
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Because the air pollution that causes regional haze crosses State
boundaries, Sec. 51.308(f)(2)(ii) requires a State to consult with
other states that also have emissions that are reasonably anticipated
to contribute to visibility impairment in a given Class I area.
Consultation allows for each State that impacts visibility in an area
to share whatever technical information, analyses, and control
determinations may be necessary to develop coordinated emission
management strategies. This coordination may be managed through inter-
and intra-RPO consultation and the development of regional emissions
strategies; additional consultations between states outside of RPO
processes may also occur. If a State, pursuant to consultation, agrees
that certain measures (e.g., a certain emission limitation) are
necessary to make reasonable progress at a Class I area, it must
include those measures in its SIP. 40 CFR 51.308(f)(2)(ii)(A).
Additionally, the RHR requires that states that contribute to
visibility impairment at the same Class I area consider the emission
reduction measures the other contributing states have identified as
being necessary to make reasonable progress for their own sources. 40
CFR 51.308(f)(2)(ii)(B). If a State has been asked to consider or adopt
certain emission reduction measures, but ultimately determines those
measures are not necessary to make reasonable progress, that State must
document in its SIP the actions taken to resolve the disagreement. 40
CFR 51.308(f)(2)(ii)(C). The EPA will consider the technical
information and explanations presented by the submitting State and the
State with which it disagrees when considering whether to approve the
state's SIP. See Id.; 2019 Guidance at 53. Under all circumstances, a
State must document in its SIP submission all substantive consultations
with other contributing states. 40 CFR 51.308(f)(2)(ii)(C).

D. Reasonable Progress Goals

Reasonable progress goals ``measure the progress that is projected
to be achieved by the control measures states have determined are
necessary to make reasonable progress based on a four-factor
analysis.'' 82 FR at 3091. Their primary purpose is to assist the
public and the EPA in assessing the reasonableness of states' long-term
strategies for making reasonable progress towards the national
visibility goal. See 40 CFR 51.308(f)(3)(iii)-(iv). States in which
Class I areas are located must establish two RPGs, both in deciviews--
one representing visibility conditions on the clearest days and one
representing visibility on the most anthropogenically impaired days--
for each area within their borders. 40 CFR 51.308(f)(3)(i). The two
RPGs are intended to reflect the projected impacts, on the two sets of
days, of the emission reduction measures the State with the Class I
area, as well as all other contributing states, have included in their
long-term strategies for the second implementation period.\29\ The RPGs
also account for the projected impacts of implementing other CAA
requirements, including non-SIP based requirements. Because RPGs are
the modeled result of the measures in states' long-term strategies (as
well as other measures required under the CAA), they cannot be
determined before states have conducted their four-factor analyses and
determined the control measures that are necessary to make reasonable
progress. See 2021 Clarifications Memo at 6.
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\29\ RPGs are intended to reflect the projected impacts of the
measures all contributing states include in their long-term
strategies. However, due to the timing of analyses and of control
determinations by other states, other on-going emissions changes, a
particular state's RPGs may not reflect all control measures and
emissions reductions that are expected to occur by the end of the
implementation period. The 2019 Guidance provides recommendations
for addressing the timing of RPG calculations when states are
developing their long-term strategies on disparate schedules, as
well as for adjusting RPGs using a post-modeling approach. 2019
Guidance at 47-48.
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For the second implementation period, the RPGs are set for 2028.
Reasonable progress goals are not enforceable targets, 40 CFR
51.308(f)(3)(iii); rather, they ``provide a way for the states to check
the projected outcome of the [long-term strategy] against the goals for
visibility improvement.'' 2019 Guidance at 46. While states are not
legally obligated to achieve the visibility conditions described in
their RPGs, Sec. 51.308(f)(3)(i) requires that ``[t]he long-term
strategy and the reasonable progress goals must provide for an
improvement in visibility for the most impaired days since the baseline
period and ensure no degradation in visibility for the clearest days
since the baseline period.'' Thus, states are required to have emission
reduction measures in their long-term strategies that are projected to
achieve visibility conditions on the most impaired days that are better
than the baseline period and shows no degradation on the clearest days
compared to the clearest days from the baseline period. The baseline
period for the purpose of this comparison is the baseline visibility
condition--the annual average visibility condition for the period 2000-
2004. See 40 CFR 51.308(f)(1)(i), 82 FR at 3097-98.
So that RPGs may also serve as a metric for assessing the amount of
progress a State is making towards the national visibility goal, the
RHR requires states with Class I areas to compare the 2028 RPG for the
most impaired days to the corresponding point on the URP line
(representing visibility conditions in 2028 if visibility

[[Page 83346]]

were to improve at a linear rate from conditions in the baseline period
of 2000-2004 to natural visibility conditions in 2064). If the most
impaired days RPG in 2028 is above the URP (i.e., if visibility
conditions are improving more slowly than the rate described by the
URP), each State that contributes to visibility impairment in the Class
I area must demonstrate, based on the four-factor analysis required
under 40 CFR 51.308(f)(2)(i), that no additional emission reduction
measures would be reasonable to include in its long-term strategy. 40
CFR 51.308(f)(3)(ii). To this end, 40 CFR 51.308(f)(3)(ii) requires
that each State contributing to visibility impairment in a Class I area
that is projected to improve more slowly than the URP provide ``a
robust demonstration, including documenting the criteria used to
determine which sources or groups [of] sources were evaluated and how
the four factors required by paragraph (f)(2)(i) were taken into
consideration in selecting the measures for inclusion in its long-term
strategy.'' The 2019 Guidance provides suggestions about how such a
``robust demonstration'' might be conducted. See 2019 Guidance at 50-
51.
The 2017 RHR, 2019 Guidance, and 2021 Clarifications Memo also
explain that projecting an RPG that is on or below the URP based on
only on-the-books and/or on-the-way control measures (i.e., control
measures already required or anticipated before the four-factor
analysis is conducted) is not a ``safe harbor'' from the CAA's and
RHR's requirement that all states must conduct a four-factor analysis
to determine what emission reduction measures constitute reasonable
progress. The URP is a planning metric used to gauge the amount of
progress made thus far and the amount left before reaching natural
visibility conditions. However, the URP is not based on consideration
of the four statutory factors and therefore cannot answer the question
of whether the amount of progress being made in any particular
implementation period is ``reasonable progress.'' See 82 FR at 3093,
3099-3100; 2019 Guidance at 22; 2021 Clarifications Memo at 15-16.

E. Monitoring Strategy and Other State Implementation Plan Requirements

Section 51.308(f)(6) requires states to have certain strategies and
elements in place for assessing and reporting on visibility. Individual
requirements under this subsection apply either to states with Class I
areas within their borders, states with no Class I areas but that are
reasonably anticipated to cause or contribute to visibility impairment
in any Class I area, or both. A State with Class I areas within its
borders must submit with its SIP revision a monitoring strategy for
measuring, characterizing, and reporting regional haze visibility
impairment that is representative of all Class I areas within the
State. SIP revisions for such states must also provide for the
establishment of any additional monitoring sites or equipment needed to
assess visibility conditions in Class I areas, as well as reporting of
all visibility monitoring data to the EPA at least annually. Compliance
with the monitoring strategy requirement may be met through a state's
participation in the Interagency Monitoring of Protected Visual
Environments (IMPROVE) monitoring network, which is used to measure
visibility impairment caused by air pollution at the 156 Class I areas
covered by the visibility program. 40 CFR 51.308(f)(6), (f)(6)(i),
(f)(6)(iv). The IMPROVE monitoring data is used to determine the 20%
most anthropogenically impaired and 20% clearest sets of days every
year at each Class I area and tracks visibility impairment over time.
All states' SIPs must provide for procedures by which monitoring
data and other information are used to determine the contribution of
emissions from within the State to regional haze visibility impairment
in affected Class I areas. 40 CFR 51.308(f)(6)(ii), (iii). Section
51.308(f)(6)(v) further requires that all states' SIPs provide for a
statewide inventory of emissions of pollutants that are reasonably
anticipated to cause or contribute to visibility impairment in any
Class I area; the inventory must include emissions for the most recent
year for which data are available and estimates of future projected
emissions. States must also include commitments to update their
inventories periodically. The inventories themselves do not need to be
included as elements in the SIP and are not subject to EPA review as
part of the Agency's evaluation of a SIP revision.\30\ All states' SIPs
must also provide for any other elements, including reporting,
recordkeeping, and other measures, that are necessary for states to
assess and report on visibility. 40 CFR 51.308(f)(6)(vi). Per the 2019
Guidance, a State may note in its regional haze SIP that its compliance
with the Air Emissions Reporting Rule (AERR) in 40 CFR part 51 subpart
A satisfies the requirement to provide for an emissions inventory for
the most recent year for which data are available. To satisfy the
requirement to provide estimates of future projected emissions, a State
may explain in its SIP how projected emissions were developed for use
in establishing RPGs for its own and nearby Class I areas.\31\
---------------------------------------------------------------------------

\30\ See ``Step 8: Additional requirements for regional haze
SIPs'' in 2019 Guidance at 55.
\31\ Id.
---------------------------------------------------------------------------

Separate from the requirements related to monitoring for regional
haze purposes under 40 CFR 51.308(f)(6), the RHR also contains a
requirement at Sec. 51.308(f)(4) related to any additional monitoring
that may be needed to address visibility impairment in Class I areas
from a single source or a small group of sources. This is called
``reasonably attributable visibility impairment.'' \32\ Under this
provision, if the EPA or the FLM of an affected Class I area has
advised a State that additional monitoring is needed to assess
reasonably attributable visibility impairment, the State must include
in its SIP revision for the second implementation period an appropriate
strategy for evaluating such impairment.
---------------------------------------------------------------------------

\32\ The EPA's visibility protection regulations define
``reasonably attributable visibility impairment'' as ``visibility
impairment that is caused by the emission of air pollutants from
one, or a small number of sources.'' 40 CFR 51.301.
---------------------------------------------------------------------------

F. Requirements for Periodic Reports Describing Progress Towards the
Reasonable Progress Goals

Section 51.308(f)(5) requires a state's regional haze SIP revision
to address the requirements of paragraphs 40 CFR 51.308(g)(1) through
(5) so that the plan revision due in 2021 will serve also as a progress
report addressing the period since submission of the progress report
for the first implementation period. The regional haze progress report
requirement is designed to inform the public and the EPA about a
state's implementation of its existing long-term strategy and whether
such implementation is in fact resulting in the expected visibility
improvement. See 81 FR 26942, 26950 (May 4, 2016); 82 FR at 3119
(January 10, 2017). To this end, every state's SIP revision for the
second implementation period is required to describe the status of
implementation of all measures included in the state's long-term
strategy, including BART and reasonable progress emission reduction
measures from the first implementation period, and the resulting
emissions reductions. 40 CFR 51.308(g)(1) and (2).

[[Page 83347]]

A core component of the progress report requirements is an
assessment of changes in visibility conditions on the clearest and most
impaired days. For second implementation period progress reports, Sec.
51.308(g)(3) requires states with Class I areas within their borders to
first determine current visibility conditions for each area on the most
impaired and clearest days, 40 CFR 51.308(g)(3)(i)(B), and then to
calculate the difference between those current conditions and baseline
(2000-2004) visibility conditions to assess progress made to date. See
40 CFR 51.308(g)(3)(ii)(B). States must also assess the changes in
visibility impairment for the most impaired and clearest days since
they submitted their first implementation period progress reports. See
40 CFR 51.308(g)(3)(iii)(B), (f)(5). Since different states submitted
their first implementation period progress reports at different times,
the starting point for this assessment will vary State by State.
Similarly, states must provide analyses tracking the change in
emissions of pollutants contributing to visibility impairment from all
sources and activities within the State over the period since they
submitted their first implementation period progress reports. See 40
CFR 51.308(g)(4), (f)(5). Changes in emissions should be identified by
the type of source or activity. Section 51.308(g)(5) also addresses
changes in emissions since the period addressed by the previous
progress report and requires states' SIP revisions to include an
assessment of any significant changes in anthropogenic emissions within
or outside the State. This assessment must explain whether these
changes in emissions were anticipated and whether they have limited or
impeded progress in reducing emissions and improving visibility
relative to what the State projected based on its long-term strategy
for the first implementation period.

G. Requirements for State and Federal Land Manager Coordination

Clean Air Act section 169A(d) requires that before a State holds a
public hearing on a proposed regional haze SIP revision, it must
consult with the appropriate FLM or FLMs; pursuant to that
consultation, the State must include a summary of the FLMs' conclusions
and recommendations in the notice to the public. Consistent with this
statutory requirement, the RHR also requires that states ``provide the
[FLM] with an opportunity for consultation, in person and at a point
early enough in the State's policy analyses of its long-term strategy
emission reduction obligation so that information and recommendations
provided by the [FLM] can meaningfully inform the State's decisions on
the long-term strategy.'' 40 CFR 51.308(i)(2). Consultation that occurs
120 days prior to any public hearing or public comment opportunity will
be deemed ``early enough,'' but the RHR provides that in any event the
opportunity for consultation must be provided at least 60 days before a
public hearing or comment opportunity. This consultation must include
the opportunity for the FLMs to discuss their assessment of visibility
impairment in any Class I area and their recommendations on the
development and implementation of strategies to address such
impairment. 40 CFR 51.308(i)(2). For the EPA to evaluate whether FLM
consultation meeting the requirements of the RHR has occurred, the SIP
submission should include documentation of the timing and content of
such consultation. The SIP revision submitted to the EPA must also
describe how the State addressed any comments provided by the FLMs. 40
CFR 51.308(i)(3). Finally, a SIP revision must provide procedures for
continuing consultation between the State and FLMs regarding the
state's visibility protection program, including development and review
of SIP revisions, five-year progress reports, and the implementation of
other programs having the potential to contribute to impairment of
visibility in Class I areas. 40 CFR 51.308(i)(4).

IV. The EPA's Evaluation of Texas's Regional Haze Submission for the
Second Implementation Period

A. Background on Texas's First Implementation Period SIP Submission

Texas submitted its regional haze SIP for the first implementation
period to the EPA on March 31, 2009. The EPA issued a limited
disapproval of Texas's RH SIP on June 7, 2012, due to its reliance on
the Clean Air Interstate Rule (CAIR) to address BART requirements for
Texas electric generating units (EGUs).\33\ The EPA proposed a rule to
partially approve and partially disapprove Texas's SIP on December 16,
2014; \34\ however, due to a related ruling from the United States
Court of Appeals for the District of Columbia Circuit (D.C.
Circuit),\35\ the EPA could not finalize the December 2014 proposal in
its entirety. As such, the EPA's obligations for the first
implementation period for Texas's regional haze SIP were addressed in
two separate actions. One action, finalized on January 5, 2016,
addressed the regional haze requirements in Texas except for BART
requirements for EGUs.\36\ The second action, finalized on October 17,
2017, and affirmed on August 12, 2020, addressed BART requirements for
Texas EGUs.\37\ The EPA has convened separate reconsideration
proceedings for both actions.\38\ While these proceedings remain
ongoing, they do not interfere with the EPA's statutory obligation to
take action on Texas's SIP revision for the second implementation
period.\39\
---------------------------------------------------------------------------

\33\ 77 FR 33642 (June 7, 2012).
\34\ 79 FR 74818 (Dec. 16, 2014).
\35\ EME Homer City Generation, L.P v. EPA, 795 F.3d 118 (D.C.
Cir. 2015).
\36\ 81 FR 296 (Jan. 5, 2016). In July 2016, the 5th Circuit
Court of Appeals issued a stay of the action. Texas v. EPA, 829 F.3d
405 (5th Cir. 2016). Subsequent to the stay opinion, the EPA
requested and the court granted EPA's motion for a partial voluntary
remand.
\37\ See 82 FR 48324 (Oct. 17, 2017); 85 FR 49170 (Aug. 12,
2020).
\38\ See 88 FR 28918 (May 4, 2023); 88 FR 48152 (July 26, 2023).
\39\ EPA is not precluded from acting on a submitted second
planning period SIP revision because reconsideration proceedings on
first planning period actions remains ongoing. All states had an
obligation to submit second planning period SIP revisions by July
31, 2021, regardless of the status of first planning period
obligations. After a second planning period SIP revision is
submitted to EPA for review, EPA is statutorily required to review
and act on that plan within 12 months of the submittal being deemed
complete. See CAA 110(k)(1); 42 U.S.C. 7410(k)(1). Even with ongoing
work on the second planning period, EPA will continue to work to
address first planning period obligations.
---------------------------------------------------------------------------

The requirements for regional haze SIPs for the first
implementation period are contained in 40 CFR 51.308(d) and (e).
Pursuant to 40 CFR 51.308(g), Texas was also responsible for submitting
a five-year progress report as a SIP revision for the first
implementation period, which it did in 2014.\40\
---------------------------------------------------------------------------

\40\ The EPA has not yet taken action on the progress report
SIP.
---------------------------------------------------------------------------

B. Texas's Second Implementation Period SIP Submission and the EPA's
Evaluation

In accordance with CAA sections 169A and the RHR at 40 CFR
51.308(f) and (i), on July 20, 2021, Texas submitted a SIP revision to
address its regional haze obligations for the second implementation
period, which runs through 2028. Texas made its 2021 Regional Haze SIP
submission available for public comment on October 9, 2020. Texas
received and responded to public comments and included the comments and
responses to those comments in their submission.
The following sections describe Texas's RH SIP submission, Texas's
assessment of progress made since the first implementation period in
reducing emissions of visibility impairing pollutants, and the
visibility improvement progress at its Class I areas

[[Page 83348]]

and nearby Class I areas. This notice also contains EPA's evaluation of
Texas's submission against the requirements of the CAA and RHR for the
second implementation period of the regional haze program.

C. Identification of Class I Areas

Section 169A(b)(2) of the CAA requires each State in which any
Class I area is located or ``the emissions from which may reasonably be
anticipated to cause or contribute to any impairment of visibility'' in
a Class I area to have a plan for making reasonable progress toward the
national visibility goal. The RHR implements this statutory requirement
at 40 CFR 51.308(f), which provides that each state's plan ``must
address regional haze in each mandatory Class I Federal area located
within the State and in each mandatory Class I Federal area located
outside the State that may be affected by emissions from within the
State,'' and (f)(2), which requires each state's plan to include a
long-term strategy that addresses regional haze in such Class I areas.
The EPA explained in the 1999 RHR preamble that the CAA section
169A(b)(2) requirement that states submit SIPs to address visibility
impairment establishes ``an `extremely low triggering threshold' in
determining which States should submit SIPs for regional haze.'' \41\
In concluding that each of the contiguous 48 States and the District of
Columbia meet this threshold,\42\ the EPA relied on ``a large body of
evidence demonstrat[ing] that long-range transport of fine PM
contributes to regional haze,'' \43\ including modeling studies that
``preliminarily demonstrated that each State not having a Class I area
had emissions contributing to impairment in at least one downwind Class
I area.'' \44\ In addition to the technical evidence supporting a
conclusion that each State contributes to existing visibility
impairment, the EPA also explained that the second half of the national
visibility goal--preventing future visibility impairment--requires
having a framework in place to address future growth in visibility
impairing emissions and makes it inappropriate to ``establish criteria
for excluding States or geographic areas from consideration as
potential contributors to regional haze visibility impairment.'' \45\
Thus, the EPA concluded that the agency's ``statutory authority and the
scientific evidence are sufficient to require all States to develop
regional haze SIPs to ensure the prevention of any future impairment of
visibility, and to conduct further analyses to determine whether
additional control measures are needed to ensure reasonable progress in
remedying existing impairment in downwind Class I areas.'' \46\ The
EPA's 2017 revisions to the RHR did not disturb this conclusion.\47\
---------------------------------------------------------------------------

\41\ 64 FR at 35721.
\42\ The EPA determined that ``there is more than sufficient
evidence to support our conclusion that emissions from each of the
48 contiguous States may reasonably be anticipated to cause or
contribute to visibility impairment in a Class I area.'' 64 FR at
35721. Hawaii, Alaska, and the U.S. Virgin Islands must also submit
regional haze SIPs because they contain Class I areas.
\43\ Id.
\44\ Id. at 35722.
\45\ Id. at 35721.
\46\ Id. at 35722.
\47\ See 82 FR at 3094.
---------------------------------------------------------------------------

1. Texas Class I Areas
Texas has two mandatory Class I areas within its borders, both of
which are located in west Texas. Big Bend National Park (Big Bend) is
in Brewster County and borders the Rio Grande and Mexico. Guadalupe
Mountains National Park (Guadalupe Mountains) is in Culberson County
and borders New Mexico. Both are managed by the National Park Service.
Big Bend was authorized as a national park on June 20, 1935, and
established and signed into law on June 12, 1944, as the nation's 27th
national park. Big Bend encompasses an area of 801,163 acres, entirely
within Brewster County, Texas. For more than 1,000 miles, the Rio
Grande forms the boundary between Mexico and the U.S., with Big Bend
administering approximately 118 miles along the international boundary.
The park gets its name from the course of the Rio Grande, which makes a
great bend from a southeasterly to northerly direction in the western
portion of Texas. Big Bend has national significance as the largest
protected area of Chihuahuan Desert in the continental U.S. The park
contains river, desert, and mountain environments.
Guadalupe Mountains was established as a national park on September
30, 1972, and contains Guadalupe Peak, the highest point in Texas at
8,749 feet, and El Capitan, a 1,000 foot-high limestone cliff.
Guadalupe Mountains are also part of a mostly buried 400-mile long U-
shaped fossil reef complex, Capitan Reef. The park covers more than
86,000 acres and is in the same mountain range of Carlsbad Caverns
National Park, which is located about 40 miles to the northeast in New
Mexico. Guadalupe Mountains is also located in the Chihuahuan Desert.
The park is surrounded by the South Plains to the east and north,
Delaware Mountains to the south, and Sacramento Mountains to the west.
2. Identification of Impacted Class I Areas Outside the State
In addition to the two Class I areas in Texas, the TCEQ conducted
area of influence analyses (AOIs) paired with emissions-over-distance
(Q/d) analyses for 11 Class I areas in other states including
Louisiana, Arkansas, Colorado, Missouri, Oklahoma, and New Mexico. The
AOIs were generated using ammonium sulfate and ammonium nitrate
extinction-weighted residence times (EWRT).\48\ The Class I areas
included in the analysis from Texas and neighboring states are
presented in table 1, which is taken from table 7-3: Class I Areas
included in AOI Analyses of the 2021 Texas Regional Haze Plan.\49\
---------------------------------------------------------------------------

\48\ 2021 Texas Regional Haze Plan at 7-6. Extinction-weighted
residence time is calculated from the time that a particular back-
trajectory from a Class I area spent in the grid square containing
the individual emission source of interest (residence time) weighted
by the extinction coefficient for the visibility precursor (sulfate
and nitrate).
\49\ For the purposes of the AOI analysis, Carlsbad Caverns was
represented by data from the Guadalupe Mountains National Park
monitor. See 2021 Texas Regional Haze Plan at 1-5.

Table 1--Class I Areas Included in AOI Analyses of the 2021 Texas Regional Haze Plan
----------------------------------------------------------------------------------------------------------------
Site Code State County Latitude Longitude
----------------------------------------------------------------------------------------------------------------
Big Bend National Park............ BIBE1................ TX 48043 29.3027 -103.178
Breton Island..................... BRIS1................ LA 22075 30.10863 -89.76168
Caney Creek....................... CACR1................ AR 05113 34.4544 -94.1429
Great Sand Dunes.................. GRSA1................ CO 08003 37.7249 -105.5185
Guadalupe Mountains National Park. GUMO................. TX 48109 31.833 -104.8094
Hercules-Glades................... HEG1................. MO 29213 36.6138 -92.9221
Mingo............................. MING1................ MO 29207 36.9717 -90.1432

[[Page 83349]]

Rocky Mountain National Park...... ROMO1................ CO 08069 40.2783 -105.5457
Salt Creek........................ SACR1................ NM 35005 33.4598 -104.4042
Upper Buffalo Wilderness.......... UPBO1................ AR 05101 35.8258 -93.203
Wheeler Peak...................... WHPE1................ NM 35055 36.5854 -105.42
White Mountain.................... WHIT1................ NM 35027 33.4687 -105.5349
Wichita Mountains................. WIMO1................ OK 40031 34.7323 -98.713
----------------------------------------------------------------------------------------------------------------

As explained above, the EPA concluded in the 1999 RHR that ``all
[s]tates contain sources whose emissions are reasonably anticipated to
contribute to regional haze in a Class I area,'' and this determination
was not changed in the 2017 RHR.\50\ Critically, the statute and
regulation both require that the cause-or-contribute assessment
consider all emissions of visibility impairing pollutants from a State,
as opposed to emissions of a particular pollutant or emissions from a
certain set of sources. Consistent with these requirements, the 2019
Guidance makes it clear that ``all types of anthropogenic sources are
to be included in the determination'' of whether a state's emissions
are reasonably anticipated to result in any visibility impairment.\51\
---------------------------------------------------------------------------

\50\ 64 FR at 35721.
\51\ 2019 Guidance at 8.
---------------------------------------------------------------------------

While Texas identified Class I areas within and outside of the
State that are potentially impacted by Texas sources, Texas did not
conduct an AOI analysis for the Bosque del Apache Class I area.\52\
Texas justifies this decision based on ``past SIP and FIP
documentation'' but provides no additional context or explanation of
why that decision remains appropriate for this planning period.\53\ In
contrast, Texas's CAMx PSAT \54\ modeling identified Bosque del Apache
as having impacts from Texas sources. According to Texas's PSAT
modeling, Texas sources contribute over seven percent of the total
visibility impairment at Bosque del Apache.\55\ Specifically, the 2021
Texas Regional Haze Plan identifies that the influence due to
particulate sulfate from Texas sources is more than five times the
influence of New Mexico sources, and the influence due to particulate
nitrate from Texas sources is nearly twice the influence of New Mexico
sources.\56\ Thus, Texas's PSAT modeling suggests that emissions from
Texas sources are reasonably anticipated to contribute to visibility
impairment at the Bosque del Apache Class I area given the low
threshold for visibility impact on Class I areas discussed
previously.\57\ Therefore, Texas did not complete its obligation under
40 CFR 51.308(f), which provides that each state's plan ``must address
regional haze in each mandatory Class I Federal area located within the
State and in each mandatory Class I Federal area located outside the
State that may be affected by emissions from within the State,'' and
(f)(2), which requires each state's plan to include a long-term
strategy that addresses regional haze in such Class I areas.
---------------------------------------------------------------------------

\52\ Texas also did not conduct an AOI analysis for the
Bandelier Class I area for the same reasons provided for Bosque del
Apache.
\53\ 2021 Texas Regional Haze Plan, appendix A at 19 of 227;
2021 Texas Regional Haze Plan, Response to Comments at 460 of 653.
\54\ Comprehensive Air quality Model with extensions (CAMx)
Particulate Source Apportionment Technique (PSAT). CAMx PSAT is
capable of tracking source category emissions and separate source
regions for certain PM species and precursor emissions. We discuss
this further in the Technical Support Document (TSD) for this
action, included in the docket.
\55\ 2021 Texas Regional Haze Plan, appendix A at 26 of 227.
\56\ See 2021 Texas Regional Haze Plan, table 8-41 at 8-53; and
2021 Texas Regional Haze Plan, appendix F at F-59 to F-61.
\57\ 2021 Texas Regional Haze Plan, appendix F at F-36.
---------------------------------------------------------------------------

D. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress

Section 51.308(f)(1) requires states to determine the following for
``each mandatory Class I Federal area located within the State'':
baseline visibility conditions for the most impaired and clearest days,
natural visibility conditions for the most impaired and clearest days,
progress to date for the most impaired and clearest days, the
differences between current visibility conditions and natural
visibility conditions, and the URP. This section also provides the
option for states to propose adjustments to the URP line for a Class I
area to account for visibility impacts from anthropogenic sources
outside the United States and/or the impacts from wildland prescribed
fires that were conducted for certain, specified objectives.\58\
---------------------------------------------------------------------------

\58\ 40 CFR 51.308(f)(1)(vi)(B).
---------------------------------------------------------------------------

In Chapter 4 of the 2021 Texas Regional Haze Plan, Texas determines
and presents the baseline, natural, and current visibility conditions
for both the 20 percent most anthropogenically impaired days and the 20
percent clearest days for the State's two Class I Areas consistent with
the EPA's RHR and guidance. In the 2021 Texas Regional Haze Plan, the
TCEQ used visibility data from IMPROVE monitoring sites to calculate
baseline visibility conditions. Consistent with the RHR, Texas
calculated baseline visibility based on data from 2000-2004. For Big
Bend specifically, baseline visibility conditions are based on valid
data for 2001 through 2004 because 2000 did not meet completeness
criteria.\59\ Baseline visibility indices for Big Bend and Guadalupe
Mountains are presented in the 2021 Texas Regional Haze Plan in table
4-4. In our review, we identified that the information provided by
Texas in Chapter 4 of its 2021 Regional Haze Plan as to the baseline
and current conditions on the 20 percent clearest days is inconsistent
with the IMPROVE monitoring data and information presented in Chapter
8. Based on the information in table 8-42 of the 2021 Regional Haze
Plan, Texas identifies the correct data set for where this information
is located but presents the incorrect data in Chapter 4. Based on the
data source that Texas identified in Chapter 8, we present information
in tables 2 and 4 consistent with information in Chapter 8 of its Plan
and the IMPROVE monitoring data.\60\
---------------------------------------------------------------------------

\59\ See 2021 Texas Regional Haze Plan at 4-4.
\60\ <a href="https://views.cira.colostate.edu/fed/">https://views.cira.colostate.edu/fed/</a>. See also 2020 Data
Completeness Memo, table 1.

[[Page 83350]]

Table 2--Estimate of Baseline Visibility Conditions (2000-2004) for Class I Areas in Texas
----------------------------------------------------------------------------------------------------------------
Most impaired haze index Clearest haze index
Class I area (dv) (dv)
----------------------------------------------------------------------------------------------------------------
Big Bend.................................................... 15.57 5.78
Guadalupe Mountains......................................... 14.60 5.92
----------------------------------------------------------------------------------------------------------------

Using the revised IMPROVE algorithm \61\ and the methodology
described in the 2018 Visibility Tracking Guidance, the TCEQ determined
natural visibility conditions for Big Bend and Guadalupe Mountains,
presented in table 4-3 of the 2021 Texas Regional Haze Plan, and
included in the following table 3.
---------------------------------------------------------------------------

\61\ Marc Pitchford et al., Revised Algorithm for Estimating
Light Extinction from IMPROVE Particle Speciation Data, j. Air &
waste mgmt. Ass'n 1326, 1326-1336 (2007), <a href="https://doi.org/10.3155/1047-3289.57.11.1326">https://doi.org/10.3155/1047-3289.57.11.1326</a>.

Table 3--Estimate of Natural Visibility Conditions for Class I Areas in Texas
----------------------------------------------------------------------------------------------------------------
Most impaired haze index Clearest haze index
Class I area (dv) (dv)
----------------------------------------------------------------------------------------------------------------
Big Bend.................................................... 5.33 1.62
Guadalupe Mountains......................................... 4.83 0.99
----------------------------------------------------------------------------------------------------------------

The current visibility conditions, which are based on 2014-2018
monitoring data, are presented in the 2021 Texas Regional Haze Plan in
table 4-5 with corrected values included in the following table 4.

Table 4--Estimate of Current Visibility Conditions (2014-2018) for Class I Areas in Texas
----------------------------------------------------------------------------------------------------------------
Most impaired haze index Clearest haze index
Class I area (dv) (dv)
----------------------------------------------------------------------------------------------------------------
Big Bend.................................................... 14.06 5.17
Guadalupe Mountains......................................... 12.64 4.73
----------------------------------------------------------------------------------------------------------------

While the 2021 Texas Regional Haze Plan does not specifically
present the differences between current visibility conditions and
natural visibility conditions as well as the progress to date, we
include these calculations using the corrected information in tables 5
and 6.

Table 5--Progress to Date
(Differences Between Baseline and Current Conditions)
----------------------------------------------------------------------------------------------------------------
Class I area Most impaired (dv) Clearest haze (dv)
----------------------------------------------------------------------------------------------------------------
Big Bend.................................................... 1.51 0.61
Guadalupe Mountains......................................... 1.96 1.19
----------------------------------------------------------------------------------------------------------------

Table 6--Differences Between Current and Natural Conditions
----------------------------------------------------------------------------------------------------------------
Class I area Most impaired (dv) Clearest haze (dv)
----------------------------------------------------------------------------------------------------------------
Big Bend.................................................... 8.73 3.55
Guadalupe Mountains......................................... 7.81 3.74
----------------------------------------------------------------------------------------------------------------

The Regional Haze Rule allows states the option to adjust the 2064
glidepath endpoint to account for both international anthropogenic and
certain prescribed fire impacts at Class I areas. In the EPA's
September 2019 Availability of Modeling Data and Associated Technical
Support Document for the EPA's Updated 2028 Visibility Air Quality
Modeling memorandum \62\ (EPA 2019 Modeling TSD), the EPA used 2028
modeling results to quantify the international and prescribed fire
impacts at Class I areas on the 20% most anthropogenically impaired
days. Texas used its own CAMx modeling results to adjust the URP to
account for international anthropogenic emissions consistent with the
approach used by the EPA in the TSD associated with the EPA's Updated
2028 Visibility Air Quality Modeling memorandum. Texas's adjusted URP
for Big Bend and Guadalupe Mountains are presented in Figures 8-28 and
8-29 of its 2021 Texas

[[Page 83351]]

Regional Haze Plan.\63\ Texas's adjusted URP in 2028 on the 20% most
impaired visibility days is 14.38 deciviews for Big Bend and 12.81 for
Guadalupe Mountains.\64\ These values for Big Bend and Guadalupe
Mountains are within the range of 2028 adjusted glidepath values
provided for in the EPA 2019 Modeling TSD.\65\
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\62\ Availability of Modeling Data and Associated Technical
Support Document for the EPA's Updated 2028 Visibility Air Quality
Modeling. <a href="https://www.epa.gov/visibility/technical-support-document-epas-updated-2028-regional-haze-modeling">https://www.epa.gov/visibility/technical-support-document-epas-updated-2028-regional-haze-modeling</a>. The EPA Office of Air
Quality Planning and Standards, Research Triangle Park (Sep. 19,
2019).
\63\ After Texas adjusted the glidepath endpoint to account for
contributions from international anthropogenic emissions, one site
(Salt Creek, NM) was projected to be above the adjusted URP. The EPA
2019 Modeling TSD also had Salt Creek above the adjusted glidepath.
\64\ 2021 Texas Regional Haze Plan, table 8-43 at 8-59 and table
8-46 at 8-67.
\65\ EPA 2019 Modeling TSD at 54, 56, and table 5-2 at 59.
---------------------------------------------------------------------------

The EPA finds that the visibility condition calculations for the
two Texas Class I Areas meet the requirements of 40 CFR 51.308(f)(1).
Therefore, the EPA proposes to approve the portions of the 2021 Texas
Regional Haze Plan relating to 40 CFR 51.308(f)(1).

E. Long-Term Strategy for Regional Haze

Each State having a Class I area within its borders or emissions
that may affect visibility in a Class I area must develop a long-term
strategy for making reasonable progress towards the national visibility
goal.\66\ As explained in the Background section of this notice,
reasonable progress is achieved when all states contributing to
visibility impairment in a Class I area are implementing the measures
determined--through application of the four statutory factors to
sources of visibility impairing pollutants--to be necessary to make
reasonable progress.\67\ Each state's long-term strategy must include
the enforceable emission limitations, compliance schedules, and other
measures that are necessary to make reasonable progress.\68\ All new
(i.e., additional) measures that are the outcome of four-factor
analyses are necessary to make reasonable progress and must be in the
long-term strategy. If the outcome of a four-factor analysis and other
measures necessary to make reasonable progress is that no new measures
are reasonable for a source, that source's existing measures are
necessary to make reasonable progress, unless the State can demonstrate
that the source will continue to implement those measures and will not
increase its emission rate. Existing measures that are necessary to
make reasonable progress must also be in the long-term strategy. In
developing its long-term strategies, a State must also consider the
five additional factors in Sec. 51.308(f)(2)(iv). As part of its
reasonable progress determinations, the State must describe the
criteria used to determine which sources or group of sources were
evaluated (i.e., subjected to four-factor analysis) for the second
implementation period and how the four factors were taken into
consideration in selecting the emission reduction measures for
inclusion in the long-term strategy.\69\
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\66\ CAA 169A(b)(2)(B).
\67\ 40 CFR 51.308(f)(2)(i).
\68\ 40 CFR 51.308(f)(2).
\69\ 40 CFR 51.308(f)(2)(i), (iii).
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1. Source Selection
a. Overview of Texas's Source Selection
Under 40 CFR 51.308(f)(2)(i), states must evaluate and determine
the emission reduction measures that are necessary to make reasonable
progress by considering the costs of compliance, the time necessary for
compliance, the energy and non-air quality environmental impacts of
compliance, and the remaining useful life of any potentially affected
anthropogenic source of visibility impairment.\70\ In doing so, states
should consider evaluating major and minor stationary sources or groups
of sources, mobile sources, and area sources as part of their long-term
strategy for regional haze. Furthermore, the State must include in its
implementation plan a description of the criteria it used to determine
which sources or groups of sources it evaluated. States may rely on
technical information developed by the RPOs of which they are members
to select sources for four-factor analysis and to conduct that
analysis, as well as to satisfy the documentation requirements under 40
CFR 51.308(f)(2). Texas, however, conducted its own analysis separate
from CenSARA's analysis to select sources for further evaluation using
the four statutory factors.
---------------------------------------------------------------------------

\70\ See also CAA 169A(g)(1).
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Texas focused on sources of NO<INF>X</INF> and SO<INF>2</INF>
emissions in its control strategy analysis for the second planning
period. Texas explained these are the main anthropogenic pollutants
that affect visibility at Class I areas in Texas and Class I areas in
neighboring states. Texas further stated that, ``on an individual
basis, point sources are the largest contributors to SO<INF>2</INF> and
NO<INF>X</INF>,'' and thus Texas elected to focus on point sources in
this planning period.\71\
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\71\ 2021 Texas Regional Haze Plan at 7-3.
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Texas's source selection methodology relied on a two-step approach.
As the first step for source selection, Texas developed areas of
influence (AOIs) for thirteen \72\ Class I areas (in Texas and nearby
states) to identify areas that may contain sources of NO<INF>X</INF>
and SO<INF>2</INF> that were expected to contribute to visibility
impairment at these areas. The AOIs are graphical representations of
the extinction weighted residence time (EWRT), which combines air flow
patterns with ammonium sulfate and ammonium nitrate extinction measured
at IMPROVE monitors at the Class I areas on the 20% most impaired days.
The TCEQ used the AOI of a Class I area as a brightline cutoff to
define the boundaries within which to further evaluate sources located
within that area. As the second step, Texas then applied a Q/d
threshold for NO<INF>X</INF> and for SO<INF>2</INF> of greater than or
equal to five to point sources located within the geographical area of
the selected AOI threshold.\73\ As a result, any source within the AOI
boundaries with a Q/d less than five or any source, regardless of its
Q/d, that fell outside of the AOI boundaries were eliminated from
further consideration.
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\72\ As discussed previously in section IV.C., the monitor for
Guadalupe Mountains also serves as the monitor for Carlsbad Caverns
in New Mexico.
\73\ To calculate the Q/d for point sources, the TCEQ used 2028
projected emissions (Q in tons per year) and distance from the Class
I area monitor to the source (d in kilometers). For non-EGUs, Texas
estimated 2028 future year emissions from 2016 reported emissions
from the State of Texas Air Reporting System (STARS) coupled with
growth factors developed by the consulting firm, Eastern Research
Group, Inc. (ERG) See 2021 Texas Regional Haze Plan at 7-9. For
EGUs, the TCEQ used data from the Eastern Regional Technical
Advisory Committee (ERTAC) to estimate EGU projections for 2028. See
2021 Texas Regional Haze Plan at 7-9.
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Although Texas determined AOIs for 13 Class I areas in Texas and
nearby states, Texas's 2021 Regional Haze Plan focused only on those
Class I areas where sources with a Q/d greater than or equal to five
fell within the AOI boundary.\74\ Following this methodology, Texas
selected 18 sources for further analysis for only four Class I areas:
Wichita Mountains, Caney Creek, Guadalupe Mountains, and Salt
Creek.\75\
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\74\ See 2021 Texas Regional Haze Plan, Figure 7-1 at 7-4 and
Figure 7-2 at 7-5. Texas stated that those additional AOIs not
represented in those figures in the SIP did not add additional
sources for consideration. 2021 Texas Regional Haze Plan at 7-6.
\75\ See Texas 2021 Regional Haze Plan at 7-5 to 7-6. Presented
Class I areas are: Caney Creek, Guadalupe Mountains, Salt Creek, and
Wichita Mountains for the NO<INF>X</INF> analysis, and Caney Creek,
Guadalupe Mountains, and Wichita Mountains for the SO<INF>2</INF>
analysis.

[[Page 83352]]

Table 7--Texas's Source Selection for Its 2021 Regional Haze Plan \76\
----------------------------------------------------------------------------------------------------------------
Company/site name Unit(s) Class I area(s) Pollutant(s)
----------------------------------------------------------------------------------------------------------------
Coleto Creek Power/Coleto Creek (1) coal boiler........... Wichita Mountains.... SO2.
Power Station.
Southwestern Electric Power/Welsh (2) coal boilers.......... Caney Creek & Wichita SO2.
Power Plant. Mountains.
AEP/Pirkey Power Plant............ (1) coal boiler........... Caney Creek & Wichita SO2.
Mountains.
NRG Energy/Limestone Electric (2) coal boilers.......... Wichita Mountains.... SO2.
Generating Station.
Vistra Energy/Martin Lake Electric (3) coal boilers.......... Caney Creek & Wichita SO2.
Station. Mountains.
San Miguel Electric Cooperative/ (1) coal boiler........... Guadalupe Mountains & SO2.
San Miguel Elec. Plant. Wichita Mountains.
Public Service Co. of Oklahoma/ (1) coal boiler........... Wichita Mountains.... SO2 & NOX.
Oklaunion Power Station.
Vistra Energy/Oak Grove Steam (2) coal boilers.......... Wichita Mountains.... SO2.
Electric Station.
Holcim Texas LP/Midlothian Plant.. (2) cement kilns.......... Wichita Mountains.... SO2.
Vitro Flat Glass/Works No. 4 (2) glass melting furnaces Wichita Mountains.... SO2 & NOX.
Wichita Falls Plant.
Graphic Packaging International/ (4) boilers: (2) black Caney Creek.......... NOX.
Texarkana Mill. liquor solids & NG; (1)
NG & fuel oil; (1) NG,
fuel oil, & other
materials.
El Paso Natural Gas Co./Keystone (15) reciprocating engines Guadalupe Mountains & NOX.
Compressor Station. Salt Creek.
El Paso Natural Gas Co./Cornudas (6) turbines.............. Guadalupe Mountains.. NOX.
Plant.
El Paso Natural Gas Co./Guadalupe (1) turbine............... Guadalupe Mountains.. NOX.
Compressor Station.
GCC Permian/Odessa Cement Plant... (2) cement kilns.......... Guadalupe Mountains.. NOX.
Orion Engineered Carbons/Orange (1) incinerator; (4) Caney Creek.......... SO2.
Carbon Black Plant. dryers; (2) tail gas and
NG boilers; (1) flare.
Oxbow Calcining/Oxbow Calcining- (4) coke calcining kilns.. Caney Creek.......... SO2.
Port Arthur.
Trinity Lightweight Aggregate (1) lightweight aggregate Wichita Mountains.... SO2.
(TRNLWS)/Streetman Plant. kiln.
----------------------------------------------------------------------------------------------------------------

b. EPA's Evaluation of Texas's Source Selection Methodology
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\76\ Texas 2021 Regional Haze Plan, table 7-5.
---------------------------------------------------------------------------

In identifying the required emission limits, schedules of
compliance, and other measures as may be necessary to make reasonable
progress toward meeting the national goal, States first select sources
for consideration of the four statutory factors.\77\ Under the RHR,
States have flexibility in conducting their source selection; however,
Texas's source selection methodology was neither well-reasoned nor
adequately justified.\78\ Notably, Texas did not select any sources for
further analysis of control measures that may be necessary for
inclusion as part of the long-term strategy to make reasonable progress
for Big Bend National Park and did not select any SO<INF>2</INF>
sources for consideration for Salt Creek. Moreover, the EPA finds the
source selection methodology used by Texas was not adequately or
accurately described. As such, the threshold Texas applied to define
its AOIs was not justified. Without the proper justification, it is
unclear how, despite these deficiencies, Texas makes reasonable
progress at these Class I areas.
---------------------------------------------------------------------------

\77\ See 40 CFR 51.308(f)(2); CAA 169A(g)(1).
\78\ 2019 Guidance at 9, 13. The 2019 Guidance explains that in
selecting sources, states must reasonably choose factors and apply
them in a reasonable way given the statutory requirement to make
reasonable progress towards national goal of preventing future and
remedying existing anthropogenic visibility impairment). See CAA
169A(b)(2). To that end, the 2019 Guidance recommends that states
provide a detailed description of how the state used technical
information to select a reasonable set of sources for an analysis of
control measures including the basis for the visibility impact
thresholds the state used (if applicable), and any other relevant
information. See also 2021 Clarifications Memo at 3 (``States cannot
reasonably determine that they are making reasonable progress if
they have not adequately considered the contributors to visibility
impairment. Thus, while states have discretion to reasonably select
sources, this analysis should be designed and conducted to ensure
that source selection results in a set of pollutants and sources the
evaluation of which has the potential to meaningfully reduce their
contributions to visibility impairment.'').
---------------------------------------------------------------------------

i. The TCEQ Failed To Adequately Describe the Criteria It Used To
Select Sources
Under 40 CFR 51.308(f)(2)(i), States are required to include a
``description of the criteria it used to determine which sources or
groups of sources it evaluated.'' Based on our review of the 2021 Texas
Regional Haze Plan, the methodology Texas described in its SIP to
develop its AOIs is inconsistent with, and would not result in, the
AOIs presented in Texas's SIP. Texas states in its SIP that the AOIs
were determined by dividing the EWRT for each cell by the sum total of
all the EWRTs (i.e., EWRT for each cell) across the entire domain.\79\
However, based on the documentation the EPA obtained during early
engagement in the Fall of 2020 and comparing it to what was in its 2021
Regional Haze Plan, Texas actually divided the EWRT for each cell by
the maximum EWRT in the domain for each respective pollutant. There was
thus an inconsistency between what Texas said its methodology was, and
what was in its 2021 Regional Haze Plan submission. Specifically, in
the 2020 early engagement document, Texas stated, ``. . . prior to
plotting the AOIs, the weighted probabilities were scaled to 1 by
dividing the weighted probabilities in each cell by the maximum value
in
---------------------------------------------------------------------------

\79\ 2021 Texas Regional Haze Plan at 7-7.

---------------------------------------------------------------------------

[[Page 83353]]

a cell in the domain.'' \80\ The EPA compared the plotted AOIs Texas
had submitted during the 2020 early engagement period with the plotted
AOIs Texas submitted with its 2021 Regional Haze Plan. These AOIs are
the same, confirming that, despite what Texas stated in its 2021
Regional Haze Plan, Texas was actually following its articulated
methodology in the 2020 early engagement document.
---------------------------------------------------------------------------

\80\ See
``README.AOIdevelopmentFor2021RHSIP_Response_to_EPArequest.20Nov2020u
pdate.docx'' available in the docket for this action.
---------------------------------------------------------------------------

This early engagement information was not included in the proposed
SIP Texas published during its state-level notice-and-comment process.
Thus, Texas's SIP failed to accurately or adequately describe the
criteria actually used in its 2021 Regional Haze Plan submission to
determine which sources, or groups of sources, it chose to evaluate for
additional control measures as required by 40 CFR 51.308(f)(2)(i).
Without an accurate and adequate description of Texas's source
selection methodology, it is not clear from its 2021 Texas Regional
Haze Plan how Texas evaluated and determined the emission reduction
measures that are necessary to make reasonable progress for its second
planning period long-term strategy. We discuss the AOI methodologies
and these inconsistencies further in the Technical Support Document
(TSD) included in the docket for this action.
ii. Texas Failed To Adequately Justify Its AOI Threshold
As noted in the previous section and more fully explained in the
EPA's TSD, Texas selected sources using AOIs it developed for each
Class I area then followed with a Q/d analysis. The AOIs established a
brightline geographic boundary within which Texas selected sources with
a Q/d of greater than or equal to five. In other words, Texas did not
consider a source, regardless of the size of its emissions, if it was
not first within the geographic area defined by the chosen AOI
threshold.
To define the brightline geographic boundaries of the AOIs, Texas
applied a threshold of 0.1 or 10% of the maximum EWRT value for that
AOI.\81\ Texas did not provide any discussion or justification for its
selection of this threshold, nor did Texas explain how this threshold
resulted in evaluating a meaningful set of sources for possible
controls measures to improve visibility impairment. Further, Texas did
not evaluate whether the selected threshold provided for AOIs that
included a sufficiently large area to capture the sources with the
highest emissions, or Q/d values, that impact visibility at certain
Class I areas. The need for a justification is crucial when a State is
applying the threshold as a brightline when selecting sources to
evaluate for additional control measures, such as what Texas did here.
The AOIs generated from EWRTs represent the general location that air
parcels are coming from when visibility extinction is high. However,
unless an appropriate threshold value is applied, they do not
necessarily capture the specific sources of emissions that are
contributing to visibility impairment at the Class I area.\82\ Texas's
approach did not consider the size or location of point sources,
despite articulating a specific focus on point sources,\83\ or the
total emissions captured to support that their approach and chosen
threshold resulted in a reasonable identification of sources for
analysis in development of the long term strategy. This problem is
evident in Texas's 2021 Regional Haze Plan, where several AOIs
contained no sources identified for further consideration and several
large emission sources with Q/d values far exceeding Texas's Q/d
threshold of five being excluded from further consideration because
they were located outside of Texas's generated AOIs.
---------------------------------------------------------------------------

\81\ Texas discusses its AOI and Q/d analysis in section 7.2.1
of its 2021 Texas Regional Haze Plan.
\82\ The 2019 Guidance describes a source selection approach
utilizing residence time analysis that selects sources for further
analysis by giving each point source a score that takes into account
the source's emissions, the daily values of light extinction at a
Class I area, the distance between the source and a Class I area,
and the relative frequency with which wind trajectories indicate
that each source is upwind of the IMPROVE monitoring site. 2019
Guidance at 13. This is the general approach followed by CenSARA and
WRAP.
\83\ Texas found that on an individual basis point sources are
the largest contributors to visibility impairment in Class I areas.
2021 Texas Regional Haze Plan at 7-3.
---------------------------------------------------------------------------

For example, W A Parish is located just outside of Texas's ammonium
sulfate AOIs for both Caney Creek and Wichita Mountains, and outside of
Texas's ammonium sulfate AOI for Big Bend.\84\ The SO<INF>2</INF> Q/d
values for W A Parish are 32.2 for Caney Creek, 28.2 for Wichita
Mountains, and 25.1 for Big Bend.\85\ Tolk Generating Station is also
located outside of Texas's ammonium sulfate AOI for Salt Creek;
however, it has a Q/d value of over 84.\86\ Ammonium sulfate is the
largest contributor to observed light extinction at Salt Creek \87\ but
Texas did not identify any source of SO<INF>2</INF> emissions for
further analysis due to the application of their AOI brightline test
and selected EWRT threshold, despite the large SO<INF>2</INF> emissions
from Tolk and the relative proximity of the facility to Salt Creek.\88\
Given the large emissions from these facilities, these sources likely
are meaningfully contributing to visibility impairment, even if they
happen to fall outside of the chosen Texas AOIs. Based on its analysis
of other coal-fired EGUs with no controls or underperforming controls,
had Texas selected these sources for further evaluation under the four
factors, Texas may have found cost-effective controls available,
resulting in emission reductions that may have been necessary for
inclusion in its long-term strategy to make reasonable progress toward
meeting the national goal. Moreover, Texas did not explain how not
evaluating these high-emitting sources nonetheless results in a long-
term strategy that makes reasonable progress toward the national goal.
---------------------------------------------------------------------------

\84\ See 2021 Texas Regional Haze Plan, Figure 7-2 at 7-5; AOI
for Big Bend located in Texas's EWRT AMDA spreadsheet on TCEQ's AMDA
website at <a href="https://www.tceq.texas.gov/assets/public/implementation/air/sip/haze/EWRT_AMDA_Pivot_final.xlsx">https://www.tceq.texas.gov/assets/public/implementation/air/sip/haze/EWRT_AMDA_Pivot_final.xlsx</a>. This spreadsheet is also
available in our docket as ``Texas EWRT AMDA spreadsheet.xlsx''.
\85\ See ``EPA Q_d Spreadsheet.xlsx'' available in the docket
for this action. The information included in the EPA's spreadsheet
used information available in our docket as ``Texas EWRT AMDA
spreadsheet.xlsx''. See also Letter from Arkansas Department of
Energy and Environment to TCEQ requesting that TCEQ consider, among
other sources, whether performing a four-factor analysis is
appropriate for the W A Parish facility in accordance with 40 CFR
51.308(f)(2)(i) due to impacts on Caney Creek based on CenSARA's AOI
study (Feb. 4, 2020). The letter is available in Appendix A of
Texas's 2021 Regional Haze Plan at 84 of 227. See also Letter from
Oklahoma Department of Environmental Quality to TCEQ requesting that
TCEQ consider further evaluating the W A Parish facility based on
its identification that the source is reasonably anticipated to
contribute to visibility impairment at the Wichita Mountains
Wilderness Area (July 17, 2020). The letter is available in Appendix
A of Texas's 2021 Regional Haze Plan at 125 of 227.
\86\ See AOI for Salt Creek located in ``Texas EWRT AMDA
spreadsheet.xlsx'' available in the docket for this action. See
``EPA Q_d Spreadsheet.xlsx'' available in the docket for this
action. See also Letter from New Mexico Environment Department to
TCEQ requesting among other things that Texas specifically evaluate
the Tolk facility for additional controls based on its impact to
Class I areas in New Mexico, including Salt Creek (Feb. 2, 2021).
The letter is available in Appendix A of Texas's 2021 Regional Haze
Plan at 111 of 227. See also, information provided by the FLMs
during consultation that Tolk and W A Parish merit further
evaluation based on emissions and potential emission reductions
available. The information provided by the FLMs is available in
Appendix A of Texas's 2021 Regional Haze Plan at 205 of 227.
\87\ See 2021 Texas Regional Haze Plan, appendix F, Figure 1-60.
\88\ EPA used information from Texas's EWRT AMDA spreadsheet,
also available in our docket as ``Texas EWRT AMDA
spreadsheet.xlsx''. We used the same information to calculate the
SO<INF>2</INF> Q/d values for Tolk at White Mountain (56) and at
Wheeler Peak (42.7).
---------------------------------------------------------------------------

We therefore find Texas's unjustified use of its selected threshold
and resulting AOIs as a brightline cutoff in

[[Page 83354]]

source selection to be unreasonable. Texas's methodology resulted in
several of the highest emitting SO<INF>2</INF> stationary point sources
in the State of Texas not being selected for further evaluation of
controls to improve visibility impairment at the Class I areas they
likely impact, and in the case of some Class I areas, no sources
selected at all for further analysis using the four statutory factors
for those areas.
iii. PSAT Modeling Results Further Demonstrate Unreasonableness of
Texas's Source Selection Methodology
The 2019 Guidance identifies photochemical modeling and the use of
source apportionment modeling as possible methods to assess PM species
impacts from sources or groups of sources for source selection.\89\
Texas conducted photochemical source apportionment modeling (known as
the Particulate Matter Source Apportionment Technology, or PSAT,
function of CAMx modeling) as part of its 2021 Regional Haze Plan to
evaluate the impact of emissions from source categories on visibility
in Class I areas.\90\ While Texas did not conduct PSAT modeling for the
explicit purpose of source selection, Texas nevertheless included the
results of the PSAT modeling in its SIP.\91\ The EPA finds Texas's own
PSAT modeling results illustrate the flaws in Texas's source selection
methodology.
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\89\ 2019 Guidance at 14-15.
\90\ 2021 Texas Regional Haze Plan at 8-2.
\91\ As explained in our 2019 Guidance, photochemical models are
a more detailed and sophisticated technique for evaluating
visibility impacts. Photochemical modeling considers the dispersion
transformation and deposition processes. Source apportionment can
``tag'' and track emissions sources by any combination of region and
sector, or by individual source. As evidenced in Appendix A of
Texas's 2021 Regional Haze Plan, Texas had the results of the PSAT
modeling at least by March 31, 2020, when Texas presented the
results to the FLMs during a consultation meeting.
---------------------------------------------------------------------------

The TCEQ failed to address in its 2021 Regional Haze Plan how its
source selection approach and resulting failure to select sources for
further analysis to address visibility impairment at Big Bend are
consistent with the CAA's statutory goal and Regional Haze Rule
requirements.\92\ TCEQ's source selection methodology did not identify
any sources for further analysis of control measures that may be
necessary to include in its long-term strategy to make reasonable
progress at Big Bend. The TCEQ's PSAT model results indicate that
emissions from Texas anthropogenic sources account for over 10% of the
total light extinction at Big Bend, and 67% of the light extinction due
to U.S. anthropogenic emissions. \93\ The influence from Texas sources
on light extinction at Big Bend is approximately double the influence
from anthropogenic sources in the rest of the U.S. combined.\94\ While
Texas states that visibility at Big Bend is heavily influenced by
international emissions, the TCEQ has already accounted for this by
adjusting the glidepath for its Class I areas to remove visibility
impairment from international emissions, consistent with the EPA's
guidance, and thus should not be used as a rationale for not evaluating
sources for additional control measures. CAA 169A(a)(1), (b)(2) and the
RHR require states to make reasonable progress towards addressing
anthropogenic impairment from U.S. sources in the second planning
period in furtherance of Congress's national goal.
---------------------------------------------------------------------------

\92\ CAA 169A(a)(1), (b)(2); 40 CFR 51.308(f)(2).
\93\ See 2021 Texas Regional Haze Plan Figure 8-21 at 8-46.
\94\ See 2021 Texas Regional Haze Plan Figure 8-21 at 8-46.
---------------------------------------------------------------------------

The influence of Texas sources on sulfate and nitrate
concentrations at Big Bend shows that emissions from Texas sources are
projected to account for approximately 65.4% of the particulate sulfate
concentration and 59.3% of the nitrate concentration due to U.S.
anthropogenic emissions.\95\ The vast majority (93.9%) \96\ of the
Texas influence on particulate sulfate concentrations at Big Bend can
be attributed to Texas anthropogenic emissions from electricity
generating unit (EGU) point and non-EGU point sources.\97\ Therefore,
these data demonstrate that Texas's AOI analysis and threshold
selection for Big Bend did not adequately identify the relevant sources
that impact visibility impairment for further analysis necessary to
develop a long-term strategy to make reasonable progress at Big Bend.
---------------------------------------------------------------------------

\95\ See 2021 Texas Regional Haze Plan, appendix F, Figure 1-52
at F-54 and Figure 1-53 at F-55.
\96\ See 2021 Texas Regional Haze Plan, appendix F, Figure 1-52
at F-54.
\97\ See 2021 Texas Regional Haze Plan, appendix F, Figure 1-52
at F-54.
---------------------------------------------------------------------------

Similarly, Texas's PSAT modeling also underscores inadequacies with
its source selection for Class I areas in New Mexico, for example, Salt
Creek. As noted above, Texas's AOI analysis for Salt Creek identified
no sources of SO<INF>2</INF> in Texas for consideration for further
analysis. However, the results of Texas's PSAT modeling show that Texas
sources account for almost 12% of the light extinction at Salt
Creek.\98\ The largest contributor to light extinction at Salt Creek is
sulfate.\99\ Focusing on modeled U.S. anthropogenic impacts alone,
Texas anthropogenic sources account for approximately 51.3% of the
particulate sulfate concentrations at Salt Creek.\100\ Texas's chosen
approach for source selection failed to identify any SO<INF>2</INF>
point sources, despite accounting for over half of all the U.S.
anthropogenic particulate sulfate concentrations at Salt Creek.
---------------------------------------------------------------------------

\98\ See 2021 Texas Regional Haze Plan, appendix F at F-36.
\99\ See 2021 Texas Regional Haze Plan, appendix F at F-62.
\100\ See 2021 Texas Regional Haze Plan, appendix F at F-63.
---------------------------------------------------------------------------

Class I areas like Salt Creek that are not projected to be on or
under the glidepath are subject to additional requirements in the RHR.
Under 40 CFR 51.308(f)(3)(ii)(B), Texas must provide a robust
demonstration that there are no additional emission reduction measures
for anthropogenic sources or groups of sources in the State that may
reasonably be anticipated to contribute to visibility impairment in the
Class I area that would be reasonable to include in its own long-term
strategy.\101\ The influence from Texas's point sources on particulate
sulfate concentrations at Salt Creek is more than double the amount of
New Mexico's total (point source, non-point source, and mobile source)
influence on particulate sulfate concentrations at Salt Creek.\102\
Meaning, SO<INF>2</INF> emissions from Texas sources contribute more to
visibility impairment at Salt Creek than SO<INF>2</INF> emissions from
New Mexico sources. Given the meaningful contribution to visibility
impairment demonstrated by its PSAT modeling, Texas's decision not to
select any SO<INF>2</INF> sources for further analysis and
consideration of the four statutory factors (or to adequately justify
the decision not to select these sources) fails to satisfy the
requirement to provide for a robust demonstration for those Class I
areas projected to be above the glidepath, as required by 40 CFR
51.308(f)(3)(ii)(B).
---------------------------------------------------------------------------

\101\ Texas's own modeling and the EPA's modeling demonstrated
that Salt Creek would be above the adjusted glidepath.
\102\ See 2021 Texas Regional Haze Plan, appendix F, Figure 1-61
at F-63.
---------------------------------------------------------------------------

iv. EPA's Conclusions and Proposed Action on Source Selection
The EPA finds the source selection methodology used by Texas was
not adequately described as required by the RHR.\103\ Nevertheless, the
EPA was able to discern the state's approach to

[[Page 83355]]

developing its AOIs which relied upon drawing a boundary based on a
threshold of ten percent of the maximum EWRT values. Texas, however,
did not provide any rationale or justification for this ten percent
threshold. The boundaries of the AOIs were used as a brightline cutoff,
with sources outside the AOIs not given any further consideration. As
demonstrated in previous sections, Texas's methodology was unreasonable
because it resulted in the selection of no sources for further
evaluation at Big Bend and no SO<INF>2</INF> sources for further
analysis at Salt Creek. Texas's own PSAT modeling results confirm that
its methodology was unreasonable because the results show significant
contribution from Texas anthropogenic sources to visibility impairment
at Big Bend and Salt Creek. Texas made no attempt to explain the
disconnect between its PSAT results and its source selection approach.
---------------------------------------------------------------------------

\103\ 40 CFR 51.308(f)(2)(i) (``The State must evaluate and
determine the emission reduction measures that are necessary to make
reasonable progress . . . The State must include in its
implementation plan a description of the criteria it used to
determine which sources or groups of sources it evaluated'').
---------------------------------------------------------------------------

The selection of a reasonable set of sources is a necessary first
step in identifying the required emission limits, schedules of
compliance, and other measures as may be necessary for inclusion in its
long-term strategy to make reasonable progress toward meeting
Congress's goal of preventing any future, and remedying any existing,
impairment at Class I areas after consideration of the four statutory
factors.\104\ It is evident that developing a long term strategy to
make reasonable progress cannot be met, if no sources of pollutants
shown to be meaningful contributors to impairment are selected for
further evaluation. It is further evident that, at least for Big Bend
for both NO<INF>X</INF> and SO<INF>2</INF> and for Salt Creek for
SO<INF>2</INF>, Texas's method of establishing an AOI is not adequate
to identify sources of visibility impairment in Texas.
---------------------------------------------------------------------------

\104\ See 40 CFR 51.308(f)(2).
---------------------------------------------------------------------------

Therefore, the EPA is proposing to disapprove the portion of
Texas's 2021 Regional Haze Plan addressing the regulatory requirements
of the long-term strategy under 40 CFR 51.308(f)(2).
2. Four Factor Analysis
This section discusses the technical bases and information Texas
relied on in the evaluation of emission reduction measures necessary to
make reasonable progress in each Class I area affected by emissions
from Texas when developing its long-term strategy for the second
planning period. As discussed in the preceding section, Texas selected
18 sources for evaluation of emissions reductions necessary to make
reasonable progress.\105\ If a source triggered analysis for both
NO<INF>X</INF> and SO<INF>2</INF>, control strategies for both
pollutants were analyzed separately and concurrently.\106\ Of the 18
sources selected for evaluation, eight are EGU sources and 10 are non-
EGU sources.
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\105\ 2021 Texas Regional Haze Plan table 7-5 at 7-15.
\106\ 2021 Texas Regional Haze Plan at 7-11.
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Based on the statutory and regulatory requirements, Texas evaluated
emission reduction measures that are necessary to make reasonable
progress by considering the four statutory factors listed in CAA Sec.
169A(g)(1) and 40 CFR 51.308(f)(2)(i) for these selected sources. The
four statutory factors are (1) the cost of compliance; (2) the time
necessary for compliance; (3) the energy and non-air quality
environmental impacts of compliance; and (4) the remaining useful life
of any potentially affected sources. This is commonly referred to as
``the four-factor analysis.'' The four statutory factors must be
considered when evaluating and determining the emissions reductions
measures that are necessary to make reasonable progress.\107\ Although
visibility impact is not one of the factors required for consideration
under the CAA and the RHR, Texas opted to evaluate and consider the
visibility benefits from selected control measures evaluated in the
four-factor analysis by conducting photochemical sensitivity
modeling.\108\ In the subsections that follow, we discuss Texas's
analysis of the four statutory factors.
---------------------------------------------------------------------------

\107\ 40 CFR 51.308(f)(2)(i).
\108\ 2021 Texas Regional Haze Plan at 7-11.
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a. Identification of Potential Controls
In accordance with EPA's 2019 Guidance, ``the first step in
characterizing control measures for a source is the identification of
technically feasible control measures for those pollutants that
contribute to visibility impairment.'' \109\ The EPA's 2019 Guidance
does not define the term ``technically feasible;'' however, EPA's
Regional Haze Regulations and Guidelines for Best Available Retrofit
Technology (BART) Determinations (the BART Guidelines) states:
---------------------------------------------------------------------------

\109\ 2019 Guidance at 22.

Control technologies are technically feasible if either (1) they
have been installed and operated successfully for the type of source
under review under similar conditions, or (2) the technology could
be applied to the source under review. Two key concepts are
important in determining whether a technology could be applied:
``availability'' and ``applicability.'' . . . a technology is
considered ``available'' if the source owner may obtain it through
commercial channels, or it is otherwise available within the common
sense meaning of the term. An available technology is ``applicable''
if it can reasonably be installed and operated on the source type
under consideration. A technology that is available and applicable
is technically feasible.\110\
---------------------------------------------------------------------------

\110\ 40 CFR part 51, appendix Y, Section D, Step 2.

A reasonable four-factor analysis will consider the full range of
potentially reasonable options for reducing emissions.\111\ In order to
provide guidance on what control measures should be included in their
four-factor analysis, the RHR Guidance lists examples of different
types of control measures that states may consider.\112\
---------------------------------------------------------------------------

\111\ 2019 Guidance at 22.
\112\ 2019 Guidance at 29-30.
---------------------------------------------------------------------------

For EGUs without existing controls, Texas considered and evaluated
dry sorbent injection (DSI), spray dryer absorber (SDA), and wet
limestone scrubbing systems (wet FGD) as potential SO<INF>2</INF>
control options, and selective catalytic reduction (SCR) and selective
non-catalytic reduction (SNCR) as potential NOx controls.\113\ For EGUs
with existing SO<INF>2</INF> controls, Texas considered and evaluated
upgrading the control efficiency of the controls to 95%.\114\ For non-
EGUs, Texas considered various NO<INF>X</INF> and SO<INF>2</INF>
control options depending on the type of source and whether it had
existing controls.\115\
---------------------------------------------------------------------------

\113\ 2021 Texas Regional Haze Plan, appendix B at B-1.
\114\ 2021 Texas Regional Haze Plan, appendix B at B-1 and B-5
to B-6.
\115\ 2021 Texas Regional Haze Plan, appendix B at B-1.
---------------------------------------------------------------------------

For selected sources where Texas could not identify any feasible
control options for a particular source-type, that particular source
and pollutant was not further evaluated in the four-factor analysis.
Texas stated that it only considered control technologies that have
been demonstrated as technically feasible for units at each source type
and evaluated those control technologies using available unit-specific
data. Texas deemed a given control technology to be ``demonstrated to
be technically feasible'' if it was identified in the EPA's Reasonably
Available Control Technology/Best Available Control Technology/Lowest
Achievable Emission Rate (RACT/BACT/LAER) Clearinghouse or operated in
industrial applications for units within an industry type not in a
performance ``trial'' phase.\116\ Texas further explained that a
control measure or technique that has been established as technically
demonstrated or feasible

[[Page 83356]]

in one industry type was not considered to extend automatically to
other industry types. Based on Texas's approach, Texas determined that
there were no technically feasible controls for three of the 18 sources
selected for further evaluation using the four factors: the Orion
Carbon Black facility in Orange County, the Oxbow Calcining facility in
Jefferson County, and the Streetman facility in Navarro County. These
three determinations are discussed in more detail in the following
paragraphs.
---------------------------------------------------------------------------

\116\ 2021 Texas Regional Haze Plan, appendix B at B-3.
---------------------------------------------------------------------------

Initially we note that Texas's search for available controls relied
primarily on the RACT/BACT/LAER Clearinghouse. BACT and LAER are terms
associated with EPA's ``New Source Review'' (NSR) permitting program
and is triggered when a company is planning to build a new plant or
modify an existing plant such that air pollution emissions will
increase by a large amount. EPA established the RACT/BACT/LAER
Clearinghouse to provide a central data base of air pollution
technology information (including past RACT, BACT, and LAER decisions
contained in NSR permits) to promote the sharing of information among
permitting agencies and to aid in future case-by-case
determinations.\117\ We note that many of the petroleum coke calcining
plants and carbon black plants were constructed prior to the start of
EPA's NSR permitting program and have generally not been modified in
ways that would trigger the permitting programs.\118\ As a result,
Texas's reliance on that RACT/BACT/LAER Clearinghouse is not a
sufficient search for these types of facilities.
---------------------------------------------------------------------------

\117\ See RACT/BACT/LAER Clearinghouse (RBLC) Basic Information
available at <a href="https://www.epa.gov/catc/ractbactlaer-clearinghouse-rblc-basic-information">https://www.epa.gov/catc/ractbactlaer-clearinghouse-rblc-basic-information</a>.
\118\ See, e.g., Port Arthur Steam Energy/Oxbow Corp., available
at <a href="https://chptap.ornl.gov/profile/186/Port_Arthur_Steam-Project_Profile.pdf">https://chptap.ornl.gov/profile/186/Port_Arthur_Steam-Project_Profile.pdf</a>.
---------------------------------------------------------------------------

In fact, several groups commented during Texas's state-level
comment period that there were technically feasible controls available
for petroleum coke calcining facilities similar to the Oxbow facility.
For example, commenters referenced a report which includes a discussion
of a petroleum coke calcining plant that currently operates a DSI
system to control emissions.\119\ Additionally, the report identifies a
Tesoro facility that operates a semi-dry scrubber combined with a wet
electrostatic precipitator that reduces SO<INF>2</INF> emissions in
excess of 95%.\120\ In response to these comments, Texas stated that:
---------------------------------------------------------------------------

\119\ Bay Area Air Quality Management District Regulation 9,
Rule 14 Report at 4, 9 (Oct. 2015).
\120\ Bay Area Air Quality Management District Regulation 9,
Rule 14 Report at 11 (Oct. 2015).

The control technology the commenter provided may be technically
feasible for petroleum coke calcining manufacturing sites but would
not necessarily be considered technically demonstrated directly on
the kilns such that this technology could be implemented at Oxbow's
Port Arthur facility as suggested by the commenter. The possible
control options suggested by the commenter would require
modification to a site's operational process such that a potential
SO<INF>2</INF> post-combustion control strategy could technically be
implemented to control SO<INF>2</INF> emissions from petroleum coke
calcining kilns. The TCEQ notes these potential strategies would be
implemented downstream of the kiln, or kilns, and not directly on
the kiln. The operational process modification would require
additional process units to the site to make the potential post-
combustion SO<INF>2</INF> control measure technically feasible,
thereby increasing capital expenditures not directly associated with
the new, additional control measure but necessary for the control
measure to effectively function and control SO<INF>2</INF> emissions
from the petroleum coke calcining kiln. The TCEQ contends these
higher-level control analysis approaches require much broader and
resource intensive engineering and economic analyses, and they may
not result in the potential control strategy being deemed cost-
effective or reasonable and necessary for making reasonable progress
for long-term strategies for a planning period.\121\
---------------------------------------------------------------------------

\121\ 2021 Texas Regional Haze Plan, Response to Comments, at
481-482 of 653.

While Texas's response indicates that such control technologies may
not be cost effective based on the modifications that may need to occur
at the site, such a determination would necessarily come out of a four-
factor analysis; it does not explain why Texas's SIP continued to find
that such control measures were not technically feasible.\122\ In fact,
it acknowledges that such control technologies may be technically
feasible. To the extent Texas is relying on the fact that the costs of
this control technology would be prohibitive, Texas needed to provide a
cost analysis to document and support such an assumption.\123\
---------------------------------------------------------------------------

\122\ See EPA's TSD for this action, available in the docket,
for additional information regarding the installation and operation
of controls on petroleum coke calcining plants.
\123\ 40 CFR 51.308(f)(2)(iii).
---------------------------------------------------------------------------

Furthermore, information provided by Oxbow during Texas's comment
period acknowledge that while there is limited publicly available
information there are ``a few commercially operating post-combustion
SO<INF>2</INF> controls systems installed on petroleum coke kilns.''
\124\ Oxbow also provided a four-factor analysis conducted by Sargent &
Lundy.\125\ Specifically, Sargent & Lundy concluded that, based on
engineering judgment and information from control system vendors,
several control technologies were technically feasible and commercially
available including: a DSI system with a fabric filter; \126\ a spray
dryer flue gas scrubber system; \127\ a wet limestone scrubbing system;
\128\ and a circulating dry scrubber system.\129\ Despite information
provided to Texas to the contrary, the State continued to find that
control technologies were not technically feasible. Therefore, Texas's
determination that such control technologies were not technically
feasible for petroleum coke calcining facilities was not reasonable. As
a result, because Texas selected this source for further evaluation of
control measures, it was unreasonable for Texas to not take into
consideration the four statutory factors to determine whether there
were cost-effective measures that were thus necessary for reasonable
progress in fulfillment of their long-term strategy requirements for
the second planning period.\130\
---------------------------------------------------------------------------

\124\ Oxbow Comments on 2021 Texas Regional Haze Plan, at 306 of
653. According to a 2022 technical support document (TSD) prepared
by EPA, there are only approximately 15 petroleum coke calcining
facilities operating in the United States. The EPA 2022 TSD is
available in the docket for this action.
\125\ Oxbow Comments on 2021 Texas Regional Haze Plan, Report
from Sargent & Lundy at 312 of 653.
\126\ Oxbow Comments on 2021 Texas Regional Haze Plan, Report
from Sargent & Lundy at 338 of 653.
\127\ Oxbow Comments on 2021 Texas Regional Haze Plan, Report
from Sargent & Lundy at 336 of 653.
\128\ Oxbow Comments on 2021 Texas Regional Haze Plan, Report
from Sargent & Lundy at 334 of 653.
\129\ Oxbow Comments on 2021 Texas Regional Haze Plan, Report
from Sargent & Lundy at 336 of 653.
\130\ We discuss additional examples of existing controls at
coke calcining facilities in the TSD for this action, included in
the docket.
---------------------------------------------------------------------------

Texas received similar comments regarding Texas's determination
that there were no feasible controls for the Orion carbon black plant.
Notably, the commenter states that the EPA had entered into consent
decrees with several carbon black manufacturing companies that required
control of SO<INF>2</INF> emissions to 95%.\131\ In response to these
comments, Texas stated that while these consent decrees required
certain control efficiencies, installing controls on carbon black
facilities had yet to be demonstrated in practice. However, the EPA
entered into a consent decree with

[[Page 83357]]

the carbon black manufacturing company Cabot, which required the
installation of wet gas scrubbers to control SO<INF>2</INF> emissions
from their carbon black units. While the compliance dates were
delayed,\132\ Cabot completed construction of the wet gas scrubber at
its Canal Plant in 2020.\133\ Thus, the available information
identifies technically feasible and available control technologies for
carbon black facilities. Therefore, Texas's determination that no
control technologies were technically feasible was unreasonable. Texas
should have conducted a four-factor analysis for the Orion carbon black
plant considering these available controls to determine whether cost-
effective control measures were necessary for reasonable progress in
fulfillment of its long-term strategy requirements.
---------------------------------------------------------------------------

\131\ See 2021 Texas Regional Haze SIP, Comments by Sierra Club,
et al., on Texas's Regional Haze SIP at 253 of 653.
\132\ See, United States of America, et al. v. Cabot
Corporation, Civil Action Number 6:13-cv-03095 (W.D. LA), Second
Amendment to Consent Decree (filed Dec. 22, 2017) and available in
the docket for this action.
\133\ See Cabot press release dated June 26, 2020, regarding the
successful installation of control technologies, available at
<a href="https://investor.cabot-corp.com/node/21156">https://investor.cabot-corp.com/node/21156</a>.
---------------------------------------------------------------------------

Texas also received comments during Texas's state-level public
comment period that there were technically feasible controls identified
for lightweight aggregate plants like Streetman's plant.\134\
Specifically, commenters referenced EPA's AP-42 emission factor
documentation \135\ for lightweight aggregate manufacturing. Among
other information, the document identifies that emissions from kilns at
these lightweight aggregate facilities are controlled with wet
scrubbers as well as fabric filters and electrostatic precipitators
(ESPs). In response to this information, Texas stated that review of
the data and information in the EPA's AP-42 emission factor dataset led
the TCEQ to conclude that ``while wet scrubbers designed for PM control
may result in some emissions reductions of SO<INF>2</INF>, the TCEQ
does not view this as a control strategy for the direct control of
SO<INF>2</INF> that could result in meaningful SO<INF>2</INF> emissions
reductions.'' \136\
---------------------------------------------------------------------------

\134\ See 2021 Texas Regional Haze Plan, Comments by Sierra
Club, et al. on Texas's Regional Haze SIP at 252 of 653.
\135\ AP-42 emission factors are published by EPA and serve as
the primarily compilation of emission factor information. The
various chapters contain emissions factors and process information
for more than 200 air pollution source categories. A source category
is a specific industry sector or group of similar emitting sources.
The emissions factors have been developed and compiled from source
test data, material balance studies, and engineering estimates. See
AP-42: Compilation of Air Emissions Factors from Stationary Sources
available at <a href="https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors-stationary-sources">https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors-stationary-sources</a> for more information.
\136\ 2021 Texas Regional Haze Plan, Response to Comments at
482-483 of 653.
---------------------------------------------------------------------------

While the EPA's AP-42 emission factor documentation discusses the
use of scrubbers to control PM emissions, it also provides information
and emission factors related to the control of SO<INF>2</INF> emissions
from the installation of wet scrubbers.\137\ Several of the studies
referenced in the documentation were done to measure SO<INF>2</INF>
emissions.\138\ This information together shows reductions in emissions
of SO<INF>2</INF> from the installation of wet scrubbers at lightweight
aggregate plants.\139\ Regardless of whether the main pollutant of
concern from these types of facilities is PM or SO<INF>2</INF>, Texas
does not adequately or reasonably explain how a proven control
technology, installed within the same industry type and for which
reduces the pollutant of concern (SO<INF>2</INF>), becomes technically
infeasible based on the fact that it also reduces PM. Texas's
determination that there were no technically available controls for
lightweight aggregate plants such as the Streetman facility was
unreasonable and unsupported by information provided to Texas during
its public comment period.\140\ Therefore, it was unreasonable for
Texas not to have evaluated potential control measures for the
Streetman facility using the four statutory factors to determine
whether control measures were necessary for reasonable progress in
fulfillment of their long-term strategy requirements.
---------------------------------------------------------------------------

\137\ AP-42, section 11.20 available at <a href="https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-fifth-edition-volume-i-chapter-11-mineral-products-0">https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-fifth-edition-volume-i-chapter-11-mineral-products-0</a> and in the docket for this action.
\138\ See AP-42, section 11.20 See also AP-42 section 11.20 at
pgs. 5, 10-12.
\139\ See AP-42, section 11.20, table 4-13, Emission factors for
rotary kilns without a scrubber are 5.6 lbs SO<INF>2</INF>/ton feed,
with a scrubber 3.4 lbs SO<INF>2</INF>/ton feed.
\140\ See 2021 Texas Regional Haze Plan, Comments by Sierra
Club, et al, on Texas's Regional Haze SIP at 252 of 653. See also
2021 Texas Regional Haze Plan, appendix A at 206 of 227.
---------------------------------------------------------------------------

b. Cost of Compliance
Texas evaluated the cost of compliance for each control option
determined to be technically feasible for each selected EGU and non-EGU
to arrive at an annualized cost and cost per ton of emissions reduced
($/ton), also referred to as a cost-effectiveness calculation, for each
control option.\141\ Texas stated that as part of the cost analysis,
individual units at a source selected for evaluation with
NO<INF>X</INF> or SO<INF>2</INF> emissions of less than five percent of
the facility's total emissions of the same pollutant were eliminated
from further analysis.\142\ Texas explained that excluding such units
with smaller emissions is reasonable with respect to application of the
cost of compliance criterion because controlling these smaller units
would not be justified at this time considering both the cost to
control and the anticipated improvement in visibility. Using this
approach, Texas focused on the units with relatively greater
NO<INF>X</INF> and SO<INF>2</INF> emissions at a given source.
---------------------------------------------------------------------------

\141\ 2021 Texas Regional Haze Plan, appendix B.
\142\ 2021 Texas Regional Haze Plan, appendix B at B-3.
---------------------------------------------------------------------------

In the cost analysis for EGUs without existing controls, Texas
stated it estimated the capital cost and annual operating and
maintenance costs of technically feasible air pollution control options
using the most recent data available from Sargent & Lundy.\143\ In the
cost analysis for upgrading scrubbers at EGUs, Texas provided an
example cost, but did not explain how that example was used.\144\ In
the cost analysis for non-EGUs, Texas stated it estimated the capital
cost and annual operating and maintenance costs of technically feasible
air pollution control options using cost data and information from the
EPA and available industry literature.\145\ For one non-EGU source, the
Works No. 4 Glass Plant, Texas relied on vendor cost information for
capital cost and annual operating and maintenance costs of control
equipment.\146\ For all sources, Texas estimated annualized capital
costs by multiplying the capital costs by the capital recovery
factor.\147\ The capital recovery factor accounts for source financing
of air pollution control equipment and is based on the assumed
equipment life and interest rate. Texas stated that ``capital recovery
factors were estimated using the techniques listed in the EPA's Control
Cost Manual'' where it found appropriate.\148\ Texas estimated the
capital recovery factor assuming an interest rate of 10 percent and an
equipment life of five, 15, and 30 years. Ultimately, Texas chose to
base its cost analysis on a

[[Page 83358]]

capital life of 15 years for all selected sources.\149\
---------------------------------------------------------------------------

\143\ 2021 Texas Regional Haze Plan at 7-11 to 7-12.
\144\ 2021 Texas Regional Haze Plan, appendix B at B-12.
\145\ 2021 Texas Regional Haze Plan, appendix B at B-12.
\146\ 2021 Texas Regional Haze Plan, appendix B at B-7 to B-8,
B-12.
\147\ 2021 Texas Regional Haze Plan, appendix B at B-14.
\148\ 2021 Texas Regional Haze Plan, appendix B at B-14.
\149\ 2021 Texas Regional Haze Plan, appendix B at B-14.
---------------------------------------------------------------------------

Texas stated that annual operating and maintenance costs associated
with each control option evaluated ``were estimated from the same data
and information used for estimating capital costs for each source.''
\150\ Texas added the annualized capital cost and the annual operating
and maintenance cost to arrive at the total annualized cost for each
control option for each source.\151\ After estimating the potential
emission reductions of each control option using baseline emissions
from the EPA's 2018 Clean Air Markets Program Data (AMPD) emission data
for EGUs and 2016 TCEQ point source emission inventory data for non-
EGUs, the total annualized cost was divided by the tons of pollutant
emissions reduced to estimate the cost per ton of emissions reduced ($/
ton), or cost-effectiveness.\152\ Texas then applied a cost-
effectiveness ($/ton) threshold of $5,000/ton for NO<INF>X</INF> and
SO<INF>2</INF> emissions reduced to eliminate controls from further
consideration by explaining that this allowed for the identification of
sources to which potential control measures could be applied cost-
effectively.\153\ The results of Texas's cost analysis are presented in
the following tables.\154\
---------------------------------------------------------------------------

\150\ 2021 Texas Regional Haze Plan, appendix B at B-14.
\151\ 2021 Texas Regional Haze Plan, appendix B at B-14.
\152\ 2021 Texas Regional Haze Plan, appendix B at B-14.
\153\ 2021 Texas Regional Haze Plan, appendix B at B-15.
\154\ The information contained in tables 8 through table 17 are
presented in the 2021 Texas Regional Haze Plan, appendix B at B-16-
B-42.

Table 8--Texas's Cost Estimates of SO2 Controls for EGUs Without Existing Controls
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2 5-Year life 15-Year life 30-Year life
baseline Control SO2 cost- cost- cost-
Source emissions Control efficiency reduction effectiveness effectiveness effectiveness
(tons/yr) (%) (tons/yr) ($/ton) ($/ton) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Coleto Creek Unit 1................. 13,213 DSI..................... 90 11,892 $3,261 $3,022 $2,976
SDA..................... 95 12,552 6,720 3,884 3,340
Wet FGD................. 98 12,949 7,406 4,215 3,603
Welsh Unit 1........................ 7,528 DSI..................... 90 6,775 4,406 4,029 3,957
SDA..................... 95 7,152 11,380 6,481 5,540
Wet FGD................. 98 7,377 12,032 6,812 5,811
Welsh Unit 3........................ 6,694 DSI..................... 90 6,025 4,814 4,394 4,314
SDA..................... 95 6,359 12,622 7,179 6,135
Wet FGD................. 98 6,560 13,357 7,558 6,445
--------------------------------------------------------------------------------------------------------------------------------------------------------

Table 9--Texas's Cost Estimates of SO2 Wet Scrubber Upgrades for EGUs
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2 reduction Cost-effectiveness ($/ton)
SO2 baseline Annual due to scrubber -----------------------------
Unit size emissions Capital cost operating and upgrade at 95%
Source (MW) (tons/yr) ($) maintenance control 5-Year 15-Year 30-Year
costs ($) efficiency (tons/ life life life
yr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
AEP Pirkey Unit 1.............................. 721 5,085 99,921,030 2,740,188 3,874 $7,511 $4,098 $3,443
Limestone Unit 1............................... 893 4,156 123,757,947 3,393,881 3,212 11,222 6,123 5,145
Limestone Unit 2............................... 957 4,164 132,627,498 3,637,115 3,259 11,853 6,467 5,434
Martin Lake Unit 1............................. 793 19,282 109,899,275 3,013,827 16,172 1,979 1,080 907
Martin Lake Unit 2............................. 793 17,167 109,899,275 3,013,827 14,101 2,270 1,238 1,040
Martin Lake Unit 3............................. 793 19,749 109,899,275 3,013,827 16,458 1,945 1,061 891
San Miguel Unit 1.............................. 410 12,006 56,820,558 1,558,221 2,001 8,270 4,512 3,791
Oklaunion Unit 1............................... 720 2,191 99,782,444 2,736,387 1,826 15,913 8,682 7,295
--------------------------------------------------------------------------------------------------------------------------------------------------------

Table 10-Texas's Cost Estimates of NOX Controls Oklaunion Unit 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
NOX 5-Year life 15-Year life 30-Year life
baseline Control NOX cost- cost- cost-
Source emissions Control efficiency reduction effectiveness effectiveness effectiveness
(tons/yr) (%) (tons/yr) ($/ton) ($/ton) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Oklaunion Unit 1.................... 6,804 SNCR.................... 50 3,402 $4,705 $4,152 $4,046
SCR..................... 98 6,668 11,222 6,455 5,541
--------------------------------------------------------------------------------------------------------------------------------------------------------

Table 11--Texas's Cost Estimate of SO2 Wet Scrubber Upgrades for Midlothian Plant
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline SO2 SO2 reduction Cost-effectiveness ($/ton)
SO2 control Annual due to scrubber -----------------------------
baseline efficiency Capital cost operating and upgrade at 95%
Unit emissions of wet ($) maintenance control 5-Year 15-Year 30-Year
(tons/yr) scrubber (%) costs ($) efficiency (tons/ life life life
yr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cement Kiln No 1............................... 522 90 8,196,683 224,782 261 $9,138 $4,986 $4,189
Cement Kiln No 2............................... 856 90 8,300,438 227,627 428 5,647 3,081 2,589
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 83359]]

Table 12--Texas's Cost Estimate of Tri-Mer Cat Controls for Vitro Flat Glass Works No 4 Plant
--------------------------------------------------------------------------------------------------------------------------------------------------------
Control 5-Year life 15-Year life 30-Year life
Baseline efficiency Emissions cost- cost- cost-
Unit Pollutant evaluated emissions evaluated reduction effectiveness effectiveness effectiveness
(tons/yr) (%) (tons/yr) ($/ton) ($/ton) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Glass Melting Furnace Line No.1... SO2...................... 136 80 109 $15,100 $10,300 $9,400
NOX...................... 674 80 539 15,100 10,300 9,400
Glass Melting Furnace Line No. 2.. SO2...................... 301 80 241 4,600 3,200 2,900
NOX...................... 2,533 80 2,026 4,600 3,200 2,900
--------------------------------------------------------------------------------------------------------------------------------------------------------

Table 13--Texas's Cost Estimates of NOX Controls for Graphic Packaging Texarkana Mill
--------------------------------------------------------------------------------------------------------------------------------------------------------
NOX 5-Year life 15-Year life 30-Year life
baseline Control NOX cost- cost- cost-
Unit emissions Control efficiency reduction effectiveness effectiveness effectiveness
(tons/yr) (%) (tons/yr) ($/ton) ($/ton) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Power Boiler No 1................... 109 LNB..................... 40 44 $21,788 $10,859 $8,762
SCR..................... 80 87 36,200 26,350 24,469
Power Boiler No 2................... 692 LNB..................... 40 277 3,525 1,757 1,417
SCR..................... 80 554 7,100 5,254 4,956
Recovery Boiler/Furnace No 1........ 275 LNB..................... 40 110 7,438 3,707 2,991
SCR..................... 80 220 11,800 9,248 8,755
Recovery Boiler/Furnace No 2........ 674 LNB..................... 40 270 3,619 1,804 1,455
SCR..................... 80 539 7,000 5,395 5,089
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Table 14--Texas's Cost Estimates of NOX Controls for El Paso Natural Gas Company Keystone Compressor Station
--------------------------------------------------------------------------------------------------------------------------------------------------------
NOX 5-Year life 15-Year life 30-Year life
baseline Control NOX cost- cost- cost-
Unit emissions Control efficiency reduction effectiveness effectiveness effectiveness
(tons/yr) (%) (tons/yr) ($/ton) ($/ton) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Reciprocating Internal Combustion 131 LEC..................... 40 53 $1,091 $544 $439
Engine, A01. SCR..................... 80 105 7,956 6,754 6,523
Reciprocating Internal Combustion 7 LEC..................... 40 3 19,209 9,573 7,724
Engine, A02. SCR..................... 80 6 129,200 108,036 103,974
Reciprocating Internal Combustion 133 LEC..................... 40 53 1,078 537 433
Engine, A03. SCR..................... 80 106 7,900 6,677 6,449
Reciprocating Internal Combustion 14 LEC..................... 40 6 9,989 4,978 4,017
Engine, A04. SCR..................... 80 11 67,500 56,494 54,381
Reciprocating Internal Combustion 24 LEC..................... 40 10 5,964 2,972 2,398
Engine, A05. SCR..................... 80 19 40,600 33,990 32,729
Reciprocating Internal Combustion 17 LEC..................... 40 7 8,664 4,318 3,484
Engine, A06. SCR..................... 80 13 58,600 49,085 47,253
Reciprocating Internal Combustion 14 LEC..................... 40 6 10,278 5,122 4,133
Engine, A07. SCR..................... 80 11 69,400 58,102 55,928
Reciprocating Internal Combustion 18 LEC..................... 40 12 4,851 2,418 1,915
Engine, A08. SCR..................... 80 24 33,100 27,769 26,743
Reciprocating Internal Combustion 16 LEC..................... 40 6 9,154 4,562 3,681
Engine, A09. SCR..................... 80 13 61,900 51,821 49,885
Reciprocating Internal Combustion 60 LEC..................... 40 24 2,377 1,185 956
Engine, A10. SCR..................... 80 48 16,600 13,940 13,437
Reciprocating Internal Combustion 34 LEC..................... 40 14 4,178 2,083 1,680
Engine, A11. SCR..................... 80 27 28,600 24,011 23,127
Reciprocating Internal Combustion 8 LEC..................... 40 3 18,554 9,247 7,461
Engine, A12. SCR..................... 80 6 124,800 104,367 100,443
Reciprocating Internal Combustion 29 LEC..................... 40 12 6,727 3,353 2,705
Engine, B01. SCR..................... 80 23 39,100 32,227 30,914
Reciprocating Internal Combustion 83 LEC..................... 40 33 2,365 1,179 951
Engine, B02. SCR..................... 80 66 14,200 11,755 11,293
Reciprocating Internal Combustion 66 LEC..................... 40 26 2,958 1,474 1,189
Engine, B03. SCR..................... 80 53 17,600 14,543 13,965
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Table 15--Texas's Cost Estimates of NOX Controls for El Paso Natural Gas Company Cornudas Plant
--------------------------------------------------------------------------------------------------------------------------------------------------------
NOX 5-Year life 15-Year life 30-Year life
baseline Control NOX cost- cost- cost-
Unit emissions Control efficiency reduction effectiveness effectiveness effectiveness
(tons/yr) (%) (tons/yr) ($/ton) ($/ton) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gas Turbine, A1..................... 69 LNB..................... 40 28 $1,913 $954 $769
SCR..................... 80 55 27,700 21,972 20,879
Gas Turbine, A2..................... 50 LNB..................... 40 20 5,823 2,902 2,341
SCR..................... 80 40 37,742 29,958 28,464
Gas Turbine, A3..................... 63 LNB..................... 40 25 4,623 2,304 1,859
SCR..................... 80 51 30,292 24,112 22,926
Gas Turbine, B1..................... 104 LNB..................... 40 42 3,748 1,868 1,507
SCR..................... 80 83 22,878 17,982 17,042
Gas Turbine, C1..................... 18 SCR..................... 80 14 129,955 101,694 96,270

[[Page 83360]]

Gas Turbine, C2..................... 18 SCR..................... 80 14 129,955 101,694 96,270
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Table 16--Texas's Cost Estimates of NOX Controls for El Paso Natural Gas Company Guadalupe Compressor Station
--------------------------------------------------------------------------------------------------------------------------------------------------------
NOX 5-Year life 15-Year life 30-Year life
baseline Control NOX cost- cost- cost-
Unit emissions Control efficiency reduction effectiveness effectiveness effectiveness
(tons/yr) (%) (tons/yr) ($/ton) ($/ton) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gas Turbine, C-1.................... 56 LNB..................... 40 23 $13,897 $6,926 $5,588
SCR..................... 80 45 69,485 54,975 52,190
--------------------------------------------------------------------------------------------------------------------------------------------------------

Table 17--Texas's Cost Estimates of NOX Controls for GCC Permian Odessa Cement Plant
--------------------------------------------------------------------------------------------------------------------------------------------------------
NOX 5-Year life 15-Year life 30-Year life
baseline Control NOX cost- cost- cost-
Unit emissions Control efficiency reduction effectiveness effectiveness effectiveness
(tons/yr) (%) (tons/yr) ($/ton) ($/ton) ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cement Kiln No 2.................... 427 LNB..................... 40 171 $3,163 $1,576 $1,272
--------------------------------------------------------------------------------------------------------------------------------------------------------

i. Texas Did Not Adequately Document the Technical Basis and Cost
Information on Which It Based Its Cost of Compliance Analyses as
Required by the Regional Haze Rule
Texas did not adequately document the technical basis and cost
information on which it based its evaluation of the cost of compliance
for all control measures considered as required by the Regional Haze
Rule.\155\ The SIP submittal discusses Texas's general approach for
estimating the cost of the various control options considered, but only
provides sum total estimates of the capital costs and annual operating
and maintenance costs without providing individual line items or
calculations for review. Texas received comments during the State's
public comment period on the proposed Texas RH SIP for the second
planning period stating that the proposed SIP did not include proper
documentation of the cost estimates of the various control measures,
including the actual spreadsheets showing the calculations that inform
the results of the cost analyses as part of the TCEQ's four-factor
analysis.\156\ Despite these comments, Texas did not directly address
why calculation spreadsheets and other necessary documentation of the
cost analysis were omitted from the proposed SIP, nor did Texas make
changes to the final SIP submittal or include adequate documentation of
the cost analysis in the final SIP submittal in response to these
comments. With respect to the capital and annual costs of scrubber
upgrades, Texas provided one additional piece of information in its
response stating that it relied on prior studies and work conducted on
potential scrubbing system upgrades to estimate the capital and annual
costs to inform total annualized costs.\157\ However, the response does
not explain what ``prior studies and work conducted on potential
scrubbing system upgrades'' it relied on or how it relied on those
studies to estimate the capital and annual cost of scrubber upgrades.
This documentation is critical to ensuring that Texas's consideration
of cost of potential control measures, as required by the RHR and the
CAA,\158\ was reasonable and based on sufficiently reliable
information.\159\
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\155\ 40 CFR 51.308(f)(2)(iii).
\156\ 2021 Texas Regional Haze Plan, Response to Comments at
478-479 of 653.
\157\ 2021 Texas Regional Haze Plan, Response to Comments at 479
of 653.
\158\ See 40 CFR 51.308(f)(2)(i) (``The State must evaluate and
determine the emission reduction measures that are necessary to make
reasonable progress by considering the costs of compliance . . .'');
CAA 169A(g)(1) (``in determining reasonable progress, there shall be
taken into consideration the costs of compliance . . .'').
\159\ As discussed in the following section, the EPA requested
the additional supporting information from Texas. In response, Texas
provided additional files and spreadsheets to EPA upon request.
However, the public did not have access to these files during the
state-level comment period and therefore did not have an opportunity
to review or comment on the complete technical basis of Texas's cost
analyses.
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The EPA has recommended that costs of compliance and the remaining
useful life should be calculated consistent with the methods set forth
in the EPA's Control Cost Manual in order to allow for comparisons
between different sources within a State, and cost analyses in other
states.\160\ To that end, states relying on EPA's Control Cost Manual
need only reference the manual as the documentation necessary to meet
the requirements of the RHR to document the technical basis, including
cost information, on which the State is relying.\161\ When a State uses
cost methods other than the EPA's Control Cost Manual, it is necessary
for those differences to be reasonable and sufficiently documented to
meet the requirements of the RHR to document the technical basis,
including cost information, on which the State is rely

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