[Federal Register Volume 88, Number 142 (Wednesday, July 26, 2023)]
[Proposed Rules]
[Pages 48152-48179]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-15338]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2014-0754; FRL-10412-01-R6]


Disapproval and Promulgation of Air Quality Implementation Plans; 
Texas and Oklahoma; Regional Haze State Implementation Plans; Federal 
Implementation Plan for Regional Haze; Completion of Remand

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: Pursuant to the Federal Clean Air Act (CAA or Act), the

[[Page 48153]]

Environmental Protection Agency (EPA) is proposing this action to 
address the voluntary remand of portions of a final rulemaking 
published in the Federal Register on January 5, 2016, addressing 
regional haze obligations for the first planning period in Texas and 
Oklahoma. Specifically, we are revisiting and again proposing 
disapproval of portions of the Texas Regional Haze State Implementation 
Plan (SIP) submission and portions of the Oklahoma Regional Haze SIP 
submission that relate to reasonable progress requirements for the 
first planning period from 2008 through 2018. We are also proposing to 
rescind the sulfur dioxide (SO2) emission limitations we 
promulgated as part of the Federal Implementation Plan (FIP) in the 
January 2016 Final Rule for 15 Texas electric generating units (EGUs) 
at eight facilities. We are proposing to determine that no additional 
controls are required for Texas or Oklahoma sources under these States' 
long-term strategies for making reasonable progress for the first 
planning period. We are leaving the portions of the Texas and Oklahoma 
Regional Haze SIPs that we approved in the January 2016 Final Rule in 
place and not reopening those determinations in this action.

DATES: 
    Comments: Comments must be received on or before September 25, 
2023.
    Virtual Public hearing: The EPA will hold a virtual public hearing 
to solicit comments on August 10, 2023. The last day to pre-register to 
speak at the hearing will be on August 8, 2023. On August 9, 2023, the 
EPA will post a general agenda for the hearing that will list pre-
registered speakers in approximate order at https://www.epa.gov/tx/texas-and-oklahoma-regional-haze-sip-disapproval-and-revision-regional-haze-federal. If you require the services of a translator or a special 
accommodation such as audio description/closed captioning, please pre-
register for the hearing and describe your needs by August 2, 2023.
    For more information on the virtual public hearing, see 
SUPPLEMENTARY INFORMATION.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R06-
OAR-2014-0754 to the Federal eRulemaking Portal: https://www.regulations.gov/ (our preferred method). For additional submission 
methods, please contact the person identified in the FOR FURTHER 
INFORMATION CONTACT section.
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov/, including any personal information 
provided.
    Docket: The docket for this action is available electronically at 
https://www.regulations.gov/. Some information in the docket may not be 
publicly available via the online docket due to docket file size 
restrictions, or content (e.g., CBI). For questions about a document in 
the docket please contact the individual listed in the FOR FURTHER 
INFORMATION CONTACT section.
    CBI: Do not submit information containing CBI to the EPA through 
https://www.regulations.gov/. To submit information claimed as CBI, 
please contact the individual listed in the FOR FURTHER INFORMATION 
CONTACT section. Clearly mark the part or all of the information that 
you claim to be CBI. In addition to one complete version of the 
comments that includes information claimed as CBI, you must submit a 
copy of the comments that does not contain the information claimed as 
CBI directly to the public docket through the procedures outlined in 
Instructions earlier. Information not marked as CBI will be included in 
the public docket and the EPA's electronic public docket without prior 
notice. Information marked as CBI will not be disclosed except in 
accordance with procedures set forth in 40 Code of Federal Regulations 
(CFR) part 2. For the full EPA public comment policy, information about 
CBI or multimedia submissions, and general guidance on making effective 
comments, please visit https://www2.epa.gov/dockets/commenting-epa-dockets.
    To pre-register to attend or speak at the virtual public hearing, 
please use the online registration form available at https://www.epa.gov/tx/texas-and-oklahoma-regional-haze-sip-disapproval-and-revision-regional-haze-federal or contact us via email at 
[email protected]. For more information on the virtual 
public hearing, see SUPPLEMENTARY INFORMATION.

FOR FURTHER INFORMATION CONTACT: Michael Feldman, Air and Radiation 
Division, SO2 and Regional Haze Section (ARSH), 
Environmental Protection Agency, 1201 Elm Street, Suite 500, Dallas, 
Texas 75270; telephone number: 214-665-9793; or via email: 
[email protected].

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

Virtual Public Hearing

    The EPA is holding a virtual public hearing to provide interested 
parties the opportunity to present data, views, or arguments concerning 
the proposal. The EPA will hold a virtual public hearing to solicit 
comments on August 10, 2023. The hearing will convene at 3:00 p.m. 
Central Time (CT) with a 15-minute break from 5:00 to 5:15 p.m. CT. The 
hearing will conclude at 7:00 p.m. CT, or 15 minutes after the last 
pre-registered presenter in attendance has presented if there are no 
additional presenters. The EPA will announce further details, including 
information on how to register for the virtual public hearing, on the 
virtual public hearing website at https://www.epa.gov/tx/texas-and-oklahoma-regional-haze-sip-disapproval-and-revision-regional-haze-federal. The EPA will begin pre-registering speakers and attendees for 
the hearing upon publication of this document in the Federal Register. 
To pre-register to attend or speak at the virtual public hearing, 
please use the online registration form available at https://www.epa.gov/tx/texas-and-oklahoma-regional-haze-sip-disapproval-and-revision-regional-haze-federal or contact us via email at 
[email protected]. The last day to pre-register to speak 
at the hearing will be on August 8, 2023. On August 9, 2023, the EPA 
will post a general agenda for the hearing that will list pre-
registered speakers in approximate order at https://www.epa.gov/tx/texas-and-oklahoma-regional-haze-sip-disapproval-and-revision-regional-haze-federal. Additionally, requests to speak will be taken on the day 
of the hearing as time allows.
    The EPA will make every effort to follow the schedule as closely as 
possible on the day of the hearing; however, please plan for the 
hearing to run either ahead of schedule or behind schedule. Each 
commenter will have approximately 3 to 5 minutes to provide oral 
testimony. The EPA encourages commenters to provide the EPA with a copy 
of their oral testimony electronically by including it in the 
registration form or emailing it to [email protected]. 
The EPA may ask clarifying questions during the oral presentations but 
will not respond to the presentations at that time. Written statements 
and supporting information submitted during the comment period will be 
considered with the same weight as oral comments and supporting 
information presented at the virtual public hearing. A transcript of 
the virtual public hearing, as well as

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copies of oral presentations submitted to the EPA, will be included in 
the docket for this action.
    The EPA is asking all hearing attendees to pre-register, even those 
who do not intend to speak. The EPA will send information on how to 
join the public hearing to pre-registered attendees and speakers.
    Please note that any updates made to any aspect of the hearing will 
be posted online at https://www.epa.gov/tx/texas-and-oklahoma-regional-haze-sip-disapproval-and-revision-regional-haze-federal. While the EPA 
expects the hearing to go forward as set forth above, please monitor 
our website or contact us via email at [email protected] 
to determine if there are any updates. The EPA does not intend to 
publish a document in the Federal Register announcing updates.
    If you require the services of a translator or a special 
accommodation such as audio description/closed captioning, please pre-
register for the hearing and describe your needs by August 2, 2023. The 
EPA may not be able to arrange accommodations without advance notice.

Table of Contents

I. Executive Summary
II. Background
    A. Regional Haze
    1. Determination of Baseline, Natural, and Current Visibility 
Conditions
    2. Reasonable Progress Requirements
    3. Long-Term Strategy (LTS)
    B. Previous Actions Related to Texas and Oklahoma Regional Haze 
Reasonable Progress Requirements for the First Planning Period
    C. Litigation, Stay Order, and EPA's Motion for Voluntary Remand
    D. Federal Land Manager (FLM) Consultation
III. Overview of Proposed Actions
IV. Legal Authority for This Action
V. EPA's Review of the 2016 Prior Disapprovals on Remand
    A. Proposal To Incorporate Our Prior Bases for Disapprovals
    B. Supplemental Bases for Our Disapproval of Texas's Four-Factor 
Analysis
    1. Selection of Sources for Evaluation in Four-Factor Analysis
    a. Texas's Cost-Effectiveness Threshold
    b. Scrubber Upgrades
    2. Consideration of the Four Factors
    a. Texas's Assumptions of SO2 Control Efficiency of 
Scrubbers
    b. Texas's Cost of Compliance Analysis Assumed Future CAIR 
Reductions as a Baseline
    3. Weighing of the Four Statutory Factors and Visibility 
Benefits
    a. Cost of Compliance
    b. Texas's Approach in Grouping Sources
    c. Texas's Evaluation of Potential Visibility Improvements
    i. Texas's Use of Visibility Thresholds
    ii. Visibility Benefits of Texas's Estimated Control Set
    iii. Texas's Use of Degraded Background Conditions
    d. Texas's ``Order of Magnitude Estimate'' for Visibility 
Improvement
    C. Clarification of Our Basis for Disapproval of Texas's 
Calculation of Natural Visibility Conditions
    D. Clarification of our Basis for Disapproval of Consultation 
Between Texas and Oklahoma
VI. Amending the FIP on Remand
VII. Proposed Action
VIII. Environmental Justice Considerations
IX. Impact on Areas of Indian Country
X. Statutory and Executive Order Reviews

I. Executive Summary

    The CAA's visibility protection program was created in response to 
a national goal set by Congress in 1977 to remedy and prevent 
visibility impairment in certain national parks, such as Big Bend, and 
national wilderness areas, such as the Wichita Mountains Wilderness. 
Vistas in these areas (referred to as Class I areas) are often obscured 
by visibility impairment such as regional haze, which is caused by 
emissions from numerous sources located over a wide geographic area.
    In response to this Congressional directive, the EPA promulgated 
regulations to address visibility impairment in 1999. These 
regulations, which are commonly referred to as the Regional Haze Rule 
(RHR), established an iterative process for achieving Congress's 
national goal by providing for multiple, approximately 10-year 
``planning periods'' in which state air agencies must submit to EPA 
plans that address sources of visibility-impairing pollution in their 
states. The first state plans were due in 2007 for the planning period 
that ended in 2018. The second state plans were due in 2021 for the 
period that ends in 2028. This proposal focuses on obligations from the 
first planning period of the regional haze program.
    The CAA and RHR require States to submit a long-term strategy that 
includes such measures as are necessary to achieve reasonable progress 
for each Class I area. A central element of the long-term strategy for 
the first planning period state plans was the requirement for certain 
older stationary sources to install the Best Available Retrofit 
Technology (BART) for the purpose of making reasonable progress towards 
Congress's national goal of eliminating visibility impairment within 
our nation's most treasured lands. The other central element of a 
state's long-term strategy is the requirement to include any additional 
control measures that are necessary to make ``reasonable progress'' 
towards the national goal. To determine what control measures are 
necessary to make reasonable progress and therefore must be included in 
the long-term strategy, states must consider four statutory factors: 
(1) the costs of compliance, (2) the time necessary for compliance, (3) 
the energy and nonair quality environmental impacts of compliance, and 
(4) the remaining useful life of any existing source subject to such 
requirements. This statutory requirement is often referred to as a 
``four-factor analysis.'' Additionally, when visibility-impairing 
emissions from multiple states impact the same national park or 
wilderness area, the RHR requires those states to coordinate and 
consult with one another to ensure that each state is making reasonable 
progress toward the national goal.
    Texas is home to numerous power plants and industrial sources, many 
of which operate without modern pollution controls. As a result, 
several of these plants are among the highest emitters of visibility-
impairing pollutants, such as sulfur dioxide (SO2), in the 
nation. These emissions cause or contribute to visibility impairment in 
such iconic places as Big Bend National Park (Big Bend) and Guadalupe 
Mountains National Park (Guadalupe Mountains) in Texas, and Wichita 
Mountains Wilderness Area (Wichita Mountains) in Oklahoma. To address 
this visibility impairment, Texas submitted its first regional haze 
state implementation plan (SIP) in 2009. After reviewing the SIP, the 
EPA determined that Texas did not analyze and weigh the four statutory 
factors in a reasonable way such that the SIP did not provide for 
reasonable progress towards eliminating visibility-impairing pollutants 
at these national parks and wilderness areas. Additionally, the EPA 
determined that Oklahoma and Texas did not adequately justify why 
additional reductions from Texas's sources were not necessary to 
address impacts at the Wichita Mountains as part of the consultation 
process required under the RHR despite information showing that impacts 
from Texas's sources were several times greater than the impact from 
Oklahoma's own sources. Therefore, in 2016, the EPA promulgated a final 
rule disapproving these portions of Texas's SIP and Oklahoma's SIP 
(while approving other aspects of both SIPs). The partial disapprovals 
triggered the requirement under the CAA for the EPA to promulgate a 
federal implementation plan (FIP) to remedy the deficiencies in the 
SIPs. Consequently, in the same action, EPA finalized a FIP that 
required

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cost-effective emissions control technologies that would have resulted 
in improved visibility at the Class I areas impacted by sources in 
Texas. However, Texas and several industry groups filed a petition for 
review challenging the final rule in the Fifth Circuit where they 
obtained a stay that prevented the rule from taking effect.
    In response to the Fifth Circuit motion panel's non-binding stay 
opinion, the EPA sought and received a voluntary remand of portions of 
the final rule to reconsider its action. After considering the non-
binding stay opinion and other relevant facts, the EPA is again 
proposing to disapprove the portions of the Texas and Oklahoma Regional 
Haze SIPs that the Agency disapproved in 2016. The EPA is also 
proposing to amend the FIP to account for recent developments, such as 
the retirements of previously covered sources and the EPA's recently 
proposed action to address the BART requirements for Texas's power 
plants, which, if finalized as proposed, would reduce SO2 
emissions in Texas by more than 80,000 tons per year (tpy), improving 
visibility across a wide range of scenic vistas in both Texas and 
nearby states. Based on these developments, the EPA proposes to 
determine that no additional controls are necessary to make reasonable 
progress for the first planning period, which ended in 2018.
    It has been 14 years since Texas submitted its first planning 
period Regional Haze SIP to EPA for review. Since that time, the first 
planning period ended, the second planning period began, and Texas 
submitted its Regional Haze SIP for the second planning period. Texas 
remains one of the few states in the nation that does not have a 
complete first planning period regional haze plan in place to protect 
the national parks and wilderness areas impacted by sources within the 
state. With this action, while also taking into consideration various 
power plant shutdowns in Texas and the recently proposed BART action, 
the EPA is proposing to find that the requirements for the first 
planning period are fulfilled. In a separate future action, EPA will 
evaluate Texas's second planning period Regional Haze SIP to determine 
whether that SIP satisfies the relevant statutory and regulatory 
requirements.

II. Background

A. Regional Haze

    Regional haze is visibility impairment that is produced by a 
multitude of sources and activities which are located across a broad 
geographic area. These sources and activities emit fine particulate 
matter (PM2.5) (e.g., sulfates, nitrates, organic carbon, 
elemental carbon, and soil dust) and its precursors (e.g., 
SO2, nitrogen oxides (NOX), and, in some cases, 
ammonia (NH3) and volatile organic compounds (VOCs)). Fine 
particle precursors react in the atmosphere to form PM2.5, 
which, in addition to direct sources of PM2.5, impairs 
visibility by scattering and absorbing light. Visibility impairment 
(i.e., light scattering) reduces the clarity, color, and visible 
distance that one can see.
    In section 169A of the 1977 Amendments to the Clean Air Act (CAA), 
Congress created a program for protecting visibility in the nation's 
national parks and wilderness areas. This section of the CAA 
establishes as a national goal the prevention of any future, and the 
remedying of any existing, anthropogenic (manmade) impairment of 
visibility in 156 national parks and wilderness areas designated as 
mandatory Class I areas.\1\ Congress added section 169B to the CAA in 
1990 to address regional haze issues, and the EPA promulgated the 
Regional Haze Rule (RHR), codified at 40 CFR 51.308,\2\ on July 1, 
1999.\3\ The RHR established a requirement for all States to submit a 
regional haze SIP, including the District of Columbia, and the Virgin 
Islands.\4\
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    \1\ Areas designated as mandatory Class I areas consist of 
National Parks exceeding 6,000 acres, wilderness areas and national 
memorial parks exceeding 5,000 acres, and all international parks 
that were in existence on August 7, 1977. 42 U.S.C. 7472(a). In 
accordance with section 169A of the CAA, EPA, in consultation with 
the Department of Interior, promulgated a list of 156 areas where 
visibility is identified as an important value. 44 FR 69122 
(November 30, 1979). The extent of a mandatory Class I area includes 
subsequent changes in boundaries, such as park expansions. 42 U.S.C. 
7472(a). Although states and tribes may designate as Class I 
additional areas which they consider to have visibility as an 
important value, the requirements of the visibility program set 
forth in section 169A of the CAA apply only to ``mandatory Class I 
Federal areas.'' Each mandatory Class I Federal area is the 
responsibility of a ``Federal Land Manager.'' 42 U.S.C. 7602(i). 
When we use the term ``Class I area'' in this action, we mean a 
``mandatory Class I Federal area.''
    \2\ In addition to the generally applicable regional haze 
provisions at 40 CFR 51.308, EPA also promulgated regulations 
specific to addressing regional haze visibility impairment in Class 
I areas on the Colorado Plateau at 40 CFR 51.309. The latter 
regulations are not relevant here.
    \3\ See 64 FR 35714 (July 1, 1999). On January 10, 2017, EPA 
promulgated revisions to the Regional Haze Rule that apply for the 
second and subsequent implementation periods. See 82 FR 3078 (Jan. 
10, 2017).
    \4\ 40 CFR 51.300(b).
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    To address regional haze visibility impairment, the RHR established 
an iterative planning process that requires States to periodically 
submit SIP revisions (each periodic revision referred to as a 
``planning period'') to address regional haze visibility impairment at 
Class I areas.\5\ Under the CAA, each SIP submission must contain ``a 
long-term (ten to fifteen years) strategy for making reasonable 
progress toward meeting the national goal,'' and the initial round of 
SIP submissions also had to address the statutory requirement that 
certain older, larger sources of visibility-impairing pollutants 
install and operate Best Available Retrofit Technology (BART).\6\ 
States' first regional haze SIPs were due by December 17, 2007, with 
subsequent SIP submissions containing revised long-term strategies 
originally due July 31, 2018, and every ten years thereafter.\7\ This 
action addresses first planning period reasonable progress 
requirements.\8\
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    \5\ See 42 U.S.C. 7491(b)(2); 40 CFR 51.308(b) and (f); see also 
64 FR at 35768. EPA established in the Regional Haze Rule that all 
states either have Class I areas within their borders or ``contain 
sources whose emissions are reasonably anticipated to contribute to 
regional haze in a Class I area;'' therefore, all states must submit 
regional haze SIPs. See 64 FR at 35721. In addition to each of the 
50 states, EPA also concluded that the Virgin Islands and District 
of Columbia contain a Class I area and/or contain sources whose 
emissions are reasonably anticipated to contribute regional haze in 
a Class I area. See 40 CFR 51.300(b) and (d)(3).
    \6\ See 42 U.S.C. 7491(b)(2)(A); 40 CFR 51.308(d) and (e).
    \7\ See 40 CFR 51.308(b). The 2017 Regional Haze Rule revisions 
changed the second period SIP due date from July 31, 2018, to July 
31, 2021, and maintained the existing schedules for the subsequent 
implementation periods. See 40 CFR 51.308(f).
    \8\ In a separate action, we proposed to withdraw the Texas 
SO2 Trading Program and proposed to address the 
SO2 and PM BART requirements for Texas BART eligible 
sources with source-specific SO2 and PM emission limits. 
See generally 88 FR 28918 (May 4, 2023).
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1. Determination of Baseline, Natural, and Current Visibility 
Conditions
    The Regional Haze Rule establishes the deciview (dv) as the 
principal metric for measuring visibility.\9\ This visibility metric 
expresses uniform changes in the degree of haze in terms of common 
increments across the entire range of visibility conditions, from 
pristine to extremely hazy conditions. Visibility is also sometimes 
expressed in terms of the visual range or light extinction. Visual 
range is the greatest distance, in kilometers or miles, at which a dark 
object can just be distinguished against the sky. Light extinction, 
expressed in units of inverse megameters (Mm-1), is the 
amount of light lost as it travels over distance. The haze index, in 
units of deciviews (dv), is calculated directly from the total light 
extinction. The deciview is a useful measure for tracking progress in 
improving

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visibility, because each deciview change is an equal incremental change 
in visibility perceived by the human eye. Most people can detect a 
change in visibility of one deciview.\10\
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    \9\ See 64 FR 35714, 35725-27 (July 1, 1999).
    \10\ The preamble to the Regional Haze Rule provides additional 
details about the deciview. 64 FR at 35725.
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    The deciview is used in expressing Reasonable Progress Goals (RPGs) 
(which are interim visibility goals towards meeting the national 
visibility goal), defining baseline, current, and natural conditions 
and tracking changes in visibility. The regional haze SIPs must contain 
measures that ensure ``reasonable progress'' toward the national goal 
of preventing and remedying visibility impairment in Class I areas 
caused by manmade air pollution by reducing anthropogenic emissions 
that cause regional haze.
    To track changes in visibility over time at each of the 156 Class I 
areas covered by the visibility program (40 CFR 81.401-437), and as 
part of the process for determining reasonable progress, states must 
calculate the degree of existing visibility impairment at each Class I 
area at the time of each regional haze SIP submittal and periodically 
review progress every five years midway through each 10-year 
implementation period. To do this, the RHR requirements for the first 
planning period \11\ provide that states must determine the degree of 
impairment (in deciviews) for the average of the 20 percent least 
impaired (``best'') and 20 percent most impaired (``worst'') visibility 
days over a specified time period at each of their Class I areas. In 
addition, states must also develop an estimate of natural visibility 
conditions for the purpose of comparing progress toward the national 
goal. Natural visibility is determined by estimating the natural 
concentrations of pollutants that cause visibility impairment and then 
calculating total light extinction based on those estimates. We have 
provided guidance to states regarding how to calculate baseline, 
natural, and current visibility conditions in the first planning 
period.\12\
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    \11\ The applicable requirements of the Regional Haze Rule for 
the first planning period are found in 40 CFR 51.308(d).
    \12\ Guidance for Estimating Natural Visibility Conditions Under 
the Regional Haze Rule, September 2003, EPA-454/B-03-005, available 
at https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20030901_oaqps_epa-454_b-03-005_estimating_natural%20_visibility_regional_haze.pdf (hereinafter 
referred to as ``our 2003 Natural Visibility Guidance''); and 
Guidance for Tracking Progress Under the Regional Haze Rule, EPA-
454/B-03-004, September 2003, available at https://www.epa.gov/sites/default/files/2021-03/documents/tracking.pdf (hereinafter 
referred to as our ``2003 Tracking Progress Guidance'').
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    For the regional haze SIPs for the first planning period, 
``baseline visibility conditions'' were the starting points for 
assessing ``current'' visibility impairment. Baseline visibility 
conditions represent the degree of visibility impairment for the 20 
percent least impaired days and 20 percent most impaired days for each 
calendar year from 2000 to 2004. Using monitoring data for 2000 through 
2004, states are required to calculate the average degree of visibility 
impairment for each Class I area on the 20 percent least and most 
impaired days, based on the average of annual values over the five-year 
period. The comparison of initial baseline visibility conditions to 
natural visibility conditions indicates the amount of improvement 
necessary to attain natural visibility, while the future comparison of 
baseline conditions to the then current conditions will indicate the 
amount of progress made. In general, the 2000-2004 baseline period is 
considered the time from which improvement in visibility is measured in 
the first planning period.
2. Reasonable Progress Requirements
    The vehicle for ensuring continuing progress towards achieving the 
natural visibility goal is the submission of a series of regional haze 
SIPs from the States that include a long-term strategy, as discussed in 
the subsection that follows, and establish two RPGs (i.e., one for the 
``best'' and one for the ``worst'' days) for each Class I area within 
the State for each (approximately) 10-year planning period.\13\ The 
Regional Haze Rule does not mandate specific milestones or rates of 
progress, but instead calls for States to establish goals that provide 
for ``reasonable progress'' toward achieving natural visibility 
conditions. In establishing RPGs, States must provide for an 
improvement in visibility for the most impaired days over the 
(approximately) 10-year period of the SIP and ensure no degradation in 
visibility for the least impaired days over the same period.\14\
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    \13\ See 64 FR at 35730-37.
    \14\ Id.
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    States have discretion in establishing RPGs for their Class I 
areas, but in doing so must consider the following factors established 
in section 169A of the CAA and in our Regional Haze Rule at 40 CFR 
51.308(d)(1)(i)(A): (1) The costs 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. States must demonstrate in their SIPs how 
they considered these four factors when establishing the RPGs for the 
best and worst days for each of their Class I areas. As noted in our 
Reasonable Progress Guidance for the first planning period, States have 
flexibility in how they take these factors into consideration, but must 
exercise that discretion in a manner consistent with the CAA and the 
Regional Haze Rule.\15\ In establishing the RPGs, States must also 
consider the rate of progress needed to reach natural visibility 
conditions by 2064 (referred to hereafter as the ``Uniform Rate of 
Progress (URP)'') and the emission reduction measures needed to achieve 
that rate of progress over the 10-year period of the SIP. Uniform 
progress towards achievement of natural conditions by the year 2064 
represents a rate of progress, which States are to use for analytical 
comparison to the amount of progress they expect to achieve. In 
establishing RPGs, each State with one or more Class I areas must also 
consult with potentially ``contributing states,'' i.e., other nearby 
states with emission sources that may be affecting visibility 
impairment at Class I areas.\16\
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    \15\ Guidance for Setting Reasonable Progress Goals under the 
Regional Haze Program, June 1, 2007, memorandum from William L. 
Wehrum, Acting Assistant Administrator for Air and Radiation, to EPA 
Regional Administrators, EPA Regions 1-10 (pp. 4-2, 5-1).
    \16\ 40 CFR 51.308(d)(1)(iv).
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3. Long-Term Strategy (LTS)
    Consistent with the requirement in section 169A(b) of the CAA that 
States include in their regional haze SIP a 10-to-15-year strategy for 
making reasonable progress, section 51.308(d)(3) of the Regional Haze 
Rule requires that States include a LTS that addresses regional haze 
visibility impairment for each mandatory Class I area within the State 
and for each mandatory Class I area located outside the State which may 
be affected by emissions from the State. The LTS in each implementation 
period is the compilation of all control measures a State has 
determined are necessary to make reasonable progress towards achieving 
natural visibility conditions. The LTS must include ``enforceable 
emissions limitations, compliance schedules, and other measures as 
necessary to achieve the reasonable progress goals'' for all Class I 
areas within, or affected by emissions from, the state.\17\
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    \17\ 40 CFR 51.308(d)(3).
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    When a State's emissions are reasonably anticipated to cause or 
contribute to visibility impairment in a Class I area located in 
another State, the Regional Haze Rule requires the

[[Page 48157]]

impacted state to coordinate with the contributing States in order to 
develop coordinated emissions management strategies.\18\ In such cases, 
the contributing State must demonstrate that it has included in its SIP 
submission all measures necessary to obtain its share of the emission 
reductions needed to meet the RPGs for the Class I area. A State must 
also consult with any State having emissions that are reasonably 
anticipated to contribute to visibility impairment in any of its 
mandatory Class I areas.\19\ Where other States cause or contribute to 
impairment in a mandatory Class I area, the State must demonstrate that 
it has included in its implementation plan all measures necessary to 
obtain its share of the emission reductions needed to meet the progress 
goal for the area.\20\ The State must document the technical basis on 
which the State is relying to determine its apportionment of emission 
reduction obligations necessary for achieving reasonable progress in 
each mandatory Class I area it affects.\21\ Regional planning 
organizations (RPOs) have provided forums for significant interstate 
consultation, but additional consultations between States may be 
required to sufficiently address interstate visibility issues. This is 
especially true where two States belong to different RPOs.
---------------------------------------------------------------------------

    \18\ 40 CFR 51.308(d)(3)(i).
    \19\ 40 CFR 51.308(d)(3)(i).
    \20\ 40 CFR 51.308(d)(3)(ii).
    \21\ 40 CFR 51.308(d)(3)(iii).
---------------------------------------------------------------------------

    States should consider all types of anthropogenic sources of 
visibility impairment in developing their LTS, including stationary, 
minor, mobile, and area sources.\22\ At a minimum, states must describe 
how each of the following seven factors listed below are taken into 
account in developing their LTS: (1) Emission reductions due to ongoing 
air pollution control programs, including measures to address 
``reasonably attributable visibility impairment'' (RAVI); (2) measures 
to mitigate the impacts of construction activities; (3) emissions 
limitations and schedules for compliance to achieve the RPG; (4) source 
retirement and replacement schedules; (5) smoke management techniques 
for agricultural and forestry management purposes including plans as 
currently exist within the State for these purposes; (6) enforceability 
of emissions limitations and control measures; (7) the anticipated net 
effect on visibility due to projected changes in point, area, and 
mobile source emissions over the period addressed by the LTS.\23\
---------------------------------------------------------------------------

    \22\ 40 CFR 51.308(d)(3)(iv).
    \23\ 40 CFR 51.308(d)(3)(v).
---------------------------------------------------------------------------

B. Previous Actions Related to Texas and Oklahoma Regional Haze 
Reasonable Progress Requirements for the First Planning Period

    On March 31, 2009, Texas submitted a regional haze SIP (the 2009 
Regional Haze SIP) to the EPA to address regional haze requirements for 
the first planning period. On December 16, 2014, we proposed an action 
to partially approve this SIP revision as meeting certain requirements 
of the regional haze program (2014 Proposed Rule).\24\ We also proposed 
to partially disapprove the Texas SIP revision for not adequately 
addressing other requirements of the regional haze program related to 
reasonable progress, the long-term strategy, and the calculation of 
natural visibility conditions. Given the large visibility impairment at 
Oklahoma's Class I area \25\ due to emissions from Texas and the 
requirements to develop emission control strategies in consultation 
with impacting States,\26\ we proposed in the same action to partially 
disapprove a revision to the Oklahoma SIP submitted on February 19, 
2010, which also addressed regional haze for the first planning 
period.\27\ We proposed a FIP for Texas and Oklahoma to remedy the 
deficiencies we identified in the SIPs.
---------------------------------------------------------------------------

    \24\ 79 FR 74818 (Dec. 16, 2014).
    \25\ Wichita Mountains is the only Class I area in Oklahoma. 40 
CFR 81.424.
    \26\ 79 FR at 74821-74822.
    \27\ Specifically, we proposed to disapprove the portion of the 
Oklahoma Regional Haze SIP that addresses the requirements of 
section 51.308(d)(1), except for section 51.308(d)(1)(vi). 79 FR 
74818 (Dec. 16, 2014).
---------------------------------------------------------------------------

    In January 2016, we took final action to partially approve and 
partially disapprove portions of Texas's 2009 Regional Haze SIP and 
Oklahoma's 2010 Regional Haze SIP (2016 Final Rule).\28\ We approved 
the Texas SIP revision as meeting certain requirements of the regional 
haze program, including BART requirements for facilities other than 
Electric Generating Units (EGUs).\29\ We disapproved Texas's RPGs for 
Big Bend and the Guadalupe Mountains and found that Texas did not 
satisfy several of the requirements of the Regional Haze Rule at 40 CFR 
51.308(d)(1) with regard to establishing RPGs, most notably the four-
factor analysis required under section 51.308(d)(1)(i)(A) and the 
requirement to adequately justify RPGs that are less stringent than the 
URP under section 51.308(d)(1)(ii). We disapproved Texas's calculation 
of natural visibility conditions for Big Bend and Guadalupe Mountains 
under section 51.308(d)(2)(iii) and other calculations that are 
dependent on the calculation of natural visibility conditions, 
including the calculation of the emission reductions needed to achieve 
the URP for these Class I areas under section 51.308(d)(1)(i)(B) and 
the calculation of the number of deciviews by which baseline conditions 
exceed natural visibility conditions under section 51.308(d)(2)(iv)(A). 
We also disapproved a majority of the portions of Texas's 2009 Regional 
Haze SIP that address the long-term strategy requirements under section 
51.308(d)(3), including the long-term strategy consultations with 
Oklahoma. In the 2016 Final Rule, we also disapproved Oklahoma's RPGs 
for the Wichita Mountains and disapproved the portions of the Oklahoma 
SIP addressing the requirements of section 51.308(d)(1) with regard to 
setting RPGs, with the exception of section 51.308(d)(1)(vi), which we 
approved.
---------------------------------------------------------------------------

    \28\ 81 FR 296 (Jan. 5, 2016).
    \29\ For EGU facilities, we addressed the BART requirements in a 
separate rulemaking in 2017 (and affirmed in 2020), which, in part, 
created the Texas SO2 Trading Program. See 82 FR 48324 
(October 17, 2017) and 85 FR 49170 (Aug.12, 2020). We recently 
proposed to withdraw the Texas SO2 Trading Program and 
proposed to replace the program with source-specific SO2 
emission limits for BART eligible sources. See generally 88 FR 28918 
(May 4, 2023). We are not addressing BART for Texas EGUs in this 
proposed rule.
---------------------------------------------------------------------------

    We also finalized a FIP for Texas and Oklahoma to remedy the 
deficiencies we identified in their SIPs (2016 FIP).\30\ The FIP 
included our own four factor analysis for Texas and implemented 
SO2 emission limits on fifteen Texas EGUs at eight different 
facilities as part of a long-term strategy for making reasonable 
progress at the Class I areas in Texas and Oklahoma; \31\ established 
revised natural conditions on the 20 percent best and worst days for 
the Guadalupe Mountains and Big Bend Class I areas; recalculated the 
number of deciviews by which baseline visibility conditions exceed 
natural visibility conditions for the Guadalupe Mountains and Big Bend 
Class I areas; and established new RPGs for the Big Bend, the Guadalupe 
Mountains, and Wichita Mountains Class I areas.\32\ The FIP did not 
establish any additional requirements on sources within Oklahoma.
---------------------------------------------------------------------------

    \30\ See 81 FR at 346-47.
    \31\ The Class I areas in Texas are Big Bend and Guadalupe 
Mountains. The Class I area in Oklahoma is Wichita Mountains.
    \32\ 81 FR at 346-47.

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

[[Page 48158]]

C. Litigation, Stay Order, and EPA's Motion for Voluntary Remand

    On March 1, 2016, the State of Texas, the Public Utility Commission 
of Texas, and the Texas Commission on Environmental Quality (Texas) 
filed a petition for review of the 2016 Final Rule in the United States 
Court of Appeals for the Fifth Circuit. Additional parties added as 
petitioners include Luminant Generation Company, L.L.C., and other 
Utilities.\33\ On March 28, 2016, the Court granted motions to 
intervene filed by IBEW Local Union 2337 in support of petitioners and 
by Sierra Club and National Parks Conservation Association (NPCA) in 
support of the EPA.\34\
---------------------------------------------------------------------------

    \33\ Other parties include: Big Brown Power Company, L.L.C.; 
Luminant Mining Company, L.L.C.; Big Brown Lignite Company, L.L.C.; 
Luminant Big Brown Mining Company, L.L.C.; Southwestern Public 
Service Company; Utility Air Regulatory Group; Coleto Creek Power, 
L.P.; NRG Texas Power, L.L.C.; and Nucor Corporation (Utilities).
    \34\ The Court combined all petitions under Case No. 16-60118.
---------------------------------------------------------------------------

    On March 3, 2016, and March 17, 2016, the Utilities and Texas 
respectively filed motions to stay the 2016 Final Rule in the Fifth 
Circuit. The EPA filed a response to these motions on April 7, 2016, 
and the Utilities and Texas filed separate reply briefs on April 18, 
2016. The motions panel rendered a non-binding opinion on July 15, 2016 
(2016 stay opinion), granting the stay and concluding, in part, that 
the Petitioners had demonstrated a strong likelihood of success on the 
merits.\35\
---------------------------------------------------------------------------

    \35\ Texas v. EPA, 829 F.3d 405, 411 (5th Cir. 2016).
---------------------------------------------------------------------------

    Regarding the EPA's disapproval of Texas's RPGs, the motions panel 
held that ``Petitioners are likely to establish that EPA improperly 
failed to defer to Texas's application of the statutory factors and 
improperly required a source-specific analysis not found in the Act or 
Regional Haze Rule.'' \36\ As to EPA's disapproval of the consultation 
between Texas and Oklahoma, the panel stated that ``EPA's disapproval 
seems to stem in large part from its assertion that Texas had to 
conduct a source-specific analysis and provide Oklahoma with that 
source-specific analysis.'' \37\ The panel found that, ``given the 
absence of a regulation or statute requiring source-specific 
consultations'' (among other things), the ``Petitioners have a strong 
likelihood of success in showing that EPA's disapproval of the 
consultation between Oklahoma and Texas was arbitrary and capricious.'' 
\38\
---------------------------------------------------------------------------

    \36\ Texas, 829 F. 3d at 428. Additionally, the Court noted that 
``other grounds for disapproval were asserted in the proposed rule 
but were not finalized in the Final Rule.''
    \37\ Texas, 829 F. 3d at 428.
    \38\ Texas, 829 F. 3d at 429.
---------------------------------------------------------------------------

    Regarding the FIP, the panel found that Petitioners had a strong 
likelihood of showing that EPA acted in excess of its statutory power 
when it imposed emission controls that would not be installed until 
after the period of time covered by the first planning period.\39\ The 
panel found that ``EPA bound states (and accordingly bound itself) to a 
ten-year window when it promulgated the Regional Haze Rule,'' and that 
the EPA does not have the authority to require actions that would take 
place after the particular period.\40\ Finally, the panel held that the 
``EPA's truncated discussion of [electric power] grid reliability 
indicates that the agency may not have fulfilled its statutory 
obligation to consider the energy impacts of the FIP.'' \41\
---------------------------------------------------------------------------

    \39\ Texas, 829 F. 3d at 430.
    \40\ Texas, 829 F. 3d at 430.
    \41\ Texas, 829 F. 3d at 433. Additionally, the court stated it 
did not need to consider whether EPA improperly used a dollars per 
ton of reduced pollution metric versus a dollars per deciview 
improvement metric ``or whether the costs imposed are unreasonable 
as a whole in light of the minimal visibility benefits the FIP would 
achieve in the relevant period,'' because petitioners have a strong 
likelihood of establishing other flaws in the FIP. Texas, 829 F. 3d 
at 431.
---------------------------------------------------------------------------

    The panel further found that petitioners had demonstrated that they 
would suffer irreparable injury if the effect of the 2016 Final Rule 
was not stayed pending litigation of the petition for review.\42\ 
Moreover, the panel found that a stay would not injure EPA or 
Intervenor-Respondents, and that ``the public's interest in ready 
access to affordable electricity outweighs the inconsequential 
visibility differences that the federal implementation plan would 
achieve in the near future.'' \43\ As such, the panel stayed the 2016 
Final Rule in its entirety, ``including the emissions control 
requirements, pending the outcome of this petition for review.'' \44\
---------------------------------------------------------------------------

    \42\ Texas, 829 F. 3d at 433-434.
    \43\ Texas, 829 F. 3d at 434-435.
    \44\ Texas, 829 F. 3d at 435.
---------------------------------------------------------------------------

    In addition to the panel's ruling, one of the petitioners, 
Luminant, submitted a request for administrative reconsideration of the 
2016 Final Rule pursuant to CAA section 307(d)(7)(B) on March 2, 
2016.\45\ Among other things, Luminant argued that reconsideration is 
appropriate because EPA did not finalize its proposal to rely on the 
Cross-State Air Pollution Rule (CSAPR) to satisfy BART for Texas EGUs, 
but nonetheless finalized the Agency's proposed long-term strategy and 
RPGs for Texas. Luminant argued that, ``by deferring this action, EPA 
is fundamentally changing the manner in which it will evaluate BART 
controls for Texas and how reasonable progress is evaluated.'' \46\
---------------------------------------------------------------------------

    \45\ Luminant Reconsideration (Exhibit A w/Remand Motion).
    \46\ Luminant Reconsideration (Exhibit A w/Remand Motion) at 2.
---------------------------------------------------------------------------

    On December 2, 2016, the EPA filed a motion for a partial voluntary 
remand of the portions of the 2016 Final Rule disapproving the Texas 
and Oklahoma SIPs and imposing FIPs.\47\ We stated that our concerns 
leading to our request for a voluntary remand are ``substantial and 
legitimate,'' as the court's order demonstrated that the 2016 Final 
Rule could be found arbitrary and capricious or contrary to law.\48\ We 
also stated that it was ``appropriate to reconsider the Final Rule, 
provide interested parties with a new opportunity to provide comment, 
including with respect to the views expressed in the Court's Order, and 
issue a new rule that takes into account the comments received on any 
factual circumstances that could warrant different outcomes.'' \49\ In 
response to the EPA's motion for partial voluntary remand, on March 22, 
2017, the court remanded the action to the EPA.
---------------------------------------------------------------------------

    \47\ Respondent's Motion for Partial Voluntary Remand, Texas v. 
EPA, Case No. 16-60118 (Dec. 2, 2016) (hereinafter referred to as 
``Remand Motion'').
    \48\ Citizens Against Pellissippi Parkway Extension, Inc. v. 
Mineta, 375 F.3d 412, 417 (6th Cir. 2004). Also, Remand Motion at 
21.
    \49\ Remand Motion at 21.
---------------------------------------------------------------------------

    Therefore, in this proposal, the EPA is revisiting its prior 
regional haze SIP disapprovals and FIPs on remand. This is more fully 
described in sections V and VI. Because the EPA's motion for remand was 
specific to the prior regional haze SIP disapprovals and FIPs, we are 
leaving our prior approvals in place and not reopening those 
determinations in this action.\50\ Additionally, while the EPA has not 
acted on Luminant's administrative

[[Page 48159]]

petition for reconsideration, at this time, we need not take a position 
on the issue Luminant raised in its petition. In the separate 2023 
Texas BART action, the EPA proposed BART controls for Texas EGUs, which 
we anticipate finalizing before finalizing this reasonable progress 
action.\51\ Once finalized, the Texas BART action should address 
Luminant's concern.
---------------------------------------------------------------------------

    \50\ The 2016 Final Rule also disapproved portions of the 
following Texas SIP submittals intended to address CAA provisions 
under section 110(a)(2)(D)(i)(II) that prohibit air pollutant 
emissions from interfering with measures required to protect 
visibility in any other state: April 4, 2008: 1997 8-hour Ozone and 
1997 PM2.5 (24-hour and annual); May 1, 2008: 1997 8-hour 
Ozone and 1997 PM2.5 (24-hour and annual); November 23, 
2009: 2006 24-hour PM2.5; December 7, 2012: 2010 
NO2; December 13, 2012: 2008 8-hour Ozone; and May 6, 
2013: 2010 1-hour SO2 National Ambient Air Quality 
Standards (NAAQS). In a proposed rule published on January 4, 2017 
(82 FR 912), we proposed to reconsider the basis of our prior 
disapproval and re-proposed disapproval of these portions of these 
Texas SIP submittals and our final disapproval was published on 
October 17, 2017 (82 FR 48324, 48332). We are not further addressing 
our disapproval of the interstate visibility transport portions of 
these Texas SIP submittals.
    \51\ See, Revision and Promulgation of Air Quality 
Implementation Plans; Texas; Regional Haze Federal Implementation 
Plan; Disapproval and Need for Error Correction; Denial of 
Reconsideration of Provisions Governing Alternative to Source-
Specific Best Available Retrofit Technology (BART) Determinations 88 
FR 28918 (May 4, 2023), Docket No. EPA-R06-OAR-2016-0611; EPA-HQ-
OAR-2016-0598.
---------------------------------------------------------------------------

D. Federal Land Manager (FLM) Consultation

    The RHR requires that a state, or the EPA if promulgating a FIP, 
consult with FLMs before adopting and submitting a required SIP or SIP 
revision or a required FIP or FIP revision. Under 40 CFR 51.308(i)(2), 
a state, or the EPA if promulgating a FIP, must provide an opportunity 
for consultation no less than 60 days prior to holding any public 
hearing or other public comment opportunity on a SIP or SIP revision, 
or FIP or FIP revision, for regional haze. The EPA must include a 
description of how it addressed comments provided by the FLMs when 
considering a FIP or FIP revision. We consulted with the FLMs 
(specifically, U.S. Fish and Wildlife Service, U.S. Forest Service, and 
the National Park Service) on April 12, 2023. During the consultation 
we provided an overview of our proposed actions. The FLMs signaled 
general support for our proposed action and did not provide any written 
comments.\52\
---------------------------------------------------------------------------

    \52\ See ``Texas Regional Haze FLM Consultation 4_12_23.xls'' in 
the docket for this action.
---------------------------------------------------------------------------

III. Overview of Proposed Actions

    To address the voluntary remand, we are proposing to disapprove the 
same portions of the Texas and Oklahoma SIPs we previously disapproved 
in 2016. For certain portions of these disapprovals, we are 
supplementing and clarifying our rationale for disapproval. For others, 
we are incorporating our original bases for disapproval as detailed in 
our 2014 Proposed Rule and 2016 Final Rule.
    We are proposing to supplement and clarify our disapproval of the 
portions of the Texas Regional Haze SIP that address several of the 
requirements at section 51.308(d)(1) related to establishing RPGs, most 
notably the four-factor analysis required under section 
51.308(d)(1)(i)(A) and the requirement to adequately justify RPGs that 
are less stringent than the URP under section 51.308(d)(1)(ii) based on 
the consideration of the four statutory factors in section 
51.308(d)(1)(i)(A). Additionally, we are proposing to supplement and 
clarify our disapprovals of the Texas Regional Haze SIP regarding 
natural visibility conditions and proposing to supplement and clarify 
our disapprovals of the consultation portions in the Regional Haze SIPs 
for Texas and Oklahoma.\53\
---------------------------------------------------------------------------

    \53\ See Section 51.308(d)(2)(iii) for requirements regarding 
natural visibility conditions; Sections 51.308(d)(3)(i) and 
51.308(d)(1)(iv) for the consultation requirements.
---------------------------------------------------------------------------

    For the remaining portions of the Texas Regional Haze SIP that we 
are proposing to disapprove, we are relying on the bases for 
disapproval that were discussed in the preambles of our 2014 Proposed 
Rule and 2016 Final Rule. Similarly, for those portions of the Oklahoma 
Regional Haze SIP that we are proposing to disapprove, we are relying 
on the bases for disapproval that were discussed in the preambles of 
our 2014 Proposed Rule and 2016 Final Rule. We do not reiterate in 
detail the bases for these disapprovals in this notice but rather refer 
the reader to the preambles of those prior rulemakings. See section 
V.A. for a detailed list of the portions of the Texas and Oklahoma 
Regional Haze SIPs for which we are proposing disapproval and 
incorporating our original bases for disapproval in this action.\54\
---------------------------------------------------------------------------

    \54\ See 79 FR 74818 (2014 Proposed Rule) and 81 FR 296 (2016 
Final Rule).
---------------------------------------------------------------------------

    We are proposing to amend the 2016 FIP to find that no further 
federal action is needed to remedy the proposed disapprovals of 
portions of the Texas and Oklahoma Regional Haze SIPs. Therefore, we 
are proposing to rescind the SO2 emission limits established 
in the 2016 Final Rule. Our proposal to rescind the SO2 
emission limitations and the associated monitoring, reporting, and 
recordkeeping requirements we established in the 2016 FIP is based on 
developments that occurred during the period between the 2016 Final 
Rule and this proposal, including the shutdown of several of the same 
units for which we promulgated emission limits in the 2016 Final Rule, 
our recently proposed SO2 BART emission limits on several of 
the same units for which we required controls in the 2016 Final Rule, 
and the portion of the Fifth Circuit's stay opinion pertaining to the 
imposition of controls beyond the end of the planning period. We also 
acknowledge the EPA's ability to consider the remaining units during 
our forthcoming review of Texas's Regional Haze SIP for the second 
planning period. We are also proposing to find that our rescission of 
the SO2 emission limitations and the associated monitoring, 
reporting, and recordkeeping requirements we established in the 2016 
FIP is consistent with CAA section 110(l). Specifically, we are 
proposing to find that our proposed rescission of the FIP would not 
interfere with any applicable requirement concerning attainment or 
reasonable further progress (as defined in section 7501 of this title), 
or any other applicable requirements of the CAA.

IV. Legal Authority for This Action

    The EPA has the authority to revisit its prior actions on SIPs and 
FIPs on remand. As previously stated, in light of the discussion 
regarding the likelihood of success on the merits set forth in the 
Fifth Circuit's 2016 stay order, EPA moved for partial voluntary remand 
of the SIP disapprovals and FIPs, without admitting error. The Fifth 
Circuit granted the motion and remanded the action to EPA on March 22, 
2017. Thus, EPA has an obligation to complete its action on remand.
    On remand, EPA is taking this action pursuant to CAA sections 
110(c)(1), 110(k)(3) and 169A(b)(2). CAA section 169A(b)(2) requires 
states to revise their SIPs to contain such measures as may be 
necessary to make reasonable progress towards the national visibility 
goal. Additionally, CAA section 110(k)(3) authorizes EPA to approve, 
disapprove, or partially approve and partially disapprove a SIP or SIP 
revision, and CAA section 110(c)(1) authorizes EPA to promulgate a FIP 
where ``the Administrator . . . disapproves a State implementation plan 
submission in whole or in part.'' EPA's authority to take such actions 
under the CAA necessarily provides it the inherent authority to revisit 
and amend such actions as necessary. See Trujillo v. Gen Elec. Co., 621 
F.2d 1084, 1086 (10th Cir. 1980). It is well established that agencies 
have inherent authority to revisit past decisions and to revise, 
replace, or repeal a decision to the extent permitted by law and 
supported by a reasoned explanation. FCC v. Fox Television Stations, 
Inc., 556 U.S. 502, 515 (2009); Motor Vehicle Manufacturers Ass'n of 
the United States, Inc. v. State Farm Mutual Automobile Insurance Co., 
463 U.S. 29, 42 (1983); see also Encino Motorcars, LLC v. Navarro, 579 
U.S. 211, 221-22 (2016). Further, the Fifth Circuit granted EPA's 
request for a voluntary remand and this action responds to that remand.

[[Page 48160]]

V. EPA's Review of the 2016 Prior Disapprovals on Remand

    In the 2016 Final Rule, we finalized our disapprovals of several 
portions of the Texas and Oklahoma Regional Haze SIPs. In this action, 
we are revisiting those prior disapprovals, and we are again proposing 
to disapprove those portions of the SIPs and provide supplemental 
rationale, where necessary, to support the proposed disapprovals.

A. Proposal To Incorporate Our Prior Bases for Disapprovals

    The specific portions of the Texas Regional Haze SIP we disapproved 
in the 2016 Final Rule are:
     Section 51.308(d)(1) regarding the RPGs for the Guadalupe 
Mountains and Big Bend;
     Section 51.308(d)(1)(i)(A) regarding the requirement to 
conduct a four-factor analysis;
     Section 51.308(d)(1)(i)(B) regarding the requirement to 
calculate the emission reduction measures needed to achieve the URP for 
the Guadalupe Mountains and Big Bend for the period covered by the SIP;
     Section 51.308(d)(1)(ii) regarding the requirement to 
demonstrate, based on the factors in Section 51.308(d)(1)(i)(A), that 
the progress goals adopted by Texas are reasonable;
     Section 51.308(d)(2)(iii) regarding the calculation of 
natural visibility conditions for the Guadalupe Mountains and Big Bend 
for the most impaired and least impaired days;
     Section 51.308(d)(2)(iv) regarding the calculation of the 
number of deciviews by which baseline conditions exceed natural 
visibility conditions for the Guadalupe Mountains and Big Bend for the 
most impaired and least impaired days;
     Section 51.308(d)(3)(i) regarding Texas's long-term 
strategy consultation with Oklahoma in order to develop coordinated 
emission management strategies to address visibility impacts at the 
Wichita Mountains;
     Section 51.308(d)(3)(ii) regarding the requirement for 
Texas to secure its share of reductions necessary to achieve the RPGs 
for the Guadalupe Mountains, Big Bend, and the Wichita Mountains;
     Section 51.308(d)(3)(iii) regarding the requirement for 
Texas to document the technical basis for its long-term strategy for 
the Guadalupe Mountains, Big Bend, and the Wichita Mountains;
     Section 51.308(d)(3)(v)(C) regarding Texas's emission 
limitations and schedules for compliance to achieve the RPGs for the 
Guadalupe Mountains, Big Bend, and the Wichita Mountains;
     30 Texas Administrative Code (TAC) 116.1510(d), which was 
incorporated into the Texas Regional Haze SIP and relied on the now 
defunct CAIR.
    The specific portions of the Oklahoma Regional Haze SIP we 
disapproved in the January 5, 2016 rulemaking are:
     Section 51.308(d)(1) regarding the RPGs for the Wichita 
Mountains;
     Section 51.308(d)(1)(i)(A) regarding the requirement to 
conduct a four-factor analysis;
     Section 51.308(d)(1)(i)(B) regarding the requirement to 
consider the URP for the Wichita Mountains and the emission reduction 
measures needed to achieve it for the period covered by the SIP;
     Section 51.308(d)(1)(ii) regarding the requirement to 
demonstrate, based on the factors in Section 51.308(d)(1)(i)(A), that 
the rate of progress for the SIP to attain natural conditions by 2064 
is not reasonable and that the progress goal adopted by Oklahoma is 
reasonable;
     Section 51.308(d)(1)(iv) regarding the requirement for 
Oklahoma to consult with Texas with respect to the visibility impact of 
Texas sources at the Wichita Mountains.
    Upon revisiting the 2016 disapprovals, we are again proposing to 
disapprove these portions of the Texas and Oklahoma Regional Haze SIPs. 
As we discuss in sections V.B--V.D, we are proposing to clarify and 
supplement the basis of our proposed disapproval of certain elements of 
the SIP submissions where the Fifth Circuit motion panel's 2016 stay 
opinion appears to reflect a misunderstanding or disagreement with the 
bases of our disapprovals. The portions for which we are proposing to 
clarify and supplement the bases of our proposed disapprovals are as 
follows:
     Texas's four-factor analysis required under section 
51.308(d)(1)(i) and (ii);
     Texas's calculation of the natural visibility conditions 
at the Guadalupe Mountains and Big Bend required under section 
51.308(d)(2)(iii);
     The portion of the Texas Regional Haze SIP that is 
intended to address the requirement in section 51.308(d)(3)(i) to 
consult with other States with Class I areas where Texas emissions are 
reasonably anticipated to contribute to visibility impairment in order 
to develop coordinated emission management strategies;
     The portion of the Texas Regional Haze SIP that is 
intended to address the requirement in section 51.308(d)(3)(ii) to 
demonstrate that the state has included in its regional haze SIP all 
measures necessary to obtain its share of the emission reductions 
needed to meet the progress goal for any Class I area in another state 
where its emissions cause or contribute to visibility impairment;
     The portion of the Texas Regional Haze SIP that is 
intended to address the requirement in section 51.308(d)(3)(iii) to 
document the technical basis on which the state is relying to determine 
its apportionment of emission reduction obligations necessary for 
achieving reasonable progress at the Guadalupe Mountains, Big Bend, and 
the Wichita Mountains;
     The portion of the Oklahoma Regional Haze SIP that is 
intended to address the requirement in section 51.308(d)(1)(iv) to 
consult with those States which may reasonably be anticipated to cause 
or contribute to visibility impairment in the Wichita Mountains.
    For the remaining portions of the Texas and Oklahoma Regional Haze 
SIPs that we are again proposing to disapprove, the bases for our 
disapproval were previously discussed in the preamble of our proposed 
rule published on December 16, 2014, and the preamble of our final rule 
published on January 5, 2016. We are relying on the same bases for 
disapproval previously discussed in those proposed and final 
rulemakings and will not repeat the rationales in this notice but 
rather refer the reader to the preamble of those prior rulemakings,\55\ 
and we incorporate those rationales by reference in this action. Those 
remaining portions we are proposing to disapprove and for which we are 
incorporating our original bases for disapproval in this action are as 
follows:
---------------------------------------------------------------------------

    \55\ See 79 FR 74818 (2014 Proposed Rule) and 81 FR 296 (2016 
Final Rule).
---------------------------------------------------------------------------

     Texas's RPGs for the Guadalupe Mountains and Big Bend 
under section 51.308(d)(1); \56\
---------------------------------------------------------------------------

    \56\ 79 FR at 74833-74843 (2014 Proposed Rule) and 81 FR 298-
299, 338, 339-343 (2016 Final Rule).
---------------------------------------------------------------------------

     Texas's calculation of the emission reductions needed to 
achieve the uniform rates of progress for the Guadalupe Mountains and 
Big Bend under section 51.308(d)(1)(i)(B); \57\
---------------------------------------------------------------------------

    \57\ 79 FR at 74832-74833 (2014 Proposed Rule) and 81 FR at 299 
(2016 Final Rule).
---------------------------------------------------------------------------

     Texas's calculation of the number of deciviews by which 
baseline conditions exceed natural conditions for the best and worst 
visibility days at the Texas Class I areas under section 
51.308(d)(2)(iv) given that this calculation relies on the 
determination of natural visibility conditions, which we are proposing 
to disapprove; \58\
---------------------------------------------------------------------------

    \58\ 79 FR at 74832 (2014 Proposed Rule) and 81 FR at 299-300 
(2016 Final Rule).
---------------------------------------------------------------------------

     The portion of the Texas Regional Haze SIP intended to 
address paragraph (C) of section 51.308(d)(3)(v), which is

[[Page 48161]]

the requirement to consider emissions limitations and schedules for 
compliance to achieve the reasonable progress goals; \59\
---------------------------------------------------------------------------

    \59\ 79 FR at 74862 (2014 Proposed Rule) and 81 FR at 301 (2016 
Final Rule).
---------------------------------------------------------------------------

     30 TAC 116.1510(d), which was incorporated into the Texas 
Regional Haze SIP and relies on the now defunct CAIR; \60\
---------------------------------------------------------------------------

    \60\ While the EPA finalized a limited disapproval of the 
regional haze SIPs submitted by Texas and thirteen other states in a 
final rule published on June 7, 2012 (77 FR 33642) because these 
states relied on requirements of CAIR to satisfy certain regional 
haze requirements, the EPA did not specifically take action in that 
final rule on Texas's BART Rules at 30 TAC section 116 that were 
incorporated in the Texas Regional Haze SIP. The EPA took final 
action on Texas's BART Rules at 30 TAC section 116 in the 2016 Final 
Rule (81 FR at 301, 312-313, 350). See also 79 FR at 74853-74854 
(2014 Proposed Rule).
---------------------------------------------------------------------------

     Oklahoma's RPGs for the Wichita Mountains under section 
51.308(d)(1) and the portions of Oklahoma's Regional Haze SIP that are 
intended to address the requirements of section 51.308(d)(1)(i)(A), 
(i)(B), and (ii) with respect to Oklahoma's establishment of its RPGs 
for the Wichita Mountains given that these portions of Oklahoma's 
Regional Haze SIP relied on and were informed by the analysis and 
results of Texas's reasonable progress analysis required under section 
51.308(d)(1).\61\
---------------------------------------------------------------------------

    \61\ Thus, Oklahoma did not have adequate information from 
Texas, nor did it request further investigation or reductions from 
those sources in Texas with the greatest potential to impact 
visibility in the Wichita Mountains to properly address these 
requirements under section 51.308(d)(1)(i) through (v) related to 
the establishment of its RPGs. See 79 FR 74818, 74864-74872 (2014 
Proposed Rule) and 81 FR 302-303, 312-313, 338, 339-343 (2016 Final 
Rule).
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B. Supplemental Bases for Our Disapproval of Texas's Four-Factor 
Analysis

    In establishing a RPG for each of its Class I areas, Texas is 
required by CAA section 169A(g)(1) and section 51.308(d)(1)(i)(A) to 
``[c]onsider 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, and include a demonstration showing how these factors were 
taken into consideration in selecting the goal.'' This requirement is 
often referred to as the reasonable progress ``four-factor analysis.'' 
In addition, section 51.308(d)(1)(ii) provides that for the period of 
the SIP, if a state establishes an RPG that provides for a slower rate 
of improvement in visibility than the rate that would be needed to 
attain natural conditions by 2064, it must demonstrate based on the 
factors in section 51.308(d)(1)(i)(A) that the rate of progress for the 
SIP to attain natural conditions by 2064 is not reasonable; and that 
the progress goal it adopted is reasonable. This requirement under 
section 51.308(d)(1)(ii) applies to Texas because its RPGs for the 20 
percent worst days establish a slower rate of progress than the URP for 
Big Bend and the Guadalupe Mountains.
    We provided a detailed discussion of the basis for our disapproval 
of Texas's four-factor analysis in the preamble of our 2014 Proposed 
Rule and provided a more abbreviated discussion of the basis for our 
disapproval in the preamble of our 2016 Final Rule.\62\ However, 
statements made by the Fifth Circuit motions panel in the 2016 stay 
opinion appear to reflect a misunderstanding of the basis of our 
disapproval of Texas's four-factor analysis. Specifically, the opinion 
indicated that the EPA disapproved the Texas SIP for failing to 
evaluate the four factors on a source-specific basis. The panel's 
opinion stated that:
---------------------------------------------------------------------------

    \62\ 79 FR 74818, 74830-74838 and 74841-74843 (Dec. 16, 2014); 
81 FR 296, 298-299, 308-311, 313-314, 318-319, 323-324, 327 (Jan. 5, 
2016).

    EPA argues that it had several grounds for disapproving the 
Texas and Oklahoma goals and suggests each alone provides a 
sufficient basis for the disapproval. Most of these `independent' 
grounds boil down to EPA's insistence that Texas should have 
conducted a source-specific requirement. Other grounds for 
disapproval were asserted in the proposed rule but were not 
finalized in the Final Rule. Compare 79 FR at 74,842-43 (proposing 
disapproval because of Texas's cost threshold, weighing of factors 
for individual sources, reliance on CAIR reductions, assumptions 
about efficiency of SO2 scrubbers, evaluation of 
potential improvements, order of magnitude estimate, and scrubber 
upgrade estimates), with 81 FR at 298-300 (finalizing disapproval 
because of lack of source-specific analysis and estimation of 
natural visibility conditions).\63\
---------------------------------------------------------------------------

    \63\ Texas, 829 F. 3d at 427-428.

    The panel's characterization is incorrect. First, as we discuss in 
the paragraphs and subsections that follow, the basis for our 
disapproval of Texas's four-factor analysis was not, and is not, tied 
to the lack of a source-specific analysis. Second, our 2016 disapproval 
included these other grounds for disapproval. Here, the panel refers to 
a subsection of the preamble of our 2016 Final Rule where we state that 
we ``present a summary of the major points of our final decision 
regarding the Texas regional haze SIP. . . and those parts of the 
Oklahoma regional haze SIP that we have not previously acted upon.'' 
\64\ Since this was intended to be a summary, this subsection of the 
2016 Final Rule did not identify and discuss in detail each of the 
``other grounds for disapproval'' in the same way our 2014 Proposed 
Rule did. However, these ``other grounds for disapproval'' were 
discussed elsewhere in our 2016 Final Rule and in our Response to 
Comments document associated with that final rule, and our disapproval 
was based on consideration of all those deficiencies.\65\ In this 
notice, we provide our evaluation of Texas's four-factor analysis and 
again identify the deficiencies with this analysis. To address concerns 
raised in the 2016 stay opinion, and where appropriate, we are 
presenting additional analysis of the SIP to more fully explain the 
deficiencies with Texas's four-factor analysis.
---------------------------------------------------------------------------

    \64\ See 81 FR at 298.
    \65\ See for instance 81 FR at 299, footnote 11, where we 
identify the lack of consideration of scrubber upgrade as part of 
the basis for our disapproval. See 81 FR at 318 where we state that 
Texas's cost threshold of $2,700/ton was unreasonable and point to 
the 2014 proposed rule that discussed the issue in detail. See also 
the Response to Comments Document (RTC) for the Texas-Oklahoma 
Reasonable Progress SIP and FIP, page 857 and 909, where we discuss 
Texas's reliance on CAIR reductions and assumptions about control 
efficiency of SO2 scrubbers. The RTC for the Texas-
Oklahoma Reasonable Progress SIP and FIP is available in the docket 
for this action at Document ID EPA-R06-OAR-2014-0754-0087.
---------------------------------------------------------------------------

    The Regional Haze Rule does not require states to conduct four-
factor analyses on a source-specific basis. CAA section 169A(b)(2) 
requires states to include in their SIPs ``emission limits, schedules 
of compliance and other measures as may be necessary to make reasonable 
progress.'' While these emission limits must apply to individual 
sources or units, CAA section 169A(g)(1) does not explicitly require 
states to consider the four factors on a source-specific basis when 
determining what amount of emission reductions (and corresponding 
visibility improvement) constitutes ``reasonable progress.'' The EPA 
has consistently interpreted the CAA to provide states with 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. While 
the CAA and the Regional Haze Rule provide states with flexibility in 
evaluating the four reasonable progress factors, states must exercise 
reasoned judgment when choosing which sources, groups of sources, or 
source categories to analyze. Consistent with the state's obligation to 
exercise reasoned judgment in its analysis, EPA's role in reviewing a 
SIP is not limited to accepting at face value a state's analysis in its 
own SIP submission and its

[[Page 48162]]

determination that it has fully satisfied the requirements of the CAA.
    Rather, Congress tasked EPA with the responsibility of ensuring 
that a SIP submission satisfies the requirements of the CAA. Abundant 
case law reflects an understanding that the EPA must evaluate SIP 
submissions under CAA section 110(k)(2) and (3).\66\ If a SIP 
submission is deficient in whole or in part, the EPA must so find, and 
if not corrected, implement the relevant requirements through a FIP 
under CAA section 110(c). Courts have held that EPA's ability to ensure 
that a SIP submission satisfies the requirements of the CAA includes 
the ability to review a state's analysis to ensure that it is 
``reasonably moored to the Act's provisions and . . . based on reasoned 
analysis.'' \67\ Thus, EPA's oversight role is ``more than the 
ministerial task of routinely approving SIP submissions.'' \68\ If 
EPA's role were otherwise, Congress would not have expressly tasked the 
agency with both reviewing SIPs for completeness (CAA section 
110(k)(1)(B)) and reviewing the substance of SIPs (CAA section 
110(k)(2)-(4)).
---------------------------------------------------------------------------

    \66\ See e.g., Oklahoma v. EPA, 723 F.3d 1201, 1209 (10th Cir. 
2013) (upholding EPA's disapproval of ``best available retrofit 
technology'' (BART) SIP, noting BART ``does not differ from other 
parts of the CAA--states have the ability to create SIPs, but they 
are subject to EPA review''); see also Westar Energy v. EPA, 608 
Fed. App'x 1, 3 (D.C. Cir. 2015) (``EPA acted well within the bounds 
of its delegated authority when it disapproved of Kansas's proposed 
[good neighbor] SIP.'').
    \67\ North Dakota v EPA, 730 F.3d 750, 761 (8th Cir. 2013).
    \68\ North Dakota v EPA, 730 F.3d 750, 761 (8th Cir. 2013). See 
also Alaska Department of Environmental Conservation v. EPA, 540 
U.S. 461, (2004) (concluding that EPA was not limited to verifying 
that a BACT determination had been made, but rather EPA could 
examine the substance of the BACT determination).
---------------------------------------------------------------------------

    As an initial matter, Texas followed a source-specific approach in 
selecting sources for evaluation in the four-factor analysis and in 
analyzing the cost of controls for individual sources, as we discussed 
in the 2014 Proposed Rule.\69\ However, as stated earlier in this 
section, we disapproved Texas's four-factor analysis not because Texas 
did not perform its four-factor analysis on a source-specific basis, 
but because the manner in which Texas analyzed and weighed the four 
reasonable progress factors was flawed and unreasonable in a number of 
key areas. First, Texas's overall approach in the selection of a set of 
sources and controls for evaluation was unreasonable and led to 
numerous potentially cost-effective controls being dismissed or 
overlooked altogether. Second, in considering the costs of compliance, 
which is one of the statutory factors States must consider under 
section 51.308(d)(1)(i)(A), Texas made unreasonable assumptions that 
resulted in the overestimation of the cost-effectiveness of controls 
and a failure to assess costs of available controls for some sources. 
Finally, in addressing the requirement under section 51.308(d)(1)(i)(A) 
to include a demonstration showing how the statutory factors were taken 
into consideration in establishing the RPGs, Texas unreasonably weighed 
the costs of compliance and the visibility benefits of controls, which 
resulted in unreasonable conclusions. We discuss these flaws in Texas's 
four-factor analysis and its weighing of the four factors in more 
detail in the subsections that follow.
---------------------------------------------------------------------------

    \69\ 79 FR at 74834-74838.
---------------------------------------------------------------------------

1. Selection of Sources for Evaluation in Four-Factor Analysis
    The Reasonable Progress Guidance for the first planning period 
provides an overview of the process for developing RPGs, potential 
methods for identifying which source categories should be evaluated for 
controls, and suggestions for evaluating the four statutory factors 
with respect to potentially affected stationary sources.\70\ The 
process begins with the identification of key pollutants and sources 
and/or source categories that are contributing to visibility impairment 
at each Class I area.\71\ A set of sources should be reasonably 
selected for the four factor analysis based on the sources and source 
categories that have been identified to contribute to visibility 
impairment at the applicable Class I areas. The Reasonable Progress 
Guidance recommends that states ``[i]dentify the control measures and 
associated emission reductions that are expected to result from 
compliance with existing rules and other available measures for the 
sources and source categories.'' \72\ States should then determine what 
additional control measures would be reasonable based on the statutory 
factors and other relevant factors for the sources and/or sources 
categories that have been identified.\73\
---------------------------------------------------------------------------

    \70\ See generally ``Guidance for Setting Reasonable Progress 
Goals Under the Regional Haze Program,'' dated June 1, 2007 
(hereafter ``Reasonable Progress Guidance'').
    \71\ Reasonable Progress Guidance at 3-1.
    \72\ Reasonable Progress Guidance at 2-3.
    \73\ Reasonable Progress Guidance at 2-3.
---------------------------------------------------------------------------

    After identification of key pollutants and source categories, Texas 
narrowed the scope of the control analysis to point sources of 
NOX and SO2 and developed a list of sources and 
potential controls and costs associated with those controls. It used 
the control strategy analysis developed by the Central Regional Air 
Planning Association (CenRAP) as the starting point for this 
analysis.\74\ Texas also included additional sources from source types 
not included in the CenRAP dataset. This work resulted in a list of 
sources and potential controls for reducing SO2 and 
NOX, an estimate of the costs associated with each control, 
and identification of the Area of Influences (AOIs) for each Class I 
area.
---------------------------------------------------------------------------

    \74\ The Central States Air Resource Agencies (CenSARA) is a 
regional planning organization (RPO) that was created in 1995 and 
currently includes as members the states of Texas, Oklahoma, 
Louisiana, Arkansas, Missouri, Kansas, Nebraska, and Iowa, as well 
as the federally recognized tribes within the boundaries of these 
states. CenSARA created CenRAP to coordinate activities associated 
with the management of regional haze issues within the member states 
and tribes. However, CenRAP has since been abolished and CenSARA 
currently conducts regional haze and other air quality planning 
activities for the CenSARA states.
---------------------------------------------------------------------------

    However, in selecting sources for the four-factor analysis, Texas 
began by eliminating certain sources purely on the basis of cost before 
the four statutory factors and the visibility benefit of controls were 
considered and weighed. Moreover, Texas failed to evaluate potentially 
cost-effective scrubber upgrades for sources with existing scrubbers 
despite the potential for large emission reductions and visibility 
benefits. Texas's overall approach in the selection of a set of sources 
and controls for evaluation was unreasonable, which led to numerous 
potentially cost-effective controls being dismissed or overlooked 
altogether. This led to the selection of a control set that was not 
appropriately refined, targeted, or focused on those sources that have 
been identified as contributing to visibility impairment and have cost-
effective controls that could result in potentially significant 
visibility benefits at the Class I areas impacted by Texas sources.
a. Texas's Cost-Effectiveness Threshold
    Texas's approach in establishing and applying a cost-threshold was 
unreasonable. Given the multitude of sources located within the State 
with the potential to impact visibility, Texas narrowed down its list 
of potential sources for which to conduct a four-factor analysis. While 
we agree that it is appropriate for a State to narrow down the list of 
sources for which to conduct a four-factor analysis, a State's 
rationale in so doing must be reasonable. When selecting the sources to 
conduct a four-factor analysis, Texas unreasonably eliminated sources 
for which the cost of controls exceeded $2,700/ton. Texas's use of a 
$2,700/ton threshold was unreasonable for several reasons including its 
reliance on the Clean Air

[[Page 48163]]

Interstate Rule (CAIR) as a justification, its failure to consider the 
four factors or take into consideration contributions to visibility 
impairment in setting the threshold, and its failure to consider the 
range of costs found reasonable by CenRAP. We discuss these points in 
turn in the following paragraphs.
    Texas used the analysis of potential cost of controls developed by 
CenRAP as the starting point for the selection of sources to evaluate 
in the four-factor analysis. CenRAP contracted with Alpine Geophysics 
to conduct an evaluation of possible additional point-source add-on 
controls for sources in CenRAP states with a Q/d >5.\75\ Alpine 
Geophysics prepared cost estimates for potential add-on controls for 
NOX and SO2 reductions in 2005 dollars for point 
sources in CenRAP states using AirControlNET,\76\ a database tool the 
EPA released in 2006 to enable cost-benefit analyses of potential 
emissions control measures and strategies. To narrow the list of 
potential controls and sources, Texas eliminated controls with an 
estimated cost-efficiency greater than $2,700/ton from any further 
analysis and did so regardless of their potential visibility benefits. 
Texas's justification for the selection of this value was a reference 
to the fact that the cost associated with implementing CAIR was up to 
$2,700/ton.\77\ However, EPA promulgated CAIR to address an entirely 
different issue--the interstate transport of emissions from states that 
contributed to unhealthy levels of ozone and particulate matter in 
certain downwind states.\78\ The interstate transport program under CAA 
section 110(a)(2)(D)(i)(I) is an entirely separate program from 
regional haze, serving a different statutory purpose and involving the 
consideration of a different set of factors.\79\ Thus, the costs 
associated with CAIR were not developed with consideration of the four 
statutory factors used to determine reasonable progress, or visibility 
impairment in general, and therefore, shouldn't be relied upon to 
eliminate sources from evaluation for potential visibility benefits. To 
the extent a state relied on a cost threshold as part of its reasonable 
progress analysis, such a cost threshold must be justified in a manner 
consistent with the CAA's expressly stated goal of addressing sources 
of visibility impairment to Class I areas.\80\ Because Texas's SIP 
justified its selection of $2,700/ton by referencing costs associated 
with a program developed to address issues unrelated to regional haze, 
it failed to adequately justify why such a threshold is reasonable in 
the context of addressing sources of visibility impairment to Class I 
areas in Texas.
---------------------------------------------------------------------------

    \75\ Q/d is the ratio of annual emissions of a given pollutant 
over distance to a Class I area and can be used to identify those 
sources with the largest potential to impact visibility.
    \76\ Lists of NOX and SO2 controls meeting 
cost thresholds ranging from $1,500/ton to $10,000/ton developed by 
Alpine Geophysics are available in the docket for this action (See 
spreadsheets titled ``nox_cost_ton__2_'' and ``so2_cost_ton'') under 
Document ID EPA-R06-OAR-2014-0754-0013, Attachments 11 and 13.
    \77\ See Texas Regional Haze SIP at 10-7. The SIP submittal is 
available in the docket for this action under Document ID EPA-R06-
OAR-2014-0754-0002.
    \78\ See generally 70 FR 25161 (May 12, 2005).
    \79\ While CAIR, and its predecessor CSAPR, were evaluated for 
BART alternatives under 40 CFR 51.308(e)(2), they were not designed 
to address visibility impairment caused by regional haze. 
Furthermore, the evaluation of CAIR and CSAPR as a BART alternative 
did not consider costs or cost thresholds.
    \80\ See, e.g., North Dakota v. EPA, 730 F.3d 750, 766 (8th Cir. 
2013).
---------------------------------------------------------------------------

    Texas's application of the $2,700/ton cost threshold unreasonably 
eliminated sources from consideration without evaluating the statutory 
factors or taking into consideration whether requiring controls on 
those sources could result in meaningful visibility improvement in 
Class I areas. In the Texas Regional Haze SIP, the State's use of a 
$2,700/ton threshold resulted in the state unreasonably overlooking 
potentially cost-effective controls that would have had a meaningful 
visibility improvement at the affected Class I areas. Given the large 
number of Texas sources and their large geographic distribution, 
Texas's failure to consider location and emissions data in applying a 
cost threshold to eliminate controls from further analysis was 
unreasonable. This is especially true for Texas, as its two Class I 
areas (Guadalupe Mountains National Park and Big Bend National Park) 
are located in far West Texas. In applying the $2,700/ton threshold, 
Texas screened out all EGUs (the largest point sources) in West Texas 
from consideration in a four-factor analysis. These EGUs in West Texas 
also impact visibility in the Class I areas located in eastern New 
Mexico (Salt Creek Wilderness Area, Carlsbad Caverns National Park, 
White Mountain Wilderness Area, and Pecos Wilderness Area) and the 
Class I area in Oklahoma (Wichita Mountains Wilderness Area). For 
example, potential SO2 controls for the Tolk Station located 
in West Texas were estimated in the Alpine Geophysics analysis to cost 
an average of approximately $3,100/ton and result in nearly 20,000 tpy 
reduced across the two units.\81\ The Tolk facility is located 
northwest of Lubbock and is in relatively close proximity to Class I 
areas in Texas, New Mexico, and Oklahoma.\82\ The Tolk units were found 
in the Alpine Geophysics analysis to each have a high Q/d \83\ for 
SO2 at multiple Class I areas,\84\ in particular at the 
Guadalupe Mountains in Texas where the Q/d is 34.4 for Unit 171B and 
31.4 for Unit 172B.
---------------------------------------------------------------------------

    \81\ Lists of SO2 controls meeting cost thresholds 
ranging from $1,500/ton to $10,000/ton developed by Alpine 
Geophysics are available in the docket to this action (See 
spreadsheet titled ``so2_cost_ton'') under Document ID EPA-R06-OAR-
2014-0754-0013, Attachment 13.
    \82\ The Tolk facility is located approximately 546 km from Big 
Bend (Texas), approximately 320 km from the Guadalupe Mountains 
(Texas), approximately 178 km from Salt Creek (New Mexico), 
approximately 277 km from the Carlsbad Caverns (New Mexico), 
approximately 298 km from the White Mountains (New Mexico), 
approximately 309 km from the Pecos Wilderness (New Mexico), and 
approximately 354 km from the Wichita Mountains (Oklahoma).
    \83\ Texas identified sources as ``high priority'' if they had 
an emissions over distance equal to or greater than five (Q/d >= 5) 
for one or more Class I areas. See Texas Regional Haze SIP at 4-3 
and 10-7.
    \84\ Based on the Alpine Geophysics Analysis, the Q/d for 
SO2 for the Tolk units is 32 for Unit 171B and 29.1 for 
Unit 172B at the Wichita Mountains in Oklahoma; 21.1 for Unit 171B 
and 19.2 for Unit 172B at Big Bend in Texas; 34.4 for Unit 171B and 
31.4 for Unit 172B at the Guadalupe Mountains in Texas; and 14.9 for 
Unit 171B and 13.5 for Unit 172B at Caney Creek in Arkansas.
---------------------------------------------------------------------------

    Beyond prematurely eliminating EGUs in West Texas, Texas's use of 
the $2,700/ton threshold also unreasonably eliminated potentially cost-
effective SO2 controls for other sources located in close 
proximity to Arkansas and Oklahoma Class I areas with a high 
SO2 Q/d. This includes the Welsh Power Plant Unit 1,\85\ 
which was found in the Alpine Geophysics analysis to have a Q/d of 69.6 
at Caney Creek and 34.2 at Upper Buffalo in Arkansas, 29.1 at the 
Wichita Mountains in Oklahoma, and 27.1 at Hercules Glades in Missouri. 
SO2 wet scrubber controls for Welsh Unit 1 were estimated to 
cost $2,852/ton and anticipated to result in approximately 10,500 tpy 
reduced. As a result of the application of this $2,700/ton threshold, 
potentially cost-effective controls were not evaluated at these and 
other sources that may result in meaningful visibility benefits at 
Texas's own Class I areas and Class I areas in surrounding states.
---------------------------------------------------------------------------

    \85\ The Welsh facility is located approximately 161 km from 
Caney Creek and 332 km from Upper Buffalo (Arkansas) and 
approximately 400 km from Wichita Mountains (Oklahoma).
---------------------------------------------------------------------------

    Finally, we note that CenRAP conducted a sensitivity analysis which 
evaluated controls for sources with a Q/d>5 and cost-effectiveness up 
to $10,000/ton. Based on that analysis, CenRAP suggested that a range 
from $4,000 to $5,000/ton would be a reasonable threshold for controls

[[Page 48164]]

because of diminishing emission reductions as costs increase beyond 
that range.\86\ While Texas otherwise relied heavily on analyses 
performed by CenRAP, it is unclear from Texas's submission why it then 
opted not to consider CenRAP's analysis when selecting their $2,700/ton 
cost threshold, nor did Texas consider the specific impact of how their 
selected threshold may have prematurely eliminated sources with 
potential cost-effective and large visibility benefits.
---------------------------------------------------------------------------

    \86\ See ``Sensitivity Run Specifications for CenRAP 
Consultation,'' available in the docket for this action under 
Document ID EPA-R06-OAR-2014-0754-0013. See also 
``so2_cost_ton.xls'' and ``nox_cost_ton_2_.xls,'' also available in 
the docket for this action under Document ID EPA-R06-OAR-2014-0754-
0013.
---------------------------------------------------------------------------

b. Scrubber Upgrades
    The EPA's guidance for setting reasonable progress goals instructs 
that States should focus on those sources that may have the greatest 
impact on visibility at Class I areas. This is consistent with the 
national goal established by Congress of remedying any existing 
impairment of visibility in Class I areas due to manmade air pollution. 
As part of its source selection, Texas also failed to consider 
evaluating EGUs with existing SO2 scrubbers for potential 
SO2 reductions in the four-factor analysis. Such failure to 
consider these sources in the four-factor analysis was unreasonable 
given the large projected emissions as shown in Table 1.

                                              Table 1--SO2 Emissions at Texas EGUs With Existing Scrubbers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           SO2 emissions (tpy) *
                                                             CAMD/NEEDS/EIA verified      Scrubber     Scrubber   --------------------------------------
            Facility name                   Unit ID                 scrubber            online year     bypass                  2018 CenRAP
                                                                                                                       2002      projection     Change
--------------------------------------------------------------------------------------------------------------------------------------------------------
Oklaunion Power.....................  1                   Wet Scrubber................         1986            Y         3,751        7,101        3,350
Limestone...........................  LIM1                Wet Scrubber................         1985            Y        16,293       12,715       -3,578
Limestone...........................  LIM2                Wet Scrubber................         1986            Y        12,974        4,983       -7,991
W.A. Parish.........................  WAP8                Wet Scrubber................         1982            Y         3,948        4,512          564
Martin Lake.........................  1                   Wet Scrubber................         1977            Y        24,832       11,351      -13,481
Martin Lake.........................  2                   Wet Scrubber................         1978            Y        22,538       11,984      -10,554
Martin Lake.........................  3                   Wet Scrubber................         1979            Y        19,024       12,396       -6,628
Monticello..........................  3                   Wet Scrubber................         1978            Y        22,889       11,882      -11,007
San Miguel..........................  SM-1                Wet Scrubber................         1982            Y        13,167        6,550       -6,617
H.W. Pirkey Power...................  1                   Wet Scrubber................         1985            Y        19,476       19,478            2
Sandow..............................  4                   Wet Scrubber................         1981            Y        23,305        8,409      -14,896
Gibbons Creek.......................  1                   Wet Scrubber................         1983            Y        10,816        2,652       -8,164
                                                                                                                  --------------------------------------
    Total...........................                                                                                   193,013      114,013      -79,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Emissions data from Texas Regional Haze SIP, Appendix 10.4b.

    We note that the AirControlNET database does not include general 
information for the cost and effectiveness of scrubber upgrades as the 
cost and reductions from these potential upgrades are typically very 
specific to the existing equipment and site-specific conditions. The 
cost of scrubber upgrades at coal-fired power plants has been evaluated 
in many other instances in both the context of BART and reasonable 
progress for both the first and second planning periods for regional 
haze. Based on what we have seen in other regional haze actions, 
upgrading an underperforming SO2 scrubber is generally very 
cost-effective.\87\ At the time Texas conducted its analysis, many EGUs 
were equipped with older vintage scrubbers and/or had scrubber bypasses 
that divert a portion of the exhaust gas around the control equipment. 
In some cases, excess scrubbing capacity is simply not being utilized. 
Texas included many of these types of sources in the maps showing AOIs 
and ``high priority'' sources for other state's Class I areas, as well 
as in the table of sources within the Class I areas AOI, in their 
correspondence with other states (see Appendix 4.2 of the Texas 
Regional Haze SIP). However, Texas omitted these sources from their 
source selection of SO2 point sources and thus did not 
consider them as part of the four-factor analysis without providing a 
reasonable justification.
---------------------------------------------------------------------------

    \87\ See, for instance, the North Dakota Regional Haze SIP: 
scrubber upgrades for the Milton R. Young Station Unit 2 were 
evaluated under BART and were found to cost $522/ton and scrubber 
upgrades with coal drying for the Coal Creek Station Units 1 and 2 
were evaluated under BART and found to cost $555/ton at each unit. 
See the EPA's final action approving the SO2 BART 
determinations for the Coal Creek Station Units 1 and 2 and for the 
Milton R. Young Station Unit 2 at 77 FR 20894 (April 6, 2012). See 
also the Wyoming Regional Haze SIP: scrubber upgrades for Wyodak 
Unit 1 were evaluated to address the RHR requirements under 40 CFR 
51.309 and found to cost $1,167/ton. The EPA approved this portion 
of the Wyoming Regional Haze SIP at 77 FR 73926 (December 12, 2012).
---------------------------------------------------------------------------

    Furthermore, even with these existing SO2 controls, some 
of these EGUs are still among the largest SO2 emitting 
sources in the State and have large Q/ds. For example, the Martin Lake 
facility had a Q/d for Guadalupe Mountains (958 km away) greater than 
37 using the projected 2018 SO2 emissions. Emissions at 
Martin Lake unit 1 in the CenRAP emission inventory were projected to 
decrease from 24,832 tpy in 2002 to 11,351 tpy in 2018. This is because 
the 2018 projected emissions include predicted emission reductions due 
to CAIR at many of these controlled facilities, suggesting some 
increase in control efficiency, decreased bypass, and/or burning fuels 
with a lower average sulfur content is already included in the 2018 
projections. Thus, even starting with this conservatively lower figure, 
upgrading the existing scrubber to 95 percent control efficiency would 
result in an approximate emission reduction of an additional 7,000 tpy 
beyond those reductions that were projected to occur due to CAIR.\88\ 
Scrubber upgrades across all three Martin Lake units could result in 
emission reductions of approximately 21,000 tpy beyond the level of 
control assumed in the 2018 projections. The EGUs Texas omitted from 
consideration in its four-factor analysis represent approximately one-
third of the total

[[Page 48165]]

projected Texas EGU SO2 emissions in 2018.\89\ This is a 
significant fraction of Texas EGU emissions that were not analyzed for 
potential emission reductions without a reasonable justification. 
Additionally, SO2 scrubber upgrade controls are typically 
very cost-effective. This is because a scrubber can be upgraded by 
reusing as many structural components and equipment in the existing 
unit as possible, such as existing structural steel and absorber 
shells, ducts, pumps, and compressors. A scrubber can be upgraded by 
applying new scrubbing technology to improve its removal efficiency, 
decrease operating costs, and improve operations and reliability for 
much less than it would cost to replace it with a new scrubber. In some 
cases, the overall removal efficiency of an existing scrubber can be 
increased by simply decreasing or eliminating the amount of emissions 
that bypass the scrubber \90\ and/or increasing the amount of reagent 
used in the scrubber, which are relatively inexpensive ways to improve 
the removal efficiency of a scrubber compared to installing a new 
scrubber. Given the projected emissions of the sources shown in Table 
1, the size of the impact from Texas emissions, and the source 
apportionment data indicating the large impact from SO2 
emissions from EGUs, we propose to find it was unreasonable for Texas 
to not perform any analysis on these sources or at least request 
additional information from the facilities concerning potential 
scrubber upgrades.
---------------------------------------------------------------------------

    \88\ Based on EPA Clean Air Markets Division (CAMD) annual 
SO2 emissions data and U.S. Energy Information 
Administration (EIA) data on reported sulfur content and tonnages of 
the fuels burned at Martin Lake Unit 1 in 2009-2013, scrubber 
upgrades achieving SO2 removal efficiency of 95 percent 
are estimated to reduce SO2 emissions to 3,706 tpy. The 
difference between the CenRAP 2018 projected SO2 
emissions for Martin Lake Unit 1 (11,351 tpy) and the estimated 
SO2 emissions resulting from scrubber upgrades (3,706 
tpy) is 7,645 tpy. See the Excel file ``Coal vs CEM data 2009-
2013.xlsx,'' ``charts'' tab, cell ``N15'' found in our docket under 
Document ID EPA-R06-OAR-2014-0754-0007, Attachment 17.
    \89\ See Texas Regional Haze SIP, Appendix 10.4b.
    \90\ Ways in which scrubber bypass can be decreased or 
eliminated include adding fan capacity, upgrading the electrical 
distribution system, and conversion to a wet stack.
---------------------------------------------------------------------------

2. Consideration of the Four Factors
    As stated previously, in establishing a RPG for each Class I area 
located within the state, Texas is required by CAA section 169A(g)(1) 
and section 51.308(d)(1)(i)(A) to ``[c]onsider 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, and include a demonstration showing 
how these factors were taken into consideration in selecting the 
goal.'' This requirement is often referred to as the reasonable 
progress four-factor analysis. In considering the costs of compliance, 
Texas made unreasonable assumptions that resulted in the overestimation 
of the cost-effectiveness of controls and a failure to assess costs of 
available controls.
a. Texas's Assumptions of SO2 Control Efficiency of 
Scrubbers
    Pursuant to CAA section 169A(g)(1) and section 51.308(d)(1)(i)(A), 
States must consider the costs of compliance. Texas's assumptions of 
the control efficiency of controls led to an overestimation of the cost 
of scrubber retrofits. The control efficiency of new scrubbers 
evaluated by CenRAP and Texas, based on the data from AirControlNET, 
was assumed to be 90 percent. SO2 scrubber retrofits are 
capable of achieving emission reductions of at least 95 percent for dry 
scrubbers and 98 percent for wet scrubbers.\91\ Texas's assumption of 
90 percent control efficiency materially affected its analysis due to 
the large visibility impact of Texas point sources, and EGUs in 
particular. For instance, the difference in emission reductions 
assuming 90 percent control efficiency compared to 98 percent is 1,851 
tons for Unit 1 and 1,891 tons for Unit 2 at Big Brown. These 
additional reductions would have further reduced the estimated costs of 
the controls to approximately $1,400/ton and increased the visibility 
benefit anticipated due to controls. At Monticello Units 1 and 2, the 
higher control efficiency would have resulted in an additional 1,500 
tons reduced at a cost of $1,700/ton. Assuming 98 percent control 
efficiency compared to 90 percent control efficiency at all the EGUs 
Texas evaluated in the four-factor analysis would have resulted in an 
additional 9,800 tons reduced. Therefore, Texas's assumptions of the 
emission reductions due to controls and their consideration of cost led 
to an overestimation of the costs of controls.\92\
---------------------------------------------------------------------------

    \91\ See the Oklahoma Regional Haze FIP at 76 FR 81728, 81742 
(Dec. 28, 2011).
    \92\ Underestimation of emission reductions also resulted in an 
underestimation of the visibility benefits.
---------------------------------------------------------------------------

b. Texas's Cost of Compliance Analysis Assumed Future CAIR Reductions 
as a Baseline
    Texas failed to consider how reliance on the 2018 emission 
projections under CAIR impacted their source selection, estimated costs 
of controls, and estimated visibility benefits of controls. A critical 
decision point in performing the cost analysis for potential controls 
is the determination of an emission baseline. Texas and CenRAP relied 
on the IPM predictions to estimate 2018 emission levels for EGUs. Texas 
identified that the majority of the emission reductions underlying the 
predicted visibility improvements in 2018 resulting from controls 
already in effect or scheduled to become effective will result from the 
CAIR program in particular. The Integrated Planning Model (IPM) 
analysis used by CenRAP predicted that due to CAIR compliance, by 2018, 
EGUs in Texas would purchase approximately 125,000 tpy of emissions 
allowances from out of state.\93\ IPM predicted that many EGUs in Texas 
would reduce their emissions either through changes in coal, increased 
efficiency of existing controls, or installation of new controls. Texas 
also noted that there is uncertainty in the size and distribution in 
emissions in the future projections and that no EGUs made an 
enforceable commitment to any particular pollution control strategy and 
preferred to retain the flexibility offered by the CAIR program.\94\ 
The CAIR program allows interstate trading of allowances and does not 
put specific emission limits on specific sources. Texas notes that 
because emission allowances can be purchased by EGUs, visibility 
improvement may be less or more that that predicted by the CenRAP's 
modeling. Nevertheless, Texas unreasonably utilized this future 
projection of 2018 emissions as the starting point for its estimation 
of emission reductions and the associated costs of additional controls 
in its four-factor analysis.\95\ Although we acknowledge that CAIR is 
now defunct and has been replaced by CSAPR, Texas presumed that those 
results would be comparable under any program to replace CAIR.
---------------------------------------------------------------------------

    \93\ CenRAP used the IPM (Version 2.19) that the EPA employed to 
predict the emissions reductions expected from CAIR in 2018 and 
Texas used the CenRAP analysis as their starting point in the four-
factor analysis. The IPM model predicts the effect of emission 
trading programs considering economics, logistics, and the specific 
regulatory environment for each EGU. The EPA released the results 
and documentation for the IPM Version 2.19 in 2005.
    \94\ See Texas Regional Haze SIP at section 10.5.
    \95\ See Texas Regional Haze SIP at 10-7, 10-8, and 10-9. While 
Texas relied on CAIR to satisfy the BART requirements for EGUs, BART 
is only one component of a long-term strategy to make reasonable 
progress for the first regional haze planing period. A state should 
look beyond BART for additional reductions when assessing reasonable 
progress.
---------------------------------------------------------------------------

    The 2018 emission projections under CAIR that Texas relied on for 
source selection assumed that sources such as W. A. Parish Units WAP5, 
WAP6, and WAP7 and Welsh Units 2 and 3 would install SO2 
controls to significantly reduce their annual SO2 emissions 
by 2018. However, it was unreasonable for Texas to rely on these 
projected CAIR reductions for the baseline in their analysis because 
there were no enforceable requirements to accompany these 
SO2 reductions. In assuming the

[[Page 48166]]

2018 emission projections under CAIR as the baseline in their analysis, 
Texas assumed a starting point where scrubbers were already installed 
and the only potential control measure considered for these units was 
to ``repower'' at an extremely high cost that far exceeded the $2,700/
ton threshold Texas applied, leading Texas to omit the W. A. Parish and 
Welsh units from their selection of sources to evaluate in the four-
factor analysis. However, similar to Big Brown and Monticello, 
scrubbers were likely cost-effective for these units and should have 
been considered for the units at Parish and Welsh. As shown in Table 2, 
the emission baseline Texas used assumed that SO2 emission 
reductions under CAIR would be 45,447 tpy across the three W. A. Parish 
units (approximately 80 percent reduction) and 21,129 tpy across the 
two Welsh units (approximately 90 percent reduction). It was 
unreasonable for Texas to omit consideration of scrubbers for Welsh and 
Parish units simply because the 2018 emission projections used as their 
baseline assumed scrubbers would already be in place in 2018 due to 
CAIR. The use of this baseline resulted in large sources being left out 
of the control set Texas evaluated in their four-factor analysis even 
though the emission reductions were not enforceable and were based on 
SO2 controls that have never been installed. In its SIP, 
Texas even acknowledged the uncertainties in its 2018 emissions 
projections by its in depth review of an updated emission projection, 
available at the time Texas was developing its SIP revision, that did 
not predict scrubber upgrades or large emission reductions at the 
Parish and Welsh Units.\96\ This highlights the uncertainty of 
projections for specific units and the sensitivity of emission 
projections to inputs in the projections, for instance, higher natural 
gas prices. Texas should have recognized the flexibility in the CAIR 
trading program and the resulting uncertainty in the projected 
emissions and projected controls. In other words, it was unreasonable 
for Texas to rely on unenforceable projected controls, and not to have 
recognized that implementation of reasonable controls under the 
Regional Haze Rule would likely not be in addition to anticipated 
reductions due to CAIR predicted by IPM but would replace or complement 
any controls predicted by IPM.
---------------------------------------------------------------------------

    \96\ The 2018 emission projections Texas used as its baseline 
were based on the Integrated Planning Model (IPM) Version 2.19; 
however, there was also an updated version of IPM available for 
review at the time Texas was developing its SIP (Version 3.0). Texas 
provided an in-depth comparison of the two IPM runs in Appendix 7-2 
of their SIP submittal. While the IPM 3.0 results estimated very 
similar overall SO2 emissions, IPM 3.0 estimated larger 
reductions at Big Brown and Monticello and did not predict scrubber 
installations or large emission reductions at the Parish and Welsh 
units. See Texas Regional Haze SIP, at pg. 10-9 and Appendix 7-2, at 
pg. 8.
    \97\ We note that the difference in projected emissions for W.A. 
Parish facility between IPM Versions 2.19 and 3.0 is 29,407 tons, 
and the difference in projected emissions for the Welsh facility is 
21,354 tons. See Texas Regional Haze SIP, Appendix 7-2, at pg.8.

                  Table 2--2002 SO2 Emissions vs. 2018 Projected SO2 Emissions Under CAIR \97\
----------------------------------------------------------------------------------------------------------------
                                                                                 2018 SO2
                                                               2002 SO2         emissions        Projected SO2
          Facility name                    Unit ID             emissions    projections under      emissions
                                                                (tpy) *        CAIR (Texas      reductions under
                                                                            baseline) (tpy) *      CAIR (tpy)
----------------------------------------------------------------------------------------------------------------
W.A. Parish......................  WAP5                             20,523              3,733             16,790
W.A. Parish......................  WAP6                             17,863              3,809             14,054
W.A. Parish......................  WAP7                             17,900              3,297             14,603
Welsh............................  2                                11,995              1,223             10,772
Welsh............................  3                                11,584              1,227             10,357
----------------------------------------------------------------------------------------------------------------
* Emissions data from Texas Regional Haze SIP, Appendix 10.4b.

    Texas's use of 2018 projections also impacted the potential 
emission reductions and cost of available controls for EGUs. For 
example, Big Brown Unit 1's SO2 emissions in 2002 were 
43,413 tpy. The IPM predictions that were incorporated into the 2018 
emission level assume that a greater than \1/3\ reduction in these 
emissions will occur in response to CAIR by switching to a coal with a 
lower sulfur content, resulting in a 2018 SO2 emission level 
of 23,142 tpy. Texas's cost-effectiveness calculation for post-
combustion controls on Big Brown Unit 1 was based on reducing that 
projected 2018 SO2 emission level of 23,142 tpy by 90 
percent, resulting in a reduction of 20,828 tpy. This results in a cost 
of $32,766,310/yr, or a cost-effectiveness calculation of $1,573/ton. 
However, the installation of a scrubber would allow Big Brown 
flexibility in fuel choice thus allowing the unit to continue to burn 
the higher average sulfur fuel it currently burns, instead of moving to 
the low sulfur coal predicted by IPM. There was no enforceable 
commitment for these emission reductions at Big Brown with the company 
preferring the flexibility afforded under CAIR and thus it was 
unreasonable for Texas to rely on these projected reductions as a 
starting point for evaluating controls for this and other EGUs without 
consideration of how the uncertainty in 2018 IPM projections may impact 
their analysis.
    Big Brown Unit 1 SO2 emissions in 2006 were 49,777 
tons.\98\ The issue of scrubber efficiency aside, a reduction of 90 
percent from these actual emission levels would result in an 
SO2 reduction of approximately 44,800 tpy. While the 
numerator ($) in the cost-effectiveness metric of $/ton will increase 
slightly beyond what was estimated by Alpine Geophysics due to an 
increased sulfur loading to the scrubber, the denominator (tons) would 
increase by more than 100 percent, thus improving (lowering) the 
overall cost-effectiveness of controlling Big Brown Unit 1 
significantly. Estimates for scrubbers at Monticello are similarly 
impacted by the cost methodology used by Texas in estimating cost-
effectiveness on a cost-per-ton basis. Similarly, the visibility 
benefits of controls estimated by Texas were based only on the 
estimated additional emission reductions beyond what was already 
estimated to occur under CAIR in 2018. Accounting for the full 
reductions that would result from installation of the scrubbers based 
on historical emissions at the time would result in larger emission 
reductions and therefore, larger estimated visibility benefits from 
controls.
---------------------------------------------------------------------------

    \98\ 2006 was the most recent year for which complete annual 
emissions data was available prior to Texas issuing the draft 
Regional Haze SIP for public comment.

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

[[Page 48167]]

    For these reasons, it was unreasonable for Texas to rely on the 
2018 projections without consideration of uncertainty and how these 
assumptions may impact their analysis. Texas should have recognized 
that implementation of reasonable controls under the Regional Haze Rule 
would likely not be in addition to anticipated reductions due to CAIR 
predicted by IPM but would replace or complement any controls predicted 
by IPM.
3. Weighing of the Four Statutory Factors and Visibility Benefits
    After consideration of the four statutory factors and other 
applicable factors, States must weigh the factors and include a 
demonstration showing how these factors were taken into consideration 
in establishing the goal as required under Section 51.308(d)(1)(i)(A) 
and (d)(1)(ii). Texas unreasonably weighed the costs of compliance and 
the visibility benefits of controls, which resulted in unreasonable 
conclusions.
a. Cost of Compliance
    Texas's use of annualized aggregate costs in determining whether 
controls were necessary to make reasonable progress for the first 
planning period was unreasonable and inconsistent with the CAA. In 
looking at the costs of compliance as part of its four-factor analysis, 
Texas stated that the total annualized aggregate cost of $324,300,000 
was too high in light of the imperceptible visibility benefits of 
controls.\99\ For reasons explained in section V.B.3.c, we find that 
Texas's characterization and consideration of visibility benefits was 
both flawed and unreasonable. Focusing on costs, the figure of 
approximately $324 million reflects the annualized cost of controls on 
the entire group of sources that Texas selected for analysis under the 
four factors. As stated previously, states have flexibility in how they 
consider the four factors; however, such flexibility must be exercised 
in a reasonable manner. While determining that a total cost of $324 
million was too high, Texas provided no context or support as to why 
that figure is too high, and importantly, what range of costs would be 
reasonable. This is especially problematic when considering that Texas 
already applied a cost-effectiveness threshold of $2,700/ton to ``limit 
the proposed controls group to cost effective measures'' \100\ and thus 
eliminate sources for which they deemed controls as too costly. Thus, 
pointing to the $324 million total annual cost as too expensive 
seemingly contradicts Texas's determination that controls on these 
sources are cost-effective. Rather, all that can be determined from 
Texas's use of the aggregate annualized cost is that it represents the 
sum total of the costs of controls for 45 units that impact one or more 
Class I areas in Texas or nearby States and that Texas had previously 
determined were cost effective as they were below its $2,700/ton cost-
threshold. As such, the way Texas relied on the annual aggregate cost 
of controls was irrational and did not constitute a reasonable 
consideration of the costs of compliance as required by the CAA and the 
RHR.
---------------------------------------------------------------------------

    \99\ See Texas Regional Haze SIP, Table 10-5.
    \100\ See Texas Regional Haze SIP at 10-7.
---------------------------------------------------------------------------

b. Texas's Approach in Grouping Sources
    The way Texas grouped sources led to unreasonable results when 
weighing the factors--namely it included multiple sources that inflated 
the total cost of controls without providing a corresponding reduction 
in visibility impairment. Texas constructed a potential control set 
consisting of a mix of large and small sources, located at various 
distances from Class I areas, with a large geographical distribution. 
While on its face, this selection of controls and sources appears broad 
and comprehensive, in analyzing how Texas constructed its control set 
and mixture of sources, we find several flaws and therefore find the 
analysis unreasonable. Because of the variation in size, type, and 
location of these sources, the potential to impact visibility and 
potential visibility benefit from controls at a given Class I area can 
vary greatly between the identified sources. This potential control set 
identified by Texas included controls on sources that would likely 
result in significant visibility benefits at several Class I areas 
(such as sources with high emissions and tall stacks), but also 
included controls on many sources with much less anticipated visibility 
benefits (such as sources with lower emissions and shorter stacks, 
located at greater distances to the Class I areas). Because Texas only 
estimated the visibility benefit by grouping all the controls together, 
it was not able to appropriately assess the potential benefit of 
controlling a more refined grouping of sources with significant, and 
potentially cost-effective, visibility benefits. While we are not 
suggesting that Texas was required to weigh the four factors and 
visibility benefits on a source-specific basis, the grouping of sources 
like the Bryans Mill Plant and the Celanese Chemical Manufacturing 
Plant together with sources like Big Brown unreasonably inflated the 
total cost of controls without providing a corresponding reduction in 
visibility impairment. Thus, Texas failed to adequately justify why 
including sources with very dissimilar potential visibility benefits in 
the same group was reasonable.
    The significant visibility benefits of controls on some sources 
being grouped together with controls on other sources that provided 
little visibility benefit only served to increase the total annual cost 
figures for the entire potential control set. For example, Texas 
identified SO2 controls at the two Big Brown units to be 
approximately $1,500/ton, significantly less than its $2,700/ton 
threshold. These controls were estimated to achieve greater than 40,000 
tpy SO2 emission reductions and would result in important 
visibility benefits given that the Big Brown units have tall stacks and 
a Q/d greater than 50 at surrounding Class I areas.\101\ Big Brown and 
the other EGUs included in Texas's evaluated control set have Q/d 
values greater than 5 at all ten Class I areas evaluated in Texas's 
estimation of visibility benefits, and these emission reductions were 
included in the estimation of potential visibility benefits at all ten 
areas. In the same potential control set, Texas included SO2 
controls at other sources with estimated costs similar or more 
expensive than those at Big Brown, but with considerably lower 
SO2 emissions reductions and lower Q/d. For instance, in the 
same control set Texas identified SO2 controls at the Bryans 
Mill Plant estimated to cost approximately $1,425/ton (similar to the 
Big Brown units), but with estimated SO2 emission reductions 
of only approximately 1,330 tpy. The Bryans Mill Plant has a Q/d less 
than 10 at any given surrounding Class I areas and thus the visibility 
benefits of SO2 controls on this source are anticipated to 
be much lower than the visibility benefits of SO2 controls 
on Big Brown. In Texas's estimation of visibility benefits, emission 
reductions at Bryans Mills Plant were only included in the estimation 
of visibility benefits at Caney Creek (Q/d = 8.2). The Q/d values for 
all other Class I areas were so low (less than 5) that Texas assumed 
that no visibility benefit would result at these Class I areas from 
reductions at the Bryans Mills Plant. Texas also included in the same 
potential control set SO2 controls at the Celanese Chemical

[[Page 48168]]

Manufacturing Plant that were estimated to be approximately $2,658/ton, 
but with estimated SO2 emission reductions of only 
approximately 1,760 tpy. The Celanese Chemical Manufacturing Plant has 
a Q/d less than 9 at any given surrounding Class I area and thus the 
visibility benefits of this SO2 control are anticipated to 
be much lower than the visibility benefits of SO2 controls 
on Big Brown. In Texas's estimation of visibility benefits, emission 
reductions at Celanese were only included in the estimation of 
visibility benefits at Salt Creek (Q/d = 5.3) and Wichita Mountains (Q/
d = 8.8). The Q/d values for all other Class I areas were so low (less 
than 5) that Texas assumed that no visibility benefit would result at 
these Class I areas from reductions at the Celanese Chemical 
Manufacturing Plant. Despite this evidence in the record of identified 
cost-effective controls that result in large emission reductions and 
large potential visibility benefits at multiple Class I areas, in 
addition to source apportionment modeling identifying large impacts 
from EGU sources, and in particular EGUs in northeast Texas, the 
unreasonable manner in which the State grouped sources in weighing the 
four factors resulted in controls at sources such as Big Brown, an EGU 
in northeast Texas, being dismissed.
---------------------------------------------------------------------------

    \101\ The Big Brown units have a Q/d of 67.6 for Unit 1 and 69 
for Unit 2 at Caney Creek in Arkansas and a Q/d of 56.9 for Unit 1 
and 58.1 for Unit 2 at Wichita Mountains in Oklahoma.
---------------------------------------------------------------------------

    Additionally, the total annualized aggregate cost of $324,300,000 
includes $53,500,000 associated with the cost of NOX 
controls. However, visibility improvement due to reductions in nitrate 
extinction are much less than the sulfate reductions at each Class I 
area as shown in Table 3.

            Table 3--Texas Estimated Reduction in Extinction
------------------------------------------------------------------------
                                                     Estimated reduction
                                                     in extinction  (Mm-
                   Class I area                              1)
                                                   ---------------------
                                                     Sulfate    Nitrate
------------------------------------------------------------------------
Big Bend..........................................      0.847      0.032
Breton............................................      0.465      0.005
Caney Creek.......................................      3.232      0.054
Carlsbad Caverns..................................      1.014      0.023
Guadalupe Mountains...............................      1.014      0.023
Salt Creek........................................      1.069     -0.081
Upper Buffalo.....................................      1.583      0.016
Wheeler Peak......................................      0.121      0.000
White Mountain....................................      0.850      0.014
Wichita Mountains.................................      2.722      0.408
------------------------------------------------------------------------

    The reduction in nitrate extinction is less than 4 percent of the 
sulfate reduction at each Class I area with the exception of Wichita 
Mountains (15 percent). Despite this very small incremental reduction 
in light extinction, Texas included costs of NOX emission 
reductions, $53,500,000, in the aggregate costs for controls of which 
represents more than 16 percent of the total aggregated cost of 
controls. Thus, the inclusion of the costs associated with 
NOX controls serves to increase the total aggregate cost but 
does not result in significant visibility benefits compared to the 
benefits that result for the SO2 controls.
c. Texas's Evaluation of Potential Visibility Improvements
    In considering whether compliance costs for sources were 
reasonable, Texas weighed the total aggregated annual costs to the 
emission reductions and estimated visibility improvement those sources 
would achieve. While visibility is not an explicitly listed factor to 
consider when determining whether additional controls are reasonable, 
the purpose of the four-factor analysis is to determine what degree of 
progress toward natural visibility conditions is reasonable. Therefore, 
the EPA has interpreted the CAA and the RHR as allowing States to 
consider visibility alongside the four statutory factors when 
determining the emission reduction measures that are necessary to make 
reasonable progress. However, while it is reasonable for a State to 
consider visibility benefits, it is not free to do so in a manner that 
is unreasonable or inconsistent with the requirements of the CAA. For 
the reasons explained in the following paragraphs, we find that Texas's 
consideration of visibility improvements was unreasonable and 
inconsistent with the requirements of the CAA.
i. Texas's Use of Visibility Thresholds
    The visibility thresholds selected by Texas to dismiss otherwise 
meaningful visibility improvement provided for by the sources it 
analyzed are inconsistent with the CAA. In evaluating and dismissing 
the estimated visibility benefit from the entire control set it 
identified, Texas states that the estimated benefit is not perceptible 
(less than 1 dv) and that it is less than 0.5 dv, the screening 
threshold used under BART requirements used to determine if a facility 
contributes to visibility impairment. However, this 0.5 dv is not an 
appropriate visibility threshold to use for the reasonable progress 
analysis, given that the modeling inputs and metrics for determining 
the visibility benefits for reasonable progress differ significantly 
from modeling conducted for purposes of BART. For example, modeling 
conducted for purposes of BART focused on the maximum anticipated 
visibility impact from the source on a single day due to the short-term 
maximum actual baseline emissions from a single facility, compared to 
clean background conditions. On the other hand, the reasonable progress 
analysis presented by Texas contemplates the visibility benefit to 
degraded background conditions anticipated for an average tpy emission 
reduction (as opposed to the impact from the total short-term maximum 
emissions from the sources) averaged across the 20 percent worst days 
at the Class I area(s) (which may not be the same days that are most 
impacted by any particular source). By looking at average impacts over 
an averaged number of days, the visibility benefits projected for a 
reasonable progress analysis would be anticipated to be significantly 
lower compared to maximum day impact metrics. Thus, using a 0.5 dv 
threshold developed for evaluating the maximum impacts under BART as a 
basis for dismissing potential controls in a reasonable progress 
analysis is unreasonable. The FIP TSD associated with the 2014 Proposed 
Rule provides a detailed discussion of the different metrics and 
modeling typically used for BART and reasonable progress analyses.\102\ 
Furthermore, even in the context of BART we have stated that even 
though the installation of BART may not result in a perceptible 
improvement in visibility, the visibility benefit may still be 
significant, as explained by the Regional Haze Rule:
---------------------------------------------------------------------------

    \102\ See Texas-Oklahoma Regional Haze FIP TSD, Appendix A, 
pages A-35-A-39, A-75.

    Even though the visibility improvement from an individual source 
may not be perceptible, it should still be considered in setting 
BART because the contribution to haze may be significant relative to 
other source contributions in the Class I area. Thus, we disagree 
that the degree of improvement should be contingent upon 
perceptibility.\103\
---------------------------------------------------------------------------

    \103\ 70 FR 39104, 39130 (July 6, 2005).

    As we stated in our final rule partially approving and partially 
disapproving a portion of the Oklahoma Regional Haze SIP and 
---------------------------------------------------------------------------
promulgating an SO2 BART FIP for Oklahoma sources:

    Given that sources are subject to BART based on a contribution 
threshold of no greater than 0.5 deciviews, it would be inconsistent 
to automatically rule out additional controls where the improvement 
in visibility may be less than 1.0 deciview or even 0.5 deciviews. A 
perceptible visibility improvement is not a requirement of the BART 
determination because visibility improvements that are not 
perceptible may still be determined to be significant.\104\
---------------------------------------------------------------------------

    \104\ 76 FR 81728, 81739 (Dec. 28, 2011).

    Thus, Texas's use of both perceptibility and the 0.5 dv threshold 
developed for use in evaluating BART, as a basis for dismissing 
potential

[[Page 48169]]

controls in a reasonable progress analysis is unreasonable.
ii. Visibility Benefits of Texas's Estimated Control Set
    Texas's conclusions regarding the visibility benefits of their 
control set at Big Bend and Guadalupe Mountains, and its determination 
that those benefits were not significant enough to justify the cost of 
controls, were unreasonable.
    Texas estimated that their control set would result in 0.16 dv 
visibility improvement at Big Bend. In estimating these deciview 
improvements, Texas estimated that the evaluated control set would 
result in a reduction in sulfate and nitrate extinction of 0.85 Mm-1 
and 0.03 Mm-1, respectively.\105\ Texas only evaluated potential 
controls to reduce NOX and SO2 emissions from 
point sources in their four-factor analysis and Texas determined that 
point sources make up over 90 percent of the projected 2018 statewide 
SO2 emissions. Given the large reduction in extinction of 
sulfate compared to nitrate, we focus our analysis on the projected 
visibility benefits of SO2 controls. All U.S. point sources 
combined were projected by CenRAP to contribute 7.19 Mm-1 in sulfate 
extinction at Big Bend. Of this 7.19 Mm-1 in extinction, CenRAP 
projected that Texas point sources alone would be responsible for 3.24 
Mm-1, or 45 percent of the U.S. point source sulfate extinction in 
2018. The next largest contribution from a State to sulfate extinction 
at Big Bend is 1.10 Mm-1 from all Louisiana point sources. Thus, the 
estimated visibility benefits for the Texas control set represent a 26 
percent reduction in visibility impairment from sulfate due to all 
Texas point sources, and a 12 percent reduction in sulfate due to all 
U.S. point sources. This is a significant reduction in visibility 
impairment and represents significant progress towards the national 
goal of eliminating manmade visibility impairment. As we discuss 
elsewhere, these potential visibility benefits of controls are impacted 
by the emission baseline assumption, control efficiency assumptions, 
and other factors that lead to an underestimation in the visibility 
benefits due to the applied controls.
---------------------------------------------------------------------------

    \105\ Texas RH SIP Appendix 10-4b, see ``Means'' tab.
---------------------------------------------------------------------------

    For Guadalupe Mountains, Texas estimated that the evaluated control 
set would result in 0.22 dv visibility improvement by securing a 
reduction in sulfate and nitrate extinction of 1.01 Mm-1 and 0.02 Mm-1, 
respectively. All U.S. point sources combined were projected by CenRAP 
to contribute 6.78 Mm-1 in sulfate extinction at Guadalupe Mountains. 
Of this 6.78 Mm-1 in extinction, CenRAP projected that Texas point 
sources alone would be responsible for 3.08 Mm-1, or 45 percent of the 
U.S. point source sulfate extinction in 2018. The next largest 
contribution from a State to sulfate extinction at GUMO is 0.47 Mm-1 
from all Louisiana point sources. The estimated visibility benefits for 
the Texas control set represent a 33 percent reduction in visibility 
impairment from sulfate due to all Texas point sources, and a 15 
percent reduction in sulfate due to all U.S. point sources.
    Evaluating potential visibility benefits in Class I areas in nearby 
States, Texas estimated that the evaluated control set would result in 
0.36 dv visibility improvement at Wichita Mountains in Oklahoma. Texas 
estimated that the evaluated control set would result in a reduction in 
sulfate and nitrate extinction of 2.72 Mm-1 and 0.41 Mm-1, respectively 
at Wichita Mountains. All U.S. point sources combined were projected by 
CenRAP to contribute 21.74 Mm-1 in sulfate extinction, including 7.83 
Mm-1 from Texas point sources, or 36 percent of the U.S. point source 
sulfate extinction in 2018. The next largest contribution from a State 
to sulfate extinction at WIMO is 2.16 Mm-1 from all Louisiana point 
sources. The estimated visibility benefits for the Texas control set 
represent a 35 percent reduction in visibility impairment from sulfate 
due to all Texas point sources, and a 12.5 percent reduction in sulfate 
due to all U.S. point sources. Similarly, the estimated visibility 
benefits for the Texas control set represent a 19 percent reduction in 
visibility impairment from nitrate due to all Texas point sources, and 
a 7 percent reduction in nitrate due to all U.S. point sources.
    Texas failed to provide a reasonable justification for why it did 
not require the control measures other than to point to the aggregate 
annual cost of controls and state that the visibility benefit would not 
be perceptible. However, as discussed in the previous section, Texas's 
consideration of the costs was also flawed. Based on the large 
percentage of contribution from Texas point sources and the amount of 
visibility impairment that would be addressed under Texas's proposed 
control strategy, Texas failed to adequately demonstrate that it is not 
reasonable to impose control measures on those sources.
iii. Texas's Use of Degraded Background Conditions
    Texas estimated the visibility improvement of potential controls by 
making comparisons to degraded background conditions instead of to 
natural background conditions. However, this approach is not 
reasonable, and the EPA has previously disapproved a regional haze SIP 
submission for utilizing the same flawed approach. For example, North 
Dakota's SIP used degraded, rather than natural background results in 
what we determined to be a flawed analysis because it greatly 
underestimates the visibility benefits of potential control options. As 
we explained in the North Dakota SIP disapproval, this is true because 
of the nonlinear nature of visibility impairment. In other words, as a 
Class I area becomes more polluted, a source's contribution to changes 
in impairment becomes geometrically less.\106\ In challenges to the SIP 
disapproval, the 8th Circuit upheld EPA's decision to disapprove the 
SIP because the SIP made comparisons to degraded background conditions 
to assess visibility benefits. Specifically, the Court noted that ``the 
goal of Sec.  169A is to attain natural visibility conditions in 
mandatory Class I Federal areas, see 42 U.S.C. 7491(a)(1), and EPA has 
demonstrated that the visibility model used by the State would serve 
instead to maintain current degraded conditions.'' \107\ Because the 
analysis Texas relied upon to evaluate visibility improvement uses 
degraded background conditions, we propose to find Texas's 
consideration and use of visibility improvement unreasonable and 
inconsistent with the requirements of the CAA.
---------------------------------------------------------------------------

    \106\ 77 FR 20894, 20912 (quoting 70 FR 39124).
    \107\ North Dakota v. EPA, 730 F.3d 750, 765-66 (8th Cir. 2013).
---------------------------------------------------------------------------

d. Texas's ``Order of Magnitude Estimate'' for Visibility Improvement
    Texas produced an ``order of magnitude estimate'' of the visibility 
improvements resulting from the level of aggregate emission reductions 
that would result from its point source control strategy using 
Particulate Matter Source Apportionment Technology (PSAT) results and 
effectiveness ratios.\108\ Texas did not model the potential emission 
reductions to estimate visibility benefits, but rather estimated the 
benefits based on the results on the 2018 basecase CenRAP modeling and 
a sensitivity run developed by CenRAP that included a large set of 
emission reductions on sources throughout the CenRAP

[[Page 48170]]

states.\109\ This methodology assumes that all emission reductions 
within a PSAT region and source category (EGU or non-EGU) have the same 
effectiveness in reducing visibility impairment.\110\ For example, 
emission reductions at non-EGU sources in the West Texas PSAT region 
would be estimated to have the same effect on visibility, regardless of 
location, like the Big Spring facility (330 km to Guadalupe Mountains) 
and the Borger facility (524 km to Guadalupe Mountains). The estimated 
effectiveness factor applied equally to all emission reductions at EGUs 
located in the East Texas source region, including Sommers Deely Spruce 
(440 km from Big Bend and 680 km from Guadalupe Mountains) and 
Monticello (850 km from Big Bend and 920 km from Guadalupe Mountains). 
Given the large difference in distances between these two facilities 
and the Class I areas, it is reasonable to expect that the 
effectiveness of emission reductions could vary greatly between the 
two. We propose to find that given the variability in the distances 
between sources and Class I areas, it was unreasonable for Texas not to 
consider how its assumptions could result in underestimation of the 
visibility benefit of controlling the sources it selected for 
consideration in its four-factor analysis.
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    \108\ The Comprehensive Air Quality Model with extensions (CAMx) 
with PSAT is a tool used to provide source apportionment of 
particulate matter species from primary sources to defined receptor 
locations by geographic region and major source category.
    \109\ See Texas RH SIP Appendix 10-2 and 10-4.
    \110\ For PSAT modeling and control analysis, Texas was divided 
into 3 regions (East Texas, West Texas, and Texas Gulf Coast). See 
Figure 5-8 of Technical Support Document for CenRAP Emissions and 
Air Quality Modeling to Support Regional Haze State Implementation 
Plans (CenRAP TSD), available in the docket for this action under 
Document ID EPA-R06-OAR-2014-0754-0014.
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C. Clarification of Our Basis for Disapproval of Texas's Calculation of 
Natural Visibility Conditions

    We are proposing to disapprove Texas's calculation of natural 
visibility conditions. Section 51.308(d)(2)(iii) requires States to 
calculate the natural visibility conditions for each Class I area 
located within the State by estimating the degree of visibility 
impairment existing under natural conditions for the most impaired and 
least impaired days, based on available monitoring information and 
appropriate data analysis techniques.
    We explained the basis for our disapproval of Texas's calculation 
of the natural visibility conditions for the Guadalupe Mountains and 
Big Bend in the preamble of our 2014 Proposed Rule and in the preamble 
of our 2016 Final Rule.\111\ While not specifically addressed in the 
2016 stay opinion, statements made by the Fifth Circuit motions panel 
appear to indicate disagreement with the EPA's disapproval of Texas's 
calculation of natural visibility conditions at the Guadalupe Mountains 
and Big Bend. Specifically, the court's opinion stated that the RHR 
grants States considerable flexibility when they estimate natural 
conditions and that EPA's natural visibility guidance expressly permits 
States to use refined approaches for the calculation of natural 
visibility and to identify other approaches that are more appropriate 
for their own situations. We agree that our guidance and the RHR allow 
states to develop an alternative approach to estimate natural 
visibility conditions.\112\ The fact that States have the option of 
calculating their own natural visibility conditions instead of using 
the default natural conditions provided in the guidance is not at 
issue. However, any such alternative approach must be supported and 
documented. As we state in our guidance, States are ``free to develop 
alternative approaches that will provide natural visibility conditions 
estimates that are technically and scientifically supportable. Any 
refined approach should be based on accurate, complete, and unbiased 
information and should be developed using a high degree of scientific 
rigor.'' \113\ Texas did not provide a technically and scientifically 
supportable approach, specifically by not adequately supporting the 
assumptions used in calculating ``refined'' estimates of natural 
visibility conditions.
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    \111\ 79 FR at 74830-74832 (2014 Proposed Rule) and 81 FR at 
299-300, 325-326 (2016 Final Rule).
    \112\ Guidance for Estimating Natural Visibility Conditions 
Under the Regional Haze Rule, EPA-454/B-03-005, September 2003. See 
also 51.308(d)(2)(iii).
    \113\ Guidance for Estimating Natural Visibility Conditions 
Under the Regional Haze Rule, EPA, September 2003, at 1-11.
---------------------------------------------------------------------------

    One alternative approach available to States is to develop and 
justify the use of alternative estimates of natural concentrations of 
fine particle components. Another option available to States is to use 
the ``new IMPROVE equation'' that was adopted for use by the IMPROVE 
Steering Committee in December 2005.\114\ This refined version of the 
IMPROVE equation provided more accurate estimates (as compared to the 
``old IMPROVE equation'') of some of the factors that affect the 
calculation of light extinction. The default natural conditions in our 
guidance \115\ were updated by the Natural Haze Levels II Committee 
utilizing the new IMPROVE equation and included some refinements to the 
estimates for the PM components.116 117 These estimates are 
referred to as the ``NCII'' default natural visibility conditions.
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    \114\ The IMPROVE program is a cooperative measurement effort 
governed by a steering committee composed of representatives from 
Federal agencies (including representatives from EPA and the federal 
land managers) and regional planning organizations. The IMPROVE 
monitoring program was established in 1985 to aid the creation of 
Federal and State implementation plans for the protection of 
visibility in Class I areas. One of the objectives of IMPROVE is to 
identify chemical species and emission sources responsible for 
existing anthropogenic visibility impairment. The IMPROVE program 
has also been a key participant in visibility-related research, 
including the advancement of monitoring instrumentation, analysis 
techniques, visibility modeling, policy formulation and source 
attribution field studies.
    \115\ Guidance for Estimating Natural Visibility Conditions 
Under the Regional Haze Rule, EPA-454/B-03-005, September 2003.
    \116\ Pitchford, Marc, 2006, Natural Haze Levels II: Application 
of the New IMPROVE Algorithm to Natural Species Concentrations 
Estimates. Final Report of the Natural Haze Levels II Committee to 
the RPO Monitoring/Data Analysis Workgroup. September 2006, 
available at: https://vista.cira.colostate.edu/improve/Publications/GrayLit/029_NaturalCondII/naturalhazelevelsIIreport.ppt.
    \117\ The second version of the natural haze level II estimates 
based on the work of the Natural Haze Levels II Committee is 
available at: https://vista.cira.colostate.edu/Docs/IMPROVE/Aerosol/NaturalConditions/NaturalConditionsII_Format2_v2.xls.
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    Texas chose to derive a ``refined'' estimate of natural visibility 
conditions rather than using the default NCII values.\118\ In 
calculating natural visibility conditions, Texas used the new IMPROVE 
equation and PM concentration estimates (i.e., the NCII values) for 
most components, but assumed that 100 percent of the fine soil and 
coarse mass concentrations in the baseline period is attributed to 
natural causes and that the corresponding estimates in the NCII values 
should be replaced. Texas did so without adequately demonstrating that 
all fine soil and coarse mass measured in the baseline period can be 
attributed to 100 percent natural sources. Anthropogenic sources of 
coarse mass and fine soil in the baseline period could have included 
emissions associated with paved and unpaved roads, agricultural 
activity, and construction activities as well. We also note that the 
impact from dust at Big Bend is less certain than at the Guadalupe 
Mountains and a different assumption may be appropriate in estimating 
natural conditions there. Furthermore, Texas itself concluded that it 
cannot verify its own assumption that all fine soil and coarse mass 
measured in the baseline period can be attributed to 100 percent 
natural sources. Texas acknowledged that the information it cites to in 
the Texas Regional Haze SIP does not quantify the percentage of 
anthropogenic or natural

[[Page 48171]]

contributions to total coarse mass and fine dust, and that some portion 
must be from human activity.\119\ We are proposing to disapprove 
Texas's calculation of natural visibility conditions for the Guadalupe 
Mountains and Big Bend because those calculations are based on the 
technically indefensible assumption that there is 0 percent dust (CM 
and soil) from human activity when Texas rightly concedes that some 
impairment ``must be from some human activity.'' \120\
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    \118\ See Chapter 5 and Appendix 5-2 of the Texas Regional Haze 
SIP.
    \119\ Appendix 5-2 of the Texas Regional Haze SIP at page 4 
Texas states in its SIP that ``while some dust (CM and Soil) at both 
of Texas' Class I areas must be from some human activity, the times 
when human caused dust is likely to be more important at these sites 
are on days with less visibility impairment than on the worst dust 
impaired days.'' Texas goes on to conclude that ``for the sake of 
the most and least impaired natural visibility estimates, to treat 
100 percent of the CM and Soil concentrations measured at each of 
its Class I areas as natural.'' See id.
    \120\ See Appendix 5-2 of the Texas Regional Haze SIP at page 4.
---------------------------------------------------------------------------

D. Clarification of Our Basis for Disapproval of Consultation Between 
Texas and Oklahoma

    In finalizing the RHR, we stated that ``successful implementation 
of the regional haze program will involve long term regional 
coordination among States,'' and that ``States will need to develop 
strategies in coordination with one another, taking into account the 
effect of emissions from one jurisdiction to air quality in another.'' 
\121\ We also noted that RPGs and long-term strategies are intricately 
linked.\122\ The regulations bear this out. Section 51.308(d)(3)(i) 
requires that States (in this case Texas) consult with other States if 
its emissions are reasonably anticipated to contribute to visibility 
impairment at that State's Class I area(s), and that Texas consult with 
other States if those States' emissions are reasonably anticipated to 
contribute to visibility impairment at the Guadalupe Mountains and Big 
Bend. We commonly refer to this as the long-term strategy consultation. 
Similarly, in developing the RPGs for its Class I area(s), Section 
51.308(d)(1)(iv) requires that States (in this case Oklahoma) consult 
with those States which may reasonably be anticipated to cause or 
contribute to visibility impairment at their Class I area(s) (in this 
case Wichita Mountains). We commonly refer to this as the reasonable 
progress consultation. Section 51.308(d)(3)(ii) requires that if a 
State's emissions (in this case Texas's emissions) cause or contribute 
to impairment in another State's Class I area, it must demonstrate that 
it has included in its regional haze SIP all measures necessary to 
obtain its share of the emission reductions needed to meet the progress 
goal for that Class I area. Section 51.308(d)(3)(iii) requires that 
States (in this case Texas) document the technical basis, including 
modeling, monitoring and emissions information, on which it is relying 
to determine its apportionment of emission reduction obligations 
necessary for achieving reasonable progress in each mandatory Class I 
area it affects. This documentation is necessary so that the interstate 
consultation process can proceed on an informed basis, and so that 
downwind states can properly assess whether any additional upwind 
emission reductions are necessary to achieve reasonable progress at 
their Class I area(s).
---------------------------------------------------------------------------

    \121\ 64 FR 35714, 35728 (July 1, 1999).
    \122\ 64 FR at 35735 (July 1, 1999).
---------------------------------------------------------------------------

    We explained the basis for our disapproval of Texas's consultation 
with Oklahoma to address visibility impairment in the Wichita 
Mountains, as required under section 51.308(d)(3)(i), in the preamble 
of our 2014 Proposed Rule and in the preamble of our 2016 Final 
Rule.\123\ We also explained the basis for our disapproval of 
Oklahoma's consultation with Texas to address visibility impairment in 
the Wichita Mountains, as required under section 51.308(d)(1)(iv), in 
the preamble of our 2014 Proposed Rule and in the preamble of our 2016 
Final Rule.\124\ As to EPA's disapproval of the consultation between 
Texas and Oklahoma, the Fifth Circuit motions panel in the 2016 stay 
opinion stated that ``EPA's disapproval seems to stem in large part 
from its assertion that Texas had to conduct a source-specific analysis 
and provide Oklahoma with that source-specific analysis.'' \125\ This 
is incorrect. The basis for our disapproval of Texas's long-term 
strategy consultation with Oklahoma was not, and is not, tied to 
whether Texas conducted a source-specific analysis and provided 
Oklahoma with that source-specific analysis. Rather, we are proposing 
to disapprove Texas's long-term strategy consultation with Oklahoma 
because it relied on and was informed by a flawed four-factor analysis 
in which Texas analyzed and weighed the four reasonable progress 
factors in a manner that is unreasonable and inconsistent with the 
requirements of the CAA and the RHR. Similarly, we are proposing to 
disapprove Oklahoma's reasonable progress consultation with Texas and 
the RPG Oklahoma established for the Wichita Mountains. Oklahoma 
unreasonably relied on and was informed by Texas's flawed four-factor 
analysis that concluded no additional control measures were necessary 
even though both States acknowledged Wichita Mountains suffers from 
``significant anthropogenic impacts from Texas'' \126\ and cost-
effective controls were available. Given that impacts from Texas point 
sources were several times greater than the impact from Oklahoma's own 
point sources, Oklahoma and Texas did not adequately justify why 
additional reductions from Texas sources were not necessary to address 
impacts at the Wichita Mountains as part of the consultation process 
required under the RHR.
---------------------------------------------------------------------------

    \123\ 79 FR at 74854-74856 (2014 Proposed Rule) and 81 FR at 
300-301, 312-313 (2016 Final Rule).
    \124\ 79 FR 74818, 74864-74872 (2014 Proposed Rule) and 81 FR 
302-303, 312-313, 338, 339-343 (2016 Final Rule).
    \125\ Texas, 829 F. 3d at 428.
    \126\ See August 3, 2007 letter from ODEQ Executive Director 
Steven Thompson to TCEQ Executive Director Glenn Shankle included in 
Appendix 4-2 of Texas Regional Haze SIP.
---------------------------------------------------------------------------

    In determining its long-term strategy under section 
51.308(d)(3)(iii), we believe that Texas had an obligation to conduct 
an appropriate technical analysis and demonstrate through that 
technical analysis (required under section 51.308(d)(3)(ii)), that it 
provided its fair share of emission reductions to Oklahoma. Texas used 
its flawed four-factor analysis to determine its ``share of the 
emission reductions needed to meet the progress goal'' for the Wichita 
Mountains and to inform its decision not to control any additional 
sources, including those that impact visibility at the Wichita 
Mountains. To the extent that Texas relied on its flawed four-factor 
analysis to address the requirements of section 51.308(d)(3)(ii) and 
51.308(d)(3)(iii), it did not develop and provide the information 
necessary to determine the reasonableness of controls at those sources 
in Texas that impact visibility at the Wichita Mountains or other Class 
I areas. For the same reasons discussed in this section regarding the 
bases for our disapproval of Texas's four-factor analysis, we are 
proposing to find that Texas's demonstration failed to satisfy the 
requirements under section 51.308(d)(3)(ii) and section 
51.308(d)(3)(iii).
    CenRAP source apportionment modeling results indicated that Texas 
is a significant contributor to visibility impairment at the Wichita 
Mountains.\127\ Point sources are the most significant contributors to 
haze at the Wichita Mountains, and the largest contributing point 
sources are Texas

[[Page 48172]]

EGUs. Texas SO2 emissions were projected in 2018 to have the 
largest visibility impacts, in terms of both absolute contribution to 
extinction and percent contribution to total extinction, at the Wichita 
Mountains in Oklahoma. Table 4 summarizes the percent of visibility 
impairment at the Wichita Mountains from Oklahoma and nearby states 
projected in 2018 based on the CenRAP modeling results.\128\
---------------------------------------------------------------------------

    \127\ See Appendix E of the Technical Support Document for 
CENRAP Emissions and Air Quality Modeling to Support Regional Haze 
SIP, included as Appendix 8-1 of the Texas Regional Haze SIP.
    \128\ These model results include estimated reductions due to 
the implementation of CAIR, other on-the-book federal and State 
rules, and some assumptions for BART reductions in Oklahoma and 
other states.

                                Table 4--Percent Contribution to Total Visibility Impairment at Wichita Mountains in 2018
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Eastern  U.S.
                                            Texas  (%)     Oklahoma  (%)  Louisiana  (%)    Kansas  (%)    Arkansas  (%)   Missouri  (%)        (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Percent Total Contribution, All                     27.5            16.3             4.8             3.8             2.3             2.8             4.2
 Pollutants.............................
Percent Point Source Contribution, All              14.0             3.9             3.4             1.4             1.3             1.7             3.2
 Pollutants.............................
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Texas (all sources and pollutants) is projected to contribute 27.5 
percent of the visibility impairment at the Wichita Mountains, compared 
to 16.3 percent for Oklahoma sources, 4.8 percent from Louisiana 
sources and 4.2 percent from sources in the Eastern U.S. Point sources 
in Texas are projected to account for 14 percent of all visibility 
impairment projected in 2018 at Wichita Mountains, compared to 3.9 
percent from Oklahoma point sources, 3.4 percent from Louisiana point 
sources and 3.2 percent from point sources in the Eastern U.S.
    Oklahoma and Texas mutually acknowledged that Texas sources 
significantly impact visibility at the Wichita Mountains in Oklahoma, 
and that the impacts from point sources in Texas are several times 
greater than the impact from Oklahoma point sources.\129\ Furthermore, 
Oklahoma asserted in its consultations with Texas, and elsewhere in the 
Oklahoma Regional Haze SIP, that the Wichita Mountains would remain 
above the URP without additional reductions from Texas sources. During 
consultation calls with Texas and other states, Oklahoma specifically 
requested additional information on feasibility and cost of controls 
for those facilities identified through the CenRAP process as having 
available controls estimated to cost less than $5,000/ton and with the 
potential to result in visibility improvements in the Wichita Mountains 
due to their location and emissions.\130\ The cost-effectiveness of all 
the Texas point sources identified by Oklahoma except one was below 
$3,000/ton. Texas relied on the cost estimates developed by CenRAP and 
shared with Oklahoma with respect to feasibility and costs of potential 
controls for which Oklahoma specifically requested information. Texas 
also identified that there is uncertainty in the size and distribution 
in emissions in the future projections and that no EGUs made an 
enforceable commitment to any particular pollution control strategy and 
preferred to retain the flexibility offered by the CAIR program.\131\
---------------------------------------------------------------------------

    \129\ See e.g., March 25, 2008 letter from TCEQ Air Quality 
Division Director Susana M. Hildebrand, P.E., to ODEQ Air Quality 
Division Director Eddie Terrill included in Appendix 4-2 of Texas 
Regional Haze SIP.
    \130\ See document entitled, ODEQ Wichita Mountains consultation 
(Aug. 16, 2007), available in the docket for this action under 
Document ID EPA-R06-OAR-2014-0754-0030.
    \131\ See Texas Regional Haze SIP at section 10.5.
---------------------------------------------------------------------------

    In addition, Texas provided Oklahoma with information that other 
sources with existing controls still have a large potential to impact 
visibility and should be analyzed for control upgrades. Specifically, 
Texas provided Oklahoma a letter on March 25, 2008, which included a 
table that listed sources of ``particular interest to Wichita Mountains 
due to their emissions and their positions within the area of 
influence.'' \132\ However, Texas did not analyze the costs of controls 
or corresponding visibility benefits of several of these sources even 
though they identified them as a source of interest. Some of these 
sources include EGUs at Martin Lake and Pirkey. In the case of Martin 
Lake, the three units combined were projected to emit over 35,000 tpy 
of SO2. SO2 emissions from the Pirkey facility 
were projected to be over 19,000 tpy. Given Texas's identification of 
these sources, it was unreasonable for Texas not to provide any further 
analysis and Texas and Oklahoma did not adequately justify why 
additional reductions from these sources were not necessary to address 
impacts at the Wichita Mountains as part of the consultation process 
required under the RHR.
---------------------------------------------------------------------------

    \132\ March 25, 2008 letter from TCEQ Air Quality Division 
Director Susana M. Hildebrand, P.E., to ODEQ Air Quality Division 
Director Eddie Terrill included in Appendix 4-2 of Texas Regional 
Haze SIP.
---------------------------------------------------------------------------

    Ultimately, Texas determined that no additional controls at its 
sources were warranted during the first planning period to help achieve 
reasonable progress at the Wichita Mountains, and Oklahoma did not 
specifically request any additional reductions from Texas sources. As a 
result, Oklahoma established RPGs for the Wichita Mountains that do not 
reflect any reasonable emission reductions from Texas beyond those that 
will be achieved by compliance with other requirements of the CAA. We 
are proposing to disapprove Texas's long-term strategy consultation 
with Oklahoma required under Section 51.308(d)(3)(i) because it relied 
on and was informed by Texas's flawed four-factor analysis, as 
discussed in Section V.B. Similarly, Oklahoma's reasonable progress 
consultation with Texas required under Section 51.308(d)(1)(iv) and the 
RPG Oklahoma established for the Wichita Mountains relied on Texas's 
flawed four-factor analysis. We are proposing to disapprove those 
portions of Oklahoma's Regional Haze SIP because they relied on and 
were informed by Texas's flawed four-factor analysis, as discussed in 
Section V.B. For the same reasons, we are proposing to find that 
Texas's demonstration failed to satisfy the requirements under section 
51.308(d)(3)(ii) and section 51.308(d)(3)(iii).

VI. Amending the FIP on Remand

    We are proposing to amend the 2016 FIP by proposing to find that no 
further federal action is needed to remedy the disapprovals of portions 
of the Texas and Oklahoma Regional Haze SIPs. We are proposing to not 
make changes to our recalculation in the 2016 FIP of the natural 
visibility conditions on the 20 percent best and worst days for the 
Guadalupe Mountains and Big Bend. We are also proposing to not make

[[Page 48173]]

changes to our recalculation in the 2016 FIP of the following metrics 
that are dependent on the calculation of the natural visibility 
conditions: the number of deciviews by which baseline visibility 
conditions exceed natural visibility conditions for the Guadalupe 
Mountains and Big Bend (i.e., our calculation of visibility impairment) 
pursuant to section 51.308(d)(2)(iv)(A) and our recalculation of the 
URPs for the 20 percent worst days for these Class I areas.
    We are proposing to rescind the SO2 emission limits 
established in the 2016 FIP. Our 2016 FIP required SO2 
emission limits for 15 coal-fired EGUs at eight power plants that 
affect visibility at the Wichita Mountains Wilderness, Big Bend 
National Park, and Guadalupe Mountains National Park. We required 
emission limits consistent with scrubber upgrades and a compliance date 
three years from the effective date of the 2016 Final Rule on the 
following units: (1) Monticello 3; (2) Sandow 4; (3) Martin Lake Units 
1, 2, and 3; and (4) Limestone Units 1 and 2. We further required 
emission limits consistent with scrubber retrofits and a compliance 
date five years from the effective date of the 2016 Final Rule on the 
following units: (1) Big Brown Units 1 and 2; (2) Monticello Units 1 
and 2; (3) Coleto Creek Unit 1; and (4) Tolk Units 171B and 172B. 
Finally, we required an SO2 emission limit for the San 
Miguel unit based on the continued operation of scrubber upgrades it 
had already installed, which the facility needed to comply with within 
one year from the effective date of the 2016 Final Rule.
    On remand, we revisited whether, in light of the Fifth Circuit's 
2016 stay opinion, as well as several changes in circumstances, the FIP 
should remain or be amended. In the interim period between the 2016 
Final Rule and this proposal, several units for which we promulgated 
emission limits in the 2016 Final Rule have shut down. These units are: 
Sandow 4; \133\ Monticello Units 1, 2, and 3; \134\ and Big Brown Units 
1 and 2.\135\ These shutdowns are permanent and enforceable because the 
CAA permits for these units have been voided. These units may not 
return to operation without going through CAA new source review 
permitting and Title V operating permitting requirements. Therefore, 
the EPA is proposing to rescind the SO2 emission limits for 
these units.
---------------------------------------------------------------------------

    \133\ See letter dated February 14, 2018, from Kim Mireles of 
Luminant to the TCEQ requesting to cancel certain air permits and 
registrations for Sandow Steam Electric Station available in the 
docket for this action.
    \134\ See letter dated February 8, 2018, from Kim Mireles of 
Luminant to the TCEQ requesting to cancel certain air permits and 
registrations for Monticello available in the docket for this 
action.
    \135\ See letter dated March 27, 2018, from Kim Mireles of 
Luminant to the TCEQ requesting to cancel certain air permits and 
registrations for Big Brown available in the docket for this action.
---------------------------------------------------------------------------

    Furthermore, several units, including Martin Lake Units 1, 2, and 
3, and Coleto Creek Unit 1 may be subject to emission limits under our 
proposed BART FIP for Texas EGUs.\136\ If finalized, these emission 
limits will provide for similar emission reductions and visibility 
improvement that would have been achieved by the emission limits for 
these units in the 2016 FIP. Therefore, we propose to find that no 
further controls beyond BART should be required for Martin Lake Units 
1, 2, and 3, and Coleto Creek Unit 1, and we propose to rescind the 
SO2 emission limits for these units.
---------------------------------------------------------------------------

    \136\ See 88 FR 28918, 28977 (May 4, 2023). In addition to the 
units listed at Martin Lake and Coleto Creek, the 2023 Texas BART 
action proposed emission limits for three units at the W.A. Parish 
facility, two units at the Harrington facility, two units at the 
Fayette facility, and one unit at the Welsh facility. We anticipate 
finalizing the proposed 2023 Texas BART action before finalizing 
this proposed Reasonable Progress action.
---------------------------------------------------------------------------

    After taking into account the Texas EGUs that have permanently shut 
down in the intervening period and those that are subject to proposed 
controls under our recently proposed Texas BART FIP, the remaining 
units for which we required SO2 limits in the 2016 FIP are 
Limestone Units 1 and 2; Tolk Units 171B and 172B; and San Miguel Unit 
1. With respect to these units, the EPA is proposing to rescind the 
SO2 emission limits. As explained above, several units in 
Texas have shut down and the EPA recently proposed BART emission limits 
for 12 units in Texas. Additionally, we took a voluntary remand on the 
2016 Final Rule, in part, due to the motion panel's finding in its stay 
opinion of the petitioners' likelihood of success on the merits. As to 
the SO2 emission limits imposed by the FIP portion of the 
2016 Final Rule, the panel found that the EPA likely did not have the 
authority to impose controls that could not be installed until after 
the end of the planning period (in this case, beyond the end of the 
first planning period, or 2018). We strongly disagree with the panel's 
view that the RHR somehow constrains States or the EPA from imposing 
controls that cannot be installed until after the end of the planning 
period. Nevertheless, in response to the panel's opinion, we revised 
the Regional Haze Rule in 2017 to clarify that for the second and 
subsequent planning periods, states or the EPA can require controls 
even if they cannot be installed until after the end of the planning 
period.\137\ In addition, we previously found that San Miguel upgraded 
its SO2 scrubber system in 2010, 2011, 2012, and 2014 to 
perform at the reasonably highest level that can be expected 
(approximately 94 percent SO2 removal efficiency) based on 
the extremely high sulfur content of the coal being burned and the 
technology available.\138\ In the 2016 FIP, we finalized an 
SO2 emission limit based on the continued operation of the 
scrubber upgrades the facility had already performed and consistent 
with recent monitoring data.\139\ As a result, we did not anticipate 
that San Miguel would have to install any additional controls in order 
to comply with the SO2 emission limit we finalized.\140\ The 
scrubber upgrades at San Miguel remain in place, and we do not 
anticipate any increase in visibility impacts from the unit.
---------------------------------------------------------------------------

    \137\ See 40 CFR 51.308(f)(2)(i).
    \138\ See ``Technical Support Document for the Cost of Controls 
Calculations for the Texas Regional Haze Federal Implementation Plan 
(Cost TSD)'' dated November 2014, pages 56-61. This is the Cost TSD 
for the 2016 Texas-Oklahoma RP FIP and is available in the docket 
for this action under Document ID EPA-R06-OAR-2014-0754-0008.
    \139\ 79 FR at 74823 (footnote 26) and 81 FR at 332 (footnote 
161).
    \140\ 81 FR at 305.
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    We propose to find that for these reasons, no additional emission 
limits are necessary to make reasonable progress for the first planning 
period. The EPA will also have an opportunity to evaluate Texas's 
analyses and determinations for the Texas second planning period 
SIP,\141\ including with respect to Limestone, Tolk, and San Miguel. 
Because we are proposing to rescind the emission limits promulgated in 
the 2016 FIP for the reasons explained in the preceding paragraphs, we 
are proposing that it is not necessary to revise our four-factor 
analysis.
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    \141\ On July 20, 2021, Texas submitted its second planning 
period Regional Haze SIP to the EPA. See ``2021 Regional Haze SIP 
Revision'' at https://www.tceq.texas.gov/airquality/sip/bart/haze_sip.html.
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    While we are proposing to rescind the SO2 emission 
limits established in the 2016 FIP, we are proposing that it is not 
necessary to revise the 2018 RPGs we calculated in the 2016 FIP. 
Section 169B(e)(1) of the CAA directed EPA to promulgate regulations 
that ``include[e] criteria for measuring `reasonable progress' toward 
the national goal.'' Consequently, the regional haze regulations for 
the first planning period direct states to develop RPGs for the most 
and least impaired days to ``measure'' the progress that will be 
achieved by the control measures in the

[[Page 48174]]

state's long-term strategy ``over the period of the implementation 
plan.'' \142\ The RPGs represent the best estimate of the degree of 
visibility improvement that is anticipated to result in the Class I 
area at the end of the planning period taking into account the measures 
included in the long-term strategy over the period of the SIP for that 
planning period. For the first planning period, the RPGs allow for 
comparisons between the progress that will be achieved by the state's 
long-term strategy and the URP,\143\ and provide a benchmark for 
assessing the adequacy of a state's SIP in 5-year periodic 
reports.\144\ In the 2016 FIP, we calculated new 2018 RPGs for the 20 
percent worst days and the 20 percent best days for the Guadalupe 
Mountains, Big Bend, and the Wichita Mountains based on our technical 
analysis in that FIP.\145\ However, it is now five years past the end 
of the first planning period. Given the timing of this action, revising 
the RPGs for 2018 would not further the purpose or intent behind 
establishing the RPGs for the first planning period. Furthermore, as we 
discussed in the preceding paragraphs, in a separate proposed rule 
recently published in the Federal Register,\146\ we proposed 
SO2 emission limits for 12 Texas EGUs under the BART 
requirements, some of which are the same EGUs for which we promulgated 
SO2 emission limits in the 2016 FIP. Additionally, several 
Texas EGUs have shut down including some of the same units addressed in 
the 2016 FIP. In evaluating the Texas and Oklahoma Regional Haze SIPs 
for the second planning period,\147\ we will have an opportunity to 
evaluate these States' four-factor analyses for the second planning 
period, including the 2028 RPGs adopted by the States. For these 
reasons, we are proposing to find that it is not necessary or practical 
at this point in time for the EPA to make further changes to the 2018 
RPGs.
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    \142\ 40 CFR 51.308(d)(1).
    \143\ 40 CFR 51.308(d)(1)(ii).
    \144\ 40 CFR 51.308(g)-(h).
    \145\ 81 FR at 347, see Table 9.
    \146\ See 88 FR 28918 (May 4, 2023).
    \147\ Texas submitted its Regional Haze SIP for the second 
planning period to EPA on July 20, 2021, and Oklahoma submitted its 
Regional Haze SIP for the second planning on August 9, 2022.
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    As described in further detail below, we find that the EPA's 
proposed revision to the FIP would not result in interference with any 
applicable CAA requirements and would be consistent with CAA section 
110(l). We note that, on the face of this action, the rescission of the 
emission limits could lead to increases in emissions of SO2 
over what was anticipated in the 2016 Final Rule. The 2016 FIP imposed 
emission limits on 15 EGUs located at eight different facilities. 
However, since that action was promulgated, six of the EGUs covered by 
the 2016 FIP have permanently shut down and retired. Due to these 
shutdowns, there are no longer emissions from these six EGUs. As a 
result, the proposed rescission of these SO2 emission limits 
will have no effect, and the emissions from these sources will be lower 
than anticipated in the 2016 FIP. In addition, the EPA recently 
proposed source-specific BART limits for four of these EGUs that, if 
finalized, would impose similar limitations on SO2 
emissions.
    For the remaining five EGUs (two EGUs located at the Limestone 
facility, two EGUs located at the Tolk facility, and one EGU located at 
San Miguel facility),\148\ the proposed rescission of the emission 
limits, which were judicially stayed from taking effect, is not 
anticipated to interfere with any applicable requirements under the 
CAA. First, the geographic areas where the five EGUs are located are 
not part of a nonattainment area for any National Ambient Air Quality 
Standards (NAAQS).\149\ The Limestone facility is located in a county 
adjacent to the Freestone/Anderson SO2 nonattainment area. 
However, at the time the EPA designated this area as nonattainment, we 
used dispersion modeling to identify nearby areas that contributed to 
the violation of the NAAQS.\150\ Based on this evaluation, we found 
that emissions from the Limestone facility did not contribute to the 
violation of the SO2 NAAQS. Additionally, since that time, 
the Big Brown facility, which was the primary source causing the NAAQS 
violations in the Freestone/Anderson SO2 nonattainment area, 
has shut down, and the EPA made a Clean Data Determination in 2021 
finding that the area is currently attaining the 1-hour SO2 
NAAQS.\151\
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    \148\ The SO2 emission limit we are proposing to 
rescind for the San Miguel facility is based on SO2 
scrubber system upgrades that the facility had already installed 
prior to the promulgation of the 2016 FIP. The SO2 
emission limit we required for San Miguel was based on the emission 
rate the facility was already meeting and thus we do not expect that 
our proposed rescission of this emission limit would result in an 
increase in SO2 emissions from this facility.
    \149\ The Limestone facility is located in Limestone County, the 
Tolk facility is located in Lamb County, and the San Miguel facility 
is located in Atascosa County. None of these counties are part of a 
nonattainment area for any NAAQS.
    \150\ See Technical Support Document for the Designation 
Recommendations for the 2010 Sulfur Dioxide National Ambient Air 
Quality Standards (NAAQS)--Supplement for Four Areas in Texas Not 
Addressed in June 30, 2016, Version, Docket No EPA-HQ-OAR-2014-0464, 
at pg. 15-16 (Nov. 29, 2016), available in the docket for this 
action.
    \151\ 86 FR 26401 (May 14, 2021).
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    Second, there are no approved attainment demonstrations in other 
areas of the State or outside of the state that rely on the 
SO2 emission limits for these five EGUs to achieve 
attainment of any of the NAAQS. At this time, the areas that may be 
potentially impacted by our rescission of the SO2 emission 
limits for Limestone, Tolk, and San Miguel are all attaining the 2010 
1-hour SO2 NAAQS, 2006 PM2.5 NAAQS, and 2012 
PM2.5 NAAQS.152 153 Additionally, rescinding the 
emission limits will not alter how these sources have been operating 
and thus the EPA does not anticipate that emission levels from these 
sources will increase such that we would expect exceedances of, or 
interference with, the SO2 and PM2.5 NAAQS to 
occur in the future in the areas where these sources are located.
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    \152\ Since SO2 is a precursor pollutant for fine 
particulate matter (PM2.5), we also address whether 
withdrawal of the FIP emission limits would interfere with 
attainment of the PM2.5 NAAQS.
    \153\ As we noted in the final rule promulgating the 2010 1-hour 
SO2 NAAQS, a significant fact for ambient SO2 
concentrations is that stationary sources are the predominant 
emission sources of SO2 and the peak, maximum 
SO2 concentrations that may occur are most likely to 
occur nearer the parent stationary source. 75 FR 35520, 35557 (June 
22, 2010).
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    Finally, the proposed rescission of the FIP provisions would not 
interfere with the ``applicable requirements'' of the regional haze 
program. This section explains how the proposed FIP revision will 
comply with applicable regional haze requirements and general 
implementation plan requirements. As such, our rescission of these FIP 
provisions will not interfere with the CAA requirements for regional 
haze, including the reasonable progress and long-term strategy 
provisions of the regional haze program.

VII. Proposed Action

    We are proposing disapproval of the portions of the Texas Regional 
Haze SIP and Oklahoma Regional Haze SIP we previously disapproved in 
our 2016 Final Rule.
    With respect to the Texas Regional Haze SIP, we are proposing 
disapproval of the portions of the Texas Regional Haze SIP addressing 
the following Regional Haze Rule requirements contained in 40 CFR part 
51: \154\
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    \154\ We are also proposing disapproval of 30 TAC 116.1510(d).
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     Section 51.308(d)(1) regarding the RPGs for the Guadalupe 
Mountains and Big Bend;
     Section 51.308(d)(1)(i)(A) regarding the four-factor 
analysis;

[[Page 48175]]

     Section 51.308(d)(1)(i)(B) regarding the requirement to 
calculate the emission reduction measures needed to achieve the URP for 
the Guadalupe Mountains and Big Bend for the period covered by the SIP;
     Section 51.308(d)(1)(ii) regarding the requirement to 
demonstrate, based on the factors in Section 51.308(d)(1)(i)(A), that 
the progress goal adopted by Texas is reasonable;
     Section 51.308(d)(2)(iii) regarding the calculation of 
natural visibility conditions for the Guadalupe Mountains and Big Bend 
for the most impaired and least impaired days;
     Section 51.308(d)(2)(iv)(A) regarding the calculation of 
the number of deciviews by which baseline conditions exceed natural 
visibility conditions for the Guadalupe Mountains and Big Bend for the 
most impaired and least impaired days;
     Section 51.308(d)(3)(i) regarding Texas's long-term 
strategy consultations with Oklahoma in order to develop coordinated 
emission management strategies to address visibility impacts at the 
Wichita Mountains;
     Section 51.308(d)(3)(ii) regarding the requirement for 
Texas to secure its share of reductions necessary to achieve the RPGs 
for the Guadalupe Mountains, Big Bend, and the Wichita Mountains;
     Section 51.308(d)(3)(iii) regarding the requirement for 
Texas to document the technical basis for its long-term strategy for 
the Guadalupe Mountains, Big Bend, and the Wichita Mountains;
     Section 51.308(d)(3)(v)(C) regarding Texas's emission 
limitations and schedules for compliance to achieve the RPGs for the 
Guadalupe Mountains, Big Bend, and the Wichita Mountains.
    We are also proposing disapproval of the portions of the Oklahoma 
Regional Haze SIP addressing the following Regional Haze Rule 
requirements contained in 40 CFR part 51:
     Section 51.308(d)(1) regarding the RPGs for the Wichita 
Mountains;
     Section 51.308(d)(1)(i)(A) regarding the four-factor 
analysis;
     Section 51.308(d)(1)(i)(B) regarding the requirement to 
consider the URP for the Wichita Mountains and the emission reduction 
measures needed to achieve it for the period covered by the SIP;
     Section 51.308(d)(1)(ii) regarding the requirement to 
demonstrate, based on the factors in Section 51.308(d)(1)(i)(A), that 
the rate of progress for the SIP to attain natural conditions by 2064 
is not reasonable and that the progress goal adopted by Oklahoma is 
reasonable;
     Section 51.308(d)(1)(iv) regarding the requirement for 
Oklahoma to consult with Texas with respect to the visibility impact of 
Texas sources at the Wichita Mountains.
    We are proposing to find that no further federal action is needed 
to remedy the proposed disapprovals of these portions of the Texas and 
Oklahoma Regional Haze SIPs. We are proposing to rescind the 
SO2 emission limitations and the associated monitoring, 
reporting, and recordkeeping requirements we established in the 2016 
FIP for Texas EGUs. We are also proposing that it is not necessary to 
revise the four-factor analysis or the numeric 2018 RPGs we established 
in the 2016 FIP for the Guadalupe Mountains, Big Bend, and the Wichita 
Mountains. Finally, we are proposing to find that our amendments to the 
2016 FIP are consistent with CAA section 110(l) because they will not 
interfere with any applicable requirement concerning attainment or 
reasonable further progress (as defined in section 7501 of this title), 
or any other applicable requirements of the CAA.

VIII. Environmental Justice Considerations

    The EPA defines environmental justice (EJ) as ``the fair treatment 
and meaningful involvement of all people regardless of race, color, 
national origin, or income with respect to the development, 
implementation, and enforcement of environmental laws, regulations, and 
policies.'' \155\ The EPA further defines the term ``fair treatment'' 
to mean that ``no group of people should bear a disproportionate burden 
of environmental harms and risks, including those resulting from the 
negative environmental consequences of industrial, governmental, and 
commercial operations or programs and policies.'' \156\ Recognizing the 
importance of these considerations to local communities, the EPA 
conducted an environmental justice screening analysis around the 
location of the facilities associated with this action to identify 
potential environmental stressors on these communities and the 
potential impacts of this action. However, the EPA is providing the 
information associated with this analysis for informational purposes 
only. The information provided herein is not a basis of the proposed 
action.
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    \155\ See https://www.epa.gov/environmentaljustice/learn-about-environmental-justice.
    \156\ Id.
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    The EPA conducted the screening analyses using EJScreen, an EJ 
mapping and screening tool that provides the EPA with a nationally 
consistent dataset and approach for combining various environmental and 
demographic indicators.\157\ The EJScreen tool presents these 
indicators at a Census block group (CBG) level or a larger user-
specified ``buffer'' area that covers multiple CBGs.\158\ An individual 
CBG is a cluster of contiguous blocks within the same census tract and 
generally contains between 600 and 3,000 people. EJScreen is not a tool 
for performing in-depth risk analysis, but is instead a screening tool 
that provides an initial representation of indicators related to EJ and 
is subject to uncertainty in some underlying data (e.g., some 
environmental indicators are based on monitoring data which are not 
uniformly available; others are based on self-reported data).\159\ For 
informational purposes, we have summarized EJScreen data within larger 
``buffer'' areas covering multiple block groups and representing the 
average resident within the buffer areas surrounding the eight 
facilities for which we are proposing to rescind emission limits. 
EJScreen environmental indicators help screen for locations where 
residents may experience a higher overall pollution burden than would 
be expected for a block group with the same total population in the 
U.S. These indicators of overall pollution burden include estimates of 
ambient particulate matter (PM2.5) and ozone concentration, 
a score for traffic proximity and volume, percentage of pre-1960 
housing units (lead paint indicator), and scores for proximity to 
Superfund sites, risk management plan (RMP) sites, and hazardous waste 
facilities.\160\ EJScreen also provides information on demographic 
indicators, including percent low-income, communities of color, 
linguistic isolation, and less than high school education.
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    \157\ The EJSCREEN tool is available at https://www.epa.gov/ejscreen.
    \158\ See https://www.census.gov/programs-surveys/geography/about/glossary.html.
    \159\ In addition, EJSCREEN relies on the five-year block group 
estimates from the U.S. Census American Community Survey. The 
advantage of using five-year over single-year estimates is increased 
statistical reliability of the data (i.e., lower sampling error), 
particularly for small geographic areas and population groups. For 
more information, see https://www.census.gov/content/dam/Census/library/publications/2020/acs/acs_general_handbook_2020.pdf.
    \160\ For additional information on environmental indicators and 
proximity scores in EJSCREEN, see ``EJSCREEN Environmental Justice 
Mapping and Screening Tool: EJSCREEN Technical Documentation,'' 
Chapter 3 and Appendix C (September 2019) at https://www.epa.gov/sites/default/files/2021-04/documents/ejscreen_technical_document.pdf.
---------------------------------------------------------------------------

    The EPA prepared EJScreen reports covering buffer areas of 
approximately 6-mile radii around the 8 facilities

[[Page 48176]]

covered by the 2016 Final Rule. From those reports, two facilities, 
Tolk and Monticello, showed EJ indices greater than the 80th national 
percentiles.\161\ For Tolk, the EJ indices greater than the 80th 
national percentiles were for ozone and lead paint, which are not 
affected by this proposed action. For Monticello, the EJ indices 
greater than the 80th national percentiles were for PM2.5, 
air toxics cancer risk, air toxics respiratory hazard index, RMP 
facility proximity, and wastewater discharge. However, the Monticello 
facility permanently shut down in 2018.\162\ No currently operating 
facility for which we are proposing to rescind emission limits showed 
an EJ index greater than the 80th national percentile for 
PM2.5, diesel particulate matter, air toxics cancer risk, 
air toxics respiratory hazard index, traffic proximity, Superfund site 
proximity, RMP facility proximity, hazardous waste site proximity, 
underground storage tanks, or wastewater discharge. The full, detailed 
EJScreen reports are provided in the docket for this rulemaking.
---------------------------------------------------------------------------

    \161\ For a place at the 80th percentile nationwide, that means 
20 percent of the U.S. population has a higher value. EPA identified 
the 80th percentile filter as an initial starting point for 
interpreting EJScreen results. The use of an initial filter promotes 
consistency for EPA programs and regions when interpreting screening 
results.
    \162\ See letter dated February 8, 2018, from Kim Mireles of 
Luminant to the TCEQ requesting to cancel certain air permits and 
registrations for Monticello available in the docket for this 
action.
---------------------------------------------------------------------------

    This action proposes to again disapprove portions of the Texas and 
Oklahoma Regional Haze SIPs for the first planning period but proposes 
to make the determination that no further federal action is necessary 
to address the proposed SIP disapprovals. As a result, this action also 
proposes to rescind SO2 emission limitations for 8 
facilities in Texas. Exposure to SO2 is associated with 
significant public health effects. Short-term exposures to 
SO2 can harm the human respiratory system and make breathing 
difficult. People with asthma, particularly children, are sensitive to 
these effects of SO2.\163\ However, the 2016 Final Rule was 
stayed by the Fifth Circuit on July 15, 2016, and the emission 
limitations have not gone into effect and therefore have never been 
implemented. Therefore, we expect that this action will not change 
potential impacts to communities. There is nothing in the record that 
indicates that this proposed action, if finalized, would have 
disproportionately high or adverse human health or environmental 
effects on communities with environmental justice concerns.
---------------------------------------------------------------------------

    \163\ See https://www.epa.gov/so2-pollution/sulfur-dioxide-basics#effects.
---------------------------------------------------------------------------

IX. Impact on Areas of Indian Country

    Following the U.S. Supreme Court decision in McGirt v. Oklahoma, 
140 S. Ct. 2452 (2020), the Governor of the State of Oklahoma requested 
approval under section 10211(a) of the Safe, Accountable, Flexible, 
Efficient Transportation Equity Act of 2005: A Legacy for Users, Public 
Law 109-59, 119 Stat. 1144, 1937 (August 10, 2005) (``SAFETEA''), to 
administer in certain areas of Indian country (as defined at 18 U.S.C. 
1151) the State's environmental regulatory programs that were 
previously approved by the EPA for areas outside of Indian country. The 
State's request excluded certain areas of Indian country further 
described below. In addition, the State only sought approval to the 
extent that such approval is necessary for the State to administer a 
program in light of Oklahoma Dept. of Environmental Quality v. EPA, 740 
F.3d 185 (D.C. Cir. 2014).\164\
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    \164\ In ODEQ v. EPA, the D.C. Circuit held that under the CAA, 
a state has the authority to implement a SIP in non-reservation 
areas of Indian country in the state, where there has been no 
demonstration of tribal jurisdiction. Under the D.C. Circuit's 
decision, the CAA does not provide authority to states to implement 
SIPs in Indian reservations. ODEQ did not, however, substantively 
address the separate authority in Indian country provided 
specifically to Oklahoma under SAFETEA. That separate authority was 
not invoked until the State submitted its request under SAFETEA, and 
was not approved until EPA's decision, described in this section, on 
October 1, 2020.
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    On October 1, 2020, the EPA approved Oklahoma's SAFETEA request to 
administer all the State's EPA-approved environmental regulatory 
programs, including the Oklahoma SIP, in the requested areas of Indian 
country. As requested by Oklahoma, the EPA's approval under SAFETEA 
does not include Indian country lands, including rights-of-way running 
through the same, that: (1) qualify as Indian allotments, the Indian 
titles to which have not been extinguished, under 18 U.S.C. 1151(c); 
(2) are held in trust by the United States on behalf of an individual 
Indian or Tribe; or (3) are owned in fee by a Tribe, if the Tribe (a) 
acquired that fee title to such land, or an area that included such 
land, in accordance with a treaty with the United States to which such 
Tribe was a party, and (b) never allotted the land to a member or 
citizen of the Tribe (collectively ``excluded Indian country lands'').
    EPA's approval under SAFETEA expressly provided that to the extent 
EPA's prior approvals of Oklahoma's environmental programs excluded 
Indian country, any such exclusions are superseded for the geographic 
areas of Indian country covered by the EPA's approval of Oklahoma's 
SAFETEA request.\165\ The approval also provided that future revisions 
or amendments to Oklahoma's approved environmental regulatory programs 
would extend to the covered areas of Indian country (without any 
further need for additional requests under SAFETEA).\166\
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    \165\ The EPA's prior actions relating to Oklahoma's SIP 
frequently noted that the SIP was not approved to apply in areas of 
Indian country (consistent with the D.C. Circuit's decision in ODEQ 
v. EPA) located in the state. See, e.g., 76 FR 81728, 81756 (Dec. 
28, 2011); 81 FR 296, 348 (Jan. 5, 2016). Such prior expressed 
limitations are superseded by the EPA's approval of Oklahoma's 
SAFETEA request.
    \166\ On December 22, 2021, EPA proposed to withdraw and 
reconsider the October 1, 2020 SAFETEA approval. See https://www.epa.gov/ok/proposed-withdrawal-and-reconsideration-and-supporting-information. EPA expects to have further discussions with 
tribal governments and State of Oklahoma as part of this 
reconsideration. EPA also notes that the October 1, 2020 approval is 
the subject of a pending challenge in federal court. Pawnee Nation 
of Oklahoma v. Regan, No. 20-9635 (10th Cir.). EPA may make further 
changes to the approval of Oklahoma's program to reflect the outcome 
of the proposed withdrawal and reconsideration of the October 1, 
2020 SAFETEA approval. To the extent any change occurs in the scope 
of Oklahoma's SIP authority in Indian country before the 
finalization of this proposed rule, such a change may affect the 
scope of the EPA's final action on the proposed rule.
---------------------------------------------------------------------------

    As explained earlier in this action, the EPA is proposing to again 
address regional haze obligations for the first planning period in 
Texas and Oklahoma. More specifically, we are proposing again to 
disapprove portions of the Oklahoma Regional Haze SIP and Texas 
Regional Haze SIP submissions that relate to reasonable progress for 
the first planning period from 2008-2018. Consistent with the D.C. 
Circuit's decision in ODEQ v. EPA and with EPA's October 1, 2020, 
SAFETEA approval, if this disapproval is finalized as proposed, this 
disapproval will apply to all Indian country within Oklahoma, other 
than the excluded Indian country lands, as described earlier. Because--
per the State's request under SAFETEA--EPA's October 1, 2020, SAFETEA 
approval does not displace any SIP authority previously exercised by 
the State under the CAA as interpreted in ODEQ v. EPA, the SIP 
disapproval will also apply to any Indian allotments or dependent 
Indian communities located outside of an Indian reservation over which 
there has been no demonstration of tribal authority.

[[Page 48177]]

X. Statutory and Executive Order Reviews

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

    This action is exempt from review by the Office of Management and 
Budget (OMB) under Executive Order 12866, as amended by Executive Order 
14094, because the proposed FIP, if finalized, would constitute a rule 
of particular applicability, as it proposes to rescind source specific 
requirements for electric generating units at eight different 
facilities located only in Texas.

B. Paperwork Reduction Act

    This action does not impose any new information collection burden 
under the PRA. Because the proposed rescission of source specific 
emission limits applies to only eight different facilities, the 
Paperwork Reduction Act does not apply. See 5 CFR 1320.3(c).

C. Regulatory Flexibility Act

    I certify that this action will not have a significant impact on a 
substantial number of small entities under the RFA. This action will 
not impose any requirements on small entities. The proposed action, if 
finalized, will rescind source specific requirements for electric 
generating units s at eight different facilities, none of which are 
small entities as defined by the RFA.

D. Unfunded Mandates Reform Act

    The EPA has determined that Title II of UMRA does not apply to this 
proposed rule. In 2 U.S.C. 1502(1) all terms in Title II of UMRA have 
the meanings set forth in 2 U.S.C. 658, which further provides that the 
terms ``regulation'' and ``rule'' have the meanings set forth in 5 
U.S.C. 601(2). Under 5 U.S.C. 601(2), ``the term `rule' does not 
include a rule of particular applicability relating to . . . 
facilities.'' Because this proposed rule is a rule of particular 
applicability relating to specific EGUs located at eight named 
facilities, the EPA has determined that it is not a ``rule'' for the 
purposes of Title II of UMRA.

E. Executive Order 13132: Federalism

    This proposed action does not have federalism implications. It will 
not have substantial direct effects on the states, on the relationship 
between the national government and the states, or on the distribution 
of power and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This proposed disapproval of a portion of the Oklahoma Regional 
Haze SIP submission that relates to reasonable progress for the first 
planning period (2008-2018) will apply, if finalized as proposed, to 
certain areas in Oklahoma with a nexus to Indian country as discussed 
in the preamble, and therefore has tribal implications as specified in 
E.O. 13175 (65 FR 67249, November 9, 2000). However, this action will 
neither impose substantial direct compliance costs on federally 
recognized tribal governments, nor preempt tribal law. This action will 
not impose substantial direct compliance costs on federally recognized 
tribal governments because no actions will be required of tribal 
governments. This action will also not preempt tribal law as no 
Oklahoma tribe implements a regulatory program under the CAA, and thus 
does not have applicable or related tribal laws. The EPA will offer 
consultation with tribal officials to allow them to provide meaningful 
input on this action.

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

    EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that EPA has reason to believe may disproportionately affect children, 
per the definition of ``covered regulatory action'' in section 2-202 of 
the Executive Order. Therefore, this action is not subject to Executive 
Order 13045 because it does not concern an environmental health risk or 
safety risk. Since this action does not concern human health, EPA's 
Policy on Children's Health also does not apply.

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

    This proposed action is not subject to Executive Order 13211 (66 FR 
28355 (May 22, 2001)), because it is not a significant regulatory 
action under Executive Order 12866.

I. National Technology Transfer and Advancement Act

    This rulemaking does not involve technical standards.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, February 16, 1994) directs 
federal agencies, to the greatest extent practicable and permitted by 
law, to make environmental justice part of their mission by identifying 
and addressing, as appropriate, disproportionately high and adverse 
human health or environmental effects of their programs, policies, and 
activities on communities with environmental justice concerns.
    The EPA believes that the human health or environmental conditions 
that exist prior to this action have the potential to result in 
disproportionate and adverse human health or environmental effects on 
communities with environmental concerns. As explained further in 
section VIII, the EPA's screening analysis provides an assessment of 
indicators related to environmental justice and overall pollution 
burden around the location of the facilities associated with this 
action and demonstrates the potential for disproportionate and adverse 
effects on the areas located near at least two of the facilities 
subject to this action; however, one of these facilities permanently 
shut down in 2018. The other facility demonstrated EJ indices greater 
than the 80th national percentiles for ozone and lead paint, which are 
potential health and environmental stressors not affected by this 
proposed action.
    The EPA believes that this action, if finalized, is not likely to 
change the human health or environmental conditions that exist prior to 
this action and that have the potential to result in disproportionate 
and adverse human health or environmental effects on communities with 
environmental concerns. This action is not expected to change potential 
community impacts associated with these indexes or add disproportional 
human health or environmental burden to these communities with the 
recission of SO2 emission limits that have never gone into 
effect. The analyses and proposed requirements included in this 
proposed rulemaking are consistent with and commensurate with the 
Regional Haze Rule and how that rule functions. Additionally, the EPA 
conducted these analyses for informational purposes only, and in a 
manner consistent with both the CAA and E.O. 12898.
    The EPA intends to promote fair treatment and provide meaningful 
involvement in developing the final action through the public notice 
and comment process. This will include a

[[Page 48178]]

virtual public hearing and public comment period, as well as additional 
outreach to promote public engagement. Information related to this 
action will be available on the EPA's website as well as in the docket 
for this action.
    The information supporting this Executive Order review is contained 
in section VIII of this Preamble as well as throughout the Preamble, 
and all supporting documents have been placed in the public docket for 
this action.

K. Determinations Under CAA Section 307(d)

    This proposed action is subject to the provisions of section 
307(d). CAA section 307(d)(1)(B) provides that section 307(d) applies 
to, among other things, ``the promulgation or revision of an 
implementation plan by the Administrator under [CAA section 110(c)].'' 
42 U.S.C. 7407(d)(1)(B). If finalized, this proposed action would, 
among other things, revise a federal implementation plan pursuant to 
the authority of section 110(c). To the extent any portion of this 
proposed action is not expressly identified under section 307(d)(1)(B), 
the Administrator determines that the provisions of section 307(d) 
apply to this proposed action. See CAA section 307(d)(1)(V) (the 
provisions of section 307(d) apply to ``such other actions as the 
Administrator may determine'').

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Regional haze, Reporting and 
recordkeeping requirements, Sulfur dioxides, Visibility.

Michael S. Regan,
Administrator.

    For the reasons stated in the preamble, the EPA proposes to amend 
40 CFR part 52 as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

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

Subpart LL--Oklahoma

0
2. Section 52.1928 is amended by revising paragraph (a)(5) to read as 
follows:


Sec.  52.1928  Visibility protection.

    (a) * * *
    (5) The reasonable progress goals for the first planning period and 
the reasonable progress consultation with Texas for the Wichita 
Mountains Class I area.
* * * * *

Subpart SS--Texas

0
3. Section 52.2270 is amended by revising in paragraph (e) the ``Texas 
Regional Haze SIP'' entry under the table titled ``EPA Approved 
Nonregulatory Provisions and Quasi-Regulatory Measures in the Texas 
SIP'' to read as follows:


Sec.  52.2270   Identification of plan.

* * * * *
    (e) * * *

              EPA Approved Nonregulatory Provisions and Quasi-Regulatory Measures in the Texas SIP
----------------------------------------------------------------------------------------------------------------
                                                          State
                                     Applicable        submittal/
     Name of SIP provision          geographic or       effective     EPA approval date          Comments
                                 nonattainment area       date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Texas Regional Haze SIP........  Statewide.........       3/19/2009  1/5/2016, 81 FR     The following sections
                                                                      350.                are not approved as
                                                                                          part of the SIP: The
                                                                                          reasonable progress
                                                                                          goals, the reasonable
                                                                                          progress four-factor
                                                                                          analysis; and the
                                                                                          calculation of the
                                                                                          emission reductions
                                                                                          needed to achieve the
                                                                                          uniform rates of
                                                                                          progress for the
                                                                                          Guadalupe Mountains
                                                                                          and Big Bend; the
                                                                                          demonstration that the
                                                                                          rate of progress for
                                                                                          the implementation
                                                                                          plan to attain natural
                                                                                          conditions by 2064 is
                                                                                          not reasonable and
                                                                                          that the progress goal
                                                                                          adopted by the State
                                                                                          is reasonable;
                                                                                          calculation of natural
                                                                                          visibility conditions;
                                                                                          calculation of the
                                                                                          number of deciviews by
                                                                                          which baseline
                                                                                          conditions exceed
                                                                                          natural visibility
                                                                                          conditions; long-term
                                                                                          strategy consultations
                                                                                          with Oklahoma; Texas
                                                                                          securing its share of
                                                                                          reductions necessary
                                                                                          to achieve the
                                                                                          reasonable progress
                                                                                          goals at Big Bend, the
                                                                                          Guadalupe Mountains,
                                                                                          and the Wichita
                                                                                          Mountains; technical
                                                                                          basis for its long-
                                                                                          term strategy and
                                                                                          emission limitations
                                                                                          and schedules for
                                                                                          compliance to achieve
                                                                                          the RPGs for Big Bend,
                                                                                          the Guadalupe
                                                                                          Mountains and Wichita
                                                                                          Mountains.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

Sec.  52.2302   [Removed and Reserved]

0
4. Remove and reserve Sec.  52.2302.
0
5. Section 52.2304 is amended by revising paragraph (e) to read as 
follows:


Sec.  52.2304   Visibility protection.

* * * * *
    (e) The following portions of the Texas Regional Haze SIP submitted 
March 19, 2009 are disapproved: The reasonable progress goals, the 
reasonable progress four-factor analysis; and the calculation of the 
emission reductions needed to achieve the uniform rates of progress for 
the Guadalupe Mountains and Big Bend; the demonstration that the rate 
of progress

[[Page 48179]]

for the implementation plan to attain natural conditions by 2064 is not 
reasonable and that the progress goal adopted by the State is 
reasonable; calculation of natural visibility conditions; calculation 
of the number of deciviews by which baseline conditions exceed natural 
visibility conditions; long-term strategy consultations with Oklahoma; 
Texas securing its share of reductions necessary to achieve the 
reasonable progress goals at Big Bend, the Guadalupe Mountains, and the 
Wichita Mountains; technical basis for its long-term strategy and 
emission limitations and schedules for compliance to achieve the 
reasonable progress goals for Big Bend, the Guadalupe Mountains and 
Wichita Mountains.
* * * * *
[FR Doc. 2023-15338 Filed 7-25-23; 8:45 am]
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