`[Federal Register Volume 89, Number 244 (Thursday, December 19, 2024)]
[Proposed Rules]
[Pages 103737-103761]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-29595]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2024-0459; FRL-12287-01-R9]


Partial Approval and Partial Disapproval of Air Quality 
Implementation Plans; California; Regional Haze State Implementation 
Plan for the Second Implementation Period

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
partially approve and partially disapprove the regional haze state 
implementation plan (SIP) revision submitted by California on August 9, 
2022 (hereinafter the ``2022 California Regional Haze Plan'' or ``the 
Plan''), under the Clean Air Act (CAA) and the EPA's Regional Haze Rule 
for the program's second implementation period. California's SIP 
submission addresses the requirement that states must periodically 
revise their long-term strategies for making reasonable progress 
towards the national goal of preventing any future, and remedying any 
existing, anthropogenic impairment of visibility, including regional 
haze, in mandatory Class I Federal areas. The SIP submission also 
addresses other applicable requirements for the second implementation 
period of the regional haze program. The EPA is taking this action 
pursuant to CAA sections 110 and 169A.

DATES: Written comments must be received on or before February 3, 2025.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2024-0459 at https://www.regulations.gov. For comments submitted at 
Regulations.gov, follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or removed from 
Regulations.gov. The EPA may publish any comment received to its public 
docket. Do not submit electronically any information you consider to be 
confidential business information (CBI) or other information whose 
disclosure is restricted by statute. Multimedia submissions (audio, 
video, etc.) must be accompanied by a written comment. The written 
comment is considered the official comment and should include 
discussion of all points you wish to make. The EPA will generally not 
consider comments or comment contents located outside of the primary 
submission (i.e., on the web, cloud, or other file sharing system). For 
additional submission methods, please contact the person identified in 
the FOR FURTHER INFORMATION CONTACT section. For the full EPA public 
comment policy, information about CBI or multimedia submissions, and 
general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets. If you need assistance in a 
language other than English or if you are a person with a disability 
who needs a reasonable accommodation at no cost to you, please contact 
the person identified in the FOR FURTHER INFORMATION CONTACT section.

FOR FURTHER INFORMATION CONTACT: Laura Lawrence, Planning Section (ARD-
2-1), Planning & Analysis Branch, EPA Region IX, 75 Hawthorne Street, 
San Francisco, CA 94105, 415-972-3407, or by email at 
[email protected].

SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,'' 
and ``our'' refer to the EPA.

Table of Contents

I. What action is the EPA proposing?
II. Background and Requirements for Regional Haze Plans

[[Page 103738]]

    A. Regional Haze Background
    B. Roles of Agencies in Addressing Regional Haze
III. Requirements for Regional Haze Plans for the Second 
Implementation Period
    A. Identification of Class I Areas
    B. Calculations of Baseline, Current, and Natural Visibility 
Conditions; Progress to Date; and the Uniform Rate of Progress
    C. Long-Term Strategy for Regional Haze
    D. Reasonable Progress Goals
    E. Monitoring Strategy and Other State Implementation Plan 
Requirements
    F. Requirements for Periodic Reports Describing Progress Towards 
the Reasonable Progress Goals
    G. Requirements for State and Federal Land Manager Coordination
IV. The EPA's Evaluation of California's Regional Haze Submission 
for the Second Implementation Period
    A. Background on California's First Implementation Period SIP 
Submission
    B. California's Second Implementation Period SIP Submission
    C. Identification of Class I Areas
    D. Calculations of Baseline, Current, and Natural Visibility 
Conditions; Progress to Date; and the Uniform Rate of Progress
    E. Long-Term Strategy for Regional Haze
    F. Reasonable Progress Goals
    G. Additional Monitoring To Assess Reasonably Attributable 
Visibility Impairment
    H. Monitoring Strategy and Other Implementation Plan 
Requirements
    I. Requirements for Periodic Reports Describing Progress Towards 
the Reasonable Progress Goals
    J. Requirements for State and Federal Land Manager Coordination
V. Proposed Action
VI. Statutory and Executive Order Reviews

I. What action is the EPA proposing?

    On August 9, 2022, the California Air Resources Board (CARB) 
submitted the 2022 California Regional Haze Plan to address the 
requirements of the CAA's regional haze program pursuant to CAA 
sections 169A and 169B and 40 CFR 51.308. For the reasons described in 
this document, the EPA is proposing to approve the elements of the Plan 
related to requirements contained in 40 CFR 51.308(f)(1), 40 CFR 
51.308(f)(4)-(6), and 40 CFR 51.308(g)(1)-(5). The EPA is proposing to 
disapprove the elements of the Plan related to requirements contained 
in 40 CFR 51.308(f)(2), 40 CFR 51.308(f)(3), and 40 CFR 51.308(i)(2)-
(4).

II. Background and Requirements for Regional Haze Plans

A. Regional Haze Background

    In the 1977 CAA Amendments, Congress created a program for 
protecting visibility in the nation's mandatory Class I Federal areas, 
which include certain national parks and wilderness areas.\1\ The CAA 
establishes as a national goal the ``prevention of any future, and the 
remedying of any existing, impairment of visibility in mandatory class 
I Federal areas which impairment results from manmade air pollution.'' 
\2\ The CAA further directs the EPA to promulgate regulations to assure 
reasonable progress toward meeting this national goal.\3\ On December 
2, 1980, the EPA promulgated regulations to address visibility 
impairment in mandatory Class I Federal areas (hereinafter referred to 
as ``Class I areas'') that is ``reasonably attributable'' to a single 
source or small group of sources.\4\ These regulations, codified at 40 
CFR 51.300 through 51.307, represented the first phase of the EPA's 
efforts to address visibility impairment. In 1990, Congress added 
section 169B to the CAA to further address visibility impairment, 
specifically, impairment from regional haze.\5\ The EPA promulgated the 
Regional Haze Rule (RHR), codified at 40 CFR 51.308,\6\ on July 1, 
1999.\7\ These regional haze regulations are a central component of the 
EPA's comprehensive visibility protection program for Class I areas.
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    \1\ CAA 169A. Areas statutorily designated as mandatory Class I 
Federal areas consist of national parks exceeding 6,000 acres, 
wilderness areas and national memorial parks exceeding 5,000 acres, 
and all international parks that were in existence on August 7, 
1977. CAA 162(a). There are 156 mandatory Class I areas. The list of 
areas to which the requirements of the visibility protection program 
apply is in 40 CFR part 81, subpart D.
    \2\ CAA 169A(a)(1).
    \3\ CAA 169A(a)(4).
    \4\ 45 FR 80084 (December 2, 1980).
    \5\ CAA 169B.
    \6\ In addition to the generally applicable regional haze 
provisions at 40 CFR 51.308, the EPA also promulgated regulations 
specific to addressing regional haze visibility impairment in Class 
I areas on the Colorado Plateau at 40 CFR 51.309. The latter 
regulations are applicable only for specific jurisdictions' regional 
haze plans submitted no later than December 17, 2007, and thus are 
not relevant here.
    \7\ 64 FR 35714.
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    Regional haze is visibility impairment that is produced by a 
multitude of anthropogenic sources and activities which are located 
across a broad geographic area and that emit pollutants that impair 
visibility. Visibility impairing pollutants include fine and coarse 
particulate matter (PM) (e.g., sulfates, nitrates, organic carbon, 
elemental carbon, and soil dust) and their precursors (e.g., sulfur 
dioxide (SO2), nitrogen oxides (NOX), and, in 
some cases, volatile organic compounds (VOC) and ammonia 
(NH3)). Fine particle precursors react in the atmosphere to 
form fine particulate matter (PM2.5), which impairs 
visibility by scattering and absorbing light. Visibility impairment 
reduces the perception of clarity and color, as well as visible 
distance.\8\
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    \8\ There are several ways to measure the amount of visibility 
impairment, i.e., haze. One such measurement is the deciview, which 
is the principal metric used by the RHR. Under many circumstances, a 
change in one deciview will be perceived by the human eye to be the 
same on both clear and hazy days. The deciview is unitless. It is 
proportional to the logarithm of the atmospheric extinction of 
light, which is the perceived dimming of light due to it being 
scattered and absorbed as it passes through the atmosphere. 
Atmospheric light extinction (b\ext\) is a metric used for 
expressing visibility and is measured in inverse megameters 
(Mm-1). The EPA's August 20, 2019 Guidance on Regional 
Haze State Implementation Plans for the Second Implementation Period 
(``2019 Guidance'') offers the flexibility for the use of light 
extinction in certain cases. Light extinction can be simpler to use 
in calculations than deciviews because it is not a logarithmic 
function. See, e.g., 2019 Guidance at 16, 19, https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period. The formula for the deciview is 10 ln 
(b\ext\)/10 Mm-1). 40 CFR 51.301.
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    To address regional haze visibility impairment, the 1999 RHR 
established an iterative planning process that requires both States in 
which Class I areas are located and states ``the emissions from which 
may reasonably be anticipated to cause or contribute to any impairment 
of visibility'' in a Class I area to periodically submit SIP revisions 
to address such impairment.\9\ 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.'' \10\ The 
initial round of SIP submissions also had to address the statutory 
requirement that certain older, larger sources of visibility impairing 
pollutants install and operate the best available retrofit technology 
(BART).\11\ States' first regional haze SIPs were due by December 17, 
2007,\12\ with subsequent SIP submissions containing updated long-term 
strategies originally due July 31, 2018, and every ten years 
thereafter.\13\ The EPA established in the 1999 RHR that all States 
either have Class I areas within their borders or ``contain sources 
whose emissions are reasonably anticipated to contribute to regional 
haze in a Class I area''; therefore, all States must submit regional 
haze SIPs.\14\
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    \9\ CAA 169A(b)(2). The RHR expresses the statutory requirement 
for states to submit plans addressing out-of-state Class I areas by 
providing that states must address visibility impairment ``in each 
mandatory Class I Federal area located outside the State that may be 
affected by emissions from within the State.'' 40 CFR 51.308(d), 
(f). See also 40 CFR 51.308(b), (f) (establishing submission dates 
for iterative regional haze SIP revisions).
    \10\ CAA 169A(b)(2)(B).
    \11\ CAA 169A(b)(2)(A); 40 CFR 51.308(d), (e).
    \12\ 40 CFR 51.308(b).
    \13\ 64 FR 35768 (July 1, 1999).
    \14\ Id. at 35721. In addition to each of the fifty states, the 
EPA also concluded that the Virgin Islands and District of Columbia 
must also submit regional haze plans because they either contain a 
Class I area or contain sources whose emissions are reasonably 
anticipated to contribute regional haze in a Class I area. See 40 
CFR 51.300(b), (d)(3).

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[[Page 103739]]

    Much of the focus in the first implementation period of the 
regional haze program, which ran from 2007 through 2018, was on 
satisfying States' BART obligations. First implementation period SIPs 
were additionally required to contain long-term strategies for making 
reasonable progress toward the national visibility goal, of which BART 
is one component. The core required elements for the first 
implementation period SIPs (other than BART) are laid out in 40 CFR 
51.308(d). Those provisions required that States containing Class I 
areas establish reasonable progress goals (RPGs) that are measured in 
deciviews and reflect the anticipated visibility conditions at the end 
of the implementation period including from implementation of States' 
long-term strategies. The first planning period RPGs were required to 
provide for an improvement in visibility for the most impaired days 
over the period of the implementation plan and ensure no degradation in 
visibility for the least impaired days over the same period. In 
establishing the RPGs for any Class I area in a State, the State was 
required to consider four statutory factors: the costs of compliance, 
the time necessary for compliance, the energy and non-air quality 
environmental impacts of compliance, and the remaining useful life of 
any potentially affected sources.\15\
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    \15\ CAA 169A(g)(1); 40 CFR 51.308(d)(1).
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    States were also required to calculate baseline (using the five 
year period of 2000-2004) and natural visibility conditions (i.e., 
visibility conditions without anthropogenic visibility impairment) for 
each Class I area, and to calculate the linear rate of progress needed 
to attain natural visibility conditions, assuming a starting point of 
baseline visibility conditions in 2004 and ending with natural 
conditions in 2064. This linear interpolation is known as the uniform 
rate of progress (URP) and is used as a tracking metric to help States 
assess the amount of progress they are making towards the national 
visibility goal over time in each Class I area.\16\ The 1999 RHR also 
provided that States' long-term strategies must include the 
``enforceable emissions limitations, compliance schedules, and other 
measures as necessary to achieve the reasonable progress goals.'' \17\ 
In establishing their long-term strategies, States are required to 
consult with other States that also contribute to visibility impairment 
in a given Class I area and include all measures necessary to obtain 
their shares of the emission reductions needed to meet the RPGs.\18\ 
Section 51.308(d) also contains seven additional factors States must 
consider in formulating their long-term strategies, 40 CFR 
51.308(d)(3)(v), as well as provisions governing monitoring and other 
implementation plan requirements.\19\ Finally, the 1999 RHR required 
states to submit periodic progress reports, which are SIP revisions due 
every five years that contain information on States' implementation of 
their regional haze plans and an assessment of whether anything 
additional is needed to make reasonable progress,\20\ and to consult 
with the Federal Land Manager(s) \21\ (FLMs) responsible for each Class 
I area according to the requirements in CAA 169A(d) and 40 CFR 
51.308(i).
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    \16\ 40 CFR 51.308(d)(1)(i)(B), (d)(2). The EPA established the 
URP framework in the 1999 RHR to provide ``an equitable analytical 
approach'' to assessing the rate of visibility improvement at Class 
I areas across the country. The start point for the URP analysis is 
2004 and the endpoint was calculated based on the amount of 
visibility improvement that was anticipated to result from 
implementation of existing CAA programs over the period from the 
mid-1990s to approximately 2005. Assuming this rate of progress 
would continue into the future, the EPA determined that natural 
visibility conditions would be reached in 60 years, or 2064 (60 
years from the baseline starting point of 2004). However, the EPA 
did not establish 2064 as the year by which the national goal must 
be reached. 64 FR at 35731-32. That is, the URP and the 2064 date 
are not enforceable targets but are rather tools that ``allow for 
analytical comparisons between the rate of progress that would be 
achieved by the state's chosen set of control measures and the 
URP.'' 82 FR 3078, 3084 (January 10, 2017).
    \17\ 40 CFR 51.308(d)(3).
    \18\ 40 CFR 51.308(d)(3)(i), (ii).
    \19\ 40 CFR 51.308(d)(4).
    \20\ See 40 CFR 51.308(g) and (h).
    \21\The EPA's regulation define ``Federal Land Manager'' as 
``the Secretary of the department with authority over the Federal 
Class I area (or the Secretary's designee) or, with respect to 
Roosevelt-Campobello International Park, the Chairman of the 
Roosevelt-Campobello International Park Commission.'' 40 CFR 51.301.
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    On January 10, 2017, the EPA promulgated revisions to the RHR that 
apply for the second and subsequent implementation periods.\22\ The 
2017 rulemaking made several changes to the requirements for regional 
haze SIPs to clarify States' obligations and streamline certain 
regional haze requirements. The revisions to the regional haze program 
for the second and subsequent implementation periods focused on the 
requirement that States' SIPs contain long-term strategies for making 
reasonable progress towards the national visibility goal. The 
reasonable progress requirements as revised in the 2017 rulemaking 
(referred to here as the 2017 RHR Revisions) are codified at 40 CFR 
51.308(f). Among other changes, the 2017 RHR Revisions adjusted the 
deadline for States to submit their second implementation period SIPs 
from July 31, 2018, to July 31, 2021, clarified the order of analysis 
and the relationship between RPGs and the long-term strategy, and 
focused on making visibility improvements on the days with the most 
anthropogenic visibility impairment, as opposed to the days with the 
most visibility impairment overall. The EPA also revised requirements 
of the visibility protection program related to periodic progress 
reports and FLM consultation. The specific requirements applicable to 
second implementation period regional haze SIP submissions are 
addressed in detail below.
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    \22\ 82 FR 3078 (January 10, 2017).
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    The EPA provided guidance to the States for their second 
implementation period SIP submissions in the preamble to the 2017 RHR 
Revisions as well as in subsequent, stand-alone guidance documents. In 
August 2019, the EPA issued ``Guidance on Regional Haze State 
Implementation Plans for the Second Implementation Period'' (``2019 
Guidance'').\23\ On July 8, 2021, the EPA issued a memorandum 
containing ``Clarifications Regarding Regional Haze State 
Implementation Plans for the Second Implementation Period'' (``2021 
Clarifications Memo'').\24\ Additionally, the EPA further clarified the 
recommended procedures for processing ambient visibility data and 
optionally adjusting the URP to account for international anthropogenic 
and prescribed fire impacts in two technical guidance documents: the 
December 2018 ``Technical Guidance on Tracking Visibility Progress for 
the Second Implementation Period of the Regional Haze Program'' (``2018 
Visibility Tracking Guidance''),\25\ and the June 2020 ``Recommendation 
for the Use of Patched and Substituted Data and

[[Page 103740]]

Clarification of Data Completeness for Tracking Visibility Progress for 
the Second Implementation Period of the Regional Haze Program'' and 
associated Technical Addendum (``2020 Data Completeness Memo'').\26\
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    \23\ Guidance on Regional Haze State Implementation Plans for 
the Second Implementation Period, https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period, EPA Office of Air Quality Planning and 
Standards, Research Triangle Park (August 20, 2019).
    \24\ Clarifications Regarding Regional Haze State Implementation 
Plans for the Second Implementation Period, https://www.epa.gov/system/files/documents/2021-07/clarifications-regarding-regional-haze-state-implementation-plans-for-the-second-implementation-period.pdf, EPA Office of Air Quality Planning and Standards, 
Research Triangle Park (July 8, 2021).
    \25\ Technical Guidance on Tracking Visibility Progress for the 
Second Implementation Period of the Regional Haze Program, https://www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional, EPA Office of Air 
Quality Planning and Standards, Research Triangle Park (December 20, 
2018).
    \26\ Recommendation for the Use of Patched and Substituted Data 
and Clarification of Data Completeness for Tracking Visibility 
Progress for the Second Implementation Period of the Regional Haze 
Program, https://www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program, EPA 
Office of Air Quality Planning and Standards, Research Triangle Park 
(June 3, 2020).
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    As explained in the 2021 Clarifications Memo, the EPA intends the 
second implementation period of the regional haze program to secure 
meaningful reductions in visibility impairing pollutants that build on 
the significant progress States have achieved to date. The Agency also 
recognizes that analyses regarding reasonable progress are State-
specific and that, based on States' and sources' individual 
circumstances, what constitutes reasonable reductions in visibility 
impairing pollutants will vary from State-to-State. While there exist 
many opportunities for states to leverage both ongoing and upcoming 
emission reductions under other CAA programs, the Agency expects states 
to undertake rigorous reasonable progress analyses that identify 
further opportunities to advance the national visibility goal 
consistent with the statutory and regulatory requirements.\27\ This is 
consistent with Congress's determination that a visibility protection 
program is needed in addition to the CAA's National Ambient Air Quality 
Standards (NAAQS) and Prevention of Significant Deterioration programs, 
as further emission reductions may be necessary to adequately protect 
visibility in Class I areas throughout the country.\28\
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    \27\ See generally 2021 Clarifications Memo.
    \28\ See, e.g., H.R. Rep No. 95-294 p. 205 (``In determining how 
to best remedy the growing visibility problem in these areas of 
great scenic importance, the committee realizes that as a matter of 
equity, the national ambient air quality standards cannot be revised 
to adequately protect visibility in all areas of the country.''), 
(``the mandatory class I increments of [the PSD program] do not 
adequately protect visibility in class I areas'').
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B. Roles of Agencies in Addressing Regional Haze

    Because the air pollutants and pollution affecting visibility in 
Class I areas can be transported over long distances, successful 
implementation of the regional haze program requires long-term, 
regional coordination among multiple jurisdictions and agencies that 
have responsibility for Class I areas and the emissions that impact 
visibility in those areas. To address regional haze, states need to 
develop strategies in coordination with one another, considering the 
effect of emissions from one jurisdiction on the air quality in 
another. Five regional planning organizations (RPOs),\29\ which include 
representation from state and tribal governments, the EPA, and FLMs, 
were developed in the lead-up to the first implementation period to 
address regional haze. RPOs evaluate technical information to better 
understand how emissions from State and Tribal land impact Class I 
areas across the country, pursue the development of regional strategies 
to reduce emissions of particulate matter and other pollutants leading 
to regional haze, and help states meet the consultation requirements of 
the RHR.
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    \29\ RPOs are sometimes also referred to as ``multi-
jurisdictional organizations,'' or MJOs. For the purposes of this 
notice, the terms RPO and MJO are synonymous.
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    The Western Regional Air Partnership (WRAP), one of the five RPOs 
described above, is a collaborative effort of state governments, tribal 
governments, and various Federal agencies established to initiate and 
coordinate activities associated with the management of regional haze, 
visibility, and other air quality issues in the western corridor of the 
United States. Member states (listed alphabetically) include: Alaska, 
Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, 
North Dakota, Oregon, South Dakota, Utah, Washington, and Wyoming. The 
Federal partner members of WRAP are the EPA, U.S. National Parks 
Service (NPS), U.S. Fish and Wildlife Service (FWS), and U.S. Forest 
Service (USFS). There are also 468 federally recognized Tribes within 
the WRAP region.

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

    Under the CAA and the EPA's regulations, all 50 States, the 
District of Columbia, and the U.S. Virgin Islands are required to 
submit regional haze SIPs satisfying the applicable requirements for 
the second implementation period of the regional haze program by July 
31, 2021. Each state's SIP must contain a long-term strategy for making 
reasonable progress toward meeting the national goal of remedying any 
existing and preventing any future anthropogenic visibility impairment 
in Class I areas.\30\ To this end, section 51.308(f) lays out the 
process by which states determine what constitutes their long-term 
strategies, with the order of the requirements in section 51.308(f)(1) 
through (3) generally mirroring the order of the steps in the 
reasonable progress analysis \31\ and (f)(4) through (6) containing 
additional, related requirements. Broadly speaking, a state first must 
identify the Class I areas within the state and determine the Class I 
areas outside the state in which visibility may be affected by 
emissions from the state. These are the Class I areas that must be 
addressed in the state's long-term strategy.\32\ For each Class I area 
within its borders, a state must then calculate the baseline, current, 
and natural visibility conditions for that area, as well as the 
visibility improvement made to date and the URP.\33\ Each state having 
a Class I area and/or emissions that may affect visibility in a Class I 
area must then develop a long-term strategy that includes the 
enforceable emission limitations, compliance schedules, and other 
measures that are necessary to make reasonable progress in such areas. 
A reasonable progress determination is based on applying the four 
factors in CAA section 169A(g)(1) to sources of visibility-impairing 
pollutants that the state has selected to assess for controls for the 
second implementation period. Additionally, as further explained below, 
the RHR at 40 CFR 51.3108(f)(2)(iv) separately provides five 
``additional factors'' \34\ that states must consider in developing 
their long-term strategies.\35\ A state evaluates potential emission 
reduction measures for those selected sources and determines which are 
necessary to make reasonable progress. Those measures are then 
incorporated into the state's long-term strategy. After a state has 
developed its long-term strategy, it then establishes RPGs for each 
Class I area within its borders by modeling the visibility impacts of 
all reasonable progress controls at the end of the second 
implementation period, i.e., in 2028, as well as the impacts of other 
requirements of the CAA. The RPGs include reasonable progress controls 
not only for sources in the state in which the Class I area is located, 
but also for sources in other states that contribute to visibility 
impairment in that area. The

[[Page 103741]]

RPGs are then compared to the baseline visibility conditions and the 
URP to ensure that progress is being made towards the statutory goal of 
preventing any future and remedying any existing anthropogenic 
visibility impairment in Class I areas.\36\
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    \30\ CAA 169A(b)(2)(B).
    \31\ The EPA explained in the 2017 RHR Revisions that we were 
adopting new regulatory language in 40 CFR 51.308(f) that, unlike 
the structure in 51.308(d), ``tracked the actual planning 
sequence.'' (82 FR 3091, January 10, 2017).
    \32\ See 40 CFR 51.308(f), (f)(2).
    \33\ See 40 CFR 51.308(f)(1).
    \34\ The five ``additional factors'' for consideration in 
section 51.308(f)(2)(iv) are distinct from the four factors listed 
in CAA section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states 
must consider and apply to sources in determining reasonable 
progress.
    \35\ See 40 CFR 51.308(f)(2).
    \36\ 40 CFR 51.308(f)(2)-(3).
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    In addition to satisfying the requirements at 40 CFR 51.308(f) 
related to reasonable progress, the regional haze SIP revisions for the 
second implementation period must address the requirements in section 
51.308(g)(1) through (5) pertaining to periodic reports describing 
progress towards the RPGs,\37\ as well as requirements for FLM 
consultation that apply to all visibility protection SIPs and SIP 
revisions.\38\
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    \37\ 40 CFR 51.308(f)(5).
    \38\ 40 CFR 51.308(i).
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    A state must submit its regional haze SIP and subsequent SIP 
revisions to the EPA according to the requirements applicable to all 
SIP revisions under the CAA and the EPA's regulations.\39\ Upon EPA 
approval, a SIP is enforceable by the Agency and the public under the 
CAA. If the EPA finds that a state fails to make a required SIP 
revision, or if the EPA finds that a state's SIP is incomplete or 
disapproves the SIP, the Agency must promulgate a federal 
implementation plan (FIP) that satisfies the applicable 
requirements.\40\
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    \39\ See CAA 169A(b)(2); CAA 110(a).
    \40\ CAA 110(c)(1).
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A. Identification of Class I Areas

    The first step in developing a regional haze SIP is for a state to 
determine which Class I areas, in addition to those within its borders, 
``may be affected'' by emissions from within the state. In the 1999 
RHR, the EPA determined that all states contribute to visibility 
impairment in at least one Class I area,\41\ and explained that the 
statute and regulations lay out an ``extremely low triggering 
threshold'' for determining ``whether States should be required to 
engage in air quality planning and analysis as a prerequisite to 
determining the need for control of emissions from sources within their 
State.'' \42\
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    \41\ 64 FR 35720-35722.
    \42\ Id. at 35721.
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    A state must determine which Class I areas must be addressed by its 
SIP by evaluating the total emissions of visibility impairing 
pollutants from all sources within the state. While the RHR does not 
require this evaluation to be conducted in any particular manner, the 
EPA's 2019 Guidance provides recommendations for how such an assessment 
might be accomplished, including by, where appropriate, using the 
determinations previously made for the first implementation period.\43\ 
In addition, the determination of which Class I areas may be affected 
by a state's emissions is subject to the requirement in 40 CFR 
51.308(f)(2)(iii) to ``document the technical basis, including 
modeling, monitoring, cost, engineering, and emissions information, on 
which the State is relying to determine the emission reduction measures 
that are necessary to make reasonable progress in each mandatory Class 
I Federal area it affects.''
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    \43\ 2019 Guidance, pp. 8-9.
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B. Calculations of Baseline, Current, and Natural Visibility 
Conditions; Progress to Date; and the Uniform Rate of Progress

    As part of assessing whether a SIP submission for the second 
implementation period is providing for reasonable progress towards the 
national visibility goal, the RHR contains requirements in 40 CFR 
51.308(f)(1) related to tracking visibility improvement over time. The 
requirements of this subsection apply only to states having Class I 
areas within their borders; the required calculations must be made for 
each such Class I area. The EPA's 2018 Visibility Tracking Guidance 
\44\ provides recommendations to assist states in satisfying their 
obligations under section 51.308(f)(1); specifically, in developing 
information on baseline, current, and natural visibility conditions, 
and in making optional adjustments to the URP to account for the 
impacts of international anthropogenic emissions and prescribed fires.
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    \44\ The 2018 Visibility Tracking Guidance references and relies 
on parts of the 2003 Tracking Guidance: ``Guidance for Tracking 
Progress Under the Regional Haze Rule,'' which can be found at 
https://www3.epa.gov/ttnamti1/files/ambient/visible/tracking.pdf.
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    The RHR requires tracking of visibility conditions on two sets of 
days: the clearest and the most impaired days. Visibility conditions 
for both sets of days are expressed as the average deciview index for 
the relevant five-year period (the period representing baseline or 
current visibility conditions). The RHR provides that the relevant sets 
of days for visibility tracking purposes are the 20 percent clearest 
(the 20 percent of monitored days in a calendar year with the lowest 
values of the deciview index) and 20 percent most impaired days (the 20 
percent of monitored days in a calendar year with the highest amounts 
of anthropogenic visibility impairment).\45\ A state must calculate 
visibility conditions for both the 20 percent clearest and 20 percent 
most impaired days for the baseline period of 2000-2004 and the most 
recent five-year period for which visibility monitoring data are 
available (representing current visibility conditions).\46\ States must 
also calculate natural visibility conditions for the clearest and most 
impaired days,\47\ by estimating the conditions that would exist on 
those two sets of days absent anthropogenic visibility impairment.\48\ 
Using all these data, states must then calculate, for each Class I 
area, the amount of progress made since the baseline period (2000-2004) 
and how much improvement is left to achieve to reach natural visibility 
conditions.
---------------------------------------------------------------------------

    \45\ 40 CFR 51.301. This notice also refers to the 20 percent 
clearest and 20 percent most anthropogenically impaired days as the 
``clearest'' and ``most impaired'' or ``most anthropogenically 
impaired'' days, respectively.
    \46\ 40 CFR 51.308(f)(1)(i), (iii).
    \47\ The RHR at 40 CFR 51.308(f)(1)(ii) contains an error 
related to the requirement for calculating two sets of natural 
conditions values. The rule says ``most impaired days or the 
clearest days'' where it should say ``most impaired days and 
clearest days.'' This is an error that was intended to be corrected 
in the 2017 RHR Revisions but did not get corrected in the final 
rule language. This is supported by the preamble text at 82 FR 3098: 
``In the final version of 40 CFR 51.308(f)(1)(ii), an occurrence of 
``or'' has been corrected to ``and'' to indicate that natural 
visibility conditions for both the most impaired days and the 
clearest days must be based on available monitoring information.''
    \48\ 40 CFR 51.308(f)(1)(ii).
---------------------------------------------------------------------------

    Using the data for the set of most impaired days only, states must 
plot a line between visibility conditions in the baseline period and 
natural visibility conditions for each Class I area to determine the 
URP--the amount of visibility improvement, measured in deciviews, that 
would need to be achieved during each implementation period to achieve 
natural visibility conditions by the end of 2064. The URP is used in 
later steps of the reasonable progress analysis for informational 
purposes and to provide a non-enforceable benchmark against which to 
assess a Class I area's rate of visibility improvement.\49\ 
Additionally, in the 2017 RHR Revisions, the EPA provided states the 
option of proposing to adjust the endpoint of the URP to account for 
impacts of anthropogenic sources outside the United States and/or 
impacts of certain types of wildland prescribed fires. These 
adjustments, which must be approved by the EPA, are intended to avoid 
any perception that states should compensate for impacts from 
international

[[Page 103742]]

anthropogenic sources and to give states the flexibility to determine 
that limiting the use of wildland-prescribed fire is not necessary for 
reasonable progress.\50\
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    \49\ Being on or below the URP is not a ``safe harbor''; i.e., 
achieving the URP does not mean that a Class I area is making 
``reasonable progress'' and does not relieve a state from using the 
four statutory factors to determine what level of control is needed 
to achieve such progress. See, e.g., 82 FR 3093.
    \50\ 82 FR 3107 footnote 116.
---------------------------------------------------------------------------

    The EPA's 2018 Visibility Tracking Guidance can be used to help 
satisfy the 40 CFR 51.308(f)(1) requirements, including in developing 
information on baseline, current, and natural visibility conditions, 
and in making optional adjustments to the URP. In addition, the 2020 
Data Completeness Memo provides recommendations on the data 
completeness language referenced in section 51.308(f)(1)(i) and 
provides updated natural conditions estimates for each Class I area.

C. Long-Term Strategy for Regional Haze

    The core component of a regional haze SIP submission is a long-term 
strategy that addresses regional haze in each Class I area within a 
state's borders and each Class I area that may be affected by emissions 
from the state. The long-term strategy ``must include the enforceable 
emissions limitations, compliance schedules, and other measures that 
are necessary to make reasonable progress, as determined pursuant to 
(f)(2)(i) through (iv).'' \51\ The amount of progress that is 
``reasonable progress'' is based on applying the four statutory factors 
in CAA section 169A(g)(1) in an evaluation of potential control options 
for sources of visibility impairing pollutants, which is referred to as 
a ``four-factor'' analysis. The outcome of that analysis is the 
emission reduction measures that a particular source or group of 
sources needs to implement to make reasonable progress towards the 
national visibility goal.\52\ Emission reduction measures that are 
necessary to make reasonable progress may be either new, additional 
control measures for a source, or they may be the existing emission 
reduction measures that a source is already implementing.\53\ Such 
measures must be represented by ``enforceable emissions limitations, 
compliance schedules, and other measures'' (i.e., any additional 
compliance tools) in a state's long-term strategy in its SIP.\54\
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    \51\ 40 CFR 51.308(f)(2).
    \52\ See 40 CFR 51.308(f)(2)(i).
    \53\ See 2019 Guidance, p. 43; 2021 Clarifications Memo, pp. 8-
10.
    \54\ 40 CFR 51.308(f)(2).
---------------------------------------------------------------------------

    Section 51.308(f)(2)(i) provides the requirements for the four-
factor analysis. The first step of this analysis entails selecting the 
sources to be evaluated for emission reduction measures; to this end, 
the RHR requires states to consider ``major and minor stationary 
sources or groups of sources, mobile sources, and area sources'' of 
visibility impairing pollutants for potential four-factor control 
analysis.\55\ A threshold question at this step is which visibility 
impairing pollutants will be analyzed. As the EPA previously explained, 
consistent with the first implementation period, the EPA generally 
expects that each state will analyze at least SO2 and 
NOX in selecting sources and determining control 
measures.\56\ A state that chooses not to consider at least these two 
pollutants should demonstrate why such consideration would be 
unreasonable.\57\
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    \55\ 40 CFR 51.308(f)(2)(i).
    \56\ 2019 Guidance p. 12, 2021 Clarifications Memo p. 4.
    \57\ 2021 Clarifications Memo, p. 4.
---------------------------------------------------------------------------

    While states have the option to analyze all sources, the 2019 
Guidance explains that ``an analysis of control measures is not 
required for every source in each implementation period,'' and that 
``[s]electing a set of sources for analysis of control measures in each 
implementation period is . . . consistent with the Regional Haze Rule, 
which sets up an iterative planning process and anticipates that a 
state may not need to analyze control measures for all its sources in a 
given SIP revision.'' \58\ However, given that source selection is the 
basis of all subsequent control determinations, a reasonable source 
selection process ``should be designed and conducted to ensure that 
source selection results in a set of pollutants and sources the 
evaluation of which has the potential to meaningfully reduce their 
contributions to visibility impairment.'' \59\
---------------------------------------------------------------------------

    \58\ 2019 Guidance, p. 9.
    \59\ 2021 Clarifications Memo, p. 3.
---------------------------------------------------------------------------

    The EPA explained in the 2021 Clarifications Memo that each state 
has an obligation to submit a long-term strategy that addresses the 
regional haze visibility impairment that results from emissions from 
within that state. Thus, source selection should focus on the in-state 
contribution to visibility impairment and be designed to capture a 
meaningful portion of the state's total contribution to visibility 
impairment in Class I areas. A state should not decline to select its 
largest in-state sources on the basis that there are even larger out-
of-state contributors.\60\
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    \60\ 2021 Clarifications Memo, p. 4. Similarly, in responding to 
comments on the 2017 RHR Revisions, the EPA explained that ``[a] 
state should not fail to address its many relatively low-impact 
sources merely because it only has such sources and another state 
has even more low-impact sources and/or some high impact sources.'' 
Responses to Comments on Protection of Visibility: Amendments to 
Requirements for State Plans; Proposed Rule (81 FR 26942, May 4, 
2016), pp. 87-88.
---------------------------------------------------------------------------

    Thus, while states have discretion to choose any source selection 
methodology that is reasonable, whatever choices they make should be 
reasonably explained. To this end, 40 CFR 51.308(f)(2)(i) requires that 
a state's SIP submission include ``a description of the criteria it 
used to determine which sources or groups of sources it evaluated.'' 
The technical basis for source selection, which may include methods for 
quantifying potential visibility impacts such as emissions divided by 
distance metrics, trajectory analyses, residence time analyses, and/or 
photochemical modeling, must also be appropriately documented, as 
required by 40 CFR 51.308(f)(2)(iii).
    Once a state has selected the set of sources, the next step is to 
determine the emissions reduction measures for those sources that are 
necessary to make reasonable progress for the second implementation 
period.\61\ This is accomplished by considering the four factors--``the 
costs of compliance, the time necessary for compliance, and the energy 
and nonair quality environmental impacts of compliance, and the 
remaining useful life of any existing source subject to such 
requirements.'' \62\ The EPA has explained that the four-factor 
analysis is an assessment of potential emission reduction measures 
(i.e., control options) for sources; ``use of the terms `compliance' 
and `subject to such requirements' in section 169A(g)(1) strongly 
indicates that Congress intended the relevant determination to be the 
requirements with which sources would have to comply to satisfy the 
CAA's reasonable progress mandate.'' \63\ Thus, for each source it has 
selected for four-factor analysis,\64\ a state must

[[Page 103743]]

consider a ``meaningful set'' of technically feasible control options 
for reducing emissions of visibility impairing pollutants.\65\ The 2019 
Guidance provides that ``[a] state must reasonably pick and justify the 
measures that it will consider, recognizing that there is no statutory 
or regulatory requirement to consider all technically feasible measures 
or any particular measures. A range of technically feasible measures 
available to reduce emissions would be one way to justify a reasonable 
set.'' \66\
---------------------------------------------------------------------------

    \61\ The CAA provides that, ``[i]n determining reasonable 
progress there shall be taken into consideration'' the four 
statutory factors. CAA 169A(g)(1). However, in addition to four-
factor analyses for selected sources, groups of sources, or source 
categories, a state may also consider additional emissions reduction 
measures for inclusion in its long-term strategy, e.g., from other 
newly adopted, on-the-books, or on-the-way rules and measures for 
sources not selected for four-factor analysis for the second 
planning period.
    \62\ CAA 169A(g)(1).
    \63\ 82 FR 3091.
    \64\ ``Each source'' or ``particular source'' is used here as 
shorthand. While a source-specific analysis is one way of applying 
the four factors, neither the statute nor the RHR requires states to 
evaluate individual sources. Rather, states have ``the flexibility 
to conduct four-factor analyses for specific sources, groups of 
sources or even entire source categories, depending on state policy 
preferences and the specific circumstances of each state.'' 82 FR at 
3088. However, not all approaches to grouping sources for four-
factor analysis are necessarily reasonable; the reasonableness of 
grouping sources in any particular instance will depend on the 
circumstances and the manner in which grouping is conducted. If it 
is feasible to establish and enforce different requirements for 
sources or subgroups of sources, and if relevant factors can be 
quantified for those sources or subgroups, then states should make a 
separate reasonable progress determination for each source or 
subgroup. 2021 Clarifications Memo at 7-8.
    \65\ Id. at 3088.
    \66\ 2019 Guidance, p. 29.
---------------------------------------------------------------------------

    The EPA's 2021 Clarifications Memo provides further guidance on 
what constitutes a reasonable set of control options for consideration: 
``A reasonable four-factor analysis will consider the full range of 
potentially reasonable options for reducing emissions.'' \67\ In 
addition to add-on controls and other retrofits (i.e., new emissions 
reduction measures for sources), the EPA explained that states should 
generally analyze efficiency improvements for sources' existing 
measures as control options in their four-factor analyses, as in many 
cases such improvements are reasonable given that they typically 
involve only additional operation and maintenance costs. Additionally, 
the 2021 Clarifications Memo provides that states that have assumed a 
higher emissions rate than a source has achieved or could potentially 
achieve using its existing measures should also consider lower 
emissions rates as potential control options. That is, a state should 
consider a source's recent actual and projected emission rates to 
determine if it could reasonably attain lower emission rates with its 
existing measures. If so, the state should analyze the lower emission 
rate as a control option for reducing emissions.\68\ The EPA's 
recommendations to analyze potential efficiency improvements and 
achievable lower emission rates apply to both sources that have been 
selected for four-factor analysis and those that have forgone a four-
factor analysis on the basis of existing ``effective controls.'' \69\
---------------------------------------------------------------------------

    \67\ 2021 Clarifications Memo, p. 7.
    \68\ 2021 Clarifications Memo, p. 7.
    \69\ See 2021 Clarifications Memo pp. 5, 10.
---------------------------------------------------------------------------

    After identifying a reasonable set of potential control options for 
the sources it has selected, a state then collects information on the 
four factors with regard to each option identified. The EPA has also 
explained that, in addition to the four statutory factors, states have 
flexibility under the CAA and RHR to reasonably consider visibility 
benefits as an additional factor alongside the four statutory 
factors.\70\ The 2019 Guidance provides recommendations for the types 
of information that can be used to characterize the four factors (with 
or without visibility), as well as ways in which states might 
reasonably consider and balance that information to determine which of 
the potential control options is necessary to make reasonable 
progress.\71\ The 2021 Clarifications Memo contains further guidance on 
how states can reasonably consider modeled visibility impacts or 
benefits in the context of a four-factor analysis.\72\ Specifically, 
the EPA explained that while visibility can reasonably be used when 
comparing and choosing between multiple reasonable control options, it 
should not be used to summarily reject controls that are reasonable 
given the four statutory factors.\73\ Ultimately, while states have 
discretion to reasonably weigh the factors and to determine what level 
of control is needed, section 51.308(f)(2)(i) provides that a state 
``must include in its implementation plan a description of . . . how 
the four factors were taken into consideration in selecting the measure 
for inclusion in its long-term strategy.''
---------------------------------------------------------------------------

    \70\ See, e.g., Responses to Comments on Protection of 
Visibility: Amendments to Requirements for State Plans; Proposed 
Rule (81 FR 26942, May 4, 2016) (December 2016), Docket Number EPA-
HQ-OAR-2015-0531, U.S. Environmental Protection Agency, p. 186; 2019 
Guidance, pp. 36-37.
    \71\ See 2019 Guidance, pp. 30-36.
    \72\ 2021 Clarifications Memo, pp. 12-15.
    \73\ 2021 Clarifications Memo, p. 13.
---------------------------------------------------------------------------

    As explained above, section 51.308(f)(2)(i) requires states to 
determine the emission reduction measures for sources that are 
necessary to make reasonable progress by considering the four factors. 
Pursuant to section 51.308(f)(2), measures that are necessary to make 
reasonable progress towards the national visibility goal must be 
included in a state's long-term strategy and in its SIP.\74\ If the 
outcome of a four-factor analysis is a new, additional emission 
reduction measure for a source, that new measure is necessary to make 
reasonable progress towards remedying existing anthropogenic visibility 
impairment and must be included in the SIP. If the outcome of a four-
factor analysis is that no new measures are reasonable for a source, 
continued implementation of the source's existing measures is generally 
necessary to prevent future emission increases and thus to make 
reasonable progress towards the second part of the national visibility 
goal: preventing future anthropogenic visibility impairment.\75\ That 
is, when the result of a four-factor analysis is that no new measures 
are necessary to make reasonable progress, the source's existing 
measures are generally necessary to make reasonable progress and must 
be included in the SIP. However, there may be circumstances in which a 
state can demonstrate that a source's existing measures are not 
necessary to make reasonable progress. Specifically, if a state can 
demonstrate that a source will continue to implement its existing 
measures and will not increase its emissions rate, it may not be 
necessary to have those measures in the long-term strategy to prevent 
future emissions increases and future visibility impairment. The EPA's 
2021 Clarifications Memo provides further explanation and guidance on 
how states may demonstrate that a source's existing measures are not 
necessary to make reasonable progress.\76\ If the state can make such a 
demonstration, it need not include a source's existing measures in the 
long-term strategy or its SIP.
---------------------------------------------------------------------------

    \74\ States may choose to, but are not required to, include 
measures in their long-term strategies beyond just the emission 
reduction measures that are necessary for reasonable progress. See 
2021 Clarifications Memo at 16. For example, states with smoke 
management programs may choose to submit their smoke management 
plans to EPA for inclusion in their SIPs but are not required to do 
so. See, e.g., 82 FR at 3108-3109 (requirement to consider smoke 
management practices and smoke management programs under 40 CFR 
51.308(f)(2)(iv) does not require states to adopt such practices or 
programs into their SIPs, although they may elect to do so).
    \75\ See CAA 169A(a)(1).
    \76\ See 2021 Clarifications Memo, pp. 8-10.
---------------------------------------------------------------------------

    As with source selection, the characterization of information on 
each of the factors is also subject to the documentation requirement in 
section 51.308(f)(2)(iii). The reasonable progress analysis, including 
source selection, information gathering, characterization of the four 
statutory factors (and potentially visibility), balancing of the four 
factors, and selection of the emission reduction measures that 
represent reasonable progress, is a technically complex exercise, but 
also a flexible one that provides states with bounded discretion to 
design and implement approaches appropriate to their circumstances. 
Given this flexibility, section 51.308(f)(2)(iii) plays an important 
function in requiring a state to document the technical basis for its 
decision making so that the public and the EPA can comprehend and 
evaluate the information and analysis the state relied upon to 
determine what

[[Page 103744]]

emission reduction measures must be in place to make reasonable 
progress. The technical documentation must include the modeling, 
monitoring, cost, engineering, and emissions information on which the 
state relied to determine the measures necessary to make reasonable 
progress. This documentation requirement can be met through the 
provision of and reliance on technical analyses developed through a 
regional planning process, so long as that process and its output has 
been approved by all state participants. In addition to the explicit 
regulatory requirement to document the technical basis of their 
reasonable progress determinations, states are also subject to the 
general principle that those determinations must be reasonably moored 
to the statute.\77\ That is, a state's decisions about the emission 
reduction measures that are necessary to make reasonable progress must 
be consistent with the statutory goal of remedying existing and 
preventing future visibility impairment.
---------------------------------------------------------------------------

    \77\ See Arizona ex rel. Darwin v. U.S. EPA, 815 F.3d 519, 531 
(9th Cir. 2016); Nebraska v. U.S. EPA, 812 F.3d 662, 668 (8th Cir. 
2016); North Dakota v. EPA, 730 F.3d 750, 761 (8th Cir. 2013); 
Oklahoma v. EPA, 723 F.3d 1201, 1206, 1208-10 (10th Cir. 2013); cf. 
also Nat'l Parks Conservation Ass'n v. EPA, 803 F.3d 151, 165 (3d 
Cir. 2015); Alaska Dep't of Envtl. Conservation v. EPA, 540 U.S. 
461, 485, 490 (2004).
---------------------------------------------------------------------------

    The four statutory factors (and potentially visibility) are used to 
determine what emission reduction measures for selected sources must be 
included in a state's long-term strategy for making reasonable 
progress. Additionally, the RHR at 40 CFR 51.3108(f)(2)(iv) separately 
provides five ``additional factors'' \78\ that states must consider in 
developing their long-term strategies: (1) Emission reductions due to 
ongoing air pollution control programs, including measures to address 
reasonably attributable visibility impairment; (2) measures to reduce 
the impacts of construction activities; (3) source retirement and 
replacement schedules; (4) basic smoke management practices for 
prescribed fire used for agricultural and wildland vegetation 
management purposes and smoke management programs; and (5) the 
anticipated net effect on visibility due to projected changes in point, 
area, and mobile source emissions over the period addressed by the 
long-term strategy. The 2019 Guidance provides that a state may satisfy 
this requirement by considering these additional factors in the process 
of selecting sources for four-factor analysis, when performing that 
analysis, or both, and that not every one of the additional factors 
needs to be considered at the same stage of the process.\79\ The EPA 
provided further guidance on the five additional factors in the 2021 
Clarifications Memo, explaining that a state should generally not 
reject cost-effective and otherwise reasonable controls merely because 
there have been emission reductions since the first planning period 
owing to other ongoing air pollution control programs or merely because 
visibility is otherwise projected to improve at Class I areas. 
Additionally, states generally should not rely on these additional 
factors to summarily assert that the state has already made sufficient 
progress and, therefore, no sources need to be selected or no new 
controls are needed regardless of the outcome of four-factor 
analyses.\80\
---------------------------------------------------------------------------

    \78\ The five ``additional factors'' for consideration in 
section 51.308(f)(2)(iv) are distinct from the four factors listed 
in CAA section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states 
must consider and apply to sources in determining reasonable 
progress.
    \79\ See 2019 Guidance, p. 21.
    \80\ 2021 Clarifications Memo, p. 13.
---------------------------------------------------------------------------

    Because the air pollution that causes regional haze crosses state 
boundaries, section 51.308(f)(2)(ii) requires a state to consult with 
other states that also have emissions that are reasonably anticipated 
to contribute to visibility impairment in a given Class I area. 
Consultation allows for each state that impacts visibility in an area 
to share whatever technical information, analyses, and control 
determinations may be necessary to develop coordinated emission 
management strategies. This coordination may be managed through inter- 
and intra-RPO consultation and the development of regional emissions 
strategies; additional consultations between states outside of RPO 
processes may also occur. If a state, pursuant to consultation, agrees 
that certain measures (e.g., a certain emission limitation) are 
necessary to make reasonable progress at a Class I area, it must 
include those measures in its SIP.\81\ Additionally, the RHR requires 
that states that contribute to visibility impairment at the same Class 
I area consider the emission reduction measures the other contributing 
states have identified as being necessary to make reasonable progress 
for their own sources.\82\ If a state has been asked to consider or 
adopt certain emission reduction measures, but ultimately determines 
those measures are not necessary to make reasonable progress, that 
state must document in its SIP the actions taken to resolve the 
disagreement.\83\ The EPA will consider the technical information and 
explanations presented by the submitting state and the state with which 
it disagrees when considering whether to approve the state's SIP.\84\ 
Under all circumstances, a state must document in its SIP submission 
all substantive consultations with other contributing states.\85\
---------------------------------------------------------------------------

    \81\ 40 CFR 51.308(f)(2)(ii)(A).
    \82\ 40 CFR 51.308(f)(2)(ii)(B).
    \83\ 40 CFR 51.308(f)(2)(ii)(C).
    \84\ See id.; 2019 Guidance, p. 53.
    \85\ 40 CFR 51.308(f)(2)(ii)(C).
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D. Reasonable Progress Goals

    Reasonable progress goals ``measure the progress that is projected 
to be achieved by the control measures states have determined are 
necessary to make reasonable progress based on a four-factor 
analysis.'' \86\ Their primary purpose is to assist the public and the 
EPA in assessing the reasonableness of states' long-term strategies for 
making reasonable progress towards the national visibility goal.\87\ 
States in which Class I areas are located must establish two RPGs, both 
in deciviews--one representing visibility conditions on the clearest 
days and one representing visibility on the most anthropogenically 
impaired days--for each area within their borders.\88\ The two RPGs are 
intended to reflect the projected impacts, on the two sets of days, of 
the emission reduction measures the state with the Class I area, as 
well as all other contributing states, have included in their long-term 
strategies for the second implementation period.\89\ The RPGs also 
account for the projected impacts of implementing other CAA 
requirements, including non-SIP based requirements. Because RPGs are 
the modeled result of the measures in states' long-term strategies (as 
well as other measures required under the CAA), they cannot be 
determined before states have conducted their four-factor analyses and 
determined the control measures that are necessary to make reasonable 
progress.\90\
---------------------------------------------------------------------------

    \86\ 82 FR 3091.
    \87\ See 40 CFR 51.308(f)(3)(iii)-(iv).
    \88\ 40 CFR 51.308(f)(3)(i).
    \89\ RPGs are intended to reflect the projected impacts of the 
measures all contributing states include in their long-term 
strategies. However, due to the timing of analyses, control 
determinations by other states, and other on-going emissions 
changes, a particular state's RPGs may not reflect all control 
measures and emissions reductions that are expected to occur by the 
end of the implementation period. The 2019 Guidance provides 
recommendations for addressing the timing of RPG calculations when 
states are developing their long-term strategies on disparate 
schedules, as well as for adjusting RPGs using a post-modeling 
approach. 2019 Guidance, pp. 47-48.
    \90\ See 2021 Clarifications Memo p. 6.
---------------------------------------------------------------------------

    For the second implementation period, the RPGs are set for 2028. 
Reasonable progress goals are not

[[Page 103745]]

enforceable targets; \91\ rather, they ``provide a way for the states 
to check the projected outcome of the [long-term strategy] against the 
goals for visibility improvement.'' \92\ While states are not legally 
obligated to achieve the visibility conditions described in their RPGs, 
section 51.308(f)(3)(i) requires that ``[t]he long-term strategy and 
the reasonable progress goals must provide for an improvement in 
visibility for the most impaired days since the baseline period and 
ensure no degradation in visibility for the clearest days since the 
baseline period.'' Thus, states are required to have emission reduction 
measures in their long-term strategies that are projected to achieve 
visibility conditions on the most impaired days that are better than 
the baseline period and shows no degradation on the clearest days 
compared to the clearest days from the baseline period. The baseline 
period for the purpose of this comparison is the baseline visibility 
condition--the annual average visibility condition for the period 2000-
2004.\93\
---------------------------------------------------------------------------

    \91\ 40 CFR 51.308(f)(3)(iii).
    \92\ 2019 Guidance, p. 46.
    \93\ See 40 CFR 51.308(f)(1)(i), 82 FR 3097-98.
---------------------------------------------------------------------------

    So that RPGs may also serve as a metric for assessing the amount of 
progress a state is making towards the national visibility goal, the 
RHR requires states with Class I areas to compare the 2028 RPG for the 
most impaired days to the corresponding point on the URP line 
(representing visibility conditions in 2028 if visibility were to 
improve at a linear rate from conditions in the baseline period of 
2000-2004 to natural visibility conditions in 2064). If the most 
impaired days RPG in 2028 is above the URP (i.e., if visibility 
conditions are improving more slowly than the rate described by the 
URP), each state that contributes to visibility impairment in the Class 
I area must demonstrate, based on the four-factor analysis required 
under 40 CFR 51.308(f)(2)(i), that no additional emission reduction 
measures would be reasonable to include in its long-term strategy.\94\ 
To this end, 40 CFR 51.308(f)(3)(ii) requires that each state 
contributing to visibility impairment in a Class I area that is 
projected to improve more slowly than the URP provide ``a robust 
demonstration, including documenting the criteria used to determine 
which sources or groups [of] sources were evaluated and how the four 
factors required by paragraph (f)(2)(i) were taken into consideration 
in selecting the measures for inclusion in its long-term strategy.'' 
The 2019 Guidance provides suggestions about how such a ``robust 
demonstration'' might be conducted.\95\
---------------------------------------------------------------------------

    \94\ 40 CFR 51.308(f)(3)(ii).
    \95\ See 2019 Guidance, pp. 50-51.
---------------------------------------------------------------------------

    The 2017 RHR, 2019 Guidance, and 2021 Clarifications Memo also 
explain that projecting an RPG that is on or below the URP based on 
only on-the-books and/or on-the-way control measures (i.e., control 
measures already required or anticipated before the four-factor 
analysis is conducted) is not a ``safe harbor'' from the CAA's and 
RHR's requirement that all states must conduct a four-factor analysis 
to determine what emission reduction measures constitute reasonable 
progress. The URP is a planning metric used to gauge the amount of 
progress made thus far and the amount left before reaching natural 
visibility conditions. However, the URP is not based on consideration 
of the four statutory factors and therefore cannot answer the question 
of whether the amount of progress being made in any particular 
implementation period is ``reasonable progress.'' \96\
---------------------------------------------------------------------------

    \96\ See 82 FR 3093, 3099-3100; 2019 Guidance, p. 22; 2021 
Clarifications Memo, pp. 15-16.
---------------------------------------------------------------------------

E. Monitoring Strategy and Other State Implementation Plan Requirements

    Section 51.308(f)(6) requires states to have certain strategies and 
elements in place for assessing and reporting on visibility. Individual 
requirements under this subsection apply either to states with Class I 
areas within their borders, states with no Class I areas but that are 
reasonably anticipated to cause or contribute to visibility impairment 
in any Class I area, or both. A state with Class I areas within its 
borders must submit with its SIP revision a monitoring strategy for 
measuring, characterizing, and reporting regional haze visibility 
impairment that is representative of all Class I areas within the 
state. SIP revisions for such states must also provide for the 
establishment of any additional monitoring sites or equipment needed to 
assess visibility conditions in Class I areas, as well as reporting of 
all visibility monitoring data to the EPA at least annually. Compliance 
with the monitoring strategy requirement may be met through a state's 
participation in the Interagency Monitoring of Protected Visual 
Environments (IMPROVE) monitoring network, which is used to measure 
visibility impairment caused by air pollution at the 156 Class I areas 
covered by the visibility program.\97\ The Interagency Monitoring of 
Protected Visual Environments (IMPROVE) monitoring data is used to 
determine the 20 percent most anthropogenically impaired and 20 percent 
clearest sets of days every year at each Class I area and tracks 
visibility impairment over time.
---------------------------------------------------------------------------

    \97\ 40 CFR 51.308(f)(6), (f)(6)(i), (f)(6)(iv).
---------------------------------------------------------------------------

    All states' SIPs must provide for procedures by which monitoring 
data and other information are used to determine the contribution of 
emissions from within the state to regional haze visibility impairment 
in affected Class I areas.\98\ Section 51.308(f)(6)(v) further requires 
that all states' SIPs provide for a statewide inventory of emissions of 
pollutants that are reasonably anticipated to cause or contribute to 
visibility impairment in any Class I area; the inventory must include 
emissions for the most recent year for which data are available and 
estimates of future projected emissions. States must also include 
commitments to update their inventories periodically. The inventories 
themselves do not need to be included as elements in the SIP and are 
not subject to the EPA review as part of the Agency's evaluation of a 
SIP revision.\99\ All states' SIPs must also provide for any other 
elements, including reporting, recordkeeping, and other measures, that 
are necessary for states to assess and report on visibility.\100\ Per 
the 2019 Guidance, a state may note in its regional haze SIP that its 
compliance with the Air Emissions Reporting Rule (AERR) in 40 CFR part 
51 Subpart A satisfies the requirement to provide for an emissions 
inventory for the most recent year for which data are available. To 
satisfy the requirement to provide estimates of future projected 
emissions, a state may explain in its SIP how projected emissions were 
developed for use in establishing RPGs for its own and nearby Class I 
areas.\101\
---------------------------------------------------------------------------

    \98\ 40 CFR 51.308(f)(6)(ii), (iii).
    \99\ See ``Step 8: Additional requirements for regional haze 
SIPs'' in 2019 Guidance, p. 55.
    \100\ 40 CFR 51.308(f)(6)(vi).
    \101\ Id.
---------------------------------------------------------------------------

    Separate from the requirements related to monitoring for regional 
haze purposes under 40 CFR 51.308(f)(6), the RHR also contains a 
requirement at 40 CFR 51.308(f)(4) related to any additional monitoring 
that may be needed to address visibility impairment in Class I areas 
from a single source or a small group of sources. This is called 
``reasonably attributable visibility impairment.'' \102\ Under this 
provision, if the EPA or the FLM of an affected Class I area has 
advised a state that additional monitoring is needed to assess 
reasonably attributable visibility

[[Page 103746]]

impairment, the state must include in its SIP revision for the second 
implementation period an appropriate strategy for evaluating such 
impairment.
---------------------------------------------------------------------------

    \102\ The EPA's visibility protection regulations define 
``reasonably attributable visibility impairment'' as ``visibility 
impairment that is caused by the emission of air pollutants from 
one, or a small number of sources.'' 40 CFR 51.301.
---------------------------------------------------------------------------

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

    Section 51.308(f)(5) requires a state's regional haze SIP revision 
to address the requirements of paragraphs 40 CFR 51.308(g)(1) through 
(5) so that the plan revision due in 2021 will serve also as a progress 
report addressing the period since submission of the progress report 
for the first implementation period. The regional haze progress report 
requirement is designed to inform the public and the EPA about a 
state's implementation of its existing long-term strategy and whether 
such implementation is in fact resulting in the expected visibility 
improvement.\103\ To this end, every state's SIP revision for the 
second implementation period is required to describe the status of 
implementation of all measures included in the state's long-term 
strategy, including BART and reasonable progress emission reduction 
measures from the first implementation period, and the resulting 
emissions reductions.\104\
---------------------------------------------------------------------------

    \103\ See 81 FR 26942, 26950 (May 4, 2016); 82 FR 3119 (January 
10, 2017).
    \104\ 40 CFR 51.308(g)(1) and (2).
---------------------------------------------------------------------------

    A core component of the progress report requirements is an 
assessment of changes in visibility conditions on the clearest and most 
impaired days. For second implementation period progress reports, 
section 51.308(g)(3) requires states with Class I areas within their 
borders to first determine current visibility conditions for each area 
on the most impaired and clearest days,\105\ and then to calculate the 
difference between those current conditions and baseline (2000-2004) 
visibility conditions to assess progress made to date.\106\ States must 
also assess the changes in visibility impairment for the most impaired 
and clearest days since they submitted their first implementation 
period progress reports.\107\ Since different states submitted their 
first implementation period progress reports at different times, the 
starting point for this assessment will vary state by state.
---------------------------------------------------------------------------

    \105\ 40 CFR 51.308(g)(3)(i)(B).
    \106\ See 40 CFR 51.308(g)(3)(ii)(B).
    \107\ See 40 CFR 51.308(g)(3)(iii)(B), (f)(5).
---------------------------------------------------------------------------

    Similarly, states must provide analyses tracking the change in 
emissions of pollutants contributing to visibility impairment from all 
sources and activities within the state over the period since they 
submitted their first implementation period progress reports.\108\ 
Changes in emissions should be identified by the type of source or 
activity. Section 51.308(g)(5) also addresses changes in emissions 
since the period addressed by the previous progress report and requires 
states' SIP revisions to include an assessment of any significant 
changes in anthropogenic emissions within or outside the state. This 
assessment must explain whether these changes in emissions were 
anticipated and whether they have limited or impeded progress in 
reducing emissions and improving visibility relative to what the state 
projected based on its long-term strategy for the first implementation 
period.
---------------------------------------------------------------------------

    \108\ See 40 CFR 51.308(g)(4), (f)(5).
---------------------------------------------------------------------------

G. Requirements for State and Federal Land Manager Coordination

    Clean Air Act section 169A(d) requires that before a state holds a 
public hearing on a proposed regional haze SIP revision, it must 
consult with the appropriate FLM or FLMs; pursuant to that 
consultation, the state must include a summary of the FLMs' conclusions 
and recommendations in the notice to the public. Consistent with this 
statutory requirement, the RHR also requires that states ``provide the 
[FLM] with an opportunity for consultation, in person and at a point 
early enough in the State's policy analyses of its long-term strategy 
emission reduction obligation so that information and recommendations 
provided by the [FLM] can meaningfully inform the State's decisions on 
the long-term strategy.'' \109\ Consultation that occurs 120 days prior 
to any public hearing or public comment opportunity will be deemed 
``early enough,'' but the RHR provides that in any event the 
opportunity for consultation must be provided at least 60 days before a 
public hearing or comment opportunity. This consultation must include 
the opportunity for the FLMs to discuss their assessment of visibility 
impairment in any Class I area and their recommendations on the 
development and implementation of strategies to address such 
impairment.\110\ For the EPA to evaluate whether FLM consultation 
meeting the requirements of the RHR has occurred, the SIP submission 
should include documentation of the timing and content of such 
consultation. The SIP revision submitted to the EPA must also describe 
how the state addressed any comments provided by the FLMs.\111\ 
Finally, a SIP revision must provide procedures for continuing 
consultation between the state and FLMs regarding the state's 
visibility protection program, including development and review of SIP 
revisions, five-year progress reports, and the implementation of other 
programs having the potential to contribute to impairment of visibility 
in Class I areas.\112\
---------------------------------------------------------------------------

    \109\ 40 CFR 51.308(i)(2).
    \110\ 40 CFR 51.308(i)(2).
    \111\ 40 CFR 51.308(i)(3).
    \112\ 40 CFR 51.308(i)(4).
---------------------------------------------------------------------------

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

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

    California submitted its initial regional haze plan under 40 CFR 
51.308 to the EPA on March 16, 2009 (hereinafter ``2009 Submittal''). 
The EPA approved the 2009 Submittal on June 14, 2011.\113\ On June 16, 
2014, California submitted its Progress Report to meet the requirements 
of 40 CFR 51.308(g) and (h). The EPA approved the Progress Report on 
April 1, 2015.\114\
---------------------------------------------------------------------------

    \113\ 76 FR 34608.
    \114\ 80 FR 17327.
---------------------------------------------------------------------------

B. California's Second Implementation Period SIP Submission

    In accordance with CAA sections 169A and the RHR at 40 CFR 
51.308(f), on August 9, 2022, CARB submitted a revision to the 
California SIP to address its regional haze obligations for the second 
implementation period, which runs through 2028. California made its 
2022 Regional Haze Plan available for public comment on May 13, 2022. 
CARB received and responded to public comments.\115\
---------------------------------------------------------------------------

    \115\ Public comments and CARB responses are available on the 
CARB website at https://ww2.arb.ca.gov/sites/default/files/2023-01/RegionalHazeResponseToPublicComments.pdf.
---------------------------------------------------------------------------

    The following sections describe the Plan, including analyses 
conducted by the WRAP and CARB, CARB's assessment of progress made 
since the first implementation period in reducing emissions of 
visibility impairing pollutants, and the visibility improvement 
progress at its Class I areas and nearby Class I areas. This notice 
also contains the EPA's evaluation of the Plan against the requirements 
of the CAA and RHR for the second implementation period of the regional 
haze program.

C. Identification of Class I Areas

    Section 169A(b)(2) of the CAA requires each state in which any 
Class I area is located or ``the emissions from which may reasonably be 
anticipated to cause or contribute to any impairment

[[Page 103747]]

of visibility'' in a Class I area to have a plan for making reasonable 
progress toward the national visibility goal. The RHR implements this 
statutory requirement at 40 CFR 51.308(f), which provides that each 
state's plan ``must address regional haze in each mandatory Class I 
Federal area located within the State and in each mandatory Class I 
Federal area located outside the State that may be affected by 
emissions from within the State,'' and (f)(2), which requires each 
state's plan to include a long-term strategy that addresses regional 
haze in such Class I areas.
    The EPA explained in the 1999 RHR preamble that the CAA section 
169A(b)(2) requirement that states submit SIPs to address visibility 
impairment establishes ``an `extremely low triggering threshold' in 
determining which States should submit SIPs for regional haze.'' \116\ 
In concluding that each of the contiguous 48 states and the District of 
Columbia meet this threshold,\117\ the EPA relied on ``a large body of 
evidence demonstrat[ing] that long-range transport of fine PM 
contributes to regional haze,'' \118\ including modeling studies that 
``preliminarily demonstrated that each State not having a Class I area 
had emissions contributing to impairment in at least one downwind Class 
I area.'' \119\ In addition to the technical evidence supporting a 
conclusion that each state contributes to existing visibility 
impairment, the EPA also explained that the second half of the national 
visibility goal--preventing future visibility impairment--requires 
having a framework in place to address future growth in visibility-
impairing emissions and makes it inappropriate to ``establish criteria 
for excluding States or geographic areas from consideration as 
potential contributors to regional haze visibility impairment.'' \120\ 
Thus, the EPA concluded that the agency's ``statutory authority and the 
scientific evidence are sufficient to require all States to develop 
regional haze SIPs to ensure the prevention of any future impairment of 
visibility, and to conduct further analyses to determine whether 
additional control measures are needed to ensure reasonable progress in 
remedying existing impairment in downwind Class I areas.'' \121\ The 
EPA's 2017 revisions to the RHR did not disturb this conclusion.\122\
---------------------------------------------------------------------------

    \116\ 64 FR at 35721.
    \117\ The EPA determined that ``there is more than sufficient 
evidence to support our conclusion that emissions from each of the 
48 contiguous states and the District of Columbia may reasonably be 
anticipated to cause or contribute to visibility impairment in a 
Class I area.'' 64 FR at 35721. Hawaii, Alaska, and the U.S. Virgin 
Islands must also submit regional haze plans because they contain 
Class I areas.
    \118\ Id.
    \119\ Id. at 35722.
    \120\ Id. at 35721.
    \121\ Id. at 35722.
    \122\ 82 FR at 3094.
---------------------------------------------------------------------------

    California has 29 Class I areas within its borders: Redwood 
National Park; Marble Mountain Wilderness; Lava Beds National Monument; 
South Warner Wilderness; Thousand Lakes Wilderness; Lassen Volcanic 
National Park; Caribou Wilderness; Yolla Bolly-Middle Eel Wilderness 
(includes land managed by the U.S. Bureau of Land Management); Point 
Reyes National Seashore; Ventana Wilderness; Pinnacles National 
Monument; Desolation Wilderness; Mokelumne Wilderness; Emigrant 
Wilderness; Hoover Wilderness; Yosemite National Park; Ansel Adams 
Wilderness; Kaiser Wilderness; John Muir Wilderness; Kings Canyon 
National Park; Sequoia National Park; Dome Lands Wilderness; San Rafael 
Wilderness; San Gabriel Wilderness; Cucamonga Wilderness; San Gorgonio 
Wilderness; San Jacinto Wilderness; Agua Tibia Wilderness; and Joshua 
Tree National Park.
    In its submission, CARB also briefly assessed the contribution of 
emissions from California to visibility impairment at Class I areas in 
three neighboring states: Oregon, Nevada, and Arizona.\123\ CARB noted 
that the projected share of ammonium nitrate and ammonium sulfate 
attributable to California sources ranges from 0.1 to 1.7 percent and 
0.1 to 1.0 percent, respectively, of the total light extinction budgets 
at Class I areas in neighboring states.\124\ These total light 
extinction budgets include international and natural emissions, which 
cannot be addressed by states, and therefore do not provide a 
meaningful assessment of the contribution of California's sources 
relative to other U.S. anthropogenic sources. CARB also did not 
consider whether emissions from California may affect Class I areas in 
any states other than its three neighboring states.\1\
---------------------------------------------------------------------------

    \123\ 2022 California Regional Haze Plan, pp. 64-68.
    \124\ Id. at 64.
---------------------------------------------------------------------------

    As discussed in further detail below, the EPA is proposing to find 
that the 2022 California Regional Haze Plan does not fully meet the 
requirements of 40 CFR 51.308(f)(2) related to the development of a 
long-term strategy. Relatedly, the State failed to identify specific 
out-of-state Class I areas may be affected by emissions from 
California.

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

    Section 51.308(f)(1) requires states to determine the following for 
``each mandatory Class I Federal area located within the State'': 
baseline visibility conditions for the most impaired and clearest days, 
natural visibility conditions for the most impaired and clearest days, 
progress to date for the most impaired and clearest days, the 
differences between current visibility conditions and natural 
visibility conditions, and the URP. This section also provides the 
option for states to propose adjustments to the URP line for a Class I 
area to account for visibility impacts from anthropogenic sources 
outside the United States and/or the impacts from wildland prescribed 
fires that were conducted for certain, specified objectives.\125\
---------------------------------------------------------------------------

    \125\ 40 CFR 51.308(f)(1)(vi)(B).
---------------------------------------------------------------------------

    In the 2022 California Regional Haze Plan, CARB used visibility 
data from IMPROVE monitoring sites for 2000-2004 for baseline 
visibility.\126\ CARB also obtained visibility data from IMPROVE 
monitoring data for 2014-2018, which it used to represent current 
visibility conditions. CARB determined natural visibility by estimating 
the natural concentrations of visibility-impairing pollutants and then 
calculating total light extinction with the IMPROVE algorithm. 
Comparison of baseline conditions to natural visibility conditions 
shows the improvement necessary to attain natural visibility by 2064 
measured in deciviews of improvement per year that represents the URP. 
The calculations of baseline, current, and natural visibility 
conditions, as well as the progress to date and differences between 
current visibility condition and natural visibility condition can be 
found in Chapter 2 of the 2022 California Regional Haze Plan and are 
summarized in tables 1 and 2 of this document.
---------------------------------------------------------------------------

    \126\ Plan, p. 22.

[[Page 103748]]



                                Table 1--Visibility Conditions for Clearest Days
                                                      [dv]
----------------------------------------------------------------------------------------------------------------
                                                                               Progress
          IMPROVE site               Class I areas     Baseline     Current     to date     Natural   Difference
----------------------------------------------------------------------------------------------------------------
LABE1...........................  Lava Beds National         3.2         2.5         0.7         1.3         1.2
                                   Monument.
                                  South Warner
                                   Wilderness Area.
REDW1...........................  Redwood National           6.1         5.3         0.8         3.5         1.8
                                   Park.
TRIN1...........................  Marble Mountain            3.4         3.1         0.3         1.2         1.9
                                   Wilderness.
                                  Yolla Bolly-Middle
                                   Eel Wilderness
                                   Area.
LAVO1...........................  Caribou Wilderness         2.7         2.2         0.5         1.0         1.2
                                   Area.
                                  Lassen Volcanic
                                   National Park.
                                  Thousand Lakes
                                   Wilderness.
BLIS1...........................  Desolation                 2.5         1.8         0.7         0.4         1.4
                                   Wilderness Area.
                                  Mokelumne
                                   Wilderness Area.
PORE1...........................  Point Reyes               10.5         8.2         2.3         4.8         3.4
                                   National Seashore.
YOSE1...........................  Emigrant                   3.4         2.9         0.5         1.0         1.9
                                   Wilderness Area.
                                  Yosemite National
                                   Park.
HOOV1...........................  Hoover Wilderness          1.4         1.0         0.4         0.1         0.9
                                   Area.
KAIS1...........................  Ansel Adams                2.3         1.5         0.8         0.0         1.5
                                   Wilderness Area.
                                  John Muir
                                   Wilderness Area.
                                  Kaiser Wilderness
                                   Area.
PINN1...........................  Pinnacles National         8.9         7.7         1.2         3.5         4.2
                                   Park.
                                  Ventana Wilderness
                                   Area.
SEQU1...........................  Kings Canyon               8.8         7.0         1.8         2.3         4.7
                                   National Park.
                                  Sequoia National
                                   Park.
RAFA1...........................  San Rafael                 6.5         4.9         1.6         1.8         3.1
                                   Wilderness Area.
DOME1...........................  Domeland                   5.1         4.4         0.7         1.2         3.2
                                   Wilderness Area.
SAGA1...........................  Cucamonga                  4.8         2.8         2.0         0.4         2.4
                                   Wilderness Area.
                                  San Gabriel
                                   Wilderness Area.
SAGO1...........................  San Gorgonio               5.4         3.3         2.1         1.2         2.1
                                   Wilderness Area.
                                  San Jacinto
                                   Wilderness Area.
JOSH1...........................  Joshua Tree                6.1         4.7         1.4         1.7         3.0
                                   National Park.
AGTI1...........................  Agua Tibia                 9.6         7.0         2.6         2.9         4.1
                                   Wilderness Area.
----------------------------------------------------------------------------------------------------------------
Source: 2022 California Regional Haze Plan, 38, Tables 2-3, 2-4, 2-6, 2-7, 2-9 and 2-10. Baseline conditions are
  for 2000-2004. Current Conditions are for 2014-2018. Progress to date is Baseline Minus Current. Difference is
  Current minus Natural Conditions.


                              Table 2--Visibility Conditions for Most-Impaired Days
                                                      [dv]
----------------------------------------------------------------------------------------------------------------
                                                                               Progress
          IMPROVE site               Class I areas     Baseline     Current     to date     Natural   Difference
----------------------------------------------------------------------------------------------------------------
LABE1...........................  Lava Beds National        11.3         9.7         1.6         6.2         3.5
                                   Monument.
                                  South Warner
                                   Wilderness Area.
REDW1...........................  Redwood National          13.7        12.6         1.1         8.6         4.0
                                   Park.
TRIN1...........................  Marble Mountain           11.9        10.4         1.5         6.5         3.9
                                   Wilderness.
                                  Yolla Bolly-Middle
                                   Eel Wild. Area.
LAVO1...........................  Caribou Wilderness        11.5        10.2         1.3         6.1         4.1
                                   Area.
                                  Lassen Volcanic
                                   National Park.
                                  Thousand Lakes
                                   Wilderness.
BLIS1...........................  Desolation                10.1         9.3         0.8         4.9         4.4
                                   Wilderness Area.
                                  Mokelumne
                                   Wilderness Area.
PORE1...........................  Point Reyes               19.4        15.3         4.1         9.7         5.6
                                   National Seashore.
YOSE1...........................  Emigrant                  13.5        11.6         1.9         6.3         5.3
                                   Wilderness Area.
                                  Yosemite National
                                   Park.
HOOV1...........................  Hoover Wilderness          8.9         7.8         1.1         4.9         2.9
                                   Area.
KAIS1...........................  Ansel Adams               12.9        11.0         1.9         6.1         4.9
                                   Wilderness Area.
                                  John Muir
                                   Wilderness Area.
                                  Kaiser Wilderness
                                   Area.
PINN1...........................  Pinnacles National        17.0        14.1         2.9         6.9         7.2
                                   Park.
                                  Ventana Wilderness
                                   Area.
SEQU1...........................  Kings Canyon              23.2        18.4         4.8         6.3        12.1
                                   National Park.
                                  Sequoia National
                                   Park.
RAFA1...........................  San Rafael                17.3        14.1         3.2         6.8         7.3
                                   Wilderness Area.
DOME1...........................  Domeland                  17.2        15.1         2.1         6.2         8.9
                                   Wilderness Area.
SAGA1...........................  Cucamonga                 17.9        13.2         4.7         6.1         7.1
                                   Wilderness Area.
                                  San Gabriel
                                   Wilderness Area.
SAGO1...........................  San Gorgonio              20.4        14.4         6.0         6.2         8.2
                                   Wilderness Area.
                                  San Jacinto
                                   Wilderness Area.
JOSH1...........................  Joshua Tree               17.7        12.9         4.8         6.1         6.8
                                   National Park.

[[Page 103749]]

 
AGTI1...........................  Agua Tibia                21.6        16.3         5.3         7.7         8.6
                                   Wilderness Area.
----------------------------------------------------------------------------------------------------------------
Source: 2022 California Regional Haze Plan, Tables 2-3, 2-5, 2-6, 2-8, 2-9 and 2-11. Baseline conditions are for
  2000-2004. Current Conditions are for 2014-2018. Progress to date is Baseline Minus Current. Difference is
  Current minus Natural Conditions.

    CARB chose to adjust its URP for international anthropogenic 
impacts and to account for the impacts of wildland prescribed fires 
using adjustments developed by the WRAP.\127\ The WRAP/WAQS Regional 
Haze modeling platform used scaled 2014 NEI wildland prescribed fire 
data for purposes of calculating the URP adjustments. WRAP used the 
results from the CAMx 2028OTBa2 High-Level Source Apportionment run to 
obtain concentrations due to international emissions and to prescribed 
fire. These concentrations were then used in a relative sense to 
estimate the contributions for use in adjusting the URP. That is, the 
modeled relative effect of removing their emissions (relative response 
factors) was applied to projections of 2028 concentrations. The 
resulting concentration decrease was taken as the contribution of these 
sources. The international and prescribed fire contributions were 
therefore calculated in a fashion consistent with each other and with 
the 2028 projections. This approach is consistent with the default 
method described in the EPA's September 2019 regional haze modeling 
Technical Support Document (``EPA 2019 Modeling TSD'') \128\ and with 
the source apportionment approach described in the EPA's 2018 
Visibility Tracking Guidance.\129\ Two different adjusted glidepath 
options, ``International Emissions Only (A)'' and ``International 
Emissions + Wildland Rx Fire (B)'', were made available on the WRAP 
Technical Support System (TSS) \130\ to adjust the URP glidepath end 
points projections at 2064 for Class I Federal areas on the most 
impaired days.
---------------------------------------------------------------------------

    \127\ Plan, pp. 51, 135-136.
    \128\ Memorandum from Richard A. Wayland, Director, Air Quality 
Assessment Division, EPA, to Regional Air Division Directors, 
Subject: ``Availability of Modeling Data and Associated Technical 
Support Document for the EPA's Updated 2028 Visibility Air Quality 
Modeling,'' September 19, 2019, available at https://www.epa.gov/visibility/technical-support-document-epas-updated-2028-regional-haze-modeling.
    \129\ Memorandum from Richard A. Wayland, Director, Air Quality 
Assessment Division, EPA, to Regional Air Division Directors, 
Subject: ``Technical Guidance on Tracking Visibility Progress for 
the Second Implementation Period of the Regional Haze Program,'' 
December 20, 2018, available at https://www.epa.gov/sites/default/files/2018-12/documents/technical_guidance_tracking_visibility_progress.pdf.
    \130\ WRAP Technical Support System, http://views.cira.colostate.edu/tssv2/.

                                       Table 3--URP for Most-Impaired Days
                                                    [dv/year]
----------------------------------------------------------------------------------------------------------------
                IMPROVE site                           Class I area            Unadjusted URP     Adjusted URP
----------------------------------------------------------------------------------------------------------------
LABE1.......................................  Lava Beds National Monument...              0.09              0.07
                                              South Warner Wilderness Area..
REDW1.......................................  Redwood National Park.........              0.09              0.07
TRIN1.......................................  Marble Mountain Wilderness                  0.09              0.05
                                               Area.
                                              Yolla Bolly-Middle Eel
                                               Wilderness Area.
LAVO1.......................................  Thousand Lakes Wilderness Area              0.09              0.06
                                              Lassen Volcanic National Park.
                                              Caribou Wilderness Area.......
BLIS1.......................................  Desolation Wilderness Area....              0.09              0.06
                                              Mokelumne Wilderness Area.....
PORE1.......................................  Point Reyes National Seashore.              0.16              0.14
YOSE1.......................................  Emigrant Wilderness Area......              0.12              0.08
                                              Yosemite National Park........
HOOV1.......................................  Hoover Wilderness Area........              0.07              0.03
KAIS1.......................................  Ansel Adams Wilderness Area...              0.11              0.06
                                              John Muir Wilderness Area.....
                                              Kaiser Wilderness Area........
PINN1.......................................  Pinnacles National Park.......          \a\ 0.11              0.13
                                              Ventana Wilderness Area.......
SEQU1.......................................  Kings Canyon National Park....              0.28              0.21
                                              Sequoia National Park.........
RAFA1.......................................  San Rafael Wilderness Area....              0.18              0.14
DOME1.......................................  Domeland Wilderness Area......              0.18              0.13
SAGA1.......................................  San Gabriel Wilderness Area...              0.20              0.17
                                              Cucamonga Wilderness Area.....
SAGO1.......................................  San Gorgonio Wilderness Area..              0.24              0.20
                                              San Jacinto Wilderness Area...
JOSH1.......................................  Joshua Tree National Park.....              0.19              0.15
AGTI1.......................................  Agua Tibia Wilderness Area....              0.23              0.18
----------------------------------------------------------------------------------------------------------------
Source: 2022 California Regional Haze Plan, Tables 8-3, 8-4, 8-5.

[[Page 103750]]

 
\a\ The unadjusted URP for the PINN1 IMPROVE monitor reported in the Plan appears to have been incorrectly
  transcribed from its source. The reported value of 0.11 dv/year should actually be 0.17 dv/year, based on the
  2004 and the 2024 natural conditions endpoint data reported in the WRAP TSS. This error does not affect other
  calculations or conclusions in the Plan.

    We propose to find that the 2022 California Regional Haze Plan 
meets the requirements of 40 CFR 51.308(f)(1) related to the 
calculations of baseline, current, and natural visibility conditions; 
progress to date; differences between current visibility conditions and 
natural visibility conditions, and the uniform rate of progress for 
each of its Class I areas for the second implementation period. We also 
propose to find that CARB has estimated the impacts from anthropogenic 
sources outside the United States and wildland prescribed fires using 
scientifically valid data and methods.

E. Long-Term Strategy for Regional Haze

    Each state having a Class I area within its borders or emissions 
that may affect visibility in a Class I area must develop a long-term 
strategy for making reasonable progress towards the national visibility 
goal.\131\ As explained in the Background section of this notice, 
reasonable progress is achieved when all states contributing to 
visibility impairment in a Class I area are implementing the measures 
determined--through application of the four statutory factors to 
sources of visibility impairing pollutants--to be necessary to make 
reasonable progress.\132\ Each state's long-term strategy must include 
the enforceable emission limitations, compliance schedules, and other 
measures that are necessary to make reasonable progress.\133\ All new 
(i.e., additional) measures that are the outcome of four-factor 
analyses are necessary to make reasonable progress and must be in the 
long-term strategy. If the outcome of a four-factor analysis and other 
measures necessary to make reasonable progress is that no new measures 
are reasonable for a source, that source's existing measures are 
necessary to make reasonable progress, unless the state can demonstrate 
that the source will continue to implement those measures and will not 
increase its emission rate. Existing measures that are necessary to 
make reasonable progress must also be in the long-term strategy. In 
developing its long-term strategies, a state must also consider the 
five additional factors in section 51.308(f)(2)(iv). As part of its 
reasonable progress determinations, the state must describe the 
criteria used to determine which sources or group of sources were 
evaluated (i.e., subjected to four-factor analysis) for the second 
implementation period and how the four factors were taken into 
consideration in selecting the emission reduction measures for 
inclusion in the long-term strategy.\134\
---------------------------------------------------------------------------

    \131\ CAA 169A(b)(2)(B).
    \132\ 40 CFR 51.308(f)(2)(i).
    \133\ 40 CFR 51.308(f)(2).
    \134\ 40 CFR 51.308(f)(2)(iii).
---------------------------------------------------------------------------

    The consultation requirements of section 51.308(f)(2)(ii) provide 
that states must consult with other states that are reasonably 
anticipated to contribute to visibility impairment in a Class I area to 
develop coordinated emission management strategies containing the 
emission reductions measures that are necessary to make reasonable 
progress. Section 51.308(f)(2)(ii)(A) and (B) require states to 
consider the emission reduction measures identified by other states as 
necessary for reasonable progress and to include agreed upon measures 
in their SIPs, respectively. Section 51.308(f)(2)(ii)(C) speaks to what 
happens if states cannot agree on what measures are necessary to make 
reasonable progress.
    Section 51.308(f)(2)(iii) requires that the emissions information 
considered to determine the measures that are necessary to make 
reasonable progress include information on emissions for the most 
recent year for which the state has submitted triennial emissions data 
to the EPA (or a more recent year), with a 12-month exemption period 
for newly submitted data.
    The following sections summarize how the 2022 California Regional 
Haze SIP addressed the requirements of section 51.308(f)(2) and the 
EPA's evaluation with respect to these requirements.
1. Determination of Which Pollutants To Consider
    To evaluate which pollutants had the largest impact at California's 
Class I areas, CARB considered light extinction budgets that showed the 
relative contribution from different pollutants measured during 2014-
2018 at IMPROVE monitors in the State. Overall (including both U.S. and 
non-U.S. sources) CARB found that, on the most impaired days, ammonium 
nitrate and ammonium sulfate comprised the largest portion of the light 
extinction budgets at sites near urban areas, while ammonium sulfate 
and organic mass formed the largest portion of light extinction budgets 
at sites further from urban areas.\135\ When looking only at U.S. 
anthropogenic sources, CARB concluded that ammonium nitrate was 
generally the dominant visibility reducing PM species, comprising an 
average of 49 percent of light extinction at Class I areas in 
California during 2014-2018.\136\ CARB also noted that, in prospective 
light extinction budgets developed for 2028, ammonium nitrate comprises 
an average of 38 percent of light extinction at Class I areas in 
California. Based on these considerations, CARB chose to focus its 
long-term strategy solely on NOX, which is considered the 
limiting precursor for ammonium nitrate.
---------------------------------------------------------------------------

    \135\ 2022 California Regional Haze Plan, pp. 69-70.
    \136\ Id. at 72.
---------------------------------------------------------------------------

    While we support CARB's focus on impacts from U.S. anthropogenic 
emissions, we find that its determination to focus its regional haze 
control strategy exclusively on NOX during this planning 
period is not adequately supported. The conclusion that NOX 
is the dominant visibility reducing PM species is not true for all of 
California's Class I areas, even when considering only U.S. 
anthropogenic sources. For example, prospective U.S. light extinction 
budgets for the most impaired days in 2028 indicate that at TRIN1 
(representing Marble Mountain Wilderness and Yolla Bolly-Middle Eel 
Wilderness Area), BLIS1 (representing Desolation Wilderness Area and 
Mokelumne Wilderness Area), and JOSH1 (representing Joshua Tree 
National Park), the contribution from U.S. anthropogenic sources from 
organic mass will exceed the contribution from ammonium nitrate on the 
most impaired days.\137\ And, even for the monitors where ammonium 
nitrate is projected to have the largest contribution in 2028, 
contributions from other species, such as organic matter and ammonium 
sulfate, may be significant as well. For example, in the prospective 
U.S. anthropogenic light extinction budgets for the most impaired days 
in 2028, the contribution from organic matter exceeds 20% of total 
impairment at nine monitors, and the contribution from ammonium sulfate 
exceeds 20% at one monitor.\138\
---------------------------------------------------------------------------

    \137\ 2022 California Regional Haze Plan, p. 73, Figure 5-5.
    \138\ Id.
---------------------------------------------------------------------------

    In addition, CARB has not adequately considered whether 
anthropogenic emissions of other pollutants from

[[Page 103751]]

California may contribute significantly to visibility impairment at 
out-of-state Class I areas.\139\ For example, ammonium sulfate 
constitutes a greater share of the total extinction budget than 
ammonium nitrate at all of the Class I areas in neighboring 
states.\140\ In addition, modeling results available from the WRAP TSS 
\141\ how that for ammonium sulfate from anthropogenic SO2 
emissions, California industrial point sources (nonEGUs) have the 
largest contribution to impairment of any state/source category 
combination for three Class I areas in other States: Zion, Bryce 
Canyon, and Grand Canyon National Parks. Further, the California nonEGU 
contribution is comparable to that from Arizona nonEGUs for the 
Mazatzal, Sierra Ancha, and Sycamore Wilderness Areas in Arizona, and 
comparable to the EGU contribution at Capitol Reef National Park.
---------------------------------------------------------------------------

    \139\ See 40 CFR 51.308(f)(2).
    \140\ 2022 California Regional Haze Plan, pp. 65-67.
    \141\ WRAP Technical Support System, Modeling Express Tools, 
``WRAP State Source Group Contributions--U.S. Anthro'', http://views.cira.colostate.edu/tssv2/Express/ModelingTools.aspx.
---------------------------------------------------------------------------

    For these reasons, it is not clear that ammonium nitrate is the 
dominant species resulting from U.S. anthropogenic emissions at all 
Class I areas affected by emissions from California and therefore, we 
determine that it was unreasonable for CARB not to conduct any 
evaluation of potential controls for the other pollutants.
2. Source Selection
    In the Plan, CARB states that its source selection goal for this 
regional haze plan was to consider sources that accounted for at least 
50 percent of the NOX emissions in the inventory, 
considering both 2014 and 2017 emissions inventories. Noting the 
significant role of mobile source emissions in California and the 
State's authority to establish emissions standards for certain mobile 
sources, CARB chose to focus its source-selection process on mobile 
sources, but also considered stationary sources.
a. Mobile Sources
    CARB provided a summary of 2017 and projected 2028 NOX 
emissions in tons per day (tpd) from various mobile source sectors in 
table 5-1 of the Plan, which is reproduced as table 4 of this document. 
Based on these data, CARB selected light and medium-duty vehicles, 
heavy-duty trucks, off-road equipment, trains, and ocean-going vessels 
for four-factor analysis, explaining that emissions from these five 
source groups account for 60 percent of NOX emissions in the 
2017 inventory and are projected to account for 50 percent of 
NOX emissions in 2028.\142\ CARB also noted that it did not 
select aircraft for analysis because Federal action would be needed to 
address this source category.
---------------------------------------------------------------------------

    \142\ Id. at 75-76.

              Table 4--CARB Mobile Source Sector Emissions
------------------------------------------------------------------------
                                       2017 Emissions    Projected 2028
         Sector description                 (tpd)        emissions (tpd)
------------------------------------------------------------------------
On-Road: Heavy-Duty Trucks..........               409               227
On-Road: Light & Medium-Duty Trucks.               111                31
On-Road: Light-Duty Passenger.......                70                26
On-Road: Other (Buses, Motorcycles,                 29                18
 Motorhomes)........................
Off-Road: Off-Road Equipment........               222               132
Off-Road: Trains....................                78                37
Off-Road: Aircraft..................                46                59
Off-Road: Ocean-Going Vessels.......                28                37
Off-Road: Commercial Harbor Craft...                19                18
Off-Road: Recreational Boats........                16                13
Off-Road: Recreational Vehicles.....                 1                 1
------------------------------------------------------------------------

    With respect to NOX emissions from mobile sources 
specifically, we find that CARB selected a reasonable set of source 
categories for four-factor analysis. However, as discussed in section 
IV.E.3.a of this document, we find that CARB did not adequately analyze 
and consider the four factors in relation to these source categories.
b. Stationary Sources
    CARB conducted a four-step process to select sources for four-
factor analysis:
     Step 1: Calculate NOX emissions (Q) in tons 
divided by distance (d) in km (Q/d) and screen in facilities with a 
NOX Q/d greater than five for further consideration.
     Step 2: Review device level emissions inventories and 
screen out sources if actual emissions or emissions under State or 
local jurisdiction resulted in a Q/d less than five.
     Step 3: Review existing controls, planned controls, and 
proposed operational changes. Screen out sources if this information 
indicated that a full four factor analysis would likely result in the 
conclusion that reasonable controls are in place.
     Step 4: Proceed with consideration and evaluation of four 
statutory factors.
    We evaluate steps 1-3 of CARB's analysis in this section and step 4 
in section IV.E.3.b of this document.
    In step 1 of its stationary source screening process, CARB 
calculated NOX-only Q/d values using 2017 NEI NOX 
emissions data and the distance between a stationary source and Class I 
areas and selected the sources with a Q/d value greater than 5. The 
results of this analysis are summarized in table G-1 of the Plan, which 
is reproduced as Table 5 of this document.

                                 Table 5--Stationary Sources Selected at Step 1
----------------------------------------------------------------------------------------------------------------
                                                                             Distance     2017 NEI
               Facility name                  Location with maximum Q/d        (km)        (tpy)         Q/d
----------------------------------------------------------------------------------------------------------------
Chevron Products Company..................  Point Reyes National Seashore           28          737         26.4
Lehigh Southwest Cement Company...........  Point Reyes National Seashore           86         1208         14.0
Oakland Metropolitan International Airport  Point Reyes National Seashore           50         1262         25.4

[[Page 103752]]

 
Phillips 66 Carbon Plant..................  Point Reyes National Seashore           43          360          8.5
Phillips 66 Company--San Francisco          Point Reyes National Seashore           43          218          5.1
 Refinery.
San Francisco International Airport.......  Point Reyes National Seashore           45         5105        113.4
San Jose Airport--Norman Y Mineta.........  Point Reyes National Seashore           92          884          9.6
Shell Martinez Refinery (now owned by PBF)  Point Reyes National Seashore           53          916         17.2
Tesoro Refining & Marketing Company Llc...  Point Reyes National Seashore           57          360          6.3
Valero Refining Company...................  Point Reyes National Seashore           52         1013         19.3
CalPortland Cement--Mojave Plant..........  Domeland Wilderness Area.....           75         1531         20.5
Granite Construction--Lee Vining..........  Ansel Adams Wilderness Area..            6           31          5.2
Kirkwood Powerhouse.......................  Mokelumne Wilderness Area....            1           10         16.6
Cal Portland Oro Grande (formerly           Cucamonga Wilderness Area....           41         1141         27.9
 Riverside).
Cemex--Black Mountain Quarry..............  San Gorgonio Wilderness Area.           53         5420        101.6
Mitsubishi Cement.........................  San Gorgonio Wilderness Area.           33         1944         59.7
Searles Valley Mineral....................  Domeland Wilderness Area.....           71         1517         21.3
Arcata....................................  Redwood National Park........           17          163          9.7
Collins Pine Co...........................  Caribou Wilderness Area......           12          129         10.4
Sierra Pacific Industries--Quincy.........  Caribou Wilderness Area......           59          392          6.6
Sacramento International Airport..........  Desolation Wilderness Area...          117          737          6.3
San Diego International-Lindberg..........  Agua Tibia Wilderness Area...           74         1580         21.3
Burney Forest Products....................  Thousand Lakes Wilderness               17          190         11.2
                                             Area.
Lehigh Southwest Cement Company...........  Thousand Lakes Wilderness               56          603         10.7
                                             Area.
Sierra Pacific Industries--Burney.........  Thousand Lakes Wilderness               18          157          8.9
                                             Area.
Wheelabrator Shasta E.C.I.................  Yolla Bolly-Middle Eel                  57          536          9.4
                                             Wilderness Area.
Bob Hope Airport..........................  San Gabriel Wilderness Area..           31          375         12.0
California Steel Industries Inc...........  Cucamonga Wilderness Area....           16          125          7.8
Chevron Products Co.......................  San Gabriel Wilderness Area..           52          729         14.0
Desert View Power.........................  Joshua Tree National Park....           24          189          7.8
John Wayne Airport........................  Cucamonga Wilderness Area....           62          698         11.3
Long Beach Daugherty Field Airport........  San Gabriel Wilderness Area..           49          308          6.3
Los Angeles International Airport.........  San Gabriel Wilderness Area..           49         7836        159.0
New-Indy Ontario, Llc.....................  Cucamonga Wilderness Area....           18          137          7.5
Ontario International Airport.............  Cucamonga Wilderness Area....           17          679         40.2
Palm Springs International Airport........  San Jacinto Wilderness Area..           10          159         16.4
Phillips 66 Co/La Refinery Wilmington Pl..  San Gabriel Wilderness Area..           58          471          8.1
Phillips 66 Company/Los Angeles Refinery..  San Gabriel Wilderness Area..           53          391          7.3
Tamco.....................................  Cucamonga Wilderness Area....           13          108          8.3
Tesoro Refining & Marketing (Carson)......  San Gabriel Wilderness Area..           51          661         13.0
Tesoro Refining and Marketing (Wilmington)  San Gabriel Wilderness Area..           54          749         13.8
Torrance Refining (formerly Exxon Mobil)..  San Gabriel Wilderness Area..           52          924         17.6
----------------------------------------------------------------------------------------------------------------

    With respect to NOX emissions from point sources 
specifically, we find that CARB's use of a Q/d threshold of 5 resulted 
in the selection of a reasonable set of sources. However, the Plan only 
included the emissions data and distance values for the sources that 
were selected. Therefore, it was not possible for the EPA or the public 
to verify the emissions and distance values for sources that were not 
selected.
    In Step 2 of its Stationary Source Screening process, CARB screened 
out 17 sources based on a ``device-level inventory,'' where ``actual 
emissions or emissions under State or local jurisdiction led to a Q/d 
less than five.'' \143\ The sources screened out at this stage are 
summarized in table 6 of this document.
---------------------------------------------------------------------------

    \143\ Id. appendix G, p. 154.

           Table 6--Stationary Sources Screened Out at Step 2
------------------------------------------------------------------------
        Facility name                 Rationale for screening out
------------------------------------------------------------------------
Oakland Metropolitan           Vast majority of emissions are from
 International Airport.         aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
San Francisco International    Vast majority of emissions are from
 Airport.                       aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
San Jose Airport--Norman Y     Vast majority of emissions are from
 Mineta.                        aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
Tesoro Refining & Marketing    The refinery has been idled since 2020
 Company Llc.                   and owner is proposing to convert the
                                refinery to a renewable fuels facility.
Granite Construction--Lee      Per district staff, actual NOX emissions
 Vining.                        from this source in 2017 were 0.5 tpy
                                and were consistent with emissions from
                                a typical operating year.
Kirkwood Powerhouse..........  In 2014, Kirkwood Meadows Public
                                Utilities District transitioned to line
                                power and all the generators were
                                transitioned from prime to emergency
                                back-up engines. Actual NOX emissions
                                since 2014 have been less than 0.1 tpy.

[[Page 103753]]

 
Arcata.......................  Vast majority of emissions are from
                                aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
Sacramento International       Vast majority of emissions are from
 Airport.                       aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
San Diego International-       Vast majority of emissions are from
 Lindberg.                      aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
Bob Hope Airport.............  Vast majority of emissions are from
                                aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
Desert View Power............  Facility is located on Cabazon Indian
                                Reservation land.
John Wayne Airport...........  Vast majority of emissions are from
                                aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits
Long Beach Daugherty Field     Vast majority of emissions are from
 Airport.                       aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
Los Angeles International      Vast majority of emissions are from
 Airport.                       aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
Ontario International Airport  Vast majority of emissions are from
                                aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
Palm Springs International     Vast majority of emissions are from
 Airport.                       aircraft, for which state and local
                                agencies do not have authority to set
                                emissions limits.
Tamco........................  Facility was permanently shut down in
                                January 2021.
------------------------------------------------------------------------

    As with step 1, we find that CARB's determinations at step 2 were 
not adequately documented. In particular, CARB did not include in the 
Plan the device-level emissions inventory that it used to screen out 
sources. Thus, while we find that it was reasonable for the State to 
focus on emissions under State and/or local jurisdiction and to 
therefore screen out 12 airports and one source on tribal land, for the 
other screened-out sources, additional documentation is needed to 
verify the basis upon which the sources were screened out.\144\
---------------------------------------------------------------------------

    \144\ See 40 CFR 51.308(f)(2)(iii); Clarifications Memo, p. 5.
---------------------------------------------------------------------------

    In Step 3 of its screening process, CARB screened out 24 stationary 
sources based on its determination that ``information about existing 
controls, planned controls, or planned operational changes indicated 
that a full four factor analysis would likely result in the conclusion 
that, for the purposes of the regional haze program, reasonable 
controls are in place and no further reasonable controls are necessary 
at this time.'' \145\ The controls or measures cited by CARB in making 
this determination for the 24 sources include existing or anticipated 
controls required by currently applicable district rules, expected 
district rules, permit requirements, and/or consent decrees. The 
sources screened out at this step are shown in table 7.
---------------------------------------------------------------------------

    \145\ Id. at 154.

           Table 7--Stationary Sources Screened Out at Step 3
------------------------------------------------------------------------
        Facility name                 Rationale for screening out
------------------------------------------------------------------------
Chevron Products Company.....  Multiple furnaces have selective
                                catalytic reduction (SCR) units and
                                permit limits of 40 ppm NOX at 3% O2 (8-
                                hour average). Cogeneration turbines
                                have SCR units and emission limits of
                                <10 ppm at 15% O2 (3-hour average) and
                                0.20 lb NOX per million British thermal
                                units (MMBtu) as a 30-day rolling
                                average. Facility's operating permit
                                includes the federal interim refinery-
                                wide emissions limit (excluding CO
                                boilers) of 0.20 lb NOX/MMBtu as well as
                                the more stringent refinery-wide
                                emissions limit (excluding CO boilers)
                                of 0.033 lb NOX/MMBtu.
Lehigh Southwest Cement        Emission limit of 2.0 lb NOX/ton of
 Company.                       clinker under federal consent decree.
Phillips 66 Carbon Plant.....  Planned decommissioning of the plant.
Phillips 66 San Francisco      Planned conversion to facility that would
 Refinery.                      process renewable feedstocks.
Shell Martinez Refinery......  Turbine boiler is equipped with an SCR
                                system and has NOX emissions limits of
                                less than or equal to 5 ppmv NOX at 15%
                                O2. A 2001 EPA consent decree required
                                optimization of NOX emissions controls
                                for other boilers. Boilers are also
                                subject to Bay Area Air Quality
                                Management District (BAAQMD) Regulation
                                9, Rule 10 which has been determined to
                                meet Best Available Retrofit Control
                                Technology (BARCT) stringency.
Valero Refining Company......  NOX emissions are controlled through SCR
                                systems and low NOX burners. BAAQMD
                                Regulation 9, Rule 10 applies to heaters
                                and boilers (except for CO boilers) at
                                refineries and sets the refinery-wide
                                NOX emissions limit at 0.033 lb NOX/
                                MMBtu of heat input (daily average) and
                                facility-wide federal limit of 0.20 lb
                                NOX/MMBtu of heat input.
Cal Portland Mojave Plant....  EPA consent decree required installation
                                of selective non-catalytic reduction
                                (SNCR) and established an emissions
                                limit of 2.5 lb NOX/ton of clinker for
                                kiln. Eastern Kern APCD Rule 425.3 found
                                to be meet BARCT stringency.
Cemex--Black Mountain Quarry.  Federal consent decree established a NOX
                                emission limit of 1.95 lb/ton of
                                clinker. The kilns are also subject to
                                Mojave Desert AQMD Rule 1161--Portland
                                Cement Kilns, which was revised in 2018
                                to meet federal RACT stringency and
                                California BARCT stringency.
Mitsubishi Cement              The NOX emissions limit for cement kiln
 (Cushenberry Plant).           in the Title V permit is 2.8 lb/ton of
                                clinker.
Cal Portland Oro Grande......  The NOX emissions limit for cement kiln
                                is 2.45 lb/ton of clinker.

[[Page 103754]]

 
Searles Valley Mineral.......  The smallest boiler complies with a best
                                available control technology (BACT)
                                emissions limit of 9 ppmv. All the
                                boilers are subject to Rule 1157.1,
                                which was adopted in 2019 to meet the AB
                                617 expedited BARCT requirements.
Sierra Pacific Industries--    NOX emissions are controlled by ammonia
 Quincy.                        injection.
Burney Forest Products.......  The boilers are equipped with an SNCR
                                unit with anhydrous ammonia injection
                                for NOX control. Title V permit includes
                                BACT emissions limits for NOX.
Lehigh Southwest Cement        EPA Consent Decree limits NOX emissions
 Company.                       to 1.95 lb/ton clinker with combustion
                                controls or SNCR.
Sierra Pacific Industries--    NOX emissions are controlled through
 Burney.                        ammonia injection, staged combustion
                                controls, flue gas recirculation, and
                                low NOX burners when combusting natural
                                gas at start-up/shutdown.
Wheelabrator Shasta E.C.I....  NOX emissions are controlled through
                                ammonia injection, staged combustion
                                controls, flue gas recirculation, and
                                low NOX burners when combusting natural
                                gas at start-up/shutdown.
California Steel Industries..  By January 2022, the facility is planning
                                to replace two existing 33 MMBtu/hr
                                boilers with two new 32.54 MMBtu/hr
                                boilers to comply with a 5 ppm NOX limit
                                in South Coast AQMD Rule 1146.
Chevron Products Co..........  NOX control equipment includes low NOx
                                burners in heaters/boilers, SCR units,
                                and NOX reducing catalyst in the fluid
                                catalytic cracking unit (FCCU).
                                Recently, the facility replaced five
                                heater burners with low NOX burners and
                                the district recently received a
                                proposal from the facility to install
                                SCR on two large heaters. South Coast
                                AQMD Rule 1109.1 is being developed for
                                all NOX emitting sources at the
                                refineries.
New Indy Ontario LLC.........  New combined heat and power units placed
                                in operation in the fall of 2019 with
                                BACT limit of 2 ppm NOX at 15% O2.
                                Boiler required to meet a 5 ppm NOX and
                                5 ppm NH3 at 3% O2 under South Coast
                                AQMD Rule 1146.
Phillips 66 Co/Los Angeles     In the last six years, equipment changes
 Refinery--Carson.              have included the installation of an SCR
                                unit on boiler 11 and the reformer
                                heater. South Coast AQMD Rule 1109.1 is
                                being developed for all NOX emitting
                                sources at the refineries.
Phillips 66 Co/LA Refinery     SCR was recently installed on the FCCU.
 Wilmington.                    Boilers and heaters are equipped with
                                low NOX burners. South Coast AQMD Rule
                                1109.1 is being developed for all NOX
                                emitting sources at the refineries.
Tesoro Refining and Marketing  FCCU shutdown at Wilmington completed in
 Co.--Carson and Wilmington.    October 2018. South Coast AQMD Rule
                                1109.1 is being developed for all NOX
                                emitting sources at the refineries.
Torrance Refining (formerly    NOX control equipment at the refinery
 ExxonMobil).                   includes low NOX burners in heaters/
                                boilers, SCR units, and NOX reducing
                                catalyst in the FCCU. South Coast AQMD
                                Rule 1109.1 is being developed for all
                                NOX emitting sources at the refineries.
------------------------------------------------------------------------

    We find that step 3 of CARB's source selection process was flawed 
in several respects. First, as with steps 1 and 2, step 3 of CARB's 
source selection process was inadequately documented. In particular, 
the Plan did not include unit-specific emissions and control 
information for all of the sources that were screened out. In response 
to a request from NPS, CARB did post a device-level emissions inventory 
on its website.\146\ However, this inventory provided only total annual 
2017 NOX emissions and did not include information about existing 
controls or emissions limitations. Without this information, it is not 
possible to evaluate whether all the units with significant NOX 
emissions are effectively controlled. Moreover, the device-level 
inventory was not included in the SIP submittal.
---------------------------------------------------------------------------

    \146\ https://ww2.arb.ca.gov/our-work/programs/california-state-implementation-plans/statewide-efforts/regional-haze.
---------------------------------------------------------------------------

    Second, for those units where emissions limits were provided, CARB 
did not adequately explain why it was reasonable to assume, without 
conducting a four-factor analysis, that no additional controls or more 
stringent emissions limitations would be reasonable. In particular, for 
most of the screened-out sources, CARB cited existing or expected 
determinations of best available retrofit control technology (BARCT) 
under California state law and/or determinations of reasonably 
available control technology (RACT) for purposes of Federal ozone 
requirements and/or determinations as part of the basis for screening 
sources out. However, while the 2019 Guidance lists more stringent 
controls requirements, such as BACT and lowest achievable emissions 
rate (LAER) determinations issued since 2013, as examples of effective 
controls,\147\ it does not list RACT determinations as examples an 
effective control. RACT is a less stringent requirement than either 
BACT or LAER.\148\ In addition, some elements of BARCT and RACT 
analyses differ from Regional Haze four-factor analyses and different 
cost effectiveness thresholds may apply for purposes of BARCT and RACT 
as compared with regional haze. For example, Eastern Kern APCD Rule 
425.3 and Mojave Desert AQMD Rule 1161 establish NOX 
emissions limits for RACT and BARCT that correspond to the use of 
combustion controls, which are generally less stringent than post-
combustion controls, such as SNCR. The Staff Reports for these two 
rules indicate that the cost effectiveness of more stringent limits, 
such as limits corresponding to the use of SNCR, would range from 
approximately $1,700/ton to $4,100/ton of NOX removed.\149\ 
These $/ton figures are within the range of what has been considered 
cost-effective for regional haze reasonable progress measures by many 
western states, including California's neighboring states of

[[Page 103755]]

Arizona,\150\ Nevada,\151\ and Oregon.\152\ Accordingly, it was not 
reasonable for CARB to assume that RACT and/or BARCT controls 
necessarily constitute effective controls for purposes of regional haze 
in all cases.
---------------------------------------------------------------------------

    \147\ 2019 Guidance, p. 23.
    \148\ See, e.g., Memorandum dated May 18, 2006 from William T. 
Harnett Director, Air Quality Policy Division, EPA, to Regional Air 
Division Directors, Subject: ``Questions Related to RACT in 8-hour 
ozone implementation,'' answer A.1 (``BACT requires that new or 
modified sources adopt the best available controls and, as such, the 
analysis is a `top-down' analysis that first looks at the most 
stringent level of control available for a source. . . . RACT 
requires that sources adopt controls that are reasonably available 
and thus they may not be the most stringent controls that have been 
adopted for other similar sources.'')
    \149\ Eastern Kern APCD, ``Final Staff Report, Rule 425.3,'' 
March 8, 2018, p. D-2; Mojave Desert AQMD ``Staff Report, Amendments 
to Rule 1161'', January 22, 2018, appendix F.
    \150\ 89 FR 47398, 47415 (May 31, 2024).
    \151\ Nevada Division of Environmental Protection, Nevada 
Regional Haze State Implementation Plan for the Second Planning 
Period at 5-6 (August 2022), available at https://ndep.nv.gov/uploads/air-plan_mod-docs/All_SIP_Chapters.pdf (``NDEP is relying on 
a cost-effectiveness ($/ton reduced) threshold of $10,000.'')
    \152\ 89 FR 13622, 13638 (February 23, 2024).
---------------------------------------------------------------------------

    Instead, under these circumstances, CARB should have evaluated such 
controls on a case-by-case basis to determine whether it is reasonable 
to assume that a full four-factor analysis would likely result in the 
conclusion that no further controls are necessary.\153\ CARB did not do 
so in the Plan. For example, for the Mitsubishi Cement Cushenbury 
Plant, the Cal Portland Mojave Plant, and the Cal Portland Oro Grande 
Cement Plant, CARB cited NOX emissions limits of 2.8 lb/ton 
of clinker, 2.5 lb/ton of clinker, and 2.45 lb/ton of clinker, 
respectively.\154\ These limits are significantly higher than the 
applicable limits at other cement kilns, such as National Cement Lebec 
Unit 042, which has a limit of 1.5 lb/ton of clinker (30-day) in its 
Title V Permit.\155\ The Mitsubishi Cement kiln does not have SNCR 
installed.\156\ Given that many other cement kilns have installed SNCR 
as a retrofit NOX control,\157\ we find that CARB did not 
adequately justify why a four-factor analysis would likely result in a 
determination that an emissions limit corresponding to SNCR is not 
necessary to make reasonable progress at this unit. The two kilns at 
Cal Portland Oro Grande Cement Plant have SNCR installed for ``optional 
use,'' \158\ and the kiln at the Cal Portland Mojave Plant has SNCR 
installed under a Consent Decree.\159\ However, other cement kilns in 
California with SNCR are subject to significantly more stringent 
NOX emissions limits than the limits at these three 
kilns.\160\ Accordingly, we find that CARB did not adequately justify 
why four-factor analyses would likely result in a determination that no 
more stringent limits are necessary to make reasonable progress at 
these units. Similar considerations apply to other units that CARB 
screened out because they had installed controls constituting RACT and/
or BARCT. Therefore, we find it was not reasonable for CARB to screen 
out units merely because they had installed controls constituting RACT 
and/or BARCT without further consideration of the stringency of these 
controls on a unit-specific basis.
---------------------------------------------------------------------------

    \153\ 2019 Guidance pp. 22-23.
    \154\ Averaging times for these emissions limits were not 
provided.
    \155\ Permit 1128-V-2000 (Issued on 5/1/2024); Operational 
Condition 14.
    \156\ Permit 11800001 (Issued on 6/18/20), Condition II.A.33.
    \157\ See, e.g., EPA, Control Cost Manual, section 4, Chapter 1, 
Selective Noncatalytic Reduction, p. 1-5 (``SNCR was designated as 
BART for 11 cement kilns'').
    \158\ Permit 223900003 (Issued on 1/8/2021); (Significant Permit 
Modification on 6/23/2021).
    \159\ United States of America. v. CalPortland Company, E.D. 
Cal. Case 1:11-at-00790, Document 2-1, filed 12/15/11.
    \160\ See table 7 of this document.
---------------------------------------------------------------------------

    Third, in some instances, CARB relied on rules that had not yet 
been adopted at the time of its analysis. For example, for the 
refineries in South Coast, CARB stated that ``Rule 1109.1 is being 
developed for all NOX emitting sources at the refineries.'' 
\161\ We find it was not reasonable for CARB to screen out sources 
based on the expected future applicability of rules that have not yet 
been adopted.
---------------------------------------------------------------------------

    \161\ Plan appendix G, p. 180.
---------------------------------------------------------------------------

    Finally, for each source that was screened out based on existing 
effective measures, CARB should have determined whether those measures 
are necessary for reasonable progress. As noted in section III.C of 
this document and further explained in the Clarifications Memo, 
generally a source/category's existing measures are needed to prevent 
future emissions increases and are thus needed to make reasonable 
progress.\162\ If CARB concludes that the existing controls at a 
particular source are necessary to make reasonable progress, CARB must 
adopt emissions limits based on those controls as part of its long-term 
strategy for the second planning period and include those limits in its 
SIP (to the extent they do not already exist in the SIP).\163\ 
Alternatively, if CARB can demonstrate that the source/category will 
continue to implement its existing measures and will not increase its 
emissions rate, it may be reasonable for the State to conclude that the 
existing controls are not necessary to make reasonable progress. In 
this instance, the emissions limits may not need to be adopted into the 
long-term strategy and SIP.\164\
---------------------------------------------------------------------------

    \162\ Clarifications Memo, pp. 8-10.
    \163\ CAA 169A(b)(2); 40 CFR 51.308(f)(2).
    \164\ 2019 Guidance p.43; Clarifications Memo, pp.8-9.
---------------------------------------------------------------------------

    In sum, due to a lack of documentation for steps 1-3 and inadequate 
justification for its determinations under step 3, we find that CARB's 
source selection process for stationary sources did not adequately 
address the requirement of 40 CFR 51.308(f)(2)(i) to provide a 
description of the criteria used to select sources, or the requirement 
of 40 CFR 51.308(f)(2)(iii) to provide documentation of the technical 
basis used to determine emission reduction measures.
3. Four-Factor Analyses and Control Determinations
a. Mobile Sources
    For each of the selected mobile source categories, CARB discussed 
control measures that had been identified in previous state plans and 
provided information related to the four reasonable progress factors in 
order ``to highlight the consideration of the four reasonable progress 
factors embodied in CARB's rule making process.'' \165\ CARB stated 
that, based on this information, it identified four control options as 
necessary to make reasonable progress: the Heavy-Duty Omnibus 
Regulation, the Heavy-Duty I/M Program Regulation, the Advanced Clean 
Trucks Regulation, and the Advanced Clean Cars II Regulation.\166\
---------------------------------------------------------------------------

    \165\ Plan, appendix H, p. 185. See also Plan pp. 83-105 and 
appendix H.
    \166\ Id. at 109.
---------------------------------------------------------------------------

    We commend CARB's ambitious on-going program of mobile source 
emissions control measures, which has been developed to meet 
California's air quality, climate, and community health goals.\167\ 
However, we find that, while CARB presented information about the four 
factors in relation to on-the-books/on-the-way mobile source 
requirements, CARB did not describe if or how it weighed the statutory 
factors to determine which controls are necessary for reasonable 
progress. For example, while most states have primarily considered the 
cost effectiveness of controls in determining which controls are 
necessary to make reasonable progress, CARB did not provide cost-
effectiveness values for most of the control measures it 
considered,\168\ nor did it indicate what level of cost effectiveness 
it considers to be reasonable. In the absence of such analysis and 
explanation, we propose find that CARB's consideration of mobile source 
control measures does

[[Page 103756]]

not meet the requirement of 40 CFR 52.308(2)(f)(i) to include a 
description of ``how the four factors were taken into consideration in 
selecting the measures for inclusion'' in the LTS or the requirement of 
40 CFR 52.308(2)(f)(iii) to provide documentation of the technical 
basis used to determine emission reduction measures.
---------------------------------------------------------------------------

    \167\ See, e.g., id. at 82 (``Integrated planning efforts 
focused on reducing emissions and improving air quality to meet 
California's air quality, climate, and community health goals will 
yield meaningful progress in reducing visibility impairing PM.'')
    \168\ For the Heavy-Duty Omnibus Regulation, CARB estimated a 
total cost effectiveness of $38,788/ton of NOX in 2022-
2032, and for the Heavy-Duty I/M program, CARB estimated the cost-
effectiveness to be $31,677/ton of NOX in 2024, $5,209/
ton of NOX in 2031, and $4,428/ton of NOX in 
2037. CARB did not provide cost-effectiveness values for the other 
measures.
---------------------------------------------------------------------------

b. Stationary Sources
    CARB provided a four-factor analysis for a single unit: a Keeler 
Cogeneration Boiler at the Collins Pine Company wood products and 
cogeneration facility in Chester. As part of this analysis, CARB 
considered several potential control options, but concluded that the 
only technically feasible options were (1) good combustion practices, 
which are already in effect, and (2) SNCR. After evaluating the four 
factors for the SNCR option, CARB determined that retrofit of the 
existing boiler system with an SNCR system was not reasonable because 
``[t]he existing boiler configuration does not provide for adequate 
residence time without injection of excess reagent, which is likely to 
lead to high levels of ammonia slip.'' \169\
---------------------------------------------------------------------------

    \169\ Plan, p. 108.
---------------------------------------------------------------------------

    CARB found that the use of good combustion practices is necessary 
to ensure control of NOX emissions from the boiler at 
Collins Pine. CARB stated that good combustion practices are already in 
place at the facility and are enforceable as they are a condition of 
the facility's Title V operating permit. However, CARB did not provide 
a demonstration that use of good combustion practices was not necessary 
to make reasonable progress. Therefore, as explained in section III.C 
of this document, CARB should have submitted this measure for SIP 
approval.
4. Conclusions
    For the reasons described in the preceding sections, we propose to 
find that CARB failed to reasonably ``evaluate and determine the 
emission reduction measures that are necessary to make reasonable 
progress'' by considering the four statutory factors as required by 40 
CFR 51.308(f)(2)(i) and CAA section 169A(g)(1). We also propose to find 
that CARB failed to adequately document the technical basis that it 
relied upon to determine these emissions reduction measures, as 
required by 40 CFR 51.308(f)(2)(iii).
    In addition, 51.308(f)(2) requires the long-term strategy to 
``include the enforceable emissions limitations, compliance schedules, 
and other measures that are necessary to make reasonable progress, as 
determined pursuant to (f)(2)(i) through (iv).'' As described in the 
preceding sections, with the exception of the four mobile-source 
measures that CARB deemed to be necessary for reasonable progress, CARB 
did not clearly identify which measures it has determined were 
necessary to make reasonable progress. Accordingly, CARB failed to 
submit to the EPA a long-term strategy that includes ``the enforceable 
emissions limitations, compliance schedules, and other measures that 
are necessary to make reasonable progress'' as required by 40 CFR 
51.308(f)(2).\170\
---------------------------------------------------------------------------

    \170\ See also CAA 169A(b)(2), 169(b)(2)(B) (the CAA requires 
that each implementation plan for a State in which the emissions 
from may reasonably be anticipated to cause or contribute to 
visibility impairment in a Class I area ``contain such emission 
limits, schedules of compliance and other measures as may be 
necessary to make reasonable progress toward meeting the national 
goal, . . . including . . . a long-term . . . strategy for making 
reasonable progress[.]''
---------------------------------------------------------------------------

    Consequently, the EPA proposes to find that the 2022 California 
Regional Haze Plan does not satisfy the requirements of 40 CFR 
51.308(f)(2).

F. Reasonable Progress Goals

    Section 51.308(f)(3) contains the requirements pertaining to RPGs 
for each Class I area. Because California is host to multiple Class I 
areas, it is subject to both section 51.308(f)(3)(i) and, potentially, 
to (ii). Section 51.308(f)(3)(i) requires a state in which a Class I 
area is located to establish RPGs--one each for the most impaired and 
clearest days for each Class I area--reflecting the visibility 
conditions that will be achieved at the end of the implementation 
period as a result of the emissions limitations, compliance schedules, 
and other measures required under paragraph (f)(2) to be in states' 
long-term strategies, as well as implementation of other CAA 
requirements. The long-term strategies as reflected by the RPGs must 
provide for an improvement in visibility on the most impaired days 
relative to the baseline period and ensure no degradation on the 
clearest days relative to the baseline period. Section 51.308(f)(3)(ii) 
applies in circumstances in which a Class I area's RPG for the most 
impaired days represents a slower rate of visibility improvement than 
the URP calculated under 40 CFR 51.308(f)(1)(vi). Under section 
51.308(f)(3)(ii)(A), if the state in which a mandatory Class I area is 
located establishes an RPG for the most impaired days that provides for 
a slower rate of visibility improvement than the URP, the state must 
demonstrate that there are no additional emissions reduction measures 
for anthropogenic sources or groups of sources in the state that would 
be reasonable to include in its long-term strategy. Section 
51.308(f)(3)(ii)(B) requires that if a state contains sources that are 
reasonably anticipated to contribute to visibility impairment in a 
Class I area in another state, and the RPG for the most impaired days 
in that Class I area is above the URP, the upwind state must provide 
the same demonstration.
    CARB's RPGs are set out in table 8-1 of the Plan, which is 
reproduced as table 8 of this document. In the Plan, CARB explains that 
the RPGs for the most impaired days are based on the emissions inputs 
that include implementation of control programs adopted at the time of 
the emissions inventory development and the additional aggregate 
emissions reduction commitment proposed in CARB's long-term 
strategy,\171\ while the RPGs for the clearest days are equal to 
average visibility conditions on the clearest days during the 2000-2004 
baseline period.
---------------------------------------------------------------------------

    \171\ The last column of Plan table 7-5, p.131 is headed ``2028 
Visibility Projections (dv) with Potential Additional Controls (PAC2 
Emissions).'' While it is not explicitly stated in the Plan, that 
was the WRAP model scenario mainly relied upon in the Plan. Unless 
otherwise indicated, all of the Plan's 2028 projections and RPGs are 
identical to results from WRAP modeling scenario PAC2_EPAwoF ``PAC2 
EPA w/o Fire Projection,'' available in WRAP TSS modeling tools 4 
and 5. The PAC2 scenario reflected ``Potential Additional 
Controls,'' including California mobile source control measures; the 
``woF'' means ``without fire'' in the calculation of Relative 
Response Factors to apply to monitored or other modeled 
concentrations.

[[Page 103757]]



                    Table 8--Baseline Conditions and RPGs for Clearest and Most Impaired Days
----------------------------------------------------------------------------------------------------------------
                                                                                             Most        Most
                                                                   Clearest    Clearest    impaired    impaired
             IMPROVE site                     Class I area         baseline    2028 RPG    baseline    2028 RPG
                                                                     (dv)        (dv)        (dv)        (dv)
----------------------------------------------------------------------------------------------------------------
LABE1.................................  Lava Beds National               3.2         3.2        11.3         8.9
                                         Monument.
                                        South Warner Wilderness
                                         Area.
REDW1.................................  Redwood National Park...         6.1         6.1        13.7        11.9
TRIN1.................................  Marble Mountain                  3.4         3.4        11.9         9.5
                                         Wilderness Area.
                                        Yolla Bolly-Middle Eel
                                         Wilderness Area.
LAVO1.................................  Thousand Lakes                   2.7         2.7        11.5         9.4
                                         Wilderness Area.
                                        Lassen Volcanic National
                                         Park.
                                        Caribou Wilderness Area.
BLIS1.................................  Desolation Wilderness            2.5         2.5        10.1         8.3
                                         Area.
                                        Mokelumne Wilderness
                                         Area.
PORE1.................................  Point Reyes National            10.5        10.5        19.4        14.4
                                         Seashore.
YOSE1.................................  Emigrant Wilderness Area         3.4         3.4        13.5        10.4
                                        Yosemite National Park..
HOOV1.................................  Hoover Wilderness Area..         1.4         1.4         8.9         7.1
KAIS1.................................  Ansel Adams Wilderness           2.3         2.3        12.9         9.8
                                         Area.
                                        John Muir Wilderness
                                         Area.
                                        Kaiser Wilderness Area..
PINN1.................................  Pinnacles National Park.         8.9         8.9        17.0        13.0
                                        Ventana Wilderness Area.
SEQU1.................................  Kings Canyon National            8.8         8.8        23.2        16.1
                                         Park.
                                        Sequoia National Park...
RAFA1.................................  San Rafael Wilderness            6.5         6.5        17.3        13.0
                                         Area.
DOME1.................................  Domeland Wilderness Area         5.1         5.1        17.2        13.7
SAGA1.................................  San Gabriel Wilderness           4.8         4.8        17.9        11.5
                                         Area.
                                        Cucamonga Wilderness
                                         Area.
SAGO1.................................  San Gorgonio Wilderness          5.4         5.4        20.4        12.0
                                         Area.
                                        San Jacinto Wilderness
                                         Area.
JOSH1.................................  Joshua Tree Wilderness           6.1         6.1        17.7        11.3
                                         Area.
AGTI..................................  Agua Tibia Wilderness            9.6         9.6        21.6        14.5
                                         Area.
----------------------------------------------------------------------------------------------------------------
Source: 2022 California Regional Haze Plan Table 8-1: 2028 Reasonable Progress Goals for California Class I
  Areas.

    In Plan appendix C, CARB also provided graphs of observed 
visibility, unadjusted and adjusted URP, and 2028 RPGs.\172\ From those 
CARB concluded that 2028 RPGs for all of California's Class I areas are 
on or below the adjusted URP glidepath.
---------------------------------------------------------------------------

    \172\ Those graphs have the unadjusted and adjusted URP 
glidepath lines crossing each other, instead of both starting at the 
2004 baseline level and having just the 2064 end point adjusted. 
However, comparable graphs available from WRAP TSS modeling tool 5 
show the same placement of 2028 RPG with respected to the unadjusted 
and adjusted URP glidepath line as the Plan appendix C graphs do. 
All Class I areas are below the unadjusted URP glidepath, except 
that those corresponding to IMPROVE sites REDW1, LAVO1, BLIS1, DOME1 
are above the unadjusted URP glidepath but below the glidepath 
adjusted for international sources and the glidepath adjusted for 
internationals sources and prescribed fire.

                                    Table 9--Current Rate of Progress and URP
----------------------------------------------------------------------------------------------------------------
                                                                 Current rate
             IMPROVE site                    Class I area         of progress    Unadjusted URP    Adjusted URP
                                                                   (dv/year)        (dv/year)        (dv/year)
----------------------------------------------------------------------------------------------------------------
LABE1................................  Lava Beds National                 0.11              0.09            0.07
                                        Monument.
                                       South Warner Wilderness
                                        Area.
REDW1................................  Redwood National Park..            0.08              0.09            0.07
TRIN1................................  Marble Mountain                    0.11              0.09            0.05
                                        Wilderness Area.
                                       Yolla Bolly-Middle Eel
                                        Wilderness Area.
LAVO1................................  Thousand Lakes                     0.09              0.09            0.06
                                        Wilderness Area.
                                       Lassen Volcanic
                                        National Park.
                                       Caribou Wilderness Area
BLIS1................................  Desolation Wilderness              0.06              0.09            0.06
                                        Area.
                                       Mokelumne Wilderness
                                        Area.
PORE1................................  Point Reyes National               0.29              0.16            0.14
                                        Seashore.
YOSE1................................  Emigrant Wilderness                0.14              0.12            0.08
                                        Area.
                                       Yosemite National Park.
HOOV1................................  Hoover Wilderness Area.            0.08              0.07            0.03
KAIS1................................  Ansel Adams Wilderness             0.14              0.11            0.06
                                        Area.
                                       John Muir Wilderness
                                        Area.
                                       Kaiser Wilderness Area.
PINN1................................  Pinnacles National Park            0.21              0.11            0.13
                                       Ventana Wilderness Area

[[Page 103758]]

 
SEQU1................................  Kings Canyon National              0.34              0.28            0.21
                                        Park.
                                       Sequoia National Park..
RAFA1................................  San Rafael Wilderness              0.23              0.18            0.14
                                        Area.
DOME1................................  Domeland Wilderness                0.15              0.18            0.13
                                        Area.
SAGA1................................  San Gabriel Wilderness             0.34              0.20            0.17
                                        Area.
                                       Cucamonga Wilderness
                                        Area.
SAGO1................................  San Gorgonio Wilderness            0.43              0.24            0.20
                                        Area.
                                       San Jacinto Wilderness
                                        Area.
JOSH1................................  Joshua Tree National               0.34              0.19            0.15
                                        Park.
AGTI1................................  Agua Tibia Wilderness              0.38              0.23            0.18
                                        Area.
----------------------------------------------------------------------------------------------------------------
Source: 2022 California Regional Haze Plan Tables 8-3, 8-4, and 8-5.

    As noted above, we find that CARB's long-term strategy does not 
meet the requirements of section 51.308(f)(2). Section 51.308(f)(3)(i) 
specifies that RPGs must reflect ``enforceable emissions limitations, 
compliance schedules, and other measures required under paragraph 
(f)(2) of this section.'' In the absence of an approved long-term 
strategy, we cannot approve the associated RPGs. In addition, CARB's 
RPGs for the clearest days are merely identical to baseline conditions, 
rather than estimated via a modeling-based analysis of the conditions 
that will be achieved at the end of the implementation period. We find 
that CARB's approach is inconsistent with the requirement 
51.308(f)(3)(i) for RPGs to ``reflect the visibility conditions that 
are projected to be achieved by the end of the applicable 
implementation period . . .'' Finally, we also note that CARB does not 
appear to have considered whether sources in California are reasonably 
anticipated to contribute to visibility impairment in a Class I area in 
another state, whose RPG for the most impaired days in that Class I 
area is above the URP, as required under 40 CFR 51.308(f)(3)(ii)(B). 
Based on these findings, we propose to determine that CARB has not 
satisfied the applicable requirements of 40 CFR 51.308(f)(3) relating 
to RPGs and to disapprove Chapter 8 of the Plan.

G. Additional Monitoring To Assess Reasonably Attributable Visibility 
Impairment

    Requirements under 40 CFR 51.308(f)(4) for additional monitoring to 
assess reasonably attributable visibility impairment are not applicable 
to California. The EPA and FLMs have not previously advised California 
that additional monitoring is needed to assess reasonably attributable 
visibility impairment. Therefore, the requirements under 40 CFR 
51.308(f)(4) are not applicable to California at this time.

H. Monitoring Strategy and Other Implementation Plan Requirements

    Section 51.308(f)(6) specifies that each comprehensive revision of 
a state's regional haze plan must contain or provide for certain 
elements, including monitoring strategies, emissions inventories, and 
any reporting, recordkeeping and other measures needed to assess and 
report on visibility. A main requirement of this subsection is for 
states with Class I areas to submit monitoring strategies for 
measuring, characterizing, and reporting on visibility impairment. 
Compliance with this requirement may be met through participation in 
the IMPROVE network. In Chapter 2 of the Plan, CARB noted that it 
relies on data from 17 monitoring sites operated by the IMPROVE network 
to track visibility conditions in California's Class I areas.
    Section 51.308(f)(6)(i) requires SIPs to provide for the 
establishment of any additional monitoring sites or equipment needed to 
assess whether RPGs to address regional haze for all mandatory Class I 
Federal areas within the state are being achieved. CARB stated that 
this requirement is ``not applicable,'' suggesting that CARB believes 
the current IMPROVE network is sufficient for this purpose.
    Section 51.308(f)(6)(ii) requires SIPs to provide for procedures by 
which monitoring data and other information are used in determining the 
contribution of emissions from within the state to regional haze 
visibility impairment at mandatory Class I Federal areas both within 
and outside the state. CARB relied on source-apportionment modeling 
performed by the WRAP to meet this requirement.\173\ Specifically, CARB 
pointed to both high-level source apportionment modeling, which was 
used to estimate how much of each haze pollutant was attributable to 
several broad source categories, and low-level source apportionment 
modeling, which was used to estimate how much ammonium nitrate and 
ammonium sulfate is attributable to regional human-made sources.
---------------------------------------------------------------------------

    \173\ Plan Chapter 4.
---------------------------------------------------------------------------

    Section 51.308(f)(6)(iii) does not apply to California, as it has a 
Class I area. Section 51.308(f)(6)(iv) requires the SIP to provide for 
the reporting of all visibility monitoring data to the Administrator at 
least annually for each Class I area in the state. As noted above, CARB 
relies on data from 17 monitoring sites operated by the IMPROVE 
Network.
    Section 51.308(f)(6)(v) requires the SIP to provide for a statewide 
inventory of emissions of pollutants that are reasonably anticipated to 
cause or contribute to visibility impairment, including emissions for 
the most recent year for which data are available and estimates of 
future projected emissions. It also requires a commitment to update the 
inventory periodically. California provides for emissions inventories 
and estimates of future projected emissions by participating in WRAP 
and by complying with the EPA's Air Emissions Reporting Rule (AERR). In 
40 CFR part 51, subpart A, the AERR requires states to submit updated 
emissions inventories for criteria pollutants to the EPA's Emissions 
Inventory System (EIS) annually or triennially depending on the source 
type. The EPA uses the inventory data from the EIS to develop the NEI, 
which is a comprehensive estimate of air emissions of criteria 
pollutants, criteria precursors, and hazardous air pollutants from air 
emissions sources. The EPA releases an NEI every three years. In 
Chapter 3 and appendix E of the Plan, CARB provides high-level 
summaries of 2014 and 2028 emissions inventories. The EPA proposes to 
find that CARB meets the requirements of 40 CFR

[[Page 103759]]

51.308(f)(6)(v) through its ongoing compliance with the AERR, its 
compilation of a statewide emissions inventories, and its use of WRAP 
modeling.
    Section 51.308(f)(6)(vi) requires the SIP to include other 
elements, including reporting, recordkeeping, and other measures, 
necessary to assess and report on visibility. The EPA proposes to find 
that CARB has met the requirements of 40 CFR 51.308(f)(6) as described 
above, including through its continued participation in the IMPROVE 
network and the WRAP, and that no further elements are necessary at 
this time for CARB to assess and report on visibility pursuant to 40 
CFR 51.308(f)(6)(vi).

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

    Section 51.308(f)(5) requires that periodic comprehensive revisions 
of states' regional haze plans also address the progress report 
requirements of 40 CFR 51.308(g)(1) through (5). The purpose of these 
requirements is to evaluate progress towards the applicable RPGs for 
each Class I area within the state and each Class I area outside the 
state that may be affected by emissions from within that state. 
Sections 51.308(g)(1) and (2) apply to all states and require a 
description of the status of implementation of all measures included in 
a state's first implementation period regional haze plan and a summary 
of the emission reductions achieved through implementation of those 
measures. Section 51.308(g)(3) applies only to states with Class I 
areas within their borders and requires such states to assess current 
visibility conditions, changes in visibility relative to baseline 
(2000-2004) visibility conditions, and changes in visibility conditions 
relative to the period addressed in the first implementation period 
progress report. Section 51.308(g)(4) applies to all states and 
requires an analysis tracking changes in emissions of pollutants 
contributing to visibility impairment from all sources and sectors 
since the period addressed by the first implementation period progress 
report. This provision further specifies the year or years through 
which the analysis must extend depending on the type of source and the 
platform through which its emissions information is reported. Finally, 
section 51.308(g)(5), which also applies to all states, requires an 
assessment of any significant changes in anthropogenic emissions within 
or outside the state have occurred since the period addressed by the 
first implementation period progress report, including whether such 
changes were anticipated and whether they have limited or impeded 
expected progress towards reducing emissions and improving visibility.
    CARB's most recent 5-year progress report was submitted to the EPA 
on June 16, 2014 and presented data analysis for the period 2007-
2011.\174\ Therefore, the current progress report is required to 
address the time period beginning in 2012.
---------------------------------------------------------------------------

    \174\ 79 FR 58302, 58304 (September 29, 2014).
---------------------------------------------------------------------------

    CARB addressed the requirements of 40 CFR 51.308(g) in Chapter 10 
of the Plan and provided additional supporting information in a 
technical supplement submitted on August 24, 2023 (``2023 California 
Regional Haze Technical Supplement'').\175\ Specifically, to address 
51.308(g)(1) and (2), CARB provided a summary of control measures it 
adopted between 2012 and 2018, and statewide emissions trends through 
2018.\176\
---------------------------------------------------------------------------

    \175\ Letter dated August 23, 2023, from Michael Benjamin, 
Division Chief, Air Quality Planning and Science Division, to 
Matthew Lakin, Acting Director, Air and Radiation Division, Region 9 
(submitted electronically August 24, 2023).
    \176\ Plan table 10-1 and Figure 10-1.
---------------------------------------------------------------------------

    The EPA proposes to find that the Plan meets the requirements of 40 
CFR 51.308(g)(1) and (2) because it describes the measures included in 
the long-term strategy from the first implementation period, as well as 
the status of their implementation and the emissions reductions 
achieved through such implementation.
    The Plan also provides the 5-year baseline (2000-2004) visibility 
conditions, the conditions covered in the previous progress report 
(2007-2011) and current conditions (2014-2018) for the clearest and 
most impaired days.\177\ The EPA therefore proposes to find that the 
Plan meets the requirements of 40 CFR 51.308(g)(3).
---------------------------------------------------------------------------

    \177\ Id. Tables 10-4 and 10-5.
---------------------------------------------------------------------------

    In the 2023 California Regional Haze Technical Supplement, CARB 
provided additional supporting information to address the requirements 
of 40 CFR 51.308(g)(4) and (5). Pursuant to section 51.308(g)(4), CARB 
provided a summary of emissions of NOX, SO2, 
PM10, PM2.5, VOCs, and NH3 from all 
sources and activities, including from point, nonpoint, non-road 
mobile, and on-road mobile sources for the progress report period. CARB 
also provided 2012-2019 clean air markets program data for all sources 
with emissions of visibility impairing pollutants. The EPA is therefore 
proposing to find that the Plan satisfies the requirements of section 
51.308(g)(4) by providing emissions information for NOX, 
SO2, PM10, PM2.5, VOCs, and 
NH3 broken down by type of sources and activities within the 
state.
    Pursuant to section 51.308(g)(5), CARB provided an assessment of 
any significant changes in anthropogenic emissions within or outside 
the state that have occurred since the period addressed in the most 
recent plan, including whether or not these changes in anthropogenic 
emissions were anticipated in that most recent plan, and whether they 
have limited or impeded progress in reducing pollutant emissions and 
improving visibility. CARB noted overall average emissions reductions 
of 36 percent for NOX, 45 percent for SO2, 20 
percent for ROG, and 28 percent for PM2.5 between the 2007-
2011 period and the 2014-2018 period. The EPA proposes to find the Plan 
meets the requirements of section 51.308(g)(5).

J. Requirements for State and Federal Land Manager Coordination

    CAA section 169A(d) requires states to consult with FLMs before 
holding the public hearing on a proposed regional haze SIP, and to 
include a summary of the FLMs' conclusions and recommendations in the 
notice to the public. In addition, the FLM consultation provision in 
section 51.308(i)(2) requires a state to provide FLMs with an 
opportunity for consultation that is early enough in the state's policy 
analyses of its emissions reduction obligation so that information and 
recommendations provided by the FLMs can meaningfully inform the 
state's decisions on its long-term strategy. If the consultation has 
taken place at least 120 days before a public hearing or public comment 
period, the opportunity for consultation will be deemed early enough. 
Regardless, the opportunity for consultation must be provided at least 
sixty days before a public hearing or public comment period at the 
state level. Section 51.308(i)(2) also provides two substantive topics 
on which FLMs must be provided an opportunity to discuss with states: 
assessment of visibility impairment in any Class I area and 
recommendations on the development and implementation of strategies to 
address visibility impairment. Section 51.308(i)(3) requires states, in 
developing their implementation plans, to include a description of how 
they addressed FLM comments. Section 51.308(i)(4) requires regional 
haze plans to provide procedures for continuing consultation between 
the State and FLMs on the implementation of the regional haze program, 
including development and review of SIP revisions and progress reports, 
and on

[[Page 103760]]

the implementation of other programs having the potential to contribute 
to impairment of visibility in mandatory Class I Federal areas.
    In Chapter 9 of the Plan, CARB indicates that it held multiple 
informal consultation teleconferences with staff from the NPS and the 
USFS during development of its plan.\178\ CARB sent a draft of the Plan 
to the NPS, FWS, and the USFS on February 9, 2022. CARB requested that 
FLM agencies provide formal comments on the draft by April 11, 2022. 
The comments received from Federal land managers and CARB's responses 
to these comments are provided in appendix I of the Plan. Chapter 9 
also includes a discussion of CARB's procedures for continuing 
consultation with stakeholders, including FLMs.
---------------------------------------------------------------------------

    \178\ Plan, p. 141.
---------------------------------------------------------------------------

    While CARB did take administrative steps to provide the FLMs the 
requisite opportunity to review and provide feedback on the state's 
initial draft plan, the EPA cannot approve the requirements under 
51.308(f)(i) because CARB's consultation was based on a SIP revision 
that did not meet the required statutory and regulatory requirements of 
the CAA and the RHR, respectively. In addition, if the EPA finalizes 
the partial approval and partial disapproval of the Plan, as proposed 
in this document, in the process of correcting the deficiencies 
outlined above with respect to the RHR and statutory requirements, the 
State (or the EPA in the case of an eventual FIP) will be required to 
again satisfy the FLM consultation requirement under 51.308(i).

V. Proposed Action

    For the reasons discussed in this notice, under CAA section 
110(k)(3), the EPA is proposing to partially approve and partially 
disapprove the 2022 California Regional Haze Plan. The EPA is proposing 
to approve the elements of the Plan related to requirements contained 
in 40 CFR 51.308(f)(1), 40 CFR 51.308(f)(4)-(6), and 40 CFR 51.308 
(g)(1)-(5). The EPA is proposing to disapprove the elements of the Plan 
related to requirements contained in 40 CFR 51.308(f)(2), 40 CFR 
51.308(f)(3), and 40 CFR 51.308(i)(2)-(4).
    Under section 179(a) of the CAA, final disapproval of a submittal 
that addresses a requirement of part D, title I of the CAA or is 
required in response to a finding of substantial inadequacy as 
described in CAA section 110(k)(5) (SIP Call) starts a sanctions clock. 
The 2022 California Regional Haze Plan was not submitted to meet any of 
these requirements. Therefore, if finalized, these disapprovals would 
not trigger any offset or highway sanctions clocks. Disapproving a SIP 
submission also establishes a two-year deadline for the EPA to 
promulgate a FIP to address the relevant requirements under CAA section 
110(c), unless the EPA approves a subsequent SIP submission that meets 
these requirements.

VI. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the Act and applicable 
Federal regulations.\179\ Thus, in reviewing SIP submissions, the EPA's 
role is to review state choices, and approve those choices if they meet 
the minimum criteria of the Act. Accordingly, this proposed rulemaking 
proposes to partially approve and partially disapprove state law as 
meeting Federal requirements and does not impose additional 
requirements beyond those imposed by state law.
---------------------------------------------------------------------------

    \179\ 42 U.S.C. 7410(k); 40 CFR 52.02(a).
---------------------------------------------------------------------------

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is not a significant regulatory action and was 
therefore not submitted to the Office of Management and Budget (OMB) 
for review.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the PRA because this action does not impose additional requirements 
beyond those imposed by state law.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities beyond those 
imposed by state law.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. This action does not impose additional requirements 
beyond those imposed by state law. Accordingly, no additional costs to 
state, local, or Tribal governments, or to the private sector, will 
result from this action.

E. Executive Order 13132: Federalism

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

F. Executive Order 13175: Coordination With Indian Tribal Governments

    This action does not have Tribal implications, as specified in 
Executive Order 13175, because the SIP is not approved to apply on any 
Indian reservation land or in any other area where the EPA or an Indian 
Tribe has demonstrated that a Tribe has jurisdiction, and will not 
impose substantial direct costs on Tribal governments or preempt Tribal 
law. Thus, Executive Order 13175 does not apply to this action.

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

    The EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that the EPA has reason to believe may disproportionately affect 
children, per the definition of ``covered regulatory action'' in 
section 2-202 of the Executive Order. Therefore, this action is not 
subject to Executive Order 13045 because it merely proposes to 
partially approve and partially disapprove state law as meeting Federal 
requirements. Furthermore, the EPA's Policy on Children's Health does 
not apply to this action.

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

    This action is not subject to Executive Order 13211, because it is 
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act (NTTAA)

    Section 12(d) of the NTTAA directs the EPA to use voluntary 
consensus standards in its regulatory activities unless to do so would 
be inconsistent with applicable law or otherwise impractical. The EPA 
believes that this action is not subject to the requirements of section 
12(d) of the NTTAA because application of those requirements would be 
inconsistent with the CAA.

[[Page 103761]]

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

    Executive Order 12898 (Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations, 59 FR 7629, 
Feb. 16, 1994) directs Federal agencies to identify and address 
``disproportionately high and adverse human health or environmental 
effects'' of their actions on minority populations and low-income 
populations to the greatest extent practicable and permitted by law. 
Executive Order 14096 (Revitalizing Our Nation's Commitment to 
Environmental Justice for All, 88 FR 25251, April 26, 2023) builds on 
and supplements E.O. 12898 and defines EJ as, among other things, ``the 
just treatment and meaningful involvement of all people, regardless of 
income, race, color, national origin, or Tribal affiliation, or 
disability in agency decision-making and other Federal activities that 
affect human health and the environment.''
    The State did not evaluate EJ considerations as part of its SIP 
submittal; the CAA and applicable implementing regulations neither 
prohibit nor require such an evaluation. The EPA did not perform an EJ 
analysis and did not consider EJ in this action. Due to the nature of 
the action being taken here, if finalized, this action is expected to 
have a neutral to positive impact on the air quality of the affected 
area. Consideration of EJ is not required as part of this action, and 
there is no information in the record inconsistent with the stated goal 
of E.O. 12898/14096 of achieving environmental justice for communities 
with EJ concerns.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Nitrogen dioxide, 
Ozone, Particulate matter, Sulfur oxides.

    Dated: December 10, 2024.
Martha Guzman Aceves,
Regional Administrator, Region IX.
[FR Doc. 2024-29595 Filed 12-18-24; 8:45 am]
BILLING CODE 6560-50-P`