Rule2025-21340
Air Plan Approval; Montana; Regional Haze Plan for the Second Implementation Period
Primary source
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Published
November 28, 2025
Effective
December 29, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is approving a regional haze state implementation plan (SIP) revision submitted by the State of Montana on August 10, 2022 (Montana's 2022 SIP submission), as satisfying applicable requirements under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. The EPA is also finalizing approval of the prong 4 visibility portion of Montana's October 1, 2018, Infrastructure SIP submission for the 2015 ozone National Ambient Air Quality Standard (NAAQS). The EPA is taking this action pursuant to the CAA.
Full Text
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<title>Federal Register, Volume 90 Issue 227 (Friday, November 28, 2025)</title>
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[Federal Register Volume 90, Number 227 (Friday, November 28, 2025)]
[Rules and Regulations]
[Pages 54586-54588]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-21340]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R08-OAR-2024-0608; FRL-12597-02-R8]
Air Plan Approval; Montana; Regional Haze Plan for the Second
Implementation Period
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: The Environmental Protection Agency (EPA) is approving a
regional haze state implementation plan (SIP) revision submitted by the
State of Montana on August 10, 2022 (Montana's 2022 SIP submission), as
satisfying applicable requirements under the Clean Air Act (CAA) and
the EPA's Regional Haze Rule (RHR) for the program's second
implementation period. The EPA is also finalizing approval of the prong
4 visibility portion of Montana's October 1, 2018, Infrastructure SIP
submission for the 2015 ozone National Ambient Air Quality Standard
(NAAQS). The EPA is taking this action pursuant to the CAA.
DATES: This rule is effective on December 29, 2025.
ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-R08-OAR-2024-0608. All documents in the docket are
listed on the <a href="https://www.regulations.gov">https://www.regulations.gov</a> website. Although listed in
the index, some information is not publicly available, e.g.,
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Certain other material, such as
copyrighted material, is not placed on the internet and will be
publicly available only in hard copy form. Publicly available docket
materials are available through <a href="https://www.regulations.gov">https://www.regulations.gov</a>, or please
contact the person identified in the FOR FURTHER INFORMATION CONTACT
section for additional availability information.
FOR FURTHER INFORMATION CONTACT: Amrita Singh, Air and Radiation
Division, EPA, Region 8, Mailcode 8ARD-IO, 1595 Wynkoop Street, Denver,
Colorado 80202-1129, telephone number: (303) 312-6103; email address:
<a href="/cdn-cgi/l/email-protection#4c3f25222b24622d213e25382d0c293c2d622b233a"><span class="__cf_email__" data-cfemail="76051f18111e58171b041f02173613061758111900">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document ``we,'' ``us,'' and
``our'' means the EPA.
Table of Contents
I. What is being addressed in this document?
II. Background
III. Public Comments and EPA Responses
IV. Final Action
V. Statutory and Executive Order Reviews
I. What is being addressed in this document?
The EPA is approving a SIP revision submitted by the State of
Montana to the EPA on August 10, 2022, addressing the requirements of
the second implementation period of the RHR. As required by section
169A of the CAA, the RHR calls for state and federal agencies to work
together to improve visibility in 156 national parks and wilderness
areas. The rule requires the states, in coordination with the EPA, the
National Park Service, Fish and Wildlife Service, the Forest Service,
and other interested parties, to develop and implement air quality
protection plans to reduce the pollution that causes visibility
impairment in mandatory Class I Federal areas. Visibility impairing
pollutants include fine and coarse particulate matter (PM) (e.g.,
sulfates, nitrates, organic carbon, elemental carbon, and soil dust)
and their precursors (e.g., sulfur dioxide (SO<INF>2</INF>), oxides of
nitrogen (NO<INF>X</INF>), and, in some cases, volatile organic
compounds (VOC) and ammonia (NH<INF>3</INF>)). As discussed in further
detail in our proposed rule, this document, and the accompanying
Response to Comments
[[Page 54587]]
(RTC) document, the EPA finds that Montana submitted a regional haze
SIP that meets all the regional haze requirements for the second
implementation period. The State's submission, the proposed rule, and
the RTC document can be found in the docket for this action.
II. Background
On August 10, 2022, Montana submitted a revision to its SIP to
address its regional haze obligations for the second implementation
period (2018-2028). Montana made this revision to satisfy the
requirements of the CAA's regional haze program pursuant to CAA
sections 169A and 169B and 40 Code of Federal Regulations (CFR) 51.308.
On September 11, 2025, the EPA proposed to approve Montana's 2022
SIP submission.\1\ Specifically, the EPA proposed to approve Montana's
2022 SIP submission as satisfying the requirements of 40 CFR
51.308(f)(1): calculations of baseline, current, and natural visibility
conditions, progress to date, and the uniform rate of progress; 40 CFR
51.308(f)(2): long-term strategy; 40 CFR 51.308(f)(3): reasonable
progress goals; 40 CFR 51.308(f)(4): reasonably attributable visibility
impairment; 40 CFR 51.308(f)(5) and 40 CFR 51.308(g): progress report
requirements; 40 CFR 51.308(f)(6): monitoring strategy and other
implementation plan requirements; and 40 CFR 51.308(i): Federal Land
Manager (FLM) consultation. Our public comment period closed on October
14, 2025.
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\1\ 90 FR 43958 (September 11, 2025).
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The September 11, 2025, proposed rule provided background on the
requirements of the CAA and RHR, a summary of Montana's regional haze
SIP submittal and related EPA actions, and the EPA's rationale for its
proposed action. That background and rationale will not be restated
here. For the reasons stated in the proposed rule, this document, and
in the accompanying RTC document, the EPA concludes that Montana's 2022
SIP submission meets the requirements of the CAA and RHR.
III. Public Comments and EPA Responses
The public comment period on the proposal closed on October 14,
2025. During the public comment period, we received 16 comments on our
proposal: 1 in support and 15 in opposition. The commenters were:
Conservation Groups,\2\ the Mid-Atlantic/Northeast Visibility Union
(MANEVU),\3\ Cabinet Resource Group,\4\ Talen Montana,\5\ and eight
individual commenters.\6\ The full text of comments received is
included in the publicly posted docket associated with this action at
<a href="https://www.regulations.gov">https://www.regulations.gov</a>. Our RTC document, which is also included
in the docket associated with this action, provides detailed responses
to all significant comments received.
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\2\ Letter dated October 14, 2025.
\3\ Letter dated October 14, 2025.
\4\ Letter dated October 14, 2025.
\5\ Letter dated October 14, 2025.
\6\ Letters dated from September 29, 2025 to October 14, 2025.
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IV. Final Action
For the reasons stated in the preamble to the proposed rule, in the
RTC document, and in this document, we are approving Montana's 2022 SIP
submission. Specifically, we are approving Montana's 2022 SIP
submission relating to CAA 169A:
<bullet> Calculations of baseline, current, and natural visibility
conditions, progress to date, and uniform rate of progress (40 CFR
51.308(f)(1));
<bullet> Long-term strategy (40 CFR 51.308(f)(2));
<bullet> Reasonable progress goals (40 CFR 51.308(f)(3));
<bullet> Reasonably attributable visibility impairment (40 CFR
51.308(f)(4));
<bullet> Progress report requirements (40 CFR 51.308(f)(5) and 40
CFR 51.308(g));
<bullet> Monitoring strategy and other implementation plan
requirements (40 CFR 51.308(f)(6));
<bullet> FLM consultation (40 CFR 51.308(i)).
In addition, we are approving the prong 4 visibility portion of
Montana's October 1, 2018 Infrastructure SIP submission for the 2015
ozone NAAQS.
V. 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. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, the EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely proposes to approve state law as meeting Federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this action:
<bullet> Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Orders
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21,
2011);
<bullet> Is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because State Implementation Plan approvals under the
CAA are exempt from review under Executive Order 12866;
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
<bullet> Does not contain any unfunded mandate or significantly or
uniquely affect small governments, described in the Unfunded Mandates
Reform Act of 1995 (Pub. L. 104-4);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a state program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
<bullet> Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian Tribe has
demonstrated that a Tribe has jurisdiction. In those areas of Indian
country, the rule does not have Tribal implications and will not impose
substantial direct costs on Tribal governments or preempt Tribal law as
specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
This action is subject to the Congressional Review Act (CRA), and
EPA will submit a rule report to each House of the Congress and to the
Comptroller General of the United States. This action is not a ``major
rule'' as defined by 5 U.S.C. 804(2).
Under section 307(b)(1) of the CAA, petitions for judicial review
of this action must be filed in the United States Court of Appeals for
the appropriate circuit by January 27, 2026. Filing a petition for
reconsideration by the Administrator of this final rule does not affect
the finality of this action for the purposes of judicial review nor
does it extend the time within which a petition for judicial review may
be filed, and shall not postpone the effectiveness of such rule or
action. This action may not be challenged later in proceedings to
enforce its requirements (see section 307(b)(2)).
[[Page 54588]]
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Carbon monoxide,
Greenhouse gases, Incorporation by reference, Intergovernmental
relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting
and recordkeeping requirements, Sulfur oxides, Volatile organic
compounds.
Dated: November 17, 2025.
Cyrus M. Western,
Regional Administrator, Region 8.
For the reasons stated in the preamble, the Environmental
Protection Agency is amending 40 CFR part 52 as follows:
PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS
0
1. The authority citation for part 52 continues to read as follows:
Authority: 42 U.S.C. 7401 et seq.
Subpart BB--Montana
0
2. In Sec. 52.1370:
0
a. Amend the table in paragraph (e) by:
0
i. Under the center heading ``(1) Statewide'', adding the entries
``Montana Regional Haze State Implementation Plan'' and ``Interstate
Transport Requirements of the CAA, section 110(a)(2)(D)(i)(II) prong 4,
for the 2015 Ozone NAAQS'' after the entry ``Interstate Transport
Requirements of the CAA, section 110(a)(2)(D)(i)(I), for the 2015 Ozone
NAAQS'' to read as follows:
Sec. 52.1370 Identification of plan.
* * * * *
(e) * * *
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State Notice of
Title/subject effective final rule NFR citation
date date
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(1) Statewide
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Montana Regional Haze State 8/10/2022 11/28/2025 90 FR [insert
Implementation Plan. Federal
Register page
where the
document
begins].
Interstate Transport 8/22/2018 11/28/2025 90 FR [insert
Requirements of the CAA, Federal
section 110(a)(2)(D)(i)(II) Register page
prong 4, for the 2015 Ozone where the
NAAQS. document
begins].
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[FR Doc. 2025-21340 Filed 11-26-25; 8:45 am]
BILLING CODE 6560-50-P
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