Proposed Rule2025-17502
Approval of Air Quality Implementation Plans; Arizona; Arizona Department of Environmental Quality; Stationary Source Permits; West Pinal County; PM10
Primary source
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Published
September 11, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to fully approve the Arizona Department of Environmental Quality's (ADEQ or "State") State Implementation Plan (SIP) submittal under the Clean Air Act (CAA or "the Act") that addresses Nonattainment New Source Review (NNSR) permitting of precursor emissions for the 1987 National Ambient Air Quality Standards (NAAQS or "standard") for particulate matter with a diameter of 10 micrometers or less (PM<INF>10</INF>) in the West Pinal PM<INF>10</INF> nonattainment area. We are taking comments on this proposal and plan to follow with a final action.
Full Text
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<title>Federal Register, Volume 90 Issue 174 (Thursday, September 11, 2025)</title>
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[Federal Register Volume 90, Number 174 (Thursday, September 11, 2025)]
[Proposed Rules]
[Pages 43980-43983]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-17502]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2025-1113; FRL-12927-01-R9]
Approval of Air Quality Implementation Plans; Arizona; Arizona
Department of Environmental Quality; Stationary Source Permits; West
Pinal County; PM10
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
fully approve the Arizona Department of Environmental Quality's (ADEQ
or ``State'') State Implementation Plan (SIP) submittal under the Clean
Air Act (CAA or ``the Act'') that addresses Nonattainment New Source
Review (NNSR) permitting of precursor emissions for the 1987 National
Ambient Air Quality Standards (NAAQS or ``standard'') for particulate
matter with a diameter of 10 micrometers or less (PM<INF>10</INF>) in
the West Pinal PM<INF>10</INF> nonattainment area. We are taking
comments on this proposal and plan to follow with a final action.
DATES: Comments must be received on or before October 14, 2025.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2025-1113 at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the online
instructions for submitting comments. Once submitted, comments cannot
be edited or removed from <a href="http://Regulations.gov">Regulations.gov</a>. The EPA may publish any
comment received to its public docket. Do not submit electronically any
information you consider to be Confidential Business Information (CBI)
or other information the disclosure of which 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 <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>. If you need assistance in a language other than English or if
you are a person with disabilities 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: Shaheerah Kelly, U.S. Environmental
Protection Agency, Region IX (AIR-3-2), telephone number: (415) 947-
4156, email address: <a href="/cdn-cgi/l/email-protection#365d535a5a4f18455e575e535344575e7653465718515940"><span class="__cf_email__" data-cfemail="e08b858c8c99ce938881888585928188a0859081ce878f96">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,''
and ``our'' refer to the EPA.
Table of Contents
I. Regulatory Context and Background
A. PM<INF>10</INF> NAAQS and West Pinal Area Designation and
Classification
B. CAA NNSR Requirements for PM<INF>10</INF> Nonattainment Area
SIPs Under CAA Section 189(e)
C. The EPA's Previous Actions on the ADEQ's NNSR Program for
PM<INF>10</INF> for the West Pinal PM<INF>10</INF> Nonattainment
Area
II. The ADEQ's 2023 SIP Submission Addressing the Requirements of
CAA Section 189(e) for the ADEQ's PM<INF>10</INF> NNSR Program in
the West Pinal PM<INF>10</INF> Nonattainment Area
III. Evaluation of PM<INF>10</INF> Precursors in the West Pinal
PM<INF>10</INF> Nonattainment Area for the ADEQ's NNSR Program Under
CAA Section 189(e) and 40 CFR 51.165(a)(10)
A. The EPA's PM<INF>10</INF> Precursor Evaluation and
Determination
B. Determination Regarding the ADEQ's NNSR Program for
PM<INF>10</INF> in the West Pinal PM<INF>10</INF> Nonattainment Area
IV. Proposed Action
V. Statutory and Executive Order Reviews
I. Regulatory Context and Background
A. PM10 NAAQS and West Pinal Area Designation and Classification
The EPA sets the NAAQS for certain ambient air pollutants at levels
required to protect human health and the environment. Particulate
matter with an aerodynamic diameter less than or equal to a nominal ten
micrometers, or PM<INF>10</INF>, is one of these ambient air pollutants
for which the EPA has established health-based standards. On July 1,
1987, the EPA promulgated two primary standards for PM<INF>10</INF>: a
24-hour standard of 150 micrograms per cubic meter ([micro]g/m\3\); and
an annual PM<INF>10</INF> standard of 50 [micro]g/m\3\. The EPA also
promulgated secondary PM<INF>10</INF> standards that were identical to
the primary standards. 52 FR 24634 (July 1, 1987). Because they are
identical, we refer to the primary and secondary standards using the
singular term, NAAQS. Effective December 18, 2006, the EPA revoked the
annual PM<INF>10</INF> NAAQS but retained the 24-hour PM<INF>10</INF>
NAAQS. 71 FR 61144 (October 17, 2006).
Effective July 2, 2012, the EPA designated a portion of state lands
in Pinal County, Arizona, (``West Pinal'') as nonattainment for the
1987 p.m.<INF>10</INF> NAAQS.\1\ West Pinal is located in central
Arizona, southeast of the Phoenix metropolitan area and northwest of
the city of Tucson. Pinal County covers 5,365 square miles and has two
distinct western and eastern regions with different characteristics
relevant to pollution formation. The West Pinal PM<INF>10</INF>
nonattainment area is located within the western region.
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\1\ 77 FR 32024 (May 31, 2012). The precise boundaries for the
West Pinal PM<INF>10</INF> nonattainment area are described in 40
CFR 81.303.
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As a result of this nonattainment designation, EPA initially
classified West Pinal as a ``Moderate'' PM<INF>10</INF> nonattainment
area.\2\ Pursuant to CAA section 188(b)(2), the EPA later determined
that the West Pinal nonattainment area had not attained the 1987 24-
hour PM<INF>10</INF> NAAQS by the attainment date for the area, which
resulted in the area's reclassification as a ``Serious''
PM<INF>10</INF> nonattainment area, effective July 24, 2020.\3\
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\2\ See 77 FR 32024, 32030, 32032.
\3\ 85 FR 37756 (June 24, 2020).
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B. CAA NNSR Requirements for PM10 Nonattainment Area SIPs Under CAA
Section 189(e)
The Act's preconstruction permitting requirements for stationary
sources, also called New Source Review (NSR), are found in title I of
the Act and in the EPA's implementing regulations addressing the SIP
requirements for state NSR programs at 40 CFR part 51, subpart I. The
EPA's designation of West Pinal as a nonattainment area for the 1987
PM<INF>10</INF> NAAQS triggered the requirement for the ADEQ to develop
and submit an NNSR program to the EPA for SIP approval for that
nonattainment area pursuant to CAA sections 172(c)(5) and 173 and 40
CFR 51.160-51.165, which must satisfy the NNSR requirements applicable
to PM<INF>10</INF> nonattainment areas.
Among other CAA requirements applicable to PM<INF>10</INF>
nonattainment areas, section 189(e) of the Act requires that the
control requirements for major stationary sources of direct
PM<INF>10</INF> also apply to major stationary sources of
PM<INF>10</INF> precursors, except where the EPA determines that such
sources do not
[[Page 43981]]
contribute significantly to PM<INF>10</INF> levels that exceed the
standard in the area. The EPA's regulations implementing state NNSR
program requirements likewise provide that the state NNSR program
requirements at 40 CFR 51.165 that are applicable to major stationary
sources and major modifications of PM<INF>10</INF> must also apply to
major stationary sources and major modifications of PM<INF>10</INF>
precursors, except where the EPA determines that such sources do not
contribute significantly to PM<INF>10</INF> levels that exceed the
PM<INF>10</INF> NAAQS in the area. 40 CFR 51.165(a)(10).
C. The EPA's Previous Actions on the ADEQ's NNSR Program for PM10 for
the West Pinal PM10 Nonattainment Area
In November 2015, the EPA issued a final rule taking action on a
comprehensive 2012 NSR SIP submittal from the ADEQ that constituted a
major update to the ADEQ's NSR program (``2015 NSR action''). 80 FR
67319 (Nov. 2, 2015). The EPA determined that this SIP submittal met
most NSR requirements and significantly strengthened ADEQ's NSR
program. However, the EPA also identified deficiencies with various
aspects of the SIP submittal, and therefore the EPA's 2015 NSR action
was a limited approval and limited disapproval of the ADEQ's NNSR
program for all areas within the ADEQ's jurisdiction, including but not
limited to the West Pinal PM<INF>10</INF> nonattainment area, based on
the program not meeting certain NNSR program requirements. 80 FR 67319,
67321, 67332.
The EPA's 2015 NSR action also included additional actions,
including a separate limited approval of the ADEQ's NNSR program for
PM<INF>10</INF> only with respect to the West Pinal PM<INF>10</INF>
nonattainment area, based on the requirements of section 189(e) of the
Act, without an accompanying limited disapproval. 80 FR 67319, 67332;
see also 80 FR 14044, 14058, 14060 (Mar. 18, 2015) (proposed rulemaking
for the 2015 NSR action).\4\ The EPA explained the basis for this
limited approval specific to the West Pinal PM<INF>10</INF>
nonattainment area in its proposal for the 2015 NSR action.
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\4\ The ADEQ has permitting jurisdiction over major stationary
sources in Pinal County. See 80 FR 14044, 14045.
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In the proposal, the EPA observed that CAA section 189(e) requires
that the ADEQ's NNSR program for PM<INF>10</INF> nonattainment areas
apply to major stationary sources of PM<INF>10</INF> precursors unless
the EPA determines that such sources do not contribute significantly to
PM<INF>10</INF> levels, which exceed the standard in the area. The EPA
noted that while the ADEQ's NSR SIP submittal generally included NNSR
requirements for PM<INF>10</INF> nonattainment areas, such as the
PM<INF>10</INF> significant emissions rate, the regulation of
PM<INF>10</INF> condensable emissions, and the applicable emissions
offset requirements, the submittal contained a number of deficiencies.
The EPA explained that as a result of these deficiencies it was
proposing a limited approval and limited disapproval of the ADEQ's NNSR
submittal.
More importantly for the purposes of this proposed action, the EPA
explained that separate and aside from the issues identified in the
EPA's proposed limited approval and limited approval of ADEQ's NNSR
submittal, the EPA was not prepared at that time to grant full approval
to the ADEQ's NSR SIP submittal as to the PM<INF>10</INF> NNSR program
requirements specifically for the West Pinal nonattainment area in
light of the requirements in CAA section 189(e). The EPA explained that
the evaluation of which PM<INF>10</INF> precursors need to be
controlled to achieve the PM<INF>10</INF> standard in a particular area
is typically conducted in the context of the state's preparation and
the EPA's review of an area's attainment plan. The EPA further
explained that it did not have such a plan before it for West Pinal at
that time and therefore did not have the state's precursor analysis,
and that it could not fully approve, as complying with the CAA, a NNSR
SIP submission that did not address PM<INF>10</INF> precursors. 80 FR
14044, 14058.
The EPA further noted in the proposal that while the ADEQ's
submittal may not contain all of the elements necessary to satisfy the
CAA NNSR requirements, the revisions to the ADEQ's NNSR program
represented a considerable strengthening of the Arizona SIP, which,
until that time, did not address NSR requirements for PM<INF>10</INF>
at all. The EPA therefore proposed a limited approval of the
PM<INF>10</INF> NNSR provisions in the ADEQ's NSR submittal as they
apply to the West Pinal PM<INF>10</INF> nonattainment area, recognizing
the need to address the requirements of CAA section 189(e). The EPA
indicated that once the ADEQ submitted a new PM<INF>10</INF> attainment
plan for the West Pinal PM<INF>10</INF> nonattainment area, the EPA
would consider whether a limited disapproval should also be proposed
based on CAA section 189(e). 80 FR 14044, 14058. The EPA received no
comments on our proposed limited approval for the ADEQ's NNSR program
for PM<INF>10</INF> for the West Pinal PM<INF>10</INF> nonattainment
area based on CAA section 189(e), and we finalized this portion of our
action as proposed. See 80 FR 67319, 67332 and n.29.
Following the 2015 NSR action, the ADEQ submitted, and the EPA
acted on, a number of subsequent NSR SIP submittals, both to address
the deficiencies that formed the bases for the EPA's limited
disapproval of the ADEQ's NSR program in the 2015 NSR action and to
make other updates to its NSR program. Among these actions, in a 2018
rulemaking, the EPA reviewed and approved revisions to the ADEQ's NNSR
program into the Arizona SIP that were intended to address the
deficiencies with the ADEQ's NNSR program that had been identified by
the EPA in its 2015 limited disapproval of the ADEQ's NNSR rules. See
83 FR 19631 (May 4, 2018) (the ``2018 Major NSR action''). The EPA
determined in the 2018 Major NSR action that the ADEQ's revised NNSR
rules addressed the deficiencies in the ADEQ's NNSR program under Part
D of the CAA that had formed the basis for its limited disapproval of
the NNSR program in the 2015 NSR action for PM<INF>10</INF> and other
nonattainment pollutants.\5\ The issue of whether PM<INF>10</INF>
precursors must be regulated by the ADEQ under the NNSR program in the
West Pinal PM<INF>10</INF> nonattainment area pursuant to CAA section
189(e) and 40 CFR 51.165(a)(10) was not a basis for the EPA's limited
disapproval in its 2015 NSR action, and the ADEQ SIP submittal that the
EPA acted on in the 2018 Major NSR action did not address this issue;
therefore, the EPA did not address the issue as part of the 2018 Major
NSR action.\6\
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\5\ 83 FR 19631-19634; see also 82 FR 25213, 25215-25217, 25220
(Jun. 1, 2017) (proposed rulemaking for the 2018 Major NSR action).
The 2018 Major NSR action also included a conditional approval
related to the ADEQ's regulation of ammonia as a PM<INF>2.5</INF>
precursor under the NNSR program. See 83 FR 19631, 19633. After the
ADEQ submitted further revisions to its NSR program to address this
issue, the EPA took action to change this specific conditional
approval to a full approval. See 86 FR 31927 (Jun. 16, 2021).
\6\ Following the 2018 Major NSR action, the EPA took additional
rulemaking actions approving revisions to the ADEQ's SIP-approved
NSR program; however, none of these actions was specific to the
ADEQ's NNSR program for PM<INF>10</INF> or addressed the issue of
whether the ADEQ's NNSR program for PM<INF>10</INF> for West Pinal
was consistent with CAA section 189(e) and 40 CFR 51.165(a)(10). See
86 FR 31927 (Jun. 16, 2021); 89 FR 22963 (Apr. 3, 2024).
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II. The ADEQ's 2023 SIP Submission Addressing the Requirements of CAA
Section 189(e) for the ADEQ's PM10 NNSR Program in the West Pinal PM10
Nonattainment Area
On December 15, 2023, the ADEQ submitted the ``2023 Five Percent
Particulate Plan for PM-10 for the West Pinal County Nonattainment
Area'' (``2023 PM<INF>10</INF> Plan'') as a revision to the Arizona
SIP. The ADEQ is the
[[Page 43982]]
governor's designee for submitting official revisions of the Arizona
SIP to the EPA. The EPA reviewed this December 2023 SIP submission for
completeness, and we issued a letter dated June 14, 2024, in which it
determined that the SIP revision met the completeness criteria in 40
CFR part 51, appendix V.\7\
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\7\ See letter dated June 14, 2024, from Matthew Lakin,
Director, Air and Radiation Division, EPA Region IX, to Karen L.
Peters, Cabinet Executive Officer, ADEQ. CAA sections 110(a) and
110(l) require states to provide reasonable public notice and
opportunity for public hearing prior to the adoption and submission
of a SIP revision to the EPA for evaluation under section 110(k) and
other applicable substantive requirements. To meet this procedural
requirement, a state must include evidence that it provided adequate
public notice and an opportunity for a public hearing, consistent
with the EPA's implementing regulations in 40 CFR 51.102. The EPA
reviewed the information submitted by the ADEQ with the 2023
PM<INF>10</INF> Plan and confirmed the ADEQ's adherence to this
requirement as part of its completeness determination for this SIP
submission.
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The 2023 PM<INF>10</INF> Plan includes Chapter 3, an ``Assessment
of Air Quality Conditions,'' which discusses PM<INF>10</INF> formation
in the West Pinal PM<INF>10</INF> nonattainment area and summarizes the
State's PM<INF>10</INF> precursor evaluation and determination that
precursors do not contribute significantly to PM<INF>10</INF> levels
that exceed the NAAQS in the West Pinal PM<INF>10</INF> nonattainment
area. In addition, Chapter 9 of the 2023 PM<INF>10</INF> Plan, Appendix
A, Exhibit 1, Attachment A, includes a ``Weight of Evidence
Demonstration that Particulate Matter Precursors Do Not Significantly
Contribute to PM-10 Exceedances in the West Pinal County PM-10
Nonattainment Area.''
The information described above that is included in this plan
submittal supplements the information contained in the 2012 NSR SIP
submittal. It also provides a basis on which the EPA may now make the
necessary determination, for purposes of the ADEQ's NNSR program for
PM<INF>10</INF>, pursuant to CAA section 189(e) and 40 CFR
51.165(a)(10). The information allows the EPA to determine whether
major stationary sources and major modifications of PM<INF>10</INF>
precursors contribute significantly to PM<INF>10</INF> levels that
exceed the PM<INF>10</INF> NAAQS in the West Pinal PM<INF>10</INF>
nonattainment area, and therefore must be regulated as part of the
PM<INF>10</INF> NNSR program for West Pinal.
III. Evaluation of PM10 Precursors in the West Pinal PM10 Nonattainment
Area for the ADEQ's NNSR Program Under CAA Section 189(e) and 40 CFR
51.165(a)(10)
A. The EPA's PM10 Precursor Evaluation and Determination
This proposed action is focused on the EPA's determination
concerning whether the ADEQ's NNSR program for PM<INF>10</INF> for the
West Pinal PM<INF>10</INF> nonattainment area satisfies the
requirements of section 189(e) and 40 CFR 51.165(a)(10).
Pursuant to CAA section 189(e) and 40 CFR 51.165(a)(10), for
purposes of the ADEQ's NNSR program regulating PM<INF>10</INF>, the EPA
analyzed whether major stationary sources and major modifications of
PM<INF>10</INF> precursors contribute significantly to PM<INF>10</INF>
levels that exceed the PM<INF>10</INF> NAAQS in the West Pinal
PM<INF>10</INF> nonattainment area. An EPA determination that such
sources and modifications do not contribute significantly means that
the ADEQ's NNSR program for PM<INF>10</INF> for this nonattainment area
is consistent with CAA section 189(e) and 40 CFR 51.165(a)(10) without
regulating PM<INF>10</INF> precursors.
The State's submission provided three lines of evidence to support
its conclusion that PM<INF>10</INF> precursors do not significantly
contribute to PM<INF>10</INF> exceedances in the West Pinal
PM<INF>10</INF> nonattainment area: (1) an evaluation of co-located
PM<INF>2.5</INF>/PM<INF>10</INF> ratios and concentrations on
PM<INF>10</INF> exceedance days in the nonattainment area, (2) a
chemical characterization of coarse and fine fraction particulate
matter in the nonattainment area on PM<INF>10</INF> exceedance days,
and (3) photochemical modeling of the impact of the precursors on
PM<INF>2.5</INF> concentrations in the nonattainment area.
In its analysis of monitoring data from co-located PM<INF>2.5</INF>
and PM<INF>10</INF> monitors, the State examined the ratio of
PM<INF>2.5</INF> to PM<INF>10</INF> concentrations on exceedance days
from 2016 to 2020. Because secondarily formed PM is generally smaller,
falling into the PM<INF>2.5</INF> category, where the ratio of
PM<INF>2.5</INF> to PM<INF>10</INF> is low, this is generally
indicative of wind-blown or other fugitive dust sources. The data in
the submitted analysis show that most exceedance days correspond to low
PM<INF>2.5</INF> to PM<INF>10</INF> ratios, and the State has provided
plausible justifications for those days where the ratio is somewhat
higher.
In its analysis of the chemical characterization of coarse and fine
fraction PM, the State shows that the concentration of secondary
inorganic particulate matter is low, suggesting that ammonia
(NH<INF>3</INF>), sulfur dioxide (SO<INF>2</INF>), and oxides of
nitrogen (NO<INF>X</INF>) are unlikely to contribute to PM<INF>10</INF>
exceedances. The State also analyzed organic aerosols in captured PM
and compared these data to chemically analyzed soil samples, reaching
the conclusion that most of the organic portion of PM<INF>10</INF> was
due to primary emissions. The submitted analysis also suggests that
precursor contributions may have dropped in the last fifteen years, as
activities leading to emissions of precursors in the nonattainment area
have decreased during that time.
In its analysis of photochemical modeling, the State estimated
precursor pollutant contributions to PM<INF>2.5</INF> using the
Comprehensive Air Quality Model with Extensions (CAM<INF>X</INF>)
model. Anthropogenic emissions of NH<INF>3</INF>, NO<INF>X</INF>,
SO<INF>2</INF>, and volatile organic compounds (VOC) from the 2017
National Emissions Inventory were reduced by 70 percent in the modeling
to determine the sensitivity of PM<INF>2.5</INF> concentrations to
these precursor emissions. The modeling results show reduction of 0.5
[micro]g/m\3\ or less when each precursor pollutant was reduced by 70
percent.
The EPA has evaluated the precursor demonstration submitted by the
State and proposes to conclude that these lines of evidence, when taken
together, sufficiently support the conclusion that precursor pollutants
to PM<INF>10</INF> do not significantly contribute to PM<INF>10</INF>
exceedances in the West Pinal PM<INF>10</INF> nonattainment area. Our
Technical Support Document (TSD), which is included in the docket for
this action, provides a more detailed discussion of our analysis
supporting this determination.
B. Determination Regarding the ADEQ's NNSR Program for PM10 in the West
Pinal PM10 Nonattainment Area
As described in section III.A. of this document, the EPA is
proposing to determine that major stationary sources and major
modifications of PM<INF>10</INF> precursors do not contribute
significantly to PM<INF>10</INF> levels that exceed the PM<INF>10</INF>
NAAQS in the West Pinal PM<INF>10</INF> nonattainment area for purposes
of the ADEQ's NNSR program, and therefore the ADEQ's NNSR program for
PM<INF>10</INF> for the West Pinal PM<INF>10</INF> nonattainment area
is consistent with CAA section 189(e) and 40 CFR 51.165(a)(10) without
regulating PM<INF>10</INF> precursors.
As discussed in section I.C. of this document, the EPA has
previously reviewed and fully approved the ADEQ's NNSR program for all
pollutants, including PM<INF>10</INF>, in all areas within the ADEQ's
jurisdiction, with the
[[Page 43983]]
exception of the ADEQ's NNSR program for PM<INF>10</INF> in the West
Pinal PM<INF>10</INF> nonattainment area, for which the EPA issued a
limited approval in its 2015 NSR action specifically based on the need
for the EPA to make a determination regarding the program's consistency
with CAA section 189(e) and 40 CFR 51.165(a)(10) for this area. In
these prior actions on the ADEQ's NSR SIP submittals, the EPA
determined that the ADEQ's NNSR program for PM<INF>10</INF> met all
relevant CAA requirements in all areas, other than the requirements of
CAA section 189(e) and 40 CFR 51.165(a)(10) in the West Pinal
PM<INF>10</INF> nonattainment area.
The EPA's determination in this action that the ADEQ's NNSR program
for PM<INF>10</INF> for the West Pinal PM<INF>10</INF> nonattainment
area is consistent with CAA section 189(e) and 40 CFR 51.165(a)(10)
resolves the issue that led the EPA to issue a limited approval of the
2012 comprehensive NSR submittal for the ADEQ's NNSR program for
PM<INF>10</INF> for the West Pinal PM<INF>10</INF> nonattainment area
in our 2015 NSR action, which is the only remaining issue to be
resolved from the 2012 submittal regarding the full approvability of
the ADEQ's NNSR program for PM<INF>10</INF> in West Pinal. Therefore,
the EPA is now proposing full approval of the ADEQ's NNSR program for
PM<INF>10</INF> for the West Pinal PM<INF>10</INF> nonattainment area
based specifically on our determination that the program is consistent
with the requirements of CAA section 189(e) and 40 CFR 51.165(a)(10).
If finalized, this proposed approval would address the only remaining
element from the 2012 submittal that was not acted upon in the 2015 NSR
action.
IV. Proposed Action
For the reasons discussed in this document, as authorized in
section 110(k)(3) of the Act, the EPA proposes to fully approve the
ADEQ's NNSR program for PM<INF>10</INF> for the West Pinal
PM<INF>10</INF> nonattainment area because we have determined that it
fulfills the relevant CAA requirements. We will accept comments from
the public on this proposal until October 14, 2025, and will consider
those comments before taking final action.
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 Act. Accordingly, this
proposed 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 proposed action:
<bullet> Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Order 12866 (58
FR 51735, October 4, 1993);
<bullet> Is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because SIP actions 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, as 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 proposes to approve a state program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<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 the 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).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Particulate matter, Reporting
and recordkeeping requirements.
Dated: September 3, 2025.
Michael Martucci,
Acting Regional Administrator, Region IX.
[FR Doc. 2025-17502 Filed 9-10-25; 8:45 am]
BILLING CODE 6560-50-P
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</html>Indexed from Federal Register on September 11, 2025.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.