Proposed Rule2025-18569
Utah; Northern Wasatch Front; 2015 8-Hour Ozone Nonattainment Area Boundary Expansion and Applicability of Certain Clean Air Act Requirements
Primary source
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Published
September 25, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to approve a request to expand the boundary for the Northern Wasatch Front (NWF) 2015 8-hour ozone national ambient air quality standard (NAAQS) nonattainment area (NAA). The request was submitted by the State of Utah on February 27, 2023. The newly expanded portion of the NWF NAA will have the same classification as the original NWF NAA under the 2015 ozone NAAQS and all applicable Clean Air Act (CAA) requirements will become applicable to the newly designated portion upon the effective date of the final action. The EPA is taking this action pursuant to the CAA.
Full Text
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<title>Federal Register, Volume 90 Issue 184 (Thursday, September 25, 2025)</title>
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[Federal Register Volume 90, Number 184 (Thursday, September 25, 2025)]
[Proposed Rules]
[Pages 46128-46134]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-18569]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 81
[EPA-R08-OAR-2025-0001; FRL-12971-01-R8]
Utah; Northern Wasatch Front; 2015 8-Hour Ozone Nonattainment
Area Boundary Expansion and Applicability of Certain Clean Air Act
Requirements
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve a request to expand the boundary for the Northern Wasatch Front
(NWF) 2015 8-hour ozone national ambient air quality
[[Page 46129]]
standard (NAAQS) nonattainment area (NAA). The request was submitted by
the State of Utah on February 27, 2023. The newly expanded portion of
the NWF NAA will have the same classification as the original NWF NAA
under the 2015 ozone NAAQS and all applicable Clean Air Act (CAA)
requirements will become applicable to the newly designated portion
upon the effective date of the final action. The EPA is taking this
action pursuant to the CAA.
DATES: Written comments must be received on or before October 27, 2025.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2025-0001, to the Federal Rulemaking Portal: <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="https://www.regulations.gov">https://www.regulations.gov</a>. The EPA may publish any comment received
to its public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. The EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e., on the web, cloud, or other file sharing
system). For additional submission methods, the full EPA public comment
policy, information about CBI or multimedia submissions, and general
guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
Docket: All documents in the docket are listed in the <a href="https://www.regulations.gov">https://www.regulations.gov</a> index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available electronically in
<a href="https://www.regulations.gov">https://www.regulations.gov</a>. Please email or call the person listed in
the FOR FURTHER INFORMATION CONTACT section if you need to make
alternative arrangements for access to the docket.
FOR FURTHER INFORMATION CONTACT: Amanda Brimmer, Air and Radiation
Division, EPA, Region 8, Mailcode 8ARD-AQ-R, 1595 Wynkoop Street,
Denver, Colorado 80202-1129, telephone number: (303) 312-6323, email
address: <a href="/cdn-cgi/l/email-protection#fb99899296969e89d59a969a959f9abb9e8b9ad59c948d"><span class="__cf_email__" data-cfemail="4c2e3e252121293e622d212d22282d0c293c2d622b233a">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' or ``our'' is used, we mean the EPA.
I. Background
On October 26, 2015, the EPA revised the national standards for
ground-level ozone, promulgating identical primary and secondary ozone
standards that specified an 8-hour ozone level of 0.070 parts per
million (ppm).\1\ In a separate action, the EPA assigned classification
thresholds and attainment dates based on each NAA's monitored ozone
levels.\2\ Consistent with CAA section 181(a), the EPA established
attainment dates based on nonattainment classification; with the
attainment date for Marginal areas as August 3, 2021 and Moderate areas
as August 3, 2024.
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\1\ National Ambient Air Quality Standards for Ozone, 80 FR
65452 (Oct. 26, 2015).
\2\ See 83 FR 10376 (May 8, 2018).
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Upon promulgation of the revised 2015 ozone NAAQS, the State of
Utah submitted initial designations to the EPA based on monitored air
quality data from 2013-2015 and recommended that Salt Lake and Davis
Counties, and portions of Weber and Tooele Counties be designated as
nonattainment. The EPA did not modify the State's initial designation
and, effective August 3, 2018, the EPA designated the NWF as a Marginal
NAA.\3\
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\3\ See 83 FR 25776 (Jun. 4, 2018), including Docket ID No.`EPA-
HQ-OAR-2017-0548-0148', titled, ``EPA's preliminary response to
Utah's recommendations and information about EPA's approach for
completing designations for the revised ozone standards''.
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On October 7, 2022, the EPA determined that the NWF did not attain
the NAAQS by the Marginal attainment date, and the area was
subsequently reclassified by operation of law to a Moderate NAA.\4\ A
State Implementation Plan (SIP) outlines how states will implement
controls to satisfy statutory and regulatory requirements under the
2015 ozone NAAQS and demonstrate how the area will attain the ozone
standard by the attainment date. The submission deadline for a majority
of the required ozone SIP elements was established as January 1, 2023
for Moderate ozone NAA's. The EPA's implementing regulations at 40 Code
of Federal Regulations (CFR) 51.1308-51.1315 address ozone SIP
requirements including attainment demonstrations, Reasonable Further
Progress (RFP) and associated milestone demonstrations, reasonably
available control technology (RACT), reasonably available control
measures (RACM), major nonattainment new source review, emission
inventories, the timing of required SIP submissions, and compliance
with emission control measures in the SIP.
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\4\ See 87 FR 60897 (Oct. 7, 2022).
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In 2020 and 2021, the State of Utah submitted Marginal SIP elements
to the EPA, which were approved in 2021 and 2022 respectively.\5\ On
December 12, 2024, Utah submitted a Moderate ozone SIP to meet CAA
section 182(b) and which was deemed complete by operation of law on
June 12, 2025.\6\ The EPA is currently reviewing the submitted Moderate
SIP elements and will be acting on them in future actions.
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\5\ See 86 FR 35405 (Jul. 6, 2021) and 87 FR 24275 (Apr. 25,
2022).
\6\ 40 CFR part 51, appendix V, section 1.1.2.
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In December 2024, the NWF NAA was reclassified to Serious by
operation of law due to an EPA finding of failure to attain by the
Moderate attainment date. That action reclassified the area to Serious
by operation of law with an effective date of January 8, 2025.\7\
However, the Final Rule was stayed by the 10th Circuit Court of Appeals
in April 2025 due to petitions for review that were filed by the State
of Utah and the Utah Petroleum Association (UPA) and the EPA is
currently in the process of reconsidering the final action.\8\ The
practical implication of this judicial stay is that the NWF NAA is
currently classified as Moderate as of the date of this proposal. The
stay will be lifted pending EPA concluding its reconsideration. In the
event the classification of Serious is retained, the NWF would again be
subject to Serious Area planning requirements consistent with CAA
section 182(c). The classification and applicable requirements for the
current NAA will also apply to the newly redesignated area, if this
proposal is finalized.
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\7\ See 89 FR 97545 (Dec. 9, 2024).
\8\ See State of Utah and UPA v. U.S. Environmental Protection
Agency, No. 25-9519 (10th Cir. 2025).
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II. Utah's Submittal
The State's modeling efforts associated with the Moderate SIP
development for the 2015 ozone NAAQS showed that large amounts of
nitrogen oxides (NO<INF>X</INF>) and volatile organic compound (VOC)
emissions from a source located upwind of the NAA, namely US Magnesium
LLC (US Magnesium), was directly impacting high ozone levels within the
NWF NAA. Located in Tooele County on the southwestern edge of the Great
Salt Lake, US Magnesium has significant amounts of precursor emissions
that contribute to both ozone and fine
[[Page 46130]]
particulate matter (PM<INF>2.5</INF>) formation along the Wasatch Front
in addition to also producing halogen emissions which further increase
ozone formation.\9\
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\9\ See UDAQ, Supporting Documentation, Request for Adjustment
of the Northern Wasatch Front Nonattainment Area Boundary for the
2015 8-hour Ozone National Ambient Air Quality Standard, Feb. 27,
2023.
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On February 27, 2023, the State of Utah submitted a request to the
EPA to expand the NAA boundary of the NWF to include the US Magnesium
facility.\10\ US Magnesium was initially omitted from the NWF NAA based
on the State's recommendation that the ozone nonattainment boundary be
identical to the 2006 24-hour PM<INF>2.5</INF> nonattainment boundary
for Davis, Salt Lake, Tooele, and Weber Counties.\11\ This
recommendation was based on assessing the impact of emissions during
the winter months since that is when the Salt Lake City region tends to
experience PM<INF>2.5</INF> exceedances. As detailed in the State's
2023 boundary expansion request and associated analysis, this point
source has likely been contributing to elevated ozone levels in the
NWF.\12\ The State determined that tighter emission controls on its
highest emitting units will benefit the NWF and therefore submitted to
the EPA the NAA boundary expansion request.\13\
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\10\ See letter dated Feb. 27, 2023 from Utah Governor Spencer
Cox to EPA R8 Administrator KC Becker and see accompanying
attachment titled, ``Request for Adjustment of the Northern Wasatch
Front Nonattainment Area Boundary for the 2015 8-hour Ozone National
Ambient Air Quality Standard''.
\11\ Utah, Area Designation Recommendation for the 2006
PM<INF>2.5</INF> NAAQS, Dec. 18, 2007, <a href="https://www3.epa.gov/pmdesignations/2006standards/rec/letters/08_UT_rec_a1.pdf">https://www3.epa.gov/pmdesignations/2006standards/rec/letters/08_UT_rec_a1.pdf</a>, pg. 30.
\12\ See Footnote # 9.
\13\ See Footnote # 9, pg. 5.
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III. EPA Evaluation
When the Governor of any State, on the Governor's own motion,
submits a revised designation of areas in the state designated as
nonattainment, attainment, or unclassifiable, the Administrator shall
act on such designations in accordance with the procedures under
section 107(d)(3)(D). In its request to expand the boundary of the NWF,
the State of Utah conducted a five-factor analysis, which evaluated
emissions, air quality data, meteorology, jurisdictional boundaries,
and geography/topography. This analysis concluded that, ``emissions
from US Magnesium extend to nearly the entire Wasatch Front with plumes
emitted from the plant observed across a wide sector of the populated
regions of the valleys, and that secondary chemistry from these plumes
result in a 10-20% increase in PM<INF>2.5</INF> in the urban regions of
the valleys as well as an increase of up to 10% in ozone formation due
to the production of additional oxidants.'' \14\ Additionally,
preliminary modeling by the State of Utah found increases in summertime
ozone concentrations at a number of monitoring sites in the NAA
downwind of US Magnesium due to halogens emissions, which, ``clearly
show that uncontrolled emissions from within the proposed new boundary
are regularly transported to the current NAA, and directly contribute
to the area's air quality challenges''.\15\
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\14\ See Footnote # 9, pg. 5.
\15\ See Footnote # 9, pg. 5, and appendix B, Environ. Sci.
Technol. 2023, 57, 5, 1870-1881, Carrie Womack, Wyndom Chace, Siyuan
Wang, Munkh Baasandorj, Dorothy Fibiger, Lexie Goldberger, Ben Lee,
Colin Harkins, Duseong Jo, John Lin, Brian McDonald, Erin McDuffie,
Ale Franchin, Ann Middlebrook, Alexander Moravek, Jennifer Murphy,
J. Andrew Neuman, Joel Thornton, Patrick Veres, Steve Brown; Mid-
latitude ozone depletion and air quality impacts from industrial
halogen emissions: aircraft measurements in the Great Salt Lake
Basin (2022), <a href="https://doi.org/10.1021/acs.est.2c05376">https://doi.org/10.1021/acs.est.2c05376</a>. Halogens were
measured as part of a 4-week ground- and aircraft-based field
intensive aircraft measurement campaign in Salt Lake City, Utah in
2017.
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The EPA supports the State's conclusion and concurs with the
State's request to include additional townships and US Magnesium within
the NWF ozone NAA for the 2015 ozone NAAQS. Utah's full technical
analysis is provided in Utah's supporting documentation titled,
``Request for Adjustment of the Northern Wasatch Front Nonattainment
Area Boundary for the 2015 8-hour Ozone National Ambient Air Quality
Standard''. The EPA's review supporting our proposed action is
discussed in an accompanying Technical Support Document (TSD).\16\ Both
documents are available in the docket for this action (see <a href="https://www.regulations.gov">https://www.regulations.gov</a>, Docket ID No. EPA-R08-OAR-2025-0001).
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\16\ EPA, TSD, NWF, Utah: Air Quality State Implementation
Plans; Approvals and Promulgations; 2015 8-Hour Ozone Nonattainment
Area Requirements; Boundary Expansion; Determination Regarding
Applicability of Certain Clean Air Act Requirements.
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IV. Proposed Action
The EPA is proposing to approve Utah's boundary expansion request
for the NWF 2015 8-hour ozone NAAQS NAA under section 107(d)(3)(D) of
the CAA. The request was submitted on February 27, 2023. This proposed
action will expand the boundary of the existing Moderate NAA and does
not create any new NAA's. Upon finalization of this rule, the Moderate
area classification and August 3, 2024 attainment date will apply to
the entirety of the newly expanded NWF Moderate NAA per 40 CFR 51.1303.
Specifically, the State is requesting to add 12 additional western
townships in Tooele County into the ozone NAA.\17\ Upon the effective
date of the boundary expansion, source emissions from these new
townships within the NAA, including from US Magnesium, will need to be
included in a revised 2017 base year emissions inventory. Emission
reductions that occurred after the 2017 base year, and that are the
result of federally enforceable controls, can be credited in the
State's Moderate ozone SIP. US Magnesium, and any other sources that
are determined to be major stationary sources based on the area's
nonattainment classification and annual emissions of NO<INF>X</INF>
and/or VOC, will be required to apply for a CAA Title V permit, conduct
a RACT analysis, and adhere to applicable New Source Review
offsets.\18\ More information on the initial designation process for
PM<INF>2.5</INF> and ozone is discussed in the accompanying TSD for
this proposal.
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\17\ Specifically, this will include Townships 1 North Range 6-8
West, Townships 2 North Range 6-8 West, Townships 3 North Range 7-8
West, and Townships 1-4 South Range 8 West. Further, EPA is
correcting an error related to Township 4 South Range 7 West. This
should read, ``All sections within Township 4 South Range 7 West
except for section 31'', as first divisions 29, 30, and 32 do not
exist in this Township and first division 31 continues to be omitted
from the NWF ozone NAA due to being Indian Country.
\18\ See CAA section 172(c)(5), CAA section 182(b)(2), and
appendix S to part 51, Title 40--Emission Offset Interpretative
Ruling. Specifically, Title V permits are requirements under the CAA
for all large sources (``major'' sources) and a limited number of
smaller sources (called ``area'' sources, ``minor'' sources, or
``non-major'' sources). These permits are legally-enforceable
documents that include pollution control requirements from federal
or state regulations that apply to a source. Most are issued by
state or local agencies (``Clean Air Act part 70'' permits); a small
number are issued by the EPA (``Clean Air Act part 71'' permits).
Most are issued by state or local agencies (``Clean Air Act part
70'' permits); a small number are issued by the EPA (``Clean Air Act
part 71'' permits).
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As a result of being in nonattainment for a criteria pollutant,
including ozone, the CAA requires specific elements be developed and
submitted to the EPA for approval. Deadlines for ozone SIP elements are
set forth in 40 CFR 51.1402. To satisfy CAA requirements for the
requested new portion of the NAA, the EPA is proposing to require
revisions for certain Marginal and Moderate SIP elements as outlined in
table 1. A detailed discussion and rationale for the proposed Marginal
and Moderate area SIP revisions is below, including discussion about
each element, what is required, and the EPA's rationale for proposing
whether to require the State to update each element to reflect the new
portion of the
[[Page 46131]]
NAA. The elements proposed to be resubmitted are based on the EPA's
determination of whether the addition of new territory to the NAA would
have any impact on already submitted Marginal and Moderate SIP
elements. Some elements do not need resubmission as the elements are
not affected by the inclusion of new sources in the expanded NAA
boundary area. Elements such as emissions inventories and the
implementation of reasonably available control technologies will need
to be resubmitted to include new sources in the expanded NAA boundary
area and are therefore required to be addressed for the new portion of
the NAA. The EPA's proposal to require revisions for some, but not all
submitted SIP elements is not an indication of the EPA's determination
of approvability of said elements or the Agency's intention to approve
or disapprove any specific element. Approval of submitted Moderate SIP
elements for the NWF will be addressed in future Federal Register
documents and actions.
Given the deadlines for Marginal and Moderate SIP elements are
years in the past, EPA is proposing to set the deadline for applicable
Marginal and Moderate SIP revisions for the new portion of the NAA as
12 months after the effective date of this rule but are taking comments
on an alternative timeline.
Table 1--Required Marginal and Moderate SIP Elements
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Required to be
SIP elements [CAA requirement] updated for new
portion of NAA?
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Marginal Nonattainment Areas:
Base year emissions inventory [section Yes \1\
172(c)(3); section 182(a)(1); 40 CFR
51.1315(b)]....................................
Certified Nonattainment New Source Review (NNSR) No \2\
[section 172(c)(5); section 182(a)(4); 40 CFR
51.1314].......................................
Emissions Statement [section 182(a)(3)(B)]...... No \2\
Moderate Nonattainment Areas:
Baseline emissions inventory [section Yes
182(b)(1)(B); 40 CFR 51.1310(b)]...............
15% Rate of Progress (ROP)/Reasonable Further Yes
Progress (RFP) [section 172(c)(2); section
182(b)(1)(A); 40 CFR 51.1310(a)]...............
Major Source Reasonably Available Control Yes
Technology (RACT) for newly designated major
sources [section 182(b)(2)(C); 40 CFR
51.1312(b)]....................................
Non-major source Control Techniques Guidelines Yes
(CTG) RACT [section 182(b)(2)(A)-(B); 40 CFR
51.1312(a)]....................................
Modeled attainment demonstration [section No
182(b)(1); 40 CFR 51.1308(a)-(c)]..............
Reasonably Available Control Measures [section No
172(c)(1); 40 CFR 51.1308(d); 40 CFR
51.1312(c)]....................................
Contingency measures [section 172(c)(9)]........ No
Motor vehicle inspection and maintenance (I/M) No
program [section 182(b)(4); 40 CFR
51.372(b)(2)]..................................
Moderate New Source Review (NSR) Offsets No \2\
[section 182(b)(5)]............................
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\1\ See 86 FR 35405 (Jul. 6, 2021).
\2\ See 87 FR 24275 (Apr. 25, 2022).
A. Marginal Area SIP Elements
1. Element Needing Updates Due to Revised NAA Boundary
Base Year Emissions Inventory
The State of Utah was required to submit a 2017 base year inventory
as defined by Sec. 51.1300(p), to meet the emissions inventory
requirement of CAA section 182(a)(1), no later than 24 months after the
effective date of designation. The State met this requirement for the
initial Marginal NAA, which was approved by the EPA July 2021.\19\ As
proposed, for the expanded area, the State will need to, submit a
revised comprehensive, accurate, 2017 base year inventory of actual
emissions from all sources of the relevant pollutants to include
additional NO<INF>X</INF> and VOC emissions for the new portion of the
NAA.\20\ The EPA is proposing that this element be due 12 months from
the effective date of the final rule expanding the NWF NAA.
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\19\ See 86 FR 35405.
\20\ See 40 CFR part 51, subpart A.
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2. Elements Not Needing Updates Due to Revised NAA Boundary
a. Certified NNSR
The State of Utah was required to submit a NNSR plan no later than
36 months after the effective date of the area's designation of
nonattainment for the 2015 ozone NAAQS. The State's NNSR plan requires
permits for the construction and operation of new or modified major
stationary sources anywhere in the NAA, and sets emission offset
thresholds in accordance with 40 CFR 51.1314. The State met this
requirement for the initial Marginal NAA, which was approved by the EPA
April 2022.\21\ As proposed, this requirement will not need to be
resubmitted as the approved State regulation applies to all NAA's and
classifications and will therefore apply to the new portion of the
boundary upon finalization of the expansion.
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\21\ See 87 FR 24275.
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b. Emissions Statement Rule
The State of Utah was required to implement an emissions statement
rule in its Marginal NAA's that requires the owner or operator of each
stationary source of NO<INF>X</INF> or VOCs to provide the State with
an annual statement showing the actual emissions from the source.\22\
The State met this requirement, which was approved by the EPA April
2022.\23\ As proposed, this requirement will not need to be resubmitted
as the approved State regulation applies to all NAA's and will
therefore apply to the new portion of the boundary upon finalization of
the expansion.
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\22\ See 87 FR 24275.
\23\ See 87 FR 24275.
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B. Moderate Area SIP Elements
1. Elements Needing Updates Due to Revised NAA Boundary
a. Baseline Emissions Inventory for Reasonable Further Progress Plans
For Moderate ozone NAA's, a baseline emissions inventory is
required to be submitted to the EPA, under the provisions of the Air
Emissions Reporting Rule (AERR), to demonstrate compliance with the
ROP/RFP requirement (see section IV.B.1.b below).\24\ The emission
values included in the inventory required by this section shall be
actual ozone season day
[[Page 46132]]
emissions as defined by Sec. 51.1300(q). The State submitted a SIP
revision in 2024 to meet this requirement for the original Moderate
NAA. However, as proposed, for the expanded area, the State will need
to submit a revised, comprehensive, accurate, 2017 base year inventory
of actual emissions from all sources of the relevant pollutants to
include additional NO<INF>X</INF> and VOC emissions for the new portion
of the NAA. It is presumed that this element can be submitted for
purposes of meeting both this requirement and the revised 2017 base
year emissions inventory requirement (see section IV.A.1 above). The
EPA is proposing that this element be due 12 months from the effective
date of the final rule expanding the NWF NAA.
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\24\ See Footnote # 20.
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b. 15% ROP/RFP
Per CAA section 182(b)(1)(A)(i) and 40 CFR 51.1310(a)(4), under the
2015 ozone NAAQS, Moderate NAA's must show a 15% reduction in emissions
in 6 years starting from a 2017 base year through the 2023 Moderate
area attainment year. The State submitted a SIP revision in 2024 to
meet this requirement for the original Moderate NAA. However, as
proposed, the State will need to submit a revised ROP plan to the EPA
due to an adjusted base year inventory as well as to take SIP credit
for emission reductions from SIP measures implemented in the newly
expanded area. The EPA is proposing that this element be due 12 months
from the effective date of the final rule expanding the NWF NAA.
c. RACT for Newly Designated Major Sources
For purposes of determining whether a source is a major stationary
source as defined in CAA section 182(b)(2) and section 182(f), the
amount of VOC and NO<INF>X</INF> emissions are to be considered
separately.\25\ For the NWF NAA, Utah submitted a SIP revision in 2024
to meet this requirement for the original Moderate NAA. However, Utah
has identified one stationary source, US Magnesium, that will become a
major source for NO<INF>X</INF> and VOC as part of the boundary request
and Utah will need to complete a RACT analysis for this source. Utah
will also need to determine if any other sources in the new portion of
the NAA exceed the Moderate NAA threshold for major sources, and
conduct a RACT analysis if any are identified. The CAA requires that
RACT be implemented as expeditiously as practicable, but no later than
January 1 of the fifth year after the effective date of
designation.\26\ Given that this date is now in the past, the EPA is
proposing that implementation of RACT for newly determined major
sources under 40 CFR 51.1312(b) be due 12 months from the effective
date of the final rule expanding the NWF NAA.
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\25\ Per CAA section 302(j)/42 U.S.C. 7602(j), '' Except as
otherwise expressly provided, the terms ``major stationary source''
and ``major emitting facility'' mean any stationary facility or
source of air pollutants which directly emits, or has the potential
to emit, one hundred tons per year or more of any air pollutant
(including any major emitting facility or source of fugitive
emissions of any such pollutant, as determined by rule by the
Administrator).''
\26\ See 83 FR 25776.
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d. Non-Major Source CTG RACT
CTG RACT is required for Moderate and above ozone NAA's. The State
submitted a SIP revision in 2024 to meet this requirement for the
original Moderate NAA. However, as proposed, the State will need to
reevaluate all CTGs for which it submitted a negative declaration and
either reconfirm that CTGs listed are still accurate for the expanded
NWF NAA or provide analysis for any emission sources in the newly added
area that are subject to a CTG that was previously on the negative
declarations list. Per 40 CFR 51.1312(a)(3)(iii), Utah shall provide
for implementation of CTG RACT as expeditiously as practicable, but no
later than January 1 of the third year after the associated SIP
submission deadline or the deadline established by the Administrator in
the final action issuing the CTG. Given both dates are now in the past,
the EPA is proposing that the deadline for implementation of CTG RACT
for sources located within the new portion of the NWF NAA be 12 months
from the effective date of the final rule expanding the NWF NAA.
2. Elements Not Needing Updates Due to Revised NAA Boundary
a. Modeled Attainment Demonstration
The State of Utah was required to submit an attainment
demonstration that provides for reductions in emissions of VOCs and
NO<INF>X</INF> as necessary to attain the 2015 ozone NAAQS by the
Moderate area attainment date of August 3, 2024.\27\ The State
submitted a SIP revision in 2024 to meet this requirement for the
original Moderate NAA. Due to the Moderate attainment date being in the
past, the EPA does not see a rational need for a revised modeled
attainment demonstration. This is because emissions from the new area
were already included in the regional modeling domain and would not
change the outcome regarding whether the area was able to model
attainment for the 2023 ozone season. Therefore, the EPA is proposing
that this Moderate area SIP element does not need to be revised and
resubmitted for the NWF NAA.
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\27\ See 40 CFR 51.1308(a).
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b. RACM
For each NAA required to submit an attainment demonstration under
40 CFR 51.1308(a) and (b), Utah needs to submit a SIP revision
demonstrating that it has adopted all RACM necessary to demonstrate
attainment as expeditiously as practicable and to meet any RFP
requirements.\28\ The goal of this SIP requirement is to identify
feasible control measures that will advance attainment.\29\ Utah
submitted a SIP revision in 2024 to meet this requirement for the
original Moderate NAA. Similar to the rationale given for the modeled
attainment demonstration in section IV.B.2.a above, since the Moderate
attainment date is in the past, requiring the State to submit a RACM
analysis for the new portion of the NAA to demonstrate whether any new
strategies could advance attainment by one year (i.e., by summer 2022)
is illogical and impossible. Therefore, the EPA is proposing that this
Moderate area SIP element does not be revised and resubmitted for the
NWF NAA.
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\28\ See 40 CFR 51.1308(d).
\29\ See 40 CFR 51.1312(c).
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c. Contingency Measures
This element is required under CAA section 172(c)(9) and is
intended to provide for the implementation of specific measures to be
undertaken if the area fails to make ROP/RFP or to attain the NAAQS by
the attainment date. Such measures shall be included in the plan
revision as contingency measures to take effect in any such case
without further action by the State or the Administrator. The State
submitted a SIP revision in 2024 to meet this requirement. Since
contingency measures only need apply ``within'' the NAA, the EPA is
proposing that this Moderate area SIP element does not be revised and
resubmitted for the NWF NAA.
d. Motor Vehicle I/M Program
I/M programs are required for certain urbanized NAA's classified as
Moderate and above based on criteria detailed in the CAA and the
federal I/M rule at 40 CFR part 51, subpart S. The CAA establishes two
performance levels of I/M programs: ``Basic'' and ``Enhanced'' I/M.
Moderate ozone NAA's are to implement Basic I/M in any 1990 Census-
defined urbanized areas with a population of 200,000 or more. The
[[Page 46133]]
State submitted a SIP revision in 2024 to meet this requirement and as
a Moderate ozone NAA, the NWF is currently operating Basic I/M programs
in all areas that meet the urbanized population criteria.
Pursuant to 40 CFR 51.350(a)(6), if the boundaries of a Moderate
ozone NAA are changed, Basic I/M shall be implemented in any additional
urbanized areas with a population of 200,000 or more. Since the new
territory being proposed for addition to the NWF NAA is rural (and
below the population threshold), the EPA is proposing that this
Moderate area SIP element does not be revised and resubmitted for the
NWF NAA.\30\
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\30\ Based on the 2020 United State Census, Tooele County's
population is 72,700, with 200 people (or 0.2% of the total
population) being added to the NWF ozone NAA. Source: ArcGIS--U.S.
Census Bureau, <a href="https://services.arcgis.com/P3ePLMYs2RVChkJx/arcgis/rest/services/USA_Census_Populated_Places/FeatureServer">https://services.arcgis.com/P3ePLMYs2RVChkJx/arcgis/rest/services/USA_Census_Populated_Places/FeatureServer</a>, accessed 8/
12/25.
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e. NSR Offsets
For purposes of satisfying the emission offset requirements of CAA
section 182(b)(5), the ratio of total emission reductions of VOCs to
total increased emissions of such air pollutant shall be at least 1.15
to 1 for Moderate NAA's. The State's Marginal SIP submittal
demonstrated that this requirement is being met and will continue to be
met for all possible NAA's and classifications were this area or any
new area to be reclassified to a higher classification in the
future.\31\ The EPA approved regulation applies to any and all current
and future ozone NAA's, including the new portion of the boundary upon
finalization of the expansion. Therefore, the EPA is proposing that
this Moderate area SIP element does not be revised and resubmitted for
the NWF NAA.
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\31\ See 87 FR 24275. This SIP element was approved by EPA in
April 2022.
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V. Statutory Authority and Procedural Requirements
State of Utah, section 19-2-104 of the Utah Code gives the Utah Air
Quality Board the authority to promulgate rules ``regarding the
control, abatement, and prevention of air pollution from all sources
and the establishment of the maximum quantity of air pollutants that
may be emitted by an air pollutant source.'' The Utah Division of Air
Quality (UDAQ) develops, prepares, and submits SIPs to the Utah Air
Quality Board for consideration and promulgation. UDAQ is the primary
State agency responsible for the development and implementation of SIPs
once they are approved by the Utah Air Quality Board, and associated
administrative rules, as required by the CAA.
The statutory authority for the requested NAA boundary expansion is
provided by the CAA, as amended (42 United States Code (U.S.C.) 7401,
et seq.). For areas seeking to change the boundary of an already
designated NAA, CAA section 107(d)(3)(D) states, ``The Governor of any
state may, on the Governor's own motion, submit to the Administrator a
revised designation of any area or portion thereof within the State.
Within 18 months of receipt of a complete state redesignation
submittal, the Administrator shall approve or deny such redesignation.
The submission of a redesignation by a Governor shall not affect the
effectiveness or enforceability of the applicable implementation plan
for the State.'' The State was not required to take public comment on
the requested boundary expansion.
The EPA is soliciting public comments on the issues discussed in
this proposed rule (see DATES section). We will accept comments from
the public on this proposal for the next 30 days and will consider
comments before taking final action. CAA section 107(d)(1)(B)(ii) lays
out a particular process when the EPA disagrees with a state's
recommended designations. Because the EPA is agreeing with the State of
Utah's recommended boundary expansion and is proposing to approve the
State's request, the EPA did not send a 120-day letter to the State
prior to this proposed action. Under CAA section 107(d)(2)(B), the EPA
is not required to provide an Administrative Procedure Act public
comment period for designation actions, however, public comment is
being accepted as part of this proposal.
VI. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
This action is not a significant regulatory action as defined in
Executive Order 12866 and was therefore not subject to a requirement
for Executive Order 12866 review.
B. Executive Order 14192: Unleashing Prosperity Through Deregulation
This action is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because NAA boundary revision actions under the CAA
are exempt from review under Executive Order 12866.
C. Paperwork Reduction Act
This proposed rule does not impose an information collection burden
under the provisions of the Paperwork Reduction Act of 1995 (44 U.S.C.
3501 et seq.).
D. Regulatory Flexibility Act
This action merely approves state law as meeting Federal
requirements and imposes no additional requirements beyond those
imposed by state law. Accordingly, the Administrator certifies that
this rule will not have a significant economic impact on a substantial
number of small entities under the Regulatory Flexibility Act (5 U.S.C.
601 et seq.).
E. 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.
F. 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.
G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
Executive Order 13175 (65 FR 67249, November 9, 2000), requires EPA
to develop an accountable process to ensure ``meaningful and timely
input by Tribal officials in the development of regulatory policies
that have Tribal implications.'' This proposed rule does not have
Tribal implications, as specified in Executive Order 13175. It will not
have substantial direct effects on Tribal governments. Thus, Executive
Order 13175 does not apply to this rule.
H. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks
This action is not subject to Executive Order 13045 because it is
not 3(f)(1) significant as defined in Executive Order 12866, and
because EPA does not believe the environmental health or safety risks
addressed by this action present a disproportionate risk to children
because it approves a state program.
[[Page 46134]]
I. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use
This action is not subject to Executive Order 13211 (66 FR 28355
(May 22, 2001)), because it is not a significant regulatory action
under Executive Order 12866.
J. National Technology Transfer Advancement Act
This rulemaking does not involve technical standards.
List of Subjects in 40 CFR Part 81
Environmental protection, Administrative practice and procedure,
Air pollution control, Designations and classifications,
Intergovernmental relations, Nitrogen oxides, Ozone, Reporting and
recordkeeping requirements, Volatile organic compounds.
Authority: 42 U.S.C. 7401, et seq.
Dated: September 16, 2025.
Cyrus M. Western,
Regional Administrator, Region 8.
[FR Doc. 2025-18569 Filed 9-24-25; 8:45 am]
BILLING CODE 6560-50-P
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</html>Indexed from Federal Register on September 25, 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.