# Utah.
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Final rule.
**SUMMARY:**
U.S. Environmental Protection Agency (EPA or Agency) is approving a request to expand the boundary for the Northern Wasatch Front (NWF) 2015 8-hour ozone national ambient air quality standard (NAAQS) (2015 ozone 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:**
This rule is effective on February 5, 2026.
**ADDRESSES:**
The EPA has established a docket for this action under Docket ID No. EPA-R08-OAR-2025-0001. All documents in the docket are listed on the *https://www.regulations.gov* 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 *https://www.regulations.gov,* or please contact the person identified in the *FOR FURTHER INFORMATION CONTACT* section for additional availability information.
**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: *[email protected].*
**SUPPLEMENTARY INFORMATION:**
Throughout this document “we,” “us,” and “our” means the EPA.
**I. Background**
The background for this action is discussed in detail in our September 25, 2025 proposal (90 FR 46128). In that document we proposed to approve Utah's boundary expansion request for the NWF 2015 ozone NAAQS NAA under section 107(d)(3)(D) of the CAA, submitted by the State on February 27, 2023, as well as establish a 12-month deadline for State Implementation Plan (SIP) revisions for certain required elements. We received four submittals from five commenters on our proposal and our responses to comments are below.
**II. Response to Comments**
*Comment 1:* One anonymous commenter opposed the action, stating that granting the boundary expansion will result in less protection from air pollution for citizens in Utah.
*Response 1:* The EPA disagrees with the commenter. The purpose of the action is to incorporate additional area into the NAA which includes additional sources that will be held to higher air pollution standards and requirements that all other sources in the same region are required to adhere to. The net benefit is expected to be a reduction in ozone precursors from the US Magnesium, Limited Liability Company (LLC) facility which is located within the NAA due to the finalization of this action.
*Comment 2:* Multiple commenters, including the State of Utah, the Utah Petroleum Association, and the Utah Mining Association, expressed support of the action, including support of the limited revisions of SIP elements and the proposed timeline for submittal.
*Response 2:* The EPA appreciates the State's and industry's support of this action.
*Comment 3:* One commenter claimed that the EPA applied “Administrative Procedure Act (APA) 553(b) good cause provisions” and did not accept public comment before finalizing the rule, resulting in the commenter petitioning the EPA in their comments to stay the effective date of the rule.
*Response 3:* The EPA disagrees with the commenter. This claim relies on commenter's mistaken belief that the EPA issued a final rule with the September 25, 2025 action. The EPA published a notice of proposed rulemaking on September 25, 2025, not a final rule, which included a 30-day public comment period on the proposed rulemaking which closed on October 27, 2025. In this action we are finalizing the September 25, 2025 proposed action. Based on these facts, the proposed rule was not a final action for the commenter to petition the EPA for a stay or delay of a yet-to-be-established effective date. Finally, the EPA is not relying on APA 553(b) in this action.
*Comment 4:* One commenter erroneously claimed that the area was being reclassified from a Serious to a Severe nonattainment area, they stated that 30-50 facilities emitting between 25 and 49 tons per year (tpy) of ozone precursor emissions would become major sources as a result of this action, and argued that the EPA did not provide sufficient analysis on the impact to these small businesses within the NAA.
*Response 4:* The NWF ozone NAA is currently classified as Moderate, and the expanded portion of the NAA will have the same classification. The EPA is not proposing to reclassify the area to a higher classification in this rulemaking, thus the commenter's concern about Severe area SIP requirements becoming newly applicable is erroneous. This commenter also expressed concern about magnitude and types of small businesses that would newly become major sources. This is also incorrect as the major source threshold for Moderate NAAs, which the existing and new portion of the NAA will continue to be classified as, is 100 tpy. The EPA expects only one facility in the new portion of the NAA to be categorized as a major source, US Magnesium, LLC, which is discussed in the proposed rulemaking. [^1] The EPA acknowledges that some confusion may be due to a prior action for the NWF that reclassified the area to Serious, but that rule was stayed by the 10th Circuit Court of Appeals on April 30, 2025, and that rule is currently in abeyance while the EPA reconsiders the action, resulting in the NWF retaining its Moderate classification. [^2]
[^1]*See* 90 FR 46128 (Sept. 25, 2025).
[^2]*See* 89 FR 97545 (Dec. 9, 2024), and *see* 10th Circuit Court of Appeals Decision granting stay motions and staying the Final Rule pending the outcome of these appeals, Appellate Case: 25-9519, dated Apr. 30, 2025.
*Comment 5:* One commenter accused the EPA of not adhering to the following statutory requirements: the Unfunded Mandates Reform Act (UMRA), the Regulatory Flexibility Act/Small Business Regulatory Enforcement Fairness Act (RFA/SBREFA), the Paperwork Reduction Act (PRA), and Executive Order (E.O.) 12866.
*Response 5:* With regard to the UMRA, the EPA has complied by making its own determination that this rule will not result in expenditures of $100M+, and therefore the Agency does not need to complete a statement under 2 U.S.C. 1532. The RFA and SBREFA are inapplicable to this rulemaking because the EPA has certified that this rule will not have a significant economic impact on a substantial number of small entities. The regulatory analysis provisions of the RFA are only triggered by a threshold determination by the Agency that this rule will have a significant economic impact on a substantial number of small entities. Because the Agency has certified this rule will not have a significant economic impact, section 603 and 604 of the RFA do not apply to this rulemaking. 5 U.S.C. 605(b). As discussed in Response 4, this rulemaking is only expected to incorporate one large source into the NAA, US Magnesium, LLC. The EPA has complied with the PRA by certifying in the rule that the PRA does not apply because the action does not involve an information collection burden as defined by the Act. [^3] Lastly, the Agency has complied with E.O. 12866 by determining that this rulemaking is not a significant regulatory action as defined in E.O. 12866.
[^3]*See* 44 U.S.C. 3502(2).
**III. Final Action**
We are approving Utah's boundary expansion request for the NWF 2015 ozone NAAQS NAA under section 107(d)(3)(D) of the CAA. This action will expand the boundary of the existing NWF ozone NAA, adding 12 additional western townships in Tooele County. [^4] The NAA's current classification of Moderate and August 3, 2024 attainment date will apply to the entirety of the newly expanded NWF ozone NAA per 40 CFR 51.1303.
[^4] 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.
As a result of being in nonattainment for ozone, a criteria pollutant, 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, this action is setting a deadline of 12 months from the effective date of this rule (February 5, 2027) for revisions of 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 discussed in detail in our September 25, 2025 proposal and accompanying Technical Support Document (90 FR 46128).
| SIP elements [CAA requirement] | Required to be updated for new portion of NAA? |
| --- | --- |
| Marginal Nonattainment Areas: | |
| Base year emissions inventory [section 172(c)(3); section 182(a)(1); 40 CFR 51.1315(b)] | Yes |
| Certified Nonattainment New Source Review (NNSR) [section 172(c)(5); section 182(a)(4); 40 CFR 51.1314] | No |
| Emissions Statement [section 182(a)(3)(B)] | No |
| Moderate Nonattainment Areas: | |
| Baseline emissions inventory [section 182(b)(1)(B); 40 CFR 51.1310(b)] | Yes |
| 15% Rate of Progress (ROP)/Reasonable Further Progress (RFP) [section 172(c)(2); section 182(b)(1)(A); 40 CFR 51.1310(a)] | Yes |
| Major Source Reasonably Available Control Technology (RACT) for newly designated major sources [section 182(b)(2)(C); 40 CFR 51.1312(b)] | Yes |
| Non-major source Control Techniques Guidelines (CTG) RACT [section 182(b)(2)(A)-(B); 40 CFR 51.1312(a)] | Yes |
| Modeled attainment demonstration [section 182(b)(1); 40 CFR 51.1308(a)-(c)] | No |
| Reasonably Available Control Measures [section 172(c)(1); 40 CFR 51.1308(d); 40 CFR 51.1312(c)] | No |
| Contingency measures [section 172(c)(9)] | No |
| Motor vehicle inspection and maintenance (I/M) program [section 182(b)(4); 40 CFR 51.372(b)(2)] | No |
| Moderate New Source Review (NSR) Offsets [section 182(b)(5)] | No |
**IV. Statutory Authority and Procedural Requirements**
The statutory authority for the requested NAA boundary expansion is provided by the CAA, as amended (42 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.
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.
**V. 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 final 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 the 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 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 the 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.
**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.
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).
The Congressional Review Act (CRA), 5 U.S.C. 801, *et seq.,* as added by the Small Business Regulatory Enforcement Fairness Act of 1996, generally provides that before a rule may take effect, the agency promulgating the rule must submit a rule report, which includes a copy of the rule, to each House of the Congress and to the Comptroller General of the United States. The EPA will submit a report containing this action and other required information to the U.S. Senate, the U.S. House of Representatives, and the Comptroller General of the United States prior to publication of the rule in the *Federal Register* . A major rule cannot take effect until 60 days after it is published in the *Federal Register* . 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 March 9, 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)).
**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: December 16, 2025.
Cyrus M. Western,
Regional Administrator, Region 8.
For the reasons set forth in the preamble, the Environmental Protection Agency is amending 40 CFR part 81 as follows:
**PART 81—DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES**
**40 CFR Part 81**
1. The authority citation for part 81 continues to read as follows:
**Authority:**
42 U.S.C. 7401, *et seq.*
**Subpart C—Section 107 Attainment Status Designations**
**40 CFR Part 81**
2. In § 81.345, in the table “Utah—2015 8-Hour Ozone NAAQS [Primary and Secondary]”, revise the entry “Northern Wasatch Front, UT” to read as follows:
§ 81.345
| Designated area | Designation | Date | Type | Classification | Date | Type |
| --- | --- | --- | --- | --- | --- | --- |
| Northern Wasatch Front, UT | | Nonattainment | February 5, 2026 | Moderate. | | |
| Davis County. | | | | | | |
| Salt Lake County. | | | | | | |
| Tooele County (part): | | | | | | |
| In Tooele County, the following Townships or portions thereof as noted (including Tooele City): | | | | | | |
| Township 1 North Range 6 West. | | | | | | |
| Township 1 North Range 7 West. | | | | | | |
| Township 1 North Range 8 West. | | | | | | |
| Township 2 North Range 6 West. | | | | | | |
| Township 2 North Range 7 West. | | | | | | |
| Township 2 North Range 8 West. | | | | | | |
| Township 3 North Range 7 West. | | | | | | |
| Township 3 North Range 8 West. | | | | | | |
| Township 1 South Range 3 West. | | | | | | |
| Township 1 South Range 4 West. | | | | | | |
| Township 1 South Range 5 West. | | | | | | |
| Township 1 South Range 6 West. | | | | | | |
| Township 1 South Range 7 West. | | | | | | |
| Township 1 South Range 8 West. | | | | | | |
| Township 2 South Range 3 West. | | | | | | |
| Township 2 South Range 4 West. | | | | | | |
| Township 2 South Range 5 West. | | | | | | |
| Township 2 South Range 6 West. | | | | | | |
| Township 2 South Range 7 West. | | | | | | |
| Township 2 South Range 8 West. | | | | | | |
| Township 3 South Range 3 West. | | | | | | |
| Township 3 South Range 4 West. | | | | | | |
| Township 3 South Range 5 West. | | | | | | |
| Township 3 South Range 6 West. | | | | | | |
| Township 3 South Range 7 West. | | | | | | |
| Township 3 South Range 8 West. | | | | | | |
| Township 4 South Range 3 West. | | | | | | |
| Township 4 South Range 4 West. | | | | | | |
| Township 4 South Range 5 West. | | | | | | |
| Township 4 South Range 6 West. | | | | | | |
| All sections within Township 4 South Range 7 West except for section 31. | | | | | | |
| Township 4 South Range 8 West. | | | | | | |
| Weber County (part): | | | | | | |
| All portions of Weber County west of and including Townships 5, 6, and that portion of 7 North Range 1 West that are west of the ridgeline that traces the Wasatch Mountains from the southeast corner of the township to the easternmost extension of the county boundary within the township. | | | | | | |
| | | | | | | |
| * * * * * * * | | | | | | |