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 November 6, 2020 (85 FR 71023) ^[1] and July 16, 2025 (90 FR 31901) proposed actions. In the November 6, 2020, document we proposed to redesignate the Salt Lake City and Provo 2006 24-hour PM_2.5 NAAs, and to approve multiple related SIP submissions. We proposed approval of the State's January 13, 2020 submittal to revise the SIP based upon revisions to R307-110-10, and the Provo and Salt Lake City 2006 24-hour PM_2.5 maintenance plans and redesignation requests. We also proposed to approve both maintenance plans' 2035 motor vehicle emission budgets (budgets) and the levels of nitrogen oxide (NO_X) and volatile organic compounds (VOC) to direct PM_2.5 budgets trading mechanisms in each maintenance plan. Additionally, the EPA notified the public on October 7, 2025, through EPA's website that we proposed to find the 2035 budgets adequate for transportation conformity purposes.^[2] We proposed approval of these submissions because the Utah Division of Air Quality (UDAQ) adequately addressed all of the requirements of the Act for the SIP revisions and redesignations to attainment applicable to the Provo and Salt Lake City 2006 24-hour PM_2.5 NAAs. We used the 2022-2024 ambient air quality data from the Provo and Salt Lake City NAAs as the basis for our final decision. Upon the effective date of this final action, the designation status of the Provo and Salt Lake City areas under 40 CFR part 81 will be revised to attainment.

Additionally, we proposed to approve SIP revisions submitted on January 19, 2017 (Utah state SIP section IX.H.13) and February 15, 2019 (portions of Utah state SIP section IX.H.11 and 12). We also proposed to approve, through parallel processing, the removal of the startup/shutdown emission limits for the Kennecott Power Plant found in Utah state SIP section IX.H.12.i.i.C, which were formally submitted on October 9, 2020.

The EPA proposed to approve the area sources, major stationary sources, on-road mobile sources, and non-road mobile sources BACM/BACT analyses for the Provo and Salt Lake City 2006 24-hour PM_2.5 NAAs that were submitted on February 4, 2019 and February 15, 2019.

Consistent with the EPA's procedures for parallel processing established under section 2.3 of appendix V to 40 CFR part 51, our July 16, 2025 (90 FR 31901) proposed approval relied upon our evaluation of the public draft version of the revisions to Utah state SIP sections IX.H.11 and 12, R307-110-17, and the revised BACM/BACT analyses for the five sources ^[3] that were adopted by the Utah Air Quality Board on May 7, 2025, and submitted to the EPA on May 20, 2025. UDAQ provided the final submittal to the EPA on July 15, 2025. We have reviewed this submittal and have determined that it does not differ from the public draft version submitted to the EPA on May 20, 2025, that was evaluated for our proposed approval.

II. Response to Comments

During the public notices and comment periods, we received multiple comments that were for and against both proposed actions. The full text of comments received are included in the publicly posted docket associated with this action at https://www.regulations.gov. Our Response to Comments (RTC) document, which is also included in the docket, provides full, detailed responses to all significant comments received and further explains the basis for our final action.

III. Final Action

We are approving the redesignation of the Salt Lake City and Provo 2006 24-hour PM_2.5 NAAs, and the related SIP submissions because UDAQ has adequately addressed all of the requirements of the Act for the SIP revisions and the redesignation to attainment applicable to the Provo and Salt Lake City 2006 24-hour PM_2.5 NAAs.^[4]

We are approving the Governor of Utah's January 13, 2020 submittal, containing revisions to R307-110-10, and the Provo and Salt Lake City 2006 24-hour PM_2.5 maintenance plans and redesignation requests. We are approving both maintenance plans' 2035 budgets. The final 2035 budgets for the Provo NAA are 1.5 tons per day (tpd) direct PM_2.5, 6.5 tpd NO_X, and 7.0 tpd VOCs and the final 2035 budgets for Salt Lake City NAA are 1.38 tpd direct PM_2.5, 21.63 tpd NO_X, and 20.57 tpd VOCs. We also find the budgets adequate, as they meet the adequacy criteria found in the transportation conformity regulation at 40 CFR 93.118(e)(4). The transportation conformity regulation at 40 CFR 93.118(f) sets forth the process by which the EPA reviews adequacy of transportation budgets. In addition, we are approving the NO_X and VOC levels to direct PM_2.5 budgets trading mechanisms in each maintenance plan, as allowed for by the transportation conformity regulation at 40 CFR 93.124(b). Please see the November 6, 2020 proposed rule at 85 FR 71023 for additional information about the trading mechanism and its application in transportation conformity determinations in these areas. We are using 2022-2024 ambient air quality data from the Provo and Salt Lake City NAAs as the basis for our decision. Upon the effective date of this final action, the designation status of the Provo and Salt Lake City areas under 40 CFR part 81 will be revised to attainment.

Additionally, we are approving SIP revisions submitted on January 19, 2017 (Utah state SIP section IX.H.13), and February 15, 2019 (portions of Utah state SIP section IX.H.11 and 12). We are approving the removal of the startup/shutdown emission limits for the Kennecott Power Plant found in Utah state SIP section IX.H.12.i.i.C, which was formally submitted by the State of Utah on December 14, 2020.

The EPA is approving for incorporation into the SIP the area sources, major stationary sources, on-road mobile sources, and non-road mobile sources BACM/BACT analyses for the Provo and Salt Lake City 2006 24-hour PM_2.5 NAAs that were submitted on February 4, 2019 and February 15, 2019.

Additionally, we are approving Utah's July 15, 2020 submission to revise the federally approved Utah state SIP based upon revisions to the Utah state SIP sections IX.H.11 and 12, and the accompanying R307-110-17. Finally, the EPA is approving for incorporation into the federally approved Utah state SIP the five major stationary sources BACM/BACT analyses/updates for the Salt Lake City 2006 24-hour PM_2.5 NAA that were submitted on July 15, 2025.

IV. Incorporation by Reference

In this document, the EPA is finalizing regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR ( printed page 52001) 51.5, the EPA is finalizing the incorporation by reference of: R307-110-10; R307-110-17; Utah state SIP section IX.H.11, 12, and 13; Utah state SIP section IX.A.27 (Provo 2006 24-hour PM_2.5 Maintenance Plan); Utah state SIP section IX.A.36 (Salt Lake City 2006 24-hour PM_2.5 Maintenance Plan); and the redesignation requests for the Provo and Salt Lake City 2006 24-hour PM_2.5 NAAs to attainment. The EPA has made, and will continue to make, these materials generally available through https://www.regulations.gov and at the EPA Region 8 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information). Therefore, these materials have been approved by the EPA for inclusion in the SIP, have been incorporated by reference by the EPA into that plan, are fully federally enforceable under sections 110 and 113 of the CAA as of the effective date of the final rulemaking of the EPA's approval, and will be incorporated by reference in the next update to the SIP compilation.^[5]

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 CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this action:

• Is not a significant regulatory action subject to review by the Office of Management and Budget underExecutive Order 12866 (58 FR 51735, October 4, 1993);
• Is not subject toExecutive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review under Executive Order 12866;
• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
• 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.);
• 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);
• Does not have federalism implications as specified inExecutive Order 13132 (64 FR 43255, August 10, 1999);
• Is not subject toExecutive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;
• Is not a significant regulatory action subject toExecutive Order 13211 (66 FR 28355, May 22, 2001); and
• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA.

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian Tribe has demonstrated that a Tribe has jurisdiction. In those areas of Indian country, the rule does not have Tribal implications and will not impose substantial direct costs on Tribal governments or preempt Tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

This action is subject to the Congressional Review Act (CRA), and the EPA will submit a rule report to each House of the Congress and to the Comptroller General of the United States. This action is not a “major rule” as defined by 5 U.S.C. 804(2).

Under section 307(b)(1) of the CAA, petitions for judicial review of this action must be filed in the United States Court of Appeals for the appropriate circuit by January 20, 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)).

Authority: 42 U.S.C. 7401 et seq.

For the reasons stated in the preamble, the Environmental Protection Agency is amending title 40 CFR parts 52 and 81 as follows:

1. The authority citation for part 52 continues to read as follows:

Authority: 42 U.S.C. 7401 et seq.

2. In § 52.2320:

a. The table in paragraph (c) is amended by revising the entries “R307-110-10” and “R307-110-17”.

b. The table in paragraph (e) is amended by:

i. Under the heading “IX. Control Measures for Area and Point Sources” adding the entries “H.11. General Requirements: Control Measures for Area and Point Sources, Emission Limits and Operating Practices, PM _2.5 ”, “H.12. Source-Specific Emission Limitations in Salt Lake City—UT PM_2.5 Nonattainment Area” in numerical order, and “H.13 Source-Specific Emission Limitations in Provo—UT PM_2.5 Nonattainment Area” after the entry “Section IX.H.4. Interim Emission Limits and Operating Practices” and before the entry “Section IX.H.21. General Requirements: Control Measures for Area and Point Sources, Emission Limits and Operating Practices, Regional Haze Requirements”.

ii. Under the heading “Maintenance Plans” adding the entries “PM_2.5 Maintenance Provisions for the Provo, UT Nonattainment Area” and “PM_2.5 Maintenance Provisions for the Salt Lake City, UT Nonattainment Area” at the end of the section.

The revisions and additions read as follows:

3. The authority citation for part 81 continues to read as follows:

Authority: 42 U.S.C. 7401, et seq.

4. In § 81.345, the table titled “Utah—2006 24-Hour PM _2.5 NAAQS [Primary and Secondary]” is amended by revising the entries “Provo, UT:” and “Salt Lake City, UT:” to read as follows:

90 FR 51999