SUPPLEMENTARY INFORMATION:

Organization of this document. Throughout this document the use of “we,” “us,” or “our” is intended to refer to the EPA. The information in this preamble is organized as follows:

Table of Contents

I. Background

II. Legal Authority

III. Proposed Action

IV. Tribal Consultation

V. Statutory and Executive Order Reviews

I. Background

Ground-level ozone pollution is formed from the reaction of volatile organic compounds (VOC) and nitrogen oxides (NO_X ) in the presence of sunlight. These two pollutants, referred to as ozone precursors, are emitted by many types of sources, including on-road and non-road motor vehicles and engines, industrial facilities, and smaller area sources such as lawn and garden equipment and paints. Scientific evidence indicates that adverse public health effects occur following exposure to ground-level ozone pollution.^[1] Exposure to ozone can harm the respiratory system (the upper airways and lungs), can aggravate asthma and other lung diseases, and is linked to premature death from respiratory causes. People most at risk from breathing air containing ozone include people with asthma, children, older adults, and people who are active outdoors, especially outdoor workers.^[2]

Under CAA section 109, the EPA promulgates NAAQS (or “standards”) for “each air pollutant for which air quality criteria have been issued. . . .”, such as ozone.^[3] The EPA has previously promulgated NAAQS for ozone in 1979, 1997, and 2008.^[4] On October 26, 2015, the EPA revised the NAAQS for ozone to establish new 8-hour standards.^[5] In that action, the EPA promulgated identical revised primary and secondary ozone standards designed to protect public health and welfare that specified an 8-hour ozone level of 0.070 parts per million (ppm).^[6] Specifically, the standards require that the 3-year average of the annual fourth highest daily maximum 8-hour average ozone concentration ( i.e., the design value (DV)) may not exceed 0.070 ppm.^[7] Further, while the ozone NAAQS is expressed in units of ppm, ozone is also discussed in terms of parts per billion (ppb), with 0.001 ppm equaling 1 ppb.^[8]

Section 107(d) of the CAA provides that when the EPA promulgates a new or revised NAAQS, the Agency must designate areas of the country as nonattainment, attainment, or unclassifiable based on whether an area is not meeting (or is contributing to air quality in a nearby area that is not meeting) the NAAQS, meeting the NAAQS, or cannot be classified as meeting or not meeting the NAAQS, respectively.^[9] Subpart 2 of Part D of Title I of the CAA governs the classification, state planning, and emission control requirements for any ( printed page 21755) areas designated as nonattainment for a revised primary ozone NAAQS. In particular, CAA section 181(a)(1) also requires the EPA to classify each ozone NAA at the time of designation, based on the extent of the ozone problem in the area (based on the area's DV).^[10] Classifications for ozone NAAs range from Marginal to Extreme. CAA section 182 provides the specific attainment planning requirements that apply to each ozone NAA based on its classification.^[11] CAA section 182, as interpreted in the EPA's implementation regulations at 40 Code of Federal Regulations (CFR) 51.1308 through 51.1317, sets for air agencies to submit and implement State Implementation Plan (SIP) revisions to satisfy the applicable attainment planning elements. These provisions also establish the timeframes by which NAAs must attain the 2015 ozone NAAQS.

Effective on August 3, 2018, the EPA designated 51 areas throughout the country, including the UB in Utah, as nonattainment for the 2015 ozone NAAQS.^[12] In a separate action, the EPA set classification thresholds and attainment dates based on each NAAs ozone DV.^[13] The EPA established the attainment date for Marginal, Moderate, and Serious NAAs as 3 years, 6 years, and 9 years, respectively, from the effective date of designations. Thus, the attainment date for the UB ozone NAA was August 3, 2021, which was to be calculated using monitored ozone data from 2018-2020.^[14] Applicable SIP requirements for Marginal ozone NAAs are provided in table 1 of this document.^[15]

The UB ozone NAA, initially classified as Marginal for the 2015 ozone NAAQS, was granted a 1-year attainment date extension under CAA section 181(a)(5) in October 2022 which was requested by both the State and Tribe.^[16] This extended the attainment date from August 3, 2021 to August 3, 2022. Because DVs are based on the three most recent, complete calendar years of data preceding the attainment date, attainment must occur no later than December 31 of the year before the attainment date ( i.e., December 31, 2021, in the case of the UB Marginal NAA for the 2015 ozone NAAQS).

On March 29, 2022 and December 20, 2022, respectively, the State and Tribe requested a second 1-year extension under CAA section 181(a)(5) of the Marginal attainment date which would have extended the Marginal attainment date from August 3, 2022 to August 3, 2023. In response to the State's and Tribe's requests, on April 10, 2024, the EPA published a notice of proposed rulemaking, based on certified ozone monitoring information through 2022, to grant the requests for a second 1-year Marginal attainment date extension and determine that the area attained by the new attainment date.^[17] While the EPA concluded that the area did not attain the 2015 ozone NAAQS by the Marginal area attainment date of August 3, 2022, based on a final 2019-2021 DV of 0.078 ppm, and as required per CAA section 181(b)(2)(A), we did conclude in both our April 10, 2024 proposal and December 16, 2024 final rule that the eligibility criteria for a state to request an attainment date extension had been met, per 40 CFR 51.1307(a)(1).^[18] Namely, these criteria include submitting all Marginal area SIP elements to the EPA and having certified ozone monitoring data for specific years that are all at or below the CAA established thresholds. This conclusion was based on a two-year average fourth highest daily maximum 8-hour concentration of 0.069 ppm for the years 2020 and 2021.^[19] Additionally, certified data through December 31, 2022, showed that the three-year average for 2020-2022 was 0.067 ppm, which is attaining the 2015 ozone NAAQS (see table 2 of this document). Further, Utah certified that they complied with all requirements and commitments pertaining to this area in their approved implementation plan and monitoring data completeness.^[20]

As part of the December 2024 rulemaking, the EPA held a public comment period that closed on May 9, 2024. The EPA received comments from nine commenters, with two in support and seven in opposition.^[22] Two themes dominated the opposing comments: high 2023 ozone values and environmental justice (EJ) concerns. Consequently, on December 16, 2024, the EPA published a final rule in the Federal Register using its discretionary authority under CAA section 181(a)(5) to deny the request for a second 1-year extension and determined that the UB ozone NAA failed to attain the 2015 ozone NAAQS by the August 3, 2022 attainment date.^[23] As shown in table 2 of this document, two of the seven regulatory monitors in this area had a 2019-2021 DV greater than the standard of 0.070 ppm.^[24] For that reason, the EPA reclassified the area to Moderate by operation of law with an effective date of January 15, 2025 and an attainment date of August 3, 2024, in the December 16, 2024 final rule. In that action, the EPA committed to addressing SIP revision and implementation deadlines for the UB in a separate rulemaking given the attainment date was in the past.

Following publication of the 2024 final rule, the EPA received requests for reconsideration from the State on February 14, 2025, the Tribe on January 14, 2025, UPA on February 14, 2025, and the Utah Congressional delegation on January 14, 2025.^[25] Petitions to review the 2024 final rule were filed with the 10th Circuit Court of Appeals by the State on January 22, 2025, the Tribe on February 14, 2025, UPA on January 21, 2025, and Seven County Infrastructure Coalition on January 30, 2025. On February 25, 2025, the EPA granted the petitions for reconsideration and stated our intention to undergo a notice-and-comment rulemaking.^[26] Petitioners also filed motions to stay the 2024 final rule. The EPA did not oppose the motions to stay the final rule. On May 22, 2025, the 10th Circuit Court of Appeals granted the Petitioners' stay pending the outcome of the administrative reconsideration.^[27] The practical implication of the judicial stay is that the UB ozone NAA is currently classified as Marginal as of the date of this proposal. Petitions and related documents and correspondence are included in the docket for this rule ( see https://www.regulations.gov, Docket No. EPA-R08-OAR-2024-0001).

After reconsidering the December 2024 final rule, the EPA now finds that Utah sufficiently met the statutory criteria for a second 1-year attainment date extension and the Agency is no longer exercising its discretion to deny the State's and Tribe's request, which would have imposed additional obstacles that Congress did not specifically require.

II. Legal Authority

The statutory authority for the actions in this proposed rule is provided by the CAA, as amended (42 U.S.C. 7401, et seq. ). Relevant portions of the CAA include, but are not necessarily limited to, CAA section 181. Additionally, the EPA has authority to reconsider and revise, rescind, and repeal final actions to the extent permitted by law so long as it offers a reasonable basis for doing so and considers applicable reliance interests.^[28] CAA section 181(b)(2)(A) provides that, within six months following the applicable attainment date, the EPA must determine whether an ozone NAA attained the ozone standard based on the area's DV as of that date. If an area fails to attain by its attainment date and does not receive a 1-year attainment date extension, CAA section 181(b)(2)(A) requires the EPA to determine that an ozone NAA failed to attain the ozone standard by the applicable attainment date, and requires the area to be reclassified by operation of law to the higher of (1) the next higher classification; or (2) the classification corresponding to its DV at the time of the determination. Section 181(b)(2)(B) of the CAA requires the EPA to publish the determination of failure to attain and accompanying reclassification in the Federal Register no later than six months after the attainment date, which was February 3, 2023, for the UB ozone NAA.

Per CAA section 181(a)(5), the EPA has discretion (“the Administrator may”) to extend an area's applicable attainment date by one additional year upon application by any state if the state meets the two criteria under CAA section 181(a)(5). See also40 CFR 51.1307. This section is intended to provide flexibility where an area is close to achieving attainment and can likely do so with additional time. Rather than require an area to attain the NAAQS by a first extended attainment date, the provision expressly allows for a maximum of two 1-year extensions for a single area. ( printed page 21757)

Under CAA section 181(a)(5), the first criterion is satisfied if a state can demonstrate that it is in compliance with its approved SIP. See Delaware Dept. of Nat. Resources and Envtl. Control v. EPA, 895 F.3d 90, 101 (D.C. Cir. 2018) (holding that the CAA requires only that an applying state with jurisdiction over a NAA comply with the requirements in its applicable SIP, not every requirement of the Act). A state may meet this requirement by certifying its compliance, and in the absence of such certification, the EPA may determine whether the criterion has been met. See Delaware, 895 F.3d at 101-102.

The second criterion, as it applies to a second 1-year extension, is that the area's fourth highest daily maximum 8-hour value, averaged over both the original attainment year and the first extension year, must be no greater than the level of that NAAQS. With respect to the second criterion, for the 2015 ozone NAAQS the EPA has interpreted the air quality criterion of CAA section 181(a)(5)(B) to mean that an area's fourth highest daily maximum 8-hour value, averaged over both the original attainment year and the first extension year, must be no greater than 0.070 ppm.

III. Proposed Action

This action addresses the UB ozone NAA, which includes portions of Duchesne and Uintah Counties in Utah. This notice-and-comment rulemaking arises out of the EPA's February 25, 2025 granting of petitions for reconsideration of the December 16, 2024 final rule submitted by the State, Tribe, UPA, and Utah's Congressional delegation. After reconsideration and review of additional technical information available at the time of the 2024 action, the EPA is proposing to repeal the December 16, 2024 final rule. That rule found the UB ozone NAA failed to attain by August 3, 2022, and reclassified the area as Moderate by operation of law. The repeal would retain the area's Marginal nonattainment classification. Technical information made available since the final action, including certified 2024 and preliminary 2025 ozone monitoring data also supports the EPA's proposal to retain the area's Marginal nonattainment classification.^[29]

Table 3 of this document provides a summary of the data from the UB ozone NAA relevant to the area demonstrating attainment by the Marginal attainment date. While the 2019-2021 DV does not show attainment, the two-year average of 2020-2021 qualifies the UB ozone NAA for a second 1-year attainment date extension.^[30] Thus, the EPA is also proposing to grant the second 1-year extension from August 3, 2022, to August 3, 2023. Consequently, based on the 2020-2022 DV, the region did not exceed 0.070 ppm, and the EPA is therefore also proposing to find that the UB ozone NAA attained by the new attainment date of August 3, 2023. The EPA requests comment on these proposed actions. See the DATES section in this document for deadline to submit comments.

This proposed determination of attainment by the attainment date would not constitute formal redesignation to attainment as provided for under CAA section 107(d)(3). Redesignations to attainment require, among other things, that the states responsible for ensuring attainment and maintenance of the NAAQS have met the applicable requirements under CAA section 110 and part D, and to submit to the EPA for approval a maintenance plan to ensure continued attainment of the standard for 10 years following redesignation, as provided under CAA section 175A.

If the EPA takes final action determining that the UB ozone NAA attained the 2015 ozone NAAQS by the revised attainment date of August 3, 2023, the UB will remain a Marginal NAA under the 2015 ozone NAAQS and must continue to meet the planning requirements specified in CAA section 182(a).

The EPA seeks comment on all aspects of the proposed actions described in this preamble, including with respect to our statutory authority to reconsider and repeal the December 16, 2024 final rule and any changes in interpretation and policy relevant thereto. Because this action would, if finalized, relieve certain obligations for the State of Utah, we do not believe there are reasonable and cognizable reliance interests that would be adversely impacted by finalizing this action as proposed. Nevertheless, we seek comment on whether such reliance interests exist and, if so, how the EPA should consider them in taking any final action on this proposal.

IV. Tribal Consultation

In accordance with the EPA Policy on Consultation and Coordination with Indian Tribes, the EPA offered an opportunity for consultation to the Tribe prior to this proposed EPA action (see section V.G. of this document).^[32]

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review

This action is not a significant regulatory action and was therefore not submitted to the Office of Management and Budget (OMB) for review. ( printed page 21758)

B. Executive Order 14192: Unleashing Prosperity Through Deregulation

Executive Order 14192 does not apply because a determination of attainment is an air quality designation which is exempted from review under Executive Order 12866.

C. Paperwork Reduction Act (PRA)

This rule does not impose an information collection burden under the PRA. This action does not contain any information collection activities.

D. Regulatory Flexibility Act (RFA)

I certify that this action will not have a significant economic impact on a substantial number of small entities under the RFA (5 U.S.C. 601 et seq.). This action will not impose any requirements on small entities. A CAA determination of attainment by the attainment date, and reclassification of the UB ozone NAA, will not in and of themselves create any new requirements beyond what is mandated by the CAA. This action would not itself directly regulate any small entities.

E. Unfunded Mandates Reform Act (UMRA)

This action does not contain an unfunded mandate as described in UMRA, 2 U.S.C. 1531-1538 and does not significantly or uniquely affect small governments. The action implements mandates specifically and explicitly set forth in the CAA without policy discretion by the EPA.

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. The division of responsibility between the Federal government and the states for purposes of implementing the NAAQS is established under the CAA.

G. Executive Order 13175 Consultation and Coordination With Indian Tribal Governments

Executive Order 13175 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 action has Tribal implications, because it proposes actions that will affect the ozone classification of a large area of Indian country within the Uintah and Ouray Reservation. However, it will neither impose substantial direct compliance costs on federally recognized Tribal governments, nor preempt Tribal law.

The EPA provided an opportunity for consultation with Tribal officials early in this rulemaking under our Policy on Consultation and Coordination with Indian Tribes. The goal is to ensure meaningful and timely input. The Tribe may request consultation and/or submit comments to the EPA at any point during the rulemaking process, including during the public comment period.

H. Executive Order 13045 Protection of Children From Environmental Health and Safety Risks

EPA interprets Executive Order 13045 as applying only to those regulatory actions that concern environmental health or safety risks that EPA has reason to believe may disproportionately affect children, per the definition of “covered regulatory action” in section 2-202 of the Executive Order. This action is not subject to Executive Order 13045 because it does not establish an environmental standard intended to mitigate health or safety risks.

I. Executive Order 13211 Actions That Significantly Affect Energy Supply, Distribution, or Use

This action is not subject to Executive Order 13211 because it is not a significant regulatory action under Executive Order 12866.

J. National Technology Transfer and Advancement Act (NTTAA)

This rulemaking does not involve technical standards.

91 FR 21753