Proposed rule · 2026-07904

Utah; Uinta Basin; 2015 8-Hour Ozone National Ambient Air Quality Standard; Reconsideration and Repeal of Finding of Failure To Attain and Reclassification to a Moderate Nonattainment Area; Extension of the Attainment Date and Determination of Attainment by the Marginal Attainment Date

The U.S. Environmental Protection Agency (EPA or Agency) is proposing to repeal the December 16, 2024 final rule in which we denied a request by the State of Utah (State) and the Ute Indian Tribe of the Uintah and Ouray Reservation (Ute Indian Tribe or Tribe) for an extension of the attainment date for the Uinta Basin (UB), Utah Marginal nonattainment area (NAA) under the 2015 ozone National Ambient Air Quality Standard (NAAQS), determined that the area failed to attain the Clean Air Act (CAA) 2015 ozone NAAQS by the applicable Marginal attainment date of August 3, 2022, and reclassified the area by operation of law to a Moderate ozone NAA. The EPA is also reproposing to grant the second 1-year extension of the Marginal attainment date from August 3, 2022 to August 3, 2023 and to determine that the area attained the 2015 ozone NAAQS based on certified ozone monitoring data from 2020-2022. If we finalize this proposed action, the UB area would no longer be subject to the CAA requirements pertaining to reclassification upon failure to attain and therefore would remain classified as a Marginal NAA for the 2015 ozone NAAQS.