EPA Restores Marginal Status for Uinta Basin Ozone
Environmental Protection Agency
The Environmental Protection Agency (EPA) intends to scrap a December 16, 2024, final decision that previously penalized the region for failing to meet federal air quality standards.
Public comments on the reversal are due by May 26, 2026.
The core dispute revolves around the 2015 national ambient air quality standard for ozone, set at 0.070 parts per million (ppm).
Late last year, the EPA determined the Uinta Basin failed to meet this threshold by its August 3, 2022, deadline, that triggered an automatic statutory reclassification, bumping the area from a "Marginal" to a "Moderate" nonattainment zone, and creating a regulatory escalation that requires significantly stricter state and tribal implementation plans.
The State of Utah, the Ute Indian Tribe, and industry groups pushed back heavily by filing petitions for administrative reconsideration and subsequently secured a judicial stay from the 10th Circuit Court of Appeals.
Now, the EPA is yielding by acknowledging that the region meets the statutory criteria for a second one-year extension and admits that enforcing the Moderate reclassification would impose obstacles that Congress did not specifically mandate.
The new standard states, (1) the basin's attainment deadline is retroactively extended from August 3, 2022, to August 3, 2023. (2) Certified ozone monitoring data for the 2020–2022 period shows a design value of 0.067 ppm, falling safely below the 0.070 ppm legal limit. (3) The EPA formally recognizes the area attained the standard by the revised deadline, allowing it to shed the "Moderate" label and retain its baseline "Marginal" classification.
The relief is localized but economically and legally significant. The scope of the rule explicitly targets the Uinta Basin nonattainment area, encompassing portions of Duchesne and Uintah Counties, as well as Indian country within the Uintah and Ouray Reservation.
By freezing the classification at Marginal, the EPA avoids triggering new regulatory requirements for the area.
The agency explicitly notes that this action does not impose direct compliance costs on small entities, nor does it establish unfunded federal mandates on local governments.
However, a permanent victory remains out of reach for now. To fully exit nonattainment status and be formally redesignated to "attainment," Utah must still draft and submit a comprehensive 10-year maintenance plan proving it can keep ozone levels suppressed.
