Published on July 11, 2023
The Weld County Board of Commissioners is disappointed by a decision of the U.S. Court of Appeals for the D.C. Circuit that reviewed the U.S. Environmental Protection Agency’s (EPA) final decision to move the ozone nonattainment area boundary for the 2015 ozone standards to include all of rural northern Weld County. The court affirmed EPA’s 2021 designation despite EPA’s reliance on less than current data and modeling results, stating that it was reasonable for EPA to use older data for purposes of national consistency, among other things.
The board filed suit against EPA seeking to overturn the designation on grounds that the best available data do not support EPA’s decision to move the boundary. The board’s detailed arguments that the lack of data indicating contributions to ozone violations from sources in northern Weld County was rejected by the Court because “some air parcels” flow from northern Weld County into the metro area.
The EPA failed to consider the most recent four plus years of available monitoring and weather data and ozone photochemical modeling results in making its boundary designation, but the Court deferred to EPA in making this ‘highly technical’ determination. The Court made no mention of EPA selectively removing certain data from its technical support documentation, as raised by Weld County in its briefs. The Court also found permissible EPA’s reliance on monitoring data that was wildfire-smoke-influenced because the State of Colorado had not sought to exclude such data as non-representative. The board is evaluating its options for review.
The case is captioned Board of County Commissioners of Weld County, Colorado v. Michael S. Regan, Administrator, Environmental Protection Agency, and United States Environmental Protection Agency. The board is represented in this matter by John Jacus, Shannon Stevenson, and Kathleen Pritchard of Davis Graham & Stubbs LLP and Ethan Shenkman and Charlie Birkel of Arnold & Porter Kaye Scholer LLP.