EPA’s nonattainment designations of two counties—one in Montana and one in Michigan—under the Agency’s 2010 National Ambient Air Quality Standards (NAAQS) for sulfur dioxide (SO2) were challenged in the U.S. Court of Appeals for the D.C. Circuit in two separate petitions that the court consolidated. According to the court, the two claims had “virtually nothing in common” except that they were both challenging the designations. In both instances the D.C. Circuit panel found in favor of the EPA.
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In the first case, a group of businesses and labor unions called the Treasure State Resource Industry Association challenged EPA’s nonattainment designation under the SO2 NAAQS for Yellowstone County, Montana. The Association argued that EPA’s designation in August 2013 was illegal for two reasons.
The second case concerns EPA’s nonattainment designation for a part of Wayne County, Michigan. U.S. Steel argued that a nonattainment designation should have been issued for neighboring Monroe County, which contains the Monroe Coal-fired Power Plant, a source, added U.S. Steel that significantly contributes to nonattainment in Wayne County. The Clean Air Act (CAA) requires that areas that generate pollution that is a significant cause of other areas being in nonattainment must also be designated nonattainment even if pollution levels in the originating county are not in exceedance of the NAAQS.