Sierra Club v. EPA, No. 18-9507 (10th Cir. 2020)Annotate this Case
The issue this case presented for the Tenth Circuit's review involved an interpretation of an environmental regulation addressing the renewal of permits under Title V of the Clean Air Act. The statute and accompanying regulation allowed renewal of these permits only if they ensured “compliance with” all of the “applicable requirements.” The term “applicable requirements” was defined in the regulation, but not the statute. The Sierra Club interpreted the regulatory definition to require compliance with all existing statutory requirements; the EPA interpretd the regulatory definition more narrowly, arguing that the applicability of certain requirements was determined by the state permit issued under a separate part of the Clean Air Act (Title I). The Tenth Circuit agreed with the Sierra Club’s interpretation: the regulatory definition of “applicable requirements” included all requirements in the state’s implementation plan, and Utah’s implementation plan broadly required compliance with the Clean Air Act. So, the Court concluded, all of the Act’s requirements constituted “applicable requirements” under the regulation.