Sierra Club v. Environmental Protection Agency, No. 15-1465 (D.C. Cir. 2021)Annotate this Case
In these consolidated cases, petitioners challenge four provisions of the EPA's 2015 and 2018 rules implementing the National Ambient Air Quality Standards for ozone. Petitioners challenge four features of the 2018 Rule: (1) the interprecursor trading program, as well as provisions (2) allowing states to demonstrate compliance with the Act’s reasonable further progress milestone requirements through an implementation-based method, (3) allowing states to choose between two options for the reasonable further progress baseline year, and (4) allowing nonattainment areas to use already-implemented measures to satisfy the Act's contingency measures requirements.
The DC Circuit vacated two provisions—the interprecursor trading program and the interpretation of the Clean Air Act's contingency measures requirements—because they contravene the statute's unambiguous language. The court vacated another provision—the implementation of the milestone compliance demonstration requirement—because it rests on an unreasonable interpretation of the statute. Finally, the court denied the petition for review with respect to the alternative baseline years provision. Therefore, the court granted in part and denied in part the petitions for review.