Montana Sulphur & Chemical Co. v. United States Environmental Protection Agency

In these appeals, consolidated for decision, we address the propriety of various actions taken by the United States Environmental Protection Agency (“EPA”) under the Clean Air Act with respect to Montana air quality from 1993 to 2008. In No. 02-71657, Montana Sulphur & Chemical Company (“Montana Sulphur”) seeks review of the EPA’s final rule which partially disapproved a proposed revision to Montana’s State Implementation Plan (“SIP”) governing sulfur dioxide (“S02”) emissions. 67 Fed.Reg. 22,168 (May 2, 2002). Montana Sulphur also seeks review of a prior EPA action in 1993 known as a “SIP Call,” which preceded the formal SIP revision and started the review process. 58 Fed.Reg. 41,430 (Aug. 4, 1993). The final agency action incorporated documents supporting its SIP Call — in particular EPA reliance on various modeling calculations — into the administrative record for partial disapproval of the SIP.

In No. 08-72642, Montana Sulphur seeks review of the EPA’s April 2008 final rule promulgating a Federal Implementation Plan (“FIP”) for the State of Montana’s S02 emissions. 73 Fed.Reg. 21,418 (April 21, 2008). The FIP is designed to fill perceived gaps the EPA identified in…