Disimone

Barry Disimone and Donald Steuter (“Petitioners”) filed this action against the United States Environmental Protection Agency (“EPA”), asking this court to order EPA to disapprove an Arizona State Implementation Plan and reinstate a withdrawn Federal Implementation Plan. We hold that EPA acted in disobedience of an order of this court in withdrawing the federal plan and approving a state plan and we grant the petition.

FACTUAL AND PROCEDURAL BACKGROUND

Following several years of unacceptably high levels of carbon monoxide in Maricopa and Pima Counties, Arizona, a citizen suit was filed against EPA for failing to perform its regulatory duties under the Clean Air Act, 42 U.S.C. §§ 7401 et seq. Delaney v. EPA, 898 F.2d 687 (9th Cir.1990) cert. denied 498 U.S. 998 , 111 S.Ct. 556 , 112 L.Ed.2d 563 (1990). Due to the state plan’s inadequacy under the Act, this court ordered EPA to disapprove the Arizona State Implementation Plan (“state plan”) it had approved for Maricopa and Pima counties and to promulgate a Federal Implementation Plan (“federal plan”) consistent with its own guidelines. Id. at 694 .

On November 15, 1990, Congress amended the Clean Air Act. Subsequently, EPA filed…