Pursuant to CERCLA section 106(b), 42 U.S.C. § 9606(b), Cyprus Amax Minerals Company (“Cyprus Amax”) petitioned for reimbursement of costs associated with its compliance with a unilateral administrative order (“UAO”) issued under CERCLA section 106(a), 42 U.S.C. § 9606(a). The UAO, issued by U.S. EPA Region VI on February 2, 1994, required Cyprus Amax to remove soil that had become contaminated with lead and cadmium as a result of various smelting operations in Bartlesville, Oklahoma, between 1907 and 1993.