United States v. ASARCO Inc.

I. BACKGROUND

In 1983, the Environmental Protection Agency (EPA) placed the “Bunker Hill Mining Site” on the National Priorities List (NPL), a list of the most contaminated sites in the nation. The list is maintained by the EPA pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERC-LA). See 42 U.S.C. § 9601 et seq. The listing of the Bunker Hill site reflected widespread contamination caused by more than 100 years of mining and mining-related activity. Consistent with EPA policy, the listing did not set forth any site boundaries. Over the next several years, however, the EPA referred to the Bunker Hill Superfund Site in various documents as a twenty-one square mile box, bounded on the west by the town of Pinehurst and on the east by the town of Kellogg, in Shoshone County, Idaho (the “Box”).

In March 1996, the United States, at the request of the EPA, the Department of Interior, and the Department of Agriculture, filed an action against various owners and operators of mining and mineral processing facilities to recover, among other things, damages under CERCLA for injury to natural resources with respect to the “Bunker Hill facility.” See 42…