The Kerr-McGee Kress Creek Site/West Branch DuPage River Superfund Site (KMS) is located in West Chicago, DuPage County, Illinois and includes almost seven miles of creek and river sediment, banks and floodplain soils contaminated with radioactive thorium residue. The KMS includes about a mile and a half of Kress Creek stretching from a storm sewer outlet to where the creek empties into the West Branch DuPage River. From there the Site stretches about five miles down the West Branch DuPage River past the Warrenville Dam to the McDowell Dam. The radioactive thorium waste material was generated by a processing facility that operated in West Chicago between 1932 and 1973. Thorium and other elements were separated from ores at the plant using an acid process, which created waste materials known as mill tailings that were stored at the facility. Wastes from the facility entered Kress Creek through a storm sewer, contaminating sediments in the Creek and the West Branch DuPage River. Thorium was also deposited onto floodplains during high water periods. Waste from the facility was also used as fill material at a sewage treatment plant and eroded into the West Branch DuPage River. The U.S. Environmental Protection Agency placed the KMS on the Superfund National Priorities List in 1990 (sewage treatment plant) and 1991 (creek and river) (EPA 2014).
The KMS is located within the drainage basin of the West Branch DuPage River, which flows through the Site. Kress Creek and adjacent wetlands and uplands provide habitat that supports a variety of migratory birds including waterfowl, songbirds and other wildlife. Injury to these trustee resources occurred as a result of the release of hazardous substances from the site. The Final Restoration Plan for the Yeoman Creek Landfill Superfund Site and the KMS was prepared by DOI in accordance with CERCLA, (42 U.S.C. § 9601, et seq.) and the CERCLA NRDAR Regulations, (43 C.F.R. Part 11).