Amcast Industrial Corporation was a former automotive supplier in Cedarburg, Wisconsin, north of Milwaukee. The company contaminated its facility and the surrounding area with polychlorinated biphenyls, commonly called PCBs. The site was added to the EPA's National Priorities List in September 2009, after the company filed for bankruptcy in 2004 and an initial investigation stalled. Cleanup work is now in the design phase, with construction not yet started.
PCBs are the primary concern, found in soil, sediment, groundwater, and fish tissue. The contamination spread to soil under facility buildings, nearby sewers, stormwater retention ponds, and private properties southeast of the plant. Beyond PCBs, the EPA identified 50 total contaminants of concern. These include heavy metals such as lead, arsenic, chromium, copper, and manganese, as well as organic chemicals like benzene, chloroform, and polycyclic aromatic hydrocarbons including benzo[a]pyrene and naphthalene. Chlorinated solvents and phthalates are also present. All 50 contaminants fall under Operable Unit 01, which covers soil and sediment across the entire site.
The EPA finalized its cleanup plan, called a Record of Decision, in September 2023. That plan calls for excavating contaminated soil, dredging pond sediments, remediating sewers, and disposing of material offsite. Additional steps include dewatering, building sealant application, revegetation, and ongoing monitoring of fish tissue, groundwater, and sediment. Institutional controls will also be put in place. A second operable unit covers groundwater sitewide, but no cleanup decision has been issued for it yet. The U.S. Army Corps of Engineers is developing detailed design drawings and cost estimates, with additional sampling planned through 2025 and the design expected to finish in 2026.
Human exposure is not yet under control, meaning unsafe contamination levels have been detected and people could reasonably be exposed. Groundwater migration status is uncertain because there is not enough data yet to determine whether contaminated groundwater movement has stabilized. Remedial design began in September 2024 and is estimated to conclude between April and November 2026. Cleanup construction is estimated to begin between April and June 2026, with additional phases planned through March 2028.
Community members can contact EPA representatives directly with questions. Site documents, including the Record of Decision, a 2015 Remedial Investigation Report, a 2020 Feasibility Study, and a 2022 Community Involvement Plan, are available at Cedarburg City Hall and Cedarburg Public Library, both in Cedarburg, Wisconsin.
