Westlake Landfill

Overview

Westlake Landfill sits on 200 acres in Bridgeton, Missouri. In 1973, uranium ore processing residues were brought to the site and used as daily cover during disposal of municipal waste and construction debris. The site was first assessed in 1980 and added to the National Priorities List in 1990. Cleanup is organized into three operable units (OUs): OU1 covers the radiologically contaminated waste cells, OU2 covers landfill areas without radioactive contamination, and OU3 covers groundwater beneath the site.

Radioactive materials are the dominant concern. Thorium-230 and Radium-226, along with their decay products, account for more than 95 percent of the health risk at the site. More than 140 chemical substances have been identified across soil, solid waste, groundwater, and landfill gas. These include volatile organic compounds such as benzene, metals such as arsenic, lead, and chromium, pesticides, polychlorinated biphenyls, and radioactive isotopes including uranium, radium, and radon. Arsenic, benzene, and vinyl chloride have also been found in groundwater. Currently, human exposure is under control due to access restrictions and fencing. Groundwater migration remains uncertain, and plants, soil invertebrates, and small burrowing animals may be at risk from contaminant exposure.

For OU1, the EPA selected an amended cleanup plan in September 2018. It calls for excavating radiologically impacted material down to roughly 8 to 20 feet, transporting it to an off-site disposal facility, and placing an engineered cap over any remaining contamination. A removal action that began in February 2016 concluded in September 2021, and a second removal phase is estimated to finish between January and March 2027. Pre-excavation confirmation sampling was completed in March 2026. The remedial design is projected to finish between August and October 2026, after which construction will begin. For OU2, remedial design is expected to wrap up between July and September 2027. An Explanation of Significant Differences issued in January 2025 addressed cost, volume, and treatment area changes for both OU1 and OU2 without altering the overall cleanup strategy. For OU3, field investigation began in November 2020 and remains ongoing.

Community members can get involved through the site's Community Advisory Group, which serves as a direct link between residents and the EPA, state regulators, and other federal agencies. A Technical Community Advisory Group meeting was held on March 24, 2026. Residents can also sign up for Westlake Updates, an email newsletter with site status information. Qualified community groups can apply for Technical Assistance Grants of up to $50,000 to hire independent technical advisors. Direct questions can go to the Community Involvement Coordinator or the Remedial Project Manager.