Velsicol Chemical Corp. operated a 54-acre plant in St. Louis, Michigan from 1936 to 1978, manufacturing pesticides and fire retardants. The site was added to the National Priorities List on September 8, 1983. Cleanup is organized into four operable units covering the main plant site, the Pine River, an athletic field area, and a downstream river section. Work is ongoing across all four areas, and the site has not been deleted from the list.
The site contains 27 confirmed contaminants. Groundwater holds DDT, chlorobenzene, carbon tetrachloride, trichloroethylene, benzene, vinyl chloride, and other chlorinated compounds. Soil contains polybrominated biphenyls (PBBs), DDT-related compounds, polychlorinated biphenyls (PCBs), benzo(a)pyrene, and heavy metals including copper, chromium, and zinc. Pine River sediments were contaminated through direct discharges, and a no-consumption advisory remains in place for all fish species in the area. People who eat contaminated fish and wildlife near the site face potential health risks. EPA has determined that human exposure is not under control and that contaminated groundwater movement has not been stabilized.
Major cleanup milestones include the removal of over 670,000 cubic yards of DDT-contaminated sediment from the Pine River between 1998 and 2006, which reduced DDT levels in fish by over 98 percent at a cost exceeding $100 million. More recently, a thermal treatment system ran at the former burn pit from May 2024 to February 2025, removing roughly 296,000 pounds of contamination. Nearly 3,200 tons of contaminated soil from an ash pile were excavated and disposed of off-site. Two containment barrier walls are now fully installed to keep contaminated groundwater from reaching the river and nearby homes. St. Louis switched to a new drinking water supply in October 2015 to address contamination concerns.
Current and upcoming work includes a comprehensive groundwater investigation starting in 2026, additional contracting for downstream Pine River cleanup also anticipated in 2026, and remedial action at the athletic field area estimated to begin in November 2026. Cleanup of the downstream Pine River section is expected to complete its investigation phase by early 2028. A September 2025 technical memorandum recommended reconsidering the original cleanup approach for one potential source area. The next five-year site review is estimated for late 2027.
Community members can follow progress by subscribing to the Velsicol listserv by sending a request to listserv@lists.epa.gov. Project documents and administrative records are available at the T. A. Cutler Memorial Library in St. Louis, Michigan. For direct questions, community members can contact the EPA's Community Involvement Coordinator or Remedial Project Manager.
