Mining in Madison County from the early 1700s through the mid-1900s left behind 13 major tailings and chat deposit areas, mostly contaminated with lead. Erosion spread that contamination into soils, sediments, surface water, and groundwater. Contaminated material was also moved onto residential properties as fill, driveway aggregate, and foundation material, affecting roughly 42 percent of homes across the county. The site was added to the National Priorities List on September 29, 2003.
Contaminants include arsenic, lead, cadmium, copper, cobalt, manganese, nickel, zinc, vanadium, aluminum, and iron. These metals show up in groundwater, soil, surface water, sediment, and solid waste across multiple areas of the site. Lead is the most widespread, found across the residential, Conrad, and Catherine/Skaggs Piles areas. Arsenic and cobalt are concentrated mainly in the Catherine/Skaggs Piles area.
Cleanup is managed through eight operable units, each covering a different geographic area. More than 5,700 properties have been sampled and over 2,100 remediated since 2003. The Conrad unit finished remedial work in September 2019 and transferred to state oversight. The Catherine/Skaggs Piles unit finished in June 2021 and is also under state-led operation and maintenance. A supplemental residential cleanup is funded through the Bipartisan Infrastructure Law and runs through 2027. Several other units, including Silver Mines, the Little Saint Francis River Watershed, and Abandoned Railroads, are still in study and planning phases, with work expected through 2028. The U.S. Forest Service manages contamination on its lands with EPA coordination. Environmental covenants and zoning restrictions limit land use at capped areas to prevent exposure.
Human exposure is not currently under control at the site. A 2007 baseline health risk assessment identified risks from metals-contaminated residential soils, groundwater near mine and tailings areas, and contaminated sediments and fish in some locations. Physical construction is not yet complete across the entire site, and the site has not been deleted from the National Priorities List. The most recent five-year review was completed on August 14, 2023, and the next is estimated for August through October 2028.
Community members can get involved through the Madison County Health Department's Quarterly Environmental Roundtable in Fredericktown. Residents can call the Health Department at (573) 783-2747 to find out dates and locations. For questions about the site directly, contact EPA's Community Involvement Coordinator or Remedial Project Manager.
