The Big River Mine Tailings/St. Joe Minerals Corp. site includes all of St. Francois County except for a small portion of southern St. Francois County, where the Mine La Motte Operable Unit for the Madison County Mines NPL site is located. St. Francois County is located on the middle portion of an area known as the Old Lead Belt. Mine waste has
contaminated soil, sediment, surface water and groundwater at the site with heavy metals, primarily lead. Mining operations beginning in the early 1700s resulted in eight large areas of mine waste in this rural region, approximately 110 square miles in size. The site was listed on the National Priorities List on October 14, 1992. Six Operable Units (OUs) are designated for the site: OU-00 Mine Waste Source Areas Remedial Action completed; OU-1 Residential Properties, OU-2 Big River, OU-3 Interim Program and Halo Removal Action completed in 2018, OU-4 Railroad Lines, OU-5 Doe Run Mine Tailings.
OU-1-Residential Properties has a signed 2011 Record of Decision for remedial action, but it does not currently address residential properties with lead concentrations between 200 to 399 ppm. This Removal Action addressed residential properties with sensitive populations referred to the Removal Program in July 2024. The Region 7 Remedial Program referred the properties due to presence of lead between 200 to 399 ppm and where a Missouri Department of Health and Senior Services' referral documented the presence of a sensitive population with a lead exposure residing at the residence.
OU-1 is divided into two main areas; the Response Area, which is the area within one mile of chat and tailings waste at each of the mine waste areas in St. Francois County; and the remaining residential yards outside of the Response Area. Most of work inside the Response Area has been conducted under enforcement orders and/or funded by Potentially Responsible Parties (PRPs). PRPs were identified for work inside the Response Area due to the proximity to the waste piles and potential for lead to migrate from those piles. Work outside the Response Area has been conducted by the EPA due to difficulties in identifying PRPs for those areas.
This Removal Action focused only on properties inside the Response Area and included the excavation and disposal of lead-contaminated soils from a total of eight residential properties following procedures described in the Superfund Residential Lead Sites Handbook (Office of Superfund Remediation and Technology Innovation, March 2024). Excavation began on May 5, 2025, and was completed on June 23, 2025. Restoration work was completed on August 1, 2025.
