EPA Superfund site
ST. LOUIS RIVER SITE
Human exposure is NOT currently under control
Data limitations: Proximity to a Superfund site boundary does not mean your property is contaminated. EPA site boundaries show the area designated for cleanup, not the full extent of contamination. Groundwater plumes can extend beyond site boundaries. This tool shows publicly available EPA federal data. It is not affiliated with or endorsed by EPA, and is not a substitute for a professional environmental assessment.
About this site's exposure pathways
As of June 2026, EPA considers the St. Louis River Superfund site "Current Human Exposure Not Under Control" (HENC) because tar pits, tar seeps, tar-contaminated soil, areas with oily liquids, and contaminants such as mercury and lead exceed Tier 2 Minnesota Industrial Soil Reference Values (equating to 10-5 excess lifetime cancer risk or hazard quotient of 1 for an individual contaminant) are present. The potentially responsible parties (PRPs) have completed several phases of cleanup under State oversight in both Site areas. Contaminated upland portions of the Site are fenced to prevent access; however, there is evidence of site trespassing, and institutional controls are needed to protect future users of the Site. Individuals can reduce their exposure risk by following posted signage warning potential trespassers to stay off the fenced portions of the Site. Sediment operable units at the US Steel portion of the Site were cleaned up through the Great Lakes Legacy Act; the rest of the site is currently designated as State Enforcement Lead. EPA expects that PRP actions will address tar seeps and direct contact risk to soil in the coming several years, with an estimated completion date of December 2030.