EPA Superfund Site

BARKER HUGHESVILLE MINING DISTRICT

MT | EPA ID MT6122307485

About this site’s exposure pathways: As of September 2025, the Barker Hughesville Mining District Superfund site is considered Current Human Exposure Not Under Control (HENC). EPA has completed the remedial investigations and is working on the Operating Unit 1 (OU1) feasibility study that addresses solid and aqueous source mine waste in the upper and middle Galena Creek watershed. EPA will follow this with an OU1 Record of Decision, which is planned for late 2026.
EPA has already overseen the completion of two Potentially Responsible Party (PRP)-lead removal actions to waste rock and tailings associated with the Block P Mining complex that has resulted in over 500,000 cubic yards of waste being placed in an onsite repository. EPA is also working with three PRPs to pilot test source control measures to address mine-influenced waters coming from three of the most contaminated discharging mine adits in the district. Remedial action completion of a final aqueous (water) source remedy media is anticipated to be completed in 2042. This exposure pathway is considered unacceptable based on EPA risk-based criteria because on-site workers, seasonal residents and recreationalists can be exposed through direct contact to mine waste, sediments and fluvial deposits containing thallium, manganese, lead and arsenic in contaminated source materials and residential soils as well as mine-influenced water discharging from multiple adits containing concentrations of lead, iron, zinc, cadmium, copper and thallium above federal maximum contaminant levels.
EPA continues to provide residents and recreationalists with information to reduce exposures to potentially contaminated sources such as soils, sediments, surface water and groundwater with a fact sheet anticipated to be mailed in early 2026.