EPA Superfund Site

SILVER BOW CREEK/BUTTE AREA

MT | EPA ID MTD980502777

About this site’s exposure pathways: As of September 2025, the Silver Bow Creek/Butte Area Superfund Site is considered "Current Human Exposure Not Under Control." This large Site includes approximately 26 miles of stream and streamside habitat, the urban centers of Butte and Walkerville, rural areas outside of Butte, the Berkeley Pit and the underground mine workings of the historic Butte Mining District, and the treatment settling lagoons at the Warm Springs Ponds. The main contaminants of concern are heavy metals and arsenic.
The remedial design and remedial action work under the consent decree for the Butte Priority Soils Operable Unit 8 is progressing to address this high priority area. The EPA has provided an Updated Soil Lead Guidance for CERCLA sites and RCRA Corrective Action Facilities (Updated Lead Guidance) on January 17, 2024. The Updated Lead Guidance has lowered the recommended regional screening level for lead-contaminated residential soil sites. Based on the Updated Lead Guidance, the EPA evaluated the potential presence and extent of soils that may present current and future-potential exposure risk to sensitive populations. While implementation of the Updated Lead Guidance may take several years, the EPA will share information on planned activities and results as they become available.
EPA completed the Remedial Investigation for the West Side Soils Operable Unit 13 and is currently drafting the Feasibility Study Report. EPA will develop a Record of Decision (planned date is March 2027) to address risks to human health and the environment posed by that remaining contamination.
Human exposure is expected to be under control once the completion of the remedial action activities at Warm Springs Ponds Operable Units have been completed; this date is expected to be 12/31/2034. EPA will update this date as necessary based on the implementation of the Updated Lead Guidance and the number of residential properties that are expected to require remediation within Butte Priority Soils Operable Unit 8. EPA has an extensive community outreach program which includes providing the community with information on how to reduce exposures to potentially contaminated sources.