Public Notice: EPA Begins Sixth Five Year Review of Silver Bow Creek/Butte Area Superfund site

Summary

The U.S. Environmental Protection Agency (EPA) is conducting the sixth Five-Year Review (FYR) of the cleanup progress at Silver Bow Creek/Butte Area Superfund site in and around Butte, Montana.

Every five years, EPA evaluates the implementation and performance of cleanups to determine if they are, and will, remain protective of human health and the environment. The 2026 FYR will address six of the seven active Site operable units (OUs)—since the West Side Soils OU does not yet have an established remedy, or cleanup, no FYR is necessary.

EPA is overseeing the cleanup for most areas of the site, in consultation with the Montana Department of Environmental Quality (DEQ). DEQ is the lead implementing agency for Streamside Tailings area. Cleanup actions so far have included the removal of mining waste, treatment and/or cleanup of lead- and arsenic-contaminated properties and soils, amendment and capping of mine waste, stormwater controls, groundwater controls, capture and treatment, surface water controls, excavation of mine waste along the banks of Silver Bow Creek, and the reconstruction of Silver Bow Creek. Large source areas within the site that posed threats to human health and the environment have been removed and/or remediated. Remaining remedial elements at Butte Priority Soils Operable Unit (BPSOU) are currently being implemented per the BPSOU Consent Decree.

We want to hear from you! Community members are encouraged to share information that may be helpful in the FYR process. Community members who have questions or who would like to participate in a community interview are asked to contact Mackenzie by November 28, 2025.

The most current site information is available online at: Silver Bow Creek/Butte Area Superfund site