Environment
Bringing back stream life through long-term cleanup and restoration across the Silver Bow Creek watershed.
How the Cleanup Is Organized
The Silver Bow Creek/Butte-Area Superfund site cleanup focuses on the Silver Bow Creek watershed, an interconnected ecosystem that was impacted by mining, ore processing, and smelting from the late 1800s through much of the 1900s. These impacts affect both environmental health and public health.
Because the Butte-Area Superfund site is large and complex—often described as a “mega-site”—the EPA divided it into Operable Units (OUs). These units are defined cleanup areas with their own studies, plans, and timelines. While each Operable Unit moves at its own pace, the EPA reviews overall progress across the site every five years.
The Silver Bow Creek/Butte Area Superfund Site includes the Berkeley Pit and 10,000 miles of underground mine workings beneath Butte. It extends downstream along Silver Bow Creek to the 2,600-acre Warm Springs Ponds area.
EPA 5-Year Review
Cleanup progresses piece by piece, with the EPA reviewing overall progress every five years. The latest review was completed in August 2026. The next 5-Year Review should be available in 2031.
Operable Units
Browse the Operable Units to see what they cover, current work, and recent progress.
Butte Priority Soils
West Side Soils
Montana Pole & Treatment Plant
What’s New
Get the latest updates on environmental cleanup progress, restoration work, site studies, and key milestones across the Operable Units.
CTEC gives public a look into Berkeley Pit bird-hazing techniques
Turquoise water greeted visitors as they stepped onto the Berkeley Pit viewing stand. The evening sun illuminated rock layers of the former open pit mine. Around 20 people gathered at the viewing stand on July 16 for a presentation on the waterfowl protection...
EPA Residential Lead Proposed Plan Fact sheet (June 2026)
EPA’s fact sheet describing the Proposed Plan to lower residential lead cleanup level and increase the number of homes remediated.
EPA Residential Lead Proposed Plan (June 2026)
Complete document: EPA’s Proposed Plan to lower residential lead cleanup level and increase the number of homes remediated.