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, completed in August 2021. The next 5-Year Review should be available in 2026.
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.
ARCO selects Butte Repository to dump toxic dirt in Silver Bow Creek cleanup
Date: Mar 27, 2026 Published By: KXLF News BUTTE -This summer, the plan is to start moving the more than 1 million cubic yards of contaminated dirt from Butte’s Silver Bow corridor and deposit it at the Butte Mine Waste Repository northeast of town. “This is a large…
Silver Bow Creek Greenway: A Legacy Worth Protecting
Date: Mar 24, 2026 Published By: The Montana Standard Guest View, Greenway Service District Board – Montana Standard March 24, 2026 In Superfund communities like ours, progress doesn’t always arrive with fanfare. Often it comes quietly and incrementally — mile…
September – October 2025 Superfund Update
CTEC Sep-Oct update Download the Update