FAQs
Find answers to common questions about the Butte–Silver Bow Creek Superfund cleanup.
How Big is the Silver Bow Creek-Butte Area Superfund Site?
The site encompasses the Berkeley Pit and 10,000 miles of underground mine workings beneath the city of Butte and extends 26 miles down Silver Bow Creek to the 2,600 acre Warm Springs Ponds.
Is Butte’s drinking water safe?
Butte’s public water comes from three sources: the Big Hole River, Moulton Reservoir and Basin Creek Reservoir. It is treated at the Big Hole Treatment Plant and the Moulton Treatment Plant. Water quality is frequently tested and meets or exceeds all standards for drinking, cooking and bathing.
Who’s in charge of Superfund?
If you think of Superfund as an orchestra, the conductor who oversees performance is the Environmental Protection Agency (EPA). The EPA supervises a process that includes the Montana Department of Environmental Quality, the Montana Natural Resource Damage Program (NRD), Atlantic Richfield Corporation (ARCO) and its contractors, and various other players across a spectrum of ongoing projects within the seven Operable Units of the Butte/Silver Bow complex.
How much has Superfund cost?
As of 2025, cost estimates for the entire Superfund monolith which includes Butte/Silver Bow, Anaconda, and the upper Clark Fork River have totaled roughly $3 billion. The Butte/Silver Bow portion of the Superfund bill has come to roughly $400 million.
Is mining still going on in Butte?
Mining does continue in Butte, under the auspices of Montana Resources, a Dennis Washington company. Active mining is strictly monitored and takes place in the Continental Pit, adjacent to the Berkeley Pit. The current operation employs roughly 300 people and is mining for copper ore and a medley of other minerals.
Where can I get blood lead level testing?
Blood level testing is provided for free through Superfund. Contact the Residential Metals Abatement Program (RMAP) at (406) 497-5040 to schedule an appointment.
Why is the Superfund process taking so long?
The short answer is that it is really complicated and difficult. The overall site is massive, the cleanup is multi-layered, including soils, water, air, groundwater, vegetation, storm water, and more. Challenges are often gargantuan (think the Berkeley Pit, for example). Each facet of each Operable Unit goes through an exhaustive cycle of assessment, design, proposal, comment period, approval and implementation. Taken together, each discreet project can take years to complete.
Is the Berkeley Pit in danger of overflowing?
No. The Berkeley pit lake, which until 2019 was rising about 6-feet per year, is now hydrologically controlled by pumping and has remained 60 feet below the groundwater divide - the elevation at which it would flow to Silver Bow Creek.
When did the Superfund process begin?
Silver Bow Creek was designated as a superfund site in 1983, and the larger Butte area was added in 1987.
What is an Operable Unit (OU)?
Because the Superfund project is so massive and complex, the Butte/Silver Bow portion has been broken up into seven, more manageable pieces. They are Westside Soils, Butte Mine Flooding, Streamside Tailings, Rocker Timber Framing and Treating Plant, Butte Priority Soils, and two OUs at Warm Springs Ponds.
How do I get my attic insulation and soil tested for contaminants?
The Residential Metals Abatement Program (RMAP) handles free residential testing in Butte and surrounding areas, as well as the work of soil replacement and attic insulation removal and replacement. Contact them for an appointment at (406) 497-5040.
Is the Berkeley Pit in danger of overflowing?
No. The Berkeley pit is hydrologically controlled to remain at a safe level and will continue to be contained in perpetuity.