Butte Priority Soils Operable Unit



Moving Forward

An enormous amount of environmental cleanup and reclamation work has been done in Butte-Silver Bow County, Montana, by a great many people over the last 30-plus years.

Atlantic Richfield Company’s remediation work in the Butte Priority Soils Operable Unit (BPSOU) has focused on two tasks: (i) remediation of the historic mining landscape to limit human contact with metals and to prevent mining waste from eroding into the creek corridor, and (ii) remediation in and around the creek corridor to improve water quality significantly in Silver Bow Creek.

Atlantic Richfield Company’s remediation work has been completed at the direction of US EPA after consultation with the State of Montana. Further information about the process that US EPA uses to select, construct and operate environmental remedies is available on the Legal page of this website. While we have made great progress, there is more work to be done. On April 11, 2019, the US EPA released a proposal for a modified remedy that is supported by Atlantic Richfield. On February 4, 2020, US EPA amended the remedy for the BPSOU. On February 13, 2020, US EPA, the State of Montana, the consolidated City and County government of Butte-Silver Bow (BSB) and Atlantic Richfield Company announced a proposed partial Consent Decree for the BPSOU. If the Consent Decree is approved by the BSB Commissioners and if it is also approved by the court following a period of public comment, then the following work will be performed to complete portions of the BPSOU remedy and related projects in the creek corridor.

View the History

Butte’s mining history is fascinating. To read more about our history, and better understand how we to this final remedy, take a look here. View the history.

View the Timeline

Take a look timeline to see a summary of key events and milestones in our history that have led us to where we are today. View the timeline.

Remedy work includes:

  • Remove additional mining waste from the creek corridor area.
  • Further improve water quality in Silver Bow and Blacktail creeks.
  • Prepare property owned by Atlantic Richfield and BSB to be developed as a 120-acre chain of open green space and recreational areas along the Blacktail and Silver Bow Creek corridors, integrating the remedy with community land use plans.
  • Provide funds for the State to complete a coordinated remedy and restoration project in the Blacktail Creek area.

Answering your Questions

Questions about BPSOU or the remedy? Search through the FAQ section to find answers. Contact us with your question.


How much waste is going to be removed from the creek corridor?

Current estimates suggest that over 800,000 cubic yards of waste could be removed from the corridor. Imagine filling the Finlen Hotel Tower 25 times!


Where will the waste be disposed of?

A committee, including representatives from the project stakeholders and the public, is currently evaluating potential locations to dispose of the waste. Once the committee has completed their evaluation, they will recommend a repository location to the EPA and DEQ for consideration and final approval. Regular progress updates will be given during EPA’s monthly communications call. 


When will construction begin and when will it end?

Construction activities are now expected to begin in summer 2023. Completion of the entire Silver Bow Creek Conservation Area is anticipated by 2028. A map of project locations and a calendar reflecting project progress, status, and timelines are available on the project website.


How will dust be controlled during construction?

Project contractors will be required to use proven methods to control dust. Water or other soil binder will be applied to exposed soils, truck loads will be covered when transporting waste, and contractors will clean public streets that are impacted by the hauling activities. Air quality monitoring stations will also be installed at the project sites to evaluate dust control effectiveness and support necessary changes, if needed.

Grassy Field Butte
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The Locations

Since the 1880s, Butte, Montana, has been the epicenter of copper mining in North America. During this time, the copper was shipped out but the wastes from mining and smelting activities were deposited throughout Butte and along the 26-mile Silver Bow Creek corridor. In 1983, EPA placed the Creek on the Superfund’s National Priority List (NPL) and added the Butte area in 1987. The NPL site includes 10 operable units. One of those is the Butte Priority Soils Operable Unit, or BPSOU. The BPSOU includes more than 6 square miles of the Butte Hill (over 4,000 acres).

BPSOU Resources

News & Updates

Design Investigation Along the Upper Silver Bow Creek Trail

Atlantic Richfield Company is conducting a design investigation along the upper Silver Bow Creek trail, adjacent to Harrison Avenue and the Butte Civic Center. The purpose of the investigation is to collect geotechnical data that will be used to support the design of...

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Summer 2024 Park Clean Up Notice of Temporary Closures

The Residential Metals Abatement Program (RMAP) will continue cleaning up parks and play areas throughout Butte during the summer of 2024. This work will result in temporary park closures. We thank you for your understanding and cooperation while we complete this...

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EPA Responses to Dr. John Ray’s Emails

On April 3, 2024, EPA posted responses to emails received from Dr. John Ray on February 20th and 29th, and March 1st and 6th, 2024. EPA compiled all emails and corresponding responses into one document and can be found here:...

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