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Hazardous Waste Cleanup: Solvay Silver Bow Plant in Butte, Montana

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The Solvay plant (facility) was constructed in the early 1950s to produce elemental phosphorus using an electric arc furnace method. In 1997, processing was terminated at the facility. In 2004, the facility began corrective action activities under the Resource Conservation and Recovery Act (RCRA) to address contamination at the site as a result of facility operations.

Cleanup Status

In April 2004, EPA and Solvay entered into a corrective action order on consent that required Solvay to undertake comprehensive facility-wide remedial investigations and appropriate cleanup actions. Solvay completed a RCRA Facility Investigation Report (RFI Report) that was approved by EPA in consultation with the Montana Department of Environmental Quality on June 7, 2013. Solvay also conducted investigations prior to the RFI Report that are summarized in a Current Conditions/Release Assessment Report. Solvay has submitted a Human Health Risk Assessment and an Ecological Risk Assessment that is currently under review by EPA. Groundwater is monitored on a semiannual basis for the presence of hazardous substances.

In June 2017, EPA approved a remedy for the clarifier sludge and the designation of a Corrective Action Management Unit at the facility. Solvay had proposed the remedy to address certain wastes at the facility identified in an administrative order issued by EPA that required Rhodia Inc., and its corporate successor Solvay, to undertake certain immediate and interim actions to address a number of wastes at the facility that contained elemental phosphorus. With the exception of addressing the clarifier sludge, all actions for phosphorus-containing wastes have been completed. Details of the completed actions can be found in the Waste Plan.

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Site Description

Interactive Map of the Solvay Silver Bow Plant in Butte, Montana

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Solvay’s former elemental phosphorus production plant occupies approximately 1.25 square miles in Silver Bow County, Montana. German Gulch Road crosses the northern boundary of the facility and the remaining property is bounded by industrial and agricultural lands. The facility is located west of the Continental Divide and northeast of the Pioneer Mountains. The site topography is influenced by its proximity to Silver Bow Creek and varies in elevation from approximately 5,310 feet to 5,480 feet above mean sea level at the top of the slag pile. Additional information about the cleanup can also be found in the RCRA Corrective Action Site Progress Profile.

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Contaminants at this Facility

  • Contaminants identified in the groundwater above screening levels: Arsenic, Cadmium, Chloride, Fluoride, Iron, Lead, Manganese, Mercury, Elemental Phosphorus, Radionuclides (gross alpha, Radium-226, Radium-228), Selenium, Sulfate, Thallium and Uranium.
  • Contaminants identified in the surface water above screening levels: Arsenic, Cadmium and Selenium.
  • Contaminants identified in the sediment above screening levels: Arsenic, Cadmium, Copper and Mercury.
  • Contaminants identified in the soils above screening levels: Antimony, Arsenic, Cadmium, Chromium, Lead, Nickel, Selenium, Silver, Thallium, Vanadium, and Radionuclides (Pb-210, K-40, Ra-226, U-235, gamma radiation).

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Institutional and Engineering Controls at this Facility

No Institutional Controls have been established for the site.

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Land Reuse Information at this Facility

Rocket engine testing is currently taking place at the site.

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Site Responsibility at this Facility

RCRA Corrective Action activities are being conducted under the direction of EPA Region 8 with assistance from the Montana Department of Environmental Quality.

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Site Documents

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