CFAC History


Aluminum production began at the Anaconda Aluminum Reduction Works near Columbia Falls. At the time, the plant was owned by Anaconda Copper Mining Co., and initial construction consisted of two pot lines with an annual capacity of 67,500 tons.


The Anaconda Company was purchased by Atlantic Richfield Company (ARCO). ARCO sold the plant in 1985 to the Montana Aluminum Investors Corporation and announced the plant would be operated as the Columbia Falls Aluminum Company (CFAC) moving forward.


CFAC was acquired by Glencore. Glencore operated the plant during a period of evolving regulatory and economic conditions and elected to idle the facility in 2009. By the time the facility shut down permanently in 2015, CFAC was one of just 11 aluminum plants operating in the United States.


The U.S. Environmental Protection Agency (EPA) added CFAC to the National Priorities List (NPL). Sites on the NPL are often referred to as Superfund sites.

Key Milestones

November 2015

Administrative Order of Consent

EPA and CFAC agreed that CFAC would conduct a remedial investigation/feasibility study (RI/FS) in accordance with EPA guidelines to investigate the site for contamination and develop and evaluate options to address the issues.

March 2020

Remedial Investigation

Supervised by EPA and with input from the Montana Department of Environmental Quality (DEQ), CFAC used the legally required process to assess and evaluate options to address issues at the site. CFAC contracted with Roux, an independent environmental engineering firm, to conduct the RI, which was finalized and approved by EPA in March 2020. Roux conducted a fact and science based comprehensive investigation to determine the level of contamination at the site, and their analysis found that there was no impact to neighboring communities or to the main stem of the Flathead River. Roux identified two legacy onsite landfills impacting groundwater as the main environmental issue at the site.

The RI divides the site into six areas, referred to as Decision Units (DUs), for remediation.

June 2021

Feasibility Study

Once the RI was approved, Roux began to evaluate remediation options and produce the FS, which was approved by EPA on June 17, 2021. Roux used a well-established analytical method to evaluate the options for each Decision Unit in accordance with Superfund law and subsequent EPA regulations and guidance.

Roux evaluated eight options to address the landfills (Landfill Decision Unit 1) to achieve legally required groundwater quality standards. The highest ranked option was a fully-encompassing slurry wall, which is a proven and reliable method to isolate material from groundwater.

Currently in Progress

Record of Decision

EPA will use the evaluation work in the RI and the FS to select a set of preferred alternatives to remediate the site. Residents and other stakeholders will have the opportunity to comment on EPA’s preliminary plan and preferred option prior to the issuance of its Record of Decision (RoD), which will contain the final site remedy.