OSWER/OSRTI

Washington, DC 20460

NATIONAL PRIORITIES LIST (NPL) 

***Proposed Site*** March 2015 

ANACONDA ALUMINUM COCOLUMBIA Columbia Falls, Montana

FALLS REDUCTIONPLANT Flathead County

 Site Location:

The Anaconda Aluminum Co Columbia Falls Reduction Plant (also called Columbia Falls Aluminum) is a primary 

aluminum smelting facility located in northwest Montana approximately two miles northeast of Columbia Falls, in Flathead 

County. 

 Site History:

The Anaconda Copper Mining Company built the aluminum reduction facility and began aluminum production in 1955. 

The Atlantic Richfield Company (ARCO) purchased the plant in 1978 and operated it until 1985 when it was sold to the 

Montana Aluminum Investor’s Corporation and began operations under CFAC. In 1999, Glencore acquired the company 

and operated until 2009 when production stopped due to poor economic conditions for aluminum production. The property 

boundary currently includes approximately 3,200 acres with an operational area of approximately 950 acres. The plant is 

currently not in use. 

 Site Contamination/Contaminants:

A byproduct of the aluminum reduction process is spent potliner which is known to contain cyanide and flouride 

compounds that can leach into ground water. Spent potliner material was landfilled on site from approximately 1955 to 

approximately 1985. Other landfills located at the site received various wastes throughout the lifespan of the plant, 

including air scrubber sludge, likely containing fluoride compounds. 

The ground water and percolation ponds at the site are contaminated with cyanide and fluoride, as well as other metals.

 Potential Impacts on Surrounding Community/Environment: 

Contaminants have been released into ground water beneath the site, as well as the Flathead River and Cedar Creek (both 

located directly adjacent to the site). Cyanide has contaminated two nearby residential wells. Other homes within the same 

neighborhood have domestic wells for their water source which may potentially be contaminated. Cyanide and metals, 

including fluoride and manganese are contaminating the Flathead River. The Flathead River is a fishery that supports a 

variety of fish, including the federally-designated threatened bull trout, the federally-designated sensitive westslope 

cutthroat trout and other species that are harvested for human consumption. 

 Response Activities (to date):

There have been no response activities to date.

 Need for NPL Listing:

The site needs to be placed on the NPL to clean up surface water, sediment and ground water contamination. Other federal 

and state clean up programs were evaluated but are not viable at this time. The EPA received a letter of support for placing 

this site on the NPL from the state.

[The description of the site (release) is based on information available at the time the site was evaluated with the HRS. The description may change 

as additional information is gathered on the sources and extent of contamination. See 56 FR 5600, February 11, 1991, or subsequent FR notices.]

For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these 

substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet 

at http://www.atsdr.cdc.gov/toxfaqs/index.asp or by telephone at 1-888-42-ATSDR or 1-888-422-8737.