O LEM /OSRTI

Washington, DC 20460



## N ATIONAL 

## P RIORITIES 

## L IST 

## (NPL)

*** NPL Site*** September 2016



### ANACONDA ALUMINUM CO COLUMBIA Columbia Falls, Montana

FALLS REDUCTION PLANT 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. 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

. These compounds 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 been detected in two nearby residential wells. Other homes within the

same neighborhood use domestic wells for their water source which may be at risk

. Cyanide and metals, including

fluoride and manganese

, have migrated from the site and have been detected in 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):** 

Since proposal, the site owner, Columbia Falls Aluminum Company, has begun a Remedial Investigation at the site,

pursuant to an Administrative Order on Consent with EPA

. Ongoing site characterization includes soil, surface water

and sediment sampling and installation of 44 ground water monitoring well s for fu ture sampling

.

 **Need for**  **NPL Listing:** 

Previous ly collected data indicates the site warrants additio nal investigation and possible remediation of source areas,

surface water, sediment and ground water. Other federal and state cleanup programs were evaluated but are not viable at

this time. While the site owner has agreed to complete a Remedial Investigation and Feasibility Study, a t this time, no party has committed

in a legally binding agreement to implement a remedy at this site. Add itionally, no party has provided financial assurance to ensure a remedy

can be implemented. The site needs to be placed on the NPL to ensure a remedy is implemented. The EPA received a letter of support

for placing this site on the NPL from Montana’s Gover nor

.

[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

- 800

- CDC

- INFO or 1

- 800

- 232

- 4636.