The Anaconda Smelter National Priority List site is located at the southern end of the Deer Lodge Valley. The site includes the former Anaconda Copper Mining Company’s ore processing facilities (above). These and other facilities were developed to remove copper from ore mined in Butte from 1884 through 1980. In 1977, the Atlantic Richfield Company (ARCO) purchased the assets of Anaconda Copper. Four years later, ARCO ceased smelting activities in Anaconda.

The Site covers about 300 square miles and includes the Old Works; Arbiter Plant; Smelter Hill; numerous piles, waste ponds, and demolition dumps. Extensive acreage contaminated by areal deposition of smelter stack emissions resulted in elevated concentrations of metals and low pH in the upper few inches of the soil. This harmed existing vegetation and limited seed germination, leaving a sparsely-vegetated easily eroded landscape.

Smelter wastes contain elevated levels of arsenic and metals (copper, cadmium, lead, and zinc) posing potential risks to human health, wildlife, and aquatic organisms. An assessment of the problems associated with the site led EPA to include it on the National Priorities List (NPL) of Superfund sites in 1983. As owner, ARCO is the potentially responsible party (PRP). This means that under the Superfund law, EPA looks to them to clean up contaminants that may cause a risk to human health and the environment.