Superfund Information Systems: Site Profile

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The 300-square-mile Anaconda Co. Smelter site is located at the southern end of the Deer Lodge Valley in Montana, at and near the location of the former Anaconda Copper Mining Company ore processing facilities.

In 1884, ACM and its predecessors started large copper concentrating and smelting operations at the area presently known as the Old Works. The Old Works was located on the north side of Warm Springs Creek next to the town of Anaconda and operated until about 1901.

Around 1902, ore processing and smelting operations began at the Washoe Reduction Works (also called the Anaconda Smelter, the Washoe Smelter, the New Works, and the Anaconda Reduction Works) on Smelter Hill, south of the Old Works and east of Anaconda.

In 1977, Atlantic Richfield Company purchased the Anaconda Co. Smelter. Operations at the Anaconda Smelter ceased in 1980 and the smelter facilities were dismantled soon thereafter.
Over a century of milling and smelting operations, high concentrations of arsenic, lead, copper, cadmium, and zinc were produced. These wastes contaminated soil, groundwater and surface water with hazardous chemicals.

In September 1983, EPA placed the Anaconda Co. Smelter site on the Superfund program’s National Priorities List to address the contamination. EPA is the lead agency with Atlantic Richfield Co. conducting site activities through administrative orders.

Cleanup is complete at several areas within the site. At these areas, operation and maintenance activities are ongoing. Cleanup is underway at the remaining areas. Remedies that have been completed are currently protective of human health and the environment. Where remedies are not complete, access is controlled to prevent human exposure to waste.

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What Has Been Done to Clean Up the Site?

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Remedies completed to date are currently protective of human health and the environment. Where remedies are not complete, access is controlled to prevent human exposure to waste.

In 2015, EPA completed the fifth five-year review (PDF) (255 pp, 63.5 MB) of cleanup actions at the Anaconda Smelter site. Five-year reviews evaluate the implementation and performance of the remedy to determine whether it remains protective of human health and the environment.

The fifth five-year review identified several key issues that could potentially effect long-term protectiveness such as the need to implement and fund long-term local programs and long-term operation and maintenance plans. A fact sheet (PDF) (2 pp, 1.2 MB) is available that provides an overview of the five-year review.

Work completed at the site includes:

  • Nearly 1,000 residential and commercial properties have been cleaned up and another 1,000 are scheduled to be completed over the next several years.
  • All domestic wells and/or water supplies have been tested and/or remediated within the site. Wells are sampled/treated on a continuing basis.
  • Over 3 million cubic yards of waste have been removed from the community and consolidated onto Atlantic Richfield Co. property.
  • Over 5,000 acers of the former smelter facility and disposal areas have been capped and revegetated.
  • Nearly 1,000 acers of new wetlands have been constructed and another 5,000 acers protected.
  • Over 12,000 acres of adjacent contaminated soils have been reclaimed and support wildlife and grazing lands.
  • 140,000 feet of stormwater controls have been placed to reduce contaminated sediments from impacting streams.
  • 30,000 feet of stream have been restored, providing for a high-quality fishery.

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What Is the Current Site Status?

The site consists of multiple areas, referred to by EPA as operable units (OUs).

OU15, Mill Creek: The remedy (PDF) (199 pp, 9.4 MB), selected in 1987, included permanently relocating all Mill Creek residents, removing demolition debris and contaminated soils for later disposal, regrading and replanting areas disturbed by relocation/demolition activities, monitoring and maintaining the vegetation, and controlling access to the area. Construction of the remedy finished in late 1988. Operation and maintenance activities are ongoing.

OU11, Flue Dust: The remedy (PDF) (268 pp, 13 MB), selected in 1991, included stabilization of about 316,500 cubic yards of flue dust, placement of the treated materials in an engineered repository, long-term maintenance and monitoring, and institutional controls. The remedy required that the repository include a liner, leak detection and collection system, groundwater monitoring wells, and a cap. Construction of the remedy finished in September 1996. Operation and maintenance activities are ongoing.

OU7, Old Works/East Anaconda Development Area: The remedy (PDF) (276 pp, 11 MB), selected in 1994, included placement of engineered covers over waste, treatment of soils, surface water controls, upgrades or repairs to streambank levees, replacement or repairs to bridges, institutional controls, long-term monitoring and preservation of historic features. OU7 consists of six subareas. Construction is complete at five of the six areas. Construction at the sixth area, the Industrial Area, is nearly complete.

OU16, Community Soils: The remedy (PDF) (210 pp, 83 MB), for residential soils, selected in 1996, included removal of arsenic-contaminated soils. This remedy also called for the cleanup of future residential soils through institutional controls. The remedy for commercial/industrial areas and the active railroad area included placement of engineered covers. Construction activities were completed in 2010.

  • The 2013 modification to the Community Soils remedy (PDF) (45 pp, 2.4 MB) included cleanup of lead-contaminated residential soil, expanding the institutional controls program and development of an interior dust abatement program. Implementation of this remedy began in 2015 and is ongoing.
  • In May 2017, EPA signed an Explanation of Significant Differences (PDF) (7 pp, 3.8 MB) that addressed primary sources of interior dust contamination through sampling and cleanup. It also called for removal of arsenic-contaminated soils in gardens to a maximum depth of 24 inches and 12 inches for other areas of a residential yard.

OU4, Anaconda Regional Water, Waste and Soil: The remedy (PDF) (825 pp, 175 MB), selected in 1998 and modified in 2011 (PDF) (251 pp, 4.7 MB), included consolidation of miscellaneous waste materials, placement of engineered covers over waste management areas, treatment of contaminated soils, storm water controls and institutional controls, including the monitoring and regulation of domestic wells in groundwater areas. A Technical Impracticality Waiver for arsenic in groundwater has been applied to large areas of the site. The OU consists of 15 subareas. Remedial action is ongoing at most of the subareas. Over 10,000 acres have been remediated to date. Construction is expected to be completed over the next 10 years.

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Sampling and Monitoring

Sampling of residential properties for lead is ongoing. Yards previously tested and/or cleaned up for arsenic will also be evaluated for lead contamination. Interior and attic dust and the condition of exterior lead paint will also be evaluated during sampling. Additional sampling may also be conducted by request of landowner.

Sampling of school properties and parks will be conducted in 2018. Domestic wells will continue to be monitored and provided treatment if necessary.

Ground and surface water is routinely monitored to ensure water quality standards are met. Vegetative covers are monitored to ensure protectiveness of wildlife habitat.

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