In Montana, the 427-acre ACM Smelter and Refinery site is located adjacent to the unincorporated community of Black Eagle along the Missouri River in Cascade County. The city of Great Falls is located immediately across the river from the site.
The Boston & Montana Consolidated Copper and Silver Mining Company began construction of the first smelter at the site in 1892. Primary products from activities at the site were copper, zinc, arsenic and cadmium. Operations began in 1893, when ore from mines in Butte, Montana, was concentrated, smelted and refined.
Electrolytic and furnace refineries also operated at the site. Anaconda Copper Mining Company acquired the property in 1910. Zinc smelting and refining activities continued at the facility until the early 1970s.
The property again changed hands in 1977, when Atlantic Richfield Company (ARCO) purchased the site. Copper refining continued until the plant closed in 1980.
Eighty years of refinery operations contaminated soil, groundwater and surface water resources around the site. The refinery’s smoke stacks ejected lead, arsenic and other metals in wastes from the refinery processes.
Deposition from the stacks likely contaminated nearby residential yards. As a regular practice, tailings, smelter wastes, slag and flue dust were dumped into the Missouri River until 1915. After that, most wastes were deposited on site.
The State of Montana estimated 27.5 to 31 million tons of slag and tailings were dumped directly into the river. The Missouri River was found to be contaminated from dumping and on-site runoff and wastes have been identified more than 30 miles downstream.
After the smelter and refinery closed, ARCO initiated reclamation and maintenance activities throughout the 1980s and 1990s. In 2002, at the request of the State of Montana, EPA conducted a site investigation of the facility. An expanded site investigation was conducted in 2007/2008 within the Black Eagle community. EPA placed the ACM Smelter and Refinery on the Superfund program’s National Priority List in March 2011.
Now, on August 22, 2023, the Atlantic Richfield Company and ARCO Environmental Remediation, L.L.C. (collectively, Atlantic Richfield) have agreed to the cleanup of community soils at the ACM Smelter and Refinery Superfund Site in Black Eagle, Montana.
The U.S. Environmental Protection Agency (EPA) announced the agreement, which includes both residential and non-residential yards and soil affected by the refinery’s operations.
Under the proposed consent decree, Atlantic Richfield is required to pay for past response costs and implement a multi-million-dollar cleanup for community soils at the Site.
“This proposed consent decree between EPA and the Atlantic Richfield Company represents a new chapter in the effort to protect human health and the environment in the community of Black Eagle,” said EPA Regional Administrator KC Becker.
“I applaud those who worked diligently to obtain this agreement, which will address decades of soil contamination and provide a safer, more healthful environment for generations to come,” she added.
The former smelting and refining facility, referred to as the Great Falls Refinery, operated for nearly 80 years near the unincorporated community of Black Eagle.
The smelter and refinery’s operations produced large quantities of slag, tailings, flue dust and other smelter and refinery wastes containing lead, arsenic and other metals that contaminated soil, groundwater and surface water resources at the Site. EPA placed the Site on the Superfund National Priority List in March 2011.
The proposed consent decree requires Atlantic Richfield to implement remedial design and remedial action in the community soils portion of one of the Site’s three operable units, OU1, at an estimated cost of $2,286,000 and pay $464,475.12 for past response costs incurred by EPA through September 30, 2022.
“I am pleased that the EPA and the Atlantic Richfield Company have reached this agreement to clean up contamination from the decades-long operation of the former smelter and refinery in Black Eagle,” said U.S. Attorney Jesse Laslovich for the District of Montana.
“I am hopeful that this consent decree will restore the natural resources and lead to a healthier and safer environment for the people of Great Falls,” he continued.
“This is an exciting milestone for the cleanup in Black Eagle,” said Amy Steinmetz, waste management and remediation division administrator for the Montana Department of Environmental Quality (MDEQ).
“MDEQ looks forward to working with the EPA and Atlantic Richfield, on behalf of Montanans, as the cleanup in Black Eagle and at the former smelter and refinery site move forward,” she concluded.
The consent decree filed today in U.S. District Court in Great Falls, Montana, is subject to a 30-day public comment period and approval by the federal court. A copy of the consent decree is available on the Justice Department’s website.
Under Montana state law, the Department of Environmental Quality is separately required to put the proposed consent decree out for public comment, which will be available on DEQ’s website.
The state’s public comment period will run concurrently with the federal public comment period.
Photo courtesy of Cascade County, Montana.