Superfund Sites in Reuse in Nevada

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ANACONDA COPPER MINE

The Anaconda Copper Mine site covers more than 3,400 acres in the Mason Valley, near Yerington, Nevada. Mining operations in the area date back to 1918. From about 1952 to 1978, Anaconda mined and milled copper on site. Mining operations generated 400 acres of waste rock, 900 acres of contaminated tailings and 300 acres of disposal ponds. In the late 1970s and early 1980s, sampling by the Nevada Division of Environmental Protection found that mining activities had contaminated area groundwater. The NDEP and EPA led several emergency removal actions, including stabilizing the leachate containment system, putting in new leachate evaporation ponds, containing groundwater, monitoring, and supplying bottled water to residents. EPA proposed adding the site to the Superfund National Priorities List in 2015. At the NDEP’s request, EPA deferred the listing in 2018 and transferred responsibility for investigations to the state. The site consists of eight areas, or operable units. EPA and the NDEP selected the final remedy for OU-8 in 2017. The NDEP is overseeing the remedial action, which is led by the site’s potentially responsible party. Cleanup planning for other parts of the site is ongoing. EPA conducted remedial investigations and risk assessments on Tribal lands near the site. The NDEP oversees all other investigation and cleanup activities. Current site uses include a historical landmark with site information and an area that overlooks the 180-acre Pit Lake, which formed after mining operations and groundwater pumping from the pit stopped. 
Last updated October 2025

As of December 2024, EPA did not have economic data related to on-site businesses, or economic data were not applicable due to site use. For additional information click here.

For more information:

• Superfund Site Profile Page

CARSON RIVER MERCURY SITE

The Carson River Mercury Superfund site covers about 330 square miles and more than 130 river miles in northwest Nevada. Contamination at the site resulted from gold and silver mining in the late 1800s. Miners used about 14 million pounds of mercury to process gold and silver ore. Over several decades, the milling process released mercury, lead and arsenic into the environment. Mercury-contaminated tailings built up in the mine and mill sites. Over time, the tailings washed into the Carson River and farther downstream to the floodplain and wetlands, causing widespread contamination. In the early 1970s, the United States Geological Survey reported high levels of mercury in the Carson River’s sediment and water. EPA added the site to the National Priorities List in 1990. EPA’s investigations found mercury in soil, sediments, fish and wildlife.   To manage the cleanup, EPA divided the site into two operable units (OUs). OU 1 includes the old mill sites and tailings. OU 2 includes the Carson River and adjacent floodplain. As part of the OU 1 remedy, EPA removed mercury-contaminated tailings from high-exposure risk areas such as parks. Cleanup included the removal of contaminated soils from five residential areas in Dayton and Silver City. EPA also restored infrastructure and landscaping disturbed by cleanup activities. EPA and the Nevada Division of Environmental Protection developed a Long-Term Sampling and Response Plan in 2006 and finalized it in 2018. The plan requires sampling and, if needed, cleanup of properties slated for residential use. It enables continued residential use on-site throughout the cleanup process. Since the 1990s, EPA and the NDEP have reviewed more than 70 property development proposals. The NDEP has also done or overseen detailed soil sampling at at least 28 residential developments. EPA and the NDEP work with developers to help prevent the spread of mercury contamination by covering or capping contaminated soils when necessary to reduce exposure. The Virginia City Historic District, where many of the historic mill sites are located, depends heavily on tourism. Areas surrounding the Carson River are mostly agricultural or recreational, although the area is experiencing rapid housing growth to support high-tech businesses along the nearby USA Parkway. EPA and the NDEP work with developers and homeowners in the affected areas to identify and prevent unacceptable risk of exposure to contamination. They coordinate closely with the counties’ building and planning departments.    OU2 includes surface water, bedded sediments, bank and lake sediments, the banks of the Carson River and adjacent floodplain soils. EPA is working on a cleanup plan for OU2. EPA and the NDEP is also doing public outreach, recommending that people not eat fish in certain areas. EPA’s Superfund Redevelopment Program collaborated with state and federal agencies and The Nature Conservancy to identify areas well suited for solar and other energy development on-site. Several parks, refuges and wildlife management areas surround the Carson River. Due to high mercury levels in fish, the Nevada State Health Division issued a health advisory to strongly recommend that people not eat fish from the Carson River from Dayton to the Lahontan Dam and from all waters in the Lahontan Valley. Catch-and-release fishing, swimming and other recreation activities are safe. In 2023, the site was among those selected by EPA to receive additional cleanup funding. With this funding, EPA is working on backlogged remedial construction projects and accelerating cleanups at NPL sites. 
Last updated October 2025

As of December 2024, EPA had data on 65 on-site businesses. These businesses employed 368 people and generated an estimated $34,129,303 in annual sales revenue. For additional information click here.

For more information:

• Renewable Energy Reuse Assessment: Carson River Mercury (PDF)
• Site Redevelopment Profile: Carson River Mercury Site (PDF)
• Superfund Site Profile Page