Kaiser Aluminum operated a large aluminum reduction facility on about 240 acres near Mead, Washington for over 50 years. Waste handling practices at the plant sent cyanide and fluoride into the Spokane-Rathdrum Prairie Aquifer and the Little Spokane River. The contamination plume sits 145 feet underground, runs 800 to 1,500 feet wide, and travels roughly 2.5 miles before discharging into the river through springs. Sampling in 1978 first detected cyanide and fluoride in private drinking water wells northwest of the site. EPA added the site to the National Priorities List in September 1983.
Both cyanide and fluoride have been found in groundwater, soil, and surface water at the site. EPA determined these contaminants pose an unacceptable risk to human health and the environment based on the amounts present, the types of exposure possible, and their potential health effects. The main risk pathways involve people ingesting or touching contaminated soil, groundwater, or leachate.
Early actions included providing alternate water supplies to residents with contaminated wells, restricting new well construction in the area, and capping on-site waste with asphalt to reduce further leaching. The final cleanup remedy, selected in May 2002, calls for consolidation and capping of contaminated soil, sewer line repairs, groundwater extraction and treatment, institutional controls, and long-term monitoring. The pump and treat system captures contaminated groundwater, removes cyanide and fluoride, and filters the treated water back into the aquifer. That system was designed and constructed in 2019 and 2020. Kaiser Aluminum declared bankruptcy in 2004, and a Public Custodial Trust took ownership through the bankruptcy process. The Trust sold the property in 2012, and a developer plans to redevelop it as an industrial complex.
Cleanup is ongoing and construction is not yet complete. Groundwater contamination levels have not declined as quickly as expected, and EPA has confirmed that contaminated groundwater is still migrating and has not been stabilized. Human exposure data is also still insufficient to confirm whether people face unacceptable exposure risks. No one is currently drinking the contaminated groundwater, so there is no immediate risk to people. The Washington Department of Ecology leads the site as the State-Lead National Priorities List manager. Parts of the site may be suitable for reuse, but the site does not yet meet the criteria for a sitewide Ready for Anticipated Use designation.
Community members can get more information from EPA Remedial Project Manager Diedre Lloyd or Community Involvement Coordinator Beth Clemons. The Washington Department of Ecology also maintains a dedicated webpage for the Kaiser Mead cleanup project and keeps site documents available online and at their Industrial Section office in Lacey.
