Adak Naval Air Station sits on Adak Island in the Aleutian Islands of Alaska. The Navy operated there from the early 1940s until September 2000, and during that time disposed of hazardous materials including petroleum, chlorinated solvents, batteries, transformer oils containing polychlorinated biphenyls (PCBs), and unexploded ordnance. Those activities contaminated soil, groundwater, and sediments across the 76,000-acre site. EPA added the site to the National Priorities List in May 1994.
The site is divided into multiple operable units, which are distinct areas managed separately to make cleanup more efficient. Five contaminants of concern have been identified in soil within Operable Unit B-1. All five are explosive or munitions-related compounds: 2,4,6-trinitrotoluene, dinitrotoluene (mixed isomers), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), N-methyl-N,2,4,6-tetranitroaniline (tetryl), and nitroglycerin. Beyond ordnance-related compounds, the broader site also has contamination from petroleum and chlorinated solvents in soil and groundwater.
The U.S. Navy is the responsible party. Cleanup actions have included capping historic landfills, treating and excavating contaminated soils, treating contaminated groundwater, clearing unexploded ordnance, and putting land use controls in place. More than 20 removal actions have addressed immediate threats. Several major operable units have completed remedial actions. OU 01 finished in November 1997, OU 02 in September 2012, and OU 03 in August 2014. A removal action for OU 05 was completed in December 2023, and that unit is now undergoing a combined remedial investigation and feasibility study expected to finish between October and December 2026.
Human exposure is under control through engineered remedies and land use controls. Residents and visitors get drinking water from surface water not affected by hazardous substances. People are advised to avoid certain marine organisms in Sweeper Cove and Kuluk Bay and to stay away from unexploded ordnance. Contaminated groundwater migration is stabilized with no unacceptable discharge to surface water, and monitoring continues. Physical construction is still ongoing across parts of the site, so it is not yet ready for full anticipated reuse. A new sitewide investigation for per- and polyfluoroalkyl substances (PFAS) began in January 2024 and is estimated to conclude between June and August 2027. The final remedy for the sitewide cleanup is expected to be selected between October and December 2026.
Community members with questions can contact EPA's Community Involvement Coordinator or Remedial Project Manager. The Alaska Department of Environmental Conservation and the U.S. Navy also have representatives involved in the cleanup process.
