Naval Undersea Warfare Station (4 Areas)

Overview

Naval Base Kitsap Keyport is a 340-acre federal facility in Kitsap County, Washington. The Navy has used the site since 1913 for torpedo testing and undersea weapons manufacturing. Those activities contaminated soil, sediment, and groundwater with hazardous chemicals. The site was listed on the National Priorities List in October 1989 and is divided into four operable units for cleanup management.

Contamination falls into two main areas. Area 1 Landfill contains chlorinated solvents such as trichloroethene, tetrachloroethene, and vinyl chloride in groundwater, surface water, and air, along with polychlorinated biphenyl (PCB) compounds in groundwater, surface water, and sediment. Areas 2, 3, 5, 8, and 9 contain chlorinated solvents and heavy metals including arsenic, lead, mercury, and chromium in groundwater and soil, polycyclic aromatic hydrocarbons in soil, and phthalates, phenol, cyanide, and zinc in sediment. Ongoing investigations are also examining per- and polyfluoroalkyl substances (PFAS) across the site.

The U.S. Navy leads cleanup under a Federal Facilities Agreement signed in 1990, with oversight from the EPA and Washington State Department of Ecology. Cleanup plans were signed in 1994 and 1998. Work included demolishing a plating shop, removing contaminated soil and sediment, removing underground storage tanks, and treating landfill soil through phytoremediation. Main construction finished in 2000. A removal action at Area 1 Landfill occurred in 1992, and operation and maintenance activities have continued since late 1999 and early 2000 across the site.

In the 2020 five-year review, EPA found the cleanup was not protective. Specific concerns included unacceptable risk to shellfish in one area and possible exposure pathways elsewhere. Contaminated groundwater continues to spread beyond the original area, and human exposure status has not yet been determined due to insufficient data. Supplemental remedial investigations are underway in Areas 1 and 2 through 9, and a remedial investigation for PFAS contamination is estimated to begin between October and December 2026. The most recent five-year review was completed on December 15, 2025. The site has not been deleted from the National Priorities List.

The Navy started its sixth five-year review in 2024. A Notice of Completion was expected in local newspapers by the end of 2025, with the final report posted on the Navy website. Community members with questions can contact the EPA Community Involvement Coordinator or the Remedial Project Manager.