Naval Air Station Whidbey Island (Seaplane Base) sits on the northern edge of Puget Sound on Whidbey Island, Washington. The Navy has operated aircraft and vehicle maintenance, painting, and machine shop activities there since the 1940s. Those operations produced hazardous wastes that contaminated soil, groundwater, and surface water across five waste areas, including a landfill, a salvage yard, and three uncontained spill sites. EPA added the site to the National Priorities List in February 1990 and deleted it in September 1995 after cleanup goals were met.
The contaminants of concern in soil at the site are arsenic, chromium, lead, two DDT compounds (P,P'-DDD and P,P'-DDT), and polycyclic aromatic hydrocarbons. In addition, perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), a class of chemicals known as PFAS, have been detected in groundwater at several areas of the site. Known off-site drinking water exposures from PFAS have been addressed, and on-site land use controls prevent people from being exposed to contaminated groundwater. A sitewide PFAS investigation is underway, with a combined remedial investigation and feasibility study estimated to finish between October and December 2027.
Cleanup of contaminated soil involved excavation and off-site disposal. Remedy construction ran from 1994 to 1995. The Navy, as the lead federal agency, is responsible for site remediation and community involvement. EPA oversees compliance with Superfund law. The site achieved sitewide readiness for anticipated reuse in September 2009, meaning all cleanup goals for current and future land uses have been met and required land use controls are in place. Portions of the base have since been converted to housing-related uses, while the Navy continues to operate aircraft and aviation facilities there.
The sixth five-year review, completed in September 2024, confirmed that cleanup actions protect public health and the environment in the short term. Continued protectiveness depends on maintaining and routinely inspecting land use controls. Human exposure to contaminated soil is currently under control, with no unacceptable exposure pathways identified.
Community members with questions can contact the EPA Remedial Project Manager or the Community Involvement Coordinator for the site. The complete Administrative Record is available through the Navy as lead agency or through the site's Public Information Repository.
