EPA Superfund Site

CASTLE AIR FORCE BASE (6 AREAS)

CA | EPA ID CA3570024551

About this site’s exposure pathways: As of December 2024, there is insufficient information to determine the site-wide human exposure arising from the emerging contaminate Per- and Polyfluoroalkyl Substances (PFAS) at the Castle Air Force Base site. The site was previously categorized as human exposure under control through various pump and treat technologies currently in operation, along with institutional controls. EPA uses this Human Exposure status when there is a lack of evidence to suggest that actual or reasonably anticipated human exposures are occurring and that those exposures are above acceptable risk-based levels. The Air Force is providing water supply to residences that have been impacted by PFAS, specifically perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), that EPA has established health advisories for. A Remedial Investigation (RI) & subsequent Feasibility Study (FS) will be conducted by the Air Force to determine nature and extents of this contamination. Phase 1 of the RI work is ongoing. Future RI work will be based on initial results and findings. Once the RI is completed, a human and ecological risk assessment will be conducted to determine impacts to human health and the environment. As the Air Force being the lead, EPA and California state partners provide oversight throughout the remedial process as members of the Base Re-Alignment and Closure (BRAC) team, which includes participating in various team meetings and review of work plans and reports.