PFAS contamination associated with aqueous film-forming foam (AFFF) use at U.S. military installations in Japan has been a significant environmental and political issue since the mid-2010s. The cases in Okinawa and Kanagawa prefectures illustrate the challenges of managing PFAS contamination in a host-nation context and have directly influenced Japan’s evolving regulatory framework.
Okinawa: Kadena Air Base and Camp Schwab Contamination
Okinawa Prefecture has documented some of the most significant PFAS contamination cases in Japan. Monitoring of rivers and groundwater downstream of Kadena Air Base — one of the largest U.S. Air Force bases in Asia — has detected PFOA and PFOS concentrations exceeding Japan’s 50 ng/L provisional target multiple times since systematic monitoring began. The Hija River, which supplies drinking water to a large portion of central Okinawa, has been a focal point of contamination monitoring and public concern.
Camp Schwab and other U.S. Marine Corps installations in northern Okinawa have also been associated with groundwater PFAS detections. The combination of AFFF historical use for aircraft rescue and fire fighting training, local geology that facilitates groundwater transport, and proximity to public water supply intakes creates a complex multi-source contamination scenario that has been difficult to characterize definitively given restricted access to base interiors for Japanese environmental sampling teams.
Kanagawa and the Broader Base Contamination Pattern
In Kanagawa Prefecture, groundwater PFAS detections near U.S. military facilities — including installations in the Zama and Sagami areas — have prompted prefectural government monitoring programs and public communication. The pattern of elevated PFAS near base perimeters, declining with distance, is consistent with AFFF as a primary source, though Japanese authorities face jurisdictional limitations in conducting on-base environmental investigations under the Status of Forces Agreement (SOFA).
The host-nation base contamination cases have driven demand for PFAS treatment capacity in the affected municipalities. Local water utilities have implemented GAC treatment upgrades and increased monitoring frequency at intake points proximate to military installations. The cases have also accelerated Japan’s national PFAS monitoring program, expanding the number of monitoring sites and detection frequency across prefectures hosting U.S. military presence.
For water treatment technology vendors, the military base contamination cases represent a discrete, well-documented market segment with clear regulatory driver and procurement urgency. Municipalities in Okinawa and Kanagawa prefectures are active buyers of PFAS monitoring equipment, treatment media, and engineering services, and public documentation of contamination events provides a strong reference market for technology providers.