When the authorities requested entry to MCAS Futenma to confirm the water's PFOS level, the Marines denied the request. The authorities took water samples from a manhole outside the base shortly after. They found a combined concentration of PFOS and another PFAS compound (PFOA) measuring 0.67 µg/L, which was 13 times higher than Japan's national safe drinking water threshold (0.05 µg/L). Residents living around MCAS Futenma have protested, and Okinawa authorities have objected to the Marines' actions. Japan only has national water quality safety guidelines for PFOS levels in rivers and drinking water, but no safety standards for PFAS discharged into sewers. Because of the high levels of PFAS detected on or near MCAS Futenma and other bases, Okinawans and U.S. military personnel now face a grave concern that the U.S. military's storage and use of fire-fighting foam have contaminated Okinawa's drinking water and the environment.
PFAS comprise more than 4,000 synthetic chemicals used in industry and consumer products in the United States and worldwide for more than 70 years. In the late 1960s, the U.S. military's use of PFAS increased, following a catastrophic fire on the aircraft carrier, U.S.S. Forrestal. Soon after, the U.S. military and industry developed a PFAS-containing aqueous film-forming foam (AFFF) that could successfully extinguish large petroleum and flammable-liquid fires. The Pentagon deployed AFFF on U.S. military ships, fuel storage areas, and bases at home and abroad.
PFAS can enter the environment and migrate during their production and use. They commonly seep into groundwater that becomes drinking water through improper AFFF storage and uses at airports and military bases, wastewater processing that produces biosolids applied to farmland as fertilizer, discharge and runoff of industrial waste, and consumer products discarded in unlined landfills. PFAS also persist in the environment. Human and animal exposure may occur through accumulation in the food chain. Researchers have found PFAS in agricultural plants and the tissues and organs of farm animals, pets, and other terrestrial and aquatic organisms in and around Japan like the Japanese sparrowhawk (Accipiter gularis) and Dall’s porpoise (Phocoenoides dalli). Although more research is needed to conclusively link PFAS to adverse health effects in humans and animals, studies have shown that PFOS and PFOA may lead to a high risk of cancer, liver and kidney disease, reproductive and developmental damage, and other medical disorders.
News of Okinawa main island's PFAS contamination began in 2016 when Okinawa authorities measured elevated PFAS levels in water samples taken from rivers and streams running through another U.S. base, the Kadena Air Base. Okinawa authorities conducted several follow-up tests that repeatedly showed high levels of PFAS in waterways, soil, and drinking water provided to the island’s residents. Tests near MCAS Futenma also indicated that wells and springs had high levels of PFAS. Moreover, in 2019, Kyoto University researchers conducted blood tests of residents living around MCAS Futenma. The PFOS concentration in residents' blood was four times the national average, at 13.9 nanograms per milliliter (ng/mL). These surveys strongly indicated that two significant sources of PFAS contamination were MCAS Futenma and the Kadena Air Base. Investigators concluded that Okinawans became exposed to PFAS contamination through three pathways: on-base fire-fighting training, accidental spills of AFFF, and improper disposal of AFFF. The U.S. military generally does not grant Okinawa and Japanese authorities' requests for on-base access to conduct investigations and denies responsibility for any contamination.