Yokota Air Base is home to the 374th Airlift Wing, 5th Air Force and U.S. Forces Japan in western Tokyo. (Seth Robson/Stars and Stripes)
YOKOTA AIR BASE, Japan — The Air Force plans to discharge treated water containing reduced levels of PFAS — a contaminant found in firefighting foam — into storm drains near its airlift hub in western Tokyo, Japanese officials said.
The plan was announced Thursday in a news release from the Tokyo Metropolitan Government, citing information from Japan’s Ministry of Defense
In August, a short burst of heavy rain caused approximately 12,640 gallons of water to overflow from a fire training area at Yokota and onto an asphalt surface and eventually into stormwater drains. The water likely contained residual amounts of aqueous film forming foam, base officials said.
The firefighting foam contained PFAS, a class of chemicals with suspected toxic properties. U.S. Forces Japan announced in November that the U.S. military had destroyed its last supplies of toxic firefighting foam at installations in the country.
PFAS — and its components PFOS and PFOA — are also found in many household products, from stainproof and waterproof fabrics to nonstick cookware, according to the American Cancer Society. The chemicals have been linked to an increased risk of tumors in the liver, testicles, breasts and pancreas.
Japan’s Defense Ministry on Wednesday informed Tokyo about the U.S. military’s plan to remove PFAS from water in a reservoir at Yokota using a granular activated carbon filter, according to the metropolitan government’s release.
The treated water will be tested before it is discharged into stormwater drains. Water containing less than 50 nanograms of PFAS per liter — the Japanese government’s provisional target level — can be released, the release said.
The same type of filter was used to treat contaminated water at Naval Air Facility Atsugi, a U.S. base in nearby Kanagawa prefecture, in October 2022, according to the release.
Japanese officials did not provide a date for the planned discharge at Yokota but said, “as the rainy season approaches, the project is being addressed with a sense of urgency.”
The 374th Airlift Wing at Yokota did not respond to requests for comment on Friday and Monday.
