Chemical Leaks Linked to U.S. Bases Leave Japan Grappling for a Solution

Yomiuri Shimbun file photo
The Defense Ministry in Tokyo

High levels of a group of chemicals that repel water and oil and resist heat have been detected in water at U.S. military bases in Japan and in areas around the bases multiple times, putting the Japanese government in a bind.

Known as per-and polyfluoroalkyl substances (PFAS), the chemicals are feared to be carcinogenic, raising health concerns among people who live near such facilities.

“Local residents should not have to feel concerned [about such things],” Chief Cabinet Secretary Hirokazu Matsuno said at a press conference on Friday.

“The government will take necessary measures in cooperation with relevant ministries, agencies and local governments.”

PFAS levels above government safety standards were detected last year in wastewater at the U.S. Yokosuka Naval Base and Atsugi Air Base, both in Kanagawa Prefecture.

A leak of foam fire extinguishing agent containing PFAS after heavy rains is believed to be one of the causes.

This month, the Defense Ministry revealed that there had also been three cases of fire extinguishing agent leaks at Yokota Air Base in Tokyo between 2010 and 2012.

PFAS chemicals, which are difficult to break down naturally, are widely used in foam fire extinguishing agents and antireflective agents for semiconductors because they repel water and oil and resist heat.

There are concerns that exposure to certain PFAS chemicals could have an adverse effect on human health.

In 2015, the Japanese and U.S. governments concluded an Agreement on Cooperation in the Field of Environmental Stewardship Relating to the United States Armed Forces in Japan.

The agreement, which is supplementary to the Japan-U.S. Status of Forces Agreement, made it possible for Japan to carry out on-site inspections at U.S. bases in the event of suspected environmental pollution, but the U.S. side can exercise a certain level of discretion regarding notifications of such occurrences.

The U.S. side notified Japan about the Yokosuka and Atsugi leaks in accordance with the 2015 agreement, and the Environment Ministry and others conducted on-site inspections to confirm that the spill had been properly cleaned up after the accidents.

The U.S. side did not initially disclose the Yokota case because it claimed the chemicals did not leak outside the base.

However, high PFAS levels were detected in wells and other water sources outside the base, raising suspicions that the base was the source of the contamination.

On June 15, U.S. Forces Japan announced that extinguishing agents had been replaced with ones that do not contain PFAS at most U.S. military facilities in the country.

According to the Defense Ministry, Yokota and two other U.S. military facilities are the only remaining sites using fire extinguishing agents containing PFAS, and they are scheduled to replace the agents with PFAS-free foam by September next year.

Regarding the possibility of on-site inspections, Defense Minister Yasukazu Hamada said Tuesday, “If a specific request is made by a local government, we would like to approach the U.S. side.”

However, Tokyo Gov. Yuriko Koike said at a press conference Friday: “The government has not disclosed information necessary to make a request for an inspection, such as the location and size of the leak. The government’s response is half-hearted.”