Editorial: US military's toxic water dump in Okinawa an assault on mutual trust

The United States is seriously violating the trust of the Japanese government as well as the people and local bodies around U.S. military bases in this country.

The U.S. Marines have been dumping water containing the toxic substances perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) kept at their Air Station Futenma base in Ginowan, Okinawa Prefecture, directly into the public sewer system after reducing the compounds' concentration.

PFOS and PFOA are not easily broken down in nature, and thus can accumulate in animals. International organizations consider PFOA a possible carcinogen, while animal research suggests that PFOS also impacts health.

The contaminated water is apparently the biproduct of firefighting drills at the air station using firefighting foam which contains the chemical substances. Japan's Environment Ministry has rules on disposing of waste containing PFOS by breaking the chemical down, such as by incineration. Until recently, the U.S. military in Japan had followed those rules, hiring a contractor to burn the waste.

However, this time it was different. The U.S. military has stated that, due to heavy rains and other reasons, the on-base storage tanks where the contaminated water was being kept were in danger of overflowing and that they needed to dispose of the water quickly. Furthermore, dumping the water is apparently cheaper and less time consuming than incineration after processing. The U.S. has also emphasized that the concentration per liter of PFOS and other substance is well below Japanese government limits for tap water, and that there is no danger.

However, when Ginowan municipal authorities tested the wastewater emanating from the Marine air base after the contaminated water was dumped, it found levels of the chemicals 13 times higher than the legal maximum. U.S. Forces should investigate what happened, and explain it.

There were also numerous problems with the process leading up to the discharge. Okinawa Prefecture did not learn of the Marines' intentions until July, and demanded the chemicals be incinerated as usual. The Marines then dumped the water unilaterally, even as the Japanese and U.S. governments were in talks on how to deal with the issue.

The U.S. informed Japanese authorities that the discharge was going ahead just 30 minutes before it happened. Okinawa Prefecture again demanded it be stopped, but some 64,000 liters of contaminated water were dumped into the sewer system, just as the U.S. military had been planning.

This was an act of bad faith that ignored every request from the Japanese side. The decision-making process within the U.S. military must be brought to light.

Last year, there was also an accidental release of firefighting foam containing PFOS outside Futenma Air Station. In June this year, there was a contaminated water leak from a storage tank at a U.S. military facility in Uruma, Okinawa Prefecture. U.S. information sharing and explanations regarding the incidents were half-hearted at best. This is deepening locals' distrust of the American forces based in their midst.

The stable operation of U.S. bases in Japan, and indeed the Japan-U.S. alliance, cannot continue in the absence of trust. We call on the U.S. military to understand that it is, by its own conduct, undermining the foundations of its presence in Japan.