By Mika Kuniyoshi
[On April 10] about 143,000 liters of foam extinguisher leaked from the U.S. Marine Corps Air Station Futenma (Ginowan City, Okinawa Prefecture) into the neighboring residential area. The incident is of increasing concern to residents because the foam is thought to contain a carcinogenic substance. The Japanese government and the U.S. military have handled the incident differently from usual [but issues remain].
Fire-extinguishing foam leaked into residential area
In the evening of April 10, small children playing on the grounds of the Dai-ni Satsuki Kodomo-en, a certified children center, noticed white foam floating in the air. School principal Mineko Yonaha (55) immediately associated the foam with the U.S. base 40 meters away. She told the children not to touch it. “You don’t know what might be in it,” she cautioned.
Several hours later, she was told that the foam was a fire-extinguishing agent containing perfluorooctanesulfonic acid (PFOS) and that it had leaked from the base. “I warned the kids, but I still can’t believe that something that might really be harmful entered our grounds.”
The foam covered the children’s center itself as well as the playground equipment. The center cordoned off the sandbox and changed the sand.
According to the U.S. military, a total of about 227,000 liters of foam extinguisher was spilled. Of this, about 143,000 liters (715 drum cans’ worth) could not be collected and leaked from the base into the surrounding area. The U.S. military is reportedly investigating the cause of the incident.
Local firefighters cleaned up the foam
Since around the year 2000, many countries have started to ban in principle the manufacture and use of PFOS because it harms humans and ecosystems. Much remains unknown about PFOS, however, including the long-term effects of the substance on the human body. It was the local firefighters who were called upon to clean up this toxic foam.
On April 11, the day after the children noticed the foam, local firefighters responded to calls from residents and rushed to the scene at around 8:00 a.m. to find a large amount of the foam floating on the river and over the road. Donning gloves and tall boots, they started scooping up the foam from the river in buckets. Despite spending more than six hours, they were only able to remove about 250 to 300 liters, and that figure includes water from the river.
U.S. military personnel arrived at the scene in the early afternoon that day. According to Ginowan City, the service members did not join the Japanese firefighters in the cleanup of the residential area but left the scene saying that their priority was to clean up the base.
Who is responsible for cleaning up toxic substances that leak from U.S. military bases? And what cleanup procedures should be followed? No rules have been set between the two countries. Locals, however, recall past incidents, which involved U.S. military aircraft. When an aircraft crashed, the U.S. personnel would rush to the scene to cordon off the area, and they would deny access to Japanese police and firefighters. The U.S. military would take the aircraft and the soil around the area back to the base and not allow the prefectural police to perform an onsite investigation. Locals have witnessed this kind of thing many times. Noticing the difference in the way the recent incident was being handled, a senior prefectural government official wondered, “What was it about this time?”
Permission to investigate granted speedily
Identifying the cause of the leakage and determining the extent of contamination will be the focus of the investigation. Under the Japan-U.S. Status of Forces Agreement (SOFA) and other rules between the two governments, Japanese officials need the permission of the U.S. military to enter the base and perform an investigation. This time, the permission was issued with unusual speed. The Japanese officials were allowed to collect water samples; however, the U.S. side did not agree to the collection of soil samples. The soil is now being dug up and replaced.
One of the characteristics of PFOS is that it does not easily breakdown in nature, meaning it could contaminate groundwater for many years. Kyoto University assistant professor Koji Harada, a specialist in environmental safety, has been involved in studies on the effects of PFOS and other toxic substances on Japan’s rivers. He says, “To know what kind of impact we should expect to see from this leakage, it is crucial that we thoroughly investigate where the foam extinguisher was used and how it leaked out. We need to study the original source of contamination. We need to examine the soil at the base.”