On Friday, Japanese authorities conducted an inspection of a U.S. military base in Tokyo after being notified of a chemical leak. The inspection was carried out at Yokota Air Base, following a report from the U.S. military about a spill of water contaminated with PFOS, a chemical compound classified by the World Health Organization (WHO) as "possibly carcinogenic to humans." The Japanese investigation was triggered by the U.S. military's notification two months earlier, which revealed that the leaked water contained perfluorooctane sulfonate (PFOS), part of a group of chemicals known as PFAS, which are often referred to as "forever chemicals" due to their resistance to breaking down in the environment.

According to Fumitoshi Sato, Japan’s deputy chief cabinet secretary, the U.S. informed Japan in October that the leak occurred in an area of the Yokota Air Base where a firefighting drill had been conducted. This water, contaminated with PFOS, was found to have spilled from the site. The Japanese government’s inspection was prompted by concerns from local residents who expressed fear over the potential risks posed by the chemicals, particularly given their classification by the WHO. The government has pledged to continue cooperating with the U.S. to address the issue.

The inspection involved officials from Japan’s defense ministry, as well as representatives from Tokyo’s metropolitan government. Together, they visited the Yokota Air Base to examine the situation and assess the potential environmental and health impact of the leak. At the time of the inspection, the Yokota Air Base had not responded to requests for comment, and the full extent of the contamination was still unclear. However, Japanese officials have emphasized their commitment to transparency and have reassured the public that the government will closely monitor the situation.

The chemical leak is the latest in a long history of local discontent surrounding the presence of U.S. military bases in Japan. Over the years, Japanese citizens, particularly those living near military installations, have raised concerns about issues ranging from noise pollution and accidents to environmental hazards such as chemical leaks. This frustration is especially evident on Okinawa, the southernmost island in Japan, which hosts the vast majority of the country’s U.S. military facilities, despite comprising just 0.6 percent of Japan’s total landmass. Okinawa’s strategic position east of Taiwan—an area of increasing geopolitical tension between the United States and China—has further complicated local attitudes toward the U.S. military presence.

The relocation of U.S. Marines from Okinawa has been an ongoing process, with a recent shift aimed at easing the burden on the island. Earlier this month, the U.S. began moving thousands of Marines from Okinawa, with the first group of approximately 100 logistics support Marines transferred to Guam, a U.S. territory. This move is part of broader efforts to restructure the U.S. military presence in the region, but it has not alleviated local concerns about the long-term environmental and social impacts of having such a heavy U.S. military footprint on Okinawa.

The chemical leak at Yokota Air Base adds to the growing list of environmental and safety concerns associated with the U.S. military’s operations in Japan, highlighting the need for continued dialogue and collaboration between the U.S. and Japanese governments to address the health and environmental risks posed by these military activities.