Tokyo, Oct 13 (IANS): Repeated reports of chemical leaks linked with US military bases in Japan have fueled public concern over their potential health risks, prompting calls for a thorough investigation.

In the latest case, around 47,000 litres of water contaminated with per- and polyfluoroalkyl substances (PFAS) overflowed from the US Yokota Air Base in western Tokyo during heavy rainfall in August, Xinhua reported.

Tokyo metropolitan officials received the report on October 3 from the US military through Japan's Ministry of Defense, expressing "regret" over the delayed information disclosure as the incident could fuel distrust among residents living near the base.

"If the government doesn't have a system in place to inspect the base, such incidents will only happen again," commented one Japanese netizen on the news.

PFAS encompasses over 10,000 synthetic chemicals, including perfluorooctanesulfonic acid and perfluorooctanoic acids, used in products like non-stick cookware and water-resistant clothing.

In its first health assessment of the substances in June, Japan's food safety panel concluded that the effects of PFAS on birthweight loss and reduced immunity are "undeniable", even though "evidence is limited" regarding the potential of PFAS to cause cancer.

While the extent of health effects caused by PFAS is still not fully understood, a citizens' group in 2022 conducted blood tests on 650 residents of the Tama region where the Yokota Air Base is located, and among them, 55 individuals exceeded overseas standards considered indicative of health risks in terms of PFAS concentration.

Similar contamination issues have emerged in other parts of Japan, including Okinawa and Osaka, where PFAS levels in water sources near the US military and Japanese Self-Defense Force bases have exceeded limits.

The Tokyo metropolitan government has asked the Japanese government to take responsibility for investigating the matter and implement measures to prevent future occurrences.