Daikin PFAS whistleblower Wada Toshiji dies, sparking Japan's first pollution mediation

Wada Toshiji, a 74‑year‑old retired engineer, died on 18 July after collapsing near his garden in Settsu, Osaka. Six years earlier he had been the first person to expose PFAS (per‑ and polyfluoroalkyl substances) contamination from Daikin Industries’ Yodogawa plant, which led to Japan’s first public‑interest pollution mediation.

Investigations revealed groundwater near the plant contained 18,366 ng of PFOA—about 360 times the Ministry of the Environment’s guideline. Wada’s own blood showed similarly high concentrations, though he exhibited no clear disease. Daikin maintains it stopped PFOA production five years ago and claims current groundwater levels are declining.

The case drew the involvement of Kyoto University professor Akio Koizumi and his student Koji Harada, who sampled soil and water, confirming the extreme contamination. After Wada’s death, his son continued the advocacy, urging local and prefectural officials to address the ongoing pollution.