Yushō disease

Yushō disease, whose Japanese name means oil symptoms, was a mass poisoning by polychlorinated biphenyls that occurred in northern Kyūshū, Japan, in 1968. Rice bran oil made by the Kanemi Company was contaminated with PCBs and polychlorinated dibenzofurans when leaking pipes carrying PCB heating fluid let it into the oil during deodorization. The oil was sold to poultry farmers as a feed supplement and to consumers for cooking. About 400,000 birds died, and roughly 14,000 people who ate the oil were affected, more than 500 of whom died. Common symptoms were skin and eye lesions and a weakened immune response, along with fatigue, headache, cough and unusual skin sores, and children showed poor cognitive development. An almost identical outbreak, known as Yu-cheng disease, followed in Taiwan in 1979, and animal studies of the toxins helped reduce PCB use in manufacturing.