Hisashi Ouchi, a 35-year-old nuclear plant worker, suffered a catastrophic and excruciatingly painful death due to an accidental release of radiation when his coworkers improperly handled uranium at the plant on September 30, 1999. This horrifying event unfolded after an excessive amount of uranium was mistakenly added to a processing tank, causing an uncontrolled nuclear reaction that exposed Ouchi to an unprecedented dose of radiation, measured at 17,000 millisieverts, far exceeding the acceptable safety limits for nuclear workers.

The incident has drawn significant attention not only due to the severity of Ouchi's suffering but also because it highlights severe lapses in safety protocols within the nuclear industry. Ouchi's radiation exposure was approximately 850 times the annual safe limit for workers and 140 times the levels experienced by residents in Chernobyl during its infamous disaster in 1986. This incident reinforced the importance of stringent safety measures and training to prevent such tragic outcomes in the nuclear energy sector.

Ouchi's final moments were described as agonizing; he experienced extensive physical deterioration and distress that led to a conversation about the most painful deaths ever recorded. His story serves as a grim reminder of the potential dangers inherent in nuclear power plants and the critical need for rigorous safety standards and emergency preparedness to protect workers from similar fates in the future.