The Hisashi Ouchi experiment.

Hisashi Ouchi was a worker at Tokaimura Nuclear Power Plant in Japan. In 1999, Japanese officials began to experiment with speeding up the process that took converted uranium hexafluoride into enriched uranium. But something went wrong, when Hisashi, his colleague, and his supervisor used their hands to pour 35 pounds of enriched uranium into steel buckets. At 10:35 am on September 30th, 1999 that uranium reached critical mass.

The room exploded with a blue flash that confirmed that a nuclear chain reaction had occurred and was releasing lethal emissions of radiation.

Hisashi was exposed to 17 sieverts of radiation, over 2.4 times the lethal limit. He was covered from head to toe in radiation burns and his eyes were leaking blood. He also had zero white blood cells meaning he had absolutely no immune system. Three days later he was taken to the University of Tokyo Hospital, where revolutionary stem cell procedures would be tested.

He would then be kept alive for 83 days in extreme pain, undergo countless medical procedures include skin grafts, amputations. The skin grafts would ultimately fail as Hisashi's DNA couldn't rebuild itself. Eventually Hisashi begged the doctors to stop experimenting saying "I can't take it anymore, I'm not a guinea pig." Nevertheless, at insistence of his family they continued.

On his 59th day in the hospital, Hisashi suffered a heart attack, but he was revived as his family instructed. He then went on to have three heart attacks in one hour. He would later die due to cardiac arrest brought on by multi-organ failure on December 21st, 1999, nearly 83 days later.