Man suffered most painful death imaginable after horror accident left him in agony for 83 days

In 1999, a man reportedly begged doctors to stop treating him as he 'cried blood' and his 'skin melted' before dying a horrific death.

When it comes to the worst ways to die, being skinned alive, burning to death and drowning all sound pretty brutal.

But none of them come close to what happened to Hisashi Ouchi, however.

Ouchi was a technician at the Tokaimura Nuclear Power Plant, about 90 miles northwest of Tokyo.

In 1999, disaster struck at the power plant when three workers attempted to pour uranium into a huge metal vat.

None of the men involved in the delicate process had been properly trained to carry it out and, due to a miscalculation, the liquid reached 'critical point.'

In nuclear engineering, the critical point or critical mass refers to the smallest amount of fissile material needed for a sustained nuclear chain reaction.

Due to the men carrying out the procedure manually, they had no way of measuring how much uranium was being transferred and ended up using 16kg - a whopping 13.6kg over the limit.

This then flung dangerous neutron radiation and gamma rays into the building.

Ouchi was exposed to more radiation than the other workers, suffering burns, becoming dizzy, and violently vomiting.

But the 35-year-old's nightmare was only just getting started.

Hisashi Ouchi suffered severe radiation sickness after an accident at Tokaimura Nuclear Power Plant (Public Domain)

It was discovered that Ouchi had absorbed 17 Sieverts (sv) of radiation, which is the highest amount of radiation taken on by a single living person - around twice the amount that should kill someone.

For comparison, emergency responders at Chernobyl were exposed to just 0.25 sv.

He was rushed to the University of Tokyo Hospital, where doctors discovered that there were no white blood cells in Ouchi's body.

He was in desperate need of extensive skin grafts and multiple blood transfusions, and exposure to the dangerous substance reportedly left him 'crying blood'.

His bone marrow cells began indicating fragmentation and doctors noted that he was unable to regenerate any new cells.

And two weeks after the incident, Ouchi was no longer able to consume food and had to eat intravenously.

Ouchi died a brutal death after being exposed to the most radiation ever faced by a human being (Public Domain)

Doctors desperately tried to keep him alive, but Ouchi begged them to stop just a week into treatment.

Ouchi reportedly yelled: "I can't take it any more! I am not a guinea pig!"

However - at the request of his family - doctors continued their treatment.

But on December 21, Ouchi's body eventually gave out and died as a result of multiple organ failure - 83 days after his radiation exposure.

His supervisor, Yutaka Yokokawa, also received treatment for minor radiation sickness, before going on to face charges of negligence in October 2000.

And nuclear fuel company JCO was also forced to pay out $121 million in compensation to people and businesses who had suffered as a result of the accident.