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The Story Of Hisashi Ouchi: The World's Most Radioactive Man Kept Alive Against His Will For 83 Days

Hisashi Ouchi was 35-years-old when he was involved in a horrific accident at the Tokaimura nuclear plant in Japan. His radiation poisoning led to him suffering in agony for 83 days while doctors carried out experimental treatment on him.


Hisashi Ouchi suffered a horrendous ordeal during his 83 days as the most radioactive man in history
Hisashi Ouchi suffered a horrendous ordeal during his 83 days as the most radioactive man in history

Following a horrific accident in 1999 at the Tokaimura nuclear power plant in Japan, Hisashi Ouchi lost almost all of his skin and even began to cry blood before his agonizing death.


When Hisashi Ouchi arrived at the University of Tokyo Hospital the doctors were all left completely stunned, he had been exposed to the highest level of radiation of any human throughout history.

Ouchi was a 35-year-old nuclear power plant technician, and upon his admission to hospital he had almost no white blood cells, meaning no immune system. It wasn't long before the young man was crying blood while his skin melted.


The accident began around noon on September 30, 1999, at the Tokaimura nuclear power plant in Japan. Under pressure to meet a deadline, the Japan Nuclear Fuel Conversion Co. (JCO) disregarded all safety protocols and instructed Ouchi and two other colleagues to mix a new batch of fuel.


All three of the men were untrained in the process and began mixing the material by hand. Then, they accidentally poured seven times the amount of uranium into an improper tank. Hisashi Ouchi was stood directly over the vessel while Gamma rays flooded the room. Although the plant and the surrounding villages were evacuated, the horrific experiences of Hisashi Ouchi were only just beginning.


During his awful ordeal, Ouchi was kept in a special radiation ward that was designed to protect him from hospital-borne pathogens, while leaking bodily fluids and constantly crying for his mother. Ouchi suffered regular heart attacks but was constantly revived at the insistence of his family. His escape from his unbearable pain and suffering would not come until 83 days later when he suffered a final, and fatal, cardiac arrest.

The Story Of Hisashi Ouchi


Born in Japan in 1965, Hisashi Ouchi started working in the nuclear energy sector during what was an important time for his country. During a time when Japan had minimal natural resources and a heavy dependence on imported energy, the country had turned to nuclear energy production, building the first commercial nuclear power plant in the country just four years before he was born.


The power plant was constructed in Tokaimura, an ideal location due to the amount of abundant land which led to a whole array of nuclear reactors, research institutes, disposal, and fuel enrichment facilities. The huge growth of the nuclear power plant quickly led to one-third of the population of the city relying on the nuclear industry rapidly growing in the Ibaraki Prefecture northeast of Tokyo.


Hisashi Ouchi became the most radioactive man in history
Hisashi Ouchi became the most radioactive man in history

On March 11, 1997, terrified locals watched in horror as an explosion erupted at the Tokaimura nuclear power plant. Dozens of people were exposed to radiation before a government coverup quickly swept in to attempt to hide negligence. Two short years later, the gravity of that event would be dwarfed.


The nuclear plant converted uranium hexafluoride into enriched uranium for nuclear energy purposes. Under normal circumstances, this was done in a slow, methodical manner, with a multi-step process that involved mixing several elements in a carefully-timed sequence.



In 1999, officials had started to experiment, hoping to be able to skip some of those original steps to speed up the process. This had caused them to miss a deadline for generating fuel that was due on September 28.


At around 10 a.m. on September 30, Hisashi Ouchi, along with his 29-year-old colleague Masato Shinohara, and their 54-year-old supervisor Yutaka Yokokawa attempted a shortcut.


All of them were clueless about what they were actually doing and the risks that it involved. Instead of using automatic pumps to mix 5.3 pounds of enriched uranium with nitric acid in a specifically designed vessel, they used their hands to pour 35 pounds of it into steel buckets. At 10:35 a.m. that uranium reached critical mass.


Suddenly, the room exploded with a bright blue flash which confirmed that a nuclear chain reaction had occurred and was releasing lethal emissions of radiation.


Hisashi Ouchi Became The Most Radioactive Man In History


Hisashi Ouchi and his colleagues were rushed to the National Institute of Radiological Sciences in Chiba while the nuclear power plant was evacuated. All of them had been directly exposed to the radiation, due to their proximity to the fuel, they all suffered different degrees of radiation.


Being exposed to more than seven sieverts of radiation is considered fatal. Yutaka Yokokawa, the supervisor, was only exposed to three sieverts and was the only one in the group who would survive. Masato Shinohara was exposed to 10 sieverts, while Hisashi Ouchi, who was stood directly over the steel bucket, was exposed to 17 sieverts.


The level of exposure that Hisashi Ouchi experienced was the most radiation that any human had ever suffered. Immediately he was in agonizing pain and struggling to breathe. When he arrived at the hospital, he had already been violently vomiting and had fallen unconscious, radiation burns covered his whole body and his eyes were leaking blood.


His biggest problem was the lack of white blood cells which resulted in virtually no immune system. Doctors assessed the damage to his internal organs and placed him in a special ward to prevent infection. Three days later, Ouchi was transferred to the University of Tokyo Hospital where they would test revolutionary stem cell procedures.


During his first week in intensive care, Hisashi Ouchi went through numerous skin grafts and blood transfusions. Hisamura Hirai, a cell transplant specialist suggested a revolutionary approach that had never been tested on radiation victims before: stem cell transplants. These would rapidly restore Ouchi's ability to generate new blood.

This approach would be a lot faster than bone marrow transplants, Hisashi Ouchi's sister agreed to donate her own stem cells to help her brother. This method initially, appeared to work, before Ouchi returned to his state of near-death.


Photographs taken by the doctors showed the complete destruction of Hisashi Ouchi's chromosomes. The huge amount of radiation that was pumping through his blood had completely eradicated the introduced cells. Further images of Ouchi show that the skin grafts could not hold because his DNA could not rebuild itself.


At one point Hisashi Ouchi was quoted crying out, "I can't take it anymore, I am not a guinea pig."


His family was insistent on allowing the doctors to continue their experimental treatments, even after the skin of Hisashi Ouchi began to melt away from his body.

Hiashi Ouchi's skin melted away from his body
Hisashi Ouchi's skin melted away from his body due to the level of radiation

On the 59th day of his hospital stay, Hisashi Ouchi suffered a heart attack. However, his family agreed that in case of death he should be resuscitated, so the doctors revived him. He eventually had three heart attacks all within one hour.


Hisashi Ouchi's fate had long been sealed, but his pain and suffering had been dragged on longer than it needed to be, with his brain damage decreasing every time he died, and his DNA obliterated it was impossible for him to make a recovery. On December 21, 1999, Ouchi suffered another cardiac arrest due to multi-organ failure, this time it was fatal, finally releasing him from the pain and suffering he had to endure.


The Aftermath Of The Tokaimura Disaster


310,000 villagers within a six-mile radius of the nuclear facility were ordered to remain indoors for 24 hours. Over the following 10 days, 10,000 people were examined for radiation, with more than 600 individuals suffering low levels.


No one suffered anywhere near as much as Hisashi Ouchi and his work colleague, Masato Shinohara.



Shinohara spent seven months fighting for his life. He had also received blood stem cell transfusions. In his case, doctors took them from the umbilical cord of a newborn baby. Unfortunately, this approach, nor blood transfusions, cancer treatments, or skin grafts worked, and he died of lung and liver failure on April 27, 2000.


The supervisor of the two dead workers, Yokokawa was released after three months of intense treatment. He had suffered minor radiation sickness but managed to pull through. In October 2000, Yokokawa had to face criminal charges of negligence. JCO, however, would pay out $121 million to settle 6,875 compensation claims from affected locals.


The nuclear power plant in Tokai continued to operate under a different company for more than a decade until it shut down during the 2011 Tōhoku earthquake and tsunami. It has not operated since.


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