Hisashi Ouchi

Following a tragic incident at Japan’s Tokaimura nuclear power plant in 1999, Hisashi Ouchi endured severe radiation exposure that led to the loss of most of his skin and, eventually, tears of blood before his suffering came to an end.

Upon arrival at the University of Tokyo Hospital, doctors were astonished by Hisashi Ouchi’s condition after he experienced the highest recorded level of radiation exposure in human history.

The 35-year-old technician from the nuclear power plant had virtually no white blood cells left, leaving him without any immune system. It wasn’t long before he began to shed tears of blood as his skin began to dissolve.

The nuclear disaster unfolded on the morning of September 30, 1999, at Tokaimura’s nuclear power plant in Japan.

Despite glaring safety lapses and a rush to meet deadlines, Japan Nuclear Fuel Conversion Co. (JCO) instructed Hisashi Ouchi and two colleagues to mix a new batch of fuel rods manually.

Lacking proper training, the three men poured seven times the required uranium into an inappropriate tank.

Ouchi stood directly over the vessel when Gamma rays flooded the room, prompting evacuations of the plant and nearby villages. Little did Ouchi know his harrowing journey had just begun.

Confined to a specialized radiation ward to minimize infection risks, Ouchi endured fluid leaks and tearful pleas for his mother.

Despite numerous cardiac arrests, he was resuscitated against his family’s wishes. Ultimately, after 83 agonizing days, his suffering ended with a final cardiac arrest.

Hisashi Ouchi’s Role at the Tokaimura Nuclear Power Plant

Born in Japan in 1965, Hisashi Ouchi started his career in the nuclear energy sector during a critical period for his country.

Facing limited natural resources and costly reliance on imported energy, Japan turned to nuclear power generation and established its inaugural commercial nuclear power plant just four years before Ouchi’s birth.

The Tokaimura power plant was strategically located in a spacious area, establishing a comprehensive campus with nuclear reactors, research institutions, and fuel enrichment and disposal facilities.

This rapid development transformed Ibaraki Prefecture, northeast of Tokyo, where eventually, one-third of the city’s population relied on the burgeoning nuclear industry.

In a harrowing incident on March 11, 1997, Tokaimura was shaken by an explosion at a power reactor, exposing dozens of individuals to radiation.

A subsequent government cover-up attempted to conceal negligence, though the severity of the incident would be eclipsed just two years later.

The plant’s primary function was converting uranium hexafluoride into enriched uranium for nuclear energy applications.

This involved a meticulous, multi-step process requiring precisely mixing various elements in a carefully timed sequence.

In 1999, officials began experimenting with shortcuts to expedite the process, ultimately missing a critical deadline of September 28 for fuel generation.

Consequently, around 10 a.m. on September 30, Hisashi Ouchi, 29-year-old Masato Shinohara, and their 54-year-old supervisor Yutaka Yokokawa, attempted a risky shortcut.

Unfamiliar with the procedure, they bypassed automatic pumps and manually poured 35 pounds of enriched uranium into steel buckets intended to be mixed with nitric acid in a designated vessel. By 10:35 a.m., the uranium had reached critical mass.

A sudden blue flash signaled a nuclear chain reaction, releasing deadly radiation emissions into the room.

Hisashi Ouchi: Enduring the Most Severe Radiation Exposure in History

Following the critical nuclear accident, Hisashi Ouchi and his colleagues were swiftly evacuated from the plant and transported to the National Institute of Radiological Sciences in Chiba.

Each had suffered direct radiation exposure, varying in severity depending on their proximity to the uranium fuel.

Radiation doses above seven sieverts are usually deadly. Yutaka Yokokawa, the supervisor, was exposed to a much lower dose of three sieverts and managed to survive. But for the others, it was far worse.

Masato Shinohara received 10 sieverts, while Hisashi Ouchi, who was, unfortunately, standing right above the bucket during the accident, absorbed a massive 17 sieverts of radiation.

Hisashi Ouchi endured the highest recorded radiation exposure ever suffered by a human. Immediately after the accident, he was in excruciating pain, struggling to breathe.

Upon arrival at the hospital, he had already experienced severe vomiting and lost consciousness. Ouchi’s entire body was covered in radiation burns, and he suffered from hemorrhaging eyes.

Most critical was his severe depletion of white blood cells and the complete absence of immune function. To prevent infections, doctors placed him in a specialized ward and carefully assessed the damage to his internal organs.

Three days later, he was transferred to the University of Tokyo Hospital, where innovative stem cell treatments were considered.

During his initial week in intensive care, Ouchi underwent numerous skin grafts and blood transfusions.

Dr. Hisamura Hirai, a specialist in cell transplants, proposed a groundbreaking approach never attempted on radiation victims: stem cell transplants. These aimed to restore Ouchi’s ability to produce new blood cells rapidly.

Despite initial signs of success, the method proved fleeting as the overwhelming radiation in Ouchi’s bloodstream swiftly destroyed the transplanted cells.

Photographs of Ouchi’s chromosomes revealed severe damage, highlighting the inability of his DNA to regenerate. 

Skin grafts failed to hold due to this profound cellular devastation.

“I can’t take it anymore,” cried Ouchi. “I am not a guinea pig.”

Against his family’s wishes, doctors persisted with experimental treatments even as Hisashi Ouchi’s skin began to disintegrate.

Hisashi Ouchi

On his 59th day in the hospital, he suffered a heart attack, prompting his family to authorize resuscitation. Over an hour, he endured three more heart attacks.

With his DNA severely damaged and suffering increasing brain damage with each episode of cardiac arrest, Ouchi’s fate was inevitable.

Finally, on December 21, 1999, mercifully, he succumbed to multi-organ failure, bringing an end to his excruciating suffering.

Consequences Following the Tokaimura Disaster and Ouchi’s Passing

Following the Tokaimura nuclear accident, immediate measures were taken as 310,000 villagers within six miles of the Tokai facility were instructed to remain indoors for 24 hours.

In the subsequent 10 days, 10,000 individuals underwent radiation screenings, revealing that over 600 had experienced low-level radiation exposure.

However, the most severe consequences were borne by Hisashi Ouchi and his colleague, Masato Shinohara.

Shinohara fought for his life for seven months, undergoing treatments including blood stem cell transfusions sourced from a newborn’s umbilical cord.

Despite efforts such as skin grafts, blood transfusions, and cancer therapies, none were successful. He succumbed to lung and liver failure on April 27, 2000.

In contrast, the supervisor of the two deceased workers, Yokokawa, was discharged after three months of medical care. He experienced mild radiation sickness but survived. However, he faced charges of negligence in October 2000. 

Meanwhile, JCO settled 6,875 compensation claims from affected locals, amounting to $121 million.

The Tokai nuclear power plant remained operational under new management for over ten years until it automatically shut down during the 2011 Tōhoku earthquake and tsunami. Since then, the plant has remained inactive.

Richard is an experienced tech journalist and blogger who is passionate about new and emerging technologies. He provides insightful and engaging content for Connection Cafe and is committed to staying up-to-date on the latest trends and developments.