11 Of The Worst Deaths That Human Beings Have Ever Experienced

Published September 21, 2022
Updated March 12, 2025

Hisashi Ouchi: The Lab Technician Who Suffered The Worst Radiation Death In History

Hisashi Ouchi

Peak Interest/YouTubeHisashi Ouchi became the most radioactive man in history after a lab accident.

There’s a reason why workplace health and safety guidelines exist, and the chilling story of Hisashi Ouchi shows just how important they are — especially if you happen to work at a nuclear power plant.

On September 30, 1999, the 35-year-old Ouchi and two others were working at the Tokaimura Nuclear Power Plant in Tokaimura, Japan under a tight deadline put in place by the Japan Nuclear Fuel Conversion Company.

The plant converted uranium hexafluoride into enriched uranium for the purposes of nuclear energy. This usually involved a meticulous, carefully-timed, multi-step process. But Ouchi and his coworkers Masato Shinohara and Yutaka Yokokawa attempted to take a shortcut to meet their deadline.

Unfortunately, this led to a horrific nuclear accident involving a uranium solution. The plant underwent emergency evacuation as the three men were rushed to the National Institute of Radiological Sciences in Chiba. They had all been directly exposed to harmful radiation, but to different degrees.

Yokokawa, the sole survivor of the group, was exposed to three sieverts of radiation. Shinohara was exposed to 10 sieverts. And Ouchi was exposed to a whopping 17 sieverts — which was more than any human in history.

Tokaimura Nuclear Power Plant

Wikimedia CommonsThe nuclear plant where Hisashi Ouchi worked.

By the time Ouchi arrived at the hospital, his body was already covered in burns, and his eyes were leaking blood. But his agony had just begun.

Three days after the accident, Ouchi was transferred to the University of Tokyo Hospital. His lack of white blood cells and his nonexistent immune response prompted experts to try a number of procedures to save him.

At first, doctors tried countless skin grafts and blood transfusions. Then, they attempted stem cell transplants. Sadly, none of this seemed to be working. And according to the Daily Star, Ouchi soon cried out, “I can’t take it anymore! I am not a guinea pig!” just a week into his treatment.

But although he begged for death, his family insisted that doctors keep trying experimental treatments. Even when Ouchi’s skin began to melt from his body, his relatives ordered his doctors to do whatever it took to keep him alive. All in all, Ouchi was kept alive against his will for a harrowing 83 days.

At one point, he suffered three heart attacks in one hour. Following the guidelines from his family, the doctors resuscitated him again and again. Every time he died and came back, he suffered brain damage.

On December 21, 1999, Ouchi finally, mercifully died of his last heart attack after multi-organ failure. It was only then that his torture ceased.

author
Austin Harvey
author
A staff writer for All That's Interesting since 2022, Austin Harvey has also had work published with Discover Magazine, Giddy, and Lucid, covering topics including history, and sociology. He has published more than 1,000 pieces, largely covering modern history and archaeology. He is a co-host of the History Uncovered podcast as well as a co-host and founder of the Conspiracy Realists podcast. He holds a Bachelor's degree from Point Park University. He is based in Pittsburgh, Pennsylvania.
editor
Jaclyn Anglis
editor
Based in Brooklyn, New York, Jaclyn Anglis is the senior managing editor at All That's Interesting, where she has worked since 2019. She holds a Master's degree in journalism from the City University of New York and a dual Bachelor's degree in English writing and history from DePauw University. In a career that spans 11 years, she has also worked with the New York Daily News, Bustle, and Bauer Xcel Media. Her interests include American history, true crime, modern history, and science.
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Harvey, Austin. "11 Of The Worst Deaths That Human Beings Have Ever Experienced." AllThatsInteresting.com, September 21, 2022, https://allthatsinteresting.com/worst-deaths. Accessed July 15, 2025.