The Deaths of Hisashi Ouchi and Masato Shinohara (1999 Tokaimura Nuclear Accident)

The 1999 Tokaimura accident occurred in a small fuel preparation plant operated by JCO (formerly Japan Nuclear Fuel Conversion Co.) in Tokai, Ibaraki Prefecture, Japan, and claimed the lives of two technicians: 35-year-old Hisashi Ouchi (left) and 40-year-old Masato Shinohara (right):

On September 30th, 1999, Shinohara was pouring buckets of uranyl nitrate into a nuclear fuel tank, while Ouchi held a funnel:

When Shinohara poured a seventh bucket, a flash of blue light (Cherenkov radiation) was seen, accompanied by a loud smacking noise. Both men became nauseous, and passed out. A third man, supervisor Yutaka Yokogawa, was sitting at a desk several meters away, and phoned for help. Yokogawa recovered in the hospital, but was later one of six men arrested for negligence at the Tokaimura facility. It’s believed the JCO (Japanese Atomic Fuel Conversion Co.), which went out of business in 2003, had cut corners on safety and training. The tank Ouchi and Shinohara were working with had no buffer which could have prevented such a criticality from occurring.

The estimated radiation doses of the 3 men are: Ouchi 16-25 Grays (Gy), Shinohara 6-12 Gy, and Yokogawa 1-4.5 Gy. It’s important to understand that these numbers are whole-body averages. In Ouchi’s case, he absorbed radiation disproportionately into his front right side, and particularly his right forearm:

When Ouchi arrived at the hospital, he was still in the “latent phase” of acute radiation syndrome (ARS), where the patient is relatively stable before deteriorating. He looked tan, and complained mainly of pain in his right arm. This early hospital photo also shows Ouchi as having an enlarged parotid gland in his cheek. Salivary glands are highly susceptible to radiation, and the mouth eventually dries out to the point where the victim is unable to talk or eat food.

On the fourth or fifth day, doctors’ worst fears were confirmed when a biopsy of Ouchi’s bone marrow showed extensive destruction of the chromosomes:

Ouchi was going to have a hard time regenerating cells, and the first symptoms would appear in his skin, blood, and gastrointestinal mucus membranes, as those cells undergo the most rapid rate of division. Ouchi had to be wrapped in a special product called Trex Gauze, since ordinary gauze, as well as towels and medical tape, would rip dead skin cells off his body.

On day 11, Ouchi lost his composure, proclaiming “I am not a guinea pig!” The lead physician who treated Ouchi and Shinohara, Dr. Kazuhiko Maekawa, admitted to the media in October that Ouchi’s dose of radiation was lethal. However, under Japanese law, for Ouchi to be euthanized, he would need to give consent, and be near-death. Some of Ouchi’s last written messages, after he was hooked up to a ventilator and lost the ability to speak, expressed desire to go home. Whether Maekawa kept Ouchi alive as a “guinea pig” or not, doctors were legally obligated to treat Ouchi until nothing more could be done.

Despite being given 200 mg of Fentanyl per hour, in conjunction with sedatives, doctors and nurses discerned pain from Ouchi’s facial expressions. He was given a novel type of stem cell transplant from his sister, which allowed for a temporary recovery of bone marrow and other tissues. In the end, the sister’s transplanted cells developed chromosome damage. Doctors believed this was either a result of the neutrons which struck Ouchi's body turning certain nutrients (i.e. sodium) radioactive, or Ouchi's own cells mutating to produce radioactive oxygen. The sister also provided a swath of skin from her thigh to use for cultured skin grafts. The grafts loosened, and did not adhere well, as Ouchi was losing up to 20 L of fluid per day through his skin.

On day 59, Ouchi’s heart stopped beating for 50 minutes. The strain on his heart had been comparable to a person running a marathon. He was resuscitated, and given drugs to ease the burden on his heart, but was now braindead. On day 63, Ouchi developed a rare syndrome called hemophagocytosis, which is normally associated with the Epstein-Barr virus. The lymphocytes (a type of white blood cell) made from the sister’s stem cells were recognizing Ouchi’s own cells as foreign, and attacking them. My guess is that this was due to the extreme breakdown of Ouchi’s DNA, to the point where his cells would appear foreign, or non-human, to the immune system.

On day 83, December 21st, late at night, Ouchi experienced another cardiac arrest, and the decision was made between doctors and family to not resuscitate. Remarkable organ changes were seen at autopsy. Ouchi’s intestines, which had produced up to 3 L of bloody or watery, green diarrhea throughout his ordeal, had lost their villi, and resembled a “writhing serpent” filled with blood.

Muscle cells undergo a slow rate of division (10-15 years), and are therefore less susceptible to radiation damage; the cells actually have time to repair the chromosomes, provided they’re not too damaged. But Ouchi’s dose of radiation was so extreme, his muscles lost their fiber, and detached from the bones. The only normal-looking organ in Ouchi’s body was his heart, which doctors interpreted as his will to live.

Shinohara's prognosis was better than Ouchi's, but still grim, as only one man from the Chernobyl disaster, out of twenty-two, survived an effective dose of radiation greater than 6 Gy. Because a suitable hematopoietic stem cell donor could not be found for Shinohara, he was given an infusion of stem cells from a fetal umbilical cord. He was still conscious in January, and taken to the hospital gardens in his wheelchair for New Year’s Day. In February, he contracted pneumonia, and on April 27th, day 211 of irradiation, he died. His kidneys, liver, pancreas, bone marrow, and muscles had all deteriorated, and he had widespread thrombotic microangiopathy in his small intestine. Doctors got about 90% of the skin grafts to adhere to Shinohara, but for unclear reasons, the engrafted skin became hard and brittle. A crunching noise was heard when his skin was cut into at autopsy.

The pronunciation of Ouchi's name is not quite like the English "ouch" it is more like "oh-uchi." These two horrific photos, which appear in numerous blog articles about Tokaimura, are NOT of Ouchi:

The bottom photo might be of Shinohara (but it might also be of a Chernobyl person) as the white strips mirror a cultured skin graft product called "Bio-Skin," which was used in the Tokaimura case.

The skinless man on the bed has also had his right leg amputated below the knee. Ouchi never underwent amputation, as doctors considered it too dangerous.

Source/more info: https://web.archive.org/web/20190615235906/https://answeringthemysteries.blogspot.com/2019/04/the-tokaimura-nuclear-accident-and-who.html