This happened in 1999.
Hisashi Ouchi, from Japan, worked in a manufacturing plant for nuclear fuel. That is to say, his plant did not use the fuel to generate electricity, but manufactured it for the power plants.
On the last day of September, 1999, Hisashi came to work as always. I want to say he went through the safety measures like always as well, but the plant had abysmal safety.
You see, the way you're supposed to mix the materials (intermediate-enriched uranium oxide) is that you have a machine do it for you, storing each material in a tall, thin tank because this material is volatile. It's a slow process that requires proper safety precautions and good timing: neither too slow nor too fast.
At the Japan Nuclear Fuel Conversion Company, this was done by hand. Over a wide tank. One man held a funnel over the tank while the other poured the material in.
Again, this makes nuclear fuel. I won't pretend to understand radioactivity but the various nuclear compounds such as uranium are not all equally dangerous or radioactive. They are also not all equally unstable and you don't necessarily need protection to work with uranium oxide.
That morning, eager to meet deadlines, Hisashi's boss told him to go mix a batch with another coworker. Neither of the two were trained to do this procedure. The boss showed them how to do the procedure, and then Hisashi offered to hold the funnel. Neither of the two knew how catastrophic this could be, because this was normally not their job.
Almost as soon as Hisashi's boss went back to his desk a bit further in the mixing room (why would you ever put a desk in a room containing radioactive material I do not know), the worker over the tank accidentally poured in eight times as much uranium in the tank.
Instantly, a flash of blue light blinded all three men in the room. They had just caused a criticality incident, an uncontrolled nuclear reaction.
Instantly, the boss yelled "Get out!" and, by some accounts, was the first out of the room. The plant was evacuated and so was the town surrounding the plant.
All three men were brought to the hospital, and for Hisashi, the foremost nuclear sickness expert in Japan was brought in instantly, because while he hadn't seen this exact scenario before, he knew it wasn't going to be good. You see, when you initially get exposed to such high doses of radiation, you feel fine at first, for a few hours to a few days -- if a bit hot and itchy. But the process is already happening, and the worst is yet to come.
The boss made a speedy recovery; he was far enough from the criticality event. It was Hisashi who received a dose of nuclear radiation over his entire body.
I won't relay Hisashi's ordeal that took place over the next 83 days, but suffice to say he died at the end of it. But I will say that I believe the doctors (and Hisashi) did everything they could to save him, because at times it seemed like there might have been a chance. I don't think they kept him alive to torture him or study his radiation sickness.
The coworker also died some time after Hisashi.
Capitalism killed this man. When you read the story in other publications, the writers are not keen to put the blame on their perfect system.
But when you read that he Japanese government's investigation concluded that the accident's main causes included inadequate regulatory oversight, lack of an appropriate safety culture, and inadequate worker training and qualification, you really can't come out of it thinking anything other than capitalism killed this man.
The company stopped their uranium enrichment activities in 2003 by the way, but continue to exist. In my opinion, such gross negligence should have pulled their credentials; this company should not be allowed to operate anything close to radioactive. But Japan will be Japan.