7 minutes before this article was posted, Tepco finally announced the reason why the Fukushima worker died (The official third dead person) at a press conference. He was in his 50s.
The person died of septic shock caused by retroperitoneal abscess.
The point is that he died of septic shock, which is the typical symptom of the immune system trouble.
It can be caused by HIV or reduction of WBC (white blood cells) because of chemotherapeutic measures or radiation exposure.
It had been concealed in the name of “privacy” but when they got the approval of the family, they finally announced it.