All 23 crew members were exposed to radioactive fallout from a hydrogen bomb test conducted by the United States on March 1, 1954.
A crew member in charge of operating the ship’s ham radio died just six months after the incident.
Oishi was hospitalized for a year and two months, suffering from hair loss and leukopenia.
When Oishi was finally released from the hospital, he faced prejudice and discrimination.
People spread baseless information about him, saying things such as, “I don’t want to catch his radiation.”
People avoided him. And the fact that he received compensation from the U.S. government evoked envy.
The circumstances drove Oishi to leave his hometown and move to Tokyo, where he kept his past a secret.
That changed in 1983, when Oishi was asked by students at a junior high school in Machida, western Tokyo, to talk about his experience.
After that, Oishi became actively involved in the anti-nuclear movement.
He traveled to the Marshall Islands and the United States to share his story, which included the death of his child at birth.
All told, he spoke on more than 700 occasions.
“The Bikini incident will disappear unless I keep talking about it,” he often said.
One of the activities he was most passionately involved in was a project to build a stone monument called “tuna mound” in the capital’s Tsukiji district.
Days after the hydrogen bomb test, tuna caught by the crew of the Daigo Fukuryu Maru were unloaded at the Tsukiji fish market and radiation was detected in the fish. That was just the beginning.
In 1954, radiation was detected from fish caught by about a total of 1,000 fishing vessels. All the contaminated fish had to be thrown away.
Oishi urged the metropolitan government to build the monument in the hopes it would help pass the story to future generations.
He had suffered from liver cancer and a brain hemorrhage. But he did not lose his fighting spirit.
Oishi reportedly said, just few weeks before his death, “I still have things that I want to say and stories that I want to tell.”