(R) for the first 96 hours after the test. . The Bravo crater is on the North West end of the atoll.
The device's firing crew were located on Enyu island, variously spelt as Eneu island as depicted in this map. The
Daigo Fukuryū Maru (
Lucky Dragon No. 5) encountered the
fallout from the U.S. Castle Bravo nuclear test at Bikini Atoll, near the
Marshall Islands, on March 1, 1954. When the test was held, the
Daigo Fukuryū Maru was catching fish outside the danger zone that the U.S. government had declared in advance. However, the test was more than twice as powerful as predicted, and changes in weather patterns blew nuclear fallout, in the form of a fine ash, outside the danger zone. On that day, the sky in the west lit up like a sunset. The
Daigo Fukuryū Maru was not damaged by the shock wave from the blast. However, several hours later white, radioactive dust made up of radioactive particles of coral and sand fell upon the ship. The fishermen attempted to escape from the area, but they took almost six hours to retrieve fishing gear from the sea and process fish (mainly shark and tuna) caught on the lines, exposing themselves to the radioactive fallout. The fishermen scooped the highly radioactive dust into bags with their bare hands. One fisherman,
Oishi Matashichi, reported that he "took a lick" of the dust that fell on his ship, likening the falling material to 粉雪 ("powdered snow") and describing it as gritty but with no taste. The dust stuck to their bodies and the ship, entering their nasal passages and ears, irritating their eyes and collecting inside their underwear. Radiation sickness symptoms appeared later that day. Due to this, the fishermen called the white ash
shi no hai (死の灰,
death ash). The ash that fell upon the ship carried
strontium-90,
cesium-137, and
uranium-237.
Events between March 2 and 14 During their return, the crew began showing symptoms of radiation poisoning as early as the evening after exposure. They experienced pain, headaches, nausea, dizziness, and diarrhea. Their eyes began to turn red and developed an itchy mucus. One crewman decided to keep some of the ash in order to have it analysed on their arrival home, but it was kept in a pouch hung from one of the bunks and was therefore in close proximity to the sleeping men for the duration of their return. Later analysis of the sample by, among others, Tokyo University determined that the ash was caused by a hydrogen bomb. The announcement of this news came as a large surprise to the Americans as they had persistently kept their nuclear experimentation secret. By the third day, the men began to develop small blisters on their bodies where they had been touched by the radioactive ash. Their faces also began to turn dark. A week into their return journey, their hair began to fall out. On March 11, the ship encountered rough seas causing them to dock late on March 14. This late arrival fortunately caused the contaminated fish to stay within the ship until the next morning. Thus, they were able to throw away much of the tuna once they discovered the radiation.
Events after return to Yaizu port , assessing the radioactivity of a bedridden crew member by using a
geiger counter on 31 March 1954, focusing on the person's hair, which would have collected dusty fallout. with a geiger counter before sale at a
fishmonger's on 31 March 1954 After their arrival, the men went to the Yaizu Public Hospital, where the surgeon, Oi Toshiaki, applied a zinc ointment to their faces and sent them home. On March 15, 1954, engineer Yamamoto, deckhand Masuda, and 5 others who were said to make up the "elderly" crew members were sent to the Tokyo University Hospital for treatment. There, they tested Masuda's bone marrow and found his white blood cell count at half the normal level. Japanese biophysicist Nishiwaki Yasushi immediately traveled from
Osaka to Yaizu to examine the crew and their boat. He quickly concluded that they had been exposed to radioactive fallout and wrote a letter to the chief of the US
Atomic Energy Commission (AEC) asking for more information on how to treat the crew. The crew members, suffering from nausea, headaches, burns, pain in the eyes, bleeding from the gums, and other symptoms, were diagnosed with
acute radiation syndrome. The US did not respond to Nishiwaki's letter or letters from other Japanese scientists requesting information and help. However, the United States did dispatch two medical scientists to Japan to study the effects of fallout on the ship's crew and to assist their doctors. The remaining crew members were quarantined in Yaizu North Hospital with all of their clothes and belongings buried on the property. High levels of radiation were found in the men's hair and nails, and so the hospital was forced to cut off the rest of their hair. There is a hint of criticism from one of the crewmembers, Oishi Matashichi, aimed at the then Japanese Foreign Minister
Katsuo Okazaki in his book, citing the fact that despite the lingering resentment towards the US over the atomic bombings of Hiroshima and Nagasaki in 1945, and the suspicion that US officials were only interested in research rather than attempting to cure anyone of their subsequent bombing-related ailments, Foreign Minister Okazaki is said to have spoken frequently to the crew about the need for the Americans to be present during treatment. Indeed, Oishi goes as far as to say "The Foreign Minister usually stood on the American side, and it appeared that he was the American Foreign Minister (rather than our own)." The men were all transferred to the Tokyo University Hospital. There, they would remain for 14 months or more in some cases. They were subjected to daily examinations and multiple blood samples. Bone marrow was also drawn from different areas in the men. Their red and white blood cells had dropped significantly, causing internal bleeding and bloody stools. They had constant high fevers, bled from their noses and gums, and had persistent diarrhea. Their sperm counts also fell to low numbers or, in some cases, to none. For their treatment, the men were prescribed bed rest and given large quantities of antibiotics and blood transfusions. Dr. Morita Hisao reported that the men had developed acute panmyelosis, a disease that attacked their bone marrow destroying its ability to generate blood. Around August 20,
Kuboyama Aikichi's condition deteriorated. By August 29, he fell into critical condition after developing meningitis. He became delirious and violent, having to be tied to a bed on the floor. Kuboyama soon fell into a coma and developed pneumonia. On September 23, he became the first member of the crew to die from complications of radiation sickness. The remaining 22 crew members were released from the hospital on May 20, 1955, after 14 months. They received yearly checkups to monitor the toll of long-term radiation sickness complications. ==Health history of the surviving crew==