Daigo Fukuryū Maru
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" did not get 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 6 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, selenium-141, and uranium-237.