Castle Bravo
Castle Bravo was the first in a series of high-yield thermonuclear weapon design tests conducted by the United States at Bikini Atoll, Marshall Islands, as part of "Operation Castle". Detonated on March 1, 1954, the device was the most powerful nuclear device detonated by the United States and its first lithium deuteride fueled thermonuclear weapon. Castle Bravo's yield was 15 megatons of TNT, 2.5 times the predicted 6.0 megatons, due to unforeseen additional reactions involving Li, which led to the unexpected radioactive contamination of areas to the east of Bikini Atoll.
Daigo Fukuryū Maru
The crew suffered acute radiation syndrome (ARS) for a number of weeks after the Bravo test in March. During their ARS treatment, the crew were inadvertently infected with hepatitis C through blood transfusions. All recovered except for Aikichi Kuboyama, the boat's chief radioman, who died on September 23, 1954, from an underlying liver cirrhosis compounded by the secondary hepatitis C infection. Kuboyama is considered the first victim of the hydrogen bomb and of test shot Castle Bravo.