Castle Bravo
The decision to carry out the Bravo test under the prevailing winds was made by Dr. Alvin C. Graves, the Scientific Director of Operation Castle. Graves had total authority over detonating the weapon, above that of the military commander of Operation Castle. Graves appears in the widely available film of the earlier 1952 test "Ivy Mike", which examines the last-minute fallout decisions. The narrator, the western actor Reed Hadley, is filmed aboard the control ship in that film, showing the final conference. Hadley points out that 20,000 people live in the potential area of the fallout. He asks the control panel scientist if the test can be aborted and is told "yes", but it would ruin all their preparations in setting up timed measuring instruments. In Mike, the fallout correctly landed north of the inhabited area but, in the 1954 Bravo test, there was a large amount of wind shear, and the wind that was blowing north the day before the test steadily veered towards the east.
Radiophobia
March 1, 1954, the operation Castle Bravo testing of a then, first of its kind, experimental thermonuclear "Shrimp" device, overshot its predicted yield of 4–6 megatons and instead produced 15 megatons; this resulted in an unanticipated amount of "Bikini snow" or visible particles of nuclear fallout being produced, fallout which caught the Japanese fishing boat the Daigo Fukuryū Maru or "Lucky Dragon" in its plume, even though it was fishing outside the initially predicted ~5 megaton fallout area which had been cordoned off for the Castle Bravo test. Approximately 2 weeks after the test and fallout exposure, the 23-member fishing crew began to fall ill, with acute radiation sickness, largely brought on by beta burns that were caused by direct contact between the "Bikini snow" fallout and their skin, through their practice of scooping the "Bikini snow" into bags with their bare hands. One member of the crew, Kuboyama Aikichi the boat's chief radioman, died 7 months later, on September 23, 1954. It was later estimated that about a hundred fishing boats were contaminated to some degree by fallout from the test. Inhabitants of the Marshall Islands were also exposed to fallout, and a number of islands had to be evacuated.