Widespread radioactive fallout itself was not recognized as a threat among the public at large before 1954 , until the widely publicized story of the 15-megaton surface burst of the experimental test shot Castle Bravo on the Marshall Islands . The explosive yield of the Castle Bravo device '' the Shrimp '' was unexpectedly high , and therefore correspondingly higher amounts of local fallout were produced . When this arrived at their location carried by the wind , this caused the 23 crew members on a Japanese fishing boat known as the Lucky Dragon to come down with acute radiation sickness with varying degrees of seriousness and due to complications in the treatment of the ship 's radio operator months after the exposure , resulted in his death
Castle Bravo
Castle Bravo
Duck and cover