Project 4.1
In 1994, a 1953 "Castle Bravo" program prospectus was found which included reference to Project 4.1 apparently written before the "Bravo" shot had occurred. The U.S. government responded that someone had gone back into the project list after the "Bravo" test to insert Project 4.1; thus, according to the U.S. government, the acts were not premeditated. All other U.S. documents point to Project 4.1 having been established after the "Bravo" test—most sources point to its having been organized on March 7, 1954. The final Project 4.1 report began in its preface with the statement that "Operation CASTLE did not include a biomedical program" (it mentions this in discussing the ad hoc nature by which the project personnel were assembled). All official and mainstream historical accounts of the "Bravo" test indicate that its high level of fallout was a result of a miscalculation in relation to its design and was not deliberate (see the Castle Bravo article for more information on the alleged accident).
Castle Bravo
Unanticipated fallout and the radiation emitted by it also affected many of the vessels and personnel involved in the test, in some cases forcing them into bunkers for several hours. In contrast to the crew of the "Lucky Dragon No. 5", who did not anticipate the hazard and therefore did not take shelter in the hold of their ship, or refrain from inhaling the fallout dust, the firing crew that triggered the explosion was able to safely shelter in their firing station when they noticed the wind was carrying the fallout in the unanticipated direction towards the island of Enyu on the Bikini Atoll where they were located, with the fire crew sheltering in place ("buttoning up") for several hours until outside radiation decayed to safer levels. "25 Roentgens per hour" was recorded above the bunker.