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
A Japanese fishing boat, "Daigo Fukuryū Maru" (Lucky Dragon No.5), came in direct contact with the fallout, which caused many of the crew to grow ill; one died of a secondary infection. This resulted in an international incident and reignited Japanese concerns about radiation, especially as Japanese citizens were once more adversely affected by US nuclear weapons. The official US position had been that the growth in the strength of atomic bombs was not accompanied by an equivalent growth in radioactivity released. Japanese scientists who had collected data from the fishing vessel disagreed with this.