P- | 49 History: 1526-1972 Dese¢ription and FIGURE 1-47. STRUCTURE-TEST BRICK HOUSE, ENJEBI. . , instrumentation lines, as well as to provide access to the shot i ; island. Figure I-50 shows the island chain after Event Mike. The second test of Operation Ivy, Event King, was an air drop 2,000 feet north of Runit. The detonation took place at an altitude of 1,500 feet and i § d 4 OPERATION CASTLE: FEBRUARY-MAY 1954 : detonated. Weapons with greater energy releases were of the fusion type. In September 1952, the AEC removed Bikini Atoll from the provisional status in which it had been held since Operation Crossroads and made ita part of the Pacific Proving Ground. In the next test series, Operation Castle, five of six shots were carried out at Bikini. Only Event Nectar, a barge shot, was conducted at Enewetak. The shot location was Mike Crater, and the yield was 1.69 MT.83 One of the Bikini shots, Bravo, became well known because the fallout from this 1s MT detonation was carried to the east, rather than to the north as had been predicted, andfell on the atolls of Rongelap, Ailinginae, and Rongerik. Fallout was heavy enough to cause serious illness and at least one death among the crew of the Japanese fishing boat Fikuryu Maru, which had not received warning of the test and hadsailed into the danger zone. These events produced renewed interest in radiological health foe the yield was 500 KT.82 This was the largest fission weapon ever