Bikini lagoon contamination of consequence was confined to lagoon areas containing suspended sediment. For the first few days this area was confined to the western quarter of the lagoon, This radioactive sediment washed over the western reef, out through the southwest passage, or settled to the bottom of the lagoon in a period of three days. tivity was detected in swipes about the living areas of the Task Group. No al ha (0) results A partial Rad-Safe survey was conducted able 4,2), Results of this survey indicated no extensive recon th incomplete atol! tion of the atoll MMARY IN ROENTGENS PER HOUR now Cal Me on ne Ae oS Ree + Island Enyu Bikini* Aomoen* Romurtida*® 0,03 0.20 0.80 1.6 Vorikku® 0.6-1.4 Yurochi® Namu* Bokobyasdaa*® Ouruksen Arrifkan 0.8-1.0 2000 1000 0,04 0.02 Entirikiu Alrukiljt Eninman 0.005 0.02 0.012 Crater Ships “0,03 0.12 0.80 1.7 _ 0,06 0.14 0.60 0.75 0.03 0.12 0.22 li 1.4 0.85 1.2 1.3 50.07 0.103 0.40% 1,0 100 55 0,16f 0,32f 1.3 0.6 1.2 0,04 0,02 0,005 0.01 0.012 0.05 0.08 0.08 0,01 0.01 11008 0,020.04 *Contamination by Runt I shot, 1200-f altitude, tRadiation shine from water in southwest passage. fAt 300 ft. except within the Bokobyaadaza-Namu chain. An unforeseen fall-out of radioactive material leas than 5 » in size did occur on the nigh This fall-out covered the atoll and raised radiation levels by approximately 100 . pecause of the late period of fall-out, this radiation level would have corresponded to 3.5 r/hr fall-out at H+2 hr. Because of small particle size this fall-out was much more difficult to decontaminate than the macroscopic particles’ Recta Secondary fall-out leveled off between 0700—0800M, ships were Ainsworth, 8 mr/hr; Estes, 12 mr/hbr; and Bairoxo, were 20 to 45 mr/hr. Residual topside levels on mr/hr, Maximum levels - Lagoon contamination covered the western quarter of the lagoon with levels comparable to [EIS|L25000 flushing through the southwest passage materially increased background-radiation levels in the vicinity of Ourukaen, Bokoaetokutoku, ‘und Bokororyuru. mca| partial Rad-Safe survey was condeTA in- complete atoll results (Table 4.3). Results of this survey did indicate that Bokobyaadaa, Namu, Eniirikku, Bikint, and the Yurochi-Aomoen chain were materially contaminated. Reentry and recovery were accomplished to a large degree on shot day. No secondary fall-out was detected as results of this shot. Lagoon contamination was restricted to a V-shaped pattern with apex at Eninman andtips covering the Bokobyaadaa-Aomoen area. A reading of 100 mr/hr was obtained over the Enin- BEST AVAILABLE COPY