Ghent sidered to be in a reasonably safe position since the personnel vere able to get into a well protected ares deep in the bunker, reading approximately 35 o/h. The cloud tracking (by WB-29, Wilson 2) during the morning of B Day indicated no contamination of consequence moving toward Eniwetok or Ujelang at ten thousand feet. The afternoon upwind mission for Wile son 2 was a 30 degree sector cut to 500 NK centered on true bearing of 70° from GZ. During the upwind portion of the cloud tracker's mission, readings were from 100 to 500 mr/bhr at ten thousand feet. During the morning ‘the B Day P2V sweep in front of the cloud encountered contemination early in bis mission. This P2V was replaced by another, which eompleted the search out to 600 NM. A report was received about 1500 on B Day that the AEC/HYOO instrue s™. 7. ment in the janis of the weather detachzent on Rongerik had gone off scale. These instrunents hed a full scale reading of 100 ar/hr. The off-seale report was not viewed with concern since task force ships were experiencing readings (while steaming south) of more than 100 =/ be (The BATROKO going as high as 1.0 r/br on the flight deck). Com sidering the distance (133 NM) and a cloud tracker at about 1945M, 1 March, reporting of zero contamination over Hongerik, it was generally believed that Rongerik and the task force ships were caught in e gene~ ral pattern of finely divided (95% less than 5 micron by cascade is -”- pactor) particles over a wide area moving ENE to BE. tachment was advised of this condition. The weather de- Nevertheless, the ABC/HY0O Ewajalein Flight ABLE was requested at midnight to be run the following mrning, Xwajalein Flight ABLE pattern covers all Marshall Islands north of Kwajalein, ani up to Taongi as the northern~-most turning point. Serial readings taken on the flight are extrapolated to the grouml. About 2000 the task force commander was briefed on the overall sitnation as was known at this time. This included the resulta of sone im itial damage and radsafe survey information taken about noon by helicop= ter, reports from the sampling aircraft (F-84, B-36 Featherweights end B-36 Control), the first twelve hour cloud tracking eission (Rilsca 2) and the first few reparts on the 5/12 to 5/24 hour cloud tracker (Filsoa 3). The upwind mission for Wilson 3 was a 30 degree sector out to 500 (~~~ KY centered on true bearing of 65 degrees from Rongerik, followed by & vectored mission to 17N 163E to base at Eniwetok. The task force com nenier was advised that fairly heavy contamination bad been encountered by Wilson 2 in the sector portion of kis flight and that one P2v aire craft had been contaminated in about the sane region. The task force commander was advised that the readings taken at ten thousand feet by the cloud trackers were thooght to be on the order of magnitute of that encountered by the task force ships. Since the only significant com