Gaerne sidered to be in a reasonably safe position since the perscanel vere able to get into a well protected ares deep in the bunker, reading arproxizately 35 ar/hr. The cload tracking (by WB-29, Wilson 2) during the morning of B Day indicated no contamination of consequence moving toward Exiwetok or Ujelang at ten thousand feet. The afternoon upwind aission far File son 2 was a 30 degree sector ait to 500 KK centered on true bearing of 70° from GZ. During the upwind portion of the clout trackers aissioa, readings were from 100 to 500 ar/br at ten thousand feet. During the morning the B Day P2V sweep in front of the cloud ensountere! contamiar etion early in bis miesion. This P2v was replaced by ancthe, which completed the search out to 600 FM, 4 repart was received about 1500 on B Day that the AEC/HYOO instrve YON. ment in the banis of the weather detachnent on Rongerix had gone off scale. These instruments had a full scale reaiing of 100 ar/kr. The off-scale report was not viewed with concern since task force ships were experiencing readings (while steaming south) of sore than 100 ar/ be (The BATROKO going as high as 1.0 r/hr on the flight deck). Com sidering the distance (133 NM) and a cloud tracker at ebout 195M, 1 March, reporting of zero contamination over Rongerik, it was generally dbeliewed that Rongerik and the task force ships were caught in a gene~ ral pattern of finely divided (95% less than 5 aicron by cascede is pacter) particles over « wide area moving EXE to EB. The weather de- tachment was advised of this condition. Nevertheless, the AmC/ETOO Ewajalein Flight ABLE was requested at midnight to be run the fallowing morning, Kwajalein Flight aBLE pattern covers all Marahell Islanis north of Kwajalein, and up to Taongi as the northern-post turning point. Aerial readings taken on the flight are extrapolated to the groan. About 2000 the task force comander was briefed on the overall sitnation es was known at this time. This included the results of some iz itial damage and radsafe survey inforsstion taken about noon by belicop- ter, reports from the sampling aircraft (P-8,, B-36 Peatherweighte and B-36 Coxtrol), the first twelve hour cloud tracking eission (Wilson 2) and the first few reports on the B12 to 5/24 hour cloud tracker (Filsos 3). Tiupwind mission for Wilson 3 was a 30 degree sector out to 500 KY cemfered on true bearing af 65 degrees fros Rongevik, followed by & m7 vectored mission to 17N 163E to base st Eniwetck. The task force com nesier was advised that fairly heavy contazination had been encountered by Filson 2 in the sector portion of bis flight and that one P2¥ aire ereft bad been contaminated in about the sane region. The task foree commander was advised that the readings taken at ten thousand fest by the cloud trackers were thought to be on the order of magnitude of tint encountered by the task force ships. Sinse the caly siguificant com