= UNCLASSIFIED throughout the day, and studies of beta ccvnt made in the laboratory, a cascade impactor was operated at the same time, Early in the afternoon fall-out appeared to have ceased but it caused considerable trouble for the deck monitors in their examination of equipment and clothing of parties returning from the test areas, The water samples from Kwajalein did not reveal any harmful contamination, No contamina~ tion was detected in the showers of rain that fell through the day. Fall-out was also detected on other ships of the Task Force, but toa lesser extent than on the BAIROKO, Negligible contamination was found in the evaporators which were being checked daily. YOKE Plus Three Day to ZEBRA Test The contamination of the lagoon waters had reached an insignificant figure by YOKE-plus 3 day, and further survey of the lagoon anchorage, other than an occasional spot check, was discontinued. The islands of Runit, Parry and Eniwetok were cleared for swimming and recreation parties.. The island immediately north of the test island was heavily contaminated from fall-out, and also received considerable radiation from the . crater, Stakes had been planted on this island prior to the test to assist in the survey, but none of them could be found after the blast. The extensive palm grove on the island had been completely destroyed. Monitor guards were established on YOKE-plus 4, and maintained , continuously until the island was closed just prior to ZEBRA test. Their presence considerably facilitated the work of the engineers in clearing evidence of blast effects from the island, Samples of wea’ -> obtained from Kwajalein, and other neighboring island groups, where fall-out occurred or where there had been a possibility of fall-out, were checked and found safe for human consumption, | The island of YOKE test was closed and declared a restricted area on YOKE-plus 11, Reconnaisance on the island of ZEBRA test, and the survey of lagoon currents off this island had already begun, ZEBRA Test A large area of fall-out was observedfrom the airextending out into the lagoon on an azimuth of 280° fram the zero point, This area was con firmed by boat patrol and its course plotted until it was assured that it was not a source of danger to the ships of the task force, Radsafe Party No. 4 ran into considerable difficulty on their mission, because snagging of the land cable made it impossible te wind the samples in to a safe area where they could be conveniently handled, The importance of obtaining these samples made it necessary to pick them up by jeep, which exposed the party to considerably greater radioacticity than had been met on ~ Bo _ 9001924 er _ UNCLASSIFIED