UNCLASSIFIED , throughout the day, and studies of beta count 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 fran Kwajalein did not reveal any haraful contamination. Mo contamime- ~ tion was detected in the showers of rain that fell through the day, Fall-out was also detectsd on other ships of the Task Force, but toa lesser extent than on the BAIROKO, Neglisible contamination was found in the evaporators which were being checked daily. YOKE Flus Three Day to CEBRA Test The contamination of the lasoon waters had reiched 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 con- taninated from fall-out, and also received considerable radiation fram the crater, Stakes had been planted on this islard prior to the test to assist in the survev, but none of them could be found efter the blast. 1e extensive palm srove on the island had been conpletely destroyed. . Konitor ruards were established on YOKS-plus 4, and maintained ‘ continucusly until the island was closed just prior to CEORA test. Their presence considerably facilitated the work of the engineers in clearing evidence of blast effects fron the island, Samples of water obtained fron 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 CEBRA test, and the survey of iagoon currents off this island had already begun, ZEBRA Test A large area of fall-out was observed fran the air extending; out into the lagoon on an acimuth of 280° franz the zero point. This area vas 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 snagszing of the land cable made it impossible to 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 sreater radioacticity than had been met on ~ B-« Qn * bus aston Joen et aa I Mite fol So he ae a eeraetnTrt [7-2