Peo vnTech21h. 8% fFHE ce TheLoge rv® na ye" HEADQUARTERS 110479 GROUP 7,4, PROVISIONAL [Het Lent MAk-Abk (954 TASK APO 187, c/o Postmaster San Francisco, California . teoe 97 O | U, April 1954 MEMORANDUM FOR THE RECORD SUBJECT: 1. Evacuation of Rongerik After Shot BRAVO, Operation CASTIE Twenty-four (24) airmen and one (1) Warrant Officer of the Weather Reporting Element (Provisional), Task Group 7.4 were assigned to operate a weather station for JIF SEVEN on Rongerik Atoll, Marshall Islands, In addition this detachment operated a recording radiation — rate mter for the New York Operations Office, AEC, The purpose of the ‘ device was to masure and record any radioactive fall-out which might occur after an atomic detonation on either Eniwetok or Bikini Atolls during Operation CASTILE, This radiac station was one of several situated in the Pacific Ocean area as part of a general fall-out study. The instrument was capable of detecting a maximum activity of 100 mr/hr. Above that figure the instrument was inoperable. Mr M, R. Breslin, JIF SEVEN was the local representative of the New York Operations Office, AEC, 2. f Project 6.6, These personnel shared messing and housing facilities with 9 the Task Group 7.4 detachment, aO Sw ZO zQ 9 g Zo 3. Shot BRAVO was fired on 1 March 1954 at approximately 0640 local time on CHARLIE Island located in the northwest corner of Bikini OL zo oO Atoll. Atoll, E c oO Three (3) Army enlisted men assigned to Task Group 7.1 were stationed on Rongerik to operate an Ionosphere measurement station for a z ¢ 2 4. a 5 The ZERO point was approximately 130 nautical miles from Rongerik The following is a chronological sequence of messages amd deci- sions leading up to and through the evacuation of the personnel on Rongerik Atoll on 2 March 1954: a. Message No, 1: From Weather Detachment at Rongerik to JIF SEVEN, 1500, 1 March 1954 - “Attention Mr Breslin, Info Commander, Weather Reporting Element, Provisional. GR 12 MIKE over 100 CHARLIE - Over 100," Above message received AACS Communications Center, Eniwetok at 1543, 1 March, and delivered to US Army Communications Center, Eniwetok at 1547 (local tim) for transmission to JIF SEVEN, Paryy, Commander WREP GR 12" was in the body of the gmagea Test Services Unit, TC 7.4, was not informed é Because the "Info the Weather Element = 3 2 So