by helicopter. The principal vessels of Task Group 7.3 returned to Fniwetok and task groups reorganized and prepared to resume Bi- kini operations from the afloat base. During the early post- SHor/ period, critical personnel re- ceived the maximum permissible exposure (MPE) of 3.9 roentgens and a request was made by CTG 7,3 that the MPE be increased to 7.8 roentgens, These included certain helicopter pilots and plane captains, boat operating personnel of the Task Group 7.3 Boat Pool, and flight deck personnei of the BAIROKO, Many personnel aboard the PHILIP were also exposed and during the remainder of the Operation this vessel was utilized outside the vicinity of the shot atoll except in emergencies, In a letter to CTG 7.3, dated 23 March, CJTF SEVEN approved the recommendation to increase the MPE to 7.8 roentgens for critical personnel listed above. To the east of Bikini, between 166 © and 173° east and between 5° and u,° north, there are some thirty Trust Territory-administer-ed atolls and islands of the Marshall chain, The safety of these populated islands has always been an important considerationin the final decision to detonate atomic devises or weapons in the PPG. As the size of the device increases, the possible radiological nazard likewise increases and CJIF SEVEN recogrized this as a sige nificant CASTLE operational fastor from the beginning, Although pre- shot evacuation of natives for any of the CASTLE detonations was not considered necessary, preparations were made to accomplish such if the need should arise, The Navy Task Group was assigned the respon-