to employ time-rate of growth and decline graphs. Accordingly, curve graphs have been prepared for the following segments of proving ground population: Figure 8. Eniwetok Island, TG 7.5 Personnel Parry Island, Task Group Personnel Figure 9. Figure 10. Rojoa Island, Task Group Personnel Figure 11, Eniwetok Atoll, TG 7.land TG 7,5 Personnel Figure 12. Bikini Atoll, All Task Groups' Personnel Based Ashore. Figure 13. Jobsite Personnel for Both Atolls by Months from 15 Octo- ber 1952 (IVY) through 15 June 1954. The camp facilities and services provided were adequate with one exception: On 1 March 1954 the initial experiment (BRAVO) was executed and the original plans were to re-occupy sites Enyu and Eninman on the day of the first shot. However, due to the widespread destruction of facilities on these two sites and to the high degree of radioactivity that prevailed immediately following this test, it was deemed advisable to return all personnel to Eniwetok Atoll. The disposition of Task Group evacuees is outlined in Part IJ, 1.6 Significant Events. All personnel were clothed, fed and shel- tered, but the existing billeting facilities were increased 33 percent above the maximum capacity, resulting in some inconveniences, (Task Group 7.3 personnel remained afloat.) These conditions existed for a few days only; personnel were later returned to Bikini where future tests were conducted from aboard ship. _Some H&N personnel were returned to the States because major construction work had been completed, CHAPTER 2.1 2. CONSTRUCTION ACTIVITIES COMMENTS Prior to Operation IVY, there was growing concern over the limitations of Eniwetok Atoll for detonation of very high yield thermonuclear devices. As early as May 1952 the Task Force command, the staff of the Los Alamos Scientific Laboratory, and AEC test personnel were investigating the pros and cons of firing very high yield test units at locations other than Eniwetok, and the possibility of reactivating Bikini was being discussed. Practicability of utilizing one of several uninhabited islands in the Marshall, Caroline and Mariana Island groups was investigated and a survey of the Bikini Atoll as to its suitability for executing a very high yield detonation was conducted. The conclusion was reached that utilization of Bikini Atoll was most desirable from the standpoint of available land, isolated location, operational efficiency and economy. On 11 September 1952, concurrent with appropriate action with representatives of the Department of Interior and the State De- . partment, the Atomic Energy Commission approved use of Bikini for CASTLE, The Commission stipulated that there must be no permanent construction at Bikini and that maximum possible economy and use of temporary and portable equipment must be the rule. Beachhead operations at Bikini on 1 October 1952, as proposed, were authorized at the same time. 26