* "Compania" also appears as "Compana," "Campagne," or "Compagna" in various sources.
Project personnel not required to check instruments within the ground zero area stationed themselves in the three shelters or at other assigned locations. The military police at Guard Posts 1, 2, and 4 blocked off all roads leading into the test site, and the men at Guard Post 8, the only access to the ground zero area from the Base Camp, ensured that no unauthorized individuals entered the area (9; 12).
At 0100 hours on 16 July, military policemen from Guard Posts 3, 5, 6, and 7 met to compare their logs of personnel authorized to be in the ground zero area. The guards then traveled along the access roads to clear out all project personnel. As individuals left for their assigned shelters or stations, their departures from the test area were recorded in the military police logs. By 0200 the area sweep was completed, and the military police went to their shelters and stations. A final check of personnel was made in each shelter (3; 9; 12).
At the time of detonation, 99 project personnel were in the three shelters: 29 in the north shelter, 37 in the west shelter, and 33 in the south shelter. Dr. Oppenheimer, Dr. Bainbridge, and other key personnel awaited the firing at the south shelter, which served as the Control Point. Figure 2-3 shows the exterior of the south shelter; figure 2-4 gives an interior view of one of the shelters, most likely the south. Although most of the shelter occupants were civilians, at least 23 military participants were spread among the three shelters (1; 12).
The remainder of the test site personnel were positioned at the Base
Camp 16 kilometers south-southwest of ground zero, or on Compania
Hill, or at the guard posts. Important Government officials, such as
General Groves and Dr. Vannevar Bush, Director of the U.S. Office of
Scientific Research and Development, viewed the detonation from a
trench at the Base Camp. The Base Camp is depicted in figure 2-5.
The military police of Guard Posts 1 and 2 were instructed to be in foxholes approximately five kilometers west and north, respectively, from their posts. The military police of Guard Posts 3 and 4 were instructed to be in foxholes south of Mockingbird Gap. A radiological safety monitor was assigned to the group from Guard Post 4. Guard Post 5 personnel were to be in the south shelter, Guard Post 6 personnel in the west shelter, and Guard Post 7 personnel in the north shelter. The military police of Guard Post 8 remained at that post, 400 meters east of the Base Camp (9).
An evacuation detachment of between 144 and 160 officers and enlisted men was stationed near Guard Post 2, about 14 kilometers northwest of ground zero. These men were on standby in case ranches and towns beyond the test site had to be evacuated. Five radiological safety monitors were assigned to this detachment. Ninety-four men of the evacuation detachment belonged to Provisional Detachment Number 1, Company "B," of the 9812th Technical Service Unit, Army Corps of Engineers, from LASL. The identity of the remaining evacuation personnel has not been documented (3; 4; 8; 10; 15).
With the exception of the shelter occupants (99 personnel) and evacuation detachment (between 144 and 160 men), the number of personnel at the test site at the time of detonation has not been documented. Film badge records show that approximately 355 people were at the test site at some time during 16 July. The shelter occupants and 44 men of the evacuation detachment are on this list. It has not been possible to pinpoint the location of many of the remaining personnel. Some were at the Base Camp or on Compania Hill. Since many of these people returned to the test site after shot-time to work on experiments, their film badges registered exposures from residual radioactivity on 16 July. Based on the documented personnel totals, at least the following 263 individuals were at the test site when the device was detonated (1; 4; 8-10; 13; 15):
o 99 shelter occupants at shelters 9,150 meters north, south, and west of ground zero
o 144 to 160 officers and enlisted men of the evacuation detachment, located 14 kilometers northwest of ground zero near Guard Post 2