Globusz^® Publishing 

The safety and monitoring report lists film badge readings for about 700 individuals who participated in Project TRINITY from 16 July 1945 to 1 January 1946 (1). This list includes both military and nonmilitary personnel who were involved with the TRINITY operation and postshot activities. However, records are available for only 44 of the 144 to 160 members of the evacuation detachment (1). In addition, some of these film badge listings may be for personnel who were only peripherally involved with TRINITY activities, such as family members and official guests who visited the site.

According to the safety and monitoring report, by 1 January 1946, 23 individuals had received cumulative gamma exposures greater than 2 but less than 4 roentgens. An additional 22 individuals received gamma exposures between 4 and 15 roentgens. Personnel who received gamma exposures exceeding 2 roentgens represent less than six percent of the Project TRINITY participants with recorded exposures. As described below, these exposures generally resulted when personnel approached ground zero several times (1).

Information is available regarding the activities of some of these personnel. One of the drivers of the earth-sampling group's lead-lined tank, an Army sergeant who traveled three times to ground zero, received an exposure of 15 roentgens. A second tank driver, also an Army sergeant, received an exposure of 3.3 roentgens. Three members of the earth-sampling group, all of whom traveled in the tank to ground zero, received exposures of 10, 7.5, and 5 roentgens. An Army photographer who entered the test area six times between 23 July and 20 October received 12.2 roentgens (1).

Four individuals involved with excavating the buried supports of the TRINITY tower from 8 October to 10 October 1945 received gamma exposures ranging from 3.4 to 4.7 roentgens. Film badge readings for this three-day period indicate that the two individuals who operated mechanical shovels received 3.4 and 4.3 roentgens, while the two who supervised and monitored the excavation received exposures of 4.2 and 4.7 roentgens. The individual receiving 4.7 roentgens during the excavation operation had received 1.3 roentgens from a previous exposure, making his total exposure 6 roentgens (1).

An Army captain who accompanied all test and observer parties into the ground zero area between 1 September and 11 October 1945 received a total gamma exposure of 2.6 roentgens (1). The activities and times of exposure are not known for other personnel with exposures over 2 roentgens.

According to the dosimetry records for 1946, about 115 people visited the test site that year. No one ventured inside the fence surrounding ground zero, and no one received an exposure greater than 1 roentgen (1; 16).