to the depth of the gland. The return of the Rong2lapese to their home island in 1957 resulted in exposure to low levels of radionuclides in their environment. This is discussed in Chapter Ll 12.6 Acute Effects Examinations were carried out over a 72 day period initially followed by re-examinations at 6 months and then on an annual basis. compared with Marshallese people who were not exposed. Findings have been Since 1957 over 200 Rongelap people who were away from the island at the time of the accident have since returned to live with the exposed people. This group has formed an excellent comparison population. 12.6.1 Penetrating Gamma Radiation. During the first 48 hours typical radiation induced gastrointestinal symptoms were associated with their gamma radiation exposure. About two-thirds of the Rongelap people experienced anorexia and nausea and a few vomited and had diarrhea. more heavily exposed group only. These symptoms were noted in the Following their evacuation from Rongelap the people appeared well until the development of skin lesions 2 weeks later. However, when first examined on the third day, it was apparent that significant radiation exposure had occurred in view of the lowered lymphocyte counts. Serial hematological determinations including total white count, differential, platelet count and hematocrit revealed that the hemopoietic depression was most marked in the 64 people on Rongelap who had received 175 rads, less marked in the other *roups receiving less exposure. The average leukocyte and platelet counts are shown graphically in figures 7, 8 and 9. 50071306 The first counts on the Rongelap group