had diarrhea. At this time many also experienced itching and burning of the akin and a few complained of lacrimation and burning of the eyes. Follow ing this, the pecple remained asymptomatic until about 2 weeks after the accident, when cutaneous lesions and patchy Joss of hair developed due to beta irradiation of the skin. Hematological examinations showed increasing depression of peripheral blood clements, and redio=-chemical examinations of the urine revealed the presence of detectable radioactivity in the samples. During the first few months many of the people showed a slight weight loss. It is not known if this was associated with irradiation effect or enviromental change. A. Hematological findings Figures 1 and 2 show chronologically the changes (in absolute mean counts) that have occurred in peripheral blocd elements of the 64 Rongelap people who received the largest dose of radiation, Simllar but less marked changes have occurred in the 18 Rongelap people who were on Allingnae Atoll at the time of exposure. 1. “BC. The leukocytes largely reflected the changes that occurred in the neutrophiles (see Figure 1) and will not be discussed separately. Unexplained changes in the mean level of blood elements have occurred from year to year in both exposed and unexposed populations. 2. Neutropbiles. During the first few weeks after exposure, the neutrophiles fluctuated considerably, then gradually fell to a low of about 50% of the comparison population at about the sixth week. (Figure 1). Ree covery was slow, and it was not until the one year examination that the counts returned to the comparison population level and have been found to be essentially the same as the unexposed group at i, 2, 3, and 4 years postexposure. -5=