A. Early Observations Whole-body gamma exposure in the Rongelap and to a lesser extent in the Ailingnae people resulted in transient anorexia, nausea, and vomiting. Depression of blood leukocytes and platelets to about half normal levels by 4 to 6 weeks was not accompanied by any detectable increase in infections or bleeding tendency, and there was no associated mortality. The exposed Utirik population had no early gastrointestinal symptoms, and only a slight depression of blood platelets was detectable on a statistical basis. Recovery of blood elements to near normal levels was evident by one year, though a slight continuing lag in complete recovery was noted in the Rongelap people during the first decade. Fallout deposition on the skin resulted in transient superficial radiation ("beta") burns and spotty epilation of the head in about 90% of the Rongelap people. Skin findings were less prevalent in the Ailingnae people and absent in the Utirik group. Of the spectrum of radionuclides absorbed internally, only the isotopes of iodine exceeded the maximum permissible concentratioa and resulted in de— tectable effects later. No early symptoms due to the internally absorbed nuclides were noted. Radiochemical urine analyses at 6 mnths showed the pres— ence of barely detectable radioactivity. B. Late Observations The general health of the exposed Marshaklese pesple (except for abnor malities associated with thyroid injury) has remained good and about the same as that observed in the unexposed populations examined. Vital statistics sug- gest that mortality and fertility rates have been about the same in the ex~ posed as in the umexposed people. During the first four years there appeared to be an increase in incidence of miscarriages and stillbirths in the exposed Rongelap women, but this observation was uncertain in view of the small numbers involved. Genetic studies and examinations of the newborn did not reveal any detectable abnormalities in the children of exposed parents that might have been related to radiation exposure. Probably related to radiation expo— sure was the finding of a slight increase in chromosomal aberrations in the lymphocytes of some Rongelap people at 10 years after exposure. No inc-ease in degenerative diseases (cardiovascular, arthritis, neuromuscular) or diabetes has been detected in the exposed people. Ophthaimological examinations (including slit-lamp studies) have not shown any remarkable differences in eye abnormalities between exposed and unexposed greups. So radiogenic cataracts have been noted. In 1972 a Rongelap male, exposed at one yeax of age, died of acute myelogenous leukemia, and another Rongelap male died from carcinoma of the stomach. These diseases may have been related to radiation exposure. ¥o other malignancies (except for thyroid carcinoma) have been noted which were likely to be related to radiation exposure. %> skin malignancies have been detected. The most widespread late effect of fallout exposure in the Marshallese has been the development of thyroid abnormalities - besign and malignant neoplasms and hypofunction of the gland. These, as well as growth retardation - 86 -