14 beyond the range of thermal and blast injury. Marshallese and Americans were accidentally exposed on islands in this area, receiving whole-body gammaradiation, beta radiation injury to skin, and minimalinternal contamina- tion. The highest dose (an estimated 175 r) was received by a group of 64 Marshallese. The dose of radiation received proved to be sublethal. Though there was significant depression of hemopoiesis, no clinical signs or symptoms developed that could be attributed with certainty to this effect. Prophylactic administration of antibiotics or other specific therapy was not found to be indicated. Skin lesions and epilation developed in 90% of the group beginning about two weeks after the exposure. The lesions occurred largely on exposed parts of the body not protected by clothing, and varying degrees of protection were also afforded those who remained in- doors or bathed during the fall-out period. Most of the skin lesions were superficial and exhibited pigmentation; dry, scaly desquamation; and rapid healing with little pain. Some lesions were deeper, exhibiting wet desqua- mation, and a few became secondarily infected. Treatment was largely palliative except for use of antibiotics for secondarily infected lesions. Histopathological examination of lesions showed changes consistent with radiation damage. Bluish-brown pigmentation was noted in the fingernails and toenails of the dark-skinned people but not in the white Americans. Minimal amounts of radioactive material were detected in the urine. The internal deposition was insufficient to contribute significantly to the acute reaction, andit is believed there is no long-term hazard. Examinations conducted one year after the exposure revealed these people to be in generally good health. Slight depression of lymphocytes and platelets persisted. A few pigment aberrations and minimal atrophy remained at the site of the deeper skin lesions. Printed and Published in the United States of America 9012102