some degree of residual skin change largely in the rials, probably brought about largely through form of pigment aberrations with atrophy and scarring. Numerous histopathological studies have eating and drinking contaminated food and water. Calculations of the body burdens of these mate- been made, and the changes found have been consistent with radiation damage. However, at no rials, however, showed that the concentrations time have changes been observed either grossly or microscopically indicative of malignant or premalignant change. The spotty epilation on the heads was shortlived, regrowth of hair occurring about 3 months after exposure and complete regrowth of normal hair by 6 months post-exposure. No further evi- denceof epilation has been seen. An interesting observation was the appearance of a bluish-brown pigmentation of the semilunar areas of the fingernails and toenails in about 90% of the people beginning about 3 weeks after exposure. By 6 months, however, the pigmentation had largely grown out with the nail and had disappeared in most cases. The cause of this phenomenon has not been explained. Internal Irradiation Radiochemical analysis of numerous urine samples of the exposed population showed some degree of internal absorption of radioactive mate- were too low to result in any serious effects, and the levels found at 2 and 3 years post-exposure were far below the accepted maximum permissible body level. The results of numerousradiochemical examinationsof the urines over the past 4 years, and of gamma spectroscopy over the past 2 years, will be reviewed in greater detail below. Present Survey BACKGROUND MATERIAL Organization The medical team consisted of 8 physicians, 5 scientists, and 6 technicians from various labo- ratories in the United States. A Marshallese practitioner and 2 medical technicians from Majuro Atoll assisted the team, as did someofthe Rongelap people (see Figure 2). A group ofsix scientists from the University of Washington, headed by Dr. E.E. Held, accom- paniedthe team to collect soil, marine, and plant 3 fo a) “<"y aS Cri Figure 2. Medical team personnel.