Ge present at the time oPexposure, who died 2 vears after the accideny2)_a 78-vear-old man who died, 3 vears after exposure, of coronary heart disease complicating diabetes; and (3} a 36-vear-old man whodied of acute varicella, + vears after exposure, who had received only 69 r, having been on Ailiggnae at the time of the fallout. There was no apparent relationship between any of these deaths 4nd radiation exposure, and mortalityin the exposed group did not appearto be greater than in the unexposed population. It was difficult to evaluate the effects onfertility. However, a number of apparentiv normal babies were born during the 4-year period, and there has been no discernible fall in birth rate. A slightly higher number of miscarriages occurred in the exposed women than in the unexposed group: this will be further evaluated in the present report. No opacities of the lens or other eve changes have been found that could be related to radiation. Studies on height, weight, and bone age seemed to show a slight degree of retardation in growth and development in the exposed children. However, the small number ofchildren involved, and a later finding that exact ages of some of the children werein doubt, has resulted in a re-evaluation of these data based on more reliable age determinations. BETA IRRADIATION OF THE SKIN It was impossible to get an accurate estimate of the radiation dose to the skin. Beta burns of the skin and epilation appeared about 2 weeksafter exposure, largely on parts of the body not covered by clothing, About 90% of the people had these burns, and a smaller number developed spotty epilation of the scalp. Most of the lesions were superficial; they exhibited pigmentation and dry, scaly desquamation, and were associated with little pain. Rapid healing and repigmentation followed. Some lesions were deeper, showed wet desquamation, and were more painful. A few burns became secondarily infected and had to be treated with antibiotics. Repigmentation of the lesions gradually took place in most instances, and ‘ the skin appeared normal within a few weeks. However, in about 15% of the people, deeper lesions, particularly noted on the dorsum of the feet, continued to showlack of repigmentation with varying degrees of scarring and atrophyof the skin. At 4 years the only residual effects of beta radiation of the skin were seen in 12 cases which showed varying degrees of pigment aberrations. scarring, and atrophyat the site of the former burns. Numerous histopathological studies have been made,‘ '? and the changes found have been consistent with radiation damage. At no time have changes been observed either grosslv or microscopically indicative of malignant or premalignant change. Spotty epilation on the heads was short lived, regrowth of hair occurring about 3 months after exposure and complete regrowth of normal hair by six months. No further evidence of 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, this pigmentation hadlargely grown out with the nail and had disappeared in most cases. The cause of this phenomenon has not been explained. INTERNAL IRRADIATION . o Radiochemical analyses of numerous urine samples of the exposed population showedinternal absorption of radioactive materials, probably brought about largelv through eating and drinking contaminated food and water and to a lesser extent through inhalation. During thefirst few days when the body levels were at their highest, the maximum permissible concentrations were approached or slightly exceeded only in the case of strontium-89 and the isotopes of iodine. The concentrations were believed to be too low to result in any serious effects. Body levels fell rapidly, so that by 2 and 3 years post exposure, they were far belowthe accepted maximum permissible level; by 6 months activity in the urine was barely detectable. The return of the Rongelapese to their home island | which after careful survey was considered safe for habitation, despite a persisting low level of radioactive contamination) was reflected in a rise in their body burdens and increased urinary excretion of certain radionuclides. Beginning in 1957, gamma spectroscopyby use of a low-level counting chamber was added to the techniques of radic. aemical analysis. This, along with radiochemical analysis of urine samples, showed an increase in body burdens of cesium-137 by factors of up to 100 and of strontium-90 by a factor of 10 to 20: and some increase also in zinc-65, since the re-