5 y of the adults (1959)' differences between the | groups. The people appertension on the whole in the continental United 39)° showed no greatdifposed and the unexposed mieincidence as is seen in rs showed no remarkable ‘exposed and unexposed 1 ightly greater number aeculae, and corneal scars is nat known whetherths cance in relation to their ampobservations showed ‘haracteristic of radiation sual and accommodation appeared to be above the uv auon. no significant difterences exposed and unexposed neidence and severity of slightly greater in the exnown whether or not this diation effects. The poor ~ ~rved in the Marshallese umely, high caries rate in re peridontal lesions in ind loss of alveolar bone), in the aged. Radiation exa» have affected developing i children. Various parameters usu- were measured or esti- skin looseness, elasticity, ang of the hair and baidisual acuity, and arcus ascular changes including ees of peripheral and ret~omuscular function; and “son of these measure- The one case of cancer that developed in the exposed group occurred at 5 years after exposure, too soon, it is believed, to bear any particular relation to radiation exposure. Leukemsa surveys including physical findings, studies of white cell counts and types, alkaline phosphatase staining, and basophil-counts of 4000 white celis showed no evidence of leukemia or leukemic tendency. One child in the irradiated group has hadslightly elevated basophils but no other positive findings. The cardrovascular and arthritis surveys, as well as the general results of the physical examinations, have not shown any apparent increased incidence of degenerative diseases in the exposed people. No radiation-induced cataracts have been obeerved in any of the exposed people. Genetic effects have not been specifically studied because of the smail numberof peopie involved. No apparent radiation-induced genetic changes have been dete::ted on routine physical examinaton in the first-generation children of exposed parents, with the possible exception of suggestive evidence of increased miscarriages and stillbirths in the exposed women and theslight retardation of growth noted in the male children of exposed parents. 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 weeks after 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: thev exhibited pigmentation and dry, scaly desquamation, and were associated with little pain. Rapid healing and repigmentation fol- lowed. Some lesions were deeper, showed wet des- quamation, and were more painful. A few burns became secondarily infected and had to be treated with antibioucs. Repigmentation of the lesions anexposed individuals of gradually took place in inost instances, and the skin appeared normal within a few weeks. How- by use of an average per- unued to show lack of repigmentation with vary- owed no apparent differscore was calculated for mg effects of radiation have noted, the mortality rate the exposed as in the un- ever, in about 15°c of the peopie, deeper lesions, particularty noted on the dorsum ofthe feet. con- and atrophyat the site of the former burns. During the past several years an increased number of pigmented maculae and moles have been noted in previously irradiated areas of the skin, but these have appeared to be quite benign. Numerous aistopat.ological studies have been made,'''” and the changes found have been consistent with radiation damage. At no time have changes been observed cither groasly 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 6 months. No further evidenceof epilation has been seen. An interesting observation noted duringthe first few months after exposure was the development of bluish-brown pigmentation of the semilunar areas of the fingernails and toenails in about 90% of the people. By 6 months this pigmentation had disappeared, having grown out with the nail. The cause of this phenomenonhas not been explained. INTERNAL IRRADLATION Radiochemical analyses of numerous urine sam- ples of the exposed population showed internal ab- sorption of radioactive materials, probably brought about largely through eating and dnnking contaminated food and water and to a lesser extent through inhalation. During the first few days when the bodylevels were at their highest, the maximum permissible concentrauions were approachedor slightly exceeded only in the case of strontuuum-89 and the isotopes of iodine. The con- centrations were believed to be too low to result in anyserious effects. Bodvlevels fell rapidly, so that by 2 and 3 years post exposure. they were far below the accepted maximum permussible level; by 6 months activity in the urine was barely detectable In 1958 analvses of bone samples on one of the men who died sho ved 3.7 stronuuum-90 units/g calcium. Beginning in 1957, gamma spectroscopy by use of a low-level counting chamber was added to the techniques of radiochemical analysis. The return of the Rongelapese to their home island ing degrees of scarring and atrophyof the skin. By (which atter careful survey was considered safe for habitation, despite a persisting low levei of radio- 6 years the onlyresidual effects of beta radiation active contamination) was reflected in a rise in varying degrees of pigment aberrations, scarring, uon of certain radionuclides. During the years of the skin were seen in 10 cases which showed their body burdens and increased urinary excre-