case of thyroid cancer per 230 children; a minimum of one case in five thousanc n. Not unless many more children in the Marshall Islands had been exposed to iodine 131 fallout would the absence of cancer or other thyroid abnormalities there suggest that cancer er other thyroid abnormalities would be unlikely in the Utah children. picture that can be reliably screened out of a ‘welll’ populatior — ‘ recourse to intensive study.” The proviein .s certainly a unique, complex and difficult one, but it is of such importance that neither difficulty nor cost should be allowed to stand in the way of expanded and, if necessary, intensive studies. Dr. Wolff does not comment on the possibility of improving the dosimetry. If this could be done and small areas of high dosage identified, the intensive studies might first be concentrated in those areas. The comments from Dr. Wolff of the Radiological Health Department of the U.S. Public Health Service (p. 2) describe what is currently being done and what is planned in the search for pathological effects. The small expansion of the present field study in southern Utah and the collection and analysis of Utah and Nevada records of thyroid surgery are both useful steps. Whether “extensive epidemiologic studies” should be other questions may have to be asked; other studies designed. This is a challenge, not only to the Public tioned by Dr. Wolff because the present field study is difficult and costly, with “no characteristic clinical community who have an interest in the problem and a competence in one of the related disciplines. designed on the basis of Dr. Mays’ dosimetry is ques- Robert A. Conard Robert A. Conard is head of the Marshall! Island Surveys at the Brookhaven National Laboratory. The studies of the Utah children proposed by Dr. Mays are worthy of consideration. However, the task of reconstructing the thyroid doses in this population due to fallout from detonation of different nuclear devices over the past years would appear to be extremely difficult, if not impossible. Also the logistics of instituting retrospective and prospective studies in this population of children are formidable. The diagnosis of radia- tion-induced thyroid lesions would be extremely difficult to separate from thyroiditis and other prevalent thyroid conditions in this population without careful pathologic and other studies. The Salt Lake City population of children is quite large for the thorough studies that would be necessary. Perhaps concentration of efforts on the more heavily exposed Washington Countychildren would result in more meaningful information. In our studies in the Marshall Island people exposed to fallout in 1954, twelve years ago, we have noted over the past few years the development of thyroid abnormaljties in fifteen of nineteen children exposed at less ‘than ten years of age (thirteen with benign thyroid nodules and two with hypothyroidism).' One adult developed cancer of the thyroid. It should be pointed out that the incidence of thyroid disease is quite low in the Marshall Islands. Although dose esti- mates are not precise, it was calculated that the thyroid glands of the young Marshallese children received in the range of 700-1400 rads from radioiodines internally absorbed and in addition 175 rads from gammaradia- tion (similar to x-rays). These doses are considerably Scientist and Citizen In looking for thyroid damage within the “well” population, new and unorthodox methods may have to be tried; new screening procedures sought. If the questions now being asked are not yielding the answers, Health Service, but to all members of the scientific higher than those received by the Utah children. More pertinent is the absence thus far of any thyroid ab- normalities in 40 other Marshallese children, on a dif- ferent island, exposed in the same age range, who received an estimated 55-125 rads to their thyroid glands, and also lack of thyroid abnormalities in six children, on still another island, that received an estimated 300-600 rads to their glands. These doses are probably also higher than those received by the Utah children. Therefore, based on the Marshallese experience, it does not seem likely that an easily detectable increase in thyroid abnormalities will be found in the Utah children. However, it should be pointed out that the numberof exposed Marshallese children is too small to establish a low or threshold dose of induction of thyroid abnormalities. If thyroid dosimetry proves satis- factory and thyroid studies could be effectively pursued in the Utah children, the data collected, even if of a negative nature, would be valuable. REFERENCE 1. R. A. Conard, J. E. Rall, and W. W. Sutow: Thyroid nodules as a late sequela of radioactive fallout in a Marshall Island population exposed in 1954. New England Journal of Medicine 274: 1392-1399, June 23, 1966. Robert C. Pendleton Robert C. Pendleton is head of the Radiological Health Department of the University of Utah. Dr. Mays has covered the problems relative to reassessing the hazard to children in the Utah area admirably, and my comments will be concerned with the ecological factors that have to date not been taken DOE ARCHIVES 1