0070942 ESTIMATED THYROID DOSES & PRED ICTED HYROID CAEOF ARCHIVES IN UTAH INFANTS EXPOSED TO FALLOUT 1336 US ATOMIC ENERGY Charles W. Mays a ) oy! FD a RG Physics Group Leader, Radiobiolp | CO MMISSION -CP (rh. Anatomy Dept., U. of UtahVnreatioa DEM - Salt Lake City, Utah ABSTRACT: |,/¥?Q Tat 92 ¢5 The inadvertent exposure of about. PeOphQ0 Utah ing us phys = to average thyroid doses estimated at 1.3-10 tadsmayprovidea ma unique opportunity to establish the effects of low doses of ['3? irradiation in children. INTRODUCTION Iodine-131 is produced in nuclear explosions. If cows eat forage which is contaminated with fresh fallout, [2°91 appears in their milk. If a child drinks this radioactive milk, I?) concentrates in his thyroid gland and irradiates it. Infants are considered to be the critical members of the population... Dr. Robert C. Pendleton* was the first to discover that fallout from the Nevada nuclear tests of 1962 would cause significant contamination from radioactive I?3} in Utah GY| Following his vigorous urging that steps be taken to reduce the exposure, the Utah State Department of Health recommended: (1) transfer of cows from highly contaminated pasture to stored feed, and (2) diversion of highly contaminated milk from the fresh market ©) , protective action set a precedent: This it marked the first official attempt in this country to prevent the intake of fallout-contaminated food. In analyzing the 1962 incident I became fascinated with the implications of exposures from the previous years of testing. Unknown to me at the time, this problem was also being investigated through different approaches by Dr. Harold A. Knapp then with the AEC, and by members of the St. Louis Committee on Nuclear Information. Same conclusion: Working independently, we all came to the significant exposures were indicated. The problem was complicated enormously by the fact that F)?? was not properly recognized as a fallout hazard during the early years of testing (1951, 1952, 1953 & 1955), and, unfortunately, I?! was not measured in milk x 4 Associate Professor of Genetic and Molecular Biology and Head, Department of Radiological Health, University of Utah. feweT 8TY 65