-2during that time. Therefore, attempts to reconstruct the probable exposures during this period must be indirect. Knapp used the gamma-ray intensity above a contaminated field as an index of its I??? content @) . while the St. Louis Group used this and the beta-particle disintegration rate from fallout collection trays ©), and the fission yiera®), I used the observed beta activity in the air Knapp and the St. Louis Group were concerned chiefly with exposures in Southern Utah near the Nevada Test Site, because that was where the highest individual doses were indicated. My major con- cern was the North-Central portion of Utah, because it contained so many more people. During the 1963 Congressional Fallout Hearings, Dr. Eric Riess of the St. Louis Group and I both urged that a study be made of the irradiated Utah children. This study, supported by the U. S. Public Health Service, is now in progress. : Originally, the study had 2 objectives: and (2) estimation of radiation dosage. well, but the-dose program has lagged. (1) search for medical effects, The medical phase is progressing An unfortunate decision was made to neglect dosimetry unless significant medical effects could definitely be established. In my opinion, this is the most serious defect in an otherwise excellent study. Waiting for possible medical effects may forfeit forever the opportunity to make the best estimates of dose. Memories fade, records are destroyed, and these children will soon reach adulthood and scatter across the nation. Even if no effects appear, the exposures should be evaluated as accurately as possible. If a safe dose exists for 3! in children, proper study of the 250,000 irradiated Utah infants may provide the unique chance to establish it. In this paper I present lower and higher limits for the average doses received by Utah infants. I do this for 2 reasons. First, I hope that the uncertainty in these limits will stimulate interest in improving the dosimetry. Secondly, despite dose uncertainties, the indicated exposures are sufficient to justify continued study of the Utah children. DOS IMETRY Prior to the 1963 Fallout Hearings, I calculated the number of radiationinduced cancers predicted for the total population of 250,000 Utah children exposed to fallout [23+ as infants. I have never before published these