Pennie TR of 3. Judging from past experience at the Nevada Test Site, 4t would not be operationally feasible to limit exposures to 10 roentgens in 30 years. The situation becomes one of facing the problem frankly and in the interests of the National Defense defining the degree of risk, as the Commission has done in the past. It would appear that a reasonable figure would Ile somewhat between the 10 and 50 roentgens per 30 years, The acceptable value of exposure within this range is dependent upon one's philosophy with respect to the imperativeness of the nuclear testing program since even the highest value (50 roentgens in 30 years) would not be considered a dangerous exposure in terms of the individual's health nor of major consequence genetically. (Fifty roentgens might double the mutation rate, but this would be for a relatively small number of persons in terms of the general population,) Based on such reasoning we are recommending that the operational guide be arbitrarily established at 10 roentgens in a period of 10 years with the first of the successive ten year periods starting in the spring of 1951. first nuclear tests in Nevada.) (The date of the This criterion should not be con- strued as a maximum limit beyond which serious effects might be expected, but rather it should be thought of as an operational guide. 4, The operational feasibility of 10 roentgens in 10 years may be estimated by noting that during the five years of testing at Nevada Test Site the highest total accumulated: exposure to any community has been about four and one-half roentgens {about 15 people living at a motor court received about seven to eight roentgens). This might suggest a degree of ease in meeting the criteria that does not in fact exist. The relatively low exposures are the result of the most exacting plans and procedures for ~ 4 - Appendix "A"

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