be exceeded without careful consideration of the reasons for doing so, and that every effort should be made to encourage the maintenance of radiation doses as far below these guides as practicable. To comply with these standards, certain conditions must be met. First, the basic FRC recommendation is iA} "...that the yearly radiation exposure to the whole body of individuals in the general population...should not exceed 0.5 rem."/ The FRC recognized, however, that exposure of individuals may be difficult to monitor under some circumstances; thus they suggested that the limit to individuals may be met by the use of average limits to the popualtion. Second, therefore, the FRC indicated that:""Under certain conditions, such as widespread radioactive contamination of the environment, the only data available may be related to average contamination or exposure levels. Under these circumstances, it is necessary to make assumptions concerning the relationship between average and maximum doses. The Federal Radiation Council suggests the use of the arbitrary assumption that the majority of individuals do not vary from the average by a factor greater than three. Thus, we recommend the use of 0.17 rem for yearly whole-body exposure of average population groups... It is critical that this guide be applied with reason and judgment. Especially, it is noted that the use of the average figure, as a substitute for evidence concerning the dose to individuals, is permissible only when OtheFederalRadiation Council, in Report No. 1 (see footnote 4, pp. 26-27), stated that the guidance should not be exceeded unless "...a careful study indicates that the probable benefits will outweigh the potential risk." T5ee Note 4, p. 26.