natural background and medical procedures are applied to NCRP and FRC recommendations, ICRP developed the concept of "acceptable risk." Unless man wishes to dispense with activities involving exposures to ionizing radiation, he must recognize that there is a degree of risk and must limit the radiation dese to a level at which the assumed risl is deemed to be acceptable to the individual and to society in view of the benefits derived fron such activities. For planned or controlled exposures of individuals and populations, the ICRP has recommended the term "dose linit." Recommended dose limits are thousht to be associated with a very lov degree of risk. For unplanned -——- exposures from uncontrolled sources the tern "action level" is recommended. In general it will be appropriate to institute countermeasures only when their social cost and risk will be less than those resulting from the exposure, Setting of action levels is the responsibility of national authorities. It is not desirable to exposure members of the public to doses as higu as those considered to be acceptable for radiation workers because children are involved, members of the public do not make the choice to be cxposed, and menbers of the public are not subject to selection, supervision and monitoring, and are exposed to the risks of their om occupations. For planning purposes, dose limits for members of the nublic are set a factor of ten below those for radiation workers. 111-95