DUBLIC HEALTH agencies have the clear responsibility of balancing the hazards of radiation against the physiological and social values of its use. Historically, major public health programs were developed after it had been amply demonstrated that a health problem involving substantial mortality and morbidity existed. In the radiation field, however, the total number of deaths in the United States which may be directly attributed to excessive exposure to ionizing radiation has been less than the number of persons killed on our highways in a single weekend. Actually, the apparent evidence of a radiation health problem in the world today is so small that one may be justified in asking why it is receiving so much attention. There are a number of answers to this question. One of the most important is worldwide awareness of the capability for devastation of nuclear systems of even moidest proportions.