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Chapter I INTRODUCTION The potential effects of ionizing radiation on human populations have been a concern of the scientific community for several decades. The oldest of the scientific bodies now having re- sponsibility in this area are the International Commission on Radiological Protection (ICRP), formed in 1928, and the National Council on Radiation Protection and Measurements (NCRPX a United States organization initially formed in 1929 as the Advisory Committee on X-ray and Radium Protection. Both have main- tained continuing studies of radiation protec- tion problems that are of special relevance to the work of this Committee. In the 1940,s with the establishment of the U.S. Atomic Energy Commission and its program, there was recognition of possible radiation problems and large-scale animal experiments were initiated. In the early 1950,s, as a result of the testing of nuclear weapons, public concern arose about the potential effects of ionizing radiation on human populations. In 1955, as a response to this concern, the President of the National Academy of Sciences (NAS) appointed a group of scientists to conduct a continuing appraisal of the effects of atomic radiation on living organisms. That study, entitled "Biologi- cal Effects of Atomic Radiation," was support- ed by funds from the Rockefeller Foundation and led to a series of reports by six committees issued from 1956-1963 and which are generally referred to as the BEAR reports. Also, in 1955, the General Assembly of the United Nations established the UN Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), which, among other tasks asso- ciated with monitoring and assembling reports of radiation exposure throughout the world, was "to make yearly progress reports and to develop a summary of reports received on ra- diation levels and radiation effects on man and his environment. . . ." (UNSCEAR 1969). The periodic reports issued by UNSCEAR (the lat- est in 1969), in accordance with its objective, have served as a review of worldwide scientific information and opinion concerning human exposure to atomic radiation. In 1959, the Federal Radiation Council (FRC) was formed to provide a federal policy on hu- man radiation exposure. A major function of the FRC was to "advise the President with re- spect to radiation matters, directly or indirect- ly affecting health, including guidance for all Federal agencies in the formulation of radia- tion standards and in the establishment and execution of programs of cooperation with States " The FRC published eight re- ports, the latest in 1967. In 1964, at the request of the FRC, the Na tional Academy of Sciences - National Re- search Council (NAS-NRC) established an Ad- visory Committee to the Federal Radiation Council within the Division of Medical Sciences of NRC. The Advisory Committee has contin- ued to review and evaluate available scientific evidence bearing on a variety of problems of radiation exposure and protection and to issue reports of its deliberations. The BEAR reports led to a basis for public understanding of the expected effects of the testing of nuclear devices that had occurred to that date and introduced the important concept of regulation of average population doses on the basis of genetic risk to future generations. These reports also emphasized medical-dental x-rays as the greatest source of man-made ra- diation exposure of the population. However, in the late 1960,s, concern arose that developing peacetime applications of nuclear energy, par- ticularly the growth of a nuclear power indus- try for production of electricity, could cause serious exposure of the human population to
radiation. Thus, in February 1970, the FRC asked the NAS-NRC Advisory Committee to consider a complete review and re-evaluation of the existing scientific knowledge concerning radiation exposure to human populations. This request from the FRC came about because of: (1) a naturally developing sequence of the Advi- sory Committee,s concern that there had been no detailed overall review since the BEAR re- ports; (2) new factors that might need to be considered, such as optional methods of produc- ing electrical energy and types of environmen- tal contamination different from those pre- viously encountered; and (3) a growing number of allegations made in the public media and before Congressional committees that the ex- isting radiation protection guides were inade- quate and could lead to serious hazard to the health of the general population. The NAS-NRC Advisory Committee, on 25 March 1970, accepted the task proposed by the FRC and subsequently enlarged its member- ship accordingly. On 2 October 1970, the Envi- ronmental Protection Agency (EPA) was estab- lished by the President,s Reorganization Plan No. 3 of 1970. On 2 December 1970 the activities and functions of the FRC were transferred to the Radiation Office of the EPA. Because the FRC had ceased to exist as a specific body, the NAS-NRC Advisory Committee requested a change in its title. The President of the NAS renamed the Committee, the Advisory Commit- tee on the Biological Effects of Ionizing Radia- tions (BEIR); functions, activities, member- ship, and staffing were not changed. The task accepted in principle by the NAS- NRC Advisory Committee on 25 March 1970 is specified below in detail as a part of the con- tract agreement between NAS and the Depart- ment of Health, Education, and Welfare signed 1 September 1970. "Independently and not as an agent of the Government, the Contractor shall furnish to the Department of Health, Education, and Wel- fare, for the Federal Radiation Council, con- sultation and advisory services on the evalua- tion and interpretation of scientific problems pertaining to the biological effects of ionizing radiation. In performing the work and services provided for herein the Contractor shall: 1. Review the scientific bases used for the evaluation of risks at low levels of expo- sure to ionizing radiations (Chapters III- VII) 2. Select the scientific basis it recommends the FRC use. (pp. 3-9) 3. Make such estimates of risk as it deems scientifically appropriate. (Genetic, Ta- bles 2, 3, 4; G & D, pp. 79-80, Somatic, pp. 89-90) 4. Clearly delineate the interpretations and meaning that can be attributed to the esti- mates of risks when they are made. (pp. 1- 3) 5. Consider a broad spectrum of exposure conditions and biological effects, includ- ing: a) exposure conditions relevant to the general public, (Entire report) b) exposure conditions relevant to the ra- diation workers, (p. 171) c) somatic risk evaluation, (Chapter VII) d) genetic risk evaluation, (Chapter V) e) teratogenic effects, (Chapter VI) f) effects on the environment as may affect man. (Chapter IV) 6. Utilize the services of experts drawn from appropriate fields of science, technology, and other professional competences se- lected on the basis of the Contractor,s judgement of professional competence and scientific objectivity." To carry out the required review and analy- sis, five subcommittees were formed to deal with the following subject areas: (1) general considerations, especially societal interac- tions, (2) environmental effects, (3) genetic ef- fects, (4) somatic effects, (5) effects on growth and development. 'Parenthetical references are to sections of this report particularly relevant to these points