I. 7 Introduction This report is written in support of a petition bv the Natural Resources Defense Council to the Environmental Protection Agency (EPA) and the Atomic Energy Commission (AEC) requesting (1) a reduction of the existing radiation protection standards applicable to the internal exposure of man to insoluble alpha-emitting hot particle- and (2) the establishment, with respect to such materials, of standards governing the maximum permissible concentrations in air and * Maximum permissible surface contamination levels in unrestricted areas. Before proposing modifications to existing radiation protection standards related to plutonium exposure!, we 1 review in the following section the gravity of the public health concern as plutonium becomes a principal article of commerce in the nuclear power industry. 1/ While much of this report focuses narrowly on plutoniun-235, the discussion is, nevertheless, germaine to all radionuclices in insoluble particles with a hich specific activity. (The definition of specific activity and other technical terms in this report are given in the Glossary). The justification for focusing on plutonium has been artly stated by the Inter- National Commission on Radiological Protection (ICRP): "the emphasis on plutonium is clearly a reflection of the gerneral consensus that, in terms of amount available, projected usage, extent of anticipated accidental human exposure, anc radiotoxicity, plutonium is the most formicadle radionuciice in the pericdic table." [ICRP Publication 19, of Compounds of Plutonium and Other Actniacs,” it "1972, p.l.). "The Metado_licn Pergamon Prees,