(Frc) *°, The MPC, is included in the ICRP recommendations’ ~ and is also an AEC radiation standard’. Of the standards -n Table I only the MPC, is designated in the AEC regulations. HTowever, this MPC, corresponds to that tabulated in ICRP Publication 213 which is derived on the basis of the MPLD listed in Table I. he mpip?4 , The MPLB is not included in either the recommenda- tions of ICRP, NCRP, regulations. The MPLB is also derived on the basis of the guidelines of FRC, In summery, in AEC regulations) or the AEC in Table I the MPCa (designated is consistant with the MPLD and MPLB. In Table I the MPLD applies to all forms of ionizing radiation. The MPLB and MPCs apply specifically to Pu-239 in insoluble form!?. 10/ FRC Report No. 1, Op. cit., p. 38. The FRC has been wOlisned and its ducies transferred to EPA. . 11/, “ICRP Publication 2, Report of Committee II on Permissible Dose for Internal Radiation, Pergamon Press, New York, 1960. . [Appeared in Health Physics, Vol. 3, Pergamon Press, June 1960.) 12/ 10 CFR 20, Appendix B. 13/ ICRP Publication 2, Op. cit. - 14/ Mann, J.R. and A.R. Kirchner, “Evaluation of Lung Burden Following Acute Inhalation of Highly Insoluble Pu02," Health Physics, Vol. 13, 1967, pp. 877-882. 15/ The MPLB could apply to most other alpha-emitting radionuclides with long half-lives, since the alpha particle energies do not differ appreciably from the Pu-239 alpha energy.