19 dosage. > This can be attributed to several factors, including greater sensitivity for portions of the bone where the nuclide is deposited, and greater importance of damaged tissue. These factors are taken into account in establishing maximum permissible values. Determinations of maximum permissible values for body burdens of the various radionuclides are based on two somewhat differing criteria. One criterion, as I have just discussed, is for the bone-seekers; the second, for the other radionuclides, is based on limiting the weekly dose to the organ where the nuclide concentrates to a value commensurate with the limitation for whole-body external exposure. Calcula- tions have been made for the gamut of nuclear-weapon-produced radionuclides and the results may be found in the NRRP report 'Maximum Permissible Amounts of Radioisotopes in the Human Body and Maximum Permissible Concentrations in Air and Water,'' U.S. Department of Commerce, National Bureau of Standards Handbook 53, March 20, 1953. This report was superseded by the NCRP Handbook No. 69 published in June 1959 and entitled ''Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and Water for Occupational Exposure.'' These calculations also are reflected in the ''Report of ICRP Committee on Permissible Dose of Internal Radiation (1959)'"' published in the 1960 issue of Health Physics.