ysis of 137¢g, Four persons visited Argonne from Rongelap and, in addition, pooled urine samples from both atolls were analyzed radiochemically for 13706 and 905. Subsequent Brookhaven National Laboratory expeditions by members of the Medical Department and Safety and Environmental Protection Division utilized whole body counting and radiochemical analysis of urine and blood samples to identify and quantify the radionuclides that were present in the body. The re- sults of these radiological measurements are given in terms of body burden in Tables 1 and 2. Throughout this paper the units of quantities are SI derived and those which are accepted for use with the SI for the time being. Thus both the Curie and the Becquerel may be used as units for the quantity activity. The aforementioned body burden tables illustrate adult mean values for Rongelap and Utirik. of age. An adult, as classified here, was a person over 16 years The mean body mass in this age interval was 60 kilograms. The observed body mass versus age distribution is shown in Figure 1 for Rongelap residents. The same body mass versus age distribution was observed at Utirik. Because of the paucity of measurements at Utirik, information on 60, 6374, and 93 5@ was in some instances derived from the ratio of adult mean body burdens between Rongelap and Utirik. A mean ratio of 2.6 was observed in body burdens for 65 ~~Zn, 90 Sr, and 137¢, after they reached their maximum values. The Standard deviation of this ratio was 15%. In the following analysis, personal body burden histories and residence intervals, in conjunction with contemporary dosimetric models, are used to estimate internal dose. Dosimetric distributions were constructed from the results and a summary of the derived activity ingestion rates and dose equivalents was provided for various subgroups of the population. Additionally, exposure rate history curves were constructed for each atoll for the period following the