24 days after the contaminating event. Analysis of the 24 day urines per- formed 2 years later showed that the samples also contained some sr and ce", sr? activity in the urine decreased from 12 d/m/l1 in the 24th day specimens to 0.34-1.41 d/m/1 in the 1957 specimens. Sr” analyses on urine samples taken in the 4 year survey have not been completed. The cs? uriw mary activity finctuated, decreasing from 174 d/m/l1 on the 24th day to 33 d/e/l in 1956, and then increasing to 137-370 d/m/l in 1957.° Prelimie nary analysis of the 1958 data indicate that the cs? activity in urine increased by a factor of 100 over the 1957 levels. (Two residents of Utirik Atoll who had been living on their island since several months after its accidental contamination in the 1954 fallout had urinary cs? actigities of 11,653 and 3,735 d/m/l in 1957.) Ags part of the 3 year post~-exposure survey 4 of the Rongelap people were brought back to Argonne National Laboratory where a more direct measurement of the internally deposited gamma emitting radioisotapes was obtained. (5) Cs 137 was identified as being the most prominent gamma 202 microcuries of Cs residents. 137 and ,03=,07 microcuries of Zn 65 \ in the Rangelap \ Two Utizik rasidents similarly measured had 0.22 and 0.41 mie crocuries of C5 137 and .482 and .229 microcuries of zn®* , 06) \ 6. We are grateful to Col. James Hartgering (MC) USA, Maj. Kent T. Woodward (MC) USA, Lt. Ariel Schrodt of the Walter Reed Army Medical Center, Dr. john Haricy and Mr. Edward Hardy of the New York Gperations Office of ABC, and Dr. Stan Cohn of US NEDL for assistance in radio chemical analyses. ~1j~ ee Analysis of the spectra indicated an average body burden‘ of ——e am aa ” a a cdiscovered, eee ES emitter and the presence of the neutroneinduced radionuclide zn®> was