both islands were the same length and the air activity concentrations were equal then 95 times less exposure rate at Utirik Island would be anticipated not 9.5. Therefore, the fallout cloud duration at Utirik must have been longer, it was longer by a factor of 2 to 3 when compared to Rongelap. in fact It was not long enough to satisfy the known values of exposure rate and the estimated values of granule fall time and fallout duration. Therefore the air concentration at Utirik Island was calculated to be greater than at Rongelap for certain long lived nuclides (see I-131, Table 10). Peterson (see Section II) in an attempt to satisfy the exposure rate data and weather data indicated the cloud may have been blown back to Utirik which would in effect increase the overall fallout duration time rather than air concentration. The total fallout activity on the surface of Rongelap Island was still ten times greater than at Utirik Island regardless of air concentration during fallout deposition largely due to the rate at which granules fell to the surface. Airborne activity intakes were dependent upon breathing rate of individuals during fallout cloud passage. Breathing rate was assumed proportional to body mass as derived from reference data for persons less than 58 kg (ICRP74). Adult reference values for breathing rate (ICRP74) were assumed for Marshallese adults regardless of adult body mass. At Rongelap Island, BRAVO de- bris passed during the afternoon, a period of light physical activity for the population. At Utirik Island, the debris passed during the night, a period of rest- ing. At Sifo Island a period of light physical activity was assumed in order to estimate breathing rate. Values for airborne activity intake were compiled from data in Table 10 and breathing rate estimates and were given in Table 11. Body mass and corresponding age and breathing rate were also listed in Table 11. Om the basis of urine data it was determined that inhalation could 33