C2 (1) wo where x) = gamma or beta decay rate at time t,;, and x2 = gamma or beta decay rate at time to. m = decay exponent During early times post BRAVO and for short time intervals of a few hours it seemed Miller's decay exponents may have departed significantly from the standard value used for planning fallout activity decline (m = -1.2) and thus his tabulations described the early decay of BRAVO fallout adequately. These values for m at different times post detonation of BRAVO were listed in Table 2. The overall decay exponent calculated from Miller's data for the period one hour to sixty days post detonation was -1.2 and agreed with the standard value used for decay of unfractionated fission products.” Thus, the impact on exposure rate due to non-fission nuclides was not folded into Miller's tabulations and further study was needed to establish BRAVO decay (0C68). Surveys performed by the crew members of the USS PHILIP, the ship dispatched to evacuate Rongelap Island, have recorded an exposure rate level for Rongelap village of 1,473 mR nv average and 1,900 mR h_ 1 naximum at 2.2 days post detonation (COMTASK GROUP 7.3 Disp 0208482 of March 1954, 0C68). A similar but less precise statement of the exposure rate at the time of evacuation was given by Sharp (Sh57). In order to reconstruct the BRAVO exposure rate decline prior to evacuation and not use standard decay exponent (m # -1.2) additional information about the arrival time and nuclide composition of the BRAVO fallout activity was derived from Bikini Ash measurements.