The following assumptions are nade in estimating radiation doses to the lungs. &. Twenty per cent of the inhaled activity is deposited. B. There will be no elimination of particles during their radio-~ active lifetines. There is uncertainty as to the biological half-life of particles in the lungs. In those communities showing the highest concentrations of fallout, the pesk of airborne material (which accounted for the greatest percentage of total fallout) occurred only « few hours efter detonation. If one assumer a radiological decay according to t7)*< and a biological half-life of say 30 days, the omission of biological half-life would not affect seriously the computed total dose. C. DGEINY. Ali of the activity is associated with particles in the respirable range of sixes. last data from cascade iy actors indicate that about 90% of the activity 1s associ ated with particles 5 microns or less in the communities surrounding the Hevade Froving Grounds. D. The lungs are uniformly irradiated. E. The weight of the lungs is 900 grams. ¥. An individual inhales 20 cubic meters per 24 hours. [it ce a PAT em C = Wan 1A