It should be noted that particles collected in close-in early fallout from a nuclear detonation, such as those during atmospheric nuclear testing, contain multiple radionuclides including small amounts of plutonium. Fallout particles from near surface detonations tend to be of larger size (10 to > 100 microns) than particles from airbursts (1 to 3 microns). Most of the tests at Bikini were at or near surface bursts. Fallout particles from different portions of the cloud from a surface detonation contain different ratios of radionuclides due to fractionation. For example, samples collected from a dust column within a few minutes after detonation are depleted with respect to volatile isotopes as well. as isotopes having volatile or gaseous precursors. Samples collected from clouds at 70 to 80 kilometers from the detonation are enriched by isotopes having gaseous precursors. Dose to Lung Received From Pu-239 Contaminated Areas. It is difficult but not impossible to predict lung doses resulting from continuous occupancy of plutonium contaminated areas. Plutonium at Bikini is most likely to be in the oxide form and relatively insoluble. If values for resuspension (including reduction with time), air attentuation and particle size obtained from field tests are used along with para- sae MMB (PO