from other types of soil, not predominantly coral, might vary considerably in chemical and physical makeup, 12.4 color and particle size. Radioactive Hazards Associated with Fallout Radioactive fallout may result in 3 types of exposure: exposure from gamma radiation; (1) whole body (2) radiation of the skin from deposition of fallout material thereon; and (3) the internal absorption of radioactive materials. Figure 3 is a rough diagramatic sketch showing the relatively uniform distribution of fallout on the ground, houses, trees and Marshallese personnel. The penetrating gamma radiation, which is represented by the wavy shaded areas, penetrates many yards in air before it is attenuated appreciably. There was, of course, no neutron radiation associated with the fallout. Beta radiation as represented by the stippling in the figure was completely attenuated in several feet of air. Estimates of the beta to gamma retio vary widely up to 150/1 depending upon the exposure conditions. Alpha emitters were not present in the fallout to any great extent. Even if significant amounts had been, due to their weak penetrating ability, they would not likely add significantly to the skin damage, but might present a hazard from the point of view of internal absorption. Internal absorption of fallout occurs to some extent from inhalation but to a greater extent from ingestion of contaminated food and water. 12.5 Dose Estimations in the Marshallese 12.5.1 Whole body dose. The gamma radiation dose which resulted in a penetrating whole body exposure of the Marshallese was calculated from field instrument readings taken shortly after the accident, spectrometric and