consumption habits that were dissimilar. However, the latest determination of internal dose for the Marshallese (Reference 19) considers ingestion to be the dominant pathway and arrives at significantly greater thyroid doses than previously calculated. Dr. Harris considers that ingestion through food or drinking water also contributed to the internal dose of the servicemen on Rongerik (Reference 9). Scoping calculations suggest that both inhalation and ingestion pathways could have contributed significantly to internal dose at Rongerik, but that inhalation could not have dominated. As derived in Reference 20, the inhaled activity (curies) from full exposure to descending fallout is roughly 107? x peak gamma intensity (R/hr) x time of fallout after detonation (hr). The values of these parameters obtained in Sections 2 and 3 imply an inhaled activity on the order of 1 mCi. Ingestion could have resulted in virtually all of the activity intake, if, for example, food on a plate exposed to 15 minutes of significant fallout deposition were entirely ingested. At the time of, the peak intensity, the areal concentration of activity exceeded 1 Ci/m? (Refer-— ence 11). With a plate size of 0.1 m2 and exposure for 5 percent of the estimated duration of significant fallout, an intake of 5 mCi is implied. Later pathways are less likely to have contributed significantly to internal dose. Fallout, which had accumulated to a noticeable depth, would have been brushed or washed off of objects pertinent to ingestibles; at lower levels of contamination, an unrealistically large surface area would have to be involved for ingestion at the mCi level. Inhalation during the following day of contaminants resuspended by wind or _ personal agitation would have been minor. The particle-size characteristics of the airborne fallout material are adequately known. Based on considerations of particle fall rate, Bravo cloud height, and time after detonation, it is estimated that the deposited fallout particles were in the size range of 55 to 120 um diameter. Analysis of soil samples on Rongerik indicated that most of the radioactivity in soil was associated with particles in the size range of 60 to 200 um diameter (Reference 13). In the context of aerosols, the deposited material consisted of large particles (greater than 10 um in diameter). For dosimetric purposes, differentiation among large particle sizes is unnecessary, as shown below. 20