DNA 1240H-2 addition, fallout included liquid drops having a range of size up to several millimeters in diameter. The presence on the filters of many particles invisible under the microscope was indicated by the autoradiographs. It was concluded that the bomb debris mixed to some extent with the large amount of sea water and the relatively small amount of coral that were taken into the fireball.o4 In addition, al- though no gross fallout was photographed on the YAG hO, small sparselyepaced particles were photogrephed intermittently, following Shot 50 Fallout dose and dose-rate measurements were also made on the two test ships, the YAG 39 (with the washdow operating) and the YAG 40 (unprotected), which were guided (some distance apart) by remote con- trol through the fallout regions of the detonations.“ Following Shot 4, the maxinum average cumulative dose up to 5 hr on the unprotected YAG flight deck was almost 100 r. Less than 10% of that dose was recorded for a similar location on the YAG 39, with washdown in operation. The highest cumulative doses were recorded at 11 hr after Shot 5, when an average dose of almost 500 r was recorded on the YAG 40 main deck forward. Less than 10% of that dose was recorded for a similar location and exposure time on the washed YAG 39. At 2 hr after Shot 4, peak dose rates of 40 - 50 r/hr were recorded on the YAG 40, whereas dose rates on the YAG 39, with washdown in operation, were reduced to less than 10% of those on the unprotected ship. Following Shot 5, dose rate averages on the YAG 40 flight deck peaked at between 80 and 90 r/hr at about 3 hr after shot, while dose rates on the YAG 39 were again lees than 10% of those on the YAG 40. ‘The portion of the total dose due to deposited activity or to airborne activity is questionable. Castle data indicated that the transit dose was of minor significance on an unprotected ship, since about 95% of the total dose recorded on the weather deck of the unwashed YAG 40 was estimated to have been due to deposited activity. For bursts of this type, washdown appeared very effective in removing activity deposited on the YAG 39 decks, since only half the total dose accumulated at the end of fallout on the washdown-protected ship was estimated to have been due to the deposit dose. Operation Redwing: Data are available on fallout from only two of the barge shots, and from Shot Tewa, which was almost a land-surface shot, since it was on a reef where the water was only 25 ft deep. Data are also available from Shot Zuni, an ieland-surface shot. Characterization“of the fallout indicated that all the fallout collected from barge shots Flathead and Navajo consisted of slurry particles, whose inert components were water, sea salts and a small amount of insoluble solids, principally oxides of calcium and iron. The diameters of the spherical slurry droplets at time of arrival ranged from 57 to 121 microns for Flathead, and from 75 to 272 microns for Navajo. Nearly all the active fallout collected from Shot Tewa LLE OGer Y D A L I A y a r s e g rp ~~ 17-72 ee ewe