remaining,there for 24-48 hours; and that at abc ut 190 miles the radiation would have been fatal to &bout 5 to 10 percent of the people poolat, Ayprrwed ' would have been Thus about 7,000 square miles of territo so severely contaminated that survival would dep nd upon the most Prompt protective measures. Beyond a point abouk 220 miles distant it ig unlikely that any radiation deaths would have cecurred, angerous fallout Fortunately, adequate protection against is usually found in and around American cities, nd if proper precautions are taken to avoid exposure, as indidated below, casualties from radiation can be reduced to very|small numbers. IV. Summary Conclusions for Civil Defense A, Early protective action is vitally impdrtant since the dosage a person completely exposed might receive fin the first few hours after fallout has started will exceed that khich the same person would receive over the rest of a@ week spe in the same location. B, In an area surrounding ground zero and fin a much larger area in the direction of the effective wind, radiktion intensities may be so high that most civil defense activities§{ will have to be postponed or conducted with great caution. Dange determined by radiological monitoring techniques areas must be nd civil defense decisions must be made with serious regard to the radiological situation, Cc. The threat to many rural areas, especia Lly to those which are on the prevalent down-wind side (usuall r eastward) of large target cities, necessitates extensive civil defense preparetions. D. Civil Defense organizations must vastly increase the capability of radiological defense services, part: cularly monitoring, DOE ARCHIVES 10