UNCLASSIFIED * t ce Ww caission te wcrous nuclear radiation can be separated into tio time periods. The primary radiection which occurs at the tiow of the flash is composed of grama rays and nvutrons. This flash exposure is very short.” Casualtios may result from this primary radiation if the exposure occurs withia 2500 yards of sero. he. Tho neutrons may cruate a secondary or residual hasard by including radioactivity in certain ulements within the range of approximately 1000 yrrus, As a result, objects in the arwa near the point of detonation aay becom radioactinw and herardous to personnyl. Siatlorly, the salt water nearby aay Present s weterbdome hasard. fe Another and usually sore important source of residual radioactivity is the radioactive Mission products. Theso will bo deposited on the ground hear the point of detonation or they will be carried aloft in the doaab cloud. Most of these fission products in the cloud arc carried to 20,0 to 50,000 feet, become greatly diluted, and are dispersed domwind. particulate matter falls out. cradually the This “fall-out” of radiosctin material may sut up localised danger arvas. It appwars unlikely that them would be any significant hazard from this airborne contamination at s distance of mor than 100 nautleal miles fram tho center. 2. FRoTectiow a. fgainst the primary uffects, distance will provida the best protcetion. b. For thy protection of thy vyes against excessive light, special goggles are required for personnel within fiftcen (15) nautical milus of the flash if looking at tt. At thie distame the light may be of such intensity as to te painful to the unprotected cye, producing an immediate temporary blinding, lasting for a half hour or scrv. It must be rumatened that the sunlight will be much luss than at Bikini, and therefore the pupil of the eyo will be dilatod, necessitating greater protection for the eyes. The heat of the flash ts felt on the bare skin out to at least fifteen (15) miles. Ce Against the secondary radioactivity hasards froa radioactive “sston products, induced radioactivity, and unfisstioned residus, detection and avoidance prowide the best protection. This is the basis of the Radiological -- .