Protection a. Against the primary radiological effects, distance will provide Protection. b. Against the secondary radioactivity hazards from radioactive fisSion products, induced radioactivity and unfissioned residue, detection and avoidance provide the best protection. Suitable instruments indicate both the presence and intensity of radioactivity at a given Place. Area reconnaissance, the maintenance of contamination situation maps, the posting of areas of hazard and minimizing the spread of contaminated material into uncontaminated areas constitute the active measures for reducing the radiological hazard. ¢. Personnel within an operational radius of ground zero who are to be facing in the direction of the flash will be required to wear special goggles to within the face, with After ten phenomena. protect their eyes against excessive light. Personnel above operational radius who are not provided goggles will eyes closed, in the opposite direction from the flash. (10) seconds, such personnel may turn around and observe the Anticipated Hazard Areas a. Immediately under the bomb burst there will be an area of intense radioactivity extending downwind and, to some extent, crosswind and upwind with gradually decreasing intensity. b. Extending downwind (and to some extent, crosswind and upwind), an airborne radioactive hazard will exist. Its characteristics will depend on the meteorological influences such as wind speed and direction at various altitudes up to the maximum height reached by the cloud. c. Contaminated water in the lagoon adjacent to the shot site may be of consequence and will be analyzed by the radiological safety unit of TG 7.1 immediately after shot time and at other intervals. d. Unless care is exercised, individuals or objects entering contaminated areas may transfer radioactivity to clean areas. e. By means of instruments such as Geiger-Mueller counters and ion chambers it is possible to detect the area of contamination and to Measure the intensity of the radioactivity. Radiation intensity will normally be measured and reported in roentgens per hour. Besides those instruments, dosimeters and film hadges will be used as indicators of the accumulated exposure to radioactivity. Only personnel involved in work near, or in, radioactive areas will wear film badges to provide a permanent record of exposure, except that film badges will be issued to ten (10) percent of ship crews to aid in estimated crew dosage in the event of heavy fall-out. £. The intensity of the radioactive hazard tends to decrease with time due to decay of radioactive materials and dispersion and dilution, de- pending upon climatic conditions. As an approximation, the intensity 463