Li CHAPTER VI, SECTION 2 SECTION 2 PROTECTIVE MEASURES Precautionary procedures were published and put into effect for all test events. These included siren signals, colored lights and flags, clearly marked points and routes for assembly and embarkation purposes, and a loud speaker system which included a count-down for each event. Every precaution was taken for each event to ensure the safety of personnel. Prior to each event, a bulletin was given bedside distribution which properly informed personnel of the time, place, and name of the event, and of precautions to be taken. During the evening before a scheduled event a loud speaker-equipped. jeep was driven through the occupied areas of Elmer and Nan. The announcer covered all essential information necessary for safe and orderly conduct during the event, including a reminder about the colored light and flag signals mounted on the water towers at these sites. An announcement was also made at the theatre just prior to the show. The operation of this system was as follows: personnel were cautioned by loud speaker to proceed to the assembly areas, where the countdown announcer issued safety instructions ap- plicable to each event. Guardscirculated through all living quarters after the H minus 30 minute signal to clear the quarters. During the 15 minutes prior to H-hourall instructions were issued over the count-down system. At the H minus 1 minute siren all personnel were instructed to put on their high-density goggles or face away from the direction of the blast. Depending on the type of event, additional instructions were issued to ensure safety of personnel and proper- ty; for instance, instructions for additional clothing for protection from thermal radiation, for sitting down to observe shot, for bracing of structures, and for locating personnel at places removed from danger of wave action and falling objects. At the ‘‘all clear” signal or post- ponement announcement, all personnel cleared SITE ELMER the areas as instructed. The prompt and enthusiastic cooperation by all personnel indicated their awareness of the necessity of strict enforcement of regulations to ensure a safe Operation. GREEN LIGHT ON — Event scheduled for Eniwetok Atoll will go as scheduled. Protective measures were taken at all sites prior to each event. These measures provided for RED LIGHT ON — Event scheduled for Eniwetok Atoll has been postponed. YELLOW LIGHT ON — Event scheduled for Bikini Atoll will go as scheduled. YELLOW LIGHT OFF — Event scheduled for Bikini Atoll has been postponed. SITE NAN GREEN LIGHT ON— Event scheduled for Bikini Atoll will go as scheduled. RED LIGHT ON — Event scheduled for Bikini Atoll has been postponed. YELLOW LIGHT ON — Event scheduled for Eniwetok Atoll will go as scheduled. YELLOW LIGHT OFF — Event scheduled for Eniwetok Atoll has been postponed. Note: The use of colored flags was coinci- dental with the system of colored lights. At H minus 45 minutes on the day an event was scheduled for early morning, a fire truck covered the occupied areas of the camp with its siren blowing to ensure that all personnel were awakened. At H minus 30 minutesall protection of not only permanentfacilities, but also semi-permanent and expendable construction necessary for support during subsequent events. Each situation presented specific re- quirements and was handled accordingly. For instance, at a camp where occupancyor re-entry was planned, the protective measures included bracing, guying, and removing broad surfaces to protect facilities from blast effects, while at camps to be abandoned the main concern was salvage and removal of property and equipment which might be used in future Operations. Significant factors which in all probability would have caused extensive damage to permanent facilities at Sites Fred, Elmer, and David were: (1) predicted overpressures resultant from YELLOWWOOD, OAK, PINE, and PINYON events, and (2) the predicted wave heights in consequence of the OAK, PINE, and PINYON events. To alleviate possible blast damage to permanent structures, a joint study was made by the Home Office Structural Engineering Section and the Home Office Blast Study Group. This study resulted in the internal and external bracing and guying of manybuildings and structures. For protection against possible wave damage, Page 447