doors. Heavy concentrations in closely confined spaces, however, are dangerous and may be lethal because they reduce the amount of oxygen in the air. Anything more than a brief exposure to the gases of combustion, or to screening smokes, should be avoided or should be protected  against  through  the  use  of  an  appropriate breathing  apparatus. ORDNANCE HANDLING SAFETY LEARNING OBJECTIVES: Recognize safety precautions,   practices,   and   principles applicable for the handling of ordnance. List general ammunition safety precautions. List and define standard commands for gun crews. The  utmost  care  and  prudence  must  be  exercised  in supervising   the   handling,   inspecting,   preparing, assembling, and transporting of all types of ammunition. People tend to become careless and indifferent when continually engaged in work with explosives and, as long as nothing occurs, are inclined to drift gradually into neglecting the necessary precautions. Nothing but constant vigilance on the part of the all concerned will ensure  the  steadfast  observance  of  the  rules  and regulations  that  experience  has  taught  are  necessary. Safety is everyone's responsibility. Awareness of danger, knowledge of how danger can be avoided, and constant vigilance are the three basic requirements to prevent accidents when working with explosives. If a thorough understanding of the basic ideas behind the precautions  is  developed,  unsafe  conditions  can  be recognized and corrected and further suitable action taken  instinctively  when  the  unexpected  occurs.  Safety precautions pertaining to the handling of and working with explosives may be found in OP 4, Ammunition Afloat; OP 1014, Ordnance Safety Precautions, Their Origin and Necessity; and OP 3347, United States Ordnance  Safety  Precautions. Safety  precautions,  rules,  and  regulations  for handling explosives should be made the subject of frequent  review,  and  the  necessity  for  strict  compliance with these precautions should be firmly fixed in the minds  and  habits  of  all  hands  involved  in  handling explosives so that they will react in an emergency to the instruction  previously  received. Note that in the early stages of the use of explosives, experience was gamed at a great price–not only in dollars, but in human lives. No relaxation should be tolerated, since this tends to create the impression that the rules are arbitrary. All personnel assigned to handle ammunition or gunnery   equipment   should   receive   a   thorough indoctrination from a qualified chief petty officer or petty  officer  regarding  the  general  safety  precautions and procedures to be followed in the course of their duties. This indoctrination is MANDATORY before ANY   weapons-handling/firing   evolution. Periodic drills should be conducted to provide realistic training and to identify and/or eliminate any unsafe    practices.   Inexperienced   personnel   will constantly be under the direct supervision of skilled and experienced  personnel  until  adequate  experience  is acquired. Because  of  the  nature  of  gunnery  and  ammunition, safety precautions should be of extreme importance to every Seaman. Compliance with all safety procedures will  ensure  a  safe  ammunition  transfer. The   following   general   safety   precautions concerning gunnery and ammunition should be of extreme  importance  to  every  Seaman: Ammunition should ALWAYS be handled carefully and ONLY when necessary. The proper way to handle ammunition is to hold the base  of  the  projectile  downward  with  one  hand covering the base, while supporting the top of the round up at a 45° angle and cradling the top, like a baby, in the elbow. Smoking is prohibited in magazines and any area containing explosives or ammunition, as well as in the vicinity of handling or loading operations involving  ammunition. Naked  lights,  matches,  lighters  or  other  spark-, flame-, or heat-producing devices should NEVER be taken or stowed near magazines or any other area where  explosives  are  present. Unauthorized  personnel  should  not  be  permitted  in magazines or in the vicinity of handling operations involving  explosives  or  ammunition. Personnel assigned to gunnery stations during general quarters should ALWAYS know the type of ammunition  being  handled. Ammunition  handlers  should  wear  appropriate clothing and safety shoes. Ammunition handlers should never wear keys, gloves, rings, watches, or headgear  when  handling  ammunition.  Belt  buckles should be turned inside or be removed to avoid the possibility of striking a primer on a projectile. 6-14