TM 10-6640-215-13 1-8.  SAFETY, CARE, AND HANDLING - continued. Make sure that glass vacuum apparatus is properly shielded when it is in use. Always wear goggles when opening air valves that are close to the face. Make sure that chemical containers having vent caps are inspected, and that containers which do not have vent caps are vented periodically. Keep containers of volatile liquids as cool as possible.  Exercise caution in releasing any pressure which may have formed in the container; always release the pressure gradually.  Remove caps or stoppers periodically to vent the vapor.    The  practice  of  venting  containers  of  volatile  liquids  does  not  apply  to  those  samples  collected  for  vapor pressure tests. Vent separator funnels frequently when shaking volatile liquids.  Always wrap the funnel with a rag when shaking an extremely volatile liquid. Store propane cylinders in the propane stowage locker, away from heat or ignition sources. f. Controlling Fumes.  The following safety precautions are presented to aid operators of the Petroleum Laboratory in controlling toxic fumes. Make certain the laboratory is properly ventilated at all times. Perform all gas alarm system tests and calibrations as specified to ensure proper operation of system. If any material is spilled which gives off toxic fumes, all personnel should leave the area immediately and return only after the area has been adequately purged. g. Electrical Safety.  The following electrical safety precautions apply to all operators and maintenance personnel for the Petroleum Laboratory. Equipment producing a tingle sensation will be reported promptly for repair. Keep the use of extension cords to a minimum and the cords as short as possible.  Be sure insulation and wire size are adequate for the voltage and current to be carried. Work   on   electrical   devices   should   be   done   after   the   power   has   been   disconnected   or   shut   off,   and   suitable precautions taken to keep the power off during the work. Never use metallic pencils or rulers, or wear rings or watches when working on electrical equipment. Avoid using or storing flammable liquids near electrical equipment. 1-5