TM 10-6640-239-13 1-4     Laboratory shall be adequately ventilated.     Fire fighting equipment shall be checked periodically to assure it is properly serviced and ready for use. This is done by checking seals, tags, pressure gauges, and hoses. c. Extinguishing Fires.  Be familiar with the nature of petroleum fires; with procedures for fighting fires; and with the fire extinguishing equipment in the laboratory.  Do not use water for extinguishing oil fires because it will spread the fire.  Water is a conductor of electricity and should not be used on electrical fires. d. Handling Chemicals.  The following safety precautions shall be observed by all personnel while handling chemicals.     Store heavy and large containers of chemicals on or as near the floor as possible.     Never fill a container with material other than that indicated on the label.  Every container shall be properly labeled.     Bottles containing acids or alkalis shall not be placed on high shelves or on top of equipment.     Always wear goggles when breaking up solid chemicals which might chip, or when handling quantities of corrosive liquids such as strong acids and strong bases.     When opening new bottles of acid, always wear goggles.     When pouring a sample from a container, hold the container cap or stopper in your hand.  Never place the cap or stopper on a counter where it may come in contact with a contaminating agent.     Always wipe up any acid that spills or splashes on benches, tables, or floors.     If any chemical is spilled or splashed on the body, immediately wash the contaminated area thoroughly with water.     Keep all sample containers that are in use capped or stoppered at all times except when pouring out test portions.  Always replace the same cap or stopper on the container from which it was removed.     Never handle mercury with bare hands; never heat mercury in an open container; and never shake more than 20 millimeters of mercury in a glass container.     Never taste laboratory chemicals.  Smell a chemical only when necessary and then only by wafting a small amount of vapor with the hand toward the nose.     Dispose of all unlabeled chemicals. e. Controlling Pressure and Vacuum.  The following safety precautions shall be observed by all personnel while operating the air/vacuum systems.     Do not use faulty copper, plastic, or rubber tubing when performing operations requiring pressure or vacuum.     Glass vacuum apparatus shall be 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 properly.     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.  After venting containers, return the cap or stopper to the container from which it was removed.  The practice of venting containers of volatile liquids does not apply to those samples collected for vapor pressure tests.