Detailed   information   relative   to   the   storage, handling, and use of various types of compressed gases are contained in the Naval Ships’ Technical Manual,   chapters   670   and   9230.   Information pertinent  to  especially  hazardous  gases  commonly used   by   ships   is   provided   in   the   following subparagraphs. ACETYLENE.—   Acetylene  is  inherently unstable  and  may  explode  when  subjected  to  heat or  shock,  or  upon  contact  with  chlorine  or  cer- tain metals such as copper, silver, and mercury. Therefore,  acetylene  must  be  stored  separately from  oxygen  or  any  other  materials  with  which it  forms  an  explosive  compound;  the  gas  must never be allowed to escape into an enclosed area; and the cylinders must be protected from flames, sparks, lightning, and static electricity. Testing for suspected  leaks  should  be  done  with  soapy  water. In  moderate  concentrations,  acetylene  may  act as an intoxicant. In higher concentrations, it will cause unconsciousness and, ultimately, asphyxia- tion. Some grades of acetylene also contain many impurities.  Therefore,  breathing  of  acetylene  in any concentration for any length of time must be avoided. Acetylene in cylinders is dissolved in acetone which has a tendency to flow into the valve if the cylinders are stored horizontally. For this reason, acetylene  must  be  stored  and  used  only  in  an upright position, valve end up. When it is known or suspected that acetylene cylinders have been stored on their sides, they must not be used until they have been in a vertical position for at least 2  hours. OXYGEN AND CHLORINE.—  Oxygen and chlorine  are  oxidizing  gases  that  strongly  support combustion  because  they  can  burn  without  air. (Chlorine is also poisonous.) Oxygen and chlorine cylinders must be stored on the weather deck, or in  a  separate  watertight  storeroom  that  has  at  least one compartment between it and any space that is  used  for  the  storage  of  combustibles  such  as flammable  liquids  or  gases,  ammunition,  paint, gasoline,  and  oil. NONFLAMMABLE  GASES.—  Helium,  ni- trogen,  carbon  dioxide,  and  argon  are  non- flammable   gases   that   because   of   their   inert characteristics may be stored with flammable or oxidizing  gases.  However,  since  these  nonflam- mable gases will not support respiration (a suffi- cient  concentration  in  a  closed  space  will  cause asphyxiation),  they  must  be  stored  on  the  weather deck  or  in  other  well-ventilated  spaces. AEROSOL PRODUCTS.— Aerosol products are  liquids,  solutions,  or  powders  suspended  in a  gas  propellant  and  contained  in  dispensers equipped  with  release  valves.  Containers  of aerosol  are  used  for  the  disposal  of  paints, enamels,   lacquers,   insecticides,   silicones,   rust preventives,  and  so  forth.  The  aerosol  propellants may be low boiling halogenated hydrocarbons or other hydrocarbons such as liquified propane or isobutane. Aerosol cylinders will burst if exposed to heat sources in excess of 120°F and are prone to  leakage  if  subjected  to  impact.  Aerosol propellants   are   extremely   flammable   and,   in sufficient   concentration,   can   be   anesthetic   or asphyxiating. Aerosol products, therefore, should be stored in the flammable liquids storeroom, or in  cabinets  away  from  oxidizing  materials;  and mechanical   ventilation   should   be   used,   when necessary,  to  remove  accumulated  vapors. Flammable or Combustible Material Flammable  liquids  have  a  flash  point  of  100°F or  below;  combustible  liquids,  greases,  and  pastes have  a  flash  point  of  200°F  or  below.  Items that  are  flammable  or  combustible  include  the following: Gasoline,   oils,   kerosene,   and   other petroleum  products Chemicals Stencil  paints,  marking  inks,  and  printer’s ink Solvents,  thinners,  primers,  compounds, varnishes,  and  lacquers Alcohol,  acetone,  ether,  and  naphtha Greases and pastes Except  for  drummed  petroleum  products,  which may be stored in racks on the weather deck as per the Naval Ships’ Technical Manual, chapter 670, flammable liquids and other flammable or com- bustible material will be stored in the flammable liquids   storeroom. Acid Liquid acid, unless classified as safe material in the Naval  Ships’  Technical  Manual,  chapter 670, should be stored in an acid locker. If an acid 7-4