Flammable Liquids: General Information

Flammable Liquids: General Information

A flammable liquid is a combustible substance that catches fire and burns easily.  Flammable liquids burn with intensity and few materials can generate as many British Thermal Units (BTUs) per pound as flammable liquids.  This accounts for the rapid heat buildup and how fast the fine spreads.

Gasoline is the most common flammable liquid manufactured and used.  Because virtually everyone uses gasoline it is often assumed that everyone is familiar with its dangerous properties.  However, as familiarity breeds contempt (or at least carelessness), it may be a good idea to review this highly hazardous material.  Here are some brief but important items to remember when dealing with gasoline.

  1. It is extremely import that you realize that the liquid itself does not burn. It is the vapor that the liquid gives off that burns.
  2. Vapors usually cannot be seen, but frequently travel long distances to a source of ignition. Thus the gasoline can be located a great distance from an actual ignition source.
  3. Gasoline gives off enough vapors to flash when exposed to an external ignition source at temperatures as low as -45° F (4 C) so imagine how much vapor is given off at 70°-90° F!
  4. Gasoline vapors are heavier than air. Vapors will settle to the ground and flow similar to a liquid.  This is why gasoline vapors tend to find their way into drains, sewer lines, basements and other low spots.
  5. Gasoline must be mixed with air before it can burn. It does not take much gasoline to make an ignitable mixture.  If the gas-to-air mixture contains as little as 1.4% gasoline by volume, it can be ignited with explosive force.
  6. It is said that the potential energy in a one-gallon can of gasoline is equal to numerous sticks of dynamite.
  7. A gasoline/air mixture can be ignited by a hot surface, e.g., a smoldering object such as a cigarette, an open flame, or even a static spark. Other ignition sources include open flames, electrical switches, open motors, static electricity, heat guns, welding or cutting, and radiant heat.


  1. Practice good hygiene after handling gasoline. Thoroughly wash hands and any other areas that may have come in contact with gasoline.
  2. Avoid prolonged inhalation of vapors as gasoline because it contains benzene, a known carcinogen.
  3. What can you do to avoid a gasoline disaster? The following tips are good advice when handling or using gasoline.
  • Never use gasoline for anything other than its intended purpose, as a fuel.
  • Never use it as a cleaning solvent!
  • Store gasoline in UL-approved safety containers.
  • Never smoke when anywhere near gasoline.
  • Shut off all equipment before refueling and allow it to cool off first.
  • Inspect all fuel hoses, pipes and pumps frequently.  Fix leaks now!
  • Never fill containers while they are sitting in the bed of a pickup.  Place the containers on the ground, and then fill.
  • When fueling a vehicle, stay near the nozzle. Don’t get back in the vehicle while the nozzle is fueling.  If you get into the vehicle for some reason, upon exiting the vehicle, be sure to touch the vehicle body someplace away from the nozzle in order to dispel any static electricity that may have been generated while getting in and out of the vehicle.
  • Follow hot work procedures.
  • Should a fire start at the opening of a gas tank while fueling a vehicle, do not pull the fill hose from the tank.  It will draw vapors out and can cause an explosion.  Get away and shut down the fuel pump.

Remember!!!    Gasoline was chosen as a fuel for the same reasons that make it so dangerous.  It is easily vaporized, easy to ignite and explodes powerfully when ignited. 

Never let yourself become complacent around this volatile liquid that we use everyday.