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A Fire Hazard in Your Neighbor’s Garage?

February 19, 2014

house fires

No, not their restored 1971 Ford Pinto sedan or their new liquefied petroleum gas-fired combination grill, roaster and deep-fat fryer.

I’m old enough to remember when Ford introduced the Pinto and gasoline was 26 cents a gallon.  During the “first” energy crisis in the 1970’s (when gas reached an astounding $1.50 a gallon, gasp!) many self-proclaimed inventors tried to find inexpensive alternative fuels.  Some of their efforts ended tragically when the inventors’ plans went wrong while experimenting with volatile fuels.

When traditional fuels become expensive, inventors go to work trying to discover the “next big thing” that will make them famous . . . and rich.  There often are risks that go along with the creativity, however.

Like many alternative energy sources, biodiesel is becoming more and more of a challenge for first responders.  Whether it’s created from algae, waste cooking oils or some other biomass, the production of biodiesel has inherent risks. The problem lays not with the “legitimate” manufacturers, but the backyard tinkerers who may think they have the solution to the world’s energy shortages.  We’ve seen similar hazards with ethanol, wood stoves and, to some extent, compressed gases.

Much of the small scale production occurs in private garages, barns and outbuildings outside the scope or awareness of local code officials.  There have been many reports of fires and explosions resulting from unregulated experiments and processing.

Finished biodiesel generally is a Class IIIB liquid (flash point > 200°F), so it is a fairly stable product (Fuel Oil No. 2, the petroleum version that we put in our cars, is blended to have a flash point between 101°F and 140°F, depending upon consumer needs and market conditions.)

The hazards to first responders occur in the production phase. Manufacturing operations have significant hazardous material issues. An alcohol and a base are required to create biodiesel.  Generally, methanol or ethanol is mixed into a solution of sodium hydroxide (the base) while being heated. This can be a significant event because of the heat of reaction, so it has to be performed at very controlled flow rates. If it is not properly mixed, an incompatible chemical reaction can cause a small deflagration.  The mixing is performed to create an intermediate chemical called sodium methoxide.

Sodium hydroxide is extremely corrosive. It can cause burning to unprotected skin and is particularly damaging to the eyes. Stirring the liquid often can produce a fine mist of liquid droplets. Severe irritation of the respiratory tract and breathlessness can occur if this mist is inhaled. Accidental swallowing can cause major damage to the throat lining and digestive system.

Methanol is a toxic and flammable chemical. It can enter the body through breathing in the vapor, direct skin contact or by accidental swallowing. It can cause nausea, dizziness and visual disturbances that can result in blindness. Swallowing small quantities could pose a significant health threat to the central nervous system and could also affect other vital organs. It is a cumulative poison and repeated exposure to relatively low concentrations could cause harm in the longer term.

Methanol has a flash point of 52°F, and when ignited burns with a clean clear flame that is almost invisible in daylight. Concentrations of greater than 25% methanol in water can be ignited. To control burning methanol, you should use a fine water spray or alcohol-resistant foam.  Always wear full protective clothing that includes breathing apparatus.

When the sodium methoxide is added to the animal or vegetable oil, the biodiesel separates into the chemical family called an ester. The ester is formed by the sodium methoxide. This ester is the biodiesel. Generally the process also will produce a fair amount of glycerine, also a Class IIIB liquid.

Accidents in the biodiesel industry have included: methanol spillage igniting and fire spreading to storage tanks, people being burned by sulphuric acid due to poor training/supervision/suitability, small processors exploding due to accidentally switching on electric immersion heaters, pipework bursting due to using incompatible materials, adding methanol to hot oil and small fires escalating to large fires due to using plastic reactor vessels.

Have you seen biodiesel production operations in your first-due district?  Have you noticed anyone with a surplus of metal or plastic cans and containers laying about their yard?  Have you noticed the smell of fermenting grasses or vegetation?  Any one of these could be signs of biodiesel experimentation or production.  If you respond to one of these operations, conduct a good size up and fully assess the risks before attacking a fire.

For sources and additional information, go to:

Check out this video explanation of the biodiesel production process and associated risks.

For a comprehensive primer on biodiesel check out the Virginia Department of Environmental Quality.


Article by: Robert Neale

 Rob is the Deputy Superintendent for Curriculum and Instruction at the National Fire Academy, a division of the US Fire Administration. In this role he manages the development and delivery of National Fire Academy curriculum including the Coffee Break Training Fire Protection Series on


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