Dear Professional Driver,

Last month there were 2 incidents, within one week, involving liquid petroleum tanks exploding; seriously injuring workers in the process of making tank repairs. In both cases, the tanks were emptied of product prior to “hot work” (welding) being performed. People need to realize that even though a liquid petroleum tank may be empty of product, unless purged; vapors remain. These vapors are far more volatile than the product itself. Drivers, mechanics and consumers have a difficult time understanding the relationship between the liquid petroleum product, its Flash Point and the vapors released.

The definition of Flash Point is the lowest temperature a liquid petroleum product can vaporize, releasing an ignitable mixture into the atmosphere. When these vapors are exposed to an ignition source, serious consequences will occur (i.e. explosion and fire). Here are Flash Points for liquid petroleum products J & S Transport handles:

Gasoline = – 45 Degrees Fahrenheit (yes, that’s minus 45)
Diesel = + 144 Degrees Fahrenheit
Kerosene = + 110 Degrees Fahrenheit

People need to keep in mind that vapors burn and not the petroleum liquid itself. As long as the product continues to release vapor, this volatile mixture will continue to burn. I like to use a can of “Sterno” as an example to prove this point. Next time you use a chaffing dish heated with “Sterno”, remove the can’s lid and place a match near the opening. What happens? The vapors released by the gel quickly ignite providing the flame heating the dish. Once you put the lid back on the can, the flame is extinquished. No longer is the volatile mixture of vapors and oxygen exposed to an ignition source. This is the same principle used when emergency responders arrive at an accident scene involving a liquid petroleum fire. They immediately apply a thick foam blanket to cover the released liquid to smother the vapors while cutting off the oxygen feeding the flames. Also, have you watched an action of war movie whereas a ship explodes, sinks, with survivors surrounded by flames on the water? It would be safe to assume the flames are the result of the ship’s fuel having been released from ruptured fuel tanks. Keep in mind, it’s not the actual fuel floating on top of the water burning, but the vapors released from that fuel having been exposed to an ignition source.

This is why 49CFR Part 172.514(b) of the Hazardous Materials Regulations requires:

“Each bulk packaging that is required to be placarded when it contains a hazardous material, must remain placarded when it is emptied, unless it… is sufficiently cleaned of residue and purged of vapors to remove any potential hazard.”

Be Safe!!

Steve