Gasoline is a material with density and vapor pressure characteristics that let it travel a fair distance from the source, and mix readily with air. If the concentration in air is above 1.4%, or below 7.6%, it is explosivly flammable. 1 gallon of spilled gasoline can produce an explosive mix equivalent to over 500 gallons volume (Think of 10 of those 55 gallon oil drums). More probable than an explosion, however, is a very rapid and hot fire.
All the scary stuff said, chances are pretty low that it is going to explode or ignite from your engine. More likely to go off from the engine of the guy waiting in line behind you to use the pump - his engine is usually closer to your gas tank than your engine, and he/she usually doesn't shut off while waiting! However, as Clint Eastwood said, "Do you feel lucky?". You are betting that random chance will not create an explosive mix of air and gasoline, and will not provide a spark. Extremely unlikely events for random chance to reproduce?
Our emergency room once had a patient who was cleaning parts in a pan containing about a pint of gasoline. It was a nice, hot, dry day. He dropped his wrench onto the concrete floor while he was putting a part into the pan. WHOOSH! No more eyebrows or lashes, and an instant blistered and bright red face! Luckily he was not inhaling at the time the mix went off, or ditto conditions to his throat and lungs!
Extremely unlikely does NOT mean the same thing as impossible. Always cut the cards!
87 300E, 65k miles
[This message has been edited by JCE (edited 11-15-2000).]