If it concerns folks that much, they can just buy a NASCAR-specification fuel cell, and install it according to round track race car construction rules. The tank, and the installation cost will run somewhere just south of $1K, but you can forget about fire in anything short of a 200 MPH multiple rollover situation.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!