Do you turn off your engine at the gas station?

http://epa.ohio.gov/Portals/41/p2/HC2web.pdf

"The flash point of a material is a good indicator of how likely it is to catch on fire if there is an ignition source nearby. At the flash point, the material will have just enough vapor available to support a flame. The lower the flash point, the more of a fire danger the material is

Gasoline is the most dangerous with a flash point of about - 45o F. Kerosene is the next most dangerous with a flash point of about 100o F. The flash point for diesel oil and home heating oil is about the same, 125o F."

Hence, there is a difference in fueling risk between gasoline and diesel.