Propane gas tanks were used a few years ago by a couple of terrorists trying to blow up Glasgow airport. This pair of bright sparks drove a Cherokee right into the terminal building and attempted to set the tanks and themselves alight. Considering one was a doctor and the other an engineer, (I think) they didn't have much of a criminal masterplan - and got punched out very rapidly by the locals - Glasgow being being pretty notorious as a tough violent place.
One died of his burns the other is now doing 30 years. They've probably moved the Cherokee by now and maybe even tidied up a bit at the airport, but I'm pretty certain scots civilisation hasn't taken a great hit.
http://en.wikipedia.org/wiki/2007_Gl...Airport_attack