Here they use biofuel gel (methanol-based); had a recent fatal fire involving the stuff. Problem is that it burns with a faint blue colour that is often not visible in daylight. Attempts to refuel from a gallon container (in my case; half-full) caused the vapour therefrom to be ignited, flash back and blow the remainder of the gel contents onto the victim. Flashpoint of Methanol is unfortunately within room temperature, so this blowout is quite violent.