Cold Weather Hazards Of Propane Fueled Vehicles Propane is a gas that is turned into a liquid when stored in pressurized cylinders. You should be aware that as the temperature of the fuel tank rises, the liquid fuel expands which increases pressure inside the tank. In cold weather, this could result in a fire or explosion if a propane-powered vehicle with more than 80% liquid fuel in the fuel tank is brought into a heated building from outside. The increased air temperature in the shop causes increased pressure inside the fuel tank. This will open the safety relief valve if the...