Manual shutoffs may also be present to shut off the flow of gas.As with conventional vehicles, a hand line with personnel in full firefighting PPE should be in place during extrications.Natural gas is lighter than air and will rise upon its release.Its flammable range is 5 to 15 percent in air and its ignition temperature is 1,100 degrees Fahrenheit.Natural gas is stored on a vehicle in one of two ways, either compressed or liquefied.