Why are there places on the TTC where Natural Gas buses are not allowed?
The initial answer we gave you was wrong. We would like to thank Keith Littlewood for setting us straight. In his words: “Actually, Compressed Natural Gas is lighter than air. A Natural Gas leak tends to vent upwards and would become trapped on the ceiling of an enclosed structure. Propane, on the other hand, is a heavier than air gas that would collect at ground level. I recall accidents a few years ago with Toronto taxicabs where a propane leak resulted in an excessive concentration of fuel collecting inside the vehcile that ignited when the ignition switch was turned on (not when the engine started!). The provincial Fuel Safety Branch has recognised this fact and for many years has prohibited the indoor storage of propane fueled vehicles, while permitting indoor storage of natural gas vehicles. The Hamilton Street Railway (where I was employed during the test program and systemwide introduction of natural gas buses) and London Transit operate natural gas buses that are stored indoor
