If handled properly, natural gas is as safe as gasoline. Compared with gasoline, it requires a higher concentration of natural gas in air and a hotter ignition source to start combustion.
Because natural gas is stored under pressure, natural gas fuel systems are robust and hold up well in accidents. This has proven to be a safety advantage over gasoline vehicles. Federal, provincial and territorial regulations spell out the safe design, manufacture, testing and installation of natural gas vehicles.
There are few differences between natural gas and gasoline vehicles. There can be a slight drop in the maximum horsepower of converted engines under a wide-open throttle, because natural gas is less dense than gasoline and displaces some of the air that was destined for the engine. But factory-built natural gas vehicles are designed to provide similar horsepower to the gasoline versions of the same vehicle.
In colder weather, allow a warm-up period similar to that for gasoline vehicles to ensure proper engine lubrication. If you would normally use a block heater for your gasoline vehicle, use one for your natural gas vehicle.