CNG is pretty much safer than any other fuels but the only drawback it holds is that the tank installed to store the fuel takes a lot of space, for example the trunk of the car may be used up by the tank and you cannot use that space for other purpose. and coming to its advantages, the fuel is cheaper, the vehicle gets less repairing work during its life, the engine oil gets increased life, and the emissions are less compared to that of diesel or petrol.