Breathing Gas Safety: You are Also Responsible for the Quality of your own Breathing Gas

You cannot smell, taste, feel or see breathing gas: so how do you know what it is and whether it is safe to breathe? Cylinder filling operators carry a primary responsibility in this regard. However, it is the diver who is exposed to what they expect to be in the cylinder. There are some fundamental principles to know and understand if you want to be more assured of your own safety.