What is Nitrox? Enriched Air Nitrox, Oxygen Enriched Air, Nitrox, EANx, Safe Air Breathing in the Deep The common gasses used in diving include compressed air and Nitrox. Nitrox is a mixture of gas composed of nitrogen and oxygen. Nitrox also contains normal air, which is 78% nitrogen, 21% oxygen and 1% of other gasses, primarily argon. Scuba diving is diving with a self-contained underwater breathing apparatus, that is completely independent of surface supply. Providing the diver with the advantages