Nitrox is used in Scuba diving. It is a a breathing gas consisting of air mixed with a higher percentage of oxygen than normal air. Above 40% is uncommon within recreational diving. The two most popular blends are EANx32 and EANx36 (also named Nitrox I and Nitrox II).
There are several ways of mixing Nitrox. One can put pure oxygen into a tank and then fill with air to make the wanted mix. Another way is to remove nitrogen from air with a special filter or membrane, or have it premixed industrially.
Using EANx means that the rate of nitrogen absorption into the body is reduced. This means that the length of time a diver can remain at depth without requiring decompression increases (115 minutes versus 55 minutes at 60 feet) and the risk of decompression sickness is reduced by lowering the nitrogen levels within the diver's body tissues.
Diving with Nitrox and dealing with Nitrox mixes raises a number of potentially fatal dangers due to the high partial pressure of oxygen. Tanks may explode if treated improperly.
Nitrox is not a deep-diving gas mixture.
More advanced diving gas mixtures are Normoxic and Trimix.