Editing Nitrox (section)

==Terminology==
Nitrox is known by many names: Enriched&nbsp;Air&nbsp;Nitrox, Oxygen&nbsp;Enriched&nbsp;Air, Nitrox, EANx or Safe&nbsp;Air.<ref name=dan/><ref name="Elliott 1996" /> Since the word is a compound contraction or coined word and not an acronym, it should not be written in all upper case characters as "NITROX",<ref name="dan"/> but may be initially capitalized when referring to specific mixtures such as Nitrox32, which contains 68% nitrogen and 32% oxygen. When one figure is stated, it refers to the oxygen percentage, not the nitrogen percentage. The original convention, Nitrox68/32 became shortened as the first figure is redundant.{{Citation needed|date=January 2009}}

The term "nitrox" was originally used to refer to the breathing gas in a seafloor habitat where the oxygen has to be kept to a lower fraction than in air to avoid long term [[oxygen toxicity]] problems. It was later used by Dr Morgan Wells of NOAA for mixtures with an oxygen fraction higher than air, and has become a generic term for binary mixtures of nitrogen and oxygen with any oxygen fraction,<ref name="dan"/> and in the context of recreational and technical diving, now usually refers to a mixture of nitrogen and oxygen with more than 21% oxygen.<ref name=dan/> "Enriched Air Nitrox" or "EAN", and "Oxygen Enriched Air" are used to emphasize richer than air mixtures.<ref name=dan/> In "EANx", the "x" was originally the x of nitrox,<ref name=noaa/><!--alternative interpretations have been suggested--> but has come to indicate the percentage of oxygen in the mix and is replaced by a number when the percentage is known; for example, a 40% oxygen mix is called EAN40. The two most popular blends are EAN32 and EAN36, developed by NOAA for scientific diving, and also named Nitrox I and Nitrox II, respectively, or Nitrox68/32 and Nitrox64/36.<ref name=noaa/><ref name=dan/> These two mixtures were first utilized to the depth and oxygen limits for scientific diving designated by NOAA at the time.<ref name=Mastro1989 />

The term Oxygen Enriched Air (OEN) was accepted by the (American) scientific diving community, but although it is probably the most unambiguous and simply descriptive term yet proposed, it was resisted by the recreational diving community, sometimes in favour of less appropriate terminology.<ref name="dan"/>

In its early days of introduction to non-technical divers, nitrox has occasionally also been known by detractors by less complimentary terms, such as "devil gas" or "voodoo gas" (a term now sometimes used with pride).<ref name=oxyhackers />

[[American Nitrox Divers International]] (ANDI) uses the term "SafeAir", which they define as any oxygen-enriched air mixture with O<sub>2</sub> concentrations between 22% and 50% that meet their gas quality and handling specifications, and specifically claim that these mixtures are safer than normally produced breathing air for the end user not envolved to the mix production which.{{clarify|typo or grammar error garbage|date=January 2022}}<ref name="SafeAir" /> Considering the complexities and hazards of mixing, handling, analyzing, and using oxygen-enriched air, this name is considered inappropriate by those who consider that it is not inherently "safe", but merely has decompression advantages.<ref name="dan"/>

===MOD===
{{Main|Maximum operating depth}}
Maximum Operating Depth (MOD) is the maximum safe depth at which a given nitrox mixture can be used. MOD depends on the allowed partial pressure of oxygen, which is related to exposure time and the acceptable risk assumed for central nervous system oxygen toxicity. Acceptable maximum ppO<sub>2</sub> varies depending on the application:<ref name="dan" />
* 1.2 is often used in closed circuit rebreathers.
* 1.4 is recommended by several recreational training agencies for ordinary scuba diving.
* 1.5 is allowed for commercial diving in some jurisdictions.
* 1.6 is allowed for technical diving decompression stops, and is the recommended maximum according to NOAA<ref name="noaa" />
Higher values are used by commercial and military divers in special circumstances, often when the diver uses surface supplied breathing apparatus, or for treatment in a chamber, where the airway is relatively secure.