text: In 1994, John Lamb and Vandagraph launched the first oxygen analyser built specifically for Nitrox and mixed-gas divers, at the Birmingham Dive Show.
  In 1994, BSAC reversed its policy on Nitrox and announced BSAC nitrox training to start in 1995.
  In 1996, the Professional Association of Diving Instructors (PADI) announced full educational support for nitrox. While other mainline scuba organizations had announced their support of nitrox earlier, it was PADI's endorsement that established nitrox as a standard recreational diving option.
  In 1997, ProTec started with Nitrox 1 (recreational) and Nitrox 2 (technical). A German ProTec Nitrox manual (ref to the 6th edition) has been published.
  In 1999, a survey by R.W. Hamilton showed that over hundreds of thousands of nitrox dives, the DCS record is good. Nitrox had become popular with recreational divers, but not used much by commercial divers who tend to use surface supplied breathing apparatus. The OSHA accepted a petition for a variance from the commercial diving regulations for recreational scuba instructors.
  The 2001 edition of the NOAA Diving Manual included a chapter intended for Nitrox training.
  In nature
  At times in the geological past, the Earth's atmosphere contained much more than 20% oxygen: e.g. up to 35% in the Upper Carboniferous period. This let animals absorb oxygen more easily and influenced their evolutionary patterns.