Many believe that nitrox diving is a recently adopted technique for recreational divers. In all reality, nitrox has been known about for many years. In the late 19th century the first rebreather systems used gas that was largely "nitrox".

Military divers have used nitrox for their semi-closed circuit rebreathers throughout the 20th century. In fact, nitrox was considered so important to the British military during WWII that its existence was considered a military secret!

1950's

In the 1950s, one of the popular scuba training books, The Science of Skin and Scuba, indicated that by increasing the oxygen of the breathing mix, you would reduce the effects of nitrogen. Obviously, it went on to explain how difficult it would be to produce and analyze, so therefore was not practical.

Later, cave divers began to employ oxygen enriched mixes and then, of course, the NOAA program was made public. In the NOAA diving manual a complete description of nitrox diving techniques and considerations was published. By the mid 1980s the technology had improved as well as the sophistication of the divers. Currently both the production and analysis of nitrox diving gases is done with ease.

1980's

Dr. Morgan Wells and Dick Rutowski of NOAA were instrumental in helping bring acceptable nitrox diving procedures to recreational divers which resulted in the formation of the early "technical" agencies such as IAND (later IANTD), ANDI and TDI.  PSA was in existence for about 20 years prior to the start of the other technical agencices.

During the 1980s there was considerable resistance to the acceptance of breathing anything other than air. PSA and the other technical agencies continued to support the safety and exploit the increased bottom time advantages of nitrox and finally all mainstream recreational agencies have adopted some form of nitrox course.

1990's

In 1995, the Professional Association of Diving Instructors (PADI) announced full educational support for nitrox. While other main line scuba organizations had announced their support of nitrox earlier, it was PADI's endorsement that put nitrox over the top as a standard sport diving "option."

Despite its long history of acceptable use and advantages, there are still some out there who continue to shun or bad-mouth nitrox. There are many misinformed divers as well, so if you ever have any questions, do not hesitate to call on your PSA Nitrox instructor for proper guidance.