If you have been diving for a long time, you may think diving with Nitrox is new. In a way it is, and in other ways it is not. In 1912, Germans were diving using mixtures of 45% oxygen and 55% nitrogen to a maximum depth of 100 feet (30 meters). Later, they developed equipment designed to use a mixture of 30% oxygen and 70% nitrogen down to 200 feet (60 meters).
Little was done with these gas mixtures, over the years, in favor of using air and open circuit scuba because of ease and availability. However, hardhat divers in the 1950’s began using various Nitrox blends to extend their working safety.
In the 1970’s, using data developed by commercial divers, as well as other research, the United States National Oceanographic and Atmospheric Administration (NOAA), under the direction of Morgan Wells and Dick Rutkowski, introduced Nitrox to divers working with the agency. NOAA allowed open circuit research divers to use mixtures NOAA termed NOAA I. These contained 32% oxygen, and later NOAA II, containing 36% oxygen.
In 1985, the International Association of Nitrox and Technical Divers, IANTD, taught it’s first Nitrox course in the Bahamas. It would be ten years before the other training agencies began teaching Nitrox diving.