Special user friendly decompression tables for these EANx mixtures are available in a waterproof format. EANx was first used in 1912 and has been used extensively for over thirty years by commercial organizations and the military. It has also been used in the medical field as a therapy gas. Advanced level divers have been taking advantage of EANx for cave diving, wreck diving, marine harvest and many other diving applications. More recently, EANx has been recognized by national scuba diving certification agencies as an alternate breathing gas for recreational diving.
Many divers mistakenly believe EANx is used only on deep dives.
Actually, the ideal range of EANx is between 40 feet and 130 feet, the standard recreational depths. As a certified air diver, you were taught how to monitor your nitrogen intake by utilizing a set of dive tables. The deeper the depth, the shorter the amount of allowable no-decompression bottom time available due to nitrogen accumulation. The same principle applies to oxygen at deeper depth. The greater the depth, the shorter the bottom time.