:I don't know how that got in there. The probable reason for the popularity of EAN32, a least as a boat-concentrator supplied gas (and for which I don't have a reference) is that EAN32 doesn't give you a ppO2 over 1.6 bar at any depth you're likely to be at in "sport diving" (130 ft, in turn set by narcosis concerns on air). Or even over 1.4 for any depth you're likely to be at for more than a couple of mintutes. Sport divers hardly ever go below 110 ft (it's dark and spooky and cold) and if they do, it's only for a minute or two (some usually looking a some unusually interested thing on a wall, in very bright sun and very clear water). This makes your wrist computer howl and your buddy and divermaster start buzzing and tapping their tanks, and it's just not something that divers do for long (it also uses gas like mad, so everybody knows it will cut your dive short and make you have to swim shallower than your group for the rest of the dive, trying to conserve gas, thus missing all the interesting reef stuff they are seeing). So EAN32 is extremely unlikely to kill anybody from ox-tox seizures, even if misused and mistaken for air in sport diving as it's usually done in groups. And that is probably why many resorts are so happy to supply it, when supplying gas for refill lines off a main live-aboard. If you screw up and refill with EAN32 for somebody who really isn't nitrox certified, it's very likely that no harm will be done anyway.