NitroxVoodoo gas.
Or: the most useful specialty in recreational diving, and why we include it as standard.
“The gas once considered too dangerous for recreational divers is now the most popular specialty PADI teaches.”
Nitrox is the gas that was once considered too dangerous for recreational divers, and is now the most popular specialty PADI teaches. That shift took about five years in the 1990s, and it happened because the fears were wrong. The training works. Once you've dived on it, the case for going back to air on most recreational dives is weak.
What it actually is
Nitrox — or enriched air, or EANx — is air with more oxygen in it. Regular air is 21% oxygen, 79% nitrogen. Nitrox is typically 32% or 36% oxygen, with correspondingly less nitrogen.
That's it. No exotic chemistry, no special gas. Just air, tuned for diving.
The practical effect is simple: less nitrogen going into you means less nitrogen coming out, which means longer no-decompression times, reduced fatigue across a multi-day trip, and more options for how you plan your dive day.
What it actually is.
Air, tuned for diving. More oxygen, correspondingly less nitrogen — no exotic chemistry.
At 18 metres: 56 minutes on air, 95 on nitrox.
It can make a big difference.
The thirty-nine minute argument.
Air at eighteen metres gives you fifty-six minutes before you owe a stop. Nitrox 32 gives you ninety-five.
The voodoo gas era
In 1991, the editor of Skin Diver magazine — then the biggest diving publication in the world — coined the phrase voodoo gasfor nitrox. The annual dive industry trade show banned nitrox training providers from attending. BSAC banned its members from using it. PADI's own official statement read: “PADI does not sanction gas mixtures other than air for recreational diving at this time.”
The fear was that recreational divers couldn't be trusted with the oxygen-toxicity risks that come from using richer mixes at depth. Training, the argument went, would need to be too technical. The gas was fine for the US Navy and for commercial divers, but not for someone on holiday.
NAUI broke ranks in 1992 and started teaching it. PADI held the line for another four years before finally capitulating in 1996. Since then, nitrox has gone from banned, to permitted, to standard — and PADI's own Enriched Air Nitrox specialty is now the single most popular course they teach.
From banned to standard, in five years and a bit.
The fears of the early nineties did not survive contact with the training. The gas didn’t change; the industry did.
“The theory should be part of how divers are taught from the start — not something to come back for later.”
A more rounded understanding of decompression theory — and how nitrogen actually behaves in the body.
You give up depth. You get time.
The richer the mix, the longer your bottom time — and the shallower your maximum operating depth. The choice is the dive itself.
Why we include it as standard
Here's my take, for what it's worth.
Nitrox isn't an advanced technique. It's a safer way to do the same dives you were already going to do. Less nitrogen loading across repetitive dives, a bigger safety margin on your no-decompression limit, and — at least in my experience, and a lot of divers will back this up — less fatigue over a multi-day diving trip.
There's another reason I think the certification matters, and it's not often talked about: learning nitrox gives you a more rounded understanding of decompression theory and how nitrogen behaves in the body. The Open Water course introduces the basics. Nitrox goes further — whynitrogen is the issue in the first place, how gas mixes interact with depth, how your computer's no-decompression calculations actually work. That knowledge makes you a better diver even on the days you're diving on air.
My view is that the theory should be part of how divers are taught from the start, not something to come back for later. That's why we include the certification as standard in every Foundation, Explorer, and Rescue course we run — whether or not you end up choosing to dive on nitrox afterwards. We'd rather you know the material, understand the trade-offs, and make your own call dive by dive. That's closer to how diving should be taught, and it's a small part of what we mean by north of ordinary.
Less in. Less out. Less waiting.
Lower nitrogen loading on each dive means shorter surface intervals between them — and a less tired diver at the end of the day.
The course itself
The PADI Enriched Air Nitrox certification is a one-day course. eLearning covers the physiology, gas analysis, and planning. An in-person Theory Workshop runs through the material alongside, and as a standalone course we always add two confirmation dives so the theory settles into practice before you leave.
- Certification
- PADI Enriched Air Nitrox
- Duration (approx.)
- 1–2 days (theory + two confirmation dives)
- Prerequisites
- PADI Open Water (or equivalent), minimum age 12
- Included
- Every Foundation, Explorer, and Rescue course, unless already held