Enriched Air NITROX is any AIR mixture where the Oxygen content is greater then the 21% we normally breathe. The two most common mixtures are 32% and 36%, otherwise known as EANx32 and EANx36.

The principle reason for breathing Enriched Air NITROX is to extend No Decompression Limit bottom times. As divers we are often required to return to the surface because of Nitrogen absorption. With Enriched Air NITROX we are inhaling less Nitrogen and therefore absorbing less Nitrogen and our NDL bottom time increases. For example, on a dive to 50 feet the AIR NDL is 80 minutes. That same dive with EANx32, our allowable bottom time is increased to 155 minutes and with EANx36 it increases to 220 minutes. Pretty dramatic difference!!

Enriched Air NITROX can also help in other ways, since Nitrogen absorption is responsible for De-Compression Sickness (or the BENDS), if you absorb less Nitrogen, you can reduce the amount that’s in your system and therefore reduce the chance of suffering from DCS. You still need to come up slowly from every dive and follow all the other Golden Rules of diving. You can also reduce surface interval times using Enriched Air NITROX. If you’ve inhaled less Nitrogen then you need less time to off gas Nitrogen on the surface. Another of the side benefits to Enriched Air is the reduction of that NITROGEN NAP feeling which is common after diving with Air.

It all sounds good, but there must be a down side . . . right?

With Nitrogen TIME is the limiting factor, but with Oxygen DEPTH is the limiting factor. The maximum depth limit for Air is 218 feet, with EANx32 it’s 130 feet and EANx36 it’s 110 feet. When you consider that most of the diving we do as recreational divers is in that 30 to 100-foot range anyway, it’s not much of a limiting factor. But the consequence of going too deep is OXYGEN TOXICITY, which is very serious and can result in seizures and drowning.

However, all you have to do is ...
Receive the Proper Training
Dive Responsibly
Observe the Depth Limit for that mixture

And you will never have to deal with the down side of Enriched Air NITROX.

NEVER DIVE ENRICHED AIR NITROX WITHOUT THE PROPER TRAINING

Common Question and Answers about Enriched Air Nitrox:

Do I have to be Enriched Air NITROX certified to dive NITROX?


No. Seasport Divers participates in the PADI Introduction to Basic NITROX program. You are required to be a certified diver, be at least 15 years old, complete a medical questionnaire and dive with a Nitrox Instructor. You will learn the NITROX basics; the maximum depth limit for the mixture you are breathing, how to read and operate a NITROX computer and how to analyze the mixture you are going to use. The instruction can be done at the shop before you go diving or on the boat during the short trip to the first dive site.

Can I get Enriched Air NITROX certified?

Yes. Seasport Divers offer both PADI and TDI Enriched Air Nitrox classes. Both can be done in a short day and the PADI course requires that you make two NITROX dives.

Do I need a special regulator?

If you are diving with Oxygen content less then 40% and your regulator is kept well maintained, you can use your normal regulator. Anything over 40% requires special gear.

How about my BCD and low-pressure inflator?

The same as your regulator, if you are diving with Oxygen content less then 40% and your BCD is kept well maintained, you can use it with no problems. Anything over 40% requires special gear.

Can I dive deeper with Enriched Air Nitrox?

No. There are a lot of people that think Enriched Air NITROX allows you to dive deeper. The opposite is true; Enriched Air actually has DEPTH LIMITS to keep you safe from suffering OXYGEN TOXIXITY. In a Enriched Air NITROX class you will learn how to calculate the maximum depth limits for any Enriched Air mixture.

Will Enriched Air NITROX increase my bottom time?

Yes and No. It will not make a tank last longer, if you suck down an air tank you will suck down a NITROX tank too. But it will lengthen your No Decompression Limits and allow you to stay down longer, air allowing of course.

Can I still get the bends with Enriched Air NITROX?

Yes, but since you absorb less Nitrogen and that’s the main cause of the bends, Enriched Air decreases the possibility of that happening. You still need to come up slowly from every dive and follow all the other Golden Rules of diving.

Does Enriched Air Nitrox eliminate Nitrogen Narcosis?

There is no definitive answer on that one. More study is required to determine if that is true or not.