NITROX IS INTOX by FRANCIS LE GUEN

The mood of Francis Le Guen

Because sometimes, do not mess around!

Music credits: Erwan & Eric Le Guen

I don't like Nitrox! It's like that ! It should be noted right away that I am not a novice in the use of gas mixtures for diving. I was already using Nitrox at different percentages of O2 as early as 1980, for decompression procedures, during long exploration cave dives. And long before “enriched air” became fashionable… It should also be noted that this humorous post, deliberately controversial, does not concern the use of rebreathers and other “Tek” dives where Nitrox is of course of common use.

No, I want to talk about this flowering of yellow and green bottles in the centers, presented as a panacea. The essential use of Nitrox in recreational diving. From you to me: what interest? Officially, this allows for fewer steps. Is. But usually, do you do a lot of you, diving-leisure bearings in the air? How many, 10 minutes? And is it so painful?

Me, I like the bearings. An old habit. In underground diving, I happened to make 7h in a row. And Oxygen ... Do some bearings at the end of the dive, it's very good for health. It's an excellent habit that becomes a reflex. This gives a better control of buoyancy and prepares for the din of earthly life. And it is often the opportunity to quietly observe all the fauna: jellyfish, salps, macroplancton, when it is not about mantas, dolphins or whale sharks. Frankly: floating in weightlessness in the sun-scorched water is sometimes the best time to dive. No ? And again, we only talk for a few minutes! Even in cold water, it's a joke. So, what is Nitrox doing in history?

The French invented diving, but the Americans taught the rest of the world to sell it. And as always, this detestable fashion came from America… Because, of course, to practice Nitrox diving it was necessary to create filling stations, computers capable of calculating the levels for these mixtures ( which makes them more complex and sources of error for novices, moreover). “Special” regulators, books, internships… All of this keeps the business going. It is a fact that enriched air impoverishes us: certification, inflation, all of this is more expensive and that is the goal sought by these promoters.

So of course, the use of these bottles stamped yellow and green gives a little air "tek" to the average diver. But ultimately the term is quite pretentious when you consider that the air of God is already 21% Nitrox… What snobbery! I am going to make some mixtures for you ... Nitrox, not too little ... Nitrox at 21,5%, for the breathless ... 20,5%, for the Swiss, who are always at altitude ... Joking aside, when from my “mixing period”, at the time when it was not as easy as it is today to obtain the “recipes”, I even tried Argox, Neox, Krypteliox… Sponsored by a brand of industrial gases, I didn't have to pay for them, these rare gases… Note that I did the tests in a box: not quite crazy anyway… You want sensations? So dive into the Trimix! With Hydreliox… Well, everyone does what they want.

No, what bothers me the most about the trivialization of Nitrox is the depth limit it imposes, by definition. It may be well suited for flat bottoms not exceeding 20, 30 meters but what about vertiginous drop offs? Whoever has never caught a beginner in free fall throw me the first pebble ... Will you risk hyperoxia to rescue someone? Certainly not. While in the air, the margin is more comfortable to intervene.

It was on a beautiful drop off in the Red Sea. Too many teams, instructor in mind, I was a tether. Instructions: we advance in a straight line, no one exceeds 30m. Well ... Except that the guy in front of me seems a little too weighted, burdened as he is with his big box with flashes and lamps. And here he is coming down to frame a magnificent bush of soft corals, "a little lower" ... Pass again, I'm watching. It resumes its course but obliquely, towards the bottom. I'm already 35 m away to get closer, just in case ... He flippers like a nag and realizes that he is too heavy. No doubt a little narcotic, I see him flirting in the void in search of his direct system. And now he is purging his vest instead of inflating it! Big bubbles… He pedals in the sauerkraut and continues to probe into the blue. I picked it up 62 meters away ...

In the air, at least, we are sure of what we breathe. Nitrox, you have to control the PO2, the percentage. Be sure the equipment is calibrated. That the diluent is nitrogen. Adjust your computer. Many constraints, many sources of errors ...
In the conference he recently gave at the Timone hospital in Marseille, Doctor Mathieu Coulanges reminded us of this “Nitrox paradox”. Indeed, originally designed for more safety, it is clear (in the statistics) that it actually increases the number of accidents. For example, some ADD are due to divers who forget to reprogram their computer to "air" after having dived during a whole stay with Nitrox ...

And so many constraints and prerequisites: Nitrox is not recommended for elderly divers, hypertensive, it worsens dehydration, increases the difficulty for balancing the eardrums ... But above all, it encourages people to go beyond limits. Known air: "we are on Nitrox, we have a good safety margin for the decoration", so we pull a little on the time spent at the bottom ... Box which is deducted!

I know that for those who dive a lot, it is also a way to limit fatigue. Less saturate and reduce the risk of accidents. Is. But again, we are very far from recreational diving ... And all things considered, I still prefer to dive in the air and decompress with pure oxygen. Nitrox for everyone? It's intoxicating!

Come on, I wish you a good vacation! Take a breath of fresh air ...