Lately there has been some chatter on another board about on-line nitrox training.  Some lament the passing of rigorous theoretical training that was originally part of nitrox training.  Others assert that a diver can learn all they need to know easily on an on-line course and have no need to visit their LDS or an instructor.  While I hesitate to get in the middle of this debate, there is supposed to be a practical session as part of every EAN course.  I believe that today many students are being short-changed on this important part of their EAN training.

I was privileged to get my training from Dr. Lee Sommers when he was traveling the country in the very early 90’s teaching Enriched Air Nitrox Divers courses to divers.  At that time there was a hot debate in the diving community over the safety of recreational divers using high oxygen partial pressure mixes.  Magazine articles called nitrox “voodoo gas” or “devil’s gas.”  Recreational agencies preached against it and dive shops refused to deal with it.  Consequently, the first courses were thorough, technically complete and exhaustive.  Now, with nearly two decades of use by recreational divers, the training has been greatly simplified. 

Recently I have noted a disturbing trend.  As I am teaching the entry-level technical course, Advanced Nitrox, I expect my students to analyze their gasses at the beginning of the day of diving.  (This is standard procedure in technical diving and, I believe, should also be in recreational diving.)   A large number of divers in my technical classes do not know how to use an oxygen analyzer.  I have also noticed that many do not understand why they should use different PPO2 levels (such as 1.4 ATA or 1.6 ATA) in different diving situations.  I have to teach them what they should have learned in their basic nitrox courses.  I don’t have a problem with adding this instruction to their course.  It is part of the review but it troubles me that so many recreational divers are not getting adequate training today for diving nitrox.

The practical portion of a nitrox course is supposed to include analyzing and logging out one or two tanks or EAN.  Many instructors are using the simplified analyzers that no not need calibration and only need to be held up to a slightly cracked-open tank valve to get a reading.  These are good devices to use in the field but most analyzers need to be calibrated and need to be connected to the gas source through some sort of plumbing that includes a flow restrictor.  I had one student tell me that during his EAN class the analyzer in the dive shop wasn’t working so they just skipped that part of the class.  When these “certified” EAN divers get out in the real world they have no idea how to use the tools available to analyze their tanks.  Consequently, they “trust” the labels someone else has placed on their tanks without checking. 

During the theory part of a basic nitrox class students should be learning about the huge affect exercise and the resultant CO2 buildup has on oxygen toxicity.  They do not understand why a PPO2 of 1.6 is ok for a diver at rest (deco) but a PPO2 of 1.4 or even less is recommended for the working part of the dive.  They only know that a PPO2 of 1.6 may be used for “contingencies.”  They believe that 1.6 is “safe.”  I frequently see divers making dives to 130 feet on EAN32.

I call on all instructors to make sure that all their nitrox students understand how to calibrate, connect and use a basic oxygen analyzer.   Instructors must also stress the importance of proper planning and limiting PPO2 values.