Since 1985 numerous articles and government notices have been released describing concerns about cylinders made from 6351 alloy aluminum. While the U.S. Government has determined no recall of the nearly 25 million 6351 alloy cylinders is warranted, annual inspection by trained inspectors is called for in the 1999 Department of Transportation (DOT) andNational Institute for Occupational Safety and Health (NIOSH) bulletins.
Our understanding of decompression science has undergone dramatic revision in the last two years thanks to decompression physiologist David Doolette, Ph.D. and the team at the Navy Experimental Diving Unit (NEDU).
Their report, “Decompression from He-N2-O2 (TRIMIX) Bounce Dives Is Not More Efficient Than He-O2 (HELIOX) Bounce Dives,” published May, 2015, dispels a belief about mixed gas diving that has persisted since the NEDU developed the first working heliox tables nearly 80 years ago.
In today's dive boats, you'd be hard-pressed not to see one or two of the telltale green and yellow tanks that announce the presence of nitrox, or oxygen-enriched air, which has been used in recreational diving for nearly 25 years.
Every major training agency has a nitrox training program in one form or another. But is it right for you? As with anything in diving, there are no absolutes when diving nitrox. Really, this gas is just like everything else in a diver's bag of gear and knowledge--a tool that can be effective when used properly and dangerous when not.