What’s More Dangerous, the Rebreather or the Diver?

Ken Kurtis, owner of Reef Seekers Dive Company in Beverly Hills, CA, took issue with this sentence in John Bantin’s piece on rebreathers in our March issue: “The use of a rebreather statistically appears to increase the risk in the hobby of scuba diving.” Kurtis says that’s a simplified statement that may not be entirely correct.

“It could be that rebreather divers are engaging in behaviors (deeper, longer, more complex mixes) inherently more dangerous than diving on air. Because they’re not doing the 30-minute, 30-foot reef dive, the ‘safer’ dives are not part of their mix, and their accident rate appears higher. So it’s not that rebreathers are more dangerous, it’s that divers are doing more dangerous things and happen to be on rebreathers. It’s like playing Russian Roulette: The more often you spin the chamber, the greater your chances are of finding the chamber with the bullet.

“It could also be that rebreathers attract a segment of thrill-seeking divers more willing to engage in risky behavior. Or perhaps people who are drawn to rebreathers generally don’t have the discipline required to use such a complex machine. The guy who runs out of diluent in his rebreather is likely to be the same guy who runs out of air in his scuba tank. That he did it on a rebreather may be nothing more than a coincidence.

“We had a guy here in L.A. who turned off his rebreather electronics between dives because he wanted to make the battery last as long as possible and save money by not changing it as often. Guess what happened? On his final dive, he forgot to turn the units back on, descended to 100 feet, likely went unconscious within five minutes from the buildup of carbon dioxide in the breathing loop, and died never knowing what hit him. So I think when you look at these types of accidents, you have to look at the equipment, circumstances of the dive and the diver. The totality of that needs to be considered before jumping to any conclusions. And from a statistical analysis point of view, there simply isn’t enough data to draw any reliable conclusions.”

John Bantin replied: “That misses the point. Saying the man who runs out of diluent is just as likely to run out of opencircuit gas is not addressing the problem, that it is not how much gas you’ve got but what the gas you are breathing is composed of. Carbon dioxide or oxygen poisoning are insidious dangers, and rebreathers require the discipline of a helicopter pilot in preparation to be safe. Has every diver got that? I think not! Many rebreather deaths have occurred at the surface or in very shallow water.

“The main thrust of my piece was the fact that many secondhand rebreather units are coming onto the market for private sale without any control as to whether the buyers gets properly trained before going diving with them.”