Divers Die, Part III

In our ongoing analysis of U.S. and Canadian recreational diving fatalities reported by Divers Alert Network, we’ve focused on some of the common causes of deadly accidents, such as panic, entrapment, and poor judgment by divers, instructors or divemasters. In this issue we’ll examine the dangers of running out of breathing gas, rebreather malfunctions, and what can happen when a hunter turns into a victim.

Running on Empty

Loss of gas supply was a problem in at least 29 fatalities in 2003. In a disturbing number of cases, divers went diving with partially full tanks. A 54-year-old advanced certification student began a shore-entry training dive in a lake, with less than 1,000 psi – an unthinkable mistake in an instructor-led course. The student descended to 82 feet, complained of being cold and quickly exhausted his air supply. The instructor released the student’s weight belt during the ascent, and the diver passed out before reaching the surface. Resuscitation efforts failed.

Even if a tank isn’t sucked dry, getting low on breathing gas can lead to other dangers, such as rapid ascents. An experienced 40-year-old open water diver made a shore entry with a tank that was less than half full. Because he had less air than his buddy, they quickly separated as the buddy with more air descended past 100 ft. The two reunited briefly but again went off in different directions. The buddy surfaced but couldn’t find the other diver, whose body was recovered later. His death was due to an air embolism, perhaps caused when he realized he was low on air and shot for the surface.

Five deaths involved solo divers who could not get help, such as a 51-year-old male who had completed approximately ten dives since becoming certified. Without a buddy, he made a pair of shore-entry dives to 70 feet, but didn’t use a full tank for the second dive. Observers saw him struggling at the surface and calling for help. He removed some of his equipment before disappearing below the surface, eventually dying of an embolism.

If you’re not diving with a full tank, you’re not playing with a full deck.

But even with a full tank, divers need to monitor their consumption. A 28-year-old male making a wreck dive in 67 ft. failed to do that. He ran out of Nitrox and was making his way back to the boat using the surface line. Although he was handed his buddy’s buoyancy compensator because he didn’t have enough gas to inflate his own – whatever happened to oral inflation? -- the diver slipped below the surface. They recovered his body two days later. He had a technical diving certification, but had completed fewer than 20 lifetime dives.

Fifty-six percent of the 2003 DAN fatalities involved divers returning to the sport after one- to- four-year layoffs. A regulator free-flow proved fatal for one such lobster diver, who had not made a dive in a year. He developed a regulator problem on a night dive to 65 ft. When he was down to 300 psi, he signaled his buddy that he wanted to ascend. The buddy saw the 40-year-old diver at 10 ft., but not at the surface. When his body was recovered the next day, a catch bag with 20 pounds of lobsters remained attached to him. DAN concluded: “The additional drag from the catch bag... would have contributed to the rapid use of the diver’s air supply.” And, of course, it would have dragged him down, as well.

Another infrequent diver and a buddy were trying to recover a sunken outboard motor from a lake bottom. They separated in poor visibility, and only one diver surfaced. The 45-year-old victim was recovered two days later at a depth of 90 feet with an empty tank. He had been certified five years previously but had not been diving in more than a year.

Hunting Proves Fatal

Spear fishermen and game collectors accounted for 15 percent of the reported fatalities. Many were on solo dives. An experienced 23- year-old was using Nitrox to make a series of dives more than 110 ft. to spear fish. On his fifth dive, without a buddy, at 122 ft. he speared a large grouper and made a rapid ascent. He descended again and, while the speared grouper rose to the surface, the diver did not. Another diver went down and pulled the stricken diver to the surface, with a stringer full of grouper attached to his body. His tank was empty and he never regained consciousness. The diver who helped required treatment for decompression sickness (DCS).

Although DAN reported several cases of DCS, none proved fatal to U.S. or Canadian divers. But the British Sub-Aqua Club, which has issued its own report of fatal accidents in the UK during 2003, recounts a chilling tale of a group of divers on a wreck at 63m (207 ft.). After getting into some unspecified trouble at depth, one diver surfaced without doing any decompression and a second missed half his required stops. They were airlifted to a recompression chamber where the diver who had missed all his stops was declared dead on arrival. A third diver failed to surface at all. The following day his body was found on the seabed, entangled in netting.

Rebreathers Require Special Handling

Diving Medical Specialist David Sawatzky, MD, has published a study of 25 documented fatalities involving rebreathers, and has concluded that some fatalities are due to stupidity, some are from lack of experience, and some are similar to open-circuit accidents, such as myocardial infarction, arterial gas embolism, rare decompression illness, running out of breathing mix, and getting trapped. None of these deaths was the fault of the rebreather, Sawatzky concluded.

Unfortunately, as rebreathers become more popular, more divers are dying while using them. Rebreather rigs require meticulous maintenance, and errors in assembly may have tragic consequences, as with a very experienced 40-year-old technical diver, who made a quarry dive at night using a rebreather with Nitrox as his breathing gas. A group of twelve participated, and when the rest of the divers surfaced, one was missing. He was found, unresponsive, at 15 feet. An examination of the rebreather revealed that there was carbon dioxide absorbent throughout the rig, an oxygen sensor had been inserted incorrectly and was not functioning, and the oxygen addition valve was partially blocked, resulting in a 75 percent decrease in flow. There were also several loose connections.

Another techie, who liked to dive alone, pushed his luck too far on a wreck dive in a four-person buddy team. During the dive, the 58-year-old went off on his own. That did not alarm his buddies, since this was his habit. However, when he was found unconscious on the bottom in 104 ft., the rebreather was out of breathing gas, yet his “bailout” pony bottle was full. Solo diving adherents stress the need for self-reliance, but something prevented this diver from getting himself out of trouble.

That may also have been the case with an experienced advanced diver using a rebreather on a live-aboard. He did not appear to have a designated buddy, and had been prolonging his dives long after the other divers had exited the water. (Some of his previous dives lasted up to two hours.) But on his last dive, the 41- year-old diver never came back, and his body was never recovered.

David Rampersad, a certified instructor for the Scuba Network dive shop in Carle Place, NY, was found unconscious in four feet of water while testing a rebreather in a high school swimming pool last May. According to the New York Daily News, Rampersand had said he was having problems with his Azimuth semiclosed circuit rebreather and wanted to check it out. Three other dive instructors from the shop were teaching a class at the pool that day, and one spotted Rampersad unconscious, his mouthpiece out of his mouth. They pulled him out and attempted CPR, but he was pronounced dead at a nearby hospital.

It’s clear that anyone using a rebreather needs specialized training and continued practice. Although we use them for fun, rebreathers and other scuba units are our most basic life support systems. . .not toys.