Why Divers Die, Part I

No one likes to think about diving fatalities, but as we all know, they happen. Undercurrent periodically reviews specific cases reported by DAN, to see what we can learn about preventing such tragedies in the future. What's apparent is that virtually every fatality DAN studies could have been avoided by better preparation, conditioning, or common sense. Here are a few cases from their 2003 report.

BC Problems, and Poor Maintenance

Misused or poorly maintained equipment contributed to buoyancy control problems implicated in several fatalities. In these cases, equipment maintenance might have been the difference between life and death.

A 58-year-old diver using a rebreather with a dry suit made a shore dive to 300 feet. He encountered buoyancy problems during his ascent, so he headed directly to the surface without decompressing. As it turned out, the inflator to his dry suit was significantly corroded, likely creating difficulty in dumping air. He was taken to a recompression chamber but died during treatment.

An experienced, 40-year-old diver was making a buddy dive to look for fishing lures in a freshwater pond. They went down to 15 feet and separated, according to their dive plan. The decedent surfaced and called for help. He then dropped below the surface, fins up. Fishermen came to his aid, but he could not be resuscitated. A later equipment evaluation revealed that his regulator was in poor repair and failed in the closed position (unusual for a regulator) due to a loose screw. His buoyancy compensator could not be inflated, and there were weights in the pockets. He didn't have a depth gauge, and the mouthpiece on his second stage had holes in it.

Thirty-five minutes into a wreck dive with eight others, this 42-year-old, trained tech diver was found unconscious at 112 feet. He couldn't be resuscitated. The diver, an instructor who worked in a dive shop, filled his own tanks. Yet a post-mortem check revealed that one of his two tanks contained less than one percent oxygen, as well as several ounces of rusty water, and had extensive rust and pitting throughout its inner surface. The oxygen that had been present in the tank had likely been consumed in the oxidation process. The tank did not have current visual inspection and hydrostatic testing.

Just Say No to Diving

There are all sorts of circumstances when a diver should just flat out scrub the dive. Unfortunately, divers often ignore them. Here, self-denial of one's own physical problems proved the culprit. This 48-year-old, open water diver had vision so poor that he had to ask his buddies to read his gauges for him (he did not dive with corrective lenses). After completing a dive to 40 feet for 20 minutes, he showed his gauges to one of his buddies and ascended to the surface alone. He surfaced, struggled, and yelled that he was out of air before swimming toward a floating line. Then he lost consciousness and sank below the surface. An autopsy showed evidence of cardiac disease, though death was due to drowning. Now of course this diver should not have been diving. But how could his buddies buy into his disability and become accomplices?

An experienced, 48-year-old diver had symptoms consistent with DCS from a deep dive the previous day, but declined any medical evaluation. Then he entered the water without a buddy and rapidly descended to 166 feet. His body was recovered nearly three hours later. The diver's tank was empty and, despite using Nitrox, his depth would place him at risk for both nitrogen narcosis and oxygen toxicity.

A 39-year-old diver with a history of DCS was participating in a spearfishing contest and made five solo dives to greater than 165 feet. He had computer and buoyancy compensator problems and took minimal surface intervals, exceeding the limits of any computer or table. He experienced DCS symptoms before his last descent, but he made the dive anyway. After surfacing, he complained of respiratory distress and was taken to a local recompression chamber, where he died. While the medical examiner certified the cause was an air embolism, his dive history and symptoms were consistent with cardiopulmonary DCS, often called the chokes.

Though he was seasick before entering the water, an experienced but obese 42-year-old planned a 100-foot wreck dive on Nitrox without a buddy. He made it down to 28 feet and surfaced three minutes later without his regulator in his mouth. He was talking on the boat before losing consciousness. Resuscitation efforts were unsuccessful.

A 64-year-old female with extensive diving experience had a medical history that included hypertension and arthritis and had complained of extreme fatigue following the previous day's diving. After the second dive of the day, she and her husband surfaced in rough seas. As the dive boat crew helped the divers, they saw her below the surface unconscious. Resuscitation efforts were unsuccessful. Her tank was empty, and her buoyancy compensator would not hold air, but the investigators were not sure that the damage to the BC existed before the rescue efforts to get the stricken diver into the boat. The cause of death was air embolism.

A 49-year-old student in an advanced open-water certification course with 15 lifetime dives made a shore entry night dive and carried his mask and fins into the surf. When his buddy returned to the beach, the decedent continued the dive. No one saw him again until his body was recovered without his mask and fins. While a cardiac event cannot be excluded, walking into the surf without mask and fins is nearly suicidal.

Shark Attacks

Shark attacks on scuba divers are rare, but DAN reports one possible death by shark attack. After getting separated from his buddy on a 268-foot tri-mix wreck dive, a 42-year-old, technical diver's body wasn't recovered for four days and suffered "extensive post-mortem animal predation." At least one shark bite might have occurred when the diver was still alive.