He Was 330 Feet Deep Without Anything to Breathe -- and Survived

When someone dies while scuba diving, inevitably the autopsy reveals drowning, even if it was only the final episode in a sequence of events leading up to the fatality. It's not a surprise. However, miracles can happen underwater, and a rare, lucky diver can be brought back from the dead. That's the subject of a new British documentary, Last Breath, which tells the story of a commercial diver who survived against all odds after being deprived of air. Science tells us the human body can last for only a few short minutes without oxygen -- he lasted 38 minutes.

On September 18, 2012, saturation diver Chris Lemons was 330 feet below the surface, fixing pipes at an oil well off Scotland's eastern coast, while breathing heliox, a helium-oxygen mix. It was supplied from his support boat, the Bibby Topaz, via an umbilical pipeline that also provided essential warming water for his suit, and communications with his supervisor. But when its positioning system failed, the Bibby Topaz broke free in the North Sea's turbulent waters, and Lemons and other divers were dragged from their work site.

While the others were able to make it to the safety of their submerged hyperbaric chamber, known as a "diving bell," dangling from the ship, Lemons' lifeline got snagged on a piece of metal sticking out of the oil well, and was severed. He was wearing an emergency backup life support system in the form of a closed-circuit rebreather, but he knew that at that depth, its gas supply was only good for a few minutes. Climbing the submerged oil rig on which he was working, Lemons was dismayed to find the sanctuary of the diving bell had gone with the support vessel.

It took around 30 minutes to get the Bibby Topaz back into position, by which time the other divers, safely in the diving bell, assumed they'd be engaged in a body recovery. They launched a remote-controlled submarine in the hope of finding Lemons, and when it did, they watched helplessly on its cameras as Lemons' movements gradually stopped, his life fading away.

Once the other divers returned to the spot where he lay, they dragged Lemons' body back into the diving bell. Common sense told them he must have perished, but what could they do but attempt to resuscitate him? They removed his diving helmet and gave him two breaths of mouth-to-mouth. Miraculously, Lemons came around, conscious.

Now, nearly seven years later, Lemons continues to work as a saturation diver, but is still perplexed as to how he managed to survive so long, at that depth, without oxygen. It appears to be a combination of organs and blood still saturated with oxygen from his heliox supply, combined with a North Sea water temperature averaging 37 degrees that quickly cooled his body and brain once there was no hot water flowing through his suit, that conspired to allow him to survive.

"The human body doesn't have a great store of oxygen, maybe a couple of liters," Mike Tipton, head of the Extreme Environments Laboratory at Portsmouth University in England, told BBC Future."How you use that up depends on your metabolic rate."

"Rapid cooling of the brain can increase survival time without oxygen. If you reduce the temperature, the metabolic rate drops. If you lower the brain temperature down to 30 degrees Celsius (86 degrees Fahrenheit), it can increase the survival time from 10 to 20 minutes. If you cool the brain to 20 degrees (68 degrees Fahrenheit), you can get an hour."

Lemons' survival is not unheard of, either. Tipton examined 43 separate cases in the medical literature of people who have been submerged in water for long periods. Four of these recovered, including a two-anda- half-year-old girl who survived being underwater in a cold lake for 66 minutes.

Last Breath is available to watch on Netflix. And you can see an interesting 28-minute Q&A with Lemons and the filmmakers on YouTube at www.youtube.com/ watch?v=7i78bozHZD8