August 11, 1974 - October 12, 2002: Age 28
Audrey Mestre was a French world record-setting free diver who died in an attempt to set a world record of 171 metres.
In the sport of freediving, the diver descends vertically under water as far as possible, then reascends to the surface, on just one breath. This is achieved using a weighted sled tethered to a strong line. Holding on to the sled, the diver shoots downward to a give depth. At the bottom the diver uses a small air tank to inflate a balloon and, holding the balloon, shoots back up to the surface. Safety divers in scuba equipment are positioned at regular intervals and at the bottom to assist in case of mishap.
Nitrogen narcosis, the condition that makes deep diving risky for scuba divers, is not a problem because descending and ascending on one breath leaves no time for nitrogen to build up in the bloodstream. However training for the sport is necessary to make it possible for go without air for three minutes, and to survive surviving high ambient pressure that would normally cause permanent damage to the lungs.
The first part of the dive went as expected, but at the bottom of the dive Mestre discovered that the small tank that was to be used to fill the balloon for the ascent was nearly empty. The safety diver used some of his own air to partially fill the balloon, allowing her to leave the bottom, but it wasn't enough to get her all the way back up, and she lost consciousness about 100 feet below the surface. Safety divers positioned part way up managed to get her the rest of the way, but not before she had been without oxygen for nearly nine minutes. She never regained consciousness. Her death was ruled an accident.
A year after her death one of her friends and team members came out publicly to accuse her husband, also a free diver and in charge of the team, of negligence at best and, at worst, deliberately planning his wife's death. Nobody seems be clear whose responsibility it was to fill the tank for the ascent balloon. Other safety measures that might have saved her life — a doctor at the surface, spare air tanks at stations on the way up — were not in place. The husband and the team member have published competing books, each with their own version of events. The dispute is emotional, rancorous, rather sad, and quite interesting.
Sources: Wikipedia, US News, The Last Attempt