- The Titan tragedy joins the Byford Dolphin accident in history's most gruesome deep-sea incidents.
- Officials said the Titan submersible likely suffered a "catastrophic implosion" from a breached hull.
- 1983's Byford Dolphin incident was likely from faulty equipment that caused explosive decompression.
On Thursday, US officials confirmed they found debris that belonged to the missing Titan submersible.
The debris was consistent with loss of the pressure chamber resulting in a "catastrophic implosion" that killed all five passengers aboard, officials said. The Titan incident will go down in history as a deep-sea tragedy.
It joins the Byford Dolphin accident of 1983 — another deep-sea chamber compression incident but with a very different set of circumstances that killed five and injured one.
The Byford Dolphin incident
On November 5, 1983, four divers — Edwin Coward, Roy Lucas, Bjørn Bergersen, and Truls Hellevik — returned from a deep-sea commercial mission near the Byford Dolphin oil rig.
Saturation divers conduct construction or demolition work at 1,000 feet below the surface or deeper, according to Atlas Obscura. They work in hazardous conditions, including breathing in pressurized air that dissolves gases such as nitrogen inside their blood and tissues.
Similar to some other deep-sea or scuba divers, saturation divers need to allow that nitrogen gas time to leave the body before resurfacing. Otherwise, if a diver resurfaces too fast, the rapid reduction in pressure triggers the nitrogen gas to form bubbles in the blood and tissues that cause decompression sickness, aka "the bends."
If a saturation diver traveled 650 feet below sea level, for example, it would take eight days for them to safely resurface, according to Divers Alert Network. Because of that lengthy process, saturation divers often spend weeks deep underwater. That's exactly what the four divers involved in the Byford Dolphin incident were doing.
They were staying in two connected, compressed living chambers for weeks while completing a mission, IFLScience reported. When the four returned from the dive, diving tender William Crammond began the process of balancing the chamber pressure between the main living chambers and a room called the diving bell.
But on November 5, 1983, during one of these usual procedures, something went horribly wrong. It's not entirely clear what happened and why. A combination of faulty equipment and human error is likely.
Ultimately, it's thought that Crammond released the diving bell clamp, that sealed off the diving bell from the main living chambers, too soon. This rapidly changed the pressure in the living chambers from nine atmospheres to one, according to The Science Times.
The immediate change in pressure caused what is referred to as an explosive decompression. The nitrogen gas in the men's blood burst into bubbles. The four divers were "boiled from the inside" and died instantly, per The Science Times. The accident is considered one of the most gruesome in history.
Crammond also died in the accident. Martin Saunders, another diving tender, was the sole survivor but had devastating injuries and was in critical condition, according to Daily Science Journal.
A catastrophic implosion
When US officials discovered the debris of the Titan submersible, they noted that it looked as though a "catastrophic implosion" had occurred due to the "loss of the pressure chamber."
It's likely that the pressure hull was breached, but what caused the breach in the first place is unclear. Stefan Williams, a professor of marine robotics at the University of Sydney whose lab works with uncrewed submersibles, told Insider earlier this week that such an implosion could be due to a leak, power failure, or small fire from an electrical short circuit.
The submersible's design has also raised questions about its safety. Director and explorer James Cameron even said that reusing the submersible could "lead to catastrophic failure." Explaining that "Each dive adds more and more microscopic damage," Cameron told Good Morning America on Friday.
"So yes, they operated this sub safely at Titanic this year and the year before, but it was only a matter of time before it caught up with them," he added.
Cameron told ABC News that the vessel's censors warned the passengers of the danger. "We understand from inside the community that they had dropped their ascent weights and they were coming up, trying to manage an emergency," he said.
It's too early to tell if the likely implosion happened when the submersible lost contact with its mothership, about one hour and 45 minutes after launch, or later in its descent to the RMS Titanic. Either way, the pressure around the submersible would have been tens to hundreds of times greater than at sea level.
Unlike the divers near the Byford Dolphin oil rig, the Titan passengers didn't have any excess nitrogen in their blood. They probably died from the submersible imploding under the crushing pressure, which would have been the equivalent of the weight of the Eiffel Tower, experts told NBC.
In both scenarios, however, the men would have died almost instantaneously. "It would happen quite quickly, and there would be little chance of surviving," Williams said.