Submersible Titan implodes, killing passengers. What were the health risks on board?
Key Takeaways
Tourist submersible the Titan has been lost for three days. Today, debris was found from the submersible, confirming that the passengers are likely dead.
The Coast Guard has said the search will continue to help answer what happened to the sub and the people onboard.
The passengers on the submersible Titan are assumed dead after debris has been found near the site of the previously sunken Titanic, according to the Coast Guard. The Titan, a tourist submersible, went missing three days ago. It was feared the passengers ran out of air before the submersible likely imploded. Now, its voyage could become a modern travesty.[]
As of Thursday afternoon, the Titan’s tour company, OceanGate Expeditions, said it believed all passengers to be dead—but the Coast Guard maintains that the search for the vessel is ongoing.
Search crews have been working to locate and rescue passengers but have not made contact.[]
Hypoxia risks on sub
Among other variables, oxygen levels in the submersible are imperative to the crew’s survival. According to the US Occupational Safety and Health Administration (OSHA), humans begin to suffer adverse health effects when the air's oxygen level drops below 19.5%, which is considered to be oxygen-deficient. At this level, a person can last mere minutes before the death of brain cells, and eventually, the body occurs. Brain cells can begin to die after one minute without oxygen, and at 10 to 15 minutes, a person may be unable to recover, according to the University of Michigan Transplant Center.[][]
“Once you hit those levels, there will be a time-window where they may be unconscious and have some ability to be saved, but that's gonna be a small window,” says James Keany, MD, emergency medicine doctor at Providence Mission Hospital in Orange County, CA. “It's not an ‘on-off switch,’ but it's a relatively rapid decline once you hit a percentage of air that's not going to maintain enough oxygen for your mental status and your organs.”
The 96-hour estimate may be based on factors such as the vessel’s design and the number of passengers using oxygen, says Kearny. He adds that there is a chance that this time frame could be expanded if the crew has been taking steps to conserve their oxygen use, such as limiting their movements—or if some of the members have already died.
“Those estimates are made after pretty careful consideration, so I wouldn't imagine that there's a lot of extra time unless there's something going on—like if two of the people died in the accident that occurred, and there was a much lower consumption of oxygen at that point,” says Keany. “That's a pretty morbid thought.”
He adds that the Titan’s oxygen supply could have depleted under 96 hours in another unfortunate scenario. Something like this could have occurred due to a potential breach in the hull, which would have allowed water and underwater elements to seep into the structure and expose passengers to deadly scenarios like drowning plummeting body temperatures, or the impacts of deep-sea pressure, he says.
If the hull has or does break due to pressure or other elemental reasons, “that would be a catastrophic failure of the sub, and then they would be immediately exposed to the external environment and drown,” adds Keany. “Assuming the structure is intact, the hull hasn't been compromised, [and] the people have been able to maintain their space within the sub, the more dramatic factor is the [internal] environment,” he adds—the most timely factor being oxygen supply.
Hypothermia risks on sub
Temperatures drop in deep sea levels. This sub was destined to reach 4,000 m below sea level, which is on the cusp of two levels of the ocean: the Bathypelagic Zone and the Abyssopelagic Zone. The temperature in the Bathypelagic lingers around 39 degrees Fahrenheit, or 4 degrees Celsius, while the temperatures in the Abyssopelagic Zone hover near freezing, according to the National Oceanic and Atmospheric Association.[][]
Going into a state of hypothermia could help passengers protect themselves from the elements, as the body conserves energy in this state, says Keany. However, hypothermia also poses dangers.
Both hypothermia and hypoxia can impact brain activity, decreasing a person’s mental status and ability to make good decisions, says Keany.
“You start losing a good sense of reasoning and logic as your brain shuts down from hypothermia,” he adds.
Whether hypothermia or hypoxia could take over sooner is likely dependent on the design and mechanics of the sub, many of which are unknown, Keany says.
Is recovery of human life still possible?
Though it is unlikely at this time in the recovery effort, if the sub is found and passengers are recovered and alive, they will likely need immediate medical attention, starting with placement in pressurized dive chambers that match the pressure levels set by the Titan, Keany says.
Dive chambers can be designed as multi-person or single-person structures and used to help the body slowly assimilate to sea level, he adds.
Heated blankets and other specialized supports should be used, if needed, for hypothermia. Fluids and oxygen supports—ranging from tubes to ventilators—could also be necessary, he says.
If alive, whether or not passengers will maintain brain damage is unclear, Keany says.
“The window between starting to have brain damage and actually dying is a small window,” he adds. “Likely, we're either going to deal with a rescue of somebody who's in relatively good condition and fully recoverable, or a recovery of bodies.
The search continues
Reports have suggested that the Titan’s white color, coupled with its deep submersion, makes it increasingly difficult to find compared to typically vibrant orange- or yellow-colored submarines. Safety experts argue that submerged vessels should be evaluated with safety standards similar to those applied to space voyages and stress the need for a future assessment to determine if the vessel was safe and “seaworthy” in order to avoid such travesties in the future.[]