'Running out of oxygen not the only danger for missing Titanic sub'

LONDON: Running out of oxygen is not the only danger for the missing tourist submersible with five people on board, as the vessel might have even lost electrical power, experts have opined.

Speaking to the BBC on Wednesday, Ken Ledez, a hyperbaric medicine expert at the Memorial University in St John's, Newfoundland, said electrical power is likely to have a role in controlling the amount of oxygen and carbon dioxide inside the Titanic submersible, whose whereabouts remain unknown since June 18.

As the oxygen level falls, the proportion of carbon dioxide being breathed out by the crew will be rising, with potentially fatal consequences, Ledez noted.

"As levels of carbon dioxide build up, then it becomes sedative, it becomes like an anaesthetic gas, and you will go to sleep," he told the BBC, adding that too much of the gas in a person's bloodstream, known as hypercapnia, can kill them if not treated.

Meanwhile, former Royal Navy submarine captain Ryan Ramsey said he looked at videos online of the inside of Titan and could not see a carbon dioxide removal system, known as scrubbers.

"That for me is the greatest problem of all of them," the BBC quoted Ramsey as saying.

At the same time, the crew are at risk from hypothermia, where the body gets too cold.

According to Capt Ramsey, if the sub is on the seabed, the water temperature will be about zero degree. If it has also lost electricity, it will not be generating any power and therefore cannot generate heat.

Hypothermia, the lack of oxygen and the build-up of carbon dioxide within the sub mean the crew's ability to make contact with the search and rescue mission, such as by banging on the hull at regular intervals to try and attract attention, will dwindle.

"If they're unconscious, they're not going to be able to do much to help themselves," Ledez told the BBC.

Tour firm OceanGate's Titan submersible was lost about an hour and 45 minutes into its dive to the Titanic's wreckage in the Atlantic on June 18, according to the US Coast Guard.

Tickets cost $250,000 for an eight-day trip including dives to the wreck at a depth of 3,800m.

A search operation is currently underway in an area in the ocean "larger than the state of Connecticut", about 20,000 sq.km. The sub-surface search is now 4 km deep.

Rescue teams from Canada's navy, air force, and coast guard, as well as the New York state air guard are assisting. A French research vessel and Magellan, a British firm that specialises in deep ocean investigations and recovery operations, have also joined the mission.

The Titan submersible is thought to be approximately 1,450 km east and 643 km south of Newfoundland's capital, St John's

According to US Coast Guard estimates, the Titan has roughly 20 hours of oxygen remaining on board.

The five passengers on board are Hamish Harding, 58-year-old British adventurer who has previously been to space and multiple times to the South Pole; British businessman Shahzada Dawood (48) and his son Suleman (19); Paul-Henry Nargeolet (77), a former French Navy diver who has reportedly spent more time at the Titanic wreck than any other explorer and was part of the first expedition to visit it in 1987; and Stockton Rush (61), the chief executive of OceanGate.