Titan sub disaster should make sea-exploration industry rethink taking tourists to such remote locations, says expert

• The search is on for the Titan submersible that went missing en route to the wreck of the Titanic.
• The sea-exploration industry must now reassess taking passengers so remote and deep, an expert said.

The sea-exploration industry needs to closely examine itself and reassess bringing passengers to such remote locations, a leading expert said after a submersible carrying five people to the Titanic wreckage went missing.

David Mearns, a marine biologist and oceanographer, told the BBC that amid the desperate search for the Titan sub and its crew: "I certainly feel that now an investigation obviously should happen."

"This sort of thing we cannot allow to happen, and my industry needs to look in on itself and reflect on bringing passengers to such remote locations and such great depths because if things go wrong, there are very, very few options to make a recovery," he said.

Mearns, nicknamed the "shipwreck hunter" has discovered a number of sunken ships, including the deepest shipwreck ever found, the SS Rio Grande, discovered three-and-a-half miles below the surface of the Atlantic Ocean in 1996, the BBC reported.

The latest catastrophe has raised fresh questions about the risks involved in deep-sea exploration, especially when it comes to bringing passengers on trips.

The Titan submersible, operated by OceanGate Expeditions, lost contact with its mothership less than two hours into its trip on Sunday. Those on board include a 58-year-old British billionaire, a 48-year-old British-Pakistani businessman and his 19-year-old son, and a 77-year-old French navy captain and veteran deep-sea diver known as "Mr. Titanic."

The vessel was trying to reach the wreckage of the Titanic, which is around 13,000 feet below sea level.

A desperate search began for the Titan on Sunday, with the oxygen on board the submersible expected to run out on Thursday morning.

It is not clear if the vessel is still intact, if it is floating on top of the ocean, or if it is down with the Titanic wreckage.

The depth of the Titanic is one of the reasons the search is so complicated, with most search-and-rescue equipment useless at that depth.

The incident has also raised questions about the safety of the Titan submersible, with experts saying the company didn't follow proper safety rules and managed to do so by operating in international waters.

A CBS journalist who went on the submersible least year was made sign a waiver that said the Titan was an "experimental vessel" that had not been "approved or certified by any regulatory body."

Mearns told the BBC that the Titan not being safety certified was a "cause for concern," adding: "Would I choose a vessel without a classification? It's not even allowed. I think that answers that."