Q&A: What are conditions like on board the missing Titanic submarine?

With temperatures on the ocean floor near-freezing and the vessel’s 96 hour oxygen supply running down, occupants are at increasing risk of hyperthermia or suffocation

In this photo released by Action Aviation, the submersible Titan is prepared for a dive into a remote area of the Atlantic Ocean on an expedition to the Titanic on Sunday, June 18. Picture: Action Aviation via AP

Rescue teams are searching for a British billionaire and four others who went missing on a deep-sea vessel near the wreck site of the Titanic ocean liner.

The US Coast Guard is leading the search for the small craft, named Titan, which was reported overdue about 435 miles south of St John’s in Newfoundland, Canada, on Sunday evening.