The missing Titanic tourist submarine was not approved by any regulatory body - meaning all passengers had to sign a waiver before the $250,000 (£195,000) trip.
CBS Sunday Morning reporter David Pogue, who encountered problems himself on a previous OceanGate trip, claimed that the submarine appeared to be "improvised from off-the-shelf parts".
He also recalled a waiver that read: "This experimental vessel has not been approved or certified by any regulatory body, and could result in physical injury, emotional trauma, or death."
Rescue teams are in a race against time to find a submersible tourist vessel which went missing during a voyage to the Titanic shipwreck off the coast of Canada, with a British billionaire among five people aboard.
There may be as little as 58 hours of emergency oxygen left aboard the submersible, which lost communication with tour operators on Sunday while about 435 miles south of St John’s, Newfoundland.
OceanGate Expeditions said its focus was on those aboard the vessel and their families.
“We are deeply thankful for the extensive assistance we have received from several government agencies and deep sea companies in our efforts to re-establish contact with the submersible,” the company said in a statement.
“We are working toward the safe return of the crew members.”
Unlike submarines that leave and return to port under their own power, submersibles require a ship to launch and recover them.
Rear Admiral John W Mauger of the US Coast Guard said they are doing “everything” they can to find the submersible, saying it has one pilot and four mission specialists aboard with up to 96 hours of emergency oxygen on board.
“We anticipate that there’s somewhere between 70 to the full 96 hours at this point,” he said on Monday. “It is a remote area and a challenge, but we are deploying all available assets.”
He said additional resources would arrive in the coming days.
Private plane firm Action Aviation said its British chairman Hamish Harding is one of the mission specialists on the five-person OceanGate Expeditions vessel.
UK-based businessman Shahzada Dawood and his son Sulaiman Dawood have also been named in a family statement as two of the other people on board the “very tiny” craft.
French submersible pilot Paul-Henry Nargeolet and chief executive and founder of OceanGate Expeditions Stockton Rush are also on the vessel, according to reports.
A statement from the Dawood Family, obtained by CNN, said: “As of now, contact has been lost with their submersible craft and there is limited information available.
“We are very grateful for the concern being shown by our colleagues and friends and would like to request everyone to pray for their safety while granting the family privacy at this time. The family is well looked after and are praying to Allah for the safe return of their family members.”
