Hearing to explore what caused Titan submersible disaster

US authorities have kicked off a two-week investigation into how the Titan submersible imploded deep in the ocean last summer, killing all five of its passengers.

The public hearing will look at what led to the destruction of the deep-sea vessel that was en route to the wreck of the Titanic when it imploded less than two hours into its descent.

Investigators with the US Coast Guard have gathered evidence behind the scenes for 15 months to learn what might have caused the June 2023 incident.

The hearing that began Monday "aims to uncover the facts... and develop recommendations to prevent similar tragedies in the future", the agency says.

Unanswered questions over the Titan's ill-fated dive have fuelled a lingering debate over safety and regulation in the world of private undersea exploration.

OceanGate, the Washington-state based manufacturer behind the craft, has faced questions over its design choices, its safety record and its adherence to regulations.

Experts in marine safety and undersea exploration, as well as former employees of OceanGate, are expected to testify over the next fortnight before the Coast Guard's Marine Board of Investigations (MBI).

MBI is the highest available level of inquiry into US marine casualties and convenes roughly one hearing per year, its chairman told reporters on Sunday.

"Out of thousands of investigations conducted, less than one rise to this level,” Jason Neubauer said.

The board, which is made up of top Coast Guard and National Transportation Safety Board (NTSB) officials, has the authority to recommend civil penalties or make referrals for criminal prosecution by the US Department of Justice.

An international search and rescue mission unfolded after the submersible lost contact with its mother ship, the Polar Prince, on the morning of 18 June 2023 and never resurfaced.

On board were OceanGate's founder and CEO Stockton Rush, British explorer Hamish Harding, veteran French diver Paul Henri Nargeolet, the British-Pakistani businessman Shahzada Dawood and his 19-year-old son Suleman.

Debris containing their "presumed human remains" was recovered in ensuing days as authorities concluded Titan had suffered a "catastrophic implosion", collapsing inward under immense pressure.

OceanGate suspended all exploration and commercial operations following the incident.

The company currently has no full-time staff but is cooperating with investigators and will be represented by an attorney at the MBI hearings, it said in a statement to the Associated Press.

“There are no words to ease the loss endured by the families impacted by this devastating incident, but we hope that this hearing will help shed light on the cause of the tragedy,” the statement added.

The fortnight of public inquiries in North Charleston, South Carolina will delve into "all aspects of the loss of the Titan", including "pre-accident historical events, regulatory compliance, crewmember duties and qualifications, mechanical and structural systems, emergency response and the submersible industry".

The MBI is expected to hear testimony from as many as 10 current or former OceanGate employees, including the company's co-founder Guillermo Sohnlein.

Other anticipated witnesses include specialists in deep-sea exploration, industry regulators, search and rescue experts, and engineers from Nasa and Boeing.

Additional hearings may yet be scheduled in a probe that was initially slated to last about a year.

Once the investigation wraps up, both the Coast Guard and the NTSB will produce reports containing their independent analysis.