The National Transportation Safety Board has released its final report on the cause of the Titan submersible's catastrophic implosion, blaming the company that operated it for shoddy design and failure to test the vessel before its fateful trip in June 2023.

The 22-foot submersible made of carbon fiber imploded on June 18, 2023, on its dive to visit the Titanic wreckage site, killing all five people on board, because of an "inadequate engineering process" and damage to the vessel that went unnoticed, the NTSB's 87-page report released on Oct. 15 found.

The report comes after the Coast Guard concluded in August that a combination of factors, including inadequate design, improper maintenance and a toxic workplace culture at OceanGate, all contributed to the disaster. The Coast Guard report found that had he lived, OceanGate's CEO may have been criminally charged.

The five killed were OceanGate's founder and CEO Stockton Rush, British billionaire Hamish Harding, French maritime expert Paul-Henri Nargeolet, Pakistani businessman Shahzada Dawood and his 19-year-old son, Suleman Dawood.

Titan's disappearance launched a frenzied multinational search that stretched for days before the sub's debris field was spotted at the ocean bottom.

Sub was damaged, but company continued dives anyway: NTSB

Titan was damaged in an earlier dive that weakened its pressure vessel, which was responsible for maintaining the atmospheric air pressure for human occupants, the NTSB found in its investigation.

The damage happened during dive 80, on July 15, 2022. As Titan resurfaced from its over 12,000-foot dive to the Titanic wreckage that day, people on board heard a "loud bang" and were told the vessel's hull had shifted in its metal cradle. According to the report, Rush wanted to continue dives even after hearing the bang. Titan did three more dives on that year's expedition.

The investigation found that the bang was a result of delamination between the layers of the material that made up the pressure hull. That damage was not immediately fatal; Titan was able to complete more dives to Titanic's depth. But further damage that could have been caused by storing the vessel uncovered outdoors and subjecting it to freezing temperatures and other factors. That further weakened the pressure hull, leaving it unable to survive another trip to Titanic's depths, the report concluded.

The damage eventually led to a localized "buckling failure," which caused the implosion at a depth of 10,032 feet.

"OceanGate’s analysis of Titan pressure vessel real-time monitoring data was flawed, so the company was unaware that the Titan was damaged and needed to be immediately removed from service," the report found.

The carbon fiber composite pressure vessel, regarded as largely untested in the industry at such depths, "failed to meet necessary strength and durability requirements" to withstand trips to Titanic, the NTSB said.

Rescue was not possible for Titan passengers

The NTSB said OceanGate should have had emergency response assets standing by to respond to a crisis, which would have cut down on the time and money spent to locate Titan after its support crew realized it was missing. But "a rescue was not possible in this case," the agency said.

The Coast Guard's earlier report found that all five passengers died immediately when the submersible imploded. The implosion exposed its occupants to 4,930 pounds per square inch of water pressure, killing them instantly, the report found.

When Titan was first reported to authorities as in distress, a multinational search was launched for signs the sub may have surfaced with its occupants still alive but possibly running out of oxygen. It wasn't until the discovery of the debris field at the bottom of the ocean on June 22, 2023, that investigators conclusively determined the vessel imploded.

Regulations on submersibles were 'insufficient,' report finds

Insufficient U.S. and international regulatory standards for "pressure vessels for human occupancy," or PVHOs, were a contributing factor in the implosion, the report said. The voluntary guidance and regulations in place were "insufficient to ensure OceanGate adhered to established industry standards," the NTSB said.

The agency recommended the U.S. Coast Guard change its PVHO regulations and urged international standards that would ensure "consistency in design, construction, and operation requirements."

For years before the implosion, OceanGate "leveraged intimidation tactics, allowances for scientific operations, and the company’s favorable reputation to evade regulatory scrutiny," the Coast Guard report released earlier this year also found.

Titan was not registered, certified or inspected by any recognized organization, the Coast Guard said.

This article originally appeared on USA TODAY: Titan submersible imploded because of poor design, insufficient testing, NTSB report finds

Reporting by Jeanine Santucci, USA TODAY / USA TODAY

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