PORTLAND, Maine (AP) -- Faulty engineering led to the implosion of an experimental submersible that killed five people on the way to the wreck of the Titanic, the National Transportation Safety Board concluded in a report Wednesday.

The NTSB made the statement in its final report on the hull failure and implosion of the Titan submersible in June 2023. Everyone on board the submersible died instantly in the North Atlantic when Titan suffered a catastrophic implosion as it descended to the wreck.

The NTSB report states that the faulty engineering of the Titan "resulted in the construction of a carbon fiber composite pressure vessel that contained multiple anomalies and failed to meet necessary strength and durability requirements." It also stated that OceanGate, the owner of the Titan, failed to adequately test the Titan and was unaware of its true durability.

The report also said the wreckage of the Titan likely would have been found sooner had OceanGate followed standard guidance for emergency response, and that would have saved "time and resources even though a rescue was not possible in this case."

The NTSB report dovetails with a Coast Guard report released in August that described the Titan implosion as preventable. The Coast Guard determined that safety procedures at OceanGate, a private company based in Washington state, were "critically flawed" and found "glaring disparities" between safety protocols and actual practices.

OceanGate suspended operations in July 2023 and wound down. A spokesperson for the company declined to comment on Wednesday.

In August, after the Coast Guard report was released, a company spokesperson offered condolences to the families of those who died.

The Titan's implosion killed OceanGate CEO Stockton Rush and led to lawsuits and calls for tighter regulation of private deep sea expeditions. The implosion also killed French underwater explorer Paul-Henri Nargeolet, known as "Mr. Titanic"; British adventurer Hamish Harding; and two members of a prominent Pakistani family, Shahzada Dawood and his son Suleman Dawood.

The NTSB report recommends the Coast Guard commission a panel of experts to study submersibles and other pressure vehicles for human occupancy. It also recommends that the Coast Guard implement regulations for the vehicles that are informed by that study. The report states that current regulations for small passenger vessels "enabled OceanGate's operation of the Titan in an unsafe manner."

The report also called on the Coast Guard to "disseminate findings of the study to the industry," which has grown in recent years as privately financed exploration has grown.

The company was aware of the possibility of Coast Guard regulations prior to the implosion. In describing OceanGate's corporate culture, the report quotes an operations technician who quit the company after expressing concern about calling paying passengers "mission specialists." The company's CEO responded that "if the Coast Guard became a problem ... he would buy himself a congressman and make it go away," the technician said, according to the report.

The vessel had been making voyages to the Titanic site since 2021. Its final dive came on the morning of June 18, 2023. The submersible lost contact with its support vessel about two hours later and was reported overdue that afternoon. Ships, planes and equipment were rushed to the scene about 435 miles (700 kilometers) south of St. John's, Newfoundland.

A multiday search for survivors off Canada made international headlines. It soon became clear there would be no survivors, and the Coast Guard and other authorities began lengthy investigations into what had happened.

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Ramer reported from Concord, New Hampshire.