The US Coast Guard has recovered debris and evidence from the sea floor near the Titanic wreck site, including what is presumed to be human remains, in the investigation into the implosion of the Titan submersible. The tragedy has raised questions about the safety of private undersea exploration operations. The Coast Guard said the evidence will provide investigators from several international jurisdictions with critical insights into the cause of the disaster. A remotely operated vehicle (ROV) was sent to the site to search the ocean floor for pieces of the submersible. The debris was returned to land Wednesday and unloaded at a Canadian Coast Guard pier. The company that owned and operated the Titan, OceanGate Expeditions, is based in the US. The submersible was registered in the Bahamas and the Titan's mother ship, the Polar Prince, is from Canada.

The Coast Guard has convened a Marine Board of Investigation into the implosion, and the National Transportation Safety Board (NTSB) and Transportation Safety Board of Canada (TSB) are both involved in the investigation. The NTSB has said the Coast Guard has declared the loss of the Titan submersible to be a “major marine casualty” and the Coast Guard is leading the investigation. The International Maritime Organization (IMO), the U.N.'s maritime agency, has voluntary safety guidelines for tourist submersibles. Proposals to strengthen regulations of submersibles will not likely be considered by the IMO until its next Maritime Safety Committee in May 2024.

The vessel was on a voyage to see the wreck of the Titanic when it imploded last week, killing all five people on board. Ocean Gate CEO and pilot Stockton Rush was killed in the implosion along with two members of a prominent Pakistani family, Shahzada Dawood and his son Suleman Dawood; British adventurer Hamish Harding; and Titanic expert Paul-Henri Nargeolet. The Coast Guard is using the investigation to improve safety of submersibles. Analyzing the physical material of recovered debris could reveal important clues about what happened to the Titan, while there could also be electronic data. The operator charged passengers USD250,000 each to participate in the voyage, raising questions about the safety of private undersea exploration operations. The Coast Guard declined to comment on the investigation or the return of debris to shore, while representatives for the NTSB and TSB also declined to comment.