The Defense Department is refusing to say whether it notified the families of passengers on the Titan submersible after it detected a possible implosion sound immediately after the vessel lost contact with its mother ship.
In a statement to Fox News Digital, the US Coast Guard, which led the Pentagon’s unified command for the incident, said it had contacted the families when it became aware of the situation and notify once remains were found days later. However, officials said Thursday that after finding the wreckage, the US Navy had detected an implosion sound almost immediately after the Titan lost contact on June 18.
“The Unified Command contacted the families as soon as we became aware of the incident and have maintained contact throughout our response,” Coast Guard spokeswoman Anne McGoldrick told Fox News Digital.
“As has been our approach throughout this search and is the policy of the Search and Rescue community, officials will always notify Next of Kin and make every effort to involve the family before information is released to the public ” McGoldrick said. “The families were notified immediately as soon as the debris was identified.”
CREW OVERLOADED IN ‘CATASTROPHIC IMPLOSION’: TIMELINE OF MISSION TO FIND OCEANGATE’S MISSING SUBMARINE TITANIC

Inset, from left: Suleman Dawood, Shahzada Dawood, Stockton Rush, Paul-Henry Nargeolet and Hamish Harding were aboard the OceanGate Titan submersible. (Engro Corp. | Reuters/Shannon Stapleton | @OceanGateExped/Twitter | Felix Kunze/Blue Origin via AP | Ocean Gate/Handout/Anadolu Agency via Getty Images)
It remains unclear whether US officials leading the response to the incident ever notified the families on June 18, or in the four days that followed, that an explosion likely occurred. The Coast Guard, Navy and Defense Department did not respond to follow-up questions from Fox News Digital.
On June 18, the five passengers of the Titan, a submersible operated by the exploration company OceanGate, boarded the ship to dive to view the Titanic about 900 miles east of Massachusetts. The passengers were OceanGate CEO Stockton Rush; British businessman Hamish Harding; Shahzada and Suleman Dawood, Pakistani father and son; and Paul-Henry Nargeolet, former French Navy officer and Titanic expert.
MISSING TITANIC SUB ‘didn’t do well,’ says veteran explorer who picked up documentary over safety concerns
Approximately one hour and 45 minutes into the dive, the Titan lost contact with the mothership from which it had exited. In the days that followed, the Coast Guard led a comprehensive search and rescue effort involving the private sector and Canadian entities, and regularly updated the public on the estimated amount of oxygen left aboard the Titan.
On Wednesday, the Coast Guard said it had heard “underwater noises” in the search area, which some believed indicated the Titan was trapped below the surface with its passengers trapped.

Rear Admiral John Mauger speaks to reporters Thursday in Boston. (REUTERS/Brian Snyder)
But on Thursday, the Coast Guard announced it had discovered a “debris field” in the area where the submersible was believed to have gone missing. Officials then told reporters during a news conference that the debris was “consistent with catastrophic loss of pressure chamber,” suggesting that Titan had imploded instantaneously when it lost contact days earlier.
“After this determination, we notified the families immediately,” said Coast Guard Rear Adm. John Mauger. “On behalf of the United States Coast Guard and the entire unified command, I offer my deepest condolences to the families.”
CLICK HERE TO GET THE FOX NEWS APP
Shortly after Mauger’s comments, however, a Navy official confirmed to Fox News Digital that a top-secret acoustic detection system heard sounds consistent with an implosion near the site of the Titanic around the time the Titan lost the contact on June 18.
“While not definitive, this information was immediately shared with the incident commander to assist with the ongoing search and rescue mission,” a Navy official told Fox News Digital.
Fox News Digital reporters Bradford Betz, Lucas Tomlinson, Michael Ruiz, Anders Hagstrom and Chris Pandolfo contributed to this report.