The submersible called the Titan was taking five passengers to see the wreck of the RMS Titanic when the machine lost contact shortly into its voyage earlier this week. The U.S. Coast Guard said on Thursday the machine imploded.

“When accidents like this happen, they shouldn't be that much of a surprise to people just because of how dangerous these kind of environments could be," said Retired Vice Admiral Robert Murrett. He is a professor of practice with Syracuse University.

He said he was in the United States Navy for 34 years before coming to Syracuse.

“I was indirectly involved in a couple of incidents that had to do with loss of one Russian or one Soviet submarine," Murrett said.

Murrett said the Titan, operated by Oceangate Expeditions, was not built with the same materials as other submersibles.

“It was unconventional, kind of cutting-edge industry use of carbon fiber and so forth. It also did not have the kind of redundant systems that we're accustomed to having from safety purposes and vehicles that are typically used, ones that are manned for those kinds of purposes," Murrett said.

As he understands it, he said the submersible did not go through typical certifications.

“I think the bigger consideration here is that it's a reminder of how dangerous operating at water depths, such as, 12,000 feet, for goodness sakes, are," said Murrett.

If found, Murrett said the first step is for search crews to identify the sub, retrieve if possible, and see what happened.

Murrett commends the work of the United States Coast Guard and international partners for their response and cooperation in the search.