The submersible vessel called Titan disappeared last week while taking five passengers to see the wreckage of the Titanic. The U.S. Coast Guard said on Thursday the vessel imploded, killing all on board.

"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," Vice Adm. Robert Murrett (Ret.), professor of practice of public administration and international affairs, tells Spectrum News. 

Murrett says 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," he says.

Murrett was also interviewed by CBS News, "Debris field found in search area for missing Titanic sub, Coast Guard says," and Fox News, "US Navy detected Titan sub implosion with top secret acoustic system day vessel went missing."