An adventurer who used to consult with OceanGate, the company behind the missing submersible, left the firm because he thought its founder was over-promising and rushing things

• Rob McCallum told Bloomberg in 2017 he was worried OceanGate CEO Stockton Rush was rushing things.
• McCallum, an explorer, said he thought nothing should be left up to chance when exploring the ocean.

A marine adventurer who used to consult for OceanGate, the maker of the Titan tourist submersible that went missing on Sunday, left the company partly over his worries that its CEO was over-promising and rushing things.

Rob McCallum, the founder of the expedition service provider EYOS Expeditions, consulted for OceanGate when the company had just started in 2009, per a 2017 Bloomberg feature on Rush and OceanGate.

"I know Stockton well and think the world needs more Stocktons prepared to take a chance," McCallum told Bloomberg.

"But he's a full-speed-ahead, damn-the-torpedoes kind of guy, and in the submersible industry, extreme depth is all about precision and control. Nothing can be left to chance," he added.

McCallum told Insider that he still stands by his assessment of Rush and OceanGate, adding that Rush's working style and equipment could have caused the submersible to go missing.

McCallum, who says he is familiar with the equipment used in the Titan submersible, also told Insider he did not think that the submersible was safe for use.

McCallum ended up going to the Titanic shipwreck back in August 2019 with explorer Victor Vescovo, per Good Morning America. McCallum's crew used the DSSV Limiting Factor, a two-person submersible made by Triton Submarines, per the Seattle-based news site GeekWire.

"I would never dive in an unclassed/uncertified sub," McCallum told Insider.

OceanGate did not immediately respond to a request for comment from Insider sent outside regular business hours.

Rush, who founded OceanGate, is one of the five passengers aboard the missing Titan submersible. His previous remarks on submersible safety have resurfaced since the Titan submersible went missing during a dive expedition to the Titanic shipwreck.

For one, Rush told the Smithsonian Magazine in June 2019 that he thought the regulations had kept the commercial submarine industry "obscenely safe," but were impeding its progress.

Unlike other seafaring vessels, the Titan submersible was not "classed," a standard practice that ensures that vessels are designed to acceptable standards. OceanGate said in February 2019 it did not do so because going through this process meant the Titan submersible would have had to undergo a "multi-year approval cycle."

Rescuers are now racing against time to locate the submersible, which could run out of oxygen by Thursday afternoon.

A unified command comprising the US Coast Guard, US Navy, Canadian Coast Guard, and OceanGate Expeditions has been formed to continue the ongoing search effort, the US Coast Guard said in a statement on Tuesday.