The Titan submersible went missing off the coast of Newfoundland, Canada, on June 18 on voyage to the Titanic shipwreck in the depths of the Atlantic Ocean.

The five-person crew, which comprised British billionaire Hamish Harding; Pakistani businessman Shahzada Dawood and his 19-year-old son, Suleman; French explorer Paul-Henri Nargeolet; and Stockton Rush, CEO of OceanGate, had only a four-day supply of emergency oxygen on the submersible when it set off to find the wreckage of the Titanic.

Four days after the crew set off on their voyage—and as a frantic search for the sub wound down—the U.S. Coast Guard announced that the Titan had imploded on its journey, which would have instantly killed all five of its passengers.

‘It’s a lemon’

Over the weekend, The New Yorker printed the content of old email conversations between some of the company’s staff, alongside interviews with former OceanGate employees.  

David Lochridge, the firm’s former director of marine operations and chief submersible pilot, sued OceanGate in 2018 after allegedly being fired for raising concerns about the Titan’s capacity to safely dive to the depths at which the Titanic ruins lie.

Shortly after his departure from the firm, Rob McCallum, who was involved in the development of OceanGate’s Titanic expeditions, emailed Lochridge to “get a handle on exactly how bad things are.”

“I do get reports, but I don’t know if they are accurate,” McCallum wrote, according to The New Yorker.

McCallum had served as the expedition lead for the Titan, but eventually took himself off of the project after being warned by experts that a catastrophic operational failure was “certain” and discovering that OceanGate CEO Rush was refusing to have the sub independently classed as safe.  

“I think you are going to [be] even more taken aback when I tell you what’s happening,” Lochridge reportedly told him. “That sub is not safe to dive.”

“Do you think the sub could be made safe to dive, or is it a complete lemon?” McCallum asked in his next email, adding that everyone in the submersible industry was “watching and waiting and quietly sh***ing their pants.”

“It’s a lemon,” Lochridge replied, to which McCallum responded: “Oh dear. Oh dear, oh dear.”

Lochridge was a qualified submarine pilot and underwater inspector who was trained to “recognize flaws and points of failure in subsea equipment,” according to his 2018 lawsuit, which was settled out of court. He said in legal filings that he had repeatedly warned the submersible was not being built or tested to suitable safety standards, potentially putting paying passengers “milliseconds from implosion.”

“I would consider myself pretty ballsy when it comes to doing things that are dangerous, but that sub is an accident waiting to happen,” Lochridge said in an email to McCallum two weeks after being fired, according to The New Yorker. “There’s no way on earth you could have paid me to dive the thing.”

He added: “I don’t want to be seen as a tattletale, but I’m so worried [Rush] kills himself and others in the quest to boost his ego.”

A spokesperson for OceanGate was not immediately available when contacted by Fortune.

OceanGate CEO took warnings ‘as a serious personal insult’

Lochridge wasn’t the only person to have noticed major shortcomings relating to the safety of the Titan.

British millionaire Chris Brown recently revealed he had pulled out of the doomed expedition after paying a deposit as he was concerned OceanGate had “cut too many corners.”

Meanwhile, investor Jay Bloom and his 20-year-old son told CNN that they’d given up their seats on the Titan just weeks before it met its disastrous end. The pair said they’d decided not to join the voyage owing to concerns about how safe the vessel was.

Filmmaker James Cameron—who famously directed the 1997 blockbuster Titanic and has embarked on 33 deep-sea dives to the ship’s wreckage—blamed the accident on the Titan’s “completely inappropriate” design, labeling it “a horrible idea.”

The New Yorker reported on Saturday that following his conversation with Lochridge, McCallum attempted to persuade OceanGate CEO Rush to reconsider his approach to innovating the industry.

“You are wanting to use a prototype un-classed technology in a very hostile place,” he reportedly told his boss in an email. “As much as I appreciate entrepreneurship and innovation, you are potentially putting an entire industry at risk.”

Four days later, Rush reportedly replied to McCallum’s emailed concerns. Rush told him he understood that his practices flew “in the face of the submersible orthodoxy, but that is the nature of innovation.” Rush said he had “grown tired of industry players who try to use a safety argument to stop innovation and new entrants from entering their small existing market.”

“We have heard the baseless cries of ‘You are going to kill someone’ way too often,” he said. “I take this as a serious personal insult.”

McCallum continued to challenge Rush, telling him: “In your race to Titanic you are mirroring that famous catch cry ‘She is unsinkable.’”

Rush asked McCallum if he would work for him, and threatened him with a lawsuit when he said no, The New Yorker reported.

According to the publication, Rush asked OceanGate’s director of finance and administration to take on the newly vacant chief submersible pilot role.

She told the magazine: “It freaked me out that he would want me to be head pilot, since my background is in accounting.”

She added that many of the company’s engineers were in their late teens and early twenties, and were making $15 an hour. Without Lochridge around, she decided to quit.

“I could not work for Stockton,” she said. “I did not trust him.”

Rush had publicly spoken about his disregard for rules in his mission to be “remembered as an innovator.”

“I think it was [American Gen. Douglas] MacArthur that said, ‘You’re remembered for the rules you break,’” he noted in a 2021 interview.

“I have broken some rules to make this,” he conceded. “I think I’ve broken them with logic and good engineering behind me. The carbon fiber and titanium—there is a rule that you don’t do that. Well, I did.”