The director of marine operations at OceanGate, the company whose submersible went missing Sunday on an expedition to the Titanic in the North Atlantic, was fired after raising concerns about its first-of-a-kind carbon fiber hull and other systems before its maiden voyage, according to a filing in a 2018 lawsuit first reported by Insider and New Republic.

David Lochridge was terminated in January 2018 after presenting a scathing quality control report on the vessel to OceanGate’s senior management, including founder and CEO Stockton Rush, who is on board the missing vessel.

According to a court filing by Lochridge, the preamble to his report read: “Now is the time to properly address items that may pose a safety risk to personnel. Verbal communication of the key items I have addressed in my attached document have been dismissed on several occasions, so I feel now I must make this report so there is an official record in place.”

The report detailed “numerous issues that posed serious safety concerns,” according to the filing. These included Lochridge’s worry that “visible flaws” in the carbon fiber supplied to OceanGate raised the risk of small flaws expanding into larger tears during “pressure cycling.” These are the huge pressure changes that the submersible would experience as it made its way and from the deep ocean floor. He noted that a previously tested scale model of the hull had “prevalent flaws.”

Carbon fiber composites can be stronger and lighter than steel, making a submersible naturally buoyant. But they can also be prone to sudden failure under stress. The hull that Lochridge was writing about was made by Spencer Composites, the only company to have previously made a carbon fiber hull for a manned submersible. (That submersible was commissioned by explorer Steve Fossett for a record-breaking dive, but he died in a light aircraft crash before it could be used.)

Lochridge’s recommendation was that non-destructive testing of the Titan’s hull was necessary to ensure a “solid and safe product.” The filing states that Lochridge was told that such testing was impossible, and that OceanGate would instead rely on its much touted acoustic monitoring system.

The company claims this technology, developed in-house, uses acoustic sensors to listen for the tell-tale sounds of carbon fibers in the hull deteriorating to provide “early warning detection for the pilot with enough time to arrest the descent and safely return to surface.”

Lochridge, however, worried in the lawsuit that the system would not reveal flaws until the vessel was descending, and then might only provide “milliseconds” of warning before a catastrophic implosion.

Russell McDuff, a veteran oceanographer and chairman of OceanGate’s scientific and research foundation for three years, noted that contact with the Titan was lost on Sunday after only an hour and 45 minutes. “This suggests to me that they might have still been in the water column, descending to the Titanic,” told TechCrunch in a phone interview.

Lochridge also strongly encouraged OceanGate to have a classification agency, such as the American Bureau of Shipping, inspect and certify the Titan.

A day after filing his report, Lochridge was summoned to a meeting with Rush and company’s human resources, engineering and operations directors. There, the filing states, he was also informed that the manufacturer of the Titan’s forward viewport would only certify it to a depth of 1,300 meters due to OceanGate’s experimental design. The filing states that OceanGate refused to pay for the manufacturer to build a viewport that would meet the Titan’s intended depth of 4,000 meters. The Titanic lies about 3,800 meters below the surface.

The filing also claims that hazardous flammable materials were being used within the submersible.

At the end of the meeting, after saying that he would not authorize any manned tests of Titan without a scan of the hull, Lochridge was fired and escorted from the building.

Lochridge, who claimed he was discharged in retaliation for being a whistleblower, made his filing after OceanGate sued him in federal court in Seattle that June. OceanGate has accused him of sharing confidential information with two individuals, as well as with the Occupational Safety and Health Administration (OSHA). In the lawsuit, OceanGate characterized Lochridge’s report as false, and  accused him of committing fraud by manufacturing a reason to be fired.

The lawsuit was settled in November 2018. Neither OceanGate nor Lochridge responded to requests for comment. OSHA could not immediately provide details of the alleged report. A routine OSHA inspection of OceanGate in 2021 found only three minor workplace safety violations resulting in no financial penalties.

A few months after Lochridge’s dismissal, the company published a blog post that laid out its reasons for not having Titan certified by the American Bureau of Shipping or a similar organization.

“The vast majority of marine (and aviation) accidents are a result of operator error, not mechanical failure,” it reads. “As a result, simply focusing on classing the vessel does not address the operational risks. Maintaining high-level operational safety requires constant, committed effort and a focused corporate culture – two things that OceanGate takes very seriously and that are not assessed during classification.”

In 2019, Rush gave an interview to Smithsonian magazine, in which he said: “There hasn’t been an injury in the commercial sub industry in over 35 years. It’s obscenely safe, because they have all these regulations. But it also hasn’t innovated or grown—because they have all these regulations.”

Following Lochridge’s departure, the Titan was tested safely on increasingly deep dives, including to 4,000 meters in the Bahamas. However, it seems one of Lochridge’s concerns would soon be borne out. In January 2020, Rush gave an interview to GeekWire in which he admitted that the Titan’s hull “showed signs of cyclic fatigue.” Because of this, the hull’s depth rating had been reduced to 3,000 meters. “Not enough to get to the Titanic,” Rush said.

During 2020 and 2021, the Titan’s hull was either repaired or rebuilt by two Washington state companies, Electroimpact and Janicki Industries, that largely work in aerospace. In late 2021, the Titan made its first trip down to the wreck of the Titanic.

Spencer Composites says that the Titan was not using its carbon fiber hull on Sunday’s dive. Presumably apart from the hull work, one source familiar with the company told TechCrunch that not much with Titan had changed at all since 2018.

At the time of publication, the Titan remains missing, with Rush, French diver Paul-Henri Nargeolet, British billionaire Hamish Harding, Pakistani businessman Shahzada Dawood and his son reportedly on board. A massive search and rescue operation is underway.

“They’re doing everything that they logically can,” McDuff said. “But I’m a little pessimistic because of the amount of time that’s gone by.”