The two-year investigation has been published, citing key findings, contributing factors to the casualty and a recommended regulatory framework.

Coast Guard investigators say the event was "a preventable tragedy," with OceanGate's failure to follow safety and testing protocols being the main reason the sub imploded.

A lengthy report released by the US Coast Guard Tuesday identified glaring issues with the Titan submersible and the company that ran it, a little more than two years after five people were killed when the deep-sea craft imploded on its way to the Titanic wreckage.