In an interview with CBS Sunday Morning last year, Rush discussed his company, and while stressing that there were serious risks involved, said that the trips were safe.
"What I worry about most are things that will stop me from being able to get to the surface," he said.
"Overhangs, fish nets, entanglement hazards. And, that's just a technique, piloting technique. It's pretty clear - if it's an overhang, don't go under it. If there is a net, don't go near it. So, you can avoid those if you are just slow and steady."