divers are at. this is the pressure going through them. the main air, stand by air. emergency air, diver one, diver two, diver three which is your safety diver. >> reporter: he says the divers will probably be underwater for up to 80 minutes at a time. and then you get in a pressure university. >> this will have things to get in. it's going to be dark inside. a lot of things for divers to get snagged on. >> reporter: then there's the emotional component, right, you know there's going to be bodies down there? >> there's nothing worse than bumping into a bloated dead body in the water. >> reporter: he's sill haunted by the victims he's recovered, especially children. an emotion that divers will have to come to terms with. >> the way you get past it, you say i'm helping the family. >> reporter: he tells us it could take weeks maybe months