I hired on as an intern which only involved one interview, mostly of situational questions. Nothing too hard, just asking to describe what you would do in certain situations. They want to hear how you put safety first. This is not the typical approach for interviews and this was the process years ago - I'm sure it has changed.

First was a phone screening interview for 30 odd minutes. The followup interview was a standard behavioral based interview that was about an hour to an hour and a half. After the offer, then I had to do drug testing and background checks to get fully cleared. The whole process was about a month to a month and a half.