I originally applied for a similar role (process control technologist). After a phone interview and on-site interview (the on-site consisted of 1 hour of STAR questions and a tour of the refinery), I was quickly offered the role, but did not accept. Getting a better description of the job, I expressed that I was only interested in an engineering role rather than the technologist role and we agreed to keep in contact in case a PCE role opened. A few months later, I was contacted with news that a PCE role had opened and that I was being considered. It was very encouraging that HR followed through and got in touch with me. Unfortunately, from this point the process took exceedingly long. Between going on site again (to speak to the exact same people), getting internal "approval" for the job requisition, and background screening, it was close to 4 months before I was confident I had the position. This put a lot of strain on me as I was still continuing in my current employment. When I finally did get the offer, I was very happy with it and accepted. The site HR was flexible with start date and helpful with keeping me up to speed during the (long) process.