A company that is moving their operation based on principals would most definatly invite all worthwhile employees along for the ride. That was my personal experiance.
I don't recall, after repurposing a plant, having to get OSHA approval before production began. Just the usuall walkthru at some point afterwords.
We had to use a private company that had their own "OSHA approved" inspector that was retired from OSHA every time the company put in a new machine. This was so the OSHA walkthru was just that and not an inspection.BTW- this was in Ohio.