OK, I have been wondering about this for a while. I know a FF at the refinery. It appears that it may be a trunked EDACS system. The license is incorrect. I found the license in this thread already (WNWE657). I noticed that the conversation jumped frequencies between the repeater frequencies listed. I also noticed the EDACS beeps after a person stopped transmitting. I wasn't able to find an EDACS CC on any of the repeater frequencies in that license, however.
I searched through 851.0125-868.9875, and low and behold I found an EDACS CC. The control channel right now is 859.81250. I ran a search for that frequency, and WQJF568 came up. It is a conventional license, but it is a trunked system. Notes of that license, "RADIOS WILL BE USED IN OPERATION OF OIL REFINERY." The FF I know said his radio says "Trunked Safety."
So I believe the licenses are related.
Jacob