Sinclair Oil is offering a $25,000 reward for information about an apparent sabotage attempt at its refinery near Rawlins.
Workers discovered damage to a number of valves on Oct. 18 after noticing strange feedback from instruments on a hydro-cracking unit.
A company spokesman says the company concluded the damage was intentional but wouldn't comment on whether there were signs of a break-in.
Sinclair Police Chief Jeff Sanders confirmed Wednesday that his department is investigating.
The refinery has had several accidents and releases over the past several years.