Wood River, IL (KTRS) Investigators are working to determine what caused an explosion at a metro-east oil refinery.

At around 4:30 PM Sunday, an explosion in a process operation unit injured an employee at Wood River Oil Refinery in Roxana. The refineries’ firefighters were able to extinguish the blaze, and the employee was transported to an area hospital with minor injuries. All employees and contractors were accounted for, and the facility has returned to normal operations.

The plant processes over 300,000 barrels of crude oil per day.