RAWLINS, Wyo. (AP) — Two of the workers injured in a fire at a Sinclair oil refinery have been released from a Colorado hospital but a third has been transferred to a hospital in Salt Lake City.

The Associated Press reported Tuesday that Tim Bjork (byork) was the most severely injured in the May 8 fire at the refinery. A spokeswoman for Northern Colorado Medical Center in Greeley said he was transferred in stable condition.

The fire occurred May 8 at the Sinclair Oil Corp. refinery, about five miles east of Rawlins. A fourth worker was treated and released from a Rawlins hospital that day.

The vice president of the Sinclair Companies, Clint Ensign, says that the investigation into what caused the fire is nearly complete.

The state recently issued three safety citations against the refinery.