A truck became fully engulfed in flames Wednesday after rolling on its side on New Mexico Highway 173, southeast of Aztec, according to the San Juan County Sheriff’s Office.

Lt. Al Jamison said a man driving a Ford F-250 was headed to work Wednesday morning when he swerved to miss a deer, causing the truck to roll on its side.

The driver was uninjured and able to self-extricate from the vehicle, Jamison said.

But as a tow truck was loading the F-250, which was leaking a significant amount of fuel, it caught fire and became fully engulfed in flames. Authorities are unsure what sparked the fire, Jamison said.

“I’ve never seen that in 18 years,” he said. “It was new for me.”

Highway 173 near mile marker 5 was closed for about an hour, Jamison said.