U.S. Senate candidate Tommy Tuberville’s campaign bus caught fire in northeast Alabama on Wednesday night during a test drive.

The Senate candidate was not aboard the bus and the only person on board was a driver who was uninjured, according to a Facebook post from the DeKalb County Sheriff’s Office.

The Facebook post showed a recreational vehicle ablaze and announced the closure of an Interstate 59 lane due to the incident. 

The bus was traveling near Hammondville, about 10 miles from the Georgia state line, when it caught on fire. Paul Shashy, Tuberville’s campaign manager, told AL.com the fire began during a test drive after maintenance. 

“Coach Tuberville’s candidacy has obviously caught fire with voters...and our bus has, too,” Shashy said. “We are thankful that no one was hurt in the incident and for the remarkable first responders who assisted immediately.”

Tyler Pruett, a spokesman for the DeKalb County sheriff, told AL.com that the cause of the fire is unknown, but “we don’t suspect any kind of foul play.”

Tuberville, a former Auburn football coach, is competing in a July 14 runoff campaign against former Attorney General Jeff Sessions for the Republican nomination. The former attorney general is seeking to get back his seat that he held for 30 years.

The winner of the nomination will face Sen. Doug Jones (D-Ala.) in November. Jones won his seat in a special election after President Trump tapped Sessions to become attorney general.