BEND, Ore. -- A semi-truck load caught fire East of Bend late Wednesday night, causing a six-hour closure on Highway 20E.

Oregon State Police/kgw.com photo

The fire burned hot and long on the semi-truck.

It happened just after 10 p.m., about sixty miles east of Bend near Hampton. Investigators said they don’t know exactly how the truck’s load of recycled cardboard caught fire, but it was nearly impossible to put out.

The driver, Michael Asbury, 30, was able to separate the trailer before the flames caused any damage to the truck. Then, crews with the Oregon Department of Transportation used a bulldozer to move the still-burning trailer to the side of the highway.

“The load continues to burn on the shoulder as ODOT and BLM monitor its status,” Lt. Gregg Hastings with Oregon State Police said early Thurday morning.

The truck was hauling cardboard from Idaho to Springfield to be recycled and was bound into large bale-like bundles.

An Oregon State Police trooper investigating the incident conducted a truck inspection that revealed no violations and the driver was not cited.