HARPER (AP) — The drivers of two commercial vehicles were killed in a head-on collision on U.S. 20 near Harper, Oregon, just west of the Idaho border.

Oregon State Police say a commercial truck and trailer was driving east at about 9 a.m. Saturday when it drifted into the westbound lane and into the path of a commercial truck.

The two vehicles collided and burst into flames, killing both drivers. Brian Brunscher, 37, of Springfield, was driving the white 2016 Kenworth commercial truck that entered the oncoming lane, and James Shorten, 55, of Portland, was driving the orange 2015 Freightliner.

A Jeep Wrangler behind the truck collided with its trailer, and a Kia Spectra hit the back of the Jeep. No one was injured in those vehicles, which were operated by Idaho drivers.

About 400 gallons of diesel spilled into the road, closing US 20 for more than 12 hours.

The investigation is ongoing, but speed and weather are believed to be contributing factors in the crash.

OSP were assisted by the Malheur County Sheriff’s Office, Oregon Department of Transportation, Ontario Fire and Rescue, Ontario Haz-Mat, Vale Fire and Rescue, Steve Rich Environmental Services and Haren-Wood Funeral Chapel.