SUMMIT COUNTY, Colo. (CBS4) – Highway 6 over Loveland Pass is closed after a driver was killed in a crash Thursday morning. The collision happened at 8:26 a.m. in Summit County between a commercial truck and a pickup truck and the cleanup has been complicated by the fact that hazardous materials were onboard the commercial truck.

A commercial truck crashed in Summit County on Loveland Pass on Highway 6 in Colorado’s mountains on Thursday morning. (credit: TJ Sanders Krystal 93 radio)

So far it’s not clear what caused the accident, but black ice was being reported by emergency crews while they were responding to the crash.

READ MORE: Flags To Be Lowered To Honor Colorado Springs Shooting Victims

READ MORE: Four Congressmen Join Colorado Teacher & Students To Make a Japanese Internment Camp A National Historic Site

“Our crews reported very slick conditions out there this morning, but the cause of the accident and further investigation will be handled by the Colorado State Patrol,” said Summit Fire & EMS spokesman Steve Lipsher.

A photo from the scene taken by a passerby showed a double trailer truck off the side of the highway in a ditch in snowy conditions.

The driver of the pickup truck was killed and the commercial truck driver wasn’t hurt.

MORE NEWS: Victims Identified In Colorado Springs Mass Shooting At Birthday Party

Authorities said they weren’t sure what hazardous substances might be onboard the commercial truck beyond some gas that leaked from it.