Some westbound traffic on Interstate 70 is still being routed over Loveland Pass after a Federal Express truck caught fire before 7 a.m. closing the highway near the Eisenhower Tunnel.

The interstate is now open to passenger cars but remains closed to commercial vehicles while clean-up crews from Denver mitigate a hazardous-materials situation.

Authorities don’t know what ignited the fire, but the truck did not crash and no one, including the driver, was injured, according to Colorado State Patrol.

However the flames ruptured the truck’s saddle tanks, spilling diesel onto the highway. The fuel must be completely cleaned up and any contaminated soil near the road removed before traffic can be allowed back on the highway.

“The EPA has strict rules that if something like this happens it has to be cleaned up in a certain amount of time,” Colorado State Patrol spokesman Tpr. Nate Reid said.

Colorado State Patrol received the call at 6:50 a.m. the highway has been closed to traffic for several hours this morning, causing back ups on the westbound lanes.

The truck caught fire just west of the tunnel at mile marker 210.