Eastbound Interstate 70 was closed for about three hours Wednesday at Georgetown due to a semi-truck fire and a subsequent crash, authorities said.

The Colorado State Patrol said the semi-truck fire happened just after 12:30 p.m. Wednesday when the big rig’s brakes caught fire, forcing emergency crews to shut down the state’s primary eastbound artery.

During the closure, a second crash involving six vehicles happened in the backed-up traffic, troopers said.

“Another semi-truck approaching the back of the stopped traffic on the down grade was unable to stop before colliding with the vehicles stopped in traffic,” the state patrol said in a news release.

Troopers said three people had to be taken to the hospital by ambulance and a fourth person sought medical attention on their own. The extent of the injuries was not immediately known.

Crews were able to clean up the roadway and re-open the interstate by 3:20 p.m., troopers said.