A big rig and a truck collided in Banning Thursday morning, causing at least one injury and snarling eastbound traffic.
The crash, reported at 7:14 a.m., blocked all four eastbound lanes west of Eighth Street, according to the California Highway Patrol.
The CHP said the big rig had jackknifed and spilled between 100 and 150 gallons of diesel onto the roadway, spurring a hazardous materials cleanup crew to be dispatched to the crash site.
Injuries were reported, although specifics were not provided.
Banning police officers temporarily closed the eastbound on-ramp at Eighth Street.
Three lanes were reopened by 9:30 a.m., but the slow lane remained shuttered while crews worked the scene.