Traffic was snarled Thursday on the northbound San Gabriel River (605) Freeway in the Whittier area after a dump truck overturned, spilling debris and gravel onto the roadway.
The crash occurred about 6 a.m. near Washington Boulevard, according to the California Highway Patrol.
Some northbound lanes were blocked in the area while crews worked to clear the debris, which included pieces of concrete, according to reports from the scene.
Caltrans reported all northbound lanes were closed on the 605 Freeway in the area of the spill. The southbound HOV lane of the 605 Freeway was also blocked. Northbound traffic was reduced to one lane until 7 a.m.