The crash between a big rig and at least one other vehicle was reported shortly after 4 a.m. near the 57 Freeway.
Officials said one person was transported to a local hospital in unknown condition.
Traffic was backed up to Glassell Street and Kraemer Boulevard as crews worked to clear the scene.
All lanes were reopened at about 6:30 a.m., according to officials from the California Highway Patrol.