The multi-vehicle collision occurred shortly after 3 a.m. on the southbound side of the freeway at Indiana Street, near Boyle Heights, according to the California Highway Patrol. Firefighters responded to the scene and doused dramatic flames that engulfed the big rig.
An ambulance was requested at the scene, but whether anyone was seriously injured in the collision was unclear.
The CHP issued a SigAlert that impacted traffic for hours.
Traffic was backed up on the southbound side of the freeway as crews worked to clear the scene.
The freeway was fully reopened shortly after 1:30 p.m.