An overturned big rig triggered a lengthy SigAlert on Highway 91 in Gardena Monday evening.
According to the California Highway Patrol, the crash was reported at the 110 Freeway and 91 Freeway junction just after 4 p.m.
By the time officers arrived, the driver had freed himself from the truck, CHP said.
One person was taken to the hospital after the incident, but it was unclear if it was the driver of a possible passenger in the tractor-trailer.
As of 9 p.m., the closure remained in effect as Caltrans crews worked to clear the scene. They had only opened one lane to traffic, causing a significant backup in the area.
CHP officers said there was no estimated time when all lanes would reopen.
Cleanup crews used two huge cranes attached to trucks to try to right the truck. However, it appeared that the walls of the truck began to break as it was lifted, evidenced by the formation of a large hole.
It is unclear what the truck was carrying.
