Overturned big rig causes SigAlert on 91/110 Freeway connector in Gardena

An overturned big rig caused a lengthy SigAlert on the 91 Freeway in Gardena on Monday evening.

The crash was reported just after 4 p.m. on the 110 Freeway and 91 Freeway connector road, according to the California Highway Patrol. 

By the time that officers arrived, the driver had self-extricated from the truck, CHP said. 

One person was hospitalized following 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 place as Caltrans crews worked to clear the scene. They had opened just one lane to traffic, creating a considerable backup in the area. 

CHP officers said that there was no estimated time for all lanes to reopen. 

Cleanup crews used two massive cranes attached to trucks to try and upright the truck. However, it appeared that the truck's walls began to break while it was being lifted, which was apparent by a large hole that had started to form. 

It's unclear what the truck was hauling.