Workers at the trash facility discovered the body among recyclable items shortly after 6 p.m. on Friday.
The body was described as a black woman in her 20s.
Investigators believed the body was probably delivered to the facility sometime Friday among the numerous truckloads of materials that had been dropped off for processing.
The facility collects trash and recyclable material from across Southern California.
The coroner's office was investigating the cause of death.
