The Whittier Daily News reports Jose Melena was found shortly before 7 a.m. Thursday at the plant in Santa Fe Springs.
Erika Monterroza is a spokeswoman for the California Division of Occupational Safety and Health. She says it's unclear how the man ended up inside a cooking device called a "steamer machine."
The state agency has launched an investigation.
Bumble Bee Foods spokesman Pat Menke expressed condolences to Melena's family in a written statement. Menke says operations at the canning facility will be suspended until Monday.