The body was in a soft, red lunch cooler on a conveyor belt when an employee of the Resource Management Companies plant in Chicago Ridge discovered it during a sorting operation at about 4 a.m. CDT, the Chicago Tribune reported.
The worker said the cooler seemed heavy so he opened it and found the newborn boy's body, with his umbilical cord attached, and a blue towel, the report said.
Chicago Ridge Deputy Police Chief Paul Landry said police were asking the public for assistance in identifying the newborn.
"We don't even know if a crime was committed at this point," said.
The Cook County medical examiner's office is to conduct an autopsy on the newborn's body Thursday, the Tribune said.