The body was discovered by a member of staff at Bell Waste Control on Wednesday.
Humberside Police said a post-mortem examination confirmed the infant was a newborn boy.
The cause of his death is yet to be established and further tests will be carried out, police said.
The teenage mother of the baby contacted police in a distressed state on Wednesday and is receiving medical care at Scunthorpe General Hospital.
Police are continuing their inquiries into the circumstances of the baby’s death.
The body was found by a traumatised member of staff as he worked on a section picking off cardboard, wood, paper, metal and other objects for recycling.
He originally mistook it for a doll or cuddly toy, but on realising it was a child dropped it instantly.
A statement from Humberside Police said: “A post-mortem examination of the baby found at Bell Waste Control in Scunthorpe on Wednesday May 2 has confirmed that it was a newborn baby boy.
“However the cause of death is yet to be established as the results came back inconclusive and further tests will now be carried out.
“The teenage mother remains in hospital receiving medical care and police inquiries into the circumstances of what happened are continuing.”