Officials in western New York state are trying to figure out how a bare human foot got mixed in with recyclable trash on a conveyor belt at a landfill.

Sheriff Phil Povero says a worker at the Ontario County landfill's recycling plant spotted the severed right foot Monday night, the Daily Messenger reported.

Povero says authorities believe the foot is an adult's, but aren't sure whether it belonged to a man or woman.

The Monroe County Medical Examiner's office will perform forensic tests on it.

The recycling plant remained closed Tuesday while investigators searched for clues. Povero said the trash in the area where the foot was found came from 15 New York counties as well as parts of Canada.