The roof of the Frito Lay plant in Beloit caught on fire.
Beloit firefighters say the fire started near a smokestack on the roof just before midnight. Employees were evacuated and followed emergency procedures including turning off power. Once the power was shut off the fire died out.
Firefighters stayed on the scene to put out hot spots for almost an hour. The cause of the fire is still under investigation.
Firefighters say the damage is limited.