SCHOFIELD, Wis. (WSAW) -- Fire crews responded to a fire at Northland Cold Storage on Grossman Drive on Monday.
Employees inside the building at the time reported smoke at around 3:15 Monday afternoon.
Firefighters from Riverside Fire District went inside and found heavy smoke coming from a large stack of cardboard inside a maintenance area.
"Initial investigation appears that a wall heater system malfunctioned and started that stack of cardboard on fire," said Riverside Fire District Chief Rob Bowen.
A hazmat team employed by the corporation came in to make sure the ammonia system was working properly, which was housed inside the area where the fire started.
No one was hurt.
At this time, the owners are working to clear the area.
A portion of Grossman Drive was closed off for a couple hours while fire crews were on scene. The road has since been reopened.