WAUKESHA, Wis. (CBS 58) -- The Waukesha Fire Department was called out for a report of a fire at the Arby's on Silvernail Road.

It happened around 9:17 a.m. on Friday.

The flames were seen shooting from the roof of the restaurant.

Fire crews entered the building and went to the roof, extinguishing a fire in the deep fryer ventilation system.

The fire was contained to the ventilation system.

The fire was investigated jointly by the Waukesha Fire and Police departments and determined to be caused by a cardboard oil container inadvertently left on top of the fryers.

One employee was assessed by fire personnel and released on scene. 

Damage estimate is not available at this time. Arby’s restaurant will remain closed until it passes inspection by the Waukesha County Health Department.