(Waupun) The Waupun Fire Department responded to a building that was filling with smoke Saturday morning. Crews were dispatched to W7185 Highway 49 shortly before 9am and upon arrival, discovered a smoldering fire on a workbench in one of the businesses. Firefighters used a fire extinguisher to put out the blaze and then set up ventilation fans to disperse the smoke that was in the building. Fire Chief BJ DeMaa says the structure is a multi-tenant commercial building owned by Samsyl Properties. The area of the building where the fire occurred was in a space leased by Home Contractors. DeMaa says damage was limited to a workbench in the shop area. He adds that no firefighters were hurt during operations. The cause of the fire is believed to be spontaneous combustion of a stain rag left on the workbench. The Waupun Fire Department is reminding the community, when they dispose of stain-soaked rags to put them in a non-combustible metal container with a metal lid. Assisting at the scene were fire departments from Alto, Brandon/Fairwater, Beaver Dam and Fond du Lac Count RIT Team 4, the Waupun Police Department, Dodge County Sheriff’s Department and Lifestar Ambulance.