VIDEO: Emergency crews responded to a paper mill fire on Milwaukee's east side early Thursday morning. Firefighters were called to Wisconsin Paperboard Corporation around 4:15 a.m. The business is located near Thomas Avenue and Newhall Street. At least 20 workers evacuated the building. Employees told WISN 12 News they tried using a fire extinguisher to put out the fire on a piece of equipment, but the flames spread too quickly.