Crews from the Milwaukee Fire Department were called early this  morning to Wisconsin Paperboard Corporation.  About 20 people were working inside the building at 4:15 A-M when the fire started.  Employees say the fire, which started in a dryer at paper mill number-two, got out of control in just a few seconds.  The official cause of the fire hasn’t been determined.  Witnesses described seeing smoke coming from the roof of the building.  All workers were evacuated, and no injuries were reported.  There have reportedly been at least five fire calls from that location over the last 25 years.