A fire displaced four residents Saturday evening and caused about $200,000 in damage to a two-story house at 416 E. Wisconsin St. Fire Chief Tom Cullen said two residents escaped from the burning home and notified a neighbor to call 911. No one was injured. Witnesses reported that the fire might have been caused by an explosion of a propane grill. The fire started on the front porch that contained the propane grill, Cullen said. The cause of the fire remains under investigation. Firefighters arrived shortly after 6:15 p.m. to find the house engulfed in flames on one side. The fire had spread to two downstairs rooms and to the attic.