Ameren cautions Mylar balloon use The Telegraph FacebookTwitterEmail Mylar balloons are metallic and conduct electricity, resulting in surges and shorts that have the ability to knock out power, start fires and cause significant damage to the electric grid. COLLINSVILLE — Ameren Illinois asking customers to properly dispose of Mylar balloons in an effort to reduce the potential for power outages. On April 9, more than 1,200 customers in Champaign/Urbana lost post for about three hours when Mylar birthday balloons became entangled in power lines. The balloons were safely removed and power was restored around 10:30 p.m. Mylar balloons are metallic and conduct electricity, resulting in surges and shorts that have the ability to knock out power, start fires and cause significant damage to the electric grid.