A small exterior fire melted some of the Boone Hospital Center sign Tuesday around 11:30 p.m.
What began as an investigation was upgraded to a commercial structure fire as crews arrived on the scene and witnessed portions of the Boone Hospital Center sign on fire and dripping onto the roof.
Crews found there had been a fire in the sign and the melting plastic had dripped onto the roof, melting through the roof membrane, and into the foam roof insulation.
The cause of the fire was determined to be electrical, but the assistant fire marshal could not rule out a lightning strike; due to the thunder storms in the area at the time of the fire.
Damage to the sign and the roof are estimated at 5,000 dollars.
There were no injuries reported.