Officials now know what caused this week’s costly fire at a private country club in Waterloo. Investigators have determined that Monday’s early morning fire at Sunnyside Country Club was sparked by spontaneous combustion. They say heat from a dryer ignited oily rags in a lower level laundry and storage room. Those rags — used to remove oil from cooking equipment — were folded and stacked in the room after being cleaned and dried.

Investigators say flames from the rags then spread to linens and uniforms that were also in the room. The fire created a cloud of heavy smoke that filtered throughout the building. The smoke set off an upstairs sprinkler, which kept the flames from spreading. While the fire was contained to the basement area, officials say much of the clubhouse sustained heavy smoke and water damage.

Estimates on the damage range between 100-thousand and one-million dollars. Officials haven’t yet determined whether the building can just be cleaned or if the clubhouse will have to be remodeled.

Audio: Elwin Huffman report. :47 MP3