Oil-soaked rags sparked a fire that evacuated Fort Collins High School today.
No one was hurt but it took about 90 minutes for firefighters to clear smoke from the school with fans.
The rags, which had been used to apply linseed oil to instruments in the orchestra room, spontaneously combusted, according to Poudre Fire Authority spokesperson Carie Dann.
They had been left outside to dry before being stored in a cabinet under a sink, but enough residue remained on the rags to start the reaction, Dann said in a statement.
Fire damage was limited to the cabinet.
Today was the last half-day of classes, and only sophomores and juniors were at school.
Fire officials say linseed oil and other natural oils such as mineral, fish, cottonseed and cod liver oil, can spontaneously combust as they evaporate, combining with oxygen and generating heat.
That heat needs to dissipate as quickly as it is produced or a fire can start.
Assistant Fire Marshal Holger Durre recommended that oil-soaked rags should be hung outside or in an area with ample circulation around the rags. When dry they should be placed in a metal container with a tight lid.
