MADISON, Wis. — A fire involving decorative cotton balls at a downtown fraternity house early Friday damaged a smoke detector, according to the Madison Fire Department. Firefighters were sent to the 200 block of West Lakelawn Place shortly after 3 a.m. following a fire-alarm call. Evacuation was underway when crews arrived, but the alarm was no longer sounding. Fire officials determined that a lighter had been used to ignite cotton balls attached along the ceiling as decorations. The flames had been extinguished before firefighters reached the building. The closest smoke detector was damaged in the incident. Fire officials advised occupants to remove any remaining cotton-ball decorations, contact the alarm company to replace the detector and avoid silencing future alarms. The fire department did not report any injuries or provide an estimate of property damage.