Staff and students at Pettit Private School in Decatur evacuated the building around 1:45 p.m. Thursday after light smoke was seen in the building located in the 700 block of Deer Park Road. The Decatur Fire Department responded and discovered a light haze in the building, according to Fire Chief Mike Richardson. He said the cause of the smoke was an overheated exhaust fan. Kids and staff were allowed back in the building after about 30 minutes. Wise County Medics also responded and passed out water for students and staff.