State Fire Marshall investigators believe an electrical short caused the fire about 6:00 Thursday morning in the school's marketing department.
Crews used a fire extinguisher and some water to stop the blaze, but Washington County fire officials called a HAZMAT team from Panama City to investigate a strange odor detected after the fire.
They discovered the water caused some kind of chemical reaction that produced an ammonia smell.
"By that time, the State Fire Marshall was here. He made the decision to bring in others to help him determine exactly what caused it, exactly what was causing that chemical presence that was in there," says Jerry Tyre, Washington County School Superintendent.
Authorities say they still don't know where the ammonia came from, but it was not enough to pose any threat.