Glastonbury police responded to Glastonbury High School after a chemical issue was reported inside school Friday morning.
The emergency call came in at 10:09 a.m.
A science class using chemicals had a reaction, according to Superintendent Dr. Alan Bookman. He says chemicals cleaned up with paper towels began to smolder and the school was evacuated as a precaution.
Police and DEEP were called to the scene to investigate. No one was injured.
Students have been allowed back to class.