Firefighters responded to reports of a strong odor Thursday morning at Bunnell High School in Stratford.
Hannah Cologgi was in class when she noticed a scent that she says smelled a lot like gas.
"It was very strong," she says. "It gave some kids headaches."
Responders evacuated about 20 students to the school's library. They later determined that the scent was the result of repairs being done on the roof.
Firefighters stayed at the scene for hours, saying they wanted to make sure nothing else could be smelled or detected. Only one wing of the school was affected.
No students had to seek medical attention.
Firefighters tell News 12 that work on the roof has been stopped for now. They say the town's public works director would have to weigh in to determine when work can resume.