Portland high and middle schools were evacuated on Wednesday morning because some students fainted in class.
The superintendent's office confirmed the evacuation of both schools, which share a campus on High Street.
Officials said the students became extremely dizzy in the middle of a chorus class and had to be taken to the hospital.
They did not specify how many students were affected.
They suspected that it happened because they were overheated from so many of them being in the same room at the same time.
Still, both school buildings were evacuated due to concerns that it could have been something in the air.
"It was scary," said Shelby Benoit, a student and eyewitness. "My mom and dad are EMTs so I know what to do, but just sitting there watching my friend pass out three or four times was really, really scary."
Students have since returned to class. The buildings were deemed safe by fire officials.
Some parents, however, decided to take their children home for the day.
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