Shortly after 11 a.m., firefighters responded to the school at 385 Mill Street for a fire on the second floor.
The school was being evacuated when first responders arrived and an extinguished fire was found in a bathroom.
Officials said the fire was put out by the school’s automatic sprinkler system and was contained to the one room.
One school staff member was evaluated for smoke inhalation but did not need to be hospitalized.
Officials said the fire was intentionally set, a suspect has been identified, and charges are pending.
School dismissed early for the day after the incident.