Police and fire services have confirmed the chemical leak at Lynn’s College of West Anglia on Friday was a deliberate act.
Police are working with staff at the college to identify the cuplrits, who are believed to have introduced a substance to the third floor area.
Emergency services suggest it is likely to have been a CS type substance, mace or pepper spray but this has not been confirmed.
Principal David Pomfret said: “I would once again like to thank the emergency services for the efficiency and professionalism of their operations on Friday. I would like to reassure students and staff that we have already started an internal investigation to support the police and will be leaving no stone unturned to ensure this matter is brought to a speedy conclusion.”
One adult student was taken to hospital as a precautionary measure and was released on Friday afternoon after treatment.
The building is fully open today and teaching is taking place as normal.