Greenfields School and Sports College in Goldings, Northampton has been evacuated following a suspected chemical leak.
Police are still at the scene to deal with traffic management and support the Fire and Ambulance services. No children have been hurt as a result of the incident.
Residents in the immediate area have been asked to keep windows and doors closed whilst the incident is dealt with.
Two adults are being treated at Northampton General Hospital with mild breathing difficulties.