Three students are in stable condition after suffering respiratory injuries in a chlorine leak at the Lasnamäe Gümnaasium's swimming pool on Tuesday afternoon.
The leak triggered an alarm at 14:42, when 300 people were evacuated from the school and rescuers were called to the scene, an administrator told uudised.err.ee. An ambulance was dispatched to take the first patient to the hospital at 15:24, according to Delfi.
The leak had reportedly occurred in a ancillary room at the school's swimming pool, which students from another school were using at the time.
In summer 2008, 33 people were exposed to chlorine fumes in Kalev Spa in downtown Tallinn after pool chemicals came into contact with an acidic cleaning compound.