About eight people were taken to hospital in Timaru after a gas leak at a factory in Washdyke.
Fire and Emergency were called to the ammonia leak after 9:30pm on Thursday on Meadows Road.
Eight crews and a specialist hazard command unit worked with engineers to lower pressure in the system and decontaminate the area.
Before ambulance crews arrived, fire crews gave oxygen to people from the factory.
Crews left the scene at 2.15am yesterday after sealing the leak.
