Nine people have been taken to hospitals around the Hunter following a chemical leak at a Beresfield factory.
Emergency services were called to the processing factory just before 7:30pm Friday following reports of an ammonia leak.
Nearly 350 employees were evacuated, while 11 were treated on scene after being exposed to the toxic chemical.
Nine were then taken to the John Hunter, Maitland and the Calvary Mater hospitals for observation.
Police and SafeWork NSW are investigating.