A feared chemical gas leak at Fonterra's factory at Hautapu in the Waikato has turned out to be a blown high-pressure air hose.
There was a "reasonably significant" response to reports of a possible gas leak at the factory at around 3:30am on Friday, says Fire Service norther communications shift manager Jarron Phillips.
Seven fire appliances, including a hazardous materials unit from Hamilton, were called to the factory, on the outskirts of Cambridge.
Firefighters in chemical suits and wearing breathing gear entered a service tunnel where they found the blown hose, Mr Phillips said.
Factory maintenance staff were accompanying firefighters into the tunnel to fix the problem.
About 300 people work at the Fonterra factory, which produces milk powder, casein, cheese and other specialist products.
It was not clear if production was affected.