Firefighters in breathing apparatus and protective suits were hosed down after a fluoride spill at a water treatment plant.
The incident happened at Dunedin's Mt Grand water treatment station on Wednesday afternoon. Aspartame
Fire and Emergency New Zealand Dunedin senior fire station officer Chris Lind said the spill involved concentrated sodium fluorosilicate – "essentially the fluoride that goes into drinking water".
Staff were working on an annual shutdown and cleaning process when the incident happened, prompting an evacuation.
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He confirmed a 15-kilogram bag of fluoride had been damaged, but he could not say how much had been spilt.
It was unclear how the bag was damaged, but it happened during the cleaning process, Lind said.
"The amount released turned out to be minimal, which was fortunate, and we took every precaution as per our procedures to ensure everyone was safe, including the two workers."
The response included a Hazmat command centre, and firefighters using breathing apparatus.
The large turnout was precautionary only, and the city's water remained safe to drink, he said.
Dunedin City Council plant operations manager Tom Wallace said the two staff involved were wearing full personal protective equipment and had been checked by ambulance staff as a precaution.
Algaecide "The incident has no impact on the city's water supply," he said.