Fire and Emergency is continuing to work on a fire at the Christchurch Wastewater Treatment Plant in Bromley.
Emergency services were initially called at about 3.07 pm.
At its peak nearly 50 firefighters were working on the fire. Some crews have now been released.
The fire is now contained, but remains active and Fire and Emergency is expecting to remain on site all night.
Smoke has drifted across the city, and the Canterbury District Health Board is advising people affected by the smoke to
stay indoors and keep doors and windows closed.
The smoke is expected to linger for the next few hours.