Police are investigating a fire at a North Canterbury plastics recycling factory after it was found to be deliberately lit.
Fire safety officer Sue Trafford told NZPA the fire was lit outside the Kaiapoi building, but she could not comment on the cause.
The blaze, which started about
3.30am yesterday, was attended by 17 fire appliances.
Toxic fumes forced the evacuation of local residents who were not allowed to return to their homes until yesterday afternoon.
Smoke and dust from the fire forced emergency services to evacuate Stone St, where the two-storey building was located.
There had been a large amount of smoke over and throughout Kaiapoi which was of a toxic nature, a fire service spokeswoman said.
Environment Canterbury's Pollution Hotline was inundated with calls yesterday morning, from people concerned about the strong smell of burning plastic from the fire.
Fortunately a stiff northeast breeze blew the toxic smoke away from nearby houses, ECan's enforcement team leader Tony Smith said.
"Our main concern was to contain the run-off from the large volume of water, used to put out the fire, from entering the Kaikaanui Stream," he said.
Diverting the water via the stormwater system into a retention pond over the road met with limited success due to the large quantity.
The water contains tiny plastic beads, a by-product of the recycling process.
"Samples from the stream have been taken and we expect results early in the New Year," Mr Smith said.
- NZPA
