Christchurch residents are being reassured they can flush their toilets after the city's wastewater treatment plant went up in flames on Monday afternoon.
At the fire's peak, 50 firefighters fought the burning treatment plant after a fire broke out on the roof of a building used for filtrating the city's sewage.
Thick black smoke blew across the garden city, the smell reported as far away as Rolleston, concerning some residents Newshub spoke to.
"Dunno if there's chemicals in there or anything like that, pretty scary," one said.
Christchurch residents were warned by health officials on Monday to stay inside and close all windows, but some made the most of a good photo.
Residents who spoke to Newshub didn't realise how large the fire was until they stepped outside.
"We just saw it as we were finished having lunch," one said.
"She told me there was a chimney with funny-looking smoke and then we walked out to see this."
The Christchurch City Council is reassuring its residents that they can still use the toilet as normal.
"We're working through a number of options for treating the wastewater and no doubt we'll be trialling those over the next few weeks."
Christchurch fire crews spent Tuesday morning dampening down hotspots. FENZ Canterbury Area Commander Dave Berry told Newshub the flames had jumped to a second building causing both fibreglass roofs to collapse.
"The tanks themselves are roughly about 50 meters in diameter and eight metres deep and six metres of that is compressed."
An independent investigator will work with Fire and Emergency to determine the cause of the fire.
