Residents of the north Waikato town of Tuakau were evacuated on Tuesday afternoon after a large amount of an unknown chemical entered the drains near the town’s water treatment plant, and others were told to shut themselves indoors while emergency crews tried to work out what the substance was.
Fire and Emergency New Zealand said firefighters were called to a hazardous substances incident reported at 4pm. In a statement, the agency said residents had been evacuated from houses in Kowhai Street, Cottle Lane and George Street, and that another two households had chosen to leave on their own. Waikato District Council said 15 homes were evacuated in total, after reports of a smell of fuel in a Tuakau street.
“Other residents remaining in the area are advised to stay inside with their doors and windows closed to avoid the risk of being exposed to fumes,” Fire and Emergency said.
Hours after the first call, the basic question had still not been answered. “The nature and origin of the substance is not yet known,” the agency said. Crews set up a control centre in the area, police helped with the evacuations, and specialist advice was sought from the Queensland Fire Department to help identify what had gone into the drains. Fire and Emergency said it was working with Waikato District Council and Watercare on a plan to flush the drains safely.
Waikato mayor Aksel Bech said a strong fuel or LPG smell was detected near the water treatment plant, and that the substance was suspected to have come from an underground petrol or LPG storage tank.
“[That] led us to believe that perhaps there might have been an issue from inside of one of the petrol stations in Tuakau, it would have to be somewhere with a bit of volume in order to actually be able to produce a smell,” Bech told RNZ. “Very quickly when that smell was detected the water that goes into the watercare facility was diverted off into a pump so as not to contaminate anything within the plant. That is under control.”
Bech said Watercare staff had been working from manhole to manhole trying to find where the spill had entered the network. That is slow work. A drainage system does not tell you where something was tipped in, only where it has ended up, and a volatile fuel or gas moving through a confined pipe carries an obvious risk to anyone lifting a cover to look.
The council was clear on the point most people in the district would have been worried about. There was no impact on drinking water or stormwater networks, it said, and no issues with drinking water quality. The pipes involved were wastewater pipes, and the flow heading for the treatment plant was diverted before it reached it.
That distinction matters more in Tuakau than it would in most small towns. The water treatment plant on the edge of the town draws from the Waikato River and is one of the more significant pieces of drinking water infrastructure in the upper North Island. Watercare treats water there and pipes a large share of it north to Auckland, and the site was expanded quickly during the 2020 drought when Auckland’s storage lakes ran low. A chemical release that reached the wrong part of that site would be a far bigger story than an evacuation of three streets.
It did not. On the information released on Tuesday evening, the diversion worked as intended and the problem stayed inside the wastewater network, where it is a serious nuisance and a hazard to the people working on it rather than a threat to the town’s taps.
For the households moved out, the practical situation was less tidy. Evacuations of this kind are usually short, but they are open ended by nature, because the decision to let people home depends on the fumes clearing and on somebody being able to say with confidence what the substance is. Until the source is found, there is also no guarantee that more of it is not still leaking into the same drain.
Tuakau sits just south of the Auckland boundary and has grown quickly over the past decade as buyers priced out of south Auckland have moved down State Highway 1 and the Waikato Expressway. It is now a town of several thousand people with a main street, service stations and light industry sitting close to housing, which is a common enough arrangement in provincial New Zealand and one of the reasons a single underground tank problem can put a residential street out of its homes.
Incidents involving fuel entering drains are not rare in New Zealand, but the scale here was unusual enough to bring in overseas expertise. Fire and Emergency’s hazardous substances teams routinely deal with spills from vehicles, farms and workshops. Calling on the Queensland Fire Department for identification advice suggests crews on the ground were not able to match what they were smelling and measuring to anything straightforward.
Fire and Emergency asked the public to stay away from the area until further notice. Anyone in the surrounding streets who had not been evacuated was told to keep doors and windows shut, which is the standard advice for airborne fumes and the reason the cordon was drawn wider than the houses that were actually emptied.
The next steps are identifying the substance, finding and stopping the source, and flushing the pipes without pushing a fuel and air mixture somewhere it can ignite. None of those had been completed when the agencies last spoke publicly on Tuesday evening, and the council and Fire and Emergency both said further information would follow.
Do you live in Tuakau or know the streets involved? Tell us what you saw and heard in the comments below.
This article was written by AI, briefed to report the facts, hopefully without some of the bias people bring to the job 🙂
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