IAWAI chief executive Peter Winder said investigators were looking at a potential source near to the wastewater pump station in Tuakau, which channeled from a number of properties. Early investigations indicated a potential source could be an industrial property in the town.
“It is extremely frustrating that this entire event was needless and appears to have been completely avoidable.
“We appreciate the efforts of [Fire and Emergency NZ], police and other emergency services who responded, as well as our IAWAI staff and Watercare and thank the residents for their understanding.”
Winder said the incident was a stark reminder that rules around wastewater networks were there for a reason.
People or businesses found responsible for allowing non-compliant substances into waterway systems could be fined up to $200,000 under the Local Government Act.
Fifteen homes were evacuated yesterday, while Fire and Emergency northern shift manager Josh Pennefather said three firefighters had been checked out by ambulance staff after being exposed to the chemical.
A St John spokesperson said two ambulances and a rapid response vehicle were sent and two people, in a moderate condition, were checked by ambulance staff. They did not need to be taken to hospital.
Specialist advice was being sought yesterday from the Queensland Fire Department, which provides expertise in dealing with hazardous chemicals.
As soon as the smell was detected, the water was diverted to avoid it contaminating the water treatment plant, while workers had been going from manhole to manhole to find the source of the spill, Bech said.
Around 10.30pm, residents were returning home and four fire appliances were preparing to leave, Fire and Emergency Assistant District Commander Brad Harvey said.
Firefighters had been flushing the drains and air-quality readings had returned to safe levels.
Residents evacuated earlier in the evening were able to return home. The advice to other residents to stay inside with doors and windows shut was lifted.
“The scene will be left in the hands of local water management staff. The nature and source of the substance which prompted the emergency response has not yet been established,” Harvey said last night.
Waikato District Council said IAWAI was working with Fire and Emergency to flush the pipes, with 15 homes evacuated for safety reasons.
WorkSafe said it was notified of the incident by Fire and Emergency but “has not opened an investigation at this stage”.
Drinking water and stormwater networks were not affected.