Dairy product leaking from a tanker that crashed in the Awakino Gorge on State Highway 3 yesterday morning could wreak havoc with fish and aquatic life in the river.
Emergency services were alerted to the crash about 5.30am and the driver had been trapped but was freed by 6.20am.
The Taranaki Rescue Helicopter transported him to Taranaki Base Hospital with minor injuries.
Waikato Regional Council emergency response manager Rob Dragten said the tanker was taking evaporated whey protein, a product of cheese making, from Lichfield to Kapuni for further processing or disposal when it crashed.
He said the sticky, sweet protein had been leaking into the Awakino River.
"Because this material is high in sugar it breaks down in water quickly and reduces the amount of oxygen in the river."
A lack of oxygen could harm fish and other aquatic life.
The tanker is said to have been carrying about 25,000 litres of the dairy product, but it was unclear how much had made its way into the river.
Mr Dragten said he did not expect major water quality issues as a result of the crash.
"The Awakino's a big river and it's close to the sea. Biochemical oxygen demand takes a while to take effect, a few days, and with the small amount of product leaking out we would expect it to have moved through the river system before it takes hold."
He said council staff will be making an environmental risk assessment at the scene and looking at how the environmental threat should be managed. "We'll be keeping a close eye on oxygen levels over the next few days."
"We will work closely with emergency services to look at what we can do to prevent environmental damage in the wake of this accident," said Mr Dragten.
The 40-tonne tanker lost control on a corner with a 45km speed limit 5km north of Mokau.
Fire trucks from Mokau and Urenui attended and central fire services shift manager Mike Wanoa said the tanker careered off the road and into the river.
The road was closed at intervals so the tanker's load could be pumped out and two cranes could remove the vehicle.
- Taranaki Daily News
Is this the best summer ever?Related story: Wellington sizzles in January heat