Personnel are working to clear a rural road outside of Feilding after a truck crashed, spilling bitumen on the road.
The surrounding area had to be evacuated while workers cooled the heated tanks to avoid the risk of an explosion while moving the overturned truck.
Emergency services were called to the scene on Halcombe Road at approximately 8.40am this morning.
Fire Service area commander Manawatu Rodger Calder said it was the third crash in three days on the "notorious" stretch of road.
"The truck has been coming down the hill towards Halcombe but it appears his back end has slightly run off the road. He has hit a culvert and then been flipped over."
He said the male driver of the truck, owned by Rex Bisman Ltd, sustained minor injuries, including a black eye and bump to the forehead. He was treated at the scene by ambulance staff.
Mr Calder said the truck was carrying approximately 8500 litres of bitumen and was travelling to Taihape.
During the accident, the tanks carrying the bitumen have split open allowing it to flow onto the road.
Mr Calder said some had gone into a culvert which had now been blocked, but some had also gone into a drain.
"We are working to see how far it's gone but, at this stage, we don't think it's gone too far. We're now spreading sand on the road to absorb any extra carbons let off from the bitumen."
At 11.30am, a 200m exclusion zone was implemented so a crane could pull the truck back onto its wheels. Mr Calder said they had to wait until the temperature of the tanks had decreased by more than 20 degrees.
"We are removing anyone other than emergency service personnel while we do this due to safety; this thing could go up," Mr Calder said.
Once the truck was removed, the fire service ceased operations and left roading contractors to continue the cleanup.
"The road will be closed for some time so, for today, we are encouraging people to take alternative routes," Mr Calder said. "The bitumen has solidified so it will have to be scraped up and reinstated."
He said police would take over once the cleanup was done to investigate the crash. They also had representatives from the Manawatu District Council and Horizons Regional Council onsite, advising them on the environmental impacts of the spill.
Mr Calder said the first crews on the scene tried to contain the bitumen from spreading further until contractors could arrive with sand to assist.