A truck carrying radioactive material hit a power pole and jackknifed, closing State Highway One in Tirau late last night and blocking the road until early today.
An Auckland-based adviser monitored the clean-up with a Geiger counter as firefighters worked wearing nuclear, biological and chemical protective suits.
Hamilton's hazardous materialsunit was called to the crash and chief fire officer Roy Breeze said isolating the 30kg container of radioactive material was a time-consuming task.
The crew was well aware of the dangers faced, he said.
An Environment Waikato spokeswoman said the crash could have been a catastrophe, but there had been no leaks.
"We're keeping a watching brief, but everything seems fine," the spokeswoman said.
