A b-double truck carrying building waste rolled over at the South Kempsey roundabout on Macleay Valley Way at around 10.30 this morning.
Emergency services are on scene and traffic is being controlled.
The male driver of the truck has been taken to Kempsey Hospital and appeared to be suffering from minor injuries.
Kempsey Fire and Rescue crews have sprayed the contents of the truck with a glue and water spray to contain any possible airborne contaminants and are monitoring a diesel leak.
Salvage crews will arrive on scene later today to clear the accident.
The Pacific Highway northbound off-ramp at Macleay Valley Way is closed, traffic is being diverted to the next exit at Frederickton.
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