Highway traffic in Narrabri was diverted for almost five hours yesterday after a heavy vehicle transporting ice cream overturned on the northern end of Tibbereena Street.
Narrabri police said the north-bound truck was negotiating the corner near McDonalds and KFC when it fell on its left side at 10am.
The 68-year-old Queensland driver did not suffer any major injuries.
Police are investigating the cause of the accident.
The truck was towing an insulated trailer.
Narrabri Fire and Rescue station commander Shane Bradford said the ice cream posed a major environmental hazard if it melted and entered the nearby river system, where it would strip oxygen from the water and kill marine life.
Nearby drains were blocked and Narrabri Shire Council was called in to break the load off the truck and dispose of the ice cream in landfill.