Firefighters are currently on scene battling a rubbish fire at the Singleton Waste Management Facility.
The blaze has also sparked a small grass and bushfire in the surrounding area, which has since been successfully contained.
Smoke from the incident is visible across parts of Singleton, with residents downwind advised to close windows and doors and avoid exposure to the smoke where possible.
A significant number of firefighting resources remain on site as crews work to bring the fire under control and extinguish it as quickly as possible.