Authorities are struggling to determine how to tackle a chemical blaze at an electrical plant north of Newcastle.
NSW Fire and Rescue crews are at an electrical plant at Tomago near Port Stephens where the facility's machinery overheated just after 5am on Friday.
Firefighters are unable to extinguish the blaze with water due to the risk of sparking an explosion.
There is an exclusion zone in place following the explosion risk.
This fire emergency could now stretch into Saturday.
