The fire remains very much alight late into the night, however authorties say it's contained with no risk of further spreading.
At 3pm today, emergency services were called to reports of a fire at the Transgrid Substation at Yallah on the Princess Highway, approximately 5km south of Dapto.
It is believed more than 100,000 litres of oil has caught alight, which could see the blaze burn for three to four days.
One transformer is fully alight with a second transformer at risk.
A total of 16 trucks and 60 firefighters are battling the flames, but no injuries have been reported at this stage.
"Due to the smoke being considered toxic, affected residents are urged to stay indoors and secure all doors and windows," a spokesperson for NSW Police said.
"It is anticipated that it may be sometime before the fire is under control."
"We have shut down Albion Park Airport as the smoke plume is impacting the approaching aircraft," he said.
He said the situation is evolving but so far, emergency services are unable to extinguish the blaze.
"At this stage firefighters are unable to fight the fire until the confirmation power has been shut off by the electrical authority."
Transgrid, RFS as well as Fire and Rescue NSW are trying to establish the best way to extinguish the blaze.
One FRNSW crew is providing fire protection for the on-site specialists.