A large fire in the early hours of Tuesday morning has destroyed an industrial building in Penrose, Auckland.
The fire at the Neilson Street site created potentially toxic black smoke which saw Fire and Emergency NZ (FENZ) urge residents in Onehunga, Māngere Bridge and Favona to stay inside.
At 8am FENZ said the threat of the toxic smoke had dissipated and the fire had been contained.
FENZ said the building owner advised them that there is no asbestos or other hazardous substances in the building.
Firefighters were called to the scene just before 2am with more than 100 fighting the blaze.
At 8am there were four fire engines and around 25 firefighters at the scene.
Fire and Emergency incident controller Martin Campbell told 1News the fire was a "very rapid, very quick-spreading fire" which "could have potentially gotten away much, much quicker than it did" and spread to nearby buildings if they had to call on fire trucks from further afield.
He said it was "a bit nerve-wracking" tackling the fire "when you hear the boom and see the fireball go up in the air".
“I did hear a couple of reports of the 44-gallon drums exploding and shooting up in the air but thankfully, they landed safely away from any firefighters and any buildings.”
Witnesses said explosions could be heard in the area around 3am.
The school day at Māngere Bridge School and Te Papapa School was initially affected by the smoke. They later told students after the smoke had dissipated that they would be open around 9am.