Explosions, fire at construction site in Circular Quay

 It appeared the fire was on the scaffolding of the building.  Photo: Supplied

It appeared the fire was on the scaffolding of the building.  Photo: Supplied

Thirteen people were treated for respiratory problems as dozens of fire fighters battled a major demolition site fire that sent plumes of smoke into the sky over Circular Quay.

Workers and commuters heard multiple explosions as the old Gold Fields House building went up in flames at the corner of Pitt Street and Alfred Street shortly before 9am on Tuesday.