Police and investigators from Fire and Rescue NSW will comb through the wreckage of a former hat factory and another empty building that were engulfed in flames in the Sydney CBD.
Crews were called to Randle Street in Surrey Hills on Thursday afternoon to find the two multi-storey buildings completely alight.
Police arrived shortly afterwards to cordon off the scene, with nearby streets closed off and the eastern suburbs light rail line shut down.
Nearby residents were ordered to evacuate, as the fire sent plumes of toxic smoke into the sky.
The only reported injury from the fire was a minor burn suffered by a firefighter.
There was minor damage to nearby buildings, mainly from the extreme heat.
The fire was described on Thursday by Fire and Rescue NSW Acting Commissioner Jeremy Fewtrell as one of the largest fires in the city for years.
He said it was lucky no one was badly hurt in the extremely dangerous conditions.
The blaze saw 120 firefighters attend, with the fire declared mostly contained by around 7pm.
Fire investigators were on the scene to try to determine the cause of the blaze and police will also investigate.
