A fire was set off in sydney's CBD by a worker's blowtorch at a construction site. due to gas bottle explosions; many people were forced to evacuate. At 8.45am; the fire burned through a 10-storey building on a demolition site. Although the Fire & Rescue NSW put out the fire before noon; the accident took a significant toll on daily commute. According to Fire and Rescue NSW; investigators have now attributed the fire to a construction worker's oxyacetylene blowtorch. The fire was likely incited by stray embers emitted from the blow torch piercing through steel. The blaze rapidly expanded into the plastic mesh screening around the scaffolding. Neil Van der Hoek witnessed the accident from an opposite building. We could see flames through the kitchen window; there were two explosions; from gas bottles I think. We could feel the explosion through the window; said Van der Hoek. The plastic sheeting on the outside caught on fire and dropped down onto a forklift. 24 construction workers had to evacuate from the building on Pitt Street and 13 suffered from minor smoke inhalation. The fire had some challenges in that there were a number of gas cylinders on the building site that not only exploded during the height of the blaze but (others) were also affected by the heat; Fire & Rescue NSW Superintendent Andrew Ticehurst told reporters in Sydney. There was some significant dangers to the firefighters with the gas bottles exploding; as well as it being a building being under demolition; there (were) some concerns around how stable the building (was). Thousands evacuated into the streets from neighboring buildings. Due to ground-level smoke; the Circular Quay railway station was also closed temporarily.