Hundreds of people were forced to evacuate nearby buildings, after a burning crane collapsed on a construction site in central Sydney.
The crane operator managed to escape the blaze unharmed.
The massive construction crane caught fire shortly after 10am this morning.
It started in a 1000 litre diesel engine that powered the boom coming off the crane.
The blaze burned for approximately 15 minutes, and then the arm of the crane toppled, sending steel crashing down on top of a University of Technology building.
Police rescue and fire fighters were on the ladder when the arm came down.
Witnesses say they "scurried out like rats" when the boom came down.
Aerial firefighting machinery was standing by in case the blaze flared up again.
The Construction, Forestry, Mining and Energy Union (CFMEU) says it went through the entire site just three weeks ago.
The union says workers walked off the job after it discovered discrepancies, and what it say are diesel leaks in the actual crane.
One of Sydney's busiest streets was blocked off in both directions to car and foot traffic.
UTS Senior Deputy Vice-Chancellor, Peter Booth, says it's lucky no one was seriously hurt.
"It's one of those things that happens with construction sites," Booth said.
Lend Lease released a statement saying it is working very closely with authorities to rectify the situation.
The blaze broke out at the Faculty of Engineering and Information Technology construction project site.
WorkCover NSW has launched a full investigation and said in a statement that officers are currently on site.
"This is an extremely serious workplace incident and it is fortunate no one was injured or killed."
WorkCover is urging anyone with information about the crane's condition prior to the collapse to call 131050.