Sydneysiders can thank a man named Glen for making sure the crane that caught fire on Tuesday didn't topple on bustling Broadway.
The operator of the crane, named only as Glen, appeared shaken when he told Channel Ten: "The fire just began ... just started.
"I got down. I tried to extinguish it, but it needed more than an extinguisher."
It's believed Glen, who is employed by Lend Lease, swung the arm of the crane around so it fell on scaffolding, away from the busy road below.
CFMEU state secretary Brian Parker said it was lucky that no one was injured or killed when the crane caught fire on the construction site at the University of Technology on the corner of Broadway and Wattle Street at about 9.45am.
"If this crane was pointed out on the street ... and it caught fire there could have been hundreds of innocent bystanders killed here today," he told reporters on Tuesday.
"That jib could have collapsed onto the road. It could have been motorists, it could have been pedestrians ... It's just by chance that it wasn't facing that way when it's caught fire."
A NSW Fire and Rescue spokesman said on Wednesday morning fire investigators had been unable to access the crane cabin because of stability concerns.
WorkCover is leading the investigation into the crane collapse.
"This is an extremely serious workplace incident and it is fortunate no one was injured or killed," WorkCover said in a statement.
"WorkCover inspectors are now on site investigating how the collapse occurred and will ensure the crane is stable prior to any recovery work."
It is understood the crane is owned by a Sefton company, Marr Contracting. It was then leased to Lend Lease, which employed the driver.
On Wednesday morning Wattle Street in Ultimo remained closed between Broadway and Thomas Street.
"There is no definitive forecast as to when the road will be fully reopened due to safety concerns," the Transport Management Centre said.
The slip lane from Broadway is open, so eastbound motorists can turn onto Wattle Street, but there is no access for westbound motorists.
Drivers are urged to be cautious, expect delays and allow extra travel time.
Mr Parker said workers had complained three weeks ago about the crane leaking oil, which was dripping onto their hard hats and clothes. The union asked Lend Lease to investigate the problem.
Lend Lease released a short statement confirming that a full investigation was being undertaken. "We are working closely with relevant authorities and unions to evaluate the incident," said Christian Sealey, the company's corporate communications manager.
He said the UTS site was regularly audited to ensure on-site safety.