A bus has been sliced in half by a crane which fell from a construction site into a depot in Leichhardt.
The bus driver and another worker escaped with only minor injuries.
Brian Parker from the CFMEU says it could have been much, much worse.
"The boom landed less than eight inches away from some LPG tanks, where the buses refuel," he told LIVENEWS.com.au.
"We could have had a major disaster here today if that boom had actually gone into those tanks."