Emergency services have been called to a business premises in western Sydney this morning following reports three men are trapped at the site.
NSW Ambulance received the call at 8.45am, with it understood that at least two of the men are trapped in a tank at an ink factory in Auburn.
The men are reported to be between 30 and 40 years of age.
One man has been extricated and taken to Westmead Hospital with leg fractures.
Two others remain trapped and are believed to be in critical condition.
According to NSW Ambulance, the rescue will be "a complex operation and may take four or more hours".