As a police investigation launches into a "suspicious" fire at an inner Melbourne factory, residents downstream of the blaze site are being told to avoid polluted waterways.
Much of Melbourne was under thick plumes of toxic smoke on Thursday after a fire began at the asbestos-ridden West Footscray factory which housed aerosol cans and 44 gallon drums containing grease, oil and acetone residues.
It took 17 hours to bring under control and needed more than 140 firefighters.
Crews were still on scene late Saturday, pouring water over the smouldering mess.
Chemical run-off has polluted water at Stony Creek and the Environmental Protection Authority says there's a "strong odour" coming from the affected water.
Fish and other river creatures have been washing up dead.
The EPA says it is monitoring water pollution and has issued a warning for locals and their pets to stay away from Stony Creek and the nearby Cruickshank Park.
On Saturday, investigators from the Metropolitan Fire Brigade referred their investigation to Victoria Police saying they believed the fire's cause "may be suspicious".
Victoria Police confirmed they had taken over the investigation but couldn't begin yet because the site was not yet safe.
The blaze caused significant disruption to the surrounding community on Thursday with at least 50 schools and child care centres closing.
