Public health advocates have warned against official advice that asbestos sheeting had “burned up” safely after a West Footscray factory fire sent thick black smoke across Melbourne’s skyline.

About 100 fire fighters worked through the night on Thursday to bring the industrial fire under control, but the site continued to smoulder on Saturday afternoon.

While the cause of the blaze remains unknown, the Melbourne Fire Brigade said it had made the decision to hand the investigation to Victoria Police after determining the cause of the fire may be suspicious.

The Environment Protection Authority has warned residents to steer clear of Stony Creek after toxic water flowed into the waterways.

But the EPA and Melbourne Fire Brigade’s advice that the factory’s asbestos sheeting construction posed a “low risk” and the material had been consumed by the fire has been called “misleading” by some experts.

Melbourne Fire Brigade acting chief fire officer Greg Leach told the ABC  on Friday that “much of that asbestos is going to have been consumed by the fire in the early stage” because of the intensity of the fire.

Mr Leach acknowledged there was a chance asbestos had drifted into the air “but we think the heat of the combustion had been such that most of that risk had been ameliorated”.

Asbestos Council of Victoria chief executive Vicky Hamilton told The New Daily she had sought to contact the Melbourne Fire Brigade and the EPA following the assessment.

The New Daily has also sought comment from the MFB regarding the asbestos advice.

“I’ve never heard that myself … asbestos doesn’t burn up in fire, that’s why it was considered a good product [in the past],” Ms Hamilton said.

CFMEU occupational health and hygiene specialist Jerry Ayers told The New Daily there was no medical or scientifically acceptable level of asbestos exposure based on international research.

Dr Ayers said while a 1200 degrees Celsius blaze would change the characteristics of asbestos, asbestos sheets could often explode in a fire, blow up into the atmosphere and land 50-100 metres away from the site.

“There needs to be a good clean-up procedure implemented and a thorough inspection in the vicinity around the fire,” he said.

University of Western Australia professor of medicine and public health and respiratory physician Bill Musk told The New Daily he didn’t think asbestos was consumed in fires.

Professor Musk said asbestos was used for many years precisely because it was heat resistant, and its name is derived from the Greek word for “unquenchable”.

“In a fire or earthquake, asbestos fibres are liberated into the atmosphere and that’s why they’re so dangerous to us if breathed into the lungs,” he said.

“There are different sorts of asbestos, but there’s no safe level of asbestos and that’s why it’s been banned.”

An EPA spokesperson told The New Daily asbestos burned in the West Footscray factory fire had been deemed a “low risk” because of the “nature of the fire”.

“The EPA, as a matter of due diligence, will test for contaminants in the area,” they said.

“It’s considered a low risk, but tests will include asbestos.”