Victorian taxpayers will be hit with a massive clean-up bill for a West Footscray warehouse inferno that burned for days in 2018 after the Supreme Court ruled the property was not insured at the time of the blaze.

The fire at the sprawling West Footscray property in August 2018 was the biggest industrial blaze in Melbourne since the Coode Island disaster of 1991 and sent toxic smoke billowing over the city's western suburbs.

The warehouse was an illicit dump, packed with steel drums filled with millions of litres of toxic and highly flammable chemicals.

WorkSafe Victoria has estimated that remediation of the toxic site will cost at least $15 million, but the full extent of the contamination is yet to be determined almost 18 months after the fire.