UP to one in five petrol station sites may have leaked fuel and contaminated surrounding groundwater and soil. Cleaning up the sites once the business has closed can cost millions and take years.

There are fears dozens of former petrol stations abandoned or left derelict across Victoria pose a threat to human health.

Blackburn: Toxic time bomb? Credit:Angela Wylie

As Australia's petrol station industry shifted in the past decade to fewer but larger petrol stations, owners of small sites have locked up and walked away, leaving derelict and often contaminated sites across the state.

Some sites have been left abandoned for more than a decade, creating an eyesore, impacting on local amenity and posing long-term health threats with fuel contamination of the site and groundwater.