Those properties, and six others in Epping and Campbellfield, have since been linked to a syndicate that is allegedly responsible for hiding up to 19 million litres of waste in rented warehouses.
By the time authorities inspected the sites in December 2018, the buildings were filled floor-to-ceiling with 44 gallon drums and plastic containers of highly-flammable solvents, aerosols, cleaning chemicals and paint.
Authorities only uncovered the operation as part of an investigation into the massive industrial blaze at a West Footscray factory in August last year that had been rented by the same operator, Wallan-based businessman Graham Leslie White.
Mr White has not been charged with any criminal offence but WorkSafe and Whittlesea council have issued dozens of improvement notices and emergency orders for the eight properties.
Another four other dumpsites have also been found in Craigieburn and Campbellfield in recent weeks, although it is unclear if they are linked to the same operation.
The independent review, which was ordered by the watchdog’s governing board, will also examine the effectiveness of the agency’s response to reports from the community and other agencies about the illegal storage and dumping of chemical waste.
In 2018, the EPA introduced a “central triage system” to ensure reports were followed up as a matter of priority.
The authority declined to comment on the Epping and Campbellfield dumping operations because they are currently under investigation.