At the same time, it spewed millions of litres of toxic chemicals into surrounding properties and waterways.

Now in a major breakthrough in the fight to have Truegain's toxic legacy contained, the heavily contaminated waste oil refinery will be demolished and site remediated at an estimated cost of $20 million.

The Newcastle Herald can reveal that NSW government has acquired the Kyle Street industrial site that was abandoned after Truegain went into liquidation in September 2016, just months after it was caught by Hunter Water releasing toxic firefighting foam chemicals, or PFAS, into the sewer.

Notorious for flooding in heavy rain, the property contains dozens of ageing and leaking tanks containing toxic waste, a large underground storage tank contaminated with PFAS chemicals and a cracked concrete spill containment area.

NSW Environment Minister James Griffin said the remediation would be completed in two stages, with all structures demolished and waste removed, before work begins on soil and groundwater remediation.

"The shocking pollution at the Truegain site was one of the cases that led to the NSW government's recent legislative changes, which will help ensure similar circumstances are prevented in the future," Mr Griffin said.

"Repairing environmental contamination is a lengthy process that can take years to rectify and can cost millions of dollars, which is why we gave the NSW EPA greater powers to prosecute those that cause land contamination or illegally dump waste. The new powers force those responsible for contamination and pollution to clean it up or manage it into the future, and not just walk away."

The law reforms were sparked after former environment minister Matt Kean visited the Truegain site in 2020, demanding the EPA throw the book at those responsible. Former landowner and Truegain director Bob Pullinger side-stepped a mass clean-up of the industrial site. Pullinger was fined, convicted and ordered to pay the EPA more than $1.2 million, to help cover the costs of the site clean-up, but declared bankruptcy in October last year.

Criminal proceedings for his alleged failure to comply with a clean-up notice issued by the EPA, and a prohibition notice issued by the minister, are currently before the Land and Environment Court.

Planning Minister Anthony Roberts said Property and Development NSW had taken control of the site and would manage the remediation, under the guidance of the EPA.

Truegain, also known as Australian Waste Oil Refineries (AWOR), closed its doors in late 2016. The organisation recycled a range of materials at its Rutherford site since the 1990s and was made up of two companies. Truegain dealt with contaminated water, while AWOR handled waste oil and processed fuel.

The Newcastle Herald's Dirty Deeds investigation revealed in 2018 that Truegain secretly pumped millions of litres of toxic waste into nearby creeks or dumped it on the ground over decades. More than 40 former workers told how the company would routinely use the property and surrounding waterways as a dumping ground for waste collected from industrial yards, airports, service stations, mines and car washes.