Since its closure in 1985 after 72 years of operation, the toxic wasteland sat abandoned for more than three decades.

Numerous studies confirmed the extent of the contamination across the 7.5 hectare area. One analysis revealed a range of carcinogens and toxic compounds including benzene, polycyclic aromatic hydrocarbons, cyanide, ammonia and lead.

In addition, some were already leaching into groundwater and posed a risk to human health and the surrounding environment.

Despite the growing liability, neither the site's former owner AGL or the state government showed any interest in undertaking a clean-up.

Jemena, which acquired the site in 2006, spent a decade preparing a plan based on a strategy of containing the majority of the toxic waste on site before capping it.

A similar process was used to remediate the former BHP site at Mayfield.

In the case of the gasworks site, a 510 metre subterranean wall was installed to redirect groundwater away from the contaminants.

While the remediation process leaves the land suitable for commercial and industrial purposes, some argue that it simply leaves the core problem for another generation to deal with.

This argument is particularly relevant given examples of containment cells that have leaked in as little as two decades of completion.

Conversely, if property owners were required to undertake remediation to the highest standard, it is likely that fewer industrial remediation projects would occur.

The cost of such projects would also inevitably be passed onto future occupiers of the land.

It is easy to understand Jemena's motivation for investing $11.5 million on the clean-up after it had laid idle for so long.

In addition to the cost of the clean-up becoming more expensive with every decade that passes, the site is strategically located adjacent to the Broadmeadow precinct.

The value of commercial property in this area is likely to rise sharply in anticipation of the realisation of the state government's Broadmeadow masterplan.

Hopefully this will mark the start of a new and productive chapter for the site that has been a negative legacy for far too long.

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