SOME 13 years after a preliminary environmental assessment was completed for the former Newcastle Gasworks site in Hamilton North, remediation works in the form of an underground barrier and a cap-and-fill are about to begin.
Like all gasworks sites, Clyde Street is contaminated with hydrocarbons, heavy metals, cyanide and more, left behind after 74 years of making flammable gas from heated coal.
A 2015 report by the Department of Planning and Environment, describes the problems as "extensive and widespread, including a range of toxic and carcinogenic contaminants that are present in the soils and groundwater".
The original environmental assessment from September 2006 says the main form of decontamination would be "thermal desorption", a method of heating hydrocarbon-contaminated soil in a way that does not release otherwise dangerous dioxins.
AGL sold the 7.4-hectare site the same year, 2006, to Jemena, a gas and electricity business owned 60/40 by Chinese and Singaporean interests.
The 2015 report still cites thermal desorption as "the preferred method" of remediation, noting "it has been used successfully in NSW to treat similar sites and contaminants".
Indeed, one of the pioneers of thermal desorption is University of Newcastle chemical engineer Dr John Lucas, whose Innova Soil Technology completed a successful trial on a heavily contaminated section of the BHP steelworks site in 2003.
Saying that the cost was too high, the NSW government (the site owner since 2000) then opted for a cheaper method - a cap and fill, coupled with a deep underground wall on three sides to stop the generally northerly flow of groundwater off the site.
Somewhere between 2015 and now, Jemena decided to follow suit.
Announcing the start of a site remediation it expects to finish by July next year, the company says it is spending about $11 million to level and cap the site, and to install a 510-metre "subterranean barrier wall ... to redirect groundwater flow around areas of contamination".
While such a method will allow for a new industrial site, it is not enough to permit residential use.
What's more, the contaminants will stay there, another legacy for future generations to deal with.
While you're with us, did you know Newcastle Herald offers breaking news alerts, daily email newsletters and more? Keep up to date with all the local news - sign up here.