City of Newcastle could face a potential multi-million dollar clean-up bill if it is found liable for historic contamination at the former Waratah gasworks site.
The area bounded by Turton, Georgetown and Ellis roads is polluted with contaminants including cyanide, lead and benzo(a)pyrene, a legacy of a former municipal gasworks that was decommissioned almost a century ago.
In addition to pollution, at least one house has been shifting on its foundations as a result of an old gas holder underneath it swelling and shrinking during wet and dry weather.
Cleaning up the site is likely to be significantly complex and expensive due to the fact that 20 properties have been built on or near the footprint of the former gasworks.
The project involved the installation of a 510 metre subterranean wall to redirect groundwater flow away from contaminated materials.
Liability for contamination at the Waratah site is due to be resolved in the new year, with the council's most recent financial statements listing the site as a 'contingent liability'.
"Legal responsibility is yet to be determined and no definitive position has been provided by the EPA," the council's statement says.
Despite that the council said last week it was confident it was not responsible for dealing with the historic contamination.
"City of Newcastle has always maintained that this matter is the responsibility of the state government," a council spokeswoman said.
"The Environment Protection Authority is working through the process to confirm this and we expect positive news in the new year."
But the EPA was less emphatic about where responsibility lay.
A spokeswoman said the authority believed the contamination was significant enough to warrant regulation under the Contaminated Land Management Act 1997.
"The EPA is yet to finalise where responsibility for the contamination lies but expects to resolve this in early 2021," she said.
"The EPA is working to ensure remediation of the site occurs."
NSW Health has provided precautionary dietary advice to residents living on the footprint of the former gasworks in relation to home grown produce and exposure to soils and hygiene practices.
The health authority has asked that the precautionary dietary advice remain in place for the eastern portion of the gasworks site until mitigation measures have been completed and validated.
Turton Road resident Adam Lowe unwittingly came across part the suburb's toxic legacy in mid-2016 when a crowbar he was using to install a pool with vanished down a hole.
The hole was later identified as an old gas holder.
The deteriorating structure was estimated at around 18 metres in length and ran the length of the house and backyard.
It was also blamed for cracks in fences, a leaning side wall and brickwork that was pulling away at the base of the house.
"When it fills up with water ... everything in the tank becomes soft. Then the structure dries out and hardens. That causes the structural damage we have now," Mr Lowe told the Newcastle Herald at the time.
"You can repair the structural damage now, but in 20 years you'll have more structural damage because the problem isn't solved."
Mr Lowe and his wife Kim, who had been living at their property for over two decades, told the Herald they did not wish to move away.
But they argued any solution would need to solve the problem "once and for all".
"We'd hate to think there'd be more deterioration in the house in years to come," Mr Lowe said.
City of Newcastle does not hold administrative records for the former gasworks, which was operated by the former Waratah Municipal Council.
The plant was decommissioned in 1928.
More than 300 soil, vapour and groundwater samples were collected by an independent consultant as part of the council's 2017 investigation.
Cyanide, lead, chromium, polycyclic aromatic hydrocarbons (PAH) and benzo(a)pyrene were found above the screening criteria in the yard of a Turton Road property.
The latest research shows lead exposure can impair intellectual development in children, while benzo(a)pyrene has been classified as a group one carcinogen by the International Agency for Research on Cancer.