Loading Ford said it notified the NSW Environment Protection Authority, Strathfield Council and the developer after detecting a change in ammonia levels on the edge of the old landfill site in 2015. Those changes were "minor and still within acceptable levels", Ford Australia spokesman Martin Gunsberg said. He said further tests were recommended to detect any impact on the estate's land. "Since [2015] we’ve been in discussions with the developer and more recently, the owners’ corporation of Centenary Park about gaining access so we can further investigate the change at the shared boundary," he said. "At this point we don't know if the Centenary Park development is affected or not."

The authority wrote to the Centenary Park owners' corporation in January, informing them the authority intended to issue a preliminary investigation order directing them to get the site tested. Investigations had "confirmed the existence of elevated levels of ammonia and dissolved methane in the groundwater at the old landfill and elevated methane in ground gas at the old landfill". "The EPA suspects that the old landfill leachate is now migrating south from the old landfill and is potentially contaminating the [Centenary Park] site," the letter said. The vast Courallie Avenue housing estate previously drew criticism for traffic congestion and garbage removal problems. Credit:James Brickwood "The purpose of this order is to investigate the extent to which the site is contaminated with the leachate containing elevated concentrations of ammonia, formaldehyde, polyclyclic aromatic hydrocarbons, volatile organic compounds, semi-volatile organic compounds and landfill gases."

The EPA said that documents provided by Ford showed the motoring company and the owners and managers of the site had not been able to agree about access despite three years of correspondence. An EPA spokesman said there was no evidence "at the moment" to suggest the presence of any contamination on the Centenary Park development site. "The work required by the EPA is to investigate whether groundwater from the landfill is moving towards the Centenary Park development site and whether any contamination is present." He would not be drawn on any potential risks to residents associated with the chemicals detailed in the draft order. A Telmet Ventures spokesman declined to comment on the claims the developer had first been informed of the possible breach in 2015, and on the cause of the delay to Ford's access to the site.

Loading "We can tell you we were first informed that Ford had formed a suspicion that a landfill barrier had been breached when we received a letter from EPA dated 7 January 2019," he said in an email. "The matter is now the subject of detailed investigation by EPA and we will await their determinations before making any further comment." A Strathfield Council spokeswoman said the council could request the privately-owned estate's management to carry out tests but the property was managed by its strata company. "Our staff have been in talks with the Centenary Park strata in an attempt to have them allow access to the property, but this has been unsuccessful. [The] EPA is now handling it."

Centenary Park Management declined to comment. Strathfield MP Jodi McKay said it was "highly concerning" that most residents within the 1200 properties at the estate had only learned of the potential breach in January. She said there would need to be "a very good reason" why the authority and the developer hadn't acted sooner. "I think it is just appalling that there could be 2500 residents who've been exposed to very dangerous chemicals for four years," she said. The Herald spoke to several property owners who did not want to be identified but who voiced concerns that any contamination could negatively affect their property values or health. "Who is going to pay all these costs [for tests], is the concern of the community," one resident said.