The black dotted line shows the investigation area in Oakey, west of Brisbane. Credit:Defence Defence is continuing to test at Williamstown, and remains unsure how far the contamination may have spread, but made the point in its report that finding levels higher than the adopted screening criteria, did not necessarily equate to a higher risk. But while no one knows what health impacts, if any, the chemicals could cause, residents in both towns have been warned to avoid drinking bore water "as a precaution" by Defence and from consuming eggs, fish and milk from the impacted areas by state agencies. Town water in both areas is not affected. Blood test results recently returned to Oakey residents in Queensland's Darling Downs revealed levels of perfluoirnated chemicals (PFC), the same chemicals used in non-stick cook wear and water proofing sprays, of more than 40 times the national average.

In its information to residents, Defence has said that "while blood tests can provide a measure of PFOS, they are not recommended because they don't predict a level of health risks", but did pay for some Oakey residents to have their bloods done. Defence had been using PFCs, particularly perfluorooctane sulfonate(PFOS) and perfluorooctanoic acid (PFOA) in fire-fighting foams from 1970 until 2008. Defence's change in policy in regards to the chemicals it used followed growing international concerns some PFCs do not break down in the environment and the potential harm that could cause to living systems. Part of a growing list of "emergent contaminates", not enough testing has been done on PFCs in big enough samples to confirm any conclusive impact to human health, but at the same time, the potential for adverse health impacts has also not been excluded.

Laboratory experiments on rats have shown exposure to the same chemicals showed "some potential to promote cancer", but it remains unclear how that translates to human health. Other potential, but unproven health impacts from inconclusive international studies involving people included kidney and liver issues. Defence undertook an environmental audit of the area around its Oakey base in 2010, five years after it stopped using the PFC fire-fighting foams in its training exercises and discovered PFOS and PFOA in the groundwater beneath its base and seven years after it was warned use of PFOS should be restricted and not used for training purposes. Following the 2010 results, Federal personnel conducted further tests and discovered in early 2014 the contamination had spread beyond the base into water bores used by local land holders and Oakey Creek. That same year, Oakey residents were advised by Defence to avoid drinking bore water, even if boiled. Residents have been told that of the 112 bores tested by Defence in the Oakey area, 42 had levels which exceeded the health advisory drinking limit. About 4500 people live in Oakey, with many relying on bores for their main water usage, with connection to the town supply, which comes from the regional centre of Toowoomba, often considered too expensive.

Defence has begun supplying drinking water to some residents who live nearby the base on a "case-by-case basis, but despite the area forming part of the Darling Downs food basin, has said it has no information "which indicates that using groundwater for watering stock and irrigating crops, including for commercial purposes, should cease". But Queensland Health is understood to be taking the warnings a step further, advising residents not to eat eggs, or drink milk from animals raised within the contamination zone, as well as avoiding fish caught in the creek, advice which echoes that of the NSW EPA and Health departments, following the discovery of the chemicals earlier this month, around the Williamtown RAAF Base and Newcastle Airport. Residents have also been warned to avoid preparing food with the ground water and in NSW, not eat oysters or prawns from impacted creeks, with commercial and recreational fisheries and oyster harvest closed in early September for up to one month, as a precaution. Restricting exposure to PFCs can lead to levels of the chemicals in blood, decreasing over time. An AECOM land contamination specialist has warned that watering vegetables and using the bore water for washing laundry potentially also risks further exposure to the questionable PFCs.

Defence has warned residents the investigation into potential health and land impacts, if any, could take years. But it has so far declined to provide compensation for loss of income to Oakey business owners/operators for loss of income, or other losses from the contamination, and said it "does not have any information at this time, which indicates that values of the properties within the investigation area have been diminished". "This is a long-term environmental investigation and assessment," information provided on the Defence website states. "The information collected by Defence will assist it to understand the groundwater impacts and develop appropriate management strategies in relation to any potential human health and ecological risks." Toowoomba mayor Paul Antonio said while he was concerned about the impact of the chemicals, he was satisfied with the army's response.

"They've identified the problem and they've quantified the problem," he said. "They're the ones who have taken the initiative. "While we're not involved at the coalface of this, but what I am seeing is the army being proactive in pursuing the issue." Cr Antonio said the army was a vital part of Toowoomba's economy, so he did not want to "say too much" publicly. "There's two bases very close to town and both those bases are important to our economic profile and, quite frankly, what I've seen from the army is they're there to solve the problem," he said.

But some residents in the Queensland town have already begun raising concerns. Shine Lawyers has begun acting for about 50 landholders in the immediate vicinity of the Oakey base. Partner Peter Shannon said there was the potential for the entire town to be impacted. "One of the problems is that by merely coming out and telling everyone not to drink the water, the Army has more or less ensured that people close to the base would experience devaluation," Mr Shannon said. "They say they did that on a precautionary basis, but it's had an immediate effect – I mean, you try selling a block of land beside the army base in Oakey right now. "The uncertainty of the taint is enough, so that is the first and most obvious [issue] – the second is that people have elevated anxiety levels due to concerns about their health.

"We've had a number of blood tests come back that do show elevated levels and those people are understandably concerned and they want some action to keep monitoring their health." But Mr Shannon said while the community would like to see things "moving quicker", it was important communication between Defence and those impacted, remained open. "Defence is charged with the protection of people," he said. "It's obvious that there has been nothing malicious or intentional about how this problem has come about. It is a community issue that needs to be handled in a way that is sensitive to the needs of the community, especially given the parties we're dealing with. "In some cases, it is the employees of the army itself that have been exposed and a lot of the people in Oakey have very close ties to the Army so they are looking to not drag them through the courts, but to promptly develop a way of resolving their concerns as quickly as possible.

"For some residents, this is everything to them. It's their whole life that's invested in their land. They can't sell their properties, they're getting on in years and what's their future? "The army has an opportunity here to minimise its damage and it really has a social responsibility to do that without putting residents through the wringer to get justice." The Defence Force has been contacted for comment and was developing a response. But the discovery of the leaching at the New South Wales base has concerned Queensland Government sources who spoke to Fairfax Media about the potential national impact. "The fact of the matter is, we don't know and they don't know, what this stuff can do and how far spread it is," one said.

"That's what has us concerned. We just don't know." - With Cameron Atfield