IT is the great unknown for people caught up in the Williamtown contamination scandal - what are these chemicals doing to their bodies?

NSW Health has refused blood tests, despite pleas from residents and the recommendations of a Senate inquiry. The refusal has raised eyebrows with American experts who say blood tests are vital to determine what people have been exposed to.

Michael McGowan and Carrie Fellner report.

JULIE Bailey is a mother first.

So while she’s upset about how the Williamtown contamination scandal is affecting the small community she lives in, and is furious at the way the Defence Department has handled the mess, her children are the reason she can't sleep at night.

In the eight months since she was told that chemicals from the Williamtown RAAF Base may have contaminated the water on her Salt Ash property, Ms Bailey has worried about what might be in her children’s blood.

At the heart of her distress is the NSW Health Department’s hard-line moratorium on blood tests for residents who live in the so-called contamination red zone.

Last year the health department issued advice to general practitioners stating that blood testing provides “no useful information about risk to an individual’s health”, and in cases where they have been done “the likely levels, duration of exposure and the small size of the population potentially affected limit its scientific and clinical value”.

It meant that any Williamtown resident who wanted to know the level of perfluorooctane sulfonate or perfluorooctanoic acid in their blood has been forced to pay $550 plus $30 GST to the National Measure Institute in Sydney.

The move – which has been criticised by members of all three major political parties – was a startling departure from previous cases where people had been exposed to the contaminants.

In Oakey, a small Queensland community a few hours west of Brisbane, Defence itself paid for blood testing when residents were found to be exposed to high levels of PFOS and PFOA.

Despite that, the department has eagerly adopted NSW Health’s position.

In evidence to a Senate inquiry into the contamination in December, Defence doctor Mathew Klein said the testing was “not a good idea” because it created “a very high level of anxiety”.

And it’s not only Defence that has come on board.

The NSW position has since been adopted nationally after the body responsible for guiding the federal government’s response to environmental threats to public health published a statement in March recommending that people exposed to PFOS and PFOA not be given blood tests.

Wayne Smith, an epidemiologist and NSW Health’s representative on the panel that recommended the position, says blood testing would be “unethical” if it couldn’t offer certainty for the people tested.

“If you are living in the red zone you are exposed to above-normal levels, end of story,” Dr Smith said.

“A blood test will not tell you anymore than that [and] you’re talking about invasive tests that cause unnecessary angst.”

But for Ms Bailey, “the not knowing is worse”.

“It weighs so heavily that I am not in charge of protecting my children and that some person in some government body can stop me from finding out information,” she said. “This is wrong.”

Ms Bailey’s determination was so strong that late in April she saved up to pay more than $1000 for both of her children to be tested by the National Measure Institute.

More than three weeks later, as this article went to print, she had still not received the results due to what she had been told were “hold ups” with the tests.

For Mel Marshall, from Salt Ash, the tests are about knowing if her children are still being exposed.

"It's not a matter of not knowing what it means ... it's a matter of, in 12 months time if you did another test and it was higher, you'd have to say okay we're doing something wrong here.

"We need to be able to monitor it. We can't do anything about it, but we can keep monitoring the situation."

"If it was just us maybe we wouldn't worry so much, but when you can't get safe drinking water for your kids, it's a totally different situation."

While there is a general consensus that blood testing for PFOS and PFOA can’t determine a health outcome, where some experts disagree with NSW Health is in the other benefits of testing.

Eric Donaldson is a retired air force doctor whose property in Oakey runs alongside the base.

He arranged for initial testing on a small sample of the town’s residents in 2014 as a way of calming the fears of residents who had been told by a Defence official at a public meeting that the contaminants were the “new asbestos”.

What he found though when he received results was that the level of the contaminants in the blood of some residents was 30 to 60 times the Australian background level.

A Newcastle Herald investigation has discovered that government agencies in the United States have funded bio-monitoring projects in more than six states, including Minnesota, New York, California, Vermont, Alabama and New Hampshire.

In Minnesota, where PFOA and PFOS manufacturer 3M has its headquarters, the chemicals were discovered in drinking water close to its manufacturing plant in the early 2000s.

It prompted numerous studies into the spread of the contaminants, and the Minnesota state attorney’s office is pursuing the company in the courts.

In 2007 the Minnesota state government legislated a bio-monitoring project of populations in two counties east of Minneapolis.

The aim wasn’t to make links to health outcomes, but to find out whether the government’s remediation efforts were working.

Jessica Nelson, a epidemiologist with the Minnesota state Health Department, explains the purpose of the study as: “All the efforts made to bring down PFCs in the drinking water, did they work?”.

The first study in 2008 found the average exposure to PFOS was roughly two-and-a-half times higher than the background US population. Two subsequent studies on the same residents in 2010 and 2014 found that while the levels were still above background, they had dropped by more than half.

Dr Nelson’s comments echo a wider view in the US that differs with what has become the response to dealing with the contaminants in Australia.

Kyle Steenland, a leading American epidemiologist whose study of people exposed to PFOA is among the largest ever produced says he “doesn’t understand” why NSW Health won’t conduct blood tests on residents.

A professor in the department of environmental health epidemiology at Emory University's Rollins School of Public Health, Dr Steenland was one of three scientists who conducted tests on more than 60,000 Americans in the mid-Ohio Valley between 2003 and 2015.

The oft-cited study found “probable” links between PFOA and six diseases including testicular cancer, ulcerative colitis, kidney disease and high cholesterol. Dr Steenland said that once contamination was detected, blood testing was “the next logical step”.

“If you want to know what people are exposed to compared to what other people are exposed to the water doesn't tell you that exactly, but the blood does,” he said.

“We know what the national values are [and] you'd have a reference. I'd wonder whether people have levels slightly above background or five times above background and the water's not going to tell you that.”

For Trish McLuckie from Williamtown, knowing what’s in her blood is about the hope that she will understand what it means in the longer term.

“In the past I’ve had health issues including thyroid disorder, and I’ve also got auto-immune issues,” she said. “I guess it’s just a personal thing, that I would like to know what my levels are.

"Whether it does increase or … has any impact in the future.”

Greens Senator Lee Rhiannon, who helped establish an inquiry into the contamination scandal that recommended blood tests be given to residents, agrees with Ms McLuckie.

“They are attempting to argue that there is no direct causation between PFOA [and] PFOS and adverse health effects to avoid paying for blood tests,” she said.

“Direct causation is an irresponsible benchmark for serious action. The benchmark for serious action should be the fact that there is a proven link between these chemicals and probable adverse health effects.”

Part Three of The Foam and the Fury will be published on Wednesday.