A furore has erupted in the US over the Trump administration heading off a water contamination study that has implications for New Zealand.
The study concludes that firefighting foam chemicals pose a danger to human health at far lower concentrations than the current official safety levels in the US, Australia and New Zealand.
"The public, media, and Congressional reaction to these numbers is going to be huge," one White House aide said, in emails obtained by Washington DC news site Politico.
"The impact to EPA and [the Defense Department] is going to be extremely painful."
The aide added the federal public health agency that did the study did not seem to realise "the potential public relations nightmare this is going to be".
US President Donald Trump's Democrat opponents are now demanding the White House release the study, which had been due out in January.
The US is grappling with a spreading water contamination crisis from firefighting foam, and other sources such as Teflon, of the harmful and long-lasting PFAS range of chemicals which includes PFOS, PFOA and PFHxS.
Australia, and now New Zealand, are in much the same boat, with extensive tests going on of water sources around defence bases and airports.
"The emails make no mention of public health effects," Politico reporter Annie Snider, who broke the story, told RNZ.
"That's the reason this has got so much traction. This seems to be all about the Defence Department in terms of liability and on EPA in terms of culpability for having had a higher risk level before."
The US risk level in a health advisory for PFOS and PFOA was drastically lowered in 2016 to 70 parts per trillion, total, in drinking water - like 70 grains of sand in an Olympic swimming pool.
Australia and New Zealand adopted this same level last year.
But exposure at just one-sixth this level could be dangerous for sensitive individuals like infants and breastfeeding mothers, according to the Politico emails about the new study by the Centers for Disease Control and Prevention.
It suggests dropping the health risk level to 12 parts per trillion.
Ms Snider said even some Republicans were now speaking up.
"We know for sure that the Trump administration did weigh in with concerns about it.
"This is not an issue that has been acted swiftly on by any of our regulatory agencies and, to be fair, a lot of the science is still being worked on.
"We have multi-trillion-dollar needs for upgrades to drinking water and wastewater infrastructure and so there is, I think, legitimately some concern about adding an expense to that."
There is infuriation about PFAS and health closer to home, in response to an expert health panel's new advice to both the Australian and New Zealand governments.
It concluded there was still no evidence the chemicals damaged people's health, though that could not be ruled out either.
"My community in Williamtown are outraged," New South Wales federal MP Meryl Swanson told RNZ. "They're possibly some of the most informed about this suite of chemicals."
Williamtown is one of the three worst contaminated towns so far identified in Australia's investigation of PFAS chemical leaching.
The expert panel had played down the health risks and discounted any need for interventions based on limited research, she said.
"I don't think that's prudent, I don't agree with that. Some of that research, I understand, has been done by industry groups and I'm not completely satisfied that the health panel's findings are extensive as they need to be.
"Do we need a new panel that does a new report? Potentially," she said.
Two of the 12 reviews the Australian panel looked at were by Dr Ellen Chang who works for a US firm called Exponent.
A US lawyer Robert Bilott who has led successful lawsuits against PFAS contaminators, told RNZ that Exponent had provided paid testifying services to at least one PFAS manufacturer facing court action.
The Australian panel also looked at eight international reports in preparing its advice.