The story of how the toxicity of so-called 'forever chemicals' was kept secret for decades while communities in the US were poisoned is dramatised in the Mark Ruffalo film 'Dark Waters'.
But the sequel is already being played out because the chemicals, collectively termed PFAS, are not just ever-lasting - they are everywhere. Scientists from NUI Galway have recently found them in breast milk, tap water, bottled water, and air and dust from inside classrooms, homes, offices and cars.
Where exactly they came from is hard to pinpoint because PFAS - used to make products waterproof, flame-retardant, grease-proof, stain-resistant and non-stick - are widespread.
Furnishings, cookware, food packaging, cosmetics, clothing, footwear and electronic devices, as well as fire-fighting foams and other safety equipment, all regularly have the PFAS treatment.
"Unfortunately, they're very good at their job and we've become very dependent on them," says Dr Ian Marnane, chemicals expert with the Environmental Protection Agency (EPA).
The unfortunate part is that cancers, thyroid disease, liver and kidney damage, raised cholesterol, immune system disorders and fertility problems have all been linked to the chemicals which never degrade and build up in ever greater concentrations.
A major conclusion from the Galway studies is that exposure to PFAS from the sources they examined, combined with intake from food where international studies show the chemicals accumulate most, could push people into the danger zone.
Research into the presence of PFAS in food here is scant, however. Some monitoring of levels in seafood is carried out but the Food Safety Authority of Ireland (FSAI) conducted its last testing of the wider household diet in 2010.
"There was not much human health concern at the time," says Dr Christina Tlustos of the FSAI, "but in the meantime, there have been new studies that show maybe these values were underestimated and the substances are more toxic than originally believed.
"We have started looking into developing methodology in Ireland, to see how we will develop a monitoring programme," she adds.
The European Commission is a main driver. It is moving to tighten controls on the use of PFAS and in the past week the European Food Safety Authority has also begun a consultation with industry, academics and environmental and public health groups to try to agree new 'safe' limits.
But that presents a major challenge to regulatory bodies here. PFAS - or perfluoroalkyl substances - are a collection of more than 4,000 chemicals, making monitoring tricky, particularly when there is little tradition of doing so.
Work to equip the State Laboratory and other key facilities such as the Dublin Public Analyst Laboratory to test for PFAS only began in the last year or so. Irish Water does not yet test for PFAS in drinking water, nor in the sludge from waste water treatment plants spread copiously on agricultural land.
"It is likely that these chemicals will be included in the revision of the EU Drinking Water Directive that is currently being negotiated in Brussels," a spokeswoman said, adding testing would then be mandatory here.
The EPA does not test for PFAS in soil or air and only began checking river and lake water for PFOS, a subset of PFAS, last summer despite European Commission advice to do so from 2013.
"Since July 2019 we took 300 samples from rivers and lakes at 48 sites," says Dr Ian Marnane. "We did find PFOS but there is an EQS, an environmental quality standard, and those sampled were within the required limits."
The target for this year is 500 samples and, over six years, to test all the main water bodies. But that's likely to be only the start of the task, Dr Marnane says.
"The European Commission has a watchlist of substances that they may want to add to the priority list in time so there could well be other PFAS substances that end up being included," he adds.
The EPA is also drawing up plans to begin testing at the sites of major fires and fire training exercises to check for ground contamination by PFAS from fire-fighting foams.
Dr Marie Coggins of the NUI Galway studies says certain groups of people should be targeted too. "It would be good to look at exposures among occupational groups, such as firefighters," she says.
The process of testing of PFAS sounds narrow, disjointed and overwhelming and Dr Marnane is not inclined to disagree. "There is a realisation right across Europe that they need to be assessed in a more coherent way," he says.