Data centres are becoming the backbone of the AI economy, but their environmental impacts extend far beyond soaring energy demand. Scientists and campaigners are now raising questions about a hidden and largely unregulated risk: airborne PFAS pollution from the facilities powering the digital revolution.
It’s here to cure cancer, take us to Mars, automate transport and drive energy efficiencies. On the flip side, it’s taking your job, stealing our water and making us doubt what’s real.
Endlessly divisive, nevertheless AI becomes more pervasive by the day, fuelling concerns over its insatiable appetite for electricity, thirst for H2O, and high noise pollution levels at the data centres needed to power its growth. The UK — already home to the highest concentration of these facilities in Western Europe — is now on the cusp of rolling out the next generation of hubs. Larger than ever, with impacts to match, the number of individual sites will increase by one-fifth during the next four years.
The US is further down that trajectory, and public pushback has become impossible to ignore. One survey by Gallup suggests 71% of adults don’t want such developments in their neighbourhood. Globally, the UN just called on governments to urgently include the huge resource demands of data centres into planning policy or risk exceeding the limits of their national resources, warning the world’s data centres will use more power than Pakistan, Bangladesh, and Nigeria combined by 2030, and consume more water than 1.3 billion people.
Late last year, American campaigners began asking about the risk of PFAS pollution posed by data centres. Also known as ‘forever chemicals’ because they can take up to 1,000 years to break down in the environment, more than 14,000 substances fall into this classification and large concentrations of many have been found in drinking water, the food chain, and our bodies, thanks to a range of sources. Public health risks include cancers, cholesterol, delayed childhood development, infertility, hormonal and immune system disruption.
Dr Shahir Masri, a specialist in air pollution exposure assessment and epidemiology at the University of California, Irvine, cites one Harvard study that found 10% of all PFAS used in Europe can be traced to the computing industry. Many of those substances can be released into the atmosphere as particulates. Some can attach to other compounds which are emitted as vapour. And it’s not unknown for a PFAS to form within our atmosphere through secondary chemistry when two or more precursor emissions react.
‘We see this all the time… Chemicals that create acid rain, for example, are not primary emissions,’ he explains. ‘Some of the most historically regulated pollutants in the United States are precursors to harmful chemicals rather than the chemicals themselves… I think there’s a lot less data on air related pollution in general when it comes to PFAS, just because of the notorious record these materials have for water and soil contamination.’
Dr. Jennifer Brandon is a PhD marine biologist who has spent over a decade conducting pioneering work on plastic and microplastic pollution, becoming a leading expert on contaminants which are invisible to the naked eye. After learning about our investigation into data centre PFAS emissions she began looking into the issue, and like Masri emphasises the lack of existing research and gravity of this collective oversight.
‘There’s a lot of PFAS being used in data centres,’ says Brandon. ‘They’re used in the production of the semi-conductors and microchips… A lot of centres swap these out every three-to-five years, creating a tonne of electrical waste with these chemicals in it… But one of the biggest ways they are involved in the industry now is through the systems needed to cool the data centres down. A lot of these immersion cooling systems are straight up PFAS or mostly PFAS.
‘That’s interesting because we are seeing so much community action about how these developments are impacting local water supplies, and these new cooling solutions are in many ways a response to that concern as they cut water consumption,’ she continues. ‘To know which is better in terms of impact — cooling by using high volumes of water, or PFAS, someone would need to do a thorough environmental study.’
As Brandon explains PFAS is also present in firefighting foam, although stocks of this type are gradually being phased out. And there is also a very real risk data centre PFAS pollution is happening off-site. For example, via the industrial smokestacks at plants producing microchips and semiconductors. But, again, it’s impossible to know how prevalent this is without effective measurement and monitoring. Worse still, even with such processes in place, being able to prove that a data centre or tech factory is responsible for forever chemical contamination is incredibly difficult.
‘Identifying causation is one of the biggest challenges. These chemicals are so widespread in our environment it’s really hard to get a control group. The same with microplastics: how do you find people with no exposure at all?’ says Brandon, before referencing a 2026 study by US toxicology experts at NMS Labs which looked at 10,566 samples. ’98% [of those people] had PFAS in their blood. These compounds have been found in the drinking water supply used by around 100 million citizens. About one-third of everyone in the US, which is why a lot of work started trying to clean up wells and other water sources.’
At the time of writing, there’s no such movement to tackle PFAS air pollution, something Brian Gross, partner at the law firm MG+M believes is due to a lack of knowledge about gaseous and particulate forms of these chemicals. ‘I just don’t think there’a a lot of awareness about PFAS in the air. Everything, even on the grassroots level, has been focused on water. There is obviously some momentum around regulating for greenhouse gases, and in the US some PFAS substances are covered there. [But] it’s been really about water until this point.’
Closer to home, both the EU and UK are introducing legislation aimed at reducing — and eventually banning — PFAS, and instead switching to ‘safer alternatives’ for specific purposes. Falling under the scope of the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), both jurisdictions are considered world leaders in this area of environmental policy. But new regulations don’t come into effect for another two years, during which time there will be a sizeable increase in the number and scale of data centres which are already online in Britain.
‘The big risk is the gap years until new PFAS regulation starts,’ says Arif Gasilov, Founder of sustainability and ESG consultancy Gasilov Group. ‘So it’s around two years from now that any atmospheric PFAS emissions from UK data centres will be covered by laws. Anything getting built right now that can use compounds which will be restricted in the future can do so freely, intentionally or not.
‘Every gram of PFAS that deposits from a data centre into the atmosphere, every bit that then comes back to Earth as rainwater, stays in the ecosystem permanently. Even if that concentration is low, it only goes in one direction. And there’s a lot of effort needed to clean these pollutants up, it’s very expensive,’ he continues. ‘That’s the problem: with anything else if you stop emitting the environment recovers over time, PFAS stays there, effectively forever, so every year without regulation adds to the overall burden.’
The lack of empirical evidence around PFAS exposure at and close to data centres, inside and outside, supports the idea that — as with their impact on water and energy — many developments are escaping the planning scrutiny they require. ‘They say less than 20% of Americans want data centres near their home,’ adds Gasilov. ‘But I don’t think that was factoring in chemical emissions at all.’
In 2024, the UK reclassified data centres as Critical National Infrastructure, meaning in most cases new facilities can be forced through by central government regardless of community objections or local authority decisions. However, approval still sits with councils until a forthcoming National Policy Statement arrives. Oliver Hayes, Head of Policy & Campaigns at Global Action Plan, explains the document will lay out the framework and considerations for approving data centres. Months overdue, he says some suspect the delay is down to Downing Street’s original, highly inaccurate environmental projections.
‘Even the smallest amount of interrogation of the figures they produced, which were hilariously small in terms of emissions associated with AI more broadly, prompted government to completely replace them with figures that were then 100 times higher,’ he says, emphasising how useless national modelling has been on the data centre impacts which are widely recognised and easily measured. Meanwhile, local planning teams have regularly revealed themselves to be under-educated on the implications of developments.
‘In West London, where there is a very significant cluster of data centres, three boroughs had to pause housing projects because they couldn’t get a grid connection — data centres were prioritised… The Greater London Authority is so worried about this it has published reports through the London Assembly Planning and Regeneration Committee,’ Hayes continues. ‘The authorities approved the plans because they just thought of them as warehouses, distribution centres. But the considerations are very different. To a degree I have sympathy for these officers who are not literate in what they are being asked to approve.’
When it comes to data centre air pollution, Hayes says the issue still flies under the radar, with attention focused mainly on greenhouse emissions from diesel backup generators and gas turbines. PFAS pollution may remain similarly invisible until comprehensive monitoring is introduced, allowing us to assess the scale of contamination and the generations it could take to reverse its health and environmental impacts.
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