Chemicals, noise and what is left behind

From the paper “Beyond Planning Permission”

The full text of the relevant sections of the paper, with its own numbered notes. Note numbers match the paper.

8. Local Environmental Effects

Large facilities may generate:

• continuous mechanical noise;
• low-frequency vibration;
• construction traffic;
• visual impacts;
• air-quality effects from backup generation;
• waste heat.^115,116

Because many facilities operate continuously, night-time impacts require particular attention.

Research is also beginning to explore whether concentrated clusters may contribute to localised heat-island effects. Further evidence will be required before firm conclusions can be drawn.¹¹⁷

Chemicals of concern in construction and operation, including PFAS 'forever chemicals'

A further concern raised in relation to data-centre development is the use of hazardous chemicals, and in particular per- and polyfluoroalkyl substances (PFAS), often called 'forever chemicals' because their carbon-fluorine bonds resist natural breakdown and can persist in soil, water and living tissue for decades.

Three distinct uses arise in this sector, and this appraisal treats them separately because the evidence, and the appropriate response, differs for each:

• dielectric cooling fluids used inside some immersion-cooling systems;
• clean-agent fire-suppression gases used to protect server halls without water damage; and
• PFAS used far upstream, in the manufacture of the semiconductors that data centres run.¹¹⁸

On cooling fluids, the picture is contested.

3M, formerly the leading manufacturer of two-phase immersion-cooling fluids (marketed as Novec and Fluorinert, both PFAS), announced in December 2022 its intention to exit all PFAS manufacturing by the end of 2025, and single-phase immersion-cooling fluids, typically mineral, synthetic or plant-derived oils, are not PFAS.

However, a September 2026 survey by the Swedish chemicals watchdog ChemSec, reported by the Guardian, found that nine of the world's ten biggest PFAS manufacturers - including Chemours, Daikin, Arkema, AGC, Dongyue, Gujarat Fluorochemicals, HaloPolymer, Orbia and Syensqo - now plan to increase production, citing demand from AI data-centre cooling and semiconductor manufacture specifically. Only Archroma and BASF (the latter by 2028) were reported as moving away from PFAS. ¹¹⁹

On this evidence, 3M's departure from the market appears to be the exception rather than the industry direction.

This appraisal has not identified a published, site-by-site account of PFAS-based cooling fluid use, continuing or discontinued, across the UK data-centre estate, nor any UK-specific data on whether developers here are among those now placing orders with the expanding manufacturers identified in the ChemSec survey; both are accordingly genuine, and so far as this appraisal can establish, unanswered questions.¹²⁰

On fire suppression, the position is less reassuring than it may first appear. Data-centre fire codes generally specify clean-agent gases such as FM-200 (HFC-227ea) or Novec 1230 (FK-5-1-12) rather than water-based sprinklers or aqueous film-forming foam (AFFF), precisely because they are non-conductive and leave no residue on electronic equipment.

Under the broad structural definition of PFAS now used by the OECD, and increasingly by UK and EU regulators, these clean agents are themselves PFAS, distinct from the AFFF more commonly associated with contamination at airports and military sites.

This appraisal has not identified confirmed evidence that AFFF is in routine use inside operational data-centre halls specifically, and treats that particular claim as contested; the clean-agent alternatives that are specified, however, remain PFAS on the definition now in general regulatory use.^121,122

On semiconductor manufacture, PFAS use is well documented in photolithography and etching processes, but this occurs almost entirely outside the United Kingdom, principally in Taiwan, South Korea and the United States, and is a matter for the chip supply chain rather than for a UK or Welsh data-centre site itself.

This appraisal notes it as relevant context for the sector's overall PFAS footprint - and for the working conditions of people employed in chip manufacture, a workforce quite separate from the data-centre construction and operational staff considered later in this section - rather than treating it as a local environmental effect of any specific UK development.¹²³

On quantities, this appraisal has not identified any published figure - litres of cooling fluid, kilograms of fire-suppression agent, or any other measure - specific to UK or Welsh data centres, whether for an individual facility or in aggregate.

In the absence of that data, no reliable extrapolation of the quantities of PFAS-related chemicals likely to be needed to supply the possible future extent of data-centre development in England and Wales can responsibly be offered; any such figure would be speculation dressed as analysis.

What can be said is only that the underlying drivers - more facilities, larger facilities, and a continuing (if declining) reliance on PFAS-containing fire-suppression and, to a lesser and diminishing extent, cooling technologies - point toward greater rather than lesser aggregate use while that reliance continues, a directional inference rather than a quantified one.

On environmental release and water contamination, PFAS's defining property - persistence - is also what makes any release into soil or water difficult to remedy once it occurs.

PFAS compounds bioaccumulate in the food chain and are associated in the scientific and regulatory literature with a range of health effects at sufficient exposure, which is why drinking-water limits exist at all.

UK regulatory protection for PFAS in drinking water is currently uneven: the Drinking Water Inspectorate's January 2025 guidance for England and Wales recommends a cumulative limit of 100 nanograms per litre across 48 named substances, but this is guidance rather than a statutory duty, whereas Scotland has applied a statutory limit for 20 named PFAS substances since January 2023.

The EU's revised Drinking Water Directive imposes a statutory total-PFAS limit from January 2026, a protection now available to EU citizens but not, in equivalent statutory form, to those in England and Wales.

Once PFAS enters a water source, contamination can render that source unfit for drinking, agricultural or other uses for a period measured in decades rather than months, which is why prevention rather than remediation is generally treated as the only realistic policy response.^124,125

This appraisal has not identified any confirmed instance of environmental contamination traced to a UK data centre specifically, whether affecting the surrounding environment, nearby residents, or a water supply.

The best-documented example of PFAS harm connected to this broader industrial family - contamination near Chemours's Fayetteville Works manufacturing facility in North Carolina - is a chemical-manufacturing case, not a data-centre case, and should not be read as evidence of an established data-centre-specific risk. US commentators have nonetheless begun explicitly connecting the AI data-centre boom to PFAS use, including reporting in September 2026 and a campaign-group report published in July 2026; this appraisal has not identified equivalent UK-specific reporting or research making the same connection for data centres in England or Wales.

The absence of a confirmed UK incident is not, on its own, evidence that no risk exists, particularly given the limited reporting requirements on data-centre chemical use noted throughout this appraisal; it is evidence only that no such incident has yet come to light.^126,127

On the people most directly affected - those working in data-centre construction and operation, rather than those working in semiconductor manufacture considered above - occupational exposure to fire-suppression and cooling-fluid chemicals during installation, maintenance, testing and any accidental discharge is the pathway most directly within a UK employer's control, and the one for which UK health and safety law already provides a regulatory route, through the control-of-substances-hazardous-to-health framework.

This appraisal has not identified any published assessment specific to data-centre construction or maintenance workers' PFAS exposure, whether from the Health and Safety Executive or from industry, and treats that as a further, specific gap rather than an assumption that no risk exists.

On decommissioning, UK PFAS regulation is only now beginning to develop and is not yet focused on data centres.

The Department for Environment, Food and Rural Affairs published the UK's first dedicated PFAS strategy - the 'PFAS Plan' - on 3 February 2026, updated 17 August 2026, adopting the broad OECD definition of PFAS and committing to a 2026 consultation on a statutory drinking-water limit and to reforming UK REACH so that chemical protections can be applied in a way that is 'more aligned with our closest trading partners, especially the EU, by December 2028'; commentary from the chemicals-policy organisation ChemTrust has described the Plan as prioritising further research over immediate regulatory action, in contrast with the EU's more advanced timetable.

Separately, the Health and Safety Executive has been consulting on a possible UK REACH restriction on 'PFAS in Firefighting Foams' specifically, in two stages: an initial consultation on the risk-assessment case opened in August 2025, and a further consultation on the socio-economic case opened in July 2026 and closed on 7 September 2026, with HSE's opinion on the risk assessment already given ahead of that second-stage consultation and a government decision still awaited.

This is a consultation confined to firefighting foam rather than to the clean-agent suppression gases more commonly used inside data centres, so its eventual relevance to data-centre decommissioning, if any, remains uncertain.¹²⁸

This appraisal has not identified any published UK or Welsh guidance addressing what happens to PFAS-containing fire-suppression systems, or any residual PFAS-containing cooling fluid, when a data centre is decommissioned, refurbished or demolished.

Natural Resources Wales's own State of Natural Resources Report 2025 identifies PFAS as a contaminant of concern in Welsh waters generally, but neither that report nor any other published Natural Resources Wales or Welsh Government material identified for this appraisal addresses PFAS specifically in the context of data centres or their decommissioning; this appraisal treats that as a genuine and citable gap in Welsh environmental regulatory coverage, while noting that Natural Resources Wales's statutory remit and resources are matters beyond this appraisal's scope to assess.

As an illustrative, and deliberately non-comparable, order-of-magnitude reference point for the scale of liability that PFAS-specific remediation can generate once identified across a cluster of sites, the US Government Accountability Office reported in 2025 that the US Department of Defense's own estimate of its future PFAS-specific investigation and cleanup costs had risen to more than $9.3 billion for fiscal year 2025 and beyond, more than tripling since 2022; this figure is cited purely to illustrate how quickly such liability can grow once quantified, not as a claim that any comparable liability has arisen, or should be expected, from UK or Welsh data-centre development.^{129,130,131,132}

A more concrete illustration, and one now adjudicated rather than merely estimated, comes from New Jersey.

On 8 August 2026 a US federal court approved settlements totalling approximately $2.5 billion, payable over 25 years, between the State of New Jersey and DuPont-related entities (around $2.075 billion in total, combining an $875 million payment into funds for natural-resource restoration and drinking-water-system remediation with a further $1.2 billion in additional remediation commitments) and 3M (a further $400-450 million), arising from decades of PFAS manufacturing contamination in the state. ¹³³

This settlement concerns chemical-manufacturing sites, not a data centre, and this appraisal does not suggest that a comparable liability has arisen, or is likely to arise, from UK or Welsh data-centre development; but it is a materially firmer data point than the Department of Defense estimate above, since it reflects a sum a court has actually approved rather than an agency's own internal projection, and it involves two of the same companies - DuPont and 3M - whose PFAS products feature elsewhere in this section.

Whether the scale of liability that can attach to PFAS manufacturing, once identified, has any read-across to the manufacturers now expanding PFAS production for the AI and data-centre market identified above is, on the evidence available to this appraisal, an open question rather than one this appraisal is in a position to answer.

A question naturally arising from PFAS's multi-decade persistence is whether this issue has serious repercussions for the seven-generations principle underpinning the Well-being of Future Generations (Wales) Act 2015.

This appraisal has not identified any published material in which the Welsh Government, the Senedd or the Future Generations Commissioner for Wales has connected forever-chemical contamination to the seven-generations or long-term thinking duties in that Act.

The connection drawn here is accordingly this appraisal's own inference, offered because the reasoning appears to follow naturally from the Act's own stated purpose and from PFAS's documented persistence, and not because any existing Welsh policy document makes the link.

On its face, a chemical class capable of remaining in the environment for longer than a human generation, let alone seven, is difficult to reconcile with a duty to safeguard the ability of future generations to meet their own needs; but this appraisal is not aware of that reasoning having been tested, applied or even considered in any published Welsh Government, Senedd or Future Generations Commissioner material to date, and flags the point as an original inference requiring independent verification rather than as an established finding.¹³⁴

A suggested written question, which could be tabled by a Member of the Senedd to the Cabinet Secretary with responsibility for climate change and rural affairs, or put by correspondence to Natural Resources Wales, reads:

'What assessment has the Welsh Government or Natural Resources Wales made of

• the use of PFAS ('forever chemicals') in the fire-suppression and cooling systems of data centres operating or proposed in Wales, including the quantities used, the risk of environmental release, and
• what guidance, if any, exists on the safe decommissioning of such systems; and
• does that assessment have regard to the duties in the Well-being of Future Generations (Wales) Act 2015?'

No answer to a question in these terms has been identified in the Senedd Record or via WhatDoTheyKnow to date.

A request to Natural Resources Wales via WhatDoTheyKnow, seeking any risk assessment, monitoring data or decommissioning guidance specific to PFAS use at data-centre sites in Wales, would be a further and more direct available route, and has not, so far as this appraisal is aware, yet been made. The author believes that NRW’s involvement in regulating forever chemicals might be on the low side, at best.

A further written question, which could be tabled by a Member of Parliament to the Secretary of State for Environment, Food and Rural Affairs, reads:

'In light of ChemSec's September 2026 survey finding that nine of the world's ten largest PFAS manufacturers plan to increase production to meet demand from artificial intelligence data centres,

• what assessment has the Department made of whether the evidence base underpinning the PFAS Plan published on 3 February 2026 and updated on 17 August 2026 accounted for this trend; and
• does the Department intend to revisit the Plan's timetable for aligning with EU REACH restrictions, currently set at December 2028, in light of it?'

No answer to a question in these terms has been identified in Hansard or via WhatDoTheyKnow to date. A freedom of information request to the Department for Environment, Food and Rural Affairs via WhatDoTheyKnow, seeking any internal assessment of the ChemSec survey or of AI-driven PFAS demand more generally, could be a further and more direct available route, and has not, so far as this appraisal is aware, yet been made.

Notes from the paper

1. 115. House of Commons Library, Data Centres: Planning Policy, Sustainability and Resilience, Research Briefing CBP-10315 (27 May 2026). https://commonslibrary.parliament.uk/research-briefings/cbp-10315/
2. 116. House of Commons Environmental Audit Committee, Risks and Opportunities to the Sustainability of Data Centres in the UK (Inquiry, 2026). https://committees.parliament.uk/work/9651/risks-and-opportunities-to-the-sustainability-of-data-centres-in-the-uk/
3. 117. House of Commons Environmental Audit Committee, Risks and Opportunities to the Sustainability of Data Centres in the UK (Inquiry, 2026). https://committees.parliament.uk/work/9651/risks-and-opportunities-to-the-sustainability-of-data-centres-in-the-uk/
4. 118. 3M, '3M to Exit PFAS Manufacturing by the End of 2025' (20 December 2022), announcing the phase-out of all per- and polyfluoroalkyl substance (PFAS) manufacturing, including the Novec and Fluorinert product lines used as two-phase immersion-cooling fluids in some data centres. https://news.3m.com/2022-12-20-3M-to-Exit-PFAS-Manufacturing-by-the-End-of-2025
5. 119. Damien Gayle, "'Tidal wave' of Pfas being launched to satisfy AI industry, campaigners warn", the Guardian (14 September 2026), reporting a survey by the Swedish chemicals watchdog ChemSec of the world's ten biggest PFAS manufacturers, which found that nine plan to increase production, several citing demand from AI data-centre cooling and semiconductor manufacture specifically; only Archroma and BASF (by 2028) were reported as moving away from PFAS. This appraisal has not independently located ChemSec's own underlying report or survey methodology, and relies here on the Guardian's reporting of it. https://www.theguardian.com/environment/2026/sep/14/pfas-firms-tidal-wave-forever-chemicals-ai-industry-demand-datacentres
6. 120. Submer, 'PFAS Contamination: A Call to Action for the Datacenter Industry' (2026), describing PFAS as the chemical basis of two-phase immersion-cooling fluids and cautioning that, following bans on some PFAS formulations, manufacturers have in some cases reformulated products that remain PFAS under the broad definition while being marketed as 'green' alternatives. https://submer.com/blog/pfas-contamination-a-call-to-action-for-the-datacenter-industry/
7. 121. Organisation for Economic Co-operation and Development, 'Reconciling Terminology of the Universe of Per- and Polyfluoroalkyl Substances' (2021), setting out the broad structural definition of PFAS now generally used in UK and EU regulatory practice. https://www.oecd.org/en/publications/reconciling-terminology-of-the-universe-of-per-and-polyfluoroalkyl-substances_e458e796-en.html
8. 122. NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems, is the industry standard governing clean-agent gases such as FM-200 (HFC-227ea) and Novec 1230 (FK-5-1-12), chosen for data-centre use because they are non-conductive and leave no residue on electronic equipment; under the broad OECD definition of PFAS referred to above, these clean agents themselves fall within the PFAS family, distinct from the aqueous film-forming foam (AFFF) more commonly associated with contamination at airports and military sites. https://www.nfpa.org/product/nfpa-2001-standard/p2001code/nfpa-2001-standard-on-clean-agent-fire-extinguishing-systems-2015/200115
9. 123. ZVEI (German Electro and Digital Industry Association), 'PFAS and Semiconductors' factsheet, describing PFAS use in semiconductor photolithography (as photoresist surfactants and photoacid generators) and in plasma etching (fluorine-based gases used to structure silicon, dielectric and metal layers), and noting that no drop-in substitute currently exists for most such uses. https://www.zvei.org/fileadmin/user_upload/Themen/Nachhaltigkeit_Umwelt/PFAS/2-ZVEI-Factsheet-_PFAS_and_Semiconductors_-final.pdf
10. 124. Chemistry World, 'Water regulator applies stricter PFAS limits to drinking water in England and Wales' (2024), reporting the Drinking Water Inspectorate's guidance, expected to take effect from January 2025, introducing a cumulative limit of 100 nanograms per litre across 48 individual PFAS substances for England and Wales - guidance rather than a statutory duty, in contrast to Scotland's statutory limit for 20 named PFAS substances since January 2023. https://www.chemistryworld.com/news/water-regulator-applies-stricter-pfas-limits-to-drinking-water-in-england-and-wales/4020476.article
11. 125. Directive (EU) 2020/2184 on the quality of water intended for human consumption (the revised Drinking Water Directive) sets a total-PFAS limit of 0.5 micrograms per litre, which took effect across EU member states from 12 January 2026; the UK, no longer bound by EU directives following its withdrawal from the European Union, instead relies on the non-statutory Drinking Water Inspectorate guidance for England and Wales referred to above. https://environment.ec.europa.eu/news/new-eu-rules-limit-pfas-drinking-water-2026-01-12_en
12. 126. US Environmental Protection Agency, National Primary Drinking Water Regulation for PFAS (final rule, April 2024), setting enforceable limits of 4.0 parts per trillion for PFOA and PFOS, with public water systems given until 2029 to comply; the EPA's own 'Proposed PFAS Rescission Rule' and a related proposal to extend the PFOA/PFOS compliance deadline, both published in 2026, illustrate that this regulatory position remains contested and unsettled even in the jurisdiction that has gone furthest toward statutory limits, and are cited here as international regulatory context rather than as a statement of UK law. https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas
13. 127. Department for Environment, Food and Rural Affairs, 'PFAS Plan' (published 3 February 2026, updated 17 August 2026), the UK Government's first dedicated PFAS strategy, adopting the broad OECD definition of PFAS and committing to a 2026 consultation on introducing a statutory drinking-water limit and to aligning with EU REACH restrictions 'by December 2028'. https://www.gov.uk/government/publications/pfas-plan
14. 128. Health and Safety Executive, UK REACH consultations on 'PFAS in Firefighting Foam': an initial consultation on the risk-assessment case opened in August 2025, and a further consultation on the socio-economic case opened 9 July 2026 and closed 7 September 2026, with HSE's opinion on the risk assessment already published ahead of that second-stage consultation; a government decision on any restriction is still awaited. https://consultations.hse.gov.uk/crd-reach/uk-reach-restriction-on-pfas-in-firefighting-foam/
15. 129. US Government Accountability Office, GAO-25-107401, 'Persistent Chemicals: DOD Needs to Provide Congress More Information on Costs Associated with Addressing PFAS' (reissued with revisions, February 2025), reporting that the Department of Defense's own estimate of its future PFAS-specific investigation and cleanup costs had risen to more than $9.3 billion for fiscal year 2025 and beyond, more than tripling since 2022; cited here purely as an illustrative order-of-magnitude comparator for the scale and volatility of PFAS-specific liability once quantified, and not as a claim that any equivalent liability has arisen, or is expected to arise, from UK or Welsh data-centre development, for which this appraisal has identified no comparable costed assessment. https://www.gao.gov/products/gao-25-107401
16. 130. Natural Resources Wales, State of Natural Resources Report 2025, Pollution chapter, which identifies 'PFAS, veterinary medicines and other pharmaceuticals' as contaminants of concern in Welsh waters generally but does not address data centres as a source, and does not otherwise engage with PFAS in the context of data-centre construction, operation or decommissioning; this appraisal has not identified any other published Natural Resources Wales guidance, assessment or monitoring programme that does so, which it treats as a genuine and citable gap in Welsh environmental regulatory coverage rather than as an oversight necessarily attributable to Natural Resources Wales itself, whose statutory remit and resources are matters beyond this appraisal's scope. https://naturalresources.wales/evidence-and-data/research-and-reports/state-of-natural-resources-report-2025/pollution/?lang=en
17. 131. North Carolina Department of Environmental Quality, GenX Investigation: Groundwater, documenting PFAS/GenX contamination of industrial and residential groundwater wells near Chemours's Fayetteville Works manufacturing facility, first identified in 2017 and the subject of a February 2019 Consent Order; this is a well-documented example of PFAS harm linked to chemical manufacturing, not to a data centre, and this appraisal has not identified any confirmed instance, in the United Kingdom or elsewhere, of environmental contamination traced to a data centre specifically. Chemours agreed a further $450 million settlement covering Fayetteville Works and three other US sites in June 2026, illustrating that liability from PFAS-manufacturing contamination remains an active and growing matter even for a case dating to 2017. https://www.deq.nc.gov/news/key-issues/genx-investigation/groundwater
18. 132. Reporting has begun explicitly connecting the AI data-centre boom to PFAS use, including Jessica Corbett, 'Research Warns of Surge in Cancer-Causing Forever Chemicals From AI Data Center Build-Out', Common Dreams (14 September 2026), and Food & Water Watch, 'Toxic Mixture: Data Centers Turn to PFAS For Cooling' (July 2026). This appraisal has not identified equivalent UK-specific reporting or research making the same connection for data centres in England or Wales, which this appraisal treats as an emerging area of scrutiny elsewhere rather than as a topic yet addressed by UK press, regulators or campaigners in relation to domestic sites. https://www.commondreams.org/news/data-centers-and-pfas
19. 133. New Jersey Office of the Attorney General, 'Federal Court Approves Historic PFAS Settlements Valued at Approximately $2.5 Billion' (press release, 8 August 2026); see also the joint New Jersey Department of Environmental Protection news release of the same date, and reporting in the Philadelphia Inquirer, 'Federal court approves settlements that will pay New Jersey $2.5 billion for PFAS contamination' (8 August 2026), from which the breakdown of payments between DuPont-related entities and 3M given in the text is drawn. https://www.njoag.gov/federal-court-approves-historic-pfas-settlements-valued-at-approximately-2-5-billion/
20. 134. Welsh Government, Well-being of Future Generations (Wales) Act 2015: The Essentials. https://www.gov.wales/well-being-future-generations-act-essentials-html