Insights / News
Insights / News
In this article, Harry and Danielle explore the potential legal avenues available for bringing PFAS-related claims and the legal hurdles that prospective litigants might face.
PFAS (per and polyfluoroalkyl substances) are a large group of synthetic fluorinated chemicals. These man-made substances have unique characteristics which make them useful in a variety of industries: they can be exceptionally strong, heat resistant and repellent to water and oil.
The production of PFAS boomed in the 1940s, following the discovery of Teflon in 1938. Today PFAS are used in a variety of products including non-stick cookware, firefighting foam, medical devices and cosmetics.
There are two key categories of concerns related to PFAS: health and environmental. PFAS do not easily break down and some are known to build-up or bioaccumulate over time. PFAS have been found in rivers, fish, soil and food. Even rain in the Antarctic contains PFAS and almost everyone on the planet will have some level of PFAS in their bloodstream. The current costs to remove and destroy the total PFAS mass released annually into the environment would likely exceed the global GDP of 106 trillion USD (Ling, 2024).
This is all the more concerning given that the latest research suggest high levels of PFAS exposure is associated with an increased risk of cancer, developmental problems, immune dysfunction and fertility problems.
Despite increasing concern over the health impacts of PFAS, there is yet to be a wave of PFAS-related litigation in the UK. Potential routes for litigants could be to pursue claims in negligence, nuisance or under the Consumer Protection Act 1987 (CPA 1987). However, there will be significant hurdles to establishing each of these causes of action. Those hurdles and potential solutions are discussed below.
The first task for prospective claimants will be to identify a defendant against whom to bring a claim. However, the ubiquitous and persistent nature of PFAS means that in many cases it will be incredibly difficult to identify the source of the PFAS and therefore identify the appropriate defendant. Cases therefore will likely be limited to factual circumstances where the source of the PFAS is more obvious (such as where there is a clear source of the PFAS such as a chemical plant).
While PFAS are intentionally manufactured for use in consumer goods like non-stick cookware, in many environmental contamination cases, the PFAS causing concern is an unintended by-product or industrial waste stream resulting from a manufacturing process.
This raises a fundamental statutory hurdle: can industrial waste be classified as a “product” under the CPA 1987?
The answer is almost certainly no. Section 1(2) of the CPA 1987 defines a product as “any goods or electricity”. Because the statutory framework was designed to implement the European Product Liability Directive, it is aimed at defective items placed into commercial circulation. Manufacturing effluent or waste discharged into the air or groundwater lacks this commercial character.
Furthermore, even if waste could be construed as a product, a claimant faces the statutory wall of Section 4(1)(b) CPA 1987, which provides a defence if the defendant can show “that he did not at any time supply the product to another.” While selling a PFAS-treated consumer item constitutes a “supply,” accidentally leaking industrial waste into the local water table does not.
Consequently, a crucial distinction must be drawn:
For prospective litigants facing historic environmental exposure, this statutory gap effectively closes off the strict liability regime of the CPA 1987, forcing them back into the more demanding territory of common law negligence or nuisance.
Scientific understanding of the harms PFAS present to human health is still evolving, which creates significant litigation difficulties for prospective claimants. In order to successfully bring a claim in negligence for personal injury, the harm must have been reasonably foreseeable. A court will judge whether the harm was reasonably foreseeable based on the standard of knowledge at the relevant time (Roe v Minister of Health and another [1954] EWCA Civ 7). Consequently, a claimant may have difficulty establishing breach of duty, particularly in claims relating to historic PFAS exposure.
Similarly, s.4(1)(c)(e) CPA 1987 provides a development risks defence, which means a defendant can escape liability if the scientific and technical knowledge at the time was not such that the defendant might be expected to have discovered the defect when the products were under his control.
It is generally accepted that the defence must include constructive knowledge which a producer would have acquired at the time the relevant product was put into circulation, if by applying relevant accessible knowledge in the pre-market testing phase (prior to first circulation), particular knowledge would have been acquired rendering the defect discoverable. Were the position otherwise, it would allow a producer a blanket defence in respect of unknown risks because for the defence to have any application the relevant defect/risk must be in fact unknown at the time the product was put into circulation.
There is, however, considerable disagreement in jurisprudential circles as to the proper scope of the Defence. As Mildred puts it in his leading text, the difference is between a defence of “absolute undiscoverability” and “undiscoverability by reasonable means”.
In broad terms, the first analysis construes constructive knowledge widely: it asks whether the Defendant could in theory have discovered the defect. To do otherwise (so the argument goes) would be to import question of fault and negligence into the CPA’s strict liability regime. Thus the question on this analysis becomes: was there a testable hypothesis using technology available at the time the product was put into circulation? Support for this proposition is drawn from Commission of the European Communities v United Kingdom (C-300/95):
It must therefore be proved, in order to exclude liability on the part of the producer, that it was impossible, in the light of the most advanced scientific and technical knowledge objectively and reasonably obtainable and available, to consider that the product was defective. [1]
This also appears to have been the view of the Court of Appeal in Iman Abouzaid v Mothercare (UK) Ltd (Times, February 20, 2001):
There was no difficulty in discovering the defect by a simple practical test … No advance in scientific or technical knowledge … was required to enable that test to be carried out. The only reason that it was not carried out before … was that manufacturers (it seems) had not thought of doing so.
This passage suggests that the mere possibility of discovering the defect is all that is required to defeat the defence. Importantly, the court did not feel the need to grapple with the reasonableness or otherwise of having failed to conduct the test despite the producer’s invitation to do so. Further, the producer’s reliance on a database with no record of prior accidents (putatively evidencing the state of knowledge) failed to address the second criterion of the defence, viz. whether the state of relevant knowledge was such as to enable the defect to be discovered.
The contrary view however – “undiscoverability by reasonable means” has many proponents.[2] It is also perhaps more consistent with the famous example of the “Manchurian researcher” given in Commission of the European Communities v United Kingdom:
It is undeniable that the circulation of information is affected by objective factors, such as, for example, its place of origin, the language in which it is given and the circulation of the journals in which it is published. To be plain, there exist quite major differences in point of the speed in which it gets into circulation and the scale of its dissemination between a study of a researcher in a university in the United States published in an international English-language journal and, to take an example given by the Commission, similar research carried out by an academic in Manchuria published in the local scientific journal in Chinese which does not go outside the boundaries of the region.
In such a situation, it would be unrealistic, I would say unreasonable, to take the view that the study published in Chinese has the same chances as the other of being known to a European product manufacturer.
Mr Justice Burton took issue with this precise formulation preferring to view the “Manchuria exception” as better represented by “unpublished research”. But what is clear on both formulations however (so the argument goes) is that considerations of practicability apply.[3] If it would be “unrealistic” to fix the Defendant with liability even where someone has in fact already obtained the knowledge required to identify the defect then it must be so a fortiori where no one has done so but the mere theoretical possibility existed. The actual Manchurian researcher, after all, possesses concrete knowledge; a purely hypothetical test does not.
Nonetheless, there are specific PFAS which are now known or considered likely to be dangerous to human health. For example, PFOA (perfluorooctanoic acid) is classified by the International Agency for Research on Cancer as carcinogenic to humans, whilst PFOS (perfluorooctanesulfonic acid) is classified as possibly carcinogenic to humans. PFOA was the specific PFAS at the centre of a number of high-profile legal challenges in the United States, against multinational chemical company DuPont. In addition, as research around PFAS grows, it will be harder for defendants to argue going forward that they didn’t have adequate knowledge of the potential risks.
Another hurdle faced by claimants will be establishing that they have suffered an actionable personal injury and that this was caused by PFAS exposure. There are likely to be two different categories of claims: (a) claims where the litigant is seeking to prove negligent PFAS exposure led to a specific disease, such as a cancer; and (b) claims where the injury alleged is solely increased PFAS levels, for instance in the bloodstream. The issues are different and are discussed in turn.
Future claims may seek to argue that the relevant injury is a specific disease, such as cancer. In these cases, the causation issues will include being able to establish that PFAS are capable of causing the specific disease (“generic causation”) and that they did in fact cause the disease suffered by the claimant(s) (“individual causation”).
The difficulties of establishing causation in chemicals cases is clear from the recent Court of Appeal decision Holmes v Poeton [2023] EWCA Civ 1377. In that case, the claimant was diagnosed with Parkinson’s disease and alleged that his previous employer breached its common law and statutory duty by exposing him to unsafe levels of Trichloroethylene (“TCE”). The Court of Appeal allowed the defendant’s appeal, holding that the claimant was not able to establish generic causation; the claimant had only established that TCE was a risk factor in Parkinson’s disease rather than establishing that TCE could cause or materially contribute to the development of Parkinson’s disease [112].
This generic causation hurdle is further compounded by the sheer diversity of the PFAS family, which encompasses thousands of distinct compounds. While robust epidemiological data exists to link legacy compounds like PFOA and PFOS to some specific pathologies, the scientific literature for newer, short-chain alternatives remains sparse. Because English law requires proof that the specific agent in question is capable of causing the harm, defendants can readily exploit these gaps in the data. Furthermore, given that PFAS exposure is near-universal, isolating it as a standalone generic cause from background environmental and lifestyle factors presents a formidable statistical challenge for expert witnesses.
Further, even if the claimant is able to establish generic causation, they will still have to go on to establish individual causation. The conventional route for claimants is to establish that “but for” the defendant’s negligence the injury would not have occurred. This will be challenging in many cases such as cancer, where it is not possible to say with scientific certainty what the cause of the illness was. Litigants will therefore likely have to resort to arguing either that their exposure to PFAS materially contributed to their illness or that the exception established in Fairchild v Glenhaven Funeral Services Ltd [2003] UKHL 22 should apply and it is sufficient to show that the exposure materially increased the risk of the illness. Both these approaches are likely to be fraught with issues as the law on material contribution is in a state of flux, and the courts have been reluctant to expand the Fairchild exception beyond mesothelioma-type cases.
Moreover, Fairchild was designed to solve an individual causation problem: a tracking and identification gap where a single, uniquely dominant agent (asbestos) was known to cause the pathology, but science could not pinpoint which specific defendant’s exposure triggered the cellular mutation. In contrast, prospective PFAS claimants face a prior, more formidable hurdle: a generic causation gap. Because the diseases associated with PFAS (such as various cancers or immune dysfunctions) are multifactorial and occur commonly in the general population without any chemical exposure, a claimant must first prove that the specific compound is biologically capable of causing the disease at all—the exact barrier that defeated the claimant in Holmes. The Fairchild exception operates to bridge a gap in proof between multiple tortfeasors; it cannot be used as a tool to bypass a lack of robust epidemiological evidence establishing generic toxicity.
The most effective strategic move for claimants to maximise their chances of overcoming causation hurdles or to negotiate settlements may be the group action. In non-PFAS chemicals cases, claims have been most effective where there has been a significant group of illnesses and/or conditions, perhaps linked by a common geographical location or by employment at the same company. For instance, in the Corby Group Litigation [2009] EWHC 1944 (TCC) the claimants argued that birth defects had been caused in children as a result of the ingestion or inhalation of substances from reclamation works. The court found there was a ‘statistically significant cluster of birth defects between 1989 and 1999’ [884] and that the birth defect rate in Corby was higher during that period than in surrounding districts [915]. After this judgment, a settlement was reached with 19 families. In short, prospective litigants may want to consider group action if the circumstances allow.
In cases where a claimant seeks to solely rely on increased PFAS levels in their blood, there is likely to be an issue of whether this is an actionable personal injury. In Sweden, residents from Ronneby sued drinking water supplier Miljö och Teknik AB, after high levels of PFAS was found in the water supply. The case progressed to the Swedish Supreme Court, where the key issue was “whether the high levels of PFAS measured in the appellants’ bodies constitute personal injury” [28]. The majority found that high levels of PFAS in the appellant’s blood did constitute personal injury and Miljö och Teknik AB was therefore liable [31 – 32].
It is less clear that English law would adopt the same approach as the Swedish legal system. In the landmark decision Rothwell v Chemical & Insulating Co Ltd [2007] UKHL 39, the House of Lords held that the development of pleural plaques, which signalled the presence of asbestos, was not in itself an actionable injury because they “in themselves do not give rise to any harmful physical effects which can be said to constitute damage” [50, per Lord Hoffman]. Prospective claimants will therefore likely face an uphill battle establishing that elevated PFAS levels constitute actionable personal injury.
However, as Lee observes (JETL 2025, vol.16(2), 171), there is a dividing line between cases such as Rothwell, where there is no actionable personal injury and cases such as Dryden v Johnson Mathey Plc [2018] UKSC 18. In Dryden, the claimants suffered from sensitisation to platinum salts. This was an asymptomatic condition but could result in an allergic reaction if the claimants were further exposed to platinum salts. This change to the claimants “physiological make-up” was sufficient to constitute actionable personal injury [47-48]. Prospective litigants would therefore want to characterise their claim as comparable to Dryden and distinguishable from Rothwell.
Due to the persistent nature of PFAS, claims may relate to events which took place, or to products which were supplied, many years earlier. Potential litigants will therefore need to consider whether there are any limitation dates which will prevent them from bringing a claim. For example, claims brought under the Consumer Protection Act 1987 (CPA 1987) must be brought within 10 years of the date of supply (s.11A(3) Limitation Act 1980). This 10 year cut-off operates regardless of whether knowledge of a product’s defect was acquired at a later date. Consequently, the usefulness of the CPA 1987 as an avenue for litigation will be limited where the issue is historic PFAS exposure.
In short, there are currently significant hurdles for prospective litigants looking to bring PFAS related claims. Nonetheless, in specific factual circumstances negligence, nuisance or the CPA 1987 could provide possible avenues for legal challenge.
Perhaps because of the difficulties of bringing PFAS-related claims, the United States and Europe have been at the forefront of PFAS litigation to date. However, there have been developments to suggest that PFAS litigation may become more prevalent in the UK. In 2024, lawyers were instructed by Cleaner Bentham, after groundwater in Bentham, North Yorkshire was found with high levels of PFAS, believed to be linked to the production of firefighting foams. In 2025, a separate claim in Bentham was settled, with no admission as to liability.
The potential for PFAS related claims may also increase if the regulatory landscape changes. In April 2025, the Environmental Audit Committee launched an inquiry to address the risks of PFAS. There is an increasing pressure to improve the monitoring and regulation of PFAS. Should tighter regulation be introduced, then this may sidestep some of the legal hurdles discussed in this article, and provide an alternative avenue for legal redress.
Harry Lambert specialises in the areas of product liability, medical tech, clinical negligence, personal injury, and human rights law. He is also renowned for his expertise in group litigation claims relating to these areas.
Harry is a creative and inventive lawyer, at the forefront of thought leadership on issues of product liability in the digital age. He is also the Founder and Head of the Centre for Neurotechnology & Law, and his 12-part series on Neurotechnology and The Law has garnered academic acclaim, been translated into several European languages, and turned into a podcast run by the Italian equivalent of the Financial Times.
Danielle Watts ia pupil at Outer Temple Chambers. Prior to coming to the Bar, Danielle worked as a paralegal for a leading human rights law firm, where she assisted on matters including complex judicial review challenges, private law claims and the Covid-19 Inquiry. Danielle graduated from the University of Oxford with a First Class Honours in Jurisprudence. Her dissertation focused on issues relating to the disclosure of medical risks, and she maintains a keen interest in this area of the law.
To find out more about Harry or Danielle, contact Paul Barton on +44 (0)20 7427 4907 or Harry Gamble on +44 (0)20 7353 6381 for a confidential discussion.
[1] Para 26. NB this is the view of the Advocate General but that judgment was adopted by the ECJ and Mr Justice Burton accepted it as a correct statement of the law.
[2] See e.g. Miller & Goldberg, Product Liability, at 13.85-13.90; Jane Stapleton: Products Liability in the United Kingdom: The Myths of Reform (1999) 34 Texas International Law Journal 45,59; and Mark Mildred, ibid., at 2.82 et seq.
[3] See e.g. Mr Justice Burton’s use of the word “should” at Para 74.
Legal Blogs 4 Jun, 2026
Call: 2008
