Forever Chemicals: Litigation, Liability and Insurance Coverage
12th Dec 2025
Andrew Rigney KC, Jamie Clarke and Hamish Fraser consider the potential for a new wave of litigation relating to pollution by ‘forever chemicals’, and the legal challenges that claims may face in tort and insurance law.
Introduction
- PFAS (per or poly-fluoroalkyl substances) is an umbrella term for a large group of synthetic, fluorinated organic chemicals. Due to the strength of their carbon-fluorine bond, PFAS exhibit extraordinary resistance to degradation, earning them the moniker, ‘forever chemicals’.
- PFAS chemicals have many useful properties and have been used globally since the 1940s. They are resistant to very high heat, protect surfaces from water, grease or friction, and have fire-retardant and stain-resistant properties. As a result, they have a wide range of uses in industry, everyday consumer products (for example in water-resistant fabrics and carpet, non-stick cookware, and food packaging), and in firefighting foams.
- However, it is that same quality of resistance to degradation that is now presenting increasing environmental and health concern. As it can take decades or even centuries for PFAS to break down, the chemicals tend to persist in air, water, and soil, and then accumulate in living organisms, in the food we eat, and in our bodies. PFAS can enter the human body through inhalation of indoor dust and air (from products such as furniture, carpets, and clothing), from consumption in food products, and even by absorption through the skin.
- Remarkably, PFAS are now so ubiquitous that studies have found measurable PFAS in the blood of nearly the entire population in developed countries[1].
- In addition, the scientific evidence associating PFAS exposure with adverse health effects – including certain cancers, liver dysfunction, immune system effects, and developmental harm – has grown substantially over the past two decades. Two PFAS chemicals, Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), along with their related compounds, have been classified as persistent organic pollutants (POPs) under the Stockholm Convention (listed in 2009 and 2019 respectively). These are chemicals of global concern due to their potential for long-range transport, persistence in the environment, ability to biomagnify and bio-accumulate in ecosystems, as well as their significant negative effects on human health and the environment. The manufacture, sale and use of products containing POPs is now banned.
- From a legal standpoint, PFAS chemicals present a classic “long-tail” risk. Their persistence means that contamination may emerge years or decades after use, raising complex questions of causation, foreseeability, limitation, and insurance coverage.
Global Litigation
- PFAS claims usually assert property damage and bodily injury resulting from soil and water contamination in connection with PFAS manufacturing processes. The US has been at the forefront of PFAS related litigation, with some cases showing the scale of the potential liability.
- In 2023, 3M Co reached a $10.3bn settlement with a host of US public water systems to resolve water pollution claims tied to PFAS forever chemicals. More recently, in New Jersey Department of Environmental Protection v. E.I. du Pont de Nemours and Co., DuPont and its affiliates agreed to a $2.5 billion settlement to resolve PFAS contamination claims across multiple sites in New Jersey.
- In South Carolina, there is an ongoing group-action litigation, re Aqueous Film-Forming Foams (AFFF) Products Liability Litigation, which has had approximately 10,000 associated cases opened since its inception. Plaintiffs generally allege that aqueous film-forming foams (AFFFs) containing PFOA and/or PFOS contaminated groundwater near various military bases, airports, and other industrial sites where AFFFs were used to extinguish liquid fuel fires. The plaintiffs allege that they were caused personal injury, a need for medical monitoring, property damage or other economic losses.[2]
- Apple is also facing a class action claim in North Carolina claiming that it knowingly sold smart watches containing harmful PFAS, despite being aware of the risks and citing them in a 2022 company document in which Apple committed to phasing out the use of these chemicals.
- Closer to home, in 2023, a class-action claim was brought by more than 2,700 residents in the Netherlands against DuPont, alleging that the company knowingly discharged PFAS that endangered public health from a plant operated since 1962. In 2022, the Belgian government reached a settlement with 3M in which the company agreed to pay $581 million in remediation costs, compensation, and fines as a result of its historical contamination of the ground around a manufacturing site in Zwijndrecht. PFOS was found in the nearby soil in 2018, and subsequently in the bloodstreams of local residents.
PFAS and Liability in England & Wales
- To date, it does not appear that any PFAS related litigation has been issued in England & Wales. However, it is understood that a group of concerned residents in the town of Bentham, North Yorkshire has instructed lawyers in relation to a potential claim against a local manufacturer of firefighting foams, which have historically been known to contain PFAS. In addition, a recent Environment Agency report has identified more than 10,000 ‘high-risk’ sites contaminated with PFAS in the UK. Likewise, a report from earlier this year found that to clean up the existing legacy of PFAS contamination in the UK alone will cost at least £9bn over the next 20 years. One imagines that it is only a matter of time before litigation arises.
- It is also notable that the global litigation trend in this field has been towards mass tort group-action claims, a type of litigation that is becoming increasingly common in England & Wales.
- There is a range of potential causes of action which could potentially arise against manufacturers of PFAS.
- Manufacturers and producers of PFAS will plainly owe common law duties of care to take reasonable steps not to cause reasonably foreseeable injury to persons or damage to property, which could include pollution and environmental damage caused by PFAS. Manufacturers will also owe common law duties to take reasonable steps to ensure the products they produce are reasonably safe. To this can be added a strict liability for defective products under the Consumer Protection Act 1987 (“CPA”). Employers will need to consider their obligations under the COSHH regime (Control of Substances Hazardous to Health Regulations): whilst presently no PFAS are subject to a workplace exposure limits (‘WEL’), this may provide false succour because, in an illustration of the overlapping of regulatory regimes, most PFAS that have an MCL (mandatory classification and labelling) as a carcinogen or mutagen will come within the COSHH “ALARP” obligation to keep exposure to as low as reasonably practicable[3].
- Occupiers of land affected by release of PFAS chemicals from factories and plants into the surrounding land or water courses may also have causes of action in public and/or private nuisance. For example, in Re Corby Group Litigation [2009] EWHC 1944 (TCC), the defendant had allowed toxic waste containing heavy metals in the form of mud and dust to escape from land reclaimed from the British Steel Corporation. The claimants, who were born with upper limb deformities, alleged that their mothers’ exposure to the toxic material while pregnant had caused the deformities. Akenhead J allowed the claims on the basis that the defendant’s actions constituted a public nuisance and that it was also liable pursuant to its statutory duty under s.34 of the Environmental Protection Act 1990. This imposes a duty to take “all such measures as are reasonable in the circumstances” to prevent the unauthorised or harmful deposit, treatment or disposal of “controlled waste” and to prevent the escape of the waste from the defendant’s control.
- A key challenge to establishing any of these tortious liabilities is likely to be proving that, based on the standards of knowledge available at the relevant time, the defendant ought reasonably to have foreseen risk to arise from the nature of the proven exposure. This is likely to involve the Court’s scrutiny of historical literature – medical, scientific, trade, and popular – which it is alleged should reasonably have informed manufacturers about the risk of PFAS (or certain PFAS) at various time points. It is noted that, as it stands, only two PFAS chemicals (PFOS and PFOA) have reached a level of scientific research to be considered harmful enough to be placed under regulation.
- A further key battleground is likely to be proof of causation. Significant parallels can be drawn to asbestos; once thought to be an ideal material for use in a number of products, since found to be highly toxic and extremely difficult to remove, resulting in long-tail risks and decades of associated litigation, which is still ongoing.
- Causation has presented a number of difficult challenges in asbestos-related litigation. The courts generally deal with factual causation in tort cases by asking whether the damage would have occurred “but for” the acts or omissions of the defendant on the balance of probabilities. The essential problem in asbestos cases was that since the precise mechanism by which asbestos resulted in cancer is still not fully understood, it was not possible to establish, on a balance of probabilities, that any particular exposure to asbestos has caused a claimant to develop mesothelioma. Further, asbestos was so ubiquitous that it was very challenging successfully to establish that it was a particular source of asbestos which caused the particular disease, or that it came from a particular defendant.
- Similar issues may well arise in PFAS litigation. Whilst the chemicals have been linked to various diseases, thus far there remains limited scientific evidence which has established the specific mode of action for PFAS toxicity. Furthermore, given PFAS appears to be so diffuse that it is now found in the blood of almost every human in developed societies, it can be envisaged that similar causative issues will arise; how will it be established that the PFAS originated from a particular source, or from a particular tortfeasor?
- In asbestos related litigation, the Courts dealt with these issues by significantly, and unusually, modifying the standard principles to be applied. In Fairchild v Glenhaven Funeral Services Ltd [2002] UKHL 22, the House of Lords carved out an unusual exception by ruling that each defendant who had, in breach of duty, been responsible for exposing a mesothelioma victim to a significant quantity of asbestos dust and thus creating a “material increase in risk” of the victim contracting the disease will be held to be jointly and severally liable for causing the disease.
- The decision is remarkable for its frank recognition that the result was adopted for policy reasons. Whilst it might be argued that PFAS has a number of similarities to asbestos, it is very much to be doubted that the modern Courts would be willing to adopt this kind of policy driven exception beyond asbestos-related litigation. Indeed, the Courts have so far been quite vocal about their resistance to any such extension. In International Energy Group Ltd v Zurich Insurance Plc [2015] UKSC 33, Lord Mance labelled it a special extension “which could not be justified by reference to any general principle and depended on a distinction which had no rational factual or legal justification”. In Sanderson v Hull [2008] EWCA Civ 1211, Smith LJ said: “I for my part would accept that great caution is required before any development of the Fairchild exception should be allowed” and found that Fairchild could only be relied on where “there was some other exposure which could have been a potential cause of the injury and … it was scientifically impossible for her to show which exposure caused the injury”.
- The most recent illustration of the courts’ reluctance to extend Fairchild was in May 2024 in Holmes v Poeton [2024] EWCA Civ. 145. The Court of Appeal’s decision in favour of the employer is an illustration of the difficulties of proving a disease was caused by toxic exposure. The Supreme Court then refused the claimant permission to appeal in order to argue for an extension of the Fairchild principle to a claim for Parkinson’s Disease alleged to be associated with exposure to TCE (trichloroethylene, an organocholoride with multiple applications) on the grounds that it was “… not a point of law which ought to be considered at this time”.
- Given PFAS can persist for many decades after its production, limitation is also likely to provide a substantial hurdle to liability. Primary limitation will expire within 3 years for personal injury actions and 6 years for property damage actions from the date upon which the cause of action accrued. Since liability is likely to arise in negligence and/or breach of statutory duty, the cause of action will accrue when it is established that a breach of duty has caused more than minimal damage. This is a fairly low threshold. In respect of personal injury claims, however, the period will be extended until 3 years from the claimant’s date of knowledge (Section 11(4)(b)), or limitation may be disapplied where it appears equitable to do so (Section 33), although this will depend on the disease under consideration, its aetiology and the role of PFAS.
- In relation to claims under the CPA, there is a 10-year “hard” backstop pursuant to s.11A(3) of the Limitation Act 1980. This bars any claim brought more than 10 years after the “supply” of a product. Section 33 of the Limitation Act 1980 does not operate to override this ten-year long stop. Given that the true effects of PFAS are only starting to become known, the utility of the CPA to litigators may therefore be severely restricted.
Insurance Coverage
Trigger for Indemnity
- Since PFAS litigation is likely to involve a long-tail risk, with causative events spanning multiple years and possibly originating decades earlier, an important issue in relation to insurance coverage will be the Court’s construction of the operative ‘trigger’ for indemnity and, consequently, the determination of whether the alleged damage is attributable to the policy period in question.
- Again, parallels can be drawn to insurance coverage disputes relating to asbestos.
- In respect of employers’ liability policies written on a causation basis, since as a matter of expert evidence, it is understood that all exposures to asbestos contribute to asbestos-related disease (unless they can be regarded as de minimis), any tortious exposure to asbestos during the policy year is held to trigger entitlement to indemnity.
- The position in relation to occurrence-based employers’ liability policies insurers was tested in what became known as the ‘trigger litigation’; Durham v BAI (Run Off) Ltd and others [2012] UKSC 14. The crux of the case was whether as a matter of policy construction, damage/injury occurred upon the tortious exposure to asbestos or upon onset of the mesothelioma. The Supreme Court held that, in the particular circumstances, the injury was to be regarded as having occurred (irrespective of whether the word used in the insuring clause was “contracted”, “sustained”, or “suffered”) upon the inhalation of asbestos fibres. That was notwithstanding that the mere exposure to asbestos did not itself constitute any injury or damage, which only occurred upon the development of the first malignant cancer cell. Thus, in EL asbestos cases, all of the policies under consideration were to be construed as if written on a “causation” basis.
- Interestingly, that was not the conclusion reached earlier by the Court of Appeal in relation to public liability policies. In Bolton MBC v Municipal Mutual Insurance Ltd [2006] EWCA Civ 50, the Court of Appeal held that “it cannot be right that, at the stage of initial exposure or initial bodily reaction to such exposure, there could be a liability on the part of Bolton in respect of which they could require to be indemnified under any public liability insurance policy”, such that it found that the injury did not occur upon either exposure or upon initial bodily changes but only at a much later date; either when a malignant tumour was first created or when identifiable symptoms first occurred.
- Therefore, there is a question mark over how these somewhat contradictory rulings may apply to similar insurance policies in relation to PFAS. Will damage/injury be deemed to occur upon the first introduction of PFAS to the human body, or at the point it actually results in disease?
- In relation to damage to property, in Sky UK Limited and Mace Limited v Riverstone [2024] EWCA Civ 1567, the Court of Appeal held that “damage” in the policy meant “any change to the physical nature of tangible property which impaired its value or usefulness to its owner operator”. On this basis, Insureds may argue that the initial discharge of any PFAS into soil or water constitutes “damage” to property, thereby possibly triggering more historic policies. Insurers, conversely, may be able to argue that “damage” only occurs when PFAS concentrations exceed regulatory thresholds or produce measurable impairment to the property.
- It is noted that it was further held that Sky was entitled to recover an indemnity for developing damage and deteriorating damage which occurs after the period of insurance if it flows from indemnified damage sustained during the period of insurance. It is to be queried whether the gradual migration of PFAS through soil or watercourses after an initial pollution event could be considered ‘developing and deteriorating damage’ of this nature.
Exclusions
- It is understood that insurers are increasingly adopting specific PFAS exclusions in general liability policies. These exclusions specify that the insurance does not, for example, cover any bodily injury and property damage related to PFAS exposure, or the design, manufacturing, sale, or disposal of PFAS-related products. Nevertheless, these will not apply to protect insurers against historical long-tail risks.
- Another possible line of defence could be the standard exclusion in liability policies for pollution or contamination unless the release is “sudden and accidental.” In many of the class action cases referenced above, it appears the release of PFAS has been the product of gradual leaching into the soil surrounding manufacturing plants. This may therefore provide an exclusion of liability, albeit coverage will always depend on the particular facts of the matter and the policy wording used. Interesting questions may apply as to whether multiple discrete pollution events – such as periodic discharge of PFAS-laden wastewater – could be considered a series of ‘sudden and accidental releases’.
- In Wolverine World Wide, Inc. v. The American Insurance Co, a Michigan federal court found that a ‘sudden and accidental pollution’ exclusion did not preclude the insurer from being required to provide a defence. Wolverine, a footwear manufacturer, was the subject of hundreds of individual tort actions and three class actions alleging it was responsible for PFAS in the groundwater as a result of its manufacture of footwear from 1958 through 2002. The court ruled the insurers were required to defend Wolverine in these matters “until it is determined that every claim in the lawsuit involving pollution is conclusively determined to be intentionally discharged by Wolverine.”
- On the other hand, in Tonoga, Inc. v. New Hampshire Insurance Co, Tonoga claimed on its insurance policy having settled an action with the New York Department of Environmental Conservation, which accused Tonoga of polluting soil, air, and water supplies in Petersburgh, New York relating to the discharge of PFAS as part of its manufacturing process. The court found allegations in the complaint that PFAS were improperly dumped and spilled over a period of many years suggested the “opposite of suddenness” or “unintended” action.
- A further interesting consideration is whether, for example, the deliberate release of PFAS foam during firefighting could be considered to be ‘accidental’.
- It should be noted that even a much broader pollution exclusion may not entirely bar coverage. For instance, in Colony Insurance Co. v. Buckeye Fire Equipment Co., a US court in North Carolina held the insurer had a duty to defend certain claims against the policyholder arising from PFAS-containing fire equipment. Because some of the claims asserted against the policyholder alleged harm from direct exposure to PFAS products, the court ruled that those claims did not involve “traditional environmental pollution” and were thus outside the scope of an absolute pollution exclusion in the policies at issue.
- In relation to pollution exclusions in insurance policies, issues may also arise as to the proximate cause of the loss. In Brian Leighton (Garages) Ltd v Allianz Insurance Plc [2023] EWCA Civ 8, a fuel pipe located on the claimant’s petrol station was punctured and leaked fuel over the station forecourt and shop. The claimant claimed under the material damage section of its insurance policy, but its insurer, Allianz, declined the claim on the ground that the policy excluded loss caused by ‘pollution or contamination’. The Court of Appeal found that, whilst the petrol damage did involve ‘pollution or contamination’, that was not the proximate cause of the loss, which was the puncture to the pipe, and under established principles an exclusion to cover only applied if the excluded peril in question was a proximate cause of the loss. The same reasoning may apply in PFAS-related coverage disputes, where insurers and policyholders may dispute whether the proximate cause of the claimed loss is PFAS contamination itself or an earlier, non-excluded event in the chain of causation.
Conclusion
- As can be seen from the brief snapshot above, PFAS related litigation is likely to spawn a variety of interesting and novel legal questions. With considerable experience in complex and precedent setting cases across relevant practice areas such as product liability, property damage, construction, personal injury and insurance law, members of Crown Office Chambers are ideally positioned to advise on legal issues which may arise in future PFAS related litigation.
Footnotes:
[1] Serum Concentrations of Per- and Polyfluoroalkyl Substances and Risk of Renal Cell Carcinoma (2020, Shearer et al.); A short review on human exposure to and tissue distribution of per- and polyfluoroalkyl substances (PFASs) (2018, Jian et al).
[2] https://www.scd.uscourts.gov/mdl-2873/index.asp
[3] Analysis of the most appropriate regulatory management options (RMOA). HSE, March 2023.
