Fairchild causation

Category: Liability and causation · Reviewed by the Apex broking team · Last reviewed 2026-08-22 · ~6 min read

The problem the rule solves

Ordinary tort causation asks whether, but for the defendant’s breach, the claimant would have suffered the injury. Mesothelioma defeats that test. The disease can be initiated by a single fibre, its latency runs for decades, and where a worker was exposed by several employers, medical evidence cannot identify which exposure caused the cellular change that led to the tumour. Applied strictly, the but-for test would mean that a worker negligently exposed by four employers recovers from none of them, because none can be shown on the balance of probabilities to have caused the disease.

That was the position the House of Lords confronted in Fairchild. Each defendant had breached its duty; each had exposed the claimant to asbestos; the claimant had mesothelioma; and the state of scientific knowledge made proof of which exposure did it impossible.

What Fairchild decided

In Fairchild v Glenhaven Funeral Services Ltd [2002] UKHL 22, decided on 20 June 2002, the House of Lords held that in these circumstances a claimant may establish causation by proving that the defendant’s breach materially increased the risk of contracting the disease, rather than by proving that it caused the disease in the conventional sense. The rule is a departure from orthodoxy, justified by the injustice of leaving a plainly wronged claimant without a remedy because of a limitation in scientific knowledge rather than any weakness in their case.

The exception is narrow. It applies where the same agent (or an agent acting in substantially the same way) is involved, where each defendant was in breach of a duty owed to the claimant, and where the current limits of science make it impossible to attribute the injury to a particular exposure. It is not a general licence to substitute risk for causation across the law of tort.

Barker v Corus and what went wrong with it

In Barker v Corus (UK) plc [2006] UKHL 20 the House of Lords addressed the consequence of the Fairchild rule. If liability rests on the creation of risk, their Lordships reasoned, the damage for which a defendant is liable is the risk it created, so liability should be several and apportioned according to each defendant’s contribution to the total risk rather than joint and several.

The practical effect was to move the risk of an insolvent or untraceable defendant from the defendants to the claimant. A worker exposed by five employers, three of them long dissolved with no traceable insurer, would recover only the proportion attributable to the two that remained. Given how often historic employers and their insurers cannot be found, that outcome was widely regarded as unworkable.

Section 3 of the Compensation Act 2006

Parliament responded within months. Section 3 of the Compensation Act 2006, headed “Mesothelioma: damages”, applies where a person has negligently or in breach of statutory duty exposed a victim to asbestos, the victim has contracted mesothelioma, and because of the nature of the disease it is not possible to determine with certainty whether it was that exposure or another that caused the disease. In those circumstances the responsible person is liable for the whole of the damage caused to the victim by the disease, and is liable jointly and severally with any other responsible person.

The section preserves contribution between responsible persons: one may recover a contribution from another, and in determining the amount the court is to have regard to the relative lengths of the periods of exposure for which each was responsible, unless the parties agree a different basis or the court considers a different basis more appropriate in the circumstances. In short, section 3 restores joint and several liability as between claimant and defendants for mesothelioma, and leaves apportionment to be argued out between the defendants and their insurers.

Why it matters to insurance buyers and insurers

The combination of the Fairchild exception and section 3 means that a single traceable, solvent employer — or its historic employers’ liability insurer — can be required to meet the whole of a mesothelioma award, and must then pursue contribution from others. That is precisely why historic EL policy records have such value, why tracing infrastructure such as ELTO exists, and why acquiring a company can bring with it exposures created long before the acquisition.

It also explains the shape of the market. Employers’ liability is written on an exposure basis; asbestos and disease reserves sit on insurers’ balance sheets for decades; and liability policies commonly carry an asbestos exclusion on new business precisely because the class demonstrated how long a tail can be. For a buyer, the practical consequences are record retention, careful treatment of historic liabilities in corporate transactions, and not assuming that a dormant or dissolved subsidiary has taken its exposures with it.

The boundaries of the exception

Section 3 is expressly a mesothelioma provision. It does not extend the Fairchild approach to other diseases, and the common law exception itself remains tightly confined to cases where the scientific impossibility of attribution is genuine. Cases involving divisible diseases — conditions whose severity increases with dose, such as asbestosis or noise-induced hearing loss — are dealt with by apportionment on ordinary principles, because there the contribution of each exposure can be assessed. Anyone reasoning from a mesothelioma authority to a different disease should check that distinction first.

Frequently asked questions

What is the Fairchild exception in one sentence?

It is the rule that where a claimant develops mesothelioma after negligent asbestos exposure by more than one defendant and science cannot say which exposure caused it, proving that a defendant materially increased the risk is enough to establish causation.

Did Barker v Corus survive?

Not for mesothelioma. Section 3 of the Compensation Act 2006 provides that a responsible person is liable for the whole of the damage and jointly and severally with other responsible persons, which reverses the several, risk-apportioned liability Barker had imposed in mesothelioma cases.

Can one employer be made to pay for everything?

Yes. Because liability is joint and several, a claimant can recover the whole award from one traceable, solvent defendant, which must then seek contribution from other responsible persons. Contribution is assessed having regard to the relative lengths of exposure, unless the parties agree or the court decides another basis is more appropriate.

Does Fairchild apply to diseases other than mesothelioma?

The statutory rule in section 3 of the Compensation Act 2006 applies only to mesothelioma. The common law exception is narrow and depends on the impossibility of attributing the injury to a particular exposure, so it does not transfer readily to divisible diseases where dose and severity can be related to each other.

Related entries

• Employers’ liability insurance
• Employers’ Liability (Compulsory Insurance) Act 1969
• ELTO
• Asbestos exclusion
• Proximate cause

This entry is part of the Apex Insurance Wiki. This entry states the position as at August 2026. It is insurance information, not legal advice. Last reviewed 2026-08-22. Next review: 2027-02-22.

Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority (FRN 724952). This page is general information, not advice on a specific policy.