Sienkiewicz v Greif (UK) Ltd [2011] UKSC 10

The Supreme Court heard conjoined mesothelioma appeals. It held that the Fairchild exception applies even where a single known occupational exposure is set against environmental exposure, rejecting the “doubles the risk” test. Any non‑de minimis increase in risk suffices, and epidemiological statistics alone cannot displace this special causation rule.

Facts

Sienkiewicz v Greif (UK) Ltd

Mrs Enid Costello died from mesothelioma in January 2006, aged 74. Her daughter, Mrs Karen Sienkiewicz, sued Greif (UK) Ltd as administratrix of the estate. Mrs Costello worked at Greif’s Ellesmere Port factory from 1966 to 1984. Asbestos was used in the manufacturing process; highest levels were on the factory floor, but lower levels permeated other areas where Mrs Costello worked and moved around.

The trial judge found her occupational exposure to asbestos was “very light” and occurred through inhalation of the general factory atmosphere. It was, however, in breach of Greif’s duties. Mrs Costello, like the general population, was also exposed to low-level asbestos in the ambient atmosphere (environmental exposure).

On expert evidence, the judge held that over her working life Mrs Costello’s occupational exposure increased her background environmental risk of mesothelioma from 24 cases per million to 28.39 cases per million – an 18% increase. He therefore concluded that Greif’s exposure had not more than doubled the background risk and, applying a “doubles the risk” test, held that causation was not established and dismissed the claim.

Willmore v Knowsley Metropolitan Borough Council

Mrs Dianne Willmore died of mesothelioma in October 2009, aged 49. Her husband continued her action as administrator. She alleged exposure to asbestos while a pupil at Bowring Comprehensive School run by Knowsley Metropolitan Borough Council.

Nicol J found she had been exposed to amosite asbestos at school in three ways: (1) from works involving removal, handling and disturbance of asbestos ceiling tiles in a corridor used by pupils; (2) from mischievous damage by pupils to ceiling tiles (a finding later overturned); and (3) from intact and broken asbestos tiles stored in a girls’ lavatory used by her. He held that two of these exposures materially increased her risk of mesothelioma and were not de minimis, and awarded agreed damages of £240,000.

The Court of Appeal rejected one of the three routes of exposure but upheld the others and confirmed liability and quantum.

Issues

The Supreme Court considered in particular:

• Whether the special causation rule in Fairchild v Glenhaven Funeral Services Ltd and Barker v Corus UK Ltd (the “Fairchild exception”) applies where there is only one known tortious exposure to asbestos alongside non-tortious environmental exposure (a “single exposure” case).
• Whether section 3 of the Compensation Act 2006 mandates use of a “material increase in risk” test in all mesothelioma cases, or merely presupposes liability established at common law.
• Whether causation in mesothelioma cases can or must be proved by showing that the tortious exposure more than doubled the background risk (the “doubles the risk” test), using epidemiological evidence.
• What constitutes a “material” increase in risk for the purposes of the Fairchild exception and whether the exposures in these cases were de minimis.
• In Willmore, whether the trial judge’s factual findings of asbestos exposure were sustainable.

Judgment

Approach to mesothelioma and causation

The Court reiterated the special features of mesothelioma: it is an indivisible, invariably fatal tumour almost always caused by asbestos; the risk increases with the amount of inhaled fibres; there is a very long latency between exposure and diagnosis; and medical science cannot identify which fibre or exposure caused an individual’s disease, or which defendant’s breach was causative.

Lord Phillips opened by noting:

Mesothelioma is a hideous disease that is inevitably fatal.

Because of this scientific uncertainty, the House of Lords in Fairchild and Barker adopted a special rule: a person who, in breach of duty, exposes a victim to a significant quantity of asbestos dust, thereby creating a material increase in risk of mesothelioma, is treated as having caused the disease and is liable.

Effect of section 3 Compensation Act 2006

The Court held that section 3 does not itself define when a person is liable, nor does it freeze the Fairchild rule in statutory form. Rather, it presupposes liability “by virtue of” exposure which has given rise to liability in tort, whether “by reason of having materially increased a risk or for any other reason”, and then provides that a “responsible person” is liable for the whole damage and jointly and severally with others.

Section 3 therefore does not bar further common law development, nor does it require courts always to apply a material-increase-in-risk test. It simply reverses Barker on quantum by eliminating apportionment in mesothelioma cases.

Rejection of the “doubles the risk” test in mesothelioma

Lord Phillips analysed epidemiology and the “doubles the risk” approach, recognising that if a tortious exposure more than doubles the background risk, statistical reasoning can show that it is more likely than not that the tortious exposure caused the disease. Smith LJ had suggested in the Court of Appeal that, in multiple-potential-cause cases generally, a claimant can prove causation in this way.

The Supreme Court rejected that approach for mesothelioma. Lord Phillips emphasised both the limits and reliability problems of the available epidemiological data and the continuing ignorance about the aetiology of mesothelioma: the abandoned single-fibre theory, possible cumulative and temporal effects of exposures, and uncertainty about how earlier and later exposures interact.

He concluded that, in mesothelioma cases, it is inappropriate to resolve causation solely by statistical analysis of relative exposures and risks; the Fairchild/Barker rule remains justified so long as the scientific “rock of uncertainty” persists. Epidemiology may inform apportionment between multiple tortfeasors (subject to the 2006 Act) and discount clearly non-causative exposures, but it cannot replace the special rule.

Lord Rodger similarly held that, because medical science cannot identify whether the disease was caused by tortious exposure or environmental exposure, the same difficulty arises in single-exposure and multi-exposure cases. The Fairchild exception therefore applies to cases where the only competitor to a tortious source is environmental exposure. He stated that the “doubles the risk” approach cannot sit alongside the Fairchild exception in mesothelioma litigation.

The Court also rejected Smith LJ’s wider obiter proposition that in any multiple-potential-cause case causation can be proved by showing that the tortious exposure at least doubled the non-tortious risk. That guidance was held not to apply to mesothelioma and not to follow from the existing authorities.

Material increase in risk and de minimis exposure

The justices confirmed that “material” in this context simply excludes exposures that are truly trivial or de minimis. There is no quantitative threshold based on doubling of risk. Lord Phillips expressly rejected the suggestion that occupational exposure is material only if it more than doubles environmental exposure; such a standard would collapse the Fairchild rule back into a balance-of-probabilities test.

Given that a very low dose of asbestos can cause mesothelioma and that there is no known safe threshold, the Court held that only exposures insignificant in comparison with other sources could properly be treated as de minimis. On the findings below, Greif’s exposure of Mrs Costello increased her risk by about 18% and was not de minimis. Likewise, the school exposures in Willmore were found to be more than minimal.

Application to the appeals

Sienkiewicz v Greif

The trial judge had wrongly treated this as a case outside Fairchild and applied the “doubles the risk” test, concluding that causation was not proved because Greif’s breach increased Mrs Costello’s risk by only 18%. The Supreme Court held that the Fairchild exception applies in single-exposure cases where the rival source is environmental asbestos; the correct test was whether Greif’s breach materially increased the risk of mesothelioma. On the judge’s own findings it clearly did.

The Court therefore held Greif liable for Mrs Costello’s mesothelioma under the Fairchild rule, with section 3 of the 2006 Act making Greif liable for the whole of the damage.

Willmore v Knowsley MBC

On law, the same Fairchild principles applied. The Council’s argument that the exposure at Bowring Comprehensive was either non-existent or de minimis failed. The Supreme Court, though critical of aspects of the fact-finding and recognising it as “very generous” to the claimant, declined to disturb concurrent findings that Mrs Willmore had suffered non-trivial asbestos exposure in two ways and that this materially increased her risk.

Implications

This judgment confirms that the Fairchild mesothelioma exception extends to cases where a single tortfeasor’s occupational exposure competes only with non-tortious environmental exposure. A claimant need only show that the defendant’s breach made a non‑trivial contribution to the risk of mesothelioma; causation is then established and, by virtue of section 3 of the Compensation Act 2006, that defendant is liable for the whole of the damage.

The Court firmly rejects a general “doubles the risk” test for mesothelioma and cautions against treating epidemiological statistics as conclusive proof of individual causation. Materiality remains a qualitative, case-specific assessment, and de minimis exposure will be rare given the nature of the disease.

More broadly, the decision underscores that mesothelioma occupies a unique position in English tort law. The Fairchild exception is maintained despite its acknowledged harshness to defendants, while the Court signals strong reluctance to create further exceptions to orthodox “but for” causation in other areas.

Verdict: The Supreme Court dismissed the appeals of Greif (UK) Ltd and Knowsley Metropolitan Borough Council, upholding liability in both mesothelioma claims under the Fairchild exception and confirming that each defendant was liable in full for the damage.

Source: Sienkiewicz v Greif (UK) Ltd [2011] UKSC 10