Negligence - Asbestos - Burden of proof
Karen Sienkiewicz (administratrix of the estate of Enid Costello, deceased) v Greif (UK) Ltd: Knowsley Metropolitan Borough Council v Willmore: SC (Lords Phillips, Rodger, Brown, Mance, Kerr, Dyson, Lady Hale): 9 March 2011
The first appellant manufacturing company (G) and the second appellant local authority (L) appealed against decisions ( EWCA Civ 1159,  QB 370) and ( EWCA Civ 1211,  ELR 227) concerning the appropriate rule of causation in cases of mesothelioma involving a single defendant.
L and G were the sole known sources of occupational exposure of the respondents (W and S) to asbestos dust. In each case, the extent of the exposure had been found to be small.
The Court of Appeal had applied the principle in Fairchild v Glenhaven Funeral Services Ltd (t/a GH Dovener & Son)  UKHL 22,  1 AC 32 and Barker v Corus UK Ltd  UKHL 20,  2 AC 572 and in each case found L and G to be responsible for exposing W and S to sufficient asbestos dust to create a material increase in risk and therefore jointly and severally liable.
The issues for determination were: (i) whether the rule of causation that had been developed in cases of mesothelioma left any room for applying a test of balance of probability to causation;
(ii) whether the Fairchild exception applied in cases involving a single defendant, and whether it was appropriate to apply a test which attributed causative effect to any factor which more than doubled a risk of a claimant developing mesothelioma;
(iii) what constituted a material increase in risk.
Held: (1) Section 3 of The Compensation Act 2006 had grafted a special rule onto the principle in Fairchild and Barker that applied only to mesothelioma.
That had draconian consequences for an employer who had been responsible for only a small proportion of the overall exposure of a claimant to asbestos dust.
However, it would be wrong to have regard to those consequences because that position had been laid down by parliament.
Section 3 applied where the responsible person was liable in tort for materially increasing the risk of a victim contracting mesothelioma.
Whether and in what circumstances liability in tort attached to one who had materially increased the risk of a victim contracting mesothelioma remained a question of common law which was capable of further development.
The rule in Fairchild and Barker had been adopted to cater for the ignorance that had existed at the time of those decisions about the causes of mesothelioma.
Section 3 therefore did not preclude the courts from reverting to the conventional approach of balance of probabilities should advances in medical science in relation to the disease make such a step appropriate (see paragraphs 58, 70, 142 of judgment).
(2) Knowledge about mesothelioma was based partly on medical science and partly on statistical analysis or epidemiology.
Uncertainty about the biological cause of the disease made it impossible for a claimant to prove causation according to the conventional ‘but for’ test and that was why the special rules of causation in Fairchild and Barker had been devised.
There were special features and knowledge gaps in relation to mesothelioma which meant that it was inappropriate to decide causation on epidemiological data relating incidence to exposure.
The ‘double the risk’ test was therefore not appropriate in cases of single or multiple defendants and the adoption of the special rule of causation set out in Fairchild and Barker was justified in cases where there was one defendant.
Even if it was possible to postulate with confidence that the extent of a defendant’s contribution to a victim’s exposure to asbestos precisely reflected the likelihood that his breach of duty had caused the victim’s disease, there would still be justification for the application of the Fairchild rule where all the exposure was wrongful, Fairchild and Barker followed (paragraphs 11, 19-20, 97-106, 113, 160-162).
(3) Liability for mesothelioma fell on anyone who had materially increased the risk of the victim contracting the disease.
The insertion of the word ‘material’ was intended to exclude an increase of risk that was so insignificant that the court would properly disregard it on the de minimis principle.
There was no justification for adopting the ‘double the risk’ test as the benchmark of what constituted a material increase of risk.
What was de minimis was a question for the judge on the facts of any particular case.
In the case of mesothelioma, a stage had to be reached at which, even allowing for the possibility that exposure to asbestos could have a cumulative effect, a particular exposure was too insignificant to be taken into account, having regard to the overall exposure that had taken place (paragraphs 107-108).
Jeremy Stuart-Smith QC, Charles Feeny (instructed by Hill Dickinson (first appellant) and Berryman Lace Mawer (second appellant)) for the appellants; Christopher Melton QC, Richard Pearce (instructed by Norman Jones) for the first respondent; David Allan QC, Simon Kilvington (instructed by John Pickering & Partners) for the second respondent.