Barker v Corus UK Ltd [2006] UKHL 20

Mr Barker contracted mesothelioma after inhaling asbestos dust during three periods of exposure. Two exposures occurred while he worked for employers who had negligently failed to protect him, including Corus's predecessor. A third occurred while he was self-employed and was not attributable to another defendant's breach. Medical science could not determine which exposure had initiated the disease. Mr Barker died before trial, and his widow continued the claim. Corus argued that the Fairchild exception should not apply because not every possible source of exposure involved a breach by a defendant. It also argued that, if liable, it should answer only for the share of risk created by its own wrongdoing.

Did the Fairchild material-increase-in-risk exception apply where some possible exposure was not tortious, and was a responsible defendant liable for all the damage or only its proportionate share of the risk?

The House of Lords held that the Fairchild exception could apply even though one possible source of exposure arose during Mr Barker's self-employment. The relevant wrong was materially increasing the risk that mesothelioma would develop, where scientific uncertainty prevented proof of which exposure caused it. However, the House treated each defendant's liability as several and proportionate to the risk for which that defendant was responsible, taking account of the duration and intensity of exposure and other relevant factors. Corus was therefore not liable at common law for the whole loss. Parliament subsequently changed that remedial result for mesothelioma claims through section 3 of the Compensation Act 2006, under which a responsible person is liable for the whole damage and liability is joint and several.

Within the Fairchild class of cases, wrongful exposure that materially increases the risk of mesothelioma can satisfy the causal requirement despite scientific inability to identify the causative exposure. Barker limited common-law liability to each defendant's contribution to risk, but section 3 of the Compensation Act 2006 displaced that apportionment rule for mesothelioma.

The decision clarified that Fairchild was not confined to cases in which every possible exposure was tortious and identified material increase in risk as the exceptional basis of liability. Its proportionate-liability solution was short-lived for mesothelioma: Parliament enacted section 3 of the Compensation Act 2006 so a claimant may recover the whole loss from any responsible person, leaving contribution between defendants to be resolved separately. Sienkiewicz v Greif (UK) Ltd later confirmed that the exception can operate in a single-defendant case involving environmental exposure.