The first instance decision in this case was reported in Weekly Update 47/14. The claimant employee was exposed to asbestos over the course of his working life, during which he was employed by the six defendant employers. He died from lung cancer and the issue in this case was whether each defendant was liable and, if so, whether it would be liable in full or in part. The parties agreed that the claimant's cumulative exposure to asbestos had increased his risk of developing lung cancer fivefold. Since the claimant was also a smoker, this risk had further increased by a multiple of five.

Following the decision in Fairchild v Glenhaven Funeral Services Ltd (2002), a defendant to a mesothelioma claim is liable if the negligent exposure "materially increased the risk" of the claimant developing the disease. This is an exception to the normal common law rule that a claimant must show, on the balance of probabilities, that the defendant's tort caused his injury (applying the "but for" test). This exception was developed because for mesothelioma it is impossible to say which exposure to asbestos triggered the disease. It resulted in an employee being able to sue any one of his employers in full.

At first instance, the judge held that lung cancer should be treated in the same way as mesothelioma, as the two were "legally indistinguishable". However, the judge also held that apportionment between the employers was appropriate in this case.

The claimant appealed against that finding, arguing that an "intermediate" category between the conventional approach and Fairchild applied here. He sought to rely on the case of Bonnington Castings Ltd v Wardlaw [1956], which involved a divisible disease (ie one whose severity increases with increased exposure to the agency). There it was held that a defendant will be liable in full if his breach of duty made a "material contribution" to the disease itself (rather than the risk).

This is the first time that the Court of Appeal has considered whether the Fairchild exception applies to a case of multiple exposures leading to lung cancer, rather than mesothelioma. It held that it does and that Fairchild can be applied to cases which are "truly analogous" to mesothelioma (and it was said that there was some support for that view in IEG v Zurich (see Weekly Update 18/15). The Court of Appeal also held that, on the medical evidence, this was not a case like Bonnington Castings. This was not a case where the additional dust exposure caused by the defendant's breach of duty had a "cumulative" effect by adding to the total dust exposure – in other words, it could not be said that each period of exposure materially contributed to the development of the cancer. Accordingly, apportionment was appropriate.

COMMENT: Caselaw has been developing a "Fairchild enclave", ie extending the Fairchild exception to cases outside of mesothelioma. The precise scope of this enclave, and the types of illness or disease which fall within it, are still being worked out by the courts. So, for example, in Novartis v Grimsby, the Court of Appeal opined that it was "highly arguable" that the exception could apply to bladder cancer. The Court of Appeal has now confirmed in this case that the exception could, in certain circumstances, also apply to lung cancer. The courts have sounded a note of caution in the past, though. For example, Lord Brown observed in Sienkiewicz v Greif (UK) Ltd [2011] that: "the unfortunate fact is that the courts are faced with comparable rocks of uncertainty in a wide variety of other situations too, and that to circumvent these rocks on a routine basis would turn our law upside down and dramatically increase the scope for what hitherto have been rejected as purely speculative compensation claims".