AMACA and Ors v Ellis [2010] HCA 5

Paul Cotton smoked 15 to 20 cigarettes per day from the age of 15 to 42. For 2 periods of his working life, he was engaged in employment where he was exposed to respirable asbestos fibre. In 2002, he contracted lung cancer, from which he later died. His widow brought proceedings against the two employers and a supplier of asbestos. This claim was successful at first instance, and the WA Court of Appeal refused an appeal by the defendants. The defendants were given special leave to appeal to the High Court.

In a unanimous decision, the High Court has allowed the appeal and dismissed the claim.

The basis of the Court’s decision is that it was not sufficient for the plaintiff to show for the purpose of causation that exposure to asbestos was a possible cause of lung cancer. He had to prove that it was more probable than not. Where the plaintiff relied on epidemiological evidence to show that cigarette smoking and exposure to asbestos acted multiplicatively in causing cancer, the Court held that the plaintiff failed because the available evidence showed that smoking alone was far more likely to have caused the cancer than it being combined with asbestos. They found that the plaintiff had not shown it to be more probable than not that asbestos was a cause of his cancer, or that exposure to asbestos made a material contribution to his cancer. The latter was not shown because a connection between inhaling asbestos fibre and the development of cancer was not demonstrated.

In dealing with the difficult question of proof of causation in cases where there is no certain scientific evidence as to cause, they said:

The answer to the question can be expressed in several different ways. All depend upon the basic and unpalatable fact that no scientific or medical examination can now say, with certainty, what caused Mr Cotton's cancer or lung cancer in any other particular case. As explained at the outset of these reasons, despite this uncertainty, the courts must, and do, 'reduce to legal certainty [a question] to which no other conclusive answer can be given'33. The courts do that by asking whether it is more probable than not that X was a cause of Y. Saying only that exposure to asbestos may have been a cause of Mr Cotton's cancer is not a sufficient basis for attributing legal responsibility. Observing that a small percentage of cases of cancer were probably caused by exposure to asbestos does not identify whether an individual is one of that group. And given the small size of the percentage, the observation does not, without more, support the drawing of an inference in a particular case. The paradox, if there be one, arises from the limits of knowledge about what causes cancer.

This decision is significant in the area of industrial disease claims, but it also demonstrates a philosophy of the Court that will have broader ramifications for causation in tort law. The Court is due to deliver its decision in Tabet v Gett soon. That case deals directly with the question of loss of chance in medical negligence cases, and if the same philosophy is applied, those types of claims will become more difficult for plaintiffs.

For further information please contact Geoff Bourhil, Partner, l on 9288 6752/ geoff.bourhill@lavanlegal.com.au.