Published in Insurance/Reinsurance Bulletin April, 2010.

Amaca Pty Ltd v Ellis; the state of South Australia v Ellis; Millennium Inorganic Chemicals Ltd v Ellis [2010] HCA 5

A recent High Court of Australia case considers the causal nexus between exposure to asbestos and lung cancer, where the cancer victim had also been a significant cigarette smoker. The case re-affirms the probable cause test: whether it is more probable than not that the alleged cause in question was effective. Of immediate relevance to bodily injury cases, it could also be applied in other scenarios where loss may be attributable to competing possible causes (or combinations thereof).

Mr Cotton smoked 15-20 cigarettes per day for around 26 years. He was also exposed to asbestos in two workplaces for a total of 15 years. Mr Cotton died of cancer and his estate sued his former employers and a manufacturer of the asbestos cement pipes he had worked with.

The trial judge held that the cumulative effect of smoking and exposure to asbestos operated "in synergy" to cause Mr Cotton's cancer and ordered the employers to pay damages in negligence. The employers appealed, arguing that asbestos exposure had not caused Mr Cotton's injury.

The High Court accepted that it could not be proved conclusively how Mr Cotton contracted cancer. The victim's estate therefore asked the Court instead to infer from the expert evidence that asbestos exposure had caused the cancer.

In finding for the employers, the High Court confirmed that the test is: "whether the plaintiff had established that it was more probable than not that the exposure to asbestos was the cause of the lung cancer". The possibility that exposure may have been "a cause" (short of being "the probable" cause) was not sufficient. The evidence did not show that exposure to asbestos was a probable cause of the cancer. The proposition that smoking and asbestos work together to jointly cause or develop cancer was not established.

The decision reinforces the law in Australia that Plaintiffs must show "probable cause", at least in circumstances where there are multiple potential causes. It is also notable that in considering a victim's exposure to asbestos under different employers, the court commented that the correct approach is to consider separately for each different employer (rather than collectively) whether it was more probable that their negligence was a cause.

The case appears to open the door, in some situations, for a more conservative approach to be taken by the Courts when determining issues of causation. However, in the context of dust diseases, it may be distinguished on the basis that the deceased was a heavy smoker and did not have any accepted markers of asbestos exposure, such as asbestos related disease.

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