(UPDATE June 29, 2012 – the below decision was overturned by the Supreme Court of Canada in reasons for judgement released today. You can click here to read the Supreme Court of Canada’s reasons)
Last year the BC Court of Appeal provided reasons for judgement in Clements v. Clements in which they tried to clarify the law of causation
In short the BC Court of Appeal provided the following summary of the law of causation in BC negligence lawsuits:
 In summary, having regard to the over-arching policy that the material-contribution test is available only when a denial of liability under the but-for test would offend basic notions of fairness and justice, I agree with the following statement made by Professor Knutsen in setting out his conclusions (at 187):
g) The “but for” test rarely fails, and currently only in situations involving circular causation and dependency causation:
1) Circular causation involves factual situations where it is impossible for the plaintiff to prove which one of two or more possible tortious causes are the cause of the plaintiff’s harm;
2) Dependency causation involves factual situations where it is impossible for the plaintiff to prove if a third party would have taken some action in the face of a defendant’s negligence and such third party’s action would have facilitated harm to the plaintiff;
h) If the “but for” test fails, the plaintiff must meet two pre-conditions to utilize the material contribution test for causation:
1) It must be impossible for the plaintiff to prove causation (either due to circular or dependency causation); and,
2) The plaintiff must be able to prove that the defendant breached the standard of care, exposed the plaintiff to an unreasonable risk of injury, and the plaintiff must have suffered that type of injury.
Today the Supreme Court of Canada granted the Plaintiff leave to appeal (permission to appeal). Clarity in this area of personal injury law will be welcomed by lawyers across Canada and I’ll be sure to report on this case once reasons for judgement are handed down.