Clemets v. Clements (2012) SCC 32

1.      Clements v. Clements (2012) SCC 32 (CanLII)

Clements is the current authority on causation in Canadian personal injury cases. It indicates that the “but for” test is the appropriate test to determine causation.  Clement’s effectively limits the use of “material contribution” test to cases with multiple negligent tortfeasors where the “but for” test is insufficient to determine which tortfeasor caused the damages.

i.                    Background

Clements is a case involving a motorcycle accident whereby the defendant’s motorcycle crashed, seriously injuring his plaintiff passenger. A number of factors contributed to the accident.  Most of the factors stemmed from the defendants negligence. Namely, the defendant was driving a motorcycle in wet weather and approximately 20km/h over the speed limit. The motorcycle was overloaded by approximately 100lbs.  One factor was not related to the defendant’s negligence; a nail punctured rear tire of motorcycle.  When the defendant accelerated the nail fell out, the rear tired deflated and the defendant lost control of the motorcycle.

The defendant’s negligence in speeding and in operating an overloaded motorcycle was not in dispute.  The defendants took the position that it was the nail and not the other factors which caused the accident.

ii.                  Trial level – (2009) BCSC 112 (CanLII). 

At the trial level the judge found that the plaintiff “through no fault of her own is unable to prove that ‘but for’ the defendant’s breaches, she would not have been injured”.  The trial judge found that the plaintiff’s inability to prove causation using the “but for” test was to the limitations of the scientific reconstruction evidence.

The trial judge found that since it was impossible to determine the amount each factor contributed to the injury, the but for test should be replaced with the “material contribution” test.  The defendant was found liable on the basis of the “material contribution” test.  The defendant appealed.


  1. iii.                Court of Appeal – (2010) BCCA 581, 12 B.C.L.R. (5th) 310.

On appeal the court set aside the judgment.  The court found that the “but for” test was the appropriate test and set aside the judgment. The plaintiff appealed the decision to the Supreme Court.


  1. iv.                Supreme Court (2012) SCC 32 (CanLII)

The Supreme Court clarified that the “material contribution” test will only apply in cases of multiple defendants where the plaintiff has proven that “but for” the negligence of one or more of said defendants, the damages would not have occurred.

  1. a.       The current test for causation

McLachlin J. speaking for the majority, described the “but for” test as the ordinarily test for establishing causation.  The Chief Justice reiterated that the plaintiff must show on a balance of probabilities that “but for” the defendant’s negligent act, the injury would not have occurred.

The “but for” test must be applied in a robust common sense fashion with no need for scientific evidence of the precise contribution of the defendant’s negligence to the injury.   At paragraph 15, McLachlin recapped the law of causation as follows:

the basic rule of recovery for negligence is that the plaintiff must establish on a balance of probabilities that the defendant caused the plaintiff’s injury on the “but for” test.  This is a factual determination.  Exceptionally, however, courts have accepted that a plaintiff may be able to recovery on the basis of “material contribution to risk of injury”, without showing factual “but for” causation.

  1. b.      The Material Contribution test

Justice McLachlin held that the correct application of the material contribution test requires the plaintiff to show that the defendant’s conduct materially contributed to the plaintiff’s risk of injury.  In other words, it is not the injury itself that requires examination but the circumstances surrounding the increase in risk of injury.

  1. c.       Review of the Canadian jurisprudence

In determining whether the material contribution test was appropriate in Clements, McLachlin J. reviewed the Supreme Court jurisdiction on the issue of material contribution.  Of relevance is McLachlin J’s interpretation of Athey v. Leonati (1996) 3 S.C.R. 458 [Athey].  At paragraph 22 MacLachlin J. described Athey as follows:

The plaintiff who suffered from pre-existing back problems, suffered a herniated disc after two motor vehicle accidents.  He sued the drivers of the motor vehicles in negligence for his injury.  The trial judge held that although the accidents were “not the sole cause” of the disc herniation, they played “some causative role” (para. 8).  She accordingly found the defendants liable for 25 percent of the plaintiff’s loss.  In the Court of Appeal, the plaintiff sought to uphold the result on the basis of material contribution, but that court declined to consider the issue as it had not been raised at trial.

[The Supreme Court], per Major J., discussed the limitations of the “but for” test and the propriety of exceptionally using a material contribution test.  Major J. emphasized that a robust common sense approach to the “but for” test permits an inference of “but for” causation from evidence that the defendant’s conduct was a significant factor in the injury, and concluded that “[t]he plaintiff must prove causation by meeting the ‘but for’ or material contribution test” (para. 41).  Major J. concluded that the 25 percent contribution found by the trial judge was a “material contribution” sufficient to meet the “but for” test.  The term “material contribution”, read in context, does not detract from the fact that the Court in the end applied a robust, common sense application of the “but for” test, in accordance with Snell.

At paragraph 28, McLachlin J. summarized the Canadian Supreme Court jurisprudence on material contribution as follows:

First, while accepting that it might be appropriate in “special circumstances”, the Court has never in fact applied a material contribution to risk test.  Cook was analyzed on a reverse onus basis.  Snell, Athey, Walker Estate and Resurfice were all resolved on a robust and common sense application of the “but for” test of causation.  Nevertheless, the Court has acknowledged the difficulties of proof that multi-tortefeasor cases may pose – difficulties which in some cases may justify relaxing the requirement of “but for” causation and finding liability on a material contribution to risk approach.


  1. d.      Review of the United Kingdom Jurisprudence


At paragraphs 30-32, the court reviewed the leading UK jurisdiction on causation and the material contribution test.  McLachlin J. paid considerable consideration to the 2012 United Kingdom High Court decisions of Fairchild v. Glenhaven Funeral Services Ltd., (2002) UKHL 22 [Fairhcild], Baker v. Corus UK Ltd., (2006) UKHL 20 [Baker] and  Sienkiewicz v. Greif (UK) Ltd., (2011) UKSC 10 [Sienkiewicz].


In Fairchild and Baker, the plaintiffs developed disease related to toxic workforce agents with multiple negligent tortfeasors exposing the plaintiff’s to asbestos. To determine causation, the courts applied the material contribution test as it was impossible to determine which of the defendants’ negligence exposed the plaintiff’s to the risks.  In that situation, fairness and policy supported a relaxation of the “but for” test.


The Sienkiewicz decision is similar to Fairchild and Baker in that multiple sources of toxic agents which contributed to the plaintiff’s damages.  However, Sienkiewicz pertained to the negligence of a single tortfeasor.  The court in Sienkiewicz relied on the Fairchild and Baker precedents to apply the material contribution test.  At paragraph 42 McLachlin J. differentiated the Sienkiewicz decision from Clements finding as follows:


The United Kingdom Supreme Court took the view that it was bound by precedent to apply a material contribution to risk approach in all mesothelioma cases. Several members of the court in Sienkiewicz noted the difficulty with such a result. Lady Hale observed (at para. 167) that she found it hard to believe that a defendant .whose wrongful exposure might or might not have led to the disease would be liable in full for the consequences even if it was more likely than not that some other cause was to blame (let alone that it was not more likely than not that he was to blame).. In my view, nothing compels a similar result in Canada, and thus far, although Sopinka J.’s remarks in Snell (quoted above at para. 20) do not preclude it, courts in Canada have not applied a material contribution to risk test in a case with a single tortfeasor.

Alexander Rozine is an Associate at D’Angela Fox Vanounou LLP, a plaintiff-side personal injury firm in Toronto.