Causation - Material Contribution. Thiruchelvam v. RBC General Insurance Company
In Thiruchelvam v. RBC General Insurance Company (Div Ct, 2022) the Divisional Court considers extensively the 'material contribution' form of causation in a SABS MVA judicial review:
 It is plain that generally the “but for” test is preferred and should be applied. However, the caselaw demonstrates that there are circumstances where it will not provide a satisfactory answer and a consideration of “material contribution” is appropriate.The reasoning continues at paras 55-75.
 In Clements v. Clements a husband and wife were riding together on a motorcycle. It was overloaded. They were unaware that a nail had punctured the rear tire. They were in an area where the speed was limited to 100 km/h. The husband accelerated to “at least 120 km/h” in order to pass a car. The nail fell out, the tire deflated, the husband lost control and the motorcycle crashed. The wife was seriously injured. She sued her husband. The trial judge found that, due to the limitations of the scientific reconstruction evidence, the wife was unable to prove that but for the accident she would not have been injured. Instead, he applied a material contribution test and, on that basis, found the husband negligent. The Court of Appeal set aside the judgment and dismissed the action. “But for” causation had not been proved and the material contribution test did not apply. For the Supreme Court of Canada, the issue was whether the usual “but for” test for causation in a negligence action applied or whether a material contribution test dealt with the issue. The Supreme Court of Canada recognized the two tests were different:
“But for” causation and liability on the basis of material contribution to risk are two different beasts. “But for” causation is a factual inquiry into what likely happened. The material contribution to risk test removes the requirement of “but for” causation and substitutes proof of material contribution to risk. As set out by Smith J.A. in MacDonald v. Goertz, 2009 BCCA 358, 275 B.C.A.C. 68, at para. 17: The Court found that the “but for” test must be applied in a robust common sense fashion. There is no need for scientific evidence of the precise contribution the defendant’s negligence made to the injury. Recourse to a material contribution to risk approach is necessarily rare, and justified only where it is required by fairness and conforms to the principles that ground recovery in tort. This would happen in circumstances where there were two or more tortfeasors and the plaintiff is unable to show that anyone of them was the necessary or “but for” cause of the injury. The special conditions that permit resort to a material contribution approach were not present in the case. This was a simple single-defendant case: the only issue was whether “but for” the defendant’s negligent conduct, the injury would have been sustained.
. . . “material contribution” does not signify a test of causation at all; rather it is a policy-driven rule of law designed to permit plaintiffs to recover in such cases despite their failure to prove causation. In such cases, plaintiffs are permitted to “jump the evidentiary gap”: see “Lords a’leaping evidentiary gaps” (2002), Torts Law Journal 276, and “Cause-in-Fact and the Scope of Liability for Consequences” (2003), 119 L.Q.R. 388, both by Professor Jane Stapleton. That is because to deny liability “would offend basic notions of fairness and justice”: Hanke v. Resurfice Corp., para. 25.
 What is apparent from this decision is that, while the “but for” test is the default test, there are exceptional circumstances where resort may be had to a “material contribution” approach. There are other cases that make that point.
 In Athey v. Leonati the plaintiff had been in two car accidents. He was recovering. He undertook some mild stretching and herniated a disc. He had a pre-existing back condition. The issue was not as between the two accidents, the parties proceeded as if there was only one accident and only one defendant. Rather the question was whether there should be a distribution of fault between the accidents on one hand and the history of back problems on the other, that is to say between tortious and non-tortious causes. The trial judge held that although, due to the pre-existing condition, the two accidents were not the sole cause, they did play “some causative role”. She found them to be a “minor contributing factor” which she quantified as 25% of the cause of the disc herniation. The Court of Appeal dismissed the appeal, not because it necessarily agreed but because the meaning of the phrase “material contribution” as a theory of liability for the disc herniation had not been advanced before the trial judge. The Supreme Court of Canada granted the further appeal. The Appellant was a “thin skulled man”. There was no evidence that the herniation would have occurred without the two accidents. The defendants in the accident claims were bound to take him as he was. The apportionment was set aside and the defendants liable for 100% of the damages the plaintiff had suffered.
 The circumstances in this case are different. The evidence suggests that the each of three accidents contributed to the difficulties confronting Stalin Thiruchelvam. The issue is between three tortious acts not between a tortious act and a non-tortious cause. Even so, I point out that the Court in Athey v. Leonati reviewed the general principles surrounding causation including:
The general, but not conclusive, test for causation is the “but for” test, which requires the plaintiff to show that the injury would not have occurred but for the negligence of the defendant: Horsley v. MacLaren, 1971 CanLII 24 (SCC),  S.C.R. 441. This puts the possibility of exception to reliance on the “but for” test more broadly.
The “but for” test is unworkable in some circumstances, so the courts have recognized that causation is established where the defendant’s negligence “materially contributed” to the occurrence of the injury: Myers v. Peel County Board of Education; 1981 CanLII 27 (SCC),  2 S.C.R. 21, Bonnington Castings, Ltd. v. Wardlaw,  1 All E.R. 615 (H.L.); McGhee v. National Coal Board, supra.
 In Hanke v. Resurfice Corp. the operator of an ice surfacing machine put water where gasoline was supposed to go. Hot water overflowed, releasing vaporized gasoline which ignited, causing an explosion and fire. The operator was badly burned. He sued both the manufacturer and distributor of the machine. He alleged poor design. The gasoline and water tanks were similar in appearance and placed close together making it easy to confuse the two. The trial judge dismissed the action. He found that the plaintiff had not established that the accident was caused by the negligence of the manufacturer or distributor. There was evidence supporting the finding that the plaintiff was not confused by the two tanks. The plaintiff’s own carelessness was responsible for his injuries. The Court of Appeal concluded that the trial judge erred in both his foreseeability and causation analysis. It granted the appeal and ordered a new trial. Among other things, it held that the trial judge had erred by failing to consider the “comparative blameworthiness” of the plaintiff and the defendants and in applying a “but for” test instead of a material contribution test. The Supreme Court of Canada reversed the Court of Appeal and restored the decision of the Trial Judge.
 In doing so the Court was clear that the “but for” test remains the primary tool for the determining causation in negligence cases. The presence of more than one potential cause of an injury did not, as the Court of Appeal had suggested, mean that material contribution test had to be used. The Court observed:
To accept this conclusion is to do away with the "but for" test altogether, given that there is more than one potential cause in virtually all litigated cases of negligence. If the Court of Appeal's reasons in this regard are endorsed, the only conclusion that could be drawn is that the default test for cause-in-fact is now the material contribution test. This is inconsistent with this Court's judgments in Snell v. Farrell, 1990 CanLII 70 (SCC),  2 S.C.R. 311 (S.C.C.), Athey v. Leonati, at para. 14, Walker Estate v. York-Finch General Hospital,  1 S.C.R. 647, 2001 SCC 23 (S.C.C.), at paras. 87-88, and Blackwater v. Plint,  3 S.C.R. 3, 2005 SCC 58 (S.C.C.), at para. 78. Still, the Court recognized there are exceptions:
However, in special circumstances, the law has recognized exceptions to the basic "but for" test, and applied a "material contribution" test. The Court went on to observe that:
Broadly speaking, the cases in which the "material contribution" test is properly applied involve two requirements. And to describe the two requirements:
First, it must be impossible for the plaintiff to prove that the defendant's negligence caused the plaintiff's injury using the "but for" test. The impossibility must be due to factors that are outside of the plaintiff's control… The Court of Appeal sees the greater detail offered in Hanke v. Resurfice as clarifying the exceptions to the “but for” test and the circumstances in which the material contribution test may be applied.
…Second, it must be clear that the defendant breached a duty of care owed to the plaintiff, thereby exposing the plaintiff to an unreasonable risk of injury, and the plaintiff must have suffered that form of injury. In other words, the plaintiff's injury must fall within the ambit of the risk created by the defendant's breach.
 I note that the cases reviewed to this point reflect on the use of these tests in the context of determining whether a party was legally responsible for the injury that was under review: was the defendant negligent? This case is different. Here the test is being used to determine if a particular party is entitled to an elevated level of benefits: did the injury result from the accident, not who caused the accident. Fault for the accident is not an issue. The SABS is a no-fault program. The concern that is the second of the conditions Hanke lists as a requirement before an exception to the “but for” test can be applied (clear that the defendant has breached a duty of care) directs that the constituents of a finding of fault are necessary. This would take the application for benefits outside the fundamental policy that informs the SABS.
 Monk v. ING Insurance Co. of Canada concerned an application for benefits. Over time the applicant was involved in three separate motor vehicle accidents. The first was inconsequential and, it was agreed, of little relevance to the issues in the case. The second was more serious. After the third accident the injuries did not appear to be extensive. As time passed, the applicant’s symptoms intensified. She experienced increasing pain in her neck, discomfort in her arms, limited neck and head mobility, and constant headaches. She underwent spinal decompression surgery in 1999 and again in 2001. Eventually she became an “incomplete quadriplegic”.
 ING Insurance did not dispute that the applicant was catastrophically impaired but blamed the damages on the first and second accidents, when it was not the applicant’s insurer, rather than the third accident, when it was. The trial judge held that causation was established because the third accident materially contributed to the Applicant’s condition and to the deterioration of her symptoms, “despite the role of prior accidents and alleged pre-existing conditions”. At trial counsel for the applicant argued that all that was needed to demonstrate causation was that it be shown, on a balance of probabilities, that the third accident contributed to her injuries. The trial judge agreed and found that the material contribution test for causation was satisfied. On the appeal, Counsel for ING submitted that the trial judge erred in his causation analysis by applying the material contribution test to determine causation.  The Court of Appeal found this problematic in that it represented a complete change of position. At trial ING had urged adoption of a material contribution test. The Court of Appeal continued:
Moreover, the trial judge's application of the material contribution test conforms with a long line of arbitral decisions in which this test has been utilized to resolve causation issues in accident benefits disputes, including in cases where the benefits claimant suffered from a pre-existing condition prior to the accident in question. [See Note 5 below] Before this court, ING offers no authority to support its assertion that the material contribution test does not apply to statutory accident benefits cases. The Court went on to observe that, in the particular case, it didn’t matter because both tests arrived at the same result. It concluded:
Accordingly, where -- as here -- a benefits claimant's impairment is shown on the "but for" or material contribution causation tests to have resulted from an accident in respect of which the claimant is insured, the insurer's liability for accident benefits is engaged in accordance with the provisions of the SABS. In Monk, when examining causation in respect to a claim for benefits the Court exhibited a more flexible approach to the use of the material contribution test. This is not to say that the default reliance on the “but for” test or the requirements for reliance on a material contribution test can be set to the side; only that when it is the application for no fault benefits rather than a determination of negligence (fault) the circumstances are different and that this may be recognized in the application of the two tests.
 There is one further case to which I wish to refer. Sabadash v. State Farm was a judicial review. Like this one, it considered an appeal from an arbitrator to a director’s delegate. The applicant had been injured in a motor vehicle accident. Seven months later his employment was terminated because of his inability to complete the tasks that were expected of him. He applied for benefits pursuant to the SABS. In particular, for the income replacement benefits it provides. Based on medical assessments it had arranged for, the insurer took the position that the applicant did not, as a result of the accident, suffer a substantial inability to complete the tasks his job required. It refused the benefits. The matter went to arbitration. Causation was the central issue. The Arbitrator granted the request. He held:
I cannot accept State Farm’s submission that the “but for” test endorsed by the Courts in accident negligence cases is to be applied to a determination of causation in the statutory accident benefit context.
. West v. Knowles
In West v. Knowles (Ont CA, 2021) the Court of Appeal made these comments on the law of causation and it's terminology:
 The respondent agrees that the “but for” test applies in the case at hand, a concession that is well-taken. As this court recognized in Donleavy v. Ultramar Ltd., 2019 ONCA 687, 60 C.C.L.T. (4th) 99, at para. 69, “the critical threshold … for the application of the material contribution to risk approach is the impossibility of proving which of two or more possible tortious causes is in fact a cause of the injury.” It is the “‘but for’ test [that] is generally applied in establishing causation in the tort of negligence”: Donleavy, at para. 62. This would include cases such as the one before me, which involve the alleged acts of a single tortfeasor.
 In resisting this ground of appeal, the respondent submits that the term “material contribution” can be used as an alternative way of describing the “but for” test. He relies, in part, on the pre-Clements decision in Athey v. Leonati, 1996 CanLII 183 (SCC),  3 S.C.R. 458, at para. 41, where Major J. said, “[t]he plaintiff must prove causation by meeting the ‘but for’ or material contribution test.” The respondent therefore submits that we should treat the references to “material contribution” in this jury charge as communicating the “but for” test.
 Given my view that at the end of the charge the jury would have properly understood the law it was to apply, I need not consider whether it remains appropriate after Clements to use “material contribution” language in describing or applying the causation test. However, I do share the view expressed by van Rensburg J.A. in Donleavy, at para. 72, that using “material contribution” language where the “but for” test applies “is a potential source of confusion”. Given that the phrase “material contribution” is used in the law of torts to describe a test that differs from the “but for” test, it may be prudent to avoid using the terms “material contribution” or “contribution” when describing the “but for” causation test.