British Columbia (Workers’ Compensation Appeal Tribunal) v. Fraser Health Authority

(Workers’ compensation – Occupational disease – Causation – Evidence – Standard of proof)

On appeal from a judgment of the British Columbia Court of Appeal (2014 BCCA 499), affirming a decision of Savage J. (2013 BCSC 524).

H, S and M (the “workers”) were among seven technicians at a single hospital laboratory who were diagnosed with breast cancer. Each of them applied for compensation under the Workers Compensation Act on the basis that the cancer was an occupational disease. The Act provides that where a worker is disabled from an occupational disease that is due to the nature of his or her employment, compensation is payable as if the disease were a personal injury arising out of and in the course of that employment. In accordance with the applicable policy, the payment of benefits is conditional upon the employment having been of “causative significance” in the development of the worker’s illness.

The medical experts who provided evidence concluded that there was a lack of a sufficient scientific basis to causally link the incidence of breast cancer to the workers’ employment in the laboratory. A review officer of the Workers’ Compensation Board denied each of the workers’ claims. The workers each appealed the Board’s decision to the Workers’ Compensation Appeal Tribunal. A majority of the Tribunal found that the workers’ breast cancers were indeed occupational diseases. Upon application by the employer to the Tribunal for reconsideration, a reconsideration panel upheld the original decision. The employer’s application for judicial review of the Tribunal’s original and reconsideration decisions was allowed: both decisions were set aside and the matter was remitted back to the Tribunal. On appeal by the workers, the majority of the Court of Appeal dismissed the appeal, holding that the Tribunal’s reconsideration decision was a nullity and that the Tribunal’s original decision was patently unreasonable. The workers now appeal to this Court, raising the issue of whether the Tribunal erred in its approach to causation. The Tribunal also appeals to this Court, raising the issue of whether it can, by way of a reconsideration decision, reopen an earlier decision to consider whether it was patently unreasonable.

Held (6-1): The appeal by the workers should be allowed. The appeal by the Tribunal should be dismissed.

Per McLachlin C.J. and Abella, Moldaver, Karakatsanis, Wagner and Brown JJ.:

The standard of review applicable to the Tribunal’s original decision requires curial deference, absent a finding of fact or law that is patently unreasonable. Because a court must defer where there is evidence capable of supporting a finding of fact, patent unreasonableness is not established where the reviewing court considers the evidence merely to be insufficient.

The presence or absence of opinion evidence from an expert positing or refuting a causal link is not determinative of causation. Causation can be inferred — even in the face of inconclusive or contrary expert evidence — from other evidence, including merely circumstantial evidence. Subject to the applicable standard of review, the task of weighing evidence rests with the trier of fact. In the instant case, the Tribunal’s original decision cannot be said to have been patently unreasonable. While the record on which that decision was based did not include confirmatory expert evidence, the Tribunal nonetheless relied upon other evidence which, viewed reasonably, was capable of supporting its finding of a causal link between the workers’ breast cancers and workplace conditions.

In addition, according to the standard of proof set out in s. 250(4) of the Act, where the evidence is evenly weighed on causation, that issue must be resolved in the workers’ favour. This standard of proof contrasts sharply with the scientific standards employed by the medical experts in the case at bar. The majority of the Tribunal was right to consider that the experts thus imposed a too stringent standard of proof. In relying upon the inconclusive quality of the experts’ findings as determinative of whether a causal link was established between the workers’ breast cancers and their employment, the chambers judge and the majority of the Court of Appeal erred in law.

With respect to the appeal by the Tribunal, the employer agrees with the Court of Appeal’s assessment that the Tribunal’s reconsideration decision was a nullity. Accordingly, there is no reason to interfere with that aspect of the Court of Appeal’s decision.

Per Côté J. (dissenting in part):

There is agreement with the majority with respect to the Tribunal’s appeal only. As for the workers’ appeal, it should be dismissed since the original decision of the Tribunal is patently unreasonable and ought to be set aside. There is no evidence and certainly no positive evidence capable of supporting a causal link between the workers’ employment and the development of their respective diseases.

Experts are responsible for providing decision-makers with precisely those inferences that decision-makers — due to the technical nature of the issues — are unable to formulate themselves. The Tribunal is not presumed to possess medical expertise. As a result, while the Tribunal is not bound by the medical experts’ findings, it cannot simply disregard their uncontradicted conclusions. In this case, the expert reports before the Tribunal were unequivocal: the available evidence could not establish any causal relationship between the workers’ employment as laboratory technicians and the development of their breast cancer.

In the instant case, the medical experts did not seek to establish causation on a level of scientific certainty. Having undertaken a more limited investigation, the medical experts simply found no workplace exposure that could plausibly have increased the risk of developing breast cancer. As a result, even on the relaxed standard of proof applicable under s. 250(4) of the Act, there is still no positive evidence capable of establishing causative significance.

While drawing inferences is important in fact finding, the evidence in the record must still be capable of supporting the inferences drawn. Otherwise, the fact-finder is at risk of straying outside the realm of inference and reasonable deductions and into the wilderness of mere speculation or conjecture. Common sense or inferential reasoning cannot bridge insuperable gaps in the evidence, in either a standard civil action or in an administrative claim under the Act. In the case at bar, the only support for the Tribunal’s original decision is the existence of a cluster of diagnosed cases of breast cancer. The Tribunal’s findings of fact simply do not rise above the level of mere speculation. The Tribunal disregarded the consensus view of the medical experts, in spite of its own lack of expertise in medical matters. The Tribunal also ignored the applicable policy, which states that there must be sufficient positive evidence capable of supporting a finding of causative significance, failing which the only possible option is to deny the claim.

Reasons for judgment by Brown J.

Dissenting reasons by Côté J.

Neutral Citation: 2016 SCC 25