The deceased had previously been granted workers' compensation benefits in respect of the lung disease. The question at issue in the present litigation was whether it was a cause of death entitling the deceased's estate to fatality benefits. Both the Board and a review panel concluded that it was not: the cancer caused the death, not the lung disease. On appeal, the Appeals Commission took a different view of causation and allowed the application for benefits. The Board sought judicial review.
The central question here related to causation, a tricky legal doctrine. Do administrative decision-makers have to be correct in defining and applying such doctrines? Must administrative approaches to common law concepts mirror those of the courts? Or can administrative decision-makers carve out different approaches which are appropriate to the discharge of their statutory mandates? Sulyma J. held that she should defer to the Board and Appeals Commission:
The next question was whether the Appeals Commission's conclusion was reasonable. Some space for following an approach to causation which did not mirror the judicial approach was created by s. 24(1) of the Workers' Compensation Act. This subsection provides for compensation to the dependents of workers who die "as the result of an accident". Notably, there is no mention of cause or causation. On its face, the subsection is much more friendly to claimants than the common law, where the rigorous "but for" test reigns supreme (most of the time...). In Nor-Man Regional Health Authority Inc, Fish J, who delivered the judgment of the Supreme Court of Canada, commented at para 44 that while common law and equitable doctrines emanate from the courts, that does not mean that arbitrators lack the legal authority or the expertise to adapt and apply those doctrines in a manner which is more appropriate to the arbitration of disputes and grievances in a labour relations context. In my view, the same can be said of the WCB and Appeals Commission. They too have the necessary legal authority and expertise to adapt common law principles such as causation in a way which complies with the purpose of the WCA and conforms to WCB policy.
Sulyma J. recalled the observations of Donald J.A. in Kovach v. Singh, 1998 CanLII 6423:
The Board was not bound to apply common law principles of causation, such as novus actus interveniens, in deciding the matter. No single theory of causation can be said to be infallible or universally applicable. What works for a tort based system may be unsuitable for a no fault scheme. It all depends on the policy goals of the system. The Board may decide that in order to encourage workers to undergo treatment for their industrial injuries, it must cover mistakes made during treatment. It may decide that it is unfair to deny coverage in such circumstances or inconsistent with a broadly inclusive policy of worker protection.
Lucky for it that it was against this backdrop that the Appeals Commission had misunderstood the common law of causation:
I think it would have been preferable for the Appeals Commission to avoid attempting to follow the letter of the law of causation. Both the observations of Donald J.A. and the provisions of its constitutive statute gave it the scope to do so. Indeed, getting the law wrong exposes an administrative decision-maker to the risk of their decision being held unreasonable on judicial review. Far better to articulate an outcome in terms of the purposes of the statutory scheme, turning to the principles of the common law only for general assistance and inspiration, and not slavishly following them as though they were etched on tablets of stone (with apologies to David Cheifetz). The Appeals Commission purported to resort to the “material contribution” test in tort law. It interpreted the test as being whether the compensable conditions were a material contribution to Mr. Kanuga’s death. In fact, the tort test is whether the defendant’s breach of the duty of care materially contributed to the risk of injury. Use of that test in negligence law is restricted to those rare circumstances where factual “but for” causation cannot be shown because one or more of a number of negligent acts by multiple actors in fact caused the injury, but it is impossible for the plaintiff to establish on a balance of probabilities which negligent actor or actors caused the injury (Clements at para 13). That was not the situation here....
 The role of the WCB and the Appeals Commission was to determine if Mr. Kanuga’s death was the result of his compensable conditions. Did his compensable conditions cause his death? In making that determination, it was reasonable for the Appeals Commission to take the view that death is the result of a compensable condition if that condition is connected or related to and materially contributes to the death. While there was evidence on both sides of the question, it is clear from the decision of the Appeals Commission that it was satisfied that Mr. Kanuga died as a result of his compensable injuries in that they played a material role in, were involved in, and materially contributed to his death. They were a cause of his death. As a result, the decision of the Appeals Commission that Mr. Kanuga’s dependents were entitled to fatality benefits under the WCA fell within a range of possible, acceptable outcomes which are defensible in respect of the facts and law.
UPDATE: A twitter interaction with Benjamin Oliphant suggested a further thought. Relaxations of the but-for standard are policy-driven. As Smith J.A. put it in Chambers v. Goertz, 2009 BCCA 358, a passage approved by the Supreme Court of Canada:
 “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”: Resurfice Corp. v. Hanke, para. 25.Where the legislature can plausibly be taken to have given administrative bodies latitude to depart from the rigours of the but-for test, it seems wholly appropriate for them to do so. Indeed, if such statutory warrant has been given, it is arguably more legitimate for them to achieve policy-driven conclusions than for common law judges to try to bend the arc of causation towards their preferred outcomes.
UPDATE 2: See also Alberta (Workers’ Compensation Board) v Alberta (Appeals Commission for Alberta Workers’ Compensation), 2013 ABCA 412:
 The question then is whether the causation test applied by the Commission is consistent with a reasonable interpretation of the statutory framework. In other words, was it reasonably open to the Commission to conclude, in the context of its statutory framework, that Mr. Kanuga’s death was compensable because the asbestosis was a material, in the sense of being a significant, condition contributing to his death?
 The Commission did more than simply apply its interpretation of the common law material contribution test. It considered the relevant provisions of the Workers’ Compensation Act and Board policies in the context of the Act as a whole in order to determine whether that statutory framework was consistent with compensation in circumstances where the compensable injury was not the sole cause of death but was a material, in the sense of being a significant, contributing cause. It concluded that “a broader reading of the phrase ‘the cause of death’ would be more consistent with the philosophy of the workers’ compensation scheme than a more rigid reading which considered ‘the cause of death’ to mean sole or only cause of death”: para 26.
 The Commission’s interpretation of the statutory framework is one that was reasonably open to it in the circumstances of this case. For example, ss. 24(1) and 70(1) of the Workers’ Compensation Act provide for compensation where a worker “dies as a result of an accident” and Policy 03-01, Part I refers to factors which contribute to the injury. The Commission’s decision is consistent with a reasonable interpretation of the statutory framework and the principle that the Workers’ Compensation Act should be given a broad liberal interpretation so as to provide as many injured workers with as much compensation as the statutory framework will reasonably permit: Shuchuk at para 46. It was reasonable for the Commission to conclude that the statutory framework did not compel the application of the common law but for test in the circumstances of this case.