Written By: Kiana Therrien-Tomas
Reviewed By: Grant Ferguson
Introduction
Where factual causation ends and remoteness begins is not always straightforward in a negligence claim. In Hemmings v. Padmore,[1] the Supreme Court of Canada (“SCC”) clarified the distinct roles of factual causation and remoteness in negligence claims. To establish negligence, a plaintiff must show that the defendant owed and breached a duty of care, causing the plaintiff harm in fact and in law. Causation involves two inquiries: factual causation asks whether the defendant’s breach caused the plaintiff’s injury, while remoteness asks whether the injury was sufficiently connected to that breach to justify liability. These inquiries must remain analytically distinct.[2]
Although Hemmings arose in the medical negligence context, the Court’s discussion of factual causation and remoteness has broader relevance to negligence claims, particularly those involving multiple defendants, different theories about what caused the injury, or conflicting expert evidence.
Factual Background
Sophia Hemmings suffered a cardiac arrest following anesthetic complications during an emergency caesarean section. This resulted in severe and permanent brain damage. She and her family sued several healthcare providers, including her obstetrician, the anesthesiologist at her delivery, and the Scarborough Health Network for the Hospital. The claim against the Hospital included vicarious liability for advice provided over the phone by a nurse before the delivery.[3]
The trial judge found the doctors liable and held the Hospital both directly and vicariously liable. The Court of Appeal set aside the findings against the obstetrician and the Hospital but upheld the anesthesiologist’s liability.[4]
Supreme Court Decision
The SCC dismissed both the Hemmings family’s appeal and the anesthesiologist’s appeal. The result left the anesthesiologist as the only liable defendant.[5] The Court issued three sets of reasons and divided on the application of the governing principles, while providing further guidance on the distinct roles of factual causation and remoteness.
Factual Causation
Factual causation requires the plaintiff to prove, on a balance of probabilities, that but for the defendant’s negligent conduct, the injury would not have occurred. The breach must be a necessary cause of the injury, but it does not have to be the only cause.[6]
The “but for” test requires consideration of the counterfactual: what probably would have happened had the defendant met the standard of care? If the same injury would have occurred, the breach was not a factual cause.[7]
In some cases, a trial judge may infer causation through a robust, common-sense assessment without expressly addressing the counterfactual. An explicit analysis may be required, however, where there are multiple defendants, a significant delay between the breach and injury, competing causation theories, or equivocal or contradictory expert evidence.[8]
Remoteness
Remoteness considers whether the plaintiff’s injury was a reasonably foreseeable consequence of the defendant’s negligent conduct. The injury must have presented a “real risk” greater than a mere possibility. It must be that, a reasonable person in the defendant’s position would not have dismissed the risk as far-fetched. The defendant need not have foreseen the precise sequence of events leading to the injury, just that the risk was genuine at the time.[9]
The Court also emphasized the importance of how the injury is characterized. It should not be framed so broadly that virtually every consequence becomes foreseeable, nor so narrowly that liability depends on predicting the precise sequence of events. Agreeing with the Court of Appeal’s characterization, the SCC treated the relevant injury as a cardiac arrest and resultant brain injury from anesthetic complications, rather than “physical injury” which would have been broader. Once the injury was so characterized, remoteness narrowed to one defendant among many.[10]
Takeaways
Hemmings confirms that factual causation and remoteness are distinct inquiries that should not be conflated. For factual causation, the counterfactual must relate to the specific conduct found to breach the standard of care. In complex cases, each step connecting that breach to the injury should be supported by evidence.
For remoteness, the central question is whether the particular injury fell within the risk created by the defendant’s negligence. The risk must be framed carefully: not so broadly that it captures any possible harm, and not so narrowly that the defendant had to foresee exactly how the injury would occur.
While Hemmings provides further guidance on factual causation and remoteness, their application of these concepts remains highly fact specific. This was demonstrated by the Court’s division over the liability of the obstetrician and the anesthesiologist.
The decision does provide litigants with a clearer roadmap: identify the specific breach, determine what likely would have happened without it, and consider whether the injury that actually occurred was within the scope of the foreseeable risk. Following this roadmap can provide a path both to establishing liability and to successfully defending against it in factually complex, multi-party cases.
[1] 2026 SCC 34 [Hemmings].
[2] Ibid at paras. 42-43.
[3] Ibid at para. 1.
[4] Ibid at para. 2.
[5] Ibid at para. 4.
[6] Ibid at paras. 45-46.
[7] Ibid at paras. 49-51.
[8] Ibid.
[9] Ibid at paras. 70-72.
[10] Ibid at paras. 98-99.
