The respondent was badly burned when he mistakenly poured hot water into the gasoline tank of an ice-resurfacing machine, causing an explosion.
He sued the manufacturer and distributor for negligent design.
The trial judge dismissed the action, finding the accident was caused by operator error and that the design was not a reasonably foreseeable cause of the confusion.
The Court of Appeal ordered a new trial, holding the trial judge erred in his foreseeability and causation analyses, specifically by not applying the 'material contribution' test.
The Supreme Court of Canada allowed the appeal and restored the trial judgment, clarifying that the 'but for' test remains the primary test for causation in negligence, and the 'material contribution' test applies only in exceptional circumstances where it is impossible to prove causation using the 'but for' test.
