Kathryn Strong, an amputee on crutches, slipped just after noon on a greasy chip (french fry) on the floor of the sidewalk sales area outside her local Woolworths store, suffering severe spinal injuries from her fall. It was acknowledged that while Woolworths did clean the sidewalk sales area, it had no proper system in place for periodic inspection and cleaning, and the area had not been inspected in the 4.5 hours preceding the accident.
The NSW trial court found that Woolworths had been negligent: it should have seen the chip (which left a grease-mark ‘as a big as a hand’) but failed to do so. The Court of Appeal reversed, holding that it was not open to the judge (who didn’t really address causation in fact) to infer that the chip had been lying on the ground for long enough to have been detected. It was not more likely than not that regular cleaning would have prevented Strong’s injury.
The High Court of Australia reversed again (Heydon J dissenting): Strong v Woolworths Ltd,  HCA 5. The general principle in slipping cases is that if more than one reasonable inspection period has passed, on a balance of probabilities failure to inspect has led to the accident. Strong fell at lunchtime, when chips are likely to be dropped more frequently, but the court noted that in Australia chips are as likely to be eaten for breakfast or as a mid-morning snack as at lunchtime, so it was wrong for the Court of Appeal to conclude that the chip had not been there long enough to have been detected and cleaned up. The CA was also wrong to say that the usual ‘but for’ test for factual causation excludes consideration of factors making a material contribution to the plaintiff’s harm. For the High Court, ‘the determination of the question turns on consideration of the probabilities’ – but whether a material increase in risk would be sufficient to prove causation was left as an open question.
For Heydon J, dissenting, material contribution was irrelevant: either Woolworths ‘made no contribution at all [to the injury], or the only contribution’. He didn’t think there was enough evidence one way or the other to establish when the chip fell or from which to draw inferences about causation.
[Link available here].