Canada overcame that problem by holding that, in such circumstances, once the plaintiff had established that he had suffered harm, the onus shifted to the defendants to prove that their acts were neither intentional nor negligence. This is a clear modification of the proof of causation rules, which state, ‘it is for the claimant to prove, on the balance of probabilities, that the defendant’s breach of duty caused the damage’.
This modification shows how the conventional rules of causation would produce an injustice to the victim, whose damage would be irrecoverable. To ‘meet the demands of justice’, the proof of causation rule was modified. Despite this, the Cook v Lewis rule should only be applied in cases where the number of potentially guilty defendants is small. In cases with large numbers of potential tortfeasors (i.e. Wintle v Conaust [1981]*4 – five possible tortfeasors), the rule strictly applied might result in, as Prof. Fridman stated; ‘guilt by association,’ an intolerable and unacceptable attitude for the law to adopt.” Therefore, the modification was limited with the demands of justice in mind.
Cook v Lewis showed the courts were willing to adjust conventional rules for the sake of justice. In Bonnington Castings Ltd v Wardlaw [1956] there are also modifications of rules in the pursuit of justice. The plaintiff (W) contracted pneumoconiosis from inhaling silica dust in his workplace. While the main source of dust was from pneumatic hammers (innocent dust) for which the defendants (B) were not in breach of duty, some of the dust (guilty dust) came from saw grinders, which B were in breach as they failed to maintain dust extracting equipment. On this evidence, W could not prove ‘but for’ causation as B’s negligence made it only ‘more probable’ that he would contract the illness. Despite this, the House of Lords determined from an ‘inference of facts’ from the case that the ‘guilty’ dust had ‘materially contributed’ to W’s illness and B was made to pay full damages. This case modified the conventional burden of proof on the claimant. The claimant only had to prove a ‘material contribution’ to the damage, rather than the conventional ‘but for’ requirement.
This modification appears to meet the demands of justice. It is impossible for the claimant to ‘even approximately quantify’ (Nicholson v Atlas [1957]*5) the contributions of ‘guilty’ dust and physically connect it to his damage. This would exempt the defendant’s liability on an unjust technicality. It is quite clear that the defendants have been negligent and the ‘guilty’ dust did contribute to the W’s damage, which leads to the conclusion that ‘justice’ would hold B liable.
The courts decision in McGhee [1972]*6 modified the rules further. The claimant (M) was exposed to brick dust longer than necessary whilst working due to the defendants (C) negligence in not providing a shower to wash after work. The claimant later suffered from dermatitis caused by the brick dust. He could not prove ‘but for’ causation that a shower after work would have prevented him from contracting the disease. However, the House of Lords found that if the claimant could prove that the defendant’s had ‘materially increased the risk’ faced by the claimant this is enough to find the defendant liable for the damage caused, as it is equivalent to a ‘material contribution’. It was also found that the onus of the ‘burden of proof’ should shift to the defendant to disprove the causal link if the claimant can prove the defendant has breached his duty and this has contributed to an increased risk. Due to the current state of medical knowledge, neither side can conclusively prove the causal link. Do these modifications meet the demand of justice? Ultimately, one side has to suffer from the ‘inherent evidential difficulty’ (Lord Wilberforce) and it was determined that ‘justice’ should condemn the ‘creator of the risk’ who ‘must be taken to have foreseen the possibility of damage, who should bear the consequences’. Therefore it seems justifiable that the defendants should be held liable.
This dramatic modification of the rules of causation here would have created a situation where the ‘but for’ test is effectively redundant, as the claimant only has to prove that the defendant’s breach of duty ‘increased the risk’ of injury rather than caused it. Wilsher v Essex AHA [1986]*7 rejected this and clarified that the McGhee decision did not create a new principle of law or reverse the burden of proof. Lord Bridge stated that McGhee judges simply took account of the specific facts of the case and applied ‘a common sense inference of fact that the additional exposure to brick dust had probably materially contributed to the plaintiffs dermatitis’. Bridge’s analysis proves that the judgement in McGhee did meet the demands of justice, not by changing the existing rules of causation, but by applying a common sense judgement to the undisputed facts.
The problem of complex facts in causation is crucially evident in the case of Fairchild v Glenhaven [2002]*8. The claimants suffered from mesothelioma almost certainly caused by the negligent exposure to asbestos fibres at work. The claimants worked for multiple employers who all exposed them to this asbestos risk. Mesothelioma is not a cumulative disease, but caused by a single malignant cell, which could have developed while working for any one of the employers but not all of them. The original verdict in the Court of Appeal held that the claimants appeal failed as they could not prove on a balance of probabilities that the guilty fibres where the result of any particular defendant’s breach of duty.
The question of what would be a just result is difficult. According to the ‘but for’ principle, it would be unjust to punish any one of the employers, if the claimant was unable to prove the causal link between their negligence and the damage caused. Similarly, it would be unjust to not award damages to the claimants, simply because they could not prove which breach of duty had caused the damage (if they were a single tortfeasor as in Wilsher and McGhee, damages would be recoverable). The House of Lords reversed the decision. Despite relaxing the conventional ‘but for’ rule, the demands of justice prevailed as stated by Lord Bingham ‘such injustice as may be involved in imposing liability on a duty-breaking employer in these circumstances is heavily outweighed by the injustice of denying redress to the victim’
In conclusion, the cases discussed reveal the extent to which judges are willing to modify the rules of causation in different situations with varying facts. In cases like Fairchild, established rules may require modification to reach a just result. The courts use their ‘instinctive, common sense’ to decide an issue and use rules of causation as guides. The attribution of legal responsibility to one, other or both of the factual causes is essentially a matter for judicial discretion. Ultimately the rules concerning causation are frequently modified, as seen in the progression from Bonnington to Fairchild (and recently Chesire v Afshar) to meet the demands of justice as perceived by the courts.
Citations: -
*1; 1 QB 428
*2; 1 DLR 1
*3; 33 MLR 386
*4; V.R. 951 (C.A.)
*4B; AC 613
*5; All ER 776
*6; 3 All ER 1008
*7; 3 All ER 801
*8; 3 All ER 305
