Judgment
1ALLSOP P: I have read the reasons of Hodgson JA and Basten JA. Subject to what (largely by way of elaboration) appears below, I agree with them. I agree with the orders proposed by Basten JA.
2The appellant, Mrs Lola Evans (the widow and executrix of the estate of Mr Keith Evans), appeals in point of law against the orders made by the Dust Diseases Tribunal (Curtis J) that there be judgment for the defendant. Various complaints were made as to legal error in his Honour's approach.
3The appellant's first complaint is that the primary judge imposed a but-for test of causation in circumstances where such a case was not put forward by the appellant. That argument should be rejected. At [144] of his reasons, the primary judge set out the arguments put forward by Mr Little SC (who, with Mr Foord, appeared for Mrs Evans below and on appeal):
"Mr Little SC argues that:
(a) In all cases where lung cancer is contracted following exposure to the carcinogens cigarette smoke and asbestos, each agent materially contributes to the development of the disease.
(b) In the alternative, the fibre burden of Mr Evans was probably sufficient to materially contribute to his lung cancer in any event."
These were arguments based on causation by material contribution.
4The primary judge's conclusion at [201] of his reasons was expressed in terms of these arguments:
"I am not persuaded that it is more probable than not that any contribution of asbestos to the cause or progression of Mr Evans' lung cancer was, in the light of his smoking history, material."
5His Honour's reasoning between those points ([145]-[162] as to (a) set out at [3] above, and [163]-[194] as to (b) set out at [3] above) dealt with the matter in this way. The primary judge did not limit himself to a but-for test in the way complained of.
6The appellant's second complaint is that the judge impermissibly used his position as an expert tribunal going outside the evidence in calculating fibre load: cf Dasreef Pty Ltd v Hawchar [2011] HCA 21; 277 ALR 611. This argument should be rejected. The task undertaken by the primary judge at [31]-[62] was not shown to adopt a process or conclusion to have been derived outside the evidence.
7The appellant's third complaint (which is related to the first complaint) was that the primary judge impermissibly used the epidemiological evidence beyond the reason for which it was led by the appellant. The appellant submitted that epidemiological evidence was only led to prove that asbestos was a carcinogenic agent. The primary judge, wrongly, it was submitted, used it to reject a proposition that the relative risk from asbestos (whether alone or in conjunction with smoking) was less than 2 (and so not proved to be more probable than not).
8This third complaint should be rejected. As I said above, the structure of the primary judge's reasons after [149] revealed that he dealt with a case based on material contribution. The first argument put forward ((a) at [3] above) was that for which Dr Leigh contended - that in a manner not fully understood, tobacco and asbestos always worked together synergistically in causing lung cancer. According to this hypothesis, the asbestos can be taken to materially contribute to the cancer as part of one intermingled causative agent. The essence of the proposition was described at [145]-[148] of his Honour's reasons. His Honour said that the proposition that this occurred, in all cases, was "theoretically sound": [145]. His Honour found, however, as follows (at [149]-[150]):
"[149] I am persuaded that asbestos and cigarette smoking may act in combination in contributing to the development of lung cancer.
[150] I am not persuaded that in all cases, and in particular in this case of Mr Evans, that the contribution of asbestos must have occurred, or if it did, that the contribution was material. " (Emphasis in original.)
9These were plainly factual findings. Reasons for these findings were given in the paragraphs that followed. If those reasons contained legal error the factual findings might be vulnerable. Before turning to the reasons and the complaints made of them, something should be said about the question posed in [150] whether the contribution of asbestos "must" have occurred. The question can be seen to reflect some of the language used in Amaca Pty Ltd v Ellis [2010] HCA 5; 240 CLR 111 at 133 [52] and [53], and 134 [60]. It might be, perhaps, that, rather than a question framed in terms of certainty ("must"), it would have been sufficient for it to be concluded that it was probable in any given case that smoking and asbestos worked synergistically together to cause cancer. In any event, that is not how the case was run and his Honour cannot be criticised for positing and answering the proposition put forward by Mrs Evans as the foundation for her relief.
10The first reason for the factual conclusion in [150] is set out in [151]:
"First, because both Professor Breslin and Professor Tattersall, while accepting the theory, dismissed the contribution of asbestos in Mr Evans' case because of its relative insignificance. I accept that a contribution may be material although it is minor but I believe that, in context, the opinions of both medical experts are to the effect that the contribution was not minor but insignificant, that is to say, immaterial."
11This reason was said to be illogical; and illogicality was said to reveal legal error. Assuming without deciding the second of those propositions (cf Amaba Pty Ltd v Booth [2010] NSWCA 344), the illogicality was said to flow from the judge's own findings at [168] and [177] in which he found "significant asbestos exposure":
"[168] My finding of 21.9 fibre/ml/years is approximately six times greater than Mr Roger's estimate of 3.24 fibre/ml/years and Mr Pickford's 'probable' scenario of 3.4 fibre/ml/years. It is nearly double Mr Pickford's 'worst case' scenario. This finding is compatible with the description 'significant asbestos exposure'. It is also consistent with the circumstance that the cumulative dose of asbestos fibre required to double the risk of contracting lung cancer requires a significant exposure for a prolonged period of time.
...
[177] The presence of diffuse pleural thickening does indicate significant asbestos exposure, but I have no evidence that correlates the presence of diffuse pleural thickening with an increased risk of contracting lung cancer. Professor Breslin says he took into account the presence of the pleural thickening."
12The error in this argument is revealed by an examination of the evidence of both Profs Breslin and Tattersall. The "relative insignificance" of the asbestos exposure for the theory of multiplicative or synergistic operation of smoking and asbestos was, for Prof Tattersall, lower than 25 fibre/ml/years (the "absolute bottom end of any risk calculation for lung cancer": Black 138 (T p 133)). Professor Breslin gave similar evidence based on Professor Pooley's measurement: see [110] and [111] of the primary judge's reasons. These views from the two experts, who accepted the theory of the multiplicative or synergistic operation of tobacco and asbestos, provided the factual foundation for the primary judge's conclusion. There was a difference between significant exposure and significant or material contribution.
13Further, the presence of pleural thickening was recognised by the primary judge to indicate significant asbestos exposure ([177]), but there was not evidence acceptable to him that this amounted to an increased risk of cancer: [170]-[177] and [111]. This, likewise, was a factual conclusion.
14The second reason for the factual conclusion in [150] is set out in [152]:
"Secondly, because Dr Leigh concedes that in a particular case the contribution of asbestos may play a very small part, and that he could not say that, more probably than not, Mr Evans would not have contracted his cancer in the absence of the asbestos exposure." (Emphasis in original.)
15As to [152], whilst the primary judge referred to Dr Leigh's evidence (at Black 89 (T p 86)) that he could not say that more probably than not Mr Evans would not have contracted his cancer in the absence of the asbestos exposure, I do not conclude from that that his Honour was not continuing to deal with the question of material contribution.
16The third reason for the factual conclusion in [150] is set out in [153]:
"Thirdly, because epidemiological studies predict that among the class of persons who share Mr Evans' smoking history, the greatest number of those who contract lung cancer after exposure to an equivalent asbestos fibre burden are persons who would have contracted the disease in any event."
17As to [153], again this might be seen as relevant to a "but-for" test and causation otherwise based on material contribution of asbestos through synergistic operation. It deals with the proposition at [150] at a level of analysis beyond that put by the appellant. To that extent, it may not be a relevant reason for the conclusion in [150]. It does not, however, undermine the primary foundation for [150] - the evidence of Profs Breslin and Tattersall that the multiplicative or synergistic theory does not apply to the case of Mr Evans, even though they accepted the theory.
18The fourth reason for the factual conclusion in [150] is set out in [154]-[155]:
"[154] Fourthly, because, even if asbestos and smoking combined causally in the development of lung cancers in all cases, the contribution of asbestos to the development of lung cancer in smokers may take the form of hastening the development of the cancer. That would reconcile the certainty of epidemiological prediction that a certain number of lung cancers will develop in smokers in any event, with the plausible biological theory that the additional risk factor of asbestos exposure will contribute to that inevitable development by way of acceleration.
[155] That acceleration may be minimal or substantial and yet not change the inevitability of the tumour's appearance. If a motor car without brakes travels at a certain speed toward a collision there comes a time when any additional impetus by way of acceleration will not affect the inevitability of disaster."
19As to [154]-[155], this reason was not the subject of debate at trial. With respect to the learned trial judge, I do not understand the relevance of [154]-[155] to the factual conclusion in [150]. Nevertheless, it does not undermine [150] insofar as that paragraph is supported by Professors Breslin and Tattersall.
20The appellant's fourth complaint is based on a fundamental legal question. The appellant submitted that the primary judge failed to apply what should be taken to be the law of causation concerning tortious wrongs in Australia. It was submitted that in circumstances were the defendant created a risk of injury and that injury eventuated and, in circumstances where medical science did not permit a causal conclusion to be drawn on the balance of probabilities, it was sufficient to attribute causal responsibility to a defendant that it materially increased the risk to the plaintiff of suffering that injury. As I understand the submission, the causal connection of material contribution may (not necessarily must) be drawn from that increase in risk alone. Reliance was placed on Fairchild v Glenhaven Funeral Services Ltd [2002] UKHL 22; [2003] 1 AC 32; Barker v Corus UK Ltd [2006] UKHL 20; [2006] 2 AC 572; Sienkiewicz (Administratrix of the Estate of Enid Costello Deceased) v Greif (UK) Ltd [2011] UKSC 10; McGhee v National Coal Board [1973] 1 WLR 1; Resurfice Corp v Hanke 2007 SCC 7 ; [2007] 1 SCR 333; Sydney South West Area Health Service v Stamoulis [2009] NSWCA 153; Adeels Palace Pty Ltd v Moubarak [2009] HCA 48; 239 CLR 420; and Bonnington Castings Ltd v Wardlaw [1956] AC 613.
21The primary judge, concluded at [201] (see [4] above) that any contribution of asbestos to Mr Evans' cancer was not material. His Honour, however, did not approach the matter by reference to the above proposition. If he had done so, the evidence may have permitted a relevant causal conclusion, on that hypothesis.
22The submission should, however, be rejected. Subject to the views of the High Court in respect of any development of the common law or to the operation of any legislation, it can be concluded that at common law, as a general proposition, the increasing of risk of harm by a tortious act is, alone, insufficient for a conclusion of causation by material contribution to that harm or for a conclusion of responsibility in law for that harm.
23It can be accepted that in Resurfice Corp v Hanke at 342-343 [24]-[25], the Supreme Court of Canada expressed the framework for "material contribution" in the absence of a positive conclusion from the "but-for" test as follows:
"However, in special circumstances, the law has recognized exceptions, to the basic 'but for' test, and applied a 'material contribution' test. Broadly speaking, the cases in which the 'material contribution' test is properly applied involve two requirements.
First, it must be impossible for the plaintiff to prove that the defendant's negligence caused the plaintiff's injury using the 'but for' test. The impossibility must be due to factors that are outside of the plaintiff's control; for example, current limits of scientific knowledge. Second, it must be clear that the defendant breached a duty of care owed to the plaintiff, thereby exposing the plaintiff to an unreasonable risk of injury, and the plaintiff must have suffered that form of injury. In other words, the plaintiff's injury must fall within the ambit of the risk created by the defendant's breach. In those exceptional cases where these two requirements are satisfied, liability may be imposed, even though the 'but for' test is not satisfied, because it would offend basic notions of fairness and justice to deny liability by applying a 'but for' approach."
24Further, it can be accepted that the House of Lords and now the United Kingdom Supreme Court has modified the common law in the United Kingdom by accepting that, at least as a special rule in mesothelioma claims, fairness and justice demand that the factual link between the wrongful act and the harm to the plaintiff need only be a wrongful exposure of the plaintiff by the defendant to an amount of asbestos that would materially increase the risk of mesothelioma: Fairchild; Barker v Corus; and Sienkiewicz. In Sienkiewicz, the statements of principle may also be seen not to be limited to mesothelioma.
25Further, it can be accepted that at the foundation of the House of Lords' views in Fairchild and Barker v Corus and of the Supreme Court's views in Sienkiewicz was a re-interpretation of McGhee (contrary to the interpretation given to it by the House of Lords in the 1980s) that supported the appellant's fundamental proposition underlying her fourth complaint. McGhee was not, of course, a mesothelioma case.
26The unanimous decision of the House of Lords in Fairchild can be expressed by reference to the headnote:
"... where an employee had been exposed by different defendants, during different periods of employment, to inhalation of asbestos dust in breach of each defendant's duty to protect him from the risk of contracting mesothelioma and where that risk had eventuated but, in current medical knowledge, the onset of the disease could not be attributed to any particular or cumulative wrongful exposure, a modified approach to proof of causation was justified; that in such a case proof that each defendant's wrongdoing had materially increased the risk of contracting the disease was sufficient to satisfy the causal requirements for his liability; and that, accordingly, applying that approach and in the circumstances of each case, the claimants could prove, on a balance of probabilities, the necessary causal connection to establish the defendants' liability."
27The skill of the author of the headnote was able to avoid reference to the different ways this was expressed by their Lordships. Aspects of these differences emerged in Barker v Corus . Nevertheless, what was common to the several views of their Lordships in Fairchild was the necessity to depart from the common law's usual rule of the need for proof on the balance of probabilities in circumstances where it could be unjust for there to be no recovery. See in particular Fairchild at 66 [32] per Lord Bingham of Cornhill, 69 [40] per Lord Nicholls of Birkenhead, 73 [56] per Lord Hoffmann and 112 [155] per Lord Rodger of Earlsferry. These views reflected the expression of the matter by Justice (now Chief Justice) McLachlin at the commencement of an article written by her Ladyship in 1998, "Negligence Law - Proving the Connection" in N J Mullany and A M Linden (Eds) Torts Tomorrow: A Tribute to John Fleming (LBC Information Services, Sydney 1998). The foundational legal and moral premise that can be seen in Fairchild and in the introductory comments in the above article is that tort law, as an aspect of the rule of law, is concerned with righting wrongful conduct. If self-evident wrongs (so characterised by legitimate human perceptions) are not recognised by the law's rules, and thus go unremedied, people who legitimately feel themselves victims will be left with a sense of injustice. A legitimate sense of injustice should not be the product of the rule of law.
28The avowed change to causal principle by the House of Lords that materially increasing the risk of injury was sufficient factual tortious involvement for causation (or attribution of responsibility) to be established was narrowly confined by all their Lordships in Fairchild : at 40 [2] and 55 [21] per Lord Bingham, 70 [43] per Lord Nicholls, 74 [ 61] per Lord Hoffmann, 91 [108] per Lord Hutton and 118 [170] per Lord Rodger. Crucial to that confinement were factors such as the causal element being singular (only exposure to asbestos) and the inability of medical science to explain cause in terms of a balance of probabilities.
29Further illumination of the policy-based change to the common law in Fairchild can be seen from the lively debate in the judgments in Barker v Corus as to what was, in fact, decided in Fairchild . At issue in Barker v Corus was the extent of several liability of the wrongdoers who had exposed the plaintiff to the asbestos, causing a material increase in risk of contracting mesothelioma. Though all their Lordships (with a caveat by Lord Rodger: Barker v Corus at 610 [100]-[102]) came to the view that the exceptional approach in Fairchild should extend to circumstances where not all the exposure was tortiously caused by the defendants, a restriction was placed on the principle being that there must be one causative agent: Barker v Corus at 587 [24] per Lord Hoffmann (his Lordship recanting his view in Fairchild that this limitation was unprincipled), 599 [64] per Lord Scott of Foscote, 611 [104] per Lord Walker of Gestingthorpe and 615 [121] per Baroness Hale of Richmond. Save for Lord Rodger, all were agreed that the extent of responsibility of individual defendants should be measured by reference to the extent to which they had increased the risk, based on the respective length and intensity of exposure: Barker v Corus at 589-590 [35]-[36] per Lord Hoffmann, 599 [62] per Lord Scott, 612 [109] per Lord Walker and 616 [126] per Baroness Hale. The majority, recognising that it was justice and fairness that had given rise to the exceptional rule, thought that justice and fairness should limit the defendants' respective liabilities by reference to the wrongful exposure. Lord Rodger dissented on this point - all defendants were liable in full, the change in rule in Fairchild being a relaxation of the rules of causation - thus each caused the damage.
30At this point, the Parliament intervened with the Compensation Act 2006 (UK), which reflected Lord Rodger's view in Barker v Corus as to the responsibility of defendants in mesothelioma cases, and not the majority's view of fairness.
31The above discussion of Fairchild and Barker v Corus reveals, at once, the policy questions involved in any conclusion that increasing risk is sufficient for a conclusion of causation or causal responsibility or legal responsibility. Such policy questions are a matter for the High Court, not this Court.
32Fairchild , Barker v Corus and Sienkiewicz all discuss Bonnington Castings and McGhee . Before saying something about these cases, it is to be noted that the common law of Australia has long recognised a legitimate causal connection, in circumstances where a but-for analysis does not give a clear answer, which can be described as "material contribution". The defendant's tortious acts amount to a cause of the plaintiff's injury if the plaintiff establishes that his or her injuries are "caused or materially contributed to" by the defendant's wrongful conduct: March v Stramare (E & MH) Pty Ltd [1991] HCA 12; 171 CLR 506 at 514 per Mason CJ with whom Toohey J and Gaudron J agreed. For this proposition the Chief Justice in March v Stramare cited Duyvelshaff v Cathcart & Ritchie Ltd (1973) 47 ALJR 410 at 417 per Gibbs J; Tubemakers of Australia Ltd v Fernandez (1976) 50 ALJR 720 at 724; Bonnington Castings at 620; and McGhee at 4, 6, 8 and 12. See also the use of the phrase "caused or causally contributed to" in Norton Australia Pty Ltd v Streets Ice Cream Pty Ltd [1968] HCA 61; 120 CLR 635 at 643 per Barwick CJ. Mason CJ's comments in March v Stramare were made in the context of his Honour's discussion of concurrent or successive tortious acts each amounting to a cause and not in the context of materially increasing the risk of the harm that eventuates.
33The passage from the judgment of Gibbs J in Duyvelshaff at 417, cited by Mason CJ was as follows:
"The general principle is clear, that the plaintiff must prove, on the balance of probabilities, that the breach of duty caused or materially contributed to his injury: Bonnington Castings Ltd v Wardlaw [1956] AC 613, at 620; McWilliams v Sir William Arrol & Co Ltd [1962] 1 WLR 295; Wigley v British Vinegars Ltd , supra. This means that 'it is for the plaintiff to prove on a balance of probabilities both that the safety measures would have been effective and that the injured person would have made use of them had they been available': Wigley v British Vinegars Ltd ([1964] AC, at 325) In some cases the fact that the employer is in breach of his statutory duty may itself provide some prima facie evidence of a causal connexion between the breach and the subsequent damage: McWilliams v Sir William Arrol & Co Ltd ([1962] 1 WLR, at 302) or, in other words, 'the breach of duty coupled with an accident of the kind that might thereby be caused is enough to justify an inference, in the absence of any sufficient reason to the contrary, that in fact the accident did occur owing to the act or omission amounting to the breach of statutory duty': Betts v Whittingslowe (1945) 71 CLR 637, at 649. Nevertheless, the burden of proving the causal connexion between the breach and the damage remains on the plaintiff."
34I will return to Betts v Whittingslowe [1945] HCA 31; 71 CLR 637 shortly . The above passage, however, is not authority for the proposition that tortiously increasing the risk of harm suffices for causation of harm. Nor is the reference by Mason CJ to his Honour's own reasons in Tubemakers . In that case, there was a contest about the condition of the plaintiff's hand being attributable to the injury suffered by the plaintiff caused by the defendant's negligence. Mason J (as his Honour then was) said at 724:
"In my opinion, this evidence left it open to the jury to infer that on the probabilities the injury caused or materially contributed to the occurrence of the condition. In drawing such an inference the jury was entitled to have regard, in addition to the matters referred to by Dr Sweeney in his evidence, to other significant circumstances: (a) that before the accident the respondent had suffered no disability in his right hand; (b) that the condition made its appearance shortly after the accident; and (c) that no alternative cause was established or indeed suggested in evidence. The combination of these circumstances, taken together with Dr Sweeney's evidence, provided in my opinion a sufficient basis from which the jury could draw an inference favourable to the respondent.
Reaching this conclusion involves no departure from the ordinary onus of proof which rests upon a plaintiff to establish on the probabilities that a medical condition or disability from which he suffers is "caused or materially contributed to" by the defendant's wrongful conduct ( Bonnington Castings Ltd v Wardlaw [ 1956] AC 613 at 620; at 618, per Lord Reid). Consequently, as the decision in that case demonstrates, the plaintiff will fail if all that he can show is that his disability might have been so caused (see also St George Club Ltd v Hines ( 1961) 35 ALJR 106 at 107; [1962] ALR 39 at 41, where it was pointed out that mere proof of default followed by injury does not show that the default caused the injury)."
Mason J (in Tubemakers ) then referred to passages in the reasons of Taylor J in Australian Iron and Steel Ltd v Connell [1959] HCA 54; 102 CLR 522 at 531-532 and 532-533 and Dixon J in Adelaide Stevedoring Co Ltd v Forst [1940] HCA 45; 64 CLR 538 at 569 as elaborating "with varying degrees of emphasis the general onus which lies upon the plaintiff on an issue of causation where the issue lies outside the realm of common knowledge and experience and falls to be determined by reference to expert medical evidence".
35Australian Iron and Steel was a case in which the respondent's husband collapsed and died whilst walking from home to the train station on his way to work. A claim was made under the workers' compensation legislation. Taylor J considered the relationship between exertion and the injury and said the following at the above-cited pages:
"... the question is not whether exertion may have been a factor in causing death but whether it is probable that it was, and this must fail ( sic ) to be determined by the evidence in the case. No doubt cases have arisen and will continue to arise where the character and sequence of events may strongly suggest that exertion played a material part in bringing about death (cf Adelaide Stevedoring Co Ltd v Forst (1940) 64 CLR 538). But this is not such a case and it is necessary to remember that it is for the applicant to make out a case and that liability is not established merely by proving that exertion may have been a material factor.
...
No doubt we are permitted to know that coronary disease is the cause of many deaths and that sometimes death occurs when the victim is at rest. At other times it occurs whilst he is engaged in some activity which calls for a degree of exertion. In the latter category there will, doubtless, be found cases where exertion was a factor contributing to death whilst in other cases the connexion between the exertion and the death will be no more than temporal. Whether there is a causal, as opposed to a merely temporal, connexion may possibly appear, sometimes, from a significant sequence of events. At other times it may be established by more precise evidence but such a connexion must be shown by a balance of evidence in order to establish liability."
36In Forst , Dixon J had said at the above-cited page:
"... I think that upon a question of fact of a medical or scientific description, a court can only say that the burden of proof has not been discharged where, upon the evidence, it appears that the present state of knowledge does not admit of an affirmative answer and that competent and trustworthy expert opinion regards an affirmative answer as lacking justification, either as a probable inference or as an accepted hypothesis."
37None of these passages supports a proposition of causation by increased risk. Indeed, they are to the contrary, unless the increased risk is part of a body of evidence from which it can be legitimately inferred on the balance of probabilities that the tortious act caused or materially contributed to the injury.
38In Bonnington Castings silica dust that caused the pursuer's pneumoconiosis came from two sources in his employer's factory: "innocent" dust from the pneumatic hammer at which he worked in respect of which no known practical method of extracting or preventing dust was available; and "guilty" dust from swing grinders that were fitted with an extraction device which was negligently not kept free from obstruction. The medical evidence permitted the conclusion that pneumoconiosis was caused by the gradual accumulation of silica dust inhaled (guilty and innocent dust together). The guilty dust being material in its contribution to the disease, causation was proved at 618 per Viscount Simonds, agreeing with Lord Reid, 620-623 per Lord Reid, 623-624 per Lord Tucker and 625-626 per Lord Keith of Avonholm. The "guilty" dust as part of an accumulation was a materially contributing factor or cause. See in particular Lord Reid at 620-621. Mason J in Tubemakers and Mason CJ in March v Stramare specifically referred to Lord Reid's speech in Bonnington Castings at 620, where his Lordship said the following:
"It would seem obvious in principle that a pursuer or plaintiff must prove not only negligence or breach of duty but also that such fault caused or materially contributed to his injury, and there is ample authority for that proposition both in Scotland and in England.
...
... the employee must in all cases prove his case by the ordinary standard of proof in civil actions: he must make it appear at least that on a balance of probabilities the breach of duty caused or materially contributed to his injury."
39None of these passages supports a proposition of proof of causation by increased risk.