ICI AUSTRALIA OPERATIONS PTY LTD v WALSH and ORS SUPREME COURT OF NEW SOUTH WALES COURT OF APPEAL MASON P, MEAGHER and HANDLEY JJA 8 August 1997, 3 October 1997 [1997] NSWCA 157 NEGLIGENCE — CAUSATION — MULTIPLE — DEFENDANTS — LATENCY PERIOD OF MESOTHELIOMA — EXPERT EVIDENCE — WHETHER EXPOSURE TO ASBESTOS DUST CAUSALLY RELEVANT AS A MATTER OF PROBABILITY The appellant was one of five defendants found liable in negligence by Curtis J for the mesothelioma contracted by the first respondent, Mr Walsh (now deceased). The defendants employed the first respondent between 1964 and 1996, the appellant between 1986 and 1996. The trial judge found that all asbestos exposure was causative. The findings of liability against the other defendants were not challenged. In finding that exposure during Mr Walsh's employment with the appellant was a "cause" of the disease, the trial judge accepted expert evidence that a latency period for this disease could be under 10 years. HELD: Appeal allowed (per Mason P and Handley JA; Meagher JA dissenting): (1) The trial judge's findings that all asbestos exposure was causative and that the risk of developing mesothelioma was materially increased by further exposure during Mr Walsh's employment with the appellant was not open on the evidence given that neither expert accepted the theory that mesothelioma was the result of a person's total exposure to asbestos. Bonnington Castings Ltd v Wardlaw [1956] AC 613; McGhee v National Coal Board [1973] 1 WLR 1; Wilsher v Essex Area Health Authority [1988] AC 1074 referred to. (2) The expert evidence did not support a finding that the mesothelioma contracted by Mr Walsh was caused or materially contributed to by his asbestos exposure while employed by the appellant. Mason P I have had the advantage of reading the judgment of Meagher JA. Unfortunately I disagree with it. The sole issue in this appeal relates to the causal link between the appellant's conduct (the negligent exposure of its employee to a foreseeable risk of injury) and the fatal mesothelioma suffered by Mr Walsh. It is important to recognise that this is an appeal by way of rehearing from a decision of a judge sitting without a jury. The Court of Appeal's jurisdiction to correct error is not confined to absence of evidence or other error of law.! FINDINGS BELOW Curtis CCJ found that Mr Walsh worked for a series of employers between 1964 and 1996. Between 1964 and 1984 he was exposed to, and inhaled, visible asbestos particles during approximately 20% of his working hours at a Matraville refinery. The first, second and third defendants were his employers for varying lengths of time in sequence during this period. In 1985 Mr Walsh was employed for nine months by the fourth defendant at its Botany chemical factory. Exposure was "very minimal" when compared with the earlier exposure between 1964 and 1. See generally Warren v Coombes (1979) 142 CLR 531 and Moran v McMahon (1985) 3 NSWLR. 2 UNREPORTED JUDGMENTS 1984, but nonetheless the work generated visible asbestos dust. These facts led to findings of liability against each of the first four defendants which are not challenged on appeal. Mr Walsh's employment with the fifth defendant (the appellant) was between 1986 and 1996. However, it was during the first 18 months of that employment that exposure to visible concentrations of asbestos dust occurred, and this was for an aggregate of approximately three weeks. There was some later exposure to lesser concentrations of asbestos. The learned judge found that exposure during Mr Walsh's employment by each of the fourth defendant (Hatrick) and the appellant was "a cause" of the disease. He rejected the submission that the uncommonly short latency period involving those parties should lead to a finding that the exposure was not causally relevant as a matter of probability. In doing so he accepted, as he was entitled to do, expert evidence that a latency period of under 10 years is possible for this disease. The judge held that the appearance of mesothelioma is uncommon under 20 years and very uncommon under 10 years. Nevertheless he found liability against the fourth defendant and the appellant for the following reasons: "... accepting the opinion of Dr Schneeweiss and Dr Joseph I find that all asbestos exposure is causative of the disease mesothelioma Dr Schneeweiss, in answer to a question as to whether the exposure in the employ of the 4th and Sth defendants materially contributed to the development of the plaintiff's mesothelioma, said this 'Well, the answer is, I don't know, but I continue to feel that I need to assume in the absence of an ability to isolate a particular event or period of time from others, that all exposures may well have played a significant contributory role in the subsequent development of his malignancy'. If any exposure materially contributed to the risk of contracting the disease, that exposure is as causally relevant as any other exposure which in fact materially contributed to the disease. It is not necessary that the plaintiff apportion the extent of contribution because the law gives him, as a matter of policy, a complete remedy against each defendant. Before entering the employ of the 4th and the 5th defendant, the plaintiff was at risk of developing mesothelioma because of his earlier exposures. That risk upon the evidence was materially increased by the further asbestos exposure in the employ of Hatricks and ICI. It may be that the mesothelioma was caused by the earlier exposure in the sense that its genesis was to be there found but it may not have emerged were it not for the later fibre burden. If this burden was demonstrated to be materially contributive, the 4th and the 5th defendants could not escape liability. They argue that because the plaintiff, upon the evidence, cannot explain this organic contribution in fact, he must fall because increased risk is no longer relevant once sufficient cause is found elsewhere. The seed has been sown. The short answer to this argument is that without the later exposure, the seed may not (despite the probabilities) have flourished, either as soon, or at all. As Dr Schneeweiss said... the whole concept of the delayed development of mesothelioma, is something which the interaction of the seed and soil between the asbestos fibre and the soil of the lung in this instance, is something which clearly does not fall into precise categories that we can explain away on one theory alone. ' The latency statistics do not assist in gauging the effect of aggravating exposure cumulative upon the initial causative exposure. It is unnecessary that I determine the cause of the plaintiff's mesothelioma The submissions of the 4th and 5th defendants, in the words of Lord Salmon in McGhee v National Coal URJ ICl AUSTRALIA OPERATIONS PTY LTD v WALSH and ORS (Mason P) 3 Board, '... confuse the balance of probability test with the nature of causation '. I find that the exposure in the employ of the 4th and 5th defendants is a cause of the plaintiffs disease of mesothelioma." I will return to this passage, and the expert evidence to which particular reference is made, at a later portion of this judgment. The second defendant (Hatrick) was held entitled to indemnity from the third defendant in respect of its liability for exposure during 1975 and 1976. Liability was then apportioned amongst the remaining defendants found liable in the following proportions: First defendant (Boral) (1964-69) 25% Third defendant (Ampol) (1969-1984) 65% Fourth defendant (Hatrick) (1985) 5% Fifth defendant/appellant (ICI) (1986-1996) 5% ISSUES IN THE APPEAL On 19 December 1996 a verdict and judgment was entered for Mr Walsh against each of the five defendants in the sum of $390,947. As indicated, responsibility was apportioned in various percentages as between the first (Boral,, 25%) third (Ampol, 65%) fourth (Hatrick 5%) and fifth (ICI, 5%) defendants. No order has been made for the costs of the proceedings below, apparently in oversight. On 27 July 1997, shortly before the appeal was argued, Mr Walsh died. It was proved that he was survived by his widow, Noeline Mary Walsh, who is the executor of a will dated 18 April 1996, presumably the deceased's last will. Mrs Walsh should be appointed as first respondent pursuant to Pt8 rl0. Hereafter a reference to the "first respondent" is intended as a reference to the deceased or the person appointed to represent his interest in the litigation, as applicable. The appellant seeks an order that the verdict against it be set aside, and that there should be a verdict in its favour against the first respondent. The first respondent defended the judgment in the court below, and was supported in this endeavour by the second (Boral) and fourth (Ampol) respondents. The third respondent (Coltec) submitted to the orders of the Court, save as to costs. The fifth respondent (Hatrick) did not appear. The four parties that took an active role in the appeal accepted that it would be necessary to reallocate the apportionment of the burden of the verdict in favour of Mr Walsh in the event that the appellant were successful. Ultimately those four parties submitted a memorandum inviting the Court of Appeal to make orders as to the apportionment of the 5% required to be contributed by the appellant towards Mr Walsh's verdict, in the event that the appeal succeeded. The issue of costs of the trial and in the Court of Appeal was also addressed in written submissions put to the Court, by leave, after judgment was reserved. CAUSATION AND MESOTHELIOMA CLAIMS My views in relation to causation and negligence claims relating to mesothelioma are set out in Bendix Mintex Pty Ltd & Ors v Barnes.? They need not be repeated at length. I recognised that a plaintiff need establish no more than that his or her injuries are caused or materially contributed to by the defendant's 2. Court of Appeal, unreported, 29 July 1997. 4 UNREPORTED JUDGMENTS wrongful conduct. I referred to a number of procedural or adjectival concessions made by the law in favour of the uncertain plaintiff. Nevertheless it was my view that neither these, nor any authoritative decision of the High Court, supported: "\.. the principle that a party who negligently exposes a plaintiff to a risk of injury will be liable unless the plaintiff can [also] persuade the trier of fact that it was probable that the risk came home." Quoting from an academic article,3 I held that: "The law does not equate the situation where the defendant had materially increased the risk of injury with one where he had materially contributed to the injury." Applying these principles to cases involving mesothelioma and multiple defendants I concluded that the ultimate issue becomes one of deciding which (if any) of the persons sued were shown, on the balance of probabilities, to have caused or materially contributed to the plaintiff's mesothelioma. Expert evidence may establish that a defendant's conduct might have caused or materially contributed to the illness, even though there may be a weight of evidence to the contrary. Nevertheless there remains a critical distinction between expert evidence that a causal link is possible, and a sustainable finding by the trier of fact that it was demonstrated as a matter of probability. As one might expect, the principles are pithily stated by Glass JA:4 "The issue of causation involves a question of fact upon which opinion evidence, provided it is expert, is receivable. But a finding of causal connection may be open without any medical evidence at all to support it..., or when the expert evidence does not rise above the opinion that a causal connection is possible.... The evidence will be sufficient if, but only if, the materials offered justify an inference of probable connection. This is the only principle of law. Whether its requirements are met depends upon the evaluation of the evidence." I note the second respondent's written submission to the effect that the Court should not follow Bendix. APPLICATION TO THIS CASE At the end of his judgment Meagher JA states that "Different independent simultaneous causes are very different from a continuous cumulative set of circumstances." l agree. But where I respectfully disagree with his Honour is in the conclusion that there was evidence that established an evidentiary or persuasive basis for the tribunal of fact to hold that mesothelioma is the result of a "continuous cumulative set of circumstances" in the sense discussed in cases such as Bonnington Castings Ltd v Wardlaw and McGhee v National Coal Board® as interpreted by the majority of the House of Lords in Wilsher v Essex Area Health Authority.7 Properly understood, the requisite expert evidence is lacking in the present case which would ground a conclusion of causation in fact. Alternatively, even if there were evidence of this as a possibility, it was clearly outweighed by » Andrew Grubb in [1988] Cam LJ 350. 4. In Fernandez v Tubemakers of Australia Ltd [1975] 2 NSWLR 190 at 197, citations omitted. An appeal to the high Court was dismissed: see Tubemakers of Australia v Fernandez (19760 50 ALJR 720. [1956] AC 613. [1973] 1 WLR 1. . [1988] AC 1074. one URJ ICl AUSTRALIA OPERATIONS PTY LTD v WALSH and ORS (Mason P) 5 other unchallenged evidence which negated the probability in fact that the deceased's exposure during the time of his employment with the appellant was a cause of his mesothelioma. The trial judge accepted the evidence of Dr Schneeweiss and Dr Joseph.' Iam content to proceed on the basis that his preference for the evidence of these witnesses over that of Dr Gandevia who had been called at the trial for the fourth defendant (Hatrick) was beyond appellate challenge: see Ahmedi v Ahmedi.? However, properly understood, the evidence of those doctors does not justify an inference of probable causal connection. The passages from Dr Schneeweiss' evidence relied upon by the trial judge, the respondents and by Meagher JA must be read in the context of the evidence from that witness as a whole. Likewise with Dr Joseph. Only then can it be seen what each doctor was intending to convey as he attempted to communicate scientific concepts to a tribunal concerned with legal and normative issues such as fault and causation. I shall therefore set out in numbered paragraphs several extracts from evidence of Dr Schneeweiss and Dr Joseph. The emphases are mine. Dr Schneeweiss 1. In his written report dated 18 June 1995 Dr Schneeweiss said that: "T accept that the history provided by Mr Walsh in relation to the extent of asbestos exposure previously experienced by him as being the aetiological causation of his malignant mesothelioma and, having regard to the time intervals involved, would postulate on the balance of probabilities that his condition is causally related to some or ail of his employment history between 1964 and 1996." [This evidence is explained' particularly in passages 4 and 5 below.] 2. Q. Is the general medical view about mesotheliomas that all exposures to asbestos are relevant in the final analysis to the production of the malignancy known as mesothelioma... A:... all exposure to asbestos is taking [sic] into account in development. Q. You cannot exclude any single exposure, doctor, they are all relevant to the development of the condition known as mesothelioma A. That is correct. Q. Doctor, is the actual mechanism whereby the mesothelioma results from those various exposures, is that scientifically well understood. A. There are a lot of theories, even these days, with a good deal of new work being done but it is not clearly understood. Q. Is this the position that medical science has never been able to clearly exclude from the actual development or pathological change that occurs in the cell which initiates the malignancy, never been able to isolate any particular exposure out of any particular patient's cumulative experience of exposure to asbestos. A. If I've understood your question, I don't see how you can do that restrospectively in individual cases who have then died." (AB 237-8) 3. [Anything less than 15 years lead fume] "would be distinctly unusual and rare". (AB 240). 4. °Q. The way you expressed it in your report, in relation to Mr Walsh, is that some or all of his exposures may have caused the mesothelioma 8. The latter's evidence was tendered pursuant to s25(3) of the Dust Diseases Tribunal Act 1989. 9. (1991) 23 NSWLR 288. UNREPORTED JUDGMENTS A. I naturally in an individual patient, where there is a cumulative exposure and experience to asbestos exposure, that in the absence of my being able to define it in any other way, I have to consider this is an aggregate which is relevant." (AB 241-2) 5. "'Q. 1985 to 1986, now would you regard that as an exposure which materially contributed to his condition that he suffers from now. A. Td have to say that I don't know but that the answer is... that, on the basis of what has been conveyed in our understanding of this here, the more recent exposures, in view of the lead time, are I suppose on the basis of possibility and probability, less likely to have had a more major impact. On the other hand, I repeat again, I think is simply unclear as to when the mesothelioma process develops. The fact that there is a long lead time from exposure to the development does not mean that if your exposure had ceased at a certain time, that therefore the development could not have continued, neither does it mean that y you were exposed to a possible factor, making for -mesothelioma, 20-30 years ago, that having no further exposure somehow gives you some kind of relative immunity. Q. You raised, dealing with it on the balance of probabilities and the balance of possibilities. You would agree with me, would you not, that in relation to the history I have given you, of his employment at Hatrick, it is merely possible that his exposure to asbestos there was a contributing factor. A. Possibly as distinct from probable? Q. Yes. A. Well, I would simply say that any exposure to asbestos, I would assume plays or may play a part in subsequent developments that are asbestos related but I am not in a position, really to argue whether or not 1985 in this instance, was a window of no opportunity, as compared with earlier periods. I simply - that is precisely the reason why the wording was used in the way that it was, maybe it isn't clear, but it's - I'm unable to separate and distinguish between one period and another in relation to an accumulation of exposure." (AB 243-4) 6. [Referring to the total fibre burden theory] "T find it astonishing that this concept is applied in this situation, and I think the evidence will need to become a good deal harder than some of the suppositions that have been made, but it doesn't seem totally impossible..." (AB 244) 7. °Q. You do not really try and determine which exposure it was that caused mesothelioma A. No. Q. You just look at the whole history. A. Well, let me put it this way, when I'm confronted with a patient, the question of cm industrial relationship with the development is only - is something which only arises post hoc, after the diagnosis has been established. Mr Walsh could well have had a malignant effusion due to some other tumour, he could well have had an effusion related to pneumonia, so the question of entering into the possibility of this, and that is precisely why, when you - when I was questioned about what he told me about his job at the time, the time that I saw the man, the time that I made these notes, there was no question of asbestos related diagnosis at that time. The man presented to me with a large URJ ICl AUSTRALIA OPERATIONS PTY LTD v WALSH and ORS (Mason P) 7 pleural effusion which needed diagnostic clarification. He was therefore admired to hospital." (AB 245) 8. "Q. Would you agree that the other main thing, apart from the exposures themselves, to asbestos, is the time when those exposures to asbestos occurred. A. Yes, but in the context of an individual patient, that 's irrelevant, that's where the anecdotal cases - reports come in, in seeing a patient, I am concerned with the history background that may be related to asbestos exposure. It matters little - it matters not at all in his medical management or in the diagnosis as to whether that exposure was five, 15, 25, 50 years ago, for how long it was maintained and precisely what its nature was." (AP 245) 9. °Q. You have attempted in your report of 18 June to indicate what your views are on the probabilities as to how this mesothelioma was caused in this case, have you not? A. The history provided by the patient indicated possibilities of exposure at a certain period of time. I assume therefore, that there is a relationship of cause and effect between the development of mesothelioma and the exposure to agents that are capable of being incriminated in that development." (AB 245-6) 10. "A... I cannot rule out the possibilities that it [the 9-month period of employment with Hatrick in 1985-86] had that contributory effect". Q. Just given the history, the whole history that has been given to you by the plaintiff, Mr Walsh, you would not say that it is probable that that exposure was the material contribution to his current situation. A. No, I wouldn't say that, but I would also say that it was impossible for me to have any valid opinion on identifying any particular time frame or employment during his working life for that matter." (AB 246-7) 11. "A.... Maybe it is valid to think in terms of the proverbial straw that breaks the camel's back and I am not being facetious, I really don't know. I think the assumptions you ask me to make, all very reasonable, all very plausible, but I don 't know, so can I therefore say, well, yes, let's ignore that, maybe it was that exposure that was the was the proverbial straw on this camel 's back, I don 't know. Q. Does that mean... A. I think, what you are saying seems very plausible, and you are asking me, and I don 't know if I recall the precise words, but you asked me to say, so I agree that this is likely, in so many words, that 's.. Q. More probable than not. A. More probable than not, then, and I say that using those words, it seems reasonable the way I understand the words, 'probable', to use that word, but I'm asking you to bear in mind the qualification that I am suggesting is not irrelevant and that is that though it may not be probable that that had anything to do with it, it is quite possible and may be that there's a critical degree of additional exposure that plays a part in these things, I don't know, ''m surmising, ''m speculating and I think individual cases from a medical point of view, are not very good cases on which to speculate in this one." (AB 248) 12. "Q.... I want you to say whether, if you were given the added information, 50 the buffing machine had the effect of throwing into the face of the operator, in this case, Mr Walsh, of the buffing machine, those asbestos particles, even though it 8 UNREPORTED JUDGMENTS only be 10 per cent of the three weeks per annum that - for 10 years, would that added piece of information that I have just given to you as to the manner of the operation, assist in determining whether on the probabilities that work could be, and is by you, regarded as a materially contributing factor to the condition for which you have been treating him. A. Well, the answer is I don't know but I continue to feel that I need to assume in the absence of an ability to isolate a particular event or period of time from others, that all exposures may well have played a significant contributory role in the subsequent development of his malignancy. Q. Is that on the basis of this aggregation of exposure over a long period of time. A. It is on the assumption that people who are exposed over a long period of time, that that development of a malignant mesothelioma, is not only related to exposure to asbestos, but is also related to cumulative exposure to asbestos over a period of time." (AB 249-50) [Portion of this evidence is cited in the critical passage from the judgment of Curtis CCJ which has already been sent out.] Dr Joseph's evidence included the following passages: 13. "A. No one could say at what particular point he inhaled the particular fibres that caused his mesothelioma I mean, unless they had been tagged with a nuclear identification you couldn't possibly say which of those fibres was the cause. I mean, the exposure occurred over that period of time and any one of those days might have been the day on which he inhaled the fibres that got out to his pleura and caused the mesothelioma, because it 's the fibres that reach the pleura which cause the mesothelioma. (AB 704) 14. A. Well, it is cumulative in that the longer the exposure and the heavier the exposure the greater the dose of asbestos which enters the lung and therefore the greater the chance of fibres getting to the periphery of the lung where they would generate mesothelioma, so therefore in a sense it is cumulative. I mean, no one could put their finger on a particular instance and say it was this particular exposure on this particular day that he inhaled the asbestos fibres which ultimately caused the tumour." (AG 744) 15. "Q. In your report you, of course, determine that you believed the exposure at the Hunter District Water Board is more likely to be the one responsible. Is that correct. A. Correct. Q. Is that on the balance of probabilities. A. Yes. That 's on the balance of probabilities, having regard to the statement that he made, as reported to me, regarding his work and the length of time for which he was operating in that environment. Q. And the amount of exposure. A. Yes. I said both. The amount of exposure, the type of work and the length of time for which he was exposed." (AB 750-1) 16. "A.... you can have a latency of as long as 50 years.... Statistically the mean would be 30 years." (AB 751) 17. "A.... I know of a case where seven years was the latent period, but that's very unusual. It's very uncommon under 10 years and uncommon under 20 years." (AB 755) 18. "Q. Is the contracting of mesothelioma dose-related. URJ ICl AUSTRALIA OPERATIONS PTY LTD v WALSH and ORS (Mason P) 9 A. It is loosely dose-related. By that I mean people with relatively mild exposures to asbestos, as has happened in neighbourhood exposure which certainly wouldn't be a dose big enough to produce asbestosis, is sufficient to produce mesothelioma So - but the heavier the exposure to asbestos the more likely it is that the patient will develop a mesothelioma; but I'd like to make it clear that despite even heavy exposures which will produce asbestosis, not all those people get mesothelioma, and what factors determine which people shall get mesothelioma and which shall escape it, we do not know." (AB 858) 19. "A... there is a dose disease relationship, in other words, the greater the amount of asbestos which gets access to the lung and there is able to get out to the pleura the greater the risk of getting mesothelioma, even though a small exposure may do it a bigger exposure makes it more likely to occur, so I think you have got to take into consideration the whole picture and period of exposure but one also has to have - take cognisance of the latent period. I mean, for example, if a man had an exposure to asbestos 35 years ago that lasted, say a year, and he had a more recent exposure, say during the last 10 years, I'd have no hesitation in saying the first exposure was by far the more likely to be the one responsible, but you can't prove this in any way unless you were able to tag the asbestos fibres with radio isotopes to tell which had done the damage..." (AB 938) In addition to the passages set out above I have read those to which the Court was referred in the written submission of the first, second and fourth respondents. I do not think that any of those passages takes the matter any further. By reference to the numbered paragraphs set out above it is possible to state my conclusions fairly briefly. Read as a whole, Dr Schneeweiss was endeavouring to convey the view that he was primarily concerned with Mr Walsh as a patient (see esp §§7,8). Based on that patient's history, it was highly probable that his fatal mesothelioma derived from exposure from "some or all" of his employment situations involving the defendants (§1). Dr Schneeweiss did not purport to suggest that he understood the aetiology of mesothelioma (§§2, 4, 5, 10, 11, 12). Accordingly, when he spoke of the impact of any particular exposure he assumed causation (§§4, 5, 7, 9) or merely refused to exclude the possibility of causation (§§6, 10, 11,12). Nevertheless, like other expert witnesses in this and similar cases, he was able to indicate that factors such as dosage and lead time increased the likelihood of contracting the disease. The probabilities (in a statistical sense) clearly favoured liability being sheeted home to the parties who employed Mr Walsh before the fourth (Hatrick) and fifth (ICI) defendants did (see §§3, 5, 10). Dr Joseph's evidence was to similar effect as regards the greater likelihood of the earlier periods of employment being critical (see §§16, 17, 19). He, like Dr Schneeweiss, did not suggest he knew what caused mesothelioma (§§13, 14, 18) although he accepted that a latency period under 20 years was uncommon, and very uncommon if under 10 years (§17. See also §§15, 16). He readily conceded that exposure during the last 10 years was improbably the cause in a situation where there was evidence of significant exposure in the 35 year range (§19) All of this evidence supported clearly the findings of liability against the three defendants who employed Mr Walsh during the period 1964-1984. And it supported a sustainable conclusion that exposure during this period was probably the cause of the mesothelioma, notwithstanding the inability of any expert to posit the causative mechanism or to suggest the exclusive liability of a particular 10 UNREPORTED JUDGMENTS defendant. These findings are not challenged. They and the evidence supporting them should not be ignored when considering the case against the appellant. The trial judge concluded, in the passage set out, that all asbestos exposure is causative. He also found that the risk of developing mesothelioma was materially increased by the further exposure of Mr Walsh during his employment by Hatricks and the appellant. This later exposure was seen as possibly aggravating the impact of the earlier exposure by being cumulative upon the initial causative exposure. In my opinion, these findings were not open on the evidence given that neither expert espoused the total fibre theory or any other theory that suggested that mesothelioma was the result of a continuous cumulative set of circumstances in the sense discussed in cases such as Bonnington Castings Ltd v Wardlaw!° and McGhee v National Coal Board!! as interpreted by the majority of the House of Lords in Wilsher v Essex Area Health Authority!2 Each expert frankly admitted that he could not suggest what caused mesothelioma, and that when speaking of a greater or lesser likelihood he was addressing a mere statistical probability. When the key passages referring to "cumulative exposure" are examined, they show the two experts honestly and consistently reaffirmed their agnosticism on the matter: see §§4, 11, 12, 14. In misunderstanding this evidence the learned judge erred in the critical part of his reasoning. Even if the expert opinions offered evidence capable of sustaining a finding against the appellant, the judge should not have made such a finding having regard to the clear preponderance of evidence pointing away from the appellant. Since a finding of liability depended ultimately upon probability, the third paragraph of the passage extracted carries the seeds of its own destruction in the sentence stating that "the short answer to this argument is that without the later exposure, the seed may not (despite the probabilities) have flourished, either as soon, or at all'".13 I would therefore uphold the appeal. The burden of meeting the verdict against the appellant (which should be set aside) should be transferred to the second and fourth respondents roughly in proportion to their respective shares as apportioned by the trial judge. I would not disturb the apportionment awarded against the fourth respondent given its small size (5%) and the fact that its position is very similar to that of the appellant. As to costs, the parties who took an active part in the appeal submitted that the Court should address costs below and in the Court of Appeal in the light of the Court's conclusions on liability and apportionment. As previously indicated, it appears that no order was made below as to the costs of the proceedings in the Dust Diseases Tribunal. I therefore propose the following orders: 1. Appoint Noeline Mary Walsh as first respondent in place of the late John Michael Walsh. 2. Appeal allowed. 3. Judgment against appellant set aside. 4. Enter judgment in favour of the appellant. 10. [1956] AC 613. 11. [1973] 1 WLR 1. 12. [1988] AC 1074. 13. Emphasis added. URJ ICI AUSTRALIA OPERATIONS PTY LTD v WALSH and ORS (Meagher JA) 11 5. Order that the liability of the second and fourth respondents to contribute to the verdict in favour of the plaintiff below is varied by increasing the liability of the second respondent (Boral) from 25% to 27% and the liability of the fourth respondent (Ampol) from 65% to 68%. 6. Costs of the appellant and of the first respondent in relation to the proceedings below (unless previously ordered in relation to any matter) are to be borne by the second, fourth and fifth respondents in the proportions of 27: 68: 5 respectively. 7. Costs of the appellant and of the first respondent in the appeal are to be borne by the second and fourth respondents in the proportions of 30:70 respectively. Meagher JA The late Mr John Michael Walsh, who was the applicant below and whose executrix was the first respondent in these proceedings, died of mesothelioma. He had five different employers from 1964 to 1996, when he retired. One was Boral Ltd, the second respondent in this appeal, for whom he worked from 1 April 1964 until 1 January 1969. Another was Ampol Refineries (Matraville) Ltd, the fourth respondent, for whom he worked from 1 June 1969 to December 1974. Another was a partnership of six natural persons who traded under the name "Coltec Services". They are the third respondent, and they employed him from March 1975 until February 1976. From February 1976 until October 1984 he worked once again for Ampol, the fourth respondent. For nine months in 1985 his employer was AC Hatrick Chemicals Pty Ltd, the fifth respondent. Finally, for over ten years, from January 1986 until may 1996 he worked for the appellant. His Honour, Curtis J, found that the combined negligence of all five employees caused the hapless Mr Walsh to contract his mesothelioma. He computed Mr Walsh's damages at $390,947. His Honour ordered that this sum be apportioned (in effect) between the appellant and the second, fourth and fifth respondents in various amounts. Of all the employers the present appellant alone appeals. Many of the issues are no longer in dispute. Thus, it is not in dispute that, in each period of employment, Mr Walsh was heavily exposed to asbestos; nor that such exposure, in general terms, can and does cause mesothelioma; that the probable link between asbestos and mesothelioma has been known generally for a long time; that the employers each knew or should have known of it; and that, by chosing to take no steps to prevent the exposure of Mr Walsh to asbestos, negligently caused his contraction of the fatal disease. Nor was the ultimate figure of $390,947. in dispute. What is, I think, of some importance to stress is the current state of medical knowledge about mesothelioma. The evidence of all the doctors in the trial below is to the effect that it cannot be demonstrated with scientific certainty that exposure to asbestos does cause mesothelioma, although the anecdotal and statistical information available tends strongly to that conclusion; and that there are many mysteries about the aetiology, cause, behaviour, and prognosis of that disease. It is also agreed that there is often a "lead time" of many years between contracting the disease and the disease making itself manifest. What I think the evidence also proves is that it is the continuity of exposure which causes the disease, not any one incident. The finding of Curtis J that the experience of Mr Walsh in working for the appellant was at least a contributory cause of his mesothelioma is challenged by the appellant. There seems to be two grounds which are involved in this submission. The first is that the 'lead time" excluded the possibility that any 12 UNREPORTED JUDGMENTS exposure to asbestos in the appellant's premises was causally related to the mesothelioma Indeed, this was asserted dogmatically by a Dr Gandevia. His Honour disbelieved Dr Gandevia He had to, because a Dr Schneeweiss proved that he had personal experience with a patient suffering from the disease where the "lead time" was between seven and eight years. Another doctor, Dr Joseph, had experienced a plaintiff suffering from mesothelioma when the lead time was as short as six years. This ground must, therefore, fail. The second ground for the submission should now be examined. It is simply that there is no evidence which connects the disease with the appellant. In this regard, also, his Honour accepted the evidence of Dr Schneeweiss and Dr Joseph his Honour said: "Mr Schneeweiss, in answer to a question as to whether the exposure in the employ of the 4th and 5th defendants materially contributed to the development of the plaintiff's mesothelioma, said this "Well, the answer is, I don't know, but I continue to feel that I need to assume in the absence of an ability to isolate a particular event or period of time from others, that all exposures may well have played a significant contributory role in the subsequent development of his malignancy." If any exposure materially contributed to the risk of contracting the disease, that exposure is as causally relevant as any other exposure which in fact materially contributed to the disease. It is not necessary that the plaintiff apportion the extent of contribution because the law gives him, as a matter of policy, a complete remedy against each defendant." This is certainly what Dr Schneeweiss said. For example, in his report of 18 June 1996 he said: "T accept the history provided by Mr Walsh in relation to the extent of asbestos exposure previously experienced by him as being the aetological causation of his negligent mesothelioma and, having regard to the time intervals involved, would postulate on the balance of probabilities that this condition is causally related to some or all of his employment history between 1964 and 1996." Later, in cross-examination, the doctor said it is the "aggregate which matters", and further "that the development of a malignant mesothelioma not only is related to exposure to asbestos but is also related to cumulative exposure to asbestos ever a period of time." He also said that the disease is dose-related because the heavier the exposure the more likely it is the patient will develop mesothelioma; that no exposure is innocent and each exposure is a cause of mesothelioma; that all asbestos exposure is causative of the disease; and that no single exposure could be excluded as irrelevant to the development of the condition/. On this, and other like, evidence, it is no wonder his Honour found what he did. Mr Maconachie QC., learned senior counsel for the appellant, placed some reliance on what Taylor J said in Australian Iron & Steel Ltd v Connell (1959) 102 CLR 522 at 531, viz: "No doubt acceptance of the propositions in question may justify a conclusion that exertion may hasten the death of a person whose coronary vessels are impaired of diseased but they are of little, if any, assistance when it is necessary to attempt to assess the inter-relation of exertion and a subsisting coronary disease where, in any particular case, death has resulted. In any such case 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 to be determined by the evidence in the case" URJ ICI AUSTRALIA OPERATIONS PTY LTD v WALSH and ORS (Handley JA) 13 In this regard be pointed to various quotations in the evidence when the language is couched in terms of potential not actual damage. However, the analogy does not work. In Connell's Case the evidence in question could have been obtained. The science of cardiology is sufficiently advanced to answer unequivocally whether exertion does or does not cause or contribute to a heart failure in a particular case. In cases of mesothelioma, where medical knowledge is still in its infancy potentiality rather than actuality must be embraced. Nor, of course, does the case bear any analogy to the cases in tort where one of two acts must be negligent but one cannot say which (eg., two hunters simultaneously shooting similar guns). Different independent simultaneous causes are very different from a continuous cumulative set of circumstances. In my opinion the appeal should be dismissed with costs. Handley JA I agree with Mason P. 1. Appoint Noeline Mary Walsh as first respondent in place of the late John Michael Walsh. Appeal allowed. Judgment against appellant set aside. Enter judgment in favour of the appellant. Order that the liability of the second and fourth respondents to contribute to the verdict in favour of the plaintiff below is varied by increasing the liability of the second respondent (Boral) from 25% to 27% and the liability of the fourth respondent (Ampol) from 65% to 68%. 6. Costs of the appellant and of the first respondent in relation to the proceedings below (unless previously ordered in relation to any matter) are to be borne by the second, fourth and fifth respondents in the proportions of 27: 68: 5 respectively. 7. Costs of the appellant and of the first respondent in the appeal are to be borne by the second and fourth respondents in the proportions of 30:70 respectively. wRWN Counsel for the appellant: J E Maconachie QC/G A Farmer Solicitor for the appellant: Connery & Partners Counsel for the first respondent: P M Hall QC/D G Stewart Solicitor for the first respondent: Jones Staff & Co Counsel for the second respondent: A R Ashburner Solicitor for the second respondent: Hunt & Hunt Counsel for the third respondent: I Denham, Sol (submitting appearance) Solicitor for the third respondent: Moray & Agnew Counsel for the fourth respondent: G J Parker Solicitor for the fourth respondent: P W Turk & Associates