Seltsam Pty Ltd v Mcguiness; James Hardie & Coy Pty Ltd v Mcguiness

[2000] NSWCA 29

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(Decision by: Davies AJA)

Seltsam Pty Ltd
vMcguiness; James Hardie v Coy Pty Ltd v Mcguiness

Court:

Judges: Spigelman CJ
Stein JA

Davies AJA

Subject References:
NEGLIGENCE
proof of negligence
causation
whether exposure to asbestos caused renal cell carcinoma
use of epidemiological studies EVIDENCE
opinion evidence
expert opinion
Evi-dence Act 1995 (NSW) s79 DUST DISEASES
Appellate Jurisdiction of Supreme Court
Dust Diseases Tribunal Act 1989 s32

Legislative References:
Compensation Court Act 1984 - The Act
Courts Legislation Amendment Act 1998 - The Act
Dust Diseases Tribunal Act 1989 - The Act
Evidence Act 1995 - The Act
Interpretation Act 1987 - The Act

Case References:
-

Hearing date: 2 and 3 August 1999
Judgment date: 7 March 2000

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Decision by:
Davies AJA

[265] As the Chief Justice and Stein JA have dealt with all the issues in the appeal, I limit my comments to the issue of causation, on which I agree with the reasons and conclusions of the Chief Justice. I agree with the Chief Justice and Stein JA on the nature of the appellate jurisdiction.

[266] This appeal is one in which it is important for an appellate judge to consider carefully the issues and the material that were before the trial Judge. Although the trial Judge, His Honour Judge Maguire, at the end of a week's hearing of a case which had been brought on as a matter of urgency, gave an impressive judgment, an appellate judge necessarily has more time available in which to consider the matter.

[267] As Stein JA has pointed out, the reasons for judgment show that the trial Judge treated the case essentially as if it turned on a contest between the two epidemiologists, Dr Margaret McCredie on the one hand and Professor Joseph McLaughlin on the other. The trial Judge preferred Dr McCredie's view, in particular because he considered that a statement expressed in a study, in which both Dr McCredie and Professor McLaughlin had participated, was inconsistent with the view which Professor McLaughlin was expressing to the Court. In my view, for reasons I shall later state, that approach was wrong. In my opinion, as a result of His Honour's approach, matters put on behalf of the present appellants, the employers, were not considered.

[268] In the circumstances of this case and having regard to the issues, which are ones that can be resolved from a reading of the medical reports and of the transcript of the evidence, and in which the benefit that a trial Judge may have from hearing the witnesses give their oral evidence has little application, I consider that I should examine the matter for myself. Such an approach was adopted by each member of the Court in Bendix Mintex Pty Ltd v Barnes (1997) 42 NSWLR 307. See, particularly, Mason P at p319 and also State Rail Authority of New South Wales v Earthline Constructions Pty Ltd (In Liq) (1999) 73 ALJR 306.

[269] I need not discuss at length the principles of causation which were fully examined in Bendix Mintex Pty Ltd v Barnes. The present case does not raise the issue which led to the dissent of Stein JA in that case. The following are principles enunciated in Bendix Mintex Pty Ltd v Barnes. Causation is a question of fact to be determined by the application of commonsense to the facts of each case: see March v E & M H Stramare Pty Ltd (1991) 171 CLR 506; Bennett v Minister of Community Welfare (1992) 176 CLR 408; Bendix Mintex Pty Ltd v Barnes at p315-p316, p335, p345. In a negligence claim, it is sufficient for a plaintiff to establish that his or her injuries were caused or materially contributed to by the defendant's wrongful conduct: see Kilgannon v Sharpe Bros Pty Ltd (1986) 4 NSWLR 600; Bendix Mintex Pty Ltd v Barnes at p311, p335, p345. The onus is on the plaintiff to prove causation on the balance of probabilities: see Bonnington Castings Ltd v Wardlaw [1956] AC 613; McGhee v National Coal Board [1973] 1 WLR 1; Wilsher v Essex Area Heath Authority [1988] AC 1074; March v E & M H Stramare Pty Ltd; Bendix Mintex Pty Ltd v Barnes at p315, p339, p349. The onus is not discharged by establishing that a particular matter cannot be excluded as a cause of the injury: see Bendix Mintex Pty Ltd v Barnes at p318, p339.

General Facts

[270] Mr McGuiness was born on 25 November 1934 and was 62 years of age at the time of the trial. From 1950 until 1984, he worked at a factory at Rosehill in which asbestos was used, inter alia, in the manufacture of fibro-cement sheeting and mouldings. That factory had been conducted originally by Wunderlich Ltd and was taken over by James Hardie & Coy Pty Ltd in 1977. In 1984, Mr McGuiness was transferred to the Dispatch Section of the James Hardie Camellia Fibro Plant and he worked there until he ceased work in April 1991. In that Plant, large quantities of flat sheet and corrugated fibro were stored and moved. It appears that, in the early years, Mr McGuiness may have come into contact with both crocidolite (blue asbestos) and chrysotile (white asbestos), but for the most part he encountered chrysotile.

[271] The proceedings in the District Court commenced in 1993 after Mr McGuiness had been diagnosed as having pleural plaques, which were presumed to have been asbestos related. However, the plaques did not develop but remained benign and were not incapacitating. In 1997, Mr McGuiness was diagnosed as suffering from renal cell cancer of the left kidney. This was a fast growing malignancy which spread to the spine and was invading the lung. At the time of the trial, Mr McGuiness had only a short time to live.

The Nature and Sequence of Events

[272] It is not in dispute that renal cell cancer has a cause or causes. It is not in dispute that Mr McGuiness, in the course of his working life, would have inhaled and may have ingested asbestos fibres and dust and that, if the intake of asbestos was a cause of renal cell cancer, then the period over which the inhalation and ingestion of asbestos occurred was consistent with the development of the cancer.

[273] However, consistency is not enough. Although renal cell cancer is one of the less frequent cancers, it is common throughout the population. Moreover, Mr McGuiness was at an age at which renal cell cancer is commonly found and, although the cause of most renal cell cancers is unknown, there were at least two factors which were generally accepted as having a causal relationship with renal cell cancer. One was obesity, from which Mr McGuiness suffered throughout most of his life, and another was smoking. Mr McGuiness was a moderate smoker.

[274] These basic facts do not support an inference of a causative link between asbestos and Mr McGuiness' renal cell cancer, merely an inference that a connection was possible because of Mr McGuiness' long encounter with asbestos.

Medical Facts

[275] The following are the principal facts concerning renal cell cancer which were referred to in the evidence and which appear to be uncontroversial, notwithstanding that they were not stated by the trial Judge:

(1)

Most cancers, particularly environmental cancers, are thought to result from successive insults to the DNA structure of cells until eventually a catalyst or event occurs which causes a change in a cell, this cell becoming a rogue cell which multiplies rapidly.

(2)

In renal cell cancer, where there is no predominant risk factor, the preconditioning is " most likely to be a whole swathe of causes ".

(3)

Renal cell cancer appears to have a relationship with aging. Most renal cell cancers are found in men aged in their 60's and 70's.

(4)

Asbestos is a known causal agent of mesothelioma, asbestosis and lung cancer. As Mr McGuiness' cancer was located in the substance of his kidney, not in the outer lining, it is appropriate to look at asbestosis and lung cancer rather than at mesothelioma. Asbestosis and lung cancer, but not mesothelioma, are dose response conditions.

(5)

Lung cancer appears to have a relationship with asbestosis. Asbestosis may be a necessary or usual precondition to lung cancer. Mr McGuiness suffered from neither asbestosis nor lung cancer, or at least showed no signs thereof.

(6)

Obesity and smoking are accepted causes of renal cell cancer; but the risk ratios of about 1.5 to 2 are relatively low. The reasons for the relationships are not known; but it is thought that there may be something in tobacco, such as an oxidant, or in the diet, which may be the contributing factor. Diet is suspected but not proven to contribute to renal cell cancer. The ingestion of a number of chemicals and minerals which are known carcinogens is a suspected cause. Hypertension is also suspected of having a causal relationship. However, although many factors are suspected to contribute to renal cell cancer, it is a cancer found in the community generally, and no predominant cause has been identified. In most cases of renal cell cancer, no cause is identified.

(7)

Although asbestos is a known carcinogen or causal agent of mesothelioma, asbestosis and lung cancer, it has not been shown to have that effect in relation to other parts of the body. For example, contact between asbestos and the skin does not appear to cause cancer. In laboratory tests, the injection of asbestos into the kidneys of rats has been shown to cause cancer. However, such experiments are not a reliable indicator of the human experience.

(8)

Asbestos has been found throughout the body including the brain, the heart, the lymph nodes, the adrenal glands, the kidneys and elsewhere. Asbestos may enter the body either through inhalation or by way of ingestion through the gut.

(9)

Long thin asbestos fibres greater than 8 micrometres in length and certainly more than 5 micrometres in length appear to be necessary to induce carcinomas or mesothelioma. The fibres recovered from renal tissue have been extremely short. A paper by Patel-Mandlik recorded the range of fibre in renal tissue as between 0.1 micrometre through to a maximum of 2.5 micrometres with the great majority of fibres falling within the range of 0.4 to 0.6 micrometres.

(10)

Although the contact which Mr McGuiness had with asbestos was undesirably high and was described by the trial Judge as " heavy " and may well have been a, or the, cause of his pleural plaques, it did not lead, in his case, to mesothelioma, asbestosis or lung cancer.

(11)

A fine needle aspiration taken from Mr McGuiness' left kidney did not disclose the existence of asbestos fibre. The biopsy was, however, a very small section.

[276] The above points were the main facts which, together with the epidemiological evidence, were relied upon by the medical practitioners who gave evidence in Mr McGuiness' case. They do not seem to me to justify an inference that asbestos had a probable, as distinct from a possible, causal connection with Mr McGuiness' renal cell cancer.

The Medical Practitioners

[277] The medical experts called on behalf of Mr McGuiness drew an inference of probability from the fact that there are likely to be many causes which contribute to bring about renal cell cancer, from the fact that, as asbestos can reach the kidneys, it is possible that asbestos exposure was a contributing cause of Mr McGuiness' cancer and from the fact that asbestos is a known carcinogen. On the other hand, the employers' experts pointed out that, although asbestos has been found in many parts of the body, including the brain, the heart, the lymph nodes and so on, it has not been identified by practitioners or by pathologists working in those fields as a cause of cancer in those areas or, more importantly, as a cause of renal cell cancer.

[278] The employers' experts pointed to the fact that asbestos has not been shown to cause cancer other than mesothelioma, asbestosis and lung cancer. They further suggested that, even if asbestos could cause renal cell cancer, it was improbable that it did so in Mr McGuiness' case. They pointed out that, if asbestos caused renal cell cancer, the cancer would be dose related and therefore, if the asbestos were inhaled, they would expect there to be at least a sufficient inhalation to cause asbestosis. Mr McGuiness did not show signs of asbestosis. The degree of pleural plaque formation is a reasonably good guide to the degree of asbestos exposure. Mr McGuiness' plaques were minor. They suggested that, if the asbestos had been ingested, by being swallowed with other dust, it would have been filtered passing through the gut into the bloodstream and then to the kidneys. Asbestos is not an established cause of stomach cancer and the asbestos fibres found in the gut have been small, not of the length of the fibres known to cause cancer in the chest.

[279] I do not propose to set out in detail the evidence of each particular medical practitioner. On behalf of Mr McGuiness, evidence was called from, inter alia, Dr M W Burns, a Thoracic Physician, and Dr B J Nankivell, a Consultant Renal Physician. Both expressed the view that the contact which Mr McGuiness had with asbestos in the course of his work was a probable cause of his renal cell cancer. Both expressed their opinions by reference to the epidemiological evidence and to the fact that asbestos was a carcinogen. Dr Burns seems to have relied principally upon the epidemiological evidence, including a study by Maclure, in respect of which the author later recanted. Dr Nankivell relied, not only upon the epidemiological material, but also upon the nature of cancer, the consistency of the time delay in the case of Mr McGuiness and the known effects of asbestos. Neither doctor gave evidence that he had personally encountered a case where asbestos fibres had been found to be associated with renal cell cancer. Indeed, Dr Nankivell confused chrysotile, the white asbestos, with crocidolite, the blue asbestos.

[280] Called on behalf of the employers were, inter alia, Professor D W Henderson, a Specialist Pathologist with an interest in epidemiology and who for many years has been concerned with the problems of asbestos related diseases and neoplasia in particular, Professor D A Ferguson, a Consultant Occupational Physician and an Emeritus Professor at the University of Sydney who has specialised in the field of occupational medicine, Associate Professor A B X Breslin, a Consultant Thoracic Physician, and Dr J Lee, a Thoracic Physician. These medical practitioners relied upon the epidemiological evidence but their evidence was not limited to that. The effect of their evidence was that the medical profession has not accepted that asbestos is a cause of renal cell cancer. Dr Breslin said, "[ T ] he majority of authorities at this stage won't accept that it is established that renal cancer is caused by asbestos exposure " and "[ I ] t is a possibility and ... that is why all these studies have been done trying to establish whether it actually happens rather than just a possibility ". Dr Breslin said that he had never seen a renal cancer that he thought was due to asbestos exposure. The employers' experts considered that the connection between asbestos and renal cell cancer was unlikely to be found because the conditions that had been observed in relation to asbestosis and lung cancer, including the length of the fibres and the body's response to those fibres, had not been observed in kidneys, where such asbestos fibres, as have been found, have been of a very small size. Moreover, the employers' experts thought that, even if asbestos could cause renal cell cancer in some cases, it was unlikely that asbestos inhalation or ingestion was a contributing factor to Mr McGuiness' cancer, as he had not inhaled sufficient asbestos to cause lung cancer or asbestosis.

[281] To my mind, the evidence given by the employers' medical experts is the more persuasive. Dr Burns and Dr Nankivell considered that, as it is likely that the development of renal cell cancer has many causes, then asbestos, which is known to cause cancer elsewhere in the body, was probably a cause of Mr McGuiness' cancer. That is clearly a tenable view. However, I am persuaded that the weight of the medical evidence is against it. I am also influenced by the fact that there is no evidence from any medical expert that he or she has encountered in the course of his or her practice, a case or cases of renal cell cancer which he or she has attributed to asbestos. Anecdotal evidence to that effect, such as one encounters in other areas of medico-legal disputes, is absent, notwithstanding the long history of the mining and use of asbestos in Australia. I am also influenced by the point that, if Mr McGuiness had encountered sufficient asbestos to cause cancer, one would have expected him to show signs of asbestosis or lung cancer, for their connection with asbestos is a strong one. Renal cell cancer is considered to be, in relation to environmental carcinogens, a dose related cancer.

The Epidemiological Evidence

[282] Although His Honour did not expressly say so, he appears to have taken the view that, absent support from the epidemiological studies, the medical evidence would not justify a finding of causation. The trial Judge, however, then treated the matter as if it were a contest between the evidence of Dr Margaret McCredie on the one hand, who said that, in her view, on the epidemiological evidence available, Mr McGuiness' exposure to asbestos was a cause of his renal cell cancer, and that of Professor Joseph McLaughlin, on the other hand, who expressed the view, inter alia, that the epidemiological evidence justified the conclusion that a causal relationship between asbestos and renal cell cancer did not exist. His Honour's approach excluded consideration of the view that the epidemiological material was inconclusive.

[283] There is, indeed, much to be said for the view that the epidemiological evidence is inconclusive, that it does not show positively either that there is a causal connection between asbestos and renal cell cancer or that there is no such connection.

[284] Most studies, and there have been many of them, have found no association between asbestos and renal cell cancer. However, the Selikoff study in 1979, the Enterline study in 1987 and the Maclure study in 1987 reported a link between asbestos and renal cell cancer. The lastmentioned report was later thought to have had a flaw in its methodology and Maclure recanted. Dr McCredie, who has been connected, inter alia, with the Cancer Epidemiology Research Unit at the New South Wales Cancer Council, later participated with J H Stewart in a study of asbestos and kidney cancer in New South Wales in respect of the years 1989-1990. That study, which was a population-based study, reported that exposure to asbestos significantly increased the risk of renal cell cancer by a factor of 1.6, that is to say that there was a 60 per cent increase in risk.

[285] That particular study was undertaken as part of an international study into renal cell cancer, a study which was headed by J S Mandel and in which Dr McCredie, Professor McLaughlin and others participated. In that study, called "the Mandel study", there were six study centres in five countries: Australia, Denmark, Germany, Sweden and the USA. There was a common study protocol and the instruments for data collection were similar. That overall study found an increase risk of renal cell cancer associated with exposure to asbestos and placed the risk at 1.4. The vital conclusion of the Mandel study read as follows:

"Several investigators have found increased risks of kidney cancer associated with exposure to asbestos (Selikoff et al, 1979; Enterline et al, 1987; Maclure, 1987; Smith et al 1989). Experimental evidence lends support to a causal link. Asbestos fibres have been found in the kidneys of individuals with high exposures (Huang et al, 1988) and in the kidneys of exposed animals (Kanazawa et al, 1970). Finn and Hallenbeck (1985) found more asbestos fibres in the urine of asbestos workers than in non-exposed controls. Case-control studies not showing an association with asbestos exposure had small numbers of exposed workers (McLaughlin et al, 1984; Yu et al, 1986; Asal et al, 1988; Brownson, 1988; Partanen et al, 1991; McLaughlin et al, 1992). Our study, with 200 exposed cases, provides additional evidence that asbestos increases the risk of kidney cancer. Nevertheless, further research of asbestos-exposed workers is needed to demonstrate a relationship with either duration of employment or amount of exposure before a causal association can be confidently concluded."

Note the last sentence which indicated that, while the study itself showed an increased risk, further research was required to ascertain whether the causal relationship existed.

[286] There were good reasons for the qualification which the authors of the report put upon their finding. The first was that the risk ratio was a modest one. The risk ratios in relation to mesothelioma and lung cancer are of a different order entirely. Secondly, the study was a population-based case-study, a form of study which the report itself acknowledged was not the most accurate or efficient study method for ascertaining a specific occupational risk. Thirdly, the study did not show a dose related effect. Indeed, the McCredie-Stewart study reported that the risk for renal cell cancer was fivefold higher in those whose exposure began after rather than before 1956. The finding was the reverse of that which would have been expected. Finally, the Mandel study was only one of a number of studies which had been undertaken. It was one of the studies which reported a positive relationship between asbestos and renal cell cancer, but the majority of studies were to the contrary.

[287] In epidemiology, consistency is important. Epidemiology seeks to arrive at a conclusion with respect to a medical issue through the use of mathematical techniques. Neither the McCredie-Stewart study nor the Mandel study established, as a fact, that exposure to asbestos was causally related to renal cell cancer. Neither the McCredie-Stewart study nor the Mandel study expressed itself in that way. Both studies reported an increased risk. There is no question about that. But they were studies which needed to be taken into account with other studies before a general conclusion could be reached. They increased the possibility that a causal relationship existed. But they did not establish that it did so.

[288] In two other studies reported at about the same time, one being a follow-up study of the Wittenoom cohort by N H de Klerk and others, which was published in 1994, and the other a Canadian study on Cancer Mortality in Chrysotile Mining and Milling by Douglas Liddell also published in 1994, no increased risk was found relating asbestos to renal cell cancer.

[289] The view that the epidemiological studies show no more than a possibility that asbestos may be related to renal cell cancer has been expressed in the textbooks. A work by Richard Doll and Julian Peto in 1986 on Asbestos-Related Malignancy concluded in relation to renal cell cancer, " In the absence of any positive experimental evidence these data [earlier studies including the Selikoff study] do not, in our opinion, justify the belief that asbestos can cause this type of disease ". In 1992, Professor D Greenberg and Professor V L Roggli, writing on the pathology of asbestos-associated diseases said, in relation to renal cell cancer, " Overall, in the authors' opinion, the balance of the evidence available at present does not support an association between asbestos exposure and renal cell carcinoma ." More recently, in Cancer Epidemiology and Prevention, of which the editors were Schoddenfeld and Fraumeni, published in 1996, in a chapter on renal cancer by McLaughlin, Blot, Devesa and Fraumeni Jr, the following was stated:

"Unlike bladder cancer, the most common tumor of the urinary tract, renal cell cancer is not generally considered an occupationally associated tumor. However, asbestos has been linked to kidney cancer in several studies. Two cohort studies, one of insulators (Selikoff et al, 1979) and one of asbestos products workers (Enterline et al, 1987), reported significantly elevated mortality rates for kidney cancer. An association between asbestos exposure, mostly from work in shipyards, and renal cell cancer was suggested in a Boston-area case-control study (Maclure, 1987). There is some evidence from autopsy surveys and animal studies that asbestos fibres can be deposited in the kidney (Smith et al, 1989). Most case-control studies of renal cell cancer have found no association with asbestos exposure (McLaughlin et al, 1984; Yu et al, 1986; Goodman et al, 1986; Asal et al, 1988b; Brownson, 1988; Partanen et al, 1991), although their power to detect risks for asbestos exposure is generally low because of the small number of exposed workers. However, case-control studies from Australia (McCredie and Stewart, 1993) and Denmark (Mellemgaard et al, 1994d) observed elevated risks for self-reported exposure to asbestos."

That chapter was written before the Mandel report was issued, but subsequent to the McCredie-Stewart study.

Material Considerations

[290] The evidence of Dr McCredie which the trial Judge accepted was that, " On the balance of probabilities , ... exposure to asbestos materially contributed to the causation of renal cell carcinoma in this [ Mr McGuiness' ] case ". The evidence of Professor McLaughlin which the trial Judge rejected, was that, " On the balance of probabilities ... His [ Mr McGuiness' ] exposure to asbestos played no role in the development of his cancer ". However, it was not necessary for His Honour to choose between these two views. Dr McCredie and Professor McLaughlin were epidemiologists. Another view was that the epidemiological evidence was inconclusive. Studies other than the Mandel study were relevant and so was the detailed medical evidence.

[291] The trial Judge unfortunately took a narrow view of his function. His Honour said, inter alia:

"No Common Law judge is an expert in epidemiology. Even if one were, he would be required to leave his epidemiological hat on the peg when coming to judge any case, even one where epidemiology lay at its very heart. ... I propose not to examine or deal with all or indeed any of the particular criticisms, advanced by Mr McIntyre of counsel and Mr Burbidge of Queens Counsel for their respective clients [the employers]. These matters are matters which if I were an epidemiologist I might look to, in appraising the work of another epidemiologist. That is not my task." (emphasis added)

[292] As a result of this narrow approach to his task, the trial Judge turned his attention to the Mandel study, which he said was " at the heart of the issues that I must determine ". His Honour then rejected Professor McLaughlin's evidence, set out above, on the ground that it was inconsistent with the Mandel study, as that study has reported a positive relationship. To approach the matter in that way was to fail to consider the Mandel study in its context, to fail to take account of the criticisms which Professor McLaughlin and others had made of its results and to fail to consider whether the epidemiological evidence as a whole supported the claimed connection between asbestos and renal cell cancer. The trial Judge deliberately shut his mind to these matters considering it not to be part of his function to do so.

[293] By concentrating his attention on the words of the Mandel study, the trial Judge also excluded from his consideration the evidence given by the employers' medical experts that the medical profession generally has not accepted that asbestos is a cause of renal cancer and, further, that the conditions which had been observed in relation to asbestosis and lung cancer had not been observed in relation to the kidneys. Nor did the trial Judge appear to take into account many of the medical facts I have set out above or of the view that it was unlikely that Mr McGuiness' renal cancer would have been caused by asbestos as his exposure to asbestos had not led to asbestosis or lung cancer. Epidemiological results must be examined with care if they appear to be inconsistent with known medical or biological facts.

[294] The "Bradford-Hill Criteria" which set out relevant factors against which epidemiological results should be examined are cited in Reay v British Nuclear Fuels (1994) 5 Med LR 1 at 13-14. Amongst those factors, the strength of the association reported and the need for consistency, for biological plausibility and for dose response are emphasised.

[295] His Honour, however, did not consider the Mandel study in the context of the evidence as a whole, or even in the context of the epidemiological evidence as a whole. By excluding from his consideration such of the epidemiological evidence and of the medical evidence as threw doubt upon the result of the Mandel study, His Honour excluded important material from his consideration.

[296] The trial Judge also failed to point out that the finding of the Mandel study, an increased risk of 1.4, which was a modest increase in risk, was not a strong basis for a finding that asbestos was a cause of cancer in the particular case, Mr McGuiness' case, particularly in light of the fact, to which I have already referred, that in most cases of renal cancer no cause is identified. It is a cancer found in the community generally, particularly amongst men in their 60's and 70's.

[297] Contrary to the approach taken by the trial Judge, the duty of a trial judge is to consider the substance of the matters before him and to make all relevant findings of fact, whether or not they be of a technical nature. As Sir Owen Dixon said in his address on "Science and Judicial Proceedings", Jesting Pilate at p16, p22:

"When a judge is confronted with some question which depends upon a scientific inquiry however ill equipped he may be for the task, he is expected to acquire from the evidence of experts a sufficient knowledge of the subject to make him appreciate and even form a judgment upon the scientific facts, inferences and deductions which contribute to a correct solution to the question.

.....

There is no escape from the general necessity of investigating difficult and complicated sets of facts, and these can never be separated from considerations including any special branch of knowledge which may affect them."

In Mifsud v Campbell (1991) 21 NSWLR 725, at 728, Samuels JA put the matter succinctly when he said:

"[I]t is an incident of judicial duty for the judge to consider all the evidence in the case."

Conclusion

[298] In my opinion, the current state of the epidemiological evidence, as disclosed by the evidence of this case, is that a causal relationship between asbestos and renal cell cancer has not been established. Some studies have shown a positive relationship. The McCredie-Stewart and the Mandel studies showed a modest increase in risk. However, taking the epidemiological evidence as a whole, the position is that the link between asbestos and renal cell cancer remains a possibility, which has not been established as a matter of probability. In this circumstance, I would not accept the evidence of Dr McCredie that, " On the balance of probabilities , ... exposure to asbestos materially contributed to the causation of renal cell carcinoma in this [ Mr McGuiness' ] case ".

[299] In my opinion, the trial Judge placed undue weight on the Mandel study. I do not read that study as expressing a view other than that the study itself showed a positive causal relationship between asbestos and renal cell cancer, the risk factor being 1.4. I do not read the study as reporting that the causal relationship had been established on the balance of probabilities. Not only did the study itself not say that, but it was only one of a large number of studies. Its results had to be assessed in the light of its findings, the nature of the study, the inconsistency in the dose relationship and, finally, the inconsistency of the study with most other epidemiological studies. In my opinion, the study was written in the context that all these matters would have to be taken into account. Its conclusions should be read accordingly.

[300] I am, moreover, of the view that, having regard to both the epidemiological evidence and the medical evidence to which I have referred and which I need not repeat, it would be wrong to draw an inference of causation in this particular case.

[301] It follows, in my opinion, that the evidence before the Court does not justify a finding, on the balance of probabilities, that asbestos exposure was a cause of Mr McGuiness' renal cell cancer. Although I have discussed the issue under several headings, I have, nevertheless, considered the totality of the evidence in coming to this view.

Orders

[302] I would allow the appeal. I agree with the orders proposed by the Chief Justice.