20 In the same case, Windeyer J said (at 641):
I pass then to the next, and I think more difficult, question, was this aggravation or deterioration contributed to by her employment? This requirement of the Act is not satisfied by showing only that a worker suffering from some disease would or might have suffered less severely if he had not been employed at all. When the Act speaks of "the employment" as a contributing factor it refers not to the fact of being employed, but to what the worker in fact does in his employment. The contributing factor must in my opinion be either some event or occurrence in the course of the employment or some characteristic of the work performed or the conditions in which it was performed.
21 The appellant submits that Bishop CCJ erred when he cited and applied the passage in the judgment of Windeyer J as distinct from that of the judgment of Kitto J. I confess that I see no difference of substance between the two judgments on this point. Each of their Honours was accepting that what Kitto J described as "the inherent features or essential incidents of the employment" was relevant, employment in this context being a reference to the worker's actual contract of employment. But the thrust of the two passages was to emphasize that "employment" in the context extended to what the worker was in fact doing in his or her employment.
22 The worker correctly submits that the words "employment concerned" in s9A reinforce the view that it is the work activity in which the worker was engaged at the time of injury that is relevant. The ultimate question is whether that activity or task was a substantial contributing factor to the injury, bearing in mind that the concept of "a substantial contributing factor to an injury" is exegeted in subsections (2) and (3) of s9A.
23 Bishop CCJ did not err in this regard. He clearly understood that the event which caused the injury was an act done in the worker's employment and he held that the injury was itself suffered in the course of the worker's employment within the meaning of s4.
24 The appellant further submits that Bishop CCJ erred in his understanding of the concept of "a substantial contributing factor to the injury". It is submitted that he erred in his statement that "the mere fact that the applicant did what she did when she did … is not sufficient of itself to make the employment a substantial contributing factor to the injury". This is said to overlook the guidance in various judgments in Favelle Mort Ltd v Murray (1976) 133 CLR 580.
25 The provision in question in Favelle Mort was the definition of "injury" in s6 of the Workers' Compensation Act 1926 which included "a disease which is contracted by the worker in the course of his employment whether at or away from his place of employment and to which the employment was a contributing factor". There is an obvious danger in applying discussion as to the meaning of "a contributing factor" in this definition to the meaning of "a substantial contributing factor" in the context of s9A, with the additional guidance to be found in subsections (2) and (3) of that section.
26 The term "substantial" may have various shades of meaning. Having regard to the context, it may mean "large or weighty" or "real or of substance as distinct from ephemeral or nominal" (Tillmanns Butchery Pty Ltd v Australasian Meat Industry Employees' Union (1979) 42 FLR 331 at 348 per Deane J; Wong v Silkfield Pty Ltd (1999) 73 ALJR 1427 at [27]).
27 Here the word "substantial" qualifies "contributing factor". Obviously it is the extent of the causal link which is at issue. Judge Bishop recognised this. At par 29 of his judgment he held that the meaning to be adopted was that "substantial" meant "more than minimal, large or great". In my view this was the correct approach, remembering that word is used in a relative sense, recognising that other causative factors may be present. Section 9A does not require that the employment must be "the" substantial contributing cause, nor does it attempt to exclude predisposition or susceptibility to a particular condition (cf University of Tasmania v Cane (1994) 4 Tas R 156).
28 This interpretation of "substantial" accords with the Attorney General's Second Reading speech set out above (par 12).
29 The appellant submits that whether or not the activity causing injury can occur outside the workplace is an irrelevant consideration. I disagree. Section 9A(2) requires the Court to take into account the probability that the injury or a similar injury would have happened anyway, at about the same time or at the same stage of the worker's life, if he or she had not been at work or had not worked in that employment (par (d)).
30 The appellant also submits that the trial judge erred in failing to take into account a relevant consideration, namely the lack of symptoms in the knee for 20 years before the injury. There is no merit in this proposition. The injury is referred to. Its possible capacity to predispose the worker to risk of further injury was not overlooked.
A substantial contributing factor is not equivalent to an injury arising out of employment
31 As indicated above, it was relevant for his Honour to have recorded (par 8, above) that the precise activity that led to the appellant's workplace injury was a type of activity that could have occurred elsewhere, for example at home. This type of information is required to be taken into account by s9A(2)(d). However, nothing in s9A makes this determinative. The continuing presence of the words "arising out of or in the course of employment" in the definition of "injury" means that it is not essential that the worker prove that employment created any "special danger" (contrast Thom v Sinclair [1917] AC 127 at 142, Craske v Wigan [1909] 2 KB 635 at 637), "employment risk" or "added peril" (Plumb v Cobden Flour Mills Co Ltd [1914] AC 62 at 68). Accordingly, I respectfully disagree with the reasoning of Burke CCJ in Dayton (at [111]-[116]) which drew upon these English cases.
32 In the present case Bishop CCJ held (at [31]) that the addition of the word "substantial" to "contributing factor" in s9A, combined with the provisions in subs (3), led to the conclusion that "a substantial contributing factor" is as stringent a concept as that of "arising out of" the employment, if not more so. I do not agree. The requirement that employment be a contributing factor to the "injury" is not equivalent to the expression "arising out of the employment". It is not easy to apply a causation requirement to a provision which continues to define "injury" as including injury arising in the course of employment. However, work has to be found for all of the words used, unless this proves an impossible task. Section 9A(3)(a) does not preclude this, because it goes no further than deeming employment not to be a substantial contributing factor to an injury "merely because" the injury arose in the course of the worker's employment etc.
33 This, in effect, was the view taken by Ashley J of the Supreme Court of Victoria in Popovski v Ericsson Australia Pty Ltd [1998] VSC 61 in construing s82(1) of the Accident Compensation Act 1985 (Vic), which gives a right of compensation to a worker caused "an injury arising out of or in the course of any employment and if the worker's employment was a significant contributing factor" . His Honour said:
[51] I turn to the precise question which was determined in Favelle Mort v Murray - the meaning of the definition of "injury" in the legislation there under consideration. Barwick CJ, Stephen and Mason JJ all said that the requirement suggested by the words "to which the employment was a contributing factor" was less stringent than was suggested by the concept "arising out of" an employment. Mason J made the point that there was every reason for giving different words a different meaning. How do these conclusions bear, if at all, upon the words "to which the employment was a significant contributing factor"?
[52] In my opinion the following propositions may be stated: first, the present language by intention and effect requires a more substantial causal link between employment and injury than did the language considered by the High Court in Favelle Mort v Murray .
[53] Second, there remains a distinction between the concepts of injury "to which the employment was a significant contributing factor" and injury "arising out of" employment. What Mason J said in Favelle Mort v Murray about the use of different language holds good.
[54] Third, the requirement that injury "arise out of" employment remains more stringent than the requirement that employment be "a significant contributing factor" to injury. It is possible to envisage situations in which injury might not satisfy the former test yet would satisfy the latter test. It might be the case, to take an example, that a man struck directly by a bolt of lightning at his work place would not (consonant with the old authorities) suffer injury arising out of his employment; but that his employment - regardless that his duties did not require him to be at the critical place at the critical time - would, be a significant contributing factor to his injury.