Workers Rehabilitation and Compensation Act 1988, ss 3(1), 3(2A), 25.

St Helens Oysters Pty Ltd v Coatsworth [2007] TASSC 90, 17 Tas R 4, applied

Long v Kmart Australia Ltd [2016] TASSC 6, 25 Tas R 237, referred to.

Judgment Number: [2020] TASFC 2

1. This appeal involves the application of s 3 of the Workers Rehabilitation and Compensation Act 1988 (the Act), in the context of the respondent's referral of the appellant's claim for compensation for a determination by the Workers Rehabilitation and Compensation Tribunal (the Tribunal), under s 81A of the Act. After a hearing pursuant to that section, the Tribunal ordered that compensation not be paid and the appellant appealed to this Court against that determination.
2. The question arising is whether it is "reasonably arguable", on the evidence that was before the Tribunal, that the appellant's employment was not the major or most significant factor contributing to a "recurrence, aggravation, acceleration, exacerbation or deterioration" of his pre-existing lumbar spondylosis, for the reason that a natural degenerative process is open as an alternative explanation.
3. The learned primary judge, Brett J, held that, for the purposes of s 81A, the evidence left open a reasonable argument that, following a contested final hearing, the appellant's claim might be rejected, having regard to the requirement that the appellant's employment must be shown to be the major or most significant factor in the aggravation or exacerbation of the underlying disease.
4. The learned primary judge concluded that the only medical reports in evidence, prepared by neurosurgeon, Mr Peter Dohrmann, were so worded that, on one interpretation of them, it could be inferred that he was expressing a view that would result in the injury being compensable, that is that employment was the major or most significant contributing factor, but that it was also open to conclude that Mr Dohrmann would not attribute that high level of contribution to the appellant's employment, notwithstanding that it was "a" major contributing factor. His Honour found that it was implicit in Mr Dohrmann's opinion as to the nature of the appellant's underlying disease, that natural progression may also have played a role in the onset of the appellant's symptoms on the date of his claimed injury.
5. The appeal to this Court was argued on five grounds. The gravamen of those grounds, as I understand them, is that the test posited by s 3(2A) of the Act, on an application to the Tribunal under s 81A, is a "comparative" test such that it was permissible to characterise the appellant's employment as "the major or most significant factor" if no other major causative factor was identified on the material presented on the application.
6. In symbiosis with that argument other grounds of appeal assert that there was no other cause that could, on the material presented at the s 81A hearing (and not that which might be presented at a later hearing), have reasonably displaced the appellant's employment as the major or most significant contributing factor. The notice of appeal also asserts that the learned primary judge erred in his finding that the evidence disclosed an "implicit" view that natural progression may also have also played a role in the onset of the appellant's symptoms. A further ground of appeal asserts that "no reasonable tribunal could have made that finding on the material presented".
7. For the reasons that follow, I am of the view that the learned primary judge did not err, that there is no merit in the appeal, and that it should be dismissed.

1. The liability of an employer to pay compensation arises by virtue of s 25(1) of the Act. That section provides as follows:

"25 Liability of employers to compensate workers for injuries

(a) a worker suffers an injury, not being a disease, arising out of or in the course of his employment; or

(b) a worker suffers an injury, which is a disease and to which his employment contributed to a substantial degree, within the meaning of section 3(2A) -

his employer is, except as is otherwise provided by this Act, liable to pay compensation in accordance with this Act -

1. Section 3 of the Act contains the following definitions:

"disease means any ailment, disorder, defect, or morbid condition, whether of sudden or gradual development;

(b) the recurrence, aggravation, acceleration, exacerbation or deterioration of any pre-existing injury or disease where the employment was the major or most significant contributing factor to that recurrence, aggravation, acceleration, exacerbation or deterioration - "

1. Section 3(2A) provides:

"(2A) For the purposes of this Act, employment contributed to a disease to a substantial degree only if it is the major or most significant factor."

1. The juxtaposition of the extended definition of the term "injury" in ss 3 and 3(2A) was explained by the learned primary judge at [58] of his reasons as follows:

"58 As has already been noted, the requisite causal relationship is that the appellant's employment was the major or most significant contributing factor to the aggravation or exacerbation. The use of the definite article in this legislative formulation is important. Section 3(2A) was introduced by an amendment in 1995 (16/1995) in response to the decision of the Full Court in University of Tasmania v Cane [1994] TASSC 73; (1994) 4 Tas R 156. That case had dealt with the previous formulation of s 25(1)(b), which provided that compensation was payable to a worker who 'suffers an injury, which is a disease, arising out of and in the course of his employment and to which his employment has contributed to a substantial degree'. The extended definition of injury had not then been inserted into the Act. The effect of that decision was that the required causal contribution of the employment to the disease must be 'substantial' which was to be assessed in a relative sense and required only that the work related cause be 'more than trivial or inconsequential'. This formulation of the test was applied by Zeeman J in Attorney-General v Smith [1994] TASSC 138. In the second reading speech of the Bill which inserted s 3(2A), the Minister, Mr Groom, made it abundantly clear that the amendment was in response to this judicial interpretation and that the intention was to establish the requirement for the employment to be the principal contributing factor to the disease. The provision was further amended by No 99 of 2000, by inserting the word 'only' before the words 'if it is the major or most significant factor', thereby establishing without doubt the necessity for employment to be the predominant contributing factor to the disease, or the aggravation or exacerbation of the disease, if the injury is to fall within s 25(1)."

1. The nature of a s 81A referral to the Tribunal was explained by the learned primary judge at [5]-[7] of his reasons as follows:

"5 The scheme implemented by s 81A is that an employer who disputes liability in respect of a claim for compensation, must serve a notice of dispute on the worker, which informs the worker of the reasons for the dispute, and must then refer the matter to the Tribunal. The employer must do this within 84 days of receiving the claim. If this is not done within that time, the employer will be taken to have accepted liability in respect of the claim (s 81AB). Upon referral, the Tribunal must order the employer to make the specified payments unless it considers that 'a reasonably arguable case exists concerning the liability of the employer to pay compensation', in which case it shall determine that compensation is not to be paid by the employer. The Act therefore establishes 'a relatively speedy process for assessing whether an employer, who wishes to dispute liability to pay weekly compensation, has a reasonably arguable case in that regard ...' (per Crawford J (as he then was) in Walker v J and A Freeman Building Services [2006] TASSC 90, 16 Tas R 87). This process is consistent with the beneficial nature of the legislation.

6 It is well established that the employer bears the onus of demonstrating the existence of a reasonably arguable case that compensation is not payable: Skill Group Limited v Anning [2015] TASSC 18, 23 Tas R 463; Lamont v M R V Supermarkets Pty Ltd [2016] TASSC 16, 24 Tas R 234. The section requires the employer to compile and deliver evidentiary material: s 81A(2)(b). The test to be applied by the Tribunal on the referral has been described in the following terms:

'a reasonably arguable case will exist concerning the liability of an employer to pay a worker if it is reasonably arguable on the material available in relation to the claim or identified deficiencies or weaknesses in the claim that, following a contested hearing it may be rejected.'

St Helens Oysters Pty Ltd v Coatsworth [2007] TASSC 90, 17 Tas R 43.

7 It is not sufficient for the employer to indicate that it simply wishes to put the worker to proof: Vos Construction & Joinery Pty Ltd v Norton-Smith [2016] TASSC 38, per Pearce J at [5]."

1. It is well established that the test to be applied in the appellant's case, by the Tribunal, and now by this Court, is whether on the evidence available in relation to the claim at the time of the s 81A referral a reasonably arguable case exists concerning the liability of the employer to pay compensation.
2. In St Helens Oysters Pty Ltd v Coatsworth (above) at [10], Evans J explained what was meant by the term "a reasonably arguable case":

"10 The phrase 'a reasonably arguable case' was introduced into s 81A in substitution for the phrase 'a genuine dispute' by the Workers Rehabilitation and Compensation Amendment (Miscellaneous) Act 2004, s 24. The test embodied by the latter phrase had been construed as embodying a subjective element, that is, whether the employer's rejection of liability was genuine; Haas Investments Pty Ltd v Viney [2001] TASSC 147, par 10 and State of Tasmania v Gregson [2002] TASSC 76, pars 5 and 6. By substituting a test that involves reasonableness for a test that involved genuineness, the amending legislation removed that subjective element from the test and replaced it with an objective element. Whilst the focus of the objective element is on the arguability of the case, that focus inevitably extends to the case itself. A case will not be reasonably arguable unless the case itself is reasonable in the sense that there is a reasonable prospect of the claim being rejected following a final hearing. By the same amending legislation, the period prescribed by s 81A(1) within which an employer may dispute a worker's claim was increased from 28 days to 84 days. This increase recognises the added burden placed on an employer by the introduction of the new test. Employers have been allowed more time within which to investigate a worker's claim and, in the event that it is disputed:

• formulate the reasons for disputing the claim and inform the worker of the same, s 81A(1)(b); and
• compile and deliver any evidential material upon which the employer intends to rely on the hearing of the matter, s 81A(2)(b).

These amendments have no bearing on the nature of the determination to be made. It is a preliminary determination that results in interim orders. The very notion of a 'reasonably arguable case' like the very notion of a 'prima facie case', precludes a final determination of a disputed question of fact. See North Ganalanja (supra) at 639. On the face of s 81A, a reasonably arguable case will exist concerning the liability of an employer to pay a worker if it is reasonably arguable on the material available in relation to the claim or identified deficiencies or weaknesses in the claim that, following a contested hearing it may be rejected." (Italics added.)

1. It is clear that the relevant assessment must be carried out on the basis of the evidence available at the time of the referral and not on the basis of additional evidence that might be adduced on a final hearing, which might establish another possible cause as the major or most significant factor. However, that does not mean that the contested nature of a final hearing and the inevitable testing on that hearing of the evidence available at the time of the referral, must be ignored.
2. Thus, the question in the present case is, in my view, exactly as the learned primary judge put it at [49] of his reasons, namely, "whether the evidence permitted a reasonable argument that the appellant's employment was not the major or most significant factor in the causation of the aggravation or exacerbation of the underlying disease". Or, put another way, whether Mr Dohrmann's presently available evidence might reasonably be argued as establishing that the major or most significant contributing factor could not be said to be the appellant's employment because it was not possible to determine what role his employment actually played in the exacerbation of his congenital spondylosis, as opposed to other factors, including the natural progression of the degenerative changes in his spine.
3. Whilst the employer carries the onus of proof on a s 81A application, I accept the submission put on behalf of the respondent by his counsel, Mr Jackson SC, in his written submissions, that what the employer is required to prove is not that there is no liability under s 25 of the Act, but only that there exists, on the evidentiary material the employer relies upon in the s 81A proceedings, a reasonable chance that the worker will be unable to discharge the onus of proof that will ultimately rest with the worker by virtue of the Act, s 49(2)(a), on a final hearing of the worker's claim. As Mr Jackson put it, "the employer was certainly not required in this instance to positively prove that some specific factor other than the worker's employment was the major or most significant contributing factor".

1. As the learned primary judge noted at [47] of his reasons, the only reasonable conclusion available from the evidence before the Tribunal was that the appellant's incapacity arose from an aggravation or exacerbation of his underlying lumbar degenerative disease and that was an injury within the relevant definition. However, liability on the part of the respondent to pay compensation for that injury depended on the existence of the requisite causal relationship between the employment and the injury.
2. The causal requirement relates to the aggravation or exacerbation of the underlying disease and not to the development of the disease itself. In the case of an aggravation, or exacerbation of a pre-existing disease, the injury will fall within s 25(1)(b) of the Act if the employment was the major or most significant contributing factor to that aggravation or exacerbation.
3. Mr Dohrmann does not expressly state that such was the case with the appellant. His opinion as encapsulated in his first report, dated 4 July 2018 is in the following terms:

"Noting the definition in the Tasmanian legislation, I consider that Mr Bradshaw has suffered an injury in this context. I think that the injury needs to be seen in the context of his employment over 35 years and noting the inherent requirements of the role, I further note that Mr Bradshaw has used a reach fork for the past eight years and has described daily activities which include regular twisting motions of the trunk. It is in this respect that I believe that a reasonable argument can be made that his employment has been a major contributing factor to the aggravation of lumbar spondylosis from which he now suffers.

While it is realised that Mr Bradshaw did not suffer any specific incident on 04.05.2018, in that he was simply walking a couple of steps when he experienced back pain, I think that the work-related causation of his current lower back condition needs to be seen in a much longer context." (Italics added.)

1. In his second report dated 23 July 2018 Mr Dohrmann said, relevantly, as follows, in response to some questions posed to him in a letter from the respondent's solicitors:

"In respect to point 3, I would accept that Mr Bradshaw did not suffer a traumatic incident on 04.05.2018. However, I consider that the acute symptoms he experienced on that day, while spontaneous in onset, were due to pre-existing lumbar spondylosis to which employment over a long period of time has made some contribution.

... it is reasonable to conclude that there was no specific incident or accident, and therefore no particular event or activity, that caused injury on 04.05.2018.

In respect of point 11 on page 3 of your letter, it remains my view that Mr Bradshaw was suffering from lumbar spondylosis, where his employment has contributed to the acceleration of that condition by way of aggravation over many years, and perhaps more specifically over the past eight years or thereabouts, during which time I understand he has been regularly using a reach forklift. He was therefore suffering from a work-related condition on 04.05.2018, but this was the same condition that he was suffering from prior to that date. I can confirm that Mr Bradshaw appears not to have suffered a specific work-related injury on 04.05.2018." (Italics added.)

1. To my mind Mr Dohrmann is offering a combined legal and medical opinion which may well be based on a misunderstanding of the relevant focus of the legally required factual causation. That is to say, the long-time aggravation of the underlying disease and not the exacerbation of symptoms on 4 May 2018. However, and in any event, at its highest Mr Dohrmann does not state that the appellant's employment was "the major or most significant" contributing factor to the exacerbation he suffered specifically on 4 May 2018. He did not use those words. I reject the appellant's submission that those words are merely such that "there is no need for the formula to be recited in the relevant opinion on a ritualistic basis". The relevant opinion must establish the required level of contribution. It does not, either semantically or implicitly. Mr Dohrmann's opinion was sophisticated. I would infer that had he felt able to state clearly that there was the statutorily required level of contribution, then he would have done so.
2. The appellant argues that nowhere in his reports does Mr Dohrmann suggest that the natural progression of the appellant's disease could be a more significant contributor to the aggravation than his employment. To my mind however, it was not necessary for him to have done so in order for the learned primary judge to have reached the view that he did. The evidence demonstrated that the disease is a progressive disease.
3. Mr Dohrmann's statement in his first report was, "Mr Bradshaw has used a reach fork for the past eight years and has described daily activities which include regular twisting motions of the trunk. It is in this respect that I believe that a reasonable argument can be made that his employment has been a major contributing factor to the aggravation of lumbar spondylosis from which he now suffers". (Italics added.) That statement does not, on any view, whether taken alone or in the context of all of Mr Dohrmann's other statements, render it not reasonably arguable that the appellant's symptoms on 4 May 2018 were as a result of the natural progression of his pre-existing disease. Indeed, the accepted absence of any "specific incident" on that day renders the contribution of such progression well arguable in my view.
4. Mr Dohrmann's statement in his second report that "the acute symptoms [the appellant] experienced on that day, while spontaneous in onset, were due to pre-existing lumbar spondylosis to which employment over a long period of time has made some contribution", does not meet the required standard of contribution either. Moreover, the use of the words "some", on two occasions in that report, renders it well arguable in my view that the major or most significant contribution was some other factor, including the natural progression of the appellant's underlying disease. (Italics added.)
5. Notwithstanding that he was not cross-examined on the hearing of the s 81A application, on a final hearing Mr Dohrmann's statements might be explained more clearly through examination of him in oral evidence. However, as I apprehend it, his views, as presently expressed, fall well short of establishing that the appellant's employment was the major or most significant contributing factor to the onset of his symptoms on 4 May 2018. Mr Dohrmann's words, whatever he may have intended them to mean, leave it reasonably arguable, in my view, that it cannot be determined precisely what role the appellant's employment played in the occurrence of those symptoms.
6. In those circumstances the referral in St Helens Oysters Pty Ltd v Coatsworth (above) is instructive. In that case two grounds were raised concerning the liability of the employer for the worker's claim. Firstly, that the worker's disease did not arise out of his employment, and that if it did, then his employment did not contribute to it to a substantial degree, that is, it was not a major or significant factor in the disease, it being attributable to the failure of the company in which the worker and his wife (through their family trust), held a 50% share. Secondly, that if the first ground failed then, in any event, compensation was not payable as the disease arose substantially from the termination of the worker's employment, which was a reasonable administrative action taken in a reasonable manner by his employer in connection with the worker's employment. The reasoning of Evans J at [14], is apposite to the present case. His Honour there said:

"... it was not possible to determine what role the worker's employment played in his disease. Of necessity this means that it was not possible to determine whether such role as his employment played arose substantially from its termination. In these circumstances, on the limited material before the learned Commissioner, there was a reasonably arguable case that the employer could rely on s 25(1A)(c) to avoid liability to the worker." (Italics added.)

1. I accept the submission made by Mr Jackson, that the passage set out above from the judgment of Evans J "can be instructively paraphrased by reference to the facts of this case in answer to this ground, and indeed to the appeal as a whole." That is to say:

"... on the limited information before the learned Commissioner, it was not possible to determine what role, if any, the worker's employment played in the aggravation or exacerbation of his pre-existing disease. Of necessity this means that it is not possible to determine whether such role as his employment played necessarily excludes a reasonable argument that employment is not 'the major or most significant' contributing factor. In these circumstances, on the limited material before the learned Commissioner, there was a reasonably arguable case that the worker will not be able to discharge the onus of proving causation to the required degree."

1. I reject the appellant's submission that it is "plain" from the whole of Mr Dohrmann's evidence that he considered that the appellant's employment was "the major or most significant contributor to the aggravation". And the contrary only needs to be reasonably arguable for the respondent to succeed on the s 81A application. The Act does not require that the respondent's case about liability be "strong or compelling", but only that "the case that the claim may ultimately be rejected must be reasonably arguable" (Voss Construction & Joinery P/L v Norton Smith [2016] TASSC 38, 26 Tas R 448 at [5]).

1. In my opinion the evidence presented at the hearing of the s 81A application permitted a reasonable argument that the appellant's employment was not the major or most significant factor in the causation of the aggravation or exacerbation of his underlying disease occurring on the day in question. While there may be a "comparative test" to be imported into the relevant provisions of the Act, there is no requirement that the employer must, in s 81A proceedings, be able to point to evidence of something other than a worker's employment as being a more significant causative factor. As was submitted by counsel for the respondent in his written submissions, the test for causation ultimately requires that employment is identified "as the superlative contributory factor, that is, the factor that surpasses all other contributing factors, not merely identification of employment as one of any number of major or significant factors".
2. I do not accept the final submission made on behalf of the appellant in his written submissions, namely, that on the hearing of the s 81A application:

"To establish a reasonably arguable case in the circumstances of this case Dr Dohrmann's evidence would have to be capable of proving that the natural progression of the disease was causative of the symptomology of the aggravation suffered by the appellant and capable of being found to be more major or more significant than the major causative factor specifically identified and specifically said by Mr Dohrmann."

1. It is enough if Dr Dohrmann's evidence was insufficient to exclude a reasonable argument that the appellant's employment was not the major or most significant contributor to the exacerbation on 4 May 2018.
2. Finally, it follows from all that I have said, that I reject as untenable the ground of appeal which asserts that no reasonable tribunal could have made the finding on the material presented, that it was implicit in Mr Dohrmann's view that natural progression of his pre-existing disease may have played a role in the onset of the appellant's symptoms on 4 May 2018. If the other grounds of appeal fail, as I find they should, then so too should that ground.
3. I would dismiss the appeal.

1. I agree the appeal should be dismissed for the reasons given by Estcourt J and Porter AJ.

1. On 4 May 2018, in the course of his employment with the respondent, the appellant suffered an onset of severe low back pain and was incapacitated. The respondent disputed its liability to pay workers' compensation and, under s 81A of the Workers Rehabilitation and Compensation Act 1988 (the Act), referred the matter to the Workers Rehabilitation and Compensation Tribunal.
2. A Commissioner determined that a reasonably arguable case existed concerning the respondent's liability, and directed that payments not be made. The appellant appealed. Brett J held that the Commissioner had erred in law but, in determining the matter for himself, reached the same conclusion and dismissed the appeal: [2019] TASSC 41. The appellant appeals to this Court.
3. I have read the reasons for judgment of Estcourt J. I agree with what his Honour has said about the nature of a referral under s 81A of the Act and the test to be applied. For the reasons that follow, I also agree that the primary judge did not make any error, and that the appeal should be dismissed.

1. The material the respondent put before the Tribunal largely consisted of two reports from a neurosurgeon, Mr Peter Dohrmann, dated 4 July 2018 and 23 July 2018. The appellant was seen by Mr Dohrmann at the respondent's request. The second report was prepared in response to a discussion between Mr Dohrmann and the employer's solicitor on 17 July, and a 'follow up' letter from the solicitor to Mr Dohrmann dated 18 July. I will come back to the detail of these documents.
2. The worker's case for payments of compensation has been and is advanced on the following factual basis. These points are taken from Mr Dohrmann's first report, and are accepted by the appellant.
   • As at May 2018, the appellant had been employed by the respondent as a storeman for 35 years, and for the past eight years had been using a "reach fork" for 90% of his daily tasks.
   • Use of the reach fork involved repeated head movements and twisting movements of the trunk to right and left, as well as looking upwards.
   • In 2016, following the gradual onset of intermittent episodes of severe low back pain, the appellant underwent lower back surgery with an apparently good result leaving him with numbness of the left heel.
   • In May 2017 the appellant developed left sciatica which gave rise to conservative treatment.
   • On 18 April 2018 the appellant underwent a nerve block procedure for left sided symptoms.
   • In the days before 4 May 2018, the appellant suffered no low back pain but was suffering "a little right sciatica".
   • On 4 May 2018 after using the reach fork, he alighted from it, took two steps and then developed severe right sided low back pain which caused him to double up on the floor.
   • The appellant had to go home and has been unable to work since that date. He has received treatment but suffers from persisting right sided low back pain.
   • As at 4 May 2018, the appellant had pre-existing significant lumbar spondylosis.
3. I pause to observe that in the proceedings before the Tribunal, no direct evidence or explanation was given about what lumbar spondylosis is, or its nature and consequences. The Commissioner was obliged to resolve the matter on such evidence as was placed before her: s 57 of the Act. However, there is some mention in Mr Dohrmann's reports about what the condition might involve and, as I understand it, the appellant does not dispute the proposition that, in broad terms, lumbar spondylosis is a progressive degenerative disease. The appeal concerns the state of the evidence before the Tribunal about its progression, the stage it had reached on 4 May, and what role it played in the onset of pain on that day.
4. The appellant's case has been and is advanced on the basis that the appellant suffered an "injury" within the meaning of par (b) of the definition of "injury" in s 3(1) of the Act. By that definition, an injury is said to include:

"(b) the recurrence, aggravation, acceleration, exacerbation or deterioration of any pre-existing injury or disease where the employment was the major or most significant contributing factor to that recurrence, aggravation, acceleration, exacerbation or deterioration - ...".

1. Section 25 of the Act sets out the circumstances in which an employer will be liable to pay compensation. Relevantly, the section provides as follows:

"25 Liability of employers to compensate workers for injuries

(a) a worker suffers an injury, not being a disease, arising out of or in the course of his employment; or

(b) a worker suffers an injury, which is a disease and to which his employment contributed to a substantial degree, within the meaning of section 3(2A) -

his employer is, except as is otherwise provided by this Act, liable to pay compensation in accordance with this Act -...".

1. Section 3(2A), referred to in s 25(1)(b), provides that employment contributed to a disease to a substantial degree only if it is the major or most significant factor.
2. Except where specific reference is required, it is convenient - as senior counsel for the appellant did - to collectively refer to the five substantive words in the par (b) definition as 'aggravation'. Because s 25 is the sole source of foundational liability to pay compensation, and because a par (b) "injury" is not separately dealt with in that section, it means that such an injury has to fit within s 25(1)(a) or (b). When dealing with a par (b) injury that fits within s 25(1)(b), the requirement that the employment be the major or most significant contributing factor is duplicated by reason of the definition in s 3(2A) of contribution to a substantial degree. In Long v Kmart Australia Ltd [2016] TASSC 6, 25 Tas R 237 at [52], I pointed out the "significant linguistic contortions" that are involved in that situation. It is quite clear though, that it is the aggravation to which the employment must be the major or most significant contributing factor.

1. The respondent's referral is dated 24 July 2018. It says:

"A dispute is sought [sic] on the following basis:

(i) That it is reasonably arguable that the worker did not suffer an injury which arose out of or in the course of his employment in accordance with Section 25(1)(a) of the Act

(ii) That it is reasonably arguable that the worker did not suffer an injury which was a disease to which his employment was a substantial contributing factor in accordance with Section 25(1)(b) of the Act

(iii) As part of Section 25(1)(b), nor did the worker suffer an injury in accordance with the extended definition set down in Section 3 of the Act."

1. As can be seen, the respondent covered all the avenues available under the Act, although in subpar (iii) it seemed to confine consideration of the par (b) definition of injury to pre-existing disease.
2. In Mr Dohrmann's first report of 4 July 2018 he said he considered the appellant was suffering from an aggravation of lumbar spondylosis. In answering a question about whether the appellant had suffered an injury or "sustained" a disease on 4 May 2018, Mr Dohrmann said he had suffered an injury in the form of an aggravation of pre-existing lumbar spondylosis which occurred in the course of his employment on 4 May 2018. In responding to a request for comment on whether the appellant had sustained an injury within the meaning of the par (b) definition, Mr Dohrmann said he considered the appellant had suffered an injury in that context, and went on to say:

"I think that the injury needs to be seen in the context of his employment over 35 years and to noting the inherent requirements of the role. I further note that Mr Bradshaw has used a reach fork for the past eight years and has described daily activities which include regular twisting motions of the trunk. It is in this respect that I believe that a reasonable argument can be made that his employment has been a major contributing factor to the aggravation of lumbar spondylosis from which he now suffers."

1. Further, in the first report Mr Dohrmann said that while it is realised that the appellant did not suffer any specific incident on 4 May 2018, he thought "the work-related causation of his current lower back condition needs to be seen in a much longer context". In the second report, Mr Dohrmann said he considered that the acute symptoms on 4 May, while spontaneous in onset, were due to pre-existing lumbar spondylosis "to which employment over a long period of time has made some contribution".
2. The letter of the employer's solicitor to which I have referred is dated 18 July 2018. Part of it refers to a discussion with Mr Dohrmann about the issue of causation. In point 8 of that part, Mr Dohrmann is asked whether he agrees with the proposition that there was no further insult or process (assuming an underlying state of vulnerability to injury) that was contributed to by work to a substantial degree on 4 May. In response, Mr Dohrmann agreed that there appears not to have been any additional insult or process on 4 May "that could be identified as having contributed to any pre-existing (at least partially work-related) lumbar degenerative condition."
3. Point 9 of the letter is in the following terms:

"I also asked you whether there was any evidence of any pathological change occurring on 4 May 2018 and indeed whether Mr Bradshaw's condition was a natural progression of an underlying disease where work was merely the occasion for noticing symptoms rather than the cause of any pathological change. You agreed with that proposition. Can you please confirm that is your view?" [Original emphasis.]

1. Mr Dohrmann confirmed in respect of point 9, "that it was not possible to identify any specific pathological change that occurred on 04.05.2018, though there was clearly a significant increase in symptoms from that date". He continued:

"[I]t remains my view that Mr Bradshaw was suffering from lumbar spondylosis, where his employment has contributed to the acceleration of that condition by way of aggravation over many years, and perhaps more specifically over the past eight years or thereabouts, during which time I understand he has been regularly using a reach forklift. He was therefore suffering from a work related condition on 04.05.2018, but this was the same condition that he was suffering from prior to that date."

1. In the hearing before the Tribunal, then counsel for the respondent took the Commissioner through the reports, submitting that the terms of the referral were "a fair reading of this correspondence". In a series of discursive submissions, counsel submitted that there was no injury simpliciter within the meaning of s 25(1)(a) of the Act, nor any further insult or process that contributed to the worker's condition to a substantial degree on 4 May; there was no evidence of pathological change, with "no evidence that any of the activities [performed] on 4 May represented ... a specific injury, I suppose in particular, going to the issue concerning aggravation or whatever". He added that Mr Dohrmann did talk about the possibility of aggravations over many years but (Mr Dohrmann) seemed to put it on the basis that the appellant may have been suffering from a work-related condition that existed before 4 May, but 4 May was not "something new, isn't an injury, whatever the situation might have been in 2014 to 2016".
2. Then counsel for the appellant made it plain that what was being relied on was the extended definition of injury under s 3; that is, a par (b) injury. She noted Mr Dohrmann's statement that the appellant had suffered an injury in that context; that is, an aggravation of pre-existing lumbar spondylosis. She also noted Mr Dohrmann's view that the appellant's employment contributed to the acceleration of the spondylosis, submitting that Mr Dohrmann supports the appellant's case that he suffered a work-related injury by way of the extended definition.
3. In holding that there existed a reasonably arguable case, the Commissioner said that it appeared to be incontrovertible that there may well have been an underlying condition to which the employment may have contributed over many, many years, the claim itself is for an incident or injury occurring on 4 May 2018. " ... I accept [the respondent's] submissions that a fair reading of Mr Dohrmann's opinion as contained in the totality of his two reports is enough for there to be an arguable case that nothing satisfying the definition of injury within the Act happened on that date."
4. It is in that context that the appellant appealed.

1. The primary judge, after discussing the evidence and the bases upon which liability might be established under the Act, said that, at the very least, the natural degenerative process must be open as an alternative explanation: [41]. His Honour went on to say that the only reasonable conclusion available on the evidence was that the symptoms on 4 May were an aggravation of the underlying degenerative condition: [43]. Later, at [47], his Honour said the only reasonable conclusion available was that the appellant's incapacity arose from an aggravation or exacerbation of the underlying disease; that was an injury within the relevant definition, but liability to pay compensation for that injury depended on the existence of the requisite causal relationship between the employment and the injury. At [48], he noted that the causative requirement relates to the aggravation or exacerbation of the underlying disease, not the development of the disease itself.
2. His Honour continued:

"[49] Accordingly, the question for the Commissioner was whether the evidence permitted a reasonable argument that the appellant's employment was not the major or most significant factor in the causation of the aggravation or exacerbation of the underlying disease. In the circumstances of this case, that question really came down to whether the evidence permitted a reasonable argument that there were other possible causes of the appellant's pain as he experienced it on 4 May, other than his employment, which might qualify as the major or most significant factor.

[50] It is apparent from the Commissioner's brief reasons that she did consider this question, but confined that consideration to whether the aggravation or exacerbation had arisen because of work related circumstances, such as a specific incident, insult or process which had taken place on 4 May. In doing so, she accepted the respondent's counsel's argument that the question was so confined. I am satisfied that in restricting her consideration of the requisite causal link in this way, the learned Commissioner was in error.

[51] There is little doubt that it was arguable that the symptoms did not arise from a specific incident or insult on 4 May. The effect of Mr Dohrmann's second report was that it was not possible to identify a specific incident or additional insult or process, or specific pathological change on 4 May 2018, as the cause of the symptoms which had led to incapacity on that day. However, none of those circumstances was an essential prerequisite to the respondent's liability to pay compensation. A temporal connection between employment and the underlying process which led to the increase in symptoms on 4 May was not necessary. As Porter J said in Long v Kmart Australia (above) at [78]:

'The test does not require an "aggravation" to occur, commence or conclude in the course of the employment. The question is simply whether there has been an "aggravation" of a pre-existing disease, and whether the employment has the requisite degree of causal connection.'

[52] The Commissioner misstated and misapplied this test. It is clear from her brief reasons that she was looking for events on 4 May which had both a causal and temporal connection with the aggravation or recurrence. This was not necessary. The Commissioner's misunderstanding of the legislative test is a classic error of law."

1. The primary judge said the error necessarily invalidated the determination of the existence of a reasonably arguable case. Noting that the material before the Tribunal was the same documentation as was before the Court, his Honour determined the issue for himself. He declared he was satisfied that a reasonably arguable case existed concerning the liability of the respondent to pay compensation, adding that had the Commissioner correctly determined and applied the law, she would inevitably have reached the same conclusion.
2. In making his finding, the primary judge said that the use of the definite article in the legislative formulation "the major or most significant factor" is important. After noting Mr Dohrmann's use of the indefinite article in the critical passage of the first report (set out above), the primary judge said a finding that the employment was a major contributing factor to the aggravation would not be sufficient to make the injury compensable. [My emphasis.] His Honour considered what was involved in a determination under s 81A, and continued:

"[63] In this case, although Mr Dohrmann expresses the opinion that employment was causally related to the development of the disease, he does not directly and squarely deal with the question of whether it is 'the major or most significant contributing factor' in respect of the aggravation or exacerbation experienced by the appellant on 4 May. On one interpretation of his reports, it can be inferred that he was expressing a view that would result in the injury being compensable, that is that employment was the major or most significant factor. However, in my view, it is also open to conclude that he would not attribute to the employment this level of contribution, notwithstanding that it was a major contributing factor. It is implicit in his opinion as to the nature of the underlying disease that natural progression may also have played a role in the onset of symptoms on 4 May. This may well explain his choice of words. ...".

1. The essential question is whether, on the evidence, it was reasonably arguable that the respondent was not liable for weekly payments or other benefits. The issue is one of foundational liability with causation the sole focus. In this appeal, the appellant does not argue that the primary judge made any error as to the construction and application of the provisions of the Act that relate to a par (b) injury. However, because of the wording of Mr Dohrmann's reports and the submissions made, I think it might pay to summarise the operation of those provisions, and in that light examine the way in which the appellant's claim is put.
2. In summarising the operation of the extended definition, I rely on observations made in Long v Kmart Australia (above) at [24], [43]-[52], [67] and [78], most of which were quoted or referred to by the primary judge. In turn, those observations were derived from statements in Federal Broom Co Pty Ltd v Semlitch [1964] HCA 34; (1964) 110 CLR 626, Darling Island Stevedoring & Lighterage Co Ltd v Hankinson [1967] HCA 10; (1967) 117 CLR 19, University of Tasmania v Cane [1994] TASSC 73; (1994) 4 Tas R 156 and Cook v Midpart Pty Ltd t/as McDonalds Forster [2008] NSWCA 151.
3. The par (b) injury definition applies irrespective of how the pre-existing condition was caused or contracted. As to a pre-existing disease, as the primary judge noted at [48], the causative requirement relates to the aggravation or exacerbation of the underlying disease, not the development of the disease itself. The provision operates so that, for instance, an aggravated non-work related pre-existing condition becomes an 'injury' within the meaning of the Act. In the case of the acceleration of a disease, it is the acceleration of the disease which becomes the 'injury', not the accelerated disease.
4. The substantive words used in par (b) are not to be treated as synonymous. While there may be some overlap, they have different shades of meaning and connote different outcomes. It should be borne in mind that they do describe outcomes or consequences upon pre-existing conditions. The essence of the operation of the provision is that, irrespective of whether existing pathology has been advanced or worsened, there is 'aggravation' if the symptoms and difficulties emanating from it have increased or become more serious.
5. As to the words themselves, "aggravation" as such might be more readily applied in the case of a pre-existing injury. "Exacerbation" might overlap with aggravation, but is probably more susceptible to use in relation to a non-progressive disease, or at least a static condition. It relates to the heightening of the effects of the disease on the individual, where the sufferings increase.
6. "Acceleration" probably relates to progressive conditions. Mr Dohrmann used the word in the passage set out above. A progressive disease is one that, running its ordinary course, increases in gravity until the climax is reached - its progress to the end result not being susceptible of being permanently arrested, but susceptible of being hastened by external stimuli. Such a disease may increase the tempo of its progression and produce a result of a kind which a lesser progression may not have produced at all; it may produce a more extensive result or it may produce sooner the same result as that which without the acceleration of its progression the disease might have produced.
7. In an appropriate case, consideration must include the possible effect of the natural progression of a pre-existing condition and, to the extent the evidence permits, the contribution of the employment will have to take into account the contribution of the natural progression to the worsening of the condition. See also Vos Construction & Joinery Pty Ltd v Norton-Smith [2016] TASSC 38 at [25]- [26]. That appears to be relevant to the appellant's claim.
8. For the employment to be a contributing factor under par (b), there must be an incident or state of affairs to which the worker was exposed in the performance of their duty, and to which they would not otherwise have been exposed; some event or characteristic of the work or the conditions in which it was performed. In the case of an aggravation of a disease, the aggravation does not have to arise out of or in the course of the employment; there is no requirement for a temporal connection with the employment. Where one of the outcomes or consequences exists, the question is simply whether the employment has the requisite degree of causal connection.
9. It will be recalled that the primary judge said the symptoms on 4 May were an aggravation of the underlying degenerative condition. Of course, it is correct to say that on 4 May 2018 the appellant suffered an increase in the difficulties emanating from his pre-existing condition, and in that sense it became more serious. For that reason, it is strictly correct to speak of an aggravation of the pre-existing condition on that day, but it may be a little misleading. That is because it tends to shift focus away from the ongoing situation over a long period of time. Mr Dohrmann suggests there was ongoing aggravation of the underlying disease by the general employment conditions over a number of years. Symptoms spontaneously emerged on 4 May. Looked at in isolation, that might imply only an increase in the consequences of the underlying disease pathology without more.
10. Indeed, at least at one point, senior counsel for the appellant appeared to advance the proposition that the pre-existing disease, although generally progressive in nature, was shown to have stabilised and been static for a period of some significance; on that basis, there was a work-related aggravation of the static condition. But there is Mr Dohrmann's specific statement that conditions of the appellant's employment over time accelerated the progress of the pre-existing condition to the stage reached on 4 May. The material therefore shows a scenario of an acceleration, over a lengthy period, of a pre-existing non-work-related progressive disease.
11. In terms of the causative factor in this case, it is the contribution of the conditions of employment over that lengthy period that is important. Under par (b), the question is simply whether "the employment" had the requisite causal connection to the worsening. It is within the scope of the causative element in the extended definition for the appellant to rely on features or conditions of the employment over a number of years up to and including 4 May. The primary judge correctly identified the error of focussing on whether an injury per se, or insult or process, occurred on 4 May. As his Honour said, the issue is the connection between the symptoms and the "employment generally": [55].
12. The grounds of appeal need to be considered with those things in mind.

1. Four grounds attack specific statements and steps in the primary judge's reasoning process. Ground 1 alleges error in the statement that a finding that employment was a major contributing factor to the aggravation would not be sufficient to make the injury compensable within s 25(1) and the extended definition. Ground 2 alleges error in the statement that the question came down to whether it was reasonably arguable there were possible causes of the appellant's pain other than his employment "when the question was whether the evidence ... identified another major or most significant factor which at a later date with additional evidence, might be elevated to a major or most significant factor".
2. Ground 3 was abandoned. Grounds 4 and 5 relate to the passage from [63] of his Honour's judgment as set out above. By ground 6 the appellant complains to this Court that no reasonable tribunal could, on the evidence presented, have found an arguable case when there was "any more major or more significant causative factor to the aggravation other than the employment".

1. Senior counsel for the appellant dealt with grounds 4 and 5 first. There is good cause for doing the same. Ground 4 alleges an error in law in concluding that it was implicit in Mr Dohrmann's opinion that natural progression may also have played a role in the onset of symptoms on 4 May. The appellant submits that on no reasonable view could an implicit possible causator displace, without more evidence and in the face of the unchallenged material from Mr Dohrmann, the employment as the major or most significant contributing factor. The appellant says natural progression of the pre-existing condition was not put forward by Mr Dohrmann as a causative factor, nor was it argued as such by the respondent.
2. It seems that the respondent's reliance on the significance of natural progression did not emerge until the hearing before the primary judge. The appellant's argument is that on the evidence, the progression of the disease was not shown to have any significance so as to displace the conclusion that the employment was the major or most significant contributing factor to the aggravation. Specific reference was made to the radiological results set out by Mr Dohrmann. An MRI scan on 7 March 2018 showed extensive multilevel lumbar spondylosis with stenosis of varying degrees at different levels. A scan done on 17 May 2018 showed no integral change when compared to the first one. The appellant submits that there was no evidence that natural progression, as opposed to long-term repetitive employment, was responsible for the incapacity commencing on 4 May.
3. I have already set out that part of Mr Dohrmann's second report in which he responds to point 9 of the solicitor's letter. The solicitor sought confirmation of Mr Dohrmann's verbal agreement with the proposition (among others) that the appellant's condition was a natural progression of an underlying disease. In fact, Mr Dohrmann does not confirm that he agreed with the proposition, but nor does he deny that is what he said.
4. Further, it will be recalled that Mr Dohrmann's response to point 8 of the letter is that he agrees there appears not to have been any additional insult or process on 4 May "that could be identified as having contributed to any pre-existing - at least partially work-related - lumbar degenerative condition". Later in the report there is the passage, set out above, in which Mr Dohrmann says the appellant's employment "has contributed to the acceleration of [lumbar spondylosis] by way of aggravation over many years ...". [My emphases.]
5. When the reference to the lumbar condition being degenerative is combined with the statement that the employment contributed to the "acceleration" of that condition, the primary judge's impugned finding was one that was reasonably open to him. I think it is implicit in Mr Dohrmann's reports that natural progression may have played a role in the onset of symptoms on 4 May. In my view, it is plain that the statements to which I have referred do not foreclose the possibility of factors other than the employment contributing to the aggravation.
6. On the contrary, the allusion to the degenerative pre-existing condition, in the context of saying the employment was "a" contributing factor, or made "some" contribution, makes sufficient room for the natural progression to also be a contributing factor. In light of these statements, I do not see how the radiological evidence, given the short time between scans, is of any assistance to the arguments. These grounds must fail.

1. Ground 1 alleges the primary judge erred in making the statement:

"A finding that employment was a major contributing factor to an aggravation would not be sufficient to make the injury compensable ...".

1. In my view, the statement is correct. Simply by a literal approach to the causative requirement, something which is said to be a major contributing factor does not qualify as the major or most significant contributing factor. If that was all that was established at a full hearing, the appellant would fail. The absence of something else which may qualify as a major or significant factor does not transform "a" major contributing factor into the major or most significant factor. Further, and perhaps more significantly, the argument ignores Mr Dohrmann's references in the second report to the employment merely making "some contribution" to the pre-existing condition, and "contributing" to its acceleration. It is the whole of the material that needs to be considered.
2. As shown when dealing with grounds 4 and 5, natural progression of the disease was identified as a causative factor. Plainly enough, that may be a factor of some significance. Depending on the evidence, it might well mean that the appellant could not establish causation to the requisite degree when the claim was the subject of a full hearing. The issue is simply whether the evidence leaves open, as reasonably arguable, the question of whether the causative element is satisfied: St Helens Oysters Pty Ltd v Coatsworth [2007] TASSC 90, 17 Tas R 43 at [10].
3. By ground 2, the appellant argues that the primary judge was wrong to say that the ultimate question "came down to whether the evidence permitted a reasonable argument that there were other possible causes of the appellant's pain ... that is employment which might qualify as a major or most significant factor". The appellant says that the correct question was whether the evidence identified another major or most significant factor as opposed to another possible cause, which, at a later date with additional evidence, might be elevated to a major or most significant causative factor.
4. As argued, the second ground involves consideration of s 81A(2AA) of the Act. Section 81A provides that an employer who disputes liability to pay compensation must within a certain time serve written notice of the dispute, the reasons for the dispute and refer the matter to the Tribunal. Section 81A(2)(b) requires a referral to the Tribunal to be accompanied by all evidentiary material on which the employer intends to rely at the hearing of the matter. Subsection (2AA) provides that if an employer fails to lodge evidentiary material under subs (2)(b), the employer may not rely on that material unless the Tribunal otherwise allows.
5. The appellant argues that it is unlikely that the respondent, at a later trial, would obtain leave to adduce further evidence. Accordingly, the appellant says, it is plain that an employer "must put his or her best foot forward at the s 81A application and a skeleton or embryonic case will not and should not be enough to justify" not paying compensation.
6. Of course, the submission assumes that s 81A(2AA) applies to the full hearing. The assumption is unfounded. Section 81A appears in Pt VII of the Act - "Payment of compensation and related matters". The general provisions as to the resolution of claims appear in Pt V - "Dispute Resolution". Text and context strongly suggest otherwise. There is nothing in the legislative scheme to suggest that s 81A(2AA) applies to a full hearing of a claim. There is no justification in reading s 57 (above) - contained within Pt V - as subject to s 81A(2AA).
7. In its terms, the ground seems to contemplate the identification of more than one "major or most significant factor". At least as far as the alternative in that phrase is concerned, that is something which according to ordinary language, cannot happen. The ground might be best interpreted as an argument that where employment is shown to be a major contributing factor, an employer needs to identify a causative factor of such significance that it displaces the employment. However, the essential flaw in the appellant's argument is that, in effect, it imposes a requirement on an employer to prove employment was not the major or most contributing factor, where employment has been identified as a contributing factor.
8. What is determinative is the proper approach to a s 81A referral. A reasonably arguable case will exist if it is reasonably arguable on the material or identified deficiencies or weakness in the claim that, following a contested hearing the claim may be rejected. Where there is a variety of potential causes, an employer may show a reasonably arguable case by identifying in the evidence a plausible potential cause which is inconsistent with liability. See St Helens Oysters Pty Ltd v Coatsworth (above) at [14]. That is the situation here.
9. In my view these grounds have no merit.

1. That leaves ground 6. In argument, the appellant agreed that the fate of this ground is dependent on the resolution of the other grounds. It must follow that it was open to the primary judge to make the determination that it was reasonably arguable the employer had no liability.
2. As I said at the outset, in my view the appeal should be dismissed.