Safety, Rehabilitation and Compensation Act 1988 (Cth), ss 4, 5A, 5B, 14

Bailey v Broadsword Marine Contractors Pty Ltd [2017] FCAFC 219

Sullivan v Civil Aviation Safety Authority [2014] FCAFC 93

Brigginshaw v Brigginshaw [1938] HCA 34; (1938) 60 CLR 336

Makita (Australia) Pty Ltd v Sprowles [2001] NSWCA 305

Military Rehabilitation and Compensation Commission v May [2016] HCA 19

Prosegur Australia Pty Ltd v Higgerson [2024] FCA 203

Asioty v Canberra Abattoir Pty Ltd [1989] HCA 40

Federal Broom Co Pty Ltd v Semlitch [1964] HCA 34

Caldipp Pty Limited t/as Slaven Motors v Delov [2002] FCAFC 352

Tippett v Australian Postal Corporation [1998] FCA 335

Commonwealth v Beattie [1981] FCA 88

Comcare v Martin [2016] HCA 43

Comcare v Wuth [2022] FCAFC 42

1. Darren Doolan works on trains. He has an inguinal hernia which he attributes to a lifting incident in his employment by Pacific National Services Pty Ltd (Company), a licensee under the compensation scheme established under the Safety, Rehabilitation and Compensation Act 1988. He lodged a claim for compensation which was refused by primary determination[1] and on reconsideration[2]. Unhappy with this result, Mr Doolan applied for review by the Tribunal.
2. The scope of disputation between the parties narrowed somewhat during the hearing. Three issues remain to be determined by the Tribunal:

(a) the facts of Mr Doolan's compensation claim; > > (b) whether Mr Doolan suffered an 'injury' which satisfies: > > > (i) the threshold of a 'disease'; or > > > > (ii) the threshold of an 'injury (other than a disease)' or an aggravation of such an injury; and if so > > (c) whether he is entitled to payment of compensation in respect of the 'injury'.

1. I am satisfied the following relevant facts are established by the documentary and oral evidence before the Tribunal.
2. Mr Doolan is a qualified locomotive driver employed by the Company. His duties involve operating freight trains, including shunting and marshalling rolling stock. In 2020, he was assigned to the Company's Willow Tree depot.
3. On 13 October 2024, Mr Doolan engaged in duties with a co-worker_,_ Dale Hickey. A bank engine locomotive failed. Mr Doolan experienced no difficulty climbing ladders and moving around the locomotive when attempting to ascertain the reason for the failure.
4. As I understand the evidence, Mr Doolan and Mr Hickey moved the bank engine locomotive to a siding, where it was stationed for repair.
5. There is conflicting evidence of what then occurred.
6. Mr Doolan explained he was standing on the ballast (the loose rock base underlying the railway tracks) next to the locomotive when he lifted a tool bag up to Mr Hickey, who was standing on the footplate of the locomotive. On Mr Doolan's evidence, the bag contained tools, including a pipe wrench, some 20mm to 30mm spanners, a large hammer, at least 3 point clips, screw drivers, a torch and a form book, as well as 6 to 8 auto coupler lifters (he gave evidence of counting 6 auto coupler lifters and noticing there were a couple more in the bottom of the bag which he did not count). He estimated the bag weighed 20 kilograms and explained Mr Hickey was going to place the bag into the storeroom on the locomotive.
7. Mr Hickey agrees he was standing on the locomotive footplate and Mr Doolan was standing on the ballast below. Mr Hickey explained that, as the locomotive was to be left in the siding, he and Mr Doolan needed to unpack their gear from the locomotive, which included kit kept on bank engines in bags. In doing this, he passed items from the train to Mr Doolan to place on the roadway. This account is not consistent with Mr Hickey's written statement, in which he described Mr Doolan lifting items from the roadway to the footplate on the locomotive. Little turns on this. On Mr Hickey's evidence, the last bag was the heaviest as it contained tools and auto coupler lifters for different trains. Mr Hickey provided photographic evidence of the bag, but the photographs were taken at a later time and there is no firm basis on which to conclude the contents shown in Mr Hickey's photographs are the same as the contents in the bag in the incident on 13 October 2024.
8. Whichever of these accounts is correct, whether Mr Doolan was raising or lowering the bag, the salient point is that in bearing the weight of the bag at or above chest height while standing on the loose stones of the ballast, Mr Doolan experienced a sudden sharp burning pain in the right side of his lower abdomen which caused him to drop the bag and utter an expletive. On Mr Hickey's evidence, Mr Doolan said "I think I've done something to my guts" and told him it was like being punched in the stomach.
9. Mr Hickey and Mr Doolan both gave evidence Mr Doolan immediately went to the shift supervisor, Michael Wilson, who was standing next to a vehicle 20 to 25 metres away, looking at the locomotive. They both agree there were two other people present on the locomotive: two fitters in the engine bay who were investigating the reason for the bank engine failure. I understand these people declined to give evidence in these proceedings.
10. Mr Doolan's evidence is that he told Mr Wilson what had happened and that he had hurt himself, but Mr Wilson was otherwise engaged, texting on his phone, and told Mr Doolan he would be going home soon. Mr Wilson stated he has no recollection of Mr Doolan reporting an injury on 13 October 2024.[3] In his evidence, Mr Wilson accepted he is responsible for documenting any incident/injury reports.[4]
11. Mr Doolan asserts he subsequently informed his usual supervisor, Marc Sobbel (a Northwest NSW Operations Supervisor), of the incident and alleged injury a few days later, on his return from leave. Mr Sobbel stated he has no recollection of this occurring. It was Mr Sobbel's evidence that he was responsible for documenting verbal injury reports from employees, and he had done so on many occasions.
12. Mr Doolan alleges he informed another supervisor, Matthew Jones, of the incident and alleged injury. Mr Jones has no recollection of this occurring.[5]
13. There is no contemporaneous documentation of the incident Mr Doolan alleges occurred on 13 October 2024.
14. This notwithstanding, I am satisfied it is likely an incident occurred on 13 October 2024, the facts of which are largely as Mr Doolan and Mr Hickey described, noting the conflict in Mr Hickey's evidence. I accept Mr Doolan's account of experiencing a sharp burning pain in his lower abdomen on the right side when lifting the tool bag.
15. There was no serious challenge to Mr Doolan's credit. He was a straightforward witness who gave cogent and consistent evidence. Even though there is no contemporaneous written record, I also consider it is probable he immediately attempted to report the incident verbally to his shift supervisor Mr Wilson, who was standing nearby, and so find.
16. There is some controversy over the weight of the bag and what it contained during the incident on 13 October 2024. On Mr Hickey's evidence the bag went missing and was subsequently located a few days later in a different depot. On the evidence of Mr Doolan, Mr Hickey and Marc Sobbel it is likely the bag contained tools, such as those Mr Doolan described, and a number of auto coupler lifters. Mr Sobbel gave evidence there would normally be 2-3 auto coupler lifters on site at the Willow Tree depot, and he had never seen any more than 2 or 3 auto coupler lifters at once in a bag.[6] On Mr Doolan's evidence there were more auto coupler lifters in the bag than should have been: he counted 6 but thought there might have been a few more at the bottom of the bag. He explained that auto coupler lifters are made specifically for specific classes of locomotives and, commonly, there would be auto couplers for the 90 class locomotive which failed and for a TT class locomotive, as well as spares.
17. On evidence provided by Rick Patterson (a Northwest NSW Operations Supervisor), an auto coupler lifter for a 90 class locomotive weighs approximately 1.23 kilograms.[7] This is broadly consistent with Mr Sobbel's evidence.
18. There is no sound basis on which to calculate or accurately estimate the weight of the tools that were in the bag Mr Doolan and Mr Hickey moved on 13 October 2024.
19. From this distance, doing the best with the available evidence, it is likely the bag weighed at least 10 kilograms, although it might have weighed up to 20 kilograms, as Mr Doolan contends. It is not necessary to go further with this, as the weight of the bag Mr Doolan lifted is not determinative.
20. On Mr Doolan's evidence, he returned home after completing his shift on the night of 13 October 2024 and went to bed. He explained that the burning pain subsided somewhat overnight and the next morning he noticed a small lump in his groin/pubic region.[8] He returned to work and for several days undertook his usual duties with minor pain and a lump near my groin.[9] He asserts he spoke with Mr Jones about the injury and his dissatisfaction with the way it had been handled by Mr Wilson, but the conversation was interrupted and he resumed his duties. His uncontested evidence is that the pain was higher when I arrived home, and my wife booked me a doctor's appointment.[10] In a subsequent account, Mr Doolan explained A few days later [after conversing with Mr Jones] I was still in pain so I asked my wife to book a doctors appointment.[11]
21. On 8 November 2024, Mr Doolan consulted Dr Haidar Tanny, a general practitioner. On Mr Doolan's evidence, the appointment had been made on 14 October 2024 and it was the first available. The doctor referred Mr Doolan for an ultrasound scan and noted:

a protruding swelling while standing from the right inguinal region > > was lifting a 30 kg bag at work and felt a burning rip in that area 3 weeks ago > > - pain 7-8/10 > > - interferring with function > > - for USS to assess swelling > > ... > > Swelling on inspection of Right inguinal region - cough test +ve > > ... > > Diagnosis: > > Moderate, Acute Hernia [12]

22. At or about this time, on the evidence of Mr Doolan and Mr Hickey, they both met with Mr Sobbel to discuss Mr Doolan's hernia and a separate trip incident involving Mr Hickey. They each allege Mr Sobbel was dismissive of Mr Doolan's injury account. Mr Sobbel gave evidence he has no recollection of this event.
23. On 17 November 2024, Mr Doolan completed a Pulse survey in respect of his employment:

I injured myself a work and a certain supervisor > > said you're going home soon, know I need an > > operation I can't afford [13]

24. Mr Doolan took a period of leave and booked another appointment with [his] regular doctor because the lump was growing and becoming more regularly painful.[14]
25. On 11 December 2024, Mr Doolan consulted Dr Sarah Shabihkhani, his usual treating general practitioner. The doctor did not issue a medical certificate but issued a further request for an ultrasound scan and noted:

1) Right side ing hernia > > related to work > > needs to claim fro it through woc [15]

26. On 18 December 2024, Mr Doolan again consulted Dr Shabihkhani who noted they sent him home for the f.u. on his worker s comp.[16] The doctor issued a medical certificate, stating Mr Doolan's right sided inguinal hernia happened at work lifting a heavy object, and specifying a lifting restriction of 5 kilograms and a standing tolerance no longer than 1 hr.[17]
27. At or about this time, Mr Doolan lodged a claim for compensation.[18] In the compensation claim form, the claimed injury is Hernia affecting his Groin (right side) which occurred at 2230 on 13 October 2024 when remarshalling locomotive and lifting a crewbag witch had auto lifters in it up to footplate.[19]
28. On 23 December 2024, Mr Doolan provided information about the alleged injury and related events to EML Solutions Pty Ltd, the Company's claims agent.[20]
29. He also consulted Dr Shabihkhani on 23 December 2024. The doctor reported:

On physical exam diagnosed , needing and ultrasound to confirm > > 2) ... there is no pre existing condition relating to the current complaint > > 3) Heavy object lifting at work, can cause this problem, and he states it did > > ... [21]

30. On 2 January 2025, an ultrasound scan was reported to show:

There is a moderate sized direct inguinal hernia that contains bowel with the neck of the hernia measuring 16 x 11mm. The herniated content is reducible and focal tenderness is noted with probe pressure.[22]

... > > the right groin pain is getting worse sometimes > > avoiding heavy lifting > > ...[23]

32. On 9 January 2025, Dr Shabihkhani referred Mr Doolan to a general surgeon:

... for opinion and management of a work related injury. He had a heavy object lifting at work, ended up having a right sided inguinal hernia which is reducible but symptomatic.[24]

33. On 12 February 2025, EML issued a determination refusing Mr Doolan's compensation claim.[25] Mr Doolan requested reconsideration of this determination. On 10 April 2025, EML issued a reconsideration decision which affirmed refusal of Mr Doolan's compensation claim.[26] On 20 May 2025, Mr Doolan lodged an application for review of this decision.
34. On 7 August 2025, Dr Rejkumar Srinivasan, a general surgeon, reported Mr Doolan's work related right-sided inguinal hernia developed in October 2024 when he lifted a heavy object above his head on a platform.[27] Surgical repair of the hernia was recommended.
35. On 26 August 2025, Dr Kim Edwards, a general surgeon, conducted a telehealth examination of Mr Doolan and produced a medicolegal report for the Company.[28] Dr Edwards reported a diagnosis of right inguinal hernia and concluded that Mr Doolan's employment was not a significant contributing factor to the hernia: his hernia is not a work related matter.[29]

1. Mr Doolan claims his right inguinal hernia occurred when he lifted the tool bag on 13 October 2024. He contends a causal connection between the lifting event, the sudden onset of sharp burning pain in the lower right side of his abdomen and the appearance of a lump in his right groin area. In support of these contentions, he relies on the evidence of Dr Tanny, Dr Shabihkhani and Dr Srinivasan. In his submission, the inguinal hernia is an injury in respect of which he is entitled to payment of compensation.
2. The Company disagrees. In the Company's submission, even if the facts alleged by Mr Doolan in respect of the lifting incident are accepted, the expert medical evidence of Dr Kim Edwards, a consultant surgeon, is against a causal connection between the lifting incident and the onset or aggravation of the inguinal hernia. The Company asserts the opinion Dr Edwards expressed and the reasoning on which it is based are unequivocal, cogent and strongly supported by relevant medical research. The Company argues Dr Edwards' evidence is more reliable and persuasive than the evidence of Dr Tanny, Dr Shabihkhani and Dr Srinivasan which relied on Mr Doolan's account and lacked any detailed rationale, amounting to bare ipse dixit.
3. The controversy turns on the statutory thresholds set out in the definition of 'injury' in s 5A of the Act:

(1) In this Act: > > injury means: > > (a) a disease suffered by an employee; or > > (b) an injury (other than a disease) suffered by an employee, that is a physical or mental injury arising out of, or in the course of, the employee's employment; or > > (c) an aggravation of a physical or mental injury (other than a disease) suffered by an employee (whether or not that injury arose out of, or in the course of, the employee's employment), that is an aggravation that arose out of, or in the course of, that employment; > > but does not include a disease, injury or aggravation suffered as a result of reasonable administrative action taken in a reasonable manner in respect of the employee's employment.

4. The word 'disease' is given meaning in s 5B:

(1) In this Act: > > disease means: > > (a) an ailment suffered by an employee; or > > (b) an aggravation of such an ailment; > > that was contributed to, to a significant degree, by the employee's employment by the Commonwealth or a licensee. > > (2) In determining whether an ailment or aggravation was contributed to, to a significant degree, by an employee's employment by the Commonwealth or a licensee, the following matters may be taken into account: > > (a) the duration of the employment; > > (b) the nature of, and particular tasks involved in, the employment; > > (c) any predisposition of the employee to the ailment or aggravation; > > (d) any activities of the employee not related to the employment; > > (e) any other matters affecting the employee's health. > > This subsection does not limit the matters that may be taken into account. > > (3) In this Act: > > significant degree means a degree that is substantially more than material.

5. The correct approach and the questions to be addressed were settled by the High Court in Military Rehabilitation and Compensation Commission v May.[30] These are:

(a) Does the evidence amount, relevantly, to something that can be described as an "ailment", being a physical or mental ailment, disorder, defect or morbid condition? > > (b) If so, was that state contributed to in a significant degree by the employee's employment such that there is a 'disease'? > > (c) If not, does the evidence demonstrate the existence of a physical or mental injury (in the primary sense of that word) or the aggravation of such an injury? > > (d) If so, did that injury or aggravation arise out of, or in the course of, the employee's employment?

1. On the evidence of Dr Shabihkhani, Dr Tanny, Dr Edwards and the ultrasound scan report on 3 January 2025, I am satisfied Mr Doolan has a right inguinal hernia.
2. Dr Edwards explained the hernia is an area of weakness or a gap in the wall of Mr Doolan's right inguinal canal into which subsisting material protrudes. I accept this description and so find.
3. Even though evidence of an identifiable physiological change is not required to establish the existence of an 'ailment',[31] Mr Doolan's right inguinal hernia meets the definition of an 'ailment' in s 4(1) of the Act.
4. With regard to the onset of the ailment, there is scant relevant contemporaneous evidence.
5. On the clinical notes of Dr Shabihkhani on 11 and 18 December 2024,[32] the hernia was present at that time and when Mr Doolan lodged the compensation claim.
6. The hernia was probably present on 8 November 2024. Dr Tanny noted a diagnosis of Moderate, Acute Hernia on the history provided by Mr Doolan (lifting a 30kg bag at work and felt a burning rip in that area 3 weeks ago) and clinical examination grounds, including swelling, discomfort and a positive cough test.[33] It is not entirely clear what the doctor meant by 'Acute', although it is likely he proceeded on the history Mr Doolan provided. Even though the doctor noted Mr Doolan was complaining of pain and interference with function, Dr Tanny did not issue a medical certificate in respect of any incapacity to work. Mr Doolan continued to undertake his normal shifts and duties, prior to taking leave.
7. There is no prior medical record of the hernia ailment.
8. Mr Doolan gave evidence he first noticed a lump in or near his right groin on the morning of 14 October 2024 after experiencing burning pain in that area the previous evening, when lifting the tool bag at work. Even on this account, which was not seriously challenged, it is not clear when the lump emerged in his right groin, or whether this occurred suddenly or gradually by degrees over a period.
9. On Dr Edwards' evidence, the presence of a lump in Mr Doolan's right groin on the morning of 14 October 2024 could be consistent with the existence of a right inguinal hernia at that time. As I accept Mr Doolan's account of noticing the lump in his right groin on the morning of 14 October 2024, it is probable the hernia ailment was present at that time.
10. Dr Edwards considered it is possible the right inguinal hernia might well have been physiologically present, albeit asymptomatic and undiagnosed, prior to 14 October 2024. He noted the absence of medical evidence to indicate this was so. This possibility remains open, albeit not proved.

1. For Mr Doolan's hernia ailment to be a 'disease' under the terms of s 5B of the Act, evidence is required his employment contributed to it to a degree that is substantially greater than material:

1) In this Act: > > disease means: > > (a) an ailment suffered by an employee; or > > (b) an aggravation of such an ailment; > > that was contributed to, to a significant degree, by the employee's employment by the Commonwealth or a licensee. > > (2) In determining whether an ailment or aggravation was contributed to, to a significant degree, by an employee's employment by the Commonwealth or a licensee, the following matters may be taken into account: > > (a) the duration of the employment; > > (b) the nature of, and particular tasks involved in, the employment; > > (c) any predisposition of the employee to the ailment or aggravation; > > (d) any activities of the employee not related to the employment; > > (e) any other matters affecting the employee's health. > > This subsection does not limit the matters that may be taken into account. > > (3) In this Act: > > significant degree means a degree that is substantially more than material.

2. Unless the relevant materials are sufficient to positively satisfy the Tribunal on this point, no such finding can be made.
3. It is important to understand that factual findings are made on the basis of reasonable satisfaction. Mere possibility or conjecture is not sufficient, however real the possibility might be. Even though an inference of probability might properly be drawn where it is properly supported in the matrix of evidence in any case, this does not mean the Tribunal can choose between guesses. Doing so might be likened to flipping a coin. Reasonable satisfaction requires findings to be made and inferences to be drawn on the basis of relevant materials of probative value. This is so, even though degrees of probability might arise on the relevant evidence. Where the contested fact is of central or pivotal importance, greater caution is applied when evaluating the foundation on which it is raised.[34] As Dixon J said in the oft cited case of Brigginshaw v Brigginshaw[35]:

The seriousness of an allegation made, the inherent unlikelihood of an occurrence of a given description, or the gravity of the consequences flowing from a particular finding are considerations which must affect the answer to the question whether the issue has been proved to the satisfaction of the tribunal.[36]

4. Assertions of causality drawn from commonsense are no answer, however tantalising this might be. About this, two things should be said. Firstly, a cause which one person might consider to be commonsense, another might not. This is especially so when ordinary or inexpert notions of causation run up against expert evidence. On this point, it is apposite to recall McHugh J's remarks in March v Stramare (E & M H) Pty Ltd:[37]

Indeed, I suspect that what commonsense would not see as a cause in a non-litigious context will frequently be seen as a cause, according to commonsense notions, in a litigious context. This is particularly so in many cases where expert evidence is called to explain a connexion between an act or omission and the occurrence of damage. In these cases, the educative effect of the expert evidence makes an appeal to commonsense notions of causation largely meaningless or produces findings concerning causation which would often not be made by an ordinary person uninstructed by the expert evidence.[38]

5. Secondly, in law, causation is always purposive and, in a statutory context, it is to be determined by reference to the statutory text construed and applied in its statutory context in a manner which best effects its statutory purpose.[39] In the context of s 5A of the Act, the phrase 'as a result of' in s 5B(1) of the Act has been found not to import a 'commonsense' notion of causation.[40] The alternative basis of liability established under s 5A, in respect of an 'injury (other than a disease)' applies a different threshold, namely 'arising out of, or in the course of' the person's employment. The temporal connexion to which this refers does not require a causal nexus to be established.
6. There is scant medical evidence to support Mr Doolan's assertion the action of lifting the tool bag on 13 October 2024 significantly contributed to his right inguinal hernia ailment.
7. The evidence of Dr Tally, Dr Shabihkhani and Dr Srinivasan does not address the degree of employment contribution to Mr Doolan's hernia ailment in any detail. Even on a generous interpretation, their evidence does not provide a cogent explanation of the degree to which lifting contributed to the onset or aggravation of Mr Doolan's hernia, if at all. Dr Shabihkhani's response to the questions put to her does no more than raise the possibility of a causal contribution between heavy lifting and the inguinal hernia: Heavy object lifting, can cause this, and he states it did.[41] Dr Tanny diagnosed the hernia as Acute,[42] which might suggest a hernia of sudden onset. Even if this is correct and the doctor accepted Mr Doolan's account, his clinical note does not expressly refer to the lifting activity on 13 October 2024 as a significant contributory factor to the hernia.
8. Dr Edwards' expert opinion evidence is that Mr Doolan's employment was not a significant contributing factor to the hernia.[43] He supported this opinion, to which he unequivocally adhered, with reference to a number of medical research papers.[44] He explained the research literature does not support a causal association between heavy lifting and the causation of inguinal hernia, and stated:

The cause of inguinal hernias remains uncertain. Risk factors are described, such as smoking and a positive family history, and it is thought that sustained increases in intra-abdominal pressure may be a risk factor. Kilnge et al write: "the linear rise of prevalence rates observed in adults (years 15+) most likely are not explained by one factor but rather indicate a multi-factorial biological problem_"._ > > ...[45]

9. In oral evidence, Dr Edwards explained he did not undertake a complete review of the medical research literature in respect of hernia causation but used search criteria to identify research literature relevant to the causation of hernia in the library of the Royal Australian College of Surgeons. He informed the Tribunal, in his searches, he did not find any research articles which supported a causal link between lifting activity at work and causation of inguinal hernia. He acknowledged causation of hernia is the subject of ongoing controversy and more recent research may go to this point and explained this does not change his opinion.
10. This is somewhat problematic as the precise methodology and extent of the doctor's inquiries are not set out in his report, and the extent to which his expert opinion evidence is drawn from his own specialised knowledge (based on training, study or experience) or from what he discovered in the research articles he came across is unclear. In a court, this might be contested when determining the admissibility of his opinion evidence. The opinion rule,[46] which bars admission of opinion evidence to prove the existence of a fact about the existence of which the opinion was expressed, does not apply if the expert witness has specialised knowledge based on training, study or experience, and their opinion evidence is wholly or substantially based on that knowledge. No such issues of admissibility arose in this case, as the Tribunal is not a court, and it is not bound by the rules of evidence, including the opinion rule.
11. The real question is the reliability and probative value or usefulness of Dr Edwards' opinion evidence and the weight it should be given. In many cases where compensation is involved, and the particular ailment is the subject of ongoing research and controversy at the boundary of medical scientific knowledge, the Tribunal is confronted with divergent expert opinion evidence. This is not such a case. Dr Edwards is the sole expert witness, briefed by the Company. The doctor gave an undertaking to provide impartial assistance to the Tribunal and confirmed he approached his brief in this manner. While a comparative examination is not possible, it does not mean the doctor's opinion evidence cannot or should not be scrutinised or, because Dr Edwards is the sole expert witness, his opinion evidence must be given greater weight than other relevant evidence.
12. In a case such as this, in which Mr Doolan is unrepresented and running his case without apparent legal support or detailed experience or knowledge of the applicable law, the Tribunal bears a greater load when scrutinising and evaluating Dr Edwards' evidence, albeit ably assisted by counsel for the Company. As I explained to Mr Doolan, there are limits to this, however. The Tribunal's inquiry is for the purposes of evaluating the evidence before it and deciding matters on the basis of reasonable satisfaction. Even though a great deal of latitude can be given to an unrepresented party, the Tribunal must remain impartial when making the correct or preferable decision on the materials before it, and it is for Mr Doolan to present his case as he sees fit. I am satisfied he was given a reasonable opportunity to do so.
13. At the level of principle, the primary duty of an expert witness is to furnish the trier of fact with criteria enabling evaluation of the validity of the expert's conclusions.[47] As evidence given by an expert in Tribunal proceedings is essentially opinion based on facts, the facts (including assumptions) and the reasoning on which the opinion is based should be clearly stated so these can be examined and evaluated by the Tribunal in the context of the whole of the relevant evidence when determining the value of the opinion and the weight it should be given. Fact finding based on reasonable satisfaction requires no more and it permits no less.
14. Dr Edwards sets out the factual matters on which his opinions are based in the 'History', 'Current Symptoms', 'Examination' and 'Investigations' sections of his report. He gave further relevant detail in his oral evidence. As I comprehend his evidence, it was on the information Mr Doolan provided and his clinical findings (albeit via a remote visual examination over Telehealth), as well as the extensive medical records and other materials with which he was briefed by the Company, that his diagnostic opinion was based.
15. On the question of contributory or causal factors, the doctor stated:

The most significant factor appears to be the family history. As indicated, this results in approximately an eight times increase in the risk of Mr Doolan suffering a hernia In my opinion, Mr Doolan's employment is not a significant contributing factor. > > In my opinion, Mr Doolan's employment is not a significant contributing factor. > > Undiagnosed hernias are found in approximately 20% of cases where laparoscopy is carried out for other reasons. In approximately 20-25% of patients who have a hernia on one side, an asymptomatic hernia is found on the other side. > > To support my evidence based opinion that his hernia is not a work related matter, I include the following extracts from peer reviewed published medical journals and books...[48]

16. On Dr Edwards' evidence, a causal nexus between employment, particularly strenuous employment involving lifting, and inguinal hernia is not supported by research literature he identified. He acknowledged the possibility of such a causal nexus is the subject of ongoing research and continuing controversy. This notwithstanding, he considered the possibility to be remote and drew support for his conclusion that Mr Doolan's hernia is not work-related from the literature he identified.
17. I have not been taken to, and I have not found, any evidence Mr Doolan has a family history of inguinal hernia. The factual basis of Dr Edwards' opinion that Mr Doolan's family history was the most significant factor is unclear. In oral evidence, the doctor explained the inguinal hernia could have been pre-existing, but he found nothing to suggest this.
18. These considerations aside, and more importantly, the doctor's opinion that Mr Doolan's employment is not a significant contributing factor and that his hernia is not a work related matter needs to be properly understood.
19. Without being critical of Dr Edwards, his report does not set out clear reasoning addressing the facts of Mr Doolan's case. To the extent his opinions are drawn from his expert knowledge, his report does not set out a clear rationale for the conclusion Mr Doolan's hernia is not related to his work. His rationale appears to rely on research materials he identified. More particularly, the doctor's report does not explain his reasons for concluding the burning sensation Mr Doolan felt in his right groin when lifting the tool bag before finishing work at 11:00pm on 13 October 2024 is unrelated to the thumb-sized lump in the right groin Mr Doolan discovered when showering the next morning.
20. The coincidence of lower right abdominal pain and lifting activity followed by the discovery of a lump in the right groin area might, on a commonsense view, as Mr Doolan asserts, suggest the lifting activity significantly contributed to the lump and the hernia. This runs up against Dr Edwards' expert opinion.
21. Related matters were put to Dr Edwards in oral evidence. He explained the pain Mr Doolan described could have been a muscle strain, although the burning sensation might suggest nerve involvement, but he did not consider either of these symptoms related to the hernia or the lump Mr Doolan noticed the next morning. On his evidence, the hernia would not necessarily involve any tearing of tissues associated with the inguinal canal and the pain Mr Doolan described cannot be accounted for on that basis. Dr Edwards considered it was possible the hernia might have occurred while Mr Doolan was at work or it might have been pre-existing, asymptomatic and undiagnosed, but he found nothing to suggest this.
22. Dr Edwards was unequivocal in his conclusion that Mr Doolan's employment, and lifting the tool bag in particular, would not have caused or significantly contributed to the inguinal hernia. He explained he had not come across such a causal nexus in all the hernias he had treated over many years, but he accepted he could not rule out the possibility of such a connexion, albeit remote in his opinion.
23. There is only very scant evidence to the contrary, namely the brief and untested statements of Dr Tanny, Dr Shabihkhani and Dr Srinivasan, who were not called to give oral evidence and were not required for cross-examination. Their evidence lacks any cogent reasoning.
24. On this point, I prefer and give greater weight to the expert opinion evidence of Dr Edwards.
25. There is a further question whether Mr Doolan's employment significantly contributed to an 'aggravation' of the hernia ailment.
26. Doing the best with Mr Doolan's submissions, he argues that lifting the tool bag caused his hernia to become symptomatic and the continuing pain and discomfort he experienced thereafter amounts to an aggravation injury.
27. The word 'aggravation' is defined in s 4(1) of the Act to include acceleration or recurrence. In ordinary language, it can also be understood to refer to exacerbation or worsening.
28. It has long been accepted that exacerbation of the symptoms or experience of an ailment could amount to an 'aggravation' of the ailment.[49]
29. On this basis, if it is found the employment activity Mr Doolan engaged in, lifting the tool bag, significantly contributed to exacerbate the symptoms of his inguinal hernia, the exacerbation would amount to an 'aggravation' sufficient to meet the threshold of a 'disease'.
30. There are two difficulties with this.
31. The first is that I am not positively satisfied Mr Doolan had an asymptomatic, undiagnosed right inguinal hernia on 13 October 2024. It is possible he did, although Dr Edwards found nothing to suggest this. Mr Doolan noticing a lump in his right groin on the morning of 14 October 2024 lends support to the possibility. There is not enough to make a positive finding on this point.
32. The second difficulty arises from the first. As a matter of simple logic, without a positive finding in respect of the existence of the hernia ailment on 13 October 2024, the symptoms Mr Doolan described cannot be attributed to it or found to be an aggravation of it for the purposes of the 'disease' threshold.[50]
33. These difficulties cannot be overcome by raising speculative possibilities and bare assertions clothed in commonsense notions of cause and effect against expert evidence supported by cogent reasoning and scientific research.
34. From all this it follows I am satisfied Mr Doolan does not have a 'disease' kind of injury for the purposes of s 5A(1)(a) of the Act.

1. The third question, following May, is whether Mr Doolan has an 'injury (other than a disease)' or an aggravation of such an injury.
2. Mr Doolan asserts his right inguinal hernia is an injury which occurred in the course of his employment on 13 October 2024 in the circumstances he described in the compensation claim form and in his evidence.
3. The Company disagrees.
4. The term 'arising out of, or in the course of' is expanded upon in s 6 of the Act. The relevant threshold is set out in s 6(1)(b), namely where the injury (in the ordinary sense) was sustained while the employee was at the employee's place of work, for the purposes of that employment.
5. In order to make a positive finding that Mr Doolan's claim amounts to an 'injury (other than a disease)', at the minimum, reasonable satisfaction supported by relevant material of probative value is required. The alleged injury must have the quality of being a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state (noting that suddenness is not an essential characteristic in all cases).[51] This must be examined in a detailed manner, fact by fact. Even though reasonably supported inferences might be drawn, possibility is not sufficient.
6. There are two scenarios raised on Mr Doolan's submissions: the right inguinal hernia occurred, or it was pre-existing and was aggravated, in the circumstances he described during the course of his employment on 13 October 2024.
7. In each scenario, Mr Doolan's case falters due to the lack of supporting medical evidence.
8. The available evidence does not support a positive finding that Mr Doolan's right inguinal hernia occurred in the course of his employment when he lifted the tool bag on 13 October 2024, even though that possibility cannot be ruled out.
9. The expert evidence of Dr Edwards weighs heavily against such a finding. On his evidence, the lifting event was unlikely to have caused the hernia to come into existence. This conclusion is supported by the medical research literature he referred to. Even though some of the research is couched in terms of risk which leaves open the possibility that lifting might be related to herniation in some cases, as Dr Edwards explained, this is controversial and unsupported in any peer reviewed study he identified, and it is not consistent with his own experience and knowledge.
10. The evidence provided by Dr Shabihkhani and Dr Srinivasan points to a different conclusion, but their evidence is very scant. It lacks cogent reasoning, and it has not been tested or explained in any way. For these reasons, it can be given little weight.
11. Dr Edwards gave a detailed explanation of the physiology of inguinal hernia: an area of weakness or a gap in the tissue of the inguinal canal which allows the protuberance of subsisting material. On his evidence, it is a natural feature of a hernia for subsisting material to protrude into the hernia 'neck'. The doctor explained that lifting a tool bag and the associated increase in intra-abdominal pressure would not cause the hernia, but activity of this kind could cause the protruding material to move in or through the 'neck' of the hernia, and this could be related to symptoms of pain or discomfort. He explained this is an essential feature or symptom of the hernia which does not significantly contribute to it, and that movement of such material in the 'neck' of the hernia can be affected by activities such as coughing, sneezing, going to the toilet and lifting, which increase intra-abdominal pressure.
12. On the doctor's evidence, if the protruding material moves easily in the neck, there would be less discomfort: conversely, the greater the protruding material and the smaller the 'neck, the greater the discomfort. Dr Edwards observed that general practitioners commonly specify lifting restrictions in hernia cases, although he did not think that many surgeons would impose such lifting restrictions as they are not supported by the research literature he identified.
13. If established by evidence or reasonably drawn inference, I accept that changes of these kinds involving the movement of material in or through the 'neck' of a hernia consequent to an increase in intra-abdominal pressure would likely amount to a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state. Dr Edwards was very clear that the likely increase in intra-abdominal pressure Mr Doolan probably experienced when lifting the tool bag would be very unlikely to result in Mr Doolan's right inguinal hernia. On this point, I give greater weight to Dr Edwards expert opinion than to the brief evidence of Dr Shabihkhani and Dr Srinivasan, to which the evidence of Dr Tanny lends support.
14. I am not satisfied Mr Doolan's right inguinal hernia arose on 13 October 2024 in the course of his employment.
15. Furthermore, the evidence is not sufficient to support a positive finding Mr Doolan's inguinal hernia was present on 13 October 2024, although that possibility is open.
16. As I have said, without such a positive finding, there is no firm basis on which I find the hernia was aggravated in the course of Mr Doolan's employment, or in the circumstances he described, lifting the tool bag, on that day. That being so, there is insufficient relevant evidence on which to make a positive finding that the physiological changes Dr Edwards described actually occurred when Mr Doolan lifted the tool bag on the evening of 13 October 2024 during the course of his employment.
17. I am not satisfied the pain he experienced is attributable to the physiological changes Dr Edwards described, although that possibility remains open. It is equally possible, as Dr Edwards explained, the pain was related to a muscular strain even though there is not sufficient evidence to make such a positive finding.
18. The threshold of 'injury' cannot be surpassed by choosing between possibilities.
19. For these reasons, I am satisfied the thresholds set out in s 5A(1)(b) and (c) of the Act are not met.
20. From this it follows Mr Doolan does not have an 'injury' for the purposes of the Act and his compensation claim cannot succeed.

1. That being so, it is not necessary to proceed further to consider issues of compensation entitlement.
2. For compensation to be payable, the threshold in s 14 of the Act must be met in respect of an 'injury'. The 'injury' must result in 'incapacity for work' or 'impairment'. Without an 'injury', compensation is not payable.
3. It is appropriate to observe in closing that even if I had found that the pain Mr Doolan experienced when he lifted the tool bag amounted to an 'aggravation' (and I have made no such finding), the available material does not establish that impairment or incapacity for work resulted. The relevant material confirms he continued to perform his usual shifts and his usual duties on and after 13 October 2024, excluding a period of absence on leave in November 2024, until Dr Shabihkhani issued a medical certificate on 18 December 2024.
4. Furthermore, it is probable the symptoms subsided overnight and were worse again after he returned home after completing his shift on 14 October 2024. This is consistent with Dr Edwards evidence it is likely Mr Doolan would experience symptoms of the hernia with activity, as protruding material moves in the hernia 'neck'. If this is correct, the subsequent symptoms would not be attributable to the 'aggravation' on lifting the tool bag on 13 October 2024. Consequently, no compensation would be payable for the 'aggravation' under s 14 of the Act.

Solicitor for the Respondent: Jack Marshall, McInnes Wilson Lawyers

[30] [2016] HCA 19, [50]-[54].

[31] Comcare v Wuth [2022] FCAFC 42, [104] and [110].

[34] Sullivan v Civil Aviation Safety Authority [2014] FCAFC 93, [120].

[35] [1938] HCA 34; (1938) 60 CLR 336.

[37] [1991] HCA 12.

[39] Comcare v Martin [2016] HCA 43, [42].

[46] Evidence Act 1995 (Cth) s 76.

[47] Makita (Australia) Pty Ltd v Sprowles [2001] NSWCA 305, [59].

[49] Asioty v Canberra Abattoir Pty Ltd [1989] HCA 40; Federal Broom Co Pty Ltd v Semlitch [1964] HCA 34; Caldipp Pty Limited t/as Slaven Motors v Delov [2002] FCAFC 352; Tippett v Australian Postal Corporation [1998] FCA 335; Commonwealth v Beattie [1981] FCA 88.

[50] Comcare v Stefaniak [2020] FCA 560.

[51] May, [45]-[47]; Kennedy Cleaning Services Pty Ltd, v Petkovska [2000] HCA 45, [39].