Ventia Australia Pty Ltd v Mawson

DETERMINATION OF APPEAL PANEL
CITATION:	Ventia Australia Pty Ltd v Mawson [2024] NSWPICMP 42
APPELLANT:	Ventia Australia Pty Ltd
RESPONDENT:	Greg Mawson
APPEAL PANEL
MEMBER:	Catherine McDonald
MEDICAL ASSESSOR:	Henley Harrison
MEDICAL ASSESSOR:	Thandavan Raj
DATE OF DECISION:	30 January 2024
CATCHWORDS:	WORKERS COMPENSATION - Workplace Injury Management and Workers Compensation Act 1998; noise-induced hearing loss; agreed deemed date of injury before last date of noisy employment; deduction sought for loss in subsequent employment; Schofield v Abigroup Limited distinguished; Rico v Roads and Traffic Authority and OneSteel Limited v Devine discussed; section 323 deduction for noisy employment overseas; Pereira v Siemens Limited discussed; Held – Medical Assessment Certificate revoked.

BACKGROUND TO THE APPLICATION TO APPEAL

On 26 September 2023 Ventia Australia Pty Ltd (Ventia) lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by Dr Kenneth Howison, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on 29 August 2023.
Ventia relies on the following grounds of appeal under s 327(3) of the Workplace Injury Management and Workers Compensation Act 1998 (the 1998 Act):
· the assessment was made on the basis of incorrect criteria, and
· the MAC contains a demonstrable error.
The delegate was satisfied that, on the face of the application, at least one ground of appeal was made out, being that in s 327(3)(d). We conducted a review of the original medical assessment, limited to the grounds of appeal on which the appeal is made.
Rule 128 of the Personal Injury Commission Rules 2021 (the PIC Rules) and Procedural Direction PIC7 – Appeals, reviews, reconsiderations and correction of obvious errors in medical disputes set out the practice and procedure in relation to the medical appeal process under s 328 of the 1998 Act. An Appeal Panel determines its own procedures in accordance with r 128(1) of the PIC Rules.
The assessment of permanent impairment is conducted in accordance with the SIRA NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4^th ed 1 March 2021 (the Guidelines) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 5^th ed (AMA 5).

RELEVANT FACTUAL BACKGROUND

Mr Mawson claims compensation from Ventia for noise induced hearing loss. Ventia does not dispute that his employment with it was noisy.
Mr Mawson commenced his working life as an apprentice fitter/machinist with Caltex, working for that company between 1971 and 1974. In 1975 and 1976 he was employed by Thames Gas Co in the United Kingdom. In 1976 he recommenced working for Caltex and remained there until 1997. He worked for undisclosed periods for Caltex in Malaysia in 1983 and the Philippines in 1995. He was employed as a hotel manager in 1997 and 1998.
He was employed by Ventia (then called Transfield Services) to work in South Australia between 1998 and 1999. He then worked for BVI Engineering in NSW as a manager.
Mr Mawson worked for Ventia between 2003 and 2015. During that period the company was called Transfield Services and Broadspectrum. His employment was primarily in NSW but he was required to travel to work interstate from time to time. He worked in Victoria for UGL Operations and Maintenance Pty Ltd (UGL) between 2016 and 2019 for three periods which total one year and nine months. The evidence is unclear as to whether he entered into a contract of employment in NSW or Victoria. Mr Mawson worked for Ventia again between June 2021 and September 2021.
Mr Mawson made a claim for compensation for 27% whole person impairment (WPI) on 15 December 2020 in which he said that the deemed date of injury was 6 September 2019 and that his last noisy employer was UGL. At that time he was retired. He gave notice of a claim against Ventia (under its former name) on 11 March 2021, relying on an undisclosed date of injury in 2016. Rather than withdrawing that claim, Mr Mawson sought to amend it on 14 October 2022, relying on a deemed date of injury of 14 October 2022 and that date was relied on in the Application to Resolve a Dispute. At that time, Mr Mawson was again employed by Ventia.
Mr Mawson based his claim on a series of reports from Dr Fagan. In the last report dated 12 May 2022, Dr Fagan assessed 49.9% binaural hearing loss, which converts to 25% binaural hearing loss. The claim in the Application to Resolve a Dispute is 27% WPI or 53.9% binaural hearing loss set out in Dr Fagan’s previous report dated 23 November 2020.
Ventia relied on a report from Dr Payten dated 27 July 2021. Dr Payten assessed 41.7% binaural hearing loss and deducted a pro rata proportion for the period between 2016 and 2019. In response to a specific question from Ventia’s solicitors, Dr Payten said that about one third of the impairment or 7% was due to employment with Ventia.
Ventia disputed the claim on the basis that Mr Mawson had not given notice of injury or made a claim within the time allowed by the 1998 Act.
The parties entered into consent orders dated 4 July 2023 and amended on 19 July 2023 with the assistance of a member of the Personal Injury Commission. The orders were amended to rely on a deemed date of injury of 31 December 2015. Unfortunately no consent findings were sought or made to reflect the agreement made by the parties as to why that date was chosen. The reason may be based on the notice under s 78 of the 1998 Act issued on 16 September 2022 in which Ventia said that the deemed date of injury must be the last date on which Mr Mawson was employed by Ventia before a claim was made on
11 March 2021. As a result of those consent orders, the claim was referred to the Medical Assessor.
The Medical Assessor obtained a history of the employment in 2021 and said that Ventia was Mr Mawson’s last noisy employer. He included the loss at all frequencies from 500 Hz to 4,000 Hz in his assessment. He assessed binaural hearing loss of 40.3%, representing 20% WPI. He did not make any deduction from that assessment.

PRELIMINARY REVIEW

We conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the Procedural Direction PIC7.
As a result of that preliminary review, we determined that it was not necessary for Mr Mawson to undergo a further medical examination because there is enough information in the file to deal with the matter on the papers.

EVIDENCE

We have all the documents that were sent to the Medical Assessor for the original medical assessment and have taken them into account in making this determination.
The parts of the MAC that are relevant to the appeal are set out, where relevant, in the body of this decision.

SUBMISSIONS

Both parties made written submissions. They are not repeated in full, but we have considered them.
Ventia explained a small part of the background with respect to the deemed date of injury in its submissions. It said that at a preliminary conference on 3 July 2023 the parties agreed that the deemed date of injury was 11 March 2021. For reasons which are not disclosed, the parties then agreed to amend the deemed date to 31 December 2015. Ventia noted that the Medical Assessor did not record a history of Mr Mawson returning to work for Ventia on about 14 October 2022.
In summary, Ventia said it was “uncontroversial” that there must be an adjustment of the WPI to preclude Mr Mawson being compensated for hearing loss after the deemed date of injury, that proposition being “established” in Schofield v Abigroup Limited[1] (Schofield) in which Fullerton J held that in assessing the degree of permanent impairment which occurred at the deemed date of injury, it was necessary to make an adjustment for the injury which was the result of employment after that date.
[1] [2016] NSWSC 954.
Ventia also submitted that the Medical Assessor was in error in failing to attribute any of the WPI to pre-existing or non-related loss which “in the context of the established facts” that Mr Mawson had engaged in noisy employment after the deemed date of injury and also outside NSW before the deemed date of injury. Ventia said that Mr Mawson could not recast his claim to include the period after the date of the claim for compensation in 2021 because s 17 of the 1987 Act deemed the injury to have occurred on the last date he worked for Ventia before that date and the parties agreed that was the deemed date of injury. Any claim in respect of the subsequent employment with Ventia must be a new claim, referring to Sukkar v Adonis Electronics Pty Ltd (Sukkar).[2] It submitted that the Medical Assessor’s assessment contravened the proper application of s 17 and allowed the worker to be compensated in respect of the loss which should be the subject of a further claim.
[2] [2014] NSWCA 459.
Ventia said that Mr Mawson’s statement showed that he had hearing tests in 2018 and was told by Freedom Hearing that he had insufficient loss to make a claim. He was retested in 2020. On that basis, Ventia submitted that the hearing loss Mr Mawson suffers now could not be the result of employment before 31 December 2015.
With respect to noisy employment outside NSW before 31 December 2015, Ventia said that the Medical Assessor applied incorrect criteria in failing to make a deduction under s 323 of the 1998 Act because the legislation does not have extraterritorial operation, referring to Garling J’s statement “about the presentation of the worker’s case” in Pereira v Siemens Ltd:[3]
“First, an underlying assumption has been made that the deeming provisions of Section 17 of the 1987 Act apply with respect to loss of hearing which may have occurred in employment outside NSW, which employment is not subject to the provisions of the 1987 Act.”
[3] [2015] NSWSC 1133 at [97].
Ventia said that a deduction should have been made to reflect Mr Mawson’s noise exposure in South Australia in 1998 and 1999 and in respect of his employment by Thames Gas Company in the United Kingdom in 1975 and 1976. Ventia did not make any submissions about the extent of the deduction.
In reply, Mr Mawson submitted that there was no basis to make a deduction in respect of subsequent employment, citing a statement by Walsh J in Bain v Commissioner for Railways[4] which “all members of the High Court either accepted or did not dissent from” in Commissioner for Railways v Bain[5] (Bain). Mr Mawson noted that the operation of s 17 was explained in A & G Engineering Pty Ltd v Civitarese[6] (Civitarese) and Russo v World Services and Construction[7] (Russo). The effect of those decisions is that there is no need to prove causation because it is irrelevant to the operation of s 17. There is also no need to prove that employment was the main contributing factor to the injury.[8]
[4] (1963) 81 WN (Pt1).
[5] (1965) 112 CLR 246.
[6] (1996) 14 NSWCCR 158.
[7] [1979] 1 NSWLR 330.
[8] Fairfield City Council v Deguara (2019) NSWWCCPD 1.
Mr Mawson said that the effect of those cases was that any attempt to apportion losses the loss between that occurring before the deemed date and that occurring after the date was an irrelevant inquiry into when the loss was actually caused and that s 17 operated to deem all the loss of hearing assessed as having occurred on 31 December 2015.
Mr Mawson said that Ventia’s submissions confused the question of whether there was a previous injury or pre-existing condition with the question of whether it contributed to the impairment for the purpose of s 323.

FINDINGS AND REASONS

The procedures on appeal are contained in s 328 of the 1998 Act. The appeal is by way of review of the original medical assessment but the review is limited to the grounds of appeal on which the appeal is made.
In Campbelltown City Council v Vegan[9] the Court of Appeal held that an Appeal Panel is obliged to give reasons. Where there are disputes of fact it may be necessary to refer to evidence or other material on which findings are based, but the extent to which this is necessary will vary from case to case. Where more than one conclusion is open, it will be necessary to explain why one conclusion is preferred. On the other hand, the reasons need not be extensive or provide a detailed explanation of the criteria applied by the medical professionals in reaching a professional judgement.
[9] [2006] NSWCA 284.
In New South Wales Police Force v Registrar of the Workers Compensation Commission of New South Wales[10] Davies J considered that the form of the words used in s 328(2) of the 1998 Act “the grounds of appeal on which the appeal is made” was intended to convey that the appeal is confined to the errors identified by a party in its submissions. We have considered only those grounds raised by the parties.
[10] [2013] NSWSC 1792.
Section 17 of the 1987 Act provides:
“17 Loss of hearing—special provisions
(cf former s 7 (4B), (4BB))
(1) If an injury is a loss, or further loss, of hearing which is of such a nature as to be caused by a gradual process, the following provisions have effect—
(a)for the purposes of this Act, the injury shall be deemed to have happened—
(i)where the worker was, at the time when he or she gave notice of the injury, employed in an employment to the nature of which the injury was due—at the time when the notice was given, or
(ii)where the worker was not so employed at the time when he or she gave notice of the injury—on the last day on which the worker was employed in an employment to the nature of which the injury was due before he or she gave the notice,
(b)the provisions of section 61 of the 1998 Act shall apply to or in respect of the injury as if the words ‘as soon as practicable after the injury happened and before the worker has voluntarily left the employment in which the worker was at the time of the injury’ were omitted therefrom,
(c)compensation is payable by—
(i)where the worker was employed by an employer in an employment to the nature of which the injury was due at the time he or she gave notice of the injury—that employer, or
(ii)where the worker was not so employed—the last employer by whom the worker was employed in an employment to the nature of which the injury was due before he or she gave the notice,
…”

The MAC

The Medical Assessor determined that Ventia was Mr Mawson’s last noisy employer. He obtained a history of his employment, noting:
“From 1975-1976, he was employed by Thames Gas Company in England as a Maintenance Fitter & Gas Welder and was exposed once again to loud noise.”
The Medical Assessor undertook an audiogram and determined that the asymmetry he observed was not significant. He said:
“After consideration of the long duration of noise exposure, the cumulative noise emission levels to which Mr Mawson has been exposed and the shape of the audiogram, I would consider that all frequencies in both ears have been damaged by unacceptable noise levels and I have used all frequencies in the calculations for noise induced hearing loss.”
The Medical Assessor said that there was no deductible proportion under s 323 but did not provide reasons. He disagreed with a deduction made by Dr Payten, qualified for Ventia, for a period of employment in Victoria on a factual basis. He determined that hearing aids were reasonably necessary.

Schofield

Because of the reliance placed on Schofield by Ventia, it is appropriate to consider the decision in some detail. It has been followed by some Medical Appeal Panels[11] and distinguished in others.[12] Those decisions which have followed it have done so on the basis that the panel was bound by Supreme Court authority, without engaging in detail with the reasoning. The decision should be read in light of its unusual facts - there was a gap of about 30 years between the deemed date of injury in New South Wales and the claim and the worker was employed in noisy employment for 20 years after he left New South Wales.
[11] For example, Cuskelly v New England Milk Industries Pty Limited [2020] NSWWCCMA 2 and Miller v Tom Condon Stone Masonry [2023] NSWPICMP 578.
[12] For example, Curran v Linfox Armaguard [2021] NSWPICMP 76.
Schofield concerned an application for judicial review of the decision by a delegate of the Registrar of the Workers Compensation Commission to decline to refer a matter to a Medical Appeal Panel. In 2010, Mr Schofield claimed permanent impairment compensation for binaural hearing loss suffered between 1957 and 1981. He left New South Wales in 1981 and worked in noisy employment interstate until 2001. An Approved Medical Specialist (AMS) assessed 9.8% binaural hearing loss and apportioned 51.2% to employment outside the state, with the result that no compensation was payable under s 66.
Mr Schofield argued that his hearing loss was deemed to have occurred “in one blow” so that it was immaterial what employment the loss could be traced to. He argued that it was sufficient that there was exposure in New South Wales to which the nature of the injury is due for s 17 of the 1987 Act to be invoked, permitting him to claim compensation for the full extent of the assessed hearing loss.
Mr Schofield’s employer argued that the AMS was required by s 319(c) of the 1998 Act to assess the degree of permanent impairment “as a result of the injury” which occurred in 1981 and therefore was obliged to factor into his assessment the loss attributable to employment outside the state after that date.
Section 319 is the section of the 1998 Act in which medical dispute is defined:
“319 Definitions
In this Act—
medical dispute means a dispute between a claimant and the person on whom a claim is made about any of the following matters or a question about any of the following matters in connection with a claim—
…
(c) the degree of permanent impairment of the worker as a result of an injury,
…”
Mr Schofield’s employer noted the operation of s 17 and accepted that the decisions which interpret it “were decided consistent with the long settled and beneficial purpose of ensuring that a worker who is injured by gradual process… is compensated by fixing liability to pay compensation upon the last employer in New South Wales.” It argued that decisions such as Civitarese were concerned to ensure that the worker was not left without compensation but that those cases should not be construed so as to entitle a worker to recover compensation from the last employer in New South Wales where there was clear evidence that part of it occurred outside the jurisdiction and after the date on which the injury is deemed to have occurred.
Fullerton J noted that Russo concerned a worker who worked in New South Wales between 1967 and 1972 then for the Commonwealth from 1972 to 1975. He was compensated for the aggravation of an injury by the Commonwealth then made a claim in New South Wales. His employer sought to argue that the Commonwealth was the last noisy employer but the Court of Appeal held that s 7(4) of the Workers Compensation Act 1926 (the 1926 Act) did not include the Commonwealth as an employer. Fullerton J observed:
“No issue arose as to whether the compensable injury should be assessed to include any part of the injury that resulted from the worker’s employment with the Commonwealth (for which he had been compensated) after his employment with the respondent.”
Her Honour observed that Civitarese also concerned the identity of the employer liable to pay compensation but said that the question she was required to consider:
“… is the extent of its liability for that injury where there is unchallenged evidence apportioning the degree of permanent impairment resulting from the injury the plaintiff sustained in New South Wales as at the date that injury was deemed to have occurred in New South Wales and in ‘one blow’. That question of apportionment did not arise in A & G Engineering or in Russo.”

Fullerton J did not consider that Lennon v TNT Australia Pty Ltd[13] or Sukkar offered any guidance on the question of apportionment and said that the issue did not arise in Pereira v Siemens Limited[14] (Pereira).
[13] [2013] NSWCA 77; 84 NSWLR 161.
[14] [2015] NSWSC 1133.
The decision did not refer to any legislative basis for the apportionment, nor, apparently were any submissions made which went beyond s 319(c) of the 1998 Act. Her Honour concluded:
“I regard the construction of s 319(c) of the 1998 Act as it applies in the context of the operation of s 17 of the 1987 Act for which the first defendant contends as the correct construction. That is, that as the plaintiff’s last employer in New South Wales at the date of the Notice of Injury, the first defendant was liable under s 17(1)(c)(ii) for the injury to the plaintiff’s hearing that had occurred ‘in one blow’ as at the deemed date of injury by a gradual process predating that date. Accordingly, in assessing the degree of permanent impairment as a result of that injury, the Approved Medical Specialist was required to make an appropriate adjustment for injury that was the result of the plaintiff’s employment after the deemed date in the course of employment outside the jurisdiction.”

Caselaw not considered in Schofield

Rico Pty Ltd v Roads and Traffic Authority (Rico) is an important authority not referred to in Schofield. It concerned the construction of transitional provisions of the 1987 Act for the purpose of a claim under the former s 67. Sheller JA said: [15]
“The legislative scheme for awards of compensation for boilermaker’s deafness proceeds on the following assumptions or fictions:
1.     The condition known as ‘boilermaker’s deafness’ is deemed to be a loss of hearing which is of such a nature as to be caused by a gradual process (s 17(2)).
2.     A loss of hearing which is of such a nature as to be caused by a gradual process is an injury (s 17(1)).
3.     In the language of Barwick CJ, in Commissioner for Railways v Bain the injury is taken to have happened ‘as it were, in one blow’. If the worker was, at the time when he or she gave notice of the injury, employed in an employment to the nature of which the injury was due, the injury is deemed to have happened at the time when the notice of the injury was given; if the worker was not so employed, when he or she gave notice of the injury, the injury is deemed to have happened on the last day on which the worker was employed in such employment, before he or she gave the notice (s 17(1)(a)”
[15] (1992) 28 NSWLR 679, 689-690.
His Honour said:
“Section 17 deems the injury here suffered to have happened at a particular time for the purposes of the Act. The time the injury actually happened is irrelevant. Clause 2 of Pt 6 limits the application of s 67 to injuries received after a particular time. The question for decision is whether cl 2 refers to the point of time at which the injuries were actually received or to the deemed or notional point of time prescribed by s 17.
To choose the actual point of time is to depart from the result of an historical development in workers compensation legislation in New South Wales designed, in the case of progressive slow growing industrial or occupational diseases or injuries, to relieve the worker from the daunting forensic task of proving when they occurred and, if they were employment related, by which relevant employer compensation therefor is payable. In the case of loss of hearing caused by a gradual process, s 17 achieves this design by providing that the loss is an injury which happened at a particular arbitrary point of time, making compensation payable upon demonstration that the worker was employed by an employer in an employment to the nature of which the injury was due and fixing a particular employer with liability, though leaving that employer a right to recover contribution from another or other employers in appropriate circumstances.”
The contribution to which his Honour referred is that provided for in the limited circumstances in the latter part of s 17, not relevant in this case.
In Blayney Shire Council v Lobley[16] (Lobley) the Court of Appeal explained that s 17 was not concerned with true causation but deemed the loss to have happened at one time. It required the last noisy employer to pay compensation whether or not that employment actually caused the loss.
[16] (1995) 12 NSWCCR 52.
In OneSteel Ltd v Devine[17] (Devine) Roche DP considered Rico and said:
“There are many cases where the employer who made only a minimal contribution to the actual hearing loss suffered pays all or most of the compensation awarded. However, there will be many other situations where the same employer will pay no compensation for the hearing loss caused by its employment. That is the nature of a scheme based on assumptions and fictions. It is therefore incorrect to submit that the statutory scheme requires an employer to pay compensation only for those injuries or losses suffered by the worker in that employer’s employment.”

Consideration
[17] [2012] NSWWCCPD 52 at [48].

Section 323 of the 1998 Act allows for a deduction for the proportion of the impairment that is due to a previous injury, condition or abnormality. There is no corresponding provision in respect of a subsequent injury.
We accept that a decision of the Supreme Court is usually binding on us, while the decision of another appeal panel is not, however we decline to follow Schofield because it does not follow the principles established by appellate decisions over many years. It turned on s 319(c) of the 1998 Act, which is a definition section in respect of a medical dispute, permitting the dispute to be determined by a Medical Assessor. It provides that a medical dispute includes a dispute about the degree of impairment as a result of an injury. That can only mean an injury as defined in the legislation and, for a noise-induced hearing loss, an injury as defined in s 17, based on the series of fictions and assumptions in that section. The last noisy employer at the deemed date of injury is liable to pay compensation calculated on the basis of the assessment by the Medical Assessor. So long as the employment has the tendencies, incidents and characteristics so as to cause hearing loss, questions of actual causation are not relevant. The definition in s 319(c) does not determine the deemed date of injury.
An examiner can only assess the hearing loss suffered as at the date of the audiogram he or she undertakes. There is no medical basis to determine what the loss was at an earlier time and if any deduction is to be made, it can only be done mathematically.
The loss assessed by the Medical Assessor as at the deemed date of injury was 40.3% which converts to WPI of 20%. No issue was raised with respect to that assessment and Ventia is responsible to compensate Mr Mawson in respect of it, subject to a deduction under s 323.
Since 2015 Mr Mawson has worked for a total of two years – periods of nine months in 2016, six months in 2018 and six months in 2019 for UGL Operations in Victoria and a period of three months for Ventia in 2021. Because the rate of hearing loss is greater at the commencement of noisy employment, it is unlikely that those periods have contributed substantially to the hearing loss he suffers.
Ventia made two other arguments which do not change the outcome. It is correct to say, on the authority of Sukkar, that a claim in respect of Mr Mawson’s employment after the deemed date of injury on 31 December 2015 might give rise to a further claim. In practice, the further loss cannot be assessed because the loss can only be measured at the date of the audiogram. The argument does not assist in the determination of the appeal. The facts in Sukkar were also different to those here. One of the questions considered was essentially whether claims for compensation for hearing loss made in 1996 and 2012 could be aggregated so as to exceed the threshold for the award of compensation in s 66(1) of the 1987 Act. Mr Sukkar had been assessed after the first date of injury and he was paid compensation on the basis of a complying agreement. He made a further claim supported by an assessment that did not meet the threshold for compensation. In that context, the Court of Appeal determined that the scope of the injury was determined by s 17 of the 1987 Act applied so that s 66(1A) prevented a further claim in respect of the loss which was the subject of a prior claim. Section 66(1A) did not prevent a claim for further loss of hearing, being a new injury with a new deemed date. The result in that case was that the worker’s 2012 claim did not meet the relevant threshold for compensation and thus for referral to an AMS.
Ventia also relied on Mr Mawson’s statement to argue that he did not have sufficient hearing loss in 2018 to make a claim and therefore the loss he now suffers could not be a result of employment as at 31 December 2015. He said:
“I had my hearing tested by Freedom Hearing in 2018. After the test I was told that I had hearing loss but it wasn't enough to make a claim. I was very surprised by this because my family and friends were constantly telling me I was deaf.”
There is no other evidence about that hearing test. The statement is hearsay. Even if that was the opinion of the audiologist in 2018, it has no evidentiary value because there was no agreement between the parties evidenced by a complying agreement and no assessment by an AMS. We do not accept Ventia’s argument that because Mr Mawson had ceased employment three years before 2018 any hearing loss now suffered could not be due to employment before 2015. It is not consistent with the authorities described above and Ventia’s acceptance that Mr Mawson was employed in noisy employment.

Section 323

The legislation does not have extraterritorial operation.[18] Section 68B(4) of the 1987 Act prohibits a deduction under s 323 for the proportion of the impairment which is due to employment by an employer to whom s 17 applies, except to the extent that compensation has been paid or is payable. Employment outside New South Wales is not previous relevant employment so that noise-induced hearing loss suffered overseas before working for an employer in New South Wales may give rise to a s 323 deduction.
[18] Mynott v Barnard [1939] HCA 13; 62 CLR 68.
The worker in Pereira had worked for 17 years in Pakistan before working for 32 years in New South Wales. The AMS calculated the percentage of Mr Pereira’s working life referrable to the period in Pakistan and deducted that percentage of his impairment of binaural hearing loss. The approach was confirmed by a medical appeal panel.
On judicial review in the Supreme Court, Garling J said in that the assessment under s 323 “is one which must be made based on fact, not assumptions or hypotheses”.[19] His Honour set out the operation of s 17, referring to Lobley and the operation of s 323 and considered assumptions made by the appeal panel including that, because the worker was exposed to a workplace in which noise was generated, he must during the period of that exposure have suffered a pre-existing injury. His Honour said:[20]
“The difficulty with such a conclusion is that there was simply no factual material which was sufficient to enable such a conclusion to be drawn. Whilst there was factual material available which described some of the work which took place in Pakistan, nowhere was there any evidence which would enable a conclusion to be drawn that the level of noise to which the plaintiff was exposed in Pakistan, was of a nature which would have, by a gradual process, resulted in a loss of hearing. Nowhere was there any material which allowed the Appeal Panel or the AMS, to conclude that the plaintiff had been exposed to an unacceptable noise level for a sufficient length of time, and of the kind of noise level which, on the probabilities, would have resulted in an injury.”
[19] At [81], referring to Elcheikh v Diamond Formwork (NSW) Pty Ltd (In Liq) [2013] NSWSC 365 at [89]; Matthew Hall Pty Ltd v Smart [2000] NSWCA 284 at [33]; Ryder v Sundance Bakehouse [2015] NSWSC 526 at [40].
[20] At [100].
Referring to the one-tenth deduction provided for in s 323(2), his Honour went on:[21]
“The application of this rule of thumb deduction does not constitute fulfillment, in a hearing loss case, of this required element. As a matter of logic, the present extent of the plaintiff’s hearing loss may have been caused entirely by the plaintiff’s employment in NSW over the 32 year period. There is nothing about his present degree of whole person impairment which would, of itself and without more, enable a contrary conclusion. There was no material for example, which enabled a finding that the level of impairment from loss of hearing for the plaintiff, could not all have arisen during the 32 year period of employment in NSW.
However, the Appeal Panel and the AMS have simply assumed that by application of the straight line method of attribution of deafness, there must have been a pre-existing injury, and the degree of impairment from which the plaintiff suffers must have been contributed to by all of the pre-existing noise exposure.
This is nothing more than assumption or speculation. The conclusion is not sufficient to satisfy the obligation under s 323 of the 1998 Act to be satisfied that a pre-existing injury has contributed to the present impairment.”
[21] At [104]-[107].
Mr Mawson was employed in the United Kingdom between 1975 and 1976 at the beginning of his working life as a maintenance fitter. The Medical Assessor recorded that he was exposed to loud noise in that job.
Dr Fagan, qualified for Mr Mawson, initially included that period with subsequent employment in New South Wales and said that the whole of the employment from 1971 to 1998 was noisy. In his first and second reports he did not take a history of employment outside Australia, though said in his third report that the employment with Thames Gas Co was not noisy. The inconsistency between those reports makes the history difficult to accept.
Dr Payten recorded that the only employment outside New South Wales was in Victoria.
We accept that the history obtained by the Medical Assessor that the period of employment in the United Kingdom as a maintenance fitter and gas welder was noisy. Mr Mawson did not resile from that history on the appeal. There is therefore a basis to consider a deduction under s 323 and the comment by the Medical Assessor means that the case is different to Pereira.
It is medically accepted that the hearing loss due to occupational noise exposure progresses more rapidly in the first several years of exposure than in later years. We accept that the impact of a period of one year of noisy employent when Mr Mawson was in his early twenties was relevant to the loss he now suffers and that it is probable that it exceeds an assessment made on a pro rata basis. The extent of the impact is difficult to determine so that the assumption of one-tenth in s 323(2) applies.
Mr Mawson also worked for a period of two years in South Australia in 1998 and 1999. He said in his statement that he was employed by Transfield Services and exposed to noise. We understand from paragraph 34(d) of Ventia’s submissions that Transfield was a previous name of Ventia. While Mr Mawson said that he was employed in South Australia at that time, he subsequently worked interstate when working for Transfield. The mere fact of working in South Australia is an inadequate reason to determine that he was not employed in New South Wales. In the absence of evidence as to where Mr Mawson was employed and because the period was more than 20 years into his working life, we decline to make an additional deduction.
For these reasons, we have determined that the MAC issued on 29 August 2023 should be revoked, and a new MAC should be issued. The new certificate is attached to this statement of reasons.

WORKERS COMPENSATION DIVISION

APPEAL PANEL

MEDICAL ASSESSMENT CERTIFICATE

Injuries received after 1 January 2002

Matter number:	W3930/23
Applicant:	Greg Mawson
Respondent:	Ventia Australia Pty Ltd

This Certificate is issued pursuant to s 328(5) of the Workplace Injury Management and Workers Compensation Act1998.

The Appeal Panel revokes the Medical Assessment Certificate of Medical Assessor Kenneth Howison and issues this new Medical Assessment Certificate as to the matters set out in the table below:

Table - calculation of whole person impairment (WPI) for industrial deafness as set out in the Table immediately below in accordance with Chapter 9 of the Guidelines for the Evaluation of Permanent Impairment and 1988 NAL Tables:-

Notional date of injury	Frequency Hz	Left dB HL Air Bone	Right dB HL Air Bone	Total % BHI	Occupational % BHI
31/12/2015	500	40	35	5.1	5.1
1000	45	35	6.9	6.9
1500	50	60	8.4	8.4
2000	60	55	8.5	8.5
3000	65	60	6.4	6.4
4000	65	70	6.8	6.8
TOTAL % BHI: 41.7%
Less Pre-existing non-related loss (s323): 41.7% - 4.17% = 37.5
Less Presbyacusis correction: 4.4
Add % of severe tinnitus: 3.0
Adjusted total % BHI: 36.1%
Resultant total BHI of 36.1% = 18% whole person impairment (Table 9.1)

The above assessment is made in accordance with the SIRA NSW Guidelines for the Evaluation of Permanent Impairment for injuries received after 1 January 2002.

[2024] NSWPICMP 42

30 January 2024