(b) whether there was a causal connection between the two accidents.
8 The primary judge was also required to apply various parts of the Workers Compensation Act 1987 (NSW) (the "WC Act"), s 151Z dealing with circumstances of recovery against both the employer, Macquarie, and the "stranger" (to use the terminology of the section heading to s 151Z), Birdon Marine.
9 It will be necessary, in due course, in order to deal fully with the above issues, to appreciate how the matter was approached by the parties at the hearing below. Before seeking to understand how the primary judge expressed himself in dealing with these issues, it is convenient to set out the relevant parts of s 151Z.
10 Subsections 151Z(1) and (2) are in the following terms:
"(1) If the injury for which compensation is payable under this Act was caused under circumstances creating a liability in some person other than the worker's employer to pay damages in respect of the injury, the following provisions have effect:
(a) the worker may take proceedings both against that person to recover damages and against any person liable to pay compensation under this Act for payment of that compensation, but is not entitled to retain both damages and compensation,
(b) if the worker recovers firstly compensation and secondly those damages, the worker is liable to repay out of those damages the amount of compensation which a person has paid in respect of the worker's injury under this Act, and the worker is not entitled to any further compensation,
(c) if the worker firstly recovers those damages the worker is not entitled to recover compensation under this Act,
(d) if the worker has recovered compensation under this Act, the person by whom the compensation was paid is entitled to be indemnified by the person so liable to pay those damages (being an indemnity limited to the amount of those damages),
(e) if any payment is made under the indemnity and, at the time of the payment, the worker has not obtained judgment for damages against the person paying under the indemnity, the payment is, to the extent of its amount, a defence to proceedings by the worker against that person for damages,
(e1) if any payment is made under the indemnity and, at the time of the payment, the worker has obtained judgment for damages against the person paying under the indemnity (but judgment has not been satisfied), the payment, to the extent of its amount, satisfies the judgment,
(f) all questions relating to matters arising under this section are, in default of agreement, to be settled by action or, with the consent of the parties, by the Commission.
(2) If, in respect of an injury to a worker for which compensation is payable under this Act:
(a) the worker takes or is entitled to take proceedings independently of this Act to recover damages from a person other than the worker's employer, and
(b) the worker also takes or is entitled to take proceedings independently of this Act to recover damages from that employer,
the following provisions have effect:
(c) the damages that may be recovered from the person by the worker in proceedings referred to in paragraph (a) are to be reduced by the amount by which the contribution which the person would (but for this Part) be entitled to recover from the employer as a joint tortfeasor or otherwise exceeds the amount of the contribution recoverable,
(d) the amount of the contribution that the person is entitled to recover from the employer as a joint tortfeasor or otherwise is to be determined as if the whole of the damages were assessed in accordance with provisions of Division 3 as to the award of damages,
(e) if the worker does not take proceedings against that employer or does not accept satisfaction of the judgment against that employer, subsection (1) applies as if the worker had not been entitled to recover damages from that employer, except that:
(i) if the compensation paid by that employer exceeds the amount of the contribution that could be recovered from that employer as a joint tortfeasor or otherwise - the indemnity referred to in subsection (1) (d) is for the amount of the excess only, and
(ii) if the compensation paid by that employer does not exceed the amount of that contribution - subsection (1) (d) does not apply and the employer has, to the extent of the compensation so paid, a defence to an action for such a contribution."
11 Two aspects of these provisions arose on the facts here, both before the primary judge and on the appeal. As will be seen from what follows, one of those aspects was approached on appeal in a different way than it was below.
12 The first aspect concerned the reduction in any judgment against the third party (Birdon Marine) by reference to the responsibility of the employer (Macquarie). None of Mr Jepp's doctors assessed him to have a whole person impairment ("WPI") above 15 per cent. By reason of the WC Act, s 151H(1), this meant that no damages would be awarded to Mr Jepp in any common law action against Macquarie, as employer. Also, in these circumstances by reason of the WC Act, s 151Z(2)(c) and (d) Birdon Marine was not able to recover against Macquarie on any cross-claim, though its liability in damages at the suit of Mr Jepp would be reduced by the full amount of any contribution which, but for the WC Act, Part 5, it would have been entitled to recover from Macquarie. So, if the primary judge apportioned responsibility to Macquarie as X per cent, because Mr Jepp's WPI was less than 15 per cent neither Mr Jepp (because of s 151H(1)) nor Birdon Marine (because of s 151Z(2)(d)) was entitled to recover against Macquarie, but Birdon Marine was entitled to have its liability reduced by X per cent (s 151Z (2) (c)).
13 Secondly, the question of the operation of s 151Z(1) arose. The introductory words or chapeau of s 151Z and the terms of s 151Z(1)(d) have been the subject of authoritative interpretation in this Court. In Kornjaca v Steel Mains Pty Ltd [1974] 1 NSWLR 343 in dealing with words in the Worker's Compensation Act 1926 (NSW), s 64(1)(b) equivalent to the WC Act, s 151Z(1)(c), Glass JA said at 347:
"It is necessary … that the injury occurred under circumstances which created a liability in damages to the worker. It does not seem possible to regard a pre-existing liability, which became more extensive on the happening of the [second] injury, as one which was then created."
14 The same construction was applied in Hood Constructions Pty Ltd v Nicholas (1987) 9 NSWLR 60 at 69, Dudley v Condell Park Carrying Co Pty Ltd (1988) 4 NSWCCR 58 at 65, Kempsey District Hospital v Thackham (1995) 36 NSWLR 492 and Mancini v Thompson [2002] NSWCA 38. As Handley JA pointed out in Thackham at 508, the High Court in Manser v Spry [1994] HCA 50; 181 CLR 428; 68 ALJR 869 at 433; 871 construed comparable South Australian legislation in similar fashion.
15 The consequence of this construction and of the requirement that there be no double compensation is that where a third party tortfeasor is liable for a first injury and compensation is payable under the WC Act for a later injury which is an extension of the injury first caused, s 151Z(1) is not the relevant regime to eliminate any double recovery. Rather, the worker is entitled to a common law judgment against the third party, but one reduced by the value of the compensation payable under the WC Act: Adams v Ascot Iron Foundry Pty Ltd (1968) 72 SR (NSW) 120, Vanramer Pty Ltd v Higgins (1991) 24 NSWLR 661 and Thackham.
16 Thus, here, if the first injury was caused by the negligence of both Birdon Marine and Macquarie, Birdon Marine would be entitled to a percentage reduction in the judgment against it in favour of Mr Jepp referable to Macquarie's responsibility, because Macquarie was not liable to Birdon Marine on the cross-claim, Mr Jepp having less than 15 per cent WPI. Any workers compensation payments referable to the first injury would be dealt with in the regimes provided for by s 151Z(1). So, under s 151Z(1)(b), such workers compensation payments referable to the first injury that had been paid would have to be refunded out of the judgment and no further such sums would be payable.
17 If the second injury was caused by Birdon Marine's negligence which led immediately to the first injury, any workers compensation paid or payable consequent upon the second injury would not be dealt with by the regime under s 151Z(1) for the reasons referred to above. Rather, the value of any future entitlements to workers compensation from the second injury would have to be assessed at the hearing and deducted from the judgment. Likewise, amounts of workers compensation referable to the second injury that had been paid prior to the common law judgment would be deducted from the judgment (rather than included in the judgment and reimbursed as they would be if s 151Z(1) applied).
18 Thus, in summary: