Simpson Design and Associates Pty Ltd v Industrial Court of New South Wales

Simpson Design and Associates Pty Ltd (the applicant) sought judicial review of a conviction in the Industrial Court of New South Wales. The applicant, the designer of a heavy gate that fell and caused a fatality at a workplace, had its defence of *novus actus interveniens* rejected by the Industrial Court. The core of the applicant's challenge was that the Industrial Court had applied the wrong test for causation, arguing that a design defect had been superseded by a subsequent negligent failure by a third party to rectify the defect.

The Court of Appeal was required to determine whether the Industrial Court erred in its application of the test for causation under section 11(1)(a) of the *Occupational Health and Safety Act 2000* (NSW). Specifically, the court had to consider whether the applicant's design defect remained a cause of the fatality, notwithstanding the alleged negligent failure of a third party to correct that defect, and whether the Industrial Court's decision was affected by a fundamental error.

The Court of Appeal dismissed the application, finding that the Industrial Court had correctly applied the principles of causation. The court reasoned that the defence of *novus actus interveniens* requires the intervening act to be so significant that it breaks the chain of causation. In this instance, the court held that the alleged negligence of the third party in failing to correct the design defect did not operate to break the chain of causation originating from the applicant's defective design. The design defect was found to be a continuing cause of the fatality. Consequently, the application was dismissed, and the applicant was ordered to pay the second respondent's costs.