A major point of failure in modern commercial contracting is the belief that hiring a specialized subcontractor completely transfers all operational safety risk to that downstream provider. WHS executives frequently assume that if a subcontractor signs a contract and provides a safe work method statement (SWMS), the principal contractor’s duty to monitor the day-to-day execution of the work is minimized.
This defensive shield has been dismantled by a significant common law judgment from the Supreme Court of the ACT. The landmark decision in Brekalo v Sommerauer & Ors [2017] ACTSC demonstrates that a principal contractor maintains a continuous obligation to supervise site safety, finding that passive oversight of heavy machinery exclusion zones can result in severe shared liability following a catastrophic field incident.
The Breakdown of the Exclusion Zone
The incident occurred on a commercial construction site managed by the principal contractor, Huon Contractors Pty Ltd. A subcontractor was engaged to operate a heavy excavator within an active work area. During operations, the excavator operator became distracted by his personal mobile phone, answering a call while actively manipulating the heavy vehicle’s controls.
Unaware of his immediate surroundings due to the distraction, the operator did not see a pedestrian worker—an employee of a concrete subcontractor, Kuna Contractors—approach the machine to discuss coordinates for a delivery. The operator accidentally dropped the heavy stabilizing blade onto the worker’s foot, causing severe, permanent physical trauma.
The subsequent investigation exposed a critical gap in the principal contractor’s risk management system: passive enforcement. While Huon Contractors had established a clear traffic management plan on paper, site practices had degraded. In fact, site supervisors frequently undermined their own mobile phone restrictions by calling the operator directly on his device throughout the shift to adjust task parameters. Furthermore, the site relied heavily on an informal “eye contact” rule between pedestrians and operators, which proved to be an entirely insufficient substitute for a monitored physical barrier.
The Symmetrical Allocation of Fault
The total damages for the injury were settled at $830,000, with an additional $95,000 in agreed legal costs. While principal contractors often expect downstream providers to absorb the entire financial burden of an operational error, the ACT Supreme Court applied a rigorous three-way split of the liability based on concurrent negligence.
The court apportioned 40% of the fault directly to the heavy machinery operator for operational negligence and failing to pay proper attention while handling heavy plant. Kuna Contractors, the worker’s employer, was apportioned 20% of the liability for failing to properly ensure their staff maintained safe physical separation from active machinery.
Crucially, Huon Contractors was held liable for 40% of the damages bill. The court ruled that as the principal contractor with overall management control of the site, Huon maintained a non-delegable obligation to oversee the working environment, monitor subcontractor behavioral patterns, and actively enforce compliance. Simply pointing to the subcontractor’s immediate mistake or mobile phone use did not absolve the principal of its systemic failure to step in and secure the workspace.
| Deficiency Vector | Administrative Illusion | Forensically Audited Reality |
|---|---|---|
| Zone Management | Accepting a signed SWMS as proof that an exclusion perimeter will be respected by all field personnel. | Deploying physical barricades, locking gates, or installing automated proximity sensors on plant assets. |
| Contractor Vetting | Treating the initial collection of insurance policies and equipment tickets as complete risk discharge. | Executing regular, documented field inspections to verify real-time compliance with site protocols. |
| Device Governance | Relying on a generic, passive handbook policy banning personal phone use inside heavy machinery cabins. | Enforcing zero-tolerance contractual penalties and halting communication loops that use unauthorized devices. |
Practical Lessons for Field Safety Leaders
To ensure construction and civil projects are protected from shared common law liability, principal contractor oversight must transition from administrative tracking to active site verification:
- Enforce Hard-Barricaded Exclusion Zones: When heavy plant operates in high-traffic or multi-employer zones, physical fencing or locked barricades must be deployed. Where mobile tasks make physical separation impossible, the use of passive spotters or smart proximity-sensing technology must be mandated.
- Establish Clear Communication Protocols: Principal contractors must eliminate the practice of supervisors calling heavy machinery operators on mobile phones while they are running equipment. All operational communication must be routed through two-way radio networks with mandatory stop-work rules for operators answering calls.
- Document Active Supervisory Interventions: Site managers must maintain auditable daily logs demonstrating that they are actively inspecting subcontractor tasks, auditing exclusion perimeters, and halting operations whenever an unauthorized workaround is identified.
Source Material & Further Reading
- Primary Judgment: Brekalo v Sommerauer & Ors [2017] ACTSC (Supreme Court of the Australian Capital Territory common law determination on shared tortious liability and mobile phone distraction).
- Statutory Reference: Work Health and Safety Act 2011 (ACT), Section 19 (Primary duty of care).
- Common Law Framework: Civil Law (Wrongs) Act 2002 (ACT), Chapter 4 (Negligence standards and the proportional apportionment of liability).
