In February 2018, a worker was impaled by a starter bar after falling into a 1.8m deep excavation at a construction site. Early investigations indicate he was walking on a path close to the excavation when the ground slipped. This caused him to fall onto an uncapped starter bar which was protruding from a footing for a retaining wall at the bottom of the excavation. His injuries were not life threatening or permanent and investigations are continuing.
Preventing a similar incident
This incident highlights the falls risks associated with excavation and trench work. Control measures to keep workers away from the edge of an excavation or trench include:
- installing effective barriers or barricades
- providing clearly defined pedestrian detours.
Control measures specifically for excavation work include:
- inserting guard rails and toe boards into the ground next to the supported excavation side
- installing landing platforms or scaffold towers inside deep excavations
- providing alternative access and egress points to the excavation for emergency use
- backfilling the excavation as work progresses.
Control measures specifically for trenching work include:
- securing ladders to trench shields
- using trench box extensions or trench sheets longer than the trench depth
- installing guard rails or covers on trench shields.
This incident also highlights the risks presented by the exposed ends of reinforcement bars. Control measures include:
- using guardrails, screens or other means to separate workers from the exposed reinforcement bars
- using edge protection on scaffolds adjacent to exposed reinforcement bars regardless of height
- bending reinforcement bars from the top to prevent impalement
- covering exposed ends with boards or similar devices
- using rebar-caps (note this is a lower order control as they may not prevent impalement).
Since 2012 there have been 358 accepted workers’ compensation claims for injuries caused by pits and trenches, mainly in the construction industry. Of these, over 80 per cent involve slips, trips or falls and 45 per cent are for a serious injury with five days or more off work.
In the same period, we have issued 116 prohibition notices, 157 improvement notices, 2 electrical safety protection notices and 2 infringement notices for issues associated with excavations and trenches.