A maintenance worker was fatally injured by the uncontrolled release of stored energy when working in the field on a belly plate (also known as a bottom guard or under guard) fitted to a bulldozer. No energy isolation mechanism was installed between the belly plate and the ground during the work.
Before removal of the belly plate’s fastening bolts, a “come-a-long” device (hand-operated ratchet lever hoist) had been attached to the flange on the right-hand (non-hinged) side of the plate. The worker then lay on the ground beneath the belly plate to access the fastening bolts on the left-hand side. When the fastening bolts were removed, that side of the belly plate fell and pinned the worker
to the ground. The plate and accumulated material weighed more than 400 kilograms and the worker was fatally injured.
Direct causes
- A stored energy hazard was left uncontrolled as no support was installed between the ground and the belly plate.
- The worker was beneath the belly plate when it fell.
Contributory causes
- The belly plate was not attached in accordance with the specifications of the original equipment manufacturer (OEM) — the hinge was not attached to the frame of the bulldozer and was later found to have pre-existing damage.
- The belly plate had non-OEM modifications, including a shackle welded to its flange and non-standard fasteners.
- The accumulation of material on the belly plate would have increased its weight and may have obscured critical components, such as the hinge point and missing fasteners.
- No job hazard analysis (JHA) or job safety analysis (JSA) was performed for this task.