Question 7 of 7: Case Study — Millwright's Fall from a Ladder While Adjusting a Flywheel Chain

Question 7: Case Study — Millwright's Fall from a Ladder While Adjusting a Flywheel Chain (20 marks: 7/7/6)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

(i) Determining the Causes of the Accident

Applying the unsafe-act/unsafe-condition framework, together with the design-deficiency list of Questions 2(iii) and 6(i), the accident has one immediate cause and several contributing root causes:

• Immediate/direct cause: the millwright over-reached from a ladder to make the flywheel-chain adjustment and lost his balance — an unsafe act, but one enabled by the conditions below rather than a simple isolated lapse.
• Contributing unsafe condition — inappropriate access method: a 20-foot ladder positioned so the worker had to "reach out" rather than work directly in front of the task indicates the ladder was not set up in line with the work, forcing an over-reach outside the safe working envelope (a stable stance keeps the body's centre of gravity between the ladder's rails).
• Contributing unsafe condition — no fall protection: nothing in the scenario indicates a fall-arrest/restraint system, guardrail, or platform was used for maintenance work at this height, despite the fall ultimately covering roughly 15 feet to the floor.
• Contributing unsafe condition — task performed without machine isolation: adjusting a flywheel chain places the millwright in direct proximity to a hazardous energy source; the awkward ladder-based reach suggests the press was not, or could not easily be, brought to a safe isolated state that would have allowed a properly positioned platform or a safer approach to the adjustment point.
• Contributing/aggravating condition — unguarded/hazardous fall path: the fall path passed across the shaft and into the conveyor before reaching the floor, meaning a fall from this working position (which any elevated maintenance task must treat as foreseeable) had no clear zone to land safely, and instead struck additional machinery, both increasing injury severity and causing the secondary property damage.
• Underlying/root cause: the absence of a formal, task-specific hazard assessment (job safety analysis) for this recurring elevated maintenance task, which would have identified the ladder-positioning, fall-protection, and machine-isolation gaps before work began, rather than leaving safe execution to the individual millwright's judgement in the moment.

(ii) Corrective Actions Required

1. Engineering — provide a proper work platform or scaffold for this recurring maintenance task, positioned directly at the adjustment point so the worker does not need to reach out beyond a safe stance.
2. Engineering/administrative — require fall-arrest/fall-restraint equipment (full-body harness and anchor point, per CSA Z259.10) for maintenance work above the applicable height threshold wherever a guardrail or platform is not provided.
3. Administrative — institute lockout/tagout for the flywheel/chain adjustment task, so the press drive is de-energized during the adjustment, removing both the hazardous-energy exposure and, where practical, the pressure that led to the awkward improvised access.
4. Administrative — require a job safety analysis (JSA) before this task, specifying safe access method, ladder set-up rules (correct angle, secured, maintained three points of contact, never reaching beyond the rails), and the isolation procedure.
5. Training — retrain millwright and maintenance staff on ladder safety, fall protection use, and the specific revised procedure for this task.
6. Layout review — where practical, relocate or guard the conveyor/press arrangement so that a foreseeable fall from the adjacent elevated maintenance position does not lead into unguarded moving equipment.

(iii) Follow-Up Action Required

• Regulatory incident reporting — report the compound fracture (a critical/serious injury) to the applicable provincial OHS regulator within the mandated timeframe, and to the Workers' Compensation Board.
• Formal incident investigation and documentation, using the root-cause analysis from part (i) as the basis for the corrective actions in part (ii).
• Extend the corrective actions to every similar press/flywheel maintenance task plant-wide, not just this specific press, since the underlying gap (no platform, no fall protection, no JSA) is a systemic condition that could exist wherever this maintenance task is performed.
• Verify and audit implementation at scheduled follow-up intervals (e.g. 30/90 days) to confirm the platform, fall-protection requirement, and lockout procedure have actually been put in place and are being followed, not just documented.
• Review through the joint health and safety committee, both to close the loop with worker representatives and to capture additional insight from maintenance crews performing this task regularly.
• Manage the injured worker's medical follow-up and return-to-work plan, coordinated with the compensation board, reflecting the severity of a compound fracture.
• Repair and inspect the damaged equipment (press shaft, belts, conveyor guard) for latent damage before returning it to service, and reinstate the conveyor guard before restart.
• Feed the incident into training program content as a case example for future ladder-safety and elevated-maintenance training, closing the loop from a real event back into prevention.