Question 7 of 7: Accident Case Analysis — Spray-Gun Amputation

Question 7: Accident Case Analysis — Spray-Gun Amputation (20 marks: 6/6/8)

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) Cause of the Accident

• Immediate cause — the employee attempted to clean the clogged nozzle while the spray gun was still pressurized/energized (not de-energized or depressurized). The gun discharged high-pressure fluid into the thumb (a high-pressure injection injury), causing the laceration and subsequent amputation.
• Contributing/root causes (multiple-factor):
  • Procedure/management — no safe procedure for clearing a clog; the tool was not required to be depressurized/locked out and relieved of pressure before servicing.
  • Training — the worker was unaware of the severe danger of high-pressure injection and of the correct clearing method.
  • Equipment — spray gun lacked adequate safeguards (e.g., trigger guard/lock, automatic pressure relief, or a design that prevents discharge when serviced).
  • Task/media — clogging (poor maintenance/filtration of the preventative) created the need to intervene.

(ii) Corrective Actions Required

• Safe procedure (LOTO/depressurization) — require that the gun be shut off, disconnected from air/fluid supply, and pressure relieved before any cleaning or unclogging; never point at any body part.
• Engineering — provide guns with trigger locks/guards and automatic pressure relief; improve fluid filtration/viscosity control to reduce clogging; consider design that cannot discharge during servicing.
• Training — instruct workers on high-pressure injection hazards (which look minor but are surgical emergencies) and on the correct, safe unclogging method.
• PPE — appropriate gloves/eye protection as a supplementary measure.
• Maintenance — regular cleaning/servicing schedule to prevent clogs.

(iii) Follow-Up Action

• Investigate and document the accident fully (root-cause analysis); report as legally required.
• Implement the corrective actions and update the written safe-work procedure.
• Retrain all affected employees on the new procedure and the injection hazard.
• Verify effectiveness — inspect/audit to confirm the controls are in place and followed; monitor for recurrence.
• Medical/return-to-work — ensure the injured worker receives care and a suitable return-to-work plan.
• Share lessons learned across similar operations to prevent the same injury elsewhere.