Question 7 of 7: Accident Case Analysis — Spray-Gun Amputation
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Notes on this paper
National Exams — May 2015 — 11-CS-2 Engineering in Society: Health and Safety. Closed book; approved calculator permitted. Any five of the seven questions constitute a complete paper; all questions are of equal value. Answers are written in point form but fully, as instructed. Complete answers to all seven questions follow.
Immediate cause — the employee cleaned the clogged nozzle while the gun was still pressurized/energized, with the thumb in front of the tip; when the clog cleared, the gun discharged its stored pressure into the thumb (a high-pressure discharge/injection injury), causing the laceration and amputation. Unsafe act: servicing a live tool; unsafe condition: no means of relieving the pressure or locking the trigger.
Root/contributing causes: no safe procedure to depressurize/lock out before servicing; inadequate training on the injection hazard and correct clearing method; gun lacked safeguards (trigger lock/guard, automatic pressure relief); clogging from poor filtration/maintenance created the need to intervene.
(ii) Corrective Actions
Safe procedure (LOTO/depressurization) — shut off, disconnect and relieve pressure before any cleaning; never point at the body.
Engineering — guns with trigger locks/guards and automatic pressure relief; improve fluid filtration to reduce clogging.
Training — high-pressure injection hazards (appear minor but are surgical emergencies) and correct unclogging.
PPE and maintenance — gloves/eye protection; regular servicing schedule.
(iii) Follow-Up
Investigate and document (root-cause analysis); report the serious injury to the regulator as required (in B.C., WorkSafeBC under the Workers Compensation Act), with the joint health and safety committee involved in the investigation.
Implement corrective actions; update the written safe-work procedure; retrain all affected employees.
Verify effectiveness by inspection/audit; ensure medical care and return-to-work; share lessons across similar operations.
