Workplace Safety and Accident Prevention
What the exam tests
Accident causation, prevention tools and the standard safety performance metrics.
Key concepts
- Unsafe acts and unsafe conditions both precede accidents, and most events involve several failures.
- Heinrich domino theory: social environment, fault of person, unsafe act or condition, accident, injury; removing the middle domino prevents injury.
- Swiss cheese model (Reason): hazards pass through aligned holes in defences; latent management failures matter as much as active front-line failures.
- Prevention tools: inspections, toolbox talks, JSA, permit to work for hot work and confined space entry, lockout/tagout, housekeeping, machine guarding, manual handling assessment, management of change.
- Investigation: secure the scene, gather evidence, interview, use 5 Whys or fishbone to reach root causes (usually management-system failures), then assign tracked corrective actions.
- Metrics: LTIFR = (lost-time injuries x 1,000,000) / hours worked; TRIR often uses 200,000 (100 employees x 40 hours x 50 weeks). Never mix the constants.
Worked example
A site records 3 lost-time injuries in 480,000 hours worked. LTIFR = 3 x 1,000,000 / 480,000 = 6.25 lost-time injuries per million hours. Reasoning: always state the constant you used; with 200,000 the answer would be 1.25, and mixing bases makes benchmarking meaningless.
Traps
- Reporting the worker was careless as the root cause; this stops the investigation at the symptom.
- Counting near misses as lost-time injuries, which inflates the rate.
- Using 200,000 one year and 1,000,000 the next.
- Corrective actions with no owner or due date.