Risk Assessment and Hazard Control
Core concepts
Risk assessment is the systematic evaluation of hazards to decide what controls are needed. Know the standard steps: identify hazards, determine who may be harmed and how, evaluate likelihood and severity, decide controls, record findings, and review. Common methods include qualitative matrices, risk scoring, and task-based assessment. Understand residual risk (what remains after controls) and ALARP (as low as reasonably practicable).
Hazard control
Apply the hierarchy of controls. Engineering controls change the environment; administrative controls change behaviour or procedures; PPE protects the individual. Controls should be proportionate to the risk, reliable, and verified. Consider human factors: poorly designed controls invite workarounds.
Traps in questions
- Confusing likelihood with severity, or scoring a risk without considering exposure frequency.
- Assuming controls eliminate risk rather than reduce it.
- Choosing administrative controls when engineering is feasible.
- Forgetting to review the assessment after a change.
Rule of thumb
Score risk as likelihood x severity, then ask whether the control is feasible and effective. If a control depends on perfect human behaviour, it is weaker than one that removes the hazard.
Worked example
A machine has a rotating shaft. Likelihood of contact is moderate; severity is severe. A guard (engineering) reduces both; a warning sign (administrative) does not. The best answer is the guard, followed by training and verification that the guard stays in place.