Hazard Identification, Risk Assessment, and Control: Hierarchy of Controls
Hazard versus risk
A hazard is a source of potential harm; risk is the likelihood and severity of harm from that hazard. Hazard identification and risk assessment (HIRA) means identifying hazards, assessing risk, prioritizing, controlling, and monitoring. Use inspections, job hazard analysis, checklists, HAZOP for processes, incident data, and worker reports. Cover routine and non-routine tasks.
Hierarchy of controls
Apply controls in this order: elimination, substitution, engineering controls, administrative controls, and PPE. PPE is the last line, not the first. Consider effectiveness, feasibility, and residual risk. Involve workers, because they know how the task is actually done. Reassess risk after controls.
Risk assessment
Use a risk matrix of likelihood and severity. Prioritize high-risk tasks. Consider chemical, physical, biological, ergonomic, and psychosocial hazards. Record the assessment and review it when processes, equipment, or materials change.
Worked example
Welding fume in a small fabrication shop. Elimination is not feasible; substitution means low-fume electrodes; engineering means local exhaust ventilation; administrative means rotation and training; PPE means a suitable respirator. Monitor exposure and reassess residual risk. Choosing only a respirator ignores higher-order controls.
Traps that cost marks
Jumping to PPE, relying on “common sense,” ignoring residual risk, and omitting non-routine tasks such as maintenance and cleanup are common errors. Do not treat risk assessment as a one-time form.