Hierarchy Of Controls
The hierarchy of controls is a structured, ranked system for selecting hazard controls, starting with the most effective (elimination) and progressing down to the least effective (PPE). Used by OSHA, WorkSafeBC, CSA, and ANSI, it systematically reduces workplace risk by prioritizing elimination, substitution, engineering controls, administrative controls, and PPE in that order.
On a manufacturing shop floor, the hierarchy is applied through risk assessment, control selection, implementation, and verification. For example, elimination removes hazardous steps (e.g., redesigning parts to avoid manual deburring). Substitution replaces hazards (e.g., using water-based cleaners instead of high-VOC solvents). Engineering controls isolate workers (e.g., machine guarding, local exhaust ventilation). Administrative controls change work practices (e.g., lockout/tagout procedures, job rotation). PPE is the last line of defense (e.g., respirators, hearing protection). WorkSafeBC requires minimizing risk to the lowest level practicable using engineering and administrative controls first, with PPE only for residual risk.
- Over-reliance on PPE and training as primary controls, ignoring higher-level controls like elimination or engineering, leading to non-compliance with 'lowest level practicable' provisions.
- Skipping elimination/substitution because they seem 'too hard,' without documenting reasonable alternatives, risking regulatory challenges for high-risk hazards.
- Treating engineering and administrative controls as one-off fixes without verification, leading to 'paper controls' that are not maintained or enforced, undermining effectiveness.
Is PPE ever acceptable as the primary control under OSHA or WorkSafeBC?
Only in limited circumstances where higher-level controls are demonstrably not practicable. OSHA and WorkSafeBC require PPE to be used after engineering and administrative controls have minimized risk, with documented justification and an exposure control plan.
How do CSA/ANSI standards refine the hierarchy of controls for machinery?
They add intermediate control types like awareness devices (lights, alarms) between engineering and administrative controls. For machine hazards, SafeDesk should distinguish engineering safeguards (guards, interlocks) from awareness devices and procedural controls (LOTO), tagging each to its hierarchy level.
How should 'practicability' be documented when higher-order controls are not used?
Through structured evaluation records referencing technical, operational, and economic factors. SafeDesk can include a 'Hierarchy evaluation' section listing elimination/substitution options and a decision log explaining why a combination of controls was selected, with residual risk acceptable per legal requirements.