Hazard Control and Mitigation
Core concepts
Hazard control follows the hierarchy of controls: elimination, substitution, engineering controls, administrative controls, and PPE. Elimination removes the task or hazard; substitution replaces it with something less hazardous but can introduce new risks. Engineering controls-guarding, ventilation, isolation, interlocks, sound enclosures-work without relying on consistent worker behavior. Administrative controls include procedures, training, scheduling, and permits, but their effectiveness depends on compliance. PPE is the last line of defense and requires fit, maintenance, and correct use. Prevention through design applies the hierarchy earliest. Control selection should consider feasibility, durability, worker acceptance, and residual risk.
Traps
- Ranking a warning sign or training above an engineering fix.
- Assuming substitution is always safer; the replacement may be flammable, toxic, or incompatible.
- Treating PPE as a primary control when exposure can be engineered out.
- Forgetting maintenance and verification; a ventilation system that is not checked may be ineffective.
- Ignoring human factors that make a procedure hard to follow.
Worked example
A grinding station produces noise at 95 dBA. PPE (hearing protection) is the weakest option. Better: enclose the grinder, isolate it in a separate room, or automate the task; then reduce exposure time and post signs; finally provide hearing protection as residual protection. Rule of thumb: try to remove the hazard, then separate people from it, then change how people work, and use PPE last.