Controlling Hazards
Industrial hygienists recognize several primary hazard control strategies to eliminate or reduce hazards and employee exposure.
The Hierarchy of Controls (HOC)
Industrial hygienists use the prioritized "Hierarchy of Controls" (HOC) to protect workers from hazardous substances. The HOC ranks control strategies from most effective to least effective, organized into two basic categories: Hazard Controls and Exposure Controls.
Hazard Controls
The first three HOC strategies focus on reducing the severity of exposure by directly eliminating or reducing the hazards themselves.
Elimination: Elimination completely removes the hazard from the workplace. It is the top priority for all safety professionals, including industrial hygienists. Examples include:
- Removing the need to use a hazardous substance in a production process
- Automating a manual task to eliminate worker exposure to harmful dusts or fumes
- Relocating a noisy machine away from work areas so employees are no longer exposed
- Discontinuing a dangerous process altogether and replacing it with a safer one
Substitution: Substitution is used when it is not feasible to eliminate the hazard entirely. This strategy reduces the severity of the hazard by replacing it with a safer alternative. Examples include:
- Replacing a toxic acid with a less toxic or non-toxic substance
- Using water-based paints instead of solvent-based paints to reduce vapor exposure
- Substituting lead solder with a lead-free alloy to reduce heavy metal hazards
- Replacing gasoline-powered equipment with electric-powered equipment to reduce noise and exhaust emissions
Although substitution reduces risks, some hazards may remain, so additional protection such as PPE may still be required.
Engineering Controls: Engineering controls remove or reduce hazards through design. This strategy involves designing or redesigning tools, equipment, machinery, or facilities so that hazardous materials are not required, or worker exposure is minimized. Examples include:
- Enclosing noisy machines in soundproof barriers or rooms
- Installing local exhaust ventilation systems, such as fume hoods, to capture contaminants at the source
- Adding machine guards to protect workers from moving parts
- Installing acoustic panels, mufflers, or silencers to reduce noise levels
- Redesigning workstations to minimize awkward postures and repetitive strain
- Using vibration-dampening mounts to reduce whole-body vibration from heavy equipment
Knowledge Check Choose the best answer for the question.
1-3. Industrial hygienists recognize several primary hazard control strategies to eliminate or reduce hazards and employee exposure. These basic control strategies are organized _____.
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