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662 HAZWOPER for General Site Workers III
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662 HAZWOPER for General Site Workers III

Hierarchy of Hazard Controls

Controlling exposures to occupational hazards is the fundamental method of protecting workers.

infographic hierarchy of controls

A prioritized Hierarchy of Controls (HOC) is traditionally used to put in place practical and effective ways to protect workers from exposure risks. The reason for using a "hierarchy" is that the strategies at the top are usually more effective and should be used before lower-level controls.

Hazard Controls

The top three strategies focus on eliminating, substituting, and engineering to control hazards at the source.

  1. Elimination: By eliminating the hazard you prevent exposure to the hazard, and prevent the possibility of an accident. This is your first priority, if feasible.
  2. Substitution: Replace materials, equipment, etc., with something that reduces the hazard to acceptable limits.
  3. Engineering controls: Design the environment, materials, tools, equipment and machines so that they do not present hazards.

Exposure Controls

The bottom three strategies focus on warnings, work practices, and PPE to control employee exposure to hazards.

  1. Warnings: Place OSHA signs (Danger, warning, caution, or safety instruction), audible alarms (klaxon, whistles, buzzers), or tactile warnings (vibration or fans) that alert employees about the presence of hazards.
  2. Work Practice Controls: Develop mandatory procedures and rules that reduce the possibility of exposure to hazards.
  3. Personal Protective Equipment (PPE): PPE helps to prevent contact with hazards and is used in conjunction with other controls.

Following this hierarchy normally leads to inherently safer systems, where the risk of illness or injury has been substantially reduced.

Interim Measures

Using a lower priority hazard control method over another higher priority control strategy may be appropriate for providing interim (temporary) protection until the hazard is abated permanently. If you can't eliminate the hazard entirely, the interim control measures will likely be a combination of control methods used together. OSHA believes that feasible interim measures are always available if higher-level control methods are not possible.

Knowledge Check Choose the best answer for the question.

1-9. According to the Hierarchy of Controls, what is usually the most effective strategy for controlling hazards?

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