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711 Introduction to Ergonomics
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711 Introduction to Ergonomics

Controlling Risk Factors

Analyzing jobs to identify factors lays the groundwork for developing ways to eliminate or reduce ergonomic risk factors for WMSDs.

hierarchy of controls

Hierarchy of Controls (HOC)

Traditionally, a prioritized "Hierarchy of Controls" (HOC) has been used to implement controls to protect workers. We encourage the use of the HOC as described within the ANSI/ASSP Z10, Occupational Health and Safety Management Systems, to control hazards. The six strategies are discussed below.

  1. Elimination: Completely eliminate the hazard so that it cannot cause 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.
  4. 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.
  5. Administrative/Work Practice Controls: Develop mandatory procedures and rules that reduce the possibility of exposure to hazards.
  6. Personal Protective Equipment (PPE): PPE helps to prevent contact with hazards and is used in conjunction with other controls.

Now let's look at each of the control strategies more closely.

Elimination and Substitution

Elimination and substitution, while most effective at reducing hazards, also tend to be the most difficult to implement in an existing process. If the process is still at the design or development stage, elimination and substitution of hazards may be inexpensive and simple to implement.

For an existing process, major changes in equipment and procedures may be required to eliminate or substitute for a hazard. For example:

  • Elimination - If you have to work in a space that requires poor work postures, you might eliminate the need to perform the work within that space.
  • Substitution - If you have to lift a heavy object, you might substitute the heavy object with an object of less weight.

Knowledge Check Choose the best answer for the question.

5-1. Using small boxes instead of larger, heavier boxes, for shipment is an example of which hazard control strategy?

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