638 Preparing Workplaces for COVID-19

Exposure Control Strategies

The Hierarchy of Controls (HOC)

Occupational safety and health professionals use a framework called the "hierarchy of controls" (HOC) to select ways of controlling workplace hazards.

The idea behind this hierarchy is that the control methods at the top of the list are potentially more effective and protective than those at the bottom. Following the hierarchy normally leads to the implementation of inherently safer systems, ones where the risk of illness or injury has been substantially reduced.

Traditionally, the HOC has been used to implement feasible and effective exposure 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 to 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 it does 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. 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 contract with hazards and is used in conjunction with other controls.

According to OSHA, no one control measure may be totally effective against exposure. The most effective strategy to protect employees and the public is to use a combination of the hierarchy of control measures to best protect against exposure to infectious diseases. We will discuss each of the control measures in the next several sections.

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.

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