Hierarchy of Controls
A Hierarchy of Controls provides a means of determining ways to implement systems or controls (from most effective to least effective) that protect workers from injuries, illnesses, and fatalities [National Institute for Occupational Safety and Health (NIOSH), 2021].
As identified in the graphic, the primary exposure control methods are hazard elimination or substitution by a less hazardous process or toxic substance. Workplaces should systematically implement exposure controls in the following order of effectiveness:
- Engineering Controls
- Administrative Controls
- Personal Protective Equipment (PPE)
In some cases, a combination of controls may be necessary (e.g., ventilated containment hoods and PPE when compounding chemotherapy drugs).