2.6: Hierarchy of Controls

Select controls according to a hierarchy that emphasizes engineering solutions (including elimination or substitution) first, followed by safe work practices, administrative controls, and finally PPE. Avoid selecting controls that may directly or indirectly introduce new hazards. Examples include exhausting contaminated air into occupied workspaces or using hearing protection that make it difficult to hear backup alarms. Use a combination of control options when no single method fully protects workers.

A system for selecting and implementing the most effective control solutions for workplace hazards that includes:

· Elimination

· Substitution

· Engineering controls

· Administrative controls

· Personal protective equipment

This is known as the “hierarchy of controls” because they should be considered in the order presented. Controls at the top of the hierarchy are potentially more effective and more protective than those lower in the hierarchy.

Elimination makes sure the hazard no longer exists. Examples: ending the use of hazardous material, doing work at ground level rather than at heights, and stopping the use of noisy processes. Substitution means changing out a material or process to reduce the hazard. Examples: switching to a less hazardous material, switching to a process that uses less force, speed, temperature, or electrical current. Engineering controls reduce exposure by preventing hazards from coming into contact with workers. They still allow workers to do their jobs, though. Examples: noise enclosures, local exhaust ventilation, guardrail system, machine guards, interlocks, and lift equipment. Administrative controls change the way work is done or give workers more information by providing workers with relevant procedures, training, or warnings. They are often used with high-level controls. They include: procedures, such as equipment inspections, planned preventive maintenance, checklists, lockout/tagout/tryout, infection prevention and control practices, changing work schedules, pre- and post-task reviews, and rotation of workers; training on topics such as hazard communication, permit-required confined space entry, lockout/tagout/tryout, and safe work procedures; warnings such as signs, backup alarms, smoke detectors, computer messages, mirrors, horns, labels, and instructions. Personal protective equipment (PPE) includes clothing and devices to protect workers. PPE needs constant effort and attention (including proper use and training) from workers. Higher-level controls are not always feasible, and PPE might be needed in conjunction with other control measures. Examples: safety glasses, personal fall protection systems and related equipment, hardhats, respirators, hearing protection, and protective clothing.

Figure 2:1 Hierarchy of Controls. (Source: National Institute for Occupational Safety and Health, Public Domain).

To decide if control is feasible, you need to know how well it can protect workers and whether it can be implemented successfully. Consider whether it is:

• Right for the hazard

• Appropriate, given how likely injuries/illnesses are

• Consistent with employer policies, laws, and regulations

• Not too burdensome to workers

• Recognized as an appropriate practice in the industry

• Effective, reliable, and durable

• Readily available

• Cost-effective, short- and long-term

How can you use the hierarchy of controls?

First you will need to identify the hazard(s) you are trying to control with workers and their representatives’ participation.

Then, think about how you can block the path between the worker and the hazard. Brainstorm ways the hazard can be eliminated, substituted, engineered out, administratively controlled, or what PPE can be used with other controls. Ask yourself:

• What are the pros and cons of each method?

• Are the controls feasible in our workplace? Why or why not?

• Where do the feasible controls fall in the hierarchy?

Collaboratively choose the control(s) that falls highest on the hierarchy. If it takes time to implement, use one or more of the lower options you identified as interim controls until the permanent solution is in place. Remember that you may need a combination of control methods (such as engineering controls plus administrative controls) to provide the best level of protection. Be sure to comply with any workplace regulations which may require specific types of control for certain hazards.