Implementing controls is essential in hazard mitigation and limiting potential incidents and injuries. The hierarchy of controls is a system that can be used to determine the most effective and feasible control solutions.
The hierarchy of controls contains five levels ranging from most to least effective: elimination, substitution, engineering, administrative, and personal protective equipment (PPE). Employers should try to implement the most effective control first. If the most effective control is unfeasible, then employers should try to implement the next control until they discover the best option. Following this hierarchy generally leads to safer systems and risk reduction.
Elimination is the most effective type of control because it does not just reduce the risk of the hazard, it completely removes the hazard from the workplace. If we can eliminate the hazard, we should, but many times the hazard is essential to the work performed.
Example
Problem: A piece of equipment is missing a guard.
Solution: Remove the piece of equipment from operation.
Substitution is the next best option. This control requires a product or machine to be replaced with a similar but safer option. To implement a substitution control, the hazard must first be identified, and a replacement must be available.
Example
Problem: A piece of equipment is missing a guard.
Solution: Replace the inadequate piece of equipment with a different piece of equipment that does not need a guard or has one in place.
Engineering controls are the third tier of the hierarchy. Engineering controls are designed to isolate a person from ever encountering a hazard, such as a physical barrier or an exhaust ventilation system. These controls should be considered after ruling out the possibility of eliminating or substituting the hazard.
Example
Problem: A piece of equipment is missing a guard.
Solution: Install a physical barrier/system to isolate the hazard from employees.
Administrative controls are where policies and procedures are born. These types of controls tend to be the cheapest but not the most effective. Since these controls cannot physically remove/isolate a hazard, they often rely on employee understanding and compliance of the control. These controls include standard operating procedures, training, signage, job rotations, etc.
Example
Problem: A piece of equipment is missing a guard.
Solution: Create a policy and post signage so employees avoid equipment.*
PPE is the last line of defense. Unfortunately, PPE does not actually control hazards, it simply limits the potential severity if an accident should happen. PPE is sometimes mistaken by employees as the best line of defense but should be used if all other controls fail. The focus should always be on implementing the top tiers of the control hierarchy, so we don’t have to rely on PPE.
Example
Problem: A piece of equipment is missing a guard.
Solution: Have employees wear gloves and face shields.*
*The “piece of equipment missing a guard” scenario is strictly for example purposes only. If a piece of equipment is defective or missing a safety item, it should be removed from service immediately until properly guarded.
