Hierarchy of Control Measures

Effective hazard control methods reduce workplace injuries and illness and generally make the workplace safer. The types of control measures used vary widely depending on circumstance or need, and are rarely simple. Not all control methods offer equal protection, and choosing the wrong method can have serious consequences.

The hierarchy of hazard control is an easy-to-use graph designed to provide guidance when choosing control methods. Used by multiple organizations, including OSHA and the CDC, the hierarchy of hazard control resembles an upside-down “food chain” pyramid. The higher up the inverted pyramid, the more effective the control methods.

Types of Control Measures

In order of effectiveness, the control methods recommended by the hierarchy of hazard control are:

• Elimination
• Substitution
• Engineering controls
• Administrative controls
• Personal Protective Equipment (PPE)

1. Elimination

Elimination is the most effective hazard control method as the hazard is physically removed from the workplace. Eliminating tasks performed in high areas would eliminate falls, for instance, while automating equipment could remove the need for employees to perform tasks in hazardous zones.

While effective, eliminating hazards is not always possible. Many pieces of electrical equipment carry the risk of arc flash, for instance, but remain vital to production. If so, the other types of control measures on the hierarchy offer solutions.

2. Substitution

The second control method on the hierarchy of hazard controls, substitution replaces hazardous equipment, materials, or processes with safer alternatives. For instance, carcinogenic or caustic chemicals might be replaced with other chemicals. Less noisy equipment could replace machinery that damages hearing. 

Care must be taken to ensure the hazard control methods introduced as substitutions do not introduce other hazards to the workplace. All risks associated with the new equipment or process must be considered.

3. Engineering Controls

Engineering controls describe strategies to prevent contact between hazards and employees. Moving dangerous equipment to an isolated room, erecting physical barriers to enclose the hazard, or locking hazardous chemicals in secure locations are all examples of engineering controls. Removing airborne contaminants from the workplace using effective ventilation systems also qualifies as an engineering control.

Engineering controls are considered more effective than administrative controls and PPE because they physically distance employees from hazards. The upfront costs of engineering controls can be high, but reduce future costs associated with the hazard.

4. Administrative Controls

Administrative hazard control methods reduce the risk of injury through employee training, procedural changes, and installing signs and warning labels. Clearly labeling hazardous chemicals, using lockout/tagout equipment, providing electrical safety training to employees, and labeling arc flash hazards are all administrative hazard control methods. Administrative controls do not remove the threat, seeking instead to educate employees on the risk. As such, they are not as effective as the first three types of control measures.

5. PPE

PPE is considered the least effective solution on the hierarchy of hazard control, which surprises many people because PPE is one of the most highly visible hazard control methods.

PPE efficiency is only effective if the wearer is trained in the proper use of protective gear, understands the limitation of PPE, and actually wears PPE (hearing protection is a good example of PPE that is often ignored by employees, who find it interferes with the communication). PPE can also be damaged either with routine use or if contact is made with the hazard, reducing its ability to protect the wearer.

Using Multiple Hazard Control Methods

The hierarchy of hazard control does not require you to choose only one type of control measure. Often multiple control methods are required. For instance, enclosing a dangerous piece of machinery may protect most of your employees, but your maintenance crew would need to access it. To keep them safe, a combination of administrative controls and PPE may be required over and above the engineering controls.

Building a culture of safety complements any safety methods a workforce has in place. Safety Orientation training helps employees develop the awareness they need to prevent accidents, use PPE properly, and identify hazards as they arise. Together with the hierarchy of hazard control, a safety-conscious workforce greatly reduces the financial and human costs associated with on-the-job injuries.