A Guide to the Hierarchy of Controls

What is a Hazard?

When looking at dictionaries, hazard is often associated with the terms, “danger, peril, threat, and risk.” That’s why it’s understandable that many people use the terms hazard and risk interchangeably. A hazard can be an object, a material, a substance, a condition, a process, or even a behavior. Some examples are: temperature extremes, broken cutting tools that can cause injury or major accidents, and loose electricity wires that may cause shock or electrocution. For more information, check out the Occupational Safety and Health (OSH) answers from the Canadian Centre for Occupational Health and Safety (CCOHS) on identifying the different kinds of hazards.

According to CCOHS, hazard identification should be done when:

• During design and implementation
• Designing a new process or procedure
• Purchasing and installing new machinery
• Before tasks are done
• Checking equipment or following processes
• Reviewing surroundings before each shift
• While tasks are being done
• There are changes, abnormal conditions, or sudden emissions
• During inspections

What is Risk?

Risk is the likelihood or probability that a hazard will cause harm or adverse health effects, such as bodily injuries and diseases, on an individual if exposed to a hazard. The level of risk associated with an event can be determined by the likelihood of  the event occurring and its potential consequences— or damage—it could cause.

Factors that influence the likelihood of risk as given by CCOHS are:

• the nature of the exposure—example: extreme temperature exposure
• how the person is exposed—example: inhaling poisonous chemicals
• the severity of the effect—example: skin cancer or skin irritation

What are Control Measures?

There are different levels of hazard and risk. Some cause catastrophic consequences, like a loose power line or a car crash, while others are relatively minor, like a papercut. These hazards should also be addressed with different levels of solution.

Control measures are simply the protective steps made to remove the hazard or risk, or at least minimize it to the lowest level possible. They are put in place as part of a control of work system in order to minimize the probability or consequences of an incident. As a significant part of risk assessments performed by organizations, control measures set out the actions that must be followed to protect employees and other people in the area.  

For most workplaces, a systematized approach to controlling hazards and risks is needed. When deciding on what actions to implement, you should use the principles of control. Control measures often refer to the hierarchy of control measures—a systematized hazard prevention strategy.

Hierarchy of Controls

The systematized control measure approach used by companies of all kinds, sizes, and industries to protect people in the workplace is called the hierarchy of controls. The “Hierarchy” is a basic principle that is widely-accepted by health and safety professionals choosing the best ways to reduce the risk of any hazard. The Occupational Safety and Health Administration (OSHA) and the National Safety Council (NSC) recommend adherence to this strategy to ensure safety in the work environment.

History of Hierarchy of Controls

Safety was mostly a matter of trial and error before the 1940s. At that time, the predominant methodology applied during the design and testing phase of experimental aircraft was called “fly-fix-fly.” It was a method wherein an aircraft makes a circuit and if it breaks, they fix it and fly it all over again until the root of the issue is discovered and resolved. This method was unreliable and dangerous as it caused injuries and other fatalities. A better system was needed to replace it.

It was in 1950 when the NSC began introducing a safety system known as the “hierarchy of controls,” in which the goal is to control exposures to hazards and risks as a way of protecting workers. The concept of the hierarchy dates back to the creation of OSHA by the Occupational Safety and Health Act (OSH Act) of 1970 and of the National Institute for Occupational Safety and Health (NIOSH). NIOSH launched a national initiative called Prevention through Design (PtD) in 2017.

Prevention through Design (PtD)

Prevention through design (PtD), commonly called “safety by design” in Europe, is the process of “designing out” with the concept of safety or reduction of occupational hazards in mind and with an emphasis on employees’ health and safety throughout the life cycle of materials and processes.

5 Levels of Hierarchy in Eliminating Hazards and Risks

The control measures in the hierarchy are placed in order of their effectiveness. These stages can be considered as lines of defense.

1. Elimination: Removing the hazard or risk entirely
2. Substitution: Replacing the hazard with a safer alternative
3. Engineering Controls: Replacing equipment, including a mechanical device, or process, or changing the work environment to separate workers from a hazard
4. Administrative Controls: Developing procedures and processes for working safely under anticipated conditions
5. Personal Protective Equipment (PPE): Equipping workers with protective gears designed to reduce risk and severity of injuries

Why Use the Hierarchy of Controls?

Since its introduction in the 1950s, the hierarchy of controls has remained central to workplace safety laws and regulations.

• NIOSH recognizes the hierarchy as an important system in protecting workers from harm, danger, and injuries in the workplace, and includes it as a strategy in the national PtD initiative. It has the mandate to assure “every man and woman in the Nation safe and healthful working conditions and to preserve our human resources.”
• OSHA mentions the hierarchy as a recommended practice for safety and health programs.
• The NFPA includes the hierarchy of controls in the 70E: Standard for Electrical Safety in the Workplace as part of their process after risk assessments to avoid injuries and fatalities due to shock, electrocution, arc flash, and arc blast.
• The NSC highlights the hierarchy of controls as a safety tool to its members and uses it in workshops and as a helpful reference on safety to its readers.

The hierarchy of controls is undeniably linked to workplace safety. Using the hierarchy is not only for safety—it’s one of the best ways employers can protect their workers and control risks more effectively rather than simply letting incidents happen. The hierarchy also serves as a template for organizations on how to minimize hazards and risks for preventing incidents and fatalities. 

Using the Hierarchy of Controls

The idea behind the step-by-step approach to reducing hazards and controlling risks is that those measures at the top of the graphic are potentially more effective and protective, but the hardest to implement (e.g., eliminating a virus that caused a pandemic) than those at the bottom. The controls are ranked from the most protective to the least protective and also least effective.

1. Elimination

Elimination is the removal of the hazard completely and is the highest level of protection and the most effective control measure.

How to use: The source of hazard can be taken out of the environment or workplace entirely.

Example: Remove chemicals that could cause a severe irritation to the skin.

2. Substitution

Substitution is the replacement of hazards with safer alternatives.

How to use: If eliminating the source of the hazard is not possible, the next level of defense is to substitute or replace it with a less hazardous source—thus minimizing the level of injuries or adverse effects on a person’s health.

Example: Replace solvent-based paint with water-based paint. 

3. Engineering Controls

Engineering controls involve replacing equipment and processes or changing the work environment to separate or isolate workers from exposure to the hazard.

How to use: Given a source of hazard that can’t be removed from the environment or can’t be replaced with a safer option, management and employers may implement the next level in the funnel—reducing the risks through engineering changes or changes in the process or building.

Example:  Use remote controls to operate machines.

4. Administrative Controls

Administrative controls  refer to any training, practice, policy, or design changes that reduces an individual’s exposure to a hazard. This is a low level of protection and less reliable control. 

How to use: If the implementation of an engineered solution is impossible, then the implementation of administrative controls is the next line of defense. This involves the use of warning labels, changes to corporate policy, and conducting workshops or training sessions.

Example: Develop guidelines on how to use the machines and tools safely.

5. Personal Protective Equipment (PPE)

PPE refers to anything workers use or wear to reduce risks to their health and safety. This is the last line of defense in the hierarchy, the lowest level of protection, and the least reliable control. 

How to use: Workers should wear protective gear such as ear plugs, goggles, face masks, respirators, gloves, aprons, safety harnesses, bodysuits, and others.

Example: Provide respirators to protect workers from inhaling toxic gases, fumes, and pollutants. 

Managements or employers may consider using various controls in addressing hazards and minimizing risks. 

Reduce Hazards and Risks Efficiently With SafetyCulture (formerly iAuditor) 

Identify, assess, and mitigate potential hazards and minimize the levels of potential risk with SafetyCulture. Available as a mobile app, this tool will help you conduct risk assessments more efficiently by converting paper checklists into easy-to-use digital templates that can be used to generate reports.

SafetyCulture is one of the best tools for risk assessment and is used by industries in manufacturing, construction, hospitality, retail, and more. Below are more ways SafetyCulture helps in adhering to the hierarchy of controls:

• Create a safety checklist that can be customized according to your requirements.
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• Develop safety systems in compliance with duties under the OHS Act.
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