Safety Hierarchy of Controls: A Brief Overview

December 1, 2022 By

The safety hierarchy of controls is a workplace safety guide developed by The National Institute for Occupational Safety and Health (NIOSH). The guide provides a five-step process to help safety professionals reduce the risk of harm to workers.

These five steps include:

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

When applied, they can provide a robust safety methodology applicable to any workplace environment. However, implementation starts by first understanding what a hazard is and how it applies to the workplace.

What is a workplace hazard?

A hazard is something that can potentially cause harm. Although the terms hazard and risk are used interchangeably, they are not the same. A risk is the degree of possibility that harm can occur. As such, different hazards have different risk profiles. That is, each hazard has a different degree of possibly causing harm. Defining workplace hazards is the first step to mitigating the risk of harm. A health and safety hierarchy of risk control is useful in both defining hazards and mitigating them.

Steps to Implement the Safety Hierarchy of Controls

Health and safety hierarchy of controls are organized in a step format – starting from the most effective (elimination) to the least effective (PPE). Each step cascades to the next, allowing the application of safety measures based on the viability of each step.



NIOSH considers elimination as the most effective way to prevent harm. If a hazard is eliminated from a workplace, it cannot cause harm. While effective, elimination is also the most difficult to implement because, in many cases, it is impossible to separate work from hazards.


The simplest way to implement the elimination safety control step is to identify workplace hazards and remove them. Elimination does not only mean removal from your business premises. It can also mean isolating hazards from workers, so workers have no contact with the hazards.



If removing a hazard is not an option, substitution may be a possibility. In this step, NIOSH recommends finding safer alternatives to existing hazards. For example, safe cutting tools in place of dangerously sharp blades lowers the risk on a cutting activity. Alternatives could also mean substituting dangerous materials for safer ones or substituting dangerous work practices for safer ones. Substitution helps to strike compromises in cases where elimination is not an option.


Implementing substitution safety controls involves identifying hazards that cannot be eliminated but are replaceable with a safer alternative. For example, if workers interact with dangerous chemicals, you can substitute this hazard through machine automation or the use of safer chemicals.

Engineering Control


Engineering controls use engineered measures to isolate hazards. In cases where elimination and substitution are not possible, a company can choose to build structures like barriers to separate hazards from workers. Engineering controls function as stopgap measures, offering short-term benefits for a long-term problem. But sometimes, they’re the best you can do.


Implementing engineering controls involves building some form of protective structure. It can be a barrier, a safety ladder, or a vent hood. The primary function of the structure is to separate workers from the hazard. Since the hazard is not eliminated or substituted, it still poses a risk even with engineering safety controls in place.

Administrative Control


Administrative controls shift focus from the hazard to managing the human element involved in risk. For any hazard to cause harm, a worker must complete an action. The method of completion determines the level of risk the worker faces from the hazard. Administrative safety control puts measures in place that ensure that all actions taken focus on reducing risk.

Training and awareness are the focus of administrative safety controls. Ensuring workers understand hazards and associated risks is an essential step in enforcing workplace safety. Training may include safety training or technical training, with the latter intended to minimize operation-based mistakes.

Personal Protective Equipment (PPE)


PPE can be considered the last line of measures in a hierarchy of controls in occupational health and safety. This step intends to protect workers in scenarios where a company has not or cannot implement the other steps fully. PPE includes safety apparel and equipment like dust masks, coveralls, gloves, HAZMAT suits, and others.


PPE implementation means providing safety gear and equipment optimized for existing hazards. If workers work in a lab, for example, full-body suits can protect from lab hazards. PPE is considered the least effective safety step because safety gear and equipment can fail, leaving the worker fully exposed to the hazard.

Realizing Prevention through Design (PtD)

As the saying goes, an ounce of prevention is worth a pound of cure. PtD is a NIOSH initiative pushing for design-level safety measures. Such measures prevent or “design out” hazards before work begins. When applied successfully, PtD removes the need to apply any of the safety controls above. However, this only applies to new operations which are still in the design phase. For existing operations, the safety hierarchy of controls remains the best framework for preventing workplace harm.

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