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Correcting Hazards



In the last module, we examined the inspection and JHA processes to identify hazardous conditions and unsafe behaviors in the workplace. Once hazards have been identified, it's important that they be corrected immediately or as soon as possible.

Once hazardous conditions or unsafe behaviors are identified, it's important that the supervisor makes sure they are eliminated or reduced as soon as possible. To do this, one or a combination of the control strategies within the "Hierarchy of Controls" should be used.

In this module, we'll take a look at the Hierarchy of Controls and how they can effectively correct identified hazards. For more information on improving the safety management system, see Courses 704, Hazard Identification and Control and Course 716, Safety Management System Analysis.

The Hierarchy of Hazard Control Strategies

Image of Hierarchy of Controls in Construction
ANSI Z10/NIOSH Hierarchy of Controls.
(Click to Enlarge)

Controlling hazards and behaviors are the two basic strategies for protecting workers. Controlling hazards are more effective than controlling behaviors, and for good reason. If you can eliminate the hazard, you don't have to worry about exposure due to human behavior. Traditionally, a "Hierarchy of Controls" has been used as template for implementing feasible and effective controls.

ANSI Z10-2012, Occupational Health and Safety Management Systems, encourages employers to employ the following hierarchy of hazard controls:

Controlling hazards

  1. Elimination. "Design out" (eliminate) hazards and hazardous exposures.
  2. Substitution. Substitute less-hazardous materials, processes, operations, or equipment.
  3. Engineering controls. Design or redesign tools, equipment, and machinery to isolate process or equipment or contain the hazard.

Controlling behaviors

  1. Administrative/work practice controls. Job rotation, work scheduling, training, well-designed work methods, and organization are examples.
  2. Personal protective equipment. Includes but is not limited to safety glasses for eye protection; ear plugs for hearing protection; clothing such as safety shoes, gloves, and overalls; face shields for welders; fall harnesses; and respirators to prevent inhalation of hazardous substances.

As you can see, the control strategies first try to control hazards through elimination, substitution, or engineering. If the hazards can't be eliminated, replaced, or engineered, the hierarchy next attempts to control exposure to hazards through administrative methods and personal protective equipment. It's important to understand that:

  • Elimination, substitution, and engineering controls are independent: they do not rely on behavior to be effective.
  • Administrative, work practice, and PPE controls are dependent: they rely on compliant human behavior to be effective.

The "big idea" behind this hierarchy is that the control methods at the top of the list are potentially more effective and protective than those at the bottom. Following the hierarchy of controls leads to the implementation of inherently safer workplace environments, where the risk of illness or injury has been substantially reduced. Now, let's take a closer look at the hierarchy of control strategies.


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How can you eliminate the hazard of using a ladder when changing a light bulb?

Totally eliminating hazards, while most effective at reducing exposure to hazards, also tends to be the most difficult to implement in an existing process. This approach involves the initial design or redesign of tools, equipment, systems, production processes, and facilities in order to eliminate hazards associated with work.

If the machinery, equipment, or process is still at the design or development stage, eliminating hazards may be inexpensive and simple to implement. However, for an existing process, major changes be that can be very expensive. In the long term, even expensive changes that eliminate serious hazards may be cost effective.

Examples of elimination controls include:

  • Remove hazard from work zone, e.g., with exhaust ventilation to remove hazardous atmosphere.
  • Two-hand controls, safety switches, and hand guards to prevent "caught-in" and other accidents.
  • Ergonomically-designed tools to prevent cumulative trauma and other disorders.
  • Use of laser and enclosure to reduce excessive noise.
  • Replace the use of ladders with extension poles to change ceiling light bulbs to eliminate fall hazards.


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Replace toxic chemicals with non-toxic chemicals.

Substitution also focuses on doing something with the hazard, itself. It is simply replacing hazardous materials, processes, operations, machinery, and equipment with those that are less hazardous to reduce the severity of exposure. If you can't eliminate the hazard, then your thought should be, "how can I substitute this hazard with something less hazardous?"


  • Replacing defective tools, equipment, machinery.
  • Replacing a toxic chemical with a less/non toxic chemical.
  • Replacing hazardous materials such as abrasives.

Replacing hazardous chemicals, materials, tools, equipment or machinery may be expensive, but not as expensive as the average direct and indirect costs of a lost work time injury. According to the National Safety Council, is $34,000 and over $1 million to close a fatality claim.

Engineering Controls

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Good design isolates the hazard and protects employees.

Engineering controls use Prevention through Design (PtD) methods to prevent injuries and illnesses by "designing out" the hazards and risks. This approach involves the design or redesign of tools, equipment, systems, work processes, and facilities in order to reduce or eliminate the hazards associated with work.

PtD considers what is needed to protect workers throughout the life cycle process, machinery or and/ or process is being designed. The life cycle starts with concept development, and includes design, construction or manufacturing, operations, maintenance, and eventual disposal of whatever is being designed, which could be a facility, a material, or a piece of equipment.

It's worth saying again, well-designed engineering controls are highly effective in protecting workers and will typically be independent of worker interactions to provide this high level of protection: no matter what workers do, they won't be exposed to hazards.

Examples of effective engineering controls include:

  • Remove hazard from work zone, e.g., with exhaust ventilation.
  • Two-hand to operate machinery.
  • Use warning devices that stop operation if there is entry into hazard zone.
  • Safety switches, hand guards, barriers, and machine guards.
  • Redesign workstations and tools to best accommodate all workers.
  • Ergonomically-designed tools.
  • Automate processes to reduce worker exposure to repetitious movements.
  • Use of laser and enclosure to reduce excessive noise.
  • Enclosing a noisy machine
  • Presence-sensing devices
  • Place machine guards on a conveyor belt
  • Use a mobile scaffold
  • Use a laser cutting machine to cut down on noise

When considering engineering controls, you should think about the feasibility, costs, and ease of implementation of replacing or redesigning the equipment. OSHA expects your employer to consider these first three control strategies before employing administrative controls or personal protective equipment (PPE).

Administrative Controls

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Administrative controls use policies and procedures. These controls depend on worker compliance.

When exposure to the risk is not, or cannot, be minimized by other means, you should introduce administrative and work practice controls to reduce the risk. Administrative controls address how the work is to be performed, and direct people to work in a safe manner. They help establish effective processes and procedures in the workplace that reduce risk of injury and illness. A few examples include:

  • Limiting the amount of time someone is exposed to hazards.
  • Written operating procedures.
  • Safety and health policies, rules, and guidelines for employees.
  • Alarms, signs, and labels.
  • Use of the "Buddy system," especially in hazardous operations.
  • Training on safe work practices and procedures
  • Requiring two or more workers to lift heavy loads
  • Worker rotation to minimize the duration of exertion, repetitive motions, and awkward/uncomfortable positions.
  • Written operating procedures, work permits, and safe work practices
  • Procedures that ensure workers are using and maintaining pneumatic and power tools properly

Work practice controls. These controls also focus on the way workers do their jobs to reduce exposure to hazards. Work practice controls help to limit exposure by decreasing the following factors:

  • the frequency of exposure to the hazard,
  • the duration of the task that exposes the employee to the hazard, and
  • the number of employees exposed to the hazard.

Preventive Maintenance. The best way to prevent breakdowns or failures is to monitor and maintain your equipment regularly. Determine what hazards could occur if your equipment is not maintained properly and plan to detect failures before they occur.

Administrative and work practice controls used as the primary controls for protecting workers have also proven to be less effective than elimination, substitution, and engineering because the focus is on controlling employee behaviors rather than hazards. An important principle to remember is that "any system that relies on behavior is inherently unreliable."

Personal Protective Equipment (PPE)

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PPE works only when workers properly use it.

Personal protective equipment is equipment worn to minimize exposure to hazards that cause serious workplace injuries and illnesses. These injuries and illnesses may result from contact with chemical, radiological, physical, electrical, mechanical, or other workplace hazards. Personal protective equipment may include items such as gloves, safety glasses and shoes, earplugs or muffs, hard hats, respirators, or coveralls, vests and full body suits.

When engineering, work practice, and administrative controls are not feasible or do not provide sufficient protection, employers must provide personal protective equipment to their workers and ensure its proper use. PPE should be used in conjunction with, not instead of, the other hazard control strategies. A common mistake some managers and supervisors make is that they try to save a little money when purchasing PPE. Do not skimp on quality PPE: it can save a life.

Employers are also required to train each worker required to use personal protective equipment to know:

  • Why it is necessary
  • When it is necessary
  • What kind is necessary
  • How to properly put it on, adjust, wear and take it off
  • The limitations of the equipment
  • Proper care, maintenance, useful life, and disposal of the equipment

If PPE is to be used, a PPE program should be implemented. This program should address the hazards present; the selection, maintenance, and use of PPE; the training of employees; and monitoring of the program to ensure its ongoing effectiveness.

Hierarchy of Controls

Hierarchy of hazard control is a system used in industry to minimize or eliminate exposure to hazards. It is a widely accepted system promoted by numerous safety organizations. This concept is taught to managers in industry, to be promoted as standard practice in the workplace. Credit: Pertrain Pty Limited (2:06)


Before beginning this quiz, we highly recommend you review the module material. This quiz is designed to allow you to self-check your comprehension of the module content, but only focuses on key concepts and ideas.

Read each question carefully. Select the best answer, even if more than one answer seems possible. When done, click on the "Get Quiz Answers" button. If you do not answer all the questions, you will receive an error message.

Good luck!

1. Hazard control strategies attempt to eliminate or reduce ________.

2. Which hazard control strategy is most effective in protecting employees?

3. Which of the following hierarchy of controls uses solutions that are independent of human behavior?

4. Which Hierarchy of Controls strategy addresses how work is to be performed?

5. What is a common mistake some managers and supervisors make when they purchase PPE?

Have a great day!

Important! You will receive an "error" message unless all questions are answered.