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Course 706 - Job Hazard Analysis (JHA)

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Describe the Hazards in Each Step

Look for possible hazards in each step.


A very important part in the JHA development process is to discover the hazards lurking within each step. A basic safety concept must be understood by all safety staff: to have an accident, a hazard and exposure to the hazard must exist.

  • A hazard is an unsafe condition that could cause injury or illness to an employee.

  • Exposure usually refers to an employee's placement relative to the hazard's "danger zone". If the employee is within the danger zone, the employee is exposed.

How To Identify Hazards

Whoah! Where's the guard?

A job hazard analysis is an exercise in detective work. Your goal is to discover the following:

  • What can go wrong?
  • What are the consequences?
  • How could the hazard arise?
  • What are other contributing factors?
  • How likely is it that the hazard will occur?

To make your JHA useful, document the answers to these questions in a consistent manner. Describing a hazard by answering the questions above ensures you target the most important contributors to the hazard.

How To Identify Hazards (Continued)


Rarely is an accident a simple case of one single event or cause. More frequently, many contributing events tend to line up to create the hazard. Here is an example of a hazard scenario that illustrates this idea:

Wood coming from the infeed rollers jammed up as it fell onto the chipper conveyor belt. A chipperman tried to clear the jam without turning off any part of the machine or using a picaroon. His hand and arm were caught up in the teeth of the rotating rollers, and his body was pulled onto the chipper conveyor. The chipperman's arm was twisted off at the shoulder. Another worker heard his cries and rescued him before he was pulled into the chipper. (Source: Worksafe BC)

Now, let's pretend the accident didn't happen and it was your job to identify the hazards and exposure inherent in this task. Let's ask the questions:

  • What can go wrong? The worker's hand could come into contact with a rotating object that "catches" it and pulls it into the machine.

  • What are the consequences? The worker could receive a severe or fatal injury.

  • How could it happen? The accident could happen as a result of the worker trying to clear a snag during operations or as part of a maintenance activity while the conveyor is operating. Obviously, this hazard scenario could not occur if the conveyor is not rotating.

  • What are other contributing factors? The hazards and exposure related to this task can occur very quickly. It does not give the worker much opportunity to recover or prevent it once his hand comes into contact with the rotating rollers. This is an important factor, because it helps you determine the severity and likelihood of an accident when selecting appropriate hazard controls. Unfortunately, experience has shown that training is not very effective in hazard control when triggering events happen quickly because humans can react only so quickly.

  • How likely is it that the hazard will occur? This determination requires some judgment. If there have been "near-misses" or actual cases, then the likelihood of a recurrence would be considered high. If the pulley is exposed and easily accessible, that also is a consideration. In this example, the likelihood that the hazard will occur is high because there is no guard preventing contact, and the operation is performed while the machine is running. By following the steps in this example, you can organize your hazard analysis activities.

Potential Hazards

Ask questions to uncover potential hazards.

To ensure all hazards are identified, analyze each step to uncover potential, as well as actual, hazards produced by both work environment and the action. Be sure to consider the following:

  • Is there danger of striking against, being struck by, or otherwise making harmful contact with an object?

  • Can the worker be caught in, by, or between objects?
  • Is there potential for a slip or trip?
  • Can the employee fall from one level to another or even on the same level?
  • Can pushing, pulling, lifting, lowering, bending, or twisting cause strain?

  • Is the work environment hazardous to safety or health?
  • Are there concentrations of toxic gas, vapor, fumes, or dust?
  • Are there potential exposures to heat, cold, noise, or ionizing radiation?
  • Are there flammable, explosive, or electrical hazards?

Common Hazards and Descriptions

Napo encounters many hazards.

Chemical (Toxic): A chemical that exposes a person by absorption through the skin, inhalation, or through the blood stream that causes illness, disease, or death. The amount of chemical exposure is critical in determining hazardous effects. Check Safety Data Sheets (SDS), and/or OSHA 1910.1000 for chemical hazard information.

Chemical (Flammable): A chemical that, when exposed to a heat ignition source, results in combustion. Typically, the lower a chemical's flash point and boiling point, the more flammable the chemical. Check SDS for flammability information.

Chemical (Corrosive): A chemical that, when it comes into contact with skin, metal, or other materials, damages the materials. Acids and bases are examples of corrosives.

Explosion (Chemical Reaction): Self-explanatory.

Explosion (Over Pressurization): Sudden and violent release of a large amount of gas/energy due to a significant pressure difference, such as rupture in a boiler or compressed gas cylinder.

Common Hazards and Descriptions (Continued)

NFPA 70E: Reducing Electrical Hazards.

Electrical (Shock/Short Circuit): Contact with exposed conductors or a device that is incorrectly or inadvertently grounded. Example: a metal ladder comes into contact with power lines. 60Hz alternating current (common household current) is very dangerous because it can stop the heart.

Electrical (Fire): Use of electrical power that results in electrical overheating or arcing to the point of combustion or ignition of flammables, or electrical component damage.

Electrical (Static/ESD): The moving or rubbing of wool, nylon, other synthetic fibers, and even flowing liquids can generate static electricity. This creates an excess or deficiency of electrons on the surface of material that discharges (spark) to the ground resulting in the ignition of flammables or damage to electronics or the body's nervous system.

Electrical (Loss of Power): Safety-critical equipment failure as a result of loss of power.

Common Hazards and Descriptions (Continued)

Workplace Ergonomics.

Ergonomics (Strain): Damage of tissue due to overexertion (strains and sprains) or repetitive motion.

Ergonomics (Human Error): A system design, procedure, or equipment that is error-provocative (A switch goes up to turn something off).

Excavation (Collapse): Soil collapse in a trench or excavation as a result of improper or inadequate shoring. Soil type is critical in determining the hazard likelihood.

Fall (Slip, Trip): Conditions that result in falls (impacts) from height or traditional walking surfaces (such as slippery floors, poor housekeeping, uneven walking surfaces, exposed ledges, etc.).

Fire/Heat: Temperatures that can cause burns to the skin or damage to other organs. Fires require a heat source, fuel, and oxygen.

Mechanical: Self-explanatory. Typically occurs when devices exceed designed capacity or are inadequately maintained. Skin, muscle, or body part exposed to crushing, caught-between, cutting, tearing, shearing items or equipment.

Noise: Noise levels (>85 dBA 8 hr TWA) that result in hearing damage or inability to communicate safety-critical information.

Common Hazards and Descriptions (Continued)

Vibration can be a serious hazard.

Radiation (Ionizing): Alpha, Beta, Gamma, neutral particles, and X-rays that cause injury (tissue damage) by ionization of cellular components.

Radiation (Non-Ionizing): Ultraviolet, visible light, infrared, and microwaves that cause injury to tissue by thermal or photochemical means.

Struck By (Mass Acceleration): Accelerated mass that strikes the body causing injury or death (Examples are falling objects and projectiles).

Struck Against: Injury to a body part as a result of coming into contact of a surface in which action was initiated by the person. (An example is when a screwdriver slips.)

Temperature (Heat/Cold): Temperatures that result in heat stress, extreme exhaustion, or metabolic slow down such as hypothermia.

Vibration: Segmental or whole-body vibration can cause damage to nerve endings, and organs.

Visibility: Lack of lighting or obstructed vision that results in an error or other hazard.

Weather Phenomena (Snow/Rain/Wind/Ice). Self-explanatory.

Let's see what the sample JHA looks like now that we've identified some hazards in each step.

Click to Enlarge

Sample JHA Worksheet

Click the image to enlarge the sample JHA that is being used throughout this course. It describes loading an empty truck trailer with pallets of product.

Last Words

Identifying hazards in each step is a top priority to ensuring the overall effectiveness of the process of the JHA process. With that in mind, it's time to take your module quiz. Just click on the quiz tab above.


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. An unsafe condition that could cause injury or illness to an employee is called _____.

2. This term usually refers to an employee's placement relative to the hazard's "danger zone."

3. A job hazard analysis is an exercise in detective work. Your goal is to discover all of the following, except _____.

4. Good hazard scenarios describe all of the following, except _____.

5. Which of the following should be done to ensure that all hazards associated with a step are identified?

Have a great day!

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