Introduction A basic safety concept is that to have an accident, a hazard and exposure must exist. Simply stated, 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.

• 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?

In the metal shop (environment), while clearing a snag (trigger), a worker's hand (exposure) comes into contact with a rotating pulley. It pulls his hand into the machine and severs his fingers (consequences) quickly.

• 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 injury and lose fingers and hands.
  
  
• 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 pulley is operating. Obviously, this hazard scenario could not occur if the pulley is not rotating.
  
  
• What are other contributing factors? This hazard occurs very quickly. It does not give the worker much opportunity to recover or prevent it once his hand comes into contact with the pulley. 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 the 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.

• 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?

• (Shock. Incorrectly or inadvertently grounded). Contact with exposed conductors or a device. Example: a metal ladder comes into contact with power lines. 60Hz alternating current (common house current) is very dangerous because it can stop the heart.



• (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.



• (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.



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

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



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

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