Course 122 Introduction to Hazard Controls

Identifying Hazards

What is a Hazard?

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How many hazards can you spot?

OSHA defines a hazard as, "a danger which threatens physical harm to employees." Expanding on that basic definition we can think of a hazard as an:"unsafe workplace condition or practice (danger) that could cause and injury or illness (harm) to employees."

A hazard may be an object or thing that is present or absent (e.g.,tools, equipment, machinery, materials). It may also be or a worker (e.g., when hurried, distracted, or mentally/physically incapable). It's important to know that a hazard is only one factor causing accidents. Before an injury accident can occur, two factors must be present:

  1. a hazard, and
  2. employee exposure to the hazard.

It takes both a hazard and exposure to a hazard to cause an accident. No hazard: no accident. No exposure: no accident.

Look Around

If you look around the workplace, you may be able to locate a few hazardous conditions or unsafe work practices without too much trouble. Did you know that, at any time, OSHA inspectors can announce their presence at your business front door to begin a comprehensive compliance inspection. What would they find? What do they look for? If you used the same inspection strategy as an OSHA inspector, wouldn't that be smart? You can get a good idea what OSHA looks for by reviewing the OSHA Field Operations Manual (FOM) and OSHA Technical Manual(OTM).

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1. Before an accident can occur, _____ must exist.

a. a sequence of related events
b. a series of unrelated behaviors
c. a hazard and exposure to the hazard
d. a person must engage in an unsafe behavior

"Recognized" Hazards

Safety Memos - Top 10 Blind Spots (2:53)

Occasionally, students ask what is considered a "recognized" hazard in the workplace. As described in OSHA's Field Compliance Manual, recognition of a hazard is established on the basis of industry recognition, employer recognition, or "common sense" recognition criteria.

  • Industry Recognition: A hazard is recognized if the employer's industry recognizes it. Recognition by an industry, other than the industry to which the employer belongs, is generally insufficient to prove industry recognition.
  • Employer Recognition: A recognized hazard can be established by evidence of actual employer knowledge. Evidence of such recognition may consist of written or oral statements made by the employer or other management or supervisory personnel during or before the OSHA inspection, or instances where employees have clearly called the hazard to the employer’s attention.
  • Common Sense Recognition: If industry or employer recognition of the hazard cannot be established, recognition can still be established if it is concluded that any reasonable person would have recognized the hazard. This argument is used by OSHA only in flagrant cases. Note: Throughout our courses we argue that "common sense" is a dangerous concept in safety. Employers should not assume that accidents in the workplace are the result of a lack of common sense.

"Foreseeable" Hazards

Another important question to ask about the nature of a hazard relates to whether it was "foreseeable." The question of foreseeability should be addressed by safety managers during the root cause analysis phase of an accident investigation. A hazard for which OSHA issues a citation must be reasonably foreseeable.

2. Which category of recognized hazards is used by OSHA only in flagrant cases?

a. Industry recognition
b. Common sense recognition
c. Employer recognition
d. Employee recognition

What is "Exposure?"

In this section, we'll discuss the concept of "exposure:" the second variable in the accident formula. Exposure is generally defined as "the condition of being exposed," or as "a position in relation to a hazard." In this course we will consider three forms of exposure that we'll discuss here: physical, environmental, and potential exposure:

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Is there a potential for an injury or fatality here?

Physical Exposure: We may think of this form of exposure as "arm's length" exposure. If any part of the body can be injured as a result of proximity to a danger zone, physical exposure exists. For instance, if an employee removes a guard and works around moving parts that could cause an injury, that employee is exposed.

Environmental Exposure: An employee may suffer from environmental exposure no matter how far away from the source of the hazard he or she might be. For instance, if an employee uses a loud saw all day, everyone working around the saw may be exposed to hazardous levels of noise and suffer from environmental exposure.

Potential Exposure: The possibility that an employee could be exposed to a hazardous condition exists when the employee can be shown to have access to the hazard. Potential employee exposure could include one or more of the following:

  • When a hazard has existed and could recur because of work patterns, circumstances, or anticipated work requirements and it is reasonably predictable that employee exposure could occur.
  • When a hazard would pose a danger to employees simply by employee presence in the area and it is reasonably predictable that an employee could come into the area during the course of the work, to rest or to eat at the jobsite, or to enter or to exit from the assigned workplace.
  • When a hazard is associated with the use of unsafe machinery or equipment or arises from the presence of hazardous materials and it is reasonably predictable that an employee could use the equipment or be exposed to the hazardous materials in the course of work.

3. When an employee has access to a hazard, which of the following categories of exposure exists?

a. Physical exposure
b. Environmental exposure
c. Reasonable exposure
d. Potential exposure


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Just remember MEEPS!

It's helpful to think of workplace hazards as existing in five general hazard categories and 13 more specific types. We'll take a look at the five hazard categories and 13 hazard types throughout the rest of this module. All this will help you improve your knowledge and skills in proactive hazard identification to help eliminate hazards in the workplace.

Five General Hazard Areas

All workplace hazards exist in five general categories. You can remember them by using the mnemonic, "MEEPS". Here are some examples:

  • Materials - liquids, solids, gases, etc.
  • Equipment - includes machinery, tools, devices
  • Environment - noise, radiation (non-ionizing and ionizing), humidity, temperature, atmospheres, workstation design
  • People - unsafe behaviors, employee fatigue, stress, hurry, drugs, etc.
  • System - flawed policies, programs, plans, processes, procedures, and practices

4. Which hazard category describes accidents due to horseplay, working too fast, or fatigue?

a. Materials
b. Equipment
c. People
d. System


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Every workplace has exposure to hazardous materials.

Nearly every production job involves the use of hazardous materials including chemicals for cleaning, stripping, or degreasing parts and equipment. Maintenance workers who enter enclosed or confined spaces are also exposed to toxic substances.

Solvents: Solvents are used to dissolve various materials. Those commonly used include:

trichloroethylene toluene
acetone methylene chloride
percholoroethylene glycol ether

Exposure occurs by inhalation, ingestion, and absorption primarily through skin contact. Skin exposure may result in dermatitis or skin rash, edema or swelling, and blistering. Solvents can dissolve the body's natural protective barrier of fats and oils leaving the skin unprotected against further irritation.

Inhaling or ingesting solvents may affect the central nervous system, acting as depressants and anesthetics causing headaches, nausea, drowsiness, dizziness, complaints of irritation, abnormal behavior, general ill-feeling, and even unconsciousness.

Acids and Alkalis: Acids and alkalis may cause serious burns if they are splashed into the eyes or onto the skin. If vapors or mists are inhaled, they may result in a burning of the linings of the nose, mouth, throat, and lungs.

Metals: Employees are exposed to metals primarily by skin contact and by inhalation of metal dusts and fumes. Exposure may cause headaches, general ill-feeling, anemia, central nervous system and kidney damage, and reproductive problems, as well as cancer.

Gases: Gases are used in many operations and may combine with other substances to produce toxic gases such as phosgene, ozone, and carbon monoxide. Common hazardous gases are hydrogen sulfide and methane. Potential exposure to gases occurs through inhalation. Exposure may produce eye damage, headaches, shivering, tiredness, nausea, and possible kidney and liver damage.

Solids: Solids like metal, wood, plastics. Raw materials used to manufacture products are usually bought in large quantities, and can cause injuries or fatalities in many ways.

Plastics and Resins: Inhalation or skin contact may occur when curing resins; cutting, heating, or stripping wires; or cutting, grinding, or sawing a hardened product. Exposure to these substances may result in skin rash and upper respiratory irritation.

Polychlorinated Biphenyls (PCBs): PCBs are used as insulators in some electrical equipment and present a potential hazard to workers. Exposures to PCBs may cause skin disorders, digestive problems, headaches, upper respiratory irritations, reproductive problems, and cancer.

Fiberglass and Asbestos: Fiberglass and asbestos are also used as fillers in epoxy resins and other plastics, in wire coatings or electrical insulation, and in printed circuit boards. Uncontrolled exposures may produce skin and upper respiratory irritations and, in the case of asbestos, cancer.

5. Hydrogen sulfide, plastics, asbestos, and solvents are examples of the _____ category of hazards.

a. environmental
b. people
c. materials
d. chemical
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Heavy equipment is always dangerous.


Hazardous equipment includes machinery and tools.

  • Equipment: Hazardous equipment should be properly guarded so that it's virtually impossible for a worker to be placed in a danger zone around moving parts that could cause injury or death. A preventive maintenance program should be in place to make sure equipment operates properly. A corrective maintenance program is needed to make sure equipment that is broken, causing a safety hazard, is fixed immediately.
  • Tools: Tools need to be in good working order, properly repaired, and used for their intended purpose only. Any maintenance person will tell you that an accident can easily occur if tools are not used correctly. Tools that are used while broken are also very dangerous.
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An noisy work environment can cause hearing damage.


Are there areas in your workplace that are too bright, dark, hot, cold, dusty, dirty, messy, wet, etc.? Is it too noisy, or are dangerous gases, vapors, liquids, fumes, etc., present? Do you see short people working at workstations designed for tall people? Such factors all contribute to an unsafe environment. You can bet a messy workplace is NOT a safe workplace!

Noise Exposure: Many work places are inherently noisy and potentially hazardous to employees. Continuous noise and instantaneous noise bursts can damage the hearing of employees. A hearing conservation program should be established if you think noise levels are a potential threat to the health of your employees. OSHA consultants, your insurer, or a private consultant are all available to help you determine noise levels in the workplace.

Electric Shock: Electricity travels in closed circuits, normally through a conductor. Shock occurs when the body becomes part of the electric circuit. The current must enter the body at one point and leave at another. Shock normally occurs in one of three ways. The person must come in contact with:

  • both wires of an electric circuit,
  • one wire of an energized circuit and the ground, or
  • a metallic part that has become "hot" by being in contact with an energized wire or conductor, while the person is also in contact with the ground.

Illumination: It's important to make sure illumination is adequate for the job being performed. Too much direct or indirect glare can, over time, cause eye strain. Too little light can result in an injury.

6. Which hazard category includes exposure to excessive noise levels?

a. Materials
b. Environmental
c. Facility
d. System
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Fatigue can cause fatalities.


This category refers to any employee (or others) at any level of the organization who is not "sober and focused" on the work they're doing. For example, an employee might be in a hazardous "state of being" if they are:

  • under the influence of legal/illegal drugs;
  • poorly trained or educated;
  • worried about a family illness; or
  • mentally or physically incapable of doing the job safely

Remember, an employee who is distracted in any way from the work they're doing should also be considered a "walking" hazardous condition that increases the likelihood of an unsafe behavior. Unfortunately, OSHA does not usually "catch" employees working in an unsafe manner, so you don't see unsafe behaviors described in OSHA citation reports too often.

Remember, hazardous conditions may be thought of as unsafe "states of being." All of the following situations may cause employees to be what I call "walking hazards"

  • Fatigue: Employees are too tired to do the work without causing injury to themselves or others.
  • Drugs or alcohol: Drugs (either legal or illegal) and alcohol place employees in altered states of awareness and lengthens reaction time.
  • Distraction: Employees who are distracted (internal thoughts are not focused on the work being performed). You can't be thinking about the football game while working on high voltage!
  • Hurry: This should be obvious. This is probably the greatest reason employees perform unsafe actions. The more hurried employees are, for whatever reason, the more likely they are going to have accidents.

Workers who take unsafe short cuts, or who are using established procedures that are unsafe, are accidents waiting to happen. Hazardous work practices represent the majority of the surface causes of all accidents in the workplace. Bottom-line: If employees are not sober and focused while working, they are walking hazardous conditions.


Every company has, to some degree, a safety management system. Management may unintentionally promote unsafe behaviors by developing ineffective policies, procedures and rules that ignore safe behaviors or actually encourage unsafe work practices. Safety policies, plans, programs, processes, procedures and practices are called "Administrative Controls," and they ultimately represent the causes all accidents, except unknowable-uncontrollable "acts of God".

7. Inadequate policies, procedures, and work practices represent _____ hazards.

a. people
b. system
c. environmental
d. social

13 Hazard Types

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Acceleration hazards exist anytime work is performed at elevation.

The following 13 hazard categories are adapted from Product Safety Management and Engineering, by Willie Hammer, ASSP Pub. This publication is an excellent text to add to your library.

  1. Acceleration: This is just a fancy term for "fall" hazard. Acceleration happens when we speed up or slow down too quickly. It also occurs when any object is being set in motion or its speed increased. Whiplash is a common injury as a result of an acceleration hazard. Hazards from deceleration and impact, especially from falls, also exist in the workplace.
  2. Biohazards: Hazards of harmful bacterial, viruses, fungi, and molds are becoming a greater concern to everyone at work. The primary routes of infection are airborne and bloodborne.
  3. Chemical reactions. Chemical reactions can be violent, and can cause explosions, dispersion of materials and emission of heat. Chemical compounds may combine or break down (disassociate) resulting in chemicals with reactive properties. Corrosion, the slow combination of iron and water, is a common chemical reaction and results in loss of strength and integrity of affected metals.

8. What kind of hazards can be violent, cause explosions, and the emission of heat?

a. Chemical reactions
b. Physical biohazards
c. Ergonomic hazards
d. Toxic substances

13 Hazard Types (Continued)

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Ergonomic hazards cause more injuries than any other hazard category.
  1. Electrical hazards: Exposure to electrical current. There are six basic electrical hazards: shock, ignition, heating/overheating, inadvertent activation (unexpected startup), failure to operate, and equipment explosion.
  2. Ergonomics: The nature of the work being done may include force, posture, position of operation characteristics that require hazardous lifting, lowering, pushing, pulling, and twisting. The results are strains and sprains to muscles and connective tissues. Overexertion represents the most common cause of injuries in the workplace. Unfortunately, OSHA rules do not cover protective measures against this type of hazard.
  3. Explosives and explosions: Explosions result in quick (instantaneous) releases of gas, heat, noise, light and over-pressure. High explosives release a large amount of energy. Low explosives burn rapidly (deflagrates) but at a slower speed. Most explosive accidents are caused by explosions of combustible gases.
  4. Flammability and fires: In order for combustion to take place, the fuel, an oxidizer, and ignition source must be present in gaseous form. Accidental fires are commonplace because fuel, oxidizers and ignition sources are often present in the workplace.
  5. Temperature: Temperature indicates the level of sensible heat present in a body. Massive uncontrolled flows of temperature extremes due to work in hot or cold environments can cause trauma and/or illness.

9. Which hazard type causes most injuries in the workplace?

a. Mechanical hazards in general industry
b. Fall hazards on construction sites
c. Ergonomic hazards - overexertion
d. Chemical reactions - acid/basic burns

13 Hazard Types (Continued)

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Mechanical hazards include moving parts, nip and pinch points, and rotating shafts.
  1. Mechanical hazards: Tools, equipment, machinery and any object may contain pinch points, sharp points and edges, weight, rotating parts, stability, ejected parts and materials that could cause injury.
  2. Pressure: Increased pressure in hydraulic and pneumatic systems. Pressure may cause ruptures in pressure vessels, whipping hoses. Small high pressure leaks may cause serious injuries.
  3. Radiation: Electromagnetic radiation hazards vary depending on the frequency (wavelength) of the energy. Generally, the higher the frequency, the more severe the potential injury. Non-ionizing (ultra-violet, visible light) may cause burns. Ionizing radiation actually has the potential to destroy tissue by dislodging electrons from atoms making up body cells.
  4. Toxics: Materials that in small amounts may cause injury to skin and internal organs are considered toxic. Toxics may enter through inhalation, ingestion, absorbed or injected.
  5. Vibration/Noise: Produce adverse physiological and psychological effects. Whole-body vibration is a common hazard in the trucking industry. Segmental vibration and noise hazards exist when working with equipment, such as jack hammers.

10. Materials that in small amounts may cause injury to skin and internal organs are considered _____.

a. toxins
b. radioactive
c. poisonous solids
d. chemical hazards

Check your Work

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Watch this short video by Oregon OSHA that introduces you to what we'll be discussing in the next module: controlling hazards. They show a good example of how an engineering control can be the solution to a hazard.

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