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Everyday exposure in construction.

Hazard Categories


In the first module, we began a discussion of the concepts of "hazard" and "exposure" in preparation for a further look in this module. Here we will take a closer look at the five general hazard categories and 13 more specific hazard categories. 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 areas. 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 - anyone in the workplace (i.e., employees, guests, customers or contractors)
  • System - flawed policies, programs, plans, processes, procedures, and practices

1. Which one of the five hazard categories includes liquids, solids, and gases?

a. materials
b. management
c. equipment
d. environment

What You See and Don't See

Hopefully not. Inadequate shoring and lack of proper engineering controls made this a serious situation.

When you conduct a walkaround inspection you are usually looking for hazardous materials, equipment, and environmental factors. These hazard areas represent hazardous physical conditions that are rather easily recognized by the employer. However, they cause only a small percentage of all accidents in the workplace: well under 10 percent.

OSHA inspectors primarily cite hazardous conditions because they're easy to see, and "what OSHA sees, they cite." OSHA is very good at uncovering the conditions that don't cause many accidents. However, OSHA is not so good at spotting unsafe behaviors that cause most accidents. If the inspector is lucky (see video) they might catch someone violating safety rules, but that is the exception, not the rule. It's a flawed system, but it's all we have.

Most company safety inspections are no better. Safety committee members, supervisors, or safety managers walk around looking for hazardous conditions. They rarely see an unsafe practice occurring. This flaw in the inspection process also explains why there is little correlation between the most frequently cited violations and the most frequent causes of injury. For instance, ergonomic hazards, which frequently cause injuries, are not yet addressed in OSHA standards.

2. Which of the following is LEAST likely to be uncovered during a walkaround safety inspection?

a. Unsafe workspaces
b. Defective equipment
c. Hazardous chemicals
d. Unsafe behaviors

Sober and Focused

You must be sober and focused to be safe.

The fourth hazard category, People, refers employees at every level of the organization who are not "sober and focused" on the work they're doing. For example, employees might be in a hazardous "state of being" if they are:

  • in a hurry
  • under the influence of drugs or alcohol;
  • poorly trained or educated;
  • worried about a family illness;
  • too tired to do the job; or
  • distracted for any reason.

Remember, an employee who is distracted in from the work they're doing should also be considered a "walking hazardous condition" that increases the likelihood of an unsafe behavior. Today, distraction is becoming a big problem with the use of cell phones, especially while people are walking or driving. Unfortunately, OSHA does not usually observe employees working in an unsafe manner, so you don't see unsafe behaviors described in OSHA citation reports too often.

The safety management system is composed of policies, programs, plans, processes, procedures and practices that may influence or contribute to distraction and other unsafe behaviors in the workplace. A flawed safety management system will contribute to workplace conditions and behaviors. Therefore we can argue that the failure of the safety management system is ultimately the root cause for the majority of the workplace accidents.

3. What is ultimately the root cause for the majority of workplace accidents?

a. Failure of the safety management system
b. Distracted employees
c. A lack of common sense
d. Lack of management competence

Hazardous Materials

Every workplace has 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. 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. These symptoms should be viewed as visible signs of potential disease. Excessive and continued exposure to certain solvents may result in liver, lung, kidney, and reproductive damage, as well as cancer.

Click to see a

Common types of solvents:

trichloroethylene toluene
acetone methylene chloride
percholoroethylene glycol ether
isopropyl alcohol Chloroform
xylene freon

Acids and Alkalis: Acids and alkalis may cause serious burns if they are splash 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. Workers can be exposed to these and other gases during work. Potential exposure to gases occurs through inhalation. Such exposure may produce eye damage, headaches, shivering, tiredness, nausea, and possible kidney and liver damage.

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.

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.

Gases: Gases like hydrogen sulfide, methane, etc. Gas may be extremely hazardous if leaked into the atmosphere. Employees should know the signs and symptoms related to hazardous gases in the workplace.

4. These types of hazardous materials may cause serious burns if they are splashed into the eyes.

a. Solvents
b. Plastics and resins
c. Acids and alkalis
d. Gases
Heavy equipment is always dangerous.

Hazardous Equipment

Hazardous equipment includes vehicles, machinery, and tools.

  • 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 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.

5. Which program should be in place to make sure equipment operates properly?

a. A corrective maintenance program
b. A preventive maintenance program
c. An as-needed maintenance program
d. A just-in-time lean maintenance program
Work environments can be very hazardous.

Hazardous Work Environments

The work environment includes all areas where work is being performed. Examples include work environments that are too noisy, bright, dark, hot, cold, dusty, dirty, messy, or wet. Is it too noisy, or are dangerous gases, vapors, liquids, fumes, etc., present? Such factors all contribute to an unsafe environment. You can bet a messy workplace is NOT a safe workplace! Common environmental hazards include:

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:

  1. both wires of an energized electrical circuit,
  2. one wire of an energized electrical circuit and the ground, or
  3. an energized "hot" metallic part and 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. More on this topic in course 711, Introduction to Ergonomics.

6. Which of the following may cause an electric shock to a person?

a. Contact with the ground wire of an electrical circuit
b. Contact with any metal and the ground
c. Contact with both wires of an energized electric circuit
d. Contact with the non-metallic part of a wire
People can be "walking hazards".

Hazardous People

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. As mentioned earlier, hazardous work practices represent about 95% of the causes of all accidents in the workplace. Bottom-line: If employees are not sober and focused while working, they are walking hazardous conditions.

  • Management may unintentionally promote unsafe work practices by establishing policies, procedures and rules (written and unwritten) that ignore or actually direct unsafe work practices. These safety policies, plans, programs, processes, procedures and practices are called "system controls" and ultimately represent the causes of about 98% of all workplace accidents.

Hazardous System

Every company has, to some degree, a safety management system. Management may unintentionally promote unsafe behaviors by developing ineffective policies, procedures and rules (written and unwritten) that ignore safe behaviors or actually direct unsafe work practices. Safety policies, plans, programs, processes, procedures and practices are called "Administrative Controls," and they ultimately represent the causes for about 98% of all workplace accidents.

7. What is probably the greatest reason employees perform unsafe actions?

a. They are under the influence of drugs or alcohol
b. They are fatigued
c. They are stressed by others
d. They are in a hurry

13 Hazard Categories

Safety Memo - Accidents: Six Causes. (2:30)

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.
  4. 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.

8. What type of hazard are employees exposed to when working from any height above the ground?

a. Mechanical hazard
b. Acceleration hazard
c. Environmental hazard
d. Vibration hazard

13 Hazard Categories (Continued)

Strains and sprains are very common.
  1. 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.
  2. 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.
  3. 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.
  4. 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. What type of hazard are employees exposed to when physically lifting or lowering equipment as part of their work?

a. Ergonomic hazard
b. Vibration hazard
c. Acceleration hazard
d. Psychosocial hazard

13 Hazard Categories (Continued)

ABCs of Radiation - David Ruzek (18:33)
  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 equipment such as jack hammers.

10. What type of hazard is an employee exposed to using a tool with rotating parts?

a. Pressure hazard
b. Toxic hazard
c. Mechanical hazard
d. Vibration/Noise hazard

Check your Work

Read the material in each section to find the correct answer to each quiz question. After answering all the questions, click on the "Check Quiz Answers" button to grade your quiz and see your score. You will receive a message if you forgot to answer one of the questions. After clicking the button, the questions you missed will be listed below. You can correct any missed questions and check your answers again.

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