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Safety guides and audits to make your job as a safety professional easier

Controlling Hazards

The Almighty Hierarchy!

Hierarchy of Controls
If you eliminate the hazard, exposure isn't possible.
(Click to enlarge)

As you learned earlier, there are many different types of hazards in the workplace. Hazardous conditions include unsafe materials, equipment, environment and employees. Unsafe work practices include: allowing untrained workers to perform hazardous tasks, taking unsafe shortcuts, horseplay, or long work schedules. To combat these hazardous conditions and unsafe work practices, control strategies, called the "Hierarchy of Controls" have been developed.

Traditionally, a hierarchy of controls has been used as a means of determining how to implement feasible and effective controls. ANSI Z10-2005, Occupational Health and Safety Management Systems, encourages employers to employ the following five hazard control strategies:

  1. Elimination
  2. Substitution
  3. Engineering controls
  4. Administrative controls
  5. Personal protective equipment

The 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 normally leads to the implementation of inherently safer systems, ones where the risk of illness or injury has been substantially reduced. Let's take a closer look at the hierarchy of control strategies.

Check out this short audio clip by Dan Clark of the theSafetyBrief.com talks about the Hierarchy of Controls.

"Feasible" Controls

guardrail
Hazard correction must be feasible.

Hazard abatement measures required to correct a hazard must be technologically and economically feasible for the employer. OSHA uses the following criteria to determine feasibility of engineering and administrative controls:

  • Technical Feasibility: Technical feasibility is the existence of technical know-how as to materials and methods available or adaptable to specific circumstances which can be applied to cited violations with a reasonable possibility that employee exposure to occupational health hazards will be reduced.

  • Economic Feasibility: Economic feasibility means that the employer is financially able to undertake the measures necessary to abate identified hazards. Economic feasibility is a major issue to be considered when imposing hazard controls.

  • OSHA may allow the use of PPE to abate a hazard, at least until such time as engineering controls become a less significant economic burden for the company when the following conditions are met:

    1. If significant reconstruction of a single establishment involving a capital expenditure which would seriously jeopardize the financial condition of the company is the only method whereby the employer could achieve effective engineering controls;

    2. If there are no feasible administrative or work practice controls; and
    3. If adequate personal protective equipment or devices are available.

Elimination and Substitution

Elimination and substitution, while most effective at reducing hazards, also tend to be the most difficult to implement in an existing process. If the process is still at the design or development stage, elimination and substitution of hazards may be inexpensive and simple to implement. For an existing process, major changes in equipment and procedures may be required to eliminate or substitute for a hazard.

These strategies are considered first because they have the potential to completely eliminate the hazard, thus greatly reducing the probability of an accident due to the hazard.

Some examples of these two strategies include:

  • Removing the source of excessive temperatures, noise, or pressure - this is "elimination".
  • Substituting a toxic chemical with a less toxic or non-toxic chemical - this is "substitution".
engineering controls
Design the hazard out of the equipment.

Engineering Controls

These controls focus on eliminating or reducing the actual source of the hazard, unlike other control strategies that generally focus on employee exposure to the hazard. The basic concept behind engineering controls is that, to the extent feasible, the work environment and the job itself should be designed to eliminate hazards or reduce exposure to hazards. While this approach is called engineering controls, it does not necessarily mean that an engineer is required to design the control. Redesigning or replacing equipment or machinery may be expensive, but remember, according to the National Safety Council, the cost per medically consulted injury in 2013 was $42,000, and the cost per death was $1,450,000.

Remember: No hazard + No exposure = No accident.

Engineering controls do not necessarily have to be expensive or complicated. They can be quite simple in some cases. Engineering controls are based on the following broad strategies:

  1. If feasible, design or redesign the tools, equipment, machinery, materials and/or facility.
  2. Enclose the hazard to prevent exposure in normal operations; and
  3. If complete enclosure is not feasible, establish barriers or local ventilation to reduce exposure to the hazard in normal operations.

Some examples of this strategy include:

  • Redesigning a process to reduce exposure to a hazardous moving part;
  • Redesigning a work station to relieve physical stress and remove ergonomic hazards; or
  • Designing general ventilation with sufficient fresh outdoor air to improve indoor air quality and generally to provide a safe, healthful atmosphere.

Enclosure of Hazards

When you cannot remove a hazard and cannot replace it with a less hazardous alternative, the next best control is enclosure. Enclosing a hazard usually means that there is no hazard exposure to workers during normal operations. There still will be potential exposure to workers during maintenance operations or if the enclosure system breaks down. For those situations, additional controls such as safe work practices or personal protective equipment (PPE) may be necessary to control exposure.

Some examples of enclosure designs are:

  • Complete enclosure of moving parts of machinery;
  • Complete containment of toxic liquids or gases from the beginning to end of a process;
  • Glove box operations to enclose work with dangerous microorganisms, radioisotopes, or toxic substances; and
  • Complete containment of noise, heat, or pressure producing processes with materials especially designed for those purposes.

Barriers or Local Ventilation

When the potential hazard cannot be removed, replaced, or enclosed, the next best approach is a barrier to the exposure or, in the case of air contaminants, local exhaust ventilation to remove the contaminant from the workplace. This engineered control involves potential exposure to the worker even in normal operations. Consequently, it should be used only in conjunction with other types of controls, such as safe work practices designed specifically for the site condition and/or PPE. Examples include:

  • Ventilation hoods in laboratory work
  • Machine guarding, including electronic barriers
  • Isolation of a process in an area away from workers
  • Baffles used as noise-absorbing barriers
  • Nuclear radiation or heat shields
trench
How do you control unsafe behaviors?

Administrative Controls

Administrative controls are aimed at reducing employee exposure to hazards that engineering controls fail to eliminate. Administrative controls work by designing safe work practices into job procedures and adjusting work schedules. Ultimately, effective administrative controls will successfully eliminate the human behaviors that result in 95% of all workplace accidents!

Administrative controls are only as effective as the safety management system that supports them. It's always better to eliminate the hazard so that you don't have to rely on management controls that tend to work only as long as employees behave. Here's an important principle that reflects this idea:

Any system that relies on human behavior is inherently unreliable.

To make sure management controls are effective in the long term, they must be designed from a base of solid hazard analysis and sustained by a supportive safety culture. They then must be accompanied by adequate resources, training, supervision, and appropriate consequences. Remember, administrative controls should be used in conjunction with, and not as a substitute for, more effective or reliable engineering controls. Now let's look at some examples of some administrative controls.

Safe Work Practices

unsafe behavior
Can you see the missing PPE?

Safe work practices may be quite specific or general in their applicability. They may be a very important part of a single job procedure or applicable to many jobs in the workplace. Safe work practices include:

  • Removing tripping, blocking, and slipping hazards
  • Removing accumulated toxic dust on surfaces
  • Wetting down surfaces to keep toxic dust out of the air
  • Using safe lifting techniques
  • Maintaining equipment and tools in good repair
  • Using personal protective equipment (PPE)

Other safe work practices apply to specific jobs in the workplace and involve specific procedures for accomplishing a job. To develop safe procedures, you conduct a job hazard analysis (JHA). If, during the JHA, you determine that a procedure presents hazards to the worker, you would decide that a training program is needed. We recommend using the JHA as a tool for training your workers in the new procedures. A training program may be essential if your employees are working with highly toxic substances or in dangerous situations.

ppe
Wearing PPE is always a best practice.

Personal Protective Equipment (PPE)

Using personal protective equipment is a very important safe work practice. It's important to remember that, like other administrative controls, the use of PPE does not control the hazard itself, but rather it merely controls exposure to the hazard by setting up a barrier between the employee and the hazard. Use of PPE may also be appropriate for controlling hazards while engineering controls are being installed or work practices developed.

PPE Drawbacks

The limitations and drawbacks of safe work practices also apply to PPE. Employees need training in why the PPE is necessary and how to use and maintain it. It also is important to understand that PPE is designed for specific functions and are not suitable in all situations. For example, no one type of glove or apron will protect against all solvents. To pick the appropriate glove or apron, you should refer to recommendations on the material safety data sheets of the chemicals you are using.

Your employees need positive reinforcement and fair, consistent enforcement of the rules governing PPE use. Some employees may resist wearing PPE according to the rules, because some PPE is uncomfortable and puts additional stress on employees, making it unpleasant or difficult for them to work safely. This is a significant drawback, particularly where heat stress is already a factor in the work environment. An ill-fitting or improperly selected respirator is particularly hazardous, since respirators are used only where other feasible controls have failed to eliminate a hazard.

workers
There's always a possible interim measure.

Interim Measures

When a hazard is recognized, the preferred correction or control cannot always be accomplished immediately. However, in virtually all situations, interim measures can be taken to eliminate or reduce worker risk. These can range from taping down wires that pose a tripping hazard to actually shutting down an operation temporarily.

The importance of taking these interim protective actions cannot be overemphasized. There is no way to predict when a hazard will cause serious harm, and no justification to continue exposing workers unnecessarily to risk. By the way, OSHA believes there is always some kind of interim measure that can be used to temporarily abate a hazard.

Maintenance Strategies to Control Hazards

workers
Preventive maintenance is proactive!

There are two general types of maintenance processes needed to control hazards:

  • Preventive maintenance to make sure equipment and machinery operates safely and smoothly.
  • Corrective maintenance to make sure equipment and machinery gets back into safe operation quickly.

Hazard Tracking Procedures

An essential part of any day-to-day safety and health effort is the correction of hazards that occur in spite of your overall prevention and control program. Documenting these corrections is equally important, particularly for larger sites.

Documentation is important because:

  • It keeps management and safety staff aware of the status of long-term correction items;
  • It provides a record of what occurred, should the hazard reappear at a later date; and
  • It provides timely and accurate information that can be supplied to an employee who reported the hazard.

Final Words

The hierarchy of controls is the standard system of strategies to effectively eliminate workplace hazards. Remember, the first question to ask when considering ways to eliminate a hazard is, "can we apply engineering controls?" You may need to use a combination of strategies to effectively eliminate the hazard. Whatever it takes, do it. You are not just saving a life....you are saving a father, a mother, a son, or a daughter....you are saving a family. It's worth the effort!

There's a lot of information in this module, and it may take some time for the concepts to sink in, but not to worry, go ahead and complete the MODULE QUIZ.

Instructions

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. Which of the following is not one of the five basic hazard control strategies discussed in the text?

2. Why do OSHA standards require the employer to first consider engineering controls to correct workplace hazards?

3. Engineering controls should not rely on which of the following strategies?

4. Which of the controls listed below is most likely to eliminate a toxic chemical hazard?

5. Administrative controls are only as effective as the _____.

6. Ultimately, effective administrative controls have the potential to successfully eliminate the workplace behaviors that result in _____ percent of all workplace accidents.

7. Administrative controls should be used _____ engineering controls.

8. To pick the appropriate glove or apron, you should refer to recommendations on the _____ of the chemicals you are using.

9. _____ is a strategy to make sure equipment and machinery operates safely and smoothly.

10. Which of the following is the least important reason for tracking workplace hazards?


Have a great day!

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