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. Traditionally, a hierarchy of strategies to control hazards has been used to implement feasible and effective controls. In our training, we encourage the use of the "Hierarchy of Controls" (HOC) described within the ANSI/ASSP Z10-2012, Occupational Health and Safety Management Systems. The six strategies in this model include:
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.
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:
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:
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:
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.
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:
Some examples of this strategy include:
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:
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:
With the release of ANSI Z10-2012, "warnings" have been promoted to their own hierarchy level. Previously they were considered part of administrative controls. Warnings do not prevent exposure to a hazard, but they do provide a visual or audible indicator to warn people of potential danger.
Warnings can be either visual, audible, or both. They may also be tactile. Some examples of warnings are:
For instance, a door could have both a sign warning of a hazard as well as an alarm if opened. Warnings can be effective deterrents, but are not as effective as elimination, substitution, or engineering controls.
OSHA's 1910.145, Specifications for accident prevention signs and tags details the following types of signs:
One potential problem when using warnings is the misinterpretation of the warning itself. Does the symbol or text clearly explain what the hazard is to the public? For example, if a sign only contains a written warning, someone might read the sign but not know what the warning actually means. Or, if an alarm sounds, what does the alarm mean? These are challenges when using warnings and why they are not as effective as higher-level controls.
Administrative controls work by developing safety policies, programs, procedures, and designing safe work practices into job procedures. Ultimately, administrative controls can potentially influence workplace behaviors causing most of the 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.
Administrative controls also take the form of safe work practices. They 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:
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.
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.
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's also important to understand that PPE is designed for specific functions and is 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.
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.
There are two general types of maintenance processes needed to control hazards:
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:
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!
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