There are many different types of hazards in the lab. Hazards are generally categorized into two types: 1) hazardous conditions and 2) unsafe work practices/behaviors.
To combat these hazardous conditions and unsafe work practices, a strategy, called the "Hierarchy of Controls," has been developed. Traditionally, a hierarchy of controls has been used to implement feasible and effective hazard controls. In our training, we encourage the use of the "Hierarchy of Controls" (HOC) described in ANSI/ASSP Z10-2012, Occupational Health and Safety Management Systems.
The hierarchy of controls prioritizes intervention strategies based on the premise that the best way to control a hazard is to systematically remove it from the workplace, rather than relying on workers to reduce their exposure. The types of measures that may be used to protect laboratory workers, prioritized from the most effective to least effective, are:
Following the hierarchy normally leads to the implementation of inherently safer systems, ones where the risk of illness or injury have been substantially reduced. Let's take a closer look at the hierarchy of control strategies.
Simply stated, elimination removes a hazard, and substitution replaces a hazard.
These strategies are considered first because they are most effective in completely eliminating the hazard. Removing or replacing equipment or machinery may be expensive, but remember, according to the National Safety Council, the total economic cost of a work-related medically-consulted injury is over $41,000, and $1,200,000 per death.
Elimination and substitution, while most effective at reducing hazards, tend to be the most difficult to implement in an existing process. If the process is still at the design or development stage, the elimination and substitution of hazards may be inexpensive and simple to implement. However, for an existing process, major changes in equipment and procedures may be quite expensive.
Some examples of these two strategies include:
Engineering controls work through the design or redesign of tools, equipment, and machinery to remove the hazard at the source. If elimination or substitution is not possible, OSHA law requires employers to attempt to remove hazards through the use of feasible engineering controls because they also have the potential to eliminate or reduce exposure to hazards in the lab.
These controls focus on eliminating or reducing the hazard at the source of the hazard, during the process, or and at the worker. 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 using three primary methods:
When you cannot remove a hazard and cannot replace it with a less hazardous alternative, the next best control in the laboratory is enclosure. Properly enclosing a hazard 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 effective enclosure designs are:
When the hazard cannot be removed, replaced, or completely enclosed, the next best approach is to place a barrier or guard between the worker and the hazard to prevent exposure. For more information on effective barriers, see OSHAcademy Course 726, Introduction to Machine Guarding.
Examples of effective barriers include:
Ventilation involves removing potential air contaminants during 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. In the laboratory, the most common type of ventilation is local exhaust ventilation. Some examples of ventilation controls include:
Engineering controls that design or redesign of tools, equipment, and machinery are important because they can eliminate or reduce a hazard at the source. Some examples of design methods include:
Visit the NIOSH Engineering Controls Database for more examples of engineering controls in laboratories and other workplaces.
Warnings may be visual, audible, or both. They may also be tactile.
Administrative controls include the development and deployment of safety policies, processes, procedures, rules, training, scheduling, and safe work practices. Ultimately, effective administrative controls will successfully control the human behaviors that result in most workplace accidents. Examples of laboratory administrative controls include:
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.
To make sure these 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 engineering controls.
Using personal protective equipment is a very important safe work practice. It's important to remember, 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 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 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 reduce or remove a hazard.
What two general types of maintenance processes are needed?
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 control the hazards in your laboratory is, "can we eliminate, replace, or use engineering controls?" You will more than likely use a combination of strategies to control hazards. Whatever it takes, do it. You are not just saving a life: you are saving someone's father, mother, son, or a daughter. It's worth the effort.
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