In 1950 the National Safety Council began describing a safety system known as the “hierarchy of controls.” This new model was created to show that that design, elimination and engineering controls are more effective in reducing risk to workers than ‘lower level controls’ such as warnings, training, procedures and personal protective equipment (PPE). The National Institute for Occupational Safety and Health (NIOSH) began to use the hierarchy of controls, and it has been an effective safety teaching tool for that organization and others over the years. The philosophy of the hierarchy- or the pyramid- is simple: “Controlling exposures to occupational hazards is the fundamental method of protecting workers.” It is simple, and although it may not be rocket science, it’s a powerful idea.
While this hierarchy is represented differently by multiple organizations, the basic protection levels of the pyramid remain the same; Elimination, Substitution, Engineering Controls, Administrative Controls, and PPE. The most effective part of the pyramid (Elimination) is at the sharp end, or the top, and the least effective (PPE) lies at the bottom.
Unfortunately, the top two most-effective layers of the safety pyramid do not work well in the laboratory setting. We can’t eliminate or substitute the biohazards we work with- that would mean not being able to perform our work. Laboratorians handle and analyze patient samples and chemicals, and they are a necessary hazardous part of the job. There is some substitution possible in the lab when considering chemicals (the use of a non-hazardous xylene substitute, for example), but for the most part, this level of the hierarchy of controls is not very helpful to the lab.
Engineering Controls involve the use of engineered machinery or equipment which reduces or eliminates exposure to a chemical or physical hazard. Engineering Controls are definitely favored over other levels on the pyramid for controlling existing worker exposures in the workplace because they are designed to remove the hazard at the source, before it comes in contact with the worker. Well-designed engineering controls can be very effective in protecting lab employees, and they are typically independent of worker interactions so they can provide that high level of protection. Sometimes the initial price of certain engineering controls can be high, but over the longer term, operating costs are frequently lower, and the controls can ultimately provide a cost savings. Good examples of engineering controls include Biological Safety Cabinets, Chemical Fume Hoods, centrifuges, and glove boxes.
The next level of the hierarchy is represented as Administrative Controls. These controls seek to improve workplace safety by creating safer policies and procedures in the workplace. Administrative Controls can range from the placement of warning signs throughout a lab, the provision of safety training programs, and the implementation of proper ergonomics. The part of the pyramid may be the most difficult to manage. The onus of workplace safety here begins to shift from management over to staff, and sometimes the results can be… unpredictable.
An off-shoot of Administrative Controls that is discussed often in safety models is known as Work Practice Controls. These controls are not truly part of hierarchy, but they can be important safety practices in the lab setting. OSHA describes Work Practice Controls as “procedures for safe and proper work that are used to reduce the duration, frequency or intensity of exposure to a hazard.” These are the not the actual written procedures, but the actions that put those written policies into action. Following proper hand hygiene and preventing eating or drinking in the laboratory are good examples of those actions.
PPE is at the bottom of the hierarchy of controls- by definition that means that it is the least effective method to keep employees from hazard exposure. It is the last resort for safety in the lab. That’s a powerful point, and it should be discussed when providing lab safety training. All too often lab staff carelessly perform tasks without wearing PPE, and the danger is immediate and potentially disastrous. Even though this level of protection is considered the least effective, this last barrier between the employee and the hazardous material is crucial. Lab staff are required to have PPE education, and they should be able to provide a return demonstration for the proper donning and doffing of that PPE.
The Hierarchy of Controls is typically represented as a pyramid. It’s a simple symbol, but it’s really a powerful and complex model for safety. When you look at each separate level, you can see that there is a great deal of information that can provide a lab safety professional with helpful resources. As a lab leader, you can use the model to provide education, train staff, and help to enforce good safety behaviors which will improve the lab safety culture and keep employees from harm.
–Dan Scungio, MT(ASCP), SLS, CQA (ASQ) has over 25 years experience as a certified medical technologist. Today he is the Laboratory Safety Officer for Sentara Healthcare, a system of seven hospitals and over 20 laboratories and draw sites in the Tidewater area of Virginia. He is also known as Dan the Lab Safety Man, a lab safety consultant, educator, and trainer.
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