The Hierarchy of Controls: a Framework to Reduce Work Hazards
Illustrated as an upside-down pyramid, the hierarchy of controls is used in the workplace as a guide to rank the effectiveness of safety measures that reduce worker exposure to hazards. The hierarchy of controls has five levels. The most effective is elimination at the top of the pyramid, and the least effective is PPE at the bottom of the pyramid.
1. Elimination
2. Substitution
3. Engineering controls
4. Administrative controls
5. Personal protective equipment (PPE)
Read on to learn more about each level of control.
Elimination
Elimination completely removes the hazard, so it is the most effective control. Eliminating a hazard requires changes to the workplace and does not rely on an employee’s behavior. For example, if a harmful chemical is being used, we can stop using it, eliminating the risk. In California, the pesticide chlorpyrifos is no longer allowed to be used because it can cause health problems in children and some adults. However, eliminating a hazard is not always possible. This is especially the case if the hazard is related to environmental or climate conditions, which is why we have other levels of control.
Substitution
Substitution is replacing the hazard with something safer. For example, pesticides, including soil fumigants, are a known hazard in agriculture. Soil fumigants are toxic to people, yet they are frequently used to control pests in the soil. A safer option to soil fumigants is biosolarization. Biosolarization uses natural products and the power of the sun to destroy unwanted pests, decreasing the negative risk to human health. Dr. Chris Simmons, a researcher with WCAHS, is currently working to expand the number of crops that are known to benefit from biosolarization to decrease the need for toxic fumigation (read more about Dr. Simmons’ research).
Engineering controls
Engineering controls reduce or prevent hazards from coming into contact with the worker by creating a physical barrier or protection from the hazard. A major hazard in agriculture comes from the use of all-terrain vehicles (ATVs) on farms. Dr. Farzaneh Khorsandi, a researcher with WCAHS, is developing a rollover protection bar to decrease the risk of crushing during ATV incidents (read more about Dr. Khorsandi’s research).
Another example is the development of three-pronged ladders with shorter spaces between rungs. These ladders are used in orchards. The shorter spaces between rungs makes it easier for farmworkers to climb and reduces injuries. The third prong or pole of the ladder helps to prevent the ladder from slipping. Read more about the collaborative research that developed this ladder.
Administrative controls
When elimination or substitution are not possible, administrative controls are the next alternative. Administrative controls include policies and procedures that are put into place to improve safety and reduce the risk of injury and illness. Administrative controls aim to reduce the severity, frequency, and/or duration of an exposure.
For example, the Cal/OSHA regulation “Protection from Wildfire Smoke” requires administrative controls to prevent workers from wildfire smoke exposure. Some of these practices include requiring a supervisor to monitor the air quality and inform workers of necessary protections. Dr. Kent Pinkerton’s ongoing research on the impact of wildfire smoke on lungs contributed to our Wildfire Smoke Exposure Training. Trainings are considered an administrative control.
PPE
Personal Protective Equipment or PPE is listed at the bottom of the pyramid of controls because it is the least effective level of protection. PPE is worn by workers to minimize exposure to a hazard. PPE is the least effective control because it does not control the hazard, instead it protects the worker when the hazard occurs. Also, the effectiveness of PPE depends on whether it is the right type for the hazard, the right size for the worker, and if it is used correctly by the worker. Examples of PPE include respirators, safety glasses, gloves, coveralls, earplugs, and hard hats.
For example, it is recommended to wear PPE, such as goggles or a face shield, to help limit exposure to bird flu when milking sick dairy cows.
Resources
This article was developed by WCAHS. These materials are part of the Worker Occupational Safety and Health Training and Education Program (WOSHTEP) administered by the Commission on Health and Safety and Workers’ Compensation in the California Department of Industrial Relations through interagency agreements with the labor Occupational Health Program at the University of California, Berkeley; the Western Center for Agricultural Health and Safety at the University of California, Davis; and the Labor Occupational Safety and Health Program at the University of California, Los Angeles.
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