Occupational safety and health professionals use a framework called the "hierarchy of controls" to select ways of controlling workplace hazards. In other words, the best way to control a hazard is to systematically remove it from the workplace, rather than relying on workers to reduce their exposure. During a COVID-19 outbreak, when it may not be possible to eliminate the hazard, the most effective protection measures are (listed from most effective to least effective): engineering controls, administrative controls, safe work practices (a type of administrative control), and PPE.
There are several models for the hierarchy of controls by safety professionals and training providers. Our training uses the hierarchy of controls model detailed in ANSI/ASSP Z10, Occupational & Safety Management Systems.
Click on the buttons below to see a short summary and a video of the hierarchy of controls.
It's very important to understand that no one control measure may be totally effective against exposure. The most effective strategy to protect employees and the public is to use a combination of the hierarchy of control measures to best protect against exposure to infectious diseases. We will discuss each of the control measures in the next several sections.
Engineering controls to reduce exposure to infectious diseases through the design of equipment. The advantage of using engineering controls is that they reduce exposure to hazards without relying on worker behavior and can be the most cost-effective solution to implement. Engineering controls for SARS-CoV-2 and other viruses include:
Warnings help raise general awareness about entering biohazard areas, but they do not prevent entry. Warnings work only as long as employees comply with them. Generally, warnings include signs, alarms, and labels.
All signs must be well lit and kept clean so that they are easily visible. Statements that contradict or detract from the signs' meaning are prohibited. Signs required by other statutes, regulations, or ordinances, however, may be posted in addition to, or in combination with, this sign.
Administrative controls require action by the worker or employer. Typically, administrative controls are changes in work policies, programs, processes, and procedures to reduce or minimize exposure to a hazard. Examples of administrative controls for SARS-CoV-2 include:
Click on the buttons below to see two short videos with discussions giving examples of administrative controls and social distancing.
Safe work practices are types of administrative controls that include procedures for safe and proper work used to reduce the duration, frequency, or intensity of exposure to a hazard. Examples of safe work practices for SARS-CoV-2 include:
Click on the buttons below to see a short video on effective personal hygiene practices and an NFPA warning about using hand sanitizers.
While engineering and administrative controls are considered more effective in minimizing exposure to viruses, PPE may also be needed to prevent certain exposures. While correctly using PPE can help prevent some exposures, it should not take the place of other prevention strategies.
Examples of PPE include: gloves, goggles, face shields, and respiratory facepieces. Don't think of face masks as PPE because they are used to primarily protect others, not the user. During an outbreak of an infectious disease, such as COVID-19, recommendations for PPE specific to occupations or job tasks may change depending on:
Employers are obligated to pay for and provide their workers with PPE needed to keep them safe while performing their jobs. The types of PPE required during an outbreak will be based on the risk of being infected while working and job tasks that may lead to exposure.
All types of PPE must be:
Click on the video below to see information on basic types of PPE.
Unlike NIOSH-approved N95s, facemasks are loose-fitting and provide only barrier protection against droplets, including large respiratory particles. No fit testing or seal check is necessary with facemasks. Most facemasks do not effectively filter small particles from the air and do not prevent leakage around the edge of the mask when the user inhales.
The role of facemasks is for patient source control, to prevent contamination of the surrounding area when a person coughs or sneezes. Therefore they do not perform the same function as a N95 filtering facepieces and should not be considered PPE. People with confirmed or suspected COVID-19 should wear a facemask until they are isolated in a hospital or at home. The person does not need to wear a facemask while isolated. See Understanding the Difference info graphic for more information.
The CDC does not recommend that the general public routinely wear N95 respirators to protect themselves from respiratory diseases, including coronavirus (COVID-19). The best way to prevent illness is to avoid being exposed to this virus. However, as a reminder, CDC always recommends everyday preventive actions, such as hand washing, to help prevent the spread of respiratory diseases. More information.
Filtering facepieces are the primary respirator being used for COVID-19. An N95 FFR is a type of respirator which removes particles from the air that are breathed through it. These respirators filter out at least 95% of very small (0.3 micron) particles. N95 FFRs are capable of filtering out all types of particles, including bacteria and viruses. See approved manufacturers.
Click on the button below to see an example of an approved N95 filtering facepiece.
For a list of N95 and other approved respirator models see the NIOSH-Approved Particulate Filtering Facepiece webpage.
The appropriate form of respirator will depend on the type of exposure and on the transmission pattern of COVID-19. See the NIOSH "Respirator Selection Logic" or the OSHA "Respiratory Protection eTool."
Click on the button below to see video on how put on and take off N95 filtering facepieces (masks).
Fit testing is a procedure used to determine how well a respirator "fits"—that is, whether the respirator forms a seal on the user's face. Before any employee first starts wearing a respirator in the work environment, the employer must perform a respirator fit test. For all employees wearing negative or positive pressure tight-fitting facepiece respirators, the employer must perform either qualitative or quantitative fit tests using an OSHA-accepted fit testing protocol. In addition, employees must be fit tested whenever a different respirator facepiece is used, and at least annually thereafter.
If an employee has difficulty breathing during a fit test or while using a respirator, the employer must make a medical examination available to that employee to determine whether he or she can wear a respirator safely.
Click on the button below to see a DOL-OSHA video about respirator fit testing.
Respiratory protection is no better than the respirator in use, even though it is worn correctly. Frequent random inspections must be conducted by a qualified individual to make sure respirators are properly selected, used, cleaned, and maintained.
All respirators: For all respirators, inspections must include a check of respirator function, tightness of connections, and the condition of the various parts including, but not limited to the:
It's especially important to evaluate elastic parts for pliability and signs of deterioration.
Respirator training is an important part of the respiratory protection program. As you learned earlier, initial and annual respirator education should include three components: instruction, training, and evaluation to ensure employees have the necessary knowledge, skills, and abilities (KSAs) required to use respirators on the job.
Retraining must be done annually and under some conditions, additional retraining might be required. Circumstances which would require retraining include situations where:
Note: If an employee has adequate KSAs, but is intentionally violating safety rules covering respiratory protection program, policies, and rules, retraining may not be the most appropriate response. More appropriately, the intentional violation of an OSHA or employer safety rule may require progressive disciplinary action, if justified.
Respiratory protection training should address selection, use (including donning and doffing), proper disposal or disinfection, inspection for damage, maintenance, and the limitations of respiratory protection equipment. Learn more at OSHA's Respiratory Protection Overview.
Click on the button below to see an OSHA video on respirator program training requirements.
For more information on OSHA training requirements see OSHA Pub 2254, Training Requirements in OSHA Standards, and OSHAcademy Course 703, Introduction to OSHA Training. For more information on Respiratory Protection, see OSHAcademy Course 756.
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