Exposure Control Strategies
Occupational safety and health professionals use "hierarchy of controls" to select strategies for controlling hazards at school facilities. Click to enlarge.
The Hierarchy of Controls
Occupational safety and health professionals use a "hierarchy of controls" to select strategies for controlling hazards at school facilities.
According to the hierarchy, the best strategy to control a hazard is to systematically remove it, rather than relying on employees to do things that 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-to-least effective): engineering controls,
warnings, administrative controls, safe work practices, and PPE.
Elimination and Substitution
Elimination or substitution means completely eliminating or replacing a hazard to reduce risk. Reduce the risk of COVID-19 by having teachers, staff, and students stay home
when sick or if they have been in close contact with a person with COVID-19. Monitor COVID-19 transmission rates in the immediate community and the communities in which students,
teachers, and staff live. Work collaboratively with local health officials to determine if temporary school closure is necessary.
Engineering controls include isolating the exposure source and using local exhaust ventilation to minimize exposure to COVID-19. According to OSHA, this is the most effective control strategy. Examples include:
It is important to find ways to increase ventilation.Click to enlarge.
Increasing ventilation. Consider steps to increase the delivery of clean air and dilute potential contaminants. Not all steps are applicable for all scenarios.
- Increase outdoor air ventilation, using caution when outdoor air quality is low.
- Consider running the HVAC system at maximum outside airflow for 2 hours before and after school.
- Ensure restroom exhaust fans are functional and operating at full capacity when the building is occupied.
- Inspect and maintain local exhaust ventilation in areas such as restrooms, kitchens, cooking areas, etc.
- Consider portable high-efficiency particulate air (HEPA) fan/filtration systems to enhance air cleaning (especially in higher risk areas such as the nurse's office).
- Ventilation considerations are also important on school buses.
Click on the button to see OSHA's guidelines on the use of ventilation.
Ensuring adequate ventilation throughout the work environment can help to maintain a safe and healthy workplace. Employers should work with a
heating, ventilation, and air conditioning (HVAC) professional to consider steps to optimize building ventilation. An HVAC professional can ensure that the ventilation system is operating as intended. The following tips can help reduce the risk of exposure to the coronavirus:
- Encourage workers to stay home if they are sick.
- Ensure all HVAC systems are fully functional, especially those shut down or operating at reduced capacity during the pandemic.
- Remove or redirect personal fans to prevent blowing air from one worker to another.
- Use HVAC system filters with a Minimum Efficiency Reporting Value (MERV) rating of 13 or higher, where feasible.
- Increase the HVAC system’s outdoor air intake. Open windows or other sources of fresh air where possible.
- Be sure exhaust air is not pulled back into the building from HVAC air intakes or open windows.
- Consider using portable high-efficiency particulate air (HEPA) fan/filtration systems to increase clean air, especially in higher-risk areas.
- When changing filters, wear appropriate personal protective equipment. ASHRAE recommends N95 respirators, eye protection (safety glasses, goggles, or face shields), and disposable gloves.
- Make sure exhaust fans in restrooms are fully functional, operating at maximum capacity, and are set to remain on.
- Encourage workers to report any safety and health concerns.
If you are feeling sick, it is important to stay home.
Warnings such as signs, barrier tape, and alarms help employees become aware of hazards. In most hierarchy of control models, warnings are included with administrative controls. It’s also
important to know that warnings do not prevent exposure. They only warn students and others that a hazard exists. Warnings are only useful if they are not ignored.
Administrative controls and safe work practices include policies, procedures, training, and appropriate cleaning and disinfection practices. Good housekeeping practices should be used to help prevent
surface contamination and hygiene facilities and practice to protect workers from exposure.
Important administrative controls include:
Schools Support the Whole Child
Implement social distancing measures and cohorting.Click to enlarge.
K-12 school administrators may consider strategies to:
Protecting Staff at Higher Risk
Consider strategies for protecting staff at higher risk for severe illness.Click to enlarge.
Consider strategies for protecting staff at higher risk for severe illness.
- Offer options for staff at increased risk for severe illness from COVID-19 (e.g., telework, virtual teaching opportunities, modified job responsibilities, or temporary reassignment to different job responsibilities). Administrators may also consider extending these options to staff with a household member at a higher risk of severe illness if exposed to COVID-19.
- Investigate reasonable accommodations that could offer protection to an individual whose disability puts them at greater risk from COVID-19. Some accommodations may meet an employee's needs temporarily without causing undue hardship on the employer. The U.S. Equal Employment Opportunity Commission (EEOC) has established guidelines regarding Pandemic Preparedness in the Workplace and the Americans with Disabilities Act. The guidance enables employers to take steps to protect teachers and staff, consistent with CDC guidance.
- Consistent with applicable federal, state, and local law, put in place policies to protect the privacy of people at higher risk for severe illness due to underlying medical conditions.
Educate and train K-12 staff about how they can reduce the spread of COVID-19. Click to enlarge.
Educate and train K-12 staff about how they can reduce the spread of COVID-19. Training should be provided to all staff, including substitute teachers and other temporary personnel. Communication and training for staff should be easy to understand and be provided in languages other than English, as needed. Training should also be accompanied by necessary instructional materials in accessible formats, as required, and include information about:
- symptoms of COVID-19, how it spreads, risk for exposure, and different risk levels
- proper handwashing practices and use of hand sanitizer,
and cough and sneeze etiquette
- infection control precautions (e.g., putting on or taking off masks, social distancing measures)
- procedures to follow when an employee becomes sick or is exposed to someone who is potentially sick
- workplace hazards and ways to minimize exposure without compromising cleaning and disinfection.
OSHA provides additional information about training on its COVID-19 webpage.
Cleaning and Disinfection
There are several things to do when cleaning and disinfecting surfaces in K-12 school work areas.Click to enlarge.
There are several things to do when cleaning and disinfecting surfaces in K-12 school work areas.
- Consult general CDC guidance for cleaning and
disinfecting worksites, which may help guide planning for COVID-19 disinfection.
- Refer to List N on the U.S. Environmental
Protection Agency (EPA) website for EPA-registered disinfectants that have qualified under EPA's emerging viral pathogens program for use against SARS-CoV-2.
- Reduce the risk of asthma among staff and students
and health effects related to disinfecting by selecting
less-toxic disinfectant products on list N with asthma-safe ingredients (e.g., citric acid or lactic acid). Review the
NIOSH/OSHA Information sheet protecting workers who use cleaning chemicals.
Vapors from cleaning products can linger long after being applied, which can
exacerbate asthma symptoms and expose students and staff to potentially harmful substances.
- Follow label directions for appropriate dilution rates and contact times.
- Provide staff training on chemical hazards and manufacturer's directions.
- Minimize exposure to cleaning and disinfectant chemicals without compromising disinfection. Consider steps, such as:
- Use pre-mixed (ready-to-use) cleaning and disinfectant products instead of having to mix or dilute product.
- Use enclosed mixing/diluting dispenser systems to accurately mix products and minimize exposures.
- Avoid using spray products to clean surfaces such as mirrors and windows, using wipes or pre-soaked rags instead.
- Use containers/buckets with lids to store cleaning wipes/rags or product, and keep lids closed when not cleaning surfaces.
- Read and follow all instruction labels to ensure
safe and appropriate use. Do not use stronger concentrations than recommended. They will not be more effective and could exacerbate asthma and other
chemical-related health conditions.
- Establish a written protocol for the increased cleaning and disinfecting of all areas, such as restrooms, locker rooms, office work areas, cafeterias, break areas, and common spaces.
- Frequently clean push bars and handles on any doors that do not open automatically and handrails on stairs or along walkways.
- Frequently clean physical barriers (if used).
- Ensure staff keep cleaning and disinfectant products out of children's reach and stored in a space with restricted access.
Personal Protective Equipment (PPE)
CDC recommends people wear masks in public settings and when around people who don't live in the same household.
CDC recommends people wear masks in public settings and when around people who don't live in the same household, especially when other social distancing measures are difficult to maintain.
- Appropriate and consistent use of masks is most important when students, teachers, and staff are indoors and when social distancing is difficult to implement or maintain.
- Individuals should be frequently reminded not to touch the face covering or mask and to wash their hands or use hand sanitizer frequently.
- Information should be provided to staff, students, and students' families on proper use, removal, and washing of masks.
- People who are hearing-impaired, or care for others who are hearing-impaired, may be unable to wear masks if they rely on lipreading to communicate. To improve communication
if a mask blocks your lips, communicate in writing, and decrease background noise.
- In addition to those who interact with people who are deaf or hard of hearing, the following groups of teachers and staff may also consider using clear masks:
- teachers of young students (e.g., teaching young students to read)
- teachers of students who are English language learners
- teachers of students with disabilities
The CDC does not recommend using face shields for normal everyday activities or as a substitute for masks. They should only be used if standard masks are not available. There is a
lack of evidence that face shields effectively control the spread of the virus from the source. Here are some considerations for individuals who must wear a face shield instead of a mask:
- Face shield wearers should wash their hands before and after removing the face shield and avoid touching their eyes, nose, and mouth when removing it.
- Disposable face shields should be single-use and disposed of according to manufacturer instructions.
- Reusable face shields should be cleaned and disinfected after each use according to manufacturer instructions or by following CDC face shield cleaning instructions.
- Plastic face shields for newborns and infants are NOT recommended.
Click on the button below to see videos on how to put on and take off face masks and N95 filtering facepieces.
Transmission Risk in Schools
Analysis of pediatric COVID-19 hospitalization data from 14 states from early March to late July 2020 found the cumulative rate of COVID-19–associated hospitalization among children
was more than 20 times lower than adults (8.0 versus 164.5 per 100,000 population).
Although the cumulative rate is low, one in three children hospitalized with COVID-19 was admitted to an intensive care unit, so the risk is not negligible. Similarly, the death rate
among school-aged children is much lower than the rate among adults.
The risk of teachers, school administrators, and other staff in the school is expected to mirror that of other adults in the community if they contract COVID-19.
The best evidence from countries that have reopened schools indicates COVID-19 poses low risks to school-aged children – at least in areas with low community transmission.
Continuum of Risk
The risk of SARS-CoV-2 spread in schools increases across the continuum of virtual, hybrid, to in-person learning.Click to enlarge.
In general, the risk of SARS-CoV-2 spread in schools increases across the continuum of virtual, hybrid, to in-person learning.
While not exhaustive, this stratification from Operating schools during
COVID-19: CDC's Considerations attempts to characterize the risks of spread among students, teachers, and
staff across this continuum:
- students and teachers engage in virtual-only classes, activities, and events
- Hybrid Learning Model: Some students participate in virtual learning, and other students participate in in-person learning
- small, in-person classes, activities, and events
- leveraging all available safe community spaces, including outdoor spaces
- alternating schedules and staggered schedules are applied rigorously
- no mixing of groups of students (i.e., cohorts) and teachers throughout/across school days
- students and teachers do not share objects
- students, teachers, and staff always follow all steps to protect themselves and others, including proper use of face masks, social distancing, hand hygiene, and respiratory etiquette
- regularly scheduled cleaning and disinfection of frequently touched surfaces implemented consistently
- Hybrid Learning Model: Most students participate in in-person learning, some students participate in virtual learning
- larger in-person indoor classes, activities, and events
- cohorting, alternating schedules, and staggered schedules are applied with some exceptions
- some mixing of groups of students (i.e., cohorts) and teachers throughout/across school days
- students and teachers minimally share objects
- students, teachers, and staff follow all steps to protect themselves and others, such as proper use of face masks, social distancing, hand hygiene, and respiratory etiquette
- regularly scheduled cleaning and disinfection of frequently touched surfaces largely implemented consistently
- students minimally mix between classes and activities
- students and teachers share some objects
- students, teachers, and staff follow some steps to protect themselves and others at all times, such as proper use of face masks, social distancing, hand hygiene, and respiratory etiquette
- irregular cleaning and disinfection of frequently touched surfaces
- full-sized, in-person classes, activities, and events
- students mix freely between classes and activities
- students and teachers freely share objects
- students, teachers, and staff do not/are not required to follow steps to protect themselves and others, such as proper use of face masks, social distancing, hand hygiene, and
- irregular cleaning and disinfection of frequently touched surfaces
Risk in Youth Sports
The more people a child or coach interacts with, the closer the physical interaction, the longer that interaction, and the more sharing of equipment there is by multiple players,
the higher the risk of SARS-CoV-2 spread. The risk of spread of the virus that causes COVID-19 increases in
youth sports settings as follows:
- Lowest risk: Performing skill-building drills or conditioning at home, alone, or with family members.
- Increasing risk: Team-based practice.
- More risk: Within-team competition.
- Even more risk: Full competition between teams from the same local geographic area.
- Highest risk: Full competition between teams from different geographic areas.
For more information, see the
CDC's Readiness and Planning Tool for Schools.
OSHA has developed policies for enforcing OSHA's requirements for coronavirus as schools reopen. Click to enlarge.
The U.S. Department of Labor's Occupational Safety and Health Administration (OSHA) has adopted policies for enforcing OSHA's requirements for coronavirus as schools reopen in states
throughout the country.
As states begin reopening their schools, OSHA has issued two primary enforcement policies to ensure employers are taking action to protect their employees.
- OSHA is conducting in-person inspections at all types of workplaces. OSHA staff will prioritize COVID-19 inspections and will use all enforcement tools as OSHA has historically done.
- Under OSHA's recordkeeping requirements, coronavirus is a recordable illness, and school administrators are responsible for recording cases of the coronavirus, if the case:
- Is confirmed as a coronavirus illness;
- Is proven to be work-related as defined by 29 CFR 1904.5; and
- Involves one or more of the general recording criteria in 29 CFR 1904.7, such as medical treatment beyond first aid or days away from work.
OSHA will enforce the recordkeeping requirements of 29 CFR 1904 for employee coronavirus illnesses for all employers. The Emergency Operation Plan (EOP) should address recording
Given the nature of the disease and community spread in many instances, it remains difficult to determine whether a coronavirus illness is work-related, especially when an employee
has experienced potential exposure both in and out of the workplace. OSHA's guidance emphasizes that employers must make reasonable efforts to ascertain whether a particular case of
coronavirus is work-related.
For more information, see OSHA's COVID-19 standards webpage and
OSHA's COVID-19 Frequently Asked Questions.
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