Deliberately blurred students in the background working on classwork. Hand sanitizer sanitiser pump with disinfectant spray bottle in the foreground. Corona virus Covid 19 education school theme.

Contributed by Darrel Hicks, the Co-Founder and Contributor for

A survey of 1,155 K-12 school staff were asked about their use of disinfectants to mitigate the spread of COVID-19 in schools. They reported frequent use of disinfectants, often using unknown products, and were provided little to no training on safe and effective use. Participant concerns included student involvement in disinfection, inadequate ventilation, surface contact time and potential health effects. 

According to the National Center for Education, the SARS-CoV-2 virus has greatly impacted 60 million U.S. children and school staff in K-12 classrooms since March 2020. To minimize the spread of COVID-19 in educational facilities, the Centers for Disease Control and Prevention (CDC) provided recommendations including disinfecting high-touch areas regularly with products on the Environmental Protection Agency (EPA) List N or a bleach solution. 

Disinfectants that kill SARS-CoV-2 are most commonly quaternary ammonium compounds (quats), bleach or peroxide based. Unfortunately, these products can carry the risk of skin and eye irritation, have been associated with asthma and chronic obstructive pulmonary disease (COPD) and contain chemicals linked to reproductive disorders, central nervous system impairment and cancer. For those reasons, warning labels on disinfectants state the need for ventilation, gloves and to keep children away.  

According to reports, vapors can remain in the air long after a surface is dry and chemicals such as quats leave residue after drying that can become a long-term exposure pathway via dust, particularly for children. In areas where these chemicals are used, the Environmental Protection Agency provided improved ventilation guidance to schools, such as opening windows and adjusting ventilation systems.  

However, many classrooms either don’t have windows or the windows they have don't open. Meanwhile, schools with older systems or limited resources may not be able to provide adequate ventilation and filtration.  

The lack of ventilation is a concern for many school occupants as the use of disinfectant chemicals has greatly increased since the start of 2020. One elementary teacher had this to say: “I’m in a windowless room, so I’m hoping that breathing in the [disinfectant] spray every hour will be okay long term.”  

Since the onset of the pandemic, teachers and other school staff have reported frequent use of disinfectants, most often without training or access to safety information. Half reported use of at least one product that is expected to kill the SARS-CoV-2 virus when “used according to the label directions.” However, these products have a “contact time,” typically 2-10 minutes, during which the surface must remain wet to be effective. Many teachers reported that the contact time exceeded the time between classes, so the product was wiped up early and therefore less or not effective.  

One teacher responded: “[It] is supposed to be left on the surface for a period of 10 minutes, but we were instructed to wipe it off immediately between classes.” 

In addition, children who may be particularly vulnerable due to their developing respiratory systems, were involved in disinfecting. Per the CDC, “disinfection products should not be used by or near children, and staff should ensure that there is adequate ventilation when using these products to prevent children or themselves from inhaling toxic vapors.”  

A high school teacher commented: “It says right on the label, ‘Keep away from children,’ yet teachers spray down every desk after each class and students wipe their desk (seven times per day) with cheap paper towels.” 

In addition to specific comments to questions, survey participants had the opportunity to provide additional information via open-ended questions. Most used this opportunity to express concerns, while only a handful of responses were positive.  

Here are some of the troubling comments from teachers who responded to the survey: 

“My classroom seemed to fill with the alcohol fumes after seven periods of cleaning between classes. That night I had continuing vomiting to the point where I went to the ER.” 

• “It is up to the teachers and students to clean, and I teach first grade.” 

• “After using products in the classroom, my asthma has been set off and caused two trips to the emergency room.” 

• “On the bottle, it says ‘Don’t use in food space’ but we have to use it to spray the kid’s desks before they eat lunch.” 

• “Some days my lungs hurt. I am afraid that someday in the future we will have problems with our lungs because of these products.” 

Clearly, a balance needs to be found between keeping students and teachers safe and the health effects of disinfectant use. As it became more evident that SARS-CoV-2 spreads more easily by air than by surface contact, the CDC updated its guidance to greatly reduce disinfection.  

It is prudent that K-12 school administrators follow CDC guidance regarding disinfectant use including frequency, ventilation, gloves, protection of children, and training teachers and staff. In addition, schools should select products found on the EPA List N which: 

• Have a contact time equal to or less than 1 minute. 

• Are safe as reflected in the HMIS (Hazardous Materials Identification System) score of 0-0-0. 

Ease of use is another consideration that should be used to evaluate disinfectants before purchasing. Products should be effective in the presence of environmental factors such as organic matter (i.e., blood), have an acceptable odor profile, be stable, be soluble in water, have simple directions for use and have good cleaning properties. 

Given the potential long-term health effects to school staff and children, following these guidelines will help ensure that disinfectant use in schools does more good than harm. 

J. Darrel Hicks, BA, Master REH, CHESP, holds a Certificate of Mastery in Infection Prevention (for Environmental Services Professionals), is the Co-Founder and Contributor for, and is the author of "Infection Prevention for Dummies."