It’s safe to say that none of us wants to have a serious battle with COVID-19, and to avoid it, we’re reaching for disinfectants in unprecedented amounts. If we’re not careful, though, we can cause ourselves and others health problems that are as potentially problematic as what we’re trying to avoid. Here are some things to know about disinfectants.
1. Cleaning and disinfecting work in different ways. Cleaning removes germs by washing them down the drain. Disinfecting kills them.
2. A sanitizer is similar to a disinfectant. The terms “sanitizing” and “sanitizer” are defined differently depending on who’s doing the defining. Sometimes sanitizing is used to mean the process of lowering the number of germs by either cleaning or disinfecting. Others use the term “sanitizer” to mean a disinfecting product designed for use on a person rather than a hard surface, and some say that sanitizers are for bacteria, while disinfectants also target viruses. Yet another definition is that sanitizers kill organisms, but that disinfectants kill both organisms and their spores.
3. Disinfectants are pesticides. A pesticide is a product designed to kill a living organism. A Texas A&M publication notes, “Pesticides that fight microbes are generally called antimicrobials. . . . About 275 active ingredients are found in antimicrobials, most of which are pesticides and must have an EPA-approved label.”
4. An EPA registration means the product should kill what it says it will. It doesn’t mean it’s been proven safe. This is from a publication entitled Green Cleaning, Sanitizing, and Disinfecting found on the EPA’s own website: “Many people mistakenly think that if a cleaning, sanitizing, or disinfecting product is sold to the public it has been reviewed and proven safe by government agencies. The U.S. Environmental Protection Agency (EPA) requires that products labeled as sanitizers or disinfectants do kill the germs that the product claims to kill, but the registration review does not evaluate all possible health risks for users of the products. Cleaning products are also not routinely reviewed by the government to identify health risks to the user. Some manufacturers choose to have the EPA evaluate their cleaning products for human health and environmental safety through the Design for the Environment (DfE) Safer Product Labeling Program, but this is voluntary and most products are not reviewed.”
5. Despite the fact that they aren’t rigorously tested, health effects associated with common disinfectants are becoming more widely known. Chemical and Engineering News published an article entitled “Do We Know Enough About the Safety of Quat Disinfectants?” Quats (quaternary ammonium compounds) are widely used in disinfectant products, but they’ve been linked to a number of potentially significant health issues which have been discovered “independently and also by chance.” These include the possibility of birth defects, fertility issues, and disruption of cellular processes.
Other disinfectant chemicals have their own problems. A publication entitled Safer Products and Practices for Disinfecting and Sanitizing Surfaces says this: “Although all of these ‘antimicrobial’ products have risks, there are a few types that pose greater, long-term risks to custodial workers and building occupants because they contain active ingredients that have been found to cause asthma (e.g., chlorine bleach/sodium hypochlorite, peroxyacetic acid, and quaternary ammonium compounds), cancer (e.g., ortho-phenylphenol), skin sensitization (e.g., chlorine bleach, pine oil, and thymol) or other health hazards. Several also pose environmental risks as well, such as silver and quaternary ammonium chloride compounds.”
6. It’s not just the people who use them who are affected. The Green Cleaning publication speaks to the issue of workplace asthma tied to cleaning and disinfecting products. The authors note that 80% of those affected were bystanders who weren’t working directly with the chemicals, but were simply near enough to be exposed to them.
7. Disinfectants can cause health problems both through inhalation and skin exposure. Disinfectant chemicals, especially quats, tend to accumulate on surfaces. They can then be absorbed through the skin and enter the bloodstream. In an article on chemical exposures in the workplace, the CDC notes that absorption of chemicals through the skin may be the most significant route of exposure in some cases, and that cleaners are among the workers at risk.
For children in particular, the route may be more direct because chemicals end up on hands, and hands end up in mouths. In an “Ask the Professor” column, the authors state that this can lead to intake that’s more than 2,000 times higher than normal. For some disinfectant chemicals, a 3-year-old takes in 55 times more than an adult does.
8. Disinfectants can’t get to germs on a surface to kill them unless the surface has been cleaned. This has been described as trying to vacuum the floor without picking up the toys and clothes there first.
9. If a surface has been well cleaned, it may not need to be disinfected. An environmental expert noted that more than 90% of microorganisms on a surface can be removed with soap, water, and a microfiber cloth, which is potentially more effective than using disinfectants on a surface that hasn’t been cleaned. He said, "You always want to be balancing risks and benefits, and you want to be using the safest products possible in the safest way possible. You could use a grenade to kill a fly, but a fly swatter will work just as well and cause far less damage." A guide to safer disinfectants notes that the FDA banned 19 antimicrobial ingredients from soap in 2016, because plain soap and water without the disinfectant chemicals were found to be just as effective.
10. Disinfectants may not be as important in the fight against sickness as we seem to think they are. A publication on talking to your child’s school about using safer products mentions a study which measured bacteria on children’s hands and on classroom surfaces. The researchers found that the amount of bacteria on hands was associated with how often kids got sick with colds or flu, but that the amount of bacteria on surfaces wasn’t a factor. The same publication notes, “There is no evidence that shows using disinfecting wipes, sprays, or antibacterial soaps are any more effective at preventing illness in the classroom than washing with regular soap and water.” Regarding COVID-19 in particular, the Centers for Disease Control says that “it may be possible” to be infected through touching a surface, but that it isn’t thought to be a primary route of transmission.
11. The focus on surface disinfection may distract us from what actually works. An article in The Atlantic calls the widespread use of disinfectants “hygiene theater” and provides this observation: “Establishments are boasting about their cleaning practices while inviting strangers into unventilated indoor spaces to share one another’s microbial exhalations. This logic is warped. It completely misrepresents the nature of an airborne threat. It’s as if an oceanside town stalked by a frenzy of ravenous sharks urged people to return to the beach by saying, We care about your health and safety, so we’ve reinforced the boardwalk with concrete. Lovely. Now people can sturdily walk into the ocean and be separated from their limbs.”
12. Disinfectants are often used improperly. Like other pesticides, there are safety laws that govern how they’re used. The Texas A & M article points out that instructions on disinfectant labels aren’t just suggestions. They say, “Using even a little more disinfectant than the label allows in a cleaning solution, or failing to wear the proper safety gear specified on the label, to give two examples, is a violation of state and federal pesticide laws.”
Many establishments are using sprayers, misters, or foggers to apply disinfectant products, which often doesn’t meet label requirements. The World Health Organization warns that spraying or fogging disinfectants “will not be effective and may pose harm to individuals.”
Many people are especially concerned that students in school settings are being given disinfectant wipes for cleaning their own desks. The EPA warns against this, pointing out that labels on disinfectants all say “Keep Out of Reach of Children.”
13. Their use can lead to stronger, medication-resistant germs.
Benzalkonium chloride (BAC) is one of the most common active ingredients found in disinfectant products, including wipes and antibacterial soaps. Researchers have found that when bacteria is exposed to low levels of BAC, its tolerance can increase up to 500-fold. Microbial resistance is especially likely to develop when disinfectants are used improperly, such as on a surface that hasn’t been cleaned first.
14. All disinfectants are not created equal. Some ingredients are much more problematic than others. A quick way to gauge the relative toxicity of a commercial disinfecting product is to look at the “signal word” on the label. It will say either “Danger,” “Warning,” or “Caution.” The products with a “Danger” label are thought to be the most toxic, and those that say “Caution,” the safest. Within each category, there are products with varying degrees of safety.
Commercial disinfectants are generally mixtures of many different compounds, so even if the first ingredient listed is considered safe, the product as a whole may not be. Fragrances are commonly added to disinfectant products, and they add many chemical hazards without increasing effectiveness in any way.
Remember that you may not need a disinfectant at all if you clean surfaces well (especially with a microfiber cloth), and if you do decide you need one, there are time-tested options. As one expert in environmental chemicals notes, “Hydrogen peroxide, citric acid, or octanoic acid are safe and effective,” and they’re all listed by the EPA as effective against the virus that causes COVID-19. In fact, research finds hydrogen peroxide-based disinfectants to be more effective than quat-based products.
Microbes can certainly cause problems, and so can antimicrobials. I pray you’ll stay safe from both.