Growing Concerns About the Overuse of QACs

Ever since the pandemic, there has been an increased focus on cleaning, sanitizing, and disinfecting indoor spaces. Overall, this attention on improving cleaning protocols is positive. After all, we do want to keep our living and workspaces safe using the latest and greatest cleaning technologies. However, what we clean with is just as important as how we clean. Recently, the scientific community has raised concerns over the use of Quaternary Ammonium Compounds (QACs). QACs define a broad class of chemicals originally developed for industrial strength cleaners and disinfectants. Prior to the global pandemic, these chemicals were used more sparingly in industrial settings. However, in recent years, QACs are now used universally throughout public spaces such as schools and even homes. Additionally, QACs are now the active ingredient in approximately 50% of the EPA’s List(N) approved disinfectants.

The use of large-scale foggers and sprayers during the pandemic has also greatly increased our exposure to QACs. In a recent study published in the journal of Environmental Science & Technology titled Quaternary Ammonium Compounds: A Chemical Class of Emerging Concern,1 researchers conducted a thorough analysis of the existing literature on potential harms of long-term exposure to QACs. Their findings are quite alarming.

Man in PPE pours chemicals containing QACs or Quats demonstrating the overuse of QACs

The researchers’ main concern is the widespread and growing use of QACs without a proper understanding of their long-term consequences on humans. The authors argue that greater and long-term use in indoor environments—especially workplaces and schools —are causing health problems and will undoubtedly lead to severe, chronic health problems in the future.

Respiratory Issues

The authors cite human studies that have looked at the respiratory issues caused by QAC-based cleaners. They note that QACs can become aerosolized and lead to breathing problems—even for those without preconditions. They write, “in a prospective cohort study of female nurses in the US, high-levels of exposures to disinfectants and cleaning products, including QAC-containing items, were significantly associated with increased risk of chronic obstructive pulmonary disease, independent of asthma and smoking status.” As noted earlier, the increased use of foggers reduces air quality and can make pulmonary symptoms worse.

Potential Reproductive Harm

The authors also outline early evidence to suggest that repeated exposure to QACs can lead to potential reproductive harm. They write, “reproductive toxicity in mice was accidentally discovered when unexpected infertility was traced back to use of a vivarium cleaning product… Reproductive effects were identified for both males and females.” It is still unclear whether QACs can cause similar harm in humans, but the trend in mice should be of concern.

Harm to Vulnerable Populations

Another area that the authors highlight is that vulnerable populations such as children are at risk. Over the past few years, QACs have seen increased use in schools. Cleaners containing QACs often leave residue on surfaces, and because children have much more hand to mouth contact, they are at higher risk of ingesting these dangerous chemicals. Additionally, the authors cite research showing QACs present in breast milk which can put newborns at risk early in life.


Studies show that certain types of QACs have extended half-lives of months and even years and persist on surfaces, in water, and in soils much longer than previously thought. As a result, higher concentrations of QACs were found in both waters and soils, leading to ongoing environmental concerns.

Anti-microbial Resistance

In 2019 over 5 million deaths were attributed to anti-microbial resistance. QACs, when overused, used improperly, or used in insufficient strength to kill harmful microorganisms, lead to anti-microbial resistance. Studies have even shown that cleaning residue containing weakened QAC chemicals can even become food for microorganisms, leading to further resistance.

The Bottom Line

QACs increased use in the workplace, schools, and medical settings should concern us. The authors of this study have made it abundantly clear that, at least, more research into the topic is necessary. The overuse of chemicals has become a serious issue over the past few years, and we should reconsider the effectiveness of chemicals when there are clearly safer and better alternatives. Solutions such as aqueous ozone and powerful UV lights have comparable results to toxic chemicals without the harmful residue or negative health effects. We all agree that indoor cleaning is essential, but if we choose to keep using harmful chemicals, we risk creating a public health crisis in the future.

Common Products That Contain QACs

Common household products containing QACs from the EPA's List N Disinfectants for Coronavirus.
  1. William A. Arnold, Arlene Blum, Jennifer Branyan, Thomas A. Bruton, Courtney C. Carignan, Gino Gortopassi, Sandipan Datta, Jamieu DeWitt, Anne-Cooper Doherty, Rolf U. Halden, Homero Harari, Erica M. Hartmann, Terry C. Hrubec, Shoba Iyer, Carol F. Kwiatkowski, Jonas LaPier, Dingsheng Li, Li Li, Jorge G. Muniz Ortiz, Amina Salamova, Ted Schettler, Ryan P. Seguin, Anna Soehl, Rebecca Sutton, Libin Xu, & Guomao Zheng (2023) Quaternary Ammonium Compounds: A Chemical Class of Emerging Concern, Environmental Science & Technology, DOI: 10.1021/acs.est.2c08244
Posted in Article, Cleaning and Disinfecting, Consumer, GSS News.