Popular COVID disinfectants raise concerns among scientists

The COVID-19 pandemic has boosted the unnecessary use of antimicrobial chemicals linked to health problems, antimicrobial resistance and environmental harm, more than two dozen scientists at Environmental science and technology.

Their critical review outlines how quaternary ammonium compounds (QACs) are increasingly being marketed and used in home, health care, education, and workplace settings despite the availability of safer alternatives and in some cases limited evidence of reduced disease transmission.

“Disinfecting wipes containing QACs are often used on children’s school desks, hospital exam tables, and in homes where they remain on these surfaces and in the air,” said Courtney Karinian, co-author and assistant professor at Michigan State University. “Our review of the science indicates that in many cases disinfection with these chemicals is unhelpful or even harmful. We recommend regular cleaning with soap and water and disinfection only as needed with safer products.”

Human studies have found associations between QACs and asthma, dermatitis, and inflammation. Lab animal studies raise concerns about potential links to infertility, birth defects, and more. Moreover, there was evidence as far back as the 1950s that QACs contribute to antimicrobial resistance, making some bacteria resistant to both QACs themselves and important antibiotics.

“Ironically, the chemicals we use in vain in one health crisis fuel another,” said Erica Hartmann, a co-author and professor at Northwestern University. “Antimicrobial resistance was already contributing to millions of deaths annually before the pandemic. Excessive disinfection, especially with products containing QACs, threatens to make it worse.”

QACs are increasingly being used in disinfecting solutions, wipes, hand sanitizers, sprays, and pumps, and are also being incorporated into personal care products, textiles, paints, medical instruments, and more. Since the pandemic, levels of these chemicals in the environment and our bodies have increased in parallel.

One of the most common QACs is benzalkonium chloride, but others can be identified on ingredient labels by names ending in “ammonium chloride” or similar. However, disclosure and regulation of quality control systems varies widely. For example, pesticide labels are required to list QACs but paint labels are not. Most QACs are not regulated at all, nor are they comprehensively screened for health risks.

Scientists recommend eliminating uses of QACs that are unnecessary or whose effectiveness has not been proven. For example, disinfection with QACs is often not as beneficial as cleaning with plain soap and water. Other recommendations include requiring full disclosure of QACs in all products and closely monitoring levels in people and the environment.

“Significantly limiting the uses of QACs will not spread COVID-19,” said Carol Kwiatkowski, co-author and scientist at the Green Science Policy Institute. “In fact, it will make our homes, classrooms, offices, and other common spaces healthier.”