Perhaps unsurprisingly, disinfectant use increased during the pandemic. Perhaps more startling, harmful chemical exposure increased along with it.

A new study released on May 8 found that the use of cleaning agents containing quaternary ammonium compounds (QACs), or “quats,” increased since the onset of COVID-19. Exposure to QACs can present a variety of health risks, although the extent of these risks is understudied and largely unknown.

Arnold WA, Blum A, Branyan J, et al. Quaternary ammonium compounds: A chemical class of emerging concern. Environmental Science & Technology. Published online 2023. doi:10.1021/acs.est.2c08244

According to the study, “[s]uspected or known adverse health outcomes include dermal and respiratory effects, developmental and reproductive toxicity, disruption of metabolic function such as lipid homeostasis, and impairment of mitochondrial function.”

“It's no surprise then that during and following a global pandemic, the use of disinfectants, and therefore quats, would increase,” says Homer Swei, Ph.D., EWG’s Senior Vice president of Healthy Living Science. They are also used in agricultural products like herbicides. “But the higher the use of quats, the higher also is the safety risk on people and the environment.”

What are Quaternary Ammonium Compounds (QACs)?

They share “similar characteristics” to per- and poly-fluoroalkyl substances (PFAS), which have been sparking conversation lately for their long-lasting and, in some cases, devastating health impacts. However, they “are less persistent than PFAS, and some are biodegradable,” Swei says. “The positive charge on quats tends to make them bind to soil and slide, making them less mobile and less persistent in water.”

Still, being less persistent doesn’t mean they are not at all persistent. Quats have been detected in both the body and the environment.

What are the health risks of quats?

About half of all the Environmental Protection Agency’s (EPA) approved disinfectants are quats, Swei adds. But, as exemplified by the other half of this list, cleaning agents don’t have to contain these chemicals to do their job, raising questions about whether the risks outweigh the benefits. 

“We may never know if quats had any meaningful impact on the spread of COVID-19,” says Swei. “But what we do know is that the indiscriminate use of quats increases the risk of antimicrobial and antibiotic resistance.”

He adds that primary health concerns linked to quats include:

• Their tendency to lead to antimicrobial resistance.

• Their “association with a multitude of aquatic and human health impacts, including ocular and ear damage, long-lasting irritation, contact dermatitis, and respiratory issues.”

• Their impacts on development, fertility, and cholesterol. (Some, but not all, quats have been linked to these risks, he adds).

The study also lists potential immune system, respiratory, and dermal effects. The authors note that more studies are needed to assess the risk profile fully and advise people on staying safe.

How to mitigate quat risks while staying clean

When faced with the current health risks of COVID-19 as well as the current risks of chemical exposures, winning one battle could mean losing the other.

As such, staying healthy on all fronts means weighing risks and benefits when purchasing and using cleaning products, says Rebecca Fuoco, MPH, the Director of Science Communications at Green Science Policy Institute. Risks posed by antimicrobial resistance may make this even more important in hospital settings, she adds. 

Purchasing products that are listed with an “A” score on the EWG's Guide to Healthy Cleaning database or that have EWG's verified cleaning products certification are good places to start, Swei says.