Can killing germs be hazardous to your health? Questions about “quats”

“Millions of Americans use antibacterial hand soap and body wash products. Although consumers generally view these products as effective tools to help prevent the spread of germs, there is currently no evidence that they are any more effective at preventing illness than washing with plain soap and water,” wrote the US Food and Drug Administration (FDA) in issuing a proposed rule last month. “Further, some data suggest that long-term exposure to certain active ingredients used in antibacterial products—for example, triclosan (liquid soaps) and triclocarban (bar soaps)—could pose health risks, such as bacterial resistance or hormonal effects.” Because of these potential risks, FDA’s proposed rule requires manufacturers to demonstrate that their antibacterial personal care soap products are safe for long-term daily use and more effective in preventing illness and the spread of certain infections than plain soap and water.

But triclosan and triclocarban and the soap products mentioned in the FDA’s press release are far from the only antibacterial products in use. In fact, one industry analysis estimates the US market for disinfectant and antibacterial chemicals to be worth at least $1 billion annually and to be growing steadily, as it has been for the past ten years. Among the types of antibacterials whose use is growing most rapidly are quaternary ammonia compounds (quats). These compounds, of which there are many (a commonly used one  is benzalkonium chloride), are used in countless cleaning products – including everyday household cleaning products, liquid hand soaps, hand wipes and products used by professional cleaning services.

The increased use of antibacterial cleaning products has been propelled by increasing concern and anxiety about infectious disease, food-borne pathogens and healthcare-associated infections. “There are settings where there is a role for antimicrobials,” explains Elise Pechter, an industrial hygienist who runs the Massachusetts Department of Public Health’s Occupational Surveillance Program. But increasingly, questions are being raised about where and when it’s appropriate to use such disinfectants and when cleaning products without antibacterials might do the job just was well – and without undesirable side effects.

“We’ve become a germo-phobic society,” says Pechter. The public, she said, has increasingly become convinced “that a surface isn’t clean unless it is also disinfected.”

Consumer concern has focused on triclosan, an ingredient in many hand soaps, body washes, and other products. Scientific studies suggest that triclosan may interfere with hormones and can persist in wastewater. But quats, which may appear on product labels under many different names, have been of concern to those studying occupational health for some time.

Quats and asthma

Quats may not be getting as much media attention as triclosan, but a growing number of scientific studies conducted over the past ten years link exposure to quats with adverse respiratory effects, particularly for those who use them professionally. Epidemiological surveys of cleaning workers worldwide are consistently showing increased incidence and prevalence of asthma among cleaning workers, both those working in healthcare and non-medical settings, including homes. These studies also suggest that cleaning products can both prompt and exacerbate asthma. “There’s a pretty convincing body of evidence that they are asthmagens,” Pechter says of quats.

University of Massachusetts Professor of Work Environment Margaret Quinn, who has been studying the health effects of occupational exposure to cleaning products, explains that respiratory distress and irritation – both among people with previous asthmatic conditions and those without – are reported frequently. Some people exposed to cleaning products in healthcare settings have had reactions serious enough to warrant medical attention, with some visiting an emergency room.

A study of hospital workers in Belgium published in September found that the asthma symptoms experienced by a substantial number  of these workers in reaction to cleaning products were consistent with the respiratory effects produced by sensitizing asthmagens. This study concluded that quaternary ammonia compounds are the principal cause of sensitizer-induced occupational asthma among cleaning workers. This study is also the first to show how exposure to these cleaning products can change lung function and sputum (the mucus and saliva typically produced in response to a respiratory infection or irritation) and produce inflammation in internal airways.

Given the concern about infectious disease spread, including healthcare acquired infections, use of quats has become increasingly widespread – not only in medically sensitive locations but on floors and other hard surfaces public spaces. Quats, like many other antibacterial products, are classified as pesticides. Yet both Pechter and Quinn explained that there are no clear guidelines to help determine where disinfection with products that contain such pesticides should be used to prevent disease spread but at the same time protect those exposed to the products and the environment from any unwanted ancillary effects.

What’s also come to occupational health professionals’ attention is the fact that antibacterial cleaning products – including those containing quats – may not be clearly labeled to alert users to potential health effects and that cleaning products are often used in professional settings after being decanted into unlabeled containers. Pechter and Quinn also note that to be effective and actually kill germs as intended, these products need to be used according to directions, which doesn’t always happen.

Research needs

More research is needed, says Quinn to better understand the potential for infection to occur as a result of people touching hard surfaces previously touched by people carrying an infectious disease. More research is also needed to better understand how the widespread use of antibacterials may be contributing to the rise of such drug-resistant bacteria. There are also questions about the environmental and health effects of such widespread destruction of microbes and whether this might be contributing to the rise in allergies or other health disorders.

Another dilemma is the question of replacement chemicals.  Alexandra Scranton, science and research director at Women’s Voices for the Earth, points out that some products that had previously contained triclosan now contain a quaternary ammonia compound: benzalkonium chloride. This includes widely used liquid hand soaps commonly found on sink counters in offices, schools, restaurants and homes across the US. Quinn says more data is needed on replacement products – both antibacterial agents and alternate technologies, other ways of effectively killing germs when needed without adverse environmental and health effects.

Because they are considered pesticides, antibacterial agents like quats must be registered with EPA, which has extensive guidelines and requirements for determining their effectiveness in killing pathogens. What EPA does not require, however, is a test that would determine if these compounds or the products that contain them are asthmagens. The National Institute of Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA) have produced a fact-sheet and poster about health hazards of cleaning products, including respiratory hazards, but they do not include specific details about product ingredients apart from cautioning against mixing bleach and ammonia. (A NIOSH spokesperson explained that the agency’s work on this issue is ongoing.) The Department of Health and Human Services (HHS) has a database of cleaning product ingredients and health effects, but it includes only a fraction of the products that contain quats and a fraction of those that contain other potential asthmagens.

Meanwhile, as it’s becoming increasingly clear that quats are respiratory irritants that can induce or worsen asthma, they are also being used in an increasing number of products. Knowledge of health risks associated with quats should encourage them to be used  judiciously, especially as we don’t know enough about where we really need to be killing germs – and what the effects of eradicating 99 percent of most microbes present (as so many of these product promise) really are.

Elizabeth Grossman is the author of Chasing Molecules: Poisonous Products, Human Health, and the Promise of Green ChemistryHigh Tech Trash: Digital Devices, Hidden Toxics, and Human Health, and other books. Her work has appeared in a variety of publications including Scientific AmericanYale e360, Environmental Health Perspectives, Ensia, The Washington Post, Salon and The Nation. 


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The first time I saw an antibacterial product label that read "kills 99% of germs," my immediate reaction was, "...and lets the other 1% breed resistant strains, no thanks!"

I've never knowingly used modern antibacterials in my house: not for washing me, nor for household cleaning. Plain common soaps and detergents suffice for routine cleaning. Bleach is used for the "whites" in my laundry, and occasionally for nuking the kitchen sink, counter, and floor.

I use antibacterial soaps when I find them in public WCs in restaurants, because any hand-washing before eating is better than none. And I carry alcohol gel for use when there's no place to wash hands, such as after using a gasoline pump or ATM (major repositories of unpleasant bacteria).

As for asthma, I find it interesting that it's blamed on ambient tobacco smoke when smoking has declined so sharply in recent decades. Clearly that's an enemy-of-convenience when the real enemy is harder to locate. Living within 1/4 mile of a freeway is turning out to be a significant cause. Now if it turns out that quats are implicated, that will necessitate changes in work practices for professional cleaners.

Prediction: In about two decades we will have reached a point at which professional cleaners will need to have at least two years of college to deal with the range of chemicals and new technologies in their jobs. This will occur as a result of the further progression of emerging diseases and resistant strains, and recognition that sanitation is always the first line of defense in public health.

Excellent article. Elizabeth, I read your book Chasing Molecules. As an IH with a government agency, I find your article a real eye opener and a valuable reference. I had read about the concern from public health professionals about people, especially children, not developing resistance to common germ from too much use of antibacterial soaps. But this is the first time I read about occupational health concerns. I noticed that hand soaps sold at Wal Mart no longer say "antibacterial" but "Will wash germs away." It appears that the message is being heard and people like you, and those you quote in your article, are making a difference.

By Industrial Hygienist (not verified) on 12 Feb 2014 #permalink