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Antimicrobials

What are antimicrobials?

Antimicrobials are a class of chemicals used in many personal care and consumer products to kill or inhibit the growth of microbes. Antimicrobials of concern include halogenated aromatic compounds such as triclosan and triclocarban; nanosilver; and quaternary ammonium compounds (quats) such as benzalkonium chloride. These chemicals have biocidal properties when evaluated under lab conditions. However, there is little evidence supporting the benefits of antimicrobials in consumer products. Furthermore, common antimicrobials are toxic to aquatic life and are associated with adverse health impacts.

In September 2016, the U.S. Food and Drug Administration (FDA) determined that 19 different antimicrobial chemicals, including triclosan and triclocarban, were not effective and should not be marketed for use in over-the-counter consumer wash products. However, these and other antimicrobials are still permitted in numerous consumer and building products; and antimicrobial soaps containing other active ingredients are still widely available.

How are we exposed?

Antimicrobials are found in over 2,000 products, including:

People are exposed through direct contact with antimicrobial-containing products, and can also be exposed indirectly via dust, food, and water.

Properties of Concern:

Consumers may assume that added antimicrobials are beneficial, but there is little evidence to support the widespread use of antimicrobials in consumer products.

Antimicrobials may be needed in certain medical scenarios, and antimicrobial preservatives can be useful in certain applications (like water-based paints). However, the widespread use of antimicrobials in consumer and building products can have adverse effects on human health and the environment.

Lack of benefit:

Studies have shown that washing hands with plain soap and water is just as effective at preventing disease as washing with soap that contains antimicrobials.

In most cases, antimicrobial-containing consumer products have not been adequately evaluated to determine if they provide a meaningful improvement over other products. For instance:

  • A recent report on antimicrobial-treated hospital furnishings found little evidence that such products reduce the rate of healthcare-associated infections.
  • A recent analysis concluded that use of nanosilver in consumer textiles can have a range of ecological and environmental impacts. It identified significant research gaps preventing a clear understanding of the costs and benefits of such products.

Health risks:

Triclosan and triclocarban are associated with hormone disruption and reproductive and developmental impacts in animal and in-vitro studies Human epidemiological studies have linked exposure to certain antimicrobials including triclosan and quats to skin irritation, asthma, and allergies. There is also evidence that antimicrobials may harm beneficial gut bacteria. Antimicrobial chemicals have been found in urine, blood, and breast milk.

The long-term, non-specific use of antimicrobial chemicals in everyday products may contribute to the spread of antimicrobial resistance. For instance, bacterial communities can develop resistance to triclosan over time; and bacteria that develop resistance to triclosan have been shown to be less susceptible to other antimicrobials as well. Once pathogens become resistant to these chemicals, it is possible that more potent and more toxic chemicals will be needed to kill bacteria in serious medical situations.

Environmental concerns:

High-volume use of antimicrobials results in risks to the environment and wildlife. When products containing antimicrobials are washed, washed down the drain, or disposed of, antimicrobials can be released into aquatic environments where they can bioaccumulate in marine food webs. Triclosan, triclocarban, quats, and nanosilver are all toxic to aquatic organisms. Further, triclosan, triclocarban, and nanosilver are not broken down by wastewater treatment and persist in sludge that may later be applied to agricultural soil. During the wastewater treatment process, triclosan and triclocarban can react with other chemicals added for treatment to form toxic byproducts like dioxins and chloroform.

The Florence Statement on Triclosan and Triclocarban

The Florence Statement on Triclosan and Triclocarban documents the scientific consensus about health and ecological concerns and lack of benefit associated with the use of two common antimicrobial chemicals, triclosan and triclocarban. It also makes recommendations to prevent harm from other antimicrobials. It was signed by more than 200 scientists from 29 countries.
Learn more.

What can you do?

  • Avoid products that are advertised as “antimicrobial”, “antibacterial”, or “anti-odor”.
  • Soaps, body washes, toothpastes, and cosmetics will generally list antimicrobial chemicals on the ingredient label. You can also look up products on the EWG Skin Deep database.
  • Note that many personal care products are replacing triclosan and triclocarban with quats (e.g., benzalkonium chloride, benzethonium chloride) or other antimicrobial chemicals that have limited information on health impacts (e.g., chloroxylenol).
  • Tell manufacturers, retailers, and government agencies you want products without antimicrobials.

Resources

Antimicrobials in the Media