In hopes of reducing the possibility of the transmission of COVID-19, many architects are likely considering materials that include antimicrobial treatments for projects that range from health care facilities to office renovations. But a just-released report indicates that designers should be cautious. Conducted by Perkins and Will, in collaboration with Healthy Building Network (HBN), a non-profit focused on chemical hazards in buildings, the document says that there is no evidence that using interior products and finishes incorporating antimicrobial additives result in healthier occupants. And it warns that these additives may have negative impacts on both people and the environment.

The findings are not new. COVID-19 Statement: Understanding Antimicrobial Ingredients in Building Materials confirms the conclusions of a more extensive whitepaper on antimicrobials that the architecture firm and HBN published in 2017. Mary Dickinson, co-director of Perkins and Will’s materials performance lab, explains that the reexamination was prompted by the firm’s clients and project teams who were clamoring for guidance in light of the pandemic. The goal, she says, is to maintain the latest report as a living document, updating it with new research and data on the virus and antimicrobials as they become available.

What is an “antimicrobial?” The term can apply to substances such as anti-bacterials, biocides, and pesticides, among others. They document explains that they may be necessary ingredients in some building materials as preservatives, protecting the products against decay and degradation from mold, fungus, or pests. But, says the statement, designers and specifiers should be wary of products or materials that make implied or explicit claims regarding human health benefits.

The report outlines the reasons for concern. Some antimicrobial substances are suspected carcinogens or respiratory sensitizers, and diseases such as cancer and asthma have been shown to decrease a person’s ability to fight COVID-19. The widespread use of such substances may also be associated with microbial resistance to these agents, and potentially, to therapeutic antibiotics. And, the document reports that evidence is growing that these additives can migrate from the products in which they are incorporated, finding their way into wastewater systems and the greater environment with unknown ecological effects. Arguably, equally worrisome: owners and building managers might feel inappropriately reassured by the inclusion of finishes with antimicrobial treatments. “They might relax cleaning and disinfection protocols, which could lead to more serious issues” and promote the spread of the virus, points out Max Richter, materials performance lab co-director.

In light of this information, what course of action should designers and clients concerned about virus transmission take? The report recommends avoiding products with antimicrobial additives that make disease control assertions and to instead specify alternatives that omit such treatments. “While there is a clear need for COVID-19 pandemic action plans,” concludes the document, “we must be cautious and inquisitive, follow the science, and ultimately provide building users with the necessary information to avoid a false sense of security.