Back in the day, it was thought that putting hazardous chemicals that killed bugs into architectural products like wallpaper was a good idea; that’s how we got DDT impregnated wallpaper for your kids’ room. We laugh at this now, but in fact manufacturers are still doing it; different chemicals going after different bugs, the the principle is the same.
So now, instead of DDT, companies are putting “microbials” onto appliances, surfaces and door knobs. Bill Walsh of Healthy Building News points to one company that claims:
“Nearly 7 out of 10 consumers are concerned about the presence of bacteria on the door handles and knobs in their homes and 8 out of 10 are interested in Microban product protection to help keep their door hardware cleaner. Microban antimicrobial product protection can provide an important benefit to your customers and valuable point of differentiation for your brand.
No evidence yet exists to demonstrate that products intended for use in interior spaces that incorporate antimicrobial additives actually result in healthier populations. Further, antimicrobials may have negative impacts on both people and the environment. Their widespread use may be associated with microbial resistance to these agents, and potentially to therapeutic antibiotics. Evidence is growing that antimicrobial additives can migrate from the products in which they are incorporated, finding their way into wastewater systems and the larger environment with unknown ecological implications, but with reasonable cause for concern.
There are many antimicrobials that may be problematic; some are known to the public now, like Triclosan. But others are still marketed as a big plus, like nanosilver, which we have seen in everything from food-wrapping paper to underwear. Now antimicrobials are showing up on door handles, light switches, carpets and paints. But they don’t work all that well and there is a bigger problem.
Antimicrobial resistant organisms are already being found for the additives discussed above. While not yet widely studied, antimicrobial resistance to silver-based additives has been reported in strains of Salmonella typhimurium, E. coli, and other bacteria, after exposure to antimicrobial silver in wound dressings. Microbes resistant to triclosan are also appearing. A recent study found the presence of triclosan in the body can actually promote Staph infections.
Perkins + Will conclude that there are few benefits to using antimicrobials; “In 2016, after studying the issue for four decades, the Food and Drug Administration came to the same conclusion: there is no evidence that antimicrobial additives provide an added benefit.” But there are many risks- “Potential impacts to human and environmental health as a result of these additives may include antibiotic resistance, and the appearance of antimicrobial additives in ecosystems.”
Bill Walsh of Healthy Building News likes what he sees here and has some good advice.
Evaluating and understanding the use of antibacterials in building products is confusing. Inadequate federal laws, regulatory loopholes, and a lack of transparency drive product development based upon consumer misunderstanding and fear, rather than evidence-based design. The new Perkins+Will policy is a good rule of thumb for the building industry: avoid, where possible, products containing added antimicrobial ingredients.
It is much like DDT impregnated wallpaper: you can only ask, “What were they thinking?”