Antibacterial compounds are no longer in your hand soap, but they’re in your floors, your walls, and in your body.
Just about two years ago, activists who work to reduce environmental contamination from hazardous chemicals were feeling pretty cheerful. After a struggle that had lasted decades, they’d persuaded the Food and Drug Administration to ban a slate of antibacterial chemicals from soaps and bodywashes in the United States.
The rap on the chemicals — especially the best-known and most common ones on the list, triclosan and triclocarban — was that hundreds of pieces of scientific research revealed they did more harm than good to humans and to the environment. Mouse studies suggested that these bacteria-killing compounds might affect hormone production and damage the microbiome, and they appeared to contribute to antibiotic resistance. Moreover, cleansers with these chemicals were no better at killing infectious bugs than plain soap and water.
The ban on triclosan and triclocarban was an achievement, given that the FDA had been mulling it over since 1974. But it was only a partial victory. Triclosan and triclocarban are still dosed into the carpets we walk on, added to the household plastics we handle every day, and blended into the caulk in our bathrooms and the paint on our walls. They are routine ingredients in fabrics and plastics — and thus in floor wax, air-conditioning coils, kitchen tools, and kids’ toys. Like a phone call in an old horror movie, triclosan and triclocarban are coming from inside the house.
Unlike hand sanitizers and soaps, all these products fall under the jurisdiction of the Environmental Protection Agency (EPA), rather than the FDA. And the EPA has so far shown no signs of cracking down on their use.
“There are thousands of products outside of the FDA’s regulatory reach that pose similar exposure and health threats,” says Rolf Halden, director of the Biodesign Center for Environmental Health Engineering at Arizona State University, who began researching triclosan in 2002. He estimates that more than 2,000 common products sold in the United States still contain the compounds.
Like a phone call in an old horror movie, triclosan and triclocarban are coming from inside the house.
Why dose your walls and carpets with antibacterials? To protect the objects themselves from attack by bacteria and mold, says Mae Wu, an attorney at the Natural Resources Defense Council, which helped bring about the FDA ban by filing a lawsuit against the agency in 2010. “It’s impregnated in all these products as a preservative.”
It might seem like a good thing to have walls that don’t harbor bacteria and spatulas that gunk won’t grow on. The problem, Wu said, is that the antibacterials don’t stay bound up in the materials they have been added to. As those household products wear and decay, the compounds escape and find other things in your house to cling to. “It ends up in household dust,” she says. “It’s coming off your bathroom caulk, or off the mousepad you just bought.”
It’s … everywhere
Last year, Halden and more than 200 other scientists detailed the ongoing threats related to these disinfectants in a scientific paper that has come to be known as the Florence Statement, for the location of the conference where it was drafted. The statement cites almost 170 pieces of research in order to document the persistent hazards of triclosan and triclocarban. The compounds flow into wastewater, pile up in sewage (and contaminate crop fields when sewage sludge is used as fertilizer), persist in the soil, accumulate in aquatic plants, and collect in the flesh of fish and livestock.
What’s more, a range of studies in the United States and in other countries have found traces of the chemical in human blood, urine, and breast milk. Over several decades, experiments in animals and observations in people show that in addition to interfering with hormone production, triclosan and triclocarban disrupt the endocrine system, damage heart muscle, affect the growth of fetuses, and may increase allergic reactions in children.
The compounds flow into wastewater, pile up in sewage, persist in the soil, accumulate in aquatic plants, and collect in the flesh of fish and livestock.
They may also contribute to one of the world’s most pressing health threats. Microbiologists have long suspected that triclosan’s ability to kill bacteria might create the same risks as the overuse of antibiotics. That is, a low or diluted dose might kill only the vulnerable bacteria, permitting bacteria that have developed defenses against the compounds to flourish and dominate. When that happens with antibiotics, the drugs became less and less useful as resistant bacteria take over. Antibiotic resistance kills an estimated 23,000 Americans and 700,000 people around the world each year.
In 2016, Halden and researchers from Harvard and the University of Oregon demonstrated that these disinfectants could make the problem of antibiotic resistance worse. They took samples of dust from indoor public spaces at their universities and subjected them to tests to reveal both the genetic and the chemical contents of the dust. The more triclosan there was in the dust, they found, the more antibiotic resistance bacterial genes the dust also contained. It suggests the disinfectant was influencing which bacteria survived and died. The alarming possibility: Triclosan may be changing the environmental microbiome and enriching it with bacteria that are potentially dangerous to human health.
Other recent work demonstrates how these compounds may be affecting animal microbiomes, setting up the possibility that they could do the same to us. Researchers at the University of Massachusetts fed triclosan to mice, so that they developed a blood concentration equal to what many humans already carry. Those antibacterial loads devastated the mice’s gut microbiomes, the mix of bacteria that help digest food, synthesize vitamins, and communicate to the immune system. The team reported in June that the mice that were fed triclosan experienced inflammation that could predispose them to other gut problems. In mice that had been engineered to have the equivalent of inflammatory bowel disease and colon cancer — conditions that many humans have — triclosan made those illnesses worse, with more cellular damage and larger tumors.
This precise effect had never been shown before. “We think our study suggests triclosan has previously unknown health risks,” says Guodong Zhang, the paper’s senior author and an assistant professor at the University of Massachusetts at Amherst.
To remove disinfectants, apply consumer pressure
Despite these emerging risks, it’s not at all clear that regulation of triclosan and triclocarban will change in the near term. The EPA last evaluated the chemicals in 2008. The agency usually reviews chemicals on a 15-year cycle but began another review of triclosan early, in 2013.
Since then, of course, the government has changed hands, and so has leadership of the agency. Trump’s pick for EPA administrator, Scott Pruitt, resigned in July after several ethics controversies, and the agency is currently headed by an acting administrator, a situation in which the EPA is unlikely to take any big steps. A spokesperson told NEO.LIFE that the agency expects to complete its review next year.
Some manufacturers are quietly changing their products’ formulas to phase out the problem chemicals without advertising they have done so.
With further policy changes unlikely, advocates hope the market will speak instead. Arlene Blum, the executive director of the Green Science Policy Institute in Berkeley — which won a multi-year battle to get toxic flame retardants removed from fabrics — thinks the way to reduce disinfectant use lies in targeting big purchasers such as car manufacturers, home builders, and huge retail chains.
“It’s really hard for the government — EPA, the FDA — to move quickly, but manufacturers and retailers can,” she says. “It’s not hard to motivate big buyers and trade associations when money is on the line.”
There is a precedent: Over the past four years, most poultry producers in the United States stopped routinely feeding antibiotics to their birds, largely because of consumer pressure from individuals and from big institutional buyers such as school systems and medical centers.
And there are subtle signs of change. The advocacy group Beyond Pesticides maintains a list of consumer products that contain triclosan and triclocarban. In some cases, the group says, manufacturers are quietly changing their products’ formulas to phase out the problem chemicals without advertising they have done so. Other manufacturers are explicitly embracing triclosan-free products: Halden is working with the Healthy Building Network, a research nonprofit that advocates for green and sustainable construction, to guide architects and materials manufacturers toward choosing components without these compounds.
If manufacturers stop adding triclosan and triclocarban to their products, the compounds in the environment now will slowly break down and disappear. As long as these chemicals aren’t replaced with some equally risky compound, the damage done by these antibacterials could finally become a thing of the past.