New worry for parents: Study by Berkeley science institute finds toxic substances in preschool carpets

woman standing in preschool playroom
Sue Britson, the executive director of Step One Preschool, has replaced the rugs that were found to have PFAS. Photo: Brett Simpson

As director of Step One Preschool on Spruce Street in Berkeley, Sue Britson tries to track all the toxics and pollutants to which her three to five-year-old charges might be exposed.

She keeps close tabs on the cleaning products the school uses to scour tables, floors, and chairs and to wash dishes and pans. She looks for the least-toxic paints and glues. Pesticides? Not used in the garden. Snacks? Preferably organic.

For up to $2,800 a month, families with children at Step One expect the best.

But in recent months, Britson has become aware of a new unexpected danger — in carpets.


A study that examined 18 preschools in the Bay Area found traces of per- and poly- flouroalkyl substances, or PFAS, in almost all of the preschools’ carpets. While 18 preschools participated in the study, Step One was the only school willing to make its participation public.

“Read a list of top ten questions to ask a preschool, and you’ll never see ‘what’s in the carpets?’” said Britson. “It wasn’t on any of our radars.”

PFAS are a class of manmade chemical compounds first developed in the 1950s by DuPont as the non-stick in Teflon pans. Today, they’re used in countless industrial and consumer products for their stain-resistant, grease-resistant, and flame-retardant properties. But research shows that long-term exposure to high levels of PFAS can be toxic, and still-developing children are especially at risk. This year, the state of California is tightening restrictions on PFAS in drinking water and considering a measure to ban sales of PFAS-treated carpets. But absent state or federal regulation, the sources of PFAS exposure are difficult to track, and not widely understood.

“The health risks for PFAS exposure are clear,” said Tom Bruton, senior scientist at the non-profit Green Science Policy Institute, whose scientists conducted the study along with others at the University of Indiana. “We wanted to contribute to a broader understanding of one source in our homes.”

Hundreds of laboratory studies link PFAS exposure to adverse health outcomes. Laboratory animals exposed to several classes of PFAS are more likely to develop liver, thyroid and pancreatic diseases, as well as changes in hormone levels, according to data from the U.S. Centers for Disease Control.

Multiple human epidemiological studies appear to corroborate those findings. The largest and most well-known of these followed a 2003 class-action lawsuit against the chemical manufacturer DuPont. After a West Virginia community faced decades of PFAS exposure in their drinking water from a DuPont plant, they received a multimillion-dollar settlement that they used to fund a health study on themselves.

The resulting 2013 C8 Study, carried out by researchers at Emory University, Brown University, and the London School of Hygiene and Tropical Medicine, collected blood samples from over 69,000 residents living in the area around the plant over the course of eight years. Their findings linked PFAS exposure to diseases like pregnancy-induced hypertension, high cholesterol, ulcerative colitis, and testicular and kidney cancer.

PFAS exposure comes from a variety of sources in our homes, including food packaging, nonstick pans, and waterproof clothes. The Green Science Policy Institute focused on carpets because of their proven effects on small children.

Arlene Blum, the founder of the Green Science Policy Institute, has combated exposure to toxic chemicals for decades as a research associate at the UC Berkeley Department of Chemistry. In the 1970s, her detections of flame retardants in children’s pajamas led to new federal regulations against the chemicals. In 2008, she founded the Green Science Policy Institute after learning that those same chemicals were back in use in couches and other household products. Now, her team conducts research to increase awareness about sources of toxic exposure in our environment. This year’s preschool study targeted a new threat to children’s health in homes: carpets.

In 2012, the U.S. Center for Disease Control reported that carpets are the number one pathway to PFAS exposure for infants and toddlers. Children spend much of their time on the floor and have frequent hand-to-mouth contact. And PFAS-treated stain-resistant carpets are often marketed directly toward parents because they require less frequent cleaning.

But once exposed to PFAS, research shows that small children bear outsized consequences. A 2012 University of Alberta bio-monitoring study that measured blood PFAS levels in a six-person Canadian household over the course of 15 years found that peak blood concentration of PFAS occurred in infancy and toddlerhood–in part because young children’s bodies are so small.

And children’s still-developing bodies are especially vulnerable to the chemical’s toxic effects. A 2017 review of 64 studies found a consistent relationship between PFAS exposure and adverse health outcomes in children, including compromised neurodevelopment and slowed immune response.

Britson estimates that children at Step One spend about 20% of their days on carpets. “We spend playtime, circle time, and nap time,” she said. “Carpets are just safer and cozier.”

kids asleep at preschool
Kids napping at Step One. Photo: Brett Simpson

On a Friday afternoon, children’s chatter fills the sunny playroom at the preschool. And where there’s a child, there’s a carpet: kids pile wooden blocks on a purple area rug, lie belly-first to scrawl in coloring books, and race up the nylon-lined ramp of an indoor play structure. At 2 p.m., as if on cue, teachers dim the lights, play wind chimes on the stereo, and arrange child-sized sleeping cots in neat lines in the center of the room — atop an expansive, fluffy green carpet.

Raja Antony, a father of two children who attend Step One, said that he had never heard of PFAS before the preschool participated in the study. And he said that even though he’s careful about toxic products, he still wants a clearer idea of the risks of PFAS exposure.

“Based on how little I hear about PFAS in the news, I’m not about to throw out all of the carpets in my house,” he said. “Maybe if I could see the impact clearly, this might be higher on the priority list.”

Last year, the California Department of Toxic Substances Control proposed listing PFAS-contaminated carpets as a “priority product,” which would ban statewide sales of carpets manufactured with PFAS. But it has yet to finalize the change.

In mid-October, the California Water Board released data showing elevated levels of PFAS in many California communities’ drinking water, some of which comes from surface water runoff from carpets dumped in landfills. Beginning in January, select California water utilities will have to monitor for the two most common types of PFAS, PFOA and PFOS, and notify the public of toxic levels for the first time.

Absent consistent regulations, some industries have taken action on their own. In September, The Home Depot announced they would stop selling carpets treated with PFAS by the end of 2019. Lowes issued a similar ban last month. Several food packaging, firefighting foam, and chemical manufacturers have also publicly banned PFAS from their products.

After conducting the preschool study, the Green Science Policy Institute gave each school a list of its contaminated carpets. Of Step One’s 16 carpets, the researchers found eight treated with PFAS. Based on this knowledge, Britson has replaced many carpets with wool alternatives. But she says that without clear labels, she can’t be sure if the new carpets are actually less toxic.

“We trust certain materials that seem more ‘natural,’ but we actually have no idea what’s in them,” she said. “It’s hard to tell parents there’s a problem without a clear solution.”

Bruton of the Green Science Policy Institute said that the preschool study’s findings introduced another complication: carpets in schools throughout the East Bay showed high levels of newly-developed, less widely understood variations of PFAS chemicals.

In 2008, chemical manufacturers like 3M began phasing out production of more traditional varieties of PFAS, such as PFOA and PFOS, that have been directly linked to disease. To replace them, they developed thousands of structurally similar alternatives. The health impacts of these new PFAS compounds are less clear. But new research, including a 2019 study from Auburn University, has found that at least some of these new varieties are as linked to biological harm as their predecessors.

“Industries are introducing thousands of these ‘regrettable replacements’ that are likely just as bad,” said Amy Kyle, a researcher at the UC Berkeley School of Public Health. “Scientists are playing a constant game of catch-up to prove that harm.”

Britson says that for busy preschools and their parents, clear proof might be necessary. She listed the myriad dangers that she already keeps close tabs on, such as cleaning products, paint, glue, plastics, and pesticides. She says that she has intended to discuss the study’s results more deeply with parents and other schools, but it’s taken a backseat to preparing for earthquakes and wildfires. At a certain point, she says, it will take a larger public reckoning to make PFAS a priority.

“Do we trust some products a little too much? Probably,” Britson said. “But we take our cues from the information we have, and so far the alarm bells aren’t loud enough.”

Antony agrees. “As a parent, there’s so much noise you have to tune out, or else you’re just being paranoid,” he said. “I’m going to ignore it for now. If it is significant enough, I’m sure I’ll hear about it.”

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