Synthetic chemicals added to consumer products to meet federal and state flammability standards are showing up in waterways, wildlife and even human breast milk.
Studies in laboratory animals and humans have linked the most scrutinized flame retardants, called polybrominated diphenyl ethers, or PBDEs, to thyroid disruption, memory and learning problems, delayed mental and physical development, lower IQ, advanced puberty and reduced fertility. Other flame retardants have been linked to cancer. At the same time, recent studies suggest that the chemicals may not effectively reduce the flammability of treated products.
The potential risks of flame retardants have been known for some time. In 1977, brominated tris was banned from use in children’s pajamas after researchers showed that it could damage DNA in animals. Two PBDEs, penta and octa, were pulled from the U.S. market in 2004. But another chemical that was removed from pajamas decades ago based on evidence that it could mutate DNA is still being used in furniture and some other baby products.
Flame retardants rely on chemical reactions that counteract or inhibit the flammability of treated products. Since the 1970s, they have been applied to textiles, foam in couches and baby products, building insulation, carpets, drapes, personal computers, TV sets, car dashboards, electrical cables and many other products.
The brominated and chlorinated flame retardants commonly found in consumer goods belong to a class of chemicals called semi-volatile organic compounds. Because they are not chemically bound to material but incorporated during manufacturing or sprayed on afterward, they routinely escape as vapor or airborne particles that tend to stick to surfaces or settle in dust. Friction and heat generated through normal use of a product — sitting on a couch, for example, or watching TV — can accelerate their release.
They can also escape during production or when treated products are recycled or disposed of in landfills or incinerators. Once released, they can build up in sewage sludge, soil and sediments. Scientists have detected flame retardants hundreds of miles from human sources, including in the tissue of sperm whales, which spend most of their time in deep ocean waters, and of Arctic marine mammals, suggesting long-distance transport by water and air currents.
Last year, Ronald Hites, a professor at the School of Public and Environmental Affairs at Indiana University, analyzed tree bark to track the spread of flame retardants in the environment worldwide. Tree bark, which soaks up chemicals in the atmosphere, has helped scientists document the presence of other persistent chemicals. He and Ph.D. student Amina Salamova collected bark samples from remote locations not associated with production or use of the chemicals on five continents, and flame retardants turned up in all of them, including a “very remote” region in Tasmania.
These compounds are building up in human fat, seminal fluid and breast milk. During the past 30 years, Hites reported in 2004, PBDE levels in human blood, milk and tissue increased by a factor of 100 — essentially doubling every five years.
The Centers for Disease Control and Prevention measured PBDE levels in people by analyzing blood samples collected in 2003 and 2004 for its National Health and Nutrition Examination Survey. The study found that 97 percent of Americans had flame retardants in their blood, and those ages 12 to 19 had the highest levels. It’s unclear what a safe level of exposure might be, if it exists. The CDC noted in 2008, when the report was released, that no human health effects had been directly attributed to exposure to PBDEs. But researchers say newer studies are concerning.
Federal standards first prohibited the manufacture and sale of dangerously flammable clothing in 1953. But it wasn’t until 1972 — when federal rules were put into place expanding the Flammable Fabrics Act to include children’s sleepwear, following reports that some kids’ pajamas burst into flames when children wandered near an open gas fire — that companies turned to flame retardants as a cost-effective way to meet the standards. Within a year, millions of parents were sending their kids to bed in pajamas treated with brominated tris.
In 1977, University of California at Berkeley biochemists Arlene Blum and Bruce Ames reported that the chemical posed a risk to human health. They found that brominated tris could damage DNA and was probably absorbed through the skin. That year, the Consumer Product Safety Commission banned its use in children’s sleepwear, noting that government studies showed that the chemical caused cancer in laboratory animals and confirmed that it could seep into skin.
The next year, Blum and Ames found that chlorinated tris, the chemical that had replaced brominated tris, also mutates DNA. Sleepwear manufacturers removed it from their products and switched to polyester and other fabrics that could meet the flammability test without using chemicals.
But federal officials did not ban chlorinated tris, and it continues to be used in other products. According to a report released by Blum and others in 2011, the chemical has been added to foam-filled infant changing table pads, nursing pillows, car seats and sleep positioners, among other products. It was also found in foam collected from sofa samples, along with a mixture called Firemaster 550.
In a preliminary study published last year, a team lead by researchers at Duke University and North Carolina State University reported that Firemaster 550 appears to be an endocrine disrupter that can cause obesity and advanced puberty in rats.
A spokesman for Chemtura, the Middlebury, Conn.-based company that makes Firemaster 550, said in an e-mail that its brominated component went through “extensive testing” before the product was introduced in 2003.
John Gustavsen, corporate communications manager for Chemtura, also noted that studies it provided to the Environmental Protection Agency before the chemical went into production relied on much larger sample sizes than the Duke/North Carolina State study and that those studies found no evidence of “extreme weight gain” even at much higher doses than the university researchers used. “We question the conclusions that have been attributed to what the authors themselves describe as ‘a small-scale study’, ” Gustavsen wrote.
Studies have shown that flame retardants collect in dust, which can then settle on hands and food. Research released last year linked the levels of flame retardants on toddlers’ hands with the amounts found in their blood.
Linda Birnbaum, director of the National Institute of Environmental Health Sciences and the National Toxicology Program, which are part of the National Institutes of Health, says, “For years, we’ve known that dust was a major source of exposure to lead, and we’ve ignored everything else that’s in dust.”
The largest study of children and flame retardants, led by Brenda Eskenazi, director of Berkeley’s Center for Environmental Research and Children’s Health, showed that children with higher exposures to PBDEs in the womb or during early childhood were more likely to score lower on tests assessing coordination, attention and IQ.
Meanwhile, recent studies from independent researchers and from scientists with the CPSC have raised questions about whether flame retardant applications provide any significant safety benefit in some consumer products.
Vytenis Babrauskas, a former head of the National Institute of Standards and Technology’s combustion toxicology program, led studies testing the effectiveness of flame retardants in furniture and building insulation. His furniture study found negligible differences between the combustibility of furniture made with treated and untreated foam. In both cases, he says, flame retardant concentrations are insufficient to make any meaningful reduction in hazard.
Since the beginning of the year, California and 12 other states — Connecticut, Illinois, Maine, Maryland, Massachusetts, Missouri, New Jersey, Nevada, New York, Oregon, Vermont and Washington — have considered bills to restrict the use of flame retardants.
So far, only the Maryland bill, which prohibits the sale of children’s products made with a form of chlorinated tris, has been passed by a legislature. The bill’s author, Del. James W. Hubbard, D, says he expects the governor to sign the bill within a month.
In February, 23 U.S. senators sent a letter urging the EPA to determine whether flame retardants in consumer products put Americans, and especially children, at risk, noting that the chemicals are “toxic, persist in our environment, and accumulate in our bodies” while failing to provide “significant protection against the risk of fires.”
Asked for comment for this article, the American Chemistry Council, which represents chemical manufacturers, said in an e-mail statement, “Flame retardants help products meet fire safety codes that are designed to provide protection from the effects of fires. Products containing flame retardants are tested to ensure they will pass established fire safety tests.”
“The discussion about toxicity in the [senators'] letter is misleading and implies that all flame retardants have toxicity concerns,” the trade group noted. “Any new fire safety chemical is evaluated for its safety and efficacy, and those evaluations are made available to government regulatory bodies before the product is used.”
In addition, the group offered: “We believe it is the role of the U.S. Environmental Protection Agency to determine if chemicals are safe for use. State chemical bans are not necessary and often in conflict with other jurisdictions.”
In March, the EPA announced that it will start evaluating the health and environmental risks of 20 flame retardants still on the market. ICL Industrial Products America, a major manufacturer of flame retardants, welcomed the EPA’s decision to review the chemicals’ safety.
“There has been an increased level of allegations about the concerns about the safety of flame retardants, often ignoring sound, peer-reviewed scientific studies and accepted regulatory assessments of the chemicals,” company spokesman Joel Tenney said in a press release. The EPA’s assessment, he added, would restore public confidence in flame retardants, which he said “meaningfully contribute to fire safety and save lives.”
As long as flame retardants remain in consumer products, Blum says, there are things people can do to can reduce exposure to the chemicals. She recommends washing hands frequently and regularly using a vacuum with a HEPA filter to keep dust down.
Foam-filled product with labels stating, “This article meets the flammability requirements of California Bureau of Home Furnishings Technical Bulletin 117,” probably contains flame retardants. Furniture and baby products made of polyester, down or wool are less likely to contain the chemicals.
In addition, these baby products don’t contain flame retardants, according to their manufacturers: BabyLuxe (organic) pads and mattresses, BabyBjorn carriers, OrbitBaby strollers and car seats, Boppy nursing pillows.
Blum says that since tris flame retardants were removed from children’s pajamas in the 1970s, more than 3,000 peer-reviewed studies have documented the ability of similar classes of flame retardants to accumulate or to harm health.
“We have more than enough research data to support not putting such potentially harmful compounds in furniture and other consumer products,” she says. “Especially when there’s no proven fire safety benefit.”
Flame retardants have been used in:
Pajamas (retardants no longer used)
Gross is a freelance science journalist in California.