Flame retardant in furniture poses danger, Duke study shows

Indications are growing that some of the most comfortable resting places in your home – your couch, your bed’s mattress – could be a health hazard.

A study by Duke University and the Washington, D.C.-based Environmental Working Group found evidence of exposure to a potentially harmful fire retardant in the urine samples of all 22 mothers and 26 children tested. On average, the children had nearly five times more than their mothers of a chemical formed when the fire retardant, TDCPP, breaks down in the body.

TDCPP – a primary focus among the chemicals studied – is often present in the foam used to make sofas, pillows, mattresses and carpet padding, among other household items. California has declared TDCPP a cancer-causing agent and includes warnings on all products using it and selected other chemicals. The Consumer Product Safety Commission lists TDCPP as a probable human carcinogen.

“The general population of the U.S. has constant, chronic exposure to these chemicals,” said Heather Stapleton, assistant professor of environmental chemistry at Duke’s Nicholas School of the Environment. “In some homes, it’s a much higher concentration than in other homes” – depending on myriad factors including the house’s size and ventilation rates, where the furniture was bought and what kind it is, and the type of home insulation.

“We focused on four or five flame retardants in this study (including TPhP, ip-TPhP and EH-TBB), but there are actually dozens if not hundreds of flame retardants out there,” she said. “They’re also used in electronics, cars, planes and more.”

For years, research and debate have been reported on the potentially harmful aspects of these chemicals. But the Duke/EWG study, published last month in Environmental Science and Technology, is the first to investigate children’s exposure to a newer class of fire-retardant chemicals. (PBDE, a class of common flame retardants, was associated with neurodevelopmental problems in children and was phased out over the past decade.)

Ellen Cooper, a Duke research scientist, said the project’s mission is that “consumers can make more informed choices in purchases, regulators can better decide if and when any changes in regulations should be made, and researchers can better evaluate how people are exposed to these chemicals and begin to understand if there are any health impacts associated with that exposure.”

Helping consumers

Part of Duke’s educational outreach is a foam-testing website – – created by Stapleton’s lab in January. Consumers can send up to five small samples and have them tested for free.

“We got so many calls from the public about how to identify what chemicals may be in their furniture or baby products that with the help of a federal grant, Duke set up a service so that people can find out if TDCPP is in their sofas,” Stapleton said.

Cooper explained how the foam samples are prepared and run through mass spectrometers to identify the flame retardants. A small portion of the sample is weighed and placed in a test tube, and a known volume of solvent (dichloromethane) is used to extract the sample. The extract is then injected into the analytical instrument to collect mass spectral data.

“Results from the analysis are compared against a library we prepared of spectra of known flame retardants. When a flame retardant is detected, we compare it to a standard to assess if the compound is above a 1 percent by weight threshold. This helps indicate that the compound was added to the product on purpose, as a flame retardant, and is not simply an unintentional contaminant.”

Cooper is also creating a database of collected samples. Part of the project’s challenge is determining how levels of flame retardants in furniture have changed over time.

Questions ahead

That’s one of many challenges and questions. Perhaps the largest unknown is the long-term effect of these chemicals on humans. Johanna Congleton, a senior scientist at EWG and collaborator on the project, said TDCPP “consistently causes tumors in animals in multiple sites.

“We do have some evidence from laboratory animal tests suggesting that these chemicals can disrupt the endocrine system. Proper hormone signaling is very important during critical windows of development and also during fetal development.”

It’s also unclear in which way humans’ exposure to the chemicals could be most harmful. Is it the breathing of the chemicals as they leach out over time and contaminate dust around us? Frequent, long-term contact with couches and pillows?

“It could be all of those. We just don’t know,” Stapleton said. “Each type of flame retardant has different types of properties, different behaviors. 

“We’ve shown for other flame retardants that in toddlers specifically, most of their exposure comes from putting their hands in their mouths. This either comes from contact with dust particles in the home that are contaminated, or from directly touching these products. With this new class of chemicals, it’s just not clear. We actually have a big research study under way right now to answer that question.”

Working with companies

Cooperation from furniture and chemical companies can help. Stapleton said many furniture companies “have been very receptive in trying to work with us so that we can help them help identify what’s in their supply chain.”

Joel Tenney, director of advocacy for Israel-based ICL Industrial Products – a major producer of fire retardants – talked about leveraging the latest scientific data to make “better materials choices.”

“A good example of that is the current trend to replace additive flame-retardant materials – like those measured by Dr. Stapleton – with reactive or polymeric ones in applications with more direct consumer exposures, such as polyurethane foam cushioning used in upholstered furniture. Reactive products become part of the substrate and polymeric materials, being larger, become more interconnected. Both types of solutions potentially eliminate exposure as a result of migration or physical wearing of the product.”

Tenney added: “Flame retardants are put through a battery of health and environmental tests before they reach the market, and that data is reviewed by appropriate regulatory bodies.” He said ICL-IP provides information to authorities such as the U.S. Environmental Protection Agency and Environment Canada, which evaluate and regulate how fit these materials are for commercial use.

But Stapleton said that under the EPA’s Toxic Substances Control Act of 1976, “If a flame-retardant manufacturer wants to market a new flame retardant, they can go right ahead and do so without testing it for toxicity beforehand. All they have to do is tell the EPA ‘I’m producing this chemical’ and under what volumes, and how I’m going to use it.”

The information is “confidential, and the EPA is not allowed to release it to anyone. So academic scientists, if they want to do any kind of research on the replacements, have no way of identifying what the replacements are unless you do what I’m doing and you go out and take samples of these products and spend a lot of money and a lot of time and try to determine what’s in there.”

Congress has attempted to change current guidelines. “But chemical manufacturers are reluctant to change to more strict regulations,” Stapleton said. “For furniture, the making of these chemicals is a billion-dollar industry. It’s very political.”

As of mid-September, efforts to come up with a new chemical regulation bill were struggling in the U.S. Senate.