The researchers - from Duke University and the Environmental Working Group, an advocacy nonprofit that wants to see better regulation of chemicals - tested the urine of 22 mothers and 26 of their toddler children for tell-tale chemicals signaling the presence of several flame retardants.
Not surprisingly, they found them.
All 48 had metabolites - the breakdown chemicals - of a flame retardant that has been linked to cancer and that was voluntarily removed from children's pajamas in the 1970s. Informally called "tris," it's still used in many other products, including upholstered furniture and crib mattresses.
Many also had breakdown products of a newer fire retardant, Firemaster 550, made by Chemtura Corp. of Philadelphia and touted as a more environmentally friendly chemical.
Both chemicals are replacements for yet another group of fire retardants known as PBDEs, which were removed from the market because they became ubiquitous in the environment and were found to be harmful to humans.
Seeing the PBDE replacements in people was worrisome to Duke researcher Heather Stapleton, who has studied flame retardants for more than a decade and participated in more than 60 published studies.
"While we knew a lot about PBDEs, we know very little about these new replacements," she said.
It is unclear what level of any of these chemicals will cause harm. But animal studies suggest even the newer ones can disrupt hormone systems and may cause cancer.
"Phasing out the use of toxic fire retardants, only to see them being replaced with chemicals that might be just as harmful is not progress," said Johanna Congleton, a senior scientist at the Environmental Working Group and lead author of the report.
The study results became even more troubling when the researchers compared the mothers with their children. In general, the toddlers had much higher levels. In the case of the tris metabolite, the average among the children was nearly five times the average of their mothers.
"It just reaffirms our hypothesis that this vulnerable population is receiving higher exposure," Stapleton said. The substances accumulate in household dust, so kids who crawl on the floor and put their hands in their mouths likely will ingest more of the chemicals.
What scientists need to figure out, Stapleton said, "is whether this level of exposure is related to an increased health risk."
The industry maintains flame retardants are not only safe, but necessary. They have been used in furniture nationwide because of a California law governing flammability standards. That law recently changed, and many manufacturers are phasing out the chemicals.
In response to the latest study, Chemtura director of innovation and sustainability Marshall Moore said the company was still evaluating it, adding, "we rigorously test our products to ensure the risk of health effects is low and the fire-protection benefits are real."
U.S. EPA assistant administrator for chemicals safety Jim Jones said the study shows why Congress needs to revamp the 1976 Toxic Substances Control Act, which even the industry considers outdated.
It puts the onus of chemical safety on the EPA, which must prove a chemical is not safe before banning it, rather than requiring companies to prove a chemical is safe.
"We're not even required to evaluate these compounds once they are on the market," he told the Chicago Tribune, which in a 2012 investigation found flame retardants often were not effective.
Wilson, who is pregnant with her second child, also would like to see the laws revamped. Although she and her daughter had comparatively low levels of the compounds, the results showed consumers can't do it all.
Most products are not labeled clearly, if at all. Plus, she noted, "even if our house was 'clean,' what about . . . my workplace, the library, friends' houses, and all the other places my daughter and I went?"
"There's only so much you can do," she said. "You have the rest of your life to lead. This is why I wish policy-makers would solve this problem."
"GreenSpace," about the environment and health, appears every other week, alternating with Art Carey's "Well Being" column.