By Kathleen Doheny
WebMD Health News Reviewed by Louise Chang, MD

Sept. 4, 2008 -- Young children have three times the blood levels of fire-retardant chemicals as their mothers, according to a new study by the Environmental Working Group. The chemicals are routinely used in common household items such as furniture, mattresses, and electronics.

The gap between mothers and their children was a surprise finding. Because of typically similar diet and exposures in the same household, "we would have expected similar levels," says Anila Jacob, MD, MPH, a senior scientist at EWG. "What we found was, kids on average had three times the levels of toxic retardants polluting their blood compared to their moms."

The chemicals are hormone-disrupting and potentially hazardous, especially to young brain development, Jacob and her colleagues say. But a spokesman for the flame retardant industry countered that the levels of chemicals, known as PBDEs or polybrominated diphenyl ethers, found in the study are quite low, in the parts per billion range.

Fire-Retardant Chemicals

The EWG scientists tested the blood of 20 U.S. children ages 1 to 4 and their mothers, and evaluated the samples for PBDEs. In 19 of 20 pairs, Jacob tells WebMD, the children had a higher concentration than the mothers.

Two types of PBDEs, Penta and Octa, are no longer made in the U.S., Jacob says, but are still present in older items in households. The researchers found that another PBDE, known as Deca, showed up in 65% of the children tested and 45% of the adults.

They found total PBDE concentration in the children's blood averaged 62 parts per billion and ranged from 24 to 114 ppb. The concentration in the mothers' blood averaged 25 ppb and ranged from 10 to 74 ppb.

There is no established standard for safe blood levels, according to Jacob and Sonya Lunder, MPH, a senior analyst at EWG and a co-author of the report. "These findings raise concern about the effect of PBDEs on children's brain development," Lunder says. "These levels are uncomfortably close to doses found harmful in laboratory animals.''

Although there are no human studies, Jacob and Lunder point to studies conducted by the Environmental Protection Agency (EPA) and others finding that PBDEs can be especially toxic to the developing brains of animals, with even a single dose of PBDEs causing ill effects.

In laboratory tests on mice, researchers have found that a dose of PBDEs given on a single day when the brain is growing rapidly can cause hyperactivity and other changes to behavior, the EWG researchers note.

In another study, done in lab rats, Deca was linked to cancers, according to a report from the National Toxicology Program.

The new report, the authors say, is the first to show that U.S. children have much higher levels of PBDEs in their blood than their parents. It comes on the heels of a study from Australia, published in late August in the journal Environmental Science and Technology, in which researchers tested the blood of more than 8,000 residents and also found that the children had higher levels of PBDEs than the parents.