Preventing fires, igniting questions
The findings persuaded Sweden to ban penta and octa, and the European Union began scrutinizing them. That got the attention of Hooper and his colleagues, whose California lab decided to analyze fat tissue--where PBDEs accumulate--from women in the San Francisco Bay area. The women had levels 6 to 10 times as high as women in Europe, where the compounds are used more sparingly. Other studies have found levels 20 times as high.
Researchers are only now figuring out how most PBDEs move out of products and into people. Miriam Diamond and her colleagues at the University of Toronto took samples of grime coating windows and found the highest concentrations indoors, in the city. She thinks PBDEs waft out of plastics and furniture indoors and stick to dust particles that people breathe and swallow. Several studies, the latest coming out this month from the Environmental Working Group, have found high concentrations in house dust. "It raises questions about babies crawling around engaging in hand-to-mouth activities," says EWG's Sonya Lunder, an environmental analyst. PBDEs also migrate outdoors, ending up in waterways and in some fish.
Meanwhile, other worrisome hints have emerged from the lab. "We've seen that the commercial penta mix delays puberty and affects the developing testes in rats," says Linda Birnbaum, a toxicologist at the Environmental Protection Agency's National Health and Environmental Effects Research Lab in North Carolina.
Last year, state governments began taking action against penta and octa. And in November, the Great Lakes Chemical Corp. of West Lafayette, Ind., the largest U.S. maker of the two chemicals, said it would end production. That leaves deca, which has been promoted as the safest PBDE--unlikely to escape from products or get taken up by organisms because its molecules are bulky. "Deca does not pose a risk to human health," says Peter O'Toole of the Bromine Science and Environmental Forum, which represents makers of flame retardants.
Yet Arnold Schecter and his colleagues at the University of Texas recently found this PBDE in breast milk and in foods from supermarkets. "It appears to have been a mistake to think that deca couldn't get into the body," he says. Swedish researchers reported in August that deca, too, can affect brain development in mice. And new studies show that deca can break down in the environment to form penta and octa, as well as other toxic byproducts.
Last month, Washington State lawmakers decided to err on the side of safety and approved the first steps to phase out all three PBDEs. Maine followed suit this month, and California will decide this spring whether to add deca to its ban. Europe may extend its general ban on penta and octa, which will begin this summer, to include all products containing deca.
Still, it's unclear how effective these steps will be in bringing down exposure. Optimists point to Sweden, where PBDE levels in breast milk have already begun to decline. But in the United States and Canada, says Diamond, "there could be a huge lag time for concentrations to come down because of the replacement time for all our gizmos." And PBDEs could still find their way onto the market in imported products.
Industry is at work on substitutes, but the troubled history of chemical flame retardants has convinced some critics that it's time to try making products safe without such additives. One is Clark Williams-Derry, research director for Northwest Environment Watch, the Seattle-based group that tested Laura Gerber. He points to a growing list of companies--Ikea, Motorola, Ericsson, Intel--that have redesigned their products, often using less flammable materials, to eliminate the need to add PBDEs. Says Williams-Derry, "I think we're underestimating our ability to solve this problem through ingenuity."
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