Days may be numbered for two fire retardants - Flaming Out? - products made from polybrominated diphenyl ethers

Science News, Nov 1, 2003 by J. Raloff

This August, at a meeting of Environmental Protection Agency scientists who are studying emerging pollutants, one family of chemicals unexpectedly stole the show: brominated flame retardants. Recently slated for bans in Europe and California, two classes of these compounds--mixes of polybrominated diphenyl ethers (PBDEs)--have had a low profile within the agency. But rank-and-file chemists and toxicologists raised what became the meeting's central question: What would it take for EPA to consider nationwide bans?

As it turns out, the U.S. manufacturer of both flame retardants has taken things into its own hands.

On Oct. 24, EPA issued a terse statement: "Great Lakes Chemical Corp. has initiated discussions with EPA regarding a possible voluntary phase-out of penta- and octa-PBDEs along with a full evaluation of a viable alternative." This week, Great Lakes spokesperson Wendy Chance acknowledged that her Indianapolis-based company had prompted the discussions and would "work aggressively with [EPA] on the issue."

PBDEs are molecules that can hold up to 10 bromine atoms in 209 different configurations, or congeners. Commercial mixtures of PBDEs used as flame retardants are typically dominated by congeners with a given number of bromines. The penta mix, with mostly 5-bromine PBDEs, is used to make foams, paints, and wire coatings resistant to burning. The octa formulation, with mostly 8-bromine PBDEs, is used primarily to flameproof plastic casings on office equipment.

PBDEs leach from treated products and have become ubiquitous, including in the bodies of people (SN: 10/13/01, p. 238). More troubling, new animal data indicate that penta and octa mixes can poison reproductive, nervous, and hormonal systems (SN: 10/25/03, p. 266). Manufacturers of the flame retardants estimate that their products save at least 300 U.S. lives annually.

A third PBDE formulation, based on the fully brominated, or deca, congener known as BDE-209 isn't slated for a phaseout anywhere. It "represents the major product in all markets, accounting for around 80 percent of the total PBDE production worldwide," note EPA scientists Linda S. Birnbaum and Daniele F. Staskal in a review paper in an upcoming Environmental Health Perspectives. What's more, they note, PBDEs in the commercial mixes, including the deca form, can shed bromines and thus convert into other PBDEs.

Chemist Heather Stapleton of the University of Maryland Center for Environmental Science in Solomons and her colleagues found that BDE-209 debrominates rapidly in fish. For 2 months, the researchers fed carp food laced with BDE-209. Over the succeeding 40 days, seven PBDEs began appearing in the animals' tissues, all with between 5 and 8 bromines.

Ake Bergman of Stockholm University notes that he and others have demonstrated that solar ultraviolet light can debrominate BDE-209 into smaller PBDEs. If these molecules warrant a phaseout and the deca form can transform into them, then BDE-209 also deserves a phaseout, he says.