Cause for Alarm Over Chemicals

The chemicals, PBDEs, or polybrominated diphenyl ethers, are used to reduce the spread of fire in an array of plastic and foam products in homes and offices, including upholstered furniture, building materials, televisions, computers and other electronic equipment.

This year, the European Union banned the two PBDE compounds that have been shown to accumulate in human bodies. Some European industries had already begun to phase out the chemicals, and levels in the breast milk of European women have begun to decline.

But in the United States, no action to regulate the flame retardants has been taken, and their use continues to rise. About half of the 135 million pounds of PBDEs used worldwide in 2001 were applied to products in North America.

Scientists who specialize in toxic contaminants say they haven't seen a chemical build up in human bodies and the environment as quickly as that of PBDEs in almost half a century. The flame retardants are as potent and long-lasting as PCBs (polychlorinated biphenyls) and DDT-- chemicals that began to accumulate in the environment in the 1950s and were banned in the 1970s. Even if PBDEs were banned today, they would endure in the environment for decades, scientists say.

A single, small dose of PBDEs fed to newborn laboratory mice and rats disrupts their brain development, altering their learning ability, memory, behavior and hearing, according to three studies, two conducted in Europe and one at the U.S. Environmental Protection Agency. Mice fed less than 1 part per million of PBDEs performed poorly in maze tests and were hyperactive and slower to become habituated to new environments.

"These effects are persistent and worsen with age," said Per Eriksson, a neurotoxicologist at Uppsala University in Sweden who led the rodent studies.

Only a few hundred people in the U.S. have been tested so far. But studies completed in the last few months show that some American women and their babies are carrying levels of PBDEs that are beginning to approximate those that harm newborn rodents.

The brains of newborn mice are altered when their bodies contain concentrations that are 10 to 100 times higher than levels already seen in some people in the United States today.