Researchers Link Flame Retardants to Hazards

Flame retardants, already linked to effects on the brain, can also alter sex hormones, reducing male fertility and disrupting ovary development, according to scientific studies to be released this week.

Environmental scientists gathering in Boston for an international conference are revealing the results of about 100 new studies showing that the contaminants, which accumulate in breast milk, have spread worldwide and are a greater threat to children and fetuses than earlier research indicated.

Although California has a new law that will ban two types of PBDEs, or polybrominated diphenyl ethers, in 2008, experts warn that the chemicals are expected to keep growing in the U.S. environment and human bodies for years to come. Only California and the European Union have restricted their use.

Also, for the first time, scientists are reporting evidence that another flame retardant -- not subject to any regulation -- poses similar hazards to people and wildlife. The retardant, deca BDE, is used in large volumes in TV sets and computers.

A variety of new studies shows that deca BDE is also accumulating in breast milk and is increasing in the environment, even in remote Arctic lakes. About 100 million pounds of the compound are applied each year to electronics equipment. Because it is not subject to restrictions anywhere in the world, more of it is in use than any other flame retardant.

About 1,000 scientists -- mostly from North America, Europe and Japan -- are gathered at the Dioxin 2003 conference, which is designed to share research on contaminants that persist in the environment and accumulate in human bodies and in wildlife.

Many scientists warn that the chemicals pose a toxic threat that is unprecedented since DDT and PCBs were outlawed in the U.S. in the 1970s. Experts are especially concerned about high exposures in the United States, where the flame retardants are most heavily used.

“These chemicals have been shown to be taken up by the body. They hang around a long time and they accumulate. Even when we stop using them, we will have a legacy that will take years to go away. Decades, probably,” said Linda Birnbaum, the U.S. Environmental Protection Agency’s director of experimental toxicology. The EPA says it is evaluating the risks of the compounds but has no plans to regulate them.

Chemical industry representatives say that the flame retardants are credited with saving thousands of lives worldwide because they have been proved to slow the spread of flames in furniture and electronics. Chemical companies support the California ban on penta and octa PBDEs, used mostly in furniture, but say the restriction of the deca compound used in electronics is unwarranted.

Peter O’Toole, a spokesman for the Bromine Scientific and Environmental Forum -- an industry group representing companies that manufacture PBDEs -- said the “weight of the evidence ... clearly supports the safety” of deca and that several U.S. agencies previously have said it poses no significant risk.

Many scientists gathered at the conference are calling for a more detailed investigation into the amounts and sources of flame retardants in Americans and their food -- particularly fish, meat and dairy products -- and for research that looks for effects in human infants as well as adults. U.S. research has been limited compared to work done in Europe and Canada.

One new study of women in Texas concludes that U.S. women contain “extremely elevated” levels of PBDEs, which “raises concern for potential toxicity to nursing infants,” according to the research led by the University of Texas Health Science Center.

Environmental concentrations are doubling on average every four years in the United States and Canada. Some women are approaching levels that have harmed newborn animals’ developing brains in laboratory tests, scientists say.

Previously, scientists had reported that when small doses of PBDEs used in upholstered furniture and bedding were fed to newborn rodents, it disrupted their thyroid hormones, which guide how the brain develops. That raises concerns that the PBDEs could be causing subtle changes in the intelligence, memory and hearing of human babies, because the hormones control their brain development too.

At this week’s conference, German scientists are reporting that even smaller doses fed to newborn lab animals alter their reproductive development as well, apparently by interfering with estrogen hormones. Studies by Berlin’s Freie Universitat show that the flame retardants are toxic to the female rodents’ ovaries and reduce the males’ reproductive performance, Birnbaum said.

Stockholm University environmental chemist Aake Bergman, who is chairing a session on flame retardants at the Boston conference, said the German studies “indicate a hitherto unknown effect.”

In the 1990s, research by Bergman and other Swedish scientists prompted European industries to voluntarily phase out the two types of PBDEs, and, as a result, levels in breast milk there are declining.

In the United States, however, studies of several hundred people show that women in Indianapolis, Texas and the San Francisco Bay Area have 10 to 100 times more PBDEs in their breast milk and blood than European women. No one knows how the contaminants are getting into human bodies or why some U.S. women are more highly exposed than others living in the same cities.

PBDEs gradually accumulate in human fat and, in pregnant women, pass into the womb and enter the fetus. Babies are highly exposed before birth, and then get an added dose from breast milk. Nonetheless, doctors say women should continue to breast-feed their infants because of the known benefits.

New studies conducted in Europe and Canada report that the compounds are in indoor dust and rural septic tanks. That could mean the source of contamination in people’s bodies is furniture or electronics equipment in their houses or offices.

“My theory is that the exposure is coming through ordinary homes,” Bergman said.

The research implicating deca BDE is stirring the most objections from the chemical industry, which has said that the chemical is benign. Industry groups long have said that it does not accumulate in the environment or human bodies and that there are no proven health risks.

Derek Muir, a research scientist at Canada’s National Water Research Institute, has found the deca compound in the sediments of remote lakes in the Canadian Arctic. Muir said although the common wisdom is that the chemical is not mobile, it apparently is clinging to atmospheric particles and migrating long distances.

Also, for the first time, low levels of deca have been found in women’s breast milk, although it was found in only six of 23 women tested at a Dallas clinic, according to the Texas study, led by Arnold Schecter. O’Toole of the chemical industry group says that fact is reassuring, because it shows most people are unexposed.

But Bergman said it shows that “deca is more of a problem than perhaps realized, and we do have a number of arguments now [to ban it]. We know it is accumulating in birds of prey, and seeing it in mother’s milk is a bad observation.”

Scientists at Sweden’s Uppsala University report that deca reduces the learning ability of rodents exposed as newborns, similar to the PBDEs subject to the California ban.

One of the most intriguing new studies is one by the University of Maryland that shows that when deca is consumed by fish, it transforms itself into the types of PBDEs that are known to be hazardous.

Bergman said the finding is important because it shows that “deca is an environmentally unfriendly compound.”

The European Union is expected to decide this year whether to restrict deca, but there are no such efforts in California or anywhere else in the U.S.