News Coverage
Flame Retardants Feel the Heat
Published October 19, 2003
The breast milk produced by American women is contaminated again, this time by brominated flame retardants. Long popular with manufacturers, safety officials, and even the general public, these materials have been coming under increasing fire lately from health and environmental experts. Igniting the debate is a single incendiary question: does the usefulness of such chemicals outweigh the mounting evidence that they are fast accumulating in both the environment and human beings to hazardous effect, and now appearing so close to home?
Flame retardants made a brief splash in the news last month with the release of a study conducted by the Environmental Working Group, which found that the breast milk produced by American women is contaminated with a class of flame retarding compounds called polybrominated diphenyl ethers (PBDEs). Researchers tested the breast milk of 20 first time mothers in 17 cities across 14 states and found that the average amount of the chemicals present in the samples was now at levels that previous studies have associated with toxic effects. Milk from several of the women was found to contain the highest levels of these materials ever detected in human beings.
Levels of PBDEs in the tested milk ranged from 9.5 to 1,078 parts per billion (ppb), with an average level of 159 ppb, and a median value of 58 ppb. Six of 20 participants had PBDE levels above 100 ppb, with two participants exceeding 700 ppb. The highest PBDE level previously reported in the United States was 580 ppb. In contrast, previous studies have found that negative health effects can be triggered by levels as low as 4 ppb.
While the survey sample size of just 20 may seem too small to justify widespread alarm, the results underscored those of a number of other recent studies, all of which have found that PBDE levels in residents of North America are skyrocketing. One study, for example, found that over the past 30 years contamination by brominated flame retardants in breast fat samples of California women has risen dramatically. Samples from the 1960s had no PBDE contamination. Levels measured in samples obtained in the 1990s, however, showed levels 3 to 10 times higher than measurements from Europe taken during the same period. Similarly, researchers in Indiana found that the amounts of brominated flame retardants in maternal and fetal serum in Indiana far exceeded the levels that moved Sweden to ban PBDEs. And in the remote arctic, biologists who've studied ringed seal blubber for the last 20 years have found that levels of PBDEs are increasing exponentially and doubling every four to five years.
PBDEs make excellent flame retardants because they break down when exposed to the high temperatures found in fires. When this breakdown occurs, bromine atoms are released, and bromine is extremely effective at slowing and even stopping the fundamental chemical processes responsible for oxygen-dependent fire. In essence, PBDEs act as built-in automatic fire extinguishers.
PBDEs moved into the marketplace in the late 1970s when a related class of brominated fire retardants called polybrominated biphenyls (or PBBs if you can keep all these acronyms straight!) were banned following a contaminated cattle feed scare. Since that time, their use has been rising consistently. Today, approximately 50,000 metric tons of these materials are produced around the world each year, and 40% of this global total is consumed in North America. PBDEs are primarily used in plastics and foams. As the polymers that make up these materials are being combined, PBDEs are added to the mix. The resulting fire-resistant materials find their way into such wide variety of products that it's a challenge even to list all the categories of goods that contain them. PDBEs are found in computers and peripherals, circuit boards, televisions and other home electronics, coffee makers and other consumer devices, household wiring, smoke detectors, carpets, car seating, polyurethane foams like those found in furniture and mattresses, and imitation wood products just to name a few.
Unfortunately, PBDEs do not chemically bind to the plastics and foams they're used in. Instead, like nuts in a cookie, they remain loose in the final product, completely unattached to or absorbed by anything on a molecular level. These "free floating" PBDEs are able to easily leach out of any materials that contain them. As soon as they do, they make their way to the environment where they've been found in ever increasing amounts in everything from fatty foods to household dust.
This growing contamination is of grave concern because PBDEs are chemically related to dioxins and PCBs, and although they are not yet officially classified as persistent organic pollutants, they exhibit all the trademarks of those fellow toxins: they are extremely resistant to biodegradation and are able to persist in the environment for very long periods of time, they are highly efficient travelers, and they tend to accumulate in animal fatty tissues and move up the food chain. The most worrisome aspect of this pollution is the ability of minute amounts of PBDEs to disrupt the body's thyroid system by depressing levels of key thyroidal hormones. This depression can have serious health effects for adults including fatigue, depression, anxiety, unexplained weight gain, hair loss and low libido. More troubling still, children born to women experiencing such reduced hormonal levels are more likely to have low IQs. Studies have also linked elevated levels of PBDEs to permanent learning and memory impairment, behavioral changes, hearing deficits, delayed puberty onset, decreased sperm count, and developmental disorders.
Fortunately, there are safer alternatives to PBDEs and many manufacturers are now adopting them, a move that tends to undercut industry arguments that a ban on these compounds would lead to increased fire deaths and injuries. In addition to safer substitutes that include compounds based on organic phosphorous, nitrogen, and inorganic flame retardants, companies are finding that they can design more fire-resistant products simply by keeping flammable parts separated from those parts that create heat and by using materials that are naturally fire resistant in the first place. With these replacement technologies in mind, recent laws have been passed in the European Union and California that will phase out PBDEs in coming years. During California's phase-out period, legislation will require manufacturers to place prominent PBDE warning labels on products that contain these chemicals. In many cases, these labels will presumably appear nationally as companies forgo separate state-by-state labeling in favor of a cheaper one-size-fits-all approach. However, companies will not be legally required to alert consumers in other states to the presence of PBDEs in their products. In the possible absence of such warning labels, concerned shoppers are advised to be especially leery of electronic devices and products like furniture that contain foams, the two main domestic sources of PBDE.
There are also steps you can take to protect yourself and your family from PBDEs that may already be present in your home: