That "great harm" showed up in an alarming number of studies. "The most research has been done on pentabromenated diphenyl ethers (or pentaBDE)," says Blum. But other questionable chemicals include polybrominated diphenyl ethers (PBDEs), "Firemaster 500" (a mixture of flame retardants), tris(2-chloro-iso-propyl) phosphate (TCIPP), tris(1,3-dichloro-2-propyl) phosphate (TDCPP), triphenyl phosphate (TPP), polybrominated biphenyls (PBB), and tetrabromobisphenol A (TBBPA) and tetrachlorobisphenol A (TCBPA).
Blum points out that pregnant women and young children are at the greatest risk. "The developing brain and reproductive organs are vulnerable to endocrine-disrupting chemicals, like these," she explains.
Here are 10 ways scientists say flame retardants are affecting our bodies:
Flame retardants have several ties to cancer. For instance, female firefighters in California between the ages of 40 and 50 face a much higher risk of breast cancer compared to the the national average for that age group. And a previous formulation, tris(2,3,-dibromopropyl) phosphate, was banned from children's clothing in the late 1970s after animal studies showed it caused cancer.
#2. Asthma and Allergies
Dust is a common trigger for those with allergies, but flame retardants could be making the situation worse. Japanese researchers found that TPP found in dust was significantly associated with asthma and allergy symptoms like congestion or runny noses. Also, TCIPP and TDCPP were associated with eczema.
Cat lovers, pay attention. Hyperthyroidism affects more than 10 percent of older cats, leading to weight loss, hyperactivity, aggression, and vomiting, and Swedish researchers have linked this condition to flame retardants. Comparing 37 hyperthyroid cats with 23 healthy cats, the researchers found that those with hyperthyroidism had elevated levels of PBDEs. The researchers point out that cats' grooming methods may leave them especially susceptible to exposure, since they lick the dust off of their fur.
Human thyroids might not be totally safe either: Polish researchers found that exposure to flame retardants is associated with thyroid disruption in humans, too.
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#4. Conception Issues
Couples trying to have a baby should pay attention to flame retardants. Collecting blood samples from 343 pregnant women, research published in Environmental Health Perspectives found that women with higher PBDE concentrations took longer to conceive. Every tenfold increase in PBDE concentration was associated with a 30 percent increase in time-to-pregnancy (the span from when a couple start trying to the time they conceive).
#5. Decreased Semen Quality
Women aren't the only ones taking a hormonal hit from flame retardants. Research from the University of Michigan found that increases in TPP exposure were associated with a 19 percent decrease in sperm concentration.
#6. Early Puberty
Young girls are hitting puberty earlier than ever. While it's not possible to ethically test these chemicals on humans, accidents do happen and can give us a good idea of the possible effects, according to Louise Greenspan, MD, and Julianna Deardorff, PhD, authors of The New Puberty. They point to an incident in 1973 when Michigan cows were unintentionally fed grain treated with PBB. Researchers following pregnant women who ate meat or drank milk from these cows and found that daughters born to these women started menstruating a year earlier than average.
These findings have been echoed in lab tests on animals. Research published in the Journal of Biochemical and Molecular Toxicology found that pregnant rats exposed to Firemaster 500 had pups that experienced early onset of puberty, extreme weight gain, and heart problems. Female pups whose moms were exposed to Firemaster 500 hit puberty four days sooner (at 29 days) than those who weren't exposed to flame retardants (at 33 days). Also, pups in the flame retardant–exposure group were 30 to 60 percent heavier than control group pups, and the males experienced thickening of the left heart ventricle.
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Your TV might be making you fat, but not for the reason you think, according to research published in Toxicological Sciences. The researchers exposed zebrafish larvae to TBBPA and TCBPA, compounds used to prevent electronics from overheating. Exposure to these compounds not only led to lipid accumulation in the larvae, but it also induced weight gain in juvenile fish a month after exposure. Additionally, because zebrafish are transparent, the researchers could see where the fat accumulated: the liver, the heart, the head, and the blood vessels.
"Given the growing obesity epidemic and the serious health conditions it often leads to, our research shows that it's important to study if chemicals are obesogens," said Maria Bondesson, a research assistant professor of biology and biochemistry with the University of Huston's Center for Nuclear Receptors and Cell Signaling. "Our goal is to find the worst ones and then replace them with safer alternatives."
#8. Liver Problems
In addition to obesity, exposure to flame retardants may lead to liver problems. Exposing rats to PBDEs in tests not only led to metabolic obesity, but also to enlarged livers. "Despite the plethora of resources devoted to understanding the roles of diet and exercise in the obesity epidemic, this epidemic continues to escalate, suggesting that other environmental factors may be involved," says Gale Carey, PhD, professor of nutrition at the University of New Hampshire and the lead researcher.
"At the biochemical level, there is a growing body of experimental evidence suggesting certain environmental chemicals, or 'obesogens,' could disrupt the body's metabolism and contribute to the obesity epidemic," says Carey.
Additionally, she found that fat cells became more sensitive to epinephrine and less sensitive to insulin. This meant that, even if the rats didn't gain weight, their bodies were still behaving as if they were obese. One possible explanation for this outcome is that PBDEs seem to suppress a key enzyme in the liver that is responsible for sugar and fat metabolism.
#9. Preterm Birth and Low Birth Weight
Preterm birth is the second leading cause of death in children under age 5, and doctors are rarely certain what causes preterm birth. But research published in the Journal of Reproductive Immunology found that flame retardants may be contributing to this issue, as women with higher concentrations of PBDEs seem to be more likely to have preterm births than women with lower concentrations.
Plus, children born to mothers with higher exposure to PBDEs had lower birth weights, according to research from the University of California–Berkeley.
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#10. Child Development: Lower IQ, Hyperactivity, and Motor Skills
Prenatal and early exposure to flame retardants may have serious impacts on cognitive development in children.
Research published in Environmental Health Perspectives linked higher exposure to lower IQ and hyperactivity in 5-year-old children. The researchers found that a tenfold increase in PBDEs concentrations during early pregnancy was associated with a 4.5-point decrease in IQ scores and 3.3-point increase in hyperactivity scores. The researchers say that this is comparable with the effects of exposure to lead.
Similar patterns continue as children get older. PBDE concentrations at age 7 were associated with attention problems and decreased processing speed, perceptual reasoning, verbal comprehensions, and IQ scores, according to University of California–Berkley and Centers for Disease Control and Prevention researchers.
Flame retardants on their own are bad enough. When combined with other endocrine disruptors, such as phthalates, their harmful effects may be magnified, suggest Canadian researchers. When rat pups were exposed to a combination of phthalates and flame retardants, they demonstrated behavior similar to that of autistic humans. While this finding is certainly concerning, a firm link has yet to be established between human austism and flame retardants (but there is evidence that other types of everyday toxin exposures, like air pollution and PCBs, may be linked to autism).
Make your home a safer place today with this guide for finding flame retardant–free furniture.