New study finds that banned flame retardants have declined in California pregnant women
Polybrominated diphenyl ethers or PBDEs were banned in California and phased out of national production in 2003-2004. PBDEs are a class of flame retardants that have been shown to damage the brain in utero in animal studies and have been linked to learning difficulties in children in human epidemiologic studies. The chemicals also can disrupt thyroid hormones in adulthood and during development. PBDEs were used in foam furniture starting in the 1970s in order to meet furniture flammability standards. Residents of California historically have the world’s highest non-occupational exposures to several types of PBDEs because of the state’s unique flammability standard for foam furniture.
Our bodies are exposed to PBDEs through numerous venues. The chemicals wear off foam furniture and turn into household dust which can be ingested by adults and children. Our diets are another source- as PBDEs are persistent and accumulate up the food chain- so eating fish, meat and dairy products are another avenue of exposure. Human breast milk has also been found to have significant levels of PBDEs, although breastfeeding is still thought to be the best and healthiest way to feed your baby.
We decided to examine temporal trends of PBDE exposures in pregnant women in California to determine whether their levels of PBDEs would be impacted by chemical regulations. Our study found a dramatic decline in the average blood levels of PBDEs in pregnant women during the study period.
We tested patients at San Francisco General Hospital and Trauma Center which serves a diverse population that may be at higher risk of exposure to flame retardants because they reside in California, they do not have access to higher quality furniture and live in housing that is of poor quality.
Our study compared a group of twenty-five women who came to the hospital from 2008 to 2009 to thirty six women who came between 2011 and 2012. The first group had the highest reported levels of PBDEs of any group of pregnant women tested worldwide. When we tested again, three years later, the second group's overall PBDE levels fell by two-thirds.
Every woman tested in 2008-2009 had all five of the PBDEs measured by the researchers in her blood. But by 2011-2012, only one of the PBDEs was present in every women tested and the overall levels of all five PBDE’s were significantly lower in the second group.
Our study is the first to show a decline in PBDEs in pregnant women since they were phased out of use and regulation. Past research revealed that PBDEs in California house dust have also declined over this time period.
The results of the study highlight how public policy can have an impact on our communities’ lives and health. The dramatic decline in PBDEs levels was the result of the California ban and the national phase-out of these harmful chemicals.
Despite PBDEs being banned in furniture, manufacturers have substituted other chemicals, which may also be harmful. Chlorinated Tris, for example, is a suspected carcinogen listed on California’s Proposition 65 list.
Fortunately, in September 2013 California Governor Jerry Brown announced the reform of TB-117, the flammability standard which required foam in furniture to withstand exposure to an open flame and precipitated flame retardants being added to furniture. The California reform will allow for fire safety without the use of flame retardants. Because California is the only state with this unique standard, the change in TB-117 has national implications.
Going forward, we need to update the Toxic Substance Control Act, the federal law which regulates and manages chemicals in consumer products. Unfortunately, the law does not require that manufactures provide the government with safety data on chemicals prior to them going on the market. It also does not empower the U.S. EPA to move quickly on known hazardous chemicals, including bans or phase-outs if necessary.
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