Despite bans, toxic flame retardants continue to show up in pregnant women's blood

February 6, 2018 by Mitzi Baker, University of California, San Francisco
Despite bans, toxic flame retardants continue to show up in pregnant women’s blood
Flame-retardant chemicals – added to upholstered furniture, carpet padding, insulation and many electronics beginning in the mid-1970s – continue to show up in pregnant women despite bans. Credit: University of California, San Francisco

Adding another chapter to the unfolding story of flame-retardant chemicals and their lasting legacy on the environment and human health, a UC San Francisco research team has found that while banning these chemicals initially led to a reduction in exposure, a disturbing trend is emerging of exposure leveling off or even rising again.

Tracey Woodruff, Ph.D., MPH, who directs the UCSF Program on Reproductive Health and the Environment, has been collaborating with clinicians at Zuckerberg San Francisco General Hospital (ZSFG) since 2008 to follow pregnant women and measure blood levels of polybrominated diphenyl ethers (PBDEs). These flame retardant chemicals were added to upholstered furniture, carpet padding, insulation and many electronics beginning in the mid-1970s to reduce ignition and spread of fires.

In 2003, California became the first state to ban these chemicals, although one type of PBDE was in use until 2013. In a previous study, Woodruff found the highest levels of PBDEs ever reported among pregnant women worldwide. In another study she found that once California outlawed the chemicals, there was a corresponding drop in blood levels of pregnant patients at ZSFG.

Her team, which includes researchers from the California Department of Toxic Substances Control and George Washington University, found that PBDE levels in pregnant women did not continue to decrease following the initial drop subsequent to the phase out. The study will be reported in the March 2018 issue of Chemosphere.

"We saw an initial benefit from the regulation but that that benefit is disappearing," said Woodruff, professor in the Department of Obstetrics, Gynecology, and Reproductive Sciences and a member of the Philip R. Lee Institute for Health Policy Studies.

Rather than being chemically bonded to products, these are mixed in, so they readily leach out into the air and migrate into the environment. Studies have found dangerously high levels in fish, dairy and meat products and house dust – and also in people's blood, women's breast milk and umbilical cord blood of newborns.

The U.S. Environmental Protection Agency documents that these chemicals may cause toxicity to the liver, thyroid and nervous system – effects that may be magnified in babies or if a fetus is exposed to them in utero. Woodruff recently published evidence that higher levels of exposure to flame retardants in damages their children's intelligence.

"What was really interesting was that the levels of these chemicals dropped quickly following phase-outs and bans," she said. "It is a reminder that policies and regulations can influence our exposures and our health."

However, she cautioned, despite the positive changes seen with the bans on PBDE flame retardants, her new study is a reminder that there is still plenty about these chemicals to warrant continued concern.

"Putting these types of chemicals out into the environment are a lot like opening Pandora's box: They are really hard to get back," said Woodruff. "The plateau effect we are seeing also reminds us to consider the effects of other chemicals in the environment."

The data make sense, she said, because nearly everyone is continuing to be exposed to the chemicals even long after the bans, both from decades-long persistence in the environment and the food chain, and from old furnishings and electronics that continue to release them.

Although California has changed its regulatory standards so that PBDEs aren't necessary in upholstered furniture any longer, the chemicals are still in use for other applications. Additionally, substituted flame retardant chemicals may also have harmful effects.

In support of minimizing exposure to PBDEs, she lauded the recently passed San Francisco law that bans the sale of all flame retardant chemicals in upholstered furniture in the city, including online. She noted that combining the right cover fabrics and barrier materials can provide fire safety protections. "Applying technology solutions will create a win-win situation for the consumer," she said.

Woodruff, who used to work for EPA as a senior scientist and policy adviser, continues to evaluate exposure long-lasting in support of policy change. She has expanded her inquiry into some of the flame retardants that have replaced the banned ones, and posts updates about chemicals persisting in the environment and food chain in a blog for the UCSF Program on Reproductive Health and the Environment.

"The bottom line is that it is great to ban these toxic chemicals – but these kinds of persistent, toxic chemicals shouldn't be let out in the first place," she said. "We have to ask that our government doesn't keep repeating this mistake of letting these chemicals into the marketplace and harming our health. It's a legacy that is difficult to overcome."

Explore further: Flame retardant exposure found to lower IQ in children

More information: Emily Parry et al. Polybrominated diphenyl ethers (PBDEs) and hydroxylated PBDE metabolites (OH-PBDEs): A six-year temporal trend in Northern California pregnant women, Chemosphere (2017). DOI: 10.1016/j.chemosphere.2017.12.065

Related Stories

Flame retardant exposure found to lower IQ in children

August 4, 2017
A hazardous class of flame retardant chemicals commonly found in furniture and household products damages children's intelligence, resulting in loss of IQ points, according to a new study by UC San Francisco researchers.

High levels of potentially toxic flame retardants in California pregnant women

August 10, 2011
A new study finds that pregnant women in Northern California have the highest PBDE flame retardant exposures reported to date among pregnant women worldwide. It also describes some of the first evidence from humans that certain ...

Flame retardants linked to preterm birth

January 28, 2015
Researchers at The University of Texas Medical Branch have determined that maternal exposure to high levels of flame-retardants may be a contributing factor in preterm births.

First US study to measure exposure to 59 toxic chemicals in pregnant women and their newborns

November 3, 2016
Low income and Latina pregnant women who seek care at Zuckerberg San Francisco General Hospital and Trauma Center (ZSFG) have widespread exposure to environmental pollutants, many of which show up in higher levels in newborns ...

Exposure to common flame retardant chemicals may increase thyroid problems in women

May 23, 2016
Women with elevated levels of common types of flame retardant chemicals in their blood may be at a higher risk for thyroid disease—and the risk may be significantly higher among post-menopausal women, according to a new ...

Minimizing exposure to harmful flame retardant chemicals in waste foams and plastics

January 29, 2018
Continued research and new policies and practices to ensure proper use and disposal of foam and plastic products that contain potentially harmful flame retardant chemicals are needed to minimize health risks from environmental ...

Recommended for you

How to survive on 'Game of Thrones': Switch allegiances

December 9, 2018
Characters in the Game of Thrones TV series are more likely to die if they do not switch allegiance, and are male, according to an article published in the open access journal Injury Epidemiology.

Expert calls for strong, sustainable action to make world roadways safer

December 7, 2018
According to the latest World Health Organization (WHO) report on road safety, more than 1.3 million people die on the world's roadways each year—and millions more are injured or disabled. Yet despite the huge cost to families ...

Hazelnuts improve older adults' micronutrient levels

December 6, 2018
Older adults who added hazelnuts to their diet for a few months significantly improved their levels of two key micronutrients, new research at Oregon State University indicates.

Regular bedtimes and sufficient sleep for children may lead to healthier teens

December 6, 2018
Having a regular, age-appropriate bedtime and getting sufficient sleep from early childhood may be important for healthy body weight in adolescence, according to researchers at Penn State.

Stress from using electronic health records is linked to physician burnout

December 5, 2018
While electronic health records (EHRs) improve communication and access to patient data, researchers found that stress from using EHRs is associated with burnout, particularly for primary care doctors such as pediatricians, ...

Chemicals in personal care and household products linked to earlier puberty in girls

December 4, 2018
Chemicals that are widely used in personal care and household products are linked to girls entering puberty at earlier ages, according to findings from a long-running study of mothers and children published today.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.