Tag Archives: flame retardants

Are Flame Retardants Safe? Growing Evidence Says ‘No’.

by Elizabeth Grossman: originally published 29 Sep 2011 in Yale360

Over the past 40 years, a class of chemicals with the tongue-twisting name of halogenated flame retardants has permeated the lives of people throughout the industrialized world. These synthetic chemicals — used in electronics, upholstery, carpets, textiles, insulation, vehicle and airplane parts, children’s clothes and strollers, and many other products — have proven very effective at making petroleum-based materials resist fire.

Yet many of these compounds have also turned out to be environmentally mobile and persistent — turning up in food and household dust — and are now so ubiquitous that levels of the chemicals in the blood of North Americans appear to have been doubling every two to five years for the past several decades.

Acting on growing evidence that these flame retardants can accumulate in people and cause adverse health effects — interfering with hormones, reproductive systems, thyroid and metabolic function, and neurological development in infants and children — the federal government and various states have limited or banned the use of some of these chemicals, as have other countries. Several are restricted by the Stockholm Convention on persistent organic pollutants. Many individual companies have voluntarily discontinued production and use of these compounds. Yet despite these restrictions, evidence has emerged in recent months that efforts to curtail the use of such flame retardants — a $4 billion-a-year industry globally — and to limit their impacts on human health may not be succeeding.
This spring and summer, a test of consumer products, as well as a study in Environmental Science & Technology, showed that use of these chemicals continues to be widespread and that compounds thought to be off the market due to health concerns continue to be used in the U.S., including in children’s products such as crib mattresses, changing table pads, nursing pillows, and car seats. Also this summer, new research provided the first strong evidence that maternal exposure to a widely used type of flame retardant, known as PBDEs (polybrominated diphenyl ethers), can alter thyroid function in pregnant women and children, result in low birth weights, and impair neurological development.

“Of most concern are developmental and reproductive effects and early life exposures — in utero, infantile and for children,” Linda Birnbaum, director of the National Institute of Environmental Health Sciences and the National Toxicology Program, said in an interview.

Read full post here.

ABOUT THE AUTHOR
Elizabeth Grossman is the author of Chasing Molecules: Poisonous Products, Human Health, and the Promise of Green Chemistry, High Tech Trash: Digital Devices, Hidden Toxics, and Human Health, and other books. Her work has appeared in Scientific American, Salon, The Washington Post, The Nation, Mother Jones, Grist, and other publications. In earlier articles for Yale e360, she explored how the Fukushima nuclear plant disaster could affect marine life off the Japanese coast and reported on recent studies suggesting a possible link between prenatal exposure to pesticides and the mental abilities of children.
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The Toxins in Baby Products (and Almost Everywhere Else)

Read original post at The Atlantic (online)

By Elizabeth Grossman

Jun 2 2011, 11:15 AM ET

Carcinogenic flame retardants were supposed to be gone by now, but, like endocrine-disrupting plasticizers, they persist

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A dangerous flame retardant known as “Tris” has reappeared in products designed for babies and young children, among them car seats, changing table pads, portable crib mattresses, high chair seats, and nursing pillows. (Tris, once used in children’s sleepwear, was removed from these products in the 1970s, after it was identified as a carcinogen and a mutagen, a compound that causes genetic mutation.) Also found in these products, according to the same recent study, which appeared in Environmental Science & Technology, is another flame retardant, pentaBDE. This compound was banned in Europe in 2004, when its U.S. manufacturers voluntarily discontinued it after it was found to be environmentally persistent, bioaccumulative, and to adversely affect thyroid function and neurological development.

The study also identified new compounds whose ingredients include some of the older toxic substances—and it found all of these and other flame retardants in 80 percent of the 101 infant and children’s products tested. That these chemicals, associated with adverse health impacts including cancer and endocrine disruption, are so widespread raises serious questions about the U.S. system of chemicals management and how we evaluate product safety.

With the potential health hazards of widely used synthetic chemicals coming under increasing scrutiny, and with a growing call from medical and scientific professionals for policies that protect children from such hazards, the question of what takes the place of a threatening chemical has become increasingly important. It also prompts questions about whether it is better to substitute another chemical for the one posing problems or to redesign a product so it can achieve its desired performance, perhaps without such chemicals.

Together these flame retardants and plasticizers raise profound questions about how we think about designing new materials and the wisdom of regulating chemicals one at a time.

The brominated and chlorinated flame retardants (BFRs and CFRs) found in these children’s products offer one cautionary example. Another group of chemicals known as phthalates, used to increase the flexibility of one of the world’s most widely used plastics, polyvinyl chloride (PVC), offers another. Together, these compounds account for the vast majority of all plastics additives used worldwide.

In the case of the flame retardants used in upholstery foams, carpet backings, textiles, and hard plastic appliances and other products since the 1970s, new compounds introduced to replace the hazardous ones have in fact resembled their predecessors. The result, despite “early warnings and periodic reminders about the problematic properties of these chemicals” is a “continuing pattern of unfortunate substitution,” wrote Linda Birnbaum, director of the National Institute of Environmental Health Sciences and National Toxicology Program, and Ake Bergman, professor of environmental chemistry at Stockholm University, in Environmental Health Perspectives in October. They were introducing a statement of concern about BFRs and CFRs signed by nearly 150 scientists from 22 countries.

While cushions and electronics can function without flame retardants, PVC cannot work without plasticizers. Phthalates—oily, colorless liquids based on benzene chemistry—have been the plasticizers of choice since PVC was commercialized in the early 20th century. Without phthalates, PVC would be brittle and of limited use. In some bendable PVC products, phthalates can make up as much as 40 to 50 percent of the finished plastic—and in 2008, nearly 540 billion pounds of PVC were produced worldwide.

Phthalates are also used in other vinyl-based products, to create thin and flexible films (they’ve been used in nail polish and other cosmetics), as lubricants (hence their use in lotions), as solvents, and to extend the life of fragrances, among many other applications. They are found in everything from food packaging to insect repellant to bath and teething toys. Some phthalates have been shown in animal studies to cause birth defects, and a number of popular phthalates have been identified as endocrine disrupters that interfere with male reproductive development. Concerned, Europe restricted use of about half a dozen phthalates in 2008, and the U.S. restricted them in products intended for use by children under age 12. Similar regulations exist elsewhere, including Canada, Japan, and Taiwan. On May 4, the French National assembly voted to ban phthalates altogether, based on concerns about endocrine disruption.

Like the BFR and CFR flame retardants, phthalates are released from the materials to which they’re added. That phthalates could migrate from PVC has been known since the 1960s, when the Air Force found that this could cause problems on spacecraft and phthalates were detected leeching from plastic tubing used in blood transfusion and dairy equipment. We can take phthalates into our bodies by breathing them, ingesting them, and by absorbing them through our skin. A study published in March of this year found that when people eliminated certain packaged foods from their diets, levels of the corresponding phthalates in their urine dropped by more than 50 percent.

So with growing concerns about phthalates and increasing restrictions on their use, a search is on for alternatives—ideally non-toxic compounds that will not migrate out of the plastics. But PVC itself, even without the phthalates, raises questions about product safety. While it may be possible to find a non-toxic plasticizer, vinyl chloride, the main ingredient of PVC chloride, is a human carcinogen that also causes liver and nerve damage. PVC also poses hazards when burned, as incomplete combustion can result in dioxins, also carcinogenic compounds. In April, the Environmental Protection Agency proposed increasing emissions standards for plants that product PVC, citing inhalation risks to people who live in communities where these manufacturing facilities are located. There are currently 17 such plants in the U.S., mostly in Louisiana and Texas.

Together these flame retardants and plasticizers raise profound questions about how we think about designing new materials and the wisdom—from an environmental health perspective—of regulating chemicals one at a time rather than by examining their characteristics and behavior. They also point to the need to look at a product’s entire lifecycle when considering its health impacts. There are many arguments to be made about the costs and benefits of using these materials, and moving away from such widely and long-used materials presents many challenges. Yet as Paul Anastas and John Warner, often considered to be the founders of green chemistry, point out, there is no reason a molecule must be hazardous to perform a particular task. To solve the kinds of problems posed by materials like PVC, “we need to design into our technologies the consequences to human health and the environment.”

Image: mbaylor/flickr

Simple green synthesis of polyborosiloxanes as environmentally-safe, non-halogenated flame retardant polymers.

Journal Article
Ravi Mosurkal, Romy Kirby, Wayne S. Muller, Jason W. Soares and Jayant Kumar

Green Chem., 2011, Advance Article

DOI: 10.1039/C0GC00376J, Paper


A novel class of boron-containing siloxane copolymers (polyborosiloxanes) was synthesized by simple environmentally friendly methods. A boron containing monomer, specifically phenylboronic acid (PBA), and imide forming monomers, specifically aromatic dianhydrides 4,4′-oxydiphthalicanhydride (Oxy) and 1,1,4,4-tetracarboxylicphenyldianhydride (DAH), were employed to make terpolymers with propylamino-terminated polydimethylsiloxane (A12-PDMS). The terpolymer synthesis was carried out using various PBA : Oxy and PBA : DAH compositions ranging from 0 : 1 to 1 : 0 mole ratios. The thermal and flame retardant properties of the novel polymers were investigated. Intermediate ratios of both PBA : Oxy and PBA : DAH resulted in optimal thermal stability and flame retardancy. These novel terpolymers are promising candidates as environmentally-safe, non-halogenated alternatives to traditional flame retardant polymers.

Graphical abstract: Simple green synthesis of polyborosiloxanes as environmentally-safe, non-halogenated flame retardant polymers

A safer flame retardant protects an everyday plastic.

Xiang, H, C Sun, D Jiang, Q Zhang, C Dong and L Liu. 2010.  Flame retardation and thermal degradation of intumescent flame-retarded polypropylene composites containing spirophosphoryldicyandiamide and ammonium polyphosphate. Journal of Vinyl and Additive Technology 16:161-169.

Synopsis by Evan Beach, Sep 10, 2010

Polypropylene plastic (PP) was less flammable yet remained strong when mixed with two chemicals considered safer than those currently used as flame retardants, report Chinese researchers. The chemical blend achieved the highest flame retardancy rating in standardized tests without significantly impacting the strength of the plastic.

PP, which is coded as number 5 in plastic recycling, is used in numerous consumer products including carpets and thermal underwear.

The new flame retardant is a step forward in finding an alternative to traditional systems that are based on halogen-containing chemicals and antimony trioxide, say the researchers who developed the chemical blend. Alternatives are desired to prevent toxic, corrosive gases from forming during fires. Also, several classes of halogen-based flame retardants – like polybrominated diphenyl ethers – are raising concerns about persistence in the environment, toxicity and accumulation in animals and humans.

One of the additives, ammonium polyphosphate, is well known as a flame retardant, but by itself it cannot protect PP. The scientists invented a second additive –  spirophosphoryldicyandiamide (SPDC) – that created synergy in the polymer blend. In the presence of a flame, the two additives formed a protective char layer that shielded the inside of the plastic from heat and prevented flaming drips. The combination also reduced heat, carbon monoxide gas and smoke.

Cost might limit the practicality of the new system. However, perfomance was adequate when the more expensive SPDC chemical was limited to just 25 percent of the flame retardant combination. The total amount of additives in the experiments was 30 percent of the plastic by weight.

The researchers showed that the new additives are safer compared to halogenated chemicals during fires. But, the overall green benefits of their technology are still not calculated. Further testing of the blends’ leaching, persistence and toxicity is necessary.  Also, several highly toxic starting materials – like dicyandiamide and phosphorus oxychloride – are needed to make SPDC. These would be dangerous to workers and surrounding communities in the event of an accident.