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BackPage Primer from Environmental Building News

June 1, 2009

Brominated Flame Retardants

Keeping things from catching fire and burning up is a good idea, especially when those things are parts of our buildings or the furnishings we put in our buildings. Flame retardants—chemicals added to products either during manufacture or afterwards—are one of the ways we make products more resistant to igniting or burning (see EBN June 2004).

The problem is that some flame retardants, particularly brominated compounds, aren’t good for us or for the environment. Back in the early 1970s in Michigan, a polybrominated biphenyl (PBB) flame retardant was accidentally mixed with livestock feed and hundreds of thousands of cows and other livestock had to be destroyed, leading to the banning of PBBs. So manufacturers switched to a chemically very similar class of compounds, polybrominated diphenyl ethers (PBDEs), that weren’t known to be toxic.

It surprises a lot of people to learn that, except for pharmaceuticals and pesticides, chemicals in the U.S. do not have to be tested for health and environmental safety before they are introduced—and manufacturers aren’t even required to divulge what’s in products when the quantities are small. Since the 1970s, huge quantities of PBDEs and other brominated flame retardants have been used in everything from computer cases to foam insulation and upholstery stuffing. Here’s a quick summary of brominated flame retardants in use today:

decaBDE (83% bromine)—Often referred to as “deca” and commonly used for hard plastics and fabric backing, especially since octaBDE was phased out of production. There is considerable evidence of bioaccumulation as well as breakdown into more dangerous forms of BDE; potential impacts on behavior, learning, and memory, and some evidence of liver cancer.

TBBPA (Tetrabromobisphenyl A; 50% bromine)—Widely used for epoxy resins and hard plastics. Little is known about health and environmental effects, but the compound is widely found in the environment.

HBCD (Hexabromocyclododecane; 75% bromine)—Used in nearly all polystyrene foam insulation as well as in upholstery fabric backing and in some hard plastics. It is widely found in household dust and has been shown to bioaccumulate; there is evidence of effects on behavior, learning, and memory after neonatal exposure.

DBDPE (Decabromodiphenyl ethane, 82% bromine)—Made in China and used in hard plastics, cables, textiles, and certain foams. Little is known about environmental and health problems.

Alternatives to brominated flame retardants include certain compounds containing chlorine (chemically, a halogen that is similar to bromine), phosphate, phosphorus, ammonium, aluminum trihydroxide, borax (sodium borate), antimony, and melamine cyanurate. Of these, chlorinated flame retardants, such as TDCP (chlorinated Tris), are persistent in the environment but may be less likely to bioaccumulate than brominated compounds. Some chemists believe that chlorinated flame retardants may be just as toxic as their brominated cousins. The other (non-halogenated) flame retardants are generally considered much safer.

In addition to chemical flame retardants, manufacturers are increasingly turning to physical fire barriers—for example, special fire-blocking layers in mattresses, reducing the use of flame retardants in these products. Eliminating the need for chemical flame retardants or using inherently fire-resistant materials is the greenest approach.

DISCUSSIONS

Reader-contributed comments related to EBN: 18:6 - Brominated Flame Retardants. Comments are listed with newest at the top.

Fire retardants for solid wood Posted by Alex Wilson on Jun 4, 2009, 04:51 PM
Most of the spray-applied fire retardants for wood are aqueous solutions of phosphates, sodium or potassium silicates, or borates--or some combination of these. Most are transparent and soak into the wood. It's often quite difficult to figure out exactly what these compounds are, because the MSD sheets often say only "proprietary ingredients" without identifying them. Compared to the brominated or chlorinated flame retardants used in most plastics, these compounds used on wood are considered much safer. -Alex Wilson

Fire retardant coatings for solid wood Posted by Erika Hanson on Jun 4, 2009, 03:09 PM
When a fire retardant coating is required by code for an interior wood surface, are there any "greener" options available? Most of the posts about fire retardant chemicals that I've seen on this site relate to plastic foams and housings rather than wood.

Healthy Building Network Posted by Dave Intner on Jun 3, 2009, 04:16 PM
One of the best resources for additional information on this topic is the Healthy Building Network.

http://www.healthybuilding.net/

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