Flame retardants

Efforts to reduce fire hazards over a half century ago have left an unintended trail of persistent environmental contaminants from flame retardant chemicals known as PBDEs. Bans and substitutes are still evolving.

Room fire simulation shows burned furniture. Photo: Kecko (CC BY 2.0) https://www.flickr.com/photos/kecko/3648477592/
Room fire simulation shows burned furniture. Photo: Kecko (CC BY 2.0) https://www.flickr.com/photos/kecko/3648477592/

Beginning in the 1950s, the fear of fire has kept the door open to the use of chemicals to reduce death and injury from house fires ignited by cigarettes and other heat sources.

In 1973, the state of California took an unprecedented action to reduce fire danger posed by polyurethane foam — a highly flammable material that was becoming widely used in furniture. The California regulation, known as Technical Bulletin 117, required that any foam used in furniture be made to withstand an open flame for at least 12 seconds.

The use of chemical flame retardants soon became a standard practice for furniture manufacturers across the country. Such chemicals were also incorporated into building materials, electronics, automobiles and fabrics.

At least 75 flame retardants were developed using the element bromine. Among them were the polybrominated diphenyl ethers, or PBDEs. It turns out that properties that make for good flame retardants — including chemical stability — also cause them to persist in the environment, breaking down slowly. Many of these compounds are lipophilic, which allows them to build up in the fat tissues of animals. And many have turned out to cause a variety of toxic effects in humans and animals.

What began as a reasonable desire to save lives through chemistry turned out to create unexpected and uncertain health risks for people and animals around the globe.

How are we exposed to flame retardant chemicals? Flame retardants not bound to foam off-gas and settle into dust that can be ingested upon contact. Diagram courtesy: Green Science Policy Institute
How are we exposed to flame retardant chemicals? Flame retardants not bound to foam off-gas and settle into dust that can be ingested upon contact. Diagram courtesy: Green Science Policy Institute http://greensciencepolicy.org/topics/furniture/

In 2014, California amended its flame-resistance standard after experts concluded that flame-resistant fabric surrounding the flammable foam was adequate to prevent ignition. That could be accomplished without chemicals by using less flammable fabrics with tighter weaves. By the time California revised its standard, a dozen states had banned certain flame retardants — with some bans coming after 2004, when manufacturers voluntarily stopped selling two of the more toxic PBDEs.

With bans on PBDEs in many states, manufacturers shifted to other flame retardants in a variety of products, including computers, televisions and electronic devices that can get very hot. Being neither a drug nor a pesticide, newly formulated flame retardant compounds came into use with minimal testing for safety. Now studies are beginning to show toxic effects for some of these substitutes as well.

The state of Washington, which banned most uses of PBDEs in 2008, followed up this year with a ban on five other flame retardants in products used by children. The Legislature also ordered additional scientific review for six other flame retardants.

About the Author: 
Christopher Dunagan is a senior writer at the Puget Sound Institute.