U.S. demand for flame retardants is increasing 4.6% a year to a projected 938 million pounds by 2016, according to market research released in October.

One of the best-selling flame retardants, produced in the range of 10-50 million pounds a year, is chlorinated Tris—a chemical that Blum and fellow Berkeley researcher Bruce Ames flagged as a carcinogen nearly 35 years ago. It’s the most commonly used flame retardant in furniture. As a resident of California, your couch probably has a little tag saying it complies with TB117—which means it contains about a pound of chlorinated Tris.

In a new study released this week, Blum and her colleagues found flame retardants in 85% of 102 couches they tested. The team analyzed couch samples purchased before and after California phased out the flame retardant formula known as Penta to find out which alternatives manufacturers turned to. Of samples bought before 2005, nearly 40% contained Penta and a quarter had chlorinated Tris. After the Penta phaseout, more than half the samples contained chlorinated Tris, and close to 20% had a little-studied replacement called Firemaster 550.

Recent research links Penta to decreased fertility, lower birth weight and cognitive deficits in children. Chlorinated Tris is a suspected human carcinogen and researchers haven’t had time to study the health effects of Firemaster 550. Since most people tend to keep big ticket items like couches for 20 years or more, there’s no telling how many home have Penta-treated furniture. Based on Blum’s recent research, most of us probably have Tris-treated couches.

But why do our couches have a pound of cancer-causing chemicals that build up in our dust—and our bodies?

As you may have heard by now, in 1975 California implemented TB117, which requires foam inside your couch to resist a very small flame for 12 seconds. But the first thing to burn when a cigarette or candle drops on your couch isn’t the foam, it's the fabric. As fabric burns, it generates a large flame, which in turn ignites the foam, which burns within a few seconds. When fire burns without flame retardants, it releases carbon dioxide and water. In the presence of flame retardants, fires release far more soot, smoke and carbon monoxide—which is what kills you in a fire.

TB117 doesn’t increase fire safety, Blum says. It just increases our exposure to toxic chemicals. And flame retardants are showing up in products that aren’t even listed in the standard. Sleep mats aren’t subject to the standard, yet one study found that all the sleep mats in 20 nursery schools in the East Bay contained flame retardants. Most of the foam products in America, including mattress pads and pillows, use flame retardants to comply with TB117, even though it’s not required.

Blum believes that Gov. Jerry Brown, who directed state agencies to revise the standard in June, is determined to achieve fire safety without toxic chemicals.

And with a safer furniture standard within reach, she’s set her sights on an even bigger problem: foam plastic insulation in buildings. The Uniform Building Code, which regulates foam plastic insulation in walls, requires a 15-minute thermal barrier (typically gypsum wallboard) to protect them from the heat of a fire.

“By the time you hit the insulation, you’ve had a raging fire in your house for 15 minutes,” Blum says. “Having flame retardants in the insulation just makes the fire more toxic.”

Flame retardants used in building insulation are turning up in the environment, household dust and human body fluids at increasing levels, Blum and her colleagues report in a new study released this week. Studies link the compounds to endocrine disruption, neurological and developmental toxicity and the potential to cause cancer.

Thanks to a recovering housing market, construction is driving most of the growth in the flame retardant market and accounts for the greatest share of sales.

Ironically, many green builders use flame-retardant-treated plastic insulation to boost energy efficiency.

All these flammability standards—which increase our exposure to toxic chemicals without increasing fire safety—went into effect in the 1970s, “perhaps not with malice aforethought,” Blum says. “But now’s the time to do something.”