Ask a public health scientist about couches and cancer, and you’re sure to hear about a State of California law enacted back in 1975. That law, called technical bulletin 117, or “TB117”, required furniture manufacturers to treat their products with flame retardant chemicals, mainly to protect against fires started by neglected cigarettes.

“Most manufacturers didn’t want to have two production lines—one for California and one for the rest of the country—so after the regulation was passed most furniture included flame retardants,” says Heather Stapleton, associate professor and program chair of environmental health at Duke University. “Later on it was found that these flame retardants could migrate out of the products and into people.”

For the past decade, Stapleton has conducted a series of studies identifying the types and concentrations of flame-retardants used in consumer products. She and others say there is ample animal and lab research to suggest these chemicals may promote a number of health concerns, including cancer.

Get our Health Newsletter. Sign up to receive the latest health and science news, plus answers to wellness questions and expert tips. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

“There are concerns about endocrine disruption and neurotoxic effects, especially for pregnant women and children,” says Asa Bradman, associate director of the Center for Environmental Research and Children’s Health at the University of California, Berkeley.

Bradman says these flame-retardants work their way out of your furniture and into the dust that coats your floors and other surfaces. From there, you or your children may be exposed by breathing them in or putting something in your mouth—fingers, a toy—that has been in contact with the chemical-coated dust particles.

Bradman says it’s difficult to pinpoint the precise toxicological and dose-response effects of these chemicals. “Several studies suggest associations between exposure to some flame retardants and poorer neurodevelopment in children,” he says.

But the average American is exposed to hundreds of chemical compounds on a daily basis. There are hormone-disrupting agents in your deodorant and your food and your clothing. (The European Union has estimated the health care costs of these chemicals range into the hundreds of billions.) Just as no doctor can tell you how many cigarettes you can smoke before getting cancer, it’s tough to say what level of exposure to flame retardant chemicals will lead to potential ill effects. “The data we have argues for a strategy that reduces exposures,” Bradman says.

“The half life of some of these chemicals is five to seven years, meaning it takes that amount of time for the concentration of that chemical in your body to fall by 50 percent,” Stapleton adds. “And studies have shown that 90 percent of the American population has these flame retardant chemicals in their bodies.”

The good news is that newer laws have helped limit the use of flame-retardants in furniture. California updated TB117 in 2013 and again in 2014; the new regulations make it less likely that flame-retardant chemicals will be added to the filling materials of sofas and other household furniture items, Stapleton says.

That doesn’t mean newer couches can’t contain flame-retardants. But most manufacturers have phased out these chemicals, says Arlene Blum, executive director of the Green Science Policy Institute. Thanks to greater public awareness, and research showing couches don’t need to be infused with flame-retardants to be safe, “these chemicals are under control now in new furniture,” Blum says.

But in older couches, flame retardants are “pretty much always present,” Bradman says. “And as furniture gets older and materials break down, that could increase the transfer of these chemicals into the environment.”

Unfortunately, flame-retardants aren’t the only health concerns lurking in your sofa. Some anti-microbial treatments are also concerning, Blum says. So, too, are stain and water-repelling treatments. “These chemicals, particularly fluorinated compounds, never break down in the environment—never—and they’ve been linked with liver and kidney cancer, and reproductive and developmental problems,” Blum explains.

“Consumers love these [stain-repellant] treatments, but we’re concerned,” adds Linda Birnbaum, director of the National Institute of Environmental Health Sciences. “We don’t have adequate studies on the human health effects, but from animal studies we know some of these chemicals may have immunosuppressant and immunotoxic effects, and are also linked to cancer and developmental effects.”

Birnbaum says reforms to the Toxic Substances Control Act (TSCA) could lead to safer standards and more before-market testing of chemicals used in consumer goods. But as of today, it’s very difficult to keep all these chemicals out of your home and your body.

“It’s scary and it’s tough, because there are no simple ways to avoid these things,” Stapleton says.

She recommends asking lots of questions before buying a new piece of furniture. When it comes to stain-repellant and antimicrobial treatments, a lot of furniture sellers advertise those as perks or add-ons. So they’re often easy to spot, she says.

To avoid flame-retardants, check out a furniture piece’s label or tags. There may be information in a checked-box section stating that the item does not contain flame-retardants. Manufacturers or sellers should also be able to provide that info, she says.

Also, clean your floors and home frequently. “These chemicals adhere to dust particles,” she says. “So vacuuming more and washing your hands can help.” She also recommends laying down blankets to keep your small children (and any toys they may put in their mouths) off the floor.

As awareness of these chemicals dangers grows, it should become easier to find safe furniture pieces. The more consumers ask questions and demand chemical-free couches, the safer these products will become, Birnbaum says.

Contact us at letters@time.com.