Think twice before taking a seat.

From home furnishings to construction supplies, flame retardants are added to fabrics and other materials to slow the spread of fire. Despite being in common use since the 1970s, health experts have long known about the toxic threats associated with many such chemicals, including cancer and birth defects — and have phased out certain varieties as a result.

However, a new study to be published in the August issue of Environmental International has revealed that beloved broken-in couches may be shedding noxious dust in your home at alarming levels, according to researchers at the Silent Spring Institute.

“These are real risks,” said Kathryn Rodgers, a scientist and lead author. Studies have shown that these dangerous substances are associated with hormone disruption, immunosuppression, some cancers and, most concerningly, problems in fetal and early childhood development.

“When you look at some of these values, you say, that’s just a little bit of dust. A drop in the bucket,” she told Fast Company. But after many hours on the couch, she explained, “these exposures add up. They’re day in, day out. And they are real.”

What’s a sitter to do? Trash that vintage — or hand-me-down — sofa and get a modern model, researchers suggest.

Flame retardants became standard practice in 1975 after California — one of the largest furnishing markets in the country, according to Fast Company’s report — enacted law that required the additive in furniture manufacturing and imports. Soon, the foam material used to create couch cushions across the country was imbued with the provision.

By the early 2000s, scientists began to recognize the potential health risks, and, in 2013, California revised its standard, making the use of retardants in furniture manufacturing optional. In 2020, the federal government followed suit, supporting California’s ambiguous stance — meaning some factories continue to use retardants, though they’re increasingly avoidable.

To find out just how much damage old, chemical-laden couches are doing to American homes, Silent Sprint Institute researchers enlisted 42 households that were willing to have their old upholstered seats replaced. Dust samples were collected from these homes prior to the sofa swap, and again once the new seats arrived.

They found the initial samples packed with worrying concentrations of flame retardants, which are released into the indoor environment each time a body hits the cushion.

But with a new couch and six months in between, levels of toxic dust had sunk well within a safe margin, researchers discovered.

The findings suggest that couches manufactured after 2014 contain significantly lower levels of these harmful chemicals, and consumers would be wise to shop for seating produced after that date.

Also, keep an eye out for the code “TB117-2013” on the furniture tag, which indicates the piece was made after California’s standards shifted. In some cases, the description states more definitively whether the material contains flame retardants with a “yes” or “no” indicated as confirmation.

In the past, the American Chemical Council has claimed that adding these chemicals to furniture has prevented some 360 deaths and 740 injuries each year. But the jury is out for Rodgers, who explained that better product design has made flame retardants almost obsolete.

“[They] didn’t make sense from a fire safety perspective — because fires don’t start from the middle of your couch,” she said.