A flame retardant is a chemical added to materials to slow down or prevent them from catching fire. These chemicals work by interfering with combustion, the process that allows fire to spread, and they’re found in everything from couch cushions to electronics to children’s pajamas. While they do reduce fire risk, many flame retardants have raised serious health and environmental concerns over the past two decades, leading to bans and phase-outs of some of the most widely used types.
How Flame Retardants Stop Fire
Fire needs three things: fuel, heat, and oxygen. Flame retardants work by disrupting one or more of these. Some trigger a strong endothermic (heat-absorbing) reaction, pulling heat away from the burning material so it can’t sustain combustion. Others release gases that form an invisible barrier between the flame and the material’s surface, diluting the oxygen supply. A third approach involves forming a non-combustible protective layer, essentially a char coating, that shields the underlying material from heat and cuts off its fuel supply.
Most flame retardants use a combination of these physical and chemical strategies. They don’t make a material fireproof. Instead, they slow ignition and reduce how quickly flames spread, which can buy critical seconds during a fire.
Common Types of Flame Retardants
There are hundreds of different flame retardant chemicals, typically grouped by their core ingredient:
- Bromine-based: The most widely used class historically. These chemicals interrupt the chemical reactions that sustain a flame. Many have been phased out due to health concerns, but they persist in older products and the environment.
- Chlorine-based: Similar in function to bromine-based retardants and also associated with environmental persistence.
- Phosphorus-based: These promote the formation of a protective char layer on a material’s surface. They’ve become more common as replacements for brominated chemicals.
- Nitrogen-based: Often used in combination with phosphorus compounds, these release inert gases that dilute flammable vapors.
- Mineral-based: Compounds containing metals or boron that absorb heat and release water vapor. Generally considered less toxic than organic flame retardants.
Where You’ll Find Them
Flame retardants are embedded in a surprisingly wide range of everyday products. Polyurethane foam, the material inside most couch cushions and mattresses, has historically been one of the biggest carriers. Electronics casings, circuit boards, and wire insulation commonly contain them. Building insulation, carpet padding, and curtains may be treated as well. Children’s products, including car seats and nap mats, have also contained these chemicals, though many manufacturers have moved away from them in recent years.
The chemicals can be either mixed into a material during manufacturing or chemically bonded to it. When they’re simply mixed in rather than bonded, they migrate out of the product more easily, ending up in household dust, indoor air, and eventually in your body.
Health Concerns
The National Institute of Environmental Health Sciences links flame retardant exposure to a list of health effects that includes endocrine and thyroid disruption, reproductive toxicity, immunotoxicity, and cancer. Evidence also connects exposure to neurodevelopmental problems, particularly in children. Animal studies show neurotoxic effects, and the fact that the general population faces chronic, low-level exposure raises concern about cumulative harm to brain development across all age groups.
Brominated flame retardants have drawn the most scrutiny. They’ve been specifically linked to thyroid dysfunction, which matters because thyroid hormones play a central role in brain development during pregnancy and early childhood. Learning disabilities, hyperactivity, and behavioral changes have all been associated with exposure. Young children face higher risk because they spend more time on the floor, put objects in their mouths, and have developing systems that are more vulnerable to chemical disruption.
How They Build Up in the Environment
Flame retardants escape into the environment through multiple routes: factory wastewater, volatilization from products during normal use, breakdown of foam in old furniture, leaching from landfills, and attachment to dust particles that travel far from their original source. Brominated flame retardants have been detected in indoor and outdoor air, household dust, soil, and waterways.
Once in the environment, some of these chemicals bioaccumulate, meaning they build up in living organisms and concentrate as they move up the food chain. Researchers have found increasing concentrations in zooplankton, fish, and marine mammals. This food chain accumulation is one of the primary ways humans are exposed: through eating contaminated fish, meat, eggs, and dairy products. Brominated flame retardants have been detected in human blood serum, body tissues, and breast milk, both in people who work directly with these chemicals and in the general population.
Regulatory Status in the U.S.
The most well-known group of flame retardants, polybrominated diphenyl ethers (PBDEs), has been largely phased out in the United States. Two major types, penta- and octaBDE, were phased out of manufacturing and import in 2004. A third type, decaBDE, followed with a voluntary industry phase-out completed by the end of 2013. Despite these actions, PBDEs continue to be detected in people and the environment because they persist for years in existing products, dust, and ecosystems.
Replacement chemicals have filled the gap, but many of them are also drawing concern. Some phosphorus-based replacements, for example, have shown similar endocrine-disrupting properties. The regulatory landscape continues to shift as health data accumulates on newer formulations.
How to Identify Treated Products
Knowing whether a product contains flame retardants is harder than you might expect. California requires all upholstered furniture sold in the state to carry a flammability label, but this label only confirms the product meets a fire safety performance standard. It does not tell you whether flame retardant chemicals were used. Manufacturers are not required to disclose the presence of these chemicals on the label, though California’s Proposition 65 may require a separate notice in some cases.
Some manufacturers now voluntarily label their products as “contains no added flame retardants,” which has become a selling point for furniture and mattress companies. If a label is absent or unclear, contacting the manufacturer directly is often the only way to get a definitive answer.
Reducing Your Exposure
Because flame retardants accumulate in household dust, regular cleaning is the most effective way to lower exposure at home. Vacuuming with a HEPA-filter vacuum traps the fine dust particles that carry these chemicals, while a standard vacuum can push them back into the air. Wet mopping hard floors and wiping surfaces with a damp cloth captures dust that vacuuming misses.
Handwashing matters more than you might think, especially for children. Flame retardant-laden dust sticks to hands and transfers to food and mouths throughout the day. Washing hands before meals and after playing on the floor significantly reduces ingestion. When replacing old furniture, particularly pieces with crumbling or exposed foam, choosing products marketed as free of added flame retardants can reduce the chemical load in your home over time. Keeping foam-containing products intact, with covers and cushion casings in good condition, also limits how much chemical-carrying dust they shed.