Fire retardant refers to any substance or chemical treatment that slows down or stops the spread of fire. Rather than making something fireproof, a fire retardant reduces how quickly flames grow, buying time before a material fully ignites. You’ll find fire retardants in everything from couch cushions and mattresses to the plastic casing of your laptop.
Fire Retardant vs. Fire Resistant
These two terms get used interchangeably, but they describe different things. A fire-retardant material has been chemically treated with a coating or additive designed to slow flame spread. You can apply fire-retardant treatments to wood, fabrics, carpets, and curtains. The chemical coating helps extinguish flames if they come into contact with the treated surface.
A fire-resistant material, on the other hand, can naturally withstand high temperatures before it starts to burn. Wool, for example, is fire resistant because it only ignites at very high temperatures without any chemical treatment. Some fire-resistant materials are also treated with chemicals to make them even stronger, which is where the two categories overlap and the terminology gets confusing.
How Fire Retardants Actually Work
Fire needs three things: fuel, heat, and oxygen. Fire retardants work by disrupting one or more of those elements, and they do it through a few different mechanisms that can work alone or in combination.
The most straightforward mechanism is heat absorption. When a fire-retardant material gets hot, the chemicals undergo a strong cooling reaction that absorbs some of the heat released by the flames. This can keep the material’s temperature below its ignition point long enough to prevent full combustion.
A second mechanism involves starving the fire of oxygen. At high temperatures, fire-retardant chemicals break down and release non-flammable gases. As these gases build up around the burning surface, they dilute the oxygen and flammable vapors in the immediate area, effectively suffocating the fire.
Some retardants also work by forming a protective carbon layer on the material’s surface. This char acts like a shield, blocking heat from reaching the underlying material and preventing flammable gases from escaping to feed the flames. Others interrupt the chemical chain reaction that sustains combustion itself, neutralizing the reactive molecules that keep a fire going.
Types of Fire Retardant Chemicals
Fire retardants fall into several broad chemical families, each with different properties and trade-offs.
- Brominated compounds were the most widely used flame retardants from the 1970s through the early 2000s. They’re highly effective but have faced bans and phase-outs due to health and environmental concerns.
- Chlorinated compounds work similarly to brominated ones and share many of the same concerns about persistence in the environment.
- Phosphorus-based compounds are increasingly common as replacements for brominated chemicals. They typically work by promoting char formation on the material’s surface.
- Nitrogen-based compounds often release non-flammable gases when heated, diluting oxygen around the flame.
Many modern flame retardants combine two or more of these chemical families to improve performance. The U.S. EPA maintains an inventory of hundreds of individual flame retardant chemicals currently in use.
Where Fire Retardants Show Up in Your Home
Since the 1970s, fire retardant chemicals have been added to a wide range of consumer products. The National Institute of Environmental Health Sciences identifies three major categories: furnishings (seating foam, mattresses, carpets, and vehicle upholstery), electronics (computers, phones, televisions, and household appliances), and building materials (wire coatings, polystyrene foams, and spray-on insulation).
The polyurethane foam inside couch cushions has historically been one of the biggest sources of flame retardant chemicals in homes. Over time, these chemicals migrate out of the products they’re added to and accumulate in household dust. Research has found legacy and newer flame retardants in dust samples across indoor environments, and dust ingestion is a major exposure pathway for both toddlers and adults. Young children face higher relative exposure because they spend more time on floors and put their hands in their mouths more often.
Health Concerns
Not all fire retardants carry the same risks, but several widely used classes have raised serious health concerns, particularly around hormonal disruption. Brominated flame retardants are structurally similar to thyroid hormones, which means they can interfere with thyroid function. In rodent studies, exposure to these chemicals reduces circulating levels of key thyroid hormones. Human studies have shown mixed results, with some finding increased thyroid hormone levels and others finding no significant change, but the concern is real enough that multiple formulations have been pulled from the market.
Chlorinated flame retardants have also been linked to thyroid disruption. One human study found that high concentrations of a common chlorinated retardant in house dust were associated with decreased thyroid hormone levels in men. In fish and chicken embryos, the same chemical altered thyroid hormone levels and changed the expression of genes that regulate thyroid function. Some newer replacement chemicals show similar patterns of hormonal disruption, affecting reproductive and thyroid systems.
A key problem is that many of these chemicals persist in the body for years. Some brominated compounds have half-lives of 2 to 4 years in humans, meaning it takes that long for your body to eliminate just half of what it absorbed. One specific compound, BDE-153, has an estimated half-life of 14 to 16 years. Polybrominated biphenyls, an older class now banned, have a half-life of nearly 11 years.
Regulation and Labeling
The regulatory landscape around flame retardants has shifted significantly. Older brominated formulations were voluntarily phased out of the U.S. market between 2004 and 2013 after studies confirmed their presence in environmental samples and human tissues, along with evidence of neurotoxicity and hormone disruption. Some replacements, like TBBPA and HBCD, remain in production but face heavy scrutiny for similar reasons.
For furniture specifically, U.S. federal standards require upholstered furniture to carry a permanent label stating it complies with CPSC flammability requirements. The federal standard does not require or prohibit the use of flame retardant chemicals to meet its flammability tests, meaning manufacturers can use barrier fabrics or other design approaches instead. California goes a step further with its SB-1019 law, which requires manufacturers to disclose on the label whether flame retardant chemicals were added to the product. If you’re trying to avoid added chemicals in furniture, California’s disclosure labels are currently the most reliable way to check.