{"url":"https://whatshealthyandwhy.com/flame-retardants/health-effects-and-exposure","path":"/flame-retardants/health-effects-and-exposure","alternates":{"json":"https://whatshealthyandwhy.com/api/articles/flame-retardants/health-effects-and-exposure.json","markdown":"https://whatshealthyandwhy.com/flame-retardants/health-effects-and-exposure.md"},"topic":{"slug":"flame-retardants","name":"Flame Retardants","url":"https://whatshealthyandwhy.com/flame-retardants"},"slug":"health-effects-and-exposure","order":1,"title":"Flame Retardants: Hidden Toxins in Your Home","question":"Are flame retardants in furniture bad for you?","answer":"Older PBDE flame retardants are likely harmful in pregnancy and childhood, linked to lower IQ and thyroid changes; newer replacements have little human data.","description":"How flame retardant chemicals in furniture, electronics, and textiles accumulate in the body and disrupt hormones, brain development, and cellular health","confidence":3,"confidenceNote":"Cohorts of 309 and 270 pregnant women link PBDEs to lower IQ and thyroid changes; a 61-study review is inconsistent on thyroid direction.","evidenceSummary":{"rctCount":1,"observationalCount":3,"metaAnalysisCount":1,"totalParticipants":"600+","replicated":true,"newestStudyYear":2024},"category":{"categoryTitle":"What's Harming You","categorySlug":"harming-you","subcategoryName":"Environmental Toxins","subcategorySlug":"environment","url":"https://whatshealthyandwhy.com/explore/harming-you/environment"},"actions":["Wash hands often, especially before eating; in a two-week trial this cut a flame-retardant urine metabolite by about half [6].","Wet-mop and HEPA-vacuum floors rather than dry sweeping; standard vacuums can aerosolize fine dust [6].","When replacing furniture, look for a TB117-2013 label, which dropped the chemical treatment requirement; do not cut or reupholster old foam."],"cautions":["Pregnant women and young children are most vulnerable; children are especially exposed through floor dust and hand-to-mouth contact [5].","Furniture made before 2015 may still contain PBDEs; if you cannot replace it, intact foam is lower-risk than worn or crumbling pieces.","Replacement chemicals such as TDCPP are not proven safer: lab data show DNA damage in human liver cells, and human data are sparse [4]."],"simpleText":"Flame retardants are synthetic chemicals added to foam furniture, electronics, car interiors, and some textiles to slow ignition. They sound protective, but decades of research show they migrate out of products into house dust — and from dust into our bodies — where they interfere with thyroid hormones, impair brain development in children, and may cause DNA damage. The main concern is not that you'll catch fire without them, but that you're living with them every day [1][2].","mediumText":"How Flame Retardants Enter Your Body\n\nThe primary route is house dust. Flame retardants slowly volatilize from treated foam and plastics, binding to airborne particles that settle on floors and surfaces. You ingest this dust through normal hand-to-mouth contact and breathing — a route that particularly affects young children who crawl on floors and frequently put hands to mouths [5].\n\nThe older class of flame retardants, polybrominated diphenyl ethers (PBDEs), were used in furniture foam from the 1970s until voluntary phase-outs between 2004 and 2013. Despite those phase-outs, PBDE-laden furniture made before 2015 remains in millions of American homes. U.S. body burden levels are 10–40 times higher than European levels, largely because of aggressive U.S. flammability standards — particularly California's TB117 rule, which required foam cushions to withstand an open flame for 12 seconds and drove widespread chemical treatment [5].\n\nSince the PBDE phase-out, manufacturers largely switched to organophosphate flame retardants (OPFRs) such as TDCPP and TCIPP. These replacements are now detectable in the urine of over 90% of U.S. adults.\n\nWhere flame retardants accumulate:\n- Upholstered sofas, chairs, and mattress foam (the largest residential source)\n- Printed circuit boards and plastic casings in electronics\n- Car seats, dashboards, and headliners — car dust is among the most concentrated indoor sources\n- Children's carpet underlays and some clothing\n\nWhy They Disrupt Thyroid Hormones\n\nPBDEs are structurally similar to thyroid hormones T3 and T4. The bromine atoms on their molecular backbone mimic the iodine atoms on thyroid hormone, allowing them to bind to thyroid transport proteins (transthyretin, TBG) and partially displace circulating hormones. They also induce liver enzymes that speed up thyroid hormone breakdown, reducing T4 levels even further [2][3].\n\nA study of 270 pregnant women found that each 10-fold increase in serum PBDE concentration was associated with an 11–19% decrease in TSH, a marker of disrupted thyroid signaling [2]. A 2024 systematic review of 61 studies confirmed the pattern, noting that pregnant women, children, firefighters, and e-waste workers face the highest risk of thyroid-disrupting exposure [3].\n\nThis matters enormously during pregnancy: thyroid hormone drives fetal brain development. Even modest maternal thyroid disruption during the first trimester — before the fetal thyroid is functional — can permanently alter neurodevelopment.\n\nNeurodevelopment in Children\n\nThe HOME study, a long-running prospective cohort in Cincinnati, measured prenatal PBDE levels in 309 pregnant women and followed their children to age 5. Each 10-fold increase in prenatal BDE-47 (the most common PBDE congener) was associated with a 4.5-point decrease in full-scale IQ and a 3.3-point increase in hyperactivity scores at age 5 [1]. The effects weren't apparent at ages 1–3 but emerged clearly as more complex cognitive functions developed.\n\nFor context, lead exposure — the canonical neurodevelopmental toxin — produces roughly 1–5 IQ points of loss per 10 µg/dL blood lead increase. PBDE effects are in a similar range. These are not trivial changes at a population level; a 4-5 point shift in the IQ distribution affects learning capacity, educational attainment, and lifetime earnings across entire birth cohorts.\n\nThe New Replacements Are Also Concerning\n\nTDCPP (tris(1,3-dichloro-2-propyl) phosphate), one of the OPFRs that replaced PBDEs in foam furniture, was listed as a probable carcinogen by the State of California. A 2022 laboratory study found TDCPP caused DNA strand breaks, increased oxidative stress, triggered apoptosis, and upregulated 11 cancer-pathway genes in human liver cells — providing a cellular mechanism consistent with animal carcinogenicity data [4].\n\nThis is the core problem with flame retardant policy: chemicals are phased out after evidence of harm accumulates, then replaced with structurally different but mechanistically similar compounds, restarting the cycle.\n\nPractical Ways to Reduce Exposure\n\nA behavioral intervention study tested which everyday actions actually reduced OPFR and PBDE metabolites in urine and blood. Within two weeks, the following made a measurable difference [6]:\n\nMost impactful:\n- Frequent hand washing, especially before eating — reduced metabolites of some flame retardants by approximately 50% within one week\n- HEPA vacuuming and wet mopping floors — reduces dust loading (standard vacuum cleaners can aerosolize fine dust, worsening exposure)\n\nLonger-term reductions:\n- Replace pre-2015 upholstered furniture — this is the single largest source in most homes; if replacement isn't feasible, intact furniture with no visible foam degradation is lower-risk than worn or crumbling pieces\n- Do not reupholster old foam — cutting and disturbing old foam dramatically releases accumulated chemicals\n- Check furniture labels for \"TB117-2013\" compliance — the 2013 revision of California's standard removed the chemical treatment requirement; furniture labeled with the updated standard may be chemical-free\n- Improve ventilation — opening windows regularly dilutes indoor air; flame retardants volatilize slowly from treated materials at room temperature\n\nFor children specifically:\n- Wash hands frequently and before snacks\n- Use a damp cloth to clean floors and play surfaces rather than dry sweeping\n- Prefer wooden, cotton-stuffed, or wool-stuffed toys over polyurethane foam toys\n\nSee our phthalates page for similar information on another class of hormone-disrupting chemicals found in flexible plastics. See also our mattresses and furniture page for guidance on choosing lower-exposure home furnishings.","deepText":"Evidence Review\n\nNeurodevelopmental Effects: The HOME Cohort\n\nChen et al. (2014) [1] is among the most methodologically rigorous studies linking prenatal PBDE exposure to IQ deficits. The Health Outcomes and Measures of the Environment (HOME) study enrolled 309 mother-infant pairs in Cincinnati, Ohio, measured maternal serum PBDEs at ~16 weeks' gestation, and administered standardized cognitive and behavioral assessments at 1, 2, 3, and 5 years. The primary finding — a 4.5-point full-scale IQ decrease per 10-fold increase in prenatal BDE-47 — was statistically significant (95% CI: -7.8 to -1.2). Hyperactivity index scores also increased by 3.3 points (95% CI: 0.7 to 5.9). Critically, no significant associations were seen at ages 1–3, suggesting effects emerge as more complex frontal and executive functions develop. Limitations: single cohort, primarily white, Midwestern population; cannot rule out residual confounding from co-exposures. However, the finding replicates across multiple independent U.S. and European cohorts.\n\nThyroid Hormone Disruption in Pregnancy\n\nChevrier et al. (2010) [2] measured serum concentrations of seven PBDE congeners in 270 pregnant women at ~27 weeks gestation alongside thyroid hormones (TSH, T4, T3, thyroid antibodies). Each 10-fold increase in BDE-28 was associated with a 10.9% decrease in TSH (p < 0.05); BDE-153 was associated with an 18.7% decrease. The direction of effect — lower TSH — is paradoxical, as classic thyroid disruption typically elevates TSH. The authors propose direct pituitary inhibition as a mechanism, noting that PBDE structural mimicry of thyroid hormone could suppress the TSH-releasing feedback loop. Study size is moderate; findings have been replicated in multiple subsequent cohort studies, including Norwegian Mother and Child Cohort data.\n\nSystematic Review: Flame Retardants and Thyroid Function (2024)\n\nYeshoua et al. (2024) [3] reviewed 61 studies across multiple flame retardant classes (PBDEs, OPFRs, HBCD, TBBPA). Results were heterogeneous: 10 studies found positive associations between PBDE exposure and TSH, 6 found negative, and several found null results. Heterogeneity likely reflects variation in timing of exposure measurement, which PBDE congeners were analyzed, and thyroid parameter measured. Despite inconsistency in direction, the review concludes that the weight of evidence supports endocrine-disrupting activity and that vulnerable populations — particularly pregnant women and children — warrant a precautionary approach. No conflicts of interest declared.\n\nTDCPP Genotoxicity: Cellular Evidence\n\nSaquib et al. (2022) [4] exposed human hepatocellular carcinoma cells (HepG2) to TDCPP at concentrations ranging from 3.1 to 50 µg/mL for 24 hours. Results showed concentration-dependent increases in DNA strand breaks (comet assay), ROS generation, mitochondrial membrane disruption, and caspase-3/7 activation indicating apoptosis. Gene expression profiling revealed upregulation of 11 genes in cancer-related pathways including p53 signaling, cell cycle arrest, and apoptosis induction. While in vitro data cannot establish human cancer risk on their own, these findings provide a mechanistic basis for the California probable carcinogen classification and animal bioassay results. TDCPP is now found in essentially all U.S. home dust samples following the PBDE phase-out.\n\nExposure Sources: California Furniture Standards and Body Burden\n\nZota et al. (2008) [5] measured PBDE concentrations in house dust and resident serum from 13 California homes alongside reference data from non-California U.S. homes and European homes. Median dust concentrations in California were 4–10 times higher than elsewhere in North America, and California residents' median serum PBDE levels were approximately 1.6–2.0 times higher than non-Californian U.S. residents. The authors directly attribute this to California's TB117 standard (effective 1975, revised 2013), which required furniture foam to self-extinguish after 12 seconds of open-flame exposure — a standard achievable only with substantial chemical treatment. This is a landmark source-attribution study; the 2013 revision to TB117 removed the chemical requirement, but the legacy furniture problem persists.\n\nBehavioral Interventions: What Actually Works\n\nGibson et al. (2019) [6] enrolled 32 New York City mother-child pairs in a two-week crossover intervention. Participants were randomized to hand washing, house cleaning, combined, or no intervention. Urine and serum samples were collected at baseline, week 1, and week 2. Hand washing alone reduced BDCIPP (a TDCPP urinary metabolite) by approximately 47% by week 1 (95% CI: 27–62%). Wet mopping produced comparable reductions in floor dust concentration. The combined intervention produced no statistically significant additional benefit over hand washing alone. Effect sizes were largest in participants with highest baseline exposure. This study directly informs practical public health messaging and demonstrates that exposure reduction is feasible without eliminating source materials.\n\nEvidence Summary\n\nEndpoint | Studies | Strength\n\nThyroid hormone disruption | Multiple cohorts, systematic review | Moderate-Strong\nIQ/cognitive deficits in children | Multiple cohorts including HOME | Strong\nADHD/hyperactivity | Several epidemiological studies | Moderate\nDNA damage/genotoxicity (TDCPP) | In vitro, animal | Moderate (limited human data)\nHand washing reduces exposure | Randomized intervention | Strong\n\nThe overall evidence profile for PBDEs — particularly for thyroid disruption and neurodevelopmental effects — is among the stronger in environmental toxicology, comparable to the lead and mercury literatures. The newer OPFRs have less human data but concerning early mechanistic findings. The phase-out-and-replace pattern means this will remain an active area of research as new replacement chemicals enter wide use.","deepTruncated":false,"references":[{"id":"1","title":"Prenatal polybrominated diphenyl ether exposures and neurodevelopment in U.S. children through 5 years of age: the HOME study","authors":"Chen A, Yolton K, Rauch SA, Webster GM, Hornung R, Sjödin A, Dietrich KN, Lanphear BP","year":2014,"journal":"Environmental Health Perspectives","pmid":"24870060","url":"https://pubmed.ncbi.nlm.nih.gov/24870060/"},{"id":"2","title":"Polybrominated diphenyl ether (PBDE) flame retardants and thyroid hormone during pregnancy","authors":"Chevrier J, Harley KG, Bradman A, Gharbi M, Sjödin A, Eskenazi B","year":2010,"journal":"Environmental Health Perspectives","pmid":"20562054","url":"https://pubmed.ncbi.nlm.nih.gov/20562054/"},{"id":"3","title":"A Review of the Association between Exposure to Flame Retardants and Thyroid Function","authors":"Yeshoua B, Romero Castillo H, Monaghan M, van Gerwen M","year":2024,"journal":"Biomedicines","pmid":"38927574","url":"https://pubmed.ncbi.nlm.nih.gov/38927574/"},{"id":"4","title":"Organophosphorus Flame Retardant TDCPP Displays Genotoxic and Carcinogenic Risks in Human Liver Cells","authors":"Saquib Q, Al-Salem AM, Siddiqui MA, Ansari SM, Zhang X, Al-Khedhairy AA","year":2022,"journal":"Cells","pmid":"35053312","url":"https://pubmed.ncbi.nlm.nih.gov/35053312/"},{"id":"5","title":"Elevated house dust and serum concentrations of PBDEs in California: unintended consequences of furniture flammability standards?","authors":"Zota AR, Rudel RA, Morello-Frosch RA, Brody JG","year":2008,"journal":"Environmental Science and Technology","pmid":"19031918","url":"https://pubmed.ncbi.nlm.nih.gov/19031918/"},{"id":"6","title":"Flame retardant exposure assessment: findings from a behavioral intervention study","authors":"Gibson EA, Stapleton HM, Calero L, Holmes D, Burke K, Martinez R, Cortes B, Nematollahi A, Evans D, Herbstman JB","year":2019,"journal":"Journal of Exposure Science and Environmental Epidemiology","pmid":"29950671","url":"https://pubmed.ncbi.nlm.nih.gov/29950671/"}],"wordCount":1690,"source":{"path":"src/content/topics/flame-retardants/health-effects-and-exposure.md"},"citeAs":"“Are flame retardants in furniture bad for you?.” What's Healthy and Why. https://whatshealthyandwhy.com/flame-retardants/health-effects-and-exposure","notice":"General information backed by peer-reviewed research, not medical advice."}