At a glance
| Chemical family | Brominated flame retardant — tetrabromobenzoate ester (Firemaster 550 component) |
| CAS number | 183658-27-7 |
| Classification | Not IARC classified. Metabolises to TBBA (detected in human urine). Antiestrogenic and steroidogenic activity in vitro. Rising in house dust as a PBDE replacement |
| Where you encounter it | Polyurethane foam in furniture and mattresses (as Firemaster 550 component); house dust (rising concentrations); detected in indoor air |
| Sleep micro-environment relevance | Found in house dust at increasing concentrations from FM550-treated foam products. Metabolite TBBA detected in human urine confirms systemic exposure. Direct exposure from mattress foam during sleep |
Regulatory & certification status
| European Union | Not individually restricted. Not on the SVHC candidate list. REACH registration status linked to the FM550 mixture components. Regulatory |
| United States | Not individually restricted. Included in the broader EPA assessment of organophosphate and brominated FRs in foam. TSCA inventory listed. Regulatory |
| Canada | Under assessment as part of the Chemicals Management Plan flame retardant grouping. Regulatory |
| International | Not IARC classified. Not a Stockholm Convention POP. Identified in house dust globally. Metabolite TBBA confirmed in human biomonitoring studies. Regulatory |
What it is
TBB is a brominated benzoate ester — one of two brominated components of Firemaster 550 (the other being TBPH). It was identified in house dust and foam products starting in 2008 when researchers began characterising the composition of the FM550 mixture. TBB is metabolised in the body to TBBA (tetrabromobenzoic acid), which has been detected in urine from the general population. This confirms that exposure through house dust and direct contact with treated foam leads to systemic absorption. The in vitro evidence points the opposite way to the one people expect. Saunders et al. 2013 ran TBB through yeast reporter and H295R steroidogenesis assays and found no estrogen- or androgen-mimicking activity and no dioxin-like effect. What it did produce was an antiestrogenic response — a maximal 62% effect at 0.5 mg/L — and a 2.8-fold rise in estradiol output from the steroid-producing cells at 0.05 mg/L. TBB interferes with hormone signalling, but by blocking and by shifting hormone production, not by imitating estrogen. TBB is not individually regulated in any jurisdiction — regulatory attention has focused on the FM550 mixture and on the organophosphate components (TPHP) rather than TBB specifically.
Where it shows up in bedding
TBB enters the bedroom through polyurethane foam in mattresses and furniture treated with Firemaster 550. Like the organophosphate components of FM550, TBB migrates from foam to dust over time as the foam ages and degrades. TBB has been detected in house dust in homes across North America and Europe, with concentrations rising as PBDE-treated furniture is replaced. During sleep, exposure occurs through dust ingestion, dermal contact with contaminated surfaces, and inhalation. Detection of the metabolite TBBA in human urine confirms that dust-borne TBB is absorbed into the body. The co-occurrence of TBB with TPHP, IPTPP, and EHDPP in dust from the same FM550 source means exposure is to the mixture, not individual compounds in isolation.
The Embr Exposure Ledger: 2-Ethylhexyl-2,3,4,5-tetrabromobenzoate
One chemical, several public questions, answered from independent datasets and joined here — the environment it shows up in, the body burden it carries, how it is regulated, and what actually reduces it.
Detection and body-burden figures are occurrence data, not a personal measurement or a health diagnosis. Part of the Embr Exposure Ledger — an open, cross-dataset chemical join (download the data), reusable with attribution.
Citations
- Stapleton, H.M. et al. (2008). Alternate and new brominated flame retardants detected in U.S. house dust. House Dust. Environmental Science & Technology, 42(18): 6910-6916. Source Peer-reviewed
- Saunders, D.M. et al. (2013). In vitro endocrine disruption and TCDD-like effects of three novel brominated flame retardants: TBPH, TBB, & TBCO. Toxicology Letters, 223(2): 252-259. PMID 24064184 Peer-reviewed
- EPA (2015). Flame Retardants Used in Flexible Polyurethane Foam: Alternatives Assessment. Source Regulatory
Frequently asked questions
What is TBB and where does it come from?
TBB (2-ethylhexyl-2,3,4,5-tetrabromobenzoate) is a brominated flame retardant that is one component of the Firemaster 550 mixture used in polyurethane foam furniture and mattresses. It was identified in house dust by researchers studying what replaced PBDEs in foam. TBB migrates from foam to dust over time as products age.
Has TBB been detected in people?
Yes. TBB metabolises in the body to TBBA (tetrabromobenzoic acid), which has been detected in human urine samples from the general population. This confirms that exposure to TBB through house dust and direct contact with treated foam leads to systemic absorption. The health significance of these body burdens is under investigation.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-07-08. If you find a factual error, contact us.