<p class="first" id="P1">Polyurethane foam (PUF) in upholstered furniture frequently
is treated with flame
retardant chemicals (FRs) to reduce its flammability and adhere to rigorous flammability
standards. For decades, a commercial mixture of polybrominated diphenyl ethers (PBDEs)
called PentaBDE was commonly applied to foam to fulfill these regulations; however,
concerns over toxicity, bioaccumulation, and persistence led to a global phase-out
in the mid-2000s. Although PentaBDE is still detected in older furniture, other FR
compounds such as tris(1,3-dichloroisopropyl) phosphate (TDCIPP) and Firemaster® 550
(FM550) have been increasingly used as replacements. While biomonitoring studies suggest
exposure is widespread, the primary sources of exposure are not clearly known. Here,
we investigated the relationships between specific FR applications in furniture foam
and human exposure. Paired samples of furniture foam, house dust and serum samples
were collected from a cohort in North Carolina, USA and analyzed for FRs typically
used in PUF. In general, the presence of a specific FR in the sofa of a home was associated
with an increase in the concentration of that FR in house dust. For example, the presence
of PentaBDE in sofas was associated with significantly higher levels of BDE-47, a
major component of PentaBDE, in house dust (10
<sup>β</sup>=6.4, p<0.001). A similar association was observed with a component
of FM550, 2-ethylhexyl-2,3,4,5-tetrabromobenzoate
(EH-TBB), with levels that were approximately 3 times higher in house dust when FM550
was identified in the sofa foam (p<0.01). These relationships were modified by
dust
loading rates in the living room and the ratio of sofa size to room size. Interestingly,
levels of TDCIPP and tris(1-chloro-2-isopropyl) phosphate (TCIPP) were also higher
in dust with detections in sofa foam; however, these associations were not statistically
significant and may suggest there are other prominent sources of these compounds in
the home. In addition, the presence of PentaBDE in sofa foam was associated with significantly
higher levels of BDE-47 in serum (p<0.01). These results suggest that FR applications
in sofas are likely major sources of exposure to these compounds in the home.
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