Novel and high volume use flame retardants in US couches reflective of the 2005 PentaBDE phase out

Abstract

California's furniture flammability standard Technical Bulletin 117 (TB 117) is believed to be a major driver of chemical flame retardant (FR) use in residential furniture in the United States. With the phase-out of the polybrominated diphenyl ether (PBDE) FR mixture PentaBDE in 2005, alternative FRs are increasingly being used to meet TB 117; however, it was unclear which chemicals were being used and how frequently. To address this data gap, we collected and analyzed 102 samples of polyurethane foam from residential couches purchased in the United States from 1985 to 2010. Overall, we detected chemical flame retardants in 85% of the couches. In samples purchased prior to 2005 (n = 41) PBDEs associated with the PentaBDE mixture including BDEs 47, 99, and 100 (PentaBDE) were the most common FR detected (39%), followed by tris(1,3-dichloroisopropyl) phosphate (TDCPP; 24%), which is a suspected human carcinogen. In samples purchased in 2005 or later (n = 61) the most common FRs detected were TDCPP (52%) and components associated with the Firemaster550 (FM 550) mixture (18%). Since the 2005 phase-out of PentaBDE, the use of TDCPP increased significantly. In addition, a mixture of nonhalogenated organophosphate FRs that included triphenyl phosphate (TPP), tris(4-butylphenyl) phosphate (TBPP), and a mix of butylphenyl phosphate isomers were observed in 13% of the couch samples purchased in 2005 or later. Overall the prevalence of flame retardants (and PentaBDE) was higher in couches bought in California compared to elsewhere, although the difference was not quite significant (p = 0.054 for PentaBDE). The difference was greater before 2005 than after, suggesting that TB 117 is becoming a de facto standard across the U.S. We determined that the presence of a TB 117 label did predict the presence of a FR; however, lack of a label did not predict the absence of a flame retardant. Following the PentaBDE phase out, we also found an increased number of flame retardants on the market. Given these results, and the potential for human exposure to FRs, health studies should be conducted on the types of FRs identified here.

Figure 1

GC/MS total ion chromatogram from an extract of polyurethane foam treated with a mixture (TBPP mix) of aromatic phosphates including triphenyl phosphate (TPP) (1), 4-(tert-butyl)phenyl diphenyl phosphate (2), bis(4-(tert-butyl)phenyl) phenyl phosphate (3), and tris(4-(tert-butyl)phenyl phosphate (TBPP) (4). Structures 2 and 3 are hypothesized based on high resolution mass spectrometry analysis and the confirmation of structure 4.

Figure 2

GC/MS total ion chromatogram from an extract of polyurethane foam treated with a mixture of aromatic phosphates including triphenyl phosphate (TPP) (1), two isomers of methylphenyl diphenyl phosphate (2), and two isomers of bis(methylphenyl) phenyl phosphate (3). Structures 2 and 3 are hypothesized based on comparison to NIST Mass Spectral Database (2005) and high resolution mass spectrometry analysis. The position of the methyl groups has not yet been determined.