Nomination Date: 04/28/2013
Nominator: Private Individual
Rationale: Firemaster 550 (FM 550) is a proprietary flame retardant (FR) mixture composed of: (i) triphenyl phosphate; (ii) several isopropylated triphenyl phosphates; (iii) 2-ethylhexyl-2,3,4,5-tetrabromobenzoate; and (iv) bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH) (Stapleton et al. Environ Sci Technol 2008;42:6910-16). After the FR pentabromodiphenylether was banned in several states and phased out of production less than a decade ago, FM 550 began to be used in increasing quantities in upholstered furniture, infant products and other items, so that it has become one of the most commonly detected FRs in the U.S. (Dodson et al. Environ Sci Technol 2012;46:13056-66; Stapleton et al. Environ Sci Technol 2011;45:5323-31; Stapleton et al. Environ Sci Technol 2012;46:13432-39). As with many other FRs, FM 550 components migrate from the products to which they are added, and have been detected in house dust, sewage sludge, and marine mammals (Stapleton et al. Environ Sci Technol 2008;42:6910-16; Davis et al. Environ Int 2012:40:1-7; Lam et al. Environ Sci Technol 2009;43:6944-49). To date (4/27/13), a PubMed search for the term "Firemaster 550" returns seven citations, only one of which is a mammalian toxicity investigation of this mixture (Patisaul et al., J Biochem Mol Toxicol 2013;27:124-36). That study found that FM 550 components accumulated in pregnant rats and their offspring, and exposure to the mixture was also associated with increased circulating thyroid hormone and reduced hepatic carboxylesterase activity in the dams. In the offspring, FM 550 exposure in utero and via lactation was associated with early female puberty, obesity in both sexes, male cardiac hypertrophy, and altered behaviors suggestive of anxiety. These effects were all detected at exposure levels well below the NOAEL reported by the manufacturer. Another rat study of a metabolite of TBPH demonstrated maternal thyrotoxic and hepatotoxic effects, as well effects in fetal testes (Springer et al. Environ Health Perspect 2012;120:1711-19). In view of ongoing widespread FM 550 exposures to U.S. residents in their homes and offices, these preliminary findings warrant a larger-scale independent assessment of the toxicity of this mixture.
NTP Principles: not specified
Agents and Status
The following information relates to the specific agent and may include history from earlier or later nominations for this same agent.
Agent Name: Firemaster 550
Agent Name: Isopropylated Phenol Phosphate
Agent Name: 2-ethylhexyl-2,3,4,5-tetrabromobenzoate
Agent Name: Bis(2-ethylhexyl) tetrabromophthalate
Agent Name: Triphenyl Phosphate