Exposures, mechanisms, and impacts of endocrine-active flame retardants

Abstract

This review summarizes the endocrine and neurodevelopmental effects of two current-use additive flame retardants (FRs), tris (1,3-dichloro-isopropyl) phosphate (TDCPP) and Firemaster(®) 550 (FM 550), and the recently phased-out polybrominated diphenyl ethers (PBDEs), all of which were historically or are currently used in polyurethane foam applications. Use of these chemicals in consumer products has led to widespread exposure in indoor environments. PBDEs and their hydroxylated metabolites appear to primarily target the thyroid system, likely due to their structural similarity to endogenous thyroid hormones. In contrast, much less is known about the toxicity of TDCPP and FM 550. However, recent in vitro and in vivo studies suggest that both should be considered endocrine disruptors as studies have linked TDCPP exposure with changes in circulating hormone levels, and FM 550 exposure with changes in adipogenic and osteogenic pathways.

Figure 1

Structures, Physical Properties and Dust Concentrations of Selected Flame Retardants. Log K_ow values were taken from EPA’s modeling software EPISuite and from a recent review [85] The Production Volume estimates were taken from EPA’s Chemical Data Access Tool (CDAT), which contains the 2012 Chemical Data Reporting (CDR) information. All dust, serum, and urine measurements are reported from US cohorts.