Organophosphorus flame retardants in children’s car seats: Implications for vehicle air quality

¹ Environmental Health Science and Research Bureau, Health Canada, Canada K1A0K9, email address: jiping.zhu@hc-sc.gc.ca
² Environmental Health Science and Research Bureau, Health Canada, Canada K1A0K9, email address: dharani.das@hc-sc.gc.ca

Abstract

Flame retardants (FRs) are used in many consumer products for fire safety reasons. Their use in children’s car seats may result in children’s and vehicle occupants’ exposure to these compounds including inhalation exposure through poor vehicle air quality. We have tested several children’s car seats from local retailers for the presence of FRs. A number of organophosphorus flame retardants (OPFRs) were identified in the extracts (dichloromethane) of eight foam materials taken from the seats. They included several organophosphates (triethyl phosphate (TEP) (detected in all 8 samples) followed by tris(butoxyethyl) phosphate (2), triphenyl phosphate (1), di-(t-butylphenyl) phenyl phosphate (1) butyl diethyl phosphate (1) and tris(4-tert-butylphenyl) phosphate (1)) and organophosphonates (two isomers of 5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl methyl methylphosphonate (PMMMP) (detected in 5 of the 8 samples) followed by diethyl ethylphosphonate (1) and 4-methoxy-2-methylbutyl ethyl butylphosphonate (1)). TEP was the most frequently detected among these OPFRs. Due to its relatively high vapour pressure (0.39 mm Hg at 25 °C) among detected OPFRs, TEP is most likely to emit into vehicle interior air during product use, which could result in inhalation exposure for the children using the car seat and other passengers. We therefore have tested the emission rate of TEP in a micro-chamber at 40 °C for estimating potential exposure of vehicle occupants. The emission profile shows the concentrations of TEP in the chamber reached a maximum within the first few hours and then decreased over time. There was a lack of correlation between 24-hour average emission rate and concentrations of TEP in the product. The exact health risk to children and other vehicle occupants in this case requires further research to quantify.