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Fate and Transport of TCPP in Indoor Environments
Citation:
Liu, X. Fate and Transport of TCPP in Indoor Environments. 2020 Polyurethanes Technical Conference, Texas, North Carolina, October 05 - 07, 2020.
Impact/Purpose:
Spray polyurethane foam (SPF) has been used in residential, commercial, and public buildings as a versatile and effective insulation and sealant material. Organophosphorus flame retardant, tris(1-chloro-2-propyl) phosphate (TCPP, CAS# 13674-84-5), is one of the predominate flame retardants in SPF. To address the public concerns about chemical emissions from SPF, research has been conducted to investigate TCPP’s emission from building materials and determine emission controlling mechanisms and key emission parameters. The results help to fill the data gaps and reduce the uncertainty for interpreting the exposure data and for risk assessment. It supports EPA Office of Pollution Prevention and Toxics (OPPT) action plan chemicals for chemical assessments under the Toxic Substances Control Act.
Description:
Organophosphorus flame retardant, tris(1-chloro-2-propyl) phosphate (TCPP, CAS# 13674-84-5), is one of the predominate flame retardants in polyurethane foam products such as spray polyurethane foam insulation. Due to its relatively low volatility, TCPP has slow emissions but long-term effects in indoor environments. It can leach or diffuse out of the products and be released to the surrounding air and accumulate in indoor dust, leading to human exposure with potential acute and chronic adverse health effects. Understanding the fate and transport mechanisms of TCPP between the sources and the residential environment (air, dust, and interior surfaces) is important to enlighten risk assessment and policy decisions to protect human health. This presentation summarizes the work conducted at EPA’s Center for Environmental Measurement & Modeling in the last few years on the fate and transport mechanism study of TCPP in the indoor environment. Our research developed methods for the investigation of TCPP (1) sorption on building materials and consumer products, (2) emission controlling mechanisms and key emission parameters, (3) temperature influence on emissions, and (4) migration from sources to settled dust, including direct contact and sorption. The data collected through chamber testing experiments included emission rates, sorption rates, material/air partition coefficients, solid-phase diffusion coefficients, sorption rate constants, and concentrations in the sources. These data support the development of mass transfer models to predict the TCPP emissions and transport in indoor environments. The experimental data could be used as the basic model input for the development of exposure models. The research could help to fill the data gaps and reduce the uncertainty for interpreting the exposure data and for risk assessment. These developed methods can be extended for the further indoor air study of the migration pathways of other semi volatile organic compounds (SVOCs).