Socioeconomic Status and Exposure to Chemical Flame Retardants

Date of Award


Document Type

Honors Thesis


Environmental Studies

First Advisor

Gregory J. Howard




Background: Polybrominated Diphenyl Ethers (PBDE’s) have been phased out of production in the USA since 2005 due to concerns about their persistence, bioaccumulation and toxicity. Subsequent regulation of PBDE production by the US Environmental Protection Agency aimed to universally reduce exposure to these chemicals in the United States. Yet, at least one previous study has found that households of lower socioeconomic status are more prone to have a higher body burden of PBDE’s than households of higher socioeconomic status. Understanding the cause of this inequitable exposure among different households requires further research.

Objectives: My objective was to determine whether individuals who report lower household annual income are disproportionately exposed to chemical flame retardants which have been phased out for health and environmental concerns (particularly PBDE’s). Essentially this study aimed to determine if exposure to PBDE’s is an environmental equity issue.

Methods: We examined the association between reported household annual income (socioeconomic status) and the presence of chemical flame retardants in household furniture in two towns in Pennsylvania. Identification of the flame retardant in foam collected from household furniture served as a proxy for exposure within the home. Samples were analyzed by GC/MS at the Superfund Analytical Chemistry Core at Duke University. Socioeconomic status, the demographics of the household sampled, and basic information about the piece of furniture, including tags indicating compliance with California flame retardancy standards, were determined using a simple questionnaire. We then investigated whether human serum PBDE levels were higher in individuals who reported lower household annual income by analyzing the 2003-2004 National Health and Nutrition Examination Survey (NHANES).

Results: We determined that individuals who report low household annual income are more likely to own older furniture than those of higher socioeconomic status. However, there was a surprisingly small number of chemical flame retardant detections in the experimental study and only one sample that contained PBDE’s (which was owned by a high income individual). As a result, this study does not support the hypothesis that individuals of low socioeconomic status are disproportionately exposed to chemical flame-retardants that have been phased out (notably PBDE’s) in their personal environments. In fact, the small number of flame retardant detects suggests that TB 117 may not be a “de facto national standard” as suggested in previous research. Also, since the frequency of detections increases in the last 10 years (newer furniture) this study suggests that although exposure to PBDE’s may have been a result of owning old furniture, general exposure to all flame retardants, at least in Pennsylvania, is more likely following purchase of new furniture.

Since the experimental study did not adequately address disproportionate exposure to PBDE’s, the 2003-2004 NHANES dataset was also analyzed. Analysis of the 2003-2004 NHANES dataset suggests that participants that report a household annual income below the national median ($54,999) are 14.5% more likely to have high concentrations of BDE-99 congener.

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