Biomarkers of Organophosphate and Polybrominated Diphenyl Ether (PBDE) Flame Retardants of American Workers and Associations with Inhalation and Dermal Exposures.

This study evaluated workers' exposures to flame retardants, including polybrominated diphenyl ethers (PBDEs), organophosphate esters (OPEs), and other brominated flame retardants (BFRs), in various industries. The study aimed to characterize OPE metabolite urinary concentrations and PBDE serum concentrations among workers from different industries, compare these concentrations between industries and the general population, and evaluate the likely route of exposure (dermal or inhalation). The results showed that workers from chemical manufacturing had significantly higher (p <0.05) urinary concentrations of OPE metabolites compared to other industries. Spray polyurethane foam workers had significantly higher (p <0.05) urinary concentrations of bis(1-chloro-2-propyl) phosphate (BCPP) compared to other industries. Electronic scrap workers had higher serum concentrations of certain PBDE congeners compared to the general population. Correlations were observed between hand wipe samples and air samples containing specific flame-retardant parent chemicals and urinary metabolite concentrations for some industries, suggesting both dermal absorption and inhalation as primary routes of exposure for OPEs. Overall, this study provides insights into occupational exposure to flame retardants in different industries and highlights the need for further research on emerging flame retardants and exposure reduction interventions.

Evaluating Exposure to VOCs and Naphthalene for Firefighters Wearing Different PPE Configurations through Measures in Air, Exhaled Breath, and Urine.

Firefighters are at an increased risk of cancer due to their occupational exposure to combustion byproducts, especially when those compounds penetrate the firefighter personal protective equipment (PPE) ensemble. This has led to questions about the impact of base layers (i.e., shorts vs. pants) under PPE ensembles. This study asked 23 firefighters to perform firefighting activities while wearing one of three different PPE ensembles with varying degrees of protection. Additionally, half of the firefighters unzipped their jackets after the scenario while the other half kept their jackets zipped for five additional minutes. Several volatile organic compound (VOC) and naphthalene air concentrations outside and inside of hoods, turnout jackets, and turnout pants were evaluated; biological (urinary and exhaled breath) samples were also collected. VOCs and naphthalene penetrated the three sampling areas (hoods, jackets, pants). Significant (p-value < 0.05) increases from pre- to post-fire for some metabolites of VOCs (e.g., benzene, toluene) and naphthalene were found. Firefighters wearing shorts and short sleeves absorbed higher amounts of certain compounds (p-value < 0.05), and the PPE designed with enhanced interface control features appeared to provide more protection from some compounds. These results suggest that firefighters can dermally absorb VOCs and naphthalene that penetrate the PPE ensemble.

Firefighters' urinary concentrations of VOC metabolites after controlled-residential and training fire responses.

INTRODUCTION: Firefighters are exposed to volatile organic compounds (VOCs) during structural fire responses and training fires, several of which (e.g., benzene, acrolein, styrene) are known or probable carcinogens. Exposure studies have found that firefighters can absorb chemicals like benzene even when self-contained breathing apparatus (SCBA) are worn, suggesting that dermal absorption contributes to potentially harmful exposures. However, few studies have characterized VOC metabolites in urine from firefighters. OBJECTIVES: We quantified VOC metabolites in firefighters' urine following live firefighting activity across two field studies. METHODS: In two separate controlled field studies, spot urine was collected before and 3 h after firefighters and firefighter students responded to simulated residential and training fires. Urine was also collected from instructors from the training fire study before the first and 3 h after the last training scenario for each day (instructors led three training scenarios per day). Samples were analyzed for metabolites of VOCs to which firefighters may be exposed. RESULTS: In the residential fire study, urinary metabolites of xylenes (2MHA), toluene (BzMA), and styrene (MADA) increased significantly (at 0.05 level) from pre- to post-fire. In the training fire study, MADA concentrations increased significantly from pre- to post-fire for both firefighter students and instructors. Urinary concentrations of benzene metabolites (MUCA and PhMA) increased significantly from pre- to post-fire for instructors, while metabolites of xylenes (3MHA+4MHA) and acrolein (3HPMA) increased significantly for firefighter students. The two highest MUCA concentrations measured post-shift from instructors exceeded the BEI of 500 µg/g creatinine. CONCLUSIONS: Some of the metabolites that were significantly elevated post-fire are known or probable human carcinogens (benzene, styrene, acrolein); thus, exposure to these compounds should be eliminated or reduced as much as possible through the hierarchy of controls. Given stringent use of SCBA, it appears that dermal exposure contributes in part to the levels measured here.

Characterizing exposure to benzene, toluene, and naphthalene in firefighters wearing different types of new or laundered PPE.

The fire service has become more aware of the potential for adverse health outcomes due to occupational exposure to hazardous combustion byproducts. Because of these concerns, personal protective equipment (PPE) manufacturers have developed new protection concepts like particulate-blocking hoods to reduce firefighters' exposures. Additionally, fire departments have implemented exposure reduction interventions like routine laundering of PPE after fire responses. This study utilized a fireground exposure simulator (FES) with 24 firefighters performing firefighting activities on three consecutive days wearing one of three PPE ensembles (stratified by hood design and treatment of PPE): 1) new knit hood, new turnout jacket and new turnout pants 2) new particulate-blocking hood, new turnout jacket and new turnout pants or 3) laundered particulate-blocking hood, laundered turnout jacket and laundered turnout pants. As firefighters performed the firefighting activities, personal air sampling on the outside and inside the turnout jacket was conducted to quantify exposures to volatile organic compounds (VOCs) and naphthalene. Pre- and immediately post-fire exhaled breath samples were collected to characterize the absorption of VOCs. Benzene, toluene, and naphthalene were found to diffuse through and/or around the turnout jacket, as inside jacket benzene concentrations were often near levels reported outside the turnout jacket (9.7-11.7% median benzene reduction from outside the jacket to inside the jacket). The PPE ensemble did not appear to affect the level of contamination found inside the jacket for the compounds evaluated here. Benzene concentrations in exhaled breath increased significantly from pre to post-fire for all three groups (p-values < 0.05). The difference of pre-to post-fire benzene exhaled breath concentrations were positively associated with inside jacket and outside jacket benzene concentrations, even though self-contained breathing apparatus (SCBA) were worn during each response. This suggests the firefighters can absorb these compounds via the dermal route.

Characterizing exposures to flame retardants, dioxins, and furans among firefighters responding to controlled residential fires.

Firefighters may encounter items containing flame retardants (FRs), including organophosphate flame retardants (OPFRs) and polybrominated diphenyl ethers (PBDEs), during structure fires. This study utilized biological monitoring to characterize FR exposures in 36 firefighters assigned to interior, exterior, and overhaul job assignments, before and after responding to controlled residential fire scenarios. Firefighters provided four urine samples (pre-fire and 3-h, 6-h, and 12-h post-fire) and two serum samples (pre-fire and approximately 23-h post-fire). Urine samples were analyzed for OPFR metabolites, while serum samples were analyzed for PBDEs, brominated and chlorinated furans, and chlorinated dioxins. Urinary concentrations of diphenyl phosphate (DPhP), a metabolite of triphenyl phosphate (TPhP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), a metabolite of tris(1,3-dichloro-2-propyl) phosphate (TDCPP), and bis(2-chloroethyl) phosphate (BCEtP), a metabolite of tris(2-chloroethyl) phosphate (TCEP), increased from pre-fire to 3-hr and 6-hr post-fire collection, but only the DPhP increase was statistically significant at a 0.05 level. The 3-hr and 6-hr post-fire concentrations of DPhP and BDCPP, as well as the pre-fire concentration of BDCPP, were statistically significantly higher than general population levels. BDCPP pre-fire concentrations were statistically significantly higher in firefighters who previously participated in a scenario (within the past 12 days) than those who were responding to their first scenario as part of the study. Similarly, firefighters previously assigned to interior job assignments had higher pre-fire concentrations of BDCPP than those previously assigned to exterior job assignments. Pre-fire serum concentrations of 2,3,4,7,8-pentachlorodibenzofuran (23478-PeCDF), a known human carcinogen, were also statistically significantly above the general population levels. Of the PBDEs quantified, only decabromodiphenyl ether (BDE-209) pre- and post-fire serum concentrations were statistically significantly higher than the general population. These results suggest firefighters absorbed certain FRs while responding to fire scenarios.

Firefighter hood contamination: Efficiency of laundering to remove PAHs and FRs.

Firefighters are occupationally exposed to products of combustion containing polycyclic aromatic hydrocarbons (PAHs) and flame retardants (FRs), potentially contributing to their increased risk for certain cancers. Personal protective equipment (PPE), including firefighter hoods, helps to reduce firefighters' exposure to toxic substances during fire responses by providing a layer of material on which contaminants deposit prior to reaching the firefighters skin. However, over time hoods that retain some contamination may actually contribute to firefighters' systemic dose. We investigated the effectiveness of laundering to reduce or remove contamination on the hoods, specifically PAHs and three classes of FRs: polybrominated diphenyl ethers (PBDEs), non-PBDE flame retardants (NPBFRs), and organophosphate flame retardants (OPFRs). Participants in the study were grouped into crews of 12 firefighters who worked in pairs by job assignment while responding to controlled fires in a single-family residential structure. For each pair of firefighters, one hood was laundered after every scenario and one was not. Bulk samples of the routinely laundered and unlaundered hoods from five pairs of firefighters were collected and analyzed. Residual levels of OPFRs, NPBFRs, and PAHs were lower in the routinely laundered hoods, with total levels of each class of chemicals being 56-81% lower, on average, than the unlaundered hoods. PBDEs, on average, were 43% higher in the laundered hoods, most likely from cross contamination. After this initial testing, four of the five unlaundered exposed hoods were subsequently laundered with other heavily exposed (unlaundered) and unexposed (new) hoods. Post-laundering evaluation of these hoods revealed increased levels of PBDEs, NPBFRs, and OPFRs in both previously exposed and unexposed hoods, indicating cross contamination. For PAHs, there was little evidence of cross contamination and the exposed hoods were significantly less contaminated after laundering (76% reduction; p = 0.011). Further research is needed to understand how residual contamination on hoods could contribute to firefighters' systemic exposures.