Systemic Exposure to PAHs and Benzene in Firefighters Suppressing Controlled Structure Fires

Abstract

Turnout gear provides protection against dermal exposure to contaminants during firefighting; however, the level of protection is unknown. We explored the dermal contribution to the systemic dose of polycyclic aromatic hydrocarbons (PAHs) and other aromatic hydrocarbons in firefighters during suppression and overhaul of controlled structure burns. The study was organized into two rounds, three controlled burns per round, and five firefighters per burn. The firefighters wore new or laundered turnout gear tested before each burn to ensure lack of PAH contamination. To ensure that any increase in systemic PAH levels after the burn was the result of dermal rather than inhalation exposure, the firefighters did not remove their self-contained breathing apparatus until overhaul was completed and they were >30 m upwind from the burn structure. Specimens were collected before and at intervals after the burn for biomarker analysis. Urine was analyzed for phenanthrene equivalents using enzyme-linked immunosorbent assay and a benzene metabolite (s-phenylmercapturic acid) using liquid chromatography/tandem mass spectrometry; both were adjusted by creatinine. Exhaled breath collected on thermal desorption tubes was analyzed for PAHs and other aromatic hydrocarbons using gas chromatography/mass spectrometry. We collected personal air samples during the burn and skin wipe samples (corn oil medium) on several body sites before and after the burn. The air and wipe samples were analyzed for PAHs using a liquid chromatography with photodiode array detection. We explored possible changes in external exposures or biomarkers over time and the relationships between these variables using non-parametric sign tests and Spearman tests, respectively. We found significantly elevated (P < 0.05) post-exposure breath concentrations of benzene compared with pre-exposure concentrations for both rounds. We also found significantly elevated post-exposure levels of PAHs on the neck compared with pre-exposure levels for round 1. We found statistically significant positive correlations between external exposures (i.e. personal air concentrations of PAHs) and biomarkers (i.e. change in urinary PAH metabolite levels in round 1 and change in breath concentrations of benzene in round 2). The results suggest that firefighters wearing full protective ensembles absorbed combustion products into their bodies. The PAHs most likely entered firefighters’ bodies through their skin, with the neck being the primary site of exposure and absorption due to the lower level of dermal protection afforded by hoods. Aromatic hydrocarbons could have been absorbed dermally during firefighting or inhaled during the doffing of gear that was off-gassing contaminants.

Changes in ozone and precursors during two aged wildfire smoke events in the Colorado Front Range in summer 2015

“…It is well known that wildfires produce carcinogenic aromatic hydrocarbons including benzene (Fent et al, 2014). During the smoke-impacted periods, we observed significantly enhanced benzene throughout the day with an average increase of 0.117 ppbv and a percentage increase of 67 %.…”

“…These enhancements followed the pattern of CO and ethyne; there were consistent increases throughout the day and the diurnal cycle retained its shape. Wildfires also produce toluene (Fent et al, 2014); however, it has a substantially shorter lifetime (< 2 days) than benzene (∼ 12 days). Toluene showed no significant changes in its mean mixing ratio, diurnal cycle, or range of values measured at BAO during the smoke-impacted periods.…”

Risk of cancer among firefighters in California, 1988–2007

“…During overhaul, firefighters can be exposed to combustion products through disassembling walls or removing furniture [Bates, 2007]. Furthermore, even when SCBAs are worn, firefighters can absorb combustion products through the unprotected skin on their neck [Fent et al, 2014]. Several combustion products are classified by the International Agency for Research on Cancer (IARC) as carcinogenic to humans (Group 1), probably carcinogenic to humans (Group 2A) or possibly carcinogenic to humans (Group 2B).…”

Assessment of Ambient Exposures Firefighters Encounter While at the Fire Station

“…There are many studies in the scientific literature that involve an assessment of the adverse exposures firefighters encounter; however, most of the studies focus on exposures experienced while in the field, [11] or at large, one-time events, such as the 9/11 World Trade Center response, [30] or rely on retrospective administrative data to assess risk. [4, 31]…”

“…[11, 12] Firefighters spend large portions of their shift waiting for calls in a station, [13] during which they can be exposed to diesel exhaust from idling trucks (which is a known carcinogen) [14-16] and off-gassing from contaminated post-fire gear (which may be contaminated with a variety of known and/or possible carcinogens). [17] Few studies have examined the effect of station-level exposures on firefighter health, and those that did are several decades old, [16] assessed exposures using only qualitative methods, [18, 19], dust samples [20] or used only fire-truck run data and building design characteristics to assess exposure.…”