Fields and Forests in Flames: Lead and Mercury Emissions from Wildfire Pyrogenic Activity

upper percentiles in an exposure distribution (Chatterjee et al. 2008). The 90th percentile NHANES dietary values used by the FDA (2010) therefore cannot be characterized as biased toward safety. The National Toxicology Program (2005) and the California Environmental Protection Agency Office of Environmental Health Hazard Assessment (2005) have determined that there is sufficient evidence to consider naphthalene a carcinogen. The FDA's reliance on an outdated determination by the U.S. EPA (1998) does not constitute a conservative assessment of the health risks associated with exposures to naphthalene. Dickey offers the example of the cancer potency factor for benzo(a)pyrene (BaP) as specifically demonstrating a " bias toward safety " based on his assertion that it reflects the " 95% upper confidence limit of the dose–response curve. " This characterization does not match the description of the cancer potency factor on the Integrated Risk Information System (IRIS) website (U.S. EPA 1994). In fact, the cancer potency factor was based on the " geometric mean of four slope factors obtained by differing modeling procedures " (U.S. EPA 1994). Dickey further asserts that the cancer potency factor " could be as low as zero, " which implies no cancer risk and therefore contradicts the designation of BaP as a carcinogen by multiple authorita tive bodies Last, Dickey cites estimates of annual BaP dietary intake, which he attributes to natural occurrence, as a rationale for not considering the lower acceptable exposure levels we proposed in our commentary (Rotkin-Ellman et al. 2012). Unfortunately this logic is severely flawed and does not comport with the FDA's charge to protect public health. For an adult, with values based on standard risk assessment methods, the range of total dietary intake Dickey describes (0.16–3.3 µg/person/day) corresponds to a lifetime cancer risk ranging from 1.7 × 10 –5 to 3.4 × 10 –4 —the upper value exceeding what Dickey cites as an acceptable risk range of 1 × 10 –4 to 1 × 10 –6. An appropriate FDA response to this finding would be to investigate sources of dietary exposure to PAHs and enact policies to reduce unsafe exposures. This is what the European Union has done in setting standards for BaP in foods of concern (oils and fats, smoked meats, smoked fish, fish, crustaceans, mollusks, baby food, and infant formula) (European Food Safety Authority 2008). To argue that the presence of existing (and potentially unsafe) exposures precludes a thorough assessment of …