(VCCEP) Tier 1 Pilot Submission for BENZENE - Tera

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influenced the indoor air benzene concentratons. Figure 7.2 shows a comparison of various descriptive statistics of the attached garage homes. Benzene VCCEP Submission March 2006 Figure 7.2 Comparison of Indoor Air Benzene Concentrations in Smoking and Non-Smoking Households with Attached Garages Benzene Concentration (ug/m3) 60.0 50.0 40.0 30.0 20.0 10.0 0.0 Smoking Household Non-smoking Household Homes With Attached Garage 113 Min Max Average Median As shown on Figure 7.2, the presence of a smoker in a home with an attached garage has little to no impact on the indoor air concentrations of benzene in the home. This indicates that the attached garage is a more significant source of benzene in the indoor air, than benzene from environmental tobacco smoke (ETS). The contribution to children’s benzene exposure is further discussed in Section 7.2.2.2. Accordingly, the high-end indoor air concentration used in this assessment was 11.5 µg/m 3 . 7.2.1.4 Indoor Air Trends Analysis Given the continued improvements in vehicle emission controls and the widespread use of reformulated gasoline, it is likely that indoor air concentrations of benzene will continue to decrease. In an effort to understand this likely trend, a factor was developed to normalize the “historical” measured indoor air data to current day conditions. This factor was derived using EPA’s MOBILE 6.2 model. MOBILE is an EPA emissions factor model for estimating pollution from on-road motor vehicles. The model accounts for the emission impacts of factors such as changes in vehicle emission standards, changes in vehicle populations and activity (i.e., fleet differences), and variation in local meteorological conditions, fuel properties and air quality programs. In deriving the normalization factor (NF), MOBILE 6.2 was used to estimate the change in benzene emission rates given the historical and current conditions of fleet and fuel properties. Fleet and fuel properties in Minnesota served as the basis for the normalization factor because the Adgate et al. (2004b) study (conducted in Minnesota in 1997) was the most recent and robust dataset that was available. The fleet and fuel properties in Minnesota in 1997 and that in 2003 were modeled to estimate the change in evaporative emission rates (i.e., hot-soak, diurnal, and resting). The change in emission rates was then used to estimate the emission
factor change attributable to benzene content decreases in gasoline and those attributable to fleet emission control improvements. A detailed description of the methods used to derive the NF is presented in Appendix A. The NF ranged from 1.07 to 1.24, depending on whether it was assumed that there were only cars in the garage, a mix of cars and small engine sources or small engines only. When the NF is applied to the measured air concentrations from Adgate et al. (2004b), the normalized concentrations ranged from 7% reduction in benzene concentrations for homes with small engines only in the garage to 18% reduction in homes with small engines and cars in the garage. Based on this analysis, it is believed that the indoor air concentrations used in this assessment are conservative (i.e. exposure enhancing) estimates of children’s exposure. Future residential indoor air studies will likely show that benzene air concentrations are lower than those used in this analysis. 7.2.1.5 Alaskan Indoor Air Studies Several attached garage studies that measured benzene levels in indoor air have been conducted in Alaska (Isbell et al., 1999, Schalapia and Morris, 1998, and Morris 2004). The benzene measurements from these studies are provided in Table 7.12. The indoor air concentrations of benzene measured in the Alaskan studies have been higher than those measured in the other attached garage studies (See Table 7.11). Also of note, Isbell et al. (1999) found that the reported concentrations were strongly correlated to the number of small engines stored in the garage and whether the home had a forced ventilation system or ventilated naturally via the building shell, windows and doors (Isbell, et al., 2005). Several factors are believed to be related to these higher observed values. The benzene content of conventional gasoline produced in the lower 48 states is roughly 1% - well below the regulatory (Complex Model) limit of 5%. Due to equipment and demand limitations on refining operations, gasoline produced in Alaska generally contains higher levels than in the lower 48 states, ranging from 2.2 – 4.5% in the three indoor air studies conducted. It should be noted that although the benzene content in Alaskan gasoline is higher than that in the lower 48 states, levels have recently been declining and have dropped approximately a percentage point from 2002 (3.2 – 3.6%) to 2005 (2.3 – 2.8%) (AAM 2002-2005). Another probable reason that the Alaskan indoor air levels are higher is that the homes and garages are believed to have better insulation and lower air exchange rates. Based on these data, children in Alaska may be exposed to higher indoor air levels of benzene than the remainder of the U.S. Benzene VCCEP Submission March 2006 114
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Voluntary Children’s Chemical Eva
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6.1.2 Types of Adverse Health Effec
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Glossary of Terms μg Microgram AA
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STEL Short-Term Exposure Limit TEAM
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enzene induced pancytopenias can pr
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A fertility study in female rats ex
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estimate is very conservative both
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2.0 BASIS FOR INCLUSION OF BENZENE
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2.5 Air Monitoring Data Several of
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Table 3.1: Proposed Benzene AEGL Va
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4.0 Regulatory Overview This sectio
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passenger vehicles operated at cold
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Benzene has been designated a hazar
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products had ceased” [46 Fed. Reg
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5.0 CHEMICAL OVERVIEW This section
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Table 5.3: Environmental Fate and T
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general, the production rate is abo
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gasoline. Aromatic hydrocarbons, su
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The EPA Office of Air Quality Plann
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Benzene VCCEP Submission March 2006
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Table 5.11: Benzene Releases for Al
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6.1.2.2 Chronic Toxicity Toxicity a
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6.1.2.2e Other Hematopoietic Malign
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that transient, high peak exposures
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absorption compared to inhalation,
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increased risk of disease. It shoul
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The National Cancer Institute (NCI)
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exposure. This was also supported b
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follow-up of this same cohort, Wong
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development of MDS)and/or AML. It i
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quantification of benzene air conce
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4.0, 95% CI = 1.8-9.3) but not ALL
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6.2 Benzene Toxicology—Animal Haz
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eakage and loss was comparable whet
Page 69 and 70: Benzene VCCEP Submission March 2006
Page 71 and 72: Table 6.2: In Vivo Genotoxicity of
Page 73 and 74: Table 6.2 Continued: In Vivo Genoto
Page 75 and 76: 6.2.2.3 Transplacental Genotoxicity
Page 77 and 78: induce solid tumors in animals in t
Page 79 and 80: mice in the 300-ppm group had bilat
Page 81 and 82: decreases in maternal weight gain,
Page 87 and 88: increased resorptions. The effects
Page 89 and 90: proposed that transplacental effect
Page 91 and 92: glycerol lysis time, and incidence
Page 93 and 94: 6.2.5.2 Chronic Toxicity Repeat-dos
Page 95 and 96: LOAELs for carcinogenic effects in
Page 97 and 98: the measurements of doses are suspe
Page 99 and 100: intracellular pathogen, Listeria mo
Page 101 and 102: 2. Evidence indicates that myelotox
Page 103 and 104: 7.0 Exposure Assessments This secti
Page 105 and 106: throughout childhood, see Table 7.1
Page 107 and 108: 7.2 Sources of Benzene Exposure Chi
Page 109 and 110: Table 7.3: Outdoor Ambient Air Benz
Page 111 and 112: Table 7.5: County-Wide 24-hour Ambi
Page 113 and 114: Age-specific benzene intakes are pr
Page 115 and 116: Table 7.9: Total ADDs for Exposure
Page 117 and 118: Table 7.10 (cont.) Study Location a
Page 119: Table 7.11: Summary of Benzene Meas
Page 123 and 124: where: ADD = average daily dose (mg
Page 125 and 126: Table 7.16: Total ADDS from In-Home
Page 127 and 128: Table 7.18: Summary of Age-Specific
Page 129 and 130: Table 7.20: Summary Statistics for
Page 135 and 136: In-Vehicle Exposures In-vehicle exp
Page 137 and 138: Table 7.30: Average of Mean In-Vehi
Page 139 and 140: e similar to those in other U.S. st
Page 141 and 142: vehicle); the total amount of time
Page 143 and 144: use of small non-road engine equipm
Page 145 and 146: Children may be exposed to benzene
Page 147 and 148: Table 7.36: Typical School Year Wee
Page 149 and 150: An addition of less than 1 µg/m 3
Page 151 and 152: In the mid-1990s, the American Petr
Page 153 and 154: Table 7.44: Dermal Benzene Absorpti
Page 155 and 156: Table 7.47: Product Names and Manuf
Page 157 and 158: Table 7.49: Summary of Age-Specific
Page 159 and 160: For children and non-smoking adults
Page 161 and 162: Benzene Exposure (mg/kg-day) Figure
Page 163 and 164: ackground pathways of exposure, inc
Page 165 and 166: 8.1.3 EPA Default Risk Assessment N
Page 167 and 168: 8.2.1 Potential for Increased Sensi
Page 169 and 170: These findings illustrate examples
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information associated with benzene
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species are more sensitive than oth
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8.2.3.1 Point of Departure for Non-
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Cancer risks were calculated using
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NONCANCER HAZARD QUOTIENT 1.00 0.09
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Table 8.1. Derivation of noncancer
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Table 8.3. Points of departure for
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Table 8.4. (cont.) Noncancer Hazard
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Table 8.5. Noncancer hazard quotien
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Table 8.6. Cancer risk estimates as
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Table 8.7. Indoor air comparison (i
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Table 8.9. Noncancer margins of saf
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Table 8.10. Noncancer margins of sa
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Table 8.11. Indoor air comparison (
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Table 8.13. (cont.) Notes: Cancer M
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the continental U.S. for each leuke
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in significant reductions in benzen
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Aksoy M (1977) Leukemia in workers
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Austin, C.C., Wang, D., Ecobichon,
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Buckley, J.D., Ribison, L.L., Swoti
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CONCAWE. 1996. Scientific basis for
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Ding, X-J, Li, Y., Ding, Y. el al.
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Forni, A. 1994. Comparison of chrom
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Goldwater LJ (1941) Disturbances in
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Hsieh, G.C., Parker, R.D., and Shar
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Jo, W.K. and Park, K.H. 1998. Expos
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Lange, A., Smolik, R., Zatonski, W.
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Lynge E, Andersen A, Nilsson R, Bar
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Meadows, A., Obringer, A. M. O., Ba
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Nedelcheva V, Gut I, Soucek P, Tich
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Picciani, D. 1979. Cytogenetic stud
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Ross D, Siegel D, Gibson NW, Pachec
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Sathiakumar, N., Delzell, E., Cole,
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Smith, M. T., Zhang, L. P., Wang, Y
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Thomas, K.W., Pellizzari, E.D., Cla
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United States Environmental Protect
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URS. 2002. Air Quality Trend in the
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Weisel, C.P. 2002. Assessing exposu
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Xing, S.G., Shi, X., Wu, Z.L., Chen
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(VCCEP) Tier 1 Pilot Submission for BENZENE - Tera

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