(VCCEP) Tier 1 Pilot Submission for BENZENE - Tera

Table 5.11: Benzene Releases for All Industries Reporting TRI data for 2003
Benzene VCCEP Submission
March 2006
Type of Release Release Amount
(million
pounds/year)
34
Percent of Total Release
Total air emissions 6.26 93%
Surface water discharges 0.019 0.3%
Underground injections 0.36 5.3%
Releases to land 0.033 0.5%
Transfer to disposal 0.075 1.1%
Total 6.75 100%
5.10 Contribution of Chain-of-Commerce Sources and Releases to Personal Exposure
“The central principal of measuring human exposure is [to] measure where the people are”
(Wallace, 2001). This was the guiding principle of the EPA Total Exposure Assessment
Methodology (TEAM) Studies, which took place between the 1980’s and 1990’s.
The TEAM studies consistently showed that indoor benzene exposures were greater than
outdoor exposures (Wallace, 2001). They also concluded that “no effect on personal exposure
of living close to major fixed sources of benzene (oil refineries, storage tanks, chemical plants,
etc.) could be detected” in six cities where personal exposures to benzene were investigated
(Wallace, 1996). Rather, most benzene exposure was found to be caused by personal
activities, such as riding in a vehicle or smoking cigarettes (Wallace, 1996, 2001). For smokers,
Wallace concluded that 89% of personal benzene exposure was attributable to mainstream
cigarette smoke. Non-smoker’s exposure to benzene was found to be primarily attributable to
automobile exhaust or gasoline vapor emissions (e.g., vapor emissions during refueling or
indoor exposures occurring as a result of vapor intrusion from an attached garage; Wallace,
1996, 2001).
The TEAM studies have concluded that the “following are not important sources of exposure to
benzene on a nationwide basis” (Wallace, 1989a):
• Chemical plants;
• Petroleum refining operations;
• Oil storage tanks; and
• Drinking water.
The findings of Wallace regarding the contribution of community industrial sources on personal
exposures to benzene have also been observed by more recent studies conducted by Mickey
Leland National Urban Air Toxics Research Center (NUATRC) and other independent
researchers. In contrast to the findings of Wallace however, the recent literature indicates that
in-vehicle exposures and environmental tobacco smoke are not the primary sources of personal
benzene exposure. Rather the personal exposures are driven by in-home indoor air
concentrations and mainstream smoking. This is further discussed in Section 7.