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3.0 Human Health Evaluation <br />Based on both regulatory requirements that are intended to protect public health (permit & <br />NESHAP) and in comparison with emission rates measured at other cement kilns, the Lyons <br />Plant emissions are low using either FF or TDF. In fact, a comparison between emissions test <br />data from the Lyons Plant and other cement kilns with both similar data as well as quantitative <br />risk assessment information is a simple way to illustrate how low the Lyons Plant emissions <br />are. One way to do this is to focus on emission rates for the small sub-set of chemicals that <br />typically are responsible for the majority of potential health risk estimates from cement kiln <br />emissions. <br />Comprehensive multi-pathway risk assessments previously conducted using source testing <br />data from three cement kilns located in California fired with either FF or TDF have estimated <br />potential cancer risks to range from one to nine in a million for either fuel sources~s. Potential <br />non-cancer chronic and acute risks were also negligible. These risk levels are considered <br />acceptable by EPA. <br />Table 9 is a brief summary of the top six risk drivers using data from three cement kiln emission <br />tests for which comprehensive human health risk assessments have been performed. The <br />focus of this table is hypothetical cancer risks because cancer risk estimates typically are the <br />most conservative and generally dominate environmental human health risk assessments. <br />This table summarizes the chemical risk drivers, emission rates, risk estimates by chemical <br />and percentage of the total risk for these plants. The Lyons Plant emission rates have been <br />added for comparison. <br />This table indicates that the risks for all four plants are driven by one or more members of a <br />suite of six chemicals; hexavalent chromium, formaldehyde, benzene, dioxins/furans, <br />carcinogenic PAHs, and PCBs. For the three other plants with comprehensive risk <br />assessments, the cancer risks vary within a relatively narrow range from less than one million <br />in a million to nine in a million for these risk driver chemicals, which is in the de minimis, or <br />negligible risk range. In addition, the estimated health risks are similar for FF and TDF within a <br />given plant. Although the pattern of the six risk drivers varies tremendously by plant and <br />sometimes between FF and TDF, the six risk driver chemicals generally account for 80-90% or <br />more of the overall risks. <br />Emission rates for these human health risk driver chemicals were generally low for the Lyons <br />Plant, compared to the plants in California. Berizene emission rates were extremely low for <br />TDF and barely detectable for FF. Total chromium was higher at the Lyons Plant for TDF than <br />observed at the other plants but chromium risks were extremely low at those plants as well, so <br />potential health risks for chromium emission rates at the Lyons Plant for either FF or TDF <br />would still be negligible. Conversely, dioxins were lower with FF at the Lyons plant and not <br />detected with TDF. Formaldehyde emission rates at the Lyons plant were low for both FF and <br />TDF. Emission rates for PCBs were non-detectable for the Lyons Plant for both FF and TDF. <br />Carcinogenic PAHs emission rates were so low that they would not make any quantitative <br />contribution to the risk estimate. <br />12 <br />