NYC-WTC_000195194

NYC 9/11 Public Portal Document The study found that the observation of WTC dust Io an indicator that WTC contaminants may be present and that the amount of WTC dust correlates with the level of contamination. 5.3 Location of Units Based upon the visual observations of dust and the ranking of individual apartments for pre- cleaning analytical results, it was noted that the apartments facing the WTC site corresponded with a higher average level of contamination within the unit for lead, asbestos and MMVF. Specifically, the units facing Liberty Street (units with C and D designations) which were in the direct path of the WTC collapse generally showed the greatest degree of contamination. This indicates that buildings, or portions of buildings, that had significant amounts of dust deposited from the WTC site may have had a greater amount of contamination than buildings that did not have significant amounts of dust deposited The study found that the portions of the building with higher levele of deposited WTC dust had higher levels of contamination. 5.4 Comparison to Health-Based Benchmarks The pre-cleaning analytical results for all of the data sets listed above were also evaluated to determine if the concentration of contaminants in the dust were elevated above health-based benchmarks. For this evaluation, the health-based benchmarks presented in Table 1.0 were used for comparison to the pre-cleaning and post-cleaning sampling results. Based on pre-cleaning data, there were ten residential units and five commercial units that exceeded a health-based benchmark for either lead, dioxin, PAH, or some combination of the three compounds. Based on post-cleaning data, an additional three residential units and one common area exceeded a health- based benchmark for either asbestos, lead, MMVF, or alpha-quartz, or a combination of these compounds. Cumulatively, nineteen sites inside the building or 76 percent exceeded a health-based benchmark for one or more contaminants associated with the WTC collapse. This indicates that some contaminant concentrations exceeded health-based benchmarks. The study found that concentrations of some contaminants in the WTC dust were elevated above health-based benchmarks. 108 CITY_21MC100_011105338 NYC-WTC_000195304