NYC-WTC_000195194

NYC 9/11 Public Portal Document

The results for two of the three micro vacuum samples indicate that asbestos was present at levels similar to those observed before cleaning. The third micro vacuum sample was reported as being below the detection limit.

The results for the five wipe samples indicate that two of the five samples were below the detection limit, although one of these samples had chrysotile detected. The remaining three samples had chrysotile detected at concentrations above the detection limit. Unlike the micro vacuum samples, the results of the wipe samples collected after the first cleaning were lower than the pre-cleaning concentrations. This indicates that the cleaning techniques used were able to reduce the concentrations of asbestos in settled dust.

Post 2^ Cleaning - Five asbestos air samples were collected after the second cleaning. The samples were analyzed for PCM, TEM AHERA, and PCMe. The PCM, TEM AHERA, and PCMe results could not be obtained due to the filters being overloaded with particulate material. Due to inconclusive PCMe results, a third cleaning was conducted.

Post 3^ Cleaning - Four asbestos air samples were collected after the third cleaning. The samples were analyzed for PCM, TEM AHERA, and PCMe. The PCM results indicate that one sample was below the detection limit and the other three were at the detection limit. All PCM results were below the secondary numeric criterion of 0.01 ftcc. The TEM AHERA results had chrysotile detected above the detection limit; however, all four results were below the secondary numeric criterion of 0.022 S/cc. The PCMe results indicate that two of the samples which were collected under a modified-aggressive sampling methodology, were below or at the detection limit. The remaining two samples, collected under an aggressive sampling methodology, were slightly above the primary clearance criterion of 0.0009 S/cc with results of 0.0015 S/cc and 0.0016 S/cc. The results obtained from the samples collected with the modified-aggressive sampling were used as evidence of meeting the primary clearance criterion.

Dioxin Before Cleaning Samples - Three pre-cleaning wipe samples were collected and analyzed for dioxin. The results indicate that dioxin was present; however, the TEQ concentration for each sample was below the primary clearance criterion of 4 ng/m^.

Post P' Cleaning Samples - Four post-cleaning wipe samples were collected and analyzed for dioxin. The results indicate that the TEQ concentration for each sample was below the primary clearance criterion of 4 ng/m^. Since dioxin was below the detection limit for all of the samples collected, there were no additional dioxin samples collected.

Gypsum Before Cleaning Samples - Pre-cleaning air samples were not collected.

Post P' Cleaning Samples - Two air samples were collected after the first cleaning. Gypsum was not detected in any sample.

Lead Before Cleaning Samples - Three micro vacuum samples and three wipe samples were

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