NYC 9/11 Public Portal Document
Post P* deeming Semiples - Two air samples, three micro vacuum samples and four wipe
samples were coUected after the first cleaning. The two air samples, aU three micro
vacuum samples, and three of the four wipe samples were below the detection Umit. The
fourth wipe sample was above detection limit but below the primary clearance criterion.
The results fi’om the first cleaning indicate that the cleaning technique was effective in
removing the elevated concentrations of lead observed prior to the first cleaning. Because
the primary clearance criterion for lead was met after the first cleaning, no additional
samples were coUected for analysis of lead.
Alpha-Quartz
Before Cleaning Samplesair samples were not collected.
Post P‘ Cleaning Samples - Two air samples were collected after the first cleaning. AU of
the samples were below the detection limit. This indicates that the cleaning method used
was able to reduce the pre-cleaning concentration of alpha-quartz. Because aU of the
samples were below the detection limit after the first cleaning, no additional samples were
coUected for analysis of alpha-quartz.
Calcite
Before deeming Samples - Pre-cleaning air samples were not coUected.
Post P‘ Cleaning Samples - Two air samples were coUected after the first cleaning. AU of
the samples were below the detection limit. Because all of the samples were below the
detection limit after the first cleaning, no additional samples were coUected for analysis of
calcite.
Cristobalite
Before deeming Samples - Pre-cleaning air samples were not coUected.
Post P‘ Cleaning Samples - Two air samples were collected after the first cleaning. All of
the samples were below the detection limit. Because aU of the samples were below the
detection limits after the first cleaning, no additional samples were coUected for analysis of
cristobalite.
Tridymite
Before deeming Samples - Pre-cleaning air samples were not coUected.
Post f* Cleaning Samples - Two air samples were collected after the first cleaning. AU of
the samples were below the detection limit. Because all of the samples were below the
detection limits after the first cleaning, no additional samples were coUected for analysis of
tridymite.
MMVF
Before deeming Samples - Four pre-cleaning wipe samples were collected. One of the
four samples was below the detection limit; MMVF was detected in the other three
samples.
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NYC-WTC_000145738
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