NYC 9/11 Public Portal Document
Lead
Before Cleaning Samples - Seven micro vacuum samples and three wipe samples were
coUected. Lead was detected in one of the seven micro vacuum samples at concentrations
below the comparison value of 25 pg/ft^. All three wipe samples had detectable
concentrations of lead, two of which were above the primary clearance criterion of 25
Post P‘ deeming Scanpies - Two air samples, seven micro vacuum samples and four wipe
samples were collected after the first cleaning. The two air samples were below the
primary clearance criterion of 1.0 pg/m’. All seven micro vacuum samples were below the
comparison value. Two of the four wipe samples exceeded the primary clearance
criterion, therefore, additional cleaning was necessary.
Post 2nei deeming Scanpling - Three wipe samples were collected following the second
cleaning. The results of all three samples were below the primary clearance criterion. In
two of the samples, lead was not detected. The sampling results following the second
cleaning indicate that the primary clearance criterion was met.
Alpha-Quartz
Before Cleaning Samples — Pre-cleaning air samples were not collected.
Post P* deeming Semtples - Two air samples were collected after the first cleaning. All of
the samples were below the detection limit.
Calcite
Before deeming Samples - Pre-cleaning air samples were not collected.
Post J" deeming Samples - Two air samples were collected after the first cleaning. All of
the samples were below the detection limit.
Cristobalite
Before deeming Samples - Pre-cleaning air samples were not collected.
Post P‘ Cleaning Seanples - Two air samples were collected after the first cleaning. AU of
the samples were below the detection limit.
Tridymite
Before deeming Samples - Pre-cleaning air samples were not collected.
Post P* Cleaning Samples - Two air samples were collected after the first cleaning. All of
the samples were below the detection limit.
MMVF
Before deeming Samples - Three pre-cleaning wipe samples were collected. MMVF was
detected in all three of the samples.
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NYC-WTC_000145770
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