NYC 9/11 Public Portal Document
cleaning. Gypsum was not detected above the detection limit of 0.008 mg/m^ in the air
sample.
Lead (HVAC)
Before Cleaning Samples - One wipe sample was collected from the HVAC system.
Lead was detected above the primary clearance criterion of 25 pg/ft^ at 1310 pg/ft^.
Post P‘ Cleaning Samples, HVAC System - Two air samples and two wipe samples were
collected after the first cleaning. The two air samples were below the detection level and
primary clearance criterion of 1.0 pg/m’. Lead concentrations exceeded the primary
clearance criterion at 136 pg/ft^ and 183 pg/ft^. The post-cleaning lead exceedances were
attributed to the composition of the HVAC construction material.
Post deaning Samples (Test 4A) - Five air samples were collected. All were below
the detection level.
Alpha-Quartz (HVAC)
Before Cleaning Samples - Pre-cleaning air samples were not collected.
Post Cleaning Samples, HVAC System - One air sample was collected after the first
cleaning. The air sample was below the detection limit.
Calcite (HVAC)
Before Cleaning Samples - Pre-cleaning air samples were not collected.
Post f* deeming Samples, HVAC System - One air sample was collected. The air sample
was below the detection limit.
Cristobalite fufi<AC)
Before deeming Samples - Pre-cleaning air samples were not collected.
Post P‘ Cleaning Samples, HVAC System - One air sample was collected after the first
cleaning. The air sample was below the detection limit.
Tridymite (HVAC)
Before Cleaning Samples - Pre-cleaning air samples were not collected.
Post deaning Samples, HVAC System - One air sample was collected. The air sample
was below the detection limit.
MMVF (HVAC)
Before Cleaning Samples - One sample was collected. The wipe sample had an MMVF
concentration of 11732.44 S/cm^.
Post P‘ deaning Samples, HVAC System - Three air samples and two wipe samples were
collected. All of the air and wipe sample results indicate that MMVF concentrations were
below the detection limit and that the air samples were below the primary clearance
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NYC-WTC_000145789
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