NYC-WTC_000195194

NYC 9/11 Public Portal Document

particulate material. The remaining sample was below the primary clearance criterion of 0.0009 S/cc. The results of the seven micro vacuum samples indicate that asbestos was present at concentrations lower than those observed before cleaning. The results of the wipe samples indicate that asbestos was present in all four samples at higher concentrations than those observed before cleaning.

Post P‘ Cleaning Samples (Test 48) - Three air samples and four wipe samples were collected for asbestos. The three air samples were analyzed using PCM, TEM AHERA, and PCMe. The PCM results indicate that two samples could not be analyzed due to overloading of particulate material and one sample was above the secondary numeric criterion of 0.01 ftcc. The TEM AHERA and PCMe analyses could not be analyzed due to overloading of particulate matter.

Asbestos was present in three of the four wipe samples at higher concentrations than those observed before cleaning, but similar to the Test 4A samples. One sample was recorded as below the detection limit; however, the detection limit was greater than normal due to the presence of particulate material.

Post P‘ Cleaning Samples (Test 4C) - Five air and seven micro vacuum samples were collected. Five air samples were analyzed using PCM, TEM AHERA, and PCMe. The PCM results indicate that all five samples were below the secondary numeric criterion of 0.01 f/cc The TEM AHERA results indicate that all five samples were below the secondary numeric criterion of 0.022 S/cc. The PCMe results indicate that all five samples were above the primary clearance criterion of 0.0009 S/cc. The results of the seven micro vacuum samples indicate that asbestos was present in concentrations above the detection level in four of the seven samples. However, post-cleanup sample concentrations were lower than those observed before cleaning and after Test 4A cleaning.

Post P‘ Cleaning Samples (T?st 4D) - Three air samples were collected and analyzed using PCM, TEM AHERA, and PCMe. The PCM results indicate that all three samples were below the detection limit and below the secondary numeric criterion of 0.01 f/cc. The TEM AHERA results indicate that all three samples were below the detection limit and below the secondary numeric criterion of 0.022 S/cc. The PCMe results indicate that all three samples were below the detection limit and below the primary clearance criterion of 0.0009 S/cc.

Dio?dn 8efore Cleaning Samples - Two air samples and three 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 0.001 ng/m’ for air and 4 ng/m" for settled dust.

Post P’ Cleaning Samples (Test 4A) - Four wipe samples were collected and analyzed for dioxin. The concentrations of dioxin were similar to the pre-cleaning samples. The TEQ concentration for each sample was below the primary clearance criterion of 4 ng/m^.

Post P‘ Cleaning Samples (Test 48) - Four post-cleaning wipe samples were collected

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