Chain of custody form for DEP environmental samples, 2001

NYC 9/11 Public Portal Document

Cleaning Method - This unit was cleaned using Test 2A: a Ridgid® shop vacuum and a Eureka® upright vacuum with a HEPA filter. No AFDs were used. All horizontal surfaces were wet- wiped. This cleaning method was used for each cleaning event.

Cleaning Results - This unit met the clearance listed in Table 1.0 for each compound after being cleaned twice.

Asbestos Before Cleaning Samples - Six micro vacuum and five wipe samples were collected for asbestos. These samples indicate that asbestos was present in the unit prior to cleaning. All six of the micro vacuum samples detected chrysotile above the detection limit. Two of the five wipe samples were below the detection limit, although one detected chrysotile. The remaining three samples were above the detection limit.

Post Cleaning Samples - Three air, six micro vacuum samples and five wipe samples were collected for asbestos. The samples were analyzed using PCM, TEM AHERA, and PCMe. The results for the PCM analysis indicate that two of the three samples were below the secondary numeric criterion of 0.01 ficc. The third slightly exceeded this value with a concentration of 0.02 f^cc. The TEM AHERA results indicate that all three samples were below the secondary numeric criterion of0.022 S/cc. The PCMe results indicate that two of the three air samples were below the primary clearance criterion of 0.0009 S/cc. The third sample detected chrysotile and was at the primary clearance criterion of 0.0009 S/cc.

The results of the six micro vacuum samples indicate that asbestos was present at levels lower than those observed before cleaning.

The results of the five wipe samples indicate that asbestos was present in all of the samples at concentrations similar to or lower than those observed before cleaning.

Dioxin Before Cleaning Samples - Four 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 Cleaning Samples - Four post-cleaning wipe samples were collected and analyzed for dioxin. The results indicate that there was dioxin present at concentrations lower than those observed in the pre-cleaning samples. In addition, the TEQ concentration for each sample was below the primary clearance criterion of 4 ng/m^. This indicates that the cleaning techniques were effective at reducing dioxin concentrations.

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

Post Cleaning Samples - Two air samples were collected after the first cleaning. Gypsum was not detected above the detection limit of 0.016 mg/m^ for these samples.

67

NYC-WTC_000145765