DEP response letter regarding cleanup scope, Apr 2003

NYC 9/11 Public Portal Document

Asbestos Air Monitoring during cleanup activities. I . At a ruinituu►u, live (5) TLM samples shall be collected per day work area, the clean room of the 2. Samples shall be collected at isolation barriers outside the worker/waste decontamination facility, and outside of the building.

with Title 15, Chapter t of the 3. Sample collection during clean up activities shall be in accordance Rules of the City of New York (RCNY) and AHERA regarding documentation, sample locations, rate of flow, and required volumes to achieve the necessary analytical sensitivity. from obstruction. 4. Sampling equipment shall be placed at representative locations and away Sampling cassette must be placed on a tripod and not taped to existing surfaces. All air sampling equipment shall be pre- and post- calibrated to insure accurate air sampling volumes. free of dust 5. The Air Sampling Technician shall perform clearance air sampling after the areas are accumulations as determined by the Project Monitor. All surfaces must be completely dry prior to the start of sampling. Clearance air sampling shall be performed at each apartment. Five samples shall be collected in each apartment and two samples shall be collected in each common space. The elevator shaft and first floor commercial spaces shall be cleared separately. Clearance air monitoring shall be performed after the completion of all clean up activities at the work site. Clearance air sampling shall be aggressive and performed in accordance with Title 15, Chapter 1 of the RCNY Section 1-43 (a)-(d).

6. Clearance air samples shall be collected in accordance with the procedures specified in the NIOSH 7400 Method The flow rate for collection of air samples shall be at least 10 liters per minute and no more than 15 liters per minute. Air sampling cassettes must be monitored to ensure the filters do not develop dark spots that would indicate clogging. The minimum sampling volume is 3600 liters. If clogging develops, the cassette must be changed.

7. All clearance air samples and completed chain of custody fonts must be transported to the laboratory immediately after sampling is completed

Clearance Criteria

The following clearance levels have been established by the USEPA for clean up activities resulting from the collapse of the W"l'C.

/'aruineter clearance Level Note--- - Asbestos iii air 0.0009 1/cc PCMe Primary clearance level --- Lead in settled dust <25 µg/1t 2 Primary clearance level -- -- Dioxin in settled dust <4 ng%m Primary clearance level Fibrous glass in air <0.01 t/cc Secondary clearance level ------ -- -----...._----- Crystalline silica in air 0.511 , nth Secondary clearance level PAL-Is in settled dust <0.3 tng/n2 Secondary clearance level Mercury between I and 2 mg;/nn Secondary clearance level

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NYC-WTC 000107182