Asbestos air sampling methodology 114 Liberty, Feb 2003

NYC 9/11 Public Portal Document

Dim» 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 forms must be transported to the laboratory immediately after sampling is completed.

Clearance Criteria

1. The following clearance levels have been established by the USEPA for clean up activities resulting from the collapse of the WTC.

Table 2: Clearance Criteria Parameter Clearance Level Note Asbestos in air 0.0009 flee PCMe Primary clearance level Lead in settled dust <25 pg/tf Primary clearance level Dioxin in settled dust <4ng/m^ Primary clearance level Fibrous glass in air <0.01 f/cc Secondary clearance level Crystalline silica in air Ipg/m^ Secondary clearance level PAHs in settled dust <0/3 mg/m^ Primary clearance level

Cleaning shall not be considered complete unless the primary clearance levels are achieved (see Table 2). The apartment will be re-cleaned and retested if the primary clearance levels are not achieved. These clearance levels may be re-evaluated and revised if determined necessary based on field conditions and analytical limitations. Secondary clearance levels shall be considered in determining the need for additional cleanup, however failure to meet the secondary clearance levels does not automatically trigger the re-cleaning. In the event re-cleaning is required, re-sampling shall be performed immediately upon completion of the cleaning.

Project Monitoring

1. The project monitor shall provide oversight of clean-up activities to ensure compliance with project specifications, tenants authorizations, and applicable rules and regulations. The project monitor shall be present on site during all cleaning activities. The project monitor shall coordinate all scheduling requirements for timely completion of the work (completion of work area preparation and cleaning activities within three (3) weeks. The project monitor shall maintain the inventory of valuable items in each_uiiit_as_provided by tenants. A copy of the contractor requirements is attached. For additional and specific tasks, refer to this attachment.

2. The project monitor shall provide daily monitoring of all work activities to insure compliance with the scope-of-work, the applicable rules and regulations, and the contracts. This includes but is not limited to the verification of worker certification status, the use of proper engineering controls and appropriate work practices. 5 of 6

NYC-WTC_000155436