Air monitoring specs, 125 Cedar and 114 Liberty, August 2002

NYC 9/11 Public Portal Document

Asbestos Air Fiber Samples All samples collected will be analyzed by the NIOSH 7400 Method, Counting rule “A.” The remaining portion of the filter will be analyzed by AHERA Method which counts fibers >0.5 pm in length. The laboratory must also record fibers >5p m in length to determine the PCMe value. The PCMe Value is determined by counting all fibers >5pm with 3:1 aspect ratio by TEM.

The primary clearance level established by the US EPA is 0.0009 flbers/cc (PCME measured by TEM) for each sample. This clean-up criterion may be reevaluated and revised, if determined necessary based on field conditions and analytical limitations.

Total Metals and Mercury Wipe Samples Analysis of Total Metals (23 Target Metals) must be done utilizing the EPA Method SW-846 601OB. Mercury wipes must be analyzed in accordance with EPA Method SW-846 7471A. The clearance criteria for all the Target Metals in Wipe Samples except Lead is presently under review by the EPA. The EPA primary clearance level for Lead in Settled Dust is <25pg/ft2.

Dioxin Wipe Samples Analysis of Dioxin Wipe samples must be done utilizing EPA Method SW-846 8290. The criteria as established by the EPA for primary clearance is 4 ngms/m.^

Clean up will not be considered complete unless all primary clearance levels are achieved.

Secondary clearance levels are have been established by the US EPA for the following analytes but will not trigger additional cleaning if these levels are met: • Fiberglass in Air <0.01f/cc • Crystalline Silica in Air 0.5pg/m^ • PAHs in Settled Dust <0.3mg/m2 • Mercury in Wipes 1- 2mg/m2

A final report shall be submitted to the DEP within 1 week of the project completion. The report shall clearly identify the work performed in each unit and shall include all laboratory reports, chain-of-custody forms, field notes, copies of employee credentials (i.e. certificates), tenant and owner authorizations, etc.

8 of 8

NYC-WTC_000163368