37 MURRAY STREET Block: 133 Lot: 7504 BIN: 1001434

NYC 9/11 Public Portal Document FEB. 8.2002 444?PM J.C. BRODERICK & ASS Na.44? P.2

J.C. Broderick & Associates JCB Environmental Engineers, Consultants & Contractors February 7, 2002

Mr.Bob Dagger USAA PC Box 165 Nesconset,New York 11767

Re: Aggressive Asbestos Air Quality Sampling Report Letter Utilizing Transmisslun Electron Microscopy(TEM)Method of.Analysis at 37 Murray Street Apartment5A New York,New York Sampling Dater February 4,2002

JCB#: 02-2564

Dear Mr. Dagger:

J.C. Broderick & Associates, Inc.(JCB)was retained to perform aggressive asbestos in air sampling and analysis atthe abovereferenced site subsequentto detailed cleaning activities performed byBranch Services. The air sampling was performed by a JCB Now York State certified air samplingtechnician. Samples were collected, chain ofcustody forms prepared,and delivered to an Independent SLAP certified laboratory for the presence of asbestos fibers by Transmission Electron Microscopy(TEM).

Aggressive air sampling is a method ofair sampling in which the person collecting the air sample creates activity by the use of mechanical equipment during the sampling period to stir up settled dust to simulate activity in that arm ofthe building. Pro-sampling agitation is conducted before the sampling is performed with the use ofan electric powered forced air blower(leafblower). The air blower is theca directed against the furnishings, office equipment, walls,ceilings, floors, ledges and other surfaces. This is conducted for an extended period oftime(at least five(5)minutes per 1,000 square feet offloor space).

Subsequenttothe pre agitation 20inchfans are placed throughoutthe testspace(clean room, The -sampling

fans will be operated on slow speed and are pointed towards the ceiling( at least one fan per 10,000 cubic feet of room space). The air sampling pumps are then turned on. When the air sampling is completed the sampling pumps are turned off,samples removed and the fans are then turned off. Aggressive air sampling is considered the most representative of "worst case scenarios".

The TEM analysis involves collecting airborne contaminates across the face of a polycarbonate or mixed cellulose ester filter, Again, air is drawn across prescreened filters by the use of portable large volume vacuum pumps. Priorto analyzing,the filter media is collapsed using an acetone vaportechnique and then plasma etched. Then fiber structures are counted and analyzed using electron diffraction patterns and, in some cases,energy dispersive X-rays. Under this methodology,allfibers with a aspectratio greaterthan 5:1 and a length ofat least 0.5 micrometers are counted.. TEM analysis can positively identify these fibers as asbestos or non-asbestos. Section 90, The United States EnvironmentalProtection Agency(US EPA),as indicated in 40 CFTCPant763

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