Air quality test reports cover letter, Jan 2002

NYC 9/11 Public Portal Document

0'3I28!2 1 10:14 5315803195 0-4VIROSCIEt;tcC4SLTAt4 PAGE 03

American Stock Exchange, 28 Sep ember 2001

centimeters) to produce the asbestos air concentration. The NIOSH 7400 or 7402 methods used by OSHA to evaluate worker exposure results in values of fibers per cubic centimeter. Fibers greater than 5 micrometers in length and greater than 0.25 micrometers it,, diameter are. counted. Structures counted in AHERA include the fibers in the NIOSH OSHA approach and inch des much smaller. structures. So the A.HERA air concentration presented rat the attached tables more protective than the NIOSH OSHA are

approach

Samples that met the U.S. EPA MMRA clearance criteria of 70 structures/square millimeter are considered acceptable and are considered safe for reoccupancy.

The 9s' floor has tluee samples (Room, 909. Cubical 49, and Cassaleggi room) that exceed the U.S. EPA A3x'ERA. clearance criteria of 70 atructures/square millimeter and one that approaches the a

clearance criteria ( Cubical 52). Cubical 39 has a value of 37.88. These results are less than the OSHA PEL of 0.1 fibers per cubic centimeter.

We believe the asbestos in the air in these areas is due to the catastrophe and we do not believe that the asbestos was from the 22 Thames 1uilding because of the residue from the explosions and collapse was found in significant quantities on this floor and because the other results in 22 Thames and 86 Trairy Place are so low. Other floors such as the 5"' floor also had significant quantities of the residue from the explosions and collapse. On September 23, 2001, we recommend that the floors in 22 Thames, that had not been tested be tested. This sampling was cornpieted on September 24"' 2001.

Outdoors samples were collected att the 4`" floor, and the B" floor. These samples were all less than detectable limits. These outdoor samples may be compared with the U.S. EPA collected asbestos air monitoring locations Lower Manhattan that are presented on 1wwww.vpa.goviepahotnelcatarnapd2.hrm.

Asbestos bulk samples were collected on September 20''' and September 24"'. Dust samples were collected from exterior window ledges and different sites where material was available inside the building. All samples collected are nct considered asbestos contai;:irg material since they contain less than ,site percent asbestos. The Asbestos bulk sample results are presented in the attached tables.

The asbestos clean up must be conducted by New York State and U.S. EPA certified asbestos abatement contractors and workers. The general cleaning proiccct once gross debris has been removed is to HEPA vacuum, followed by an amended water wash, followed by HEPA vacuuming. Porous surfaces such as carpets, furniture, ceiling tiles (and support grids), office partitions, at'td other soft goods must be evaluated for the feasibility of cleaning. If surfaces can not be cleaned they must be discarded. The electrical equipment must be evaluated and specially cleaned or discarded.

The asbestos cleaning started with the floors most needed by the American Stock Exchange and proceeded to other floors or a priority basis. Asbestos fibers fr3:m outside the building axed :from the 9"' floor of 22 Thames have not appeared to migrate to the other floats because the samples collected on show later

counts virtually days or all

zero for strictures

centimeter squared per

millimeter

per structures

squared.

The lead in air samples were collected from areas considered representative of the building. Only one sample was collected from each area to accelerate the building screening process. The lead in air

are

presented results below. table

e th in

Papa

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