NYC-WTC_000196122

NYC 9/11 Public Portal Document

Re: Environmental Testing Page 2 of 3

If asbestos fibers enter a building they may remain airborne or settle onto fixed surfaces (primarily horizontal surfaces). Asbestos air and surface dust samples were taken on each floor of the building, including the second floor interior sill where visible dust was observed by occupants after the disaster. Dust samples were also taken from filters in two portable air cleaners used since the space was re-occupied.

Asbestos Air Sampling

Six air samples were taken and analyzed by an accredited asbestos laboratory using transmission electron microscopy (TEM). TEM analysis is very accurate for finding even trace amounts of asbestos fibers present in the air.

The United States Environmental Protection Agency (EPA) has established a protocol for determining whether school areas are safe for re-occupancy after completion of asbestos abatement projects. This procedure is covered by EPA 40 CFR Part 763, Asbestos-Containing Materials in Schools. The procedures state that the average asbestos airborne fiber level in the abated work area must be less than 70 asbestos structures per square millimeter (AS/mm^).

The laboratory results from the testing on October 19, found no asbestos structures present in 5 of the samples. One sample had one asbestos structure (fiber) present and the total level was well below the allowable 70 AS/mm^. Reference the attached laboratory results from EMSL Analytical. Very low levels of asbestos exist in the New York City urban environment. One sample with a single asbestos structure present in a total sampling of 6 is considered statistically insignificant.

Asbestos Surface Sampling

Asbestos settled dust sampling was performed in 16 locations inside the building, and at both air handling unit outdoor air intakes. The samples were analyzed by the accredited asbestos laboratory using polarized light microscopy (PLM). All 18 samples had no asbestos detected.

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NYC-WTC_000196123