NYC-WTC_000227074

NYC 9/11 Public Portal Document

104 East 25th St., 10th Floor New York. New York 10010 k www.atc-enviro.com 212.353.8280 Fax 212.353.8306 ASSOCIATES INC.

April 2,2002

Mr. Bernard P. Orlan Director, Environmental Health & Safety New York City Board of Education 28-11 Queens Plaza North Long Island City, NY 11101-4008

Re: Air Sampling for Silica Higlh SchooS offEcomomics and Fimamce (M833) 100 Trinity Place New York, New York ATC Project No. 15-19125-0291

Dear Mr. Orlan:

ATC Associates Inc. (ATC) is pleased to provide this report of the results of air sampling for silica-containing dust conducted on March 9, 2002, at the referenced school. The New York City Board of Education (BOE) requested this monitoring to evaluate possible contamination in the building.

Scomie off Work

ATC collected three (3) samples for respirable dust using pre-weighed 37mm PVC filters connected to size-selective cyclones to remove the larger (non-respirable) particles prior to deposition on the filters. All of the samples were collected indoors. The samples (and one blank) were sent to PSC Analytical Services, Inc., an American Industrial Hygiene Association accredited laboratory in Reading, PA. Analysis for silica was performed by x-ray diffraction f according to OSHA Method 142. A copy of the analytical report is attached.

Tenzin Namgyal and Wagdi Abdelshahid, Industrial Hygienists of ATC’s New York City office, collected the samples consistent with generally accepted industrial hygiene practices. As with all such sampling, there were inherent limitations created by constraints of time, operational and work practice variability, variations in air contaminant concentrations and sampling and analytical accuracy. The results of the sampling represent conditions found on the date the samples were collected.

BesmWs

Samples were obtained in the following locations: 1st floor Main Lobby, 5th floor by the elevator and 10th floor by Stair B.

The results of all of the samples were reported to be below the detecdon limit for silica (<10.0 micrograms per sample).

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