Silica dust air sampling report, February 26, 2002

NYC 9/11 Public Portal Document

104 East 25th St New York, New York 10010 w'ww.atc-enviro.com 212,353.8280 Fax 212.353.8306 ASSOCIATES INC.

February 26, 2002

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

Re; Silica Dust Assessment High School for Leadership and Public Service 90 Trinity Place New York, New York ATC Project No. 15-19125-0290

Dear Mr. Orlari:

ATC Associates, Inc. (ATC) is pleased to provide this letter report of air sampling for silica-containirig dust conducted on February 8, 2002, at the referenced school. The New York City Board cT Education (BOE) requested this sampling to assess the concentration of silica (total quartz) in the respirable particulates within the building.

SCOPE OF WORK

ATC collected th-ee (3) samples for respirable particulates 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 three samples were collected indoors. The samples, plus one blank filter, were sent to PSC Analytical Services, Inc., an American Industrial Hygiene Association accredited laboratory in Reading, PA. Analysis was performed by x-ray diffraction 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.

The assessment v/as performed consistent with generally accepted industrial hygiene assessment practices. As with all such assessments, there were inherent limitations created by constraints of time, operational and work practice variability, variations in air contaminant concentrations and sampling and analytical accuracy.

CONFIDENTIAL, CITY_21MC1OO_OO3432122 SUBJECT TO PROTECTIVE ORDER NO. 2, SEPT. 2008

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