NYC-WTC_000224758

NYC 9/11 Public Portal Document

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

May 13, 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

Re; Air Sampling for Silica P.S. 150M ATC Project No. 15-19125-0289

Dear Mr. Orlan:

ATC Associates, Inc. (ATC) is pleased to provide this letter report of air sampling for silica-containing dust conducted on April 8 and 15, 2002, at the referenced school. The New York City Board of Education (BOE) requested this sampling at the recommendation of Environ Corp., the consultant to the parents association.

Scope of Work

On each day, ATC collected four (4) 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 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. Copies of the analytical laboratory reports are attached.

Wagdi Abdelshahid and Tenzin Namgyal, Industrial Hygienists of ATC’s New York City office, collected the samples 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. The results of the sampling represent conditions found on the dates of the samples were collected.

Results

On 4/8/02, samples were obtained in the Main Lobby, Multipurpose Room, Classroom 401 and Classroom 403.

CITY_21MC1OO_OO2894448

NYC-WTC_000224758