NYC-WTC_000175337

9/11 Public Portal Document

104 East 25th St., 10th New York, New York 100’ www.atc-enviro.co 212.353.82t Fax 212.353.83( ASSOCIATES INC.

September 20, 2002

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

Re: Air Sampling for Silica Murray Bergtraum High School (M520) ATC Project No. 15-19125-0351

Dear Mr. Orlan:

ATC Associates Inc. (ATC) is pleased to provide this report of the results of air monitoring for silica-containing dust conducted on September 11, 2002, at the referenced school. The New York City Department of Education (DOE) requested this monitoring prior to the resumption of classes to verify that acceptable indoor air quality is being maintained.

Scope of Work

ATC collected a total of three (3) samples (and one blank) 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 indoor?. The samples 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 according to OSHA Method 142. A copy of the analytical report is attached.

Tenzin Namgyal, Industrial Hygienist, and Sonny Ramlal, Environmental Technician of ATC’s New York City office, collected the samples consistent with generally accepted industrial hygiene practices. The results of the sampling represent conditions found on the date the samples were collected.

Results

Samples were obtained in the following locations; floor Main Lobby, 3^^ floor hallway by Room 339 and 5^^^ floor hallway by Room 518.

The results of all of the samples were below the detection limit for silica (<5.0 micrograms per sample).

CONriDENIIAL, CIIY^200J„3422277 SDBJECI IO PROTECTIVE ORDER KO. 2, SEPT. 2008

NYC-WTC_000175337