NYC-WTC_000199084

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.

April 4, 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 P. S. 234M ATC Project No. 15-19125-0279

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 March 19, 2002, at the referenced school. The New York City Board of Education (BOE) requested this monitoring at the recommendation of Environ Corp., the consultant to the parents association.

Scope of Work

ATC collected a total of seven (7) 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 indoors. 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 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 dates the samples were collected.

Results

Samples were obtained in the following locations; 1®^ floor Hallway, Cafeteria, Gymnasium, Auditorium, Room 305 (South), Room 315 (South) and Room 316 (East).

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

CITY_21MC100_003031241

NYC-WTC_000199084