NYC-WTC_000214929

NYC 9/11 Public Portal Document

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

April 24, 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'll 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 respirdble 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 date the samples were collected.

Results

Samples were obtained in the following locations: pt floor Hallway, Cafeteria, Gymnasium, Auditorium, Room 211 (South), Room 219 (South) and Room 216 (East).

Silica was detected in three of the seven samples as follows: Sample #S1 ATC-0326-234M(lst floor hallway) - 0.0127 mg/m^ Sample #S2 ATC-0326-234M (Cafeteria) - 0.0157 mg/m3 Sample #S5 ATC-0326-234M (Room 211-South) - 0.0136 mg/m^

CITY_21MC100_000463467 NYC-WTC_000214929