NYC-WTC_000196829

NYC 9/11 Public Portal Document

104 East 25th St., 10th Floor New York, New York 10010 WWW atc-enviro.com 212.353.8280 ASSOCIATES INC. Fax 212 353.8306

January 22, 2003

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: Wipe Samples for Dioxins P. S. 89M ATC Project No. 15-19125-0297

Dear Mr. Orlan:

ATC Associates Inc. (ATC) is pleased to provide this report of the results of the wipe samples for polychlorinated dibenzo-p-dioxms (PCDDs)and dibenzofurans (PCDFs) collected on December 27, 2002 at the referenced location. The New York City Board of Education (BOE) requested these samples to evaluate possible contamination in the school building.

SCOPE OF WORK

The samples were collected using gauze pads and hexane as a solvent. The pads and solvent were provided and samples were analyzed by Pace Analytical Services, Inc. (Pace) of Minneapolis, MN, a laboratory experienced in dioxin analysis. The analysis was performed by modified EPA Method 8290 using combined capillary column gas chromatography/high resolution mass spectrometry.

Wagdi Abdelshahid, Industrial Hygienist of ATC’s New York City office, collected the samples consistent with generally accepted industrial hygiene practices. There were inherent limitations created by constraints of time, operational and work practice variability, variations in contaminant concentrations, and sampling and analytical accuracy. The results of the sampling represent conditions found on the date the samples were collected.

WIPE SAMPLING RESULTS

ATC submitted three (3) wipe samples for PCDDs/PCDFs to Pace for analysis. A copy of the laboratory analysis report is provided m the Attachment. The area of each sample one (1) square meter (Im^).

Each sample was analyzed for sixteen (16) PCDD/PCDF isomers. The results for each isomer were then converted to 2, 3, 7, 8 -tetrachloro-dibenzo-p-dioxin (2, 3, 7, 8-TCDD) equivalents by multiplying by an established equivalency factor. This provides a single value (in nanograms) for the analytical results for each sample.

CITY_21MC100_003043087

NYC-WTC_000196829