PCDD/PCDF wipe sample results, June 7, 2002

NYC 9/11 Public Portal Document

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

June 7, 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: Wipe Samples for Dioxins High School for Leadership and Public Service (M894) ATC Project No. 15-19125-0290

Dear Mr. Orlan:

ATC Associates Inc. (ATC) is pleased to provide this report of the results of the wipe samples for polychlorinated dibenzo-p-dioxins (PCDDs)and dibenzo furans (PCDFs) collected on May 3, 2002 at the referenced location. The New York City Board of Education (BOE) requested these samples to evaluate possible contamination in the school building.

SCOPEOF 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 m 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 dates the samples were collected.

WIPE SAMPLING RESULTS

On each day, ATC submitted three (3) wipe samples for PCDDs/PCDFs to Pace for analysis. A copy of the laboratory analysis report is provided in the Attachment. Samples were taken from areas in various parts of the building. The sample area was one square meter (1 m^).

Each sample was analyzed for sixteen (16) PCDC7PCDF isomers. The results for each isomer were then converted to 2, 3, 7, 8 -tetrachloro-dibenzo-p-dioxm (2, 3, 7, 8-TCDD) equivalents by multiplying by an established equivalency factor.

CONFIDENTIAL, CITY_21MC100_003432099 SUBJECT TO PROTECTIVE ORDER NO. 2, SEPT. 2008

NYC-WTC_000175644