NYC-WTC_000215139

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan March 21, 2002 Wipe Samples for Dioxins Page 2 H. S. for Leadership & Public Service (894M) ATC Project No. 15-19125-0290

WIPE SAMPLING RESULTS

ATC submitted three (3) wipe samples for PCDDs/PCDFs (plus one blank) to Pace for analysis. A copy of the laboratory report is provided in Attachment 1. Samples were taken from areas specified by the parents association consultant. The sample area was one square meter (m^). The sample locations and the areas are shown in the table as well as the results

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 (m nanograms) for the analytical results for each sample. A copy of the analytical laboratory report is attached.

DIOXIN WIPE SAMPLE RESULTS (2, 3, 7, 8 TCDD EQUIVALENTS) February 14,2002 a DIOXINGONGENTRATION: f LOCATION/SAMPLE NUMBER Main Lobby Floor /DXl O.OOObO 5*^^ Floor by Elevator Floor /DX2 0.012 10th Floor by Elevator /DX3 0100024 Field Blank/DX9 0.00024

The concentrations on indoor surfaces ranged from 0.00024 to 0.012 nanograms per square meter (ng/m^). The levels found in all of these samples are below the NYSDOH guideline of 25 ng/m2.

It is not possible to determine when the 2, 3, 7, 8 - TCDD equivalents detected in these samples were deposited. Dioxin samples were not collected from these locations prior to January 2, 2002.

It is our pleasure to provide these indoor environmental services to the NYC Board of Education. If you have any questions about this report, please call (212) 353-8280, extension 212.

Sincerely, .4 TC ASSOCIA TES INC.

James R. Cohn, CIH, CSP Regional Manager Industrial Hygiene Division

Attachment

CITY_21MC100_002854252

NYC-WTC_000215140