NYC-WTC_000196717

NYC 9/11 Public Portal Document

' Mr. Bernard P. Orian November 25, 2002 Wipe Samples for Dioxins Page 2 P. S 1 (Manhattan) ATC Protect No 15-19125-0340

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. A copy of the laboratory analysis report is attached. The results are shown in the following table.

DIOXIN WIPE SAMPLE RESULTS 2, 3, 7, 8 TCDD EQUIVALENTS - Nanograms per square meter (ng/m^) August 27, 2002 LOCATION/SAMPLE ID DIOXIN CONCENTRATION

Main Lobby/DXl 0.000083

Hallway by Room 215 /DX2 0.00018

Hallway by Room 403 / DX3 0.000045

The New York State Department of Health (NYSDOH) established guidelines for dioxin for the re-occupancy of the Binghamton State Office Building following a PCB fire. The NYSDOH guideline for dioxin on surfaces is 25 nanograms per square meter (25 ng/m^).

The concentrations on indoor surfaces ranged from 0.000045 to 0.00018 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 was deposited. Dioxin samples were not collected from these locations prior to these samples therefore a background sample is not available for comparison purposes.

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

Sincerely, ATC Associates, Inc.

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

Attachment

CITY_21MC1OO_OO3O42417

NYC-WTC_000196718