NYC-WTC_000196719

NYC 9/11 Public Portal Document

Mr. Bernard P Orlan November 25, 2002 Wipe Samples for Dioxms Page 2 P S 1 (Manhattan) ATCProiectNo 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-dioxm (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 laboratory analysis report is attached. The results are shown m 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

Mam 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 m 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 m 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_21MC100_003042434

NYC-WTC_000196720