NYC-WTC_000223239

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan June 28, 2002 Wipe Samples for Dioxins Page 2 Stuwesant High School (M477) ATC Project No. 15-19125-0246

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. Copies of the laboratory analysis reports are attached. The results are shown in the following tables.

DIOXIN WIPE SAMPLE RESULTS 2,3,7, 8 TCDD EQUIVALENTS - Nanograms per square meter (ng/m^) May 15,2002 LOCATION/SAMPLE rO DIOXIN CONCENTRATION

I®’ Floor Lobby 0.00 Main Entrance / DXI 2^° Floor Lobby 0.00017 Bridge Entrance /DX2 HVAC#II/DX3 0.00037

DIOXIN WIPE SAMPLE RESULTS 2,3,7,8 TCDD EQUIVALENTS - Nanograms per square meter (ng/m^) May 22,2002 LOCATION /SAMPLE ID DIOXINeONGENTRATION

Floor Lobby 0.00 Main Entrance / DXI 2^^ Floor Lobby 0.00 Bridge Entrance /DX2 HVAC # 1/ DX3 0.00

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^).

On May 15^, the concentrations on indoor surfaces ranged from 0.00 to 0.00037 nanograms per square meter (ng/m^). On May 22nd, the concentrations on all indoor surfaces were 0.00 nanograms per square meter (ng/m^). The levels found in all of these samples are below the NYSDOH guideline of 25 ng/m^.

It is not possible to determine when the 2, 3, 7, 8 - TCDD equivalents detected in this sample was deposited. Dioxin samples were not collected from these locations prior to November 8, 2001, and therefore a background sample is not available for comparison purposes.

CITY_21MC100_002889946

NYC-WTC_000223240