NYC-WTC_000213043

NYC 9/11 Public Portal Document

Sampling Methodology

ATC provided all laboratory analytical services in support of this inspection. ATC is certified by the New York State Department of Health’s Environmental Laboratory Accreditation Program to perform lead and related analyses of environmental samples (Laboratory ID Number: 10879). The laboratory utilizes die United States Environmental Protection Agency analysis method number SW846-7420 and the National Institute of Occupational Safety and Health method number 7082M.

The samples were obtained by gently wiping a measured surface area with non-alcohol moistened towelettes. ATC’s representative wore disposable gloves; new gloves were worn with each new sample collected, and special care was taken to avoid contamination of the towelette and collection vial. Samples were then placed into 50ml plastic vials and immediately sealed. The chain of custody form was completed documenting the exact locations and measurements of the areas sampled.

Results of Dust Wipe Sampling

A total of ten (10) dust wipe samples were collected from the above referenced locations. Laboratory analysis indicated that seven (7) of the ten (10) samples collected from unit ventilator surfaces were above the guideline level of 250 pg/fF for window sills. The remaining three (3) samples were above the guideline level 40 pg/ft^ for floors but below 250 pg/ft^. The laboratory report and chain of custody forms for the samples collected are included in the Appendix of this report.

Limitations of dust wipe sampling

Lead wipe sampling was conducted at NYC-BOE request. The results of this report are applicable for the time the testing was performed. ATC makes no representations or warranties concerning the standards and specifications provided in the EPA and/or HUD Guidelines related to lead wipe sampling and interpretation of these sample results.

It is our pleasure to provide these services to New York City Board of Education. Should you have any questions regarding these sample results, please do not hesitate to contact me at (212) 353-8280 extension #211-

Sincerely, A TC Associates, Inc.

Yiannis Efstathiou Senior Project Manager

IS306X TC 1*1 «• l«C May 2, 2002

CITY_21MC100_002868068

NYC-WTC_000213045