Document page fragment, DEP Box 54, 2003

NYC 9/11 Public Portal Document 04/23/2083 11:31 18568589551 EMSL ANALYTICAL PAGE 02

EMSL Analytical, Inc. 107 Haddon Ave., Westmont, NJ 08108

• Order ID:040305286 Attn: Andrew/ M.N. Khan Customer ID: JLCC50 JLC Environmental Consultants, Inc. Customer PO: 200 Park Ave South, Suite 1001 Date Received: 04/05/03 12:23 AM New York, NY 10003 Fax: 212-420-6092 EMSL Order: 040305286 Project: #03-2744/NYCDEP-114 Liberty ST EMSL Project ID: Report Date: 04/14/03 Date Analyzed: 04/14/03

Silica, Crystalline Analysis Performed X-Ray Diffraction (XRD) Modified NIOSH Method 7500, Issue 3, I/I5/98

e Dust Airborne Silica Sample Sample Silica Silica % Analytical Sample ID I Identification Particle Volume Weight Cone. Weight Conc. Silica Sensitivity ID (L) (mg) (mg/m3) (lag) (mg/m3) (mg/m3)

3RD FLR APARTMENT 408 1 0.143 0.3505 1 <0.0045 1 <0.0110 1 3.1 1 0.0110

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Disclaimer: The laboratory can only verify the concentration of silica on the filter and not the final concentration due to data obtained by non-laboratory personnel. In the absence of a bulk dust sample, neither the specific forms of crystalline silica aor, the interf species can be fully determined, Hence, the amount for each phase, if anticipated, will be analyzed based on primary, secondary, and/or tertiary peak data with comparison to calibration curves of known standards. It should be noted that air samples are meant for only quantifying silica (or a mineral phase) which must first be identified from a bulk dust sample. "<" means less than the stated value. The lowest reportable value Is equivalent to the Analytical Sensitivity that is calculated from the lowest reproducible amount of specific mineral detectable by the instrument.

Anant Samudra, Ph.D. Analyst Stephen Siegel, ('1,I- Lab Manager Or other approved signatory .A ,uA Accredited- Laboratory I D #100194 Page 2 of 3

NYC-WTC 000132103