NYC-WTC_000234332

NYC 9/11 Public Portal Document

EMSL Analytical, Inc. 107 Haddon Ave., Westmont, NJ 08108 EMSU OrderID:040300857 Attn: Nitin Dave Customer ID: TRCE51 TRC Environmental Consultants Customer PC: 134 West 29'*’ Street Received: 1/21/03 10:49 AM Penthouse New York, NY 10001 Fax: 212-221-7822 EMSL Order: 040300857 Project; #35052-0000-00016/NYC LAW DEPT.- EMSL Project ID: OFFICE EQUIP. SIM. AIR SAMPLING Report Date: 1/23/03 Date Analyzed; 1/22/03

Silica, Crystalline Analysis Performed X-Ray Diffraction (XRD) NIOSH Method 7500, Issue 3,1/15/98

Respirable Dust Airborne Silica Sample Sample Silica Silica % Analytical Sample ED Identification Particle Vol Weight Cone. Weight Cone. Silica Sensitivity ID (L) (mg) (mg/m') (mg) (mg/ra’) (mg/m^)

NAOI 1903 SILOSHAl 001 FIELD BLANK Quartz 0 <0.002 ■N/A <0.0045 N/A N/A N/A 040300857-0001 NA011903SILOSHA1002 NA2AR Quartz 1198 <0.002 <0.002 <0.0045 <0.0038 N/A 0.0038 040300857-0002 AGAHAN NA011903SILOSHA1003 MIKHAIL Quartz 1198 0.019 0.0159 <0.0045 <0.0038 N/A 0.0038 040300857-0004 SHINDELMAN

Silica Standard 0.050Q Quartz 0 N/A N/A 0.047 N/A N/A N/A

Notes; 1. Bulk sample not submitted with sample set. 2. Discernable field blank submitted with sample set. 3. Results are not field blank corrected. 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 nor the interfering 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, CIH- Lab Manager Or other approved signatory I AIHA Accredited - Laboratory ID #100191 Page 1 of 1

CITY_21MC100_007139719

NYC-WTC_000234332