Chain of custody form, 21 West Street, Nov 2001

NYC 9/11 Public Portal Document FEB-28-2002 THU 11:22 AM CLOSINGS 0 ROSE FAX NO. 212 210 6724 P. 41/42

Rose Associates page 2 JLC Projoct f# 01-2089 Bulk Buiidinq aterials Analysis.and_ rocedure

Introduction Polarized light microscopy with dispersion staining (PLM-DS) is the most efficient method for detecting asbestos in bulk samples. It is this method that the JLC lab uses during bulk building material anaiyses,

Methodology A chain of custody is kept for each sample to ensure proper handling and delivery to the JLC lab prior to analysis. To avoid any possible contamination, all sample and slide preparation is carried out in a ventilated, HEPA-filter hood with continuous airflow. Sample analysis Is performed using PLM-DS in eocordance with the USEPA , "Method for the Determination of Asbestos in Bulk Building Materials," EPA 600 R-93 116, July 1903, and NYDOH-ELAP certification manual, "Polarized Light Microscope Methods for Identifying and Quantitating Asbcctoc in Bulk Samples," FLAP 198.1, October 1993.

Analytical Procedures All samploa Oro oubject to preliminary visual stereomicroscopic examination. Observation of hnmog neity, fiber identification, and semi-quantitation of constituents can be made at this point. Samples lacking uniformity of composition and/or distribution of cornponont matoriala then undergo homogenization. Some non-friable organically bound (NOR) samples such as floor tiles and roofing materials may require additional stops to dislodge problem matrices (i.e. ashing, extractiuns, and TEM). 1dentificatiorl,of suspect fibers is made by PLM analysis of subsamples. A microscope equipped with dual paled ing filters enables us to observe specific optical characteristics of each sample. Positive Identification of asbestos requires determination of the following optical properties: morphology, color and pleochroism, rOfractivc Indices, birefringence, extinction characteristics, and signs of elongation

Asbestos quantltetion is performed by point-counting procedure, a atanderd technique in petrography for determining the relative areas occupied by separate minerals in rock. An ocular reticle superimposes a point or points over the microscope's field of view. Tine number of points positioned directly above each kind of particle or fiber is recorded, A total of 400 points must be counted over at least eight different representative subsamples to complete analysis.

Polarized Light Microscopy JLC' uses an Olympus BHT-P Polarizing Microscope complete with polanzer, analyzer, port for wave retardation plate, 360 degree graduated rotating stage, substage condenser, lamp and lamp iris, eyepiece reticle, and 25 point Chalkley Point Array. Plane polarized light allows for the determination of refraction Indices relative to spar.Ific rxystallographic orientations. Morphology and color can also be observed under plane polarized light. Observation of particles or fibers while oriented between polarizing filters whose privileged vibration directions are perpendicular allows for determination of lsotropism/ anistrnpism, extinction characteristtcs of anisotropic particles, and calculation of birefringence. A retardation plate may be placed In the polarized light path for verification of signs of elongation.

Analytical Results The "Summary of Analytical Results" roprosonto tho rosults of analysis. Positive results mean the sample Is asbestos or contains more than one percent asbestos by weight. The results are generally sufficient for identification and quantitatton of major concentrations of kasbestos, However, it may be found that additional techniques may be necessary. Please be aware that PLM is not consistenly reliable in detecting asbestos In floor coverings and similar NOS materials. Before the material can be considered or treated as non-ashestnr; containing, confirmation must be made by quantitative Transmission Electron Microscopy

(TEM).

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