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Asbestos particles examined by microscope:
Photographs provided on this page illustrate what asbestos fibers or fragments may look like under the polarized light microscope.
In this article we provide photographs and descriptive text of asbestos insulation and other asbestos-containing products
to permit identification of definite, probable, or possible asbestos materials in buildings. This document assists forensic investigators, laboratories, building buyers, owners or inspectors who need to identify asbestos materials (or probable-asbestos) in buildings by simple
visual inspection and confirmed by asbestos test lab or forensic microscopy lab examination.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
Asbestos under the microscope: Micro photographs of Asbestos
While an expert lab test using polarized light microscopy may be needed to identify the specific type of
asbestos fiber, or to identify the presence of asbestos in air or dust samples, many asbestos-containing building products
not only are obvious and easy to recognize, but since there were not other look-alike products that were not asbestos, a visual identification of this material can be virtually a certainty in many cases.
Our photo (left) illustrates pure tremolite asbestos used as fireproofing on a building ceiling in New York. Our forensic lab photographs of tremolite asbestos (below) were collected from that ceiling. More about this building can be read
at ASBESTOS FIREPROOFING SPRAY-On Coatings.
see ASBESTOS DUCTS, HVAC a field identification guide to
visual detection of asbestos in and on heating and cooling system ducts and flue vents,
PLM (Polarized Light Microscopy) remains the most-commonly or widely used method for identifying asbestos: with proper training, equipment, a polarized light microscope, (ideally sporting one or more central stop dispersion staining lenses) and the proper immersion oil in the right range of refractive index, this is quick, efficient, easy.
A second, widely-used means of identification of asbestos in material samples is the use of SEM (Scanning Electron Microscopy) or TEM (Transmission Electron Microscopy) - approaches using a directed beam of electrons, an X-ray or EDX (energy-dispersive X-rays) beam, and proper computer software and hardware in support. This approach has the benefit of easier identification of different types of asbestos, thouigh McCrone also showed that asbestos types could also be identified by his methodology.
SEM's are of course a higher-resolution technology than a PLM that is generally limited to particles down to about 1u at 1200x or smaller particles at 1920x magnification (using our POLAM Russian-built PLM).
TEM has still higher resolution. However in our OPINION as well as that of experts, PLM is completely adequate for identifying asbestos in bulk, air, or dust samples.
Here are two photographs showing what a sample of asbestos ceiling fireproofing (tremolite asbestos) looks like in
our lab microscope using polarized light microscopy (PLM).
in the first photo you see long very thin multi-fibrous filaments - asbestiform tremolite.
Each filament is less than one micron in diameter. In the second photograph
you'll observe non-fibrous granular particles, many less than one micron in diameter as well -
non-asbestiform tremolite. [McCrone]
This asbestos sample was collected from slabs of nearly pure tremolite asbestos which was
as FIREPROOFING ASBESTOS SPRAY-ON in
a commercial building.
McCrone illustrated that tremolite asbestos (as well as some other forms of asbestos) occur in both fibrous and non-fibrous form.
Comparing the photo at below left (tremolite in fibrous form) by McCrone to ours (above right) that shows fewer small non-fibrous particles, but a clear bundle of ultra-fine sub-micron (in width) fibers.
Asbestos Identification Resources
EPA Guidance for Controlling Asbestos-Containing Materials in buildings, NIAST, National Institute on Abatement Sciences & Technology, [republishing EPA public documents] 1985 ed., Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
ASBESTOS IN YOUR HOME U.S. EPA, Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
Asbestos products and their history and use in various building materials such as asphalt and vinyl flooring includes discussion which draws on ASBESTOS, ITS INDUSTRIAL APPLICATIONS, ROSATO 1959, D.V. Rosato, engineering consultant, Newton, MA, Reinhold Publishing, 1959 Library of Congress Catalog Card No.: 59-12535 (out of print, text and images available at InspectAPedia.com).
De Stefano, L., and F. De Luca. "SEM Quantitative Determination of Asbestos in Bulk Materials." MICROSCOPY AND ANALYSIS (2002): 13-16.
McCrone, Walter C., Asbestos Identification, [book for sale at Amazon] McCrone Research Institute, Chicago, IL.1987 ISBN 0-904962-11-3. Dr. McCrone literally "wrote the book" on asbestos identification procedures which formed
the basis for current work by asbestos identification laboratories.
McCrone, Walter C., Lucy B. McCrone, John Gustav Delly, "Polarized Light Microscopy", McCrone Research Institute, Chicago (2003 Fourteenth printing) , original copy 1984, ISBN 0-250-40262-9.
This volume is in reality a recent edition of a course manual first preapred by Walter C. McCrone and Marven Salzenstein in 1959. [The first] hard-cover edition was printed in 1977.
Disclosure: InspectApedia's editor/author took this course as a stuednt at McResearch Institute in 2003.- Ed.
Stanton, .F., et al., National Bureau of Standards Special Publication 506: 143-151
Pott, F., Staub-Reinhalf Luft 38, 486-490 (1978) cited by McCrone
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asbestos fibers in the nose?
(Nov 2, 2014) Doreen said:
If asbestos fibers get trapped in nose and sinus that are open and/or infected,can serious harm occur? If so, in what way? I believe I may be being exposed and am suffering some severe effects.
Large fibers of asbestos, cloth, lint, etc. that are "trapped' in the nose are normally secreted, e.g. when you blow your nose or clean it.
Large fibers of any material that are breathed into the lungs are typically exhaled or coughed out or lodge high in the lung.
Small particles of any material, including asbestos fibers, are more dangerous as they are easily breathed deeply into the lungs and are not so easily expelled. Worse, Smokers have an 80 times greater risk of lung cancer related to radon exposure and I suspect similar hazards apply to inhalation of other small particles by smokers, including asbestos or silica.
Doreen you should take your concerns to your doctor.
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