AHERA: Asbestos Hazard Emergency Response Act (1986); legislation requiring the cataloging of asbestos containing building materials in schools.
Asbestiform: tending to separate into fibers having length:width ratios from 10:1 to over 100:1.
Asbestos: any of a group of commercially mined minerals that tend to break into fibers. The regulated asbestos minerals are the serpentine mineral chrysotile and the asbestiform varieties of the amphibole minerals grunerite (amosite), riebeckite (crocidilite), tremolite, actinolite and anthophylitte. Amphibole minerals occure in both the regulated, asbestiform varieties and the non-regulated, non-asbestiform varieties. The fibers are resistant to high temperatures, have high tensile strength, and in some cases can be woven into cloth.
Asbestosis: a chronic fibrosis of the lungs caused by large exposures to asbestos, usually affecting miners, ship-builders and mill-workers.
EPA: Environmental Protection Agency; environmental issues government agency.
f/cc: fibers per cubic centimeter; reporting units for PCM analyses.
friable: able to be crumbled to powder by hand pressure when dry.
mesothelioma: cancer of the lining of the lung or intestines.
MFL: millions of fibers per liter of water; reporting units for TEM analysis of water samples.
NESHAP: National Emission Standard for Hazardous Air Pollutants (rev. 1996).
Non-asbestiform: tending to break into cleavage fragments having length:width ratios from 2:! to 20:1.
OSHA: Occupational Safety & Health Administration; requires that workers be protected from asbestos exposure.
PCM: phase-contrast microscope, an optical microscope used to perform fiber counts on air sample filters. Its disadvantages for asbestos analysis are that 1) it cannot resolve all asbestos fibers, and 2) it cannot distinguish asbestos fibers from other fibers.
PEL: permissible exposure limit; OSHA mandated maximum level for workers without respiratory protection (8 hour time weighted average).
structures/mm2: asbestos structures, as defined by AHERA (fiber, bundle, matrix or cluster), per square millimeter of filter; reporting units for AHERA TEM analyses.
TEM: transmission electron microscope, highly technical equipment used to perform asbestos analysis on air samples. It can resolve and distinguish all asbestos fibers from other fibers.