Asbestiform Minerals In Industrial Talcs: Commercial Definitions Versus Industrial Hygiene Reality.
Workshop on Asbestos: Definitions and Measurement Methods, National Bureau of Standards, U.S. Department of Commerce, NBS Special Publication No. 506 1978 Nov:313-323
The asbestiform content of talc (14807966) was investigated during mining and milling operations. Bulk and airborne samples were analyzed by NIOSH industrial hygienists using an analytical transmission electron microscope. Fiber identification was achieved using selected area electron diffraction and X-ray microchemical analysis. Samples had been certified by the company to be asbestos (1332214) free as analyzed by optical microscopy. NIOSH studies using the optical microscope indicated that 18.2 fibers per cubic centimeter (fibers/cm3) was present in the mine and 29.1 fibers/cm3 in the mill at peak concentrations. Concentrations of asbestos fibers using transmission electron microscopy were 25 fibers/cm3 in the mine and 102 fibers/cm3 in the mill. About 17 percent of airborne fibers were tremolite (14567738), about 41 percent were anthophyllite (16829439), and 38 percent could not be identified. Over 90 percent of the positive amphibole fibers were less than 5 micrometers in length. The author concludes that users of asbestos products have a right to know that they have potential exposures to hazardous substances so that proper precautions can be taken. The establishment of a standard for mineral fibers is suggested.
Fibrous-dusts; Chemical-analysis; Air-contamination; Asbestos-dusts; Dusts; Air-monitoring; Air-sampling; Airborne-dusts; Safety-education; Safety-equipment;
14807-96-6; 1332-21-4; 14567-73-8; 16829-43-9;
Workshop on Asbestos: Definitions and Measurement Methods, National Bureau of Standards, U.S. Department of Commerce, NBS Special Publication No. 506