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OSHA Method ID-213: Tungsten and Cobalt in Workplace Atmospheres (ICP Analysis)
Description
This method describes the sample collection and analysis of airborne tungsten (W) and cobalt (Co). Most industrial exposures to W also involve exposures to Co (5.1). Tungsten carbide (WC or W2C) materials used for abrasives and cutting tools are frequently made containing Co metal which adheres to the surface of the hard but brittle tungsten carbide grains and cements them together into a tough composite. Other common components of cemented tungsten carbide materials include intermetallic compounds of W and Co (e.g., Co6W6C) in addition to other metals and their carbides. Because Co often occurs at significant levels in these materials, it is potentially present in airborne dusts along with W when tungsten carbide composites are used in the workplace. The Co component of cemented tungsten carbides has often been attributed as the etiological agent for certain occupational diseases observed in the tungsten carbide industry (5.1, 5.2). For these reasons, the sampling and analysis of Co was included in this method. Air samples are taken in the breathing zone of workplace personnel. Wipe and bulk samples can also be taken. Analysis is performed for elemental W and Co by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES).
During abrasive cutting or grinding, the matrix being cut or ground can aerosolize in addition to the grinding agent itself. The method is also suitable for screening other elements such as Al, As, Be, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sb, Se, Si, Sn, Te, Ti, V, Zn, and Zr.
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