August 23, 1996: Regulation Recommends Specific Method of Asbestos Testing

The current version of OSHA Regulation 1910.1001, “Polarized Light Microscopy of Asbestos—Non-Mandatory,” recommends the use of “transmission electron microscopy” (TEM) to test for the presence of asbestos instead of the older, less sensitive method, known as “polarized light microscopy” (PLM). The regulation notes that “TEM is a powerful tool to identify fibers too small to be resolved by light microscopy and should be used in conjunction with this method when necessary” and suggests that “when optical techniques [PLM] are inadequate, there is ample indication that alternative techniques [TEM and SEM] should be used for complete identification of the sample.” SEM, or “Scanning Electron Microscopy,” is another method that provides less analytical information about the asbestos fiber than TEM. [US Code, Vol. 29, sec. 1910.1001]