coal dust in mines, to protect workers from exposure to coal mine dust which leads to black lung disease and progressive massive fibrosis. Prior to the introduction of CPDMs, dust particles collected on a filter needed to be analyzed in a laboratory, leading to a delay of weeks in obtaining results. Continuous monitoring allows miners to take corrective action such as moving to another area or changing their activities if dust levels exceed exposure limits. In one study this led to a 90% reduction in samples exceeding the dust exposure limit. In February 2016, the U.S. Mine Safety and Health Administration (MSHA) mandated the use of CPDMs on working sections of underground coal mines, and for workers who have evidence of the development of pneumoconiosis. As of 2017, the only CPDM instrument approved by MSHA uses a TEOM. As of 2013, TEOM was not considered suitable for workplace monitoring of nanomaterials due to its cut-off particle sizes of 10, 2.5, or 1 μm, and the physical size of the instrument. History TEOM is a proprietary technology developed by Rupprecht and Patashnick Co., Inc. of Albany, New York, whose successor company (as of 2005) is Thermo Fisher Scientific. "TEOM" is a registered trademark. It was originally developed as a fixed-site environmental particulate mass monitor, and TEOM aerosol detectors were available in 1981. Development of the continuous personal dust monitor was originally performed by Rupprecht and Patashnick Co., Inc. and continued by Thermo Fisher under contract from the U.S. National Institute for Occupational Safety and Health with input from other government, labor, and industry organizations. Machine-mounted continuous dust monitors have been available since 1997. References Further reading Aerosol measurement Mine safety Air pollution Weighing instruments