The use of personal coal dust monitors in coal mines should be expanded to obtain accurate information about exposures to respirable coal dust, according to a report released in June by the National Academies of Science, Engineering, and Medicine. The report discusses an MSHA rule issued in 2014 that requires use of a device called a continuous personal dust monitor—a piece of wearable technology that provides real-time measurements of accumulated and full-shift exposures to respirable coal mine dust.  The rule, which went into effect in 2016, requires mine operators to take corrective action whenever a full-shift measurement exceeds the MSHA exposure limit for coal mine dust of 1.5 mg/m³. MSHA later reported that approximately 99 percent of the respirable coal mine dust samples collected during April, May, and June 2016 were in compliance.  But the National Academies report suggests those early results may be misleading. Because the rule requires only a few coal miners to wear a CPDM, monitoring based solely on results obtained from those devices might overlook higher exposures among miners who are not wearing CPDMs.  The National Academies report is available .