The current quartz (14808607) dust exposure enforcement program of the Mine Safety and Health Administration (MSHA) was discussed. Since the passage of the Federal Coal Mine and Safety Act in 1969 exposure to airborne quartz dust in coal mines has been controlled by reducing the dust standard whenever samples of coal mine dust were found to contain more than 5% quartz. The current MSHA enforcement program, which was established in December 1985, was designed to consider day to day variations in quartz exposures, allow use of a limited number of operator supplied dust samples to set the standard when the samples were found to contain more than 5% quartz, provide for subsequent monitoring of jobs, areas, or work positions (entities) that had been placed on a reduced standard, and provide for biannual reevaluations of entities that had been placed on a reduced standard. The quartz content of the samples was determined by an infrared spectroscopic technique. The procedure for adjusting a dust exposure standard was described. The current status of the quartz dust enforcement program was discussed. As of the end of fiscal year 1987 7418 MSHA, 1349 optional operator supplied, and 455 operator supplied 6 month dust samples had been analyzed for quartz. Approximately 33% of the MSHA samples, 36% of the operator optional, and 31% of the samples were out of compliance (contained more than 5% quartz). The highest quartz concentrations were found in samples from roof bolters and surface highwall drill operators. Only 42% of the operators who had the opportunity to submit samples did so. A total of 2044 entities were placed on a reduced standard because they were found to be out of compliance. In 74% of the biannual evaluations the quartz content of the samples was lower than the quartz concentration originally used to set the reduced standard. The authors conclude that although operator participation in the MSHA program has been less than expected, the program has had a positive effect on enhancing the level of health protection of American coal miners.