The U.S. Department of Labor announced on April 16 that its Mine Safety and Health Administration has issued a final rule to better protect the nation’s miners from health hazards associated with exposure to respirable crystalline silica, also known as silica dust or quartz dust.
The final rule lowers the permissible exposure limit of respirable crystalline silica to 50 micrograms per cubic meter of air for a full-shift exposure, calculated as an 8-hour time-weighted average. If a miner’s exposure exceeds the limit, the final rule requires mine operators to take immediate corrective actions to come into compliance.
Water well contractors can also be exposed to silica dust hazards at jobsites, and it's important to look controls to limit the hazard and consider respirator use (video by John Fowler, CSP, CMSP).
In addition to reducing exposure limits, the final rule does the following:
- Requires mine operators to use engineering controls to prevent miners’ overexposures to silica dust and use dust samplings and environmental evaluations to monitor exposures.
- Compels metal and nonmetal mine operators to establish medical surveillance programs to provide periodic health examinations at no cost to miners. The exams are similar to the medical surveillance programs available to coal miners under existing standards.
- Replaces an outdated standard for respiratory protection with a new standard reflecting the latest advances in respiratory protection and practices. This update will better protect miners against airborne hazards, including silica dust, diesel particulate matter, asbestos and other contaminants.
Inhalation of respirable crystalline silica, a carcinogen, can cause serious lung and other diseases, such as silicosis, lung cancer, progressive massive fibrosis, chronic bronchitis and kidney disease. Exposure to mixed coal mine dust containing respirable crystalline silica can lead to the development of black lung disease and progressive massive fibrosis. These diseases are irreversible and can be fatal. They are also preventable.
MSHA’s final rule will improve the health and safety of U.S. miners significantly. The rule will result in an estimated total of 1067 lifetime avoided deaths and 3746 lifetime avoided cases of silica-related illnesses.
Click here to read MSHA’s silica rule.