DOL Finalizes Silica Dust Reduction Rule


The U.S. Department of Labor’s Mine Safety and Health Administration recently issued a final rule to protect miners from exposure to respirable crystalline silica, also known as silica dust or quartz dust. 

According to the administration, the final rule will work to lower the acceptable exposure limit of silica dust to 50 micrograms per cubic meter of air for a full-shift exposure, which was calculated as an 8-hour time-weighted average.

The rule adds that if a miner’s exposure exceeds the limit, it will require mine operators to take corrective actions immediately to come into compliance.

“It is unconscionable that our nation’s miners have worked without adequate protection from silica dust despite it being a known health hazard for decades. Today, the Department of Labor has taken an important action to finally reduce miners’ exposure to toxic silica dust and protect them from suffering from preventable diseases,” said Acting Secretary Julie Su.

“Mining communities across the country should know that the Biden-Harris administration is determined to do what must be done to ensure that miners come home safe and healthy at the end of every day.”

On top of working to reduce exposure limits, the final rule also reportedly includes:

  • A requirement for mine operators to use engineering controls to reduce overexposures to silica dust, while also using dust samplings and environmental evaluations to monitor exposures;
  • Advice to metal and nonmetal mine operators to create medical surveillance programs for periodic health examinations at no cost to miners. The exams would reportedly be similar to the medical surveillance programs available to coal miners under current standards; and
  • The replacement of an outdated standard for respiratory protection with a new standard reflecting the latest advances in respiratory protection and practices. This may better protect miners against airborne hazards, including silica dust, diesel particulate matter, asbestos and other contaminants.

“This rule reducing miners’ exposures to toxic silica dust has been a long time in the making, and the nation’s miners deserve its health protections. Congress gave MSHA the authority to regulate toxic substances to protect miners from health hazards and made clear in the Mine Act that miners’ health and safety must always be our first priority and concern," said Assistant Secretary for Mine Safety and Health Chris Williamson.

“To further advance this directive, MSHA is committed to working together with everyone in the mining community to implement this rule successfully. No miner should ever have to sacrifice their health or lungs to provide for their family.”

The inhalation of respirable crystalline silica is reportedly known to cause serious lung and other diseases, like silicosis, lung cancer, progressive massive fibrosis, chronic bronchitis and kidney disease.

Exposure to mixed coal mine dust containing respirable crystalline silica can also reportedly lead to the development of black lung disease and progressive massive fibrosis. These diseases are irreversible and can be fatal. Though they are also preventable.

The MSHA expects this final rule to benefit the health and safety of U.S. miners, hopefully resulting in an estimated total of 1,067 lifetime avoided deaths and 3,746 lifetime avoided cases of silica-related illnesses.

Previous Silica Rulings

For the first time since 1971, the DOL’s Occupational Safety and Health Administration amended silica exposure regulations in a new proposed silica rule, in March 2016. The rule came in the form of two standards—one for construction, and one for general industry and maritime. The construction standard took effect in October 2017, with a 30-day grace period for enforcement, and the maritime standard took effect June 2018.

At the time, the rule still reduced the permissible exposure limit for crystalline silica to 50 micrograms per cubic meter of air, averaged over an eight-hour shift. That’s half of the old PEL of 100 micrograms per cubic meter. The rule also established an action level of 25 micrograms per cubic meter.

In October 2017, the 30-day enforcement grace period for the new standard ended and a memorandum released by former Deputy Assistant Secretary Thomas Galassi outlined interim enforcement guidelines that had taken effect.

By May 2018—six months into its enforcement of its new silica rule—OSHA cited more than 100 companies, most commonly for employers’ failure to measure silica levels at all.

Other citations included variations of employers incorrectly following Table 1 procedures. (Table 1 refers to the “Specified Exposure Control Methods When Working With Materials Containing Silica” chart, which was released with the guidelines for the new rule.)

However, in August 2019, OSHA again requested industry feedback on its respirable crystalline silica standard as it applied to construction.

In December 2019, OSHA released its long-term regulatory agenda, highlighting that that upcoming June, the Administration would issue its proposed rule on Occupational Exposure to Crystalline Silica after reviewing the comments received in the fall.

By February 2020, OSHA announced a revision to the National Emphasis Program to identify and reduce or eliminate worker exposures to respirable crystalline silica in general industry, maritime and construction. According to the Administration, the NEP targets industries expected to have the highest numbers of workers exposed to silica and focuses on enforcement in of the new silica standards.

In order to pass the new NEP, the following changes were made:

  • Revised application to the lower permissible exposure limit for respirable crystalline silica to 50 micrograms per cubic meter (µg/m3) as an eight-hour time-weighted average in general industry, maritime and construction;
  • Updated list of target industries, as listed in the appendix of the NEP; from this list, area offices will develop randomized establishment lists of employers in their local jurisdictions for targeted inspections;
  • Compliance safety and health officers will refer to current enforcement guidance for RCS inspection procedures;
  • All OSHA regional and area offices must comply with this NEP, but they are not required to develop and implement corresponding regional or local emphasis programs; and
  • State plans must participate because of the nationwide exposures to silica.

Then, in April 2020, OSHA extended its National Emphasis Program Specifically, the NEP on respirable crystalline silica will look at industries in West Virginia, Delaware, Pennsylvania and the District of Columbia suspected of having an excess of workers exposed to silica. Additionally, the NEP will also focus on enforcement of two new silica standards, one for the general and maritime industries, and one for the construction industry.

Finally, in September of last year, OSHA launched a new initiative to protect workers from silica exposure in the stone fabrication and installation industry. The Respirable Crystalline Silica Focused Inspection Initiative focused on enforcement and providing compliance assistance.

Additionally, the initiative was anticipated to supplement the current National Emphasis Program for Respirable Crystalline Silica.

OSHA and the National Institute for Occupational Safety and Health identify silica dust exposure as a health hazard for workers involved in manufacturing, finishing and installing natural and manufactured stone, which includes the man-made, engineered artificial or cultured types.

When inhaled, very small crystalline silica particles expose workers to the risk of silicosis or other dangerous diseases.

According to OSHA’s release, a July 2023 study released by the American Medical Association highlighted dangers for workers, citing 52 male patients diagnosed with silicosis caused by occupational exposure to respirable silica dust from engineered stone. Of these patients, 20 suffered progressive massive fibrosis, 11 needed lung transplants and 10 died due to their exposures.

The initiative was expected to prioritize enforcement efforts on industry employers to make sure they're following required safety standards and providing workers with the protections required to keep them healthy. It also established procedures for federal OSHA inspections to identify and ensure prompt abatement of hazards in covered industries where workers face exposure to high levels of silica dust.


Tagged categories: Air quality; Certifications and standards; Department of Labor; Environmental Control; Environmental Controls; Environmental Protection; Government; Health & Safety; Health and safety; Mines; NA; North America; Program/Project Management; Regulations; Respiratory Protection Standard; Safety; Silica; Silica rule

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