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MIOSHA Launches a State Emphasis Program for Respirable Crystalline Silica

Crystalline silica is a common and naturally-occurring material that is found in sand, concrete, brick, block, natural stone and mortar. Inhalation of respirable crystalline silica (RCS) can cause silicosis. Silicosis is an incurable lung disease that impairs a person’s ability to take a full breath due to scarring of the lungs. Silicosis can progress even after a person is no longer exposed to the dust, causing severe shortness of breath many years later. The science available supports the correlation between exposure time and risk; essentially, the longer the exposure to the dust, the greater the risk of developing silicosis. Because there is no effective treatment for silicosis, prevention through exposure control is essential to preventing silicosis.

Crystalline silica is quartz and cristobalite dust occurring in industrial and occupational settings in the form of fine, breathable particles. These fine particles are 100 times smaller than ordinary sand found on beaches. About 20 years ago, Crystalline silica of respirable size was designated by OSHA as a known human carcinogen due to increased lung cancer rates in workers exposed to RCS.

This is important to the agency because nationally, over two million workers are exposed to RCS generated at workplaces by operations like cutting, sawing, grinding, spraying or when abrasive blasting with sand. OSHA has two standards for RCS: one for general industry and one for construction. These standards limit the amount of RCS that workers may be exposed and require employers to take immediate action to protect their employees.

To further protect workers, MIOSHA issued a State Emphasis Program (SEP) for RCS. Affected industries include:

  • Construction;

  • Concrete manufacturing;

  • Foundries;

  • and many more.

MIOSHA has gone as far as creating a list of workplaces most likely to have employees exposed to RCS. Businesses on the list can expect an inspection to ensure compliance with the standards. The investigations are unannounced and conducted by MIOSHA’s enforcement divisions. If the investigation reveals conditions that are not in compliance with regulations, citations will be issued that will almost certainly carry monetary penalties.

What should companies do to address this new enforcement emphasis?

First, the inventory of materials used at your facility must be reviewed to identify if any materials that employees use contain either quartz or cristobalite. If these materials are present at your facility, then monitoring needs to be conducted to determine the employee exposure levels. The alternative would be to let MIOSHA perform the monitoring with the hopes that employees are not overexposed, and monetary penalties are avoided. Note that the exposure limit of respirable crystalline silica is a scant 50 micrograms per cubic meter (50 ug/m3) or equivalently, 0.05 mg/m3.

CFR Environmental has been conducting indoor air quality studies for over 20 years, including monitoring for RCS. If your facility has RCS present, please contact CFR for consultation on how to navigate the RCS requirements.


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