On August 23, 2013, the Occupational Safety and Health Administration (OSHA) released its long-awaited proposal to considerably toughen its regulation of respirable crystalline silica—the most common form of which is quartz.  Crystalline silica is a natural constituent of the earth’s crust and the most common constituent of  sand.  Silica is used throughout U.S. industry, including in foundries, and in the manufacture of glass, plastics, roofing materials, paintings and coatings, and concrete products.  It is used in fracking and in concrete construction and demolition.  In short, crystalline silica is ubiquitous in nature and industry. 

In most industries, OSHA is proposing to halve the daily permissible exposure limit (PEL), from about 100 µg (micrograms)/M³ to 50 µg/M³.  In construction, OSHA is proposing to lower the limit from about 250 µg/M³ to 50 µg/M³. 

To reduce worker exposure to or below the reduced PEL, the proposed rule would require implementing engineering and work practice controls, including exposure assessments and monitoring, establishment of regulated areas or controlled access areas, respiratory protection programs, employee training and information, and medical surveillance of employees over-exposed for 30 or more days annually.  Information, training and recordkeeping requirements would also be imposed.

Employers would not be permitted to rely on respirators except to the extent that the employer shows that engineering and work practice controls are infeasible.  Employee rotation as a control method would be prohibited.

OSHA’s justification for the reductions in the PELs—that workers face a significant risk to their health at the current limits—is expected to be the most controversial aspect of the rulemaking.  Many companies and trade associations believe that a reduction is unjustified, and that the proposed permissible exposure levels are infeasible.

The proposed standard will be published in the Federal Register.  Rulemaking comments will be due within 90 days from date of formal publication in the Federal Register.  Those who wish to testify or question hearing witnesses must submit a notice of intent to OSHA within 60 days from Federal Register publication.

Additional Resources

View the August 23 Notice of Proposed Rulemaking.

View health effects & risk assessment background documents.

View preliminary economic analysis and employment analysis.

View the federal docket for silica rulemaking.