The photograph shows a worker sandblasting an exterior concrete surface. 

A worker sandblasts a concrete surface.

Crystalline Silica Rule Under Review at the Office of Management and Budget
Thomas Harman, Portland Cement Association, and Tony Kojundic, Elkem Materials Inc.

In February 2011, the Occupational Safety and Health Administration (OSHA) sent its proposal to manage occupational exposure to respirable crystalline silica (RCS) in the workplace to the Office of Management and Budget (OMB) for review prior to publication. After an initial ninety-day period, OMB extended its review, and the proposal has remained at OMB since. Worker exposure to RCS has been on OSHA’s agenda for some time. The report from the Small Business Administration, which is referred to as the SBREFA Panel report (Small Business Regulatory Enforcement Fairness Act of 1996), published findings about the effects on small businesses in December 2003. The peer review report to assess health effects of RCS on humans was initiated in May 2009 and completed in January 2010.

OMB has met with several stakeholders, including trade associations, labor organizations, and individual companies during the review process in order to gather information about how a RCS rule would affect the groups. For example, the Portland Cement Association (PCA) led a coalition of trade associations that represented concrete product manufacturers, including the National Ready Mixed Concrete Association, the Precast/Prestressed Concrete Institute, the National Concrete Masonry Association, and the American Concrete Pipe Association, to communicate to OMB their collective interests in the proposal. The meeting took place in May 2011.

OSHA is believed to be considering three permissible exposure limits (PEL) for exposure to crystalline silica in the proposal* : 0.1mg/m³, 0.05 mg/m³, and 0.025 mg/m³. The currently enforceable limit from OSHA is 0.1mg/m³. In addition to revising the PEL and in consideration of other comprehensively managed health standards like those found in Title 29 Code of Federal Regulations Part 1910 Subpart Z (29 CFR 1910), the agency may also promulgate requirements for ancillary provisions. The elements contained in ancillary provisions may include:

• Personal monitoring (in addition to area monitoring) for exposure to crystalline silica;
• The establishment of regulated areas;
• The designation of a competent person to conduct exposure assessments;
• Banning certain practices in the workplace;
• Specific provisions related to abrasive blasting work;
• Respiratory protection and other personal protective equipment, such as coveralls;
• Personal hygiene and shower facilities;
• Meal rooms where materials contaminated with RCS may not be present;
• Special housekeeping practices and requirements;
• Individual health screening and employee health monitoring;
• Special provisions for hazard communication; and
• Requirements for individual recordkeeping

Companies must take a most cautious approach in protecting their employees’ health if employees are potentially exposed to crystalline silica at work. Various federal, state and sometimes local standards mandate RCS exposure testing to determine the level of the material in the workplace. Industrial hygienists are trained professionals who test the work atmosphere to detect the presence of harmful or noxious contaminants, such as respirable crystalline silica, to which individuals are exposed. Testing for the presence of RCS involves the use of an air sampling pump over a designated period of time. The pump collects air from the individual’s breathing zone, and deposits the respirable portion of CS dust onto a filter which has been pre-weighed. The difference between the pre-sample and post-sample weight allows an analytical laboratory to determine the amount of RCS to which the employee is exposed. If an overexposure to RCS is detected, then companies must determine the appropriate method to reduce the overexposure. Controlling the exposure risk to RCS may include:

• Eliminating the hazard by substituting another material for respirable crystalline silica, or
• Revising the process that uses RCS by introducing a high-efficiency particulate air (HEPA) filter, or
• Reducing the amount of time that the employee is exposed to RCS, or
• Requiring the employee to wear a personal air respirator

Eliminating the respiratory hazard is always preferable to requiring the use of personal protective equipment.

At this time, only the officials at OMB know if/when the agency plans to send the proposal back to OSHA, either allowing publication to go forward without revision, or requiring OSHA to revise the standard before the agency can formally issue a Notice of Proposed Rulemaking (NPRM). In the Unified Agenda from the Department of Labor, OSHA shows an NPRM on crystalline silica will be released in May 2013. The rule is “economically significant,” which means that the rule could have an annual effect of $100 million or more on the economy, or that the rule could “adversely affect the economy, productivity, competition, jobs, the environment, public health and safety, or tribal governments or communities.”

Associations like the Silica Fume Association, ( the Portland Cement Association, ( and those previously noted in the article provide excellent guidance and resources for managing respirable crystalline silica in the workplace. Regardless of the administrative status of the rule, employee exposures to RCS must still be controlled.


1. Centers for Disease Control and Prevention, NIOSH Pocket Guide to Chemical Hazards, April 4, 2011

2. Portland Cement Association, The Cement Plant Industrial Hygiene Handbook, 1983

3. Silica Fume Association, The Silica Fume User’s Manual, April, 2005

4. Small Business Administration, Office of Advocacy, Report of the Small Business Advocacy Review Panel On the Draft OSHA Standards for Silica, December 19, 2003

5. United States Department of Labor, Occupational Safety and Health Administration, Title 29 Code of Federal Regulations Part 1910

The photograph shows a worker sandblasting an exterior concrete surface.