Construction Industry, Concrete Makers* Subject to New Silica Dust Rules

The federal Occupational Safety and Health Administration (OSHA) promulgated regulations limiting worker exposure levels to respirable crystalline silica to 50 micrograms per cubic meter of air for an eight-hour shift and providing other safeguards to protect workers. How are the federal amendments going to affect California’s construction industry and fixed location manufacturers of concrete products?

On March 25, 2016, federal OSHA published a final rule written as two standards, one for construction and the other for general industry and maritime. The regulations lower the permissible exposure limit (PEL) for crystalline silica to 50 micrograms per cubic meter of air, averaged over an eight-hour shift.

The Construction Safety Orders (CSO) has a new Section 1532.3 and the General Industry Safety Orders (GISO) has a new Section 5204 and revised Section 5155.

The Cal/OSHA Standards Board adopted the federal regulation and submitted the regulation with modifications to fit California’s regulatory format to the Office of Administrative Law. The state regulation was approved on October 17, 2017 and is now effective for the construction industry. The GISO regulations become fully effective on June 23, 2018.

Common Requirements

Common requirements for both construction and industry are:

• Establish and implement a written exposure control plan (WECP) that identifies hazards and methods used to protect workers. Include procedures restricting access to work areas where high exposures may occur.

• Designate a competent person to implement the WECP.

• Restrict housekeeping practices that expose workers to silica where feasible alternatives are available.

• Provide respirators to workers when dust controls cannot limit exposures above the PEL.

• Offer medical exams, including X-rays and lung function tests, every three years for workers who are required by the regulation to wear a respirator for 30 days or more per year.

• Train workers on work operations that result in silica exposure and ways to limit exposure.

• Keep records of exposure measurements, objective data, and medical exams.


Each of the regulations contains identical appendices:

• Appendix A is mandatory and provides methods of sample analysis to employers in accordance with the new regulation.

• Appendix B is nonmandatory and provides medical surveillance guidelines to employers.

Because construction results in an ever-changing environment, a table has been developed for common respirable crystalline silica-producing activities. The table is divided into exposures of less than 4 hours and for exposures of more than 4 hours.

The dust-mitigating process is included with each process and tool. Mitigation may be equipment with a dust collector, integrated water delivery system, a combination of devices, or the employee will be required to wear a respirator.

Because the processes in general industry can be limited or contained in specific areas, the general industry regulation is directed more toward proving silica exposures are occurring below certain levels; therefore, the emphasis is on testing/sampling. The action level is 25 micrograms per cubic meter of air averaged over an eight-hour day.

Regulation Text

The full text of the regulations can be found on the Occupational Safety and Health Standards Board website,, under approved standards. Also,, federal OSHA’s website, has material to assist employers in complying with the regulation.

*Manufacturers of concrete products where respirable silica is incorporated in the manufacturing process.

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Staff Contact: Mel Davis