Audit, Compliance and Risk Blog

OSHA Expands Regulation Of Crystalline Silica

Posted by Jon Elliott on Tue, Apr 12, 2016

Crystalline_Silica.jpgThe US Occupational Safety and Health Administration (OSHA) regulates thousands of chemicals, through regulatory standards directing employers to reduce worker exposures. At the broadest level, employers must evaluate basic information about every potentially hazardous chemical, and provide information to employees in compliance with OSHA's Hazard Communication Standard (I’ve blogged about changing HCS requirements here, and here). OSHA’s Air Contaminants Standard provides ambient workplace air limits for hundreds of listed contaminants. OSHA also provides more tailored requirements for classes of chemicals (such as flammables), and for types of activities that pose chemical hazards (such as welding). For a small number of especially hazardous chemicals, OSHA provides a detailed standard applicable to a single chemical—examples include asbestos, benzene, and lead. On March 25, 2016, OSHA established another single-chemical standard, for respirable crystalline silica (29 CFR section 1910.1053). Most affected employers must comply by June 23, 2018; a few provisions are phased in later, and construction employers must meet most requirements by June 23, 2017.

What’s So Bad About Crystalline Silica?

What hazards put crystalline silica into the elite handful of chemicals that warrant separate OSHA standards?

First, inhalation of very small crystalline silica particles risks silicosis, lung cancer, chronic obstructive pulmonary disease, and kidney disease (OSHA calculates 642 annual deaths and many thousands of severe illnesses). OSHA established permissible exposure limits (PELs) for crystalline silica in workplaces in 1971, among its first PEL rulemakings. The new rules tighten those limits for the first time, to reflect intervening decades of medical evidence.

Second, crystalline silica is used in a wide variety of workplaces, so many workers are exposed to these potential hazards (OSHA estimates 2.3 million workers are exposed). Respirable crystalline silica is created during work operations involving stone, rock, concrete, brick, block, mortar, and industrial sand. Exposures can occur when cutting, sawing, grinding, drilling, and crushing these materials. These exposures are common in brick, concrete, pottery manufacturing operations, foundries, sand blasting operations, and hydraulic fracturing (fracking) operations in the oil and gas industry.

What New Exposure Limits is OSHA Adopting?

OSHA’s Air Contaminants Standard (29 CFR 1910.1000) presents PELs for different forms of crystalline silica based on one or both of two alternative formulas, each based on 8 hour time weighted averages (TWAs) over a shift:

  • 250 million particles per cubic foot (mppcf) (particle-count formula)

  • 10 milligrams per cubic meter (mg/m3) (mass formula).

The standard instructs employers to divide results for cristobalite and tridymite by two, reflecting the mix of particle sizes generated by those varieties. OSHA is reaffirming these Air Contaminant Standard limits, adding a qualifier that they will apply if the tighter limits in the new Respirable Crystalline Silica Standard are stayed or inapplicable. The new Standard adopts the following PELs:

  • Action level 25 micrograms per cubic meter (μg/m3) (calculated as an 8-hour TWA)

  • PEL 50 μg /m3 (calculated as an 8-hour TWA).

How Will Employers Comply?

OSHA's new Respirable Crystalline Silica Rule follows the regulatory approaches used in other chemical-specific standards. It provides the following:

  • Establishes Action Level and PEL (as noted above).

  • Requires exposure assessment by employees who "are or may reasonably be expected to be" exposed to respirable crystalline silica at or above the Action Level, and notifications to affected employees. The Standard allows two basic assessment options:

    • Performance option - employer assesses 8 hour TWA for each employee, through an appropriate combination of air monitoring data and “objective data”.

    • Scheduled monitoring option – employer performs initial monitoring, and follow-up monitoring as specified in the Standard based on results.

  • Requires employers to define regulated areas where the PEL may be exceeded, and to limit access to designated employees (who must be provided with appropriate respiratory protection).

  • Specifies methods of compliance to reduce and manage hazards, including detailed requirements for:

    • Engineering and work practice controls (with the target of reducing exposures below the PEL).

    • Written exposure control plan covering tasks, engineering and work practice controls, respiratory protection, and housekeeping.

  • Respiratory protection, including training and use or appropriate respirators.

  • Housekeeping, which may include wet sweeping or use of high-efficiency particulate air (HEPA) filters.

  • Medical surveillance program covering affected employees.

  • Hazard communication to affected employees, in workplace signs and the employer’s HCS program.

  • Requirements to make and keep specified records of evaluations and compliance.

Self-Assessment Checklist

Does my organization include workplaces where employees may be exposed to respirable crystalline silica?

  • Have ambient concentrations in workplace air been measured?]

Has the organization confirmed whether each area with potential exposures meets the limits in the Air Contaminants Standard?

  • Does the employer already conduct monitoring and risk reduction activities?

Has the organization confirmed whether each area with potential exposures meets the limits in the new Respirable Crystalline Silica Standard?

  • If so, has the organization established a schedule to achieve compliance by applicable deadlines?

Where Can I Go For More Information?

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About the Author

jon_f_elliott.jpgJon Elliott is President of Touchstone Environmental and has been a major contributor to STP’s product range for over 25 years. He was involved in developing 12 existing products, including Environmental Compliance: A Simplified National Guide and The Complete Guide to Environmental Law.

Mr. Elliott has a diverse educational background. In addition to his Juris Doctor (University of California, Boalt Hall School of Law, 1981), he holds a Master of Public Policy (Goldman School of Public Policy [GSPP], UC Berkeley, 1980), and a Bachelor of Science in Mechanical Engineering (Princeton University, 1977).

Mr. Elliott is active in professional and community organizations. In addition, he is a past chairman of the Board of Directors of the GSPP Alumni Association, and past member of the Executive Committee of the State Bar of California's Environmental Law Section (including past chair of its Legislative Committee).

You may contact Mr. Elliott directly at:

photo credit: 20100827_infraredTesting001 via photopin (license)

Tags: Health & Safety, OSHA, EHS, Hazcom