Proposed Occupational Exposure to Respirable Crystalline Silica – September 2013

The United States Department of Labor’s Occupational Safety and Health Administration announced a Notice of Proposed Rulemaking for Occupational Exposure to Respirable Crystalline Silica on August 23, 2013.  The document proposes methods to reduce lung cancer, silicosis, chronic obstructive pulmonary disease and kidney disease in American workers.  A new permissible exposure limit for respirable crystalline silica of 0.05 mg/mᵌ is proposed with an action level of 0.025 mg/mᵌ. This action level matches the Threshold Limit Value recommended by the American Conference of Governmental Industrial Hygienists.  The proposed rule also includes requirements for controlling worker exposures, conducting medical surveillance, training workers about silica-related hazards, and recordkeeping.

Following the publication of the proposed rule, a public hearing will begin on March 4, 2014 in Washington, D.C. in the auditorium of the U.S. Department of Labor.

OSHA estimates that once the full effects of the ruling are realized, its requirements could save nearly 700 lives and prevent 1,600 new cases of silicosis annually.


Abstract Summary

General Industry (1910.1053)

  • The proposed general industry standard is structured and worded similar to other substance-specific standards (asbestos, lead, hex chrome). It contains sections on exposure assessment, regulated areas, hazard communication, training, medical surveillance, recordkeeping, engineering controls, and respirators.
  • Exposure limits:
    • Action level of 0.025 mg/m3 (respirable). This is the same as the current ACGIH TLV.
    • PEL of 0.05 mg/m3 (respirable).
  • An initial exposure assessment is required where exposures are “reasonably expected to exceed the action level.” Objective data (e.g., industry-wide study rather than actual jobsite monitoring) can be used to determine exposures instead of air sampling in the actual workplace. However, the data “must reflect workplace conditions closely resembling the processes, types of material, control methods, work practices, and environmental conditions in the employer’s current operations.” If actual workplace air monitoring data are used for the initial assessment, the data must have been collected within the past 12 months.
  • Periodic repeat monitoring (every 3-6 months) is required if initial exposures exceed the action level or PEL.
  • Exposures above the PEL trigger establishing a regulated area, engineering controls, respirators, medical surveillance, work practices, and a written plan. Use of compressed air and dry sweeping are prohibited for cleaning.
  • Medical Surveillance is triggered by exposure above the PEL for 30-days/year. An exam must be made available to employees, and include a chest x-ray, pulmonary function test, and latent TB infection test. The exam must be repeated every 3 years.
  • There are some detailed laboratory analysis requirements. It may take labs some time to get up to speed.
  • Requirements phase in over a one-year period after the final standard is published.


Construction (1926.1053)

  • The proposed construction standard contains many of the same requirements as the General Industry standard. Exposure assessment requirements are the same, except for a list of specific operations (see next bullet).
  • The proposed standard contains a list of 13 specific operations for which you must use engineering controls, work practices, and respirators. Where a respirator is required, you must assume exposures exceed the PEL and implement other sections of the standard triggered by the PEL. Examples include:
    • Use of a stationary masonry saw- must use a water system. Must wear a respirator if done for more than 4-hours per day.
    • Hand grinding – must use a water system or LEV shroud. Must wear a respirator depending on the type of control and length of operation per day.
    • Drywall finishing – must use a dust collection system and a respirator, or use wet sanding. A respirator is not required for wet sanding.

Abrasive blasting is not listed in the table of specific operations.  However, the proposed silica standard refers to 29CFR§1926.57(f), which is an existing OSHA regulation on ventilation, with specific requirements for abrasive blasting.



OSHA News Release – Protect Workers Exposure to Crystalline Silica

OSHA NPRM for Occupational Exposure to Respirable Crystalline Silica (PDF)

Colden professionals have the tools necessary to create best-in-practice health and safety programs to optimize workers’ productivity and reduce health and safety risks in the oil and gas extraction industry.



Christopher J. Wesley, CIH