Crystalline Silica

Worker Safety

Employers must control dust exposures and ensure they remain below the Occupational Safety and Health Administration’s (OSHA’s) permissible exposure limit (PEL)external icon of 50 µg/m3 (micrograms of silica per cubic meter of air) as an 8-hour time weighted average (TWA) by implementing effective engineering controls and safe work practices. Additionally, OSHA requires that employers offer certain protections, such as environmental sampling and medical exams, when respirable crystalline silica levels meet or exceed the OSHA action level of 25 µg/m3.

Employers should reference the federal OSHA Respirable Crystalline Silica webpageexternal icon for more information on the final silica rule, requirements for employers, and specific implementation dates. Additionally, employers within states that have an OSHA-approved state planexternal icon should follow the applicable standards.

LW shearer operator sprays the walls of mine to extract coal.

Photo by NIOSH

Protections to Use When Working Around Silica Dust
  • Assure that workers follow dust control methods found in the OSHA compliance guides for the construction industrypdf icon and general industry and maritime.pdf icon
  • Use wet methods that apply water at the impact site where dust is generated.
  • Remove silica dust using local exhaust ventilation at the point where dust is made.
  • Isolate the work process using enclosures.
  • Use a combination of both water and ventilation controls, if proven effective.
  • Ensure that all engineering controls are working properly and replace water and air filters as necessary to control dust.
  • Implement regular and thorough housekeeping procedures. Avoid dry sweeping or using compressed air.
  • Use respiratory protection when dust controls and safe work practices cannot limit silica exposures below the Occupational Safety and Health Administration’s Permissible Exposure Limit (PEL).
Silica Medical Surveillance Program
  • Develop and implement a written exposure control plan.
  • Implement housekeeping practices that do not increase employee exposure to crystalline silica.
  • Offer medical exams as required by OSHA.
  • Provide worker training about the hazards of silica exposure, tasks where exposures can occur, and ways to limit exposure.
  • Keep records of silica exposure and medical exams for workers.
Page last reviewed: October 16, 2019