Crystalline Silica

Worker Information

Crystalline silica is a natural component of stone, soil, and sand. It is also found in other materials such as concrete, mortar, granite, and artificial stone. The most common form of crystalline silica is quartz. If you work around these products, you could be exposed. Cutting, drilling, chipping, sanding, or grinding materials that contain crystalline silica can release hazardous levels of respirable dust in the air that workers breathe.

To prevent exposures, control dust by following safe work practices and using engineering controls (strategies used to modify equipment or a process to protect workers from hazards).

man wearing respirator cutting granite countertop

A stone countertop worker grinding a countertop wearing personal protective equipment and using engineering controls (sheet-water-wetting) to minimize silica dust exposure.

Engineering Controls and Safe Work Practices
  • Follow dust control methods found in the Occupational Safety and Health Administration (OSHA) compliance guides for the construction industry and general industry and maritime. Dust control methods for mining can be found in the NIOSH Mining Program Report of Investigation: Dust Control Handbook for Industrial Minerals Mining and Processing – Second Edition.
  • 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.
  • Use enclosures when available to isolate the work process.
  • Consider using a combination of both water and ventilation controls.
  • Ensure that all engineering controls are working properly prior to use and replace water and air filters as necessary to control dust.
  • Avoid dry sweeping or using compressed air during regular and thorough housekeeping procedures.
  • 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).
  • Participate in a medical monitoring program when an employer has shown crystalline silica levels are above occupational exposure limits.
  • Research methods for engineering controls of various tasks.

The NIOSH Health Hazard Evaluation (HHE) Program provides free assistance and information on workplace exposures and employee health. Employees, union officials, or employers concerned about exposures in the workplace can request an evaluation of possible health hazards, including silica, at their workplace.