Silica Safe Work Practices
The most common form of crystalline silica is quartz. Silica is also found in other materials such as concrete, mortar, granite, and artificial stone. Prevent exposures and control dust when working around these materials. Follow safe work practices and use engineering controls (strategies to modify equipment or a process to protect workers from hazards).
- Follow dust control methods found in:
- Ensure that all engineering controls are working properly before using.
- Use wet methods that apply water to dusty areas.
- Use local exhaust ventilation where work is dusty.
- Use enclosures, when available, to isolate work processes.
- Consider combining water and ventilation controls.
- Replace water and air filters when needed or per manufacturer’s instructions.
- Avoid dry sweeping or using compressed air during housekeeping procedures.
- Use respiratory protection when dust controls and safe work practices cannot limit exposures below the OSHA permissible exposure limit (PEL).
- Participate in a medical monitoring program when crystalline silica levels are above exposure limits.
- Research methods for engineering controls of various tasks.
Under the OSHA Respirable Crystalline Silica Rule, employers are responsible for a range of measures to ensure that workers are protected from silica.
Measures include controlling dust levels below the permissible exposure limit (PEL) of 50 µg/m3 (micrograms of silica per cubic meter of air) as an 8-hour time weighted average (TWA). This is believed to be the maximum daily concentration that workers can be exposed to for a working lifetime without adverse health effects.
High levels of respirable silica dust can also be released by the mineral quartz during extraction, transport, and processing at mining operations. To protect exposure to mine workers, the current Mine Safety and Health Administration (MSHA) PEL for respirable quartz is 100 µg/m3, but a proposed rule would lower it to the same PEL that is used by OSHA.
Controlling dust levels can be accomplished by implementing effective engineering controls, such as:
- Local exhaust ventilation to capture dust
- Water sprays to suppress dust
Employers should reference the OSHA Respirable Crystalline Silica webpage for more information on requirements for employers, and specific implementation dates. Additionally, employers within states that have an OSHA-approved state plan should follow the applicable standards. Mining operators can go to the NIOSH Mining webpage for silica-related requirements and safe mining guidance.
- 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.