Employer’s Guide to the Revised Respirable Crystalline Silica Standard



In response to changes by federal OSHA to its standard on respirable crystalline silica, the Cal/OSHA Standards Board adopted those changes with little variation.  The California standard became effective and enforceable on October 23, 2017.


  • Reduction of the Permissible Exposure Limit (PEL) from 100 µ/M³ to 50 µ/M³ over an 8-hour time weighted average
  • A requirement for engineering controls (such as water or ventilation) to limit worker exposures
  • Limiting worker exposure to high exposure areas
  • Development of a written exposure control plan
  • Restrict housekeeping activities that may expose workers to respirable silica
  • Provision of respirators to workers when engineering controls do not limit respirable silica below the required levels
  • Offering medical exams to highly exposed workers, and training workers on silica risks and how to limit exposures


The revised standard includes Table 1 – “Specified Exposure Control Methods When Working with Materials Containing Crystalline Silica”. For employers engaged in tasks identified in Table 1, the employer shall fully and properly implement the engineering controls, work practices, and respiratory protection specified in Table 1.

For these eighteen (18) tasks, Engineering and Work Practice Control Methods are described.  Also included is the Required Respiratory Protection and Minimum Assigned Protection Factors (APF) for work shifts ≤4 hours and >4hours.


  1. Scope and Application – the standard applies to all occupational exposures except where exposures remain below 25 micrograms per cubic meter of air as an 8-hour time weighted average
  2. Definitions – of particular note are the definitions of “competent person” and “objective data”
  3. Specified Exposure Control Methods – this subsection contains Table 1 as described above
  4. Alternative exposure control methods – if an employer does not utilize Table 1, there are two options for ensuring that no employees are exposed to silica in excess of 50 µ/M³. 1) Performance option – the employer can assess exposures on the basis of any combination of air monitoring data or objective data sufficient to characterize employee exposures; or, 2) Scheduled monitoring option – the employer must undertake initial monitoring to assess exposures.
  5. Respiratory Protection – where respiratory protection is required, the employer must provide each employee an appropriate respirator that complies with this subsection and Section 5144 (respiratory protection).
  6. Housekeeping – dry sweeping or dry brushing is not permitted unless wet sweeping, HEPA-filtered vacuuming or other methods are not feasible. Compressed air shall not be used unless the compressed air is in conjunction with a ventilation system that effectively captures the dust cloud created by the compressed air; or no alternative method is feasible
  7. Written Exposure Control Plan – following are the minimum requirements:
    1. A description of the tasks in the workplace that involve exposure to respirable crystalline silica
    2. A description of the engineering controls, work practices, and respiratory protection used to limit employee exposure to silica for each task
  • A description of the housekeeping measures used to limit employee exposure to respirable crystalline silica
  1. A description of the procedures to restrict access to work areas, when necessary, to minimize the number of employees exposed to silica and their level of exposure, including exposures generated by other employers or sole proprietors
  2. The plan must be reviewed and evaluated at least annually and updated as necessary
  3. The plan should be readily available at no cost to each employee covered, their designated representatives, or representatives of Cal/OSHA
  • A designated “competent person” shall make frequent and regular inspections of job sites, materials, and equipment to implement the plan
  1. Medical Surveillance – the employer shall make medical surveillance available at no cost to the employee, and at a reasonable time and place, for each employee who will be required to use a respirator for 30 or more days each year. Specific requirements can be found in the standard.
  2. Communication of respirable crystalline silica to employees – the employer shall include respirable crystalline silica in the program to comply with the Hazard Communication Standard (HCS) (Section 5194). Training for employees shall include the following hazards:  cancer, lung effects, immune system effects, and kidney effects.  Employers must ensure that each employee covered by this section can demonstrate knowledge and understanding of:
    1. Health hazards associated with exposure to silica
    2. Specific tasks in the workplace that could result in exposure to silica
  • Specific measures the employer has implemented to protect workers from exposure including engineering controls, work practices, and respirators
  1. The contents of this section on communications
  2. The identity of the competent person
  3. The purpose and a description of the medical surveillance program
  1. Recordkeeping – The employer shall make and maintain an accurate record of all exposure measurements taken to include
    1. Air monitoring data
    2. Objective data
  • Medical Surveillance
  1. Dates – The standard is in effect and fully enforceable.


The following links provide additional information and assistance:

This link provides helpful information on:  1) creating a plan, 2) silica hazard alert card information for workers, and, 3) toolbox talk bullet points

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