Respirable Crystalline Silica Standards

Important Update

This webpage gives an overview of new standards to control employee exposures to respirable crystalline silica, which can cause silicosis, lung cancer, and other serious health effects.

The standards are found in the following sections of the California Code of Regulations, title 8:

To access a table of contents and search engine, go to Cal/OSHA Title 8 Regulations Table of Contents.

Section 5155 requires all employers to protect employees from exposures that exceed the "permissible exposure limit" (PEL) for respirable crystalline silica. NOTE: Construction employers and certain other employers properly using exposure control methods provided in Table 1 of section 1532.3 for particular construction tasks are not required to verify that employee exposures are at or below the PEL.

Section 1532.3 applies to occupational exposures in construction, except where exposures will remain below the "action level" under any foreseeable conditions.

Section 5204 apples to all occupational exposures except construction work, agricultural operations, and exposures from the processing of sorptive clays. In addition, section 5204 does not apply in the following situations:

  • The employer demonstrates (through methods specified in section 5204) that exposures will remain below the "action level" under any foreseeable conditions; or
  • The employer complies with section 1532.3 (as specified in section 5204, for tasks not performed regularly).

The PEL for respirable crystalline silica is 50 micrograms per cubic meter (µg/M3) of air. This is the maximum concentration of respirable crystalline silica in air, as an eight-hour time-weighted average, to which an employee may be exposed.

The action level for respirable crystalline silica is 25 micrograms per cubic meter (µg/M3) of air. This is the concentration of respirable crystalline silica in air, as an eight-hour time-weighted average, at or above which employers must assess employee exposures, as prescribed in sections 1532.3 and 5204, and conduct medical surveillance, as prescribed in section 5204.

The broad categories of requirements are as follows:

Broad Categories of Requirements Section 1532.3 Section 5204
Methods of exposure control or compliance 1532.3(c) or (d)(3) 5204(a)(3) or (f)
Exposure assessments 1532.3(d)(2) 5204(d)
Respiratory protection 1532.3(e) 5204(g)
Housekeeping 1532.3(f) 5204(h)
Restricted or regulated areas 1532.3(g)(1)(D) 5204(e)
Written exposure control plans 1532.3(g) 5204(f)(2)
Medical surveillance 1532.3(h) 5204(i)
Communication of respirable crystalline silica hazards to employees 1532.3(i) 5204(j)
Recordkeeping 1532.3(j) 5204(k)

In general, the requirements in section 1532.3 are more protective than most of the requirements in section 1530.1. However, section 1530.1 contains certain requirements not found in section 1532.3. Construction employers covered by section 1530.1 must still comply with those requirements, found in the following subsections:

  • Subsection 1530.1(d)(1) requires procedures to ensure that dust reduction systems maintain their effectiveness for dust reduction throughout the work shift.
  • Subsection 1530.1(e) contains additional training topics, not included in section 1532.3, for employers and supervisors.

The PEL for respirable crystalline silica (50 micrograms per cubic meter (µg/M3) of air) is currently in effect. Employers not using exposure control methods provided in Table 1 of section 1532.3 for particular construction tasks must ensure that employee exposures are at or below the PEL.

Section 1532.3 is currently in effect, except as follows:

  • Requirements for methods of sample analysis in subsection 1532.3(d)(2)(E) and Appendix A go into effect on June 23, 2018.

Section 5204 goes into effect on June 23, 2018, except as follows:

  • Medical surveillance requirements in subsection 5204(i)(1)(A) go into effect on the following dates:
    • June 23, 2018, for employees who will be exposed to respirable crystalline silica above the PEL for 30 or more days per year.
    • June 23, 2020, for employees who will be exposed to respirable crystalline silica at or above the action level for 30 or more days per year.
  • For hydraulic fracturing operations in the oil and gas industry, requirements for engineering controls in subsection 5204(f)(1) go into effect on June 23, 2021.

Revised May 22, 2018