California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 7 - General Industry Safety Orders
Group 16 - Control of Hazardous Substances
Article 107 - Dusts, Fumes, Mists, Vapors and Gases
Appendix A to Section 5141.1 - Protection from Wildfire Smoke Measuring PM2.5 Levels at the Worksite (Mandatory if an Employer Monitors with a Direct Reading Instrument)

(a) An employer may use a direct-reading particulate monitor to determine PM2.5 levels for section 5141.1, if the employer can demonstrate that it has complied with this appendix and selected a monitor that:

(1) Does not underestimate employee exposures to wildfire smoke; or

(2) May underestimate wildfire smoke exposures, but the employer has obtained information on the possible error of the monitor from the manufacturer and has accounted for the error of the monitor when determining exposures to PM2.5 to ensure that employee exposure levels are not underestimated.

(b) The monitor shall be designed and manufactured to measure the concentration of airborne particle sizes ranging from an aerodynamic diameter of 0.3 micrometers or less up to and including 2.5 micrometers ([LESS THAN EQUAL TO]0.3[MICRO]m to 2.5[MICRO]m).

(c) The employer shall ensure that the monitor and all necessary monitor accessories are calibrated, maintained, and used, in accordance with the manufacturer's instructions for accurately measuring particles with an aerodynamic diameter of 0.3 micrometers or less up to and including 2.5 micrometers ([LESS THAN EQUAL TO]0.3[MICRO]m to 2.5[MICRO]m). The employer may use an air monitor that measures particles less than 0.3 micrometers to greater than 2.5 micrometers ([LESS THAN EQUAL TO]0.3[MICRO]m to >=2.5[MICRO]m) if the employer treats the result as the PM2.5 level.

(d) The employer shall use the following table to convert the PM2.5 concentration to the AQI for PM2.5.

(e) The person supervising, directing, or evaluating workplace monitoring for PM2.5 shall have the training or experience necessary to apply this section and to ensure the correct use of the monitor and the interpretation of the results, so that exposures are not underestimated.

1. New Appendix A filed 7-29-2019 as an emergency; operative 7-29-2019 (Register 2019, No. 31). A Certificate of Compliance must be transmitted to OAL by 1-27-2020 or emergency language will be repealed by operation of law on the following day.
2. New Appendix A refiled 1-16-2020 as an emergency; operative 1-24-2020 pursuant to Government Code section 11346.1(d) (Register 2020, No. 3). A Certificate of Compliance must be transmitted to OAL by 4-23-2020 or emergency language will be repealed by operation of law on the following day.
3. New Appendix A refiled 4-30-2020 as an emergency; operative 6-23-2020 pursuant to Government Code section 11346.1(d) (Register 2020, No. 18). A Certificate of Compliance must be transmitted to OAL by 9-21-2020 or emergency language will be repealed by operation of law on the following day.
4. Emergency filed 4-30-2020 and operative 6-23-2020 extended 60 days pursuant to Executive Order N-40-20 and an additional 60 days pursuant to Executive Order N-66-20. A Certificate of Compliance must be transmitted to OAL by 1-19-2021 or emergency language will be repealed by operation of law on the following day.
5. Certificate of Compliance as to 4-30-2020 order, including amendment of Appendix A, transmitted to OAL 12-17-2020 and filed 2-1-2021; amendments operative 2-1-2021 pursuant to Government Code section 11343.4(b)(3) (Register 2021, No. 6).

Note: Authority cited: Section 142.3, Labor Code. Reference: Sections 142.3 and 144.6, Labor Code.