Like many Californian’s, currently our districts are facing fires near and far that are creating air quality concerns. Due to the increase in frequency as well as severity of the fire’s in the California, in 2019 Cal/OSHA put out emergency regulation §5141.1. §5141.1 relates to all workplaces where workers will reasonably anticipate exposure to wildfire smoke and the Air Quality Index (AQI) of Particulate Matter 2.5 (PM2.5) is at or above 151. Employers can visit,, or their local Air Quality Management District to find the current AQI for PM2.5.

Once the AQI for PM2.5 is measured at or above 151, the employer is required to:

(1) Check the current AQI before and periodically during each shift.
(2) Provide training to employees.
(3) Lower employee exposures.
(4) Provide respirators and encourage their use.

PM2.5 is a fine particulate matter that has a size of 2.5 microns in diameter or smaller, which is equal to about 3% of the diameter of a human hair. Due to their size, PM2.5 are considered the most hazardous since they have the tendency to float in the air for long periods of time, while the heavier particulates such as PM10 will drop.

To view the full regulation from Cal/OSHA, including exemptions, please click here. If you have any questions about this ruling or how it relates to your district, don’t hesitate to reach out to our Loss Prevention Department.