Air Quality Index (AQI) Event for airborne particulate matter (PM) 2.5 is 151 or greater

Past years lead to the most destructive fire seasons in California’s history — over 7,600 wildfires burned two million acres. As a result, the California Department of Industrial Relations (DIR) Occupational Safety Health Standards Board (OSHSB) adopted an emergency regulation to protect workers from hazards associated with wildfire smoke. The regulation is by the California Office of Administrative Law.

The emergency regulation applies where the current Air Quality Index (AQI) for airborne particulate matter (PM) 2.5 is 151 or greater (the AQI scale is from 0 to 500, and a 151 AQI is considered “unhealthy”), or where employers reasonably anticipate that employees can be exposed to wildfire smoke.

Further, the emergency regulation exempts worksites that are indoors and where the air is filtered by mechanical ventilation. It also exempts outdoor worksites where the employer can demonstrate that the AQI level does not exceed 151, or where the AQI level is 151 or greater for one hour or less during a shift. Firefighters are also exempt.

California employers must determine employee exposure to PM 2.5 for worksites covered by this section before each shift and periodically thereafter by:

  • Checking state and government websites to determine the current AQI for PM;
  • Obtaining AQI forecasts and the current AQI for PM directly from the Environmental Protection Agency or state or local agencies, and;
  • Measuring PM 2.5 levels at the worksite and converting the PM 2.5 levels to the corresponding AQI.

After determining employee exposure, employers are responsible for communicating to at-risk employees the current AQI level for PM 2.5 and providing protective measures available to employees to reduce wildfire smoke exposure. Employers must also provide training or relevant information about smoke exposure to at-risk employees.

If an employer discovers the AQI is above 151, it must implement controls to reduce employee exposure. This includes, but is not limited to, providing respiratory protection or administrative controls, including relocating work to a location where the current AQI for PM 2.5 is lower than 151, changing work schedules, reducing work intensity, or providing additional rest breaks.

(Sources: ISHN Magazine and The National Law Review

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