Cal/OSHA Adopts Emergency Wildfire Smoke Regulation Effective July 29, 2019

The Cal/OSHA Standards Board has approved the emergency protection of workers exposed to wildfire smoke regulation, effective July 29, 2019.  This standard applies to workplaces where the current Air Quality Index (AQI) of particulate matter reaches 151 or greater and where employers should reasonably anticipate that employees could be exposed to wildfire smoke.

For non-exempted employers (see below for a list of exempt worksites), the following steps must be taken to mitigate workers’ exposure:

  • Identify harmful PM from wildfire smoke before each shift and periodically thereafter by checking the AQI for P 2.5;
  • Reduce the exposure by relocating an enclosed building with filtered air or to another outdoor location where the AQI for M 2.5 is less than 150.

If you cannot move workers out of the affected area, then you must provide:

  • Respirators, such as N95 masks, for voluntary use;
  • Training on the new regulations, the health effects of wildfire smoke, and the safe use and maintenance of respirators.

It is important to remember that while it is the decision of the employee to use a respirator, employers must always make them available and ensure workers are trained in how to properly use them.  If the employee opts to not wear the mask, it is recommended that he/she signs documentation acknowledging that training was provided and the protection was offered and that it was his/her decision not to use the personal protective equipment.

The following workplaces are exempt from the regulation:

  • Enclosed buildings or structures in which the air is filtered by a mechanical ventilation system and the employer ensures that windows, doors, bays, and other openings are kept closed to minimize contamination by outdoor or unfiltered air;
  • Enclosed vehicles in which the air is filtered by a cabin air filter and the employer ensures that windows, doors, and other openings are kept closed to minimize contamination by outdoor unfiltered air;
  • The employer demonstrates that the concentration of PM 2.5 in the air does not exceed a concentration that corresponds to a current AQI of 151 or greater by measuring PM 2.5 levels at the worksite;
  • Employees exposed to a current AQUI for ON 2.5 of 151 or greater for a total of one hour or less during a shift;
  • Firefighters engaged in wildland firefighting.

On August 27, 2019, Cal/OSHA is convening an advisory committee meeting to begin the process of developing the permanent standard.  This emergency regulation will be in effect for one year while Cal/OSHA develops the permanent standard.

To review the complete text of the regulations, visit

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