Wildfire smoke and outdoor work: what the rules in California, Oregon, Washington and British Columbia say

This page reports what the official source says. It is not legal advice: ask the office named here. None of these rules is written only for tree work, and each text lists the workplaces it leaves out. The guide on wildfire plans and tree clearing covers fire-season rules for the work itself, and the guide on health hazards in tree work is the wider list of hazards.

Triggers side by side

Place	Trigger as worded
California, Title 8 section 5141.1	Applies where the NowCast Air Quality Index for PM2.5 is 151 or greater and the employer should reasonably anticipate wildfire smoke exposure. Exempt: exposure of one hour or less in total during a shift.
Oregon, OAR 437-002-1081	PM2.5 at or above 35.5 micrograms per cubic metre. Oregon OSHA says the May 2024 change to how the EPA calculates AQI did not change these PM2.5 thresholds.
Washington, chapter 296-820 WAC	Steps by PM2.5 level from 20.5 micrograms per cubic metre (AQI 72), with duties from 35.5 (AQI 101).
British Columbia, WorkSafeBC	The August 12, 2026 notice gives no numeric trigger. It says employers must assess workplace risks and put suitable measures in place to reduce exposure.

California

Section 5141.1 of Title 8 is on the Department of Industrial Relations site. The employer finds out the AQI at the start of each shift and periodically after, by checking forecasts from named agencies or by measuring PM2.5 at the worksite. The section asks for a communication system, in a language and manner workers understand, that includes ways for workers to report worsening air quality and symptoms without fear of reprisal, and for training covering its Appendix B. Controls come in an order. Where feasible, engineering controls reduce exposure to below AQI 151, for example filtered enclosed buildings or vehicles. If that is not feasible, administrative controls where practicable: moving work, changing schedules, reducing intensity or adding rest periods. At AQI 151 up to 500 the employer provides enough respirators for voluntary use and encourages their use, NIOSH-approved and protective against PM2.5, with N95 filtering facepieces as the example. Above AQI 500 respirator use is required. The section exempts wildland firefighters, and sets separate rules for emergency operations.

Oregon

The Oregon OSHA fact sheet on the permanent wildfire smoke rules sets three bands by PM2.5. The table shows the bands as the fact sheet prints them, with the AQI values before and after May 2024.

PM2.5, micrograms per cubic metre	AQI before and after May 2024	Duties listed
35.5 or more	101 to 250 before, 101 to 276 from May 2024	Assess and monitor air quality, training, two-way communication, engineering and administrative controls, filtering facepiece respirators for voluntary use
200.9 or more	251 to 500 before, 277 to 848 from May 2024	The above, plus respirators for mandatory use under a wildfire smoke respiratory protection program
500.4 or more	501 and above before, 849 and above from May 2024	The first four duties, plus respirators for mandatory use under a respiratory protection program under 29 CFR 1910.134 or the Oregon equivalent

The fact sheet says the rules do not apply to enclosed buildings or vehicles with filtered air and closed openings, to employers that predetermined to suspend operations at PM2.5 of 35.5 or more, or to employees working at home. It says wildland firefighting and emergency operations are partly exempt, as is work with intermittent exposure of less than 15 minutes in an hour and less than one hour in 24 hours.

Washington

Chapter 296-820 WAC (last update 1/6/26) has sections on purpose and scope, definitions, identification of harmful exposures, hazard communication, training, exposure symptom response, exposure controls, respiratory protection and measuring PM2.5. Section 296-820-805 exempts enclosed buildings and filtered-air vehicles with closed openings, firefighter work under another chapter, and prescribed burns. The tiers in section 296-820-840 are in the table.

PM2.5 (AQI)	What the rule says
20.5 to 35.4 (72 to 100)	Employer is encouraged to provide N95 filtering facepieces at no cost on request, and to use exposure controls
35.5 to 250.4 (101 to 350)	Employer must provide N95 filtering facepieces at no cost to all exposed employees, must encourage use, and must implement effective exposure controls whenever feasible
250.5 to 500.3 (351 to 848)	Employer must hand N95 filtering facepieces directly to each exposed employee and encourage use
500.4 to 554.9 (849 to 957)	Required respirator use under a full respiratory protection program, except for 15 minutes or less of exposure in 24 hours
555 or more (957)	Required use of a higher class of respirator, again under a full program

The exposure controls in section 296-820-835 include filtered buildings or vehicles, portable HEPA filters, moving work, changing schedules, avoiding extra dust, fumes or smoke, reducing intensity, and added rest periods. The section says it is not required during emergency response.

British Columbia

The regulator WorkSafeBC published an August 12, 2026 notice, which says wildfire smoke carries fine particles that can travel far and reach workers a long way from active fires. It says employers must assess workplace risks where evacuation or rescue may be needed, and make workers aware of evacuation procedures, communication methods and escape routes. It lists actions employers can consider, such as monitoring air quality advisories, relocating or rescheduling work, reducing physically demanding tasks, assigning alternate work to more sensitive employees, and providing respiratory protection when required. The notice does not give a smoke level for those steps. The guide on tree waste rules in British Columbia covers burning rules, which are a separate subject from exposure to smoke at work.