Wildfire Smoke - Washington (DOSH)

Smoke season in Washington can turn a clear morning into a hazy afternoon without anyone noticing the change. Washington's wildfire smoke rule, chapter 296-820 WAC, is permanent and year-round, and it does not wait for the sky to turn orange. It works as a ladder of fine-particle (PM2.5) levels, and the first step comes early: a written response plan and crew training before anyone works in smoke at 20.5 µg/m³. This Washington Wildfire Smoke Toolbox Talk walks the crew up the ladder, one step at a time.

Where the boundary of this talk sits#

This talk covers what Washington's wildfire smoke rule requires on a construction site. How smoke affects the lungs and heart, how to wear and fit-check an N95, and general respiratory protection belong to their own talks.

The anchor#

Here is the distinction that carries this whole talk: Washington's wildfire smoke rule is a ladder of PM2.5 levels, and each step adds a duty — at 20.5 µg/m³ (AQI 72) the employer needs a wildfire smoke response plan in the written accident prevention program, trained workers, and notice to the crew; at 35.5 (AQI 101) exposure controls where feasible and free N95s for everyone; at 250.5 (AQI 351) N95s handed directly to each worker; at 500.4 (AQI 849) a full respiratory protection program; and at 555 (AQI 957) respirators with a higher protection factor — so the question on a smoky day is not "is it bad out?" but "which step are we on right now, and what does it require?"

Who is covered#

WAC 296-820-805 applies to all workplaces, including agricultural ones, with four exceptions: enclosed buildings or structures with windows, doors, bays, and other openings kept closed except to briefly enter and exit; enclosed vehicles with a properly maintained cabin air filter and closed windows and doors; firefighting work under chapter 296-305 WAC; and workers performing prescribed burns. A construction site with open framing or a worker in an open equipment cab is covered.

Step zero: know the number#

WAC 296-820-815 requires the employer to determine the current PM2.5 periodically as needed. Acceptable sources include the Washington Department of Ecology website, the Air Quality WA app, the Washington smoke information website, the EPA Fire and Smoke Map, AirNow, the Forest Service AirFire website, and local clean air agencies, or the employer can measure PM2.5 at the work location under WAC 296-820-845. "Current PM2.5" means the hourly average for the most current hour available. Smoke moves with the wind, so a morning reading says little about the afternoon.

The rule is written in micrograms per cubic meter (µg/m³), with the AQI shown alongside. Go by the concentration.

20.5 µg/m³ (AQI 72): plan, train, tell#

• Plan. WAC 296-820-820 requires a wildfire smoke response plan in the written accident prevention program before work that exposes a worker to 20.5 µg/m³ or more.
• Train. WAC 296-820-825 requires training for all workers before that exposure, and at least annually after, covering the Appendix A topics, including health effects, symptoms, the right to medical attention, how PM2.5 is determined, and the benefits and limits of respirators. Supervisors get additional training on procedures and on getting a sick worker to medical care.
• Tell. The communication system must notify workers when at least two consecutive current readings are 20.5 µg/m³ or more, and again at 35.5, 250.5, 500.4, and 555. It must also include provisions that encourage employees to report wildfire smoke hazards without fear of reprisal.

At this level the employer is also encouraged, but not required, to use exposure controls and to offer N95s on request.

35.5 µg/m³ (AQI 101): controls and N95s for all#

WAC 296-820-835(2) requires effective exposure controls whenever feasible. The rule lists examples: enclosed buildings, structures, or vehicles with adequately filtered air; portable HEPA filters in enclosed areas; relocating work to a place with lower PM2.5; changing schedules to cleaner times; avoiding work that creates extra dust, fumes, or smoke; reducing work intensity; and more rest periods. Controls are not required during emergency response.

WAC 296-820-840(2) requires the employer to provide N95 filtering-facepiece respirators at no cost to all exposed employees and to encourage their use.

250.5 µg/m³ (AQI 351): N95s handed out#

WAC 296-820-840(3) requires the employer to distribute N95 respirators directly to each exposed employee. A box in the trailer is no longer enough.

500.4 µg/m³ (AQI 849): a full respirator program#

WAC 296-820-840(4) requires employees to be enrolled in a complete respiratory protection program under chapter 296-842 WAC, which brings in medical evaluation and fit testing. It does not apply to employees exposed for a total of 15 minutes or less in a 24-hour period.

555 µg/m³ (AQI 957): more protection#

WAC 296-820-840(5) keeps the full program and requires the employer to provide, and require the wearing of, a loose-fitting powered air-purifying respirator, a full-facepiece air-purifying respirator, a full-facepiece powered air-purifying respirator, or another respirator with an assigned protection factor of 25 or more, so PM2.5 inside the respirator stays below 55.5 µg/m³.

All respirators must be NIOSH-approved, and filtering facepieces must not be cleaned or shared.

When someone has symptoms#

WAC 296-820-830 requires the employer to let workers with symptoms seek medical attention or follow medical advice without retaliation, and to monitor them. Symptoms that need immediate medical attention include difficulty breathing, asthma attacks, chest pain, nausea or vomiting, and sudden numbness, confusion, or trouble seeing, speaking, or walking. At 250.5 µg/m³ or more, a worker with those symptoms must be moved to clean air, such as a place below 20.5 µg/m³ or an enclosed space with enough HEPA filtration. While care is being arranged, or where medical attention is not needed, the employer must still reduce or eliminate the worker's continued exposure as appropriate to their symptoms, the exposure level, and the controls in place. Arrangements for prompt medical attention must be made in advance.

Washington versus federal#

There is no federal OSHA standard written specifically for wildfire smoke. Washington's rule sets its own ladder of PM2.5 levels and duties. For comparison, California's rule starts at an AQI of 151, while Washington's first duties begin at AQI 72.

Where the duty sits#

WAC 296-820-805 sets scope and exemptions. WAC 296-820-815 sets how PM2.5 is determined. WAC 296-820-820 sets the response plan and notice. WAC 296-820-825 sets training. WAC 296-820-830 sets symptom response. WAC 296-820-835 sets controls at 35.5. WAC 296-820-840 sets respirators at 35.5, 250.5, 500.4, and 555.

What can go wrong?#

• Nobody checks the reading because the sky looks fine.
• The crew was never trained, and the first smoky day arrives.
• N95s are "in the trailer somewhere" at a reading of 300 µg/m³.
• A worker with chest pain is told to take a break in the same air.
• The crew reads an AQI off an old handout instead of checking the current µg/m³ number.

How do we manage this properly?#

• Check the number — from an approved source, as often as conditions change.
• Have the plan and training in place — before the first exposure at 20.5.
• Tell the crew at each step — and make it safe to report symptoms.
• At 35.5, control and provide — filtered spaces, schedule changes, free N95s.
• At 250.5, hand them out — one to each worker.
• At 500.4, full program — fit-tested, medically cleared.

Before you start#

Check the current PM2.5 before work and again when conditions change. Know which step we are on, where the N95s are, and where the clean-air space is. If you feel symptoms, say so right away.

Talk it over#

• What is the current PM2.5, and where did we get it?
• Which step does that put us on, and what does it require?
• Where would we take someone who can't breathe?

The bottom line#

Washington's wildfire smoke rule is a year-round ladder. At 20.5 µg/m³ (AQI 72): a written plan, training, and notice. At 35.5 (AQI 101): controls where feasible and free N95s. At 250.5 (AQI 351): N95s handed to each worker. At 500.4 (AQI 849): a full respirator program. At 555 (AQI 957): higher-protection respirators. Know the number, know the step, and let anyone with symptoms get to clean air and care.

Frequently asked questions about the Washington wildfire smoke rule#

When do N95s become required in Washington wildfire smoke?

At a current PM2.5 of 35.5 µg/m³ (AQI 101), the employer must provide N95s at no cost to all exposed employees and encourage their use. At 250.5 µg/m³ (AQI 351), they must be distributed directly to each worker. At 500.4 µg/m³ (AQI 849), employees must be in a full respiratory protection program.

Download the Washington wildfire smoke toolbox talk PDF#

Download this Washington Wildfire Smoke Toolbox Talk as a printable PDF in English and Spanish, and train the crew before smoke season starts.

Related toolbox talks#

• Respiratory Protection
• Extreme Weather
• Heat Stress
• Dust and Silica

Sources#

• Washington State Legislature, WAC 296-820-805 — Purpose and scope (all workplaces; exemptions for closed buildings, filtered closed vehicles, firefighting, prescribed burns): https://app.leg.wa.gov/wac/default.aspx?cite=296-820-805
• Washington State Legislature, WAC 296-820-810 — Definitions (current PM2.5 as hourly average): https://app.leg.wa.gov/wac/default.aspx?cite=296-820-810
• Washington State Legislature, WAC 296-820-815 — Identification of harmful exposures (approved sources; measurement): https://app.leg.wa.gov/wac/default.aspx?cite=296-820-815
• Washington State Legislature, WAC 296-820-820 — Hazard communication (response plan in the APP at 20.5 µg/m³; notice at two consecutive readings of 20.5, and at 35.5, 250.5, 500.4, 555; reporting without reprisal): https://app.leg.wa.gov/wac/default.aspx?cite=296-820-820
• Washington State Legislature, WAC 296-820-825 — Information and training (before exposure at 20.5 and annually; supervisors): https://app.leg.wa.gov/wac/default.aspx?cite=296-820-825
• Washington State Legislature, WAC 296-820-830 — Exposure symptom response (no retaliation; immediate-attention symptoms; clean air at 250.5): https://app.leg.wa.gov/wac/default.aspx?cite=296-820-830
• Washington State Legislature, WAC 296-820-835 — Exposure controls (encouraged at 20.5; required where feasible at 35.5): https://app.leg.wa.gov/wac/default.aspx?cite=296-820-835
• Washington State Legislature, WAC 296-820-840 — Respiratory protection (N95s at 35.5; distributed at 250.5; full program at 500.4, 15-minute exception; APF 25 or more at 555; WSR 25-09-064, effective 5/16/25): https://app.leg.wa.gov/wac/default.aspx?cite=296-820-840
• Washington L&I, Outdoor workers gain year-round protections from dangerous wildfire smoke (permanent rules in effect year-round from January 15, 2024): https://www.lni.wa.gov/news-events/article/23-034/

Written by FieldSafetyTalk's safety professional — a CSP, ASP, CHST and OSHA Authorized Outreach Trainer with 14+ years of international construction safety experience across federal, heavy civil, and industrial projects.

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