Canadian Wildfire Smoke: What Ag Employers in Northern States Need to Know

Seso is actively monitoring the heavy Canadian wildfire smoke moving across the northern United States this summer. Growers from Washington to Wisconsin to New York are reporting hazy skies, reduced visibility, and workers struggling to breathe during outdoor tasks. Several of our clients have already reached out with the same core question: Do I need to hold operations, and how do I protect my crew while staying on the right side of the rules?

There is no single federal wildfire-smoke standard, which leaves many employers unsure of their obligations. But there is a clear, workable framework built on OSHA's General Duty Clause, EPA air quality data, and—in a few states—specific wildfire-smoke regulations. Below is practical guidance employers can put to work today.

Start by Monitoring Air Quality

You cannot manage exposure you are not measuring. Before each shift, and again if conditions change, check the current Air Quality Index (AQI) for your location, focusing on PM2.5—the fine particulate in smoke that poses the greatest health risk.

• EPA AirNow: https://www.airnow.gov/

• EPA Fire and Smoke Map: https://fire.airnow.gov/

Both tools are free and update in real time. The AQI reading is what should drive your operational decisions throughout the day.

A Tiered Approach Based on AQI

Federal and state guidance generally points to the following action bands for outdoor work:

• AQI 0–100 (Good to Moderate): Continue normal operations. Monitor AQI at least daily and educate workers on symptoms to watch for, including coughing, throat irritation, and difficulty breathing.

• AQI 101–150 (Unhealthy for Sensitive Groups): Identify sensitive workers (asthma, COPD, heart conditions). Consider task modifications, more frequent breaks in filtered indoor spaces, and make NIOSH-approved N95 respirators available for voluntary use.

• AQI 151–200 (Unhealthy): This is the key action threshold. Relocate work to lower-smoke areas or times of day where feasible, reduce work intensity and duration, add rest breaks in enclosed filtered spaces, and provide N95 respirators.

• AQI 201 and above (Very Unhealthy to Hazardous): Suspend outdoor work except for essential tasks. Any work that must continue outdoors should be performed with appropriate respiratory protection and kept as brief as possible.

Understand Your OSHA Obligations

Wisconsin and most northern states affected by drifting Canadian smoke fall under federal OSHA jurisdiction and do not have a state-specific wildfire-smoke standard. In those states, OSHA's General Duty Clause (29 U.S.C. § 654(a)(1)) governs. It requires employers to protect workers from recognized hazards—and heavy wildfire smoke qualifies. The most effective, feasible way to meet that duty is to monitor air quality, reduce exposure, and provide respiratory protection when the air turns unhealthy. OSHA offers general guidance on protecting workers from wildfire smoke.

A note on respirators: providing N95s for voluntary use carries limited requirements. But if respirator use becomes mandatory, 29 C.F.R. § 1910.134 generally requires a written respiratory protection program, medical evaluations, and fit-testing. Employers should know which side of that line they are on before requiring masks.

Three States Have Their Own Wildfire-Smoke Rules

Employers operating in California, Oregon, or Washington are held to specific standards beyond the General Duty Clause:

• California (Cal/OSHA), Title 8 § 5141.1: Protections apply at AQI 151 or greater for PM2.5. Employers must check AQI at the start of each shift and periodically after, train workers, communicate the hazard in an understandable manner, and reduce exposure through engineering controls where feasible. See also Cal/OSHA's worker protection guidance.

• Oregon OSHA: Obligations begin at a lower threshold—PM2.5 at or above 35.5 µg/m³ (roughly AQI 101, "Unhealthy for Sensitive Groups"). See Oregon OSHA's rule fact sheet.

• Washington (L&I), Chapter 296-820 WAC: Information and training requirements can begin as early as AQI 72, with additional protective measures layering in as air quality worsens.

Do Not Overlook Employer-Provided Housing

For employers who provide worker housing, that housing must offer a genuine refuge from smoke—reasonably sealed against outdoor air and filtered where possible—consistent with H-2A housing obligations under 20 C.F.R. § 655.122(d). Housing that is as smoky as the field does not meet the standard.

Immediate Action Steps for Employers

1. Monitor AQI in real time. Check AirNow.gov at the start of each shift and as conditions change.

2. Adjust operations to the AQI band. Suspend or modify outdoor work when readings reach unhealthy levels.

3. Provide NIOSH-approved respirators. Supply N95s or better at no cost to workers who must continue outdoors.

4. Communicate with workers. Explain the hazard, protective measures, and warning symptoms in a language each worker understands, and encourage immediate reporting of symptoms.

5. Maintain safe housing. Ensure employer-provided housing is sealed and filtered against smoke.

6. Document everything. Record the AQI readings consulted, the dates and times operations were modified or suspended, protections provided, worker communications, and any complaints or symptoms. This documentation is important in the event of OSHA or DOL scrutiny.

How Seso Can Help

The decision on when to pause operations ultimately rests with each employer, but you do not have to navigate it alone. Seso helps growers keep worker communications, safety documentation, and compliance records organized in one place—so when conditions change quickly, you can act quickly and have the paper trail to back it up. If your operation has been affected by wildfire smoke, reach out to your Seso representative to discuss next steps.

Seso will continue to monitor air quality developments across the northern states and share updates as new guidance becomes available.

This article is provided for general informational purposes only and does not constitute legal advice. For guidance on your specific situation, consult a qualified attorney or your state OSHA office.