Insights
Working in Wildfire Smoke: What Employers Must Do
Every wildfire season, the same question comes up: at what smoke level does Alberta law require stopping outdoor work? The honest answer is that there isn't one. Wildfire smoke is governed by the same general hazard-assessment duty as any other airborne hazard - which puts more judgment, not less, on the employer.
Published 5 Sep 2026 · The On-Track Team
6 min readKey Takeaways
- Alberta's OHS Act and Code have no wildfire-smoke-specific section and no codified AQHI trigger number.
- The legal duty runs through the general hazard assessment framework: identify, assess, and control as far as reasonably practicable.
- Alberta OHS publishes non-binding guidance (bulletins FI007 and FI008) with practical controls - none of them mandatory at a set threshold.
- Respirators, rescheduling, and clean-air breaks are recommended controls, not legal requirements triggered at a specific smoke level.
- British Columbia's approach is more developed in guidance and campaigns, but it isn't a fundamentally different codified standard from Alberta's.
1. Why there's no numeric rule
Wildfire smoke doesn't appear as its own hazard category anywhere in the OHS Act (SA 2020, c O-2.2) or the OHS Code (Alberta Regulation 191/2021). It falls under Part 2 (Hazard Assessment, Elimination and Control) and Part 4 (Chemical Hazards, Biological Hazards and Harmful Substances) - the same general framework that covers dust, fumes, or any other airborne contaminant. There is no codified Air Quality Health Index (AQHI) number that triggers a legal obligation to stop or modify outdoor work.
What the AQHI actually is
2. What the general duty actually requires
Section 3 of the OHS Act requires an employer to ensure, as far as reasonably practicable, the health, safety, and welfare of workers. Applied to smoke, that means: identify when smoke is present and could affect outdoor work, assess how much exposure workers actually face given the task and duration, and put controls in place that reduce that exposure as far as reasonably practicable. Alberta's own guidance notes that at a distance from an active fire, contaminant levels are often below occupational exposure limits even when the air looks and smells smoky - which is part of why no blanket numeric rule exists.
3. Controls to document
None of the following is individually mandatory at a set threshold, but a hazard assessment that shows none of them were considered is a weak one:
- Monitoring local air quality and adjusting the work plan as conditions change through the day
- Rescheduling or relocating the most strenuous tasks to lower-smoke periods or areas
- Shortening shifts or building in additional breaks, ideally in a filtered or cleaner-air space
- Providing N95 or better respirators where the assessment supports it, with fit and training in place
- Communicating the plan to workers before the shift, not improvising it on site
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A hazard assessment that actually holds up to review
A custom safety manual builds seasonal hazards like wildfire smoke into the formal hazard assessment for the tasks and sites you actually run - not a generic checklist copied from a bulletin.
See custom safety manual options4. How this compares to BC
British Columbia is often described as having a stricter, codified wildfire-smoke regulation. In practice, WorkSafeBC applies the same category of general framework Alberta does - indoor air quality provisions, exposure control plans, and PPE requirements - rather than a standalone wildfire-smoke section with a numeric trigger. What genuinely differs is the volume of practitioner guidance and public campaign material BC has built around it, not a fundamentally different legal standard.
5. Frequently asked
Is there an AQHI number that legally requires stopping outdoor work in Alberta?
No. Alberta's OHS Act and OHS Code do not set a numeric Air Quality Health Index trigger for modifying or stopping outdoor work. The AQHI scale on Alberta's wildfire-smoke information page is a public-health communication tool, not an occupational threshold. The legal duty is the general one: assess the hazard and control it as far as reasonably practicable.
Are N95 respirators mandatory for outdoor workers during smoky conditions?
No specific respirator mandate exists at any AQHI level. Alberta's own guidance recommends N95 or better respirators as one available control, alongside relocating work, shortening shifts, and providing breaks in cleaner air - but none of these is legally mandatory at a defined trigger point. An employer's hazard assessment should still document which controls it chose and why.
Does British Columbia have a stricter wildfire smoke rule than Alberta?
Not as codified as it's sometimes described. WorkSafeBC does not have a standalone wildfire-smoke regulation with numeric triggers either - it applies the same general framework (indoor air quality, exposure control plans, PPE requirements) as Alberta. Where BC differs in practice is more developed public guidance and recurring campaign material, not a fundamentally different legal standard.
What should a wildfire smoke hazard assessment actually document?
The same structure as any other hazard assessment: the hazard (smoke, reduced air quality, physical exertion in poor air), who is exposed and for how long, the controls chosen (monitoring conditions, rescheduling strenuous tasks, providing clean-air rest areas, respirators where appropriate), and how workers were informed. Alberta's own bulletins (FI007, FI008) are a reasonable template to work from, even though they are guidance rather than law.
Does WCB Alberta treat wildfire smoke exposure differently for claims?
WCB Alberta's published wildfire-related material focuses on claims-cost relief and modified-work provisions tied to wildfire evacuations and business disruption, not a specific smoke-exposure claims category. A smoke-related respiratory claim would be assessed under WCB's general claims process like any other workplace exposure.