Workplace Radon in Canada

For employers, building owners and facilities teams. If you are testing a home, start with our Canada radon map and residential guides instead — this section covers buildings with a duty holder.

Radon is the second leading cause of lung cancer in Canada, and the rules covering it in workplaces and public buildings are changing. On 30 January 2027, the exposure limit for federally regulated workplaces drops from 800 Bq/m³ to 200 Bq/m³, measured as an annual average (SOR/2026-10, Canada Gazette Part II). Provincially regulated employers, schools, landlords and builders face a different but related set of duties.

The short version. Federally regulated employers must ensure no employee is exposed above 200 Bq/m³ as an annual average from 30 January 2027. Provincially regulated employers owe a general duty covering recognised hazards, with the same 200 Bq/m³ guideline as the benchmark. Testing follows Health Canada's Guide for Radon Measurements in Public Buildings — three months minimum during the heating season, a detector in every occupied ground-contact room. The deployment window runs roughly 1 October to the end of January, and only one heating season remains.

Last reviewed August 2026. Everything below is free, cites primary sources, and attributes all health guidance to Health Canada.

Start here

1. The federal rule

• Canada's new workplace radon limit: SOR/2026-10 explained — what the regulation says, who it covers, the dates, and where the number came from.
• Does my workplace need radon testing? Federal and provincial rules — the coverage test, the derivative jurisdiction framework, and the confusing cases: banks vs credit unions, airport tenants, contractors, insurance and trust companies.
• The compliance timeline — the annual-average arithmetic and the 1 October to end-of-January deployment window.
• The workplace radon legal brief — statute by statute, with operative wording, records and enforcement. Also available as a PDF.
• Workplace radon FAQ — the questions employers and committees ask most.

1b. The research

• 603,000 Canadian workers are exposed to radon — and the most exposed aren't miners — what the peer-reviewed evidence says about who is exposed, at what levels, and how that maps against the new federal limit.

2. Provincial duties

• Our staff asked about radon — what now? — what you are actually obliged to do, what a good answer looks like, and why the question having been asked is the thing that changed.
• Workplace radon rules by province — general duty clauses, Ontario's NORM framework, and three widely repeated claims that are wrong.
• Quebec: the employer's obligations (CNESST) — why there is no number in the RSST, and what applies instead.

3. Compliance: the record and the people

• The radon business case — for health and safety managers who need budget approval: the obligation, the evidence, the cost drivers, the phased option, and what deferring costs. Also available as a PDF.
• What a compliant radon record contains — the document set the regulations require. A laboratory certificate is one of five elements.
• Does a certified professional have to do the testing? — what "qualified person" means, who decides, and when to engage a professional anyway.
• Can't test every building this season? — the compliance continuum, Assurances of Voluntary Compliance, and what a defensible phased plan contains.
• How to risk-rank a building portfolio — which buildings first, the evidence behind each factor, and what a ranking cannot do.

4. How testing works

• Commercial radon testing: process, detector counts and cost — the protocol, how many detectors a building needs, and consultant versus in-house delivery.
• Radon, HVAC and ventilation — how ventilation drives results, the occupied-hours correction, and when an HVAC change means retesting.
• Our result came back at 180 — are we finished? — borderline results, the watch band, and the 50 per cent criterion in the regulations.
• Post-mitigation verification — the confirmation sequence, the five-year cycle, and why Health Canada recommends the installer not perform the test.

5. By building type

• Radon in your child's school: a guide for parents — how to ask, which provinces have already tested all their schools, and how to read the answer. Free to reproduce. Also available as a PDF.
• Schools and daycares — where testing is required, where it isn't, and why children are treated differently.
• Hospitals, care facilities and correctional centres — continuous occupancy, vulnerable populations, and the ventilation correction that doesn't apply here.
• Landlords, property managers and multi-unit buildings — who owes the duty, and why every ground-contact unit is measured rather than a sample.
• Band councils and First Nations buildings — federally regulated, and rarely discussed.

6. For workers and committees

• A toolkit for union representatives — the mechanism behind the ask, how to tell a real test from a token one, and how to raise radon across multiple worksites. Free to reproduce. Also available as a PDF.
• Radon at work: a guide for workers and committees — how to raise it, what a proper test looks like, and what the numbers mean. Free to reproduce. Also available as a PDF.

6b. For employee benefits and wellness programmes

• Radon testing as an employee benefit — employer-funded home radon testing for staff, how the privacy architecture works, and what it does not replace.
• Work from home? Who pays to test for radon — for employees: whether an employer should fund it, how to ask, and what to do if the answer is no.

7. New construction and building codes

For builders, developers and building officials.

• Radon rough-in requirements for builders — what the 2025 National Building Code requires, and post-occupancy verification.
• Is a radon rough-in mandatory in my province? — dated status by jurisdiction, and why "national" doesn't mean "everywhere".
• Radon rough-in inspection — the pre-pour window, labelling, and the CRNCH credential gap.
• Canadian building codes and radon — how codes have handled radon over time.

En français

The complete workplace radon guide is also available in French: Le radon en milieu de travail au Canada.

• Norme radon au Québec — les seuils qui s'appliquent réellement.
• Obligations de l'employeur québécois (CNESST)
• La nouvelle limite fédérale (DORS/2026-10)
• Mon lieu de travail est-il visé ?
• Échéancier de conformité
• Règles par province
• Que doit contenir un dossier conforme
• Faut-il un professionnel certifié ?
• La conformité progressive
• Classer un parc immobilier par risque
• Dépistage du radon en milieu commercial
• Radon, CVCA et ventilation
• Un résultat juste sous 200 Bq/m³
• Vérification après atténuation
• FAQ — radon au travail et en garderie
• Propriétaires et immeubles multilogements
• Hôpitaux, établissements de soins et détention
• Guide pour les travailleurs et les comités
• Radon et construction neuve
• Code de construction du Québec et radon
• Garantie GCR et radon
• Inspection du rough-in de radon

What to do next — the practical sequence

If you are responsible for buildings and want a plan rather than a reading list, this is the order the work actually happens in.

1. Confirm your jurisdiction. Federal or provincial changes what you owe and when. Start with which rules apply to your workplace. Where it is genuinely arguable, the Labour Program can determine it.
2. Inventory your buildings. List every building you occupy, note which levels are in ground contact, and count the rooms occupied more than four hours a day. That room count — not floor area, not headcount — drives everything downstream.
3. Rank by risk and prioritise. If you cannot test everything in one heating season, a documented prioritisation is what makes a phased approach defensible. See how to risk-rank a portfolio.
4. Decide who does the work. The regulation requires a qualified person, defined by knowledge, training and experience. Understand the difference between what is required and what is recommended: the qualified person question.
5. Test long-term, during the heating season. Minimum three months, every occupied ground-contact room, one detector per 200 m² in larger rooms, plus quality-control duplicates and blanks.
6. Build the record as you go. Date, time and location of each test; the substance tested for; the method; the result; and the name and occupation of the person who performed it. A laboratory certificate supplies only the result.
7. Act on results, then verify. Above 200 Bq/m³, Health Canada's public-buildings guide sets the remediation timeframes — within two years for 200–600 Bq/m³, within one year above 600 — followed by confirmation testing — performed, per Health Canada's guidance, by someone other than the installer.
8. Keep it running. Retest triggers, renovation and energy-retrofit triggers, worker and committee communication, and a calendar that survives staff turnover.

Steps 1 through 3 and 6 through 8 are documentation and scheduling. Only steps 4 and 5 involve anyone touching the building.

Look up your area

Measured radon results across Canada, searchable by postal code and city: the Canada Radon Map.

Testing a home rather than a workplace? Our residential guides cover homes, new builds and warranty coverage.

RadonTest.ca provides testing logistics and laboratory submission. We do not perform radon mitigation and we do not interpret health risk — Health Canada is the health authority on radon in Canada. These guides describe publicly available regulatory information and are not legal advice.

Sources

Every figure on this page comes from one of the following. Each is the primary document, not a summary of it.

• Canada Gazette, Part II, Vol. 160, No. 3 — SOR/2026-10 — the amending instrument: the 200 Bq/m³ limit, the exclusion for nuclear energy workers, the 30-year record retention, and the coming-into-force date of 30 January 2027.
• Canada Occupational Health and Safety Regulations (SOR/86-304) — the consolidated regulations, including Part X: s. 10.3 records, s. 10.4 the qualified person, s. 10.5–10.6 the report and its retention, s. 10.19 sampling records, s. 10.26 ionizing radiation.
• Health Canada — Guide for Radon Measurements in Public Buildings — the measurement protocol (three months in the heating season, one detector per occupied ground-contact room, one per 200 m² in larger rooms, duplicates and blanks) and the remediation timeframes in its Table 3.
• Health Canada — Canadian radon guideline — the 200 Bq/m³ guideline itself, and the separate guidance that applies to homes.
• Employment and Social Development Canada — amendments to regulations under Part II of the Canada Labour Code — scope, enforcement and the compliance approach.

Health Canada's guidance for homes differs from its guidance for public buildings — most visibly on remediation timing. Figures on this page are the public-buildings ones unless stated otherwise.