This is written for union health and safety representatives, national and local health and safety officers, and anyone whose job includes raising hazards across more than one employer. It assumes you know how to run a health and safety file and focuses on what is specific about radon.
Free to reproduce. Circulate it, put it in a newsletter, hand it out at a meeting. No permission needed — please keep the attribution so people can find the current version.
Why radon is worth your attention now. On 30 January 2027 the exposure limit for federally regulated workplaces drops from 800 to 200 Bq/m³ as an annual average — a fourfold tightening. Peer-reviewed Canadian research puts 603,000 workers above 100 Bq/m³, and the most affected occupations are administrative assistants, office support workers, receptionists and elementary teachers — not miners. The measurement window is seasonal and effectively closes at the end of January, so the ask has a clock on it that most people have not noticed.
What makes radon different from most hazards you raise
Three things, and each one changes the tactics.
It is invisible and it cannot be inferred. There is no walkthrough that reveals it, no symptom to point at, no condition an inspector can observe. The only way anyone knows is a measurement. That makes the ask unusually simple: you are not asking for an assessment or an opinion, you are asking whether a number exists.
Most employers genuinely have not thought about it. Radon has not historically been part of building management in Canada. In most cases you will not be pushing against resistance so much as against unfamiliarity, and that calls for a different opening than a hazard the employer has already declined to fix.
The risk is cumulative and long-latency. Nobody gets sick this week. That makes it easy to defer indefinitely, which is exactly why documenting the ask matters more here than with a hazard that produces incidents.
The ask, and the mechanism behind it
The core question is deliberately narrow:
“Has this building been tested for radon? If so, when, what were the results, and where are the records kept? If not, what is the plan to test during the coming heating season?”
Put it in writing, through the committee, and get it minuted. Then the mechanism does some of the work for you.
Federally regulated workplaces
- An employer must respond in writing to a committee recommendation within a defined period under the Canada Labour Code, and must provide the committee with hazard-assessment reports.
- Where a hazard investigation is required, the employer appoints a qualified person, notifies the committee of the investigation and of that person's name, and the resulting report is signed and retained for thirty years.
- The employer must also keep a written control procedure, kept current and readily available for examination by employees. If one exists, you are entitled to see it.
- A worker may complain directly to the Labour Program without raising the matter with the employer first — though in practice the committee route resolves most of these and should be tried first.
Provincially regulated workplaces
No province or territory has a numeric radon exposure limit. What applies is the general duty to take reasonable precautions against recognised hazards — and once you have raised radon in writing, it is a hazard the employer knows about. The general duty is principally about what happens after identification.
Details by jurisdiction: workplace radon rules by province.
Two edge cases worth knowing
In the territories, private-sector firms in Yukon, the Northwest Territories and Nunavut are federally regulated for labour relations, but their occupational health and safety is governed by territorial legislation — the Yukon Occupational Health and Safety Act, and the Safety Act administered by the Workers' Safety and Compensation Commission in the Northwest Territories and Nunavut. The federal 200 Bq/m³ limit does not reach them by that route.
And your own local's office. A union is an employer for its own staff, and in almost all cases a provincially regulated one. If you are asking employers to test their buildings, it is worth knowing the answer for your own.
How to tell a real answer from a token one
This is where a representative adds the most value, because a token test is common and looks like compliance to anyone who has not read the protocol.
| What you may be told | What to check |
|---|---|
| “We tested and it was fine.” | Ask for the report. Date, method, number of detectors, locations, laboratory, and the actual numbers. |
| “We did a test.” | How many detectors? Health Canada's public buildings protocol requires one in each occupied room in contact with the ground, one per 200 m² in larger areas, plus quality-control detectors. One reading for a building is not a compliant measurement. |
| “We used a monitor.” | Short-term readings and continuous monitors are not appropriate for deciding whether to act. The protocol requires a long-term measurement of at least three months. |
| “We tested in the summer.” | Measurement should be during the heating season, when the building behaves as it does most of the year. A summer-only result that comes back low is not a reliable answer. |
| “It was tested years ago.” | Ask whether there have been renovations, ventilation changes, an energy retrofit or a change in how the lower floors are used. Any of those is a reason to retest. |
| “The result was under 200, so nothing to do.” | Correct as far as it goes. Worth asking where in the range it fell — Health Canada notes that mitigation is worth considering as results approach the guideline. |
What a compliant record contains, in full: what a compliant workplace radon record contains. The short version is that a laboratory certificate is one of five elements, and four of the five are generated in the building rather than by the lab.
Raising it across multiple employers
This is where a union representative can do something a single committee member cannot.
Ask the same question everywhere, in the same words. Identical wording across sites produces comparable answers, and the pattern in those answers is itself information — if eleven of twelve sites have never tested, that is a bargaining fact rather than an anecdote.
Start with the buildings most likely to be affected. Occupied space at or below grade, older buildings, and regions with higher measured levels. Our Canada radon map shows measured results by area — regional data indicates probability, never a result for a specific building.
Watch for the phased-plan answer, and take it seriously. An employer with many buildings may reasonably say they cannot test everything in one heating season. A documented, risk-ranked, phased plan is a legitimate response. “We will test everything eventually” without a schedule is not. The distinction is a written plan with dates.
Bargaining and policy. Radon testing on a defined cycle, and a commitment to act on results within Health Canada's timelines, is a concrete and low-cost thing to seek in a health and safety article or a joint committee's terms of reference. It is measurable, it has a published national standard behind it, and it is difficult to argue against in principle.
The timing argument, which is the one that moves things
A valid long-term test needs a minimum of 91 days, ideally during the heating season. Counting back from 30 January 2027 puts detector placement in early November 2026, and placement after the end of January pushes the measurement outside the heating season.
The usable window is roughly 1 October to the end of January. This is arithmetic rather than a legal deadline — but it means an employer who defers a decision by one quarter has in practice deferred it by a year.
That is the single most useful thing to put in front of an employer who is sympathetic but slow. It is not a threat and it is not arguable.
If the question is ignored
Try the cooperative route properly first. Most of these resolve at the committee, and an employer who is given a reasonable opportunity to respond usually does. Document the ask, the date and the response.
If it is ignored or repeatedly deferred:
- Federally regulated: a complaint may be made directly to the Labour Program at Employment and Social Development Canada, and it can result in an inspection. A worker is not required to raise it with the employer first.
- Provincially regulated: the equivalent provincial or territorial health and safety authority — the CNESST in Quebec — with the general duty as the basis.
- Federal departments and agencies: radon test results and related correspondence are records subject to the Access to Information Act.
Order matters. Escalating before the employer has had a fair chance to respond usually costs more than it gains, and the documented sequence is what makes an escalation credible.
Materials you can hand out
- Radon at work: a guide for workers and health and safety committees — written for the members you represent rather than for you. There is a printable version linked from that page. Free to reproduce.
- The legal brief — the statutory position set out section by section, with a PDF. Useful when someone asks you to prove the mechanism you are describing.
- 603,000 Canadian workers are exposed to radon — the peer-reviewed evidence that the most affected occupations are office and education roles.
Common questions
Can a representative require an employer to test?
Not directly. A committee can recommend, and in federally regulated workplaces an employer must respond in writing within a defined period. Where a hazard investigation is triggered, specific obligations follow. In provincial jurisdictions the general duty is the basis, and there is no numeric radon limit anywhere in Canada.
What if the employer says it is not required?
For provincially regulated employers that is accurate. The follow-up is not about obligation but about identification: the hazard has now been raised, and general duty provisions are chiefly concerned with what an employer does once it knows.
Is one test per building enough?
No. One detector in each occupied ground-contact room, one per 200 m² in larger areas, plus quality-control detectors. A single reading for a whole building is not a compliant measurement.
What about members who work from home?
A separate question with a different answer, and worth keeping separate so it does not muddy the workplace ask. See work from home: who pays to test for radon.
Does the employer have to share the results with us?
In federally regulated workplaces the employer must provide the committee with hazard-assessment reports, and the written control procedure must be readily available to employees. Provincial requirements vary, but a request for the report is reasonable in any jurisdiction.
What we can help with
RadonTest.ca supplies long-term radon test kits and laboratory analysis across Canada. We do not perform mitigation and we earn nothing from what a result says, which is why we can write a document like this one.
Practical things we are happy to do at no cost: tell a representative or an employer how many detectors a given building actually needs, so nobody is arguing about scope in the dark; provide the printable worker guide in English and French for distribution; and answer a question about whether a test that has already been done meets the protocol.
Email support@radontest.ca. If a union wants copies of the worker guide for a set of worksites, say how many and where, and we will sort it out — that is a distribution question rather than a sales call.
Read next
The guide for workers and committees · What a compliant record contains · Rules by province · The legal brief
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. This page describes publicly available regulatory information and is not legal advice. Free to reproduce and distribute with attribution.
Sources
Brobbey A, Rydz E, Fenton S, Demers PA, Ge CB, Peters CE. “Characterizing occupational radon exposure greater than 100 Bq/m³ in a highly exposed country.” Scientific Reports 2022;12:21323.
Canada Gazette, Part II, Vol. 160, No. 3 — SOR/2026-10; Canada Occupational Health and Safety Regulations (SOR/86-304), ss. 10.4, 10.5, 10.6, 10.26; Canada Labour Code, Part II; Employment and Social Development Canada, occupational health and safety compliance; Health Canada, Guide for Radon Measurements in Public Buildings; C-NRPP.