Summary
Radon isn’t just a residential concern—it can also pose serious health risks in workplaces. Office buildings, warehouses, retail spaces, and industrial facilities across Ontario may have elevated radon levels. This post explains why business owners should test for radon, what their responsibilities are, and how to protect employees and customers alike.
Radon Is a Workplace Health Issue
Radon is a naturally occurring radioactive gas that enters buildings from the soil. Because it is invisible and odourless, it can accumulate indoors without detection. Long-term exposure is the second leading cause of lung cancer in Canada, and workplace exposure contributes to overall lifetime risk.
Employees can spend 8–10 hours per day inside a building. If radon levels are elevated, that exposure adds up quickly—especially in ground-level or below-ground workspaces.
Workplaces Most at Risk for Radon Exposure
Certain commercial and industrial environments are more susceptible to radon accumulation, including:
Office Buildings
Especially those with:
- Basements or underground parking
- Sealed building envelopes for energy efficiency
- Limited natural ventilation on lower floors
Warehouses & Industrial Facilities
Large slab-on-grade structures can draw radon through:
- Cracks in concrete floors
- Expansion joints
- Utility penetrations
Retail & Service Spaces
Shops, clinics, and restaurants located at or below ground level may unknowingly expose staff and customers to elevated radon.
Employer Responsibilities in Ontario
Ontario does not currently mandate radon testing in all workplaces, but employers still have legal and ethical responsibilities under existing health and safety legislation.
Occupational Health & Safety Act (OHSA)
Under OHSA, employers must take reasonable precautions to protect workers from known hazards. Radon is recognized by Health Canada as a carcinogen, meaning failure to address elevated levels could be considered negligence.
Duty of Care
Even without explicit radon regulations, employers have a duty to:
- Identify potential health risks
- Take corrective action when hazards are identified
- Provide a safe working environment
Proactively testing for radon demonstrates due diligence and reduces liability.
How to Test for Radon in the Workplace
Radon testing in commercial spaces should follow Health Canada’s guidelines:
- Test all regularly occupied rooms at or below ground level
- Use long-term tests (90+ days) for accurate exposure assessment
- Place tests during fall or winter when radon levels are typically highest
For larger buildings, testing multiple locations may be required to account for airflow and structural differences.
Read more about Radon Testing for Commercial Properties.
What If Radon Levels Are High?
If testing shows radon levels above 200 Bq/m³, mitigation should be implemented.
Common Workplace Mitigation Methods
- Sub-slab depressurization systems
- Sealing foundation cracks and entry points
- Adjusting HVAC systems to reduce negative pressure
Professional mitigation performed by a C-NRPP-certified radon professional can reduce radon levels by 90% or more with minimal disruption to operations.
Read more about what happens if Radon levels are high.
Why Proactive Testing Makes Business Sense
Beyond health protection, radon testing benefits businesses by:
- Reducing long-term liability
- Supporting employee well-being and retention
- Demonstrating commitment to workplace safety
- Aligning with best practices in occupational health
In many cases, the cost of testing and mitigation is minimal compared to the potential legal, financial, and reputational consequences of inaction.
Creating Safer Work Environments
Radon exposure is preventable. By testing workplaces and addressing elevated levels, business owners can protect employees, comply with safety expectations, and foster healthier indoor environments.
