Overview: Making Sense of Ontario’s Designated Substances Regulation
Managing industrial, commercial, or institutional (ICI) properties in Ontario comes with a legal responsibility obligation under the Occupational Health and Safety Act (OHSA) to protect workers from hazardous material exposures. One of the most significant regulatory requirements for hazardous materials management in Ontario workplaces is Ontario Regulation 490/09 – Designated Substances, enacted under the OHSA.
This regulation establishes strict exposure limits, assessment requirements, and mandatory control programs for 11 substances recognized as posing significant occupational health risks. Employers must determine whether designated substances are present in the workplace and ensure that worker exposure is assessed and controlled in accordance with the regulatory requirements..
Common designated substances include:
- Asbestos
- Silica
- Lead
- Mercury
- Isocyanates
- Arsenic
- Benzene
- Vinyl chloride
- Coke oven emissions
- Acrylonitrile
- Ethylene oxide
These substances may occur in building materials, equipment, or industrial processes, particularly in facilities constructed or renovated prior to the earl 1990, as well as in various manufacturing and maintenance processes.
To remain compliant, employers must understand whether designated substances are present—and if so, how to manage them safely.
The first step is conducting a Designated Substance Survey (DSS).
Learn more about how THEM can help: Designated Substance Surveys by T. Harris Environmental Management Inc.
Why This Regulation Matters to the ICI Sector
For property managers, facility owners, and operations leaders across the industrial, commercial, and institutional (ICI) sectors, understanding O.Reg. 490/09 is essential to keeping people safe and projects compliant.
These workplaces frequently contain legacy materials or ongoing operations that can involve designated substances. Examples include:
- Lead-based paint and coatings in older facilities
- Silica in concrete work or masonry maintenance
- Mercury in thermostats, gauges, or lighting
- Isocyanates in spray foam insulation and industrial coatings
Failing to identify or control these hazards can result in:
- Work stoppages or project delays during renovations or demolitions
- Orders or enforcement actions from the Ministry of Labour, Immigration, Training and Skills Development (MLITSD)
- Increased liability during property transactions or lease agreements
- Occupational health risks to workers.
By addressing these risks early through a Designated Substance Survey, you can plan upgrades, renovations, or maintenance work confidently—without unexpected compliance setbacks.
Employer Responsibilities Under O.Reg. 490/09
Ontario Regulation 490/09 applies to any workplace where designated substances are present, produced, processed, used, handled, or stored. Employers must take reasonable precautions to protect workers by:
- Identifying designated substances in the workplace.
- Assessing the potential for worker exposure.
- Controlling exposure using engineering, administrative, and personal protective measures.
- Maintaining records of assessments, exposure results, and control measures.
- Training supervisors and workers on the health effects and safe handling of designated substances.
- Reviewing and updating control programs as processes or building conditions change.
Even if your company does not actively use these materials, older buildings, maintenance activities, or tenant operations can still trigger the regulation’s requirements.
The First Step: Conducting a Designated Substance Survey (DSS)
A Designated Substance Survey is often an an important first step in determining whether designated substances may be present in a facility. The survey identifies the potential presence and locations of designated substances within building materials, equipment, or operational processes.
When You Need a DSS
- Before renovations, demolitions, or major maintenance projects
- When acquiring or leasing an existing property
- As part of a due-diligence review or ongoing health and safety program
What a DSS Includes
A typical survey involves:
- A site inspection by qualified environmental consultants
- Sampling and laboratory analysis to confirm the presence of designated substances
- A comprehensive report summarizing findings, locations, and recommendations for safe management or removal
Quick Compliance Checklist
Use this high-level checklist to assess your readiness under Ontario Regulation 490/09.
| Step | Compliance Action | Status |
| 1 | Identify potential designated substances in your facility | ☐ |
| 2 | Conduct a Designated Substance Survey (DSS) | ☐ |
| 3 | Assess worker exposure and control methods | ☐ |
| 4 | Develop or update your control program | ☐ |
| 5 | Maintain documentation and training records | ☐ |
| 6 | Review and update the assessment periodically | ☐ |
If you’re missing any checks, THEM’s specialists can help you close the gap quickly and cost-effectively.
Next Steps for Facility and Property Managers
If your facility was built before 1990, involves manufacturing processes, or has not been recently assessed for hazardous materials, now is the time to act.
A Designated Substance Survey is a proactive way to:
- Reduce liability and ensure worker safety
- Support project planning and budgeting
- Demonstrate due diligence and regulatory compliance
Why Choose THEM
With over 45 years of environmental consulting experience, T. Harris Environmental Management Inc. (THEM) has completed thousands of surveys for ICI clients across Ontario and Quebec.
Our experts combine technical precision with practical recommendations, ensuring your facility meets regulatory standards efficiently and safely.
A Designated Substance Survey from THEM provides clarity, compliance, and confidence.
Learn more about our DSS services →