Designated Substance Survey (DSS)

A Designated Substances Survey (DSS) is a vital requirement in Ontario for any property undergoing renovation, demolition, or redevelopment. Mandated by the Occupational Health and Safety Act (OHSA), a DSS identifies and documents the presence of hazardous materials known as designated substances — including asbestos, lead, mercury, silica, arsenic, and others.

These substances, if disturbed during construction activities or if already in poor condition (deteriorated/damaged) onsite, can pose serious health and safety risks to workers, occupants, and contractors. A DSS helps you meet legal requirements, manage and mitigate risks, and avoid costly delays or penalties. 

You must complete a DSS: 

• Before any demolition or renovation project in Ontario 
• As part of real estate due diligence before buying, selling, or leasing a property 
• For ongoing facility safety and compliance, especially in older or industrial buildings

Failing to perform a DSS can lead to regulatory non-compliance, work stoppages, and increased liability if exposure occurs. 

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At T. Harris Environmental Management Inc. (THEM), we’ve conducted thousands of hazardous materials surveys across Ontario and Quebec. Our clients include general contractors, property managers, engineers, architects, and facility owners in cities such as Toronto, Ottawa, London, and Montreal. 

Our team includes Professional Engineers (P.Eng), Certified Industrial Hygienists (CIH/ROH), and Designated Substance Experts who are well-versed in Ontario’s OHSA regulations. Every DSS is tailored to your property and project scope, and delivered with the accuracy, speed, and professionalism THEM is known for. 

DSS Services from THEM Include: 

• Visual inspection of accessible areas 
• Sampling and analysis by accredited labs 
• Identification of all relevant designated substances 
• Risk evaluation for health and environmental impact 
• Clear recommendations for abatement or ongoing management 
• Full regulatory documentation, ready for submission to the Ministry of Labour, Immigration, Training and Skills Development (MLITSD) 
• Regulatory compliance documentation 

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