What is a Designated Substances Survey?
A mandatory pre-demolition or pre-renovation survey under Ontario's Occupational Health and Safety Act that identifies the presence and location of asbestos, lead, PCBs, mercury, and other designated substances in a building.
A Designated Substances Survey is the required assessment of a building scheduled for demolition or major renovation to locate and document hazardous materials regulated under Ontario's Occupational Health and Safety Act (OHSA). The survey identifies asbestos, lead-based paint, polychlorinated biphenyls (PCBs), mercury, and other designated substances that pose health risks if disturbed during construction work.
Before demolition or renovation can legally proceed in Ontario, a qualified surveyor must inspect the property to determine what designated substances are present, in what form, and where they are located. This information becomes essential for safe removal and disposal. If hazardous materials are found, they must typically be abated by licensed contractors before general demolition begins. The survey also informs workers, contractors, and site supervisors of the specific hazards they may encounter.
The requirement exists because exposure to these materials during uncontrolled demolition or renovation can cause serious health effects including respiratory disease, cancer, and neurological damage. A thorough Designated Substances Survey protects workers on site, minimizes environmental contamination, and ensures the project complies with provincial regulations. Many contractors and building owners use survey results to plan their project timeline and budget for hazmat abatement services before general construction work begins.