Ontario · O. Reg. 490/09
Designated Substance Survey (DSS)
Identifying hazardous substances in building materials before demolition, construction or renovation begins — required by the Occupational Health and Safety Act to protect the workers who will disturb them.
- Regulation
- O. Reg. 490/09under the Occupational Health and Safety Act
- Required before
- Demolition, renovation & repairSection 30, OHSA
- Common in
- Pre-1980s buildingswhere regulated materials were widely used
- Deliverable
- Inventory & reportsite inspection, sampling, lab analysis
What a designated substance survey is
The purpose is to identify dangerous substances in construction materials that could be released into the air during demolition or removal work.
We provide Designated Substance Surveys to comply with Section 30 of the Occupational Health and Safety Act and Ontario Regulation 490/09. Under this legislation, designated substances and other hazardous building materials must be identified, removed, handled and disposed of in a specific manner to protect the safety of workers and building occupants.
These studies are typically required before demolition, construction, renovation and repair projects. They matter most for buildings constructed before the early 1980s, when many of the materials in common use contained one or more of these substances and are therefore more likely to still be present.
The survey typically involves a site inspection, collection of bulk samples from suspect materials, laboratory analysis, and a report of the results with recommendations for safe handling, removal or disposal — the document contractors need before tendering the work.
Owners are required to identify designated substances and provide the list to prospective contractors before work begins, so the survey has to be completed on the front end of a project rather than discovered part-way through.
The eleven designated substances
Regulated under O. Reg. 490/09. Asbestos, lead, mercury and silica are the four most commonly found in building materials.
Common questions
Designated Substance Survey Questions
What is a designated substance?
One of eleven substances regulated under Ontario Regulation 490/09 because of their potential to harm workers: acrylonitrile, arsenic, asbestos, benzene, coke oven emissions, ethylene oxide, isocyanates, lead, mercury, silica and vinyl chloride.
Which buildings need a survey?
Primarily buildings constructed before the early 1980s, when many construction materials contained these substances. Asbestos, lead, mercury and silica are the four most commonly found in building materials specifically.
When is a DSS legally required?
Before demolition, renovation or repair projects, under Section 30 of the Occupational Health and Safety Act. The owner must identify designated substances and provide the list to prospective contractors before work is tendered.
What does the survey involve?
A site inspection, collection of bulk samples from suspect materials, laboratory analysis, and a report of the results with recommendations for safe handling, removal or disposal.
What happens if a survey is skipped?
Disturbing a designated substance without knowing it is present exposes workers and occupants to real health risks and exposes the owner to regulatory liability under the Act.
Planning a Demolition or Renovation?
Send us the property address and the scope of work — we'll confirm what needs surveying and reply with a fixed quote, usually within one business day.