Is silica dust from grinding mortar a concern on Ottawa jobs?

Yes, silica dust from grinding and cutting mortar is a regulated workplace hazard in Ontario, not just a nuisance. Under O. Reg. 490/09, silica is a designated substance, and tuckpointing and surface grinding, along with dry mortar removal with an electric or pneumatic cutting device, are classified as Type 2 operations under the Ontario silica guideline.

Controlling exposure is the employer's duty to its workers. Before work starts, ask the crew how they plan to manage dust: wet cutting, dust extraction attached to the grinder, and appropriate respirators are the kinds of controls worth asking about. Ask how they will protect the rest of the site, including windows, HVAC intakes and neighbouring surfaces.

There is also a question of who bears responsibility for identifying designated substances before a project begins. The Occupational Health and Safety Act (s.30(1)) says an owner shall determine whether any designated substances are present before beginning a project. How that section applies when an owner-occupier hires a contractor for home renovation work is unverified in our sources, so raise it with the contractor before work starts.

Before work begins, ask for a written contract that names the dust controls along with the full scope and price.