The Construction Health and Safety Program enforces Ontario’s workplace safety laws in the construction sector.

Construction is a dynamic industry made up of several primary sectors, each with subsectors. Individual activities are diverse with workplaces and workforces that change constantly. In a typical project, there can be multiple employers and up to 10 different trades and trade unions on site. These multiple-employer and multiple-union workplaces are quite different from those in other industries.

The construction sector covers both large and small firms and includes unionized and non-unionized workplaces. The workforce includes contractors, sub-contractors, both part-time and temporary workers, family members and business owners.

Most construction contractors in Ontario are small- to mid-size employers. Many construction employers have fewer than eight employees. Some construction employers have more than 100 workers often working across several projects.

Although Ontario’s construction industry is one of the safest in the world, there is a high potential for injury, given the nature and conditions of the work.

The Construction Health and Safety Program continues to work actively with its health and safety partners and external stakeholders to control and, where possible, eliminate the top hazards in each sector. The partnership also promotes compliance and the development of a strong health and safety culture in the workplace.

Legal definition of construction

Under the Occupational Health and Safety Act, “construction” includes:

  • erection
  • alteration
  • repair
  • dismantling
  • demolition
  • structural maintenance
  • painting
  • land clearing
  • earth moving
  • grading
  • excavating
  • trenching
  • digging
  • boring
  • drilling
  • blasting or concreting
  • the installation of any machinery or plant
  • any work or undertaking in connection with a project, excluding any work or undertaking underground in a mine

Legal definition of a construction project

Under the Occupational Health and Safety Act, a construction “project” includes the construction of – including any combination of – a:

  • building
  • bridge
  • structure
  • industrial establishment
  • mining plant
  • shaft
  • tunnel
  • caisson
  • trench
  • excavation
  • highway
  • railway
  • street
  • runway
  • parking lot
  • cofferdam
  • conduit, sewer
  • water main
  • service connection
  • telegraph, telephone or electrical cable
  • pipe line
  • duct or well

“Project” also refers to any work, undertaking, lands, equipment or materials used in connection with construction. The moving of a building or structure is also a project.

Asbestos abatement operations

In Ontario, asbestos operations are classified according to the level of the asbestos hazard they present. As the exposure risk increases from Type 1 to Type 2 to Type 3, additional measures and procedures are necessary to protect workers from exposure.

The sector includes three types of asbestos abatement operations:

  • Type 1 covers installing or removing of asbestos-containing products that are non-friable (that is, not easily crumbled between the thumb and fingers) or are not already crumbled.
  • Type 2 includes breaking, cutting, drilling, abrading, grinding, sanding, or vibrating non-friable asbestos-containing material using non-powered hand-held tools if the material is not wetted.
  • Type 3 includes work with either friable or non-friable asbestos-containing material that has the potential to generate high concentrations of asbestos fibers in the air.

Industrial, commercial and institutional

This includes:

  • industrial buildings (for example, manufacturing plants, industrial warehouses)
  • commercial buildings (for example, retail stores, malls)
  • institutional buildings (for example, schools, health care institutions)
  • above ground mining plants (for example, gravel processing facilities)


The residential sector is characterized by multiple contractors and independent operators.

This includes:

  • high-rise buildings (for example, rental apartments, condominiums)
  • low-rise residential housing (for example, single homes, townhouses)
  • renovations, reconstruction or additions to existing homes (for example, upgrading living space, re-roofing)
  • in-fill housing (for example, new home constructed between existing housing)


This includes:

  • highway and road construction (for example, new roads, rebuilding existing highways)
  • infrastructure or large public works projects (for example, widening an intersection,  replacement of community sidewalks, bridge construction (for example, highway overpass, movable bridge over a waterway)
  • asphalt paving (for example, new roads, resurfacing)


This includes:

  • sewer and water main (for example, new or existing subdivisions)
  • trenching (for example, water runoff ditch, pipeline installation)
  • excavations (for example, reservoirs)
  • caisson and cofferdam construction (for example, concrete dams, bridge piers)
  • shafts (for example, sewage or water tunnel)
  • tunnelling (for example, traffic diversion, pedestrian passageway)
  • subway and railway (for example, tracks, access platforms)


This includes:

  • underground utility infrastructure systems (for example, natural gas lines, cable services)
  • power electrical distribution lines (for example, transmission systems, electrical towers)
  • renewable energy (for example, hydroelectric generating systems from flowing water, geothermal energy systems from the earth’s heat, wind turbines, solar power)

Window cleaning

This includes window cleaning services for buildings where a worker may fall a vertical distance of 3 metres or more (for example, commercial services, new residential construction project, high rise apartments).

Other construction

This includes:

  • construction that is not covered under the other subsectors (for example, silo construction)
  • moving buildings or structures (for example, moving historical buildings or monument)
  • demolition (for example, damaged structure)


A “diving operation” means work performed under water by divers and includes work performed on the surface in support of divers.

This includes:

  • inspections (for example, dams, bridge foundations)
  • investigations (for example, submersed pipelines)
  • excavation (for example, boating waterway)
  • construction or alteration (for example, bridge foundations, underwater welding or concreting)
  • repair or maintenance (for example, equipment, machinery, structures, ships)
  • services (for example, scientific research, aquaculture support, emergency services)
  • environmental (for example, reduction or removal of spills)
  • salvage operations, (for example, recovery of sunken property)