A confined space is defined as a place

  • that is partially or fully enclosed
  • that is not both designed and constructed for continuous human occupancy, and
  • where atmospheric hazards may occur because of its construction, location, or contents, or because of work that is done in it.

All three criteria have to be met before a space is defined as a confined space.

confined space

Hazards in confined spaces can be categorized as either physical hazards or atmospheric hazards.

Physical hazards often present a greater danger inside an enclosed space than they do outside. Examples include:

  • Noise and vibration
  • Temperature extremes
  • Cramped work spaces
  • Poor access or exit
  • Rotating or moving equipment
  • Electrical hazards
  • Uncontrolled movement of liquids and solids
  • Reactive or corrosive residues
  • Slick or wet surfaces
  • Lighting

Dangerous atmospheres have killed those working in confined spaces as well as those attempting rescue. Atmospheric hazards include:

  • flammable, combustible, or explosive atmosphere
  • toxic atmosphere
  • oxygen-deficient atmosphere
  • oxygen-enriched atmosphere

Hazard Assessment

Before each time that a worker enters a confined space, a competent worker must perform a written hazard assessment. The hazard assessment must take into account

  • the hazards that may exist in the confined space
  • the hazards that may develop while work is performed inside the confined space
  • general safety hazards in the confined space.

Confined Space Program

Before letting a worker enter a confined space, the employer must develop and maintain a written confined space program meeting the requirements of the Confined Spaces Regulation (O.Reg. 632/05).

In the case of a workplace that is not a project, the confined space program must be developed and maintained in consultation with the joint health and safety committee or the health and safety representative.

The confined space program can apply to one or more confined spaces. Program elements must include:

  • a method of recognizing each confined space
  • a method for assessing the hazards to which workers may be exposed
  • a method for developing plans for controlling the hazards
  • a method for training workers
  • an entry permit system setting out measures and procedures to be followed when working in a confined space.

Training Courses




Safety Talks


Health and Safety Manual