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Managing confined space hazards

As an employer, you must take the following five steps to reduce the risks association with confined spaces hazards in your workplace:

The first step involves identifying confined spaces and creating a written inventory of the confined spaces at your workplace. Determining whether or not a space is a confined space is not always easy. For example, flat-bottomed bins are generally considered a confined space. However, you may not have to treat them as confined spaces if they have a large, door-like entry at ground level which does not restrict access or exit in an emergency, and the bin is empty.

Get help identifying confined spaces

There are qualified persons with training and experience in recognizing, assessing, and controlling the hazards of confined spaces. A qualified person is required for:

  • Determining the hazards for each confined space
  • Developing safe work procedures before workers enter confined spaces
  • Testing the atmosphere in a confined space
  • Developing rescue procedures

Many workers don't realize they are entering a confined space. You must ensure all your workers know where confined spaces are located. Posting signs or notices at confined space entrances prohibiting unauthorized persons from entering will decrease the chance a worker accidentally enters a confined space.

Signs and notices should:

  • Be clear, visible, and written in the languages used by your workers
  • Clearly state that the area is a confined space and only authorized people may enter

Make sure to secure points of entry with locks. Or, take steps to fence or guard the area to prevent mistaken or unauthorized entry. Here are some things to remember:

  • Use locks on all covers, portholes, and doors that provide access. A lock may not be required if a cover or lid is bolted in place and requires tools for removal, or if the cover or lid is heavy enough to require tools or equipment to be moved.
  • Pits or lagoons must have at least a barrier or guardrails around the sides. Lock any gates in the barriers or guardrails. Fill the space between the ground level and the top rail of guardrail systems with heavy mesh fencing or similar material to prevent anyone from entering the hazard area through spaces between the guardrails. Post signs and notices on all gates and at intervals along the perimeter barriers or guardrails. Make sure signs and notices are visible to anyone approaching the area.
  • Inspect access points regularly (at least once per month) to ensure they are secure, that signs are legible, and sign visibility is not hidden by vegetation, materials, or equipment.

A hazard assessment for each confined space must:

  • Consider conditions that may exist before workers enter (such as location, configuration, or use of space).
  • Consider conditions that may be present while work is being conducted in the space (e.g., cleaning, painting, or welding).

Hazard assessments are required for all confined spaces in your workplace. These must be prepared by a qualified person with training and experience in recognizing, assessing, and controlling confined space hazards. If you don't have this training, you must hire a qualified person to prepare the hazard assessment.

Some of the most common hazards in confined spaces are:

Hazard Risk(s) Potential source(s)
Oxygen — too little or too much
  • Too little can cause brain damage
  • Too much increases risk of fire or explosion
  • Rusting metal can use oxygen
  • Biological activity (moulds and bacteria) can use oxygen
Toxic gases and vapours (hydrogen sulfide, methane, carbon monoxide, carbon dioxide, solvent vapours)
  • Dizziness, loss of consciousness, permanent damage to health, death
  • Liquid manure or compost
  • Work activities (painting, welding)
Explosions (gases, grain, or combustible dust)
  • Fires or explosions
  • Fuel aerosol products
  • Inadequate ventilation
  • Dust accumulations
Biological hazards (bacteria, mould, spores, allergens)
  • Mild reactions (coughing, sneezing) to severe immune reactions
  • Compost manure or other materials
  • Mouldy materials
Entrapment and engulfment
  • Buried or trapped by a collapsed "bridge" or "shoulder" (materials with empty spaces)
  • Trapped or crushed when material is discharged into a bin or hopper
  • Bins and hoppers for storing grain or feed
Moving parts of equipment and machinery (mixers, augers, rotating tanks)
  • Physical injuries
  • Accidental startup of equipment
  • Unexpected movement of equipment that has not been locked out and de-energized
  • Sharp edges of equipment
Electrical shock
  • Electrocution
  • Explosion
  • Defective extension cords, welding cables, and other electrical equipment, especially in wet conditions
Substance entering through pipe
  • Drowning from liquids (milk, liquid manure)
  • Being trapped, crushed, or buried by solids (grain, feed)
  • Being burned (steam)
  • Piping or lines connected to a confined space
Temperature extremes
  • Working in very hot or cold confined spaces
  • Hearing loss
  • Noisy equipment

  • Flooding
  • Existing liquids in tanks, ponds, and pits, if workers fall into structures

Educate workers about confined spaces. Be sure they know what a confined space is. Make it clear they must not enter any confined spaces without proper training, equipment, and permission.

Ongoing communication with workers is important because conditions can change over time and new hazards can develop. You should:

  • Talk to workers about the confined spaces at your workplace. Inform them about specific spaces and the hazards those spaces may contain.
  • Explain safety signage and why some spaces have been locked to prevent unauthorized entry.
  • Ask workers to tell you if they find new confined spaces or possible hazards.
  • Encourage workers to tell each other about possible hazards and to watch out for each other. If a worker sees someone entering a confined space without authorization, he or she should stop that person from entering the space or immediately report it to a supervisor.

Some confined spaces require entry for inspection, maintenance, or repairs. If entry is required, list the reasons why on your inventory. Here are some ways to make confined spaces safer:

Find a way to do the work outside the space:

  • Use a portable vacuum to remove remaining material from a bin without entering a confined space.
  • Consider permanently moving equipment to a new location outside the confined space.
  • Consider realigning equipment so it can be removed from the space for repair and then placed back into the space. For example, consider installing a removable agitator system in a manure pond so workers won't have to enter the pond when repairs are necessary.

Modify the space to make it safer:

  • Enlarge the opening
  • Install another opening at the bottom, if the space can only be accessed from the top

Before a confined space is ready for entry, you must put together a confined space program that includes safe entry and work procedures. Hiring a qualified contractor is a legitimate and acceptable way to ensure worker safety and to delegate the requirement for specialized training and equipment.

It is your responsibility as the employer to ensure:

  • Contractors are competent to enter and work in confined spaces.
  • Contractors are following safe work procedures, as prepared by a qualified person.
  • That a confined space program and safe entry procedures are in place before work begins in the confined space.