Carbon monoxide gas (CO) can be deadly.  According to statistics from the Alberta Government, CO was the cause of 90 fatalities in the province between 1990 and 2002¹.  Several of these fatal incidents were work related.  Many more deaths from carbon monoxide have occurred across Canada.

Carbon monoxide is a colourless and odourless gas.  It’s usually generated from fuel-burning or combustion processes, but is also produced when certain organic chemicals break down.

CO reduces the body’s ability to take up oxygen.  CO binds to the hemoglobin in blood and forms a complex known as carboxy-hemoglobin (COHb), which blocks oxygen uptake.  This can lead to a variety of health effects, including: headaches, dizziness, nausea, visual disturbances, loss of muscle coordination, unconsciousness, coma or death.  Symptoms are not always present before death, which is why CO is often called “the silent killer”.   Some research also suggests that long-term exposure to low concentrations of CO may be harmful.

Work-Related Carbon Monoxide Fatalities

The first step in preventing CO poisoning in the workplace is to identify situations where carbon monoxide exposure is possible.  Make sure your hazard assessments and workplace inspections include a search for potential CO sources.  Work processes and equipment that rely on combustion of fuels should always be suspect, especially if they’re used in enclosed spaces.  Here are a few examples:

• Forklifts (propane, diesel), which often enter enclosed spaces such as shipping containers or small storage rooms
• Floor polishing machines
• Ice making equipment
• Construction heaters and torches
• Kilns
• “Hot work” such as welding, cutting and burning
• Furnaces, boilers and non-electric space heaters and any areas serviced by, or adjacent to them
• Cooking equipment (e.g., ranges, grills, barbeques)
• Wood burning processes
• Automobiles and other mobile equipment
• Plastics, forging, ceramic, petroleum, steel and waste management industries.

 Carbon monoxide poisoning usually occurs in poorly ventilated areas.  It follows, then, that work spaces should be thoroughly ventilated.  Mechanical ventilation should be used wherever possible.  This includes plentiful “combustion air” for fuels to burn as thoroughly as possible and exhaust ventilation to remove the build-up of carbon monoxide and other emissions.

The installation, use, and maintenance of equipment are also important to prevent dangerous carbon monoxide exposures.  Equipment should be installed and maintained by qualified persons, in many cases a licensed gasfitter or other certified technician.  Regular inspections and maintenance will keep equipment operating properly and reduce unwanted, dangerous emissions.

Carbon monoxide exposure can also be prevented by following practices such as these:

• Operate all equipment in accordance with manufacturers’ instructions.
• Install CO detectors / alarms, some of which can signal exhaust fans to start when CO concentrations reach trigger levels.  Use only approved devices and seek professional help to properly locate and install CO detectors.
• Inspect and clean chimneys, flues, space heaters and other heating equipment.
• Equip vehicle maintenance and storage garages with exhaust hoses.
• Direct all exhaust air to the outdoors.
• Educate your workforce on the dangers of CO exposure, symptoms and first aid.
• Review material safety data sheets to identify products that can produce carbon monoxide emissions.
• Encourage workers to report unsafe conditions, near misses, and other incidents.

 Useful References:

1.     “Alberta Accidental Carbon Monoxide Deaths 1990-2002”, Office of the Chief Medical Examiner, Alberta Justice, December 31, 2002.

2.     “Alert: Carbon Monoxide Poisoning in Enclosed and Semi-Enclosed Worksites”, Alert 05, Ontario Ministry of Labour, November 1994 http://www.labour.gov.on.ca/english/hs/alerts/a05.html

3.     “Carbon Monoxide at the Work Site”. Bulletin CH031, Alberta Human Resources and Employment, Revised May 2004.

4.     Resources – Carbon Monoxide, Worksafe BC Website, http://www2.worksafebc.com/Topics/IndoorAir/CarbonMonoxide.asp

5.     “Carbon Monoxide – The Silent, Cold Weather Killer”, American Industrial Hygiene Association, http://www.aiha.org/content/accessinfo/consumer/carbonmonoxide.htm