Case Study: Carbon Monoxide Incidents (2007 - 2015)

Carbon monoxide (CO) is a poisonous gas that is colourless, odourless and tasteless. If inhaled in sufficient quantities, CO can interfere with the body’s ability to absorb oxygen. At low concentrations, symptoms of CO poisoning present similar to flu symptoms: headaches, nausea, fatigue and dizziness. In higher concentrations or prolonged exposure, symptoms can worsen and cause loss of consciousness and death.

Carbon monoxide exists naturally in the atmosphere in small concentrations and is also a combustion by-product of carbon-based fuels. CO is produced when the combustion of a carbon-based fuel is incomplete, usually due to insufficient oxygen during the combustion process. Balanced fuel and air mixtures can minimize the amount of CO produced during combustion, while venting combustion gasses to the atmosphere prevents CO build-up from occurring in enclosed spaces.

Basic Combustion Diagram

 

Basic Illustration of a Residential Appliance

 

Technical Safety BC observed incidents involving regulated equipment that resulted in CO poisoning causing fatalities and other injuries. CO poisoning incidents are usually a result of at least one of the following two conditions being present:

  1. A failure to effectively vent the products of combustion away from enclosed, occupied spaces.
  2. Excess CO being produced by fuel-burning appliances.

This case study provides an overview of the incidents involving CO that were reported to and investigated by safety officers occurring from January 1, 2007 to December 31, 2015. It is important to note that Technical Safety BC does not regulate all fuels that produce CO; therefore, occurrences involving fuels not regulated by Technical Safety BC are not considered in this review.

Incident  Investigations

A total of 84 carbon monoxide incidents were reported and investigated between 2007 and 2015. These incidents resulted in nine fatalities and 161 non-fatal injuries. A list of the incidents is included in Table 2, at the end of this document.

There is a variation in the number of carbon monoxide incident investigations from 2007 to 2015. Figure 4 shows the distribution of CO incident investigations by month. Most CO-related incidents occurred from October to April.

Carbon Monoxide Incidents Investigated by Month and Year

 

 

During this nine-year period, CO incidents resulted in nine fatalities and 161 non-fatal injuries. In June 2008, one incident resulted in 27 employees at an industrial facility where the investigation stated the employees being taken to hospital and found to have CO poisoning. In 2014, one incident was reported to have affected 15 people who went to hospital after some residents reported experiencing symptoms of CO exposure.

Most incidents occurred in residences and involved residential furnaces, boilers or water heaters. Each investigation identified at least one appliance that produced, or may have produced, carbon monoxide.

Note 1: Some investigations identified multiple appliances that may have produced CO, yet did not confirm which was most likely the CO source; therefore, the total number of appliances exceeds the number of events. For example, there were 38 incidents that identified furnaces for potential involvement. In 30 of these 38 cases, the investigation confirmed that the furnace was the source of excess CO. In the remaining eight cases, the investigation could not confirm that the furnace produced excess CO, or the investigation identified that there were other appliances (in addition to the furnace) that could have produced excess CO.

Investigation activities focus on understanding the relationship between regulated work or regulated equipment and the factors that may have contributed to the cause of the event. Factors contributing to the CO incident occurrences are summarized in Table 1. Additional details are available in Table 2.

Table 1: Summary of Factors Contributing to CO incidents 

Causes and contributing factors that attributed to the incident Qty of Events
Equipment or component failures 15
Installation issues 14
Investigations were inconclusive [Note 1] 6
Unqualified persons performing regulated work 5
Unsafe use of equipment 3
Poor air-gas ratio 2
Wind creating a downdraft 1

Note 1: Although elevated CO was observed, the investigation was either unable to determine the cause or unable to rule out the involvement of regulated equipment.

Carbon Monoxide Incident and Injury Summary

From 2007 to 2015, there were 84 incidents reported to Technical Safety BC. These incidents resulted in nine fatalities and 161 non-fatal injuries. Most CO incidents occurred from October to April. Most incidents occurred in residences and involved residential furnaces, water heaters or boilers as the source of CO, while ineffective venting and maintenance were identified as the most prevalent contributing factors.

This data highlights the importance of proper installation and maintenance of residential fuel-burning appliances and their venting systems. It also illustrates the importance of using CO detectors in homes that have fuel-burning appliances.

Carbon Monoxide Incidents (2007 - 2015) are provided via a downloadable .CSV file.

Year              Incident Data
2007 - 2015 Data Set (.csv)

Table 2: Carbon Monoxide Incident Investigations

This listing provides an overview of the incidents involving carbon monoxide (CO) that were reported and investigated by Technical Safety BC safety officers. It is important to note that Technical Safety BC does not regulate all fuels that produce CO, therefore occurrences involving fuels not regulated by Technical Safety BC are not considered in this listing. Incidents involving work or equipment regulated under the Safety Standards Act are required to be reported to the appropriate provincial safety manager.

The Province of British Columbia, however, delegated partial administration of the Safety Standards Act to a number of local governments. These local governments administer gas assessment programs for detached dwellings with gas services at a pressure of 14.0k Pa gauge or less with a total connected load for the meter of 120 kW or less and are identified in Appendix H. Gas incidents, including carbon monoxide incidents, occurring in these municipalities would be reported to the local government safety manager and may not be reported to BC Safety Authority.

Technical Safety BC receives its injury reports and descriptions from operators or first responders at the time of, or immediately following, the incident. Injuries may develop after the initial reports were made to Technical Safety BC and the long term effects of a resultant injury may not be recorded as part of the Technical Safety BC investigation.

  INJURY TYPE               EQUIPMENT        
INCIDENT DATE CITY TOTAL INJURED/ AFFECTED FATAL INJURY HOSPITALIZED/ HOSPITAL VISIT RECOMMENDED NO INJURY REPORTED BUT AFFECTED/ DISPLACED INCIDENT DESCRIPTION POSSIBLE CAUSE(S), CONTRIBUTING FACTOR(S) AND DESCRIPTIONS CAUSE CATEGORY OCCUPANCY/ PREMISE TYPE IDENTIFIED IN INVESTIGATION SOURCE OF CO POSSIBLE SOURCE OF CO GAS TYPE
17-Mar-07 Surrey 1 0 0 1 A person was exposed to CO. The person was taken to hospital but decided not to stay because there was a six hour wait; by the time the person arrived at the hospital, the person claimed he was feeling better. Defective gas appliances and associated venting. Equipment failure Residential Furnace, water heater Furnace Water heater Natural gas
11-Apr-07 New Westminster None 0 0 0 An odour was reported at a condominium building; building was evacuated. The fan belt was found to be broken, which would have caused improper venting. Combustion products could have been drawn into the makeup air in-stream and pumped into hallways. A copper sensing tube was found lying in the bottom of the switch compartment. Component failure Residential Makeup air unit Makeup air unit - Natural gas
20-Apr-07 Prince George 2 0 1 1 Gas utility responded to an odour call. Cracked heat exchanger and flame roll-out due to lack of maintenance. Lack of maintenance Residential Furnace Furnace - Natural gas
2-Jul-07 Vernon 2 2 0 0 Two people died from CO exposure. The cabin was built of tight construction with little air leakage; no combustion air brought into the cabin; refrigerator was not installed to manufacturerÕs recommendations. Incorrect installation Recreational (Cabin) Refrigerator Refrigerator - Propane
6-Jul-07 New Westminster 0 0 0 0 A person contacted his gas contractor after noticing dew-like condensation on the basement walls. About six months prior, the contractor had replaced the homeÕs hot water heater and furnace and common-vented into a masonry chimney. The contractor was not aware of the pool boiler that was located in a different area of the basement. Vent obstructed; Combustion products unable to vent Residential Pool boiler Pool boiler - Natural gas
18-Jul-07 Duncan 1 0 1 0 A person was taken to hospital and treated for CO poisoning. The heat exchanger was cracked and allowed CO to enter the circulating air stream. Component failure Residential Furnace Furnace - Natural gas
5-Oct-07 Coquitlam 2 0 2 0 Two people were taken to hospital with possible CO poisoning The roofÕs rain cap on the B-vent was changed when the house was re-roofed earlier in the year. The rain cap was replaced with the incorrect type and partially blocked the B-vent. The furnace filter was the wrong size and the door of the blower compartment was partially open. Equipment service/ replacement Residential Furnace Furnace - Natural gas
27-Nov-07 Sun Peaks 6 0 6 0 Six people were taken to hospital with CO poisoning. The boilerÕs vent termination pipe was dislodged and the boiler would continue to shut down where the pipe became dislodged. The boiler would then shutdown and Ôrecycle itselfÕ continuously. During start-up, the boiler was producing more than 1000ppm and decrease to 47ppm at high-fire. Combustion products unable to vent Residential Boiler Boiler - Natural gas
14-Dec-07 Pitt Meadows 4 0 4 0 Four people were treated for CO poisoning. The utility technician tested for CO; detected CO at the furnace. Unable to determine cause Residential Furnace - Furnace Natural gas
26-Jan-08 Denman Island 1 1 0 0 A deceased person was discovered in a burned out camperized van. It is unknown if fire was started by vehicleÕs electrical system, smoking materials, or operation of catalytic heater within vehicle. If heater was in use, CO poisoning/ impairment was possible, or heater could have ignited combustibles inside vehicle. It is possible the deceased was using the heater within the van and was Unable to determine cause Camperized vehicle Catalytic heater - Catalytic heater Propane
11-Apr-08 Vancouver 0 0 0 0 A gas odour was reported to the fire department. A tarp was temporarily installed for roof repairs. All of the B-vented appliances (gas fireplaces, boilers, make-up air units, ranges) were venting to the space below the tarp. Combustion products were trapped under the tarp where it was recirculated by roof top equipment and heating appliances. The CO then migrated throughout the building by the hall pressurization equipment. Combustion products unable to vent Commercial Fireplaces, boilers, make-up air units, ranges Fireplaces, boilers, makeup air units, ranges - Natural gas
18-Jun-08 Armstrong 27 0 27 0 Twenty-seven people were taken to hospital for CO poisoning. A Ònegative from the fan coil unitÓ caused the boiler not to vent. The amount of rust on the back of the boiler indicated the boiler had not been vented for an extended period of time. Combustion products unable to vent Industrial Boiler Boiler - Natural gas
1-Sep-08 Lumby 5 0 5 0 Five people were taken to hospital for treatment after exposure to CO. Inspection of the premise revealed one ventless propane refrigerator and one cook-top stove. There was no combustion air into the premise; the refrigerator had not been serviced for some time. The refrigerator vent was partially plugged, the burner was not burning properly as the air shutter for the burner was not adjusted properly. There were carbon deposits on the burner and air shutter. Lack of maintenance Recreational (Cabin) Refrigerator, cook top/stove Refrigerator Cook top/ stove Propane
24-Oct-08 Charlie Lake 2 0 1 1 Two people were affected by CO. Faulty mobile home gas furnace. Equipment failure Residential Furnace Furnace - Natural gas
29-Nov-08 Langley 2 0 2 0 Two people were treated for CO poisoning. A gas contractor inspected the furnace and found a crack in the heat exchanger. The heat exchanger failed due to the age of the equipment and lack of service. Lack of maintenance Residential Furnace Furnace - Natural gas
6-Dec-08 Burnaby 0 0 0 0 The utility responded to a CO alarm call. CO source was determined to be the roof top air handing unit. Three power-vented boilers were 20ft away on the same wall as the air handling unit; combustion products were drawn into the air intake. Combustion products unable to vent Residential Roof top air handing unit Roof top air handing unit - Natural gas
3-Jan-09 Surrey 0 0 0 0 A person awoke to found their residence filling with smoke. Although it was determined that the smoke originated from combustible debris left in the furnace, further investigation identified several performance issues with the furnace. The installer failed to remove the paper or cardboard at the furnace warm air plenum. The installer was not a qualified fitter and the contractor was not licensed. Regulated work by unqualified person Residential Furnace Furnace - Natural gas
30-Jan-09 Dawson Creek 4 0 0 4 A gas leak was reported to the fire department. Inspection revealed furnace was producing CO. The return air had been removed and terminated within the furnace room. The return air caused the furnace to back-vent and allowed combustion products to enter the building. Combustion products unable to vent Commercial Furnace Furnace - Natural gas
2-Feb-09 Merritt 5 0 0 5 Five people experienced effects of CO. Heat exchangers on the pool boilers were plugged due to lack of maintenance. Venting was restricted and spilled from the appliances. The door was propped in an open position, allowing vent gases/combustion products to be drawn from the mechanical room into the common pool area. Lack of maintenance Commercial Pool boiler Pool boiler - Natural gas
26-Oct-09 Surrey 3 0 0 3 Complaints of CO symptoms affecting three people. A lower and upper suite was found with gas heating appliance exhaust vents not connected to the main vent. When in operation, the applianceÕs exhaust gases would enter the dwelling. Occupants were unaware of the unsafe condition until advised by the utility technician. Condition could have existed for five months. Combustion products unable to vent Residential Hot water heater, hot water boiler - Hot water heater, hot water boiler Natural gas
27-Nov-09 Burns Lake 2 1 1 0 One person died from CO poisoning; another person was hospitalized. An exhaust power venter was improperly installed on an existing natural gas boiler. The venter was installed by a registered gas contractor approximately two months prior to the incident; the manufacturerÕs instructions were not followed. Investigation revealed that the venter ran 50% of the time while the boiler was fired; otherwise, the boiler spilled combustion products into the residence. Incorrect installation Residential Fireplace, boiler Fireplace, boiler - Natural gas
14-Dec-09 Delta 0 0 0 0 A utility technician shut down a gas furnace after a high concentration of CO was detected. (Not described) Unable to determine cause Residential Furnace Furnace - Natural gas
29-Dec-09 Kamloops 0 0 0 0 People phoned emergency services when their CO detector sounded. The installation is over 20 years old and does not meet current code requirements. The change room had the combustion air supply blocked off to prevent cold air from freezing the water lines in the room and an interior door to the building was left open. The negative pressure in the building (house) and lack of an air supply to the room caused the back-drafting. Combustion products unable to vent Residential Pool boiler Pool boiler - Natural gas
4-Jan-10 Prince George 1 0 0 1 A person experienced CO poisoning after CO detector alarms sounded. Testing found that the hot water heater was spilling combustion products resulting in an elevated CO level. The hot water heater displayed evidence of corrosion and inadequate maintenance. A passive 4Ó combustion air source was located in the equipment room in addition to the combustion air grille located in the supply plenum of the furnace. The furnace return air ducting was reasonably tight, the filter access had no cover. No indication of back-drafting at the appliance draft hoods. Lack of maintenance Residential Hot water heater, furnace Hot water heater Furnace Natural gas
15-Mar-10 Vernon 1 0 0 1 A person experienced symptoms of CO exposure. The furnace was enclosed in a small space; no combustion air. There was a 6Ó hole in the return air duct close to the burner. The lack of combustion air and large opening in the return air plenum caused a negative pressure in the furnace space, causing flame rollout and incomplete combustion, and distribution of the combustion products throughout the premise. Combustion products unable to vent Residential Furnace Furnace - Natural gas
18-Apr-10 Prince Rupert 2 0 0 2 Two people were taken to hospital for carbon monoxide poisoning. The vent was dislodged from the boiler. Combustion products unable to vent Residential Boiler Boiler - Natural gas
20-Apr-10 Chemainus 1 0 0 1 A hospital test revealed that a person had an elevated CO. The utility technician measured CO coming from the dual flame burner on a dual fuel range with a gas cook top. The dual flame burner had a glass centre. When the burner is Ôon,Õ the flame seemed to impinge on the glass, producing CO with or without a pot or pan on it. The other three burners produced 40ppm CO on start up and reduced to negligible when warm. Owner was not using the microwave exhaust fan when using the range. Combustion products unable to vent Residential Dual fuel range Dual fuel range - Natural gas
19-Aug-10 Victoria 0 0 0 0 The fire department responded to an odour call and CO detector alarm call. The gas water heater serviced three suites. The atmospheric water heater was vented into a dilapidated chimney that served the entire building. The 3Ó chimney vent connector was taped into the main chimney; no liner in the chimney. There was no combustion air into the common suite where the water heater was located. Incorrect installation Residential Water heater Water heater - Natural gas
14-Oct-10 Agassiz 1 0 0 1 Emergency services were called when a person was found unresponsive. The appliances appeared that they have not been serviced. The masonry chimney was completely plugged where the furnace connects to the vent connector. The vent connector from the furnace was partially plugged by debris from the masonry chimney. The furnace had large rust particles from the heat exchanger laying across the burner. Its is possible that the furnace heat exchanger had holes in it. Lack of maintenance Residential Furnace Furnace - Natural gas
20-Oct-10 West Vancouver 0 0 0 0 A water heater was damaged by a home made burner assembly. A person assembled a makeshift burner to keep the water hot after the utility had plugged the fuel supply. The home-made hose and burner assembly was not secured to the water heater. The orifice was not secured to the burner and was likely to have caused severe damage and/or injuries. Pets could have dislodged the orifice, which could have caused the basement to fill with propane gas. Intentional bypass of safety measures Residential Water heater, camp stove burner Water heater, camp stove burner - Natural gas
12-Dec-10 Kelowna 2 1 1 0 One person died from suspected CO poisoning. A second person was hospitalized for treatment. The furnace fan and/or dryer put the home into a negative pressure condition which caused the fireplace B-vent to down draft. The furnace duct system in the insulation space under the premise was not tightly sealed and caused a substantial negative pressure in the home when the furnace air circulation fan was operating. The fire place Incorrect installation Residential Furnace, fireplace Furnace, fireplace - Natural gas
25-Jan-11 Squamish 0 0 0 0 A rooftop heating unit developed corroded and plugged burners. Excessive debris accumulated in the combustion chamber. Lack of maintenance over time caused unit deterioration to point where critical components were corroded, holes were created. Lack of maintenance Commercial Roof top heating unit Roof top heating unit - Natural gas
30-Jan-11 Cumberland 0 0 0 0 Fire-side boiler explosion. Flue gas analysis on boiler #2 indicated the boiler was in a poor state of air-gas ratio. The boiler was producing more than 2000ppm CO at high fire. The explosion was consistent with an off-cycle combustible explosion. Poor air-gas ratio Commercial Boiler Boiler - Natural gas
4-Feb-11 Dawson Creek 0 0 0 0 Combustion products entered into a home after the flue separated. The flue collar from the flue liner separated from the base tee of the flue assembly. Combustion products unable to vent Residential Furnace, hot water tank Furnace, hot water tank - Natural gas
28-Mar-11 Vancouver 1 0 1 0 The utility responded to a gas odour call. A person was sent to hospital. Venting on unit heaters had holes due to rusting. Investigation revealed that the common venting for the unit heaters did not meet code requirements. Combustion products unable to vent Commercial Unit heaters Unit heaters - Natural gas
23-Aug-11 Surrey 0 0 0 0 On advise from the utility, a person reported an incident involving the unsafe operation of a gas water heater. Valve failed Component failure Residential Water heater Water heater - Natural gas
17-Oct-11 Prince George 4 0 4 0 Four people experienced CO symptoms The water heater was installed in 2008 but recently was experiencing pilot outages. The furnaceÕs combustion blower was not tight, the exhaust vent coupler was not tightened. There appeared to be a lack of service on the water heater and lack of combustion air. Equipment failure Residential Water heater, furnace Water heater Furnace Natural gas
5-Dec-11 Armstrong 1 0 0 1 A person experienced CO symptoms The utility found high levels of CO at the top heat grill to the fireplace. Unable to determine cause Residential Fireplace Fireplace - Natural gas
22-Dec-11 Penticton 2 0 0 2 Two people contacted the utility when their CO detector sounded. Lack of maintenance of the furnace caused the appliance to produce high levels of CO in the flue gas. Lack of maintenance Residential Furnace Furnace - Natural gas
24-Dec-11 Whalley 0 0 0 0 The utility responded to an odour call. Short B vent height results in poor stack action which occasionally results in the products of combustion from the water heaters spilling into the mechanical room. Combustion products unable to vent Residential Water heaters Water heaters - Natural gas
7-Jan-12 Langley 0 0 0 0 The utility responded to an odour call at a residence. The utility technician confirmed that the furnace was not venting correcting and spilling CO into the residence. Insufficient gas supply caused buildup of carbon within burner. The appliance was being supplied by gas found to be bypassing a gas meter shut-off valve. Equipment failure Residential Furnace Furnace - Natural gas
7-Feb-12 Langley 5 0 5 0 People felt ill in their home and contacted emergency services. Type-B vent termination cap corroded and collapsed onto the vent pipe, causing flue blockage and spillage of combustion products to spill into the residence. Vent obstructed; Combustion products unable to vent Residential Boiler, water heater - Boiler, water heater Natural gas
22-Feb-12 Kelowna 0 0 0 0 The fire department responded to a CO alarm at a residence. It appears that an unqualified technician was working on the water heater two days prior to the incident taking place. The individual was called by the owner to repair a water leak and left the water heater running knowing that Regulated work by unqualified person Residential Water heater - Water heater Natural gas
17-Mar-12 Mission 0 0 0 0 The utility responded to an odour call. Plugged vent connector; The furnace draft hood outlet was found plugged with fibreglass insulation. The person advised the GSO that a new microwave and exhaust fan was installed. The B-vent (located above the furnace) appeared that it had been relocated from its original location. A ÔballÕ of fibreglass insulation was found in the vent connector. It is possible that the previous owner plugged the connector to prevent renovation debris from entering the furnace when it was moved, and had forgotten to remove the debris. Vent obstructed; Combustion products unable to vent Residential Furnace - Furnace Natural gas
1-May-12 Osoyoos 1 0 1 0 A person was sent to hospital for CO exposure. Appliance installed with non-compliant venting and air requirements. Incorrect installation Residential Furnace - Furnace Natural gas
25-Jul-12 Salmo 3 0 1 0 Three people were treated at hospital for CO exposure. It was not determined why the furnace was producing CO. The vent and chimney were clear; combustion products were spilling from the draft diverter. The furnace condition was poor; the heat exchanger appeared to be corroded. Cracks in the heat exchanger were present. Unable to determine cause Residential Furnace Furnace - Natural gas
29-Aug-12 Nelson 0 0 0 0 The utility responded to a CO alarm at a residence. ÒWater heater over-firedÓ; ÒThe home is at the base of a mountain there were high winds and a cool down draft coming off the mountain, coupled with tall cedar trees surrounding this home providing a high probability of a down draft at the gas vent. I suspect that the down drafting caused the products of combustions to spill into the home.Ó Wind created down-draft Residential Water heater Water heater - Natural gas
20-Oct-12 Smithers 0 0 0 0 The utility responded to an odour call. Appliance venting was not finished per regulation. The B vent was not insulated and framed per regulation. Also, the boiler could not vent properly because the hot water tank was replaced with an electric tank which Òcompounded the stack action.Ó Venting Òwas not finished per regulationÓ Residential Boiler Boiler - Natural gas
24-Oct-12 Vancouver 0 0 0 0 The utility responded to an odour call. The exhaust fan was not working properly. Equipment not operating Commercial Stock pot Stock pot - Natural gas
31-Oct-12 Abbotsford 0 0 0 5 People were exposed to CO. Unqualified, not knowledgeable person performing regulated work. Regulated work by unqualified person Residential Furnace Furnace - Natural gas
29-Nov-12 West Vancouver 0 0 0 0 An exhaust vent had dislodged, allowing combustion products to be vented into the residence. Pipe connection dislodged due to the sealant failing to adhere the plastic. The venting was well supported, and there is evidence that both the recommended primer and adhesive was used. It is possible that the elbow was impacted by a person or thing in the area leading to the disconnection. It is also possible the adhesives were subject to some kind of contamination or compromise at the time of application that allowed them to fail Venting pipe connection dislodged Residential Water heater, furnace Water heater, furnace - Natural gas
16-Jan-13 Salmon Arm 0 0 0 0 The utility responded to a CO alarm at a single-family residence. Down-drafting appliance vent and obstructed flue. The investigation revealed that when the dryer or kitchen fan was turned on, the furnace and hot water heater would spill flue products. Combustion products unable to vent Residential Furnace, Hot water heater Furnace, hot water heater - Natural gas
18-Jan-13 Salmon Arm 5 0 5 0 The utility responded to a CO alarm at a multi-family residence. The utility technician found 200ppm ambient CO in the residence. A 20-year old high efficiency furnace had a damaged heat exchanger causing high levels of CO in the furnace flue. A one-inch hole had been accidentally drilled through the cell core ABS plastic furnace vent (about 15 years ago). The heat exchanger corrosion and CO in the vent of this type and age of appliance may be common, but with an intact vent pipe, the CO would not usually enter the residence. Incorrect installation Residential Furnace Furnace - Natural gas
2-Feb-13 Vernon 1 0 0 1 Elevated levels of CO were reported at a residence. Kitchen exhaust fans in tight construction homes caused downdraft of B-vent, allowing flue products from the furnace to spill through the water heater draft hood. Combustion airflexible duct through the roof did not allow sufficient replacement air to make up for the exhaust fan draw. Combustion products unable to vent Residential Furnace Furnace - Natural gas
1-May-13 Princeton 1 1 0 0 A person died from carbon monoxide poisoning. The propane system and appliances were installed by an unqualified individual. The propane RV refrigerator was installed indoors not vented to outdoors, creating hazardous levels of carbon monoxide. Regulated work by unqualified person Residential Refrigerator, lanterns Refrigerator Lanterns Propane
26-May-13 Burnaby 2 2 0 0 Two people died from CO exposure in an industrial trailer used as living quarters. Use of a propane generator in an enclosed space. Unsafe use of equipment Converted industrial Generator Generator - Propane
6-Jun-13 West Vancouver 4 0 0 4 The utility responded to a gas leak call and detected elevated levels of CO at a residence. The utility technician discovered a leak at a flair fitting on the gas manifold. The B-vent piping was positively pressurized by a vent fan. The installation was not completed to the manufacturerÕs specifications, causing leakage. Incorrect installation Residential Boiler Boiler - Natural gas
21-Jul-13 Canoe 4 0 4 0 The utility responded to a CO alarm at a residence. The gas system in the home was incorrectly installed. The water heater was creating excessive amounts of CO. Incorrect installation Residential Furnace, water heater Water heater Furnace Natural gas
4-Oct-13 Cache Creek 1 1 0 0 A person was found deceased in a cargo trailer which was converted into a living space. Testing of the furnace suggest CO poisoning if the unit was occupied and furnace was used. Unsafe use of equipment Converted industrial Furnace, range Furnace Range Propane
11-Nov-13 Surrey 1 0 1 0 The utility responded to a CO alarm at a residence. A malfunctioning furnace created excess CO. The furnace had not received regular maintenance by a qualified individual. Lack of maintenance Residential Furnace Furnace - Natural gas
13-Dec-13 Surrey 0 0 0 0 The fire department and utility responded to a CO alarm at a residence. The furnace was found to have a defective heat exchanger allowing carbon monoxide to enter the home. Component failure Residential Furnace Furnace - Natural gas
15-Dec-13 Surrey 3 0 3 0 The utility responded to a CO call. Plugged heat exchanger on hot water boiler caused combustion products to spill into the residence. Lack of maintenance Residential Boiler, water heater Boiler, water heater - Natural gas
12-Jan-14 Surrey 1 0 0 1 The fire department responded to a CO alarm at a residence. The utility technician found that CO was entering the residence from a connection in the boilerÕs venting that had separated. A Weil McLain Gold series boiler was installed several years ago without a permit. The boiler is side-vented (Category III) with B-type vent. The venting material should be the approved pressure type vent (SafeT vent). The B-vent was pressed into the B-Vent 90 and held together with foil tape. The connection had separated, allowing the positive pressure vent gases to enter the boilerspace and migrate into the residence. Incorrect installation Residential Boiler Boiler - Natural gas
16-Mar-14 Enderby 1 0 1 0 The CO detector in the home was going off intermittently. The homeowner had been ignoring the alarm, thinking that the CO detector was malfunctioning. The homeowner awoke feeling dizzy and disoriented and called emergency services. A furnace spilled CO into a home. The gas contractor identified gas pressure issues caused by a second-stage regulator vent line that was plugged with insects. The gas pressure was floating between 7 and 22 inches water column due to the issue with the 50-year old regulator Vent obstructed; Combustion products unable to vent Residential Furnace Furnace - Natural gas
10-Sep-14 Saltspring Island 2 0 2 0 Tenants in a multi-family residence experienced dizziness and nausea after the installation and use of a new gas range. The natural gas range was installed by the homeowner and converted to propane by the tenant. Neither the homeowner nor tenant were not qualified to perform regulated work. There were no permits on record for the installation and/or conversion. Unqualified persons performing regulated work Residential Range, hot water tank, furnace Range - Propane
17-Sep-14 French Creek 1 0 1 0 The fire department responded to a CO alarm. A furnace created CO as a result of a cracked or plugged heat exchanger. The filter door was missing, allowing products of combustion to be circulated through the living space. Component failure Residential Furnace Furnace - Natural gas
16-Nov-14 Abbotsford 2 0 2 0 Two people were sent to hospital after experiencing symptoms of CO exposure. Emergency services (ambulance attendants, utility technicians) detected elevated CO readings in the residence. The top rain cap was found to be corroded to the point that the top lid of the rain cap collapsed on the top of the vent stack, blocking all combustion products from escaping. This condition caused the flue products to migrate back into the combustion chamber, leading to incomplete combustion and the generation of CO which then spilled into the residence. Corrosion Residential Furnace Furnace - Natural gas
22-Nov-14 Revelstoke 0 0 0 0 A boiler was not operating properly and was creating high levels of carbon monoxide. A wall-hung boiler was installed in a new home. The vent was not installed correctly. The vent had a joint near the boiler flue outlet that was not secured in any way. Incorrect installation Residential Boiler Boiler - Propane
26-Nov-14 North Vancouver 6 0 6 0 Six people were taken to hospital and treated for suspected carbon monoxide poisoning. Several individuals reported feeling nauseous with persistent headaches The venting system did not terminate to the outdoors. Combustion products were vented into the attic space. Insufficient combustion air Commercial Furnace Furnace - Natural gas
29-Nov-14 Winfield 3 0 3 0 Three people were sleeping when they were awoken by their CO alarm sounding. The occupants opened the windows to ventilate the house. The CO alarm sounded again around 4 hours after the initial alarm. The occupants were sent to hospital for treatment and observation. The seal around the fireplace glass was found to be leaking CO into the basement of the house. As well, the screws holding the fireplace glass in place were found to be loose. Equipment failure Residential Fireplace, furnace Fireplace - Natural gas
30-Nov-14 Surrey 15 0 15 0 Fifteen residents were sent to hospital for evaluation and treatment for carbon monoxide poisoning. The boiler venting was installed incorrectly permitting the products of combustion from the boiler to enter the home. In October 2014 a contractor installed a high efficiency condensing boiler in the basement of the home. The CPVC exhaust venting was installed inside an existing metal duct. The metal duct was open at both ends permitting products of combustion to enter the basement through the duct. Incorrect installation Residential Boiler Boiler - Natural gas
2-Dec-14 Surrey 3 0 0 3 A food processing facility was found to have a high concentration of CO within the facility. The utility technicians responded after employees reported feeling unwell. The water heater was not maintained and the noted spillage from the water heaterÕs draft hood was not addressed. Lack of maintenance Commercial Water heater, boiler, pan washer Water heater - Natural gas
2-Dec-14 Surrey 0 0 0 0 A homeowner was alerted by their carbon monoxide detector and contacted the utility. The technician found that the hot water boiler heat exchanger was plugged and was producing the CO that entered the home. Equipment failure Residential Boiler Boiler - Natural gas
4-Dec-14 Surrey 1 0 0 1 The utility responded to a report of a gas odour. The return air supply duct had been covered with a solid panel causing a negative condition in the water heater/furnace closet which allowed the products of combustion from the water heater to enter the air system into the dwelling unit through the air filter opening in the furnace ducting. The odor was from the products of combustion. There was approximately 25 ppm carbon monoxide in the dwelling unit where the return air had been sealed. The return air supply ducts from each of the units in a housing complex were originally supplied with a solid, sound insulated panel that was spaced away from the return air duct opening with screws and spacers. A furnace filter was installed in the opening between the panel and the return air duct opening. There was also a filter rack installed in the return air duct above the furnace. An employee had secured the panel in place without the spacers completely sealing the return air duct opening into the dwelling unit. The venting configuration did not permit the water heater to vent and there was an indication of continual spillage from the water heater draft hood. The products of combustion from the water heater were drawn into the furnace return air through the filter opening above the furnace. The combustion air for the furnace was originally provided via a 4Ó duct from the outside into the return air of the furnace. The outside opening was not visible as new soffits had been installed. There was also a duct into the crawlspace did not appear to be connected to an outdoor air source. Venting configuration did not allow combustion products to vent Residential Furnace, water heater Water heater - Natural gas
12-Dec-14 Surrey 2 0 0 2 The fire department and utility responded to a CO alarm at a residence. The hot water heating boiler had not been serviced in at least five years. The boiler burners and heat exchanger became dirty, producing high levels of carbon monoxide in the products of combustion. Some of the combustion products spilled from the boiler venting system into the home. Lack of maintenance Residential Boiler Boiler - Natural gas
20-Dec-14 Port Alberni 2 0 2 0 The fire department responded to a CO alarm at a residence. The homeowners also reported feeling ill recently and were advised by first responders to be evaluated at hospital. Following the incident, a utility technician observed CO readings in the supply ducting. It is suspected the cause to be a cracked heat exchanger due to CO readings in the plenum. Equipment failure Residential Furnace - Furnace Natural gas
13-Jan-15 Surrey 1 0 1 0 Emergency services responded to a CO alarm at a multi-family residence (townhouse units). The utility technician found low levels of CO but could not locate the source of the CO in the townhouse. In the adjacent unit, the technician measured high CO levels produced by the boiler. It was reported that the primary air adjustments on the boilerÕs burners were opened too much. This situation likely was likely created when the boiler was previously serviced. Inadequate service/ maintenance Residential Boiler Boiler - Natural gas
17-Jan-15 Chilliwack 5 0 5 0 After experiencing symptoms of vomiting, nausea and headaches, two residents were sent to hospital. The three other residents were also sent to hospital for testing. The furnace heat exchanger was found to have signs of corrosion. The furnace burners were dirty and appeared to have a yellow and lazy flame pattern. Insufficient maintenance Residential Furnace, dryer Furnace - Natural gas
24-Jan-15 Surrey 0 0 0 0 The utility responded to a CO alarm at a residence. The exhaust vent and combustion air supply were terminated using a concentric vent termination. The termination was installed less than 12" above the finished grade which permitted combustion products to be reintroduced into the water heater burner. This increased the carbon monoxide in the exhaust gases. Incorrect installation Residential Water heater Water heater - Natural gas
17-Mar-15 Charlie Lake 3 0 3 0 Residents contacted the utility after experiencing headaches. The utility technician measured 190 ppm of carbon monoxide. (Not described) Unable to determine cause Residential Furnace - Furnace Natural gas
5-May-15 Coquitlam 1 0 1 0 A resident went to hospital for suspected CO poisoning. The fire department measured 70 ppm CO in the water heater room and 10ppm in the rest of the residence. Exhaust from a gas appliance spilled into a dwelling unit. When the water heater was installed, the combustion air vented to the exterior, however the exhaust was venting into the dwelling unit. The start-up and testing procedures were not followed. Start-up testing procedures are intended to ensure the unit is operating in a safe condition). Incorrect installation Residential Water heater Water heater - Natural gas
15-Nov-15 Langford 1 0 1 0 Emergency services responded to a CO alarm. Air tests measured levels of 25-50ppm carbon monoxide in free air in the space and over 100ppm near the two fireplaces Inspection of the fireplace showed a poorly aligned seal on the fireplace door, allowing combustion products to escape into the occupied space. Equipment failure - component failure Residential Fireplace Fireplace - Natural gas
12-Dec-15 Surrey 0 0 0 0 A gas odour was reported. The vent connector from the boiler and the water heater had been connected to the combustion air supply duct instead of the B vent. The vent connector had signs of sooting and the combustion air duct was sooted, as well. Incorrect installation Residential Boiler, water heater Boiler, water heater - Natural gas
13-Dec-15 Surrey 2 0 1 1 The utility responded to a CO alarm at a residence. Suspected plugged heat exchanger Equipment - component failure Residential Boiler, water heater - Boiler, water heater Natural gas
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