As outside temperatures continue to drop, wildlife are seeking shelter from the cold winter weather. Among their favourite den sites are attics and chimneys. 

Wildlife living in attics are inclined to chew on electrical wires, posing the possibility of an attic fire. An even greater danger exists when the squirrels’ nesting material blocks the exhaust of a gas chimney causing odourless carbon monoxide fumes to back up inside the house. 

Recently, a technician of our company was called to two separate homes to investigate squirrels nesting in gas furnace chimneys. What he discovered could have developed into a very dangerous, if not lethal situation. In one case the squirrel had squeezed past an ill-fitted top plate and built a nest between the gas liner and the brick of the chimney. Gas furnace chimney liners, when improperly installed, can allow animals easy access to move inside. 

Once inside, squirrels will eventually chew open the flexible liner and then begin to fill it with nesting material. Once the liner is compromised the safe exhaust of carbon monoxide gas to the outside is no longer possible. Unable to find its way out of the top of the chimney, carbon monoxide gas begins to penetrate the house, causing the occupants to unknowingly slip into unconsciousness. If they are not rescued in time they will unfortunately die. This exact situation occurred in Toronto years ago. Over the course of two days it left two people dead and two more clinging to life. 

The danger of carbon monoxide poisoning is always looming, therefore preventative steps should be taken to eliminate the risk. 

• Have all gas chimneys inspected, paying close attention to the top plates to en- sure they are firmly affixed to prevent animals from climbing in 
• Have all gas appliances inspected and cleaned to ensure safe functioning 
• Install a carbon monoxide detector on every level of the home 
• Strictly adhere to the manufacturer’s instructions as to replacing the detec- tors and batteries 
• If there is suspicion of an animal living in a chimney, immediately call the gas company to investigate the possibility of a carbon monoxide leak. Furthermore, a reputable wildlife removal company should be hired to remove the animals and the nesting material 

By Brad Gates, B.Sc.

Brad Gates is the owner and president of AAA Gates Wildlife Control. He has over 35 years experience in the humane wildlife removal and prevention industry.