Also known as the 'silent killer', carbon monoxide kills approximately 50 people each year in Britain. 
Symptoms include
headaches, nausea, vertigo and altering states of consciousness.
Spotting the signs
If a gas appliance is working correctly, it should have a bright blue flame which indicates it is healthy. If it is yellowy orange, there is evidence of possible carbon monoxide.
Other things to look out for
Brownish, yellow stains around the appliance, pilot lights which blow out frequently and heavy condensation in the room where the appliance is sited.
Make sure you have your gas appliances services regularly. If you have any concerns contact us on 0800 1380 380.