Twenty one people died in carbon monoxide (CO) related incidents last year according to data from the gas safety registration body.
In its second report on the subject, Corgi said today that between April 2007 and March 2008, there were 63 CO incidents, resulting in 21 fatalities and 125 injuries.
Between January 2006 and April 2007, there were 102 carbon monoxide incidents claiming 50 lives and causing 218, often long-term, injuries.
Corgi said the 07/08 figures could be much higher since there was an absence of any official, centralised incident reporting system which meant many cases were going undiagnosed.
The report said: 'One of the key issues that this report highlights is the lack of a robust reporting system.
'This is required so that the industry can determine the true extent of the number of carbon monoxide incidents, especially the number of casualties.
'Until this issue has been resolved it is very unlikely that we will ever be able to tell the true number of carbon monoxide poisoning incidents that occur from not only gas appliances, but also oil and solid fuels.'
London, Yorkshire, the Midlands and Wales are the worst affected regions in the UK, reporting the most incidents per head of population. The elderly, those living in private rented accommodation and those living in non-English speaking communities have all been identified as vulnerable groups.
Carbon monoxide poisoning can be cause by many factors such as blocked flues and chimneys, installation or appliance faults, owner error and even weather conditions, Corgi said.
Counter measures recommended to reduce the risk of carbon monoxide poisoning include using a fully qualified installer to annually service appliances.