Posted By Barry Mageean I understand that Carbon Monoxide is odourless. What I would like is some clarification on whether in a fire situation the Carbon Monoxide will always be accompanied by visible smoke? Is it possible for Carbon Monoxide to travel independently or even in front of spreading smoke? Many thanks.

Posted By Bob Pedley Barry, In a free burning fire situation, my understanding is that CO is produced as part of a chain reaction during the combustion process. CO is reactive and will burn to produce the stable carbon dioxide as an end product. The white fumes present in a simple fire burning say wood or paper will be water vapour. In other types of fire this could be more complex toxic fumes. In simple terms, the visible smoke seen in a fire may contain CO if there isn't enough oxygen or heat around to complete the chain reaction but is more likely to contain water vapour as the main constiuent. My advice would be don't try to get scientific about this, it is a very complex area. Regards Bob