Most people don't know what carbon monoxide is, so you're not alone if you're unsure.
Carbon monoxide (CO) is a colourless, odourless, tasteless, poisonous gas that is released when any fossil fuel, such as coal, oil, wood, petrol, barbeque charcoal and gas, doesn't burn properly.

Breathing it in can make you unwell, and it can kill. Even low levels of exposure, over a long period, can cause serious health issues.

Download our free carbon monoxide pocket guide, produced in association with Wales and West Utilities, and share with family members, colleagues and groups.