According to GAS SAFE, the gas registration body for the UK, more than a million households are put at risk by illegal gas fitters each year.By law, all gas engineers must be on the Gas Safe Register, whose main focus is on improving and maintaining gas safety to the highest standards. Yet in a recent study, it found that ‘illegal gas fitters installed over 186,000 gas cookers, 147,000 boilers, 75,000 gas fires, 32,000 gas meters and 645,000 gas pipe work over one year’.The importance of correct and safe installation and maintenance of gas appliances can’t be stressed enough as the consequences of unsafe appliances can be deadly. Carbon Monoxide, often called the invisible killer, has no smell or taste, and the most common causes of accidental exposure to it are appliances such as cookers, heaters and central heating boilers which have been incorrectly installed and/or poorly maintained.