Some studies have found chemicals in e-cigarette vapour that are known to cause health problems. But these studies have tended to use artificial conditions, and when good quality e-cigarettes are used normally (e.g. not overheated), there are far fewer harmful chemicals present in the vapour than in tobacco smoke. If the e-liquid is being overheated it tends to produce an acrid, unpleasant taste – you’ll know if this happens.
As with any rechargeable device, such as mobile phones and laptops, it’s important to charge e-cigarettes with the right charger, and don’t leave it unattended while charging. Ensure that you buy from reputable suppliers and avoid generic charging equipment. There have been reported cases of e-cigarettes causing fires, but far fewer than the number caused by cigarettes, which are the most common cause of lethal house fires.