On 11 October Samsung stopped all production of its Galaxy Note 7 smartphone after several handsets exploded or caught fire.
Production of the Note 7 had been suspended one month previously after some of the models sold under its initial release experienced similar problems, but the phone had subsequently been relaunched.
Perhaps belatedly, many airlines have now banned the Note 7. But where does your smartphone figure in the list of potential threats to your life?
Samsung states that there were problems with the batteries of 35 out of 2.5 million Galaxy Note 7 handsets sold, a rate of 1.4 per 100,000. This means that, even if you already own a Note 7 you are statistically far more likely to be murdered than to experience battery failure: in Europe there are 3 homicides per 100,000 of population.
Exploding phones represent a tiny proportion of total handsets. There are currently an estimated 6.9 billion mobile handsets globally in use. However, only one in ten million lithium-ion battery cells are likely to develop a fault: that is just 690 of the total phones worldwide. By any measure, the likelihood of your mobile battery failing, let alone blowing up, is vanishingly small.
So why do lithium ion batteries fail? Occasionally there are manufacturing faults, or damage to the battery caused by, for example, a smashed handset. They can also fail because of the tension between safety and consumer demands for reduced charging times: the faster the battery charges, the higher the risk that lithium plates will form around the battery’s anode and create a short circuit. This is what is believed to have happened with Samsung.
Perhaps more dangerous than the technology itself is its human interface. Each year the London Fire Brigade repeats its warnings about fires started by people using poor quality chargers.
Third-party battery replacements, mobile phones in bathtubs, and even microwaved handsets have all also caused fires, but these incidents can hardly be blamed on the manufacturers. Nor can all the accidents and deaths caused by people using their smartphones when they should have been concentrating on the road.
Distractions caused by a phone or other device accounted for up to 1 in 5 car accidents in the US in 2013.
But are there other ways your phone could kill you? Some believe that you are more likely to suffer a lingering death than to go up in a puff of smoke. Ever since they first appeared, mobile phones have been the focus of concerns about cancers caused by the radiation they emit, with campaigners decrying a cover-up.
One of the difficulties with any assessment of the risk of cancer posed by mobile phones is the lack of necessary long-term data. The COSMOS cohort study is designed to supply this.
Unlike studies which have preceded it, COSMOS is following a vast group of 290,000 apparently healthy subjects. These subjects were given questionnaires about their mobile usage to complete in 2010 and 2015, and will be again in 2020. Their answers will be cross-checked against data from providers.
It is still too early to tell whether a link will be shown between mobile phone usage and the diseases being looked at, namely cancer, cardiological and neurological disease, persistent headaches, sleep disorder, and tinnitus.
However, Roel Vermeulen, one of the researchers working on the project, says that “if there was a very high risk of developing one of these diseases from mobile phones, we would expect to have already seen sharp upwards trends in the levels of that disease in the population. We have not seen these, so any risk associated is likely to be at the lower end. However, given the ubiquitous use of mobile phones, even a small risk could have public health importance.”
In short, you can probably kill yourself by using your phone unwisely, but your phone is unlikely to kill you.