During a meeting break, I step outside to use my mobile phone. As I finish the call, an older gentleman jokes that in his day, they all smoked during breaks and risked lung cancer; now we all use mobiles and risk brain cancer. But with more than a billion mobile phones in use, any considerable health risks would probably have appeared by now. For instance, the recent Interphone study seems inconclusive, flawed with various biases. Perhaps the $30 million cost of the study could have been better spent on distributing free sunscreen, if the goal is cancer prevention.In some discussions about femtocells, I’ve heard concerns about a new source of radiation in your home. But actually, since a nearby femtocell is easier to reach than a distant cell tower, the phone can reduce its transmit power and irradiate your head less, if ever so slightly. As usual, I’d expect most users would put aside such worries in favor of convenience and cost advantages.A much more substantial danger of mobile devices is letting them distract you while driving. California recently passed a “hands-free” law requiring the use of a headset or speaker, rather than holding the phone to your ear. Given California car culture, an outright ban on mobile phone use while driving would have been difficult, but experience strongly suggests it’s the conversation that’s distracting, more than holding the phone. (In fact, the added fuss of activating a Bluetooth speaker has probably raised the risk for many people.) I’m not sure the hands-free law makes us much safer, but it will sell more accessories for the mobile phone industry, so score a point for their lobbyists.Even more dangerous than talking is texting while driving. A recent British study suggests that texting while driving is substantially more dangerous than driving drunk or stoned. This finding makes intuitive sense. Taking your eyes off the road, your hands off the wheel, and your mind off the situation seems like a recipe for disaster. Such a disaster recently befell the passengers of a Los Angeles commuter train, when their engineer plowed into a freight train without even braking, apparently distracted as he sent his last text message just 22 seconds before impact.The Mobile Internet is very exciting, but it can also be very distracting. If you’re doing something dangerous, like driving, put your mobile device away. And if you see drivers wearing this sort of video glasses, give them a wide berth indeed!