The Economist reports (subscription required):
ALTHOUGH the myth that mobile phones cause cancer has been laid to rest, an implacable minority remains convinced of the connection. Their fears have been aggravated of late by bureaucratic bickering at the World Health Organisation (WHO). Let it be said, once and for all, that no matter how powerful a radio transmitter—whether an over-the-horizon radar station or a microwave tower—radio waves simply cannot produce ionising radiation. The only possible effect they can have on human tissue is to raise its temperature slightly.
In the real world, the only sources of ionising radiation are gamma rays, X-rays and extreme ultra-violet waves, at the far (ie, high-frequency) end of the electromagnetic spectrum—along with fission fragments and other particles from within an atom, plus cosmic rays from outer space. These are the sole sources energetic enough to knock electrons out of atoms—breaking chemical bonds and producing dangerous free radicals in the process. It is highly reactive free radicals that can damage a person’s DNA and cause mutation, radiation sickness, cancer and even death.
By contrast, at their much lower frequencies, radio waves do not pack anywhere near enough energy to produce free radicals. The “quanta” of energy (ie, photons) carried by radio waves in, say, the UHF band used by television, Wi-Fi, Bluetooth, cordless phones, mobile phones, microwave ovens, garage remotes and many other household devices have energy levels of a few millionths of an electron-volt. That is less than a millionth of the energy needed to cause ionisation.
All of which leaves doctors more than a little puzzled as to why the WHO should recently have reversed itself on the question of mobile phones. In May the organisation’s International Agency for Research on Cancer (IARC) voted to classify radio-frequency electromagnetic fields (ie, radio waves) as “a possible carcinogenic to humans” based on a perceived risk of glioma, a malignant type of brain cancer. . .
The Group 2B classification the IARC has now adopted for mobile phones designates them as “possible”, rather than “probable” (Group 2A) or “proven” (Group 1) carcinogens. This rates the health hazard posed by mobile phones as similar to the chance of getting cancer from coffee, petrol fumes and false teeth.
The WHO’s unfortunate waffling gives alarmists somewhere to hang their hat. As a result, we get misleading stories such as one in the January 2012 Consumer Reports which conveyed the impression of a risk by failing to observe that the “possible” designation was the lowest risk level, the same as coffee, and by allocating much more space to equivocal studies that failed to disprove a risk than to definitive studies that did disprove a risk.