With millions of new devices - cellphones, cordless phones and Wi-Fi networks - that emit electromagnetic fields becoming indispensable in homes and workplaces, should we be worried about the hidden health effects?
Yes, according to the BioInitiative Working Group, a collection of researchers from around the world who have written a report based on thousands of studies that look for links between EMF emissions and diseases like leukaemia and brain cancer.
No, according to a committee that advises the Government about the issue and which last week discussed the working group report. Committee chairman Jim Turnbull, group manager at the National Radiation Laboratory, part of the Ministry of Health, says the lab's radiation and radio frequency (RF) exposure guidelines follow the lead of the World Health Organisation (WHO) and won't be changing.
In 1996, the WHO began the EMF Project to keep an eye on evidence of health problems relating to radiation in the 0-300GHz range. The project's leader, Dr Emilie van Deventer, says the working group's report has been noted but won't result in any alteration of the WHO's fact sheets on EMF exposure.
Of cordless phones and Wi-Fi networks, the WHO says: "Considering the very low exposure levels and research results collected to date, there is no convincing scientific evidence that the weak RF signals from base stations and wireless networks cause adverse health effects." Dr David Carpenter, of the University of Albany in New York state, a co-editor of the report, begs to differ.
Carpenter says the report's contributors show strong enough links between heavy, long-term cellphone use and brain tumours, for instance, for a "business as usual" response from decision-makers to be unacceptable.
He says there tends to be a lag of many years between exposure to radiation and tumour growth but the number of cases already apparent suggest a much bigger problem to come.
"One would expect this to be only the tip of the iceberg because of the long latency of those diseases," Carpenter says.
Added to that is the increasing use of cellphones, especially by young people.
If that sounds alarming, it's not forceful enough for American Arthur Firstenberg, author of the 1996 book Microwaving Our Planet: The Environmental Impact of the Wireless Revolution.
Firstenberg has been preoccupied by the issue since the 1980s when, as a medical student, he became convinced that radiation from operating theatre equipment was making him ill. He says he's not a voice in the wilderness.
"If you go on the internet you'll find a lot of people are screaming about this." British website mast-victims.org is one place they congregate.
Firstenberg says the real issue is not brain tumours but a smorgasbord of symptoms, collectively called microwave syndrome, including asthma, diabetes, heart disease, cataracts, nausea, dizziness and insomnia.
Such is his susceptibility that he can't live in built-up areas and is reduced to sleeping in his car in a remote part of South Dakota. "I'm a refugee," he says.
The BioInitiative Working Group says its analysis shows health effects at exposure that is "hundreds or even thousands" of times below limits considered safe. Yet its report has had little mainstream media coverage since its release at the end of last month.
Firstenberg likens the issue to the global warming debate, in which believers outnumber sceptics, but the media presents it as though there is equal weight of opinion on either side. In fact, he says studies showing health effects of RF exposure outnumber those that don't.
Carpenter has a slightly different explanation, saying vested interests - the companies in the process of rolling out wireless networks in American cities - are happy for the issue to stay beneath the radar.
"None of the discussion in the decision about whether a city would have wireless ... has focused on the possible health effects." Even more damning, he says many studies are tainted by funding from industry.
Turnbull says that regardless of whether one believes EMF and RF exposure are making people ill, science hasn't - and can't - prove it.
Both sides accept that radiation heats tissue, which is what makes microwave ovens so useful.
But those who are convinced that people are being harmed believe the radiation is interfering with the body's own electromagnetic waves and damaging DNA.
New Zealand scientist Dr Neil Cherry, who died an untimely death from motor neurone disease in 2003, was a leading proponent of that theory.
Curiously, while the WHO has one fact sheet advising that wireless phones and networks are safe, it has another acknowledging that large numbers of people suffer from "electromagnetic hypersensitivity" or EHS.
EHS' non-specific set of symptoms include rashes, skin tingling and burning sensations, fatigue, concentration difficulties, dizziness, nausea, heart palpitation and stomach upsets.
Without quite stating it, the document conveys the impression that EHS is a psychosomatic condition. The speculation is that it came into existence as a sop to former WHO director-general Gro Harlem Brundtland, who had EHS.
On the issue of more serious and specific health effects, Van Deventer says the WHO is awaiting the release of a 13-country study - including New Zealand - of the relationship between cancers in the head and neck and cellphone use. Industry bodies provided some of the study's funding.
On top of that, "a formal health risk assessment of RF fields will be undertaken by WHO over the next couple of years", Van Deventer says, and the results will "hopefully" be published in 2010.
By then, if cellphones continue to fly off the shelves at the present rate, another three billion will have been sold worldwide. Germany, and the European Environment Agency, however, aren't waiting around for the results.
Britain's Independent newspaper reports that the German Environment Ministry this month said people should avoid using Wi-Fi networks where possible, while its radiation-protection body urges the use of landlines instead of cellphones.
The EEA, meanwhile, wants European authorities to recommend actions to reduce EMF exposure, warning of a potential health crisis similar to that from smoking.
* Anthony Doesburg is an Auckland-based technology journalist
Are radiation sources such as cellphones, cordless phones and Wi-Fi networks a proven danger to health?
* Yes, says the BioInitiative Working Group. It claims there can be health damage even if exposure is a fraction of accepted "safe" levels.
* No, says the World Health Organisation and local authorities, who see no need to change current guidelines.