Answer to Question #6647 Submitted to "Ask the Experts"

"Safety" is an elusive quality, which refers to a social question (what kinds of risks are acceptable to a person) and not just scientific data. No set of studies can be done to prove that something is "safe." There is also the impossibility of proving the negative—the absence of health risks. For those reasons, health agencies almost never certify anything as "safe" but rather try to describe the state of present knowledge and summarize presently available knowledge about health risks.

Mobile phones operate at generally similar frequencies as microwave ovens and some TV channels (in the United States the mobile phone industry was created when the U.S. government reallocated a TV channel for communications use). However, the exposure to a user from a mobile handset is certainly higher than from a microwave oven. Such exposures are almost certainly below international safety limits. Expert reviews in the United Kingdom, the Netherlands, and other countries have concluded that international exposure guidelines provide adequate protection against all known hazards of radiofrequency energy. Consequently—and I agree—there is no scientific basis to anticipate health risks from mobile phones. I also agree that it is prudent to carefully investigate possible health risks from any new technology.

The "safety" of radiofrequency energy is a very complicated issue. I entered the field in 1971 as a recent PhD and newly commissioned naval officer. I was assigned to study biological effects of radiofrequency energy, in part because of occupational safety concerns of the Navy but also because of public fears about the safety of military radar and communications systems. At that time, there were already more than a thousand papers on biological effects of microwave energy, and people had been arguing about biological effects of radiofrequency energy (a broad term which includes microwaves) since at least the 1930s.

Starting in the 1950s, the U.S. government began to commission studies to investigate possible hazards of microwave energy and to commission expert groups to evaluate the safety of radiofrequency energy to address public concerns. The only things that were clear were that (1) the only established hazards of radiofrequency energy require high-exposure levels and are associated with too much heating and (2) there is a lot of uncertainty in the literature and more research is needed.

The same could be said now, 36 years later. There are now several thousand papers in the field, but the same arguments are being debated as in 1971, although the technologies themselves have changed. As before, the scientific literature is large and inconsistent in many places, and people who are inclined to worry can choose bits and pieces of evidence to justify their fears, even as health agencies conduct comprehensive reviews of the literature and fail to find clear evidence for a hazard. These controversies will probably continue for quite a while longer.

Here are some recent reports from expert groups on the issue:

1. Documents of the National Radiological Protection Board (UK): Volume 15, No. 3, Review of the Scientific Evidence for Limiting Exposure to Electromagnetic Fields (0–300 Ghz) Available at: http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1194947383619.
   
   
2. Health Council of the Netherlands: Mobile Telephones: an Evaluation of Health Effects. The Hague: Health Council of the Netherlands, 2002. Available at: http://www.gr.nl/pdf.php?ID=377. (The Health Council of the Netherlands has published several additional reviews on the issue of possible health effects of electromagnetic fields, which are available on its Web site.)
   
   
   

Kenneth R. Foster, PhD, PE