Cell phone masts are harmless - say researchers

Mobile phone masts (towers) do not cause harmful short-term health effects, according to a study of people who say they experience symptoms when they are close to them. The study runs counter to the notion that low-level electromagnetic fields from cell phones or their base stations carry risks.

The British researchers looked at 2G and 3G phone masts in a laboratory setting where both the participants and researchers did not know whether the equipment was turned on.

The set-up was designed to mimic (imitate) the output from a phone mast at 20 to 30 metres from the subject.

"It looks like there was pretty good evidence that people couldn't detect the signals", said Elaine Fox at Essex University who led the study. It was published in the journal Environmental Health Perspectives.

Of the 159 people who participated in the experiment, 44 said they were sensitive to electronic equipment. At first they were told when the electric field was turned on while being tested. Under these conditions, the electro-sensitive participants reported symptoms such as headaches and nausea (sick feeling).

In three further tests, researchers subjected them to 2G radiation, 3G radiation or no radiation under "double blind" conditions, meaning no one involved knew whether the equipment was switched on.

Under these conditions, two of the electro-sensitive group and five of the control group correctly identified whether the electricity was on every time - no better than you would expect by chance alone.

The team measured heart rate, blood volume pulse and sweatiness of the skin. All of these should go up when the participants experience unpleasant symptoms or anxiety.

The electro-sensitive individuals had generally higher scores than the control group for all three, but they did not change when the 2G or 3G radiation was switched on. Anti-phone mast campaigners said the results were skewed (twisted) since 12 volunteers who claimed to be sensitive to electronic equipment had dropped out.

"Even a child can see that by eliminating 12 of the original 56 electro-sensitive volunteers ... the study integrity has been completely breached(affected)," the group Mast Sanity said. It argues these people were presumably the ones most sensitive to the radiation.

Professor Fox counters that her team was still able to test 44 people and of the dropouts, none was able to identify correctly when the radiation was on or off in the first double blind test.

The reduced numbers do mean the statistical power of the experiment was compromised, though. Prof. Fox estimates there is a 30 per cent chance that the experiment missed a real effect because of the smaller numbers. Some anti-mast campaigners are impressed. "The Essex team have carried out one of the best-designed and executed studies to date", the group Powerwatch said.

Prof. Fox said scientists should now concentrate on finding the real cause of the symptoms. "If people are convinced they are suffering because of mobile phone masts they don't investigate other causes".

The Guardian