For decades, health experts have struggled to determine whether or not mobile phones can cause cancer. Now a study found positive but relatively modest evidence that radio waves from some types of cellphones could raise the risk that male rats develop brain cancer.
The study is carried out by the National Toxicology Programme released the final results of the world’s largest and most costly experiment to look into the question. The study originated in the Clinton administration, cost $30 million and involved some 3,000 rodents.
The rat study examined the effects of a radio frequency associated with an early generation of cellphone technology, one that fell out of routine use years ago. The rodents in the studies were exposed to radiation nine hours a day for two years — far longer even than heavy users of cell phones. For the rats, the exposures started before birth and continued until they were about 2 years old.
The rats were exposed to radiation at a frequency of 900 megahertz — typical of the second generation of cell phones that prevailed in the 1990s when the study was first conceived.
Current cell phones employ much higher frequencies, and these radio waves are far less successful at penetrating the bodies of humans and rats, scientists say.