The National Toxicology Programme study was started in the Clinton administration when the government was still interested in science and less interested in what the Bible or big corporates had to say. It cost $30 million and involved some 3,000 rodents

It found positive but relatively modest evidence that radio waves from some types of mobile phones could raise the risk that male rats develop brain cancer. But he cautioned that the exposure levels and durations were far more significant than what people typically encounter, and thus cannot "be compared directly to the exposure that humans experience."

Moreover, the rat study examined the effects of a radio frequency associated with an early generation of mobile technology, one that fell out of routine use years ago. Any concerns arising from the study thus would seem to apply mainly to early adopters who used those bygone devices, not to users of current models.

The lowest level of radiation in the federal study was equal to the maximum exposure that federal regulations allow for cellphone users. That level of exposure rarely occurs in typical mobile phone use, the toxicology agency said. The highest level was four times higher than the permitted maximum.

The rodents in the studies were exposed to radiation nine hours a day for two years -- far longer even than heavy users of mobiles. For the rats, the exposures started before birth and continued until they were about two years old.

Some 2- 3 per cent of the male rats exposed to the radiation developed malignant gliomas, a deadly brain cancer, compared to none in a control group that received no radiation. Many epidemiologists see no overall rise in the incidence of gliomas in the human population.

"The study also found that about 5-7 per cent of the male rats exposed to the highest level of radiation developed certain heart tumours, called schwannomas, compared to none in the control group," the NYT reports.

The rats were exposed to radiation at a frequency of 900 megahertz, the frequency used in the second generation of mobile phones that prevailed in the 90s when the study was first conceived. For comparison, fourth generation (4G) and fifth generation (5G) phones employ much higher frequencies, which are "far less successful at penetrating the bodies of humans and rats," the New York Times reports.

To be fair to the study though the New York Times is an unofficial press office for one of the largest suppliers of mobile phones – Apple.