Two long-awaited studies of how cell phone radiation affects the health of mice and rats, released yesterday, are giving scientists plenty to think about - but the findings won't resolve the decades-old uncertainty surrounding the issue.
For humans who text, watch videos and sometimes even talk on cell phones, the concern has been whether radiofrequency radiation might lead to brain tumors.
In male rats, the studies linked tumours in the heart to high exposure to radiation from the phones. The toxicology programme is headquartered at the National Institute of Environmental Health Sciences. The rats received radiation over their entire bodies for nine hours a day for two years.
The 10-year, $25 million study by the National Toxicology Program found subjecting the bro-dents to high levels of radiofrequency radiation - the radio waves used by cell phones - resulted in tumors growing around male rats' hearts, although female rats and mice of either gender didn't suffer the same consequences. Sex- and species-dependent increases were also observed for lymphoma, as well as cancers of the prostate, skin, lung, liver and brain, but these findings were weaker by comparison and possibly due to causes other than radiation.
Unlike ionizing radiation such as that from gamma rays, radon and X-rays, which can break chemical bonds in the body and are known to cause cancer, radiofrequency devices such as cellphones and microwaves emit radiofrequency energy, a form of non-ionizing radiation.
Early reactions to the findings suggest they will not dramatically reshape the debate over cell phone safety.
The new findings are "incredibly important", says David Carpenter, a public health physician at the University of Albany, New York, who has long warned of cell phone dangers.
In a statement to NBC News, the wireless industry said there's no evidence backing the study saying, "since the introduction of cell phones in the mid-1980s, the rate of brain tumors in the united states has remained stable". Unfortunately, these reports only increase the cell phone radiation enigma.
"Based on this current information, we believe the current safety limits for cell phones are acceptable for protecting the public health", director Jeffrey Shuren said in a statement. However, some studies didn't clearly show a connection between cell phone radiation and cancer.
"We understand that the NTP draft reports for its mice and rat studies will be put out for comment and peer review so that their significance can be assessed", the group said.
The FDA noted that even then, the links to cancer were "mostly equivocal, or ambiguous".
NTP, a part of the National Institutes of Health, will hold an external expert review of its findings on March 26-28.
The FDA has proposed cell phone radiation for carcinogenicity and toxicology testing since 1999.