LONDON -- A respected international panel of scientists says cellphones are possible cancer-causing agents, putting them in the same category as the pesticide DDT, gasoline engine exhaust and coffee.
The classification was issued Tuesday in Lyon, France, by the International Agency for Research on Cancer after a review of dozens of published studies. The agency is an arm of the World Health Organization and its assessment now goes to WHO and national health agencies for possible guidance on cellphone use.
Classifying agents as "possibly carcinogenic" doesn't mean they automatically cause cancer, and some experts said the ruling shouldn't change people's cellphone habits.
"Anything is a possible carcinogen," said Donald Berry, a professor of biostatistics at the M.D. Anderson Cancer Center in Houston. He was not involved in the WHO cancer group's assessment. "This is not something I worry about and it will not in any way change how I use my cellphone," he said -- speaking from his cellphone.
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The same cancer research agency lists alcoholic drinks as a known carcinogen and night shift work as a probable carcinogen. Anyone's risk for cancer depends on many factors, from genetic makeup to the amount and length of time of an exposure.
After a weeklong meeting on the type of electromagnetic radiation found in cellphones, microwaves and radar, the expert panel said there was limited evidence that cellphone use was linked to two types of brain tumors and inadequate evidence to draw conclusions for other cancers.
"We found some threads of evidence telling us how cancers might occur, but there were acknowledged gaps and uncertainties," said Jonathan Samet of the University of Southern California, the panel's chairman.
"The WHO's verdict means there is some evidence linking mobile phones to cancer, but it is too weak to draw strong conclusions from," said Ed Yong, head of health information at Cancer Research U.K. "If such a link exists, it is unlikely to be a large one."
Last year, results of a large study found no clear link between cellphones and cancer.
The study was controversial because it began with people who already had cancer and asked them to recall how often they used their cellphones more than a decade ago.
In about 30 other studies done in Europe, New Zealand and the U.S., patients with brain tumors have not reported using their cellphones more often than unaffected people.
The cellphone industry trade group, CTIA-The Wireless Association, said two U.S. agencies have found no evidence that cellphones are linked to cancer -- the Food and Drug Administration and the Federal Communications Commission.