This is the VOA Special English Technology Report.

The World Health Organization has added to the debate over the risk of brain cancer from mobile phone use. Last week the WHO's International Agency for Research on Cancer listed the signals from wireless devices as "possibly carcinogenic." This finding puts cell phones in the same risk group as the pesticide DDT -- but also in the same group as coffee.

A group of 31 scientists from 14 countries made the finding. The announcement came at the end of a meeting at the agency's headquarters in Lyon, France.

The concern is that extended contact with radiofrequency electromagnetic fields may increase a user's risk for glioma. Glioma is the most common form of brain cancer.

The scientists spent a week examining existing research. Dr. Jonathan Samet from the University of Southern California led the group.

JONATHAN SAMAT: "We also carefully consider the sources of exposure of populations to radiofrequency electromagnetic fields, the nature of these fields as they come from various devices, including wireless phones, and we look carefully at the physical phenomenon by which exposure to such fields may perturb biological systems and lead to cancers."

He says the finding that there could be some risk means scientists need to keep a close watch for a link between cell phones and cancer.

The statement noted that the number of mobile phone users is large and growing, especially among young adults and children. Mobile phone subscriptions are estimated at five billion worldwide.

The scientists called for more research into long-term, heavy use of mobile phones. They also suggested taking measures to reduce exposure to the signals, like hands-free devices or texting.

Camilla Rees from an American group called Electromagnetic Health praised the report but says wider research is needed.

CAMILLA REES: "We've only had this technology around for about 15 years, and most carcinogens will take about several decades, 30-40 years to develop a cancer. So based on some early indications, scientists are projecting that we're actually going to be seeing a tsunami of brain cancer unless we do something to educate people to lower their exposure to this kind of risk."

CTIA, the International Association for the Wireless Telecommunications Industry, dismissed the report. The group pointed out that no new research had been done. And it noted that the cancer research agency has given the same finding to things like coffee and pickled vegetables.

And that's the VOA Special English Technology Report, written by June Simms. You can find a link to the statement from the World Health Organization at voaspecialenglish.com. And while you're there, tell us your thoughts about this whole issue of mobile phone safety. I'm Steve Ember.

carcinogenic: likely to cause cancer 致癌的

glioma: a malignant tumor of the glial tissue of the nervous system 神經膠質瘤

Related stories:

After brain study, new questions about mobile phones

聽別人打電話為什么心煩？

手機會致癌嗎？

Study shows no link between cell phones and rare tumor

（來源：VOA 編輯：崔旭燕）