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 yesterday 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 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 at the University of Texas. 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.

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 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.