Wednesday, June 1 2011, 10:07 PM CDT  MADISON (WMSN) -- The World Health Organization says you have as much chance of developing cancer from cell phone use, as from exposure to chloroform and the pesticide DDT.

A group of 31 scientists from two dozen countries reclassified cell phone radiation today as "possibly carcinogenic."

The scientists reviewed dozens of published studies and found there was some evidence of an increase in two types of brain cancer in mobile phone users.

The chairman of the committee tells Fox 47 News more research is needed.

"I think there's a warning here for public health to make sure we're tracking brain cancer rates very carefully and trying to continute to measure if there's any increased risk for cell phones," said Dr. Jonathan Samet, Chairman of the World Health Organization Working Group.

Dr. Samet says cancerous tumors can take decades to develop and the studies conducted so far haven't tracked people for more than about 10 years.

Last year, researchers estimated more than 3/4 of the world's population uses cell phones.

Studies link cell phone use to brain cancer