's worth being aware of this classification -- just as you should be mindful of your intake of coffee , another group 2B carcinogen . But this announcement is not a reason to panic . Would labels help ? San Francisco has been wrestling with whether to require cell phones to be labeled for their RF emissions . Last year , the city tried to mandate cell phone radiation labeling in stores , originally to take effect February 2011 . But according to the San Francisco Chronicle , `` implementation was delayed until May 1 , then June 15 . There now is no proposed start date . '' The city backtracked on this partly out of concern over a lawsuit filed by the Cellular Telecommunications and Internet Association -- but also because officials did n't know how to ensure the accuracy of the labels . Scientists are n't sure what 's the most realistic , intuitive way to communicate cell phone RF emissions to consumers . Specific absorption rate , a measure of the rate of RF energy that your body absorbs from the phone , is the most commonly cited benchmark . For a phone to be certified
-LRB- CNN -RRB- -- Following the World Health Organization 's announcement that radio frequency emissions from cell phones may increase the risk of some kinds of brain cancer , what do you need to know about the radiation coming from your phone ? How can you protect yourself ? And should RF emission information be listed on cell phone packaging , and in stores ? First things first : The WHO study did not say `` cell phones cause brain cancer . '' Rather , there is some evidence indicating a possible connection -- and while not conclusive , it warrants further study . Consequently , WHO has now categorized radio frequency electromagnetic fields as a `` group 2B '' possible human carcinogen . Here 's how Ed Yong , head of health information at Cancer Research UK , explained it in his detailed analysis of the WHO announcement : `` Group 2B means that there is some evidence for a risk but it 's not that convincing . This group ends up being a bit of a catch-all category , and includes everything from carpentry to chloroform . '' Dr. Gupta : Cell phones , brain tumors So it