The controversy over whether radiation from cell phones can cause brain and mouth cancers has intensified now that the Environmental Working Group has posted an online tool that enables people to see levels of radiation emitted by 1,200 cell phones. Among the top-ten highest emitters are the popular Blackberry and Motorola models. Traffic to the site displaying the radiation rankings was so large that the Environmental Working Group — which works to protect children from toxic chemicals and 
products — had to scramble to keep the site from crashing. The U.S. Food and Drug Administration says on its Web site that “the weight of scientific evidence has not linked cell phones with any health problems.” But the Environmental Working Group, after commissioning a review of 200 health reports, said that recent studies suggest a 50 percent to 90 percent increased risk of rare brain and mouth tumors among frequent and long-term cell phone users. The group is particularly concerned about long-term use by children and teenagers, who account for a large share of the 270 million cell phone users in the U.S.