Source: USA Today Author: Staff San Francisco, a U.S. trendsetter on many social issues, voted Tuesday to require retailers to post notices on how much radiation is emitted by cellphones they sell. The Board of Supervisors approved the ordiance, believed to be the first of its kind in the United States, despite opposition from the cellphone industry, which argued that it could impede sales and mislead consumers into believing some phones are safer than others. There's no scientific consensus on the dangers of cellphone radiation, but the Federal Communications Commission sets exposure limits. Cellphones can't have a specific absorption rate (SAR) -- the amount of radio waves absorbed by the user's body -- greater than 1.6 watts per kilogram. The Environmental Working Group, a private government watchdog group, says cellphone users can take steps to reduce exposure by, among other things, texting and listening rather than talking and by using a headset or speaker. Mayor Gavin Newsom, an avid iPhone user who is running as the Democratic nominee for California's lieutenant governor, is expected to sign the ordinance into law after a 10-day comment period, reports the Associated Press. "In addition to protecting the consumers' right to know, this legislation will encourage telephone manufacturers to redesign their devices to function at lower radiation levels," Gavin said in January in proposing the legislation. Gavin said more research is needed on cellphone safety but cited recent studies that indicate long-term exposure to cellphone radiation can increase the risks of brain and mouth cancer, among [...]