Is your cell phone a known carcinogen? Do cell phones give you cancer?  Well, the precautionary principle contends unless you can prove cell phones can't give you cancer, then they are a concern.  Fortunately, the precautionary principle isn't overused by everyone (though when it is, the politically like-minded dismiss it as policy disagreement and not being anti-science) but any time you have an anti-science hotbed, it will get trotted out.

Welcome to San Francisco, which makes Seattle look positively lucid in its quest to mollify every anti-science hippie contingent - except naked old guys, who suddenly discovered their libertarian streak when a city councilman asked them to sit on a towel when they make us lose our appetite in a Castro City restaurant.

San Francisco is kind of famous for overstepping the law just like California is generally famous for adopting crackpottery as its official state home decor.  They have decided that, despite any evidence linking cell phones to cancer, they will require cell phone companies to have warning labels about the risks of cancer.  Former Frisco mayor Gavin Newsom, no stranger to anti-science fringe-ness, has supported the idea for years because of the precautionary principle and he is Lt. Governor now, so people must like that stuff. Even local mainstream Frisco news affiliates, not exactly a breeding ground for future Fox News correspondents, ridiculed him (San Francisco's Faddish Family-Man-in-Chief) at the time, though mostly for invoking concerns about his daughter about cell phone radiation yet followed the Hollywood crowd in not giving his kid vaccines.  Oh, and for implying his adorable cherub might ever attend a public school and therefore need warning labels about cell phone radiation.

Kookiness won't die.  Despite no evidence of harm, cell phone towers have a difficult time going up in San Francisco due to the hysteria.  The CTIA, the wireless trade group, has moved its annual convention out of the city and asked the U.S. District Court for the Northern District of California for an injunction to stop the city from enforcing the Cell Phone Right-to-Know ordinance on First Amendment grounds.   The city changed tack to the current ridiculous rule when the CTIA sued last year over the city passing an ordinance forcing companies to provide warning labels in general.

Basically, they don't want to be forced to distribute anti-science, misleading information and they  state the city is overstepping its authority saying it can regulate emissions from cell phones, a duty it would seem is reserved exclusively for the FCC.