The fact that the CTIA is suing San Francisco over an ordinance that will require publication of cell phone radiation levels in stores is good. The CTIA explains that the new SF ordinance steps on the Federal Communications Commission's ability to decide what's safe.
Besides, California already has a problem with information disclosure. For example, people may walk into an apartment displaying a big sign in the lobby saying that the residence is loaded with chemicals known to cause cancer.
California's attitude with cancer-causing agents originates from Proposition 65, a 1986 law that requires warning labels for anything containing chemicals known to cause cancer. The San Francisco cell phone radiation law is an example of useless information to the ordinary buyer. Radiation levels cannot be compared to calorie counts displayed in restaurants where people would sort of know what is too much.
The FCC already regulates cell phone radiation. It requires phones to go below Specific Absorption Ratio of 1.6 watts per kilogram. But people also have to consider other things like how the phone is held, whether a case is used and the amount of time spent on the phone. And most importantly, there is no proof that cell phone radiation causes cancer.