Radiation causes damage to living cells by ionization. When electrons are torn from the molecules making up DNA, it causes replacement cells to be altered from what they should be. Two things are required to make radiation harmful: Frequency and intensity. The frequencies at which cell phones or bluetooth devices operate are orders of magnitude lower than that required to cause ionization. Intensity, or power, of cell phones or bluetooth devices is millions of times too low to cause even localized heating of flesh. A bluetooth device hanging on your ear, which operates at the same frequency as your microwave oven, is putting out the power equivalent of a gnat compared to a whale.
The Board of Supervisors in San Francisco should be ashamed of their unanimous vote to require the posting of power levels of cellular phones. The city is surrounded by bright people who actually understand radiation—Silicon Valley to the south, UC Berkeley, the Lawrence Livermore National Laboratory, and Stanford University. People at those places know that it is far more dangerous to lie with your skin exposed to sunlight on the warm sand of a beach than it is to use a cell phone. Ultraviolet light, cosmic rays, and X-rays cause ionization; cellular radio waves don’t. Being at high altitude exposes you to even more radiation from the cosmos. Hiking in the High Sierra exposes a person to radiation from the atomic decay present in granite. (An aside: Are granite countertops contributing to cancer deaths? There’s a whole new regulation pursuit for the Board of Nannies!)
San Francisco’s government is straitjacketed by its perceived mandate to control and manage its citizens’ lives at all cost, with total disregard of scientific evidence. In the supervisors’ minds the citizens must be protected from evil corporations that are so eager to kill all of their customers in their ardent pursuit of profit. The city’s principal source of income, like that of Athens, Greece, is tourism: Keep it attractive and amusing—a playground. The Board of Supervisors should be recruited from Disneyland, not from home-grown despots.
Idiocy is hard to fight. Especially when it has the imprimatur of official decree.
A couple of interesting links: http://www.cancer.org/Cancer/CancerCauses/OtherCarcinogens/MedicalTreatments/radiation-exposure-and-cancer