We recently noted how despite any solid science leaning one way or the other, San Francisco was the first government to the nation to require that wireless retailers clearly display the amount of radiation each cell phone puts out. Retailers now have to display this information -- specifically the phone's specific absorption rate (SAR) -- in 11 point type right next to the price. Obviously the wireless industry isn't happy about the extra work and possible bad PR caused by cancer fears, so they're apparently responding by canceling a major trade show in the city after this year:According to the FCC, phones can't have a SAR higher than 1.6 watts per kilogram. Scientific studies so far have not been able to conclude that cell phones cause cancer, though some data seems to indicate that the potential exists for higher cancer rates with extremely heavy use. However, solid data on this front doesn't exist yet -- though several long-term studies (as in thirty years long) are ongoing.