What electromagnetic waves are dangerous for humans?

Our cell phones transmit in the radio/microwave part of the spectrum, and studies are being done to see if they have long term harmful effects. So while all forms of electromagnetic waves can be harmful, the ones usually though of as harmful are Gamma rays, X-rays, and Ultraviolet light.
(Too much sunlight can cause skin cancer and don't look straight at the sun)

Full change in the electric plus system