Radiation

Large doses of any radiations, ionizing or not, can be dangerous. Too much sunlight, for example, can be blinding. Lasers can deliver such intense beams of light that they can burn through metal, not to mention human flesh. High levels of microwaves in ovens can cook meats and vegetables. On the other hand, as far as anyone has been able to determine, small amounts of any kind of radiation are harmless, including the ionizing radiations from radioactivity. That's just as well, because there are unavoidable, natural radioactive materials all around us.

Depending on the energy, intensity, and type of radiation, radiation may be harmful or quite harmless. It is all a matter of what kind and how much.