The National Council on Radiation Protection and Measurements reports that among those U.S. workers exposed to radiation while on the job, flight crews get the largest annual effective dose. That’s not a good thing. Ultraviolet (UV) radiation is invisible to the human eye but can burn the skin and cause skin cancer including melanoma as well as damage to one’s eyes. The chronic effects of UV exposure can be serious, even life threatening, and include premature aging of the skin,