http://www.osha.gov/Publications/OSHA3166/osha3166.html
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Occupational Safety and Health Administration, U.S. Department of Labor
Sunlight contains ultraviolet (UV) radiation, which causes premature aging of the skin, wrinkles, cataracts, and skin cancer. The amount of damage from UV exposure depends on the strength of the light, the length of exposure, and whether the skin is protected. This article discusses self-examination to detect skin cancers and provides tips on how to block out UV rays.