Sunburn is a sign of short-term overexposure to UV light, while premature aging and skin cancer are long-term effects. Overexposure to UV radiation can have serious health consequences, including cancer. Medium wave UV (UV-B) rays cause skin burns, erythema (reddening of the skin), and darkening of the skin. Long-term exposure increases the risk of skin cancer.
Sunlight is the main source of UV radiation, although it only makes up a small part of the sun's rays. Longwave UV (UV-A) radiation represents up to 95% of the UV radiation that reaches the Earth's surface. Short-wavelength UVC radiation is the most dangerous type of UV radiation, but it is completely filtered by the atmosphere and does not reach the Earth's surface. Comprehensive protection is essential when working with UV light boxes for more than a few seconds.
People who may be exposed to artificial sources of UV rays at work should take appropriate safety precautions, including wearing protective clothing and UV protectors and filters. The Journal of Chemical Health & Safety published an evaluation of exposure to UV rays produced by transilluminating light boxes (PDF) that explains hazards, controls and some common errors. Just as visible light is made up of different colors that appear in a rainbow, the spectrum of UV radiation is divided into three regions called UVA, UVB and UVC. Those who may be exposed to UV radiation must be trained on the hazards, signs and symptoms of exposure, and proper use of equipment that produces UV rays.
Environmental Health & Safety can help measure UV emissions and evaluate the UV protection of personal protective equipment. If there is a possibility that the eyes and face are exposed to UV radiation, a polycarbonate face protector with ANSI Z87.1-1989 UV certification should be used to protect the eyes and face.