The primary harmful effect of infrared radiation (IR) is thermal injury, but scaling and hyperpigmentation of skin can also occur, even if no pain is felt. IR-proof goggles can be required in certain industrial environments in which high exposure to invisible infrared radiation can cause blindness or damage to the eyes. Although skin cancer is not directly connected to IR exposure, elevated skin temperatures can reduce the efficiency of DNA repair and promote skin cancer initiated by other causes.
Sunlight is the main source of infrared radiation, but infrared saunas and cabins, tungsten lamps, xenon arc lamps, industrial IR lamps and iron melt from steel mill furnaces are additional sources. A variety of workers can be affected by exposure to infrared radiation, including glass blowers, smelters, firefighters and kiln workers. Industrial and medical lasers also emit levels of infrared radiation that that can place workers at risk.
Infrared radiation does not penetrate deeply into tissue, and the primary targets of IR damage are the skin and eyes. Due to the transparency of the ocular media, the retina is particularly susceptible to damage from IR in the lower wavelengths. At the higher wavelengths, the pigmented iris and lens will absorb the infrared radiation, and it is believed this may play a part in the development of lenticular opacities.