The skin and the eyes are the organs most at risk from the effects of exposure to UV radiation, and it is not only welders who are at risk, but other workers in the vicinity who may also be exposed to radiation from nearby welding or cutting activities.
Erythema is a photochemical response of the skin to UV-B and UV-C, and results in a reddening of the skin, as in sunburn
The most well known, and probably the most frequently suffered, effect from welding arcs is 'Arc eye' or 'welders flash' and this is caused by the action of UV-B and UV-C radiation on the outer eye.
Bright light, or glare, does not itself present a hazard to health, since discomfort occurs at a very small percentage of the illumination level required to cause damage, and the natural response is to close the eyes or shield them or turn away from the glare.
In visible light the major hazard is from blue light 400-500nm.
The intense heat of IR from both electric arc and fuel gas processes can cause thermal burns to the skin and has the potential to cause eye damage in the form of retinal burns and cataracts.