Final answer:
The harmful light rays produced during welding are ultraviolet (UV) and infrared (IR) rays, which can cause eye conditions like welder's flash and cataracts, necessitating the use of protective gear.
Step-by-step explanation:
The two types of light rays produced when welding that can harm the eyes are ultraviolet (UV) and infrared (IR) rays. High intensity UVB light from welding can lead to eye conditions such as welder's flash (photo keratitis or arc eye) and potentially cataracts. These are serious medical issues that emphasize the need to wear proper safety gear such as welder's goggles or helmets with appropriate filters. The electric arc generated during welding is capable of emitting high-energy electromagnetic radiation that can burn the retina if eyes are unprotected. Furthermore, due to the thermal energy released, these rays can even be felt on exposed skin a few meters away and seen for kilometers.