Sure, enough of almost anything is dangerous. NIR is much safer than the visible spectrum at the same power levels. The threshold for a few minutes of high-int

Sure, enough of almost anything is dangerous. NIR is much safer than the visible spectrum at the same power levels. The threshold for a few minutes of high-intensity NIR increasing your chance of eventual cataracts is staring at an NIR source 10x brighter (w/cm^-1) than the sun integrated across all its wavelengths. The threshold for sun-colored wavelengths causing eventual cataracts above the baseline from a few minutes of staring is under 1x. Also worth noting, very very near IR (basically red, though we can't see it) doesn't quite enjoy those same properties, and during their time working with hot metal you'd expect a lot of energy in that band. Also worth noting, many steel workers are exposed to dangerous amounts of visible light too. I absolutely believe that they can get enough NIR to cause problems, but if I wanted to try to prove that NIR specifically causes their problems to somebody else then I'd want to try to account for that fact (and for incidental welder exposure, ...).