My mother was a geologist, so I grew up, around "shortwave" UV lamps.

These trigger much brighter fluorescence in rocks and minerals (and blacklight posters) than your average blacklight bulb, but they can give you a nasty sunburn, and damage your eyes (we had to wear special goggles, when we used these lamps). I never heard about "altering DNA," but maybe that's where the sunburn comes from.

It's pretty easy to get "standard" blacklight LEDs (about 400nm), but less easy to get "shortwave" blacklights (250nm). The 250-300nm lamps are the "sterilizing" lamps.

Maybe there's some band in there that is "safe." I dunno. I notice that wavelengths are not mentioned in the story.