To be clear, I'm not saying whether or not UV LEDs in an empeg is or is not a good idea.

"Black Light" is common term for UV lights. Some UV lights have a filter to filter out the visible blue light that the lamps also tend to produce. So some UV lights look quite dim, while actually emiting large amounts of UV.

It is all about power, distance and exposure time. Increase any of those and the risk goes up (and with distance the increase isn't linear).

I have one of those insect zappers in my kitchen, which has UV tubes in it. But then I don't spend lots of time looking at it and we don't stand close to it for long periods of time.

It looks like the Hyundai were just playing around with the idea, I can't see that really happening. UV also ages plastics, so pumping it into a car interior, even if it is only when it is locked with no one in it doesn't sound like a great idea...