This absolutely depends on the frequency of UVC and the intensity of the lamp. The lamps this post links such as https://aerolamp.net are putting out 222-nm, which is much safer than longer UVC wavelengths and the intensity is well under TLV when placed 8.5ft up (or higher).
They can leak into higher wavelengths. You are really putting a whole lot of trust in manufacturers if you are sitting underneath one of these for decades with unprotected eyes. Not a risk I would take personally (I have glaucoma already, so I'm a bit more sensitive than the average person about eye health)
Kinda like advertising "Asbestos-Free Cereal" isn't it? If someone was marketing a product to me and they were super insistent about how super duper safe it was I would probably start getting suspicious
UV rightfully raises concerns about skin damage, highlighting that they're careful about excluding the harmful parts would be helpful for customers who either know just enough to think "UV bad" or to those who wonder how narrow their filters are.
Imo a better analogy would be selling a circular saw with a safety mechanism and hiding the latter in the specsheet.
This absolutely depends on the frequency of UVC and the intensity of the lamp. The lamps this post links such as https://aerolamp.net are putting out 222-nm, which is much safer than longer UVC wavelengths and the intensity is well under TLV when placed 8.5ft up (or higher).
See https://www.faruvc.org for more on eye safety.