"The following question was answered by an expert in the appropriate field:

Q
I work in a hospital, and I am pregnant now. I would like to ask you if ultraviolet C (UVC) rays could harm my baby? I was in a room where a UVC lamp was running, but I was in the room for only a few seconds."
https://hps.org/publicinformation/ate/q11765.html


"2016 Health Physics Society" claims:
"Because the UVC radiation does not penetrate the skin, there will be no harm to you or your baby regardless of the time you were exposed to the UVC light. As a public health message, other types of UV radiation (UVA and UVB) are considered hazardous and one should minimize the amount of time of exposure. According to the World Health Organization (WHO), UVA radiation is associated with skin cancers (http://www.who.int/uv/health/en/)."
https://hps.org/publicinformation/ate/q11765.html

Whereas the WHO says quite the opposite about UVC:
"What is the difference between UVA, UVB and UVC?
The three types of UV radiation are classified according to their wavelength. They differ in their biological activity and the extent to which they can penetrate the skin. The shorter the wavelength, the more harmful the UV radiation. However, shorter wavelength UV radiation is less able to penetrate the skin.

Short-wavelength UVC is the most damaging type of UV radiation. However, it is completely filtered by the atmosphere and does not reach the earth's surface.

Medium-wavelength UVB is very biologically active but cannot penetrate beyond the superficial skin layers. It is responsible for delayed tanning and burning; in addition to these short-term effects it enhances skin ageing and significantly promotes the development of skin cancer. Most solar UVB is filtered by the atmosphere.

The relatively long-wavelength UVA accounts for approximately 95 per cent of the UV radiation reaching the Earth's surface. It can penetrate into the deeper layers of the skin and is responsible for the immediate tanning effect. Furthermore, it also contributes to skin ageing and wrinkling. For a long time it was thought that UVA could not cause any lasting damage. Recent studies strongly suggest that it may also enhance the development of skin cancers."
http://www.who.int/uv/faq/whatisuv/en/index2.html

Obviously, there are studies about UVA and skin cancer but not UVC and skin cancer.
It's quite contradictive if it is stated that UVC is the "most damaging UV radiation" (WHO) on the one side and giving only UVA a certified assurance of a probability of skin cancer generation. This is not plausible.

The "Health Physics Society" concludes wrongly that UVC is NOT dangerous: "Because the UVC radiation does not penetrate the skin, there will be no harm to you or your baby regardless of the time you were exposed to the UVC light."
If the skin is not penetrated by UVC radiation - according to the "Health Physics Society" why is UVC radiation the most damaging UV radiation - according to the WHO?


Health Physics Society
1313 Dolley Madison Boulevard, Suite 402
McLean, Virginia 22101
Phone: 703-790-1745
Email: hps@BurkInc.com
https://hps.org/disclaimer.html

https://www.med.navy.mil/sites/nmcp...ltraviolet-radiation-technical-guide.pdf

https://solarlight.com/wp-content/u...tion-surface-measurements_whitepages.pdf

Jesse G. Dillon Richard W. Castenholz
SCYTONEMIN, A CYANOBACTERIAL SHEATH PIGMENT, PROTECTS AGAINST UVC RADIATION: IMPLICATIONS FOR EARLY PHOTOSYNTHETIC LIFE
Journal of Phycology Volume 35, Issue 4
First published: 02 September 2002
https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1529-8817.1999.3540673.x

"Abstract
During the Precambrian, ultraviolet (UV) radiation reaching the Earth’s surface, including UVC wavelengths (190–280 nm), was considerably higher than present because of the lack of absorbing gases (e.g. O2 and O3) in the atmosphere. High UV flux would have been damaging to photosynthetic organisms exposed to solar radiation. Nevertheless, fossil evidence indicates that cyanobacteria-like ancestors may have evolved as early as 3.5 × 109 yr ago, and were common in shallow marine habitats by 2.5 × 109 years ago. Scytonemin, a cyanobacterial extracellular sheath pigment, strongly absorbs UVC radiation. Exposure to high-irradiance conditions caused cells to synthesize scytonemin and resulted in decreased UVC inhibition of photosynthetic carbon uptake. It was further demonstrated that scytonemin alone was sufficient for substantial protection against UVC damage. This represents the first experimental demonstration of biological protection against UVC radiation in cyanobacteria. These results suggest that scytonemin may have evolved during the Precambrian and allowed colonization of exposed, shallow-water and terrestrial habitats by cyanobacteria or their oxygenic ancestors."

Quite the opposite!

J. Marvin Herndon1*, Raymond D. Hoisington2 and Mark Whiteside3
Deadly Ultraviolet UV-C and UV-B Penetration to
Earth’s Surface: Human and Environmental Health
Implications
in: Journal of Geography, Environment and Earth Science
International 14(2): 1-11, 2018;
ISSN: 2454-7352
http://www.nuclearplanet.com/uvc2.pdf

1 Transdyne Corporation, 11044 Red Rock Drive, San Diego, CA 92131, USA.
2 iRay SpectraMetrics, 2760 Adrian Street, Turlock, CA 95382, USA.
3 Florida Department of Health in Monroe County, 1100 Simonton Street, Key West, FL 33040, USA.