UV Filters, UVC Hazards, and Photoprotection: What Everyone Should Know

Prepared by

Dr. Abhinandan Chowdhury (Rocky)

PhD (Toxicology, AU) | MSc (Analytical Bioscience, UK) | BSc (Biotechnology, AU)

Head of Toxicology and Compliance, VeganicSKN Australia

Executive Summary

When most people think about sunscreen, they imagine sunny beaches and summer holidays. But UV radiation is everywhere — in our cities, in our workplaces, and even in industrial settings like welding bays.

This report explains:

• The three types of UV radiation and why they matter

• How different sunscreen ingredients work

• The hidden UVC danger for welders

• Why zinc oxide may be the gold standard in skin protection

• What you should look for in a safe, effective sunscreen

Our goal is simple: help you protect your skin — whether you’re under the sun, in the workshop, or anywhere UV can reach you.

1. Understanding UV Radiation

Ultraviolet (UV) radiation is a type of invisible light from the sun and some artificial sources. It comes in three main forms:

• UVA (320–400 nm) – Makes up 95% of UV reaching the Earth. It penetrates deep into the skin, causing premature aging, wrinkles, and pigmentation. UVA damage is invisible, penetrating deeper into the skin where it accelerates aging and increases the risk of skin cancer without necessarily causing redness.

• UVB (280–320 nm) – The main cause of sunburn and skin cancers. It damages the skin’s surface layers and directly alters DNA. UVB damage is visible — it causes redness and burning that you can see and feel soon after exposure.

• UVC (200–280 nm) – The most dangerous type. Normally blocked by the ozone layer — but it can be generated artificially by welding arcs and certain industrial lamps. UVC damage is both intense and immediate, with peak harm around 270 nm, and can cause serious injury to the eyes and skin in seconds.

Key fact: While most people only think about UVA and UVB, workers in certain industries face UVC exposure, which is far more damaging to skin and eyes.

2. How Sunscreens Work

Sunscreens protect us by filtering out harmful UV rays. There are two main categories:

Chemical (Organic) Filters

• Absorb UV rays and release the energy as heat.

• Common examples: oxybenzone, avobenzone, octocrylene.

• Pros: Lightweight feel, transparent on skin.

• Cons: Can absorb into the bloodstream, some disrupt hormones, some harm marine life, and some break down in sunlight.

Mineral (Inorganic) Filters

• Sit on top of the skin, reflecting and scattering UV light.

• Main ingredients: zinc oxide and titanium dioxide.

• Pros: Broad-spectrum protection, very stable, minimal skin absorption.

• Cons: Can leave a white cast (though modern micronized and tinted versions reduce this).

The Sunscreen Paradox

While sunscreens are designed to protect against burns and skin cancer, emerging research shows a more complex picture.

·         In a large UK Biobank study, sunscreen use was surprisingly associated with a more than twofold increase in skin cancer risk, possibly because users stayed in the sun longer without burning.

·         McGill University researchers have described this as a “false sense of security,” warning that sunscreen prevents redness (UVB effect) but does not always prevent the deeper, invisible UVA damage that drives melanoma.

·         A Swedish cohort study found that people who avoided sun exposure had twice the all-cause mortality compared to frequent sunbathers. This suggests that complete avoidance of sunlight may carry its own health risks, although the study did not test sunscreen directly.

Taken together, these studies highlight a paradox: chemical sunscreens can reduce burning but may encourage overexposure, leaving people vulnerable to hidden UVA damage.

This is why zinc oxide, with its broad coverage of UVA, UVB, and even UVC, is increasingly seen as a safer, more reliable option.

3. Why Zinc Oxide Stands Out

Zinc oxide is one of the only sunscreen ingredients that:

• Protects across UVA, UVB, and part of the UVC spectrum

• Maintains effectiveness in sunlight without breaking down

• Has an excellent safety profile — does not significantly penetrate skin

Emerging research even shows zinc oxide in certain engineered forms can block up to 97% of UVC in lab settings. While this doesn’t replace PPE for welders, it could be an extra layer of defense for exposed skin.

4. The Hidden Hazard: UVC in Welding

Arc welding produces intense UV radiation, including UVC. Studies show that at just half a metre from the welding arc, the maximum safe daily exposure can be as short as 1.4 seconds without protection.

Risks to welders and nearby workers include:

• “Arc eye” (painful inflammation of the cornea)

• Skin burns and redness

• Long-term increased skin cancer risk

Primary protection will always be PPE: helmets, shields, gloves, and clothing. Thick, tightly woven clothing — such as denim, canvas, or certified UV-protective fabrics — can block nearly all UVB and most UVA radiation, though a small amount of longer-wavelength UVA can still pass through. This makes it an excellent first-line defense for the body. However, exposed skin on areas like the face, neck, and wrists should be covered with a broad-spectrum zinc oxide sunscreen for additional protection. Secondary protection could include zinc oxide-based sunscreen for exposed areas like the neck and lower face.

5. Environmental Considerations

Some sunscreen chemicals — notably oxybenzone and octinoxate — are linked to coral bleaching and are banned in Hawaii, Key West, and other sensitive marine areas.

Better choices for people and the planet:

• Mineral sunscreens (non-nano zinc oxide, titanium dioxide)

• Reef-safe certified formulas

• Avoid aerosol sprays to reduce inhalation risk and environmental spread

6. How to Choose a Sunscreen

When buying sunscreen, check for:

1. SPF 30 or higher – SPF protects mainly against UVB.

2. “Broad Spectrum” on the label – ensures UVA coverage.

3. Zinc oxide (ideally 15–25%) for the most complete protection.

4. Water resistance if you’re sweating or in water.

5. Avoid unnecessary additives like heavy fragrances or alcohol (can irritate skin).

7. Final Takeaways

• UV protection isn’t just for sunny days at the beach. It’s also a workplace health measure.

• Zinc oxide is the most reliable all-around UV filter, with potential UVC benefits.

• For welders and other high-risk workers, think beyond PPE — consider skin protection for uncovered areas.

• Choosing the right sunscreen also protects our environment.

Your skin is your largest organ. Protect it every day, in every setting.

Note: This content draws on data and interpretations from multiple peer-reviewed sources, and incorporates insights provided by Dr Denis Dudley

References:

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2.       Diffey, B. L., Tanner, P. R., Matts, P. J., & Nash, J. F. (2000). In vitro assessment of the broad-spectrum ultraviolet protection of sunscreen products. Journal of the American Academy of Dermatology, 43(6), 1024–1035. https://doi.org/10.1067/mjd.2000.109291

3.       Gabros, S., Patel, P., & Zito, P. M. (2025). Sunscreens and photoprotection. StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK537164/

4.       Takahashi, J., Nakashima, H., Fujii, N., & Okuno, T. (2020). Comprehensive analysis of hazard of ultraviolet radiation emitted during arc welding of cast iron. Journal of Occupational Health, 62, e12091. https://doi.org/10.1002/1348-9585.12091

5.       Tarasi, S., & Morsali, A. (2021). Fabrication of transparent ultraviolet blocking films using nanocomposites derived from metal-organic frameworks. Journal of Alloys and Compounds, 868, 158996. https://doi.org/10.1016/j.jallcom.2021.158996

6.       The Medical Letter. (2025, June 23). Sunscreens. The Medical Letter on Drugs and Therapeutics, 67(1731), 97–102.

7.       Lindqvist, P. G., Epstein, E., Landin-Olsson, M., Ingvar, C., Nielsen, K., Stenbeck, M., & Olsson, H. (2014). Avoidance of sun exposure is a risk factor for all-cause mortality: Results from the Melanoma in Southern Sweden cohort. Journal of Internal Medicine, 276(1), 77-86. http:/doi.org/10.1111/joim.12251

8.       Alli, S., LeBeau, J., Hasbani, A., Lagacé, F., Litvinov, I. V., & Peláez, S. (2023). Understanding the perceived relationship between sun exposure and melanoma in Atlantic Canada: A consensual qualitative study highlighting a “sunscreen paradox”. Cancers, 15(19), 4726. https://doi.org/10.3390/cancers15194726

9.       McGill University. (2023, October 24). The sunscreen paradox: McGill University researchers warn of ‘false sense of security’. McGill Newsroom. https://www.mcgill.ca/newsroom/channels/news/sunscreen-paradox-mcgill-university-researchers-warn-false-sense-security-352205

10.    Hasle, G. (2019, November 14). Sunscreen and malignant melanoma. Tidsskrift for Den norske legeforening. https://tidsskriftet.no/en/2019/11/kronikk/sunscreen-and-malignant-melanoma