BREAKING! Alarming Study Reveals That Far-UVC Light Might Not Be as Safe as Previously Believed, Can Cause DNA Damage!
Nikhil Prasad Fact checked by:Thailand Medical News Team May 24, 2025 1 month, 2 weeks, 2 days, 20 hours, 16 minutes ago
Medical News: For the past few years, Far-UVC light—especially the 222-nanometer (nm) wavelength—has been praised as a revolutionary weapon against airborne pathogens like SARS-CoV-2. Dubbed “safe” for use around humans, this special type of ultraviolet light has been rapidly adopted in hospitals, airports, offices, and public places for disinfection purposes. But new scientific evidence is casting a dark shadow over this glowing reputation.
Alarming Study Reveals That Far-UVC Light Might Not Be as Safe as Previously Believed, Can Cause DNA Damage
In a groundbreaking new study conducted by researchers from the University of Edinburgh’s Centre for Inflammation Research-UK and Heriot-Watt University’s Institute of Photonics and Quantum Sciences-UK, Far-UVC light was found to cause significant DNA damage in human lung cells and tracheal tissues—even at low doses previously thought to be harmless. This
Medical News report dives into the critical findings that could change how we view one of the most celebrated infection-control technologies in recent years.
Once Hailed as a Game-Changer, Now Under Scrutiny
Far-UVC light, operating in the range of 200 to 235 nm, has gained popularity due to its proven ability to destroy bacteria and viruses without penetrating the outermost dead layers of human skin or the tear layer of the eyes. It was marketed as being “safe for human exposure” while remaining lethal to airborne pathogens.
However, this new study challenges those assumptions. Using both a krypton-chloride (KrCl) excimer lamp and a highly specialized pulsed laser system, researchers exposed human bronchial epithelial cells and primary human tracheal tissues to different doses of 206 nm and 222 nm Far-UVC light. The doses tested were 5, 25, and 50 mJ/cm²—levels that have often been considered “safe” and are used in real-world disinfection scenarios.
DNA Under Attack
The researchers discovered that even the lowest doses of Far-UVC light triggered harmful effects in human lung cells. Among the most alarming findings:
-Far-UVC light caused direct double-strand DNA breaks, as evidenced by elevated levels of γH2AX (Ser139), a well-known biomarker for DNA damage.
-Both continuous-wave and pulsed exposure to 222 nm and 206 nm light led to the formation of harmful (6-4) photoproducts—lesions in DNA that can prevent proper replication and potentially trigger mutations.
-Human tracheal tissues showed similar damage, confirming that the effects are not limited to isolated cells in a lab dish but also occur in actual human airway tissues.
-These DNA lesions, especially the (6-4) photoproducts, are particularly concerning because they can disrupt cellular function and are known precursors to cancer if not properly repaired.
Cell Death and Toxic
ity
The researchers didn’t stop at identifying DNA damage. They went further to examine how Far-UVC affects overall cell health.
In the days following exposure, the irradiated lung cells demonstrated a significant drop in viability. This was shown using crystal violet staining, which highlighted that irradiated areas contained dead or dying cells. Some of the key findings include:
-In Beas-2B human bronchial cells, 25 mJ/cm² of 222 nm light led to more than a 50% drop in viable cell populations within 48 hours.
-Flow cytometry confirmed a spike in late apoptosis (programmed cell death) at 12 hours post-exposure, with live cell populations plummeting from 82% in controls to as low as 30% in exposed samples.
-Elevated levels of lactate dehydrogenase (LDH) were detected in the culture medium—a sign that the cell membranes had been breached, causing the cells to leak and die.
The Trachea Tells the Same Story
Taking their investigation a step further, the team analyzed pieces of donated human trachea. These tissues were carefully irradiated with both continuous and pulsed Far-UVC at the same energy levels. Just ten minutes after exposure, damage was clearly evident:
-A marked increase in γH2AX-positive cells indicated DNA damage across the upper epithelial layers.
-(6-4) photoproducts were again found in high numbers, affirming that real-world tissues are vulnerable to the same genetic injuries observed in lab-grown cells.
This suggests that the very airways we rely on to breathe—especially in those suffering from respiratory diseases or on ventilators—might be at risk if exposed to Far-UVC disinfection strategies.
Pulmonary Safety Concerns Mount
The findings come at a crucial time, as Far-UVC is being considered for deeper clinical uses, including direct applications in treating lung infections or preventing ventilator-associated pneumonia caused by antibiotic-resistant bacteria.
The authors, led by Dr. Asta Valanciute, Professor Robert R. Thomson, and Professor Kevin Dhaliwal, caution against this rapid enthusiasm. The team stresses that while Far-UVC light does offer strong antimicrobial power, its impact on internal tissues—especially delicate lung linings—requires urgent reevaluation.
Their work clearly demonstrates that even brief exposures to low doses of 222 nm and 206 nm light can:
-Penetrate beyond surface layers
-Disrupt nuclear DNA
-Induce apoptosis
-Reduce tissue viability
-Damage cell membranes
This implies that Far-UVC, far from being completely safe, may carry hidden biological risks when used too close to living tissues, especially those found inside the body.
A Wake-Up Call for Public Health and Safety Regulations
Until now, most safety studies on Far-UVC have focused on the outer layers of the skin and eyes. Based on these findings, many manufacturers, hospitals, and regulatory agencies have proceeded with broad installations in indoor public spaces. However, this new research highlights a potentially dangerous oversight: the assumption that Far-UVC light cannot penetrate deeply enough to harm internal structures.
This study reveals that when the light reaches respiratory surfaces or comes in contact with epithelial cells, it can and does cause damage—subtle, cumulative, and possibly carcinogenic over time.
Given the rising popularity of Far-UVC devices in homes, offices, schools, and even aircraft cabins, this study serves as a much-needed red flag.
Final Thoughts and Urgent Implications
The researchers behind this landmark study strongly advocate for a more cautious approach to Far-UVC deployment. Until comprehensive long-term safety data is available—especially for internal applications—the use of 206 nm and 222 nm light in any setting where it might reach live human tissue should be strictly controlled or reconsidered entirely.
In conclusion, while Far-UVC has immense potential in controlling infectious diseases, this technology is not a free pass. Misuse or overexposure could lead to unintended biological consequences, particularly at the genetic level. The study serves as a timely reminder that even solutions born in the lab must be tempered by thorough real-world validation. Caution, not convenience, should dictate how we proceed with integrating Far-UVC into public health strategies.
The study findings were published in the peer reviewed journal: Scientific Reports.
https://link.springer.com/article/10.1038/s41598-025-02869-0
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