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Demand for ultraviolet (UV) wands has grown rapidly, promoted with government approval as coronavirus killers. But the FDA recently released safety warnings for consumers following reports of eye injuries, skin burns, and other safety concerns from UV lamps.
For decades, UV light has been a powerful tactic for disinfecting large institutional settings like offices and hospitals. UV kills several known respiratory viruses by destroying their outer proteins. Researchers have found that it can kill the original SARS-CoV coronavirus, and it may also work against SARS-CoV-2, the virus responsible for the COVID-19 pandemic.
Although widely used to disinfect workspaces, UV light is not used in occupied areas, according to a June report published in Nature. That’s because it can cause skin and eye damage. Some think a switch to UVC light could change that -- others are less sure.
Authors of the Nature study say UVC light can’t penetrate the skin as deeply as other forms of UV light, making it safer. Some are calling for UVC lamps in occupied public settings.
The FDA and others are warning that UVC light is not safe for human use in some cases.
Despite safety concerns, UVC hand wands continue to be sold to US homes. Manufacturing groups warn that the safety features and operating instructions on some of these devices fail to live up to industry standards.
What Is UV Light?
Ultraviolet light is invisible light. It has a higher electromagnetic frequency than visible light. Sunlight is how most people are exposed to UV, which can cause different skin cancers, including carcinoma and melanoma.
The sunlight on Earth has two types of UV light: UVA and UVB. These lights are known to be dangerous to human skin. But some scientists are now asking if another UV light, UVC, could be both effective at stopping coronavirus and safe for human use.
The sun produces UVC light, but our atmosphere blocks it out, said MedicineNet medical author William C. Shiel Jr., MD, FACP, FACR. People are not exposed to this light under usual circumstances.
Does UVC Light Work Against Coronavirus?
There aren’t enough studies to say whether this frequency of light works against the novel coronavirus SARS-CoV-2. But UV radiation is known to kill other coronavirus types, as well as several other germs.
For UV light to disinfect, a microbe must be directly exposed to the radiation. Soil and other barriers can prevent the light from reaching microbes in some situations.
Are UVC Lamps and Wands Safe?
UVC light is potentially more dangerous than UVA or UVB, Dr. Shiel said. This form of UV has the highest frequency, which also makes it the most high-energy type of UV light.
This concern is borne out by a recent industry warning from the international electronics testing and certification corporation UL. You may recognize their small logo on everything from the device you are reading this article on to the lightbulb above your head, to your toaster oven; UL has been a global testing and safety authority for electronic devices for decades.
UL has refused to allow their safety mark on new UVC wands, citing concerns. They specifically warn of:
- Devices that do not properly contain UVC radiation
- Over-exposure, which can damage eyes and skin
- Improper use by untrained consumers
- Inadequate product designs that allow consumers to use products in potentially harmful ways
- Lung risks, as some UVC devices produce ozone, which can irritate the lungs, particularly in people with asthma or allergies
The government adds to this list, warning that UVC lamps can contain mercury, a powerful toxin. The FDA also warns that some plastics, dyed textiles and other materials can be degraded by UVC.
Consumers should also be aware of the range of UVC lamp standards on the market now, the FDA says. Some of these use broad-spectrum UV light, or a combination of UV, visible light and infrared radiation. These differences can affect the disinfecting power of the light.
“There is some evidence that excimer lamps, with peak wavelength of 222-nm may cause less damage to the skin, eyes, and DNA than the 254 nm wavelength, but long-term safety data is lacking,” according to the FDA statement.
Indeed, a 2017 study published in Radiation Research found such a device at such a frequency could effectively kill MRSA and other bacteria without harming a human skin model.