“UVC lamps used for disinfection purposes may pose potential health and safety risks depending on the UVC wavelength, dose, and duration of radiation exposure,” the FDA stated in this week’s report.
The FDA said there is limited knowledge about the effectiveness of these UVC lights when it comes to inactivating the novel coronavirus, and in some cases, the lamps have the potential to cause harm.
“The effectiveness of UVC lamps in inactivating the SARS-CoV-2 virus is unknown because there is limited published data about the wavelength, dose, and duration of UVC radiation required to inactivate the SARS-CoV-2 virus,” the report stated. “It is important to recognize that, generally, UVC cannot inactivate a virus or bacterium if it is not directly exposed to UVC. In other words, the virus or bacterium will not be inactivated if it is covered by dust or soil, embedded in porous surface or on the underside of a surface.”
The report, released Wednesday, said UVC radiation has been used in some cases to disinfect water, air and nonporous surfaces. It has also been used for decades to stop the spread of tuberculosis and certain bacteria, which led to UVC lamps often being called “germicidal” lamps, according to the agency.
UVC radiation has been shown to attack the surface protein of SARS-coronavirus leading to inactivation of the virus, but that is different to the current SARS-CoV-2 virus that causes COVID-19, according the report.
Aside from needing direct exposure to a virus on an unsoiled surface, the FDA stated that UVC radiation has other limitations with inactivating viruses. Many home-use UVC lamps are low dose, so it requires a longer surface exposure time with the light to inactivate the virus or bacteria.
UVC radiation is often used to disinfect the air through ducts, health experts told Fox News. This type of disinfection is typically used in hospitals when no humans are present.
“This is the safest way to employ UVC radiation because direct UVC exposure to human skin or eyes may cause injuries, and installation of UVC within an air duct is less likely to cause exposure to skin and eyes,” the FDA added in Wednesday’s report.
The report also cautioned about the risks of using UVC light and said direct exposure can cause burns to the skin and eye injury. Another concern mentioned is ozone, which is emitted from the UVC lamps and can irritate airways, according to the FDA report. Materials like plastic and dyed textiles can be degraded by UVC light, and some lamps can even contain mercury, which is extremely toxic and poses a health threat if the lamp is broken, the FDA cautioned.
The FDA further cautioned that there are different types of UV lamps, with different applications. Pulsed xenon lamps, which are filtered to emit UVC radiation, are used at times in hospitals to treat environmental surfaces such as operating rooms when humans are not present. Light-emitting diodes (LEDs) are also becoming more available, emit a very narrow wavelength band of radiation, and don’t contain mercury. However, this lamp may be less effective for germicidal applications, the agency stated.
Those who choose to use these lamps, therefore, should be cautious, the FDA warned.
“Avoid direct skin exposure to UVC radiation and never look directly into a UVC light source, even briefly. If customers identify a problem with a UVC lamp, they can report it to the manufacturer and the FDA.”