Friday 14 May 2021

Applying UV light to common disinfectants makes them safer to use

Over 400 common disinfectants currently in use could be made safer for people and the environment and could better fight the COVID-19 virus with the simple application of UVC light.


Benzalkonium chloride (BAK) is the most common active ingredient in many disinfectants regularly used in hospitals, households, and food processing plants to protect against a wide range of viruses and bacteria -- including all strains of SARS-CoV-2, the coronavirus that causes COVID-19 -- but its toxicity means that it cannot be used in high concentrations. It also means that products containing BAK are harmful to humans and the environment.


Researchers have discovered that the chemical's toxicity could be fully neutralized using ultraviolet light (UVC) when tested on cultured human corneal cells.


While an important ingredient for a disinfectant's efficacy, BAK is a severe human skin and eye irritant. The chemical's high toxicity limits the ability to use products with a high concentration of BAK to better protect against harmful viruses and bacteria. High levels of BAK residue are also harmful to the environment, proving especially toxic to fish, aquatic invertebrates, and birds.


After exposing a BAK solution to germicidal ultraviolet-C lamps, they applied the solution to cultured human corneal cells for five minutes and analyzed for cell metabolic activity and viability. The BAK solutions were completely neutralized by UVC as the solutions no longer harmed the cultured human corneal epithelial cells.




Manlong Xu, Jacob G. Sivak, David J. McCanna. Neutralization of the eye and skin irritant benzalkonium chloride using UVC radiation. Cutaneous and Ocular Toxicology, 2021; 1 DOI: 10.1080/15569527.2021.1902339


Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (

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