This post was sponsored by ALS.

A little over a year ago, terms like coronavirus, COVID-19, pandemic, social distancing, and quarantine became part of our daily vernacular. These terms have dominated the daily news cycles, work practices, and interactions with friends and family, and spurred our irrational stockpiling of goods like toilet paper and disinfectants.

Disinfectants in particular have been central in the fight to regain control of our daily lives both at home and at work. Early in the pandemic, EPA established List N, a list of disinfectants for use against SARS-CoV-2. Originally a simple spreadsheet, List N has since evolved into an interactive database. A quick scan of the chemicals listed on the EPA website reveals that a common active ingredient, quaternary ammonium, is present in most of the products. Quaternary ammonium cations, also known as quats, represent a class of chemicals that include a positively charged nitrogen atom surrounded by organic molecules or alkyls. The most common chemicals used under this class of compounds is benzalkonium chloride or alkyldimethylbenzylammonium chloride, which are sometimes referred to as BZK, BAC, or BAK.

Well-known companies that produce cleaning products have incorporated BAC chemicals as their main ingredient in several viral or bacterial disinfectants. These commercially available products are being deployed by both professional decontamination companies and consumers at varying concentrations under the assumption that they have been approved for consumer use and proven effective against most viruses and bacteria. History has shown that although some products may not cause harm to individuals, their advertised effectiveness may not hold true for all applications.

For example, in 2016, the Food and Drug Administration banned the use of triclosan and a number of other antimicrobial chemicals from being sold in consumer products advertised as disinfectants. FDA acted after studies determined that these chemicals, used in soaps, shampoos, and over-the-counter antiseptics, were not effective biocides. However, due to the COVID-19 pandemic, FDA had delayed making a final decision regarding the use of BACs. (For more information, refer to guidance and a news release from FDA.)

The long-term effects of quaternary ammonium compounds (QACs) on health and the environment are still being reviewed. In the meantime, there are sampling strategies for evaluating the presence of QACs on surfaces and in the air. Surface wipes include collecting a defined area with either sterile cotton gauze or a 37 mm quartz filter moistened with a 50/50 mixture of methanol and deionized water. Surface wipe samples can be transported at room temperate using a 50 mL polypropylene centrifuge or other plastic container. Air samples can be collected on a 37 mm quartz fiber filter loaded into a two- or three-piece plastic cassette at a flow rate between 1-2 L/min.

Both prescribed sampling mediums have been analyzed using gas chromatography-mass spectrometry (GC-MS) for the following quaternary ammonium chloride chemicals:

• Didecyl dimethyl ammonium chloride (CAS 7173-51-5)
• Alkyl dimethyl benzyl ammonium (CAS 68424-85-1)
• Dimethyl dioctyl ammonium chloride (CAS 5538-94-3)
• Decyldimethyloctylammonium chloride (CAS 32426-11-2)
• Alkylbenzyldimethylammonium chloride (CAS 63449-41-2)
• C₁₂-C₁₄ Alkyl(ethylbenzyl)dimethylammonium chloride (CAS 85409-23-0)
• C12-C18 Alkyldimethylbenzyl ammonium chloride (CAS 68391-01-5)
• n-Alkyl dimethyl ethylbenzyl ammonium chloride (CAS 68956-79-6)
• n-Alkyl dimethyl ethylbenzyl ammonium chloride (CAS 85409-23-0)
• n-alkyl dimethyl benzyl ammonium chloride (CAS 53516-76-0)

Currently, no agencies or organizations, including OSHA, NIOSH, and ACGIH, have recommended occupational exposure limits for the listed QACs. Despite the lack of defined exposure limits, as with any biocide, environmental application should be done with care and sensitivity to individuals’ potential acute physical reactions.

The recommended field monitoring mediums provide a means to collect environmental data for potential residential or occupational exposure assessments. For more information regarding available analytical methods for QACs, please contact your preferred commercial analytical lab to discuss prior to sampling.

Resources

Applied and Environmental Microbiology: “Benzalkonium Chlorides: Uses, Regulatory Status, and Microbial Resistance” (July 2019).

EPA: “About List N: Disinfectants for Coronavirus (COVID-19).”

Food and Drug Administration: “FDA Issues Final Rule on Safety and Effectiveness of Consumer Hand Sanitizers” (April 2019).

Food and Drug Administration: “Guidance for Industry: Temporary Policy for Preparation of Certain Alcohol-based Hand Sanitizer Products During Public Health Emergency (COVID-19)” (March 2020).

ScienceDirect: “Medical Diagnosis and Therapy” in Glaucoma, 2nd ed. (2015).