Published by Houlton Medical Office Cleaning | (866) 958-8773
EPA List N is the Environmental Protection Agency's registry of disinfectants that meet the criteria for use against SARS-CoV-2, the virus that causes COVID-19. The list was established in 2020 and is maintained as an ongoing reference for healthcare facilities, cleaning contractors, and the public. Understanding how to use it — and specifically what "dwell time" means — is the difference between a surface that has been disinfected and one that has only been wiped.
List N products have been tested and confirmed by the EPA to be effective against SARS-CoV-2 and, by extension, against harder-to-kill pathogens on a tiered basis. A product appearing on List N is not automatically appropriate for every surface in a medical facility. The list includes products with different formulations, different target surfaces, and different dwell time requirements. Using a product not rated for porous surfaces on porous upholstery may not produce the intended result regardless of List N status.
The EPA maintains the list at epa.gov/pesticide-registration/list-n-disinfectants-use-against-sars-cov-2. Products are identified by their EPA Registration Number, which appears on the product label.
Every disinfectant on List N — and every disinfectant used in clinical settings — has a labeled dwell time. This is the amount of time the product must remain visibly wet on the surface to achieve the disinfection efficacy stated on the label. Dwell times range from 30 seconds to 10 minutes depending on the product and the target pathogen.
A surface that is sprayed and immediately wiped dry has not been disinfected. The product has been removed before it had time to work. This is the single most common disinfection failure in commercial cleaning operations, and it is invisible — the surface looks clean whether it was disinfected correctly or not.
In a clinical setting, incorrect dwell time application is not a cosmetic failure. It is an infection control failure.
Some List N products that are highly effective at killing pathogens are also aggressive toward certain materials. Bleach-based disinfectants can discolor upholstery and corrode metal fixtures over time. Quaternary ammonium compounds are gentler on surfaces but may have longer dwell times. Hydrogen peroxide-based products work quickly on most hard surfaces but require different handling.
A cleaning contractor who uses a single product for every surface type — exam table upholstery, metal fixtures, vinyl flooring, countertops, electronic equipment housings — is either ignoring surface compatibility requirements or hoping you won't notice when finishes degrade prematurely.
These are reasonable questions. A contractor who treats them as unreasonable is telling you something important about their operation.