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Evaluating the Residual Value of a Chemical Disinfectant


Chemical disinfectant fogging

The global pandemic has caused a dramatic increase in the use of chemical disinfectants and unfortunately, some of these include claims of residual efficacy against viruses. Many of these claims are false, and although EPA will pursue false claims, it can take time. In the meantime, it’s up to consumers and commercial disinfectant users to educate themselves about potentially false claims. 

There is a lot of misinformation about the products used to help prevent the spread of COVID-19, and the truth is, a virucide cannot legally have a residual claim. According to the agency, “EPA has not evaluated the efficacy of any products claiming long-lasting efficacy against viruses. Therefore, there are no EPA-registered products with label claims that they are effective against viruses over the course of hours to months (i.e., “residual” or “long lasting” efficacy claims).” 

What Is Residual Efficacy?

Some disinfectant products claim to have residual efficacy, meaning that they continue to be effective for a period of time after being applied. Residual efficacy to prevent the growth of odor-causing bacteria is possible with some sanitizers, such as quaternary ammonium compounds and phenols, but this claim does not apply to virucides because the EPA has not tested for this use. It’s also worth noting that even the products that are effective against odor-causing bacteria are not allowed to make claims about the residual effects on disease-causing bacteria.

Assuming it has been approved by the EPA, any label claim that includes residual efficacy is referring to bacteria and can only be used with sanitizing agents, not disinfectants. 

What to Look for When Seeking a Solution for SARS-CoV-2

If you are responsible for selecting and purchasing disinfectant products for your facility, it’s important to understand which ones are and are not effective against viruses, including coronavirus.

Regulatory Approval 

The EPA has published its “List N: Disinfectants for Use Against SARS-CoV-2 (COVID-19),” which includes all of the approved products based on their efficacy against similar types of viruses. If you are considering a particular disinfectant for your facility, confirm that it’s on this list before you purchase. 

Product Labels

In addition to being registered with the EPA, disinfectant products also come with two objective labels that can help you get information with no marketing spin. The EPA master label and the safety data sheet (SDS) will provide you with impartial data so you can compare products without being influenced by other factors.

Cleaning and Disinfection

Many disinfectant products (bleach, for example) are less effective on surfaces that are soiled. This is why it’s so important to first clean a surface and then disinfect it. Unfortunately, people don’t always follow all of the required steps, which can lead to surfaces that are not as safe as intended. A product that also contains a detergent will clean and disinfect surfaces at the same time, saving a step and ensuring that the disinfectant will be effective, 

Ease of Application

Different types of surfaces require different approaches when it comes to disinfection. Some can be liberally soaked or sprayed, some are more delicate than others, and some have intricate textures that can harbor bacteria and viruses. Look for a flexible product that can be applied as a spray, soak, or foam. It’s also worth noting that the easier it is to use, the more likely it will be applied properly by the people doing the work. 

Low Corrosivity and Toxicity

Sensitive equipment and certain types of materials do not do well with harsh chemicals. For example, the recommended 10 percent concentration of bleach is both corrosive and irritating, which could have a negative impact on both surfaces and the people interacting with them. The health and safety of the people applying the products is also an important consideration when choosing a disinfectant for your facility. 

High Log Kill

Although it’s important to select a disinfectant that has been approved by the EPA for use against COVID-19, it’s also critical to understand that not all approved products have the same level of efficacy. Log kills are the metric used to indicate how effective a disinfectant is, with a higher log kill being better. For example, a product that kills 99.9 percent (3-log kill) of viruses will reduce by a factor of 1,000 virus particles, while one with a 6-log kill will reduce by a factor of 1,000,000 virus particles. This is perhaps the most important factor to consider when selecting a disinfectant.  

Include D7 in Your Disinfectant Search

If you are trying to determine which products to use in your facility, consider D7. With a greater than 6-log kill, this low toxicity and low corrosivity product can be safely applied in a number of ways depending on the surfaces being treated. Check out the Decon7 Product Guide for more information about our disinfectant and applicator products.