COVID-19 Disinfectant Q&A

Question 1: Is your COVID-19 Disinfectant “EPA-Approved”?

The phrase you are looking for is “EPA-registered”. The EPA evaluates manufacturer claims and, if validated, assigns a unique registration number that appears on “List N”, which is currently being updated by the agency approximately each week. That registration number must appear on the label of every container of the product sold in the U.S., including those marketed under other names. Insist on seeing that number. Otherwise, the registration claim is suspect.

Question 2:  What if the disinfectant I want to use is not on EPA List N?

Many products are marketed under a variety of names that you will not find on List N. Use the EPA registration number (should be on the product label) to search the list. If registered, it will show up no matter the brand or marketing name. Be skeptical of materials that you have not verified. In the last few weeks, more than half of those I have reviewed are not on List N despite vendor claims of being EPA-registered or approved. Most of those turn out to EPA-registered for something (e.g., disease-causing bacteria or algae and mold), but not SARS-CoV-2 (the cause of COVID-19). Some are not registered at all. Remember, if not on EPA List N the product is not legal in the United States for use against SARS-CoV-2. When a salesperson claims they are “expecting EPA approval any day” or “we have the same or similar ingredients as those registered products”, just say no and find a vendor that uses products already tested and verified by the EPA. There are many from which to choose, so there is no reason to do it wrong and spend a lot of money for something that may not work and risk infecting your returning workers.

Question 3: Does it matter how I apply the disinfectant?

Absolutely it matters. A large part of the EPA registration process is to review the exact conditions and manner in which the product is claimed to work against the virus. For example, the approval may restrict application to hard, non-porous surfaces such as floors, doors and desktops. These products would not be allowed for use on porous surfaces such as carpet or drapes since they have not been proven to penetrate the porous surface, make contact with the virus and kill it. Products such as vaporized hydrogen peroxide require a minimum concentration of peroxide in the airspace for a specific time (minutes to hours), which must be verified by air monitoring. That cannot be achieved by simply walking around with a hand-held sprayer. By federal law, the user must apply the material exactly as approved or it is considered a violation of the registration for the very simple reason that it may not work like it was supposed to work, and the area may not actually be disinfected.

Question 4: What is this word “efficacy” I keep hearing, and why do I care?

Efficacy is the ability to produce a desired or intended result. In simple terms, “How well does this stuff work?” The EPA evaluates manufacturer efficacy claims to determine whether the product does what it is supposed to do when applied as intended. Part of that evaluation is being very specific as to how to apply the material, how long to leave it on (contact time in minutes), whether the surface to be disinfected must be free of dirt or other contamination (most often yes), whether the product is dilutable or can be applied as is (ready to use / RTU) and settings in which it may be used (healthcare, institutional or residential). If the product performs as claimed, all conditions of use follow onto the EPA product label. If that label dictates spray and wait 15 minutes, then it must be at least 15 minutes. If the label states do not dilute, then do not mix with water “to make it spray better”. In the case of hydrogen peroxide fogging, minimum contact time may be 30 minutes at 200 ppm as validated and documented through air monitoring. Failure to follow label instructions not only violates federal law, but seriously threatens the efficacy of the disinfectant, quite possibly resulting in a work space not free of virus and a costly false sense of security for returning employees. With pressure to “restart the economy” and bring workers back into suspect environments, it is more important than ever to be certain about your disinfection efforts.

Question 5: Beware the Fog

One of the most egregious abuses of disinfection methods I am seeing is the incorrect use of hydrogen peroxide (HP) fogging. As of the April 16, 2020 List N update, there is only one registration for HP application by fog and one for vapor. The requirements for both are quite specific, so if your vendor is using HP fog/vapor, but not doing it correctly (specific hydrogen peroxide concentrations and hold times, specialized equipment, air monitoring etc.) then you are spending a lot of money on something that violates all applicable regulations and does not work. The giveaway is seeing your decon “expert” walk around waving a hand-held fog unit like a magic wand and clearing the space in minutes. The advantages for scam artists are many: the “cool factor” of HP fogging; its near-mythical virus-killing reputation; many client’s relative lack of understanding of the science (and the law); and the lure of disinfecting large areas quickly with no chemical residue, odor or negative effects on equipment. Awesome if it worked that way, but it does not. When a vendor proposes fog or vapor, check the EPA product registration, the equipment to be used, the source of training for the technicians doing the work and how they intend to achieve and maintain the required concentration and contact time parameters along with meeting all other label requirements. Verify everything, and refuse any service that does not comply with the letter of the law. Otherwise, the virus will be waiting for your employees when they come back into their nice, “clean” workspace.


For more information or to comment on this article, please contact:

Scott Harris, PhD, Senior Project Manager  | CONTACT
GDS Associates, Inc. – Austin, TX
512-717-8053 or