Since the commencemnt of COVID19 cleaning in March 2020, TV News and advertisments have displayed Covid 19 Cleaners racing around with hazmat gear using fogging machines to fog chemicals into the air and onto surfaces. No doubt, it does have the Hollywood cool factor. It has been shown in trams, work areas, cafes, and the list goes on. Yet, there is some unanswered questions over the effectiveness, and health and safety of this practice.
Aftermath, a company located in the United States, wrote an article on this topic. They referenced that the CDC does not list fogging as preferred method of disinfecting. Furthermore, they state that
“The approved list of cleaners, also known as the EPA “List N” is believed to be the most effective at eradicating the virus that causes COVID-19.
For example, by wiping the surface, the friction caused by the application of the disinfectant with towels ensures maximum contact with the virus, which will lead to the greatest risk reduction.’
And later state,
“Simply “fogging” an area with a disinfectant does not meet EPA-registered label requirements without proper pre-cleaning and may be a violation of federal law. More importantly, improper application of the disinfectant can lead to a false sense of security, an increase in health hazards and not be effective at reducing the risk of the spread of COVID-19.”
However, this is not America and we have different governing bodies, such as Work Safe Australia. Work Safe are here to guide and ensure that anyone who owns a business is making sure that they are operating in a safe manner, and when you look at Australia’s statistics for work place injuries, I would have to say they are doing a very good job.
On the subject of fogging for disinfection, Work Safe Australia states,
“Disinfectant fogging (sometimes called disinfectant fumigation) is a chemical application method where very fine droplets of disinfectant are sprayed throughout a room in a fog. The disinfectant has to reach a certain concentration for a certain length of time to be effective.
Disinfectant fogging is not recommended for general use against COVID-19 and can introduce new work health and safety risks. Physically cleaning surfaces with detergent and warm water, followed by disinfecting with liquid disinfectant, is the best approach. If you are looking for a faster or easier method, consider a combined (2-in-1) cleaning and disinfecting agent.”
There are some important points here. The only time a disinfectant does its job is when it has been in contact for the required time. Therefore, in relation to fogging, depending on the disinfectant being used, the product would require misting long enough to keep surfaces wet from between 1 minute, all the way up to 10 minutes. That could be a lot of fog.
Dr Karen Middleton of Clean Room Technology, a leading international publication for clean room operators and contamination control specialists, says under typical conditions, fogging needs to be carried out for a minimum of 15–30min to enable the fog to disperse and the chemical action to occur. Importantly, in this article she is referring to inbuilt permanent systems, or placed mobile units that are enough to cover the area at the right fog density and chemical concentration to get the job done (See image). She is not referring to handheld fogging equipment.
Trying to fog at this density in a large warehouse in unrealistic.
FM Contract Solutions from Western Australia stated back in March:
Some suppliers and cleaning contractors are advising their clients to use environmental fogging to disinfect office environments against COVID–19. As of 19 March 2020, there is no advice published by any public health department that indicates that environmental fogging is an acceptable disinfection technique for COVID-19.
However, Decon Solutions Australia understands that as of August 2020 the EPA in America has a few products listed that have been tested against COVID19, and have misting, or Fog as a delivery method. These are in the minority.
How do we know that the product is being applied as prescribed by the manufacturer? One way might be ATP testing of areas that have been treated, or better still SARS-CoV (E-gene) swab tests, although these do take a turnaround of 48hrs to get results. I guess, it is up to each client to do their research. Please feel free to call Decon Solutions Australia if you are looking for advice.
Until Work Safe Australia approves this method of contamination control, Decon Solutions Australia will only offer it as an option, and will discourage its use. This is due to the lack of evidence that it produces an acceptable outcome, and that it is cost prohibitive for many companies. Our approach will remain inline with Work Safe Australia and the CDC guidelines.
We would like to hear from anyone who has independent scientific research to show that handheld fogging results in acceptable COVID19 decontamination outcomes.