Why Fogging For Mold is a Bad Idea

May 23, 2019

During the week, our company received two nearly simultaneous calls about situations involving mold remediation where fogging was used as the primary method of removal. One of these prospective clients mentioned that the fogging was ineffective and there was still residual fungal growth present. The other noted that their spouse developed a palsy after the chemical was used and can no longer reside in the residence. In this blog, we will discuss why fogging is not recommended for routine mold remediation projects.

What is Fogging?

Fogging refers to the method of using an antimicrobial pesticide in an aerosolized form in order to kill mold present in a property. While mold remediation isn’t as regulated as other forms of environmental cleanup such as asbestos or lead abatement, there are organizations who set industry standards and guidelines. The Institute of Inspection Cleaning and Restoration Certification (IICRC) produces and maintains a consensus-based standard and the Environmental Protection Agency (EPA) wrote a remediation guideline. The IICRC states that vapor based antimicrobials have not been shown to be able to effectively and safely be used for remediation. The top issues with using the chemicals in this manner are the delivery of the antimicrobial, efficiency, and the potential toxicity of the compounds being utilized. The EPA does not recommend using this method unless the product is registered for that specific purpose.

When Can Fogging be Used?

The EPA defines antimicrobials as chemicals that are used to suppress or destroy microorganisms. These materials are registered and regulated by the EPA’s Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and while not a federal requirement, some states even require licenses for those who apply them. There are also other international organizations such as the European Union that regulate the use of these antimicrobials.

These compounds should only be used for their registered purpose and improper use can affect or harm humans and also pets and wildlife. The product registration describes when the product should be used, what surfaces are allowed, if there are any location restrictions, the proper PPE (Personal Protective Equipment), and conditions the product should be applied in. The chemicals released from antimicrobial products can cause a wide range of health effects depending on the compounds present and the amount of ventilation in the work area.

How then should I kill the mold?

The attraction to fogging chemicals for mold remediation is that the aerosolized antimicrobial can kill mold in a property without having to physically go to each area and remove the fungal growth. Many companies state how their products are effective at killing the mold. While these statements may be truthful to an extent, it doesn’t actually solve the problem. While killing the mold would stop it from propagating, killing it does not take away their allergenic or toxigenic properties which will still be left around after the products have been used. The IICRC recommends that fungal growth be physically removed instead of being simply killed with an antimicrobial product. When mold with its allergenic proteins is in the dumpster outside, it doesn’t really matter if it is dead or alive.


In conclusion, fogging may be able to “kill” mold throughout a property, but it may lead to other unintended consequences. Antimicrobial fogging should only be used in the manner that its EPA registration requires. In fact, it is a violation of federal law to deviate from the labelled instructions! Improper usage may lead to indoor air quality concerns related to the pesticide compounds present in the products. Also, killing the mold does not constitute proper remediation, as the mold growth must be physically removed as killing it may leave behind spores that cause allergic or toxigenic responses.

If you have a remediation contractor suggesting fogging, consider hiring Indoor Science to write out a remediation plan that follows the industry standards and guidelines.  To learn about other common problems we see in remediation, here is another great article on common problems with remediation.