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Microban - Do You Need to Use It?

Microban®

Introduction

Microban is possibly the most common antimicrobial product professional mold remediators use. It’s not because it’s the most effective. It simply has the largest market share. According to the manufacturer’s website, Microban formulations are in thousands of substrates worldwide including apparel, footwear, textiles, air filters, building materials, and health care products.

For purposes of this blog, I’m going to reference the product Safety Safety Data Sheet (SDS) for a formulation used by a professional mold remediation company I’ve had experience with: Microban Disinfectant Cleaner Concentrate Mint. (https://www.legendbrands.com/media/uu2ckeuc/microban-dcc-mint-aghs-published-sds-aug-24-2016.pdf).

According to the data sheet, ingredients include the following:

Based on California Proposition 65, the product additionally contains:

  • Formaldehyde
  • Toluene
  • Propylene Oxide
  • N-Nitrosodimethylamine
  • Acetaldehyde

Neither the safety data sheet nor the California Proposition 65 information list the ingredients in the fragrance. Similar products sold by Microban contain fragrance.

In one investigation I sent a sample of the Microban the remediation company used to the lab for analysis for VOCs (volatile organic compounds), ie chemicals that become airborne at room temperature.  The results show the Isopropanol and Ethylacetate.  Isopropanol is a widely used as a disinfectant and antiseptic (rubbing alcohol). Ethylacetate is not an antimicrobial like isopropanol or thymol (Benefect). It works mainly as a solvent. Ethyl acetate is a main ingredient in nail polish removers.

Ethyl acetate is not designed to kill mold. Using it indoors adds more chemicals into the air — the opposite of creating a healthy living space. This is why when Benefect came on the market, mold inspectors and remediation companies were quick to recommend Benefect to clients who wanted something “safer” than Microban. The thought at that time was that since the active ingredient in Benefect is thyme oil, it must be more natural and therefore “healthy”. They failed to consider if  natural means “healthy” and why in general, disinfectants and antimicrobials are not required to remove mold.
 

Applications

Microban is EPA registered for application that include water damage restoration, sewage backups, removal of carcasses, toilet overflow situations, and more. It is EPA registered for both spray and cold fogging applications. 

Microban comes in a bottle as a ready-to-use liquid to be sprayed on surfaces. The general application instructions are as follows: Surfaces and objects must be cleaned of gross filth with suitable detergent before treatment. Spray surfaces and articles until thoroughly wet. Use enough so that treated surfaces and objects remain wet for at least ten minutes.

For fogging, it says to use appropriate spraying equipment, protective clothing, gloves and a respirator. Heavily treated spaces should be adequately ventilated and not reentered for at least one hour after treatment. If applying by sprayer, apply to non-porous surfaces at a rate of 1,500 square feet per gallon; 400 square feet per gallon for porous. Spray until moist.

 

My Opinion & Concerns

In regard to creating a healthier living space -  I was taught the principle “Remove the hazard; Don’t introduce anything new.” The application of such products violates that principle.

A main concern of mine is the residual ammonium quaternary. The residuals left behind include salts, which may serve to aid in preventing future growth of microbes as the manufacture claims.

Quats are lung irritants and may contribute to asthma and breathing problems. https://womensvoices.org/2018/05/08/what-are-quats-and-why-are-they-on-our-list/.

Quats are generally not considered “safe.” 

There is no “safe” level of ammonium quaternary.

Remediators tend to be overzealous about how much they spray. They are generally not knowledgeable about the information in safety data sheets nor the application instructions.

Some remediators think that since this is an “alternative antimicrobial” it may be used to “treat” mold, i.e., kill mold. As such, they often seem to believe that it’s not as important to remove all of the mold.

 

How It Works

The likely active ingredients (those that disinfect) are quaternary ammonium compounds, also know as Quats, and the alcohol.

Bacteria and Viruses: Quats are effective at killing bacteria and viruses. It is generally believed the predominant mode of action is disruption of the cell membrane. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7111226/#sec0005title Quats work to kill bacteria and viruses by breaking open the cell membranes of bacteria. Breaking the membrane causes cell death.

For this process to be effective, the organisms must come in contact with the product for a period of time known as “contact time”. This is typically a few minutes. (Microban specifies at least 10 minutes). The significance of this is that while spraying a hard surface may allow the organisms on the surface to come in contact with a product for an adequate amount of time, not all the organism in a porous material may come in contact with the treatment.

The application might sound good and wonderful when used to kill virus and general types of bacteria. In buildings with water damage and mold, predominant type of bacteria are gram-negative. The toxin people have a physical reaction to is contained in the cell wall of the organism. Exposure comes from inhaling fragments of dead organisms - not infection. It’s unlikely the dead stuff is physically cleaned up and physically removed by a mold remediation company. Therefore, there may be a greater potential for exposure to these harmful particles if a treatment is used, compared to if a remediation company simply removed wet and water damaged building materials and discard them.

Fungi: It is not well understood how quarts work to kill mold (fungi). Previous studies attributed the anti-fungal mechanism of qutas to electrostatic interaction with the cell membrane that results in cell lysis (disintegration of the cells) similar to what happens for bacteria. Recent studies instead suggest the anti-fungal activities may involve the impediment of the formation of hyphae (mold’s roots). This would be similar to how phenols, present in essential oils such as Thyme and in the product Benefit (see blog link), work.

In layperson terms — the application kills the roots of the mold, stoping mold that receives the treatment from growing further. Similar to the phenol treatment (that of Thyme oil in the product known as Benefect for example), spraying the product on mold does not remove the hyphae, spores and other allergens and potential toxigenic matter that may be present.

 

Is this product more effective than using plain soap and water?
In my opinion - no. The chemistry and ingredients of the surfactants in Microban do not appear to allow it to perform better at cleaning than plain soap and water. If this were the case we’d be using Microban to wash dishes.

 

Was it just the odor?

It has been the unfortunate case that some homeowners could not tolerate living in their home after Microban was applied. It’s not certain why. A likely and common reason is the mold remediator did not remove all of the mold. My experience with remediators is that when they spray or use products other than soap and water, they don’t clean as well.

I have seen cases where the mold was all removed, and individuals still could not tolerate being in their home after the product was applied. I used to think the odor was the reason. Primarily, I thought the odor was due to the alcohol. It may be a combination of the alcohol, fragrance, and other ingredients.

Although an odor would seem the likely reason for complaints; it’s not certain the odor was the cause or sole cause for a physical response. If you read my blog post on the disinfectant, Benefect, using antimicrobial results in competing organisms, those not affected by a product, to flourish. This is why the standard on professional mold remediation, the S520, recommends against the use of antimicrobials in general.

In the case of Microban, I think something else may be a factor for the complaints. Ethanol is a common ingredient in fragrances, house-hold cleaning products and personal care products, It’s a common indoor pollutant, suggesting something else is a contributing factor. Perhaps the quat (the salt residual) is the factor.

 

Conclusion

We know that mold on hard and semi-pours surfaces can effectively be removed by brushing and/or cleaning with soap and water (dish soap). In my opinion using a product other than soap and water does not result in a more effective job at removing mold. Regardless of how safe other products may appear, there is some inherent risk in using them. Why take chances?

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