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: Microban Disinfectant Cleaner Concentrate Mint. According to the data sheet, ingredients include the following:

Quaternary ammonium compounds, di-C8-10-alkyldimethyl, chloride

Ammonium chloride compounds

Tertrasodium EDTA (Commonly used as a chelating agent, making hard water become soft, allowing surfactants to do their job.)

Additionally, based on California Proposition 65, the product contains:

Neither the safety data sheet nor the California Proposition 65 information list the ingredients in the fragrance. A similar product sold by Microban does as follows:

Applications

Microban is EPA registered for applications that include water damage restoration and sewage backups. It is registered for spray and fogging applications. 

the Microban used by most remediators 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, 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 and Concerns

In regard to creating a healthier living space, I was taught the principle “Remove the hazard and don’t introduce anything new.” The application of such products violates the principle. A main concern is the quat residual. The residuals left behind include salts. Quats are lung irritants and can contribute to asthma and breathing problems. Quats are generally not considered “safe.” There is no “safe” level.

Remediators tend to be overzealous about how much of it they spray. They are generally not knowledgeable about information in the safety data sheets or the application instructions. Some think since this is an antimicrobial it may be used to treat mold, i.e., kill it, and therefore it’s not as important to remove all of the mold.

How does it work?

The likely active ingredients (those that disinfect) are quaternary ammonium compounds, also know as Quats, and the alcohol. Quats are effective at killing bacteria and viruses. It is generally believed the predominant mode of action is disruption of the cell membrane. Quats work to kill bacteria and viruses by breaking open the cell membranes of bacteria. Breaking the membrane causes cell death. 

For the 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. While spraying a hard surface may allow organisms on the surface to come in contact with a product for an adequate amount of time, not all the organisms 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, the predominant type of bacteria are gram-negative. The toxin people have a physical reaction to is contained in the cell wall of the organisms. Exposure comes form inhaling fragments of the dead organism, not infection. It’s unlikely the dead stuff is physically cleaned up and removed by the mold remediation company. Therefore, there may be a greater potential for exposure to harmful particles if a treatment is used, compared to if the remediation company simply removed 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, however, 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 Benefet work (see my blog on Benefcet).

In layperson terms — the application kills the roots of the mold, stoping mold that receives the treatment from growing further. Similar to a phenol treatment, spraying the product on mold would not remove the hyphae, spores and other allergens and potential toxigenic matter present.

Is the product more effective than soap and water?

I doubt the chemistry and ingredients of the surfactants in Microban allow it to perform better than soap and water. If this were the case we’d be using Microban to wash our dishes.

Was it just the odor?

It has been the unfortunate case that some homeowners cannot tolerate living in their home after Microban is applied. It’s not certain why. A likely and common reason is that 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 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, but it seems to 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 an antimicrobial results in competing organisms, those not effected 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. 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 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 risk inherent in using them.