Can Oxidizers Be Used To Remove Mold?

An Investigative Report
By: Daryl Olsen

The claim that oxidizers can remove mold is a complex and confusing issue. Some manufacturers make overt claims that their oxidizer product will remove and eliminate mold. Other manufacturers make more limited claims that their product will remove mold stains but may stop short of claiming that they physically remove the mold. Some that claim to remove mold stains suggest in subtle ways that the mold has been eliminated or removed. Many oxidizers are effective bleaches. By applying a bleach, mold stains can be removed or significantly reduced.

Some oxidizers claim to “remove” mold because they are sterilants or an anti-microbial.

This example is common or central to the confusion. Does killing mold remove it? Obviously not, but has it removed any health risk of the mold? If mold spores remain, the chemicals produced by the mold also probably remain and some of the health risks associated with the mold will also remain.

These are some examples of the confusion that can arise within the industry. When professionals within the industry are not in agreement on what “mold removal” means or how it is achieved the confusion to consumers is compounded. Customers naturally wonder who they can trust and is there a correct way to remove mold.

It is because of this disagreement and confusion that I choose to study the use of oxidizers for removing mold.

Several manufacturers offer products that claim that by applying their oxidizers, that mold will be removed and the surface will be left clean. None of the industry guidelinesArecognizes this as an alternative, to physically removing the mold.

One of these products is Concrobium Mold Stain Remover manufactured by Siamons International. Claiming it “cleans moldy surfaces in a single application with no scrubbing, blasting, or vacuuming.B

Is this a new miracle method for mold removal that is able to leave surfaces clean and free of mold? This manufacturer claims that it is, but where is the proof? Without proof or endorsements from the industry guidelines, I wanted to test the product for myself to determine what it could do.

The main hypothesis I wanted to test was if Concrebium Mold Stain Remover could not only remove mold stains, could it also remove the mold itself sufficiently that the surfaces are clean and free of mold.

To test my hypothesis, we will take tape lift samples from surfaces with visual mold. We will take pictures of the surfaces to be treated. We will mix and apply the product according to the directions on the label. We will allow time for the surfaces to dry. We will take pictures and collect tape lift samples again from the same surfaces. Lastly, we will compare the before and after visual results and tape lift results. The post application tape lift samples will tell us if they are “clean and mold free”.

It is to be noted that Concrobium does not advocate porous drywall and other porous materials be saved and treated. They recommend that the product be used on semi-porous or non-porous materials. I wanted to test the effectiveness of Concrobium on a variety of surfaces. I performed tests for mold growing on several painted surfaces, wood framing and unfinished drywall.

We would like to examine the claims by the manufacturer more closely. According to the manufacturers’ product specification sheet, it claims to be a unique, non-foaming solution that quickly and easily removes the toughest mold stains on a range of surfaces, and is the ideal choice for professional mold remediators.C

“Unmatched Efficacy- high oxidation potential effectively removes mold stains from surfaces, renewing their look in a single application.”D

This product is adding more to the confusion of mold removal standards among consumers and even among mold removal personnel. This product claims to be “a mold stain remover”. The problem is, once the visual mold is gone some people make the assumption that the mold is gone. The manufacturer of this product in subtle and not so subtle ways is suggesting that the “mold” has been removed rather than just the “mold stain” was removed.

“No Harmful Chemicals- contains no chlorine or other harmful chemicals; the active ingredient is widely used in food processing. After use the product breaks down into oxygen and water. Concrobium Mold Stain Remover employs peracetic acid, a highly effective oxidizing agent for mold and bacterial stains. Upon mixing, the patented process generates peracetic acid of 2%, an effective threshold for cleaning.”E

Peracetic acid is a more effective bleaching agent than hydrogen peroxide itself. Peracetic acid is a strong oxidizing agent and a primary irritant. Exposure to peracetic acid can cause irritation to the skin, eyes and respiratory system and higher or long-term exposure can cause permanent lung damage. In addition, there have been cases of occupational asthma caused by peracetic acid.F

“Easy To Use- requires no scrubbing and no clean-up; just wet the surface and allow to dry cleans most surfaces in a single application.”G

In many of their advertisements they claim that their product “delivers world class mold cleaning without abrasive blasting. Cleans moldy surfaces in a single application with no scrubbing, blasting, or vacuuming.H

In both of these statements they are clearly claiming to clean mold affected surfaces without any physical removal, and without limiting their claims to only the mold stain.

In a spotlight article in Restoration & Remediation, Siamons International was asked “Does mold removal have to be so labor and capital-intensive?” They answered “Concrobium Mold Stain Remover, launched last year with incredible field results, removes the toughest mold staining with no toxic chemical, no scrubbing, and no clean-up.I

Their answer is specific to “mold stain removal”, but the question was about mold removal; which would suggest to anybody reading the article that they consider mold removal and mold stain removal to be the same.

Also in that article they claim “Concrobium Mold Stain Remover can be easily sprayed onto structural materials with visible mold growth to physically remove contaminants.J

Their claim here is unmistakable: “to physically remove contaminants”, they are clearly claiming that Concrobium Mold Stain Remover sprayed onto structural materials will physically remove the mold.

To carry out my testing of the product we chose two properties with heavy concentrations of mold to conduct our test. We identified surfaces to be treated, took before pictures and test samples. We applied Concrobium Mold Stain Remover to the affected areas, allowed dwell time and allowed it to dry per the label instructions, then did another round of tests and pictures. We then compared the before and after results.

In the first home, Concrobium Mold Stain Remover was used on areas labeled C1 & D1 and all surfaces in closet C and office D. Tape lift samples were taken from each of the surfaces before applying the product and again a few days after applying the product.

In the second home, Concrobium Mold Stain Remover was used on all tested areas. Tape lift samples were taken from each of the surfaces before applying the product and again a few days after applying the product.

Surface C1 showed very high levels of Aspergillus/Penicillium before application and high levels of Aspergillus/Penicillium after application.K

Pre treatment of area C1

Pre treatment of area C1

Post treatment of C1

Post treatment of C1

Surface D1 showed very high levels of Pithomyces before application and very high levels of Chaetomium after application.L

Pre treatment of D1

Pre treatment of D1

Post treatment of D1

Post treatment of D1

Surface D Framing showed high levels of Ascospores.M

Post treatment framing of D

Post treatment framing of D

In the second home, Concrobium Mold Stain Remover was used on all areas tested. Which were labeled A, B, C, and D.

Surface A showed modest levels of Aspergillus/Penicillium and very high levels of Chaetomium before application and very high levels of Chaetomium after application.N

Pre treatment of A

Pre treatment of A

Post treatment of A

Post treatment of A

Surface B showed very high levels of Alternaria before application and very high levels of unidentified fungi after application.O

Pre treatment of B

Pre treatment of B

Post treatment of B

Post treatment of B

Surface C showed very high levels of Stachybotrys before application and modest levels of Aspergillus/Penicillium, Stachybotrys, and unidentified fungi after application.P

Pre treatment of C

Pre treatment of C

Post treatment of C

Post treatment of C

Surface D showed very high levels of Aspergillus/Penicillium before application and very high levels of Aspergillus/Penicillium after application.Q

Pre treatment of D

Pre treatment of D

Post treatment of D

Post treatment of D

The product made significant improvements in removing the visual mold or the mold stains. Some of the mold rinsed or melted away which may explain why some areas tested high for different kinds of mold before and after application. Regardless of appearance all surfaces tested high or very high for mold. The labels on the product are careful to say that they remove “mold stains”. The product is not an alternative for physical removal of the mold.

This was a limited study testing one oxidizer product on a handful of surfaces. This product was selected because it is one of the more visible and heavily advertised products in the category.

Concrobium did not meet the standard of care for physical removal. Mold affected surfaces were not clean and free of mold after using the product. There are many other competing products. There are also products that claim to leave the area or an entire home mold free by fogging an oxidizer into the area.

Probably the greatest lesson learned is that when considering an alternative practice that does not incorporate physical removal of the mold, is to be skeptical. Alternative methods may be attractive because they may be much faster and cheaper, but we should be careful to make sure that they deliver satisfactory results. If there is any doubt about the results, test surfaces before and after to verify.

When would a customer want to remove a mold stain with no concern for removing the mold? The reason that people want to remove mold is because of the potential health concerns. If mold stain removers do not meet the goal of customers, why is there a market for them at all?

What does it mean for the mold removal industry? I believe there is a lot of confusion between mold stain removal and mold removal. Customers and contractors both would like a removal solution that is faster, cheaper, cleaner and less labor intensive, but we should be careful that we actually deliver results.

I urge mold industry manufactures and contractors to be accurate and transparent about what is provided, and what the results are with adequate verification.

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