Myths and truths about mold

The dangers of mold cannot be underestimated, but sometimes there are many myths surrounding mold that mislead people. Let's find out what's true about mold and what's false.

Our long experience with people who have encountered mold infestation shows that there are many myths about mold that have nothing to do with reality. Below you will find a listing of the most common myths (left column) and their debunking (right).

Myths about mold and their debunking

  • “Mold is not a health hazard, it’s purely a cosmetic defect.”
  • “The most that can be harmful from mold is a mild runny nose.”
  • “Mold causes cancer.”
  • “Only black mold is dangerous.”

Very often representatives of housing services lull the vigilance of tenants affected by mold, assuring them that mold is not dangerous to health. By no means believe such irresponsible statements!

Molds belong to groups III-IV of pathogenic microorganisms. Molds are harmful to health by inhalation, in contact with the skin. It can cause allergic diseases (the whole spectrum – bronchitis, rhinitis, dermatitis, asthma…), and deep mycosis (damage by mold fungi to internal organs).

There is no scientific evidence that exposure to mold fungi has anything to do with the occurrence of cancer. The connection between these factors can only be made in a very indirect way – via the effect on the immune system.

Hypersensitivity to mold fungi (so-called mycogenic sensitization) can in some cases be detected by serological tests – a blood test for the presence of antibodies to mold allergens.

However, some people do not develop this sensitization despite years of living in an infected room. Many species of mold fungi can develop in rooms that have been subjected to leaks or flooding, and they have different properties. Among them there are species that are more or less harmful to human health, but all of them are harmful enough to immediately sound the alarm when they appear in the apartment.

Living in contaminated rooms is not allowed, especially for children, the elderly and those with serious illnesses.

“There shouldn’t be any spores of mold in the air,” or “You need to turn on an ultraviolet lamp in the apartment often and then mold won’t grow.”

The original source of mold spores is the surrounding natural air environment, in which they are normally present in insignificant background amounts.

It is not possible, and not necessary, to completely get rid of the presence of mold spores in our environment. However, it should be kept in mind that under favorable conditions (increased humidity), the few spores of mold fungi begin to spread, the substrate for them is a wide range of materials, including building and finishing materials, fabrics, wood, some polymers, etc.

The use of UV lamps is quite dangerous to human health because it leads to the formation of free radicals in the air.

The use of UV lamps is reasonable for medical facilities, but not for continuous use in apartments.

As mentioned above, trying to get rid of single mold spores makes no sense (they will appear after the first airing, which, incidentally, should be done after UV irradiation). In addition, UV irradiation is more effective against bacteria and viruses, while many fungal spores have thick cell walls that reliably protect them from the killing effects of UV radiation.

It is much better to maintain a normal microclimate in the apartment and avoid overwatering materials and the accumulation of condensation on surfaces.

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“You cannot get rid of mold once it has started”

To remove (destroy) mold is quite possible, there is nothing supernatural in this phenomenon. You just need to get competent recommendations from specialists-mycologists on the amount of removal of affected materials and on antiseptic agents that should be used to treat the affected surfaces, or use the services of professionals to remove mold (with a guarantee).

However, keep in mind that not all antifungal agents widely available in construction stores are effective. In our experience, only 2-3 means really work, reliably removing mold and protecting against its reappearance.

Be warned, however, that there is no one product that will protect your home from mold forever, no matter what the emergency. Antiseptics, even the best ones, decompose over time, and they are also washed out by water from major leaks. In addition, it is illegal to use some particularly strong products for residential environments because they are toxic.

“If you wall up the mold well under the finishing materials, it won’t do any harm and it won’t come out.”

This is absolutely wrong, because due to their microscopic size mold spores easily penetrate through the smallest gaps, infecting the air in the apartment and creating an allergenic microclimate. It is impossible to wall up mold completely. Once walled up, mold continues to grow under the finishing materials as in an incubator, and sooner or later will still sprout out.

Mold fungi decompose or destroy all organic materials as well as glass, metal, plastics, ceramics, concrete and bricks. The development of mold under and in the thickness of finishing materials results in a characteristic musty odor caused by the production of volatile organic substances (aldehydes, ketones, etc.), many of which are themselves harmful to human health.

“Molds can’t appear in a week.”

Molds grow very quickly, especially if they have enough moisture. In case of emergencies – leaks, floods, firefighting – mold can appear on the walls in 5-7 days if the rooms are not dried in time. The use of modern finishing materials (plasterboard structures, plastic, vinyl, etc.) makes it much more difficult for rooms to dry quickly. Under flooring and wall coverings, because of this, a massive mold infestation develops almost 100% of the time within 1 to 3 weeks of the accident.

“If there’s no mold smell, there’s no mold itself.”

This is an absolutely incorrect opinion, cultivated by some representatives of housing and maintenance services to lull the vigilance of tenants affected by accidents related to flooding of premises. Not always the development of mold is accompanied by the appearance of a characteristic smell (it depends on the species of mold fungi, the degree and duration of the lesion).

“After treatment with antiseptic, mold residues are not dangerous and can not be removed.”

This is absolutely incorrect opinion, since mold spores retain allergenic and toxigenic properties even after antiseptic treatment. The allergenicity of fungi has nothing to do with their viability, but is related to the protein components that make up the cell wall of fungi.

Therefore, it usually requires complete removal of mold-affected building and finishing materials (drywall, wallpaper, paint, putty, plaster layer in the foci of infestation).

“Copper sulfate is the best remedy for mold!”

Copper sulfate is not even yesterday, but the day before yesterday in anti-mold treatment. It is a toxic compound of heavy metal – copper, in elevated quantities dangerous to human health (and it is in such quantities that it must be used to achieve an anti-mold effect). There are modern, effective and safe remedies and methods for fighting mold.

“If the apartment was flooded a year ago, mold that appeared a week ago is related to that flood.”

If the apartment was quickly dried out after the flood, and there are no signs of mold infestation for 2-3 months, the unexpected appearance of mold is likely due to other causes. As stated above, mold develops quickly and only on damp materials.

“After a leak, we had mold crawl in from the neighbors!”

If there has been a major flood affecting neighboring apartments or apartments on several floors, and mold has begun to appear in all the apartments (perhaps not simultaneously), it is likely to appear in each apartment independently, from its own, “internal” sources, influenced by moisture from soaked walls, floors, ceilings.

Of course, if there are heavily infested dwellings near your apartment for a long time (months or years), you can’t rule out the possibility of mold sprouting from them to you. However, in random accidents, it’s wrong to blame the neighbors. Mold spores are always around us, and once they get on damp materials, they will germinate and develop.


I enjoy acquiring knowledge and sharing it. I am a long-time health advisor and blogger for over 12 years. Understanding the dangers of black mold to people, I felt it necessary to share with readers the basics of fighting and preventing black mold in homes and other living spaces.

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