For nearly as long as humans have known about black mold, they have worried about its potential effects. During the early 1900s, people began to claim that black mold was extremely toxic and could cause many health issues. Anecdotal reports and studies indicated black mold could lead to everything from congestion to cancer. However, in recent years, experts have raised some doubts surrounding black mold and its presumed effects.

Types of Black Mold

One of the main sources of confusion concerning black mold is that people believe it is a single type of mold. In reality, there are many black molds, with the two most common being Stachybotrys chartarum and Aspergillus niger. Both types grow in unique environments, with the former found in cellulose-rich building materials, though it can sometimes appear in soil or grain. A. niger grows primarily on fruits, vegetables, and soil. Because it can sometimes appear in indoor environments, people often confuse it for other types of black mold.

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Some molds are capable of causing illness. Usually, this is due to mycotoxins. A single mold species can produce a variety of these compounds. In humans, mycotoxins can cause mycotoxicosis, which inhibits lung functions and prevents protein synthesis. Factors such as vitamin deficiencies, alcohol use, and caloric deprivation can also compound these symptoms. Unfortunately, there is a notable lack of research on mycotoxin's effects.

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A. niger Claims

Among the most common claims about A. niger is that it can cause a serious lung disease — aspergillosis. In reality, this is extremely rare, and it is other forms of the Aspergillus fungus that cause this illness. The most common condition resulting from regular exposure to A. niger is otomycosis, which is a fungal ear infection. It can cause pain and temporary hearing loss.

aspergillus niger petri dish Sinhyu / Getty Images


S. chartarum Claims

First discovered in 1837, S. chartarum has been at the center of many medical claims. It grows in cellulose-rich building materials in extremely humid or wet environments. Some researchers claim they can link the mold to sick building syndrome, where multiple people residing or working in the same building feel unwell for seemingly no reason. Other sources have asserted that the mold can lead to idiopathic pulmonary hemorrhages or bleeding in the lungs in both animals and humans. Some of the earliest stories of the effects of black mold began at the start of the 1900s when many farm animals in Russia died due to black mold in their feed.

black mold chartarum Fevziie Ryman / Getty Images



Despite the many claims concerning black mold, there is very little supporting evidence for most of them. In terms of A. niger, some claim the mold can produce dangerous mycotoxins called ochratoxins, while others argue that this is due to the misidentification of the fungus. Interestingly, A. niger has many useful industrial purposes, such as in the production of high-fructose corn syrup. Other types of black mold, such as S. chartarum, lack significant evidence proving any adverse effects. Scientific literature expresses no firm link between it and sick building syndrome, and studies proving the negative effects of the mold are few and far between. Most studies identify that illness requires exposure to unusually high levels of S. chartarum. Additionally, not all strains produce mycotoxins and those that can do sometimes lose their ability to produce such toxins over time.

researcher study controversy poba / Getty Images


Possible Symptoms

If a person does have mycotoxicosis or another mold-related illness, they will likely begin to exhibit symptoms such as wheezing, coughing, nose stuffiness, and itchy skin or eyes. People with allergies or asthma will likely have worse symptoms, such as headaches, exhaustion, coughing, fever, and breathing difficulties. Experts claim that long-term mold exposure can lead to hair loss, anxiety, numbness, asthma, cystic fibrosis, and many other serious conditions.

coughing respiratory issues Moyo Studio / Getty Images



There are many possible ways for a person to become exposed to black mold. A. niger is usually consumed. Onions are particularly susceptible to this mold, as are peanuts and grapes. Though rare, there have been cases of people inhaling the fungus after exploring Egyptian tombs. Generally, when people are worried about exposure to black mold, they are concerned about S. chartarum, which tends to grow on building materials such as gypsum or wallpaper in areas of high humidity or after water damage. Despite popular belief, S. chartarum only releases its spores following a mechanical disturbance.

black mold onion witoon214 / Getty Images


Mold Allergies

What many people believe is an illness from exposure to black mold may be a mold allergy. Essentially, the body overreacts after breathing in mold spores, causing a serious allergic reaction. While the symptoms can vary, they usually resemble those of any other respiratory allergy. This typically includes sneezing, runny nose, watery eyes, dry skin, and itchy eyes. Some studies note links between mold allergies and asthma, and mold exposure may restrict breathing.

mold allergy reaction PeopleImages / Getty Images


Visiting a Doctor for Mold Allergy

Currently, there are no tests that can link molds such as S. chartarum to issues like pulmonary hemorrhages or other health symptoms. Despite this, individuals who suspect they have a mold-related ailment should immediately visit a physician. Doctors will perform blood or skin prick tests to identify possible allergies or reactions to mold. The Centers for Disease Control and Prevention recommend individuals remove molds they find in their homes. They also state that it is not necessary to identify which mold is present. All molds represent a potential risk.

doctor patient mold respiratory MesquitaFMS / Getty Images


Protecting Against Black Mold

Regardless of the lack of research, there is still the possibility that black mold is dangerous. A person hoping to protect themselves should regularly check their home for black mold. Individuals who live in areas of high humidity may benefit from a dehumidifier. Additionally, areas with water damage are particularly prone to S. chartarum. Sections of buildings with poor ventilation are also susceptible.

water damage humidity mold MediaProduction / Getty Images


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