How to Identify Black Mold

Co-authored by Susan Stocker

Last Updated: August 20, 2024 References

Molds are commonly found in nature and help to break down the nutrients in soil. Inside, molds are potentially hazardous to your health. One common mold is stachybotrys atra, or black mold. While research on the effects of black mold remains somewhat limited, some existing research shows that inhaled mold, in general, can negatively affect conditions like asthma, particularly for individuals with mold allergy.^{[1]
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Research source} Black mold is commonly thought to be toxic when ingested or inhaled; however, it is no more dangerous than other types of mold. If you notice any signs mold, it is not necessary to identify the species, but if you do want to identify the mold, there are a few ways to go about it. First, do a sweep of your building to look in all mold prone areas to find any mold. Next, have a professional inspection done to identify black mold.

Method 1

Method 1 of 3:

Noticing Black Mold

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Black mold has a mildew or musty smell. If your building smells like this, try to follow the smell to the source of the mold. If you cannot see the mold, it may be behind a wall or in another well covered space.^{[2]
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Observe the color of the mold. Black mold is, well, black. Other molds are often white, green, yellow, or any number of colors, and they can be dangerous, too. Also note that black mold commonly refers to stachybotrys atra, but there are other molds that are black in color.^{[3]
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- Stachybotrys atra can also be found in colors other than black.
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Black mold will have a wet, slimy texture. Other molds can have a light, fuzzy texture. Avoid touching the mold with your bare hand. Observe the texture by wiping the mold with a towel or other material.^{[4]
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Method 2

Method 2 of 3:

Looking in Mold-Prone Areas

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Mold typically grows in well-saturated areas. Basements, bathrooms, kitchens, and garages are commonly invaded by black mold. If you suspect mold in your building, start looking in the rooms that hold the most water.^{[5]
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Even if an area is not normally water-prone, a leak can lead to mold. Leaky water pipes are often culprits, but you can have other sources of water, too. If your air conditioner is not properly drained and insulated, it can leak water. This can result in black mold around the leak.^{[6]
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Porous materials such as grout are often used to join two slabs or panels. For example, kitchen and bathroom tiles often have grout between them. If water frequently gets into the pores in the grout, black mold can grow there.^{[7]
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Sealants can also be prone to growing black mold. Sealants are often used in high moisture areas (e.g. around your shower). Because of this, black mold can set up and grown on a sealant, such as calk.^{[8]
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Black mold naturally grows on materials containing cellulose. These are plant based materials such as paper, cardboard, and wood. Keep a close eye on any paneling or file cabinets that get wet. Any wood, drywall, carpet, or cloth can easily grow black mold under moist conditions.^{[9]
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Method 3

Method 3 of 3:

Involving a Professional

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Call a local business that offers mold removal services. Many professionals will do a mold inspection for free. If no mold is found, there is no cost to you. If the inspector finds mold, they can help you remove it.^{[10]
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Large amounts of black mold may be difficult for an untrained person to remove. If any area is missed, the mold spores can recolonize and the mold will grow back quickly. A trained professional will ensure that the entire area is mold-free.^{[11]
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Mold spores can be dangerous if inhaled or ingested, but this varies person to person. Allergies are typically responsible for a person’s reaction to mold. To be on the safe side, wear a mask and gloves. Be sure that you clean the entire area to get rid of any microscopic spores that could start a new colony of mold.^{[12]
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Expert Q&A

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Question

How do I avoid outdoor mold?

Alan O. Khadavi, MD, FACAAI
Board Certified Allergist
Dr. Alan O. Khadavi is a Board Certified Allergist and a Pediatric Allergy Specialist based in Los Angeles, California. He holds a BS in biochemistry from the State University of New York (SUNY) at Stony Brook and an MD from the State University of New York Health Science Center at Brooklyn. Dr. Khadavi completed his pediatric residency at Schneider Children’s Hospital in New York, and then went on to complete his allergy and immunology fellowship and pediatric residency at Long Island College Hospital. He is board certified in adult and pediatric allergy/immunology. Dr. Khadavi is a Diplomate of the American Board of Allergy and Immunology, a Fellow of the American College of Allergy, Asthma & Immunology (ACAAI), and a member of the American Academy of Allergy, Asthma & Immunology (AAAAI). Dr. Khadavi's honors include Castle Connolly’s list of Top Doctors 2013-2020, and Patient Choice Awards "Most Compassionate Doctor" in 2013 & 2014.

Alan O. Khadavi, MD, FACAAI

Board Certified Allergist

Expert Answer

One of the best ways is to avoid going outside right after it rains when mold spore counts are highest.

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Can I remove black mold myself?

Susan Stocker
Professional Cleaner
Susan Stocker runs and owns Susan’s Green Cleaning, the #1 Green Cleaning Company in Seattle. She is well known in the region for outstanding customer service protocols — winning the 2017 Better Business Torch Award for Ethics & Integrity —and her energetic support of green cleaning practices.

Susan Stocker

Professional Cleaner

Expert Answer

Avoid removing black mold yourself. Bring in a professional to clean black mold because if the spores are released, it is dangerous to your health. If you do try to remove it yourself, seal off all the affected areas and wear heavy protective gear. Also, use proper mold-killing chemicals — bleach does not kill mold.

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How do you know if mold is black mold?

Susan Stocker
Professional Cleaner
Susan Stocker runs and owns Susan’s Green Cleaning, the #1 Green Cleaning Company in Seattle. She is well known in the region for outstanding customer service protocols — winning the 2017 Better Business Torch Award for Ethics & Integrity —and her energetic support of green cleaning practices.

Susan Stocker

Professional Cleaner

Expert Answer

Black mold has a distinct smell, which is close to dirt and the underside of wet, rotting leaves. The mold is also, of course, black in coloring.

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Tips

Look for other molds near the black mold.^{[13]
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