A Accredited Mold inspection Service would like to answer some common questions on toxic black mold identification. Also, further down, you will find even more photos of toxic black mold. Most of the images are from our own inspections.

Toxic black mold is a specific type of black colored mold, it’s scientific name is Stachybotrys Chartarum. Other black molds grow indoors and can be confused with Stachybotrys. It’s common name is toxic black mold or toxic mold because it contains some extremly bad toxins, but will likely not poison you. It typically causes allergy and asthma problems in most people.

A knowledge of toxic molds appearance and preferred habitat in the home can help you do at least a preliminary possible identification of this mold. It will not be a guaranteed identification of toxic mold, but it can sometimes give you a start.

Like many molds, when it first stars out it grows as fuzzy white fibers forming round or irregular colonies that look a little like cotton. To see this mold looking like white cotton is rare outside of the lab because it is often well hidden and goes unnoticed when it is young and without spores in the home.

Later as it matures and starts producing spores in the older center of the colony it will gain color. It might start looking a little greenish, or gray or black in the center where the spores are. At this stage it may be white around the edges.

Here is a perfect example of a young colony just starting to form spores in its older center. As it ages the spores will spread closer to the edges bringing dark coloration with it. Common to see in a petri dish, rare to see in the home. 

 

As it fills with spores the microscopic black spores give it it’s mature characteristic deep black appearance. By the time you see the mold in your home it is typically very dark black in color. It is sometimes darker black than other black molds.

Let me take a short break and tell you about some cool products. 

Further down the article resumes discussing toxic black mold identification and shows some images of actual toxic black mold.

 

 

This newer variety of do it yourself mold test kits seen above is by My Mold Detective. It will not give you the fun of watching the mold grow, but it is similar to what mold inspectors such as myself use. It works much better at successfully identifying the presence of toxic black mold in your homes air. They also do a much better job of telling how many spores are in your air.

 

 It often exhibits a circular growth pattern, forming round colonies of about less than an inch to many inches across.
Also, the mold often forms concentric circles of one circle inside another circle as shown in the photo. I know of no other mold that grows like this outside of the lab.

In this image we see concentric circles like a bullseye pattern of mold found sometimes in the field is seen of a colony of Stachybotrys grown on paper. Not a common pattern but it happens. 

Most of the times all you will see is dark black irregular patches a few inches to several inches across with no regular circles and no concentric circles.

In the home it is often reported to be shiny or slimy in appearance, however, from personal experience, this is only true when the mold is wet. It is wet most of the time because it requires very wet surfaces for growth. If the leak has been fixed the mold dries out and then it looks dry and powdery in appearance.

 

 

found during mold testing in
Lake Worth.

Stachybotrys found behind a baseboard in a school’s flooded AC closet in the Florida Keys.

A cardboard box and some paper on a wet AC closet floor in the same school AC closet in the Keys. 

Toxic Molds Preferred Ecological Niche

When it grows on drywall, it is actually growing on the thin cellulose rich paper that coats both surfaces of the drywall.

 

It takes its time, it is not a very fast growing mold. If you depend on a petri dish home test kit to identify this mold it might not work out well. By the time the mold starts to grow the sample may have already been analyzed and tossed in the laboratory garbage.
That is one reason why it is best to utilize non viable sampling methods for this type of molds identification.

It takes an extended period of time to grow indoors, such as many weeks or a few months as opposed to a few weeks or days.
When the housing market crashed, I inspected many foreclosed homes. Foreclosed homes that had been empty for about two or three years often had very large amounts of this mold. It seems to crowd out the initial faster growing molds that are eventually replace in many areas by toxic black mold.

Are All Black Molds Toxic Black Mold?

Aspergillius niger
Can be confused with Stachybotrys very easily as it looks a lot like Stachybotrys, and grows in the same severely water damaged cellulose rich habitats as Stachybotrys.

Cladosporium
Can be confused with Stachybotrys as it looks like Stachybotrys, and sometimes grows in the same severely water damaged cellulose rich habitats as Stachybotrys. But quite often grows in low cellulose low nitrogen environments like on metal, plastic, fiberglass, aluminum fences, live tree leaves, concrete. These are places that Stachybotrys do not readily colonize.  If you have mold growing on one of the above surfaces it is likely Cladosporium and not Stachybotrys. Cladosporium loves condensation, it grows around window condensation and AC duct and AC register condensation quite often. If you have mold around light condensation it may be Cladosporium.

Nigrospora 
I am sure it grows indoors sometimes but only one time I took a sample of mold and analyzed it and found it to be Nirgospora growth. It looks like Stachybotrys to the unaided eye. It was growing on a wet carpet near a window. Sure a few of its spores are commonly found floating in indoor and outdoor air. But as stated it is not typically found growing as a visible mass or colony indoors in my experience.
This is after 17 years of testing mold in home! Thus, if you see black mold colonies growing indoors it is rarely Nigrospora.

Alternaria
The above comments about Nigrospora apply to Alternaria, If I remember correctly, I have found this mold growing as a visible colony about two times in 17 years. It looks like Stachybotrys to the unaided eye. The spores are commonly found floating in indoor and outdoor air but I just have not found much of it growing in the form of visible colonies indoors very much. Thus, is you see black mold indoors it is likely not Alternaria.

This mold is called toxic because of the very potent trichothecene toxins it contains. In my experience and opinion, and based on my research, exposure to the amount of toxins required to cause a toxic reaction may be quite high. No one can say for sure how much toxins from toxic mold is require to cause a toxic reaction. As a result of the required high dose people do not commonly  have toxic reactions to this or any toxic mold unless toxic mold in growing in food.

Stachybotrys is problematic because regardless of toxic reactions or not, people often have health reactions to it. People often have upper respiratory reactions that resemble colds or allergy or asthma. If you have to deal with allergy or asthma every time you go into your home you will understand why it is so important to deal with toxic mold and all molds.

Also, this mold is a water damage indicator, if it is found in your air, then you likely have some severely water damaged building materials someplace in your home. Sometimes the damage is hidden in a crawlspace or wall/ Spores are the first indicator of a hidden water and mold problem.

If you are trying to sell your home and a mold inspector finds these spores in your homes air then it will be very difficult to sell your home. The stigma and fear attached to this specific type of mold can really kill a real estate deal faster than your realtor can say to your buyer “oh buddy that’s just harmless mildew ignore it.”

If you have mold your best solution is to have a professional mold inspection done so the problem can be identified and recommendations can be made by a non-bias inspector. Next a contractor must repair the water intrusion problems. Finally, a mold remediator must remove the moisture and remove the mold.