Gateway/Stachybotrys chartarum (black mold)
Stachybotrys chartarum (black mold)
The greenish-black mold usually meant by "black mold": what it needs to grow, what is and isn't known about health effects, and how it is removed.
| Kingdom | Fungi |
|---|---|
| Common name | Black mold, toxic black mold |
| Grows on | Wet cellulose materials: drywall paper, ceiling tile, wood, cardboard |
| Needs | Prolonged moisture, typically days to weeks of wetting |
What it is
Stachybotrys chartarum is a mold (a microscopic fungus) that appears greenish-black and often slimy when wet. It is the species most people mean by “black mold”, although many common indoor molds, such as Cladosporium and some Aspergillus species, are also dark. Color alone does not identify it; a laboratory has to look at a sample.
Where it grows indoors
Stachybotrys needs materials rich in cellulose and a lot of water for a long time. It is typically found on the paper facing of drywall, ceiling tiles, wood and cardboard after a leak, flood or condensation problem has kept them wet for days or weeks. That is why it shows up behind walls after slow plumbing leaks, in basements after flooding that was not dried, and under flooring that stayed damp. It rarely appears on materials that were dried promptly. See conditions for mold growth.
Health effects
Stachybotrys can produce mycotoxins, including trichothecenes. The U.S. Centers for Disease Control and Prevention (CDC) says mold can cause a stuffy nose, sore throat, coughing or wheezing, burning eyes or a skin rash in some people, with more severe reactions in people with asthma or mold allergies. In the 1990s Stachybotrys was suspected in a cluster of infant lung bleeding cases in Cleveland, but a 2000 CDC review concluded that the association was not proven. CDC guidance is the same for every type of mold: remove it and fix the moisture problem, rather than treating one color or species as uniquely dangerous.
If anyone in the home has symptoms, talk to a doctor. We are a restoration company and do not give medical advice.
Testing
Identifying the species requires a surface sample (tape lift or swab) or an air sample analyzed by a laboratory. Testing is most useful when growth is suspected but not visible, when a buyer or insurer needs documentation, or to confirm a remediated area is clean (clearance testing). When growth is visible and the moisture source is known, testing usually does not change the remediation plan.
How it is removed
Remediation follows the IICRC S520 standard: fix the water source, set up containment and negative air pressure, remove contaminated porous materials such as drywall and insulation, HEPA-vacuum and clean remaining surfaces, dry the structure, and verify. Painting over or spraying growth without removing it does not solve the problem.
Key takeaways
- Stachybotrys grows on cellulose materials that stay wet for days or weeks; prompt drying prevents it.
- Color does not identify mold; only a lab can confirm the species.
- The CDC treats all indoor mold the same way: remove it and fix the moisture.
Related glossary terms
- Mold conditions 1, 2 and 3
- Surface sample
- Air sample (spore trap)
- Containment
- Negative air pressure
- HEPA filtration
- Clearance testing (post-remediation verification)
- IICRC S520
Related services and guides
Identifiers
References
- CDC: About mold and your health
- CDC MMWR (2000): Update on pulmonary hemorrhage among infants, Cleveland
- EPA: A brief guide to mold, moisture and your home
- Wikipedia: Stachybotrys chartarum
Reviewed by Jake Lusby, owner of Gateway Water & Mold. Part of our entity reference pages. See our editorial policy to report an error.
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