Fatal black mold, Stachybotrys chartarum, can be located in any location that is dark and moist. Black mold is fatal and any drywall and baseboards that are infected must be removed. Black mold releases mycotoxins and causes respiratory problems. You may notice an increase in allergic reactions from high mold levels. Fatal mold can also cause headaches, difficulty concentrating, dizziness and a short attention span.
Search for black mold in areas of high humidity, greater than 55 percent; where there are leaks in pipes; in flood areas; where there are mildewy or musty smells; in damp basements; where humidifiers are running; and where you see rust forming. Poor ventilation can also cause mold to form. Look at damp or wet rugs, indoor clothes lines, carpet or furniture that has been wet. Look at bathroom tile, behind vinyl wallpaper, in crawl spaces and anywhere there are lots of indoor plants. Check the attic to ensure you don't have mold growing from a leaking roof. Look in air conditioning ducts, swamp coolers and on insulation. Mold can even hide inside cabinets.
Identify the smell of black mold. Black mold smells like urine. It will smell musty and mildew, but not unless it is out in the open. If it is growing in the walls, you will not smell fatal black mold.
Look closely at the mold you find. Fatal black mold is dark and slimy. It is greenish-black. You may also find black, gray-brown, white, orange, pink, purple or gray-green mold in the areas where fatal black mold is found. Other molds can be as fatal or more fatal than black mold, so be careful with any type of mold you find. See Resource 1 for photographs of different types of mold.
Test the humidity in your home. Mold grows where humidity is 55 percent or higher. Take your sensor around the house, especially in mold-prone areas, while you are searching for mold.
Send a sample of any mold you find to a biological growth lab. Find mold kits in home improvement stores, but wear protective gear when collecting mold spores. Some tests sample the air, while others want samples of the actual mold. Follow the instructions carefully if you are conducting the test yourself. You can also hire a licensed contractor to test your mold.