How Bad Is Black Mold, Really?

By: Melanie Radzicki McManus  | 

black mold on wall
Black mold is shown on this wall. Regardless of color, you want to remove mold from your house. onebluelight/Getty Images

You don't want mold in your home. Black, green, orange, yellow — no matter the color, it's all undesirable. Yet you don't necessarily have to panic if you see it growing on your walls or windowsills. Because while mold can negatively affect your health, and sometimes dramatically, you may suffer no ill effects at all from mold exposure.

Mold is a type of fungus, and it's everywhere — indoors, outdoors and even in the air. That's not too surprising when you consider there are more than 100,000 types of mold in existence, and possibly even millions. Mold gets into homes and buildings through open windows, doors, vents and ductwork. It can also attach itself to your clothes or pets when you're outside, so you inadvertently bring it indoors with you.

Once indoors, mold grows wherever there's a lot of a lot of moisture. That's why you'll often see mold around leaky windows or pipes, or on drywall after flooding. It also grows easily on paper and on fabric, carpet, upholstery, insulation and even in dust.

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Is Black Mold the Worst?

Many people believe something called "black mold," or "toxic black mold," is a specific type of noxious mold that can severely sicken or even kill you because it releases noxious mycotoxins or mold poisons. But that's not totally accurate. First, molds of all colors can cause illness. And second, there are many types of black-colored molds. The one most people have in mind when they refer to black mold, or toxic black mold, is Stachybotrys chartarum (S. chartarum), a greenish-black mold.

Research published in Analytical and Bioanalytical Chemistry suggests S. chartarum may be linked to serious health problems such as mycotoxicosis, or mold poisoning. Other possible ill effects include body aches, headaches, memory loss, mood swings and nosebleeds. But the science isn't definitive. A 2017 report published in Clinical Reviews in Allergy & Immunology states, "There is no scientific evidence that exposure to visible black mold in apartments and buildings can lead to the vague and subjective symptoms of memory loss, inability to focus, fatigue, and headaches that were reported by people who erroneously believed that they were suffering from 'mycotoxicosis.' Similarly, a causal relationship between cases of infant pulmonary hemorrhage and exposure to 'black mold' has never been proven. Finally, there is no evidence of a link between autoimmune disease and mold exposure."

Experts say it's important to note that all types of mold may pose a health risk to certain people, especially if they are exposed to large quantities of it. Those most at risk for mold-related health issues are people with allergies, asthma, preexisting lung conditions and compromised immune systems; e.g., people undergoing cancer treatments or transplant patients. Infants, kids and older adults are also more at risk, as are people with certain chemical and genetic factors. However, there isn't a test that can determine a link between Stachybotrys chartarum and certain health symptoms, notes the Centers for Disease Control and Prevention.

Allergy sufferers who come into contact with mold may develop a runny nose, watery eyes, dry cough, skin rashes, sinusitis and other respiratory issues. Those with compromised immune systems or lung disease could develop fungal infections, while people with respiratory disease may have difficulty breathing. Some suffer for years.

Marie Sterling (not her real name) has been struggling with health issues for 14 years since coming in contact with mold. Despite seeing some of the nation's top mold doctors, her health has never been the same. "I am still permanently sick," she says. "Mold is the worst."

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What to Do if You Find Mold

It's pretty easy to determine if you've got a mold problem in your home, because you will usually see or smell it. There's generally no need to do any kind of testing or sampling, according to the Environmental Protection Agency. And you typically don't need to hire someone to remove it, either, unless you've got a significant area covered in mold — say, larger than 10 square feet (3 square meters). For typical infestations, here's what to do.

  • Remove any moldy items that were soaked and can't be dried thoroughly and properly (carpet, insulation, drywall, etc.).
  • Scrub mold from hard surfaces with a commercial product or a bleach solution of 1 cup (or less) of bleach to 1 gallon (4 liters) of water. While cleaning, wear non-porous gloves and protective eyewear, and open windows and doors. The mold should not return after cleaning (unless you have ongoing moisture problems.)
  • If your home was flooded, dry and clean it within 48 hours of the flooding.

Mold doesn't grow unless there is moisture. To keep mold from returning, fix any water leaks. Make sure your bathrooms, laundry room and kitchen are well ventilated. During humid summer months, use an air conditioner and dehumidifier. Don't carpet moisture-prone areas, such as bathrooms and the basement. Your home's humidity level should remain between 30 and 50 percent year-round. And check that your kitchen, bathroom and clothes dryer vents are all vented to the outside of your home.

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