You’ve seen mold, also referred to as mildew, before. Leave a damp article of clothing wadded up so that it’s not exposed to sunlight or other drying conditions, and in a few days, you’ll have a nice crop of mold. The same goes for leftovers in the fridge – you know, the ones that resemble a science project. Mold is pretty common, and most are relatively harmless to the average person, though none are healthy. One type, however, can be deadly: toxic black mold.

What is black mold?

Mold is a fungus that grows in the presence of high humidity. There are literally thousands of mold species, and in fact, they’re the most common form of fungus on the planet. They can grow almost anywhere. Even in arid conditions, they might remain dormant for months or even years, and become active with the right combination of moisture, light, and available nutrients.

Specifically, black mold is Stachybotrys chartarum. It’s most often associated with poor air quality and homes and buildings with water damage. It produces harmful mycotoxins and is responsible for numerous health problems in humans. Toxic black mold might produce several different mycotoxins.

Where does it grow?

Black mold can grow virtually anywhere that’s damp. This includes on paneling, on sheetrock, around windows, in floors and subflooring, in basements, around bathroom tiles, in insulation, on ceiling tiles, and under or in carpet. It can also grow on house plants, on straw or hay, on leather furniture, and on cloth and upholstery. Just about anywhere in your home could be subjected to black mold. It also affects office buildings and schools, often forcing temporary closings until the culprit can be removed.

Toxic black mold is often rampant after major flooding occurs.

How do I know if I have it in my home?

If you have too much moisture in your home, chances are good that you have mold growth. Reasons for excessive humidity and moisture might include roof leaks, leaky pipes, an abundance of indoor plants, or wet carpet.

The mold might be in a visible spot. If so, it appears as a dark green or black slimy growth, as a dark powder, or it could be dry and somewhat scaly. Even if you see no mold, it doesn’t mean it’s not present. Signs include a moldy smell, discolored wall paper, discoloring of walls and ceilings, loosened sheetrock tape, and paint peels.

If family members experience frequent respiratory illnesses, toxic mold might be the cause.

To be sure, you can use a test for mold or hire an inspector. These can be used to test surface areas, the air in your home, or both. These tests and inspectors are usually expensive, and they don’t always tell you the type of mold you have. Since all molds are considered unhealthy, it’s best to go ahead and eliminate the problem, regardless of the fungus species.

How is it dangerous?

Toxic mold can cause a host of health problems in humans. Many people think the mold or mold spores have to be inhaled to cause illness, but that’s not always the case. The mold can also be harmful when it comes in contact with skin or when it’s ingested. Illnesses caused by mold include chronic sinus infection, mild to severe allergic reactions, asthma, and other irritation to the respiratory system.

When molds and other fungi break down substances into usable food particles, they release mycotoxins. The mycotoxins are extremely toxic to humans. They can cause diarrhea, vomiting, eye irritation, nose bleeds, bleeding in the lungs, fever, headaches, sneezing, coughing, breathing difficulties, rashes, dizziness, sore throats, dermatitis, fatigue, cold and flu symptoms, confusion, and a general feeling of malaise.

Some people are more susceptible than others to toxic mold. This includes babies, those with any type of breathing difficulties, and those who have any immune system issues. In hypersensitive individuals, toxic mold can result in neurological damage and in permanent lung damage.

In 1994, 45 Cleveland, Ohio infants experienced pulmonary hemorrhage from inhaling spores from toxic black mold. Ultimately, 16 of the babies died.

How to get rid of it

First of all, you need to identify the source of moisture and repair or remove it. For example, a leaking roof or a leaking pipe can cause mold to grow. If these aren’t repaired, you’ll be wasting your time removing the mold; it will just grow back.

When you’re removing mold in an area, the room should be sealed off. Close the doors and place plastic over any openings, like under doors. Open a window to the outside and use a fan to direct any loosened mold spores to outside.

To clean small areas of mold, mix together one gallon of water, one cup of household bleach, and ¼ cup of dishwashing liquid. Generously apply the bleach mixture to the affected area and let it “sit” for 15 minutes. Wipe the area clean, making sure it’s completely dry. Place all the mold into a plastic bag that can be completely sealed.

When cleaning moldy areas, wear a face mask, safety goggles, gloves, and adequate clothing. If the mold is dry, spores are most likely present. Don’t be tempted to scrape these. The spores will be released into the air, and breathing them is very dangerous.

Large areas of mold, including insulation, carpet, and large areas of ceiling tiles, cannot be cleaned safely or effectively. Your only choice will be to completely replace the moldy substances.

How to prevent it

You can help prevent toxic mold from taking up residence in your home. Keep the humidity in the house low – below 55% relative humidity - even if you have to use a dehumidifier. Avoid placing carpet in kitchens and bathrooms. Rugs used in those areas should be washable. When you re-paint a room, have special mold inhibitors added to the paint. If you spot mold, clean it away properly before it gets out of hand.

Using an HVAC system with a HEPA filter will drastically reduce the amount of dangerous mold spores in your home. It will also remove other allergens, making your home environment much healthier.