Skip to main content
Pure Maintenance

What is Black Mold?

By July 8, 2021December 18th, 2021No Comments

Chances are, you’ve heard of black mold. Black mold is infamous relative to other mold strains because of its relatively high toxicity and how conducive human homes are to its growth. But what is it?

If you are here because you discovered black mold in your house, I’m glad you’ve found us. All sorts of mold can cause uncomfortable and dangerous health problems, but black mold is particularly insidious. In today’s writing, I will review the most important things you need to know about black mold.

Table of Contents

  1. What is black mold?
  2. What does black mold look like?
  3. How black mold grows
  4. Black mold and your health
  5. How to prevent black mold
  6. Black mold removal
  7. Conclusion

What is black mold?

Black mold, or Stachybotrys chartarum, is a mold variety frequently found in homes due to its affinity for dark, damp, cellulose-rich environments.

Because many commonly-used building materials are rich in cellulose, we often see black mold grow in cellars and attics, underneath bathroom sinks, and inside kitchen cupboards. One may even discover it growing inside their walls, growing on wood studs and drywall.

S. chartarum is frequently mistaken for mildew, as both grow in damp environments.

Given enough time, black mold can grow anywhere, but in high-traffic areas that receive ample light, such as in a shower or on a window sill, it is more likely that you will see a strain of mildew that is not S. Chartarum

Exposure to S. chartarum, especially over prolonged periods, can be hazardous to your health.

There is ample research indicating a correlation between exposure and severe, often long-term health problems. While the methodologies of many of these studies preclude concluding about causation, we see additional support for black mold toxicity in an enormous amount of anecdotal evidence. 

S. chartarum is a marker mold.

With many species of mold, small quantities – which is to say, indoor mold levels consistent with baseline outdoor levels – are typical and expected. With black mold and other marker molds, such as Chaetomium and Ulocladium, any level presents a serious hazard. That is because marker molds produce mycotoxins, which, in brief, are toxins marker molds produce as a defense against competitive ecological threats.

The subject of mycotoxins deserves its own article, so I will explore them in greater detail in future writing.

The bottom line: If you live in a house with black mold, take steps to eliminate it as soon as possible.

What does it look like?

As its name declares, fully mature black mold is well known for its black color. Depending on the stage of its life cycle, you may also notice tinges of green or gray. Unlike many other molds, S. chartarum isn’t especially fuzzy in texture. Instead, it sprawls across walls and other surfaces like a dusty stain.

Besides its appearance, you might also notice it for its distinctive musty smell that might remind you of a cellar or attic.

How it Grows

Mold may enter a home in any number of ways. Spores drift in through an open door or window. They can track in on clothes, shoes, or even a pet’s coat. 

Once spores anchor to a suitable growing environment, however, then you have a problem. Spores may have drifted under a bathroom sink, where a leak or the frequent humidity of a steamy shower facilitates stable cultivation. They may lie dormant in your basement until a burst pipe or flood soaks the space, allowing for a spike in its growth.

Whatever the case may be, S. chartarum thrives in dark, damp, cellulose-rich spaces. As such, human housing is a uniquely suitable environment for black mold to grow, which also helps explain why it is a well-known problem for homeowners but is harder to find thriving in the wild.

What is black mold? Black mold is a serious hazard to your health.

S. chartarum & Your Health

Is black mold dangerous? Unequivocally, yes.

Official reports like this 1996 study from the International Archives of Occupational and Environmental Health (IAOEH) assert that “prolonged and intense exposure” to S. chartarum. is associated with “disorders of the respiratory and central nervous systems,” among several others.

This 2021 study from the Institute of Environmental Engineering at the University of Zielona Góra in Poland (IEE) even concludes that “Every single case of the occurrence of S. chartarum is dangerous to the health of the residents”. And these are to say nothing of the countless anecdotal reports of adverse health reactions to black mold exposure.

Many reported black mold symptoms present like common allergies:
  • Stuffy nose & fits of sneezing
  • Itchy eyes and eye-watering
  • Respiratory distress including coughing, wheezing, chest tightness, and an irritated throat
  • A stuffy nose
  • Itchy and irritated skin
More serious black mold side effects may include:
  • Frequent headaches
  • Constant fatigue
  • Cold & flu
  • Sore throat
  • Memory loss
  • Asthma
  • Autoimmune diseases
  • Rashes
  • Nosebleeds
  • Pulmonary hemorrhage
  • In infants, SIDS from long-term & intense exposure, as well as vomiting & diarrhea.
Among the worst stories we’ve heard, long term problems may even include:
  • Respiratory infections
  • Reye’s syndrome (swelling of the brain & liver)
  • Bronchitis (a kind of lung infection)
  • Hepatocellular carcinoma (cancer found in liver cells)
  • Balkan nephropathy (a kidney disorder)

As you can see, black mold toxicity is very real and severe. If you believe you are exposed, I encourage you to seek appropriate medical help, as well as whatever steps are possible to end your exposure to black mold.

How to prevent black mold

The best way to deal with black mold – or any mold, for that matter – is to prevent it! You know by now that Stachybotrys c. loves to grow in dark, damp environments.

Here are a few tips we recommend for preventing mold:
  • Maintain healthy humidity levels in your home. If you live somewhere with high humidity, consider investing in a dehumidifier to keep indoor humidity down. The EPA recommends keeping your indoor relative humidity (RH) below 60%, ideally between 30%-50%.
  • Use, maintain and update ventilation systems in high-moisture rooms. I frequently see bathrooms and kitchens with obsolete, neglected fans or stove hoods. Ensure you follow the manufacturer’s instructions on routine upkeep, especially as it concerns keeping them clean! Excessive dust and oil will create problems. If you are resolving a mold issue in your home and your ventilation appliances are old, consider investing in new ones.
  • Have your home – especially your pipes – professionally inspected. A burst pipe will nearly guarantee the activation of a dormant mold colony, and investing upgrades costs less than dealing with sudden damage.
  • The same goes for avoiding flooding! If you live in an environment prone to floods, take steps towards solutions that mitigate flooding, such as installing and maintaining drainage, sealing cracks & gaps in your walls and windows, and keeping sandbags on hand with which to build an emergency barrier.

Black mold removal

Let’s say it’s too late – the damage is done, and you worry you already have a mold infestation. What can you do?

The first step: Get an experienced professional over to perform a mold test.

We at Pure Maintenance of Santa Barbara use a variety of methods, including tape, spore traps, and ERMI (Environmental Relative Moldiness Index) testing. A reliable inspector will be proficient in these tests.

Next, look at available options for reducing the mold count throughout your home to zero.

Pure Maintenance specializes in unique technologies that accomplish this goal, and I wouldn’t settle for less. 

Many conventional mold remediators will deal with the urgent mold breakout by sealing off the affected space and removing the visible mold colony, sometimes using harsh chemicals, sometimes by demolishing the infested walls and structures.

The limitation of this process is that when mold is agitated, it ejects mold spores in a desperate attempt to preserve its efforts to propagate. The aforementioned methods achieve very little in the way of reducing the total mold load of your home or building, and the next time those spores discover moisture, then your problem will resurface.

On the other hand, Pure Maintenance reduces the mold load within the treated area to nearly zero, which is often lower in relative quantity than the baseline environment.

Not only that, but we also protect your space from mold’s return, guaranteed by Pure Maintenance for up to one year!


Black mold is exceedingly dangerous. Be proactive in preventing opportunities for it to anchor and thrive, like reducing indoor moisture levels in your space and keeping a clean home.

If you notice black mold growing, take immediate action. I recommend looking up your closest Pure Maintenance licensee. If you are in Santa Barbara or San Luis Obispo counties, you know who to call!