All About Mold

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Hidden Black Mold Exposed

If you searched for black mold in-house, or just mold in-house, or toxic mold symptoms, or danger of mold in home, or one of thousands of variations…

…this page has all you need to know about exactly what mold is, how and why it grows, mold symptoms and the health dangers of mold. (For mold inspection and the mold tests that follow it, Go to our mold inspection page. For our mold testing qualifications, go to the Chicago mold inspector page.)

If you are searching on black mold, white mold, toxic mold, you need to find our more about “what is mold?”…

…Since the #1 search term regarding mold on Google is black mold, it’s obvious that many folks know that black mold is dangerous. But not all mold is dangerous, not even all black mold. And not all dangerous mold is black mold. Two of the most commonly associated black molds are species S. chartum and S. chlorohalonata, just two of the 50 know species of the Stachybotrys genus of mold. Commonly found growing in building materials after flooding and other water damage, these variants produce mycotoxins as a by-product of their metabolism. It is the mycotoxins in Stachybotrys (and other mold families) that define the term toxic mold. To complicate matters, other mold species even react with household chemicals to produce Volatile Organic Compounds that can also be toxic (see our VOC testing page for more).

While it is hard to generalize about the bizarre world of fungi (with thousands of mold species, each different in its: dangers and characteristics), it can be said that while many mold species are unhealthy to humans, toxic mold species with mycotoxins are decidedly more hazardous. These species create dangerous poisons that lead to severe disease or even death. For a more complete list of mold species found in American testing environments read our Mold Glossary. For more on the most common mold species found in normal testing, jump to our Common Mold Types with Mold Symptoms & Illness Chart.

If you’re looking with terms like mold in-house (or black mold in-house), mold in basement (or black mold in basement), mold in homes, pictures of mold, what does mold smell like, or any one of hundreds more…

…You know, or strongly suspect, you have mold in the house somewhere and need to know why. Mold needs three things to thrive: 1.) moisture, 2.) A food source, and 3.) time. If you have enough moisture in a house, virtually anything (see chart below) can be the food source for mold. Add enough time, and you have mold in the house. Any dwelling with recent flooding, water overflow, or excessively humid environments will likely develop mold. Mold can also be present If the building has or is suspected of having had a history of significant leak events or even a single event which flooded some areas. Plumbing leaks, roof leaks, ice dam leaks, basement water entry, sewer backup, ventilation problems, or HVAC system problems qualify. (Homebuyers tip: all of these issues should be explored before a home purchase.)

You search for mold health dangers, mold allergy symptoms, mold and asthma, black mold symptoms, mold exposure symptoms, or hundreds more combinations…

…You may have someone in the house with a mold allergy, has asthma, is elderly, and/or with a compromised or weak immune system. For people with those conditions exposure to mold is much more dangerous than others without them. You might see or smell mold in the house and are worried about the dangers or mold, and the symptoms of mold exposure especially black mold, or toxic mold. Below is a chart prepared by Chicago Inspection Agency to outline many common mold types, and the mold symptoms and Illnesses that they can produce or aggravate:

Common Mold Types with Mold Symptoms & Illness Chart
Mold Family Where Found Mold Symptoms & Illness * Mytox

  • any cellulosic material
  • wood
  • wicker
  • hay
  • paper (and on wallboard)
  • cardboard
  •  damp, dark environs (basements, under sinks)

Requires days or weeks on damp surfaces to grow.

  • known carcinogenic
  • dermatitis
  • burning in nasal passages
  • tightness of the chest
  • cough
  • nose bleeds
  • fever/headache/fatigue.
  • inflammation of mucous membranes

  • walls
  • insulation
  • soil
  • clothing
  • damp, dark environs (basements, under sinks)

Most common household mold

  • respiratory disorders
  • ear and eye infections

Worse for those with weakened immune systems.

Some species produce highly toxic mycotoxin Aflatoxin 


  • food
  • dead plants
  • food
  • insulation
  • damp, dark environs (basements, under sinks)  
  • skin lesions
  • keratitis
  • nail fungus
  • sinusitis
  • asthma
  • pulmonary infections

Worse for those with mold allergy, asthma, and weakened immune systems.


  • food
  • walls
  • insulation
  • wet, organic matter




  • stomach problems (ingested)
  • lung inflammation
  • lung alveolitis
  • asthma
  • congestion/coughing
  • eye/nose irritation

Worse for those with mold allergy, asthma, and weakened immune systems.


  • cellulose materials
  • plaster/wallboard
  • wood ceiling tiles

Often a source of hidden mold with undetected moisture sources (leaky roof, windows, etc)

  • eye, nose, throat irritation
  • asthma

Worse for those with mold allergy and asthma


  • humidifiers
  • sink drains
  • AC/HVAC systems

Powerful allergen can produce toxic carcinogen Trichothecene

  • dermatitis
  • eye/skin/nail infections
  • nausea/diarrhea
  • circulatory/nervous disorders.
  • internal hemorrhage 

Worse for those with weakened immune systems.


  • soil
  • spoiled food
  • carpeting
  • air conditioning
  • ductwork

Fast growing, invasive when inhaled

  • respiratory problems
  • asthma
  • flu-like symptoms
  • gastrointestinal problems

Can cause the rare disease  zygomycosis, a severe fungal infection that can affect, eyes, nose, and internal organs.


  • dead plants
  • soil
  • cellulosic materials
  • wallboard/insulation

Unpleasant smelling, can be difficult to locate. Produces mycotoxins so toxic it was once studied for biological warfare.

  • opportunistic fungal infections – nail, subcutaneous
  • rare: toxic mycotoxins induce arthritis, osteomyelitis, peritonitis, endocarditis, pneumonia, cerebritis

Toxic for the immune compromised, post surgical, catheterized, or steroid users.


  • carpeting
  • clothing
  • around windows
  • damp, dark environs (basements, under sinks)

Can grow with less moisture than other molds

  • Respiratory problems
  • Asthma
  • Hay fever

Worse for those with mold allergy, asthma, and weakened immune systems.

Mycotoxin – “Yes” in the field mean the mold produces hazardous toxic metabolites

Independent Panel Discussion on Mold Health Issues

For additional background on mold, this independent video goes into depth to clarify the issues surrounding efforts to identify toxic mold as a national health issue:

Thank you for reading. We hope you now know more about mold in your home. Of course, the only way to rest assured you thoroughly know your family’s mold exposure risk is to have a professional, certified mold inspection. We hope you’ll call Chicago Inspection Agency for a free quote.

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Or, simply pick up the phone, and find out how an affordable,

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