What is Mold?

Mold, also spelled “Mould,” has been around for millions of years. It is even discussed in the Bible in Leviticus 14:33-54. Giving us specific remediation instructions and warnings about spreading mildew/mold in homes. 

Mold are organisms that may be found indoors and outdoors. “They are part of the natural environment and play an important role in the
environment by breaking down and digesting organic material, such as dead leaves and trees. Sometimes people refer to mold as the earths recycling system.

Mold is “also called fungi or mildew, molds are neither plants nor animals; they are part of the kingdom Fungi.” Some of the common indoor molds are…(3) (These are the genus of molds not the specific species)

• Cladosporium

• Penicillium

• Alternaria

• Aspergillus

Mold spores are ubiquitous; they are found both indoors and outdoors. Mold spores cannot be eliminated from indoor environments. It is common for mold spores to be present indoors because they come inside with you each time you open the door. What is not common and should not be occurring indoors is mold growth! Mold spores will be found floating through the air and in settled dust; however, mold will not grow if moisture is not present. Mold growth is a sign of a moisture problem that should not be occurring. 

Some molds have spores that are easily disturbed and settle repeatedly with each disturbance. Other molds have sticky spores that will cling to surfaces and are dislodged by brushing against them or by other direct contact.(7)

Mold is not usually a problem indoors — unless mold spores land on a wet or damp spot and begin growing. As molds grow they digest whatever they are growing on. Unchecked mold growth can:

• Damage buildings and furnishings

• Rot wood

• Damage drywall

• Cause structural damage to buildings

• Cause cosmetic damage, such as stains, to furnishings

Settled Mold spores may remain able to grow for years after they are produced. In addition, whether or not the spores are alive, the allergens in and on them may remain allergenic for years.(7) 

The potential human health effects of mold are also a concern. It is important, therefore, to prevent mold from growing indoors. (4) 

How do Molds Reproduce?

Molds can multiply by producing microscopic spores (2 – 100 microns [μm] in diameter), similar to the seeds produced by plants. Many spores are so small they easily float through the air and can be carried for great distances by even the gentlest breezes. The number of mold spores suspended in indoor and outdoor air fluctuates from season to season, day to day and even hour to hour.(4) These spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces that are wet. There are many types of mold, and none of them will grow without water or moisture. “The key to Mold Control is Moisture Control.” (1)

What does Mold look like and where do they grow in the home?

Mold growth, which often looks like spots, can be many different colors, and can smell musty. Mold grows well on paper products, cardboard, ceiling tiles, and wood products. Mold can also grow in dust, paints, wallpaper, insulation, drywall, carpet, fabric, and upholstery. (2)

Magnified mold and mold spores (4)


What are Mycotoxins?

As molds grow, some (but not all) of them may produce potentially toxic byproducts called mycotoxins under some conditions. Some of these molds are commonly found in moisture-damaged buildings. More than 200 mycotoxins from common molds have been identified, and many more remain to be identified. The amount and types of mycotoxins produced by a particular mold depends on many environmental and genetic factors. No one can tell whether a mold is producing mycotoxins just by looking at it.

General interest in mycotoxins rose in 1960 when a feed-related mycotoxicosis called turkey X disease, which was later proved to be caused by aflatoxins, appeared in farm animals in England. Subsequently it was found that aflatoxins are hepato- carcinogens (a substance or agent causing cancer of the liver (6)) in animals and humans, and this stimulated research on mycotoxins.(5)

Mycotoxins are secondary metabolites of molds that exert toxic effects on animals and humans. The toxic effect of mycotoxins on animal and human health is referred to as mycotoxicosis, the severity of which depends on the toxicity of the mycotoxin, the extent of exposure, age and nutritional status of the individual and possible synergistic effects of other chemicals to which the individual is exposed. The chemical structures of mycotoxins vary considerably, but they are all relatively low molecular mass organic compounds.(5)

One of the things that many people get frustrated with is that mainstream medical doctors don’t know much about Mold illness!?! This is because “Mycotoxicoses are usually insufficiently treated in medical textbooks and are not covered in curricula of many medical schools.” (5)

Sometimes the news media uses the terms “toxic mold” and “black mold” to refer to molds that may produce mycotoxins or for a specific mold, Stachybotrys chartarum. Molds that produce mycotoxins are often referred to as toxigenic fungi.(4)

What is that Moldy Smell?

Some compounds produced by molds have strong smells and are volatile and quickly released into the air. These compounds are known as microbial volatile organic compounds (mVOCs). Because mVOCs often have strong or unpleasant odors, they can be the source of the “moldy odor” or musty smell frequently associated with mold growth.moldy odor suggests that mold is growing in the building and should be investigated. (4) Just because you don’t smell a moldy or musty smell, does not mean that there may not be a mold problem. If people are reporting health issues that don’t seem to go away or you have any known past or present water or moisture problems in your home or place of work, think Mold. Always get it inspected by a state licensed professional in order to rule out if there is or is not a mold problem.

Should you have the mold tested?

You do not need to know the type of mold growing in your home, and the CDC does not recommend or perform routine sampling for molds. No matter what type of mold is present, you should remove it. Since the effect of mold on people can vary greatly, either because of the amount or type of mold, you can not rely on sampling and culturing to know your health risk. Also, good sampling for mold can be expensive, and standards for judging what is and what is not an acceptable quantity of mold have not been set. The best practice is to remove the mold and work to prevent future growth. (2)

Situations where mold samples are Needed or more than likely Needed.

  1. Medical reasons – Identifying what type of mold genus or species and if mycotoxins are present in your indoor environment may help your doctor understand what you have potentially been exposed to. But at the end of the day, you should always seek a medical professional that can test you properly for mold/mycotoxin exposure. See the list of doctors in Texas that can test and treat you for mold exposure here. 
  2. Legal reasons – If you are pursuing legal action, most attorneys will need to see the analytical data from mold samples in addition to the mold assessment report or protocol in order to determine if you have a case and to also help you build a case.
  3. Post Assessments – If you are needing to see if remediation was indeed successful (which we always recommend doing), samples will be taken as part of the post assessment to help the mold consultant determine if remediation was indeed successful. 

Note: In order to avoid paying a mold consultant to return to take samples in cases where you are unsure if you need samples taken. It is okay to ask your mold consultant if they would be willing to take a few samples and hold them for 48 hours; in order to give you time to decide if you would like them to be submitted. Some will do this. Just ask them what type of fee they may charge. 


What areas have high mold exposures? (3)

• Antique shops

• Greenhouses

• Saunas

• Farms

• Mills

• Construction areas

• Flower shops

• Summer cottages


1. https://www.epa.gov/mold/brief-guide-mold-moisture-and-yourhome
2. https://www.cdc.gov/mold/dampness_facts.htm
3. https://www.cdc.gov/mold/faqs.htm
4. https://www.epa.gov/mold/mold-course-chapter-1
5. https://www.who.int/bulletin/archives/77(9)754.pdf
6. https://www.merriam-webster.com/medical/hepatocarcinogen
7. https://www.epa.gov/mold/what-are-molds


About the AuthorEmily Rachal

Emily Rachal is co-owner of Texas Mold Inspectors, (or TMI), along with her husband, in the Houston, TX area.  After her family’s devastating experience that not only injured her whole family, but also resulted in the loss of their youngest son Malachi, she and her husband have dedicated their lives to now educating and assisting families affected by toxic mold with their state-licensed mold inspection company.

Emily is the founder and owner of MAM. Additionally, she has recently started a non-profit organization in the name of her youngest son, called Malachi’s Message Foundation, to aid in financial support and offer hope to families who feel isolated and are unable to afford all the complex obstacles of overcoming a toxic mold exposure.

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