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  NOTE: May Dooley passed away in March 2024. This site will remain available as a tribute to her.

Health Effects Linked with Mold Exposures

Thee life cycle of mold spores parallels the life cycle of plant seeds, with each of them being the reproductive bodies of the organisms.

Stages of Mold Growth

  1. A spore lands on a surface that would support growth. From whatever source (water or prolonged elevated relative humidity), sufficient moisture is present to enable growth of the spore.

  2. "Roots" are set down into the nutrient, which often is a wood product. With mold, roots are called “hyphae” (pronounced high-phee). The hyphae are the stomach of the mold. Enzymes are secreted, and cellulose is digested. This provides nourishment to grow on the surface. Branch-like structures of mold growth are also hyphae.

    Tip: If you happen to read a lab report from spore trap sampling, there typically would be a space at the bottom of the chart for the number of hyphal fragments present, that is, for broken up bits of the branch-like structures of mold growth. The level of hyphal fragments would be related to the amount of mold growth in the area. If there are no or only a few hyphal fragments, maybe there is no mold growth nearby.

  3. After a few days, the mold may begin to produce seeds. Aspergillus, for example, grows stalk-like branches with flower-like structures on the ends. Spores come off these structures like beads in a necklace. Like with the term “hyphae,” there are terms for all these parts, but we’ll stay with descriptive terminology.

  4. The spores float away and either get removed through routine cleaning or, if they are lucky, land on a spot with food and adequate moisture, and start to grow.

Categories of health effects related to mold exposure

  1. Infectious - This is when so many spores are breathed in that the immune system can be overwhelmed, and the mold starts to grow in sinus, lung, or other tissue. This is one strong reason for wearing a snugly-fitted P100 or N95 respirator.

    Treatment typically is with an anti-fungal medication, but, since mold is made up of the same compounds that our bodies are made up of, what harms mold can have side-effects for us. Monitoring the liver and kidneys may be needed. Avoiding a mold infection is the more prudent pathway.

  2. Inflammatory - Folk have all sorts of reactions to mold, but inflammation may be near the top of the list. An exposure can put in motion an inflammatory cascade of events.

  3. Allergenic - Some folk react to mold exposure with allergic or asthmatic symptoms. At one house, the teenage son said that he experienced asthmatic symptoms as soon as he got to the second floor of the house. On his own, he discovered dark mold at the rear bottom of his bedroom closet, on the other end of the hall from the stairway. I was called in at that point.

    A tape sample revealed the mold to be Alternaria, and the source was found on the other side of the closet wall. A relatively new shower had been installed, and the worker had apparently forgotten to seal part of the structure, with water leaking down into the wall cavity with every shower.

    Here the mold was hidden. It was in the wall cavity and at the lower back wall of a closet. So what was the boy reacting to when he reached the top of the steps? Mold gases.

  4. Neurological - Symptoms range from headaches and sleep issues to cognitive dysfunctions, including reduction in IQ readings for youngsters. One client could tell you where hidden Stachybotrys was growing by where she felt dizzy. If the Stachybotrys is hidden, what she is reacting to is gases emanating from the mold growth.

  5. Hypersensitivity pneumonitis - Some folk, upon a serious exposure, can have a delayed reaction where they have such breathing issues that they might end up in an emergency room. This may be a condition known as "hypersensitivity pneumonitis." I have some sensitivities to mold and was warned long ago by a physician that I needed to take care, because I was a candidate for this difficult-to-treat condition and that it was by far better not to go over the edge.

    Fortunately, even though I’ve been a mold inspector for 25 years, most houses would not be in a condition to give this sort of exposure, because I come and I go, and because most mold is hidden. The concern is where there is a lot of visible or hidden mold that is disturbed and released to room air.

    I’ve learned the situations that would be of the most concern and I wear a respirator there. For example:

    • Some basements are so moldy that there is visible growth on various items. This is a basement for professional remediation and for not disturbing contents without PPE, personal protection equipment, the most important of which would be a respirator.
    • The homeowners go away for a few weeks without turning off the water, and a leak starts in their absence. At one such house, a hot water pipe in the basement spewed out water for a week or two. When they returned, the house was totaled. There was mold growth on everything, even in wall cavities. And homeowners insurance said? “We’ll pay to fix the pipe.” I linked those homeowners, a young couple who had just bought their starter house, up with an advocacy group that is no longer in existence. I don’t know the end of that story.
    • In a similar vein, a house is abandoned with a roof leak. Whoever wanted to reclaim it called me in, but the house probably should have been knocked down, not reclaimed.

Biologically active parts of molds

"Biologically active" means the mold can affect us health-wise. Here are four components of mold that can be biologically active, especially for mold-sensitive individuals. Mold-associated genes, adequacy of detoxification pathways, and status of the immune system play a part in how one reacts to a mold exposure.


These are what the mold industry focuses on. Count spores, eliminate spores, and get a good post-remediation spore trap test result. Spore trap testing is aptly named. The spores are trapped when they impact on a sticky surface, and then they are counted.

Exposure to spores can elicit allergenic, asthmatic symptoms, with exposure to too many of certain types of spores (such as some Aspergillus species) can result in infection, i.e., growth in human tissue.


Microparticles are broken up bits and pieces of spores, hyphal fragments, and other structures. Microparticles are measured with PCR testing, including the CAP testing with Assured Bio Laboratories and with ERMI and HERTSMI-2 tests. If one spore dries out and disintegrates into 50 little pieces, that spore counts as "50" with PCR.

Research confirms that exposure to different types of microparticles, such as components of cell walls, can foster an inflammatory response in a susceptible person.


Mycotoxins are chemical compounds given off by many molds under certain conditions. Stachybotrys can be particularly toxic because of the strong mycotoxins it produces (trichothecenes). These mycotoxins stick onto spores as a survival mechanism, to discourage the growth of competitors. Fortunately the spores also tend to be sticky and don’t get airborne nearly as easily as those of Aspergillus and Penicillium.


Mold gases are also known as MVOCs, or volatile organic compounds given off by mold. I have long felt that MVOCs are under-rated as causing or contributing to symptoms. To eliminate MVOCs, you have to find and eliminate sources of mold growth. As mold grows (and the more moisture, the more active the mold’s metabolism), it gives off gases, which can then penetrate from growth areas, often hidden, into room air, causing chronic issues for sensitive individuals.

Why aren’t MVOCs studied more? Lab testing is pricey. One lab supervisor told me that some creative research had started in the early 2000s, but when insurance companies largely stopped paying for mold inspections and lab fees, the research dried up.

A mold gas story: I was called in to inspect a two story dormitory for a nonprofit association. Students in the dormitory were complaining of allergic and asthmatic reactions. Discovering the source of the mold was easy: it was a large contaminated crawlspace, with no ventilation. Mold gases were rising upward into the dormitory.

This was a non-profit; they did not have the funds for a huge remediation project. About a month after the inspection, I received a call from the building engineer who announced that they had solved their issues. He said that they had put two exhaust fans in one end of the crawlspace and two vents in the opposite end. Fresh air was brought in, moldy air was exhausted. (This dormitory was in the woods, with no nearby buildings, so they could do that. You wouldn’t want to blow moldy air into a nearby neighbor’s window.)

The building engineer reported that complaints had stopped. Allergic and asthmatic reactions apparently had ceased. What’s the lesson here? The lesson is mold gases. Air samples in living areas were okay, as were tape samples. If spores and other particulates were not infiltrating living areas, then neither were microparticles or mycotoxins. That leaves mold gases.


In addition to spores, there are three other components of mold that can affect us biologically, i.e., microparticles, mycotoxins, and gases produced as mold grows. In the sections on testing options, we will discuss pros and cons of the different types of testing for each of these components.


Before we move on to reading lab reports, I'll tell you the story of how the mold industry started, about 2000. My business was established in 1994, and my accountant had just suggested that maybe I should look for a job, when mold made the headlines. I’ve been busy ever since.

The story starts in Texas, in a large house where one of the homeowners worked in the financial sector. The man started to lose his memory and his ability to multitask. Eventually, he lost his job. No one could figure out what was happening, and then one day, his wife happened to sit next to an engineer on a plane. In their conversation, the engineer suggested that they check for black mold.

Back at home, an inspector did find toxigenic black mold, Stachybotrys, in one bathroom. ("Toxigenic" means capable of producing toxins.) The couple wanted their homeowners insurance to remediate the entire house. Farmers Insurance replied that they would remediate the bathroom, but not the whole house. A stalemate ensued, and the homeowners sued Farmers.

Even though the man had been to a medical specialist in fungal issues, and the specialist concluded that Stachybotrys likely was the cause of his neurological issues, the grounds for the lawsuit were negligence. My guess is that there may not have been sufficient research documentation to sue based on health issues.

A jury trial ensued, resulting in the couple being awarded over $30 million, a figure that I have never understood. Anyway, this amount was reversed on appeal, and they pretty much got their legal fees. The wife, Melinda Ballard, became an advocate and put up a website, at least until she passed on, to help victims of mold issues with homeowners insurance companies. She’s the one I referred the young couple to with the basement burst hot water pipe.

Such a huge settlement, even largely reversed, put mold on the map and gave birth to a new awareness of potential health effects from mold, as well as looking around to see whom to blame in many cases. After a few years, homeowners insurance companies took stock, with many sending out disclaimers saying that mold would not be covered under the homeowners’ policies. They would cover water damage, but not mold. As you can imagine, the line between those two can be very thin.

A second event also caught the attention of the public. In Ohio, there was a cluster of infants who suffered pulmonary hemorrhages, with some fatalities. Stachybotrys was found in the homes of the babies, though results were not conclusive tying the mold to the illnesses. A doctor at Rainbow Children’s Hospital, treated these babies, and, from what I understand, believed in the Stachybotrys link.

I have had a few clients where they, too, became involved with Stachybotrys after a child fell ill. Here are two stories:

A woman was riding in a New York City subway with her baby when a passenger across the aisle spoke to her. “I am a nurse and I don’t want to alarm you, but I’ve noticed a drop of blood from your child’s nose. You need to get off at the next stop and get to an emergency room.”

The unknown good Samaritan was correct. The child had a pulmonary hemorrhage and did survive, but had to be watched day and night until the baby’s lungs were more mature, until eight months of age.

I was called in to look for Stachybotrys in their apartment. Indeed, it was there, in a bathroom plumbing area. They found a new apartment.

Another client has a son who, from an early age, probably around two years old, was diagnosed with a blood disorder and was treated in the oncology ward at a local teaching hospital. The child went through hard times, with spinal taps, etc. The mother was told by one of the physicians that it was believed that this condition was environmentally caused, but that they didn’t know what in the environment might cause it.

The mother got started with research. She found the answer in veterinary science, where horses and cows exposed to Stachybotrys mold came down with this condition, cytopenia or some such thing. She called in a mold inspector who found the Stachybotrys inside the back cavity of the kitchen sink. Nothing was visible on the surface, but a moisture meter was positive for the presence of moisture. She later learned that the cabinet installer had inadvertently ticked a plumbing pipe, causing a slow leak. Once again, it sounds like the health effects were linked with mold gas exposure, since the mold was hidden in the wall cavity.

The family had rented a two-year-old townhouse when the child fell ill. After frustrations left and right, a lawsuit was brought against several parties. Parents arrived at court with a stack of medical bills and reports. (I had become their local mold inspector by then and attended the session with them.) Dr. Dearborn, from Rainbow Children’s Hospital in Ohio, was prepared to testify as an expert witness. Representatives from various insurance companies were in the courtroom, because this case might have had huge implications for their companies.

What happened? The judge ruled that medical evidence had not sufficiently been established for a link between Stachybotrys and this blood issue. He ruled that Dr. Dearborn would not be permitted to testify, and he refused to let the jury know of any health concerns other than asthmatic reactions.

Perhaps 15 years have passed since then, and the boy is now a young man in college, a soccer player, but those earlier years were traumatic.

How much mold is too much mold in a house?

In my opinion, we should have zero tolerance for mold growth in a home. That would eliminate sources for toxic gases and biologically active spores, microparticles, and mycotoxins.

Before moving on to a discussion of Remediation, let’s consider the various Testing Options for detecting spores, microparticles, mycotoxins, and gases.

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