Aspergillus Stories

Starting at the beginning, “Aspergillus” is pronounced As-per-jill-us.

Aspergillus is a very common indoor fungus. (“Fungus” is another word for mold.) In my area, probably just about everyone has some Aspergillus in their basement. That said, Aspergillus is still one of the top allergenic molds, and it can also contribute to neurological symptoms, sleep difficulties, inflammation, and more.

Story: “I get a headache every time I walk in my front door.”

There had been a flood in the finished basement. The insurance company had sent out a fire and water restoration firm to set up heaters, dehumidifiers, fans, whatever they did. Unfortunately, this plan didn’t work. Mold continued to grow in wall cavities and under a platform supporting a custom-made bar. I was easily able to document this hidden mold.

The dominant mold appeared to be Aspergillus, though where Aspergillus is found, Penicillium typically is also found. While air samples weren’t that bad, the issue was the mold gases produced by the hidden Aspergillus. These gases permeated into room air and upstairs. This man was like a mini-laboratory to demonstrate that mold gases from hidden areas in a basement could cause headaches upstairs.

I didn’t hear the end of the matter from the homeowner… whether he went back to the homeowner’s insurance company or back to the fire and water restoration firm or what he did. At least he knew what had to be done, and that was upending the platform at the bar and treating the underside of the platform and the underside of the bar and having demolition done at all the water damaged walls in the basement.

When the basement floods, even though carpeting is taken out, the lower part of drywall invariably needs to be removed. Water seeps under base molding and under the drywall into the wall cavity. There it gets trapped. There is no way that it can dry out quickly. With water and nutrient (paper backing of drywall and wood surfaces), mold grows. Mold’s job is to break down cellulose and other organic materials.

  • Lesson: I haven’t seen either drying or spraying of chemicals into wall cavities as being sufficient to prevent the growth of mold. The best plan is to tear out wet drywall before mold starts to grow. Once mold grows, the drywall has to come down. If action is taken relatively fast, just the lower part of the drywall may have to be removed. If mold has been growing for a long time, the entire wall should probably be taken down.

Story: “You need to hear my story.”

This call came in on a Saturday night when I was sitting at my computer. A young man had seen my website and wanted to share the story of his infection with Aspergillus. “Ted” had been an energy rater, trained in blower door testing, use of a thermal imaging camera, and duct tightness testing.

It was the latter testing that got him in trouble, the duct tightness testing. The principle behind this kind of testing is to confirm that ductwork is not leaky. Leaky ductwork allows heat and air conditioned air to escape, leading to higher energy costs. Some energy raters feel that money might be better spent other ways then checking duct tightness, but nevertheless doing this testing is part of the complete protocol.

Duct tightness testing involves opening and sealing vents and taking various measurements under pressure. The energy rater has to climb a ladder to reach vents in ceilings, even high up with cathedral ceilings. He has to seal and unseal these vents as various measurements are taken.

Ted told me that no one had ever said to wear a respirator when he was working at the vents. During the course of his work, he apparently had inhaled too many Aspergillus spores for his body to handle from contaminated ductwork.

First, the headaches started. Eventually an MRI or whatever other test was done revealed Aspergillus growing in his brain. Surgery followed, and the Aspergillus was removed, but he was left with epilepsy. Next, Aspergillus was found in his lungs. He was started on an antifungal medication, and then, when that stopped working, another was tried. He had run out of options when the FDA approved V-Fend, a stronger antifungal medication. At the time of his call, V-Fend was working for him, but doctors had to watch his kidney and liver functions because of side effects from the drug. Not just V-Fend but antifungal meds in general can be hard on liver and kidneys. We’re made of the same things that mold is made up of, so if something harms mold, it’s not good for us either.

  • Lesson: Wear a respirator when you are around mold. It’s easier to prevent fungal infection than to treat it. Of course, who would guess that doing duct tightness testing could lead to such dire consequences? This young chap was paying a heavy price.

Aspergillus is a common mold, usually greenish when you can see the growth. Aspergillus is not the “toxic black mold” (Stachybotrys) talked about in many media pieces. Still, Aspergillus can be lethal to people with seriously compromised immune systems or where the exposure is so great as to overwhelm an individual’s immune system.

Even in the average basement, Aspergillus can increase the “body burden” of toxins through exposure to both the particulates and gases that it produces. Maybe it knocks your immune system down a notch or two, or contributes to allergic symptoms, headaches, and sleep difficulties. You need a crystal ball to answers all these questions.

The prudent approach in a home is to find and eliminate all mold growth – Aspergillus, Stachybotrys and all their moldy cousins. You will never get rid of all spores, because spores come in on your clothing and shoes and float in when doors and windows are opened, but you can eliminate growth. It’s the growth that is the issue, because the growth makes more spores, microparticles, and mycotoxins and gives off mold gases (MVOCs – volatile organic compounds from mold). Don’t worry about the stray spores from outside. They will soon drop to horizontal surfaces where you can damp-dust them off or HEPA-vacuum them.

This whole website (and the Mold tab at is all about finding and safely removing sources of mold growth – all kinds of mold growth. True, some molds are worse than others, but all may turn out to be biologically active in the end. Be proactive in finding and eliminating mold growth.

Guess what percentage of homes I find mold growth in when I do mold inspections? I would say out of 3000-plus homes I’ve inspected, I haven’t found mold growth in maybe a dozen. So what are the chances there is mold growth somewhere in your home??

After inspecting one of these dozen mold-growth-free houses, the homeowner called me a few months later and reported the sad news that their hot water heater had burst and he had just finished tearing out wet drywall. I paused for a moment and then gravely said, “How the mighty have fallen.” He laughed and replied, “The first shall be last and the last first.” We had a good chuckle, but there was no real issue here, because the man knew what to do: pull out the wet materials before mold can gain a foothold.

I should expand a bit on that “mold-growth-free” concept. Again, you and I would need crystal balls to confirm that there is absolutely no growth anywhere in a home, including hidden mold in wall cavities. All we can do is what we can reasonably do to lower the risk of mold growth. Wall cavities, being unconditioned space, may have a little mold. No one would think of gutting a house to clean and encapsulate all wood surfaces in the wall cavities as a precaution.

On the other hand, there are always exceptions to the rule, so it pays to be alert to possible contingencies. Here are some example of places where I have found hidden mold, including lots of hidden Aspergillus, because Aspergillus likes environments such as wall cavities:

  • Inside wall or ceiling cavities where there has been past water leakage. Here, I would drill a 1/4″ hole and stick an extender tube from culture plate air sampling equipment through the hole. Then we wait, to see what grows on the culture plate from the wall or ceiling cavity.
  • Inside wall cavity sheathing of a brick home where the brick was softer than brick usually is. This growth was mainly black Stachybotrys.
  • Inside lower wall cavities of a house on a slab, where the land sloped down toward the house, and water seeped in under the siding.
  • Inside wall and ceiling cavities in a high-rise apartment from water coming down from an apartment above.
  • Inside wall cavities in a one year old townhouse, where apparently the framing had been rained on during construction and walls put up when the wood was still wet.
  • Inside wall cavities in a new finished basement, where walls were put up before concrete was sufficiently dry.
  • While not in a cavities, Aspergillus can grow in an attic that is not well ventilated and where moisture from below gets trapped. I’ve seen it grow on rafters and sheathing, especially where rafters meet the sheathing – like a white or greenish fuzz.

Question: Would mold in wall cavities show up in air samples?

Response: No, because the spores are trapped behind a solid wall. Mold in wall cavities wouldn’t show up in other types of testing, either, such as DNA level testing. The health issue would not be with particulates but rather with mold gases infiltrating into the rooms. These mold gases are biologically active, that is, they can affect your health. Testing for mold gases is available but has not received a whole lot of study (because the tests cost too much). Besides, even if a house tests positive for mold gas…where is the gas coming from? If you don’t know where it’s coming from, you don’t know where to remediate.