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What Is Black Mould?

Uncategorized Jan 21, 2020

Black mould has become a bit like the famous celebrities Taylor Swift or Kylie Jenner.  Everyone has heard about it or thinks they know a bit about this fungus. 

In the world of pop culture fungal microbiology, BLACK MOULD is spoken about with reverence as the INVISIBLE ILLNESS CAUSED BY TOXIC FUNGUS…but what is it, what does the science say, and what can you do to separate the fact from fiction?


Three women working in a horticultural factory were handling some pots made from recycled paper.  The women developed inflamed, swollen fingers and scaling of the skin.  This is an inflammation reaction and was caused by handling the pots that looked mouldy.  This article appeared as the first published paper on black mould illness indexed in PubMed in 1997.

They found that when spore traps were used to assess the working environment, that when the mouldy pots were moved the levels of Stachybotrys were dispersed into the air showing levels of up to up to 7500 spores per cubic metre of air. Imagine now what having water damage in your home could be doing to you?


- Black mould is a catch-all term that refers to toxic mould that has been linked to building-related respiratory problems.

- The colour of the mould is not the diagnostic.  If you’re wall or ceiling is showing signs of mould and it’s green, then you can’t assume you don’t have black mould.  You can’t tell except with the microscope.

- It’s very common to grow on wood, gypsum and plaster and insulation found on pipes, aluminium foils like wall wrap and wallpaper.  This fungus prefers cellulose-rich substrates containing high moisture levels.

- It’s not the most common mould.  Dominant moulds from water damaged buildings are by rank: Aspergillus, Penicillium, Chaetomium and then Stachybotrys.


- This fungus produces a large range of toxins called: TRICHOTHECENES.

- These bind to ribosomes.  Your ribosomes allow proteins to be built from long chains of amino acids.  This toxin interferes with protein synthesis.

- It’s not the only problem in damp or water damaged buildings. Other factors like the presence of bacteria, cell wall particulates, mycotoxins, non-microbial volatile organic compounds and microbial volatile organic compounds (VOC’s and MVOCs), other proteins and endotoxins can all cause problems for people by different mechanisms.


- Let’s look at it under the microscope.


- Water ingress is caused by 5 things:

(1) Leaks through flat roofs

(2) Rising damp 

(3) Defects in plumbing fixtures and fittings

(4) Extreme indoor condensation

(5) Weather events including storm damage and floods 


- Review the infamous case of the Cleveland infant idiopathic pulmonary haemorrhage (IPH) reports.

- Official response is NO from the Centres for Disease Control and Prevention.



- Stachybotrys has been linked to a range of symptoms called “building-related illness” and include runny nose, cough and irritation to the eyes and throat.

- Controversy about how serious a threat it is.

- Stachybotrys mycotoxins are divided into 3 structural groups: macrocyclic trichothecenes (e.g. satratoxins), atranones, and phenylspirodrimanes.

- They cause strong inflammatory responses.

- Your nose might be the first thing that’s affected because it’s exposed to everything you breathe in.  RHINITIS is the term that covers that runny nose, the stuffy feeling - that might be due to the common cold or an allergy but might also be due to mould!

- Low dose, big effect - also linked to neurologic symptoms

- Foodstuffs like cereals a very real exposure pathway.  For example, the United Nations estimated that 25% of cereals produced worldwide are contaminated by mycotoxins.  Therefore, there is some risk that you are being exposed to mycotoxins in food especially if the animals ate contaminated feed.

- Building materials used in your home might also make your home more or less likely to show black mould problems.  Green building materials are made from recycled sources.  An example is bamboo flooring rather than timber flooring from virgin wood.  Bamboo grows faster than trees do!

- Now think about that composite timber flooring under your tiling in the bathroom?  That’s an example of a green building material that uses recycled content.  In a recent experiment from 2017, ceiling tiles, composite board, plasterboard walls were made wet and inoculated with dusts containing fungi to see what would grow after 2-months. They found that recycled or green gypsum board (plasterboard) was dominated by Stachybotrys fungus.

- In Australia the thunderstorm asthma event in 2016 has prompted the Government to take very seriously the impact of pollens and mould spores that can be stirred up and distributed by weather events.  There’s a new Interim Standard for airborne pollen and mould and this is a welcome addition to the Australian Mould Guideline (2010).


- Some research shows that components of the trichothecene toxin could be Group 3 carcinogens.  However, Group 3 agents aren’t classifiable as carcinogenic to humans. This is because the evidence of carcinogenicity may be inadequate in humans or inadequate or limited to animals.

- BUT: Cancer-related inflammation is considered the "seventh hallmark of cancer"; numerous studies demonstrate that tumors develop and progress within inflammatory diseases.


YES - because it’s absorbed from the skin, airways, and intestinal lining.


- malaise, fatigue, cognitive impairment.

- Although the presence of Stachybotrys is not proof of toxin presence, it’s known that inhaled spores causes chest and upper airway symptoms, fever, reduced white blood cells count and dermatitis.  These symptoms typically start 2-3 days after exposure and can last up to 3-weeks.

- New research is even linking exposure to Alzheimer's and autism.

- Asthma is often an allergic response to mould.


- Building maintenance

- Don’t ignore known problems in the home

- Clean up wet areas

- Use exhaust fans

- Use a dehumidifier to reduce indoor condensation

- Use a portable HEPA air purifier

- Vacuum carpets with a HEPA vacuum

- Increase ventilation especially when it’s warm indoors and cold outdoors. 


All moulds including black mould grows on wet building materials.  Keep your home clean and dry as best you can.  Mould isn’t always visible, and you may need an indoor air quality or mould inspection or assessment or other form of testing. If you need help, call in a professional. 


Indoor Mould, Toxigenic Fungi, and Stachybotrys chartarum: Infectious Disease Perspective.

Facts about Stachybotrys chartarum and Other Moulds. Centres for Disease Control and Prevention.

Exploring Secondary Metabolite Profiles of Stachybotrys spp. by LC-MS/MS.

Fungal Microbiomes Associated with Green and Non-Green Building Materials.

Effects of Mycotoxins on Neuropsychiatric Symptoms and Immune Processes.

The role of inflammation in head and neck cancer.

Cancer-related inflammation, the seventh hallmark of cancer: links to genetic instability.

Stachybotrys chartarum, trichothecene mycotoxins, and damp building-related illness: new insights into a public health enigma.

Stachybotrys chartarum (chartarum = atra = alternans) and other problems caused by allergenic fungi.


Australian Airborne Pollen and Spore Monitoring NetworkInterim Standard and Protocols.

Mass development of Stachybotrys chartarum on compostable plant pots made from recycled paper.

Satratoxin-G from the black mould Stachybotrys chartarum induces rhinitis and apoptosis of olfactory sensory neurons in the nasal airways of rhesus monkeys.

Exploring Secondary Metabolite Profiles of Stachybotrys spp. by LC-MS/MS.


Transcript of video: 

Hello and thanks for joining me this week. Today, we're going to be talking about toxic black mould and black mould has become a little bit like these celebrities, Kylie Jenner or Taylor Swift. We've all heard about it. We think we know a little bit about it, and today I'm going to be revealing why black mould is so well-known in pop culture microbiology, and why it is almost talked about in revered tones as the invisible toxic black fungus. So, what's the science underpinning all of this? What are the facts? What's the history about Stachybotrys, which is the scientific name for black mould.

We're going to be going through that. I'm going to be showing you what black mould looks like under the microscope. We're going to be talking about how it is different to other moulds. We're going to be talking about the mycotoxins that Stachybotrys produces, and I'm going to be giving you a little bit of education about it, and talking about some of the situations that I find in water damaged buildings with Stachybotrys is a significant component of the water damage event. I'm also going to be reviewing some of the academic literature about black mould and Stachybotrys, and discussing what other individuals and groups, like the Center for Disease Control, have to say about Stachybotrys. So, to begin, what is black mould?

Well, essentially, it is a catch all term for all of the toxic moulds, but most people are referring to Stachybotrys chartarum, or Stachybotrys atra, which are the genus and species names for this particular microorganism. And yes, it is black, and on the bottom left hand side you have a screen grab from my microscope showing black mould. However, the color of the mould, when you find this in your water damaged building, is not necessarily a good indicator to tell you whether or not your property is indeed affected with Stachybotrys. You can only tell by looking under the microscope. It is a very common water damage mould. It's not the most common.

In fact, Aspergillus and penicillium and Chaetomium are other more common fungi, but Stachybotrys is definitely found and has a preference for cellulose rich building materials like timber, wood, wallpaper, and plasterboard. And later on in this live stream, I'm going to be talking about other recycled or green building products that also are a preferred food source for Stachybotrys. So, how does black mould hurt you? Stachybotrys produces these toxins, a mycotoxin called trichothecene, and I'll show you the chemical formulas soon, but in a sense that's not that relevant. This particular toxin has been linked as a chemical warfare agent, as has satratoxin, which is another secondary metabolite from this particular fungus.

Did you know that the LD50, which is the lethal dose for satratoxin extracted from Stachybotrys or black mould is one milligram per kilogram per weight for these mice. So, therefore it is incredibly toxic. There are a whole bunch of other metabolites that can be extracted from this fungus, including cyclosporine, which is a very, very potent immune suppressant. And this preferentially targets lymphocytes and your lymphocytes are responsible for allowing you to mount an immune response to challenges that your body may be exposed to. So, this is what we're talking about. Toxic black mould or Stachybotrys produces a whole bunch of toxins, all of which have similar, but different chemical structures.

Again, the papers from which I am taking these structural formulae from are going to be listed in the show notes underneath the description for this particular live stream. And I urge you, for anyone with interest in further research into Stachybotrys, and black mould, and water damage buildings, to go through the references and the hyperlinks to find out on your own time. But what do these chemicals do inside your body? Well, let's not talk about the symptoms, but let's get down to the level of inflammation, and these toxins like trichothecene toxins bind to your ribozymes. Your ribozymes are in your cells and responsible for linking together the amino acids to form proteins.

So, essentially, these toxins interfere with protein synthesis. Thought of another way, they interfere with DNA, and your ability of your body to repair itself, and for your cells to divide. So, they are very, very serious toxins, but these trichothecene toxins are not the only risks in water damaged buildings. Hence why I gave the analogy that although black mould is well-known like a celebrity, there are a whole hosts of other, in a sense, [inaudible 00:07:16], and other problems in water damaged buildings, such as cell wall fragments. The bacteria and yeast that can also colonize water damaged buildings. The release of endotoxins, the release of micron and sub-micron-sized cell wall debris, and infect other building element debris in the micron and sub-micron range.

All of these become essentially toxic biological dusts, and these can be inhaled and brought into contact with your mucus membranes, or ingested and become quite a significant immune challenge for you. So, there are also the microbial volatile organic compounds, or the characteristic mould odor. All of these have an impact on your immune system as well. So, although the focus today is on black mould, there are a hosts of other reasons why water damaged buildings and the moulds that grow there can cause you harm. Now, what does black mould look like under the microscope? We are going to move to that now. Okay. This is what we see when I connect my microscope to the camera, and what you can see here is from a spore trap that I took in a typical water damaged apartment that I was asked to inspect a couple of weeks ago.

I'll just make this clear, and I'll stop talking about different aspects of these black mould spores. Essentially, these apartments were on the ground floor, the waterproofing was incorrectly installed. There is a significant legal case under foot at present, and the end result is that these ground floor apartments have taken on unwanted moisture. There had been rising damp like effects, which have breached the building exterior and mould has grown inside the wall cavity and on the plasterboard facing the inside of the apartment. I will show you some of the photographs from this apartment afterwards, but I want to focus on what we see down the microscope, and these are these Stachybotrys chartarum spores, and you can see that even on the spore trap I need to use ... They have three dimensionality.

That's what I want to focus on. So, even though we have captured this from the air, these mould spores need to be considered not as two dimensional objects, or a photo, but they are three dimensional. They have size and mass, and these are the reproductive units that allow the Stachybotrys to disseminate itself and colonize new water damaged areas. You can see mould mycelium that germinates from these spores and then grows from it. Now, essentially, what causes black mould in the first place? Well, essentially, there are five events, or things which contribute to mould growth, and that is, in this situation, building defects, water leaking, especially through flat roofs, rising damp situations, which impact on the integrity of the base of a building.

Defects in plumbing features and fixings. I've been called to numerous properties where pipes have unexpectedly burst, or ruptured, or hoses that were supposed to be new have suddenly burst. This is really serious. It causes millions of dollars of damage. Extreme indoor condensation is the fourth problem, and we also have unexpected and extreme weather events, which impact on underlying building defects and problems in buildings whereby moisture gets in. I'm always asked, "Can black mould kill you?" In order to get to answer that question ... I'm going to answer that question in a second. What I want to do is, I just want to zoom in on what we were just seeing. This was a spore trap that was taken from this particular wall.

You can see that not only has the floor carpet been removed, and the plasterboard has been cutaway to provide an inspection point, but you can see that the companion wall is showing quite extreme levels of visible mould growing on the interior plasterboard, on the base of the window frame, on the skirting board, and there was carpet there and smooth edge in the corner before. All of these interior, or indoor building elements were all impacted by water damage and the mould that formed afterwards. And then, eventually I can use spore traps, and tape lifts, and surface contact plates to collect samples to measure the extent of contamination, and comment on habitability and scope of works for repair and restoration in some cases back to a normal mould ecology.

And so, basically this is the location from which those microscope images were taken. But as I said to you, many people asked me, can mould or black mould kill you? And I want to start with where this came from. Back in the early to mid to late 90s, the Center for Disease Control in the United States reported on some examples of infant mortality that was linked to exposure to black mould, or Stachybotrys chartarum, or atra, in these water damaged building interiors. What happened was that the death of these young children, these infants, was blamed on black mould. So, the CDC reviewed all the studies. Unfortunately, their conclusion was that the studies were flawed.

Their conclusion was that there may be an association between the mould, but they could not give a definitive yes or no regarding the situation, and their conclusion was that further research needs to be done. The good news is that scientists from around the globe have continued to examine Stachybotrys, the toxins that different moulds produce, and have increasingly linked this to inflammation. And we'll discuss in a few minutes about the connection between inflammation and cancer. But I want to look at the next, in a sense, disturbing conclusion made by the CDC regarding the evidence, and I see this again and again.

When various experts are debating, the extent to which a building is water damaged and the potential health implications of this, often, the results are attacked as being statistically unstable. I'm not going to say very much more about this point. All of this documentation is available for you to read online, but these are often criticisms of the environmental results linking a chemical, a toxin, a biological toxin with human exposure, and often times the very clear and obvious connections that do in fact exist that sometimes can be explained away by certain groups. The other criticism made by the CDC was that non-standardized sample collection methods were undertaken by the researchers.

The third point was the burden of proof that often when these homes were reexamined to determine exactly how wet they were, they weren't that wet on re-examination. And so, there was a lack of direct connection between the first response data collection exercise and subsequent data collection exercises. I wanted to highlight this because these criticisms emerge directly in response to the literature on Stachybotrys, the black mould, and unfortunately, new emerging research with other water damage moulds, the same approaches to avoid potential connection are often brought up. Now, let's move on to the more common question. Can black mould make you ill? Well, yes, it definitely can.

Stachybotrys has been linked to a range of what are called building related illnesses. They fall under the sick building syndrome class, and so exposure to Stachybotrys, we see this in mice research as well as research, clinical case studies of humans, that exposure to Stachybotrys, these black mould spores elicits rhinitis, runny nose, cough, irritation to the eyes and throats. As you've just seen with the Center for Disease Control, there is some controversy regarding how serious a threat is. However, I would argue that asthma, rhinitis, cognitive impairment is a very serious health risk. Even though the connection between hemorrhage in infants and black moulds was not supported, there is definitely causal evidence linking these moulds with adverse health.

These Stachybotrys mycotoxins are divided into different structural groups. You would remember the chemical formulae that I showed before. All of them, to a greater or lesser extent, show a very strong inflammatory response. And in fact, your nose is the first thing which comes into contact with these unexpected water damaged environments. And by breathing in these spores or the odors, the volatile organic compounds that they elicit, it can cause a whole series, or a cascade of unwanted inflammatory events. Think of the chronic inflammatory response syndrome that we discussed a couple of weeks ago, as well as interference with your visual acuity or your visual system brought about because of these unwanted health impacts caused by these moulds and mycotoxins. So, just remember low dose, big effect.

However, water damaged buildings are not the only way that you can come into contact with black mould. In fact, the World Health Organization has stated that up to 25% of the world's cereals and crops are contaminated with mycotoxins and the unwanted effects from black mould. In fact, there is a massive industry about mycotoxin testing for this in cereal and tradable crops. So, there is definitely some risk of us absorbing other black mould toxins from foods that we eat or animals that we might eat that have ingested these cereals. So, this is another exposure pathway that should not be dismissed. Now, I want to get on to building materials because different buildings have different propensity to take on water.

There have been some very good studies that have come out in the peer reviewed literature looking at differences between water damage to building elements that are made from recycled elements. So, a classic example of this is bamboo flooring versus hardwood flooring. Obviously, bamboo grows a lot faster than virgin timber, and therefore, it is a great example of a recyclable timber. As well you have composite timber flooring, and again, plasterboard that uses recycled elements within it. Now, if you look up the paper that is in the show notes below this video, you will find that they did a really elegant experiment. What they did is they got a subset of green building materials and a subset of non-green building materials.

And instead of inoculating just one or two well-known fungi onto these substrates, what they did is they collected dust from a building, which was considered to contain a normal microflora, and they use that to inoculate these different building materials. So, what they did is they were made wet and they added the dust to each one of the recycled, or non-green building materials, and they then let them grow for two months. And then, they looked at which micro organisms or which fungi had colonized or were the dominant colonizers. And what they found was highly alarming, and they found that plasterboard, wet plasterboard made from recycled materials is overwhelmingly colonized by Stachybotrys. So, that should definitely make you think twice about ignoring water damage in your home.

Now, I want to briefly mention something about thunderstorm asthma and its implications for public health. Thunderstorm asthma was an event or an extreme weather event, which was particular for Melbourne in 2016. The reason I bring this up because I've talked to you a little bit about the CDC and they're rather negative conclusions regarding the research data and science. I want to make the point that back in 2016, this extreme weather event stirred up a lot of dust and pollen, but it was recognized that it also stirred up a lot of fungal spores. Now, many people were hospitalized and a few individuals lost their life due to this extreme weather event. And so, at the state and federal government level here in Australia, there is now a move towards developing an Australian airborne pollen and spore monitoring network.

And the best thing about this is this is introducing an interim standard and protocol for, in many cases, how to go about doing the data collection, how to interpret it, and how to report it. So, hopefully countries like Australia and New Zealand can spearhead the move towards acceptable criteria for collection of information in order to monitor and classify mould spores in the air. That would be a real breakthrough. In any case, the next question that circles back and something that I'm asked about on the telephone every couple of weeks, does black mould cause cancer? Well, the mycotoxins produced by many fungi, including those from Stachybotrys, are considered as group three carcinogens.

A group three carcinogen, essentially, the link hasn't been proven that it causes cancer in humans, although there may be very good evidence to show that it is carcinogenic to animal cell lines or there is animal data showing causation of carcinogenicity. So, just remember it is a group three carcinogen, but if you look at the symptomatology of exposure to mould, it is an inflammation event. And the oncology literature states very clearly that inflammation is the seventh hallmark of cancer. So, anything that creates inflammation in the body has the propensity towards tumor support, and that's all I'll really say on that because the academic literature and clinical literature can be consulted for further examples of this.

So, is black mould dangerous? Well, of course, it is. It is somewhat dose dependent, but different people have different responses to this issue. It does, to some extent, depend on your local environment, your immune constitution, and your genetics plays a very big part in how your immune system responds to these challenges. What are some of the more common mould exposure symptoms linked directly to Stachybotrys? Taken from the literature, these include malaise, fatigue, and cognitive impairment. Often, even the scientists state that the presence of Stachybotrys is not proof of toxin presence, however, the real person's specific outcomes can't be denied. And so, those individuals exposed to high levels of Stachybotrys often experience chest tightness, respiratory complaint, and a reduction in their white blood cell count.

In fact, one of the first academic papers to appear in PubMed discussed the example of three women who worked in a horticultural facility, and they were handling recycled flower pots made from paper. The skin on their fingertips became blistered, and their fingers became swollen. And this was written up as a clinical case study from Germany, and some scientists went into the horticultural facility, took spore traps and found that there were significant differences in the airborne concentration of Stachybotrys spores when the flower pots were and were not being moved. When they were being moved, they were able to measure seven and a half thousand Stachybotrys spores per cubic meter of air, and what does this mean?

Well, the generally accepted threshold that appears in the academic literature is around about 1000 spores per cubic meter. And in this particular study, they reported only on the concentration of Stachybotrys spores. And so, of course, there is a connection between mould, and spore exposure, and adverse health. New research is even linking mould exposure to autism spectrum disorder, Alzheimer's, and depression. So, the whole point is to control moisture in your property, and there are a number of things that you can do to minimize the likelihood of mould and black mould forming in your property. And, obviously, that is to control the moisture source, cleanup unwanted water, use your dehumidifier. If you have an energy tight building that is prone to high levels of indoor condensation, increase the ventilation. Use your exhaust fans, clean any carpets, preferably with a HEPA fitted vacuum.

Consider the use of a HEPA rated air purifier or air scrubber. This doesn't necessarily perform source removal, but it certainly will reduce the spore load or particulate load inside the building. Of course, raise window coverings in the morning if you are in those types of properties that are prone to high condensation. Just be generally vigilant for changes in water utility bills, or don't overlook building maintenance issues that you should attend to. Water tends to affect building properties at the worst possible time, and they quickly lead to colonization of mould and black mould forming inside your home. So, the take home message is, keep your home and building as dry as possible. In any case, I've enjoyed talking about Stachybotrys chartarum today.

Be aware that it is a very common mould, which is spoken about in the public domain, but it is just one of many moulds that can cause unwanted health impacts. My name is Dr. Cameron Jones. I'm an environmental microbiologist. If you're at all worried about black mould or toxic mould in your living environment, you may need to consult an expert, if necessary. It's better to be safe than sorry. Bye for now, and I'll talk to you next week.



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