Mold Myths Busted
Myth 1: Mold is all around us, has been for millions of years, and is harmless

He must burn the fabric, the woven or knitted material of wool or linen, or any leather article that has been spoiled; because the defiling mold is persistent, the article must be burned. Leviticus 13:52

Fungi pre-date humankind and are indeed ubiquitous in our environment but have been recorded as far back as the old testament as a source of health problems. A change in building construction from the 1970s on resulted in airtight, but not watertight, buildings which provide the ideal environment for certain species of highly toxic molds to thrive. Additional theories propose that fungi has mutated in the last few decades due to the widespread use of fungicides in agriculture, anti-fungal paints/building materials in construction and the increase of other chemicals in our environment.

Myth 2: It’s just about mold or It’s just about mycotoxins

A microbe by any other name would smell as musty

On the contrary mold is just one organism found in water-damaged buildings that produce airborne inflammatory compounds that trigger and perpetuate a multisystem, multi-symptom illness known as chronic inflammatory response syndrome (CIRS) / mold illness.

Other nasties include bacteria, including MARCoNS, actinomyces (a microbe somewhere between bacteria and mold), viruses and parasites.

Likewise mycotoxins are just one toxin produced by these microbes. Others include endotoxins and exotoxins, microbial VOCs (mVOCs), beta-glucans, mannans, fungal fragments, building VOCs, nanoparticles and more.

From Berndtson, K. et al. (2015).

From Berndtson, K. et al. (2015).

Myth 3: Black mold is the most dangerous mold / Stachybotrys is the worst mold.

It Doesn’t Matter if You’re Black or White

True, Stachbotrys chartarum, (STACK-E-BO-TRIS), Stachy for short, is usually black when using cellulose, such as drywall, as a food source but other toxigenic molds can be any color of the rainbow and range from white, brown, green, red to yellow.

Stachy with its large, sticky spores is not the only mold that can produce toxins. Chaetomium globosum (KEY-TOE-ME-UM) have a similar size, affinity for high water saturation conditions and toxic capabilities. Other molds such as Wallemia sebi and two species of Aspergillus are more easily aerosolized and grow in less water saturated conditions, but can be also problematic in enough quantities.


Moldy Window

Myth 4: Only if you see large amounts of visible mold or smell mold, is it a problem.

What you can’t see can hurt you

While significant visible mold or musty odors are tell-tale signs you have a mold problem, mold in quantities likely to cause health problems can be invisible, either in dust/carpet or hidden in wall or ceiling cavities, HVAC/air conditioning systems, subfloors or basements.

Ideally testing for mold will be by an independent indoor environmental professional (IEP)/industrial hygienist using visual and moisture meter methods with the possible addition of infrared cameras, particle meters and VOC meters. For hidden mold more thorough detective work such as cavity sampling, surface sampling/tape lifts may need to be employed. For the CIRS protocol ERMI/HERTSMI-2 testing is required rather than the industry standard of air testing/culturing of live spores due mainly to myth 5.

Myth 5: Killing mold is the best way to get rid of it

Rage, rage against the dying of the mold

Dead wrong. Deceased mold is actually worse than living mold as when dead the spore will disintegrate into approximately 500 fungal fragments which can then disperse in the air. Both the fragments themselves and the toxins attached to them can be a major source of inflammation when inhaled. Also mold will produce more mycotoxins/mVOCS when being killed or threatened by a biocide.

After the moisture problem or water ingress is dealt with, the area has been contained and porous materials removed then you want to gently remove any remaining mold spores or fragments using microfibre cloths, mild soap/detergent and elbow grease. Sometimes HEPA vacuuming of all surfaces is needed and HEPA air scrubbers can be also used.

Me wary of any remediator who wants to fog, gas or use other biocides (this includes essential oils) to kill mold as their primary remediation strategy. This especially applies to bleach which merely strips the color while adding moisture. Never use bleach, okay?

For more debunked mold myths join the webinar on 29/30 September and signup for Mold Illness Made Simple eCourse when it launches on 13 October.


  • Shoemaker, R. (2010). Surviving mold – life in the era of dangerous buildings.
  • Schwartz, L., Weatherman, G., Schrantz, M., Spakes, W., Charlton, J., Berndtson, K. & Shoemaker, R. (2016). Indoor environmental professionals panel of surviving mold – consensus statement. Surviving MoldFull text.
  • Berndtson, K., McMahon, S., Ackerley, M., Rapaport, S., Gupta, S. & Shoemaker, R.C. (2015). Medically sound investigation and remediation of water-damaged buildings in cases of CIRS-WDB – Consensus statement – Pt 1. Surviving MoldFull text.
  • Vesper, S. (2011). Traditional mould analysis compared to a DNA-based method of mould analysis. Critical reviews in microbiology, 37(1), 15-24. doi: 10.3109/1040841X.2010.506177 PMID 20874612, Full Text