Mold killing guide:

This document explains a very common mistake in mold cleanup jobs: relying on bleach, biocides, or fungicides to "kill" toxic mold.

This is a chapter of the Mold Action Guide, a document which provides an easy to understand step-by-step guide for dealing with toxic or allergenic indoor mold and other indoor contaminants: what to do about mold.

The steps in this article series will be sufficient for many building owners who want to do their own mold investigation, mold testing, mold cleanup, and mold prevention in their home or office.

HOW TO KILL MOLD: Should We be Trying to Kill Mold?

Many readers have contacted us to ask about using bleach, fungicides, or biocides as a "mold remediation" step and many mold remediation projects we've seen have placed too much reliance on attempts to spray or gas mold to try to "kill the mold and render it harmless" that we've added this brief article on what's "right" and "wrong" about relying on any spray, gas, chemical, or "treatment" to treat problem mold in buildings.

Here is what the U.S. EPA says about using biocides, bleach, mold killers, mildewcides:

Cleanup and Biocides

Biocides are substances that can destroy living organisms. The use of a chemical or biocide that kills organisms such as mold (chlorine bleach, for example) is not recommended as a routine practice during mold cleanup.

There may be instances, however, when professional judgment may indicate its use (for example, when immune-compromised individuals are present). In most cases, it is not possible or desirable to sterilize an area; a background level of mold spores will remain - these spores will not grow if the moisture problem has been resolved.

If you choose to use disinfectants or biocides, always ventilate the area and exhaust the air to the outdoors. Never mix chlorine bleach solution with other cleaning solutions or detergents that contain ammonia because toxic fumes could be produced.

Spraying, Bleaching, or Killing Mold Does Not Kill All of the Spores

First of all, after spraying or gassing "toxic mold" or "black mold" in a building, the bad truth is that the mold is not dead - at least not all of it. Even if you spray bleach all over your "black toxic mold" you won't kill every single spore.

I've examined bleached mold samples in the lab. I can usually tease out viable spores from the supposedly "dead" mold sample. To kill every single mold spore using bleach, for example, you'd have to use such a high concentration of disinfectant and you'd have to keep it on the surface for so long that more likely you'd damage the structure - and still miss some toxic spores.

This is particularly true when people rely on spraying rather than physically cleaning or removing moldy surfaces or materials.

To be scrupulously fair, if we sprayed a surface with sufficient force as to actually physically clean it (and if we removed all of the sprayed-on liquid and debris, we'd do a credible job of cleaning the surface of problem mold. Of course in fact, you could use water or deck cleaner or a dry product like baking soda for such purposes just as well as a disinfectant.

See our REPORT on MEDIA BLASTING for an example of using a "spray" approach to physically clean a surface.

- Thanks to Arlene Puentes for technical edits.

Killing Mold Spores Leaves Toxic or Allergenic Particles in Place

Second - even if in theory we could "kill" every spore, the assumption that they are unimportant is highly questionable.

"Dead" spores often contain allergens or toxins that are just as harmful to someone breathing them or getting such mold in one's eye or in a cut, as before.

Examples of and research confirming that killing a mold spore does not eliminate all possible harm from that material are given at the end of this article.

Relying on Mold Sprays, Bleach, Biocides, Fungicides Risks Taking an Ineffective "Short Cut" to Mold Removal

Third - when I hear remediators or testers focused on whether mold is "alive" or "dead" we are immediately concerned that they do not understand the best practices regarding mold problem diagnosis and cure.

The object is not to "kill" mold, it is - to remove the mold reservoir in the building by physical cleaning or in cases of items that can't be cleaned, such as drywall, soft goods, carpets, furniture, or insulation, remove the moldy material - to identify the cause and make sure that's been corrected (which in your case you think has been done but I'm doubtful where a crawl space is involved - wet conditions that made part of a building wet have often affected other building areas that are less obvious).

It is Important to Find, Identify, and Remove All of the Problem Mold Reservoirs in a Building

Fourth and very important - we need to be very confident that ALL of the substantial mold reservoirs at a building have been identified and cleaned-up or removed.

My experience is that very often people focus too quickly on the mold that they see, say on wood in a crawl space, and fail to detect an as large or larger and as problematic or more harmful mold reservoir that they didn't "see". Examples of this mold killer approach error include:

• Missing hard to see but important mold contamination: Failure to recognize that other materials exposed to moisture or leaks, such as insulation, have become a mold reservoir, because to the eye the look "clean"
• Failure to identify all of the mold reservoirs in the building
• Mistaking the visible mold for the most problematic mold - a simple identification test of the visible mold may, for example, show that it is a different genera/species from mold showing up in settled-dust tests or air tests in the same building. If that occurs, further investigation is needed.

Hire a Competent Professional for a Thorough Visual Inspection for Problem Mold and Its Causes

SO what you need (and might already have) is great confidence that the expertise of the mold or building inspector and the scope of the investigation have been very accurate and thorough before any remediation project is begun. Otherwise the risk is that you have to repeat the process again later.

Even if you clean or remove problem mold thoroughly, if you do not correct the original cause of mold growth, you are likely to face this trouble and cost all over again.

How Should Small Areas of Mold be Handled?

Small Areas of mold: clean and disinfect surfaces: small areas of mold (less than 10 sq.ft. or less than 30 sq.ft. in some guidelines)can be cleaned by most property owners using common household cleaners or simple soap and water; if using bleach, extra caution is in order.

While demolition/removal of building components in of small areas of mold may not be required, in some cases removal/replacement of moldy materials permits valuable additional investigation for hidden mold, and may be easier than cleanup, particularly where surfaces or materials are in poor condition or where mold is on drywall or other components such as fiberglass insulation or duct work which can't be cleaned. If further investigation, renovation or repair discloses mold or conditions which cause growth of large areas of mold, professional cleanup/removal by an expert remediator would be needed.

How Should Large Areas of Toxic or Allergenic Mold be Handled?

Large areas of mold (more than 30 sq.ft. of contiguous problem mold): professional cleanup is needed by an expert remediator and is likely to involve significant expense.

"Large" is more than 10 sq.ft. according to the US EPA, or 30 sq.ft. per the NY City Guidelines. For instructions for remediation see the NY City guidelines at https://InspectAPedia.com/sickhouse.htm#action. If your remediator is not familiar with these guidelines s/he may not be properly informed to do the job.

What Good is Bleach in a Mold Remediation Project?

Though normally weI do not enthuse about "bleaching" mold (since leaving a dead mold spore in place can still be harmful and can leave toxins), careful cleaning of otherwise already HEPA-vacuumed debris-free surfaces with a proper bleach solution (5%) is an effective end measure for hard surfaces - not much use on upholstered furnishings.

Watch out: do not accept a mold remediation job that relies principally on bleaching surfaces.

The mold reservoir needs to be found, removed, its cause corrected, and all related surfaces cleaned (or non-cleanable materials thrown out). Then using a biocide, sanitizer, or bleach solution for final cleaning is ok provided the solution is used according to the manufacturer's directions and applied safely.

Harmfulness, Allergenicity, or Toxicity of "Dead" Mold Spores & Fragments of Mold Materials

• Ammann, Harriet M. "Is indoor mold contamination a threat to health." [PDF] J Environ Health 64, no. 6 (2002): 43-4.
  Excerpt:
  Penicillium
  
  Penicillium species have been shown to be fairly common indoors, even in clean environments, but certainly begin to show up in problem buildings in numbers greater than outdoors (Burge, 1986; Miller et al., 1988; Flannigan and Miller, 1994). Spores have the highest concentrations of mycotoxins, although the vegetative portion of the mold, the mycelium, can also contain the poison.
  
  Viability of spores is not essential to toxicity, so that the spore as a dead particle can still be a source of toxin. Important toxins produced by penicillia include nephrotoxic citrinin, produced by P. citrinum, P. expansum and P. viridicatum; nephrotoxic ochratoxin, from P. cyclopium and P. viridicatum, and patulin, cytotoxic and carcinogenic in rats, from P. expansum (Smith and Moss, 1985).
• Blundell, David F. "Proliferation of Mold and Toxic Mold Litigation: What Is Safe Exposure to Airborne Fungi Spores Indoors." Envtl. Law. 8 (2001): 389.
  Excerpt:
  
  … is a slow-growing toxic mold that is dark green to black.27 Pénicillium spores have the highest concentrations of mycotoxins and remain toxic even as dead particles.28 … No. 2] Mold and Toxic Mold Litigation 401 significant presence of two toxigenic molds.96 Relying …
• Burge, Harriet A. "An update on pollen and fungal spore aerobiology." Journal of Allergy and Clinical Immunology 110, no. 4 (2002): 544-552.
  Excerpt:
  
  During remediation, airborne spore counts and toxicity increased
• Clark, Judson Freeman. "On the toxic effect of deleterious agents on the germination and development of certain filamentous fungi."[PDF] Botanical Gazette 28, no. 5 (1899): 289-327.
• Curtis, Luke, Allan Lieberman, Martha Stark, William Rea, and Marsha Vetter. "Adverse health effects of indoor molds." Journal of Nutritional & Environmental Medicine 14, no. 3 (2004): 261-274.
• Davis, Pamela J. Molds, toxic molds, and indoor air quality. Vol. 8, no. 1. California State Library, California Research Bureau, 2001.
• Fung, Frederick, and William G. Hughson. "The fundamentals of mold-related illness: When to suspect the environment is making a patient sick." Postgraduate medicine 120, no. 1 (2008): 80-84.
• Fung, Frederick, and Richard F. Clark. "Health effects of mycotoxins: a toxicological overview." Journal of Toxicology: Clinical Toxicology 42, no. 2 (2004): 217-234.
• Henning, Stephen J., and Daniel A. Berman. "Mold contamination: liability and coverage issues: essential information you need to know for successfully handling and resolving any claim involving toxic mold." Hastings W.-Nw. J. Envt'l L. & Pol'y 8 (2001): 73.
  Excerpt:
  
  … other organisms. Mycotoxins are found in both living and dead mold spores. Even after being disinfected, materials perme- ated with mold must be removed. Allergic and toxic effects can remain in dead spores. Mycotoxins are …
• Hirvonen, Maija-Riitta, Marjo Ruotsalainen, Kai Savolainen, and Aino Nevalainen. "Effect of viability of actinomycete spores on their ability to stimulate production of nitric oxide and reactive oxygen species in RAW264. 7 macrophages." Toxicology 124, no. 2 (1997): 105-114.
• Jarvis, Bruce B. "Mycotoxins and indoor air quality." In Biological contaminants in indoor environments. ASTM International, 1990.
  Excerpt:
  
  Spores need not be viable to elicit a toxic effect, the dead spores can cause allergic reacuons … not point to a specific organism and yet extracts of the environmental samples prove quite toxic … and evaluate each culture for toxicity …
• Madelin, T. M., and M. F. Madelin. "Biological analysis of fungi and associated molds." In Bioaerosols handbook, pp. 361-386. CRC Press Boca Raton, FL, 1995.
  Excerpts:
  
  ... [p. 84] Aspergillus niger, A. fumigatus, Penicillium, etc. Immune systems respond whether such allergens are "alive' or 'Dead'. Consequently 'the viability' of such materials is less important perhaps than the presence of particular molecular species. … likewise it may be of no consequence whether airborne particles are alive or dead. Assay procedures described below relate to numbers, viability, infectivity, toxicity and allergenicity of … associated mold particles in air are viable, infective, allergenic or toxic, purely enumerative …
• Money, Nicholas P. Carpet monsters and killer Spores: A Natural History of Toxic mold. Oxford University Press on Demand, 2004.
  Excerpts:
  
  [p 12] ... This slide count does not discriminate between living spores and dead ones, but, since dead ones can still cause an allergic reaction and carry toxins, this subtlety is unimportant. The number of colonies that grow out over the agar in a culture dish usually provides a lower estimate of mold concentration, because the method reflects the number of live spores capable of germinating - not the ...
  
  [p. 32] Stachybotrys chartarum was first isolated in 1837 from wallpaper in Prague. It seems to enjoy a global distribution in buildings; and in addition to its prevalence on wet paper products, mycologists have isolated the mold from moldy leaves, soil, desert sand, the gut contents of bees, seeds, cat hair, and feathers.
  
  ... The prestige of Stachybotrys is a purely human illusion: Other molds are far more common and are immeasurably more important to life on Earth as agents of decay. Mycologists have described 74,000 fungal species, a number that means nothing without some benchmarks. [The author goes on to argue for the presence of many millions of mold genera/species, a number far greater than the 74,000 species that have been identified, named, studied - Ed. ]
  
  [p. 55] ... Proteins on the surface of a dead mold spore are just as allergenic as a protein on a live spore. Even fragments of spores or other components of a fungal colony can cause mast cell degranulation. But a living microorganism could certainly become a greater problem for someone with allergies if it were able to grow in the nasal passages or lungs. According to recent studies, Stachybotrys might be capable of doing this.
  
  [p. 58] Of greater concerns are mold toxins that clog biochemical machinery and destroy cells.
  
  [p. 68-69] ... Vesper and colleagues have recently shown that the toxin is localized in the cell wall of the spores and mycelium of Stachybotrys, and also that the protein diffuses away from spores when they settle in mice and rat lungs. They also claim that stachylysin can be identified in the blood seriumof people exposed to Stachybotyrys, which could lead to a highly specific clinical test for exposure to the mold. Might this toxin be the smoking gun in pulmonary hemorrhage?
  
  ... Harriet Burge, at the Harvard School of Public Health, used these numbers to assess the risk associated with spore inhalation. She calculated that in a room saturated with mold spores, a person might accumulate a few tenths of a nanogram of toxin over the course of a day. This isn't much, but it is important to recognize that the local concentration of toxin right next to each spore could be sufficient to injure a small island of cells. If thousands of spores reach the lung lining [or spore fragments - ed.], they could act as thousands of foci of dead and dying cells; spread over the lungs, illness seems more likely.
  
  Toxin release is a passive process, so even when a spore is dead, it can still act as a source of poisons. Quite recently, mold researchers have begun to realize that spores are not the only vehicles for mycotoxin transmission. ... But in addition to the release of spores, the researchers found that clouds of miniscule particles were ejected under the same conditions.
  
  For every spore, more than 300 of these cell fragments were released from the [ceiling] tiles. The particles are no bigger than bacteria, but they are certainly capable of carrying mycotoxins. If future experiments validate this prediction, we may be able to explain how people can become sickened in rooms with moderate spore counts: Tiny particles could mist lung linings with mycotoxins even whe very few spores are inhaled. If particle ejection occurs from colonies of Stachytbotrtys (experimental evidence for this has not been published), this would provide an efficient mechanism for mycotoxin delicery even if the larger spores were trapped in the upper airways.
  
  Trichothecenes and other toxins are examples of secondary metabolites. ... In addition to its toxic secondary metabolites, Stachybotrys releases other moleules that might be of clinical significance. Researchers are particularly interested in secreted proteases... their possible role as allegens ... The same enzymes might also be responsible for weakening lung tissue or damaging blood vessels: they certainly digest the collagens that account for much of the structural integrity of these tissues.
  
  [p. 157] 27. The potential role of mycelial fragments in delivering mycotoxins has been discussed a number of times in the book, but it may be worth underscoring the hypotyhesis. Because mycotoins are carried in the outer shell of the spores, any fragments of cell-wall material derived from mold colonies probably carry the same toxins as intact spores.
  
  Indeed, the fungus may be dead long before the toxin-bearing fragments are dispersed into the air by disturbance to the colonies. Fragments will not germinate on culture plates, so they could contaminate a room that appears to be free from mold when attempts are made to culture fungi from air samples. The small size of the fragments relative to whole spores, and their irregular shapes, would also hide these particles from investigators trained to count spores on microscope slides.
• Mahoney, Daniel P., and Jerome E. Spear. "Mold risk assessment & remediation." Professional Safety 48, no. 8 (2003): 20.
  Excerpt:
  
  Surface sampling is preferred over bulk sampling when a less—destructive method is Table 1 Common Indoor Molds & Health … Use of biocides is not generally recommended since dead mold spores are still allergenic, and some dead mold spores are potentially toxic (EPA ...
  
• Perry, Elizabeth L. "Why Fear the Fungus-Why Toxic Mold Is and Is Not the Next Big Toxic Tort." Buff. L. Rev. 52 (2004): 257.
  Excerpt:
  
  … Pearce, supra note 14, at 1, noting that the tiny spores produced by mold "may take an hour to fall one yard in dead still air … Toxic molds are so labeled because they may emit mycotoxins, 7 poisonous chemical by- products that either exist inside a mold spore or attach …
• Robbins, Coreen A., Lonie J. Swenson, Marrk L. Nealley, Bruce J. Kelman, and Ronald E. Gots. "Health effects of mycotoxins in indoor air: a critical review." Applied occupational and environmental hygiene 15, no. 10 (2000): 773-784.
  Excerpt:
  
  … Unlike a pure mycotoxin aerosol, a mold spore is a complex assortment of chemicals that may act as synergists or inhibitors in producing toxic effects …
• Rylander, Ragnar. "Microbial cell wall constituents in indoor air and their relation to disease." Indoor Air 8, no. S4 (1998): 59-65.
  
  Excerpt: … Stachybotrus atra is a hydrophilic fungus that can produce highly toxic macrocyclic trichothecenes … (1+3)-PD-glucan retains its biological activity even when the mold spore is dead and sampling
  for viable organisms is thus not sufficient for (1+3)-pD- glucan risk evaluations …
• Shaheen, Elias, Jennifer Fung, and Julie Wiesman. "Complete mold system." U.S. Patent Application 10/870,096, filed September 29, 2005.
  Excerpt:
  
  … You must clean up and remove mold contamination, not just kill the mold. Dead mold is still allergenic; some are potentially toxic …
• U.S. EPA, A BRIEF GUIDE to MOLD, MOISTURE, and YOUR HOME [PDF], Cleanup and Biocides, at https://www.epa.gov/mold/brief-guide-mold-moisture-and-your-home
  Excerpt:
  
  Biocides are substances that can destroy living organisms. The use of a chemical or biocide that kills organisms such as mold (chlorine bleach, for example) is not recommended as a routine practice during mold cleanup.
  
  There may be instances, however, when professional judgment may indicate its use (for example, when immune-compromised individuals are present). In most cases, it is not possible or desirable to sterilize an area; a background level of mold spores will remain - these spores will not grow if the moisture problem has been resolved. If you choose to use disinfectants or biocides, always ventilate the area and exhaust the air to the outdoors. Never mix chlorine bleach solution with other cleaning solutions or detergents that contain ammonia because toxic fumes could be produced.
  
  [p. 15] Please note: Dead mold may still cause allergic reactions in some people, so it is not enough to simply kill the mold, it must also be removed.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2021-05-26 by (mod) - reader wants a product that keeps mold from coming back

@Robert,

Thank you, that's a helpful criticism that helps me see where to be more clear. The purpose of this article is to explain the following points:

By NO means am I suggesting that we need to panic, give-up, bulldoze the house or take other such dramatic measures, not in reality and not even when speaking tongue-in-cheek or in hyperbole.

In fact panic or mycophobia itself is sometimes a greater health hazard than mold, and even if you're just-calmly-panicked, the risk is wasting money or spending it ineffectively.

Here are the practical facts of the matter:

There is NO product that "works" on "killing" "black" mold - in the sense that I will explain:

That's because there are so many errors in the statement itself.

1. Using bleach or other disinfectants won't kill "all" of the mold: I've sampled and processed in our lab a tremendous number of mold samples, surface samples, dust samples from surfaces and materials treated with disinfectants, sanitizers, bleach, and other "mold killers" only to find that I can virtually always find some spores that remain viable.

2. "Killing" mold, is incomplete: even if you could kill every spore, leaves, in many cases, particle (dead spores, hyphal fragments) that are still toxic: containing, for example, mycotoxins.

3. Killing the mold doesn't prevent new mold growth: - if you could "kill" all of the old on a surface that has not addressed the reasons mold grew in the first place. So ultimately you can expect the mold problem to recur.

4. "Black mold" is the wrong target. Among the hundreds of harmful mold genera/species that may be commonly found in or on building materials and surfaces, (and thousands that might be there but are less-common) some of them may look black or dark, but a tremendous number of them are other colors: red, green, brown, tan, white, yellow, orange, etc. a great many of of which, regardless of color, may be toxic, pathogenic, or allergenic.

So where did "kill black mold" come from? From hasty journalism and advertising opportunities.

The right approach to getting rid of mold

1. Find the mold
2. Remove it
3. Toss materials that can't be cleaned (carpet, carpet padding, for example)
4. Clean the exposed surfaces
5. Find and fix the leak or moisture conditions that caused the mold problem.

So do I ever use "bleach" or "cleaners" on mold?

Of course; I would use any common household cleaner, including some that contain bleach or disinfecting agents, to clean off mold from a hard surface that can be cleaned. That's more-appropriate for small DIY projects where the materials can be cleaned, where there is no worry about mold behind a surface (such as in a wall cavity), and where the size of the job is less than 30 sq.ft. of contiguous mold.

What about removing stains that remain on wood beams and framing:

If the wood will be covered by finished materials don't worry about the stains. Clean the surfaces, seal them if you wish, and finish restoring the building.

What about getting rid of mold stains on wood that remains exposed?

If you have, for example, exposed beams that were moldy, it's fine with me to use a bleaching agent to try to clean-up the wood after the end of a mold remediation job. Keep in mind that you're addressing only a cosmetic concern. Those moldy-stained wood fibres that are down in the wood (your point about sanding being useless are not harmful.

I used to think that those stains might form an inoculum that would speed the return of mold in the future should damp conditions recur, and that might be true, but in that case, the key point is that "damp or wet" conditions recur - if that happens you're going to have a new mold problem regardless of how nice or ugly those wood beams looked before.

So do I ever use fungicidal sealants?

There are some fungicidal sealants, including clear ones, that can be applied to clean beams and wood to reduce their propensity to take up moisture and thus to improve their mold-resistance in the future. The companies selling fungicides that claim that those "mold-proof" the material are, in my opinion and experience over-stating the protection that the products actually afford over the longer term life of the building.

I've not seen one independent, expert, mold-resistance study that demonstrates that the chemical fungicides in such sealants maintain their efficacy over the remaining life of the building in all of the conditions of moisture or other building failures that may occur.

So sure, I use fungicidal sealants, or in other locations, similar sealants such as a lacquer primer-sealer (Bin or Enamelac for example) where I have cleaned up mold contamination and where, even though we've fixed the water or moisture source, I want some extra "insurance" against moisture uptake in the wood materials over the longer life of the building, particularly in a difficult-to-maintain or infrequently-accessed-inspected area.

And in restoring antique and valuable wood flooring and furniture I've even worked with a Q-tip cotton swab soaked in a dilution of household bleach to work out small stains before cleaning off the bleaching agent and then re-finishing the wood surface by staining it to match and sealing everything.

On 2021-05-26 by Robert

Your post lists all the reasons not to use bleach, but does not give a product that works on killing black mold that removes stains and keeps it from coming back

. When you use any remedy suggested to clean the mold, a black stain still remains.

Even sandpaper cannot go deep enough to remove the stain. It would appear that a fungicide would work, but none are available in CA for a home owner and the natural ones still leave a stain. Perhaps bulldozing the house is the only solution for mold in the attic framing.

On 2021-01-06 by (mod) - using a fungicide on wood framing or building surfaces causes mycotoxins? Really?

@Steve,

It's fine to use Zinsser Mold Killing Primer on wood that has been cleaned, dried, and will be kept dry - in my OPINION you're painting or spraying-on an extra "insurance" against mold that works initialliy by fungicide and probably over longer-term principally by reducing the ability of the wood to pick-up moisture.

Watch out: however, "Killing" mold is the wrong approach as even a "dead" spore may still be toxic. Remove the mold, fix its cause, and then, sure if you like, add a fungicidal primer to reduce future mold-friendliness of the surface.

But using a fungicidal sealant is not harmful, and by making wood more-moisture-resistant, it may help keep up the wood's mold-resistance even after the efficacy of the chemical fungicide itself has waned.

I have not found evidence that fungicidal sealants increase mycotoxin production on building materials like wood framing - there should BE no mycoxins being "produced"if we have properly removed the mold and fixed its cause.

Perhaps you read some material like that I'll cite below referring to a relationship between some fungicides (or pesticides) and mycotoxin production in some food products, particularly grains.

if you have such an information source to which you refer, please point me to it as I'd like to read that material.

• Ellner, F. M. "Results of long-term field studies into the effect of strobilurin containing fungicides on the production of mycotoxins in several winter wheat varieties." Mycotoxin research 21, no. 2 (2005): 112-115.
• da Luz, Suzane Rickes, Paulo Cesar Pazdiora, Leandro José Dallagnol, Giniani Carla Dors, and Fábio Clasen Chaves. "Mycotoxin and fungicide residues in wheat grains from fungicide-treated plants measured by a validated LC-MS method." Food chemistry 220 (2017): 510-516.
• D'mello, Jp Felix, Ann MC Macdonald, David Postel, Wilko TP Dijksma, Aude Dujardin, and Cristina M. Placinta. "Pesticide use and mycotoxin production in Fusarium and Aspergillus phytopathogens." European Journal of Plant Pathology 104, no. 8 (1998): 741-751.

On 2021-01-06 by Steve - Zinsser Mold Killing Primer

I want to use Zinsser Mold Killing Primer, but I read somewhere that fungicides can actually increase mycotoxin production. Would this primer make my problem worse?

On 2020-12-04 by (mod) - I've sprayed the mold several times with a mold killer, but I can still smell it

Rita

Attempted to kill mold is a fundamentally incorrect approach to mold contamination.

Spraying surface will never remove a mold contamination that is also growing inside of a wall cavity or deeper in building materials.

And the mold odor you smell could certainly be from hidden mold in a wall, ceiling, or floor.

And even if your spray could kill all of the mold spores, which in my experience never happens, you are likely to be leaving particles that are still toxic or harmful, for example containing mycotoxins.

Please take a look at the explanation on the page above.

You'll see that the correct approach is to find and remove the mold, clean the exposed surfaces, and fix the leak or moisture problem that caused the mold growth in the first place.

Sprays are appealing because they're cheap and easy but they're basically a Band-Aid that is not likely to be successful.

On 2020-12-04 by Rita

I've sprayed the mold several times with a mold killer, but I can still smell it does that mean I haven't got all of it?

On 2020-10-23 - by (mod) -

Janette:

Mold spores or mycotoxins and MVOCs (think of gases not just particles) can affect breathing and health;

I can't say from your note if there's a problem in your apartment or not;

But a reasonable general guideline is this: if you notice substantial reactions, such as difficulty in breathing, when you enter a specific building or apartment and that stop or get better on leaving that environment, that's strongly suggestive of a problem. (Be warned that there could be a problem in a building and yet symptoms may also persist on leaving it so this is never a 100% sure guideline).

A second diagnostic is to answer the question: was there a leak in or around the apartment. If water entered ceiling, wall, or floor spaces and those areas were not investigated nor properly inspected and dried and cleaned, there could be a hidden problem there.

To help guide you in deciding on whether or not to take further action, I've prepared and ask you to take a look at

MOLD / ENVIRONMENTAL EXPERT, HIRE ?

Please take a look and don't hesitate to ask follow-up questions or to tell me what you think.

On 2020-10-22 by Janette

Hello. I am new to these issues; so forgive any basic questions.

On my partner’s and my return to our rented apartment home in West Seattle, from a month’s stay at an Air BnB, I noticed a mustiness in the air. Building management had emailed tenants they would be doing plumbing repair during the week before our return. (Ours is a 1930s brick building; and some of the pipes here had never been updated.)

At entering the apartment, I right away noticed a smell of mustiness. That was 6 days ago, now; yet ever since, I have experienced breathing problems, with need to wash out my nose & eyes 2-3 times a day (baby shampoo & salt-based nasal sprays), and to take a bronchial & nasal support supplement morning & evening.

While asking the manager about first floor rental opportunities (my partner is temporarily not walking, after tumor radiation in a hip socket _ the third floor seems impractical), I learned the old pipes on the first floor of our building had been entirely replaced.

The process of pipe replacement involves wall work & plaster particles as well as any mold disturbance; and such particles would explain the musty air. The sheets held the same smell, enough that they needed a machine-wash.

My not breathing completely freely is expected with seasonal allergy in the fall and spring; but this difficulty with breathing is quite more pronounced and troublesome than is usual. After reading a bit on your site, I realize mold spores may also be playing a role here, at home, in my physical response.

Note: The manager had mentioned our apartment might also have been ‘affected by the pipe replacement,’ in response to my commenting on spurting and popping water, when I’d first turned on the faucet. I was not sure what else, if anything, he might be implying but obviously I need to inquire further.

Mold (dark brown in color) has been a past issue in the grout of our yellow-tiled bathroom; so it most likely is in the wall, as well and could have been disturbed with any work that needed doing there.
My respiratory symptoms are most likely related to these building alterations.

Can you let me know what you think.

Appreciatively,
Janette
CounselingNW.Janette@gmail.com

On 2020-01-22 - by (mod) -

Sure, Karen,

Because proper mold remediation requires *removal* of the mold and then correction of the cause for its growth, low temperature is not in my opinion a limiting factor unless working conditions are so difficult that you don't trust the workmanship or thoroughness of the job.

Some moldy materials like carpeting or insulation or drywall cannot be cleaned and must be removed, the exposed surfaces cleaned, and then replaced.

Other moldy surfaces such as hard surfaces of tile floors or wood framing can be cleaned and possibly sealed.

Watch out: however; if the remediaton plan includes not just cleaning but also use of a fungicidal sealnt, both any liquid cleaners and any sealants will need to be used at temperatures approved by the manufacturers of those specific products.

In comparison, media blasting that cleans without relying on a (freez-able) liquid cleaning agent, is less temperature-vulnerable.

On 2020-01-22 by Karen/Larry Gardner

Can you confirm what the lowest temperature is acceptable in order to do mold remediation? We are in NW Indiana, and we are in the middle of winter.

We have a mold issue we want to address as soon as we can, but weren't sure it could be done effectively with our winter temps here. Areas to be treated are in our attic--the wood--and in our crawl space.
Thank you!
kareng183@gmail.com

On 2019-02-27 - by (mod) -

You need to discuss your question with your doctor right away. From what you described it could be very unsafe for your child to remain in the house if there is a mold contamination problem there. Killing the mold and even trying to clean the mold would be ineffective and dangerous with such a person present. Sorry I don't mean to be an alarmist but with no other information we just can't take chances with the health issues involved here.

On 2019-02-26 by Oma

Hi, thanks for an informative site, that gave me more info than I've found elsewhere.

We noticed that our boy's asthma has worsened since moving to this house. We removed wall to wall carpet and noticed a very slight improvement.
However, he was recently diagnosed with an autoimmune disease which is triggered by specific foods (these can't be determined by the usual skin prick tests). This condition is exacerbated by environmental allergens.

His symptoms aren't improving much after eliminating multiple food groups, so we suspected mold. An Exhale brand mold test reported high levels in the house. No breakdown of what genera.

It's going to take some time to find another housing alternative. Meanwhile, his condition can't improve until we get rid of the mold. As tenants, we can clean what we can, but the landlord hasn't shown any intention of remediation or assessment.

So, we purchased air filters, but need to purchase more. Can you tell us which type of filter is best suited? The HEPA ones will trap particles, but would spores remain trapped and proliferating in the filters? Others, such as Ecosphere or Molekule, claim to destroy mold spores.

My concern is whether or not "destroy" means rendered harmless or can still trigger allergic response.

Thanks so much for your help. We're getting pretty desperate.

On 2018-10-19 - by (mod) -

THanks for the follow-up; any time I can be of assistance, don't hesitate to ask.

You could do me a favor and shoot some photos of the moldy dollhouse before trashing it; they'd be helpful. Of the whole house and closeups of the moldy areas.

On 2018-10-19 by Jennifer

Thanks so much for that info! Actually I work at the Museum of Miniature Houses in Carmel, IN, and the dollhouse was a donation for our attic sale. It's in pretty bad shape anyway so I think I'll pass on the cleaning and just chuck it. We get some donations like that - things that have been in someone's attic or basement for year.

On 2018-10-18 - by (mod) - moldy dollhouse

Thank you so much for asking, Jennifer. This will be my first dollhouse mold consulting report.

Let's review the concerns with "dead mold":

First: in my experience, even when a moldy area appears dried out and "dead", some viable spores remain.

Second: any increase in moisture is likely to see a spurt in mold growth in the doll house since it is already inoculated with a colony of domrant dried-out but some-viable spores.

Third: even "dead mold spores" - if you could really kill 'em all - may be allergenic, toxic, or pathogenic, varying of course by the mold genera / species that are present (there will virtually always be more than one genera/ species).

The great news is that unless your doll house is bigger than any my daughters Michelle or Mara enjoyed, even if it's moldy, the total area of moldy surfaces is going to be less than 30 square feet of contiguous mold contamination. So you do not have to hire a professional mold remediator. Unless you are someone with particular allergy, asthma, or immune system vulnerabilities, you should be able to clean the mold yourself.

Use any household cleaner, and clean that off as well so that you don't leave a bleaching agent or a cleaner perfume in with the dollhouse occupants.

The bad news is that scrubbing tiny nooks and crevices in a dollhouse is some work. A small stiff paint brush or maybe a toothbrush may help.

So remove the mold.

And use the Add Image button to post some photos of the dollhouse before-and after if you can. That will let me comment further.

On 2018-10-18 by Jennifer

I was given a dollhouse that I believe has or had black mold. My question - if something like this did indeed have the mold, would the mold die once the dollhouse dried completely? thanks.

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