# How bad is black mold?



## Mark Harvey (Apr 20, 2009)

A local community centre removed some drywall and found some "black stuff" which I assume is mold. Can this be sprayed with a disinfectant (sp) or should it be totally removed? Is it considered a health hazard? They were planning to leave it and drywall over the area. Any other remedies?
Thanks


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## daveb1 (Jan 15, 2010)

Black mold can be a serious health hazard!It can be treated if it is only a small infected area but removal of all infected material is best.Mold also needed moisture to grow.Check for plumbing leaks,rain infiltration even small holes in vapour barrier can let enough moisture through.Don't just hide this behind drywall you could have a very sick building!


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## Mark Harvey (Apr 20, 2009)

Thanks Dave. That's what I thought but needed a "second opinion".


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## daveb1 (Jan 15, 2010)

Try googling stacci botrus


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## epson (Jul 28, 2010)

Ok let’s see you asked how bad is black mold well it can cause many health problems, ranging from minor to severe. The most common problems are similar in nature to allergies, such as runny nose, headache, sore throat and irritated eyes. More serious problems can occur, such as dizziness and difficulty concentrating. Black mold is a dangerous byproduct of moisture entering into your house and remaining trapped there for a period of time. Mold is a living organism, similar in nature to fungi such as mushrooms that reproduce by spores. These spores are released into the air and can cause detrimental damage to our bodies if inhaled, ingested or exposed to skin. 

The most common place to see black mold is where a constant leak provides a water source, such as under a toilet, near a shower or in a basement behind drywall where there is a moisture problem. Flooding also tends to cause bad outbreaks of black mold and you should remove all drywall and items infected with black mold. Most people can take care of minor and localized cases, as long as they follow strict safety guidelines. If it is more serious a professional should be called to ensure the mold is remediated properly and safely.


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## Thurman (Feb 9, 2009)

How bad can Black Mold be: In my case, two days in an out-of-town hospital. I had re-built a bath floor after a leaky toilet seal destroyed it. While working on it I noticed the dark colored "tree branch" looking thingy's growing on the floor joists. I got this stuff all over my arms while working on this project, but "thought" I was washing up well enough each day before leaving the job site. About two weeks after exposure, while attending a funeral out-of-town, a cousin who is a nurse noticed all those red bumps all over my arms and recommended immediate Doctor's care. It's called "Folliculitus" (sp). That Black Mold stuff will go through the pores of your skin, get into your blood stream, infect your entire blood supply, and show up looking like the measles at each hair follicle. Immediate hospitalization and I.V.'s in both arms. Been there, done that, DO NOT want to do this again.


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## WirelessG (Mar 22, 2009)

Thurman said:


> How bad can Black Mold be: In my case, two days in an out-of-town hospital. I had re-built a bath floor after a leaky toilet seal destroyed it. While working on it I noticed the dark colored "tree branch" looking thingy's growing on the floor joists. I got this stuff all over my arms while working on this project, but "thought" I was washing up well enough each day before leaving the job site. About two weeks after exposure, while attending a funeral out-of-town, a cousin who is a nurse noticed all those red bumps all over my arms and recommended immediate Doctor's care. It's called "Folliculitus" (sp). That Black Mold stuff will go through the pores of your skin, get into your blood stream, infect your entire blood supply, and show up looking like the measles at each hair follicle. Immediate hospitalization and I.V.'s in both arms. Been there, done that, DO NOT want to do this again.


WOW. I thought it would have been limited to respiratory issues.

I read the other day that mold on cheese grows 1" roots into the cheese, so soft moldy cheese should not be eaten and hard moldy cheese should only be eaten if 1" is cut from all 6 sides. (I've only ever thrown out moldy cheese.)


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## bluebird5 (Jan 24, 2011)

DON'T COVER IT UP!!! tear out everything that you can that has it on it obviously you cannot take out structure but the mold has to be cleaned off with bleach and or hydrogen peroxide and you need to see where the moisture is coming from


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## Maintenance 6 (Feb 26, 2008)

Black mold is usually associated with Stachybotrys which is a common mold that will appear on building materials in damp conditions. Any material that has suffered a mold infestation and cannot be cleaned, should be removed if possible. Drywall, wallcoverings and carpet should be discarded. Where removal is not practical, then a thorough cleaning should be conducted. That means a scrub down with a fungicide (bleach is the cheapest and easiest). Everything then needs to be thoroughly wiped up, dried and then sealed. It goes without saying that the moisture issue needs to be remedied to prevent a re-occurance. Molds produce mycotoxins which are basically very nasty chemicals. Think of some of the most nasty chemicals you can and chances are a mold produces them somewhere. They produce these (1) as a method to digest food and (2) as a defense against other molds (protecting their territory). Over 200 mycotoxins have been identified just from common molds. Some people have a lower tolerance for these than others. Apparently Thurman is one of those unfortunate individuals with a very low tolerance. Stachybotrys is not the only toxigenic mold. Cleaning up is very important since even dead, dismembered mold corses can be an allergenic to some folks.


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## pyper (Jul 1, 2009)

The mold remediation guys suggested cleaning our project with TSP instead of bleach. Most of the problems with most mold are reactions to the spores, and the reactions are the same if the spores are living or dead, therefore the best practice is to _not _use bleach -- because then you can't see if you've cleaned it all up.


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## Maintenance 6 (Feb 26, 2008)

There is a lot of BS out there telling people that bleach won't kill mold. Not sure who your mold guys are, but bleach is very effective at destroying mold. In fact it is one of the few products that will break molds down to their component parts. Most mold companies won't use bleach because of the compound gases that can form from sloppy use and it's also not good PR for a company charging you megabucks to show up on site with household bleach. TSP will certainly kill it. So will lemon juice and a whole host of other things. There are a lot of things that kill molds. The problem with bleach is that most people tend to overuse it. 10% is sufficient. Higher concentrations run the risk of creating chloroform compound gases that are more dangerous than the mold. You can certainly see if the area is clean no matter what product you use. Some people may have reactions to spores, but they are far from the solitary cause of allergic reactions. Mold spores are everywhere, but they will be found in higher than normal concentrations in the area of an active colony. The important thing here is to recognize if you are susceptable and protect yourself accordingly. Second is, regardless of what you use to clean up, to completely clean up everything, including wiping up any mold debris. As I said, even dead mold carcasses and their parts can be an allergen. The biggest part of the remediation process is knowing when to clean and when to tear out and throw away. Not everything can be saved by cleaning. 
....... By the way, I am one of those mold remediation guys...... and have been for about 10 years.


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## pyper (Jul 1, 2009)

Maintenance 6 said:


> There is a lot of BS out there telling people that bleach won't kill mold. Not sure who your mold guys are, but bleach is very effective at destroying mold. In fact it is one of the few products that will break molds down to their component parts. Most mold companies won't use bleach because of the compound gases that can form from sloppy use and it's also not good PR for a company charging you


EPA disagrees (not that they know everything).

"The purpose of mold remediation is to remove the mold to prevent
human exposure and damage to building materials and furnishings. It
is necessary to clean up mold contamination, not just to kill the mold.
Dead mold is still allergenic, and some dead molds are potentially
toxic. The use of a biocide, such as chlorine bleach, is not
recommended as a routine practice during mold remediation, although
there may be instances where professional judgment may indicate its
use"

Emphasis added.

http://www.epa.gov/mold/pdfs/moldremediation.pdf

One of our mold guys was a certified industrial hygienist. He seemed to know a lot more than the other two, but all three agreed on not using bleach.


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## Michael Thomas (Jan 27, 2008)

Thurman,

Dermatophytic folliculitis is not AFAIK the result of infection by the types of mold which grow in structures, it's caused by fungi which infect living organisms - did they culture the infectious agent, and do you happen to remember what is was?


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## Maintenance 6 (Feb 26, 2008)

pyper said:


> EPA disagrees (not that they know everything).
> 
> "The purpose of mold remediation is to remove the mold to prevent
> human exposure and damage to building materials and furnishings. It
> ...


Yup. But not because it doesn't kill mold. No-where will you find the EPA telling you that bleach won't kill mold. In fact, right after Katrina, the EPA was advising everyone in the flood zone to use bleach. Why? Because it was cheap, easy to use, effective and readily available.


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## Michael Thomas (Jan 27, 2008)

Chlorine bleach and mold: http://www.spore-tech.com/viewCategory.asp?idCategory=78


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## Maintenance 6 (Feb 26, 2008)

Michael Thomas said:


> Chlorine bleach and mold: http://www.spore-tech.com/viewCategory.asp?idCategory=78


Another magic mold killer site!!!
Here's another for those interested. http://zapatopi.net/afdb/

And here's one with some useful info: http://www.jacionline.org/article/S0091-6749(04)00083-1/abstract

In particular read the paragraph under conclusions. Also notice that Stachybotrys was one of the specific molds used for the test.


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## BigJim (Sep 2, 2008)

What is TSP? I have tried straight bleach over and over on a place and it just comes back over and over. We will be doing a complete bath make over soon and know for a fact there is mold behind some of the walls and there will be materials we don't wish to remove as it is structural.


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## Maintenance 6 (Feb 26, 2008)

TSP is Trisodium phosphate. It is a good first step cleaner, but not the product of choice for disinfecting. I would tend to believe that if you've bleached it effectively and have a recurring problem, then you need to look for a moisture issue. Common household molds need a few things to thrive: Mold spores, which are everywhere and impoissible to completely eliminate, moisture greater than 60%RH (usually the main culprit), temperatures in the range of 40-110 degrees, and a food source (any organic material, drywall paper or wood is perfect). The only one that is really controllable is moisture. Completely clean the area, wipe up all the debris, disinfect with a fungicide, dry the area thoroughly and seal the material. Kilz and Zinsser both make sealers that work. Test the area for moisture content. Areas like grout joints, corners of showers that get re-wetted tend to get reinfected and require ongoing cleaning. The best prevention is to keep things clean and dry. you want to be careful using straight bleach. You are breathing some nasty stuff.


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## ratherbefishin' (Jun 16, 2007)

M6 is right on the money across the board.:thumbup:

And about the bleach, it wasn't just EPA's recommendation. The first FEMA drops here after Katrina included drinking water, ice, and......drumroll......bleach.

Sealing after cleaning is the key to keep it from coming back. BIN is my "go to" on structural members.


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## BigJim (Sep 2, 2008)

Maintenance 6 said:


> TSP is Trisodium phosphate. It is a good first step cleaner, but not the product of choice for disinfecting. I would tend to believe that if you've bleached it effectively and have a recurring problem, then you need to look for a moisture issue. Common household molds need a few things to thrive: Mold spores, which are everywhere and impoissible to completely eliminate, moisture greater than 60%RH (usually the main culprit), temperatures in the range of 40-110 degrees, and a food source (any organic material, drywall paper or wood is perfect). The only one that is really controllable is moisture. Completely clean the area, wipe up all the debris, disinfect with a fungicide, dry the area thoroughly and seal the material. Kilz and Zinsser both make sealers that work. Test the area for moisture content. Areas like grout joints, corners of showers that get re-wetted tend to get reinfected and require ongoing cleaning. The best prevention is to keep things clean and dry. you want to be careful using straight bleach. You are breathing some nasty stuff.


I do appreciate that information, that is what we will do. You are right about there still being moisture. You are also right about using straight bleach, that stuff is rough on the lungs. This is a relief to know, thanks for your time to let us know.


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## chrisBC (Dec 28, 2010)

I worked in the restoration industry for about four years, dealt with mold on a daily basis. It won't kill you, a lot of people think you need guys in white suits in. However, it's not healthy and you don't want it around. I've seen bleach used many times on the job for minor stuff. If the drywall/framing is rotted in any way you should replace it, think what you would do with your own house.


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## Level (May 18, 2011)

Maintenance 6 said:


> There is a lot of BS out there telling people that bleach won't kill mold. Not sure who your mold guys are, but bleach is very effective at destroying mold. In fact it is one of the few products that will break molds down to their component parts. Most mold companies won't use bleach because of the compound gases that can form from sloppy use and it's also not good PR for a company charging you megabucks to show up on site with household bleach. TSP will certainly kill it. So will lemon juice and a whole host of other things. There are a lot of things that kill molds. The problem with bleach is that most people tend to overuse it. 10% is sufficient. Higher concentrations run the risk of creating chloroform compound gases that are more dangerous than the mold. You can certainly see if the area is clean no matter what product you use. Some people may have reactions to spores, but they are far from the solitary cause of allergic reactions. Mold spores are everywhere, but they will be found in higher than normal concentrations in the area of an active colony. The important thing here is to recognize if you are susceptable and protect yourself accordingly. Second is, regardless of what you use to clean up, to completely clean up everything, including wiping up any mold debris. As I said, even dead mold carcasses and their parts can be an allergen. The biggest part of the remediation process is knowing when to clean and when to tear out and throw away. Not everything can be saved by cleaning.
> ....... By the way, I am one of those mold remediation guys...... and have been for about 10 years.


HI 
How do I tell its black mold and when I use the bleach mix will it react with the mold? I have a picture can you tell if that is black mold
Thanks for any help 
Level


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## Maintenance 6 (Feb 26, 2008)

It doesn't matter if it's black mold or any other color. You treat it the same. 1) Solve the moisture issue that created an environment for it to live. (60% or greater RH, .6 or greater water content for common molds) 2) Clean it. Wipe it. Scrub it. Sand it off. Whatever it takes. 3) Treat it with a fungicide. Bleach, or any of the other well known mold killers. 4) Get it dry. 5) Seal it. Bin, Kilz, Fosters, etc. All of these companies make sealers for areas that were afflicted with mold. They aren't anything special, but have a fungicidal chemical included in them. They are not a substitute for steps 1-4. Mold is not reactive. Apply something it doesn't like and it will die. It doesn't turn into anything more sinister than what it already is. You have to eliminate it's comfortable environment (moisture). You have to clean it to remove all of the allergens. Even dead mold carcasses and left over mycotoxins are allergens to some people. You treat porous surfaces with a fungicide to kill any left over hyphae or mold that is hidden or can't be reached. Seal it to lock down any residual hyphal/spore/fungal fragments and for appearance.


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## Michael Thomas (Jan 27, 2008)

Maintenance 6,

Can you provide us with objective evidence (for example, testing from a non-commercial source) demonstrating that chlorine bleach _at any concentration_ is effective at "killing mold" in a porous organic surface such a typical 2x4" wall stud?

If not, what is the source of you opinion?


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## Michael Thomas (Jan 27, 2008)

As for "Black Mold": 

Health Effects of Moulds (Molds): State of Knowledge
Indoor Fungi!


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## bob22 (May 28, 2008)

Michael: good site.
Also: http://www.ncbi.nlm.nih.gov/pubmed/16159635 for:
*Aerosolized sodium hypochlorite inhibits viability and allergenicity of mold on building materials.*


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## Maintenance 6 (Feb 26, 2008)

A study by the University of Arizona found that concentrations of Sodium Hypochlorite (common bleach) as low as 2.4%, not only killed mold but broke down the organisms to their component parts to such an extent that they were rendered harmless and could not be considered an allergen. That said, nowhere will you find a mold remediation product that legitimately claims to kill mold that is embedded in an organic material. In order to be effective, any fungicide must make physical contact with it's prey. Hence the reason for appying a sealer as a final step. To lock down any organism or component parts of organiasms that cannot be reasonably dis-infected.

http://www.jacionline.org/article/S0091-6749(04)00083-1/abstract


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## Michael Thomas (Jan 27, 2008)

Thanks to you both. I found the full text of the first study, which produced good results with Sodium Hypochlorite on gypsum board, OSB and plywood, I could not find the full text of the second, and could not determine what materials were tested.

Here's the rub: the tests do not reflect what I see in the field, which is that 2-5% Sodium Hypochlorite does not effectivly suppress most molds on porous organic materials which as softwood 2 x 4"s.

I do not not know why I observe this difference, the first thought that comes to mind is that materials like OSB and plywood contained binders and resins which may act to make them a "less porous surface" than some other building materials, and makes them less akin to the non-or minimally porous surfaces on which everyone (as far as I know) agrees that Sodium Hypochlorite is highly effective.

Don't get me wrong. I'm not a "Sodium Hypochlorite Denier", and I'm just fine SH being demonstrated to be highly effective on highly porous organic surfaces. and I am impressed with the results on the materials tested, which exceeded my expectations.

It's just that when you get to highly porous organic materials. it becomes a question of "Who are you going to believe? The Lab studies, or your lying eyes"?

And given the level of concern created by mold for many of my clients, and the amount of money spent on mold remediation in the US every year, I'd love to see some research to close the gap between the lab results and my field observations - if application standards for SH can be developed and demonstrated as highly effective on entire typical residential gypsum board/wood stud wall structure, that would be a Very Good Thing.


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## Maintenance 6 (Feb 26, 2008)

One must be careful with visual observations on porous surfaces. Molds produce mycotoxins. These are chemicals that molds use to digest food sources and as a defense against competing molds, parasitic molds and bacterias. Not all mycotoxins are a problem, yeast produces CO2 to make bread rise, while some produce ethanol compounds to create beer. Others can be a whole host of very nasty chemicals. These chemicals usually cause staining which should not be confused with viable mold colonies. That is why most remediators use final step sealers that are heavily pigmented. It produces the impression that the effected area is completely clean even though a clear sealer would do just as well at locking down any stray mold fragments. With the possible exception of an isolated blotch, I would never recommend, nor try to remediate mold on gypsum wallboard. Whatever level of moisture created the mold, also likely destroyed the structural integrity of the wallboard. It is such a cheap material that it should be considered disposable. 
The link posted about the health effects is probably the best written that I've come across and matches what I've learned over the past dozen years about mold. Unlike toxic materials and chemicals that have threshold limits of exposure, you won't find any for mold.
I understand your comment about the study of effectiveness of bleach on porous surfaces. There are a few studies that were conducted, but they were not very scientific and the documentation is seriously lacking. The only one I have read that has credence in my opinion is one that showed how ineffective ozone was in mold remediation.


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