How Toxic Is Toxic Mold?

Our upstairs has basically been just for storage since the kids moved out. One bedroom in particular is used for nothing but storing stuff we never use, so I hadn’t been in there for a year or more.

Anyway, I went to stick some old hard drives in there the today, and was greeted with the sight of water damage in the ceiling. Apparently there is a small leak in the roof. It’s not enough to have made water drip onto the floor, but the ceiling has a stain and a small crack, and when I poked it with a screwdriver, it went right through. And there was a distinct smell of mold. Black mold, from looking at the screwdriver.

So I’m sure there’s a moldy mess in the attic, and I’ll probably let the pros handle that. My question is about the bedroom. If I can smell mold there, but there’s no sign of it on anything, is it still dangerous to be in it for even a minute?

Obviously I wouldn’t want to sleep in there, but if I open the windows and let it air out, is it safe to spend a few minutes at a time in there to move the stuff out so the workers can cut open the ceiling without getting moldy debris all over my stuff? Is everything in the room already contaminated, even though there is no visible mold?

Mold spores are the component that cause the toxic reaction in most people and the spores are invisible (at least, individually - you might see a dusting of them in the aggregate).

It’s also worth noting that the mold you see on a surface is like the tip of an iceberg (or the flower on a weed) - the rest of the mold probably has “roots” going into wood, sheetrock and other soft surfaces. Some people clean a surface with bleach and are surprised when mold grows back.

Not all molds are equally dangerous and it might take a pro to identify them.

There’s some debate about how much exposure is dangerous, but many of the worst cases result from exposure over long periods of time. I know someone who insists that five minutes of exposure causes a headache (but who has a track record of false positives), and another who was diagnosed with a mold allergy/autoimmune disorder after years of exposure and gradually-worsening symptoms. Moving out of the area to a place where his mold didn’t occur was enough to improve symptoms.

Personally, I think you’d be fine moving stuff around for a few minutes or hours, but I know people in the mold remediation business who wouldn’t. Be aware that moving things around can help move spores around the rest of the home.

Most mold is not toxic, although it can be a problem for allergic individuals. It’s unlikely that being in a damp or moldy environment intermittently is “dangerous.”

Controlling it is a matter of finding the source of the moisture, correcting it, and keeping the humidity levels in your home at or below about 60 percent. Clothing, paper products and other porous items may need to be discarded; not because they’re any danger but because it’s not always possible to clean the mold out without damage to the material.

Well, that link was very encouraging. Now I’m thinking maybe if I get one of those respirator masks, I should be able to clean up the attic myself, assuming the moldy area is not much bigger than the stain on the ceiling indicates. Am I getting overconfident?

I don’t think so, personally. As long as you can identify where the excess moisture is coming from, control it and use a dehumidifier or fans or whatever else to keep the humidity down, it’s really not a big deal usually.

Don’t know where you live, but sunlight is a great mold-killer! If you can get the stuff from the bedroom outside for a couple of dry, sunny days, it will go a long way to killing off the spores.

/I’m a painting contractor in Michigan and run into mold issues frequently. Really, it is rarely a big deal, unless you have someone in the house with allergies or sensitivities to mold. And it’s usually a fairly easy DIY fix.

I’m going to chime in with “I don’t think so, either.”

I work with a general contractor and we, too, frequently encounter mold during our work. At most, I’ve had some minor irritation/runny nose, despite being prone to allergies.

Yes, by all means wear a mask. Open the windows. Reduce humidity. Today, we put a wheelbarrow under a window and chucked water-damaged drywall out the window so we didn’t have to drag it through the rest of the house, but that’s as much because of dust clean as mold (and yes, there was mold present).

The time you need to be concerned is if you have lung problems, or if someone in your house has a depressed immune system or serious chronic illness. Such people probably shouldn’t be cleaning up mold, and should consider being elsewhere until the clean up is complete.

If you start the clean up and find it’s more than you can handle then hire someone to finish the job. Be sure to tell them everything you’ve done and what you’ve used (bleach, some other chemical, whatever) so they are better informed when they do the job.

Thanks very much for the responses.

We had a mess under a leaky deck stairway. Mold guys wanted $3400 to straighten it out. We masked up, put in some fans and got rid of all the black drywall. After everything dried out, we did a couple of applications of bleach in water with a small sprayer. When that dried out, the 2x4s looked like fresh wood and the mold stayed gone. When I get around to it, I’ll put some sheetrock back, but we did the work 2 years ago.

Do you know those bug fogger bombs?

For cleaning out roaches & suchlike?

They make disinfectant bombs that can kill mold, too.

Ah for the good old days when “TOXIC MOLD!!!OMG!!!” was just mildew.

Some molds produce mycotoxins under certain conditions. Mycotoxins cause respiratory irritation. In a healthy adult, it can trigger sinus/allergy/headache type stuff. Wear a mask, don’t work around it every day for 30 years and don’t have any infants, elderly or anyone who has problems with their immune system help you.

Yeah, but there’s still clean up to do. Even dead mold and mildew can be irritating.

Seems like many comments are taking a rather Cavalier approach to a rather serious topic. To tell people to just “deal with it on their own” without knowing the scope of the problem is irresponsible.

It’s true that mold issues are often blown out of proportion, but there are some real dangers present.

There are literally thousands of types of mold. 25 % of the earth’s biomass is mold. So it’s something we deal with everyday. However, mold can be a pesky allergens. Like other allergies, some are not allergic, some mildly so and some are seriously allergic (i.e. food allergies that can cause serious health problems).

There are some particularly troublesome molds that can be found in home environments. Aspergillus/Penicillium is quite common when dealing with a mold remediation and many people are very allergic causing a variety of respitory problems.

Stachybotrus (typically referred to as “black mold”) is less common but more dangerous in that it can produce mycotoxins which have been shown to cause neural damage.

The only way to know is to have an air quality test done by an approved laboratory like Emlab or EMSL. If you have a certified mold inspector take these tests and send them off you’ll get a report of what kinds of mold you have present and in what concentrations. These concentrations should be compared to the outside ambient air to determine if they in are “elevated” or “extreme” amounts.

Only then can it be determined what kind of remediation, if any, needs to be done, either by you or professionals.


The OP has a leak in the ceiling. We’re not talking about an oozing, blob-like mass leering at whomever opens the door to the room.

Most likely this really is something the average person can handle without extensive lab testing. Seriously, do we want to require expensive experts for every aspect of our lives?

Brocks is leaving the attic to the experts, as stated. The room beneath, though should be well within the range of average person clean up. Open the windows, air it out, move what’s salvageable, use bleach/disinfectant on what can be treated with that, toss what’s not salvageable. This is not rocket science.

Color me suspicious. When a whole industry has grown up, complete with “mold inspectors” and “approved laboratories” it seems to me that this industry has a financial stake in scaring people. We have lived with mildew for the entirety of mankind’s existence. Only in the past few decades have we built it up into the Dread Black Mold.

My point is that none of us…including me…do not know the scope of the problem and therefore shouldn’t advise what needs to be done. If the op truly has “experts” on board then they can advise him if other areas of his home need to be remediated and by whom.

Again without testing you do not know if you have a non-issue or something more serious. You cannot determine that by a visual inspection alone.

I certainly do not subscribe to the “scare em” technique. But I also do not subscribe to the “ignore it and hope it ain’t a problem” approach. Typically if a homeowner is worried enough to post somewhere like this, the problem warrants an air inspection.

It doesn’t take much Stachy to pose a significant health risk. Now you could have quite a bit of Cladosporium or Basidiospores and not be in as much trouble. Are you prepared to advised the OP on which is which? :wink:

That’s what they said about asbestos and lead paint. :eek:

And yet, somehow, the species survives. :rolleyes:

As a species, yes. The individuals who wheezed their way to death from mesothelioma are just as dead as if you’d shot them. It’s not 99.9% safe for everybody, it’s 100% safe for 99.9% of the people and 100% fatal for the one in a thousand.

Well, my common-sense approach would be this: How often have you been sick this past winter? I’m talking about bronchitis, sinus infections, pneumonia. When given antibiotics for respiratory infections, does the first round of medication work, or do you have to go back for a second, or even a third antibiotic?

Have you had allergies during the summer which have gotten worse? Asthma?

Have you had an increase in headaches?

If you’ve answered “None of the Above,” then I say with a mask, open windows, and lots of fans, you might be okay to work for small periods of time in the bedroom. Take a shower when you are done, throw your clothes straight into the washer and wash immediately.

Depending on WHERE the water went from the roof leak, it could be more than just the ceiling. If water dripped down through the walls, there’s trouble ahead. After you have the roof and attic space inspected and you’re given an estimate, call your insurance agent. You might be able to get some help there.